Advertisement

Effective high-density lipoprotein cholesterol is associated with carotid intima-media thickness and vascular events after acute ischemic stroke

      Highlights

      • Higher effective HDL-C′ is indepedently associated with decreased carotid intima-media thickness.
      • Higher effective HDL-C′ is indepedently associated with a reduced risk for incident major adverse cardiovascular events.
      • Effective HDL-C′ outperforms traditional HDL-C in predicting MACE.

      Abstract

      Background and aims

      Effective high density lipoprotein cholesterol (HDL-C) is a measure of HDL functionality. We evaluated if HDL-C is associated with carotid intima-media thickness (cIMT) and incident major adverse cardiovascular events (MACE) in patients with acute ischemic stroke from two prospective cohort studies.

      Methods

      In the MARK-STROKE cohort, 299 patients with acute ischemic stroke or TIA were included. Outcome was available in 219 patients during a median follow-up of 294 days. In CIRCULAS, 382 acute ischemic stroke patients were included and a 90-day follow-up was available in 213 patients. HDL-C was calculated based on symmetric dimethylarginine (SDMA) and HDL cholesterol concentrations. Main outcome was incident MACE (death, stroke, and myocardial infarction) and the main measure was cIMT.

      Results

      In both studies, HDL-C was inversely associated with cIMT in linear regression analysis adjusted for age, sex and creatinine. In MARK-STROKE, the adjusted hazard for MACE was significantly reduced for patients with one unit increase (mg/dL) of HDL-C (hazard ratio 0.95 [95% confidence interval (CI): 0.92, 0.99]). In the CIRCULAS cohort, stroke patients with higher HDL-C had less incident MACE during 90 days of follow-up (odds ratio: 0.97 [95% CI: 0.94, 0.99] for one unit increase). Neither SDMA nor HDL cholesterol predicted outcome.

      Conclusions

      Our findings imply a protective role of biologically effective HDL after acute cerebral ischemia for secondary events and emphasize the relevance of lipoprotein functionality in these patients.

      Graphical abstract

      Keywords

      1. Introduction

      High-density lipoproteins (HDL) confer anti-thrombotic, anti-arteriosclerotic and anti-inflammatory effects in the vasculature. Recent studies have emphasized the importance of HDL functionality compared with absolute concentrations. [
      • Rohatgi A.
      • Westerterp M.
      • von Eckardstein A.
      • Remaley A.
      • Rye K.A.
      HDL in the 21st century: a multifunctional roadmap for future HDL research.
      ] Besides cholesterol efflux, anti-oxidative and anti-inflammatory properties of HDL confer endothelial-protective effects. However, dysfunctional HDL found in patients with diabetes, metabolic syndrome or chronic kidney disease can cause endothelial injury promoting atherosclerotic processes. [
      • Sorrentino S.A.
      • Besler C.
      • Rohrer L.
      • et al.
      Endothelial-vasoprotective effects of high-density lipoprotein are impaired in patients with type 2 diabetes mellitus but are improved after extended-release niacin therapy.
      ,
      • Speer T.
      • Rohrer L.
      • Blyszczuk P.
      • et al.
      Abnormal high-density lipoprotein induces endothelial dysfunction via activation of Toll-like receptor-2.
      ] A hallmark of endothelial dysfunction is the impairment of vasoprotective nitric oxide (NO), which can be aggravated by endogenous inhibitors of NO metabolism. [
      • Schwedhelm E.
      • Boger R.H.
      The role of asymmetric and symmetric dimethylarginines in renal disease.
      ] Among these endogenous metabolites involved, symmetric dimethylarginine (SDMA) can transform the physiological anti-arteriosclerotic HDL into dysfunctional pro-arteriosclerotic lipoproteins inhibiting endothelial NO production. [
      • Speer T.
      • Rohrer L.
      • Blyszczuk P.
      • et al.
      Abnormal high-density lipoprotein induces endothelial dysfunction via activation of Toll-like receptor-2.
      ] Based on these studies, an algorithm was proposed, which allowed the calculation of biologically effective HDL cholesterol (HDL-C). [
      • Speer T.
      • Rohrer L.
      • Blyszczuk P.
      • et al.
      Abnormal high-density lipoprotein induces endothelial dysfunction via activation of Toll-like receptor-2.
      ] More importantly, these findings translate into clinical outcome. Higher HDL-C was associated with a reduced all-cause and cardiovascular mortality in patients with low SDMA levels, whereas mortality was increased with higher HDL-C in patients with high SDMA. [
      • Zewinger S.
      • Kleber M.E.
      • Rohrer L.
      • et al.
      Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease.
      ] Interestingly, calculated HDL-C concentrations revealed a better risk discrimination than HDL cholesterol. [
      • Zewinger S.
      • Kleber M.E.
      • Rohrer L.
      • et al.
      Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease.
      ] Although HDL-C predicted all-cause and cardiovascular mortality in two cardiovascular cohorts, i.e. LURIC and MONICA/KORA S3,5 its role in patients with stroke remains unclear. So far, low HDL cholesterol is known to predict stroke recurrence, [
      • Zhang F.
      • Liu L.
      • Zhang C.
      • Ji S.
      • Mei Z.
      • Li T.
      Association of metabolic syndrome and its components with risk of stroke recurrence and mortality: a meta-analysis.
      ] but does not reflect HDL functionality appropriately. Here, we hypothesized that reduced HDL-C as parameter of HDL functionality is associated with vascular risk and outcome after stroke in two independent cohorts.

