Pharmacological effects of HMG CoA reductase inhibitors other than lipoprotein modulation

Statin Therapy May not Effect NLR and MPV Levels in Patients With Hypercholesterolemia: A Retrospective Study

Statins may exert pleiotropic effects in coronary artery disease (CAD), diabetes mellitus, and familial hypercholesterolemia. We evaluated the effects of statins on the neutrophil-lymphocyte ratio (NLR) and mean platelet volume (MPV) in 261 consecutive patients with hypercholesterolemia having CAD or at high cardiovascular (CV) risk and 50 healthy participants who were retrospectively included in this study. Patients were treated with 10 to 80 mg atorvastatin or 10 to 40 mg rosuvastatin for 24 weeks according to baseline levels of cholesterol, triglycerides, and CV risk. Baseline NLR and MPV were significantly higher in patients with CAD or at high risk compared to the control group (1.89 [0.37-6.78]) vs 1.44 [0.75-2.41], P < .001 and 8.8 [6.27-18.6] vs 8.45 [6-11] fL, P = .038, respectively). The NLR, MPV, and lipid parameters were also compared in the patient group after statin treatment for 24 weeks. Lipid levels decreased but the NLR and MPV did not change significantly after the statin therapy. Further studies are needed to clarify the effect of statin therapy on NLR and MPV in patients with CAD or at high CV risk.

Administration of simvastatin after kainic acid-induced status epilepticus restrains chronic temporal lobe epilepsy

In this study, we examined the effect of chronic administration of simvastatin immediately after status epilepticus (SE) on rat brain with temporal lobe epilepsy (TLE). First, we evaluated cytokines expression at 3 days post KA-lesion in hippocampus and found that simvastatin-treatment suppressed lesion-induced expression of interleukin (IL)-1β and tumor necrosis factor-α (TNF-α). Further, we quantified reactive astrocytosis using glial fibrillary acidic protein (GFAP) staining and neuron loss using Nissl staining in hippocampus at 4-6 months after KA-lesion. We found that simvastatin suppressed reactive astrocytosis demonstrated by a significant decrease in GFAP-positive cells, and attenuated loss of pyramidal neurons in CA3 and interneurons in dentate hilar (DH). We next assessed aberrant mossy fiber sprouting (MFS) that is known to contribute to recurrence of spontaneous seizure in epileptic brain. In contrast to the robust MFS observed in saline-treated animals, the extent of MFS was restrained by simvastatin in epileptic rats. Attenuated MFS was related to decreased neuronal loss in CA3 and DH, which is possibly a mechanism underlying decreased hippocampal susceptibility in animal treated with simvastatin. Electronic encephalography (EEG) was recorded during 4 to 6 months after KA-lesion. The frequency of abnormal spikes in rats with simvastatin-treatment decreased significantly compared to the saline group. In summary, simvastatin treatment suppressed cytokines expression and reactive astrocytosis and decreased the frequency of discharges of epileptic brain, which might be due to the inhibition of MFS in DH. Our study suggests that simvastatin administration might be a possible intervention and promising strategy for preventing SE exacerbating to chronic epilepsy.

In Vitro and In Vivo Effects of Statins on Platelet-Activating Factor and Its Metabolism

Platelet activating factor (PAF) is implicated in cardiovascular disease (CVD). Statins are widely used in these situations. Therefore, we assessed their effect on the biological activities and metabolism of PAF. Several statins, including simvastatin, exhibited an inhibitory effect against PAF, comparable with that of PAF-inhibitors. Simvastatin also suppressed in vivo PAF-biosynthesis via the de novo pathway, in leukocytes of 6 simvastatin-treated volunteers. Total cholesterol and low-density lipoprotein cholesterol were also significantly decreased, whereas high-density lipoprotein cholesterol, triacylglycerol, EC50, and lag time were unaffected in these participants. Simvastatin with an intact lactone ring also inhibited PAF-activities, while incubation of human mesangial cells with it also resulted in decreased de novo PAF-biosynthesis. This suggests that these simvastatin-dependent effects are independent of its lactone ring. These new actions of statins should be further studied in PAF-implicated pathological conditions such as CVD, cancer, and renal disease.

Long-term benefits after treatment of traumatic brain injury with simvastatin in rats

OBJECTIVE

This study was designed to investigate the long-term effects of simvastatin treatment after traumatic brain injury (TBI) in rats.

METHODS

Adult female Wistar rats (n = 24) were injured with controlled cortical impact and divided into 3 groups. The first 2 groups were treated with simvastatin (0.5 or 1.0 mg/kg) administered orally for 14 days starting 1 day after TBI. The third group (control) received phosphate-buffered saline orally for 14 days. Neurological functional outcome was measured with modified neurological severity scores performed 1 day before TBI; on days 1, 4, 7, 14 after TBI; and biweekly thereafter. All animals were sacrificed 3 months after TBI. Brain tissues of half of the animals were processed for preparation of paraffin-embedded sections for immunohistological studies. The remaining half were frozen for enzyme-linked immunosorbent assay studies for quantification of brain-derived neurotrophic factor (BDNF) in the hippocampus and cortex.

RESULTS

The results showed that both doses of simvastatin significantly improved functional outcome compared with the control, with no difference between the 2 doses. Simvastatin treatment of 1.0 mg/kg increased the number of morphologically intact neurons in the hippocampus, but treatment of 0.5 mg/kg had no significant effect. Enzyme-linked immunosorbent assay studies showed that 0.5 mg/kg simvastatin significantly increased BDNF levels within the hippocampus, but 1.0 mg/kg had no significant effect. Neither dose had any effect on BDNF levels within the cortex.

CONCLUSION

Simvastatin treatment provides long-lasting functional improvement after TBI in rats. It also enhances neuronal survival in the hippocampus and increases BDNF levels in the hippocampus secondary to simvastatin treatment.

