The effect of low-dose simvastatin in children with familial hypercholesterolaemia: a 1-year observation.

Widhalm K.

Department of Paediatrics, University of Vienna, Wahringer Gurtel 18-20, 1090, Austria.

Familial hypercholesterolaemia (FH) is a severe disorder of lipid metabolism associated with an enhanced risk to develop cardiovascular disease later in life, with atherosclerotic lesions beginning already in childhood. These are facts which make an early diagnosis and therapy necessary to prevent or delay such complications. The aim of this study was to investigate the efficacy and safety of low-dose simvastatin, a potent HMG-CoA reductase inhibitor, in children and adolescents with FH. Therefore, 20 children and adolescents (12 females, 8 males) aged between 10 and 17 years with FH were recruited for this 1-year simvastatin study. According to baseline levels of low density lipoprotein (LDL)-C, girls and boys were divided into two groups, one group (with LDL-C <220 mg/dl) starting with a simvastatin dosage of 5 mg/day, the other (with LDL-C >220 mg/dl) 10 mg/day with the possibility to increase dosages up to a daily maximum of 20 mg, if not reaching LDL-C concentrations of <170 mg/dl within the first period. Every 4-8 weeks, weight, height, lipids, Lp(a) and routine safety parameters of all participants were determined by a paediatrician, documenting exactly all side-effects. The percentage decrease was 25% for LDL-C in the 5 mg simvastatin period (19% for total cholesterol (tChol)), 30% for LDL-C in the 10 mg period (26% for tChol) and 36% decrease for LDL-C in the 20 mg period (29% for tChol). The changes for high density lipoprotein (HDL)-C were -5.9% (5 mg), +2.9% (10 mg) and -10.9% (20 mg) the percentage decrease in triglycerides was 12.6% (5 mg), 14.3% (10 mg) and 21% (20 mg). The side-effects of simvastatin were of no clinical relevance and all disappeared after a couple of days.CONCLUSION: our results showed that simvastatin seems to be an effective and safe medical therapy even in children and adolescents with familial hypercholesterolaemia.

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Simvastatin reduces infarct size in a model of acute myocardial ischemia and reperfusion in the rat.

Thiemermann C.

The William Harvey Research Institute, St. Bartholomew's and the Royal London School of Medicine, UK.

BACKGROUND: This study was designed to investigate the effects of simvastatin in a rat model of acute myocardial infarction. MATERIAL/METHODS: Male Wistar rats were anesthetized (thiopentone sodium 120 mg/kg). After a thoracotomy, the left-anterior-descending coronary artery (LAD) was occluded (for 25 min) and reperfused (for 120 min). Area at risk (AR) was determined with Evans Blue dye and infarct size after staining of the area at risk with nitroblue tetrazolium. RESULTS: In rats, which received the vehicle for simvastatin (10% DMSO, 1 ml/kg i.v. at 1 h prior to the occlusion of the LAD), occlusion of the LAD for 25 min followed by reperfusion for 2 hours resulted in an infarct size of 54 +/- 4% (n=7) of the AR. When compared with vehicle, administration of simvastatin (1 mg/kg i.v. bolus administration at 1 h prior to the onset of myocardial ischemia) caused a significant reduction in myocardial infarct size of 39%. LAD-occlusion and reperfusion caused a progressive fall in mean arterial blood pressure (when compared with sham-operated animals). Simvastatin had no significant effect on blood pressure. CONCLUSIONS: The result indicates that simvastatin, an inhibitor of HMG-CoA reductase and a ligand of PPAR-a and PPAR-g, reduces the tissue necrosis associated with acute myocardial infarction. We propose that statins may be useful in conditions associated with ischemia-reperfusion of the heart and other organs.

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Bcl-xL overexpression protects from apoptosis induced by HMG-CoA reductase inhibitors in murine tubular cells.

Egido J.

Renal and Vascular Research Laboratory, Division of Nephrology-Hypertension, Fundacion Jimenez Diaz,Universidad Autonoma Madrid, Madrid, Spain.

BACKGROUND: Hyperplasia is attributed to enhanced tubular cell proliferation with unbalanced cell death. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors induce apoptosis in a variety of cell lines, including proximal tubular cells. However, the mechanisms by which statins induce apoptosis in tubular cells have not been fully addressed. METHODS: Apoptosis induced by simvastatin was measured in murine tubular cells with and without overexpressing Bcl-xL. Expression of genes implicated in cell death was studied by Northern and Western blot. RESULTS: The treatment of proliferating murine tubular cells (MCT) with simvastatin induced apoptosis in a time- and dose-dependent manner (0.1 to 1 micromol/L). Apoptosis was correlated with Bcl-xL mRNA and protein down-regulation. By contrast, the treatment with simvastatin did not modify the expression of the proapoptotic protein Bax. Simvastatin treatment was associated with cytochrome C release from the mitochondria to the cytosol. We also observed the presence of active caspase 9 and 3 during apoptosis induced by simvastatin. These effects were reversed by mevalonate, farnesylpyrophosphate (FPP), and geranylgeranylpyrophosphate (GGPP), suggesting the involvement of protein prenylation. Simvastatin appears to alter the balance between cell-life and death-promoting genes, as reflected by the decreased Bcl-xL/Bax ratio. Supporting this hypothesis, overexpression of Bcl-xL reduced the amount of apoptosis induced by simvastatin by 80% when compared with control vector-expressing cells. The overexpression of Bcl-xL also prevented the activation of caspase 9 and 3. CONCLUSION: Our results indicate that down-regulation of Bcl-xL expression mediates apoptosis induced by statins in tubular cells. These results may be relevant to the treatment of disorders characterized by altered tubular proliferation.

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Mechanism of simvastatin on induction of heat shock protein in osteoblasts.

