Atherosclerosis

Editorial Board

2010-09-01

Elevated heart rate and cardiovascular outcomes in patients with coronary artery disease: Clinical evidence and pathophysiological mechanisms

2010-02-12

Abstract: There is an established body of evidence from epidemiological studies which indicates that an elevated resting heart rate is independently associated with atherosclerosis and increased cardiovascular morbidity and mortality, in both the general population and in patients with established cardiovascular disease. Clinical trial data suggest that in patients with coronary artery disease, an elevated heart rate identifies those at increased risk of adverse cardiovascular outcomes, and that lowering of heart rate may reduce major cardiovascular events in patients with an elevated heart rate and symptom-limiting angina. These results suggest that an increased heart rate may have an adverse impact on the atherosclerotic process and increase the risk of a cardiovascular event in patients with coronary artery disease. The precise pathophysiological mechanisms that link heart rate and cardiovascular outcomes have yet to be defined. Possibilities may include indirect mechanisms related to autonomic dysregulation and those due to an increase in heart rate per se, which can increase the ischaemic burden and exert local haemodynamic forces that can adversely impact on the endothelium and arterial wall. For these reasons, heart rate should be considered as a therapeutic target in the treatment of patients with coronary artery disease.

Association between change in plasma triglyceride levels and risk of stroke and carotid atherosclerosis: Systematic review and meta-regression analysis

2010-05-11

Abstract: Background and purpose: The contribution of modifying non-low-density lipoprotein cholesterol (LDL-C) levels to reduce stroke risk remains uncertain. The aim of this study was to investigate the association between treatment-induced change in plasma triglyceride levels and risk of stroke and progression of carotid intima-media thickness (CIMT).Methods: We performed a systematic review and meta-regression analyses of randomized controlled trials of lipid-modifying treatments selected from a PubMed search on literature published from 1966 to 2008.Results: We identified 64 randomized controlled trials (active groups, n=96,807; control groups, n=98,681) that tested lipid-modifying drugs and reported triglyceride levels and stroke outcome. Extracting data from placebo groups, we found a statistically significant association between baseline triglyceride levels and stroke risk (adjusted relative risk [RR], 1.05 per 10-mg/dL increase; 95% CI, 1.03–1.07). Except for a trend in fibrate and niacin trials, there was no evidence of any relationship between degree of triglyceride change and stroke incidence. In multivariable meta-regression analysis including baseline and change in LDL-C, only change in LDL-C was associated with log risk ratio of all strokes (RR reduction, 4.5% per 10-mg/dL reduction; 95% CI, 1.7–7.2; P=.003). Similarly, taking into account 26 randomized controlled trials reporting CIMT outcome, LDL-C reduction was associated with reduced CIMT progression (−3.0μm/y per 10-mg/dL reduction; 95% CI, −5.5 to −0.4; P=.03).Conclusions: In view of the limitations of meta-regression analysis and CIMT measures as surrogate endpoints in lipid-lowering drugs trials, additional studies are needed to more precisely quantify the detrimental effect of triglyceride levels on stroke risk and to establish the efficacy of triglyceride-lowering therapy in addition to LDL-C reduction.

Genetic and epigenetic mechanisms and their possible role in abdominal aortic aneurysm

Smriti M. Krishna, Anthony E. Dear, Paul E. Norman, Jonathan Golledge — 2010-03-29

Abstract: Abdominal aortic aneurysm (AAA) is a common disease associated with significant cardiovascular morbidity and mortality. The pathogenesis of AAA is poorly defined, making targeting of new therapies problematic. Current evidence favours an interaction of multiple environmental and genetic factors in the initiation and progression of AAA. Epigenetics is the term used to define the properties of the genome that are not explained by the primary sequence, but are due to the modifications of DNA and/or associated proteins. Previous research indicates the association of gene specific promoter DNA hyper-methylation and global DNA hypo-methylation with atherosclerosis. Evidence also suggests an important role for epigenetic processes such as histone acetylation in cardiovascular diseases including atherosclerosis and restenosis. Altered DNA methylation or histone acetylation occur in inflammation, cellular proliferation and remodelling processes and therefore maybe relevant to the pathology of AAA. Important risk factors for AAA, including cigarette smoking, older age, male gender and hypertension, have been linked with epigenetic effects and thus could act in this way to promote AAA. In this review, we discuss the potential role of epigenetic mechanisms in AAA. Since epigenetic alterations are to some extent reversible, further study of this area may identify new treatment targets for AAA.

Reduction of endoplasmic reticulum stress—A novel mechanism of action of statins in the protection against atherosclerosis

2010-05-31

Abstract: Fatty-acid-induced endoplasmic reticulum stress has been recently described as a novel mechanism involved in the genesis of atherosclerosis. Here we show that statins, a class of drug widely employed in the clinical management of hypercholesterolemia, reduces lipid-induced macrophage endoplasmic reticulum stress in an isolated cell system and in LDL receptor knockout mice. Given the importance of endoplasmic reticulum stress as an inducer of inflammation, we suspect that the novel mechanism of action herein described for statins may play a major role on its beneficial effects in the prevention of cardiovascular disease.

Animal models of atherosclerosis: More than mice

Lisa R. Tannock, Victoria L. King — 2010-07-20

Despite the complexities and intricacies of human atherosclerosis our understanding of the underlying processes is growing, in no small part due to the use of animal models of atherosclerosis. Human atherosclerosis is difficult to study as the lesions evolve over years to decades. However, by utilizing small animal models in which atherogenesis can be induced over shorter periods of time (weeks to months) current research can investigate the pathogenic mechanisms involved at various stages of development. Much of our recent advances in atherosclerosis research have come from the use of murine models, in which atherosclerosis can be induced via genetic and/or dietary manipulations over relatively short periods of time. Further, the ability to fairly easily alter the mouse genome, for example over-expressing or deleting a gene of interest, has allowed direct testing of the role of certain proteins in various stages of atherosclerosis development. The relative low cost, easy access, high fertility, and availability of numerous biological tools have made murine models the apparent first choice for animal studies of atherosclerosis. However, there are numerous drawbacks to the use of murine models that are often overlooked, and new models of atherosclerosis are urgently needed by the research community to expand our understanding and allow research beyond the limitations of murine models.

Eicosapentaenoic acid (EPA) from highly concentrated n-3 fatty acid ethyl esters is incorporated into advanced atherosclerotic plaques and higher plaque EPA is associated with decreased plaque inflammation and increased stability

Antonis Zampelas — 2010-07-20

Since the early 1970s when Bang and Dyerberg observed an association between fish consumption (mainly seal and whale) and reduced morbidity and mortality from cardiovascular diseases in Greenlanders , a vast amount of research has been carried out, including clinical trials with various end points of the disease, as well as metabolic studies, investigating possible mechanisms for these protective effects.

Induced pluripotent stem (iPS) cells and endothelial cell generation: SIRT-ainly a good idea!

Rute Moura, Gian Paolo Fadini, Marc Tjwa — 2010-07-20

Regenerative medicine holds great promise to broaden the therapeutic window in various diseases in which surgical and medical treatment options have reached their limits of benefit, including ischemic heart/limb disease and atherosclerosis. Indeed, a new era of medicine would commence if diseased cells could be safely and efficiently replaced by new ones (i.e. cell therapy); for instance, by generating new endothelial cells to build fresh endothelial linings in vivo (vascular regeneration, re-endothelialization of damaged blood vessels) and ex vivo (vessel engineering, re-endothelialization of stents). Embryonic stem cells (ESCs) were readily considered as excellent starting point, given their pluripotency (i.e. the capacity to form every single cell type of the body), stable karyotype, indefinite culturing yet fairly easy handling, and their intrinsic potential to recapitulate embryonic blood vessel development (vasculogenesis) . When using classical ESC culture conditions (i.e. embryoid body (EB) formation and the use of non-human serum and feeder layers), ESCs were indeed shown to be a proper cell source for endothelial regeneration . Various groups have subsequently optimized the efficiency to derive functional endothelial cells from ESCs in serum- and EB-free conditions, applicable for clinical scaling . However, apart from the risk of teratoma formation, the ethical issue of using ESCs in medicine remains a very difficult hurdle to overcome. One potential solution is the use of adult multipotent stem cells with endothelial plasticity, including MAPCs , cardiac stem cells , hematopoietic stem cells , etc., but their therapeutic efficiency for endothelial regeneration remains unclear and controversial. In addition, more committed adult vascular progenitor cells appear inefficient in regenerating vessels as they predominantly stimulate endogenous repair via paracrine pathways, thereby limited by the compromised conditions of the host (e.g. hypercholesterolemia, diabetes, obesity, ageing, etc.) .

Newly appreciated therapeutic effect of GLP-1 receptor agonists: Reduction in postprandial lipemia

Robert H.J. Bandsma, Gary F. Lewis — 2010-07-20

Atherosclerotic cardiovascular disease is one important consequence of the obesity pandemic that currently affects more than a billion people worldwide. Obesity is associated with insulin resistance, which in turn is associated with atherogenic dyslipidemia, of which postprandial hyperlipidemia is a major component. There is longstanding recognition that impaired clearance from the circulation of intestinally-derived lipoprotein particles and their lipid content contributes to postprandial hyperlipidemia in those with insulin resistance and type 2 diabetes mellitus (T2DM) . Dysregulation of intestinal lipoprotein secretion is a more recently recognized phenomenon that may also contribute to the dyslipidemia of those with insulin resistance and T2DM .

Sirt1 plays an important role in mediating greater functionality of human ES/iPS-derived vascular endothelial cells

2010-05-20

Abstract: Objective: We previously succeeded in inducing and isolating vascular endothelial cells (ECs) from both human embryonic stem (ES) and induced pluripotent stem (iPS) cells. Here, we compared the functionality of human adult ECs (HAECs), human ES-derived ECs (ESECs) and human iPS-derived ECs (iPSECs).Methods and results: We compared the cell proliferative potential, potential for migration, and tolerance to oxidative stress. ESECs were significantly superior to HAECs in all of these cell functions. The cell functions of iPSECs were comparable to those of ESECSs and also superior to HAECs. We then analyzed the gene expressions of HAECs, ESECs and iPSECs, and observed that the expression level of Sirt1, a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase, is higher in ESECs and iPSECs than in HAECs. The inhibition of Sirt1 with a Sirt1-specific inhibitor and siRNA antagonized these differences between the three types of cells.Conclusions: Sirt1 plays a key role in the high cellular function of ESECs and iPSECs. Although further in vivo investigations are required, this study initially demonstrated the potential of ESECs and iPSECs as the cell source for regenerative medicine, and also showed the potential of ES cells as a useful tool for elucidating the molecular mechanism of cell aging.

