New insights into the pharmacodynamic and pharmacokinetic properties of statins

Combined organ failure with combination antihyperlipidemic treatment: a case of hepatic injury and acute renal failure

OBJECTIVE

To report a case of acute hepatic injury and acute renal failure secondary to rhabdomyolysis associated with fluvastatin-gemfibrozil combination therapy for hyperlipidemia.

CASE SUMMARY

A 56-year-old woman with a history of hyperlipidemia presented with fatigue, weakness in her lower extremities, and red-colored urine. One month prior, she had started combination therapy of fluvastatin 80 mg/day and gemfibrozil 1200 mg/day. On physical examination, she had a serious loss of motor function in the upper and lower extremities. Her laboratory tests revealed severe liver enzyme elevation and abnormal renal function. Abdominal ultrasound did not show hepatic cholestasis, renal parenchymal abnormality, or obstruction.

DISCUSSION

Statins and fibric acid derivatives have complementary effects on mixed hyperlipidemia. However, such combination therapy increases the risk of myopathy, which may result in life-threatening rhabdomyolysis. Several reports have suggested that combination fluvastatin-gemfibrozil therapy is both effective and safe in mixed lipid disorders. In our patient, severe rhabdomyolysis with serious hepatocellular injury was observed one month after the combination antihyperlipidemic therapy was started. Assessment with the Naranjo probability scale determined that an adverse drug reaction was probable. The mechanism of this combined toxicity is difficult to clarify, although in vivo and in vitro studies to date have reported considerable data concerning antihyperlipidemic drug interactions.

CONCLUSIONS

Clinicians should carefully consider the risks and benefits of treating dyslipidemia with fluvastatin-gemfibrozil combination therapy.

Therapy to reduce risk of coronary heart disease

Recent primary and secondary intervention studies have shown that reduction of low-density lipoprotein cholesterol (LDL-C) with statins significantly reduced coronary heart disease (CHD) morbidity and mortality. However, many patients with dyslipidemia who have or are at risk for CHD do not reach target LDL-C goals. The recently updated National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III guidelines identify a group of patients at very high risk for CHD for more aggressive LDL-C reduction and reaffirm the importance of high-density lipoprotein cholesterol (HDL-C) by raising the categorical threshold to 40 mg/dl. Lipid-lowering therapy needs to be more aggressive in both primary and secondary prevention settings, and therapy should be considered to increase HDL-C as well as lower LDL-C in order to improve patient outcomes. Both combination therapy and the next generation of statins may provide improved efficacy across the dyslipidemia spectrum.

Growth inhibition of Candida species and Aspergillus fumigatus by statins

Statins are a class of drugs widely used for lowering high cholesterol levels through their action on 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in the synthesis of cholesterol. We studied the effects of two major statins, simvastatin and atorvastatin, on five Candida species and Aspergillus fumigatus. The statins strongly inhibited the growth of all species, except Candida krusei. Supplementation of Candida albicans and A. fumigatus with ergosterol or cholesterol in aerobic culture led to substantial recovery from the inhibition by statins, suggesting specificity of statins for the mevalonate synthesis pathway. Our findings suggest that the statins could have utility as antifungal agents and that fungal colonization could be affected in those on statin therapy.

Alzheimer disease--no target for statin treatment. A mini review

Nosologically, Alzheimer disease (AD) is not a single disorder. A minority of around 400 families worldwide can be grouped as hereditary in origin, whereas the majority of all Alzheimer cases (approx. 25 million worldwide) are sporadic in origin. In the pathophysiology of the latter type, a number of susceptibility genes contribute to the disease among which are allelic abnormalities of the apolipoprotein E4 gene pointing to a link between disturbed cholesterol metabolism and sporadic AD. Cholesterol is a main component of membrane composition enriched in microdomains and is functionally linked to the proteolytic processing of amyloid precursor protein (APP). In sporadic AD, a marked diminution of both membrane phospholipids and cholesterol has been found. Evidence has been provided that high plasma cholesterol may protect from AD. In contrast to these well documented abnormalities observed in AD patients, it was assumed that an elevated cholesterol concentration might favour the generation of beta-amyloid and, thus, AD. However, a series of in vitro-and in vivo-studies did not provide evidence for the assumption that an enhanced cholesterol concentration increased betaA4-production. A harsh reduction of membrane cholesterol only caused a "beneficial" effect of APP metabolism. However, this experimentally induced condition may not be compatible to sporadic AD. The application of statins in sporadic AD did not yield results to assume that this therapeutic strategy may prevent or treat successfully sporadic AD.

Effects of chronic treatment with statins and fenofibrate on rat skeletal muscle: a biochemical, histological and electrophysiological study

BACKGROUND AND PURPOSE

Skeletal muscle injury by hypolipidemic drugs is not fully understood. An extensive analysis of the effect of chronic treatment with fluvastatin (5 mgkg(-1) and 20 mgkg(-1)), atorvastatin (10 mgkg(-1)) and fenofibrate (60 mgkg(-1)) on rat skeletal muscle was undertaken.

EXPERIMENTAL APPROACH

Myoglobinemia as sign of muscle damage was measured by enzymatic assay. Histological and immunohistochemical techniques were used to estimate muscle integrity and the presence of aquaporin-4, a protein controlling water homeostasis. Electrophysiological evaluation of muscle Cl(-) conductance (gCl) and mechanical threshold (MT) for contraction, index of intracellular calcium homeostasis, was performed by the two-intracellular microelectrodes technique.

KEY RESULTS

Fluvastatin (20 mgkg(-1)) increased myoglobinemia. The lower dose of fluvastatin did not modify myoglobinemia, but reduced urinary electrolytes, suggesting direct effects on renal function. Atorvastatin also increased myoglobinemia, with slight effects on urinary parameters. No treatment caused any histological damage to muscle or modification in the number of fibres expressing aquaporin-4. Either fluvastatin (at both doses) or atorvastatin reduced sarcolemma gCl and changed MT. Both statins produced slight effects on total cholesterol, suggesting that the observed modifications occur independently of HMGCoA-reductase inhibition. Fenofibrate increased myoglobinemia and decreased muscle gCl, whereas it did not change the MT, suggesting a different mechanism of action from the statins.

CONCLUSIONS AND IMPLICATIONS

This study identifies muscle gCl and MT as early targets of drugs action that may contribute to milder symptoms of myotoxicity, such as muscle cramps, while the increase of myoglobinemia is a later phenomenon.

Atorvastatin: beyond lipid-lowering effects in the diabetic population

Statins are the mainstay of therapy in coronary artery disease and hypercholesterolemia. Atorvastatin is a 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitor that is taken once daily. It has been shown to considerably reduce cardiovascular mortality events. Recently, several trials have demonstrated that atorvastatin has pleiotropic effects beyond its lipid-lowering capacities. Atorvastatin is especially beneficial in diabetics for stroke prevention and improving cardiovascular mortality risk.

Discontinuation of statin treatment in stroke patients

BACKGROUND AND PURPOSE

Statins reduce the risk for myocardial infarctions and stroke which may in part depend on cholesterol-independent (pleiotropic) vasoprotective effects. Here, we review evidence to suggest that the abrupt discontinuation of statin medication exerts negative vascular effects in patients with acute vascular events.

