Rhabdomyolysis associated with hydroxymethylglutaryl-coenzyme A reductase inhibitors

Facts and ideas on statins with respect to their lipophilicity: a focus on skeletal muscle cells and bone besides known cardioprotection

Statins are known to block cholesterol synthesis in the liver. They also exhibit non-lipid pleiotropic effects due to the inhibition of protein prenylation, thereby modulating various signaling pathways of cellular homeostasis and integrity. Both lipid control and pleiotropic action of statins are clinically used, mainly for treatment of hypercholesterolemia and primary and secondary prevention of cardiovascular diseases. Because the prescription of statins is increasing and statin therapy is often lifelong, in particular in patients with other risk factors, safety issues being associated with polymorbidity and polypragmasia as well as the persistence with and adherence to statins are specific points of attention of clinicians and clinical pharmacologists. Furthermore, because skeletal myocytes have a cholesterol inhibitory sensitivity greater than hepatocytes, a choice of an appropriate statin based on its lipophilicity and the associated likelihood of its side effects on skeletal muscle cells and bone is warranted in such polymorbid patients. These approaches can effectively modulate the risk: benefit ratio and highlight a need for personalized therapy as much as possible, thereby minimizing risk of discontinuation of therapy and poor compliance.

First Reported Case of Rhabdomyolysis Associated with Concomitant Use of Cyclosporin, Diltiazem, and Simvastatin

Rhabdomyolysis is a syndrome with a wide range of symptoms ranging from asymptomatic raised serum creatinine kinase to life-threatening metabolic disturbances and acute kidney injury. A careful history taking and high clinical suspicion on drug-drug interaction are crucial to identify the etiology of rhabdomyolysis. Here, we present a case of rhabdomyolysis due to a rare drug-to-drug interaction of simvastatin, diltiazem, and cyclosporin in a patient with IgA nephropathy. Early renal replacement therapy was initiated, and the insulting agents were withheld. Despite the metabolic disturbances were corrected, the patient succumbed to possible venous thromboembolism event during the prolonged hospital stay. Therefore, heightened awareness is required in dealing with patients with glomerulonephritis who are frequently prescribed on polypharmacy, in order to reduce unwarranted adverse events.

Cholesterol in myasthenia gravis

The cholinergic neuromuscular junction is the paradigm peripheral synapse between a motor neuron nerve ending and a skeletal muscle fiber. In vertebrates, acetylcholine is released from the presynaptic site and binds to the nicotinic acetylcholine receptor at the postsynaptic membrane. A variety of pathologies among which myasthenia gravis stands out can impact on this rapid and efficient signaling mechanism, including autoimmune diseases affecting the nicotinic receptor or other synaptic proteins. Cholesterol is an essential component of biomembranes and is particularly rich at the postsynaptic membrane, where it interacts with and modulates many properties of the nicotinic receptor. The profound changes inflicted by myasthenia gravis on the postsynaptic membrane necessarily involve cholesterol. This review analyzes some aspects of myasthenia gravis pathophysiology and associated postsynaptic membrane dysfunction, including dysregulation of cholesterol metabolism in the myocyte brought about by antibody-receptor interactions. In addition, given the extensive therapeutic use of statins as the typical cholesterol-lowering drugs, we discuss their effects on skeletal muscle and the possible implications for MG patients under chronic treatment with this type of compound.

Alleviation of Simvastatin-Induced Myopathy in Rats by the Standardized Extract of Ginkgo Biloba (EGb761): Insights into the Mechanisms of Action

Statins are the most widely prescribed cholesterol-lowering drugs to reduce the risk of cardiovascular diseases. Statin-induced myopathy is the major side effect of this class of drugs. Here, we studied whether standardized leaf extracts of ginkgo biloba (EGb761) would improve simvastatin (SIM)-induced muscle changes. Sixty Wistar rats were allotted into six groups: control group, vehicle group receiving 0.5% carboxymethyl cellulose (CMC) for 30 days, SIM group receiving 80 mg/kg/day SIM in 0.5% CMC orally for 30 days, SIM withdrawal group treated with SIM for 16 days and sacrificed 14 days later, and EGb761-100 and EGb761-200 groups posttreated with either 100 or 200 mg/kg/day EGb761 orally. Muscle performance on the rotarod, serum creatine kinase (CK), coenzyme Q10 (CoQ10), serum and muscle nitrite, muscle malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) activities were estimated. Additionally, muscle samples were processed for histopathological evaluation. We found that SIM decreased muscle performance on the rotarod, serum CoQ10, as well as muscle SOD and CAT activities while it increased serum CK, serum and muscle nitrite, as well as muscle MDA levels. SIM also induced sarcoplasmic vacuolation, splitting of myofibers, disorganization of sarcomeres, and disintegration of myofilaments. In contrast, posttreatment with EGb761 increased muscle performance, serum CoQ10, as well as muscle SOD and CAT activities while it reduced serum CK as well as serum and muscle nitrite levels in a dose-dependent manner. Additionally, EGb761 reversed SIM-induced histopathological changes with better results obtained by its higher dose. Interestingly, SIM withdrawal increased muscle performance on the rotarod, reduce serum CK and CoQ10, and reduced serum and muscle nitrite while it reversed SIM-induced histopathological changes. However, SIM withdrawal was not effective enough to restore their normal values. Additionally, SIM withdrawal did not improve SIM-induce muscle MDA, SOD, or CAT activities during the period studied. Our results suggest that EGb761 posttreatment reversed SIM-induces muscle changes possibly through its antioxidant effects, elevation of CoQ10 levels, and antagonizing mitochondrial damage.

