Hyperlipidemias: Rodríguez C

Rodríguez C, Slevin M, Rodríguez-Calvo R, Kumar S, Krupinski J, Tejerina T, Martínez-González J. · Centro de Investigación Cardiovascular (CSIC-ICCC), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. · Pathobiology. · Pubmed #19188746 No free full text.

Abstract: The endothelium regulates vascular homeostasis and is responsible for angiogenesis, a process mediated by the sprouting of endothelial cells from pre-existing vessels. Several lines of evidence indicate that endothelial progenitor cells (EPCs) also play a role in adult neovascularization as well as in the maintenance of endothelial integrity and function. Hypercholesterolemia is associated with increased cardiovascular risk by inducing a cascade of events leading to endothelial dysfunction and injury. Growing evidence indicates that low-density lipoproteins (LDLs) impair endothelial reparative processes by inducing endothelial cell apoptosis but also by reducing the number and function of EPCs. The involvement of LDLs in mechanisms associated with vascular repair and neovascularization is also suggested by data from studies using lipid-lowering drugs (statins). This review is focused on the central role of the cholesterol pathway in the biology of the endothelium and EPCs.

Muñoz S, Merlos M, Zambón D, Rodríguez C, Sabaté J, Ros E, Laguna JC. · Pharmacology Unit, School of Pharmacy, University of Barcelona, Barcelona, Spain. · J Lipid Res. · Pubmed #11734580 links to  free full text

Abstract: In a randomized, cross-over feeding trial involving 10 men with polygenic hypercholesterolemia, a control, Mediterranean-type cholesterol-lowering diet, and a diet of similar composition in which walnuts replaced approximately 35% of energy from unsaturated fat, were given for 6 weeks each. Compared with the control diet, the walnut diet reduced serum total and LDL cholesterol by 4.2% (P = 0.176), and 6.0% (P = 0.087), respectively. No changes were observed in HDL cholesterol, triglycerides, and apolipoprotein A-I levels or in the relative proportion of protein, triglycerides, phospholipids, and cholesteryl esters in LDL particles. The apolipoprotein B level declined in parallel with LDL cholesterol (6.0% reduction). Whole LDL, particularly the triglyceride fraction, was enriched in polyunsaturated fatty acids from walnuts (linoleic and alpha-linolenic acids). In comparison with LDL obtained during the control diet, LDL obtained during the walnut diet showed a 50% increase in association rates to the LDL receptor in human hepatoma HepG2 cells. LDL uptake by HepG2 cells was correlated with alpha-linolenic acid content of the triglyceride plus cholesteryl ester fractions of LDL particles (r(2) = 0.42, P < 0.05). Changes in the quantity and quality of LDL lipid fatty acids after a walnut-enriched diet facilitate receptor-mediated LDL clearance and may contribute to the cholesterol-lowering effect of walnut consumption.

González-Posada JM, Pérez Tamajón L, Caballero A, Laynez I, Marrero D, Rodríguez C, Bravo A, Meneses M, Alarco A, Morcillo L, Hernández D. · Servicio de Nefrología, Hospital Universitario de Canarias, Ofra, s/n,38230 Sta. Cruz de Tenerife, La Laguna. · Nefrologia. · Pubmed #16053013 No free full text.

Abstract: The prognosis of type 1 diabetes mellitus (T1DM) patients with chronic renal failure (CRF) improves after simultaneous pancreas-kidney (SPK) transplantation. In order to evaluate the changes in cardio-vascular risk (CVR) factors after SKP, we studied nine recipients before and 6 months after SPK. There were five females and four males, with a mean age of 37 +/- 8 years, duration of diabetes of 24 +/- 5 years, three of them before starting dialysis, and six on dialysis (hemodialysis = 5; peritoneal dialysis = 1). Before SPK, all patients received anti-hypertensive therapy (1-4 drugs; mean 2.2 +/- 0.9) and eight received statins. At 6 months after SPK, all patients were under triple immunosuppressive therapy (steroids + tacrolimus + MMF) without statins. They had normal renal function (Plasma Creatinine = 1.2 +/- 0.3 mg/dl) and pancreatic endocrine function (glycemia = 80 +/- 8 mg/dl). HbA1c decreased significantly (8.4 +/- 1.2 vs 4.7 +/- 0.6%; p < 0.007) with a value > 7% in seven patients before SPK and in none 6 months after SKP transplantation (p < 0.001). Although Body Mass Index increased (23 +/- 2 vs 25 +/- 3 kg/m2; p < 0.05), plasma triglycerides decreased (130 +/- 51 vs 88 +/- 33 mg/dl; p < 0.05), and total cholesterol, LDL-cholesterol and HDL-cholesterol were similar. Systolic and diastolic blood pressure (BP) decreased (156 +/- 7 vs 133 +/- 15; p < 0.01 and 96 +/- 7 vs 79 +/- 9; p < 0.007) with only two patients on anti-hypertensive therapy (1 drug). Likewise, before transplantation all patients were hypertensive (six grade 1 and three grade 2) while this was observed in only two at the end of follow-up (both grade 1) (p < 0.001). In conclusion, SPK transplantation with good renal and pancreatic function is associated with a short-term improvement in CVR profile.