Atherosclerosis in Octodon degus (degu) as a model for human disease

2010-07-15

Abstract: Objective: Animal models of atherosclerosis are essential to elucidate disease mechanisms and develop new therapies. Each model features advantages and disadvantages in exemplifying the pathophysiology of human atherosclerosis. Diet-induced development of atherosclerosis in Octodon degus (degu) was examined to demonstrate the potential of the degu as a model of human atherosclerosis.Methods: Degus were fed for 16 weeks with either normal chow or chow containing 0.25% cholesterol and 6% palm oil to induce atherosclerosis. The lipid compositions of plasma lipoproteins and aortas were determined. Locations of aortic lesions were mapped by imaging of fluorescently stained aortic lesions. Lesion morphology in the brachiocephalic artery was detected by histological staining.Results: Total plasma cholesterol in chow-fed degus was distributed approximately 60% in HDL, 30% in LDL and less than 10% in VLDL. Cholesterol-fed degus exhibited 4- to 5-fold increases in total plasma cholesterol, principally in the VLDL and LDL fractions. Cholesteryl ester transfer protein activity of similar magnitude to that in human plasma was detected in chow-fed degu plasma. Cholesterol-fed degus developed cholesteryl ester-rich atherosclerotic lesions throughout the aorta. Histological examination of lesions in the brachiocephalic artery showed well-formed, foam cell-rich lesions populated with inflammatory cells. It is also noteworthy that all the degus in this study exhibited hyperglycemia.Conclusion: These results demonstrate that degus have a human-like lipoprotein metabolism and develop extensive atherosclerosis with cholesterol feeding in the presence of hyperglycemia. These features, combined with the manageable size and handling characteristics, point to the potential of the degu as a useful model for atherosclerosis research.

Heart rate reduction with ivabradine improves erectile dysfunction in parallel to decrease in atherosclerotic plaque load in ApoE-knockout mice

Magnus Baumhäkel, Florian Custodis, Nils Schlimmer, Ulrich Laufs, Michael Böhm — 2010-03-29

Abstract: Objective: To determine the effect of heart rate reduction with ivabradine on atherosclerotic lesions and erectile dysfunction.Methods: Two different treatment regimes with ivabradine were applied in wild-type (C57/B6) and ApoE−/−-mice to study effects of ivabradine on erectile function and atherosclerosis in animals with and without present endothelial dysfunction. Preventive effects of ivabradine were evaluated in animals fed a high-cholesterol diet in parallel to treatment with ivabradine (orally via chow, 10mg/kg per day). The other treatment regime started treatment with a high-cholesterol diet for 4 weeks to induce endothelial dysfunction. Thereafter, treatment with ivabradine (orally via chow, 15mg/kg per day) was started in ApoE−/− mice for 3 months. Vital parameters were measured using the tail-cuff method. Erectile function was assessed by pharmacological stimulation of corpora cavernosa in organ bath chambers. Atherosclerotic plaque formation, oxidative stress, eNOS and collagen content were determined.Results: Treatment with ivabradine significantly reduced heart rate (p<0.01), with no effect on blood pressure. Aortic atherosclerotic lesion size decreased with ivabradine in both treatment regimes (p<0.05). Endothelium-dependent relaxation of corpora cavernosa significantly decreased in ApoE−/−-mice with a restoration by ivabradine in prevention and reversal. Dihydroethidium-stained penile sections (p<0.05) and lipid peroxidase assay (p<0.05) revealed a reduction in superoxide production in ivabradine-treated animals. Penile eNOS-expression increased and collagen content significantly decreased (p<0.01) in ivabradine-treated animals.Conclusion: Ivabradine improves penile endothelial function by reduction of oxidative stress and penile fibrosis. Beneficial effects were achieved in prevention and manifest endothelial dysfunction.

Human umbilical cord blood endothelial progenitor cells decrease vein graft neointimal hyperplasia in SCID mice

2010-05-10

Abstract: Aims: Vein graft endothelial damage is a key step in the development of neointimal hyperplasia, leading to vein graft failure. We sought to determine whether exogenous endothelial progenitor cells could promote vein graft re-endothelialization, and thereby ameliorate neointimal hyperplasia.Methods and results: Carotid artery interposition grafting was performed with syngeneic inferior vena cavae in mice with severe combined immunodeficiency (SCID). Lineage-negative human umbilical cord blood (hUCB) cells (or medium alone) were injected into vein-grafted mice intra-operatively and 2 weeks post-operatively. In vein grafts from hUCB cell-injected mice, we found human HLA-expressing endothelial cells, as well as increased levels of VEGF and FGF-2. Furthermore, hUCB cells secreted VEGF and FGF-2 in vitro. The markedly enhanced endothelial regeneration, likely resulting from both direct engraftment and paracrine actions of hUCB cells, inhibited inflammatory response, diminished intimal cell proliferation, and reduced neointimal hyperplasia in the vein grafts.Conclusions: hUCB cells may accelerate vein graft re-endothelialization via both direct differentiation into endothelial cells and release of paracrine factors to enhance endothelial regeneration and reduce inflammation. These data highlight a potential therapeutic role for cellular therapy in vessel injury.

Chronic infusion of salusin-α and -β exerts opposite effects on atherosclerotic lesion development in apolipoprotein E-deficient mice

2010-05-31

Abstract: Objective: Human salusin-α and -β are two-related peptides processed from the same precursor, preprosalusin. Our previous in vitro studies have shown that human macrophage foam cell formation is stimulated by salusin-β but suppressed by salusin-α. Thus we investigated the effects of salusin-α and -β on atherosclerotic plaque formation in vivo in apolipoprotein E-deficient (ApoE−/−) mice.Methods: Saline (vehicle), salusin-α or -β (0.6nmol/kg/h) was continuously infused through osmotic mini-pumps into 13-week-old ApoE−/− mice for 8 weeks. Aortic atherosclerosis, oxidized LDL-induced cholesterol ester accumulation (foam cell formation), and its related gene expression in exudate peritoneal macrophages were determined.Results: After 4-week infusion of salusin-β, atherosclerotic lesions were 2.6 times greater than vehicle controls, which paralleled 1.9-fold increase in foam cell formation and up-regulation of scavenger receptors (CD36, scavenger receptor class A) and acyl-CoA: cholesterol acyltransferase-1 (ACAT1). In contrast, salusin-α decreased serum total cholesterol levels by 15% and foam cell formation by 68% associated with ACAT1 down-regulation. After 8-week infusion of salusin-α, atherosclerotic lesions were significantly suppressed by 54% compared with vehicle controls.Conclusions: Our study provided the first evidence that salusin-β accelerates the development of atherosclerotic lesions associated with up-regulation of scavenger receptors and ACAT1 in ApoE−/− mice. Whilst, salusin-α exerts anti-atherosclerotic effects by suppressing serum total cholesterol levels and ACAT1 expression.

Vascular superoxide production by endothelin-1 requires Src non-receptor protein tyrosine kinase and MAPK activation

2010-05-31

Abstract: ET-1 induces vascular O2− production via activation of NADPH oxidase. We have investigated whether c-Src and MAPKs activation are involved in ET-1-induced vascular oxidative response. At 2h, ET-1 induced an increase in NADPH oxidase-driven O2− production in rat isolated aortic rings, which was completely suppressed in PP2 (c-Src inhibitor)-pretreated rings, whereas PP3 (inactive analogue of PP2) was without effect. ET-1 increased the levels of phospho-c-Src, the active form of c-Src, and the phosphorylation of cortactin, a Src-specific substrate. Both c-Src and cortactin phosphorylation induced by ET-1 were prevented by PP2. The increased expression of p47phox, the main cytosolic subunit of NADPH oxidase, induced by ET-1 was also prevented by PP2. The increased vascular O2− production and p47phox up-regulation induced by ET-1 was only inhibited in aortic rings coincubated with the ERK1/2 inhibitor, PD98059; being without effects both the p38 MAPK inhibitor, SB203580, and JNK inhibitor, SP600125. Aortic rings incubation with ET-1 increased the phosphorylation of ERK1/2. This effect was suppressed by coincubation with PP2 showing that this event is down-stream of c-Src activation. In conclusion, ET-1 induces NADPH oxidase-driven O2− generation through increase of p47phox protein expression. The signalling pathway for this effect involves c-Src activation and ERK1/2 phosphorylation.

Pomegranate juice (PJ) consumption antioxidative properties on mouse macrophages, but not PJ beneficial effects on macrophage cholesterol and triglyceride metabolism, are mediated via PJ-induced stimulation of macrophage PON2

Mira Rosenblat, Nina Volkova, Michael Aviram — 2010-05-31

Abstract: Objective: To examine whether the beneficial effects of PJ consumption by mice on their macrophages are mediated via PJ-induced increment in serum paraoxonase 1 (PON1) activity and/or in macrophage PON2 expression.Methods and results: We performed studies in peritoneal macrophages (MPM) from C57BL/6 control mice, or from PON1KO mice, or from PON2KO mice that consumed PJ (200μg of gallic acid equivalents/mouse/day, for 1 month period).PJ consumption by C57BL/6 mice resulted in a significant increment, by 36% in serum PON1 catalytic activities, and upregulated MPM PON2 expression.In MPM from C57BL/6 or from PON1KO mice that consumed PJ, the extent of cell-mediated LDL oxidation was decreased by 22%, and that of cellular superoxide release by 20–26%. In contrast, PJ consumption by PON2KO mice resulted in a minimal inhibitory effect on macrophage oxidative stress by only 4–9%. Unlike PJ antioxidative effects in MPM, PJ anti-atherogenic effects on MPM cholesterol and triglyceride metabolism were similar in all mice groups that consumed PJ. After PJ consumption, cellular cholesterol content was decreased by 14–19%, and this could be attributed to a significant inhibition in MPM cholesterol biosynthesis rate by 20–32%, and/or to stimulation of HDL-mediated cholesterol efflux from the cells by 22–37%. Similarly, MPM triglyceride content and triglyceride biosynthesis rate were both significantly decreased after PJ consumption, by 16–27% and by 22–28%, respectively.Conclusion: PJ consumption antioxidative properties on mouse macrophages, but not PJ beneficial effects on macrophage cholesterol and triglyceride metabolism, are mediated via PJ-induced stimulation of macrophage PON2 expression. Serum PON1 stimulation by PJ consumption, however, was not involved in PJ-induced effects on macrophages.

Oats (Avena sativa) reduce atherogenesis in LDL-receptor-deficient mice

K.E. Andersson, K.A. Svedberg, M.W. Lindholm, R. Öste, P. Hellstrand — 2010-05-31

Abstract: Aim: The cholesterol-lowering properties of oats, largely ascribed to its contents of soluble fibers, beta-glucans, are well established, whereas effects on atherogenesis are less well elucidated. Oats also contains components with reported antioxidant and anti-inflammatory effects that may affect atherogenesis. In this work we examined effects of oat bran on plasma cholesterol, markers of inflammation, eNOS expression and development of atherosclerosis in LDL-receptor-deficient (LDLr−/−) mice.Methods and results: Female LDLr−/− mice were fed Western diet±oat bran. Two concentrations of oat bran (40 and 27%) were compared regarding effects on plasma lipids. There was a dose-dependent reduction of plasma cholesterol by 42 and 20% with 40 and 27% oat bran, respectively. Both concentrations also lowered plasma triglycerides (by 45 and 33%) and relative levels of plasma LDL+VLDL. The reduction of plasma lipids was accompanied by increased faecal excretion of cholesterol and bile acids. Oat bran (40%) efficiently reduced atherosclerotic lesion area in the descending aorta (−77%) and aortic root (−33%). Plasma levels of fibrinogen and soluble vascular cell adhesion molecule-1 (VCAM-1) were significantly lower, and immunofluorescence of aortic sections revealed a 75% lower expression of VCAM-1 in oat-fed mice. The expression of eNOS protein in the aortic wall was increased in mice fed oat bran.Conclusions: Oat bran supplemented to a Western diet lowers plasma cholesterol, reduces levels of some inflammatory markers, increases eNOS expression and inhibits atherosclerotic lesion development in LDLr−/− mice. It remains to be investigated which components in oats contribute to these effects.