Lipophilic but not hydrophilic statins selectively induce cell death in gynaecological cancers expressing high levels of HMGCoA reductase

Recent reports have suggested that statins induce cell death in certain epithelial cancers and that patients taking statins to reduce cholesterol levels possess lower cancer incidence. However, little is known about the mechanisms of action of different statins or the effects of these statins in gynaecological malignancies. The apoptotic potential of two lipophilic statins (lovastatin and simvastatin) and one hydrophilic statin (pravastatin) was assessed in cancer cell lines (ovarian, endometrial and cervical) and primary cultured cancerous and normal tissues. Cell viability was studied by MTS assays and apoptosis was confirmed by Western blotting of PARP and flow cytometry. The expressions of key apoptotic cascade proteins were analysed. Our results demonstrate that both lovastatin and simvastatin, but not pravastatin, selectively induced cell death in dose- and time-dependent manner in ovarian, endometrial and cervical cancers. Little or no toxicity was observed with any statin on normal cells. Lipophilic statins induced activation of caspase-8 and -9; BID cleavage, cytochrome C release and PARP cleavage. Statin-sensitive cancers expressed high levels of HMG-CoA reductase compared with resistant cultures. The effect of lipophilic statins was dependent on inhibition of enzymatic activity of HMG-CoA reductase since mevalonate pre-incubation almost completely abrogated the apoptotic effect. Moreover, the apoptotic effect involved the inhibition of synthesis of geranylgeranyl pyrophosphate rather than farnesyl pyrophosphate. In conclusion, lipophilic but not hydrophilic statins induce cell death through activation of extrinsic and intrinsic apoptotic cascades in cancerous cells from the human female genital tract, which express high levels of HMG-CoA reductase. These results promote further investigation in the use of lipophilic statins as anticancer agents in gynaecological malignancies.

The effect of statins on the development of new-onset type 2 diabetes: a meta-analysis of randomized controlled trials

OBJECTIVE

To determine the ability of statins to prevent the development of new-onset type 2 diabetes mellitus through a meta-analysis of randomized, controlled trials.

RESEARCH DESIGN AND METHODS

A systematic literature search through November 6, 2007 was conducted to identify randomized, placebo-controlled trials of statins that reported data on the incidence of new-onset diabetes mellitus. Incidence of new-onset type 2 diabetes mellitus was treated as a dichotomous variable. Weighted averages were reported as relative risk (RR) with associated 95% confidence intervals (CI). A random-effects model was used.

RESULTS

Five prospective, randomized controlled trials (n = 39,791) were identified. Upon meta-analysis, the use of a statin did not significantly alter a patient's risk of developing new-onset type 2 diabetes mellitus (relative risk, 1.03; 95% confidence interval 0.89-1.19). Subgroup and sensitivity analyses did not significantly change the results. There was statistical heterogeneity that stemmed from pravastatin's tendency towards a reduction in risk and the other statins showing an increase in risk. The funnel plot could not rule out publication bias.

CONCLUSIONS

Statins, as a class, do not demonstrate a statistically significant positive or negative impact on a patient's risk of developing new-onset type 2 diabetes mellitus.

Raynaud's Phenomenon in Mixed Connective Tissue Disease

Raynaud's phenomenon affects most patients who have mixed connective tissue disease (MCTD) and frequently represents the initial manifestation of the disease. It is the cutaneous symptom of a systemic vasculopathy that is characterized by intimal fibrosis and blood vessel obliteration that frequently leads to visceral involvement, particularly pulmonary hypertension. An association between Raynaud's phenomenon and the characteristic autoantibody in MCTD, anti-U1-RNP (ribonucleoprotein), is found across the spectrum of rheumatic diseases, including undifferentiated connective tissue disease, scleroderma, and systemic lupus erythematosus. Capillary nailfold examination represents a valuable tool to identify patients who are at risk for MCTD. The goal in the therapy of Raynaud's phenomenon in MCTD is to decrease the frequency of attacks, to prevent digital ulceration, and to limit progressive vascular damage. Therapeutic regimens include the traditional use of calcium channel blockers and novel vascular therapies.

The effect of HMG-CoA reductase inhibitors on chronic allograft rejection

Hydroxy-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors have pleiotropic actions that affect many systems other than lowering blood cholesterol concentrations. Hypercholesterolaemia is an adverse effect of immunosuppressive drug therapy and hence it is a common finding after organ transplantation. HMG-CoA reductase inhibitors lower cholesterol concentrations in transplant recipients but they also offer additional benefits. Since they impair the production of mevalonate, they reduce the concentrations of downstream products including farnesyl and geranyl phosphate. These isoprenoid moieties are required for protein prenylation and HMG-CoA reductase inhibitors impair this function in some cells. This action affects the immune system, especially in patients taking cyclosporin, and has been proposed as the mechanism whereby these drugs increase the half-life of transplanted organs. Other mechanisms have also been proposed including an increase in the free fraction of cyclosporin and a reduction in the time that low density lipoprotein (LDL) spends in blood. The latter effect reduces the extent of oxidation of LDL and hence reduces the damage caused by oxidised LDL. Chronic rejection is poorly understood but appears to involve both immune and non-immune processes. HMG-CoA reductase inhibitors affect both processes. At present, the evidence of benefit from statin prescription is confined to heart and kidney transplant recipients but it is likely that recipients of other organ transplants would also benefit. Drug interactions between cyclosporin and HMG-CoA reductase inhibitors are a limiting factor to their use. Pravastatin appears to be the best HMG-CoA reductase inhibitor for organ transplant recipients because of its lesser potential to interact with cyclosporin and hence cause myositis, which may thus allow higher doses to be used. Other, non-immunosuppressive drugs (including diltiazem and ketoconazole) have been shown to reduce transplant organ damage by unknown mechanisms and are widely prescribed in some transplant centres. More specific inhibitors of protein prenylation may afford useful immunosuppression, thereby prolonging transplant organ half-lives and also reducing the risk of cancer.