      2. Patients and methods

      2.1 Study design, ethical approval and patient consent in MARK-STROKE

      The bioMARKers in STROKE (MARK-STROKE) cohort is an on-going prospective observational single-center study at the University Medical Center Hamburg-Eppendorf as previously described. [
      • Schwedhelm E.
      • von Lucadou M.
      • Peine S.
      • et al.
      Trimethyllysine, vascular risk factors and outcome in acute ischemic stroke (MARK-STROKE).
      ] The inclusion criteria were age ≥18 years and diagnosis of stroke or transient ischemic attack at discharge. For this exploratory cohort study, patients recruited between November 2017 and December 2019 without available HDL cholesterol or SDMA values were excluded. Furthermore, the algorithm to calculate biologically effective HDL cholesterol is only valid for SDMA concentrations ≥0.48 μmol/l. Therefore, all patients with SDMA levels <0.48 μmol/l were excluded and cross-sectional analyses were calculated for 299 patients (Supplemental Fig. 1). From December 2019 until March 2020, patients were followed up by phone or mail. For 219 patients, we recorded major cardiovascular events (i.e. death, myocardial infarction, stroke). The study protocol was approved by the Ethics Committee of the Hamburg Board of Physicians (PV4715). The investigation was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants.

      2.2 Study design, ethical approval and patient consent in CIRCULAS

      The inclusion criteria for this exploratory cohort study were age ≥18 years and diagnosis of stroke at discharge. Patients without available HDL cholesterol or SDMA values and with SDMA levels <0.48 μmol/l were excluded. Three-month follow-up was conducted in person or by phone. Written informed consent was obtained from all subjects. The investigation was conducted in accordance with the Declaration of Helsinki.

      2.3 Clinical assessment

      Neurological deficits were assessed by the National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at admission. Demographic parameters, past medical history, including comorbidities (arterial hypertension, hyperlipidemia, diabetes mellitus, atrial fibrillation, prior stroke, prior myocardial infarction), laboratory (creatine kinase (CK), creatinine, C-reactive protein (CRP), triglycerides, total cholesterol, low density lipoprotein (LDL) cholesterol and HDL cholesterol and imaging data (infarct type, internal carotid artery (ICA) stenosis, and carotid intima-media thickness (cIMT)) were obtained from medical records.

      2.4 Carotid intima-media thickness

      In MARK-STROKE, the greatest cIMT measured in the right and left common carotid artery was used to define individual cIMT, as described previously. [
      • Rosenkranz M.
      • Russjan A.
      • Goebell E.
      • et al.
      Carotid plaque surface irregularity predicts cerebral embolism during carotid artery stenting.
      ,
      • Touboul P.J.
      • Hennerici M.G.
      • Meairs S.
      • et al.
      Mannheim carotid intima-media thickness and plaque consensus (2004-2006-2011). An update on behalf of the advisory board of the 3rd, 4th and 5th watching the risk symposia, at the 13th, 15th and 20th European Stroke Conferences, Mannheim, Germany, 2004, Brussels, Belgium, 2006, and Hamburg, Germany, 2011.
      ] In CIRCULAS, the average cIMT was measured in the right and left common carotid artery, as described elsewhere. [
      • Sharma K.
      • Blaha M.J.
      • Blumenthal R.S.
      • Musunuru K.
      Clinical and research applications of carotid intima-media thickness.
      ]