SUMMARY OF REVIEW

It is increasingly recognized that statins (HMG-CoA reductase inhibitors) exert rapid cholesterol-independent effects. Cessation of statin treatment confers overshoot activation of heterotrimeric G-proteins Rho and Rac causing production of reactive oxygen species and suppression of NO bioavailability. In humans, discontinuation of statin therapy leads to a proinflammatory, prothrombotic state with impaired endothelium function. In patients with acute coronary syndromes, abrupt discontinuation of statin therapy significantly increases morbidity and mortality, whereas in stable vascular patients discontinuation may be safe. Recent prospective data indicated that the cessation of statin medication in acute ischemic stroke patients confers a significantly higher likelihood of early neurological deterioration and poor outcome.

CONCLUSIONS

We propose that in all acute ischemic stroke patients chronically treated with statins before the event, treatment should be continued and the patient should receive medication at the day of the stroke.

Proteomic Study of Plasma from Moderate Hypercholesterolemic Patients

Proteomics is a technology to detect and identify several proteins and their isoforms in a single sample. We used proteomics to analyze modifications in the protein map of plasma after simvastatin treatment of moderate hypercholesterolemic patients. Plasma from hypercholesterolemic patients (n = 9) was compared before and after 12 weeks of simvastatin treatment (40 mg/day). Patients with similar cardiovascular risk factors were used as controls (CR group). By using two-dimensional electrophoresis and mass spectrometry, we identified the different protein isoforms. The plasma expression of three fibrinogen gamma chain isoforms (FGG) was enhanced, whereas the expression of two isoforms of the fibrinogen beta chain (FGB) was reduced in the hypercholesterolemic patients compared with the CR group. The expression of apolipoprotein A-IV and three haptoglobin isoforms was higher in hypercholesterolemic patients. Simvastatin treatment modified the plasma expression of FGG chain isoform 1, FGB chain isoforms 1 and 2, vitamin D binding protein isoform 3, apo A-IV, and haptoglobin isoform 2. The modification of FGG chain isoform 1 and FGB chain isoforms 1 and 2 was positively correlated with total plasma cholesterol level. Proteomic analysis of plasma may help to know more in depth the molecular mechanism modified by simvastatin treatment.

A pharmacoepidemiology study of the interaction between atorvastatin and clopidogrel after percutaneous coronary intervention

BACKGROUND

After percutaneous coronary intervention (PCI), the antiplatelet drug clopidogrel is frequently used to prevent stent thrombosis. A concern has been raised that atorvastatin may competitively inhibit the metabolism of the prodrug clopidogrel to its active metabolites by the cytochrome P450 3A4 (CYP3A4) enzyme, thereby potentially negating its antiplatelet effect. The 30-day rates of adverse cardiovascular events (composite of death, myocardial infarction, 11 unstable angina, stroke or transient ischemic attack, and repeat revascularization procedures) in unselected 12 patients prescribed clopidogrel after PCI as a function of their exposure to CYP3A4 inhibitors has not been fully resolved.

METHODS

Using the administrative databases from the Province of Québec, we identified all patients in 1999 and 2000 who received an outpatient prescription for clopidogrel within 5 days of PCI with stenting. Using multiple logistic regression, we compared the odds ratios (OR) of the composite cardiovascular outcome within 30 days of the index PCI between patients prescribed drugs inhibiting CYP3A4 activity and those who were not. Event rates were adjusted for demographic variables, disease severity, associated comorbidities, and other medications.

RESULTS

The 2927 patients who were prescribed clopidogrel after PCI were included in our cohort. Of these, 727 were prescribed atorvastatin and 2200 were not. There were 33 (4.54%) adverse events in the group prescribed atorvastatin and 68 (3.09%) in the group not prescribed atorvastatin. The adjusted 30-day OR of the composite outcome was 1.65 (95% CI 1.07-2.54) in patients prescribed atorvastatin with clopidogrel compared to those not prescribed atorvastatin. Other drugs that are substrates for CYP3A4 (OR 1.56, 95% CI 1.02-2.37) and a delay in filling the clopidogrel prescription (OR 1.77, 95% CI 1.16-2.70) were also associated with a higher risk. Sex, previous hospitalizations for unstable angina or myocardial infarction, aspirin use, or a history of revascularization (PCI or coronary artery bypass graft) in the 6 months before the index procedure was not statistically associated with adverse outcomes.

CONCLUSIONS

After coronary stenting, a delay in filling the prescription for clopidogrel as well as prescriptions for drugs inhibiting CYP3A4 enzyme activity was associated with adverse cardiovascular events. However, because of the limitations of observational study designs, the clinical significance of these putative drug interactions remains uncertain but merits further investigation.

Safety Issues with Statin Therapy

OBJECTIVE

To describe the most important potential adverse effects related to statin therapy, discuss mechanisms of toxicity and drug interactions, and suggest approaches for enhancing safety with statin therapy.

DATA SOURCES

Large-scale clinical trials, government databases and papers, and recent studies of statin safety.

STUDY SELECTION

By the author.

DATA EXTRACTION

By the author.

DATA SYNTHESIS

The number of patients requiring intensive therapy with statins to achieve lipid goals is climbing, and as the number grows, so does the potential for adverse effects with these agents. The most detrimental adverse effects of statins are hepatotoxicity and myopathy. Liver dysfunction induced by statins is rare and usually mild, with asymptomatic transaminase elevation or acute cholecystitis. Progression to liver failure is exceedingly rare, and transaminase elevations is usually reversible with dose reduction. Statin-associated myopathy is generally a concern when patients have more than one risk factor for muscle syndromes, such as an elderly patient with poor renal function. Drug interactions represent an additional concern, especially for atorvastatin, lovastatin, and simvastatin, all of which are metabolized by the important 3A4 isoenzyme of the cytochrome P450 system of the liver.

CONCLUSION

The benefits of all available statins for the treatment or prevention of cardiovascular disease outweigh any potential risks of therapy. For patient groups most susceptible to adverse effects, such as the elderly and those on multiple medications, clinicians should consider the use of statins that are least likely to interact with other medications.

Use of cryopreserved human hepatocytes in sandwich culture to measure hepatobiliary transport

Fresh hepatocytes cultured in a sandwich configuration allow for the development of intact bile canaliculi and the ability to measure hepatic uptake and biliary clearance. A disadvantage of this model is its dependence upon hepatocytes from fresh tissue. Therefore, the ability to use cryopreserved human hepatocytes in this model would be a great advantage. Multiple variables were tested, and the recommended conditions for culturing cryopreserved human hepatocytes in a sandwich configuration in 24-well plates are as follows: BioCoat plates, a cell density of 0.35 x 10(6) cells/well in 500 microl, an overlay of Matrigel and InVitroGRO media. These conditions resulted in good hepatocyte morphology and the formation of distinct bile canaliculi. The function of multiple uptake and efflux transporters was tested in multiple lots of cryopreserved and fresh human hepatocytes. For taurocholate [Na+ taurocholate cotransporting polypeptide/organic anion transporting polypeptide (OATP) uptake/bile salt export pump efflux], the average apparent uptake, apparent intrinsic biliary clearance, and biliary excretion index among five cryopreserved hepatocyte lots was high, ranging from 11 to 17 pmol/min/mg protein, 5.8 to 10 microl/min/mg protein, and 41 to 63%, respectively. The corresponding values for digoxin (OATP-8 uptake/multidrug resistance protein 1 efflux) were 0.69 to 1.5 pmol/min/mg protein, 0.60 to 1.5 microl/min/mg protein, and 37 to 63%. Both substrates exhibited similar results when fresh human hepatocytes were used. In addition, substrates of breast cancer resistance protein and multidrug resistance-associated protein 2 were also tested in this model, and all cryopreserved lots showed functional transport of these substrates. The use of cryopreserved human hepatocytes in 24-well sandwich culture to form intact bile canaliculi and to exhibit functional uptake and efflux transport has been successfully demonstrated.