Atheroma stabilizing effects of simvastatin due to depression of macrophages or lipid accumulation in the atheromatous plaques of coronary plaque-prone WHHL rabbits

Clinical studies showed that both hydrophilic and lipophilic statins reduce coronary events although in vitro studies demonstrated that lipophilic statins inhibited proliferation of arterial smooth muscle cells. Therefore, we examined whether lipophilic simvastatin reduces smooth muscle cells in atheromatous plaque and how simvastatin affects stability of atheroma in vivo. Coronary atherosclerosis-prone WHHLCA rabbits aged 10 months were given simvastatin (15 mg/kg) orally for 52 weeks and examined the serum lipid levels, plasma drug concentration, and aortic and coronary atherosclerosis. Compared to the placebo group, the plasma cholesterol levels decreased by about 20%. In the simvastatin group, the lipid component (macrophages+extracellular lipids) was decreased in the coronary and aortic atheroma, despite no decrease in the fibromuscular components. Consequently, the frequency of vulnerable plaque decreased. In the coronary plaque of the simvastatin group, PCNA-positive cells (which appeared to be macrophages) of the plaques decreased but the TUNEL-positive cells did not show significant change. Finally, fully differentiated smooth muscle cells increased in the aortic lesions of the simvastatin group. In conclusion, our results suggest that simvastatin did not depress the fibromuscular components in atheromatous plaques and the plaque-stabilizing effects were due to the reduction of macrophages/lipid deposits.

Statin initiation following coronary artery bypass grafting: outcome of a hospital discharge protocol

STUDY OBJECTIVES

To evaluate the outcome of a hospital discharge statin drug therapy initiation protocol following coronary artery bypass graft (CABG) surgery. Our goal was to measure the percentage of patients receiving statin drugs at hospital discharge and at a post-hospital discharge assessment following the implementation of the statin drug therapy initiation protocol. We also evaluated low-density lipoprotein cholesterol (LDL-C) goal attainment (ie, < 100 mg/dL), safety monitoring, and tolerability of the statin drug.

DESIGN

Single-center, observational study with a historical control group.

SETTING

University-affiliated health system with a comprehensive heart care program that included a 14-bed cardiac surgery ICU. Approximately 400 CABG procedures are performed annually.

PATIENTS

Patients who underwent CABG surgery were eligible for inclusion in the study. The exclusion criteria were as follows: contraindications to statin therapy; refusal to take a statin drug; refusal to give informed consent; and age < 18 years.

INTERVENTION

A protocol was implemented to recommend treatment with a statin drug at hospital discharge in all post-CABG surgery patients if the presurgical LDL-C level was > 100 mg/dL or the patient was receiving a statin prior to hospital admission. The protocol also included a presurgical assessment of lipoprotein levels and hepatic function. All cardiac surgery staff were educated regarding the specifics of the protocol.

RESULTS

A total of 403 patients were included in the study. The historical control group (202 subjects) and the intervention group (201 subjects) were similar with respect to gender, age, and baseline lipoprotein levels. The follow-up assessment interval was approximately 6 months in both groups. Overall, patients were more likely to receive a statin at hospital discharge in the intervention group compared to the control group (relative risk [RR], 1.6; 95% confidence interval [CI], 1.3 to 2.0). Attainment of the goal for LDL-C level was similar between the intervention and control groups in the overall sample. Patients who were not at their LDL-C goal at baseline were more likely to have a follow-up LDL-C level of < 100 mg/dL in the intervention group (RR, 1.9; 95% CI, 1.0 to 3.5). The rate of liver function assessment was similar in the control and intervention groups. No patients in either group experienced elevations of alanine aminotransferase levels that were more than three times the upper limit of normal, and no cases of muscle toxicity were noted.

CONCLUSION

The initiation of therapy with a statin drug at hospital discharge following CABG surgery was associated with increased utilization rates. The LDL-C goal attainment improved in patients who were not at their goal prior to surgery. However, the persistence of medication use declined within 6 months. Statin therapy initiation was well-tolerated in this cohort of patients.

Statins as coronary vasodilators in isolated bovine coronary arteries--involvement of PGI2 and NO

Here we studied direct vasodilation induced by statins in isolated bovine coronary arteries. In rings of coronary bovine arteries preconstricted with prostaglandin F(2 alpha) (3 x 10(-8) - 10(-5)), lovastatin, simvastatin, atorvastatin and cerivastatin (3-30 microM) but not pravastatin induced concentration-dependent vasodilation. Removal of endothelium diminished response to simvastatin, cerivastatin and atorvastatin (30 microM) (67.4+/-4.56 vs. 22.7+/-8.14%, 96.9+/-2.27% vs. 54.5+/-6.86%, 67.4+/-4.01% vs. 34.6+/-5.66%, respectively). In presence of L-NAME (300 microM) or indomethacin (5 microM) responses to simvastatin, atorvastatin and cerivastatin, were also partially diminished. In contrast, lovastatin-induced vasorelaxation was not significantly affected by removal of endothelium (35.6+/-4.19% vs. 28.8+/-5.24%) or by pretreatment with L-NAME or indomethacin. In summary, with the exception of pravastatin, statins act as coronary vasodilators. Simvastatin, cerivastatin and atorvastatin but not lovastatin induced vasodilation displayed endothelium dependent- and endothelium-independent components. The endothelium-dependent effect of statins was mediated by NO and PGI(2), while the mechanism of smooth muscle cells-dependent component remains to be determined.