Bone union formation in the rat mandibular symphysis using hydroxyapatite with or without simvastatin: effects on healthy, diabetic, and osteoporotic rats

OBJECTIVE

The objective is to compare new bone formation in critical defects in healthy, diabetic, and osteoporotic rats filled with hydroxyapatite (HA) alone and HA combined with simvastatin (SV).

MATERIALS AND METHODS

A total of 48 adult female Sprague-Dawley rats were randomized into three groups (n = 16 per group): Group, 1 healthy; Group 2, diabetics; and Group 3, osteoporotics. Streptozotocin was used to induce type 1 diabetes in Group 2, while bilateral ovariectomy was used to induce osteoporosis in Group 3. The central portion of the rat mandibular symphysis was used as a physiological critical bone defect. In each group, eight defects were filled with HA alone and eight with HA combined with SV. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2).

RESULTS

In all groups (healthy, diabetics, and osteoporotics), the defects filled with HA + SV presented greater radiological bone union, BMD, histological bone union, and more VEGF and BMP-2 positivity, in comparison with bone defects treated with HA alone.

CONCLUSIONS

Combined application of HA and SV improves bone regeneration in mandibular critical bone defects compared with application of HA alone in healthy, diabetic, and osteoporotic rats.

CLINICAL RELEVANCE

This study might help to patients with osteoporosis or uncontrolled diabetes type 1, but future studies should be done.

Comparative and quantitative assessment on statin efficacy and safety: insights into inter-statin and inter-individual variability via dose- and exposure-response relationships

Introduction: Statins are prescribed widely for cholesterol-lowering therapy, but it is known that their efficacy and safety profiles vary, despite the shared pharmacophore and pharmacological target. The immense body of related clinical and preclinical data offers a unique opportunity to explore the possible factors underlying inter-statin and inter-individual variabilities.Area covered: Clinical and preclinical data from various statins were compiled with regard to the efficacy (cholesterol-lowering effect) and safety (muscle toxicity). Based on the compiled data, dose- and exposure-response relationships were explored to obtain mechanistic and quantitative insights into the variations in the efficacy and safety profiles of statins.Expert opinion: Our analyses indicated that the inter-statin variability in the cholesterol-lowering effect may be mainly attributable to variations in potency of inhibition of the pharmacological target, rather than variations in drug exposure at the site of drug action. However, the drug exposure at the sites of drug action (i.e., the liver for efficacy and the muscle for safety) may contribute to the differences in the efficacy and safety observed in individual patients.

Creatine, Creatine Kinase, and Aging

With an ever aging population, identifying interventions that can alleviate age-related functional declines has become increasingly important. Dietary supplements have taken center stage based on various health claims and have become a multi-million dollar business. One such supplement is creatine, a major contributor to normal cellular physiology. Creatine, an energy source that can be endogenously synthesized or obtained through diet and supplement, is involved primarily in cellular metabolism via ATP replenishment. The goal of this chapter is to summarize how creatine and its associated enzyme, creatine kinase, act under normal physiological conditions, and how altered levels of either may lead to detrimental functional outcomes. Furthermore, we will focus on the effect of aging on the creatine system and how supplementation may affect the aging process and perhaps reverse it.

Ticagrelor and Statin Interaction Induces Rhabdomyolysis and Acute Renal Failure: Case reports and Scoping Review

Ever since evidence about the increased risk of stent thrombosis with drug eluting stents (DES) surfaced in 2005, the Food and Drug Administration (FDA) has recommended the use of dual antiplatelet therapy (aspirin with P2Y12 inhibitor) following DES placement. The PLATO trial demonstrated lower mortality rates with the use of Ticagrelor when compared to clopidogrel (9.8% vs. 11.7%, p<0.001) when treating patients with acute coronary syndrome. Given their pleiotropic benefits, statins are today the second most prescribed drug in the United States and often co-prescribed with Ticagrelor. FDA's post market surveillance of Ticagrelor use along with statins in post-myocardial infarction care is now revealing novel and serious adverse events. We present two cases of rhabdomyolysis and acute renal failure (ARF) which develop while the patients were on statins and Ticagrelor. Case 1: A 66-year-old female presented with bilateral thigh pain for 3 days. One month prior to presentation, she was managed for non-ST segment elevation myocardial infarction (NSTEMI) and had been started on aspirin, ticagrelor and simvastatin. Laboratory values revealed creatinine kinase (CK) level at 40,000 U/L and creatinine 3.2 mg/dL suggesting rhabdomyolysis and ARF. Case 2: A 63-year-old male presented with generalized body aches and fatigue for 4 days. He had sustained STEMI two months before and received two drug eluting stents (DES) and aspirin, ticagrelor and rosuvastatin had been initiated. CK was 380,000 U/L and creatinine 7.94 mg/dL suggesting rhabdomyolysis and ARF. Both patients presented with rhabdomyolysis and acute renal failure within weeks after ticagrelor and statin were commenced. A review of the literature indicated that 11 similar cases of ticagrelor-induced ARF and rhabdomyolysis had been reported. Ticagrelor competes with statins when metabolized by cytochrome P450 (CYP) 3A4 leading to statin retention, leading to major adverse effects like rhabdomyolysis and acute renal failure. Our review is intended to alert clinicians about this important drug interaction.