      2.5 Laboratory measurements

      Laboratory measurements were performed from serum and EDTA plasma samples collected at admission as described elsewhere. [
      • Choe C.U.
      • Atzler D.
      • Wild P.S.
      • et al.
      Homoarginine levels are regulated by L-arginine:glycine amidinotransferase and affect stroke outcome: results from human and murine studies.
      ,
      • Tiedt S.
      • Brandmaier S.
      • Kollmeier H.
      • et al.
      Circulating metabolites differentiate acute ischemic stroke from stroke mimics.
      ] SDMA was quantified by liquid chromatography-tandem mass spectrometry from EDTA plasma samples as previously described. [
      • Schwedhelm E.
      Quantification of ADMA: analytical approaches.
      ] In brief, 25 μL of EDTA plasma was diluted in methanol with stable isotope labeled internal standard on 96-well plates. After protein precipitation, analytes were converted into butyl esters derivatives and analysed with calibrators and quality controls (QC) by liquid chromatography-tandem mass spectrometry. SDMA concentrations were calculated using calibration curves based on four levels in triplicates. Plate wise QC were run in two levels by triplicates. Coefficients of variation and bias of QC were below 15%. HDL-C was calculated using the following equation: HDL-C = (1.869 Ln(SDMA)+(0.227–1.054⋅ Ln(SDMA))⋅ √HDL cholesterol +1.372) [
      • Sorrentino S.A.
      • Besler C.
      • Rohrer L.
      • et al.
      Endothelial-vasoprotective effects of high-density lipoprotein are impaired in patients with type 2 diabetes mellitus but are improved after extended-release niacin therapy.
      ].

      2.6 Statistical analysis

      Relationships between HDL cholesterol, SDMA and HDL-C with continuous variables were assessed with Spearman's correlation or linear regression analyses (beta coefficient and 95% confidence interval, CI). For regression analysis, we calculated beta coefficients or odds ratios (ORs) for different models: unadjusted (model 1), adjusted for age, sex and GFR (model 2), and adjusted for age, sex, GFR, LDL cholesterol, prevalent arterial hypertension, prevalent diabetes, prevalent hypercholesterolemia (model 3). Time-to-event analysis for HDL-C and MACE was assessed with Kaplan-Meier survival analyses and log rank test. The associations between one unit increase in HDL cholesterol (mg/dL), SDMA (μmol/L) and HDL-C (mg/dL) or biomarker levels above the median with incident MACE were determined by Cox regression analyses with results presented as hazard ratio (HR) with corresponding 95% CI. For Cox regression, we calculated HRs for different models: unadjusted (model 1), adjusted for age, sex, GFR (model 2), and adjusted for age, sex, GFR, LDL cholesterol, prevalent arterial hypertension, prevalent diabetes, and prevalent hypercholesterolemia (model 3). A p value < 0.05 was considered statistically significant. Due to the exploratory design of our study, we did not adjust for multiple comparisons. Statistical analysis was performed with IBM SPSS Statistics (version 27, IBM Corp., Armonk, NY, USA) and GraphPad Prism (version 9 for Windows, La Jolla, USA).

      2.7 Validation in the circulating biomarkers in acute stroke (CIRCULAS) study

      All measurements and analyses were performed similarly compared with the MARK-stroke cohort. Of note, in the CIRCULAS study, plasma samples from acute stroke patients were collected upon admission within 24 h of symptom onset and a follow-up was available at 90 days. Likewise, beta coefficients and odds ratios (ORs at 90 days) were calculated for different models: unadjusted (model 1), adjusted for age and sex (model 2), and adjusted for age, sex, (NIHSS at admission for outcome), LDL cholesterol, creatinine, prevalent arterial hypertension, prevalent diabetes, and prevalent hypercholesterolemia (model 3). Time-to-event analyses were not possible due to a fixed time-point for follow-up (90 days). All analyses for the validation cohort were performed in R, version 3.5.0.

      2.8 Data availability

      The data that support the findings of this study are available from the corresponding author upon reasonable request.