Delayed Thrombosis after Traumatic Brain Injury in Rats

Secondary thrombosis may contribute to cerebral ischemia caused by traumatic brain injury (TBI). In this study, we sought to investigate the temporal and spatial profiles of intravascular thrombosis and to evaluate the effect of atorvastatin, a beta-hydroxy-beta-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitor, on thrombosis after TBI. Young male Wistar rats weighing 350-400 g were subjected to controlled cortical impact injury, and were sacrificed at 1 and 4 h, and 1, 3, 8, and 15 days after TBI (5 rats/time point), respectively. For the evaluation of the effects of atorvastatin on intravascular thrombosis, rats were subjected to TBI, and subsequently atorvastatin (1 mg/kg) was orally administered starting 1 day after TBI and then daily until sacrifice at 3, 8, and 15 days after TBI (5 rats/time point). Before sacrifice of animals, blood was withdrawn and employed for the measurement of von Willibrand factor and platelet activity using enzyme-linked immunoabsorbant assay (ELISA). Brain tissues were prepared for histological analysis. The data show that (1) delayed thrombosis is present in the lesion boundary zone and in the hippocampal CA3 region, starting at 1-4 h, peaking at 1-3 days, and then declining at 8 and 15 days after TBI; (2) intravascular thrombosis also occurs in the other areas of cortex, striatum, and corpus callosum, but with a scattered distribution; (3) delayed thrombi are composed of platelets, fibrin, and vWF; and (4) reduction of the plasma vWF level and platelet activity by atorvastatin decreases delayed thrombosis after TBI. These data suggest that atorvastatin reduces intravascular thrombosis attributed to hemostatic disturbances caused by TBI.

Cerivastatin-induced apoptosis of human aortic smooth muscle cells through partial inhibition of basal activation of extracellular signal-regulated kinases

BACKGROUND

The beneficial effects of cerivastatin including hypolipidemic properties have been demonstrated to involve nonlipid as well as lipid mechanisms. In the present study, we examined the mechanisms underlying cerivastatin-induced growth inhibition of human aortic smooth muscle (ASM) cells.

METHODS

Human ASM cells were cultured in 96-well plates with or without cerivastatin in the presence or absence of mitogen-activated protein (MAP) kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase MEK1/MEK 2 inhibitor PD98059. Cell growth was assessed by colorimetric quantitation of NADH, and cell viability was determined by trypan blue dye exclusion method. The induction of apoptosis was determined by propidium iodide (PI) staining method using flow cytometer. The activation of ERKs or c-Jun N-terminal kinases (JNKs) was determined by Western blotting using antibodies (Abs) specific for phospho-ERKs or phospho-JNKs.

RESULTS

Treatment of the ASM cells with cerivastatin prevented cell growth in a concentration-dependent manner through at least induction of apoptosis. The cerivastatin-induced apoptosis was reversed by coincubation with isoprenoid [mevalonate, geranylgeranyl pyrophosphate (GGPP), and farnesyl pyrophosphate (FPP)] suggesting a role for isoprenoid in the cerivastatin-induced apoptosis. The cerivastatin cooperated with a MEK1/MEK2 inhibitor PD98059 to induce apoptosis, which appeared to correlate with down-regulation of ERK activation (phospho-ERKs expression) induced by the combination.

CONCLUSION

Cerivastatin-induced blockade of ERK activation in ASM cells might result in growth inhibition including apoptosis, which might explain some aspects of the beneficial effects of cerivastatin on coronary artery disease.

Lipid-altering changes and pleiotropic effects of atorvastatin in patients with hypercholesterolemia

In this prospective study, we found beneficial short-term effects from atorvastatin therapy, including effects on low-density lipoprotein subfractions and remnant-like lipoprotein particle cholesterol, antioxidant effects, and alterations in endothelial function that may be important in early benefit from statin therapy; some effects would support much earlier benefit than previously reported. We also found long-term effects of atorvastatin, including decreased plasminogen activator inhibitor type-1 and additional significant alterations in low-density lipoprotein subfractions and endothelial function, supporting benefits from continuous long-term atorvastatin therapy beyond early reversal of hypercholesterolemia.

Differential effects of simvastatin and atorvastatin on high-density lipoprotein cholesterol and apolipoprotein A-I are consistent across hypercholesterolemic patient subgroups

BACKGROUND

In addition to lowering plasma levels of low-density lipoprotein cholesterol (LDL-C), statins also raise high-density lipoprotein cholesterol (HDL-C).

HYPOTHESIS

Recent studies have shown that treatment with simvastatin results in larger increases in HDL-C than those seen with atorvastatin. The results of three clinical studies are analyzed, comparing the effects of simvastatin and atorvastatin on HDL-C and apolipoprotein A-I (apo A-I) in the total cohort and in several subgroups of hypercholesterolemic patients. The three studies were all multicenter, randomized clinical trials that included simvastatin (20-80 mg) and atorvastatin (10-80 mg) treatment arms. The subgroup analyses performed were gender; age (< 65 and > or = 65 years); baseline HDL-C (male: < 40 or > or = 40 mg/dl; female: < 45 or > or = 45 mg/dl), baseline LDL-C (< 160 or > or = 160 mg/dl), and baseline triglycerides (< 200 or > or = 200 mg/dl).

RESULTS

Both drugs produced similar increases in HDL-C levels at low doses; however, at higher drug doses (40 and 80 mg), HDL-C showed a significantly greater increase with simvastatin than with atorvastatin (p < 0.05 to < 0.001). Therefore, while HDL-C remained consistently elevated across all doses of simvastatin, there appeared to be a pattern of decreasing HDL-C with an increasing dose of atorvastatin. A similar negative dose response pattern was also observed with apo A-I in atorvastatin-treated patients, suggesting a reduction in the number of circulating HDL particles at higher doses. Both drugs reduced LDL-C and triglycerides in a dose-dependent fashion, with atorvastatin showing slightly greater effects. The differential effects of atorvastatin and simvastatin on HDL-C and apo A-I were observed for both the whole study cohorts and all subgroups examined; thus, no consistent treatment-by-subgroup interactions were observed.

CONCLUSION

The data presented show that, across different hypercholesterolemic patient subgroups, simvastatin increases HDL-C and apo A-I more than atorvastatin at higher doses, with evidence of a negative dose response effect on HDL-C and apo A-I with atorvastatin, but not simvastatin.