The effect of statin therapy on endoplasmic reticulum stress

The endoplasmic reticulum (ER) is critical in protein processing and particularly in ensuring that proteins undergo their correct folding to exert their functionality. What is becoming increasingly clear is that the ER may undergo increasing stress brought about by nutrient deprivation, hypoxia, oxidized lipids, point mutations in secreted proteins, cellular differentiation or significant deviation from metabolic set points, and loss of Ca²⁺ homeostasis, with detrimental effects on ER-resident calcium-dependent chaperones, alone or in combination. This results in the unfolded protein response (UPR) that is a repair mechanism to limit the formation of newly damaged proteins until ER homeostasis is restored, though may result in increased cell death. ER stress has been shown to be implicated in a variety of diseases. Statins are well-known cholesterol-lowering drugs and have been extensively reported to possess beneficial cholesterol-independent effects in a variety of human diseases. This review focuses on the concept of ER stress, the underlying molecular mechanisms and their relationship to the pathophysiology and, finally, the role of statins in moderating ER stress and UPR.

Rhabdomyolysis in a Patient Treated with Colchicine and Atorvastatin

Objective:

To report a case of severe rhabdomyolysis that developed after administration of atorvastatin to a patient receiving regular colchicine treatment.

Case Summary:

A 45-year-old man with nephrotic syndrome and amyloidosis presented with dyspnea, altered mentation, and severe fatigue. He had been taking colchicine 1.5 mg/day for amyloidosis for 3 years without adverse effects. Atorvastatin 10 mg/day was prescribed for hypercholesterolemia one month prior to admission. After 2 weeks of atorvastatin treatment, he began to experience myalgia and reduced muscle strength. The creatinine and creatine kinase concentrations on admission were 8.1 mg/dL and 9035 U/L, respectively. The patient was diagnosed with rhabdomyolysis with the findings of myoglobinuric, oliguric acute renal failure, and more than 50–fold elevated creatine kinase concentration. His muscle strength improved after withdrawal of atorvastatin and colchicine. However, he died because of nosocomial pneumonia that developed during his hospital stay. The Naranjo probability scale indicated that atorvastatin and colchicine were probable causes of rhabdomyolysis.

Discussion:

Atorvastatin and colchicine have well-known myotoxic adverse effects. Despite atorvastatin's proven safety, its use with certain drugs, such as colchicine, makes it a potential myotoxic drug. This might be because concomitant administration of P-glycoprotein substrates, such as statins, and colchicine, which is a P-glycoprotein inhibitor, modifies pharmacokinetics by increasing bioavailability and organ uptake of the substrates, leading to more adverse reactions and toxicities.

Conclusions:

We recommend checking the creatine kinase level one week after prescribing 2 or more potentially myotoxic drugs concomitantly, after dose increase of a myotoxic drug, or after prescribing a new drug to a patient already using other myotoxic agents.

Hypolipidemic effect of β-caryophyllene to treat hyperlipidemic rats

The aim of this study was to evaluate the effect of β-caryophyllene on hypercholesterolemia using a model of hyperlipidemia induced by Triton WR-1339 in rats, as well as its possible effect on hepatic antioxidant enzymes. Thus, total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol were measured in serum, while reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), hepatic 3-hydroxy-3-methylglutayl coenzyme A (HMG-CoA) reductase, superoxide dismutase (SOD), and catalase (CAT) activities were measured in the hepatic tissue. In addition, seric concentrations of β-caryophyllene were measured to perform correlation studies. Serum samples from hypercholesterolemic rats show higher (p < 0.05) levels of total cholesterol, triglycerides, and LDL cholesterol, and lower (p < 0.05) levels of HDL cholesterol compared to non-hypercholesterolemic rats. β-Caryophyllene treatment reduced (p < 0.05) the levels of total cholesterol, triglycerides and LDL cholesterol, similar to the reference drug simvastatin. However, HDL cholesterol levels did not increase with the treatment. β-Caryophyllene treatment was able to inhibit the HMG-CoA reductase activity, as well as to prevent the increase on ROS and TBARS levels, and ameliorate the antioxidant system. In summary, our findings demonstrated that β-caryophyllene has hypolipidemic effect via inhibition of the hepatic HMG-CoA reductase, like the standard drug simvastatin, and this inhibition suggests a possible mechanism of hypolipidemic action. Thus, our results indicate that β-caryophyllene can be used to treat dyslipidemic diseases because it exerts a similar effect as the reference drug, protecting the liver against lipid damage and improving the hepatic antioxidant defense system.

Myopathy in older people receiving statin therapy: a systematic review and meta-analysis

OBJECTIVE

The aim of the present study was to determine the risk of myopathy in older people receiving statin therapy.

METHODS

Eligible studies were identified searching Ovid Medline, EMBASE, Scopus, CINAHL, Cochrane and PSYCHINFO databases (1987 to July 2014). The selection criteria comprised randomized controlled studies that compared the effects of statin monotherapy and placebo on muscle adverse events in the older adult (65+ years). Data were extracted and assessed for validity by the authors. Odds ratios and 95% confidence intervals (CIs) were used to calculate binary outcomes. Evidence from included studies were pooled in a meta-analysis using Revman 5.3.

RESULTS

The trials assessed in the systematic review showed little or no evidence of a difference in risks between treatment and placebo groups, with myalgia [odds ratio (OR) 1.03, 95% CI 0.90, 1.17; I(2) = 0%; P = 0.66] and combined muscle adverse events (OR 1.03, 95% CI 0.91, 1.18; I(2) = 0%; P = 0.61) (myopathy). No evidence was found for an increased risk of rhabdomyolysis (OR 2.93, 95% CI 0.30, 28.18; I(2) = 0%; P = 0.35) in the seven trials that reported this. No trials reported mortality due to a muscle-related event. Discontinuations due to an adverse effect were reduced in the treatment group compared with placebo (OR 0.74, 95% CI 0.50, 1.09; I(2) = 0%; P = 0.13).