      3. Results

      3.1 SDMA, effective HDL cholesterol and cIMT

      Baseline characteristics of both cohorts including anthropometric measures and clinical presentation are given in Table 1. Biologically effective HDL cholesterol (HDL-C, calculated according to the previously proposed algorithm) median levels were 30.1 [21.2, 42.0] mg/dl and 23.1 [13.3, 34.6] mg/dl in MARK-STROKE and CIRCULAS, respectively (Table 1). HDL-C inversely correlated with age and creatinine in both studies (Supplementary Table 1). HDL-C was associated with cIMT in unadjusted and models adjusted for age, sex, and GFR in MARK-STROKE and CIRCULAS (Table 2). This association remained significant after additional adjustment for LDL cholesterol, prevalent arterial hypertension, diabetes and hypercholesterolemia only in MARK-STROKE and showed a trend in CIRCULAS (Table 2).
      Table 1Baseline characteristics.
      CharacteristicsMARK- STROKE (n = 299)CIRCULAS (n = 382)
      Demographic parameters
      Age, years70.1 ± 12.075.1 ± 11.2
      Male196 (66)207 (54)
      Smoking129 (43)122 (48)
      Hypertension226 (76)307 (82)
      Hyperlipidemia97 (32)134 (36)
      Diabetes51 (17)67 (18)
      Atrial fibrillation74 (25)103 (28)
      Prior myocardial infarct36 (12)38 (10)
      Prior stroke52 (17)88 (24)
      BMI, kg/m226.2 ± 4.326.3 ± 5.0
      Laboratory parameters
      Symptom to blood draw, h44.0 [24.5, 89.4]3.1 [1.4, 5.2]
      Cholesterol, mg/dL183 [152, 215]176 [146, 208]
      Triglycerides, mg/dl122 [90.5, 168]101 [77, 136]
      LDL cholesterol, mg/dL103 [75, 134]108 [ 83, 136]
      HDL cholesterol, mg/dL48.5 [39.0, 59.8]48 [40, 58]
      SDMA, μmol/L0.61 [0.55, 0.71]0.70 [0.59, 0.87]
      Effective HDL cholesterol, mg/dL30.1 [21.2, 42.0]23.1 [13.3, 34.6]
      CRP, mg/dL1.5 [0.9, 3.5]0.4 [0.2, 0.9]
      Creatinine, mg/dL0.96 [0.82, 1.20]1.00 [0.90, 1.20]
      Medication
      Blood-thinning256 (86)182 (49)
      Lipid-lowering214 (72)127 (35)
      Antihypertensive225 (75)254 (69)
      Neurological parameters
      TIA89 (30)0 (0)
      NIHSS, points1 [0, 4]5 [2, 12]
      mRS, stage1 [0, 2]3 [2, 4]
      Intima-media-thickness (mm)1.3 [1.1, 1.6]0.8 [0.7, 0.9]
      Symptomatic ICA stenosis46 (15)34 (9)
      Data are mean ± SD or median [IQR], as appropriate. Categorical variables are given as numbers (percentages) of participants. LDL, low-density lipoprotein; HDL, high-density lipoprotein; CK, creatine kinase; SDMA, symmetric dimethylarginine; CRP, C-reactive protein; TIA, transient ischemic attack; NIHSS, National Institute of Health Stroke Scale; mRS, modified Rankin Scale; ICA, internal carotid artery.
      Table 2Regression analysis of HDL-C levels with carotid intima-media thickness.
      Modelβ coefficient (95% CI)p value
      MARK-STROKE1−0.007 (−0.010, −0.003)0.001**
      2−0.006 (−0.010, −0.001)0.010*
      3−0.006 (−0.011, −0.001)0.010*
      CIRCULAS1−0.002 (−0.004, −0.001)0.003**
      2−0.002 (−0.003, −0.000)0.043*
      3−0.002 (−0.003, −0.000)0.079
      Linear regression analysis with beta coefficients (95% confidence interval) (model 1: unadjusted; model 2: adjusted for age, sex and GFR; model 3: adjusted for age, sex, GFR, prevalent arterial hypertension, prevalent diabetes and hypercholesterolemia) (MARK-STROKE: n = 299, CIRCULAS: n = 382). Models were calculated for one unit increase in effective high-density lipoprotein cholesterol (HDL-C′ in mg/dL) and one unit increase in carotid intima-media thickness (mm). *p < 0.05, **p < 0.01.