Lovastatin extended release: a review of its use in the management of hypercholesterolaemia

Lovastatin extended release (ER) provides a new form of delivery for lovastatin, an HMG-CoA reductase inhibitor. Lovastatin ER delivers the drug in a more sustained fashion, as shown by a smoother plasma concentration-time profile, a lower maximum plasma concentration and a prolonged half-life compared with that of lovastatin immediate release (IR). At dosages of 10-60 mg/day, lovastatin ER significantly reduced levels of total cholesterol, low density lipoprotein (LDL)-cholesterol and triglycerides, and increased levels of high density lipoprotein-cholesterol, in patients with primary hypercholesterolaemia in a randomised, double-blind study of 12 weeks' duration. These effects were maintained in a 6-month extension study in which patients received lovastatin 40 or 60 mg/day. In a randomised 4-week study in 24 patients with primary hypercholesterolaemia, the reduction in plasma LDL-cholesterol levels was significantly greater with lovastatin ER 40 mg/day than with the IR formulation administered at the same dosage. Lovastatin ER was well tolerated in all studies and adverse events were usually mild to moderate and transient. The tolerability profile of lovastatin ER was similar to that of lovastatin IR. There were no reports of clinically relevant elevations in liver transaminases or creatine phosphokinase attributed to the drug in recipients of lovastatin ER.

CONCLUSION

The ER formulation of lovastatin provides smooth and sustained delivery of this established and well-tolerated agent over the dosage interval, significantly reducing LDL-cholesterol in patients with primary hypercholesterolaemia. If, as expected, the beneficial changes in lipid levels are maintained during long-term treatment and further clinical experience confirms the greater efficacy of the lovastatin ER formulation than the IR formulation, then lovastatin ER is likely to supplant lovastatin IR and provide a useful option in the management of patients with dyslipidaemia and prevention of coronary heart disease.

The combination of nebivolol plus pravastatin is associated with a more beneficial metabolic profile compared to that of atenolol plus pravastatin in hypertensive patients with dyslipidemia: a pilot study

Nebivolol, a selective beta1-lipophilic blocker, achieves blood pressure control by modulating nitric oxide release in addition to b-blockade. This dual mechanism of action could result in minimum interference with lipid metabolism compared to atenolol, a classic beta1-selective blocker. Hypertensive patients commonly exhibit lipid abnormalities and frequently require statins in combination with the anti-hypertensive therapy. We conducted this trial in order to clarify the effect on the metabolic profile of beta-blocker therapy with atenolol or nebivolol alone, or in conjunction with pravastatin. Thirty hypertensive hyperlipidemic men and women (total cholesterol >240 mg/dL [6.2 mmol/L], low-density lipoprotein cholesterol >190 mg/dL [4.9 mmol/L], triglycerides <500 mg/dL [5.6 mmol/L]) were separated in two groups. One group consisted of 15 subjects on atenolol therapy (50 mg daily), and the other group included 15 subjects on nebivolol therapy (5 mg daily). After 12 weeks of beta-blocker therapy, pravastatin (40 mg daily) was added in both groups for another 12 weeks. Atenolol significantly increased triglyceride levels by 19% (P=.05), while nebivolol showed a trend to increase high-density lipoprotein cholesterol by 8% (NS) and to decrease triglyceride levels by 5% (NS). Atenolol significantly increased lipoprotein(a) by 30% (P=.028). Fibrinogen levels were equally and not significantly decreased in both groups by 9% and 7%, respectively. Furthermore, atenolol and nebivolol decreased serum high-sensitivity C-reactive protein levels by 14% (P=.05) and 15% (P=.05), respectively. On the other hand, both atenolol and nebivolol showed a trend to increase homocysteine levels (NS) by 13% and 11%, respectively. Although uric acid levels remained the same, atenolol significantly increased the fractional excretion of uric acid by 33% (P=.03). Following nebivolol administration, glucose levels remained the same, while insulin levels were reduced by 10% and the HOMA index (fasting glucose levels multiplied by fasting insulin levels and divided by 22.5) was reduced by 20% (P=.05). There were no significant differences between the two patient groups in the measured parameters after the administration of beta-blockers, except for triglycerides (P<.05) and the HOMA index (P=.05). The addition of pravastatin to all patients (n=30) decreased total cholesterol by 21% (P<.001), low-density lipoprotein cholesterol by 28% (P<.001), apolipoprotein-B by 22% (P<.001), apolipoprotein-E by 15% (P=.014) and lipoprotein(a) levels by 12% (P=.023). Moreover, homocysteine levels and C-reactive protein were reduced by 17% (P=.05) and 43% (P=.05), respectively. We conclude that nebivolol seems to be a more appropriate therapy in hypertensive patients with hyperlipidemia and carbohydrate intolerance. Finally, the addition of pravastatin could further correct the well-established predictors of cardiovascular events.

Management of Raynaud's phenomenon and digital ischemic lesions in scleroderma

Raynaud's phenomenon is a challenging problem in patients who have scleroderma. It causes a great deal of morbidity with recurrent painful attacks and frequent digital ischemic lesions. The strategy to treat the vascular disease must consider treatment for the vasospasm and the intrinsic vascular disease with intimal proliferation and vessel occlusion. Vasodilator therapy remains the main method to treat Raynaud's phenomenon, but new understanding of the pathobiology of scleroderma vascular disease is providing novel treatment options. We need more investigations into these vasoactive drugs before routine use can be recommended. Critical ischemia can cause deep tissue injury and digital loss. An aggressive approach to reversing an ischemic crisis is essential for preventing these severe events.

Effect of HMG-CoA reductase inhibitors on proliferation and protein synthesis by rat hepatic stellate cells

BACKGROUND/AIMS

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors called statins, have besides their cholesterol-lowering function, therapeutic value in conditions such as neo-angiogenesis and atherosclerosis. We investigated the effect of two statins on the proliferation rate and protein steady state levels of hepatic stellate cells (HSC).

METHODS

Cellular DNA synthesis under the influence of statins and/or platelet derived growth factor (PDGF) and mevalonate was evaluated by measuring BrdU incorporation. Synthesis of collagens type I, III, IV and fibronectin was quantified by ELISA. Additionally, we examined the influence of simvastatin on isoprenylation of Ras and RhoA proteins.