The androgen derivative 5α-androstane-3β,17β-diol inhibits tumor necrosis factor α and lipopolysaccharide induced inflammatory response in human endothelial cells and in mice aorta

Giuseppe Danilo Norata, Paola Cattaneo, Angelo Poletti, Alberico Luigi Catapano — 2010-06-18

Abstract: Background: An increasing body of evidence suggests that testosterone may exert beneficial effects against the development of atherosclerosis. These effects are thought to be the consequence of its conversion into estradiol and the activation of the estrogen receptors; however a direct role of androgens, such as dihydrotestosterone, has also been proposed. More recently, it has been shown that the transformation of the dihydrotestosterone to 5α-androstane-3α,17β-diol (3α-diol) and 5α-androstane-3β,17β-diol (3β-Adiol), generates two molecules unable to bind the androgen receptor, but with a high affinity for the estrogen receptors (ERs) in particular the β isoform. As the actions of testosterone may result from the balance between androgenic and estrogenic molecules originating from its catabolism, we investigated the effects of the 3β-Adiol on inflammatory responses in vitro in human endothelial cells and ex vivo in mice aortas.Methods and results: 3β-Adiol reverts the pro-inflammatory gene expression pattern induced by TNF-α in HUVECs as determined by a cDNA microrray approach. Q-real-time PCR and protein array approaches confirmed that TNF-α-induced ICAM-1, VCAM-1 and ELAM-1 as well as MCP-1 and IL-6 induction was affected upon 3β-Adiol pre-incubation. ICI 182780, an estrogen receptor antagonist and R,R-THC, an estrogen receptor β antagonist, counteracted the effect of 3β-Adiol while bicalutamide, an androgen receptor antagonist, had minor effects. 3β-Adiol exerted a similar action on macrophages. Finally in castrated male mice, 3β-Adiol significantly counteracted the LPS mediated mRNA induction of IL-6, ELAM-1and PECAM-1 in the aortas.Conclusion: 3β-Adiol reverts in vitro the TNF-α and LPS induced pro-inflammatory activation of endothelial cells and macrophages. 3β-Adiol in vivo modulates the inflammatory response induced by LPS in the arterial vascular wall.

Dietary rice protein isolate attenuates atherosclerosis in apoE-deficient mice by upregulating antioxidant enzymes

2010-06-08

Abstract: Rice-based diets may have been reported to protect against the development of atherosclerosis; however, the underlying mechanism(s) for this protection remains unknown. In this report, the mechanism(s) contributing to the atheroprotective effects of rice-based diet was addressed using the apolipoprotein E knockout (apoE−/−) mice fed rice protein isolate (RPI) or casein (CAS). Reduced atherosclerotic lesions were observed in aortic sinus and enface analyses of the descending aorta in RPI-fed apoE−/− mice compared with CAS-fed mice. Plasma total- and HDL-cholesterol levels were not different amongst the two groups, suggesting alternative mechanism(s) could have contributed to the atheroprotective effect of rice-based diets. Plasma oxLDL and anti-oxLDL IgG levels were significantly decreased in RPI-fed compared to CAS-fed animals. Plasma and aortic tissue GSH levels and GSH:GSSG ratio were higher in RPI-fed mice compared to CAS-fed group. Interestingly, RPI feeding increased mRNA and protein expression of superoxide dismutase, and mRNA expression of catalase, glutathione peroxidase and glutathione reductase, key antioxidant enzymes implicated inhibiting oxidative stress leading to atherosclerosis. In conclusion, these findings suggest that the reduction in atherosclerotic lesions observed in mice fed the rice-based diet is mediated in part by inhibiting oxidative stress and subsequent oxLDL generation that could result in reduced foam cell formation, an early event during atherogenesis.

Effect of endothelial cell proliferation on atherogenesis: A role of p21Sdi/Cip/Waf1 in monocyte adhesion to endothelial cells

2010-07-05

Abstract: Objective: Uniform laminar shear stress (LS) and disturbed turbulent shear stress (DS) are thought to play opposite roles in preventing or inducing atherosclerosis. Endothelial cell (EC) growth and monocyte adhesion to ECs, an early event in atherosclerosis, are also oppositely regulated by LS and DS. However, how atherogenesis is affected by the regulation of growth by blood flow is unknown. Here we examined the role of p21Sdi/Cip/Waf1 (p21), a growth inhibitor induced by LS, in monocyte adhesion to ECs.Methods: p21 was overexpressed by transfecting a p21-expressing adenoviral vector into ECs. Factors linking EC growth, monocyte adhesion, and p21 were examined by microarray analysis, PCR and Western blotting.Results: Compared with DS, in the presence or absence of TNFα, LS significantly inhibited EC growth and monocyte adhesion to ECs. Both EC proliferation and monocyte adhesion induced by DS were inhibited by p21-overexpression. LS suppressed the expression of thioredoxin-interacting protein (TXNIP). Thioredoxin (TRX) activity, which is suppressed by TXNIP, was therefore higher under LS than DS, as reported previously. p21-overexpression significantly suppressed the DS-induced TXNIP expression, and inhibited the expression of vascular cell adhesion molecule 1 and chemokine (C–C motif) ligand 5 (CCL5/RANTES), which stimulates leukocyte recruitment and is downregulated by ROS scavenging.Conclusion: p21 may function to prevent atherogenesis by regulating the redox balance, which leads to the inhibition of adhesion molecule and chemokine expression in ECs under LS.

Reduction of PKCβII activity in smooth muscle cells attenuates acute arterial injury

Chun Huang, Jong Sun Chang, Yunlu Xu, Qing Li, Yu Shan Zou, Shi-Fang Yan — 2010-07-01

Abstract: Objective: The ubiquitous enzyme Protein Kinase C (PKC) has been linked to the pathogenesis of vascular injury, but the cell-specific and discrete functions of the βII isoform have yet to be discovered in this setting. Our previous findings demonstrated significantly increased PKCβII in the membrane fraction of injured femoral arteries in wild type (WT) mice and revealed reduction of neointimal expansion in PKCβ−/− mice after acute vascular injury. As PKCβ−/− mice are globally devoid of PKCβ, we established novel transgenic (Tg) mice to test the hypothesis that the action of PKCβII specifically in smooth muscle cells (SMCs) mediates the formation of neointimal lesions in response to arterial injury.Methods: Tg mice expressing SM22α promoter-targeted mouse carboxyl-terminal deletion mutant PKCβII were produced using standard techniques, subjected to femoral artery injury and compared with littermate controls. Smooth muscle cells (SMCs) were isolated from wild type (WT) and Tg mice and exposed to a prototypic stimulus, tumor necrosis factor (TNF)-α. Multiple strategies were employed in vivo and in vitro to examine the molecular mechanisms underlying the specific effects of SMC PKCβII in neointimal expansion.Results: In vivo and in vitro analyses demonstrated that PKCβII activity in SMCs was critical for neointimal expansion in response to arterial injury, at least in part via regulation of ERK1/2, Egr-1 and induction of MMP-9.Conclusions: These data identify the SMC-specific regulatory role of PKCβII in neointimal expansion in response to acute arterial injury, and suggest that targeted inactivation of PKCβII may be beneficial in limiting restenosis via suppression of the neointima-mediating effects of Egr-1 and MMP-9.

Beneficial direct adipotropic actions of pitavastatin in vitro and their manifestations in obese mice

2010-05-13

Abstract: Objective: Prevention of cardiovascular complications in obese patients frequently includes statin administration for coexisting dyslipidemia. Herein, we investigated the impacts of pitavastatin at clinically relevant doses on adipose dysfunction and insulin resistance.Methods: We treated 3T3-L1 preadipocytes with 10–100ng/ml pitavastatin from initiation of differentiation (Day 0) to Day 8 (differentiation/maturation phase) or from Day 8 to Day 16 (post-maturation phase). Subsequently, we administered pitavastatin (6.2mg/day/kg) to 7-week-old female KKAy mice for 6 weeks; untreated KKAy mice served as obese controls.Results: Pitavastatin impaired neither lipogenesis nor adiponectin expression during the differentiation/maturation phase. During the post-maturation phase, pitavastatin prevented excessive triglyceride accumulation, which was associated with attenuated glucose transporter-4 expression, and dose-dependently upregulated hormone-sensitive lipase expression. Decrements in the adiponectin/plasminogen activator-1 ratio were also dose-dependently inhibited. In KKAy mice, Coulter counter analyses revealed that pitavastatin treatment significantly decreased (by 16.8%) the frequency of hypertrophic adipocytes (>150μm in diameter) in parametrial adipose pads, of which total weight remained unaltered. Correspondingly, plasma adiponectin was significantly higher in pitavastatin-treated KKAy mice than in the untreated KKAy mice (12.5±3.8μg/ml vs. 8.3±1.5μg/ml, p<0.05). Moreover, the area under the time–glucose curve after intraperitoneal insulin was decreased by 16% in pitavastatin-treated KKAy mice (p<0.05 vs. untreated controls).Conclusions: Pitavastatin did not impair differentiation/maturation of preadipocytes and prevented their deterioration with hypertrophy after maturation at clinical concentrations in vitro. These effects likely contributed to improved insulin sensitivity, in an obese model, via prevention of adipocyte hypertrophy and adipocytokine dysregulation.

LXRα regulates human CETP expression in vitro and in transgenic mice

2010-05-24

Abstract: Liver X receptors (LXRs), LXRα and LXRβ, are members of the nuclear receptor superfamily and regulate the expression of genes involved in the regulation of cholesterol and fatty acid metabolism. Human plasma, unlike mouse plasma, contains cholesteryl ester transfer protein (CETP), which plays an important role in reverse cholesterol transport (RCT). LXRs induce CETP transcription via a direct repeat 4 element in the CETP promoter. However, the specific roles of the individual LXR subtypes in CETP expression and their consequences on plasma lipoprotein metabolism are still unclear. Here we showed that synthetic LXR agonist enhanced plasma CETP activity and resulted in non-high density lipoprotein (non-HDL) increase and HDL decrease in cynomolgus monkeys and human CETP transgenic mice. To address the relative importance of the two LXR subtypes, we investigated the effect of the suppression of both LXR subtypes on CETP expression in HepG2 cells. CETP expression induced by the LXR agonist was significantly reduced by LXRα knock-down, but not by LXRβ. Consistent with these data, CETP promoter activity was enhanced by LXRα activation, whereas LXRβ activation had only a minor effect. Furthermore, we investigated the effect of genetic deficiency of both LXR subtypes in human CETP transgenic mice. LXRα deficiency abolished the augmentation of plasma CETP activity and hepatic CETP expression induced by the synthetic LXR agonist, consequently increasing HDL and decreasing non-HDL, whereas LXRβ deficiency did not affect CETP activation. These findings indicate that LXRα has an essential role in the regulation of CETP expression and maintaining RCT.