Kozawa O.

Department of Pharmacology, Gifu University School of Medicine, 40 Tsukasa-machi, Gifu-shi, Gifu-ken 500-8705, Japan.

It has recently been reported that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) stimulate bone formation. However, the mechanism of stimulation of bone metabolism by statins is not precisely clarified. In this study, we investigated whether simvastatin induces heat shock protein (HSP) 27, HSP70, and HSP90 in osteoblast-like MC3T3-E1 cells. Simvastatin increased the levels of HSP27 while having little effect on the levels of HSP70 or HSP90. The effect of simvastatin on HSP27 accumulation was dose dependent. Cycloheximide reduced the accumulation. Simvastatin induced an increase in the levels of mRNA for HSP27. Actinomycin D suppressed the mRNA levels. Simvastatin induced the phosphorylation of p38 mitogen-activated protein (MAP) kinase among the MAP kinase superfamily. SB203580 and PD169316, inhibitors of p38 MAP kinase, suppressed the HSP27 accumulation by simvastatin while SB202474, a negative control of p38 MAP kinase inhibitor, had no effect. SB203580 reduced the simvastatin-increased mRNA levels for HSP27. Lovastatin, another statin, also induced the HSP27 accumulation and SB203580 suppressed the HSP27 accumulation. These results strongly suggest that statins such as simvastatin do not stimulate the induction of HSP70 and HSP90, but do stimulate the induction of HSP27 in osteoblasts and that p38 MAP kinase plays a role in this induction.

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Simvastatin inhibits expression of tissue factor in advanced atherosclerotic lesions of apolipoprotein E deficient mice independently of lipid lowering: potential role of simvastatin-mediated inhibition of Egr-1 expression and activation.

Rosenfeld ME.

Department of Pathobiology, Box 353410, University of Washington, Seattle, WA 98195, USA.

Recent studies suggest that the beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in reducing cardiovascular events may in part, be independent of their capacity to lower plasma lipids. To test this hypothesis, simvastatin (50 mg/kg/d) was administered to 30-week-old apolipoprotein E deficient mice (apo E-/-) for 12, 18 and 24 weeks. In contrast to other experimental models and humans, simvastatin treatment increases plasma cholesterol levels in apo E-/- mice. Quantitative real-time polymerase chain reaction was used to quantify expression of tissue factor (TF) and monocyte chemoattractant protein-1 (MCP-1) in the aorta of each mouse. Expression of TF was reduced to 34, 24, and 13% of control levels at 12, 18 and 24 weeks, respectively, of simvastatin administration. Advanced lesions in the innominate arteries of the simvastatin treated mice had reduced levels of TF, fewer macrophages and reduced expression of early growth response-1 (Egr-1). In vitro studies in mouse macrophages demonstrated decreased lipopolysaccharide induced binding of nuclear proteins to the Egr-1 consensus DNA sequence following pretreatment with simvastatin. RNA levels for MCP-1 were reduced to 30% of control values following 24 weeks of simvastatin treatment. In conclusion, these data suggest that chronic administration of simvastatin to older apo E-/- mice can inhibit the expression of pro-thrombotic/pro-inflammatory genes within established atherosclerotic lesions via mechanisms that are independent of reductions in plasma lipids.

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Simvastatin inhibits interleukin-6 release in human monocytes stimulated by C-reactive protein and lipopolysaccharide.

Chen XJ.

Department of Cardiology, Renmin Hospital, Wuhan University School of Medicine, 238 JieFang Road, Wuhan 430060, People's Republic of China. lijnjn yahoo.com.cn

BACKGROUND: The accumulating evidence suggests that C-reactive protein (CRP) may have direct inflammatory effects on the vascular wall and that statin therapy may have important non-lipid anti-inflammatory effects confirmed by decreasing serum inflammatory markers, such as CRP. However, the effect of simvastatin on interleukin-6 (IL-6) release in cultured human monocytes was not investigated.DESIGN A prospective, human monocyte culture, simvastatin intervention study. METHODS: Monocytes were isolated from blood of healthy volunteers by the Ficoll density gradient and stimulated by broad concentrations of CRP (1-20 microg/ml) and lipopolysaccharide (LPS, 1-10 ng/ml) at indicated time points (0, 2, 4, 8, 16 and 24 h). Also 10-8-10-6 mol/l simvastatin was coincubated with cells in the presence of CRP and LPS. Measurements of IL-6 were performed from supernatants of cultured medium in duplicate, using a commercial assay kit. RESULTS: CRP and LPS induced the rapid release of IL-6, with significantly elevated levels in cultured supernatants at 4 h in the CRP group and at 2 h in the LPS group. The effects of CRP and LPS on IL-6 release of monocytes were dose and time dependent. A greater than 11-fold increase of IL-6 in the CRP group (20 microg/ml) and a greater than 26-fold increase in the LPS group (10 ng/ml) were observed at 24 h compared with the control group (945.7+/-98.3 pg/ml compared with 94.3+/-12.4 pg/ml and 1720.4+/-690.1 pg/ml compared with 70.1+/-16.7 pg/ml, P<0.001, respectively). However, 10-8-10-6 mol/l simvastatin inhibited significantly the production of IL-6 in monocytes stimulated by CRP and LPS in a dose-dependent manner, with the maximal inhibiting effect at a concentration of 10-6 mol/l (945.7+/-98.3 pg/ml compared with 180.9+/-31.2 pg/ml and 1720.4+/-690.1 pg/ml compared with 824.0+/-206.2 pg/ml, P<0.001 respectively). CONCLUSIONS: CRP and LPS could induce IL-6 release in human monocytes and simvastatin could inhibit this response in a dose-dependent manner, which may provide an insight into the mechanisms of anti-inflammatory or anti-atherosclerotic actions of simvastatin.

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