Molecular basis for the effect of lipid lowering drugs on growth factors after de-endothelialization.

She M.

Department of Pathology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100005, China.

OBJECTIVE: To study the mechanism and effect of lipid lowering drugs in arresting the development of arterial restenosis after angioplasty. METHODS: De-endothelialization injury of rabbit aortae, common iliac and femoral arteries using balloon angioplasty and the expression of growth factors such as platelet derived growth factor-B (PDGF-B), transforming growth factor beta-1 (TGF beta-1), and fibroblast growth factors (bFGF) were investigated. Total serum cholesterol (TC) and triglycerides (TG) were analyzed during and after the treatment using either simvastatin combined with gemfibrozil or simvastatin alone for 6 weeks. RESULTS: Serum total cholesterol and triglycerides were only slightly to moderately increased after high cholesterol ration intake lasting for 6 weeks in rabbits of two therapeutic groups (simvastatin plus gemfibrozil or only simvastatin). A positive correlation was found between TC and intimal/medial ratio (r = 0.5873, P < 0.05). PDGF-B detected by immuno-histochemistry and RT-PCR analysis showed that the release of PDGF-B was inhibited by simvastatin and gemfibrozil after de-endothelialization. RT-PCR analysis showed that TGF beta-1 was increased in the neointima in two treatment groups but no definite change was seen in the mRNA of bFGF in the smooth muscle cell (SMC) of the balloon-injured arteries even under lipid lowering drug treatment. CONCLUSION: In addition to the lipid lowering effect, both simvastatin and gemfibrozil also influence the release of PDGF-Band TGF-1 in the neointima after de-endothelialization.

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Efficacy and safety of simvastatin in Asian and non-Asian coronary heart disease patients: a comparison of the GOALLS and STATT studies.

Bilheimer D.

Manila Doctor's Hospital, Manila, Philippines. ddmclinic edsamail.com.ph

BACKGROUND: Asians are thought to be more responsive to the lipid-lowering effects of statins than non-Asians although there are no head-to-head trials that examine this perception. OBJECTIVE: To compare the results of the GOALLS and STATT studies that used similar titrate-to-goal protocols with 20 mg up to 80 mg simvastatin in Asian and non-Asian coronary heart disease (CHD) patients. METHODS: GOALLS (N = 198; included non-Asians and Asians) and STATT (N = 133; included Asians only) were both multi-center, open-label 14-week studies in CHD patients with serum low density lipoprotein cholesterol (LDL-C) levels 115 mg/dL-180 mg/dL and triglycerides (TG) levels < or = 400 mg/dL. Simvastatin was titrated from 20 mg/day up to 80 mg/day in order to achieve the National Cholesterol Education Program (NCEP) LDL-C target < or = 100 mg/dL. The primary efficacy variable was the percentage of patients attaining the NCEP LDL-C target at Week 14. Secondary endpoints included proportion of patients achieving the European Society of Cardiology/European Atherosclerosis Society/European Society of Hypertension (European) LDL-C target < or = 115 mg/dL at Week 14 and percentage change in lipid parameters. Safety and tolerability were assessed by monitoring adverse experiences and safety laboratory tests. Fifteen Asian patients were part of the GOALLS cohort and their data were compared separately with results of non-Asians from GOALLS and Asians from the STATT study. RESULTS: After 14 weeks of simvastatin treatment, 87.1% of GOALLS non-Asians, 85.7% of GOALLS Asians, and 78.2% of STATT patients attained the NCEP LDL-C target. At Week 14, 94.4%, 92.9%, and 91.7% of the GOALLS non-Asians, GOALLS Asians, and STATT patients achieved the European LDL-C target, respectively. The average treatment doses to attain NCEP and European targets were comparable among groups. The percentage reductions in lipid parameters from baseline to week 14 were similar among groups except, changes in high density lipoprotein cholesterol and apolipoprotein A-I favored Asian subjects. There was also a greater reduction in TG in the STATT study, but this was not consistent with TG reductions experienced by Asians in the GOALLS study. In both studies, simvastatin was generally well tolerated by all patients across the dosage range of 20 mg-80 mg. No cases of rhabdomyolysis or myopathy were reported in either study. CONCLUSIONS: A great majority of CHD patients is able to achieve LDL-C treatment goals (up to 90%) on simvastatin regardless of racial background. Simvastatin treatment at doses of 20 mg-80 mg is well-tolerated in Asian and non-Asian CHD patients. This side-by-side comparison provides evidence that Asian and non-Asian CHD populations respond similarly to comparable doses of simvastatin.

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Combined endothelial nitric oxide synthase upregulation and caveolin-1 downregulation decrease leukocyte adhesion in pial venules of ovariectomized female rats.

Pelligrino DA.

Neuroanesthesia Research Laboratory, Department of Anesthesiology, University of Illinois at Chicago, 60607, USA. rasp uic.edu