Anti-atherogenic effect of BHB-TZD having inhibitory activities on cyclooxygenase and 5-lipoxygenase in hyperlipidemic mice

2010-05-31

Abstract: Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), which play pivotal roles in atherogenesis, have been reported to be involved in plaque stability. Licofelone, a dual COX and 5-LOX inhibitor, has been reported to possess anti-atherogenic effect in rabbit atherosclerosis model. We therefore investigated the anti-atherogenic effect of BHB-TZD [5-(3,5-di-tert-butyl-4-hydroxybenzylidene)thiazolidin-2,4-dione], a dual COX and 5-LOX inhibitor, in low density lipoprotein receptor null (LDLR−/−) mice. Fifteen LDLR−/− mice were fed a western diet (control group), whereas 15 were fed a western diet plus 0.1% (w/w) BHB-TZD (BHB-TZD group). After 8 weeks, the BHB-TZD group had markedly lower serum levels of leukotriene B4 and prostaglandin E2 than the control group. Interestingly, BHB-TZD treatment also reduced plasma triglyceride level without significant changes in total cholesterol and HDL levels. Compared with control mice, BHB-TZD fed mice had 52% fewer fatty streak lesions in the aortic sinus, as well as fewer initial lesions in the aortic arch. Macrophage infiltration into the lesions was 40% lower, and collagen and smooth muscle cells were increased by 102% and 96%, respectively, in the BHB-TZD group compared with the control group. In addition, aortic expression of proatherogenic molecules including TNF-α, IL-1β, IL-6, MCP-1 and VCAM-1, was lower in the BHB-TZD group than the control group. BHB-TZD treatment also reduced MMP-2 and MMP-9 expressions in aorta. In conclusion, BHB-TZD effectively attenuated atherosclerosis in mouse model, suggesting its therapeutic potential for atherosclerosis.

Specific binding of hypochlorite-oxidized HDL to platelet CD36 triggers proinflammatory and procoagulant effects

2010-05-31

Abstract: Objective: Oxidative stress and systemic inflammation negatively affect several protective functions of high density lipoproteins (HDL) and oxidative modification of HDL by the inflammation-derived oxidant hypochlorite converts HDL into a potent platelet agonist. Therefore it was the aim of this work to clarify if these platelet-activating effects result from specific binding of hypochlorite-oxidized HDL (hyp-OxHDL) to the platelet surface and to identify responsible receptors.Methods: Binding and functional studies were performed with hyp-OxHDL in absence and presence of (potential) competitors in normal and CD36-deficient human platelets.Platelet aggregation was quantified by light transmission aggregometry. Surface expression of CD62P, phosphatidylserine and CD40L was quantified by flow cytometry.Results: Binding studies reveal that hyp-OxHDL show specific and saturable high-affinity binding to the platelet surface. Hyp-OxHDL trigger platelet aggregation and in a dose dependent way provoke the release of significant amounts of CD40L as well as phosphatidylserine on the platelet surface. Blocking specific binding of hyp-OxHDL to the platelet surface interferes with the ability of hyp-OxHDL to stimulate human platelets.CD36-deficient human platelets show markedly reduced binding of hyp-OxHDL. Upon addition of hypochlorite-oxidized HDL, CD36-deficient platelets do not aggregate and completely fail to release CD40L or phosphatidylserine.Conclusions: From these results we conclude that specific binding of hyp-OxHDL to platelet CD36 is essential for the proinflammatory and procoagulant effects of hyp-OxHDL shown within this work. The contribution of other receptors besides CD36 to specific binding of hyp-OxHDL to the platelet membrane appears to be minimal, at best.

Enhanced matrix-degrading proteolytic activity within the thin thrombus-covered wall of human abdominal aortic aneurysms

2010-05-31

Abstract: Objective: The maintenance of an arterial elastin's integrity is essential in the prevention of abdominal aortic aneurysm (AAA) development. So far, the effect of intraluminal thrombus (ILT) thickness on the elastolytic activity within the AAA wall has not been studied. In the present study the hypothesis that thin thrombus is associated with enhanced proteolytic activity within human AAA wall was investigated.Methods: The specimens for analysis, from both thin (≤10mm) thrombus-covered and thick (≥25mm) thrombus-covered wall, had been taken from 40 patients undergoing elective repair of AAA. We evaluated neutrophil elastase activity with the enzymatic assay. Concentrations of active matrix metalloproteinase-9 (MMP-9), total matrix metalloproteinase-8 (MMP-8), and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) were measured by ELISA. Biochemical parameters were compared with the Wilcoxon signed-rank test.Results: Statistical analysis showed that the activity of elastase (P<0.0001) as well as concentrations of active MMP-9 (P=0.001), total MMP-8 (P<0.0001) and active MMP-9/total TIMP-1 ratio (P=0.002) were significantly higher in the thin thrombus-covered wall. Furthermore the TIMP-1 was found to have a lower concentration in the thin thrombus-covered in comparison with the thick thrombus-covered wall (P=0.003). There was a significant positive correlation between measurements in AAA wall sites with thin and thick thrombus for elastase, TIMP-1, MMP-9/TIMP-1 ratio, and a borderline correlation was observed for MMP-8. Active MMP-9 concentration did not correlate between sites.Conclusion: The current study demonstrates the differentiation of protease activity within the same AAA wall and its enhancement within the thin thrombus-covered aneurysm wall.

The aorta wall of patients presenting to the emergency department with acute myocardial infarction by cardiac magnetic resonance

2010-06-28

Abstract: Background: Inflammation has been shown to be a major component in the pathophysiology of acute coronary syndrome (ACS). In patients presenting with acute myocardial infarction (AMI), a critical component of the ACS spectrum, multiple coronary arteries are involved during this inflammatory process. In addition to the coronary vasculature, the inflammatory cascade has also been shown to affect the carotid arteries and possibly the aorta.Purpose: To assess the involvement of the aorta during AMI by cardiac magnetic resonance (CMR).Methods: We prospectively evaluated the aortic wall by CMR in 123 patients. 78 patients were enrolled from the emergency department (ED), who presented with chest pain and were classified as either: (1) AMI: elevated troponin levels and typical chest pain or (2) non-cardiac chest pain (CP): negative troponins and a normal stress test or normal cardiac catheterization. We compared these 2 groups to a group of 45 asymptomatic diabetic patients. The descending thoracic aortic wall area (AWA) and maximal aortic wall thickness (AWT) were measured using a double inversion recovery T-2 weighted, ECG-gated, spin echo sequence by CMR.Results: Patients with AMI were older, more likely to smoke, had a higher incidence of claudication, and had higher CRP levels. The AWA and maximal AWT were greater in patients who presented to the ED with ACS (2.11±0.17mm2, and 3.17±0.19mm, respectively) than both patients presenting with non-cardiac CP (1.52±0.58mm2, p<0.001; and 2.57±0.10mm, p<0.001) and the diabetic patients (1.38±0.58mm2, p<0.001; and 2.30±0.131mm, p<0.001). The difference in the aortic wall characteristics remained significant after correcting for body mass index, hyperlipidemia, statins and C-reactive protein. There was no difference in maximal AWT or AWA between patients with non-cardiac CP and patients with diabetes.Conclusion: Patients with AMI have a significantly greater maximal aortic wall thickness and area compared to patients with non-cardiac CP. Longitudinal studies are needed to assess whether this increase is due to inflammation or a higher atherosclerotic burden.

Association of monocyte subsets with vulnerability characteristics of coronary plaques as assessed by 64-slice multidetector computed tomography in patients with stable angina pectoris

2010-05-31

Abstract: Objective: The aim of the present study was to examine the relation between monocyte subsets and the presence, extent, and vulnerability characteristics of non-calcified coronary plaques (NCPs) as assessed by multidetector computed tomography (MDCT).Methods: We studied 73 patients with stable angina pectoris who underwent MDCT. Two monocyte subsets (CD14+CD16− and CD14+CD16+) were measured by flow cytometry. Coronary artery plaques were assessed by 64-slice MDCT. We defined NCP vulnerability according to the presence of positive remodeling (remodeling index>1.05) and/or low CT attenuation plaques (<35HU).Results: A total of 40 (55%) patients had identifiable vulnerable plaques. The relative proportion of CD14+CD16+ monocytes was significantly greater in patients with 1 or multiple vulnerable plaques than in patients with no vulnerable plaques or control (healthy) subjects. In addition, the relative proportion of CD14+CD16+ monocytes was positively correlated with remodeling index (r=0.40, P<0.01) and negatively correlated with CT attenuation value (r=−0.34, P<0.01).Conclusion: The present results suggest that an increased subset of CD14+CD16+ monocytes is related to coronary plaque vulnerability in patients with stable angina pectoris.

Carotid distension and distensibility impairment in individuals affected by familial combined hyperlipidemia

Tiziana Montalcini, Gaetano Gorgone, Carmine Gazzaruso, Arturo Pujia — 2010-06-09

Abstract: Objective: To investigate whether individuals affected by familial combined hyperlipidemia, a common lipid disorder increasing the cardiovascular risk, had different carotid ultrasound parameters compared to control subjects without this family disorders.Methods: 127 cases and 127 controls matched for age and gender were enrolled. Serum glucose, total cholesterol, high-density lipoprotein-cholesterol, triglycerides, ApoB, insulinemia were measured by standard laboratory techniques. All the subjects underwent B-mode ultrasonography to measure the end-diastolic and end-systolic diameter of the common carotid artery and, successively, to calculate distensibility, compliance, Young's elastic modulus and distension.Results: Carotid diameter and Young's elastic modulus were significantly greater among FCH subjects than among controls, and carotid distensibility, compliance, distension and score distension were significantly lower than control, also after analysis of covariance in order to adjust all the carotid indexes for confounding variables. A multiple regression analysis confirmed that familial combined hyperlipidemia status was correlated to carotid indexes. In a model including the lipid parameters, triglycerides was the only lipid variable correlated with distensibility but not with distension.Conclusion: This hyperlipidemia, particularly hypertrigliceridemia, could be the direct responsibility of carotid modification leading to the impairment of the distension/distensibility that, in turn, makes the patients prone to atherosclerosis.

In vivo optical molecular imaging of matrix metalloproteinase activity in abdominal aortic aneurysms correlates with treatment effects on growth rate

Rahul A. Sheth, Marco Maricevich, Umar Mahmood — 2010-06-14

Abstract: Objectives: We present a method to quantify the inflammatory processes that drive abdominal aortic aneurysm (AAA) development that may help predict the rate of growth and thus guide medical and surgical management. We use an in vivo optical molecular imaging approach to quantify protease activity within the walls of AAAs in a rodent model.Methods: AAAs were generated in mice by topical application of calcium chloride, followed by the administration of the MMP inhibitor doxycycline for 3 months. After this time period, an enzyme-activatable optical molecular imaging agent sensitive to MMP activity was administered, and MMP proteolytic activity was measured in vivo. Histology and in situ zymography were performed for validation. AAAs were also generated in rats, and MMP activity within the walls of the AAAs was also quantified endovascularly.Results: A dose-dependent response of AAA growth rate to doxycycline administration was demonstrated, with high doses of the drug resulting in nearly complete suppression of aneurysm formation. There was a direct relationship between the rate of aneurysmal growth and measured MMP activity, with a linear best-fit well approximating the relationship. We additionally performed endovascular imaging of AAAs in rats and demonstrated a similar suppression of intramural MMP activity following doxycycline administration.Conclusions: We present an in vivo evaluation of MMP activity within the walls of AAAs in rodents and show a direct, linear relationship between proteolytic activity and aneurysmal growth. We also illustrate that this functional imaging method can be performed endovascularly, demonstrating potential pre-clinical and clinical applications.

Passive leg raising induced brachial artery dilation: Is an old technique a simpler method to measure endothelial function?

