Relation between Baseline Lipid Levels and Effectiveness of HMG-CoA Reductase Inhibitors in Patients with Hyperlipidemia

Objective To evaluate whether the effects of HMG - CoA reductase inhibitors on patients with hyperlipidemia are closely related to baseline lipid levels. Methods The data analyzed originated from 3 separate multicenter clinical trials with similar designs during 1994 to 1999. 166 patients with mean age 58. 9±9. 2 years were involved in Simvastatin Clinical Trial with simvastatin 10 mg once daily for 8 weeks. 146 patients with mean age 57. 9±8. 7years were involved in Lovastatin Clinical Trial with lovastatin 20 mg once daily for 8 weeks. 105 patients with mean age 57. 8±9. 3 years were involved in Atorvastatin Clinical Trial with atorvastatin 10 mg once daily for 6 weeks. Baseline total cholesterol (TC) was more than 5. 98 mmol. L - 1, and baseline triglyceride (TG) was less than 4. 52 mmo. L - 1. The patients were grouped by baseline lipid levels. Results The higher the baseline TC, low density lipoprotein cholesterol (LDL - C) and TG levels were, the more effective the simvastatin, lovastatin, or atorvastatin was in reducing serum TC, LDL - C, and TG, respectively. A positive linear correlation was found between baseline values and effects of simvastatin, lovastatin, or atorvastatin in reducing serum TC, LDL - C, and TG, respectively. Conclusion The changes of reduction on serum lipid with HMG - CoA reductase inhibitors in patients with hyperlipidemia were influenced by baseline lipid levels.

INHIBITORY EFFECT OF FLUVASTATIN ON AORTIC INTIMAL THICKENING IN NORMOCHOLESTEROLEMIC RABBITS

The anti atherosclerotic effect of fluvastatin at doses insufficient to lower serum cholesterol on the catheter induced intimal thickening and possible mechanism were investigated in abdominal aorta of rabbits. Methods.Fifty six rabbits were randomly divided into eight groups(n=7,each).Fluvastatin was given mixed with food at daily dose of8mg/kg starting 5 days before catheterization.Light microscope,immunohistochemistry,transmission electron microscope and RT PCR assay were applied to assess vascular smooth muscle cell (VSMC)proliferation and apoptosis, as well as oncogene expression in vascular wall. Results.At day 10 and day 15 after catheter induced denudation intima/media(I/M)thickness ratio was obviously higher, and also the percentage of PCNA positive cells and TUNEL positive cells in media was significantly higher compared with controls.The intimal hyperplasia was mostly composed of α SM actin positive cells.In rabbits given fluvastatin I/M ratio and the percentage of these positive cells significantly decreased compared with those without fluvastatin.The overexpression of proto oncogene H ras mRNA and decreased expression of anti oncogene p53 mRNA were found after vascular injury,whereas fluvastatin significantly reduced H ras mRNA and increased p53 mRNA expression. Conclusion.Proliferation of VSMC in the media and the migration to the intima can be inhibited,and apoptosis of VSMC be induced by short term use of fluvastatin after balloon catheter denudation,independent of serum lipid change.The underlying mechanism is presumably associated with the influence of fluvastatin on oncogene expression in the injured vascular wall.

Synthesis of 4-phenoxy quinoline mevalonolactones and evaluation of their HMG CoA reductase inhibition activities

A series of 4-phenoxy quinoline-based mevalonolactone derivatives have been synthesized and evaluated as 3-hydroxy-3-methylglutaryl CoA reductase （HMG CoA reductase） inhibitors.One member of this series,（4R,6S）-6-{（E）-2-[6-fluoro-7-chloro-4-（4-fluorophenoxy-quinoline）-3-yl-]-ethenyl}-3,4,5,6-tetrahydro-4-hydroxy-2H-pyran-2-one （3d）,showed more potent activity than rosuvastatin or pitavastatin to inhibit the rat HMG CoA reductase in vitro.This compound was selected for the extensive preclinical development as a potential hypocholesterolemic candidate.

Statins and Breast Cancer: An Overview of the Current Situation

Statins [(3-hydroxy-3-methylglutaryl-coenzyme A reductase, HMG-CoA reductase, abbreviated HMGCR) inhibitors] inhibit cholesterol synthesis and are commonly used in the treatment and prevention of cardiovascular diseases. Preclinical and clinical studies have shown that the drug can be effective in several cancers including breast cancer which is the second most frequent cancer in the world and the commonest one among women. In breast cancer cell lines statins reduce proliferation, increase apoptosis, decrease invasion and sensitize them to radiation. Clinical trials in breast cancer patients have shown positive outcome in terms of decreased recurrence rate, decreased mortality and positive role as neoadjuvant agent. They may have a particular role in treatment-resistant cases like triple-negative or inflammatory breast cancer which have a poorer prognosis. There is also evidence of their potential use in metastatic bone disease from breast cancer. When statins inhibit 3-hydroxy-3-methylgutaryl CoA reductase which is the rate-limiting enzyme of the mevalonate pathway, the levels of mevalonate as well as its downstream products are decreased. Hence cancer growth is inhibited by reduced prenylation of CAAX proteins, N-Glycosylation of growth factor receptors and synthesis of membrane and steroid among others. Also statins are relatively cheap and can contribute to decrease the high cost of cancer treatment. However studies till now have not shown any association with decreased breast cancer incidence. In addition there are doubts regarding safety of statins when used over a prolonged period of time. Although statins are relatively safe with myotoxicity and hepatotoxicity being their major side effects, evidence regarding issues like drug interactions with anti-cancer drugs is lacking.

