Advertisement

Inhibition of oxidized LDL aggregation with the calcium channel blocker amlodipine: role of electrostatic interactions

      Abstract

      Atherogenic low-density lipoproteins (LDL) are characterized by elevations in cholesterol content and increased electronegativity, factors that contribute to aggregation and foam cell formation. This study was designed to test the effect of the positively charged calcium channel blocker (CCB) amlodipine on the aggregation properties of oxidized LDL lipids. Large unilamellar vesicles (LUVs) (100 nm diameter) labeled with a non-exchangeable marker [3H]cholesteryl hexadecyl ether were prepared with lipids extracted from human LDL following oxidation. The LUVs were shown to bind, in a reversible fashion, to charged diethylaminoethyl Sephadex columns. The addition of amlodipine inhibited binding of the oxidized LDL lipids in a dose-dependent fashion with an IC50 in the nanomolar range as a result of its high lipophilicity and positively charged amino group (pKa of 9.02). The activity of amlodipine was reproduced in model membranes that contained fixed amounts of charged phospholipid (glycerophospholipid) in a concentration-dependent manner. By contrast, drugs lacking a formal positive charge, including CCBs (felodipine, nifedipine, diltiazem, verapamil) and an angiotensin-converting enzyme-inhibitor (ramiprilate) had no effect on the column binding of the modified, electronegative lipids. These effects of amlodipine on LDL lipid aggregation and electrostatic properties may represent a novel antiatherosclerotic mechanism of action.

      Keywords

      Abbreviations:

      LDL, low-density lipoproteins (), CCBs, calcium channel blockers (), ACE, angiotensin-converting enzyme (), POPG, 1-palmitoyl-2-oleoyl-phosphatidylglycerol (), POPC, 1-palmitoyl-2-oleoyl-phosphatidylcholine (), CHE, cholesteryl hexadecyl ether (), DEAE, diethylaminoethyl (), HPLC, high-performance liquid chromatography (), LUV, large unilamellar vesicle ()
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Atherosclerosis
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Quinn M.T.
        • Parthasarathy S.
        • Fong L.G.
        • Steinberg D.
        Oxidatively modified low density lipoproteins: a potential role in recruitment and retention of monocyte/macrophages during atherogenesis.
        Proc. Natl. Acad. Sci. USA. 1987; 84: 2995-2998
        • Suits A.G.
        • Chait A.
        • Aviram M.
        • Heinecke J.W.
        Phagocytosis of aggregated lipoprotein by macrophages: low density lipoprotein receptor-dependent foam-cell formation.
        Proc. Natl. Acad. Sci. USA. 1989; 86: 2713-2717
        • Zhang W.Y.
        • Gaynor P.M.
        • Kruth H.S.
        Aggregated low density lipoprotein induces and enters surface-connected compartments of human monocyte–macrophages.
        J. Biol. Chem. 1997; 272: 31700-31706
        • Frostegard J.
        • Haegerstrand A.
        • Gidlund M.
        • Nilsson J.
        Biologically modified LDL increases the adhesive properties of endothelial cells.
        Atherosclerosis. 1991; 90: 119-126
        • Schwartz C.J.
        • Valente A.J.
        • Sprague E.A.
        • Kelley J.L.
        • Nerem R.M.
        The pathogenesis of atherosclerosis: an overview.
        Clin. Cardiol. 1991; 14: I1-I16
        • Cathcart M.K.
        • Morel D.W.
        • Chisolm III, G.M.
        Monocytes and neutrophils oxidize low density lipoprotein making it cytotoxic.
        J. Leukoc. Biol. 1985; 38: 341-350
        • Carew T.E.
        • Schwenke D.C.
        • Steinberg D.
        Antiatherogenic effect of probucol unrelated to its hypocholesterolemic effect: evidence that antioxidants in vivo can selectively inhibit low density lipoprotein degradation in macrophage-rich fatty streaks and slow the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit.
        Proc. Natl. Acad. Sci. USA. 1987; 84: 7725-7729
        • Sasahara M.
        • Raines E.W.
        • Chait A.
        • et al.
        Inhibition of hypercholesterolemia-induced atherosclerosis in the nonhuman primate by probucol. I. Is the extent of atherosclerosis related to resistance of LDL to oxidation.
        J. Clin. Invest. 1994; 94: 155-164
        • Belcher J.D.
        • Balla J.
        • Balla G.
        • et al.
        Vitamin E, LDL, and endothelium. Brief oral vitamin supplementation prevents oxidized LDL-mediated vascular injury in vitro.
        Arterioscler. Thromb. 1993; 13: 1779-1789
        • Cote G.
        • Tardif J.-C.
        • Lesperance J.
        • et al.
        Effects of probucol on vascular remodeling after coronary angioplasty.
        Circulation. 1999; 99: 30-35
        • Mason R.P.
        • Moisey D.M.
        • Shajenko L.
        Cholesterol alters the binding of Ca2+ channel blockers to the membrane lipid bilayer.
        Mol. Pharmacol. 1992; 41: 315-321
        • Mason R.P.
        • Campbell S.F.
        • Wang S.D.
        • Herbette L.G.
        Comparison of location and binding for the positively charged 1,4-dihydropyridine calcium channel antagonist amlodipine with uncharged drugs of this class in cardiac membranes.
        Mol. Pharmacol. 1989; 36: 634-640
        • Bauerle H.D.
        • Seelig J.
        Interaction of charged and uncharged calcium channel antagonists with phospholipid membranes. Binding equilibrium, binding enthalpy, and membrane location.
        Biochemistry. 1991; 30: 7203-7211
        • Mason R.P.
        • Walter M.F.
        • Trumbore M.W.
        • Olmstead Jr., E.G.
        • Mason P.E.
        Membrane antioxidant effects of the charged dihydropyridine calcium antagonist amlodipine.
        J. Mol. Cell Cardiol. 1999; 31: 275-281
        • Tulenko T.N.
        • Laury-Kleintop L.
        • Walter M.F.
        • Mason R.P.
        Cholesterol, calcium and atherosclerosis: Is there a role for calcium channel blockers in atheroprotection?.
        Int. J. Cardiol. 1997; 62: 55S-66S
        • Byingyton R.
        • Riley W.
        • Booth D.
        • et al.
        Effect of amlodipine on progression of carotid atherosclerosis in patients with documented heart disease.
        Am. J. Hypertens. 1999; 12: 42A-43A
        • Pitt B.
        • Byingyton R.P.
        • Furberg C.D.
        • et al.
        Effect of amlodipine on the progression of atherosclerosis and the occurrence of clinical events.
        Circulation. 2000; 102: 1503-1510
        • Tulenko T.N.
        • Chen M.
        • Mason P.E.
        • Mason R.P.
        Physical effects of cholesterol on arterial smooth muscle membranes: evidence of immiscible cholesterol domains and alterations in bilayer width during atherogenesis.
        J. Lipid Res. 1998; 39: 947-956
        • Kellner-Weibel G.
        • Yancey P.G.
        • Jerome W.G.
        • et al.
        Cystallization of free cholesterol in model macrophage foam cells.
        Arterioscler. Thromb. Vasc. Biol. 1999; 19: 1891-1898
        • Rodrigueza W.V.
        • Wheeler J.J.
        • Klimuk S.K.
        • Kitson C.N.
        • Hope M.J.
        Transbilayer movement and net flux of cholesterol and cholesterol sulfate between liposomal membranes.
        Biochemistry. 1995; 34: 6208-6217
        • Phillips J.E.
        • Rodrigueza W.V.
        • Johnson W.J.
        Basis for rapid efflux of biosynthetic desmosterol from cells.
        J. Lipid Res. 1998; 39: 2459-2470
        • Bangham A.D.
        • Standish M.M.
        • Watkins J.C.
        Diffusion of univalent ions across the lamellae of swollen phospholipids.
        J. Mol Biol. 1965; 13: 238-252
        • Steinberg D.
        • Parthasarathy S.
        • Carew T.E.
        • Khoo J.C.
        • Witztum J.L.
        Beyond cholesterol. Modifications of low-density lipoprotein that increase its atherogenicity.
        N. Engl. J. Med. 1989; 320: 915-924
        • Steinbrecher U.P.
        • Lougheed M.
        • Kwan W.C.
        • Dirks M.
        Recognition of oxidized low density lipoprotein by the scavenger receptor of macrophages results from derivatization of apolipoprotein B by products of fatty acid peroxidation.
        J. Biol. Chem. 1989; 264: 15216-15223
        • Frostegard J.
        • Nilsson J.
        • Haegerstrand A.
        • Hamsten A.
        • Wigzell H.
        • Gidlund M.
        Oxidized low density lipoprotein induces differentiation and adhesion of human monocytes and the monocytic cell line U937.
        Proc. Natl. Acad. Sci. USA. 1990; 87: 904-908
        • Kodama T.
        • Freeman M.
        • Rohrer L.
        • Zabrecky J.
        • Matsudaira P.
        • Krieger M.
        Type I macrophage scavenger receptor contains alpha-helical and collagen-like coiled coils.
        Nature. 1990; 343: 531-535
        • Rohrer L.
        • Freeman M.
        • Kodama T.
        • Penman M.
        • Krieger M.
        Coiled-coil fibrous domains mediate ligand binding by macrophage scavenger receptor type II.
        Nature. 1990; 343: 570-572
        • Waters D.
        • Lesperance J.
        • Francetich M.
        • et al.
        A controlled clinical trial to assess the effect of a calcium channel blocker on the progression of coronary atherosclerosis.
        Circulation. 1990; 82: 1940-1953
        • Lichtlen P.R.
        • Hugenholtz P.G.
        • Rafflenbeul W.
        • Hecker H.
        • Jost S.
        • Deckers J.W.
        Retardation of angiographic progression of coronary artery disease by nifedipine. Results of the International Nifedipine trial on Antiatherosclerotic Therapy (INTACT).
        Lancet. 1990; 335: 1109-1113
        • Borhani N.O.
        • Mercuri M.
        • Borhani P.A.
        • et al.
        Final outcome results of the Multicenter Isradipine Diuretic Atherosclerosis Study (MIDAS). A randomized controlled trial.
        JAMA. 1996; 276: 785-791