RESULTS

Lovastatin and simvastatin induced a dose-dependent inhibition of the proliferation rate of HSC. Subsequent addition of PDGF and/or mevalonate, after long-term exposure of simvastatin to HSC, did not reverse simvastatins' antiproliferative effect. Lovastatin and simvastatin reduced the protein steady state level of collagens type I (-40%), III (-45%) and IV (-27%). Membrane bound Ras steady state levels decreased under the influence of simvastatin. Membrane bound RhoA remained unaltered, whereas, cytosolic RhoA protein level was strongly reduced.

CONCLUSIONS

Our data showed that lovastatin and simvastatin inhibited HSC proliferation and collagen steady state levels by mechanisms independent of their lipid reducing activities.

Effects of Atorvastatin Therapy on the Low-Density Lipoprotein Subfraction, Remnant-Like Particles Cholesterol, and Oxidized Low-Density Lipoprotein Within 2 Weeks in Hypercholesterolemic Patients

The short- and intermediate-term pleiotropic effects of atorvastatin were investigated in 18 hypercholesterolemic patients, as well as the temporal differences in these pleiotropic effects. Atorvastatin was given for 3 months and fasting lipid concentrations, thiobarbituric acid reactive substances (TBARS), fibrinolytic parameters, and flow-mediated dilation of the brachial artery (FMD) were measured at baseline and after 2 weeks and 3 months of therapy. Atorvastatin reduced the total cholesterol (273+/-34 vs 188+/-31 mg/dl, p<0.0001), low-density lipoprotein-cholesterol (LDL-C: 174+/-28 vs 111+/-23 mg/dl, p<0.0001), small, dense LDL-C (34+/-22 vs 18+/-20%, p<0.01), remnant-like particles cholesterol (RLP-C: 8.8+/-6.0 vs 5.1+/-2.6 mg/ml, p<0.01), and TBARS (3.3+/-1.0 vs 3.1+/-0.9 nmol/ml, p<0.05) after 2 weeks. Atorvastatin decreased the concentration of small, dense LDL-C again after 3 months (8+/-13%, p<0.0001). The plasma concentrations of the fibrinolytic parameters did not change significantly after 3 months of atorvastatin therapy. FMD increased significantly after 2 weeks (5.6+/-2.1 vs 6.3+/-2.0%, p<0.01) and additionally increased after 3 months of therapy (8.3+/-1.9%, p<0.0001). There were no correlations between the pleiotropic effects and the improvement in the lipid profile. The results indicate some short-term pleiotropic effects of atorvastatin therapy within 2 weeks, which may be important with respect to the early benefits of statin therapy.

Regulation of CYP2B6 and CYP3A expression by hydroxymethylglutaryl coenzyme A inhibitors in primary cultured human hepatocytes

The effects of treatment with the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) inhibitors lovastatin, simvastatin, pravastatin, fluvastatin, and atorvastatin on the contents of cytochrome p450 mRNAs were examined in primary cultures of human hepatocytes prepared from three different livers. Treatment of 2- to 3-day-old human hepatocyte cultures with 3 x 10(-5) M lovastatin, simvastatin, fluvastatin, or atorvastatin for 24 h increased the amounts of CYP2B6 and CYP3A mRNA by an average of 3.8- to 9.2-fold and 24- to 36-fold, respectively. In contrast, pravastatin treatment had no effect on the mRNA level of either CYP2B6 or CYP3A, although treatment with pravastatin did produce the expected compensatory increase in HMG-CoA reductase mRNA content, indicating effective inhibition of cholesterol biosynthesis. Although treatment with the active (+), but not the inactive (-), enantiomer of atorvastatin increased the amount of HMG-CoA reductase mRNA, treatment with each enantiomer significantly induced both CYP2B6 and CYP3A mRNA levels. Treatment of primary cultured rat hepatocytes with the atorvastatin enantiomers effectively increased the amount of CYP3A mRNA, but had no effect on CYP2B or CYP4A mRNA levels, in contrast to fluvastatin, which increased both. Findings for p450 proteins by Western blotting were consistent with the mRNA results. These findings indicate that the ability of a drug to inhibit HMG-CoA reductase activity does not predict its ability to produce p450 induction in primary cultured human hepatocytes, and demonstrate that some, but not all, of the effects of these drugs that occur in primary cultured rat hepatocytes are conserved in human hepatocyte cultures.

Distribution of cyclosporin in organ transplant recipients

Cyclosporin is an immunosuppressive agent with a narrow therapeutic index. The total concentration of cyclosporin in blood is usually monitored to guide dosage adjustment and to compensate for substantial interindividual and intraindividual variability in cyclosporin pharmacokinetics. Cyclosporin is a highly lipophilic molecule and widely distributes into blood, plasma and tissue components. It mainly accumulates in fat-rich organs, including adipose tissue and liver. In blood, it binds to erythrocytes in a saturable fashion that is dependent on haematocrit, temperature and the concentration of plasma proteins. In plasma, it binds primarily to lipoproteins, including high-density, low-density and very-low-density lipoprotein, and, to a lesser extent, albumin. The unbound fraction of cyclosporin in plasma (CsA(fu)) expressed as a percentage is approximately 2%. It has been shown that both the pharmacokinetic and pharmacodynamic properties of cyclosporin are related to its binding characteristics in plasma. Furthermore, there is some evidence to indicate that the unbound concentration of cyclosporin (CsA(U)) has a closer association with both kidney and heart allograft rejection than the total (bound + unbound) concentration. However, the measurement of CsA(fu) is inherently complex and cannot easily be performed in a clinical setting. Mathematical models that calculate CsA(fu), and hence CsA(U), from the concentration of plasma lipoproteins may be a more practical option, and should provide a more accurate correlate of effectiveness and toxicity of this drug in transplant recipients than do conventional monitoring procedures. In conclusion, the distribution characteristics of cyclosporin in blood, plasma and various tissues are clinically important. Further investigations are needed to verify whether determination of CsA(U) improves the clinical management of transplant recipients.