2010-06-18

Abstract: Objectives: Passive leg raising (PLR) is a diagnostic maneuver that has been shown to cause brachial artery dilation (BAD). The objectives of this study were to compare BAD induced by PLR with flow mediated dilation (FMD), and to investigate the mechanism of PLR-BAD. We studied a total of 75 subjects with and without cardiovascular risk factors/disease in order to provide a wide range of FMD responses.Methods: Using ultrasound, PLR-BAD and FMD induced by release of arterial cuff occlusion were measured.Results: BA diameter increased from 0.33+0.06 at baseline to 0.35±0.06cm (p<.001) (4.8% increase) upon PLR and from 0.33±0.06 to 0.37±0.06 (11.8%) upon hyperemia. PLR induced BAD was significantly correlated with FMD (r=.82, p<.001). On receiver operating characteristic analysis of the two techniques, the area under the curve was 0.86 (95% CI 0.79–0.94, p<.001). Heart rate variability measures remained unchanged upon PLR indicating minimal contributions from changes in autonomic activity. The combination of FMD and PLR did not result in greater BAD than did FMD alone consistent with a common underlying mechanism. Mean blood flow velocity increased prior to BAD suggesting that shear stress increases prior to BAD.Conclusions: BAD occurs in response to PLR and is proportional to FMD, although the magnitude of PLR-BAD is less than half that of FMD. It appears to occur by the same endothelial dependent mechanism as FMD. PLR-BAD may be used as a surrogate measure of FMD to evaluate vascular function, and has the advantage of being simpler to perform.

Single variants can explain the association between coronary heart disease and haplotypes in the apolipoprotein(a) locus

2010-06-02

Abstract: Objective: LPA encodes apolipoprotein(a), and a CCTC haplotype in the LPA locus is associated with CHD. The 4399Met variant (rs3798220) of LPA has a risk estimate for CHD similar to that of the CCTC haplotype. We asked whether co-incidence with the 4399Met variant explained the association of the haplotype with CHD.Methods: We stratified by the 4399Met variant and another LPA SNP (rs10455872) associated with CHD and tested the association between CHD and 4 SNPs that define two haplotypes associated with CHD: CCTC and CTTG.Results: For CCTC, in the presence of the rs3798220 risk allele the OR was 1.68 (95% CI: 1.05–2.68, P=0.03) versus 0.30 (95% CI: 0.06–1.59, P=0.16) with the non-risk allele. For CTTG, in the presence of the rs10455872 risk allele the OR was 1.57 (95% CI: 1.15–2.13, P=0.004) versus 1.04 (95% CI: 0.79–1.35, P=0.77) with the non-risk allele.Conclusion: The rs3798220 and rs10455872 SNPs explain the association of the CCTC and CTTG haplotypes with CHD.

Silencing of the F11R gene reveals a role for F11R/JAM-A in the migration of inflamed vascular smooth muscle cells and in atherosclerosis

2010-06-07

Abstract: Rationale and objective: Our previous studies have determined that the F11 receptor (F11R; aka JAM-A) exerts a critical force in the adhesion of human platelets to inflamed endothelial cells (ECs), and thus can play a significant role in the initiation of atherosclerotic plaque formation. In the present study, we focus on a subsequent event in plaque development – the migration of smooth muscle cells (SMCs) from the media to the intima of inflamed vessels. Here we report our investigation of the expression of F11R in atherosclerotic arteries of coronary artery disease (CAD) patients, and of the role of F11R in the migration of SMCs involved in atherogenesis.Methods and results: Histological staining and specific-antibody immunofluorescence of excised, human atherosclerotic coronary arteries revealed the expression of F11R in the SMCs of the intima. RT-PCR and SDS-PAGE followed by immunoblotting procedures demonstrated that F11R mRNA and the F11R protein levels were enhanced by the stimulation of cultured human aortic SMCs with a combined treatment of proinflammatory cytokines (TNFα+INFγ+IL-β1). Neither the F11R message nor protein was expressed in non-stimulated SMCs. The functional role of F11R in SMCs’ migration was studied in cytokine-stimulated SMCs by interference of F11R expression with siRNA. Silencing of the F11R gene of cytokines-treated SMCs inhibited the expression of both F11R mRNA and F11R protein. Functionally, silencing of the F11R gene blocked the proliferation and migration of these inflamed SMCs, both critical events in atherogenesis.Conclusions: The new findings of this study are that F11R mRNA and F11R protein are expressed in SMCs of the intima (but not in the media) of atherosclerotic arteries of CAD patients, and that F11R is required for the proliferation and migration of inflamed SMCs. Based on these findings, we conclude that in addition to the previously reported role of F11R in the initiation of plaque formation, F11R plays also an important role in the subsequent growth of atherosclerotic plaques. Identification of drugs that interfere with these pathophysiologic actions of F11R thus represents an effective new approach for the prevention and treatment of atherosclerosis, heart attacks and stroke.

Angiotensin II induces C-reactive protein expression through ERK1/2 and JNK signaling in human aortic endothelial cells

Chunjie Han, Juntian Liu, Xiaofang Liu, Ming Li — 2010-06-10

Abstract: Background: Atherosclerosis is an inflammatory disease in the vessel. As an inflammatory cytokine, C-reactive protein (CRP) participates in atherogenesis. Although angiotensin II (AngII) is known to evoke inflammatory response in vascular endothelial cells (VECs), there is no direct evidence to demonstrate the proinflammatory effect of AngII on VECs through CRP. The present study focused on effect of AngII on CRP expression and the signal pathway in human aortic endothelial cells (HAECs).Methods and results: mRNA and protein expression was identified by RT-PCR and Western blot, respectively. Reactive oxygen species (ROS) were observed by a fluorescence microscope. The results showed that AngII significantly increased mRNA and protein expression of CRP in HAECs in time- and concentration-dependent ways. Anti-IL-1β and anti-IL-6 neutralizing antibodies did not affect AngII-induced CRP expression. Losartan reduced AngII-induced CRP expression in mRNA and protein levels in HAECs. Losartan and TIFA decreased AngII-stimulated ROS generation, and antioxidant NAC completely abolished AngII-induced CRP expression in HAECs. The further study indicated that losartan, NAC, PD98059, SP600125 significantly inhibited ERK1/2 and JNK phosphorylation, and PD98059, SP600125, PDTC completely antagonized AngII-induced CRP expression in HAECs.Conclusions: The present study demonstrates that AngII has ability to induce CRP expression in HAECs through AT1-ROS-ERK1/2 and JNK-NF-κB signal pathway, which strengthens understanding of the proinflammatory and proathroscerotic actions of AngII.

Association between aldehyde dehydrogenase 2 genetic polymorphism and serum lipids or lipoproteins: A meta-analysis of seven East Asian populations

2010-06-14

Moderate alcohol consumption appears to confer some protection against coronary heart disease, which is related to changes in serum levels of lipoproteins, especially high-density lipoprotein cholesterol (HDL-C) . Mitochondrial aldehyde dehydrogenase 2 (ALDH2) metabolizes acetaldehyde produced from ethanol into acetate and plays a crucial role in the oxidation of acetaldehyde in vivo . A sequence variant (rs671) on chromosome 12q24.2 was found associated with inactive ALDH2. A mutant allele, ALDH2*2, has a single point mutation (G to A transition in exon 12) at position 1510 of the active ALDH2*1 gene, which results in a substitution of glutamic acid 504 to lysine and produces inactive ALDH2 . The Glu504Lys variant is almost exclusively present in East Asians, and Wada et al. found no variants of rs671 in a Caucasian population. The ALDH2 genotypes are closely related to alcohol metabolism and were recently found to be associated with atherosclerosis , hypertension , and myocardial infarction in Asians. The risks have been attributed primarily to an increase in serum HDL-C level. Recently, we reported an association of ALDH2 deficiency and increased risk of type II diabetes mellitus in female patients with coronary artery disease but not levels of serum lipids and/or lipoproteins or coronary atherosclerosis severity . The reason for the discrepancy is unclear but may be related to low statistical power or to differences among the ethnic groups studied.

Exenatide suppresses postprandial elevations in lipids and lipoproteins in individuals with impaired glucose tolerance and recent onset type 2 diabetes mellitus

2010-06-17

Abstract: Objective: Chronic exenatide treatment in type 2 diabetes is associated with improved glucose control and fasting lipid levels, as well as weight loss. Less established is whether exenatide directly reduces postprandial lipid and lipoprotein levels without the reduction in body weight or fasting glucose and triglycerides levels that frequently occur with prolonged therapy. Therefore, the effect of a single injection of exenatide on postprandial lipids, remnant lipoproteins, and apolipoproteins was studied.Methods: A double-blinded, randomized, placebo-controlled, crossover study was conducted in 35 subjects (31 men and 4 women) with impaired glucose tolerance (n=20) or recent onset type 2 diabetes (n=15). A single subcutaneous injection of exenatide (10μg) or normal saline was administered just prior to a high-calorie, fat-enriched breakfast meal. Concentrations of triglycerides (TG), apolipoproteins B-48 and CIII, non-esterified fatty acids (NEFA), and remnant lipoprotein (RLP) cholesterol and TG in serum or plasma were measured prior to the injection and for up to 8h postprandially.Results: Exenatide markedly reduced postprandial elevation of TG, apolipoproteins B-48 and CIII, RLP-cholesterol and RLP-triglyceride (all p<0.001). Postprandial declines in NEFA were less pronounced but persisted longer with exenatide compared to placebo (p<0.05). These effects of exenatide were not affected either by glucose tolerance status or by treatment with statins.Conclusion: These results demonstrate that exenatide acutely and profoundly inhibits postprandial excursions of proatherogenic lipids and lipoproteins and may offer additional cardiovascular risk reduction (NCT00974272).

One-year treatment with exenatide vs. Insulin Glargine: Effects on postprandial glycemia, lipid profiles, and oxidative stress

2010-05-24

Abstract: Objective: The objective of the present study was to investigate the effects of one-year treatment with exenatide or Insulin Glargine, followed by a 5-week off-drug period, on postprandial lipidaemia, glycaemia and measures of oxidative stress.Methods: Sixty-nine metformin-treated patients with type 2 diabetes were randomised (using apermuted block randomisation scheme stratified by site and baseline HbA1c stratum (≤8.5% or >8.5%) of which 60 completed (exenatide n=30; Insulin Glargine n=30) the pre-treatment and on-drug meal test. Postprandial glucose, lipids and lipoproteins, and oxidative stress markers were studied at week −1, 51, and after a 5-week off-drug period following a breakfast and lunch mixed-meal containing 50g fat, 75g carbohydrates, and 35g protein.Results: 51-Week exenatide treatment resulted in a significant reduction of prandial glucose, triglycerides, apo-B48, calculated VLDL-C, FFA and MDA excursions whereas Insulin Glargine predominantly reduced fasting glucose, FFA and MDA. Changes in markers of oxidative stress were related to changes in postprandial glucose and triglyceride excursions, independent of treatment arm. All postprandial measures returned to pre-treatment values in both groups after 5-week cessation of study treatment.Conclusion: Exenatide showed beneficial effects on postprandial glycaemia and lipidaemia, and these effects were related to changes in the oxidative stress markers MDA and oxLDL during one year of treatment as compared to Insulin Glargine. Following cessation of both exenatide and Insulin Glargine measures returned to pre-treatment values, suggesting that ongoing treatment is necessary to maintain the beneficial effects of either therapy.