BACKGROUND AND PURPOSE: We recently found that chronic estrogen depletion enhances leukocyte adhesion in pial venules in the female rat, while estrogen repletion decreases it. Estrogen-associated repression of inflammation may be due to upregulation of the endothelial isoform of nitric oxide synthase (eNOS) and concomitant downregulation of the endogenous inhibitor of eNOS, caveolin-1 (CAV-1). In this study we examined the effects of estrogen-independent eNOS upregulation (via simvastatin) and/or CAV-1 downregulation (antisense) on pial venular leukocyte adhesion in ovariectomized (OVX) rats. METHODS: Intact and OVX rats were prepared with closed cranial windows. Adherent rhodamine 6G-labeled leukocytes were viewed by intravital microscopy. To demonstrate the importance of pial venular eNOS in the resistance to leukocyte adhesion, intact female rats were treated with a nonselective (N(G)-nitro-L-arginine) or a neuronal NOS-selective (7-nitroindazole) inhibitor. In OVX females, leukocyte adhesion was compared in the following groups: (1) untreated; (2) treated with simvastatin; (3) treated with simvastatin plus CAV-1 antisense; (4) treated with simvastatin plus CAV-1 missense; (5) treated with CAV-1 antisense; and (6) treated with CAV-1 missense. RESULTS: In intact females, pial venular leukocyte adhesion was increased when total NOS activity, but not neuronal NOS activity alone, was blocked. In OVX rats, basal leukocyte adhesion, measured as the percentage of venular area occupied by adherent leukocytes, was attenuated (by approximately equal 60%) only in the presence of combined simvastatin plus CAV-1 antisense treatment. CONCLUSIONS: Present findings demonstrate that eNOS-derived NO plays an important role in limiting cerebral venular leukocyte adhesion in female rats. These data also suggest that simvastatin-induced upregulation of eNOS expression in OVX rats will not restore eNOS function, as measured by decreased leukocyte adhesion, unless CAV-1 levels are reduced as well.

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Simvastatin induces apoptosis of cultured rat cardiomyocytes.

Zimlichman R.

Cardiovascular and Hypertension Research Laboratory and Department of Medicine, The Institute of Physiologic Hygiene, Wolfson Medical Center, Holon, Israel. elanimgd inter.net.il

Considering the therapeutic effect of statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) and simvastatin in patients with coronary heart disease, our first hypothesis was that simvastatin should inhibit apoptosis (programmed cell death) in angiotensin II-treated cultured myocytes. But after realizing that simvastatin stimulates apoptosis, we changed our hypothesis and began to study its apoptotic effect in primary cultured rat cardiomyocytes. We found that simvastatin induced apoptosis in a dose-dependent manner (0.1 to 3 micromol/L), as evidenced by the appearance of increased DNA fragmentation in agarose gels and characteristic apoptotic patterns in nuclei labeled with Hoechst 33342, as well as increased activity of caspase 3. FACS analysis of simvastatin-treated cardiomyocytes showing annexin V binding and propidium iodide exclusion ruled out the possibility of necrosis. Increased intracellular enzymatic activity of creatine phosphokinase, aldolase, and lactic dehydrogenase, markers for normal cell function, could reflect the hypertrophic effect of simvastatin. The results indicate that simvastatin-induced apoptosis in cultured heart cells is concentration-dependent and additive to the apoptotic effect of angiotensin II.

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Simvastatin improves endothelial function in spontaneously hypertensive rats through a superoxide dismutase mediated antioxidant effect.

Marhuenda E.

Hypertension and Lipids Unit, Department of Internal Medicine, Virgen del Rocio University Hospital, Seville, Spain. jcarneado hvr.sas.cica.es

BACKGROUND : Hydroxymethylglutaryl coenzyme A (HMGCoA) reductase inhibitors have beneficial effects beyond their cholesterol-lowering properties. The antioxidant mechanism of HMGCoA reductase inhibitors is not completely understood. OBJECTIVES : To elucidate the antioxidant effect of simvastatin. METHODS : We studied the influence of simvastatin treatment on the development of hypertension, modification of antioxidant systems, and reactivity of aortic rings in Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. RESULTS : Simvastatin had no effect on blood pressure (BP). Simvastatin treatment (either 1 or 2 mg/kg body weight for 12 or 20 weeks) increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in SHR rats compared with untreated control SHR rats. Carbachol-induced relaxation of aortic rings was impaired in control SHR rats and was restored by simvastatin treatment. Addition of SOD improved the response in control SHR rats and did not have any effect in treated SHR rats. Addition of diethyldithiocarbamic acid, a selective inhibitor of SOD, produced a mild non-significant impairment in carbachol-induced relaxation in control SHR rats, suggesting a deficient antioxidant system in these animals. However, in treated SHR and in WKY rats, impairment of the relaxation was marked, implying that SOD activity in these animals was important to maintain endothelial function. In aortic rings without endothelium from SHR rats, contraction induced by free radicals was substantially higher than in WKY rats. This effect was attenuated in 1-mg-treated rats and abolished in 2-mg-treated rats. CONCLUSIONS : Simvastatin promotes intracellular antioxidant systems, fundamentally SOD, restoring endothelial function but not having any effect on blood pressure.

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[Inhibition of proliferation and induction of apoptosis by simvastatin in K562 leukemic cell line]

[Article in Chinese]

Lu D.

Institute of Hematology & People's Hospital, Peking University, Beijing 100044, China.

OBJECTIVE: To investigate the anti-apoptotic mechanism and explore approach to inhibiting proliferation and inducing apoptosis of chronic myclogenous leukemia (CML) cells. METHODS: K562 cell line was used to evaluate the effects of simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and the combination of simvastatin with chemotherapeutic agents on the proliferation and apoptosis of CML cells. RESULTS: Simvastatin could significantly inhibit proliferation and induce apoptosis of K562 cells, and could increase the sensitivity of K562 cells to chemotherapeutic agents. Addition of mevalonate, the immediate product of HMG-CoA, could completely reverse this effect. CONCLUSION: Simvastatin inhibited proliferation and induced apoptosis of K562 cells through inhibiting the metabolic pathway of mevalonate. It is promising that HMG-CoA reductase inhibitors may be an effective chemotherapeutic approach to the treatment of CML.

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