CONCLUSION

The results obtained from the present review suggest that statins are relatively safe, even in older people. There was no evidence to suggest an increased risk of myopathy in older adults receiving statin therapy. There is slightly increased seen with rhabdomyolysis when compared with the general population, although the event is relatively rare. Statins should be prescribed to elderly people who need it, and not withheld, as its myopathy safety profile is tolerable.

Predictors and outcomes of increases in creatine phosphokinase concentrations or rhabdomyolysis risk during statin treatment

AIM

The aim was to evaluate clinical risk factors associated with myotoxicity in statin users.

METHODS

This was a cohort study of patients prescribed a statin in UK primary care practices contributing to the Clinical Practice Research Datalink. Outcomes of interest were creatine phosphokinase (CPK) concentrations and clinical records of rhabdomyolysis.

RESULTS

The cohort comprised 641,703 statin users. Simvastatin was most frequently prescribed (66.3%), followed by atorvastatin (24.4%). CPK was measured in 127,209 patients: 81.4% within normal range and 0.7% above <four times the upper limit of normal (ULN). Rhabdomyolysis was recorded in 59 patients. Patients with concomitant prescribing of CYP3A4-interacting drugs had an increased odds ratio (OR) of rhabdomyolysis compared with controls (OR 3.71, 95% CI 1.18, 11.61) and >four times ULN CPK compared with normal CPK (OR 1.28, 95% CI 1.01, 1.60). Rosuvastatin users had higher risk of >four times ULN CPK (OR 1.62, 95% CI 1.22, 2.15) as did patients with larger daily doses of other statin types. A recent clinical record of myalgia was associated with an increased OR of >four times ULN CPK (OR 1.73, 95% CI 1.37, 2.18). In patients who were rechallenged to statins and had repeat CPK measurements after >four times ULN CPK abnormalities, 54.8% of the repeat CPK values were within normal range, 32.1% between one to three times and 13.0% >four times ULN.

CONCLUSIONS

The frequencies of substantive CPK increases and rhabdomyolysis during statin treatment were low, with highest risks seen in those on large daily doses or interacting drugs and on rosuvastatin. CPK measurements appeared to have been done in a haphazard manner and better guidance is needed.

Are there any benefits from statin treatment for the septic patient?

Statins have become the most widely used drugs for lowering cholesterol levels worldwide. At least 20% of patients requiring admission to hospital are on established statin therapy, and this proportion is growing each year. Evidence from observational studies and basic science research suggests that statins might be associated with a reduced mortality in sepsis. Randomized trials are producing equivocal results but have not shown the marked improvement in outcome suggested by the observational studies. Continued use in current statin users appears a more fruitful area for future research than statin use de novo as an adjuvant therapy in sepsis. Statin use in patients with pneumonia, acute lung injury or early sepsis warrants further study. International practice of statin use in critically ill patients is variable, and potential toxicity mandates careful monitoring. Further studies are required to address fundamental issues such as efficacy, potential target patient populations, dose, class equivalence and safety.

Hypolipidemic action of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice

Chrysin (5,7-dihydroxyflavone) is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts. The objective of this study was to investigate the hypolipidemic properties of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice. Triton WR-1339 was administered intraperitoneally (400 mg/kg) to overnight-fasted mice to develop acute hyperlipidemia. Chrysin was administered orally (10 mg/kg) 30 min before Triton WR-1339. At 24 h after Triton WR-1339 injection, blood samples were collected to measure plasma lipid levels. The hepatic thiobarbituric acid reactive substances (TBARS), carbonyl content, non-protein sulfhydryl (NPSH) and ascorbic acid (AA) levels, as well as catalase (CAT) and superoxide dismutase (SOD) activity were recorded. Chrysin administration significantly decreased total cholesterol levels. In addition, it partially decreased non-high density lipoprotein-cholesterol and triglycerides levels in plasma of hyperlipidaemic mice. In addition chrysin administration prevented the increase on TBARS levels and prevented the decrease in SOD activity induced by Triton WR-1339. These findings indicated that chrysin was able to decrease plasma lipids concentration and that its antioxidant properties was, at least in part, involved in the hypolipidaemic action of chrysin.

Statin-induced rhabdomyolysis: a comprehensive review of case reports

PURPOSE

To identify case reports of statin-induced rhabdomyolysis and summarize common predisposing factors, symptoms, diagnostic findings, functional outcomes, characteristics, treatment, and rehabilitation.

METHOD

MEDLINE, CINAHL, SCOPUS, and PEDro databases were searched (1990-2013) for relevant case reports using the search terms "Statins," "Rhabdomyolysis," "Myalgia," "Muscle damage," "Muscle injury," and "Myopathy." Relevance (based on title and abstract) was assessed by one investigator; two investigators independently reviewed the relevant articles to determine inclusion in the review.

RESULTS

A total of 112 cases met the inclusion criteria. The majority were in men (70%) and people over 45 years of age (mean 64 [SD 14] years). Simvastatin was the most commonly reported statin (n=55); the majority of cases reported the use of concomitant medications such as fibrates (n=25). Weakness (n=65) and muscle pain (n=64) were the most common symptoms. In 19 cases, the patient was referred to rehabilitation, but the case reports do not include descriptions of the treatment.

CONCLUSION

Statin-induced rhabdomyolysis was more commonly reported when statins were used in conjunction with other drugs, which potentiated its effect. Research is needed to identify the role of exercise and rehabilitation following statin-induced rhabdomyoloysis since muscle damage may be severe and may have long-term effects on muscle function.