Exercise training accelerates the removal from plasma of LDL-like nanoemulsion in moderately hypercholesterolemic subjects

2010-06-07

Abstract: Objective: Exercise training improves plasma lipid profile and diminishes risk of coronary heart disease. Previously, we showed that training increases LDL plasma clearance, as tested by an artificial LDL-like nanoemulsion method, presumably by increasing LDL receptor activity. In this study, we investigated whether training could also improve LDL clearance in hypercholesterolemic subjects (HCh) that are exposed to increased risk of cardiovascular events.Methods: Twenty sedentary HCh and 20 normolipidemic (NL) sedentary volunteers were divided into four groups: 12 HCh submitted to 4-month training program, 8 HCh with no exercise program, 12 NL submitted to 4-month training and 8 NL with no exercise program. An LDL-like nanoemulsion labeled with 14C-cholesteryl ester was injected intravenously into all subjects and plasma samples were collected during 24h after injection to determine the fractional clearance rate (FCR, in h−1) by compartmental analysis. The study was performed on the first and on the last day of the 4-month study period.Results: In both, trained HCh and NL groups, training increased nanoemulsion FCR by 36% (0.0443±0.0126; 0.0602±0.0187, p=0.0187 and 0.0503±0.0203; 0.0686±0.0216, p=0.0827, respectively). After training, LDL cholesterol diminished in both HCh and NL groups. In HCh, but not in NL group, LDL susceptibility to oxidation decreased, but oxidized LDL was unchanged. In both non-trained groups FCR was the same for the last and the 4-month previous evaluation.Conclusion: In HCh, exercise training increased the removal of LDL as tested by the nanoemulsion, and this probably accounted for decreased LDL cholesterol and diminished LDL susceptibility to oxidation.

Correlation between circulating adiponectin levels and coronary plaque regression during aggressive lipid-lowering therapy in patients with acute coronary syndrome: Subgroup analysis of JAPAN-ACS study

2010-05-31

Abstract: Objective: The Japan assessment of pitavastatin and atorvastatin in acute coronary syndrome (JAPAN-ACS) study demonstrated that aggressive lipid-lowering therapy with a statin resulted in a significant regression of coronary atherosclerotic plaques in patients with ACS. Adiponectin is an adipocyte-derived protein with anti-atherogenic properties. Here, we investigated the association between adiponectin levels and the change in the plaque volume in ACS patients.Methods: Intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) was undertaken, followed by the initiation of statin treatment, in 238 patients with ACS. Follow-up IVUS was performed between 8 and 12 months after the PCI. The percent change in the plaque volume (%PV) in a non-culprit coronary artery segment was evaluated. The serum adiponectin and lipid parameters were measured both at baseline and at the follow-up.Results: At baseline, adiponectin was correlated positively with HDL-cholesterol and negatively correlated with triglyceride, but no correlation was observed with the PV. Adiponectin levels increased significantly from 7.8±4.6μg/mL at baseline to 10.3±6.9μg/mL at the 8–12 months follow-up. The increase in adiponectin was also associated with an increase of HDL-cholesterol and decrease of triglyceride, however, no significant correlation was observed with the %PV. A significantly higher incidence of major adverse cardiac events (MACE) was observed in patients with hypo-adiponectinemia at baseline. A multiple logistic regression analysis identified adiponectin as a significant independent predictor of MACE.Conclusion: Adiponectin levels measured after PCI could serve as a marker of MACE in patients with ACS.

Three-month treatment with pioglitazone reduces circulating levels of thiobarbituric acid-reacting substances, a marker of reactive oxidative stress, without change in body mass index, in Japanese patients with type 2 diabetes

2010-06-14

Patients with type 2 diabetes (T2DM) are at substantially higher risk of mortality, primarily from cardiovascular disease, than the general population . The PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) remains the only large-scale, prospective, secondary prevention trial carried out entirely in patients with T2DM . This trial provides information of a possible macrovascular benefit with pioglitazone (PGZ), peroxisome proliferators-activated receptor-γ (PPAR-γ) agonists, thiazolidinedione (TZD), particularly in terms of major adverse cardiovascular events, despite only showing a statistical trend towards benefit for the primary composite outcome. However, the driver of the favorable effects of PGZ is still unknown. We previously demonstrated that the favorable effects of PGZ on glucose metabolism are associated with an increase in the circulating fat-derived hormone adiponectin , possessing an array of antidiabetogenic and cardiovascular protective effects. As well as reducing hyperglycemia, PGZ increases insulin sensitivity and also exerts additional pleiotropic effects on the chronic inflammation and endothelial dysfunction that underlie atherosclerosis . Oxidative stress, induced by intracellular accumulation of reactive oxygen species (ROS), is also causally related to endothelial dysfunction, atherosclerosis, diabetic vasculopathies and beta cell failure in T2DM . Our study showed that the adipose tissue is the major source of ROS (FatROS), and thus related to the pathophysiology of obesity . In rodents, TZD can eliminate oxidative stress both in vitro and in vivo . In the present study, we investigated the effect of treatment with PGZ on circulating thiobarbituric acid-reacting substances (TBARS), markers for systemic ROS production, and adiponectin levels in T2DM patients.

Plasma PCSK9 is increased by Fenofibrate and Atorvastatin in a non-additive fashion in diabetic patients

2010-07-12

Abstract: Objective: Proprotein convertase subtilisin kexin/type 9 (PCSK9) is an inhibitor of the low density (LDL) lipoprotein receptor. Plasma PCSK9 is increased by Fenofibrate and statins. Here, we determined how standard dose of statin and combined therapy with Fenofibrate modulate PCSK9.Methods: Randomized, open-label cross-over study investigating the effect of Fenofibrate (160mg), Atorvastatin (10mg), and combination of both in patients with type 2 diabetes mellitus and atherogenic dyslipidemia. After the single administration of Atorvastatin and Fenofibrate for 6 weeks, patients received both for another 6 weeks. PCSK9, lipids and lipoproteins levels were determined at day 1, weeks 6, 9 and 12.Results: Upon 6 weeks of treatment, Atorvastatin decreased LDL-cholesterol by 30% (p<0.001) and Fenofibrate decreased triglyceride level by 31% (p<0.01) and increased HDL-cholesterol by 13% (p<0.05). Combination did not show further benefit. Atorvastatin increased PCSK9 by 24% at day 1 and by 14% at week 6 (p≤0.01). Fenofibrate increased PCSK9 by 26% at week 6 (p≤0.01), but had no effect at day 1. Three weeks of combination therapy increased PCSK9 by 42%, 6 weeks by 19% (p≤0.01). PCSK9 changes were not different between treatments over 6-week periods.Conclusion: Fenofibrate and Atorvastatin increased circulating PCSK9 in diabetic patients, with no additive effect after 6 weeks of combined therapy.

Eicosapentaenoic acid (EPA) from highly concentrated n−3 fatty acid ethyl esters is incorporated into advanced atherosclerotic plaques and higher plaque EPA is associated with decreased plaque inflammation and increased stability

2010-06-09

Abstract: Objective: To examine n−3 polyunsaturated fatty acid (PUFA) incorporation into atherosclerotic plaques and the association with plaque inflammation and stability.Methods and results: Patients awaiting carotid endarterectomy (n=121) were randomised to consume control capsules or n−3 PUFA ethyl ester capsules until surgery (median 21 days). The fatty acid compositions of plasma and carotid plaque phospholipids, plaque features, and expression of inflammatory genes were determined. The proportion of eicosapentaenoic acid (EPA) was higher (P<0.0001) in carotid plaque phospholipids in patients in the n−3 PUFA group. Plaques from patients in the n−3 PUFA group had fewer foam cells (P=0.0390). There were no other differences between plaques in the two groups with regard to histological characteristics or morphology. Plaque stability was not different between the two groups. However, the EPA content of plaque phospholipids was inversely associated with plaque instability (P=0.0209), plaque inflammation (P=0.0108), the number of T cells in the plaque (P=0.0097) and a summary score considering a range of plaque features (P=0.0425). Plaques from patients who received n−3 PUFAs had significantly lower levels of mRNA for matrix metalloproteinases (MMP)-7 (P=0.0055), -9 (P=0.0048) and -12 (P=0.0044) and for interleukin-6 (P=0.0395) and intercellular adhesion molecule 1 (P=0.0142).Conclusions: Atherosclerotic plaques readily incorporate EPA. A higher plaque EPA content is associated with a reduced number of foam cells and T cells, less inflammation and increased stability.

Associations between dietary patterns and flow cytometry-measured biomarkers of inflammation and cellular activation in the Atherosclerosis Risk in Communities (ARIC) Carotid Artery MRI Study

2010-06-01

Abstract: Background: Specific foods and overall dietary patterns are associated with soluble biomarkers of systemic inflammation and endothelial activation. However, no large epidemiological studies have evaluated relationships between such dietary factors and cell-specific markers of activation and inflammation as measured by flow cytometry.Methods: Cell aggregates and multiple platelet and leukocyte markers were quantified by flow cytometry in fresh whole blood from 1101 white adults participating in the Carotid Artery MRI Study, a subset of the larger Atherosclerosis Risk in Communities (ARIC) Study. Two dietary patterns (“Healthy” and “Western”) were empirically derived via principal components analysis using data collected by food frequency questionnaire. Cross-sectional associations between dietary patterns and flow cytometry-measured biomarkers were evaluated, adjusting for demographics and lifestyle factors, including medications use.Results: After multivariable adjustment, monocyte lipopolysaccharide receptor (CD14), monocyte toll-like receptor-2, and platelet glycoprotein IIb (CD41) showed inverse associations with the Healthy dietary pattern (p=0.01, 0.04, and 0.01, respectively). In contrast, the Western dietary pattern was positively associated with CD41 and platelet–granulocyte aggregates (p=0.01 and 0.04, respectively). Independent of other dietary factors, alcohol consumption was inversely associated with levels of pan-leukocyte marker (CD45), P-selectin (CD62P) on PLA1 and on PLA2 platelets, and platelet–monocyte, platelet–granulocyte, and platelet–lymphocyte aggregates.Conclusion: Dietary patterns and alcohol intake were each cross-sectionally associated with select markers of cellular activation and inflammation measured by flow cytometry. These data are consistent with the hypothesis that holistic measures of dietary intake are associated with inflammation.

Cysteinemia, rather than homocysteinemia, is associated with plasma apolipoprotein A-I levels in hyperhomocysteinemia: Lipid metabolism in cystathionine β-synthase deficiency

2010-05-31

Abstract: Objective: Genetic and dietary hyperhomocysteinemia has been found to decrease high density lipoproteins (HDL) and their apolipoprotein A1 (APOA1). To test the hypothesis that the presence of cysteine could normalize HDL levels in hyperhomocysteinemic cystathionine β-synthase (Cbs)-deficient mice and that the inclusion of glycine would block this effect.Methods: Lipids and HDL cholesterol were studied in Cbs-deficient mice and wild-type animals fed a low-methionine diet supplemented with cysteine and glycine and in Cbs-deficient mice on the same diet supplemented only with cysteine.Results: Triglyceride and homocysteine levels were significantly decreased and increased, respectively in Cbs-deficient mice irrespective of treatment. However, plasma cholesterol, glucose and APOA1 were significantly decreased in homozygous Cbs-deficient mice when they received the cysteine and glycine-enriched beverage. This group of mice also showed decreased mRNA levels and increased hepatic content of APOA1 protein, the latter increase was observed in endothelial cells. A significant, inverse relationship was observed between plasma and hepatic APOA1 concentrations while a positive one was found between plasma levels of cysteine and APOA1.Conclusion: These data suggest an altered hepatic management of APOA1 and that cysteine may be involved in the control of this apolipoprotein at this level. Overall these findings represent a new aspect of dietary regulation of HDL at the hepatic transendothelial transport.