Mechanisms of inhibitory effects of cerivastatin on rat vascular smooth muscle cell growth

The aim of this study was to clarify the mechanism(s) of an inhibitory effect of cerivastatin on cultured rat vascular smooth muscle cell (VSMC) growth. After being starved, cultured VSMCs were stimulated by 5% fetal bovine serum with either various concentrations of cerivastatin or 10-4 M of mevalonate. Cerivastatin dose-dependently decreased the values of [3H]-thymidine incorporation and cell numbers and the level of phosphorylated extracellular signal-regulated protein kinase 1/2. It also suppressed the level of proliferative cell nuclear antigen in a dose-dependent manner. These reductions were abolished by the addition of mevalonate. Similarly, the level of phosphorylated p38 was also decreased by cerivastatin. In contrast, cerivastatin dose-dependently activated the phosphorylation of both c-jun NH2-terminal protein kinase and activating transcription factor-2, and these activations were abolished by the addition of mevalonate. The levels of phosphorylated Akt and p70 S6 kinase as well as those of Bcl-2 were dose-dependently reduced by cerivastatin, and these reductions were abolished by the addition of mevalonate. Cerivastatin could dose-dependently elevate the levels of CPP32/caspase-3 activity and cytoplasmic histone-associated DNA fragments in VSMCs without causing cytotoxicity. These results indicate that cerivastatin suppresses cell survival and activates the apoptotic cellular signaling in VSMCs, suggesting that it could be effective for preventing the progression of restenosis after angioplasty.

Cerivastatin-induced rhabdomyolysis: 11 case reports

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors are a frequently prescribed class of drugs that are generally well tolerated by most patients. A rare, yet serious side effect associated with these drugs is rhabdomyolysis. Although all HMG-CoA reductase inhibitors can cause this adverse effect, prevalence may differ among specific agents. Over a 16-month period, in three hospitals, 11 patients experienced cerivastatin-induced rhabdomyolysis, but no cases of rhabdomyolysis associated with any other HMG-CoA reductase inhibitors were reported.

The effects of hydroxy-methyl-glutaryl co-enzyme A reductase inhibitors on platelet thrombus formation

BACKGROUND

Hydroxy-methyl-glutaryl co-enzyme A reductase inhibitors (HMG CoA RIs) markedly improve the lipid profile of patients with hypercholesterolemia, but the magnitude and time course of the effect of these drugs on other risk factors for atherosclerosis are not well defined.

METHODS

We employed a random assignment, double-blind design to compare the effect of 8 weeks of HMG CoA RI therapy with either pravastatin (40 mg QD; n=12) or simvastatin (20 mg QD; n=12) with placebo (n=13) on serum lipids, platelet thrombus formation (PTF), and markers of inflammation and thrombosis in patients with coronary artery disease. PTF was measured using a validated ex vivo perfusion chamber system.

RESULTS

Total and LDL cholesterol decreased 20.3 +/- 12.7% and 31.4 +/- 16.5% in the HMG CoA RI group and were unchanged with placebo (P<0.01). Triglycerides also decreased 15.3 +/- 22.5% with HMG CoA RI therapy, but increased 8.4 +/- 30.0% with placebo (P=0.01). PTF increased 54.1 +/- 89.0% with placebo and decreased 8.0 +/- 46.82% with HMG CoA RI treatment (P<0.01).

CONCLUSIONS

HMG CoA RI therapy with pravastatin or simvastatin reduces PTF after only 8 weeks of therapy. Such lipid effects may contribute to the prompt reduction in cardiovascular events noted in some clinical trials.

Fibromuscular cap composition is important for the stability of established atherosclerotic plaques in mature WHHL rabbits treated with statins

We examined the relationship between plaque vulnerability and fibromuscular cap composition using hydrophilic pravastatin and lipophilic fluvastatin. WHHL rabbits aged 10 months were given pravastatin (50 mg/kg) or fluvastatin (20 mg/kg) for 52 weeks. The atherosclerotic lesions were immunohistochemically or conventionally stained and the components were analyzed with a color image analyzer. Compared with the control group, the plasma cholesterol levels were decreased by about 25% in both statin groups. Pravastatin decreased the lipid components (macrophages+extracellular lipids) in whole aortic plaques by 34% and the fibrous caps of coronary plaques by 55%. Fluvastatin decreased the fibromuscular components (smooth muscle cells+collagen fibers) in whole aortic plaques and in the fibromuscular caps of the aortic and coronary plaques. In the pravastatin group, the vulnerability index, the ratio of (lipid components)/(fibromuscular components), was decreased in whole aortic plaques by 28% and in the fibromuscular caps of coronary lesions by 61%, while the indexes were increased in the fluvastatin group. The incidence of vulnerable plaques was decreased by 74% in the coronary plaques of the pravastatin group. Our results suggest that the stability of atheromatous plaques was improved due to a decrease of the lipid components and vulnerability index of the fibromuscular cap by pravastatin.

Cerivastatin: a review of its pharmacological properties and therapeutic efficacy in the management of hypercholesterolaemia