Statin-associated necrotizing autoimmune myopathy

Necrotizing autoimmune myopathy (NAM) is a severe adverse effect of statins. We report a 66-year-old Caucasian female who had progressive proximal muscle weakness after treatment with statins. Results of a muscle biopsy showed necrotizing myopathy with minimal inflammatory cell infiltrate and increased major histocompatibility class I antigen expression in muscle fibers. The clinical and laboratory parameters improved significantly with immunosuppressive treatment. Although it is a rare event, statin-induced NAM should be included as a differential diagnosis of myopathies.

Statin myotoxicity: a review of genetic susceptibility factors

The 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors (statins) are among the most common medications prescribed worldwide, but their efficacy and toxicity vary between individuals. One of the major factors contributing to intolerance and non-compliance are the muscle side-effects, which range from mild myalgia through to severe life-threatening rhabdomyolysis. One way to address this is pharmacogenomic screening, which aims to individualize therapy to maximize efficacy whilst avoiding toxicity. Genes encoding proteins involved in the metabolism of statins as well as genes known to cause inherited muscle disorders have been investigated. To-date only polymorphisms in the SLCO1B1 gene, which encodes the protein responsible for hepatic uptake of statins, and the COQ2 gene, important in the synthesis of coenzyme Q10, have been validated as being strongly associated with statin-induced myopathy. The aim of this review is to summarize studies investigating genetic factors predisposing to statin myopathy and myalgia, as the first step towards pharmacogenomic screening to identify at risk individuals.

Simvastatin-loaded β-TCP drug delivery system induces bone formation and prevents rhabdomyolysis in OVX mice

Bone formation and regeneration is a prolonged process that requires a slow drug release system to assist in the long-term recovery. A drug-delivery system is developed that allows for the controlled release of simvastin, without exhibiting the side effects associated with high concentrations of simvastatin, and is still capable of inducing constant bone formation.

Effects of simvastatin on osseointegration in a canine total hip arthroplasty model: an experimental study

Simvastatin was recently demonstrated to stimulate bone morphogenetic protein-2 expression, leading to bone formation. The present study was designed to evaluate whether simvastatin administered by injection could promote osseointegration in a canine total hip arthroplasty model. Fifteen dogs were divided into 3 groups of 5 dogs each: group 1 (high-dosage simvastatin, 6.0 mg/[kg d]), group 2 (low-dosage simvastatin, 3.0 mg/[kg d]), and a control group (isotonic saline, 3.0 mg/[kg d]). Osseointegration was assessed by using the push-out test, scanning electron microscopy, energy-dispersive spectrometer microanalysis, and histomorphometric examination. The results showed higher mechanical strength, greater area of bone covering the femoral component, and higher bone-implant contact in group 1 than in the other 2 groups. Our findings indicate that simvastatin administered by injection could contribute significantly to osseointegration in a canine total hip arthroplasty model.

Simvastatin inhibits osteoclast differentiation by scavenging reactive oxygen species

Osteoclasts, together with osteoblasts, control the amount of bone tissue and regulate bone remodeling. Osteoclast differentiation is an important factor related to the pathogenesis of bone-loss related diseases. Reactive oxygen species (ROS) acts as a signal mediator in osteoclast differentiation. Simvastatin, which inhibits 3-hydroxy-3-methylglutaryl coenzyme A, is a hypolipidemic drug which is known to affect bone metabolism and suppresses osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL). In this study, we analyzed whether simvastatin can inhibit RANKL-induced osteoclastogenesis through suppression of the subsequently formed ROS and investigated whether simvastatin can inhibit H2O2-induced signaling pathways in osteoclast differentiation. We found that simvastatin decreased expression of tartrate-resistant acid phosphatase (TRAP), a genetic marker of osteoclast differentiation, and inhibited intracellular ROS generation in RAW 264.7 cell lines. ROS generation activated NF-κB, protein kinases B (AKT), mitogen-activated protein kinases signaling pathways such as c-JUN N-terminal kinases, p38 MAP kinases as well as extracellular signal- regulated kinase. Simvastatin was found to suppress these H2O2-induced signaling pathways in osteoclastogenesis. Together, these results indicate that simvastatin acts as an osteoclastogenesis inhibitor through suppression of ROS-mediated signaling pathways. This indicates that simvastatin has potential usefulness for osteoporosis and pathological bone resorption.

Highly efficient release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles enhances bone repair in rats

Lovastatin exhibits higher thermal stability and lower degradation rate than simvastatin. However, the amount of research studying a lovastatin delivery device has been far less than similar research on simvastatin. As a consequence, a high lovastatin release rate system has not been developed. We hypothesized that highly efficient release of lovastatin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a short-term release (7 days) could provide an effective delivery system for bone repair. This study optimized the emulsion (o/w) technique in the fabrication process for PLGA nanoparticles, thereby producing the first recorded case of a high release rate (97%) of lovastatin. We also calculated the calibration curve of lovastatin using a UV spectrometer. The results demonstrated that the ALPase activity in human osteoblasts could be significantly stimulated by lovastatin carried in PLGA nanoparticles, but was prominently decreased by free lovastatin with the concentration higher than 4 µg/ml. Animal studies showed that the amount of lovastatin contained in 1 mg PLGA was the optimum dosage. These results suggest the new lovastatin-releasing PLGA delivery device exhibits potential for clinical treatment of bony defects.

Managing statin-induced muscle toxicity in a lipid clinic

WHAT IS KNOWN AND OBJECTIVE

Muscle toxicity is the most significant adverse effect related to statins. The aim of the study was to analyse the clinical course and achievement of LDL-C target levels in patients with statin-induced muscle toxicity.