Statin-induced proinflammatory response in mitogen-activated peripheral blood mononuclear cells through the activation of caspase-1 and IL-18 secretion in monocytes

Statins, which inhibit 3-hydroxy-3-methylglutaryl CoA reductase, have been shown recently to promote proinflammatory responses. We show in this study that both atorvastatin and simvastatin induced proinflammatory responses in mitogen-activated PBMCs by increasing the number of T cells secreting IFN-gamma. This is abolished by the presence of mevalonate, suggesting that statins act specifically by blocking the mevalonate pathway for cholesterol synthesis to promote the proinflammatory response. Both statins at low concentrations induced a dose-dependent increase in the number of IFN-gamma-secreting T cells in mitogen-activated PBMCs, whereas at higher concentrations the effect was abolished. The proinflammatory effect of statins was not seen in purified T cells per se activated with mitogen. However, conditioned medium derived from statin-treated PBMCs enhanced the number of IFN-gamma-secreting cells in activated purified T cells. This effect was not blocked by mevalonate, but was abolished by neutralizing Abs to IL-18 and IL-12. Similarly, the up-regulation of IFN-gamma-secreting T cells in PBMCs costimulated with statins and mitogens was blocked by the neutralizing anti-IL-18 and anti-IL-12. We showed that simvastatin stimulates the secretion of IL-18 and IL-1beta in monocytes. Active caspase-1, which is required for the processing and secretion of IL-18 and IL-1beta, was activated in simvastatin-treated monocytes. This was blocked by mevalonate and the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone. Taken together, the proinflammatory response mediated by statins in activated PBMCs is mediated mainly via the activation of caspase-1 and IL-18 secretion in the monocytes and to a lesser extent by IL-12.

Use of an indirect effect model to describe the LDL cholesterol-lowering effect by statins in hypercholesterolaemic patients

Statins are the most commonly prescribed agents for the treatment of hypercholesterolaemia. This is due to their efficacy in reducing low-density lipoprotein cholesterol (LDL) level which is the primary goal of the treatment especially for patients with multiple risk factors or with established coronary heart diseases. The purpose of this study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model that describes the LDL-lowering process in patients with hypercholesterolaemia treated with atorvastatin, fluvastatin or simvastatin. A total of 100 patients were studied retrospectively. They received atorvastatin (n = 57), fluvastatin (n = 26) or simvastatin (n = 17). As no pharmacokinetic data were available, the absorption rate was fixed to 1/h and atorvastatin, simvastatin and fluvastatin elimination half-lives were fixed to 14, 2 and 2.5 h respectively. A total of 309 LDL levels were measured and the data were analysed by nonmem v. The time course of the LDL-lowering effect of statins was described by an indirect-response model with precursor (LDL synthesis, input rate K(in)) and response (circulating LDL, input and output rates K) compartments. The following parameters were estimated: LDL input rate (K(in)) 0.14 +/- 0.015 g/L/day (mean +/- SD); inhibition fraction of K(in) (INH) 0.21 +/- 0.017; and dose producing 50% increase of LDL removal (D50), 26 +/- 7.8, 1.3 +/- 0.48 and 15 +/- 5.25 mg for atorvastatin, simvastatin and fluvastatin, respectively. Gender, bodyweight, age, calories/day, sugar/day, lipids/day, hyperlipidaemia types and waist/hip circumference, renal and hepatic functions had no effect on the pharmacodynamic parameters. The pharmacodynamic parameters for the three statins were accurately estimated. The PK/PD model developed successfully predicted the time course of the LDL-lowering effect of statins.

Safety and effects on the lipid and C-reactive protein plasma concentration of the association of ezetimibe plus atorvastatin in renal transplant patients treated by cyclosporine-A: a pilot study

Ezetimibe (E) is a new cholesterol adsorption inhibitor which prevents the adsorption of dietary and biliary cholesterol by binding to a recently described cholesterol transporter. This pilot study was performed to evaluate the safety and the low-density lipoprotein (LDL)-C and C-reactive protein lowering efficacy of atorvastatin (A) and of the association of A plus E in five renal transplant patients with hypercholesterolemia and mild renal functional impairment receiving cyclosporine-A (CsA). Patients received for three periods, each of 3 weeks, A at a dose of 20 mg/day; A at a dose of 10 mg/day and finally, A 10 mg plus E 10 mg daily. The medications were well-tolerated and no important clinical or laboratory (muscle enzyme, creatinine clearance and CsA concentration) abnormalities were observed throughout the study period. A alone lead to target LDL-C values only in two of five patients and did not significantly reduce the mean CRP values. The combination of E plus A produced the lowest lipid levels and significantly reduced CRP mean values and allowed all patients to attain target levels of LDL-C: total cholesterol decreased from 240 +/- 42 (mean +/- S.D.) to 171 +/- 34 mg/dl, LDL-C from 129 +/- 32 to 87 +/- 21 mg/dl, plasma triglycerides from 330 +/- 54 to 194 +/- 71 mg/dl and CRP from 6.2 +/- 1.9 to 3.9 +/- 2.4 mg/l (P < 0.05 for all). This pilot study suggests that the co-administration of E and A at 10 mg/day in renal transplant patients receiving CsA is well-tolerated and effective in reducing important cardiovascular risk factors.

Hypolipidemic therapy for the metabolic syndrome

The metabolic syndrome appears to affect a significant proportion of the population and is associated with increased risk for development of cardiovascular disease as well as of type-2 diabetes. No single treatment for the metabolic syndrome as a whole yet exists. While the primary management of patients with the metabolic syndrome involves healthy lifestyle promotion, the atherogenic dyslipidemia is a primary target for cardiovascular disease risk reduction in these patients. Statin therapy provides effective reduction of LDL-cholesterol, which represents the primary therapeutic goal of lipid-lowering therapy in patients at risk for cardiovascular disease. Fibrates in turn are effective in normalizing lipid levels (mainly triglycerides and HDL-cholesterol) in patients with the metabolic syndrome and may improve insulin resistance. Whereas statins remain the drug of choice for patients who need to achieve the LDL-cholesterol goal, fibrate therapy may represent an alternative for those with low HDL-cholesterol and high triglyceride levels. The simultaneous use of fibrates could be indicated in patients whose LDL-cholesterol is controlled by statin therapy but whose HDL-cholesterol and/or triglycerides are still inappropriate. Such a combination, however, needs careful monitoring due to the potential hazard of adverse drug interactions. Nicotinic acid and ezetimibe may be useful agents for therapy, particularly when combined with statins. A number of emerging therapies offer potential as future options for the pharmacological treatment of metabolic syndrome.