Increased visceral adipose tissue mass is associated with increased C-reactive protein in patients with manifest vascular diseases

Daniël R. Faber, Yolanda van der Graaf, Jan Westerink, Frank L.J. Visseren — 2010-05-24

Abstract: Background: Obesity is related to the development of vascular diseases and metabolic complications. Low grade inflammation is a key feature of central obesity, characterized by elevated plasma levels of C-reactive protein (CRP). We hypothesize that visceral adipose tissue contributes to systemic concentrations of CRP.Methods: In 2410 patients (1729 men and 681 women) with vascular diseases, subcutaneous and visceral fat masses were analyzed with ultrasonography. Metabolic parameters and CRP were measured in a fasting state. The association between fat measurements and plasma CRP was quantified using linear regression analysis. CRP levels were logarithmically transformed. Adjustments were made for age, smoking, type 2 diabetes mellitus, insulin resistance (HOMA-IR) and medication use.Results: Visceral fat was categorized into quartiles (Q) ranging from 3.2 to 7.8cm in Q1 (reference) to 11.0–19.8cm in Q4 in men and 2.7–6.0cm in Q1 (reference) to 9.0–17.4cm in Q4 in women. β-coefficients gradually increased across the quartiles from 0.07 (0.01–0.13) in Q2 to 0.25 (0.19–0.31) in Q4 in men and 0.17 (0.07–0.26) in Q2 to 0.42 (0.32–0.52) in Q4 in women, indicating 0.25 and 0.42mg/l higher logarithmically transformed (log)CRP levels in Q4 compared to Q1 in respectively men and women. Per standard deviation increase of visceral fat, logCRP levels increased with 0.10mg/l (0.07–0.12) in men and with 0.11 (0.15–0.19) in women. Likewise, in separate analyses waist circumference and body mass index showed a positive, but weaker association with logCRP levels across quartiles (in men: β 0.21 (0.15–0.27) in Q4 for waist circumference and β 0.23 (0.17–0.30) in Q4 for body mass index; in women: β 0.32 (0.22–0.42) in Q4 for waist circumference and β 0.32 (0.22–0.42) in Q4 for body mass index). In men subcutaneous fat was not associated with logCRP (β-coefficients relative to Q1: −0.01 (−0.07 to −0.05), −0.01 (−0.07 to −0.05) and 0.05 (−0.01 to −0.11) in Q2 to Q4 respectively).Conclusions: In conclusion, visceral fat thickness is the strongest contributor to the systemic CRP concentrations in patients with vascular diseases.

Alcohol consumption and risk of recurrent cardiovascular events and mortality in patients with clinically manifest vascular disease and diabetes mellitus: The Second Manifestations of ARTerial (SMART) disease study

2010-05-31

Abstract: Objective: This study investigated the relation between alcohol consumption and specific vascular events and mortality in a high risk population of patients with clinical manifestations of vascular disease and diabetes.Methods: Patients with clinically manifest vascular disease or diabetes (n=5447) from the SMART study were followed for cardiovascular events and mortality. Alcohol consumption was assessed with a baseline questionnaire and analysed in relation with coronary heart disease (CHD), amputations, stroke, and all-cause and vascular death.Results: After a follow up of 4.7 years, we documented 363 cases of CHD, 187 cases of stroke, 79 amputations and 641 cases of all-cause death, of which 382 were vascular. In multivariate-adjusted models, alcohol consumption was inversely associated with CHD (plinear trend=0.007) and stroke (plinear trend=0.051) with respective hazard ratios of 0.39 (95%CI: 0.20–0.76) and 0.67 (0.31–1.46) for consuming 10–20 drinks/week compared with abstainers. We observed significant U-shaped associations between alcohol consumption and amputations (pquadratic trend=0.001), all-cause death (pquadratic trend=0.001) and vascular death (pquadratic trend=0.013). Hazard ratios for consuming 10–20 drinks/week were 0.29 (0.07–1.30) for amputations, 0.40 (0.24–0.69) for all-cause death and 0.34 (0.16–0.71) for vascular death compared with abstainers. Similar associations were observed for red wine consumption only.Conclusion: Moderate alcohol consumption (1–2 drinks/day) is not only associated with a reduced risk of vascular and all-cause death in a high risk patients with clinical manifestations of vascular disease, but also with reduced risks of non-fatal events like CHD, stroke and possibly amputations.

Usefulness of the triglyceride to high-density lipoprotein cholesterol ratio for predicting mortality risk in type 2 diabetes: Role of kidney dysfunction

2010-06-01

Abstract: Objective: An increased level of triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio has been identified as an independent predictor for cardiovascular events in the general population and in some groups of high-risk patients, such as type 2 diabetes. The aim of this study was to evaluate whether a high TG/HDL-C ratio is associated with an increased risk of all-cause and cardiovascular mortality in type 2 diabetic subjects, and whether this risk is modified by the presence of kidney dysfunction.Methods: We followed 3084 type 2 diabetic outpatients for a mean period of 4.9 years for the occurrence of mortality. The independent association between the TG/HDL-C ratio and all-cause and cardiovascular mortality was analyzed by Cox proportional hazard models and adjusted for several potential confounders, including kidney function measures.Results: During follow-up, 356 (12%) participants died, 46% of whom from cardiovascular causes. Higher TG/HDL-C ratio (third vs. first tertile) was associated with an increased hazard ratio of all-cause (hazard ratio 1.51, CI 95% 1.13–2.00, p=0.005) and cardiovascular (hazard ratio 1.70, 1.12–2.59, p=0.015) mortality after adjustment for traditional risk factors, body mass index, hemoglobin A1c and medication use. After additional adjustment for renal function measures (estimated glomerular filtration rate or albuminuria), the association between the TG/HDL-C ratio and the risk of mortality was abolished.Conclusion: Our findings suggest that the predictive role of a high TG/HDL-C ratio in type 2 diabetes on cardiovascular and all-cause mortality might be largely mediated by the presence of kidney dysfunction.

Autonomic nervous system, inflammation and preclinical carotid atherosclerosis in depressed subjects with coronary risk factors

2010-06-01

Abstract: Objectives: We investigated the relationship between intima-media thickening (IMT) as an expression of preclinical atherosclerosis and coronary risk factors, including the autonomic nervous system and inflammation markers, in depressed subjects free from coronary artery disease.Methods: We studied 391 asymptomatic subjects with a cluster of risk factors, and we evaluated depression using the Beck Depression Inventory. IMT of the common carotid artery was determined by B-mode ultrasound imaging. Traditional risk factors for atherosclerosis were recorded. Markers of inflammation (C-reactive protein, CRP; interleukin 6, IL-6) and heart rate variability (time domain) were determined.Results: A total of 90 (23.0%) subjects showed a depressive symptomatology. The average IMT was increased in depressed subjects (0.87±0.35mm) at risk for CHD but free from disease as compared to controls (0.77±0.19mm; p<0.001). Heart rate variability was reduced in depressed subjects. Levels of SDNN (103±14ms) and SDANN (93±20ms) were decreased in depressed subjects as compared to non-depressed subjects (SDNN 113±22ms and SDANN 108±35ms; p<0.001). Subjects with depression had higher CRP (1.14±0.65mg/dl) and IL-6 (2.00±0.40pg/ml) than subjects without depression (CRP: 0.79±0.34mg/dl; IL-6: 1.6±0.6pg/ml; p<0.001, respectively). In multivariate analysis, depression was positively correlated with CRP and IL-6 and IMT, and inversely associated with levels of SDANN.Conclusions: IMT is higher in depressed subjects, indicating that atherosclerosis is accelerated in this sub-group of patients. This is mainly due to patho-physiological mechanisms which connect depression and coronary artery disease, such as inflammation and imbalance of the autonomic nervous system.

Effects of low serum triglyceride on stroke mortality: A prospective follow-up study

Wi-Sun Ryu, Seung-Hoon Lee, Chi Kyung Kim, Beom Joon Kim, Byung-Woo Yoon — 2010-06-03

Abstract: Background: Low serum triglyceride (TG) has been suggested as a predictor of mortality after cardiovascular disease. However, the relationship between the level of TGs and the outcome after stroke remains to be elucidated. We hypothesized that the influence of TG levels on post-stroke mortality varies according to stroke mechanism: cardioembolic (CE) vs. non-CE causes.Methods: We prospectively enrolled a consecutive series of patients with first-ever acute ischemic stroke for 5 years (n=1067), and followed them until the end of 2007 to obtain information on mortality and cause of death. We divided the level of TG into the quartiles, and classified the patients into CE (n=226) and non-CE stroke groups (n=841). The influence of TG level on mortality (all-cause death and vascular death) was examined by univariate and multivariate analyses using Cox regression.Result: All-cause death and vascular death rates showed inverse relationships to the quartiles of TG levels in all patients (p<0.001, both) and also in non-CE stroke group (p<0.001, both), but not in CE stroke group (p=0.17 and p=0.37, respectively). In the Cox-regression analysis, compared with the highest quartile, the adjusted hazard ratio (HR) of the lowest quartile for all-cause death was 2.58 [95% confidence interval (CI), 1.38–4.82] and that for vascular death was 3.50 (95% CI, 1.39–8.82) in non-CE stroke group. These same associations, however, were not significant in CE stroke group.Conclusion: Our results indicate that low serum TG is an independent predictor of mortality after ischemic stroke brought on by non-CE causes.

Subclinical peripheral arterial disease in rheumatoid arthritis

2010-05-31

Abstract: Objective: Rheumatoid arthritis (RA) is associated with accelerated atherosclerosis in the carotid arteries, but little is known about the magnitude of this process in peripheral arteries. Assessing preclinical atherosclerosis in both arterial beds in RA might provide additional prognostic value during risk stratification for primary prevention. Therefore in the present structural study we examined femoral versus carotid subclinical atherosclerosis in RA and controls.Methods: Intima-media thickness (IMT) and atheromatous plaque presence and vulnerability in femoral versus carotid arteries were examined in 80 RA patients without overt cardiovascular disease or diabetes and 80 controls matched 1:1 for age, gender and traditional cardiovascular disease risk factors.Results: Femoral IMT and plaque prevalence were increased in RA than controls (p=0.001 and 0.008, respectively). These increases remained significant after adjustment for potentially confounding factors that differed between groups, such as C-reactive protein and HDL-cholesterol serum levels, and statin use. Femoral plaque vulnerability did not differ between RA and controls. The presence of RA was found to be an independent predictor of increased femoral IMT (p=0.004), after adjustment for traditional cardiovascular risk factors, C-reactive protein and treatment with angiotensin converting enzyme inhibitors and statins. Femoral plaques were less frequent than carotid plaques in RA patients (22.5% vs 45.0% respectively, p=0.003) and in contrast to carotid plaques were independent of age and glucose levels.Conclusions: Subclinical peripheral atherosclerosis in RA is more advanced than in controls. Prospective studies are required to confirm that RA is an independent risk factor for peripheral arterial disease.