      3.2 SDMA, effective HDL cholesterol and incident MACE

      During follow-up (median 294 [IQR: 204, 439] days), we registered 24 incident MACE in 219 MARK-STROKE patients. Patients with HDL-C levels above the median had a longer disease-free survival and lower risk of incident MACE (Fig. 1A and Table 3, HR 0.15 [95% CI: 0.05, 0.47], model 3). In continuous Cox regression analysis, increasing HDL-C concentrations were incrementally associated with lower MACE incidence (HR 0.95 [95% CI: 0.92, 0.99] for one unit increase in mg/dL, model 3). Neither HDL cholesterol nor SDMA at baseline was associated with MACE in this cohort (Fig. 1B and C and Table 3). We validated these findings in the CIRCULAS cohort. We recorded 53 incident MACE in 213 stroke patients. During a follow-up of 90 days, HDL-C levels above the median were associated with fewer incident MACE, whereas HDL cholesterol and SDMA alone did not (Table 4, model 3). In addition, increasing HDL-C concentrations were incrementally associated with lower MACE incidence in Cox regression analysis in the CIRCULAS cohort (OR: 0.97 [95% CI: 0.94, 0.99] for one unit increase in mg/dL, model 3).
      Fig. 1
      Fig. 1Incident MACE after acute ischemic stroke or TIA.
      Kaplan-Meier curves for HDL-C (A), SDMA (B) and HDL cholesterol (C) with MACE (death, myocardial infarction, stroke) during follow-up after stroke or TIA in MARK-STROKE (n = 219). HDL, high-density lipoprotein; HDL-C, effective high-density lipoprotein cholesterol; MACE, major adverse cardiovascular events; SDMA, symmetric dimethylarginine.
      Table 3Cox regression analyses of HDL-C, SDMA and HDL cholesterol with incident MACE in MARK-STROKE.
      ModelHazard Ratio [95% CI]p value
      HDL-C10.18 [0.06, 0.54]0.002**
      20.17 [0.05, 0.51]0.002**
      30.15 [0.05, 0.47]0.001**
      SDMA12.00 [0.86, 4.68]0.109
      22.09 (0.78, 5.57]0.142
      32.26 [0.84, 6.07]0.107
      HDL cholesterol10.67 [0.30, 1.51]0.331
      20.71 [0.30, 1.69]0.441
      30.71 [0.30, 1.71]0.446
      Cox regression analysis of biomarker levels above the median with hazard ratios (95% confidence interval, CI) during median follow-up of 294 days. Model 1: unadjusted, model 2: adjusted for age, sex and GFR, model 3: adjusted for age, sex, GFR, LDL cholesterol, smoking, prevalent arterial hypertension, prevalent diabetes and hypercholesterolemia; n = 219. *p < 0.05, **p < 0.01. HDL, high-density lipoprotein; HDL-C′, effective high-density lipoprotein cholesterol; LDL, low-density lipoprotein; MACE, major adverse cardiovascular events; SDMA, symmetric dimethylarginine.
      Table 4Logistic regression analysis of effective HDL-C, SDMA and HDL cholesterol with incident MACE in CIRCULAS.
      ModelOdds Ratio [95% CI]p value
      HDL-C’10.50 [0.35, 0.72]<0.001***
      20.57 [0.38, 0.86]0.008**
      30.60 [0.38, 0.94]0.025*
      SDMA11.22 [0.90, 1.64]0.195
      21.05 [0.78, 1.42]0.754
      30.82 [0.36, 1.85]0.630
      HDL cholesterol10.68 [0.48, 0.96]0.030*
      20.67 [0.46, 0.99]0.044*
      30.48 [0.23, 1.01]0.054
      Logistic regression analysis of biomarker levels above the median with odds ratios (95% confidence interval, CI). Model 1: unadjusted; model 2: adjusted for age, sex, and GFR; model 3: adjusted for age, sex, GFR, LDL cholesterol, smoking, prevalent arterial hypertension, prevalent diabetes and hypercholesterolemia; n = 213. *p < 0.05, **p < 0.01, ***p < 0.001. HDL, high-density lipoprotein; HDL-C′, effective high-density lipoprotein cholesterol; LDL, low-density lipoprotein; MACE, major adverse cardiovascular events; SDMA, symmetric dimethylarginine.