Pharmacokinetic and pharmacodynamic alterations of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors: drug-drug interactions and interindividual differences in transporter and metabolic enzyme functions

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used for the treatment of hypercholesterolemia. Their efficacy in preventing cardiovascular events has been shown by a large number of clinical trials. However, myotoxic side effects, sometimes severe, including myopathy or rhabdomyolysis, are associated with the use of statins. In some cases, such toxicity is associated with pharmacokinetic alterations. In this review, the pharmacokinetic aspects and physicochemical properties of statins are reviewed in order to understand the mechanism governing their pharmacokinetic alterations. Among the statins, simvastatin, lovastatin and atorvastatin are metabolized by cytochrome P450 3A4 (CYP3A4) while fluvastatin is metabolized by CYP2C9. Cerivastatin is subjected to 2 metabolic pathways mediated by CYP2C8 and 3A4. Pravastatin, rosuvastatin and pitavastatin undergo little metabolism. Their plasma clearances are governed by the transporters involved in the hepatic uptake and biliary excretion. Also for other statins, which are orally administered as open acid forms (i.e. fluvastatin, cerivastatin and atorvastatin), hepatic uptake transporter(s) play important roles in their clearances. Based on such information, pharmacokinetic alterations of statins can be predicted following coadministration of other drugs or in patients with lowered activities in drug metabolism and/or transport. We also present a quantitative analysis of the effect of some factors on the pharmacokinetics of statins based on a physiologically based pharmacokinetic model. To avoid a pharmacokinetic alteration, we need to have information about the metabolizing enzyme(s) and transporter(s) involved in the pharmacokinetics of statins and, along with such information, model-based prediction is also useful.

Effect of Atorvastatin Treatment on Isoproterenol-Induced Myocardial Infarction in Rats

In the present study, chronic treatment of atorvastatin was evaluated on isoproterenol-induced myocardial infarction. Male Sprague-Dawley rats (200 +/- 25 g) were randomized into the following four groups: (1) control group, (2) isoproterenol-treated group, (3) atorvastatin-treated group, and (4) isoproterenol- and atorvastatin-treated group. Various serum and tissue parameters as well as histopathological studies were carried out in all groups. Isoproterenol administration produced severe myocardial damage and oxidative stress in rats. Atorvastatin treatment reduced myocardial infarction which has been reflected by improvement in serum parameters, ATPase activities and histopathological lesions. However, it could not reduce oxidative stress and hypertrophy induced by isoproterenol. Hence, it can be concluded that atorvastatin may protect myocardial infarction induced by isoproterenol independent of its antioxidant properties.

Simvastatin improves biochemical parameters in women with polycystic ovary syndrome: results of a prospective, randomized trial

OBJECTIVE

To test the hypothesis that statins improve hyperandrogenemia in women with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, randomized trial.

SETTING

Academic medical center.

PATIENT(S)

Forty-eight women with PCOS.

INTERVENTION(S)

Subjects were randomized to a statin group (simvastatin, 20 mg daily plus oral contraceptive pill [OCP]; n = 24) or an OCP group (OCP alone; n = 24).

MAIN OUTCOME MEASURE(S)

Serum T.

RESULT(S)

Baseline parameters of both groups were comparable. After 12 weeks of treatment, serum T levels declined by 41% in the statin group and by 14% in the OCP group. In the statin group, there was a greater decrease of LH (43% decrease vs. 9% in the OCP group) and a greater decline of LH/FSH ratio (44% vs. 12%). In the statin group, total cholesterol declined by 10% and low-density lipoprotein (LDL) by 24%. In the OCP group, total cholesterol increased by 8%, and LDL was unchanged.

CONCLUSION(S)

This is the first study demonstrating that statin decreases T levels and normalizes gonadotropin levels in women with PCOS. Statin therapy might offer a novel approach, providing endocrine and cardiovascular benefits.

Statins and osteoporosis: new role for old drugs

Osteoporosis is the most common bone disease, affecting millions of people worldwide and leading to significant morbidity and high expenditure. Most of the current therapies available for its treatment are limited to the prevention or slowing down of bone loss rather than enhancing bone formation. Recent discovery of statins (HMG-CoA reductase inhibitors) as bone anabolic agents has spurred a great deal of interest among both basic and clinical bone researchers. In-vitro and some animal studies suggest that statins increase the bone mass by enhancing bone morphogenetic protein-2 (BMP-2)-mediated osteoblast expression. Although a limited number of case-control studies suggest that statins may have the potential to reduce the risk of fractures by increasing bone formation, other studies have failed to show a benefit in fracture reduction. Randomized, controlled clinical trials are needed to resolve this conflict. One possible reason for the discrepancy in the results of preclinical, as well as clinical, studies is the liver-specific nature of statins. Considering their high liver specificity and low oral bioavailability, distribution of statins to the bone microenvironment in optimum concentration is questionable. To unravel their exact mechanism and confirm beneficial action on bone, statins should reach the bone microenvironment in optimum concentration. Dose optimization and use of novel controlled drug delivery systems may help in increasing the bioavailability and distribution of statins to the bone microenvironment. Discovery of bone-specific statins or their bone-targeted delivery offers great potential in the treatment of osteoporosis. In this review, we have summarized various preclinical and clinical studies of statins and their action on bone. We have also discussed the possible mechanism of action of statins on bone. Finally, the role of drug delivery systems in confirming and assessing the actual potential of statins as anti-osteoporotic agents is highlighted.

Modulatory Effects of Atorvastatin on Endothelial Cell–Derived Chemokines, Cytokines, and Angiogenic Factors

STUDY OBJECTIVE

To investigate the immunomodulatory effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) by determining whether atorvastatin alters the production of specific endothelium-derived immunoactive proteins and whether its treatment effects depend on its concentration and/or inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase.

DESIGN

In vitro study using a multiplexing method for protein measurement.

SETTING

University laboratory.

MEASUREMENTS AND MAIN RESULTS

Human umbilical vein endothelial cells were cultured to approximately 80% confluence and treated with atorvastatin 1-50 microM alone or with mevalonate for 24 hours. Untreated cells served as controls. Culture-conditioned media were removed and multiplex assayed for protein content of epithelial neutrophil-activating peptide-78, interleukin-8, monocyte chemotactic protein-1, interleukin-6, interleukin-10, fibroblast growth factor, and granulocyte colony stimulating factor. Atorvastatin significantly reduced the production of epithelial neutrophil-activating peptide-78, interleukin-6, interleukin-8, and monocyte chemotactic protein-1 (p<0.001 to p<0.05) in a concentration-dependent manner without affecting basal production of interleukin-10, fibroblast growth factor, and granulocyte colony stimulating factor. The treatment effects of atorvastatin were reversed with concurrent mevalonate therapy.

CONCLUSION

By inhibiting 3-hydroxy-3-methylglutaryl coenzyme A reductase, atorvastatin lowered concentrations of several inflammatory molecules derived from basal-state endothelial cells in a concentration-dependent manner. The in vivo importance of these immunomodulatory effects needs further investigation.