Cerivastatin is an HMG-CoA reductase inhibitor used for the treatment of patients with hypercholesterolaemia. The lipid-lowering efficacy of cerivastatin has been demonstrated in a number of large multicentre, randomised clinical trials. Earlier studies used cerivastatin at relatively low dosages of < or =0.3mg orally once daily, but more recent studies have focused on dosages of 0.4 or 0.8 mg/day currently recommended by the US Food and Drug Administration (FDA). Along with modest improvements in serum levels of triglycerides and high density lipoprotein (HDL)-cholesterol, cerivastatin 0.4 to 0.8 mg/day achieved marked reductions in serum levels of low density lipoprotein (LDL)-cholesterol (33.4 to 44.0%) and total cholesterol (23.0 to 30.8%). These ranges included results of a pivotal North American trial in almost 1000 patients with hypercholesterolaemia. In this 8-week study, US National Cholesterol Education Program (Adult Treatment Panel II) [NCEP] target levels for LDL-cholesterol were achieved in 84% of patients randomised to receive cerivastatin 0.8 mg/day, 73% of those treated with cerivastatin 0.4 mg/day and <10% of placebo recipients. Among patients with baseline serum LDL-cholesterol levels meeting NCEP guidelines for starting pharmacotherapy, 75% achieved target LDL-cholesterol levels with cerivastatin 0.8 mg/day. In 90% of all patients receiving cerivastatin 0.8 mg/day, LDL-cholesterol levels were reduced by 23.9 to 58.4% (6th to 95th percentile). Various subanalyses of clinical trials with cerivastatin indicate that the greatest lipid-lowering response can be expected in women and elderly patients. Cerivastatin is generally well tolerated and adverse events have usually been mild and transient. The overall incidence and nature of adverse events reported with cerivastatin in clinical trials was similar to that of placebo. The most frequent adverse events associated with cerivastatin were headache, GI disturbances, asthenia, pharyngitis and rhinitis. In the large pivotal trial, significant elevations in serum levels of creatine kinase and transaminases were reported in a small proportion of patients receiving cerivastatin but not in placebo recipients. As with other HMG-CoA reductase inhibitors, rare reports of myopathy and rhabdomyolysis have occurred with cerivastatin, although gemfibrozil or cyclosporin were administered concomitantly in most cases. Postmarketing surveillance studies in the US have been performed. In 3 mandated formulary switch conversion studies, cerivastatin was either equivalent or superior to other HMG-CoA reductase inhibitors, including atorvastatin, in reducing serum LDL-cholesterol levels or achieving NCEP target levels. Pharmacoeconomic data with cerivastatin are limited, but analyses conducted to date in the US and Italy suggest that cerivastatin compares favourably with other available HMG-CoA reductase inhibitors in terms of its cost per life-year gained.

CONCLUSION

Cerivastatin is a well tolerated and effective lipid-lowering agent for patients with hypercholesterolaemia. When given at dosages currently recommended by the FDA in the US, cerivastatin achieves marked reductions in serum levels of LDL-cholesterol, reaching NCEP target levels in the vast majority of patients. Thus, cerivastatin provides a useful (and potentially cost effective) alternative to other currently available HMG-CoA reductase inhibitors as a first-line agent for hypercholesterolaemia.

Clinical pharmacokinetics of cerivastatin

Cerivastatin sodium, a novel statin, is a synthetic, enantiomerically pure, pyridine derivative that effectively reduces serum cholesterol levels at microgram doses. Cerivastatin is readily and completely absorbed from the gastrointestinal tract, with plasma concentrations reaching a peak 2 to 3 hours postadministration followed by a monoexponential decay with an elimination half-life (t1/2beta) of 2 to 3 hours. Cerivastatin pharmacokinetics are linear: maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) are proportional to the dose over the range of 0.05 to 0.8 mg. No accumulation is observed on repeated administration. Cerivastatin interindividual variability is described by coefficients of variation of approximately 30 to 40% for its primary pharmacokinetic parameters AUC, Cmax and t1/2beta. The mean absolute oral bioavailability of cerivastatin is 60% because of presystemic first-pass effects. Its pharmacokinetics are not influenced by concomitant administration of food nor by the time of day at which the dose is given. Age, gender, ethnicity and concurrent disease also have no clinically significant effects. Cerivastatin is highly bound to plasma proteins (>99%). The volume of distribution at steady state of about 0.3 L/kg indicates that the drug penetrates only moderately into tissue; conversely, preclinical studies have shown a high affinity for liver tissue, the target site of action. Cerivastatin is exclusively cleared via metabolism. No unchanged drug is excreted. Cerivastatin is subject to 2 main oxidative biotransformation reactions: demethylation of the benzylic methyl ether moiety leading to the metabolite M-1 [catalysed by cytochrome P450 (CYP) 2C8 and CYP3A4] and stereoselective hydroxylation of one methyl group of the 6-isopropyl substituent leading to the metabolite M-23 (catalysed by CYP2C8). The product of the combined biotransformation reactions is a secondary minor metabolite, M-24, not detectable in plasma. All 3 metabolites are active inhibitors of hydroxymethylglutaryl-coenzyme A reductase with a similar potency to the parent drug. Approximately 70% of the administered dose is excreted as metabolites in the faeces, and 30% in the urine. Metabolism by 2 distinct CYP isoforms renders cerivastatin relatively resistant to interactions arising from inhibition of CYP. If one of the pathways is blocked, cerivastatin can be effectively metabolised by the alternative route. In addition, on the basis of in vitro investigations, there is no evidence for either cerivastatin or its metabolites having any inducing or inhibitory activity on CYP. The apparent lack of any clinically relevant interactions with a variety of drugs commonly used by patients in the target population supports this favourable drug-drug interaction profile.

Management of hypercholesterolemia

Benefit from the treatment of hyperlipidemia has now been conclusively documented, and this article has focused on the clinical trial data supporting diet and drug therapy in adult patients with different lipoprotein disorders and discussed therapeutic approaches with a focus on reducing plasma concentrations of LDL cholesterol. National guidelines for the use of hypolipidemic drugs are strongly supported by the clinical trials and have appropriately set lower target concentrations of LDL cholesterol for patients with established atherosclerosis or diabetic patients as compared with patients with more than two cardiovascular risk factors or, the lowest risk group, patients without evidence of atherosclerosis and fewer than two known cardiovascular risk factors. The goals of therapy in patients with established atherosclerosis are to prevent further progression and potentially induce regression, whereas in high-risk patients (e.g., those with heterozygous familial hypercholesterolemia) without evidence of atherosclerosis, the aims of therapy are to reduce LDL cholesterol to a concentration at which subclinical atherosclerosis and xanthomas regress and the patient does not develop premature cardiovascular disease. Evidence-based medicine strongly supports clinical benefit from the treatment of hypercholesterolemia in men and women with and without known coronary artery disease, and the main goal should be ensure that patients who could benefit from lipid-lowering therapy are effectively treated and followed to ensure long-term compliance, efficacy, and safety.