METHODS

All patients who were referred to the lipid clinic because of statin-induced muscle toxicity, or developed it during follow-up, or did not reach LDL-C target levels because of its previous occurrence, and attended the clinic for at least three follow-up visits, were eligible. Files were reviewed for demographic and clinical parameters, coronary heart disease risk level, the severity of muscle injury, the type of statin and dose that caused the adverse effects, the clinical approach and outcome, and whether the LDL-C target level was achieved.

RESULTS

The study group consisted of 54 patients. Twenty-three (43%) patients complained of myalgia, 23 (43%) had asymptomatic serum creatine kinase (CK) level elevation, five (9%) had myopathy and three (5%) had rhabdomyolysis. Fifty of the patients (93%) continued statin therapy and 43 (80%) achieved the LDL-C target level.

WHAT IS NEW AND CONCLUSION

We show that for the majority of patients with statin-induced muscle toxicity, statin therapy can be safely and effectively continued. In cases of asymptomatic CK levels <3-5 upper limit of normal (ULN), statin treatment should not be interrupted. When CK levels >3-5 ULN or when various symptomatic muscle adverse reactions are present, statins rechallenge, after a recovery period, should be individualized either by a low dose of a potent statin or by a less potent statin. An additional lipid medication is advised if the target levels are not achieved.

Role of HMG-CoA reductase inhibitors in neurological disorders : progress to date

Inhibitors of HMG-CoA reductase (statins) are cholesterol-lowering agents that dramatically reduce morbidity and mortality in patients with established cardiovascular disease. In addition, they exhibit pleiotropic effects that operate independently of lipid modification. Statin administration results in greater nitric oxide bioavailability, improved endothelial function, enhanced cerebral blood flow, immune modulation with anti-inflammatory action, decreased platelet aggregation and antioxidant activity. Some or all of these effects may improve outcome or ameliorate symptoms in neurological disorders. This article examines the potential role of statins in treating stroke, Alzheimer's disease, multiple sclerosis and Parkinson's disease. Studies are ongoing in this controversial area, but there are no firm conclusions. The appropriateness of initiating statin therapy for neurological disorders is not established at this time. The exception is stroke, in which recurrence is significantly reduced by statin therapy.

The effect of simvastatin on bone formation and ceramic resorption in a peri-implant defect model

Experimental use of statins as stimulators of bone formation suggests they may have widespread applicability in the field of orthopaedics. With their combined effects on osteoblasts and osteoclasts, statins have the potential to enhance resorption of synthetic materials and improve bone ingrowth. In this study, the effect of oral and local administration of simvastatin to a beta tricalcium phosphate (betaTCP)-filled defect around an implant was compared with recombinant human bone morphogenetic protein 2 (rhBMP2). On hundred and sixty-two Sprague-Dawley rats were assigned to treatment groups: local application of 0.1, 0.9 or 1.7 mg of simvastatin, oral simvastatin at 5, 10 or 50 mg kg(-1) day(-1) for 20 days, local delivery of 1 or 10 microg of rhBMP2, or control. At 6 weeks rhBMP2 increased serum tartrate-resistant acid phosphatase 5b levels and reduced betaTCP area fraction, particle size and number compared with control, suggesting increased osteoclast activity. There was reduced stiffness and increased mechanical strength with this treatment. Local simvastatin resulted in a decreased mineral apposition rate at 6 weeks and increased fibrous area fraction, betaTCP area fraction, particle size and number at 26 weeks. Oral simvastatin had no effect compared with control. Local application of rhBMP2 increased resorption and improved mechanical strength whereas simvastatin was detrimental to healing. Oral simvastatin was ineffective at promoting either ceramic resorption or bone formation. The effect of statins on the repair of bone defects with graft substitute materials is influenced by its bioavailability. Thus, further studies on the optimal delivery system are needed.

Effects of CoQ10 supplementation on plasma lipoprotein lipid, CoQ10 and liver and muscle enzyme levels in hypercholesterolemic patients treated with atorvastatin: A randomized double-blind study

The long-term efficacy and safety of HMG-CoA reductase inhibitors (statins) have been established in large multicenter trials. Inhibition of this enzyme, however, results in decreased synthesis of cholesterol and other products downstream of mevalonate, such as CoQ10 or dolichol. This was a randomized double-blind, placebo-controlled study that examined the effects of CoQ10 and placebo in hypercholesterolemic patients treated by atorvastatin. Eligible patients were given 10mg/day of atorvastatin for 16 weeks. Half of the patients (n=24) were supplemented with 100mg/day of CoQ10, while the other half (n=25) were given the placebo. Serum LDL-C levels in the CoQ10 group decreased by 43%, while in the placebo group by 49%. The HDL-C increment was more striking in the CoQ10 group than in the placebo group. All patients showed definite reductions of plasma CoQ10 levels in the placebo group, by 42%. All patients supplemented with CoQ10 showed striking increases in plasma CoQ10 by 127%. In conclusion atorvastatin definitely decreased plasma CoQ10 levels and supplementation with CoQ10 increased their levels. These changes in plasma CoQ10 levels showed no relation to the changes in serum AST, ALT and CK levels. Further studies are needed, however, for the evaluation of CoQ10 supplementation in statin therapy.