Statins and bone metabolism

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are potent inhibitors of cholesterol biosynthesis. Cholesterol-lowering therapy using statins significantly reduces the risk of coronary heart disease. However, extensive use of statins leads to increases of other undesirable as well as beneficial effects, so-called pleiotropic effects. With respect to these effects, statins augment the expression of bone morphogenetic protein-2, a potent simulator of osteoblast differentiation and its activity, and promote mineralization by cultured osteoblasts, indicating that statins have an anabolic effect on bone. Chronic administration of statins in ovariectomized (OVX) rats modestly increases bone mineral density (BMD) of cancellous bone but not of compact bone. In clinical studies, there are conflicting results regarding the clinical benefits of this therapy for the treatment of osteoporosis. Observational studies suggest an association between statin use and reduction in fracture risk. Clinical trials reported no effect of statin treatment on BMD in hip and spine, and on bone turnover. Statins also may influence oral osseous tissues. Administration of statins in combination with osteoporosis therapy appears to improve alveolar bone architecture in the mandibles of OVX rats with maxillary molar extraction. Statins continue to be considered as potential therapeutic agents for patients with osteoporosis and possibly with periodontal disease. Development of new statins that are more specific and potent for bone metabolism will greatly increase the usefulness of these drugs for the treatment of bone diseases.

Pharmacogenomics of cholesterol-lowering therapy

The prevention of cardiovascular disease is critically dependent on lipid-lowering therapy, including 3-hydroxymethyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins), cholesterol absorption inhibitors, bile acid resins, fibrates, and nicotinic acid. Although these drugs are generally well tolerated, severe adverse effects can occur in a minority of patients. Furthermore, a subset of patients does not respond to cholesterol-lowering therapy with a reduction in coronary heart disease progression. Significant progress has been made in the identification of common DNA sequence variations in genes influencing the pharmacokinetics and pharmacodynamics of statins and in disease-modifying genes relevant for coronary heart disease (CHD). Among the most promising candidate genes for pharmacogenomic analysis of statin therapy are HMG-CoA reductase as a direct target gene and other genes modulating lipid and lipoprotein homeostasis. Based on data from pharmacogenetic trials, a combined analysis of multiple genetic variants in several genes is more likely to give significant results than single gene studies in small cohorts. In the future, pharmacogenomic testing may allow risk stratification of patients to avoid serious side effects and enable clinicians to select lipid-lowering drugs with the highest efficacy resulting in the best response to therapy.

Pitavastatin effect on ATP binding cassette A1-mediated lipid efflux from macrophages: evidence for liver X receptor (LXR)-dependent and LXR-independent mechanisms of activation by cAMP

The promotion of lipid efflux from macrophages is an important ATP binding cassette A1 (ABCA1)-mediated antiatherosclerotic mechanism that prevents peripheral tissues from foam cell accumulation. Statins exert beneficial antiatherosclerotic effects on cardiovascular disease correlated to the cholesterol-lowering properties and the pleiotropic activities. In this work, we investigated the ability of statins to modulate ABCA1-mediated lipid efflux from macrophages, where the protein expression was differently induced. Pitavastatin (0.1-10 microM) and compactin (10 microM) reduced both cholesterol and phospholipid efflux up to 60% from macrophages expressing ABCA1 upon treatment with 8-(4-chlorophenylthio)-cyclic AMP (cpt-cAMP), and this was secondary to a reduction of ABCA1 mRNA and protein content. Conversely, statins did not affect ABCA1 activity when the protein was up-regulated by 22-hydroxycholesterol/9-cis-retinoic acid or through cholesterol loading. Statin inhibition of lipid efflux induced by cpt-cAMP was reversed in the presence of mevalonate, 22-hydroxycholesterol, and cholesterol but not geranyl geraniol. In macrophages obtained from liver X receptor (LXR)-deficient mice, cpt-cAMP still promoted cholesterol efflux, but pitavastatin did not exert any effect. The present work shows that statins may inhibit ABCA1-mediated lipid efflux in macrophages only when ABCA1 protein expression is induced by cpt-cAMP and provides evidence that cAMP may activate ABCA1 independently of an increase of intracellular sterol synthesis but through at least two pathways: one independent of LXR and one involving an intracellular sterol(s) acting as LXR ligand(s). In addition, the lack of inhibitory effect on lipid efflux in cholesterol-loaded macrophages is likely to exclude a potential negative pleiotropic effect by statins.

Muscle Symptoms Associated with Statins: A Series of Twenty Patients

The aim of this study was to examine the clinical profile of statin-induced myalgia in patients with no apparent predisposing factors. Patients who reported muscle complaints that limited daily functioning during statin use were prospectively identified among the patients of Kuusankoski District Hospital and its catchment area, a population of about 100,000, between January 2003 and July 2004. Twenty patients in whom the muscle complaints were probably attributable to the use of a statin were included in this series. There were no cases of severe myopathy or rhabdomyolysis, and the highest creatine kinase value observed was only about 1900 U/l. Of the 18 patients that were evaluable for creatine kinase level, 5 (28%) did not exhibit elevation of creatine kinase and 6 (33%) showed a minor increase only. Following discontinuation of the statin, resolution of symptoms and normalisation of creatine kinase occurred in 11 of the 13 patients with elevated creatine kinase value as well as muscle complaints. Statins may cause clinically important muscle symptoms without inducing a marked creatine kinase elevation.

An automated blood sampling system to measure lovastatin level in plasma and faeces

The aim of this study was to develop an automated sampling method to measure lovastatin in a conscious and freely moving rat. The blood samples were collected by means of the automated blood sampling system DR-II and the faecal samples were collected using a metabolic cage. The concentration of lovastatin was determined by a reversed-phase liquid chromatographic system with a UV absorbance detector. The mobile phase contained acetonitrile and 10 mm NaH2PO4 in the proportions 60:40 (v/v) with a flow-rate of 1 mL/min. The calibration curve was linear in concentration ranges of 0.05-100 and 0.1-100 microg/mL for lovastatin in blood and faecal samples, respectively. Following pharmacokinetic analysis, we identified that the maximum plasma concentration was around 1.18 +/- 0.08 microg/mL at concentration peak time 120 min and almost 78% of loading dose was accumulated in the faeces within 48 h after lovastatin administration (500 mg/kg, p.o.).

Pretreatment with Simvastatin Reduces Lung Injury Related to Intestinal Ischemia-Reperfusion in Rats

In this rat model study we evaluated whether pretreatment with simvastatin affects the severity of acute lung injury caused by intestinal ischemia-reperfusion (I/R). Twenty-four animals were randomly allocated to three equal groups (sham, control, simvastatin). The simvastatin group was pretreated with simvastatin 10 mg x kg(-1) x day(-1) for 3 days, whereas the other groups received placebo. The simvastatin and control groups underwent 60 min of superior mesenteric artery occlusion and 90 min of reperfusion. Compared with the simvastatin group, the control group exhibited significantly more severe intestinal I/R-induced acute lung injury, as indicated by lower Pao2 and oxygen saturation (P = 0.01 and P = 0.005, respectively) and higher mean values for neutrophil infiltration of the lungs (P = 0.003), total lung histopathologic injury score (P = 0.003), lung wet-to-dry weight ratio (P = 0.009), and lung-tissue malondialdehyde levels (P = 0.016). The control and simvastatin groups had similar serum levels and similar bronchoalveolar lavage fluid levels of cytokines (interleukin-1, interleukin-6, and tumor necrosis factor-alpha) and P-selectin at all measurements, except for a significantly higher level of bronchoalveolar lavage fluid P-selectin in the control group (P = 0.006). Pretreatment with simvastatin reduces the severity of acute lung injury induced by intestinal I/R in rats.