Statin as a therapeutic agent in gastroenterological cancer

Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase,the rate-limiting enzyme of the mevalonate pathway,and are widely used as an effective and safe approach handle hypercholesterolemia.The mevalonate pathway is a vital metabolic pathway that uses acetyl-CoA to generate isoprenoids and sterols that are crucial to tumor growth and progression.Multiple studies have indicated that statins improve patient prognosis in various carcinomas.Basic research on the mechanisms underlying the antitumor effects of statins is underway.The development of new anti-cancer drugs is progressing,but increasing medical costs from drug development have become a major obstacle.Readily available,inexpensive and well-tolerated drugs like statins have not yet been successfully repurposed for cancer treatment.Identifying the cancer patients that may benefit from statins is key to improved patient treatment.This review summarizes recent advances in statin research in cancer and suggests important considerations for the clinical use of statins to improve outcomes for cancer patients.

Lovastatin increases nitric oxide synthesis in IL-1β-stimulated smooth muscle cells

Objective Nitric oxide(NO)production by inducible NO synthase(Inos)may play an important role in the pathogenesis of atherosclerosis.Although lovastatin has been shown to reduce the progression of atherosclerosis,it is not known whether it regulates NO production.We investigated the effects of lovastatin on NO synthesis and the mechanisms by which lovastatin exerts its effects in rat vascular smooth muscle cells.Methods Primary cultures of the vascular smooth muscle cells were obtained from the media of the thoracic aorta of Sprague Dawley rats(200 - 250 g).Nitrite levels in the culture medium of rat vascular smooth muscle cells were determined colorimetrically.Results Lovastatin(10-5 mol/L)significantly increased interieukin-1β(IL-1β,10 ng/Ml)-induced nitrite accumulation in a time(0- 24 hours)-dependent manner.Exogenous mevalonate and geranylgeranylpyrophosphate completely reversed the stimulatory effects of lovastatin on nitrite production.Furthermore,inhibition of Rho by C3 exoenzyme mimicked the increase in IL-1β-induced nitrite accumulation induced by lovastatin in the vascular smooth muscle cells.Conclusion These results demonstrate that lovastatin up-regulates NO formation in rat vascular smooth muscle cells stimulated by IL-1β,and the effect may be associated with the inhibition of Rho activity.

Aspirin and pravastatin reduce lectin-like oxidized low density lipoprotein receptor-1 expression, adhesion molecules and oxidative stress in human coronary artery endothelial cells

Background Oxidative stress and inflammation are important steps in the pathogenesis of atherosclerosis. We postulated that therapeutic concentrations of aspirin and pravastatin, especially in combination, may suppress oxidative stress and inflammation in endothelial cells, and this concept was examined in human coronary artery endothelial cells （HCAECs）. Methods Human coronary artery endothelial cells were cultured and treated with oxidized-low density lipoprotein （ox-LDL, 60 ug/ml for 24 hours） alone, or pre-treated with aspirin （1, 2 or 5 mmol/L）, pravastatin （1, 5 or 10 umol/L） or their combination （1 mmol/L aspirin and 5umol/L pravastatin）, followed by ox-LDL treatment. After respective treatment, superoxide anion production, p38 mitogen activated protein kinase and transcription factor NF-KB activation, protein expression of lectin-like ox-LDL receptor-1 （LOX-1） and adhesion molecules, and monocyte adhesion were measured. Results Ox-LDL treatment greatly elicited its receptor LOX-1 expression, superoxide anion production and inflammatory response, which were minimally affected by low concentration of aspirin （1 mmol/L） or pravastatin （5umol/L）, but were markedly decreased by their combination. Activation of p38 mitogen activated protein kinase and NF-KB, the expression of intercellular adhesion molecule-1 and monocyte chemotactic protein-I, which were only mildly affected by aspirin or pravastatin alone, were significantly attenuated by their combination. As a consequence, monocyte adhesion to endothelial cells was markedly attenuated by the combination of the two agents. Well-known anti-oxidants a-tocopherol and y-tocopherol had similar inhibitory effects on ox-LDL-mediated oxidative stress and LOX-1 expression as well as monocyte adhesion as did the combination of aspirin and pravastatin. Conclusions These studies point to a positive interaction between aspirin and pravastatin with regard to endothelial bioloqy. Anti-oxidant and subsequent anti-inflammatory effect may be one of the potential underling mechanisms.