Interaction of cardiovascular risk factors with myocardial ischemia/reperfusion injury, preconditioning, and postconditioning

Therapeutic strategies to protect the ischemic myocardium have been studied extensively. Reperfusion is the definitive treatment for acute coronary syndromes, especially acute myocardial infarction; however, reperfusion has the potential to exacerbate lethal tissue injury, a process termed "reperfusion injury." Ischemia/reperfusion injury may lead to myocardial infarction, cardiac arrhythmias, and contractile dysfunction. Ischemic preconditioning of myocardium is a well described adaptive response in which brief exposure to ischemia/reperfusion before sustained ischemia markedly enhances the ability of the heart to withstand a subsequent ischemic insult. Additionally, the application of brief repetitive episodes of ischemia/reperfusion at the immediate onset of reperfusion, which has been termed "postconditioning," reduces the extent of reperfusion injury. Ischemic pre- and postconditioning share some but not all parts of the proposed signal transduction cascade, including the activation of survival protein kinase pathways. Most experimental studies on cardioprotection have been undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of other disease processes. However, ischemic heart disease in humans is a complex disorder caused by or associated with known cardiovascular risk factors including hypertension, hyperlipidemia, diabetes, insulin resistance, atherosclerosis, and heart failure; additionally, aging is an important modifying condition. In these diseases and aging, the pathological processes are associated with fundamental molecular alterations that can potentially affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Among many other possible mechanisms, for example, in hyperlipidemia and diabetes, the pathological increase in reactive oxygen and nitrogen species and the use of the ATP-sensitive potassium channel inhibitor insulin secretagogue antidiabetic drugs and, in aging, the reduced expression of connexin-43 and signal transducer and activator of transcription 3 may disrupt major cytoprotective signaling pathways thereby significantly interfering with the cardioprotective effect of pre- and postconditioning. The aim of this review is to show the potential for developing cardioprotective drugs on the basis of endogenous cardioprotection by pre- and postconditioning (i.e., drug applied as trigger or to activate signaling pathways associated with endogenous cardioprotection) and to review the evidence that comorbidities and aging accompanying coronary disease modify responses to ischemia/reperfusion and the cardioprotection conferred by preconditioning and postconditioning. We emphasize the critical need for more detailed and mechanistic preclinical studies that examine car-dioprotection specifically in relation to complicating disease states. These are now essential to maximize the likelihood of successful development of rational approaches to therapeutic protection for the majority of patients with ischemic heart disease who are aged and/or have modifying comorbid conditions.

The CADEUS study: methods and logistics

PURPOSE

At the request of the French Health authorities, a study called CADEUS (COX-2 inhibitors and NSAIDs: description of users) aimed to describe the users of cyclo-oxygenase (COX)-2 inhibitors and traditional non-selective non-steroidal anti-inflammatory drugs (tNSAIDs). We report here the methodology, logistics and study design performances.

METHODS

CADEUS is a cohort study designed to include 40,000 patients randomly sampled monthly in the French National Healthcare Insurance database, who received at least one dispensation of celecoxib, rofecoxib or tNSAIDs (1:1:2), from September 2003 to August 2004. Patients and prescribers were asked to fill a questionnaire on indication, medical history, risk factors and hospitalizations since drug acquisition. There was no reminder. For each respondent, healthcare resources used for the 6 months before and after inclusion were extracted from the database. Response rate, response delay, responders and non-responders characteristics were assessed.

RESULTS

Of the 222,879 patients and their prescribers contacted, 20.8% patients and 32.6% prescribers responded. Median response delay was 16 days for patients and 17 days for physicians. Factors associated with patient response were age, cohort, type of prescriber and period of inclusion.

CONCLUSION

This is the first study of this design in France, combining data from a claims database and direct patient and prescriber questionnaires.

Fatal toxic myopathy attributed to propofol, methylprednisolone, and cyclosporine after prior exposure to colchicine and simvastatin

We report a fatal case of toxic myopathy in a patient with a transplanted heart for severe ischemic coronary artery disease. He was on long-term cyclosporine, prednisone, and mycofenolate. Four months before the development of proximal muscle weakness, his simvastatin dose was doubled, and he was also started on colchicine for acute exacerbation of gout. He developed progressive muscle weakness leading to shortness of breath and hospitalization for respiratory failure. Colchicine and simvastatin were stopped on admission. He received high-dose methylprednisolone for continued muscle weakness while he was sedated with propofol. These changes led to a marked elevation of creatine kinase, peaking at 33,580 U/ml. The muscle biopsy revealed toxic vacuolization, mitochondrial damage, and no evidence of inflammation. Based on the timing of events, the combination of propofol, high-dose methylprednisolone, and cyclosporine have triggered rhabdomyolysis, which may have been facilitated by prior administration of colchicine and simvastatin.

Effect of atorvastatin on energy expenditure and skeletal muscle oxidative metabolism at rest and during exercise

Statins are associated with adverse effects in skeletal muscle. This study tested the hypothesis that atorvastatin would increase the respiratory exchange ratio (RER) at rest and during exercise. Twenty-eight healthy subjects (mean age 52 years) were enrolled in a double-blind, placebo-controlled, randomized study of the effects of atorvastatin (40 mg/day) on whole body energetics over 8 weeks. Ventilatory gas exchange measurements, at rest and during bicycle ergometry, were used to assess muscle oxidative metabolism. Thirteen subjects from each treatment arm completed the study. Eight weeks of atorvastatin lowered plasma low-density lipoprotein cholesterol concentration but had no effect on resting or submaximal energy expenditure, RER, or calculated fatty acid oxidation rates. Atorvastatin did not affect maximal exercise oxygen consumption or the anaerobic threshold. Eight weeks of atorvastatin therapy was not associated with alterations in substrate oxidation, or muscle oxidative function at rest, or during exercise in healthy adults.