Increase in the transcriptional activity of the endothelial nitric oxide synthase gene with fluvastatin: a relation with the -786T>C polymorphism

HMG-CoA reductase inhibitors (statins) increase endothelial nitric oxide (NO) production, although the precise mechanism of this statin induced increase in NO production remains to be elucidated. We examined endothelial nitric oxide synthase (eNOS) mRNA levels, mRNA stability and the transcriptional activities of the eNOS gene in human umbilical vein endothelial cells treated with fluvastatin and simvastatin. We further examined whether the effects of these statins differ dependent upon the -786T>C polymorphism in the eNOS gene, and whether these statins affect gene expression of replication protein A1 (RPA1), which is known to reduce the transcriptional activity of the eNOS gene with the -786C allele. Utilizing the real-time reverse transcription-polymerase chain reaction, fluvastatin significantly increased eNOS mRNA levels and mRNA stability, and decreased RPA1 mRNA levels. Luciferase reporter gene assays revealed that fluvastatin significantly increased the transcriptional activity of the eNOS gene. The effect of fluvastatin was stronger in the -786C/C genotype than in the -786T/T genotype. Simvastatin increased eNOS mRNA levels and mRNA stability, but did not affect the transcriptional activity of the eNOS gene. Fluvastatin increased eNOS mRNA levels by enhancing both the transcriptional activity and mRNA stability. The effect of fluvastatin on the transcriptional activity was augmented in the -786C/C genotype, probably because of a decrease in RPA1 gene expression. Simvastatin increased eNOS mRNA levels only by enhancing mRNA stability. The present study suggests that fluvastatin increases endothelial NO activity and thus may be more beneficial to patients with the -786C allele.

Considerations in the treatment of dyslipidemia associated with chronic kidney failure and renal transplantation

In comparison to the general population, individuals with chronic kidney failure experience an increased risk for atherosclerotic cardiovascular disease attributed predominantly to pronounced abnormalities in lipid metabolism. The emerging consensus is that patients with chronic kidney failure should be treated aggressively for dyslipidemia. Statins reduce the risk of cardiovascular disease in a range of at-risk patients; this class of lipid-lowering drugs should be considered first-line treatment of dyslipidemia observed in renal disease patients. Although the statins share a common lipid-lowering effect, there are differences within this class of drugs. The statins differ in their pharmacokinetic effects, drug interaction profiles, and risk of myotoxicity. This article characterizes the dyslipidemia observed in the renal failure setting and reviews the therapeutic considerations involved in selecting among the statins. Lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, and rosuvastatin are the available statins in the United States.

Clinical implications for statin pleiotropy

PURPOSE OF REVIEW

Atherosclerosis is a multi-factorial condition involving dyslipidemia that can result in cardiovascular disease. Statins are potent inhibitors of cholesterol biosynthesis, and in clinical trials, statins have been shown to be beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to occur much earlier and to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering.

SUMMARY OF FINDINGS

Recent studies indicate that some of the cholesterol-independent or 'pleiotropic' effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent upon isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

SUMMARY

The potential clinical implications of statin pleiotropy suggests that perhaps other biomarkers, in addition to lipid levels, should be used to gauge the full efficacy of statin therapy in patients with cardiovascular risks or that statin therapy may be effective in disease states, such as inflammatory conditions, ischemic stroke or cancer, where elevated cholesterol levels have not been shown to be a strong epidemiological risk for these diseases.

Hydrophilic statin suppresses vein graft intimal hyperplasia via endothelial cell-tropic Rho-kinase inhibition

BACKGROUND

Recent studies suggest that statins can protect the vasculature in a manner that is independent of their lipid-lowering activity through inhibition of the small guanosine triphosphate-binding protein, Rho, and Rho-associated kinase. Little information is available on the inhibitory effect of statins on vein graft intimal hyperplasia, the main cause of late graft failure after bypass grafting. We therefore examined the effects of a hydrophilic statin on vein graft intimal hyperplasia in vivo and Rho-kinase activity in vitro.

METHODS

In the first experiment, rabbits were randomized to a control group (n = 7) that was fed regular rabbit chow or to a pravastatin group (n = 7) that was fed regular rabbit chow supplemented with 10 mg/kg pravastatin sodium. The branches of the jugular vein were ligated and an approximately 3-cm segment of the jugular vein was taken for an autologous reversed-vein graft. The carotid artery was cut and replaced with the harvested autologous jugular vein. At 2 and 4 weeks after the operation, vein grafts in both groups were harvested, and intimal hyperplasia of the vein grafts was assessed. In the second experiment, human umbilical vein endothelial cells and vascular smooth muscle cells were cultured and then treated with 1 micromol/L and 30 micromol/L pravastatin for 24 hours and harvested. Immunoblotting was performed on the resulting precipitates. Quantitative evaluation of phosphorylated myosin binding subunit and endothelial nitric oxide synthase was performed by densitometric analysis.

RESULTS

We demonstrated that oral administration of the hydrophilic statin pravastatin to normocholesterolemic rabbits inhibited intimal hyperplasia of carotid interposition-reversed jugular vein grafts 4 weeks after implantation (pravastatin group, 39.5 +/- 3.5 microm vs control group, 64.0 +/- 7.1 microm; n = 7; P < .05) and suppressed cell proliferation and apoptosis in the neointima 2 weeks after implantation. In addition, we found that pravastatin inhibited Rho-kinase activity and accelerated endothelial nitric oxide synthase expression in human umbilical vein endothelial cells but did not inhibit Rho-kinase activity in vascular smooth muscle cells.

CONCLUSIONS

These novel findings clearly demonstrate that a hydrophilic statin can suppress intimal hyperplasia of the vein graft in vivo and also show endothelial cell-tropic inhibition of Rho-kinase in vitro. Furthermore, these results strongly support the clinical use of hydrophilic statins to prevent intimal hyperplasia of the vein graft after bypass grafting.

CLINICAL RELEVANCE

Late graft failure caused by neointimal hyperplasia limits the efficacy of vein grafting. Various treatments were examined to reduce neointimal hyperplasia, but a standard clinical treatment has not yet been established. We report here the inhibitory effect of pravastatin on the development of vein graft intimal hyperplasia. In addition, we demonstrate that pravastatin showed endothelial cell-tropic benefits through both the inhibition of Rho-kinase activity and acceleration of eNOS expression in vitro. Because the clinical benefits and safety of pravastatin have been established to a certain extent through long-term clinical usage, pravastatin may soon become standard treatment after vein bypass grafting.

Human low-density lipoprotein receptor gene and its regulation

The low-density lipoprotein (LDL) receptor is a transmembrane glycoprotein that mediates the binding and endocytosis of lipoproteins containing apolipoprotein B and E, especially the cholesterol-rich LDL. Mutations in the LDL receptor gene can produce dysfunctional LDL receptors and cause familial hypercholesterolemia. The expression of the LDL receptor gene is under an intriguing regulation by sterol and nonsterol mediators either at the transcriptional level or at the posttranscriptional level, both of which are linked to cell signaling pathways. Upregulation of liver LDL receptor expression is effective in treating hypercholesterolemia. In this review, we focus on the latest progress on the mechanisms and regulation of the LDL receptor gene expression.