Llorente-Cortés V, Otero-Viñas M, Sánchez S, Rodríguez C, Badimon L. · Cardiovascular Research Center, IICB (CSIC)-ICCC, Barcelona. Spain. · Circulation. · Pubmed #12473559 links to  free full text

Abstract: BACKGROUND: Low-density lipoprotein (LDL) receptor-related protein (LRP) is highly expressed in vascular smooth muscle cells (VSMCs) of both normal and atherosclerotic lesions. However, little is known about LRP regulation in the vascular wall. METHODS AND RESULTS: We analyzed the regulation of LRP expression in vitro in human VSMCs cultured with native LDL (nLDL) or aggregated LDL (agLDL) by semiquantitative reverse transcriptase-polymerase chain reaction, real-time polymerase chain reaction, and Western blot and in vivo during diet-induced hypercholesterolemia by in situ hybridization. LRP expression in human VSMCs is increased by nLDL and agLDL in a time- and dose-dependent manner. Maximal induction of LRP mRNA expression was observed after 24 hours of exposure to LDL. However, agLDL induced higher LRP mRNA expression (3.0-fold) than nLDL (1.76-fold). LRP mRNA upregulation was associated with an increase on LRP protein expression with the greatest induction by agLDL. VSMC-LRP upregulation induced by nLDL or agLDL was reduced by an inhibitor of sterol regulatory element binding protein (SREBP) catabolism (N-acetyl-leucyl-leucyl-norleucinal). In situ hybridization analysis indicates that there is a higher VSMC-LRP expression in hypercholesterolemic than in normocholesterolemic pig aortas. CONCLUSIONS: These results indicate that LRP expression in VSMCs is upregulated by intravascular and systemic LDL.

Rodríguez C, Raposo B, Martínez-González J, Casaní L, Badimon L. · Instituto de Investigación Cardiovascular de Barcelona, CSIC-ICCC-Hospital de Sant Pau, Barcelona, Spain. · Arterioscler Thromb Vasc Biol. · Pubmed #12231558 links to  free full text

Abstract: OBJECTIVE: Hypercholesterolemia induces endothelial dysfunction, a hallmark of the atherosclerotic process, modulating the expression of key genes in vascular endothelial cells. METHODS AND RESULTS: By differential display analysis, we have studied the effect of high concentrations of native low density lipoprotein (LDL) on endothelial gene expression. mRNA levels of lysyl oxidase (LOX), an enzyme involved in collagen and elastin cross-linking, were downregulated by LDL treatment in endothelial cells in a dose- and time-dependent manner (80% of inhibition by 180 mg/dL LDL for 24 hours). This reduction of LOX expression was associated with a decrease in LOX activity (40% and 54% of inhibition after 24 and 48 hours of LDL treatment, respectively). LOX mRNA half-life was not modified by LDL, but transcriptional inhibition blocked the effect of LDL. Inhibition of LOX activity by either LDL or beta-aminopropionitrile, an inhibitor of LOX, increased endothelial permeability (192+/-0.19- and 3.37+/-0.74-fold, respectively). Interestingly, a reduction in LOX expression (3.5-fold) was observed in vivo in the vascular wall of hypercholesterolemic pigs. CONCLUSIONS: These findings suggest that LDL downregulation of LOX could contribute to the endothelial dysfunction caused by hypercholesterolemia, thus contributing to atherosclerotic plaque formation.

Rodríguez C, Martínez-González J, Sánchez-Gómez S, Badimon L. · Cardiovascular Research Center, Instituto de Investigaciones Biomédicas de Barcelona/Consejo Superior de Investigaciones Cientificas-Institut de Recerca Hospital de la Santa Creu i Sant Pau-UAB, Barcelona, Spain. · Circ Res. · Pubmed #11179193 links to  free full text

Abstract: Hypercholesterolemia is associated with endothelial dysfunction and atherosclerotic lesion formation. By mRNA-differential display analysis, we have identified lanosterol 14alpha-demethylase (CYP51) as a gene highly regulated by native LDLs (nLDLs) in endothelial cells. CYP51 is a cytochrome P-450 enzyme involved in the postsqualene phases of cholesterol biosynthesis. CYP51 mRNA levels decrease in nLDL-treated cells in a dose- and time-dependent manner (9-fold after 24 hours with 180 mg of LDL cholesterol per deciliter), an effect that is blocked by cycloheximide. In parallel, sterol regulatory element (SRE) binding protein-2 (SREBP-2) expression falls (10-fold), without alteration in SREBP-1 level. N:-Acetyl-leucyl-leucyl-norleucinal, which inhibits catabolism of the active form of SREBPs, abolished the effect of high concentrations of nLDL on CYP51 expression. Gel-shift assays performed with the SRE of the cyp51 gene (cyp51-SRE) revealed a diminished SREBP-SRE interaction in LDL-treated cells. Moreover, nLDLs downregulate CYP51 promoter activity in transfection assays. Thus, atherogenic levels of nLDL downregulate endothelial CYP51 mRNA levels through a reduction in SRE-SREBP-2 interaction. Additionally, SREBP-2 and CYP51 mRNA levels are decreased in the arterial wall of hypercholesterolemic pigs. In summary, we have described for the first time, both in in vivo and in vitro systems, that CYP51 is expressed in the vascular wall and that it is downregulated together with SREBP-2 by high levels of nLDL. Because this transcription factor controls multiple cell lipid metabolism pathways, its regulation by nLDL could play a key role in lipid-mediated endothelial dysfunction.