Dehydroepiandrosterone sulfate is inversely associated with sex-dependent diverse carotid atherosclerosis regardless of endothelial function

2010-06-03

Abstract: Background: Dehydroepiandrosterone sulfate (DHEAS) is thought to be associated with life expectancy and anti-aging. However, its biological significance in atherosclerosis remains controversial. Therefore, the aim of this study was to determine whether DHEAS is associated with development of carotid atherosclerosis in subjects with cardiovascular risk factors.Subjects and methods: A total of 419 Japanese individuals (208 males and 211 females) were recruited from Tokushima University Hospital, Japan. In all subjects, maximum intima–media thickness (max-IMT) in all carotid arteries, and mean-IMT and mean blood flow volume (BFV) in the common carotid arteries (CCA) were measured by ultrasonography; endothelial function was assessed by flow-mediated vasodilation of the brachial artery (%FMD). Serum DHEAS and classical cardiovascular risk factors were also evaluated. Statistical significance was determined by multiple regression analysis to elucidate independent determinants of max-IMT, mean-IMT, mean CCA-BFV, and %FMD.Results: Serum DHEAS levels were higher in males than in females. Multiple regression analysis revealed that DHEAS was an independent negative factor for both max-IMT and mean-IMT in males but not in females. In contrast, DHEAS was the sole positive factor for mean CCA-BFV in females but not in males. In addition, there was no significant relationship between %FMD and DHEAS regardless of sex and other confounding factors.Conclusion: Although DHEAS is not involved in endothelial function, DHEAS is inversely associated with sex-dependent diverse carotid atherosclerosis such as increased max-IMT and mean-IMT in males and decreased CCA-BFV in females.

Occult impaired glucose regulation in patients with atherosclerosis is associated to the number of affected vascular districts and inflammation

2010-06-16

Abstract: Objective: The role of inflammatory adipokines has clear mechanistic effects in the promotion of both DM2 and cardiovascular diseases (CVDs), but it is unknown to what extent atherosclerosis-related inflammation might promote defects of glucose metabolism. The purpose of this study was to test the hypothesis that in subjects with atherosclerotic vascular disease and no previous medical record of type 2 diabetes mellitus (DM2), the diagnosis of occult impaired glucose regulation (IGR) is related to the severity of atherosclerosis, measured as the single or combined presence of an history of coronary artery disease (CAD), carotid atherosclerosis (Car-ATS) and peripheral artery disease (PAD).Methods: In a population of 551 subjects (440 men and 111 women) with a previous history of atherosclerosis, we investigated the presence of IGR (including both impaired glucose tolerance and DM2). To test the correlation between conventional and non-conventional risk factors for cardiovascular disease and diabetes we used logistic and regression analysis models.Results: IGR was more prevalent in patients with a documented vascular disease in two or three vessel districts compared with patients with only one symptomatic district (p=0.016). Among classic risk factors we found that waist circumference was correlated neither to IGR nor to symptomatic vascular disease extension. By contrast, adiponectin level was independently associated to vascular and glucose regulation status (p=0.012 and p<0.001, respectively).Conclusion: In subjects affected by atherosclerotic vascular diseases, the presence of impaired glucose regulation is associated to the number of vascular districts affected and to a reduced adiponectin level.

Helicobacter pylori cytotoxin-associated gene-A antibodies do not predict complications or death in type 2 diabetes: The Fremantle Diabetes Study

2010-06-09

Arterial stiffness is associated with low thigh muscle mass in middle-aged to elderly men

2010-06-16

Abstract: Objective: Sarcopenia of legs is an important cause of physical dysfunctions, frailty and dependence. Many predisposing and underlying mechanisms of sarcopenia, including age, sedentary life style, oxidative stress, insulin resistance, and low testosterone levels, are also known to be related to atherosclerosis, which is another leading cause of morbidity and mortality in elderly subjects. In this study, we investigated our hypothesis that sarcopenia and atherosclerosis are associated with each other to facilitate mutual abnormalities.Methods: Study was performed in apparently healthy 496 middle-aged to elderly persons recruited consecutively among the visitors to the medical check-up program, Anti-Aging Doc, in a University hospital, from March 2006 to December 2007. Mid-thigh muscle cross-sectional area (CSA) was measured by computed tomography and corrected by body weight (CSA/BW). Carotid intima–media thickness (IMT) and brachial–ankle pulse wave velocity (baPWV) were measured.Results: Thigh muscle CSA/BW was significantly and negatively associated with carotid IMT and baPWV in men but not in women. After correction for other confounding parameters, baPWV was an independent risk for the presence of sarcopenia in men (odds ratio of 1m/s increase of baPWV=1.14, 95% CI=1.01–1.30, p<0.05) in addition to age, body height, low physical activity, free testosterone level. Conversely, thigh muscle CSA/BW was an independent determinant of baPWV (β=−0.15, p<0.01) in addition to age, blood pressure, triglyceride, and antihypertensive drug use in men.Conclusions: Arterial stiffness is related to thigh muscle volume in men. Sarcopenia and atherosclerosis may share a common pathway and interact with each other to facilitate mutual abnormalities.

Increased levels of thioredoxin in patients with abdominal aortic aneurysms (AAAs). A potential link of oxidative stress with AAA evolution

2010-07-08

Abstract: Objective: Oxidative stress is a main mechanism involved in vascular pathologies. Increased thioredoxin (TRX) levels have been observed in several oxidative stress-associated cardiovascular diseases. We aim to test the potential role of TRX as a biomarker of oxidative stress in abdominal aortic aneurysm (AAA).Methods: TRX levels were analysed in both AAA intraluminal thrombus (ILT) tissue and in tissue-conditioned media by immunohistochemistry, Western blot and ELISA. Moreover, serum TRX levels were assessed in AAA Caucasian patients by ELISA.Results: TRX was mainly localized in the luminal part of ILT in AAA. Compared with the abluminal layer, TRX release was increased in the luminal layer of the ILT of AAA (31±9ng/ml vs. 9±3ng/ml, p<0.05). The interest of this approach is that we can identify proteins potentially released into the blood compartment, which could serve as biomarkers of the pathology. In a training population, serum TRX levels were significantly increased in patients with AAA relative to healthy subjects (50±6ng/ml vs. 26±3ng/ml, p<0.05). These results were validated in a second independent group of patients. Moreover, a positive correlation between TRX and AAA size (rho=0.5, p<0.001) was observed. Finally, in AAA samples with follow-up, TRX was positively associated to aneurismal growth rate (rho=0.25, p=0.027).Conclusions: TRX release is increased in the luminal part of AAA and TRX serum levels are increased in AAA patients compared with healthy subjects. TRX levels correlates with AAA size and expansion, suggesting its potential role as a biomarker of AAA evolution.

Acute effects of whey protein isolate on cardiovascular risk factors in overweight, post-menopausal women

Sebely Pal, Vanessa Ellis, Suleen Ho — 2010-06-21

Abstract: Objective: The purpose of this study was to investigate the acute effects of dietary whey proteins on lipids, glucose and insulin, and resting energy expenditure in overweight and obese post-menopausal women, a population highly susceptible to cardiovascular disease.Methods: A three-way crossover design study was conducted where 20 overweight or obese, post-menopausal women were randomised to consume either 45g whey protein isolate, 45g sodium caseinate or 45g of a glucose control in conjunction with a breakfast meal. Blood samples were taken for up to 6h.Results: There was no significant change in postprandial incremental area under the curve (AUC) for total cholesterol, low density lipoprotein, high density lipoprotein, non-esterified fatty acids, Apo B48, insulin and leptin between groups. However, there was a significant decrease in the appearance of triglycerides (TG) in the blood by 21% and 27% after consuming the whey meal compared to control and casein meals, respectively, as measured by AUC. There was also a significant reduction by 27% and 32% in the AUC for TG:ApoB48 ratio in the whey group compared to the glucose and casein groups, respectively. There was a significantly lower AUC for blood glucose after the consumption of the whey and casein meal compared to glucose meal.Conclusion: These findings suggest that a single dose of whey protein can decrease arterial exposure to smaller TG-enriched lipoprotein particles compared to the glucose and casein meals in the postprandial period in overweight and obese, post-menopausal women.

Arterial stiffness and declines in individuals with normal renal function/early chronic kidney disease

2010-07-01

Abstract: Objective: We evaluated the temporal association between arterial stiffening and the early stage of renal functional decline.Methods: In 2053 Japanese employees with an estimated glomerular filtration rate (GFR) of ≥60ml/min/1.73m2 plus no proteinuria (40±8 years old) at the start, brachial-ankle pulse wave velocity (baPWV) and serum C-reactive protein (CRP) were measured before and after a 5–6-year follow-up period.Results: After adjusting for confounding variables including serum CRP levels, higher baseline baPWV was associated with lower follow-up GFR (value expressed as per doubling: −16; 95% confidence interval: −24 to −9; P<0.01) and with higher annual rate of decline in GFR (value expressed as per doubling: −3; 95% confidence interval: −4 to −2; P<0.01). Every m/s higher baPWV was associated with a 36% increased odds (95% CI 1.09–1.70; P<0.01) for a development of a GFR <60ml/min/1.73m2 at follow-up. In contrast, baseline GFR was not associated with follow-up baPWV (P=0.08) or the annual rate of change in baPWV (P=0.11).Conclusion: In a Japanese occupational cohort with normal renal function/early chronic kidney disease, elevated arterial stiffness was an independent risk factor for the decline in renal function. CRP did not appear to exert any significant influence on this association.

Decreased serum levels of thioredoxin in patients with coronary artery disease plus hyperhomocysteinemia is strongly associated with the disease severity

Yunfei Wu, Lijuan Yang, Liangwei Zhong — 2010-07-01

Abstract: Objective: Elevation of homocysteine and thioredoxin (Trx) levels was found in some patients with coronary artery diseases (CAD). However, their correlations with CAD were not clear. Dysfunction of thioredoxin/thioredoxin reductase (TrxR) may cause oxidative stress that is common to CAD. We seek to determine the association among homocysteine, Trx/TrxR and CAD.Methods: Serum samples were collected from 150 CAD patients under statin treatment and 122 non-CAD controls. Risk factors for atherosclerosis including homocysteine, lipids and glucose levels were analyzed. Trx/TrxR activities and protein levels were determined using super-insulin assay and Western blot, respectively. One-way ANOVA, Tukey's post hoc test and Spearman's rank correlation coefficient were used for statistical analysis. CAD severity was evaluated by angiographic Gensini score.Results: Compared with non-CAD group, CAD group had significantly increased TrxR activity (P<0.05) and homocysteine levels (P<0.01), but not Trx activity. After further dividing CAD group using homocysteine below 15μM as reference, Trx activity decreased significantly in CAD group with high homocysteine, and was inversely associated with homocysteine levels (r=−0.199, P<0.05) that was, however, weakly positively associated with TrxR activity. Neither lipids nor glucose significantly affected Trx/TrxR activity. Association of CAD severity with low Trx plus high homocysteine was strong (r=−0.458, P<0.001), but with high homocysteine alone was rather weak (r=0.125, P=0.225).Conclusion: In CAD patients, high homocysteine levels may cause low Trx activity, which is closely correlated to the extent and severity of CAD.