      4. Discussion

      Here, we show that low HDL-C is associated with increased cIMT and incident MACE after stroke. Previous studies have shown opposite associations of HDL cholesterol and SDMA with carotid arteriopathy. A meta-analysis showed a robust inverse correlation of total HDL cholesterol with carotid IMT [
      • Touboul P.J.
      • Labreuche J.
      • Bruckert E.
      • et al.
      HDL-C, triglycerides and carotid IMT: a meta-analysis of 21,000 patients with automated edge detection IMT measurement.
      ], whereas carotid IMT was positively associated with SDMA concentrations. [
      • Mels C.M.C.
      • Schutte A.E.
      • Huisman H.W.
      • et al.
      Asymmetric dimethylarginine and symmetric dimethylarginine prospectively relates to carotid wall thickening in black men: the SABPA study.
      ] In this study, HDL-C was independently associated with cIMT after adjustment. The anti-arteriosclerotic effects of HDL have been attributed to reverse cholesterol transport. In line with this mechanism, higher cholesterol efflux capacity was associated with cIMT, progression of carotid plaques, incident cardiovascular events and coronary disease status. [
      • Khera A.V.
      • Demler O.V.
      • Adelman S.J.
      • et al.
      Cholesterol efflux capacity, high-density lipoprotein particle number, and incident cardiovascular events: an analysis from the JUPITER trial (Justification for the use of statins in prevention: an intervention trial evaluating rosuvastatin).
      ,
      • Rohatgi A.
      • Khera A.
      • Berry J.D.
      • et al.
      HDL cholesterol efflux capacity and incident cardiovascular events.
      ,
      • Shea S.
      • Stein J.H.
      • Jorgensen N.W.
      • et al.
      Cholesterol mass efflux capacity, incident cardiovascular disease, and progression of carotid plaque.
      ] In these studies, cholesterol efflux capacity was minimally influenced by traditional risk factors and HDL cholesterol itself. [
      • Khera A.V.
      • Demler O.V.
      • Adelman S.J.
      • et al.
      Cholesterol efflux capacity, high-density lipoprotein particle number, and incident cardiovascular events: an analysis from the JUPITER trial (Justification for the use of statins in prevention: an intervention trial evaluating rosuvastatin).
      ,
      • Rohatgi A.
      • Khera A.
      • Berry J.D.
      • et al.
      HDL cholesterol efflux capacity and incident cardiovascular events.
      ] In contrast, SDMA strongly and dose-dependently reduced cholesterol efflux capacity. [
      • Zewinger S.
      • Kleber M.E.
      • Rohrer L.
      • et al.
      Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease.
      ] SDMA is a predictor of all-cause mortality after ischemic stroke but the overall value of SDMA as a biomarker of cardiovascular disease is unclear. [
      • Schulze F.
      • Carter A.M.
      • Schwedhelm E.
      • et al.
      Symmetric dimethylarginine predicts all-cause mortality following ischemic stroke.
      ,
      • Grosse G.M.
      • Schwedhelm E.
      • Worthmann H.
      • Choe C.U.
      Arginine derivatives in cerebrovascular diseases: mechanisms and clinical implications.
      ] In two cardiovascular cohorts, higher HDL cholesterol levels were associated with lower mortality only in patients with low SDMA levels, whereas this association was completely lost if SDMA was high. [
      • Zewinger S.
      • Kleber M.E.
      • Rohrer L.
      • et al.
      Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease.
      ] Moreover, high SDMA can transform HDL not only into a dysfunctional, but “toxic” lipoprotein, which impairs endothelial repair and triggers pro-inflammatory cascades. [
      • Speer T.
      • Rohrer L.
      • Blyszczuk P.
      • et al.
      Abnormal high-density lipoprotein induces endothelial dysfunction via activation of Toll-like receptor-2.
      ] Mechanistically, SDMA can trigger micro- and macrovascular inflammation and can activate store-operated Ca2+-channels increasing intracellular Ca2+ in monocytes. [
      • Grosse G.M.
      • Schwedhelm E.
      • Worthmann H.
      • Choe C.U.
      Arginine derivatives in cerebrovascular diseases: mechanisms and clinical implications.
      ,
      • Schepers E.
      • Glorieux G.
      • Dhondt A.
      • Leybaert L.
      • Vanholder R.
      Role of symmetric dimethylarginine in vascular damage by increasing ROS via store-operated calcium influx in monocytes.
      ] In line with these findings, HDL-C predicted incident MACE after stroke in two independent stroke cohorts, whereas absolute HDL cholesterol and SDMA did not. The association of HDL-C with outcome was independent of traditional risk factors. Similar to HDL-C, cholesterol efflux capacity is minimally affected by these factors, whereas HDL cholesterol concentrations are strongly associated with multiple metabolic variables and cardiovascular risk factors. [
      • Rohatgi A.
      • Khera A.
      • Berry J.D.
      • et al.
      HDL cholesterol efflux capacity and incident cardiovascular events.
      ] Our data suggest that HDL-C has the discriminatory potential to improve individual risk stratification and to facilitate a more personalized treatment of stroke patients. Our findings sketch potential treatment regimes, which are not based on absolute lipid concentrations, but functionality. In this case, patients with cerebrovascular disease and normal absolute lipid levels might benefit from statin therapy if biologically effective HDL levels are low.
      Limitations of our study are the small sample sizes in both cohorts and the restriction of analyses to SDMA ≥0.48 μmol/L. Furthermore, the observational design of our study does not allow causal relationships.
      In conclusion, our findings imply a detrimental role of low HDL-C concentrations in acute stroke independent of traditional risk factors and underline the importance of lipoprotein functionality.