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 stain myopathy, drug-induced lupus, arthralgias, vasculitis, or tight skin syndromes. This article discusses the possible iatrogenic causes of rheumatic conditions, potential inciting agents, and the various types of rheumatic manifestations seen in the elderly.

Atorvastatin-induced early-onset rhabdomyolysis in a patient with nephrotic syndrome

PURPOSE

A case of early-onset rhabdomyolysis in a patient treated with atorvastatin is described.

SUMMARY

A 17-year-old Indian boy weighing 55 kg was admitted to the hospital after complaining of facial puffiness and pedal edema for four days. His medical history revealed a diagnosis of nephrotic syndrome when he was 2 years old. He had six relapses, the last of which occurred 10 years ago. He was not taking any medications on admission and had not for the past 9 years. His vital signs were normal on admission (day 1), but anasarca was noticed during general examination. Cardiovascular, respiratory, and abdominal examinations were normal. Relapse of nephrotic syndrome was considered, and his 24-hour urine protein value confirmed the diagnosis. Further laboratory tests revealed that the patient had high total and low-density-lipoprotein cholesterol values (597 and 465 mg/dL, respectively), and atorvastatin 10 mg p.o. once daily was initiated on day 2. Prednisolone 60 mg p.o. once daily was initiated on day 3. On day 6, the patient complained of pain in both thighs and had difficulty walking. His creatine kinase (CK) concentration was then measured and found to be elevated (11,821 IU/L). Prednisolone and atorvastatin were then stopped, as statin-induced myopathy was suspected. The patient received i.v. hydration and sodium bicarbonate, and he began to show improvement by day 9. Follow-up three weeks later revealed a normal CK level and no myopathy-related complaints.

CONCLUSION

Early-onset rhabdomyolysis was reported in a patient with nephrotic syndrome who was treated with atorvastatin. Concomitant use of prednisolone and the patient's underlying renal impairment may have predisposed the patient to this adverse reaction.

A lesson for everyone in drug–drug interactions

An 84-year-old man was admitted to the hospital for severe rhabdomyolysis induced by drug-drug interactions between simvastatin and ketoconazole and he recovered completely. Guidelines are suggesting lower goals for low density cholesterol leading to increased statin use. As the population is aging and treated with multiple medications for other co-morbidities, it is imperative for physician to be aware of potential fatal drug-drug interactions, in our case statins, and look for alternatives.

Use of maximum-dose simvastatin or atorvastatin in an ethnically diverse population

PURPOSE

The use of maximum-dose simvastatin or atorvastatin in an ethnically diverse population was studied.

METHODS

This retrospective analysis was conducted at a publicly funded teaching institution whose predominant patient population consists of Hispanics and Asians. A computer-generated report was used to identify outpatients who received a prescription for maximum-dose simvastatin or atorvastatin between January 1, 2002, and January 1, 2004. Data evaluated included demographic information; metabolic syndrome elements; coronary heart disease (CHD) risk equivalents; clinical characteristics placing patients at very high risk of having a CHD event; 10-year Framingham risk score; documentation of hepatotoxicity, myalgia, myositis, or rhabdomyolysis during maximum-dose therapy; concomitant medication during maximumdose therapy; relevant laboratory test values; and physician response to biochemical abnormalities or adverse events associated with maximum-dose therapy.

RESULTS

Of the 232 outpatients identified, 173 were eligible for study inclusion. A total of 135 patients were classified as having a high or very-high risk of developing CHD (68 and 67, respectively). The success rates for low-density-lipoprotein (LDL) cholesterol goal attainment by very-high-risk patients and high-risk patients were 19.4% and 44.1%, respectively. Thirteen patients developed myalgia. Alanine transaminase levels were monitored for 38.8% of the study patients. Approximately 9% of patients were prescribed one interacting medication while on maximum-dose simvastatin or atorvastatin. The most commonly prescribed interacting drug was gemfibrozil.

CONCLUSION

Despite the use of maximum-dose simvastatin or atorvastatin, target LDL cholesterol goals were not achieved and statin use was not adequately monitored in an ethnically diverse population with a high or very high risk of developing CHD.

Lupus erythematosus and other autoimmune diseases related to statin therapy: a systematic review

BACKGROUND

Statins have been increasingly associated with drug-induced autoimmune reactions, including lupus erythematosus.

OBJECTIVE

To identify and determine the clinical and biological characteristics of statin-induced autoimmune reactions.

MATERIAL AND METHODS

The MEDLINE database (1966 to September 2005) was used to identify all reported cases of statin-induced autoimmune diseases. The keywords used were statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, adverse effects, autoimmune disease, lupus erythematosus, dermatomyositis and polymyositis.

RESULTS

Twenty-eight cases of statin-induced autoimmune diseases have been published so far. Systemic lupus erythematosus was reported in 10 cases, subacute cutaneous lupus erythematosus in three cases, dermatomyositis and polymyositis in 14 cases and lichen planus pemphigoides in one case. Autoimmune hepatitis was observed in two patients with systemic lupus erythematosus. The mean time of exposure before disease onset was 12.8+/-18 months; range 1 month-6 years. Systemic immunosuppressive therapy was required in the majority of cases. In many patients, antinuclear antibodies were still positive many months after clinical recovery. A lethal outcome has been recorded in two patients despite aggressive immunosuppressive therapy.

CONCLUSION

Long-term exposure to statins may be associated with drug-induced lupus erythematosus and other autoimmune disorders. Fatal cases have been reported despite early drug discontinuation and aggressive systemic immunosuppressive therapy.

Myotoxicity associated with lipid-lowering drugs

PURPOSE OF REVIEW

Lipid-lowering drugs are