Pharmacokinetic interactions between statins and fibrates

Concomitant use of a fibrate and a statin may offer a therapeutic advantage to patients with dyslipidemia, especially in patients whose low-density lipoprotein cholesterol is controlled by statins but whose high-density lipoprotein cholesterol or triglycerides, or both, are not within goal. However, concern about drug-drug interactions may preclude optimal use of combination statin-fibrate therapy. This article reviews the pharmacokinetics between statins and fibrates, addressing risks associated with drug-drug interactions and combination therapy.

Lipid-modified proteins as biomarkers for cardiovascular disease: a review

Lipid-modified proteins are classified based on the identity of the attached lipid, a post- or co-translational modification required for their biological function. At least five different lipid modifications of cysteines, glycines and other residues on the COOH- and NH(2)-terminal domains have been described. Cysteine residues may be modified by the addition of a 16-carbon saturated fatty acyl group by a labile thioester bond (palmitoylation) or by prenylation processes that catalyze the formation of thioether bond with mevalonate derived isoprenoids, farnesol and geranylgeraniol. The NH(2)-terminal glycine residues may undergo a quite distinct process involving the formation of an amide bond with a 14-carbon saturated acyl group (myristoylation), while glycine residues in the COOH-terminal may be covalently attached with a cholesterol moiety by an ester bond. Finally, cell surface proteins can be anchored to the membrane through the addition of glycosylphosphatidylinositol moiety. Several lines of evidence suggest that lipid-modified proteins are directly involved in different steps of the development of lesions of atherosclerosis, from leukocyte recruitment to plaque rupture, and their expression or lipid modification are likely altered during atherogenesis. This review will briefly summarize the different enzymatic pathways of lipid modification and propose a series of lipid-modified proteins that can be used as biomarkers for cardiovascular disease.

The Effect of Six Different Statins on the Proliferation, Migration, and Invasion of Human Smooth Muscle Cells

Intimal hyperplasia (IH) can occur after any vascular injury and results from smooth muscle cells (SMC) proliferation, migration, and invasion into the subintimal space. The purpose of this study was to investigate the effect of six different statins on the proliferation, migration, and invasion of human venous SMC. The statins were all used at their Cmax concentrations. SMCs were used to construct growth curves in the presence of 10% fetal calf serum or 10% fetal calf serum supplemented with the six statins. Migration and invasion experiments were performed using modified Boyden chambers. The invasion experiments were performed using Matrigel coated plates. We found that all of the statins significantly inhibited SMC proliferation compared to the platelet-derived growth factor control (ranging from fluvastatin 33% of control to pravastatin 72% of control, P = 0.03). SMC migration through uncoated polycarbonate membranes in presence of the six statins was significantly reduced (ranging from lovastatin 43% to pravastatin 57% of control, P = 0.006). All six statins also significantly reduced SMC invasion (ranging from fluvastatin 65% to simvastatin 87% of control, P = 0.002). We conclude that the inhibitory effect of statins on SMC proliferation, migration, and invasion is a class, rather than drug specific effect.

Fluvastatin in the treatment of dyslipidemia associated with chronic kidney failure and renal transplantation

Premature atherosclerotic coronary heart disease driven by multiple risk factors is a major cause of morbidity and mortality among the 6 million patients in the United States with chronic renal failure. Consensus is that kidney failure and renal transplantation patients should be treated aggressively for dyslipidemia. Major medical literature databases were searched for published information about fluvastatin, a HMG-CoA reductase inhibitor, used in patients with impaired renal function. This article characterizes the dyslipidemia observed in these clinical settings and reviews the clinical experience with fluvastatin.

Intermolecular differences of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors contribute to distinct pharmacologic and pleiotropic actions

Statin drugs inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and share the common mechanism of lowering circulating levels of low-density lipoprotein (LDL) cholesterol, a powerful indicator of risk for cardiovascular disease. Large clinical trials have documented the benefit of hypolipidemic therapy for both primary and secondary prevention of coronary artery disease and stroke. Recent clinical findings, including direct comparator studies, now indicate that certain statins may slow progression of disease at a rate and to an extent that cannot be solely attributed to LDL reduction. The proposed mechanisms for such pleiotropic actions include enhancement of endothelial-dependent nitric oxide bioavailability, anti-inflammatory activity, and inhibition of oxidative stress. To understand the biochemical basis for such differences among statins, this article reviews their physicochemical properties and pharmacology at the molecular level.

Different time course for prevention of coronary and stroke events by atorvastatin in the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid-Lowering Arm (ASCOT-LLA)

The lipid-lowering properties of statins reduce rates of coronary artery disease (CAD) events and strokes. Findings of recently conducted, longitudinal intervention studies suggest that these benefits occur early and may be, in part, independent of the lipid-lowering properties of statin therapy. We analyzed data from the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid-Lowering Arm (ASCOT-LLA) to determine the timing of cardiovascular risk reduction. Relative risk reductions in CAD events were large compared with placebo, becoming apparent at 30 days and significant within 3 months, but they tended to decrease with time. Risk reductions in stroke were also apparent at 30 days but remained constant throughout the trial. Significant differences in hazard ratio between atorvastatin and placebo occurred at 2-year follow-up. Such apparently differential effects on CAD and stroke events suggest that mechanisms of action for CAD and stroke prevention may be different. These observations support the hypothesis that non-lipid-lowering actions of atorvastatin may have contributed to early protection against CAD in ASCOT-LLA.

Effects of statins on 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibition beyond low-density lipoprotein cholesterol

Statins are potent inhibitors of cholesterol biosynthesis and exert beneficial effects in the primary and secondary prevention of coronary artery disease. However, the overall benefits observed with statins appear to occur much earlier and to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or "pleiotropic" effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of the small guanosine triphosphate-binding proteins Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

Iatrogenic Rheumatic Syndromes in the Elderly

Rheumatic complaints are common in the geriatric population. However, uncommonly autoimmune or musculoskeletal complaints and disorders may arise as a consequence of pharmacotherapy. These rare events include statin myopathy, drug-induced lupus, arthralgias, vasculitis, or tight skin syndromes. This article will discuss the possible iatrogenic causes of rheumatic conditions, potential inciting agents, and the various types of rheumatic manifestations seen in the elderly.

Statin-macrolide interaction risk: a population-based study throughout a general practice database

INTRODUCTION

The myopathy risk associated with statin use increases in case of concomitant prescription of certain drugs, such as cytochrome P(450) (CYP) system inhibitors (i.e., macrolides). The aim of this study was to assess whether concurrent statin/macrolide prescriptions at high interaction risk are commonly written in a general practice setting.

METHODS

For this study, 156 general practitioners (GPs) with a patient population of almost 200,000 individuals, and participating in the Arianna database set up by "Caserta-1" Local health-Service Agency (ASL), were recruited. Within such a study sample, subjects receiving at least one statin/macrolide concomitant prescription during the year 2003 were identified. Sensitivity analysis was performed to assess the time distribution of high-risk macrolide prescriptions written within +/-10 days from the statin prescription date.

RESULTS

Among 190,124 patients included in the study, 7,176 (3.8%) received at least one statin prescription during the observation period. Of these, 228 (3.2%) were occasionally co-prescribed with any macrolide on the same date, in 153 cases (2.1% of statin users) the macrolide being of high interaction risk. In particular, 2.1% (55) of simvastatin users and 2.2% (64) of patients on atorvastatin were prescribed with high-risk macrolide on the same date versus 0.6% and 1.8% of patients prescribed with fluvastatin and pravastatin, respectively. Concerning GPs, 99 (63.5%) co-administered statin and macrolide at high interaction risk at least once.