      Financial support

      Dr. Choe and Dr. Schulz were supported by an Else Kröner Exzellenzstipendium from the Else Kröner-Fresenius Stiftung (grant numbes: 2018_EKES.04 to Dr. Choe, 2020_EKES.16 to Dr. Schulz). Dr. Tiedt received funding from the Corona foundation , outside the submitted work. ST received funding from the Corona foundation ( S199/10081/2020 ) and the Leducq foundation ( 21CVD04 ).

      CRediT authorship contribution statement

      Edzard Schwedhelm: Conceptualization, Methodology, Investigation, Data curation, Writing – review & editing. Steffen Tiedt: Conceptualization, Methodology, Formal analysis, Investigation, Data curation, Writing – review & editing. Susanne Lezius: Methodology, Formal analysis, Writing – review & editing. Teresa Allegra Wölfer: Investigation, Data curation, Writing – review & editing. Märit Jensen: Investigation, Data curation, Writing – review & editing. Robert Schulz: Investigation, Data curation, Writing – review & editing. Rainer Böger: Investigation, Data curation, Writing – review & editing. Christian Gerloff: Investigation, Data curation, Writing – review & editing. Götz Thomalla: Investigation, Data curation, Writing – review & editing. Chi-un Choe: Conceptualization, Methodology, Formal analysis, Data curation, Writing – original draft.

      Declaration of interests

      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

      Appendix A. Supplementary data

      The following is the Supplementary data to this article:

      References

        • Rohatgi A.
        • Westerterp M.
        • von Eckardstein A.
        • Remaley A.
        • Rye K.A.
        HDL in the 21st century: a multifunctional roadmap for future HDL research.
        Circulation. 2021 Jun 8; 143: 2293-2309
        • Sorrentino S.A.
        • Besler C.
        • Rohrer L.
        • et al.
        Endothelial-vasoprotective effects of high-density lipoprotein are impaired in patients with type 2 diabetes mellitus but are improved after extended-release niacin therapy.
        Circulation. 2010 Jan 5; 121: 110-122
        • Speer T.
        • Rohrer L.
        • Blyszczuk P.
        • et al.
        Abnormal high-density lipoprotein induces endothelial dysfunction via activation of Toll-like receptor-2.
        Immunity. 2013 Apr 18; 38: 754-768
        • Schwedhelm E.
        • Boger R.H.
        The role of asymmetric and symmetric dimethylarginines in renal disease.
        Nat. Rev. Nephrol. 2011 May; 7: 275-285
        • Zewinger S.
        • Kleber M.E.
        • Rohrer L.
        • et al.
        Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease.
        Eur. Heart J. 2017 May 21; 38: 1597-1607
        • Zhang F.
        • Liu L.
        • Zhang C.
        • Ji S.
        • Mei Z.
        • Li T.
        Association of metabolic syndrome and its components with risk of stroke recurrence and mortality: a meta-analysis.
        Neurology. 2021 Aug 17; 97: e695-e705
        • Schwedhelm E.
        • von Lucadou M.
        • Peine S.
        • et al.
        Trimethyllysine, vascular risk factors and outcome in acute ischemic stroke (MARK-STROKE).
        Amino Acids. 2021 Apr; 53: 555-561
        • Rosenkranz M.
        • Russjan A.
        • Goebell E.
        • et al.
        Carotid plaque surface irregularity predicts cerebral embolism during carotid artery stenting.
        Cerebrovasc. Dis. 2011; 32: 163-169
        • Touboul P.J.
        • Hennerici M.G.
        • Meairs S.
        • et al.
        Mannheim carotid intima-media thickness and plaque consensus (2004-2006-2011). An update on behalf of the advisory board of the 3rd, 4th and 5th watching the risk symposia, at the 13th, 15th and 20th European Stroke Conferences, Mannheim, Germany, 2004, Brussels, Belgium, 2006, and Hamburg, Germany, 2011.
        Cerebrovasc. Dis. 2012; 34: 290-296
        • Sharma K.
        • Blaha M.J.
        • Blumenthal R.S.
        • Musunuru K.
        Clinical and research applications of carotid intima-media thickness.
        Am. J. Cardiol. 2009 May 1; 103: 1316-1320
        • Choe C.U.
        • Atzler D.
        • Wild P.S.
        • et al.
        Homoarginine levels are regulated by L-arginine:glycine amidinotransferase and affect stroke outcome: results from human and murine studies.
        Circulation. 2013 Sep 24; 128: 1451-1461
        • Tiedt S.
        • Brandmaier S.
        • Kollmeier H.
        • et al.
        Circulating metabolites differentiate acute ischemic stroke from stroke mimics.
        Ann. Neurol. 2020 Oct; 88: 736-746
        • Schwedhelm E.
        Quantification of ADMA: analytical approaches.
        Vasc. Med. 2005 Jul; 10: S89-S95
        • Touboul P.J.
        • Labreuche J.
        • Bruckert E.
        • et al.
        HDL-C, triglycerides and carotid IMT: a meta-analysis of 21,000 patients with automated edge detection IMT measurement.
        Atherosclerosis. 2014 Jan; 232: 65-71
        • Mels C.M.C.
        • Schutte A.E.
        • Huisman H.W.
        • et al.
        Asymmetric dimethylarginine and symmetric dimethylarginine prospectively relates to carotid wall thickening in black men: the SABPA study.
        Amino Acids. 2017 Nov; 49: 1843-1853
        • Khera A.V.
        • Demler O.V.
        • Adelman S.J.
        • et al.
        Cholesterol efflux capacity, high-density lipoprotein particle number, and incident cardiovascular events: an analysis from the JUPITER trial (Justification for the use of statins in prevention: an intervention trial evaluating rosuvastatin).
        Circulation. 2017 Jun 20; 135: 2494-2504
        • Rohatgi A.
        • Khera A.
        • Berry J.D.
        • et al.
        HDL cholesterol efflux capacity and incident cardiovascular events.
        N. Engl. J. Med. 2014 Dec 18; 371: 2383-2393
        • Shea S.
        • Stein J.H.
        • Jorgensen N.W.
        • et al.
        Cholesterol mass efflux capacity, incident cardiovascular disease, and progression of carotid plaque.
        Arterioscler. Thromb. Vasc. Biol. 2019 Jan; 39: 89-96
        • Schulze F.
        • Carter A.M.
        • Schwedhelm E.
        • et al.
        Symmetric dimethylarginine predicts all-cause mortality following ischemic stroke.
        Atherosclerosis. 2010 Feb; 208: 518-523
        • Grosse G.M.
        • Schwedhelm E.
        • Worthmann H.
        • Choe C.U.
        Arginine derivatives in cerebrovascular diseases: mechanisms and clinical implications.
        Int. J. Mol. Sci. 2020 Mar 5; : 21
        • Schepers E.
        • Glorieux G.
        • Dhondt A.
        • Leybaert L.
        • Vanholder R.
        Role of symmetric dimethylarginine in vascular damage by increasing ROS via store-operated calcium influx in monocytes.
        Nephrol. Dial. Transplant. 2009 May; 24: 1429-1435