CONCLUSIONS

Most GPs occasionally prescribed statin/macrolide at high interaction risk on the same date, despite the availability of therapeutic alternatives. Prevention strategies targeted to increase awareness of health professionals about the interaction risks of widely prescribed drugs are needed.

Suboptimal choices and dosing of statins at start of therapy

AIM

To assess dosing and determinants of the choice of statins among starters of statins.

METHODS

Data were obtained from the PHARMO database comprising pharmacy and linked hospital discharge records of approximately 300 000 subjects in the Netherlands. All new users of statins in 1998 were selected. Patient characteristics and drug regimens were compared between starters of different statins. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using polytomous logistic regression modelling, using the start of simvastatin therapy as reference category.

RESULTS

In 1998, 1738 patients started using simvastatin (41.1%), pravastatin (23.1%), fluvastatin (11.9%), atorvastatin (22.8%) or cerivastatin (1.0%). Compared with starters with simvastatin [mean dose 1.02 +/- 0.39 defined daily doses (DDDs)], starters with pravastatin (1.27 +/- 0.56 DDDs) and atorvastatin (1.43 +/- 0.59 DDDs) received higher doses (P < 0.001), whereas users of fluvastatin (0.78 +/- 0.37 DDDs) and cerivastatin (0.81 +/- 0.30 DDDs) received lower doses (P < 0.001). Patients already using CYP3A4 inhibitors more frequently received fluvastatin (OR = 1.80; 95% CI 1.11, 2.94), metabolized by non-CYP3A4 pathways, and atorvastatin (OR = 1.62; 95% CI 1.06, 2.47), which is metabolized by CYP3A4, than simvastatin. Statin doses were not adjusted when prescribed to patients using CYP3A4 inhibitors.

CONCLUSIONS

Many patients starting statin therapy did not receive a statin of first choice. The coadministration of potentially interacting drugs may have led to a change in statin choice, but not in dosage lowering. These findings suggest that the quality of statin therapy could be improved.

Acute Myopathy in a Patient with Concomitant Use of Pravastatin and Colchicine

OBJECTIVE

To report a case of acute myopathy after concomitant use of colchicine and pravastatin.

CASE SUMMARY

A 65-year-old woman was admitted to the hospital with an acute episode of gout. She had been taking pravastatin 20 mg once daily for 6 years. On admission, blood urea nitrogen and serum creatinine levels were 48 mg/dL and 1.3 mg/dL, respectively. Colchicine 1.5 mg/day was added to the treatment regimen, but 20 days after the initiation of colchicine therapy, symmetrical proximal muscle weakness developed in the woman's legs. Physical examination, laboratory findings, and electromyelogram findings suggested myopathy. The Naranjo probability scale indicated a probable relationship between myopathy and combined therapy. Seven days after discontinuation of colchicine and pravastatin, the patient's weakness improved and enzyme levels returned to normal. Colchicine was restarted at 1.0 mg/day 5 days later; no myopathy occurred.

DISCUSSION

Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) and colchicine are known to cause myopathy. Most of the statins and colchicine are biotransformed in the liver primarily by the CYP3A4 system, which may increase the risk of myopathy when concurrent therapy is used. However, pravastatin is not primarily metabolized by cytochrome P450 isoenzymes. The cause of myopathy in our patient may be related to the interaction of colchicine and pravastatin via P-glycoprotein. In addition, the presence of mild renal dysfunction could have contributed to the development of myopathy.

CONCLUSIONS

We suggest that clinicians be aware that neuromuscular toxicity can occur in patients with mild renal dysfunction with combined use of colchicine and pravastatin.

Chemical, pharmacokinetic and pharmacodynamic properties of statins: an update

Statins are the treatment of choice for the management of hypercholesterolaemia because of their proven efficacy and safety profile. They also have an increasing role in managing cardiovascular risk in patients with relatively normal levels of plasma cholesterol. Although all statins share a common mechanism of action, they differ in terms of their chemical structures, pharmacokinetic profiles, and lipid-modifying efficacy. The chemical structures of statins govern their water solubility, which in turn influences their absorption, distribution, metabolism and excretion. Lovastatin, pravastatin and simvastatin are derived from fungal metabolites and have elimination half-lives of 1-3 h. Atorvastatin, cerivastatin (withdrawn from clinical use in 2001), fluvastatin, pitavastatin and rosuvastatin are fully synthetic compounds, with elimination half-lives ranging from 1 h for fluvastatin to 19 h for rosuvastatin. Atorvastatin, simvastatin, lovastatin, fluvastatin, cerivastatin and pitavastatin are relatively lipophilic compounds. Lipophilic statins are more susceptible to metabolism by the cytochrome P(450) system, except for pitavastatin, which undergoes limited metabolism via this pathway. Pravastatin and rosuvastatin are relatively hydrophilic and not significantly metabolized by cytochrome P(450) enzymes. All statins are selective for effect in the liver, largely because of efficient first-pass uptake; passive diffusion through hepatocyte cell membranes is primarily responsible for hepatic uptake of lipophilic statins, while hydrophilic agents are taken up by active carrier-mediated processes. Pravastatin and rosuvastatin show greater hepatoselectivity than lipophilic agents, as well as a reduced potential for uptake by peripheral cells. The bioavailability of the statins differs greatly, from 5% for lovastatin and simvastatin to 60% or greater for cerivastatin and pitavastatin. Clinical studies have demonstrated rosuvastatin to be the most effective for reducing low-density lipoprotein cholesterol, followed by atorvastatin, simvastatin and pravastatin. As a class, statins are generally well tolerated and serious adverse events, including muscle toxicity leading to rhabdomyolysis, are rare. Consideration of the differences between the statins helps to provide a rational basis for their use in clinical practice.

Pleiotropic effects of statins

Statins are potent inhibitors of cholesterol biosynthesis. In clinical trials, statins are beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or "pleiotropic" effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Furthermore, statins have beneficial extrahepatic effects on the immune system, CNS, and bone. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

The influence of age and sex on the clearance of cytochrome P450 3A substrates

Cytochrome P450s (CYPs) are an important family of enzymes in the metabolism of many therapeutic agents and endogenous metabolic reactions. The CYP3A subfamily is especially prominent in these metabolic activities. This review article focuses on how the factors of age and sex may influence the in vivo activity of human CYP3A. The functional activity of CYP3A varies based on issues such as interaction with one or more substrates and between individuals and/or localisation. For CYP3A substrates, intrinsic clearance is the component of total clearance that is contributed by the enzymes. Depending on the route of administration and the contribution of hepatic blood flow to overall clearance, sensitivities to changes in CYP3A activities may differ. Additionally, age may influence the hepatic blood flow and, in turn, affect CYP3A activity. A review of the literature regarding age influences on the clearance of CYP3A substrates does suggest that age can affect the clearance of certain CYP3A substrates.CYP3A is responsible for a large number of endogenous metabolic reactions involving steroid hormones, and enzyme activity has been reported to be induced and/or inhibited in the presence of some sex steroids. Based on published studies for most CYP3A substrates, sex does not appear to influence clearance; however, with certain substrates significant sex-related differences are found. In such cases, women primarily have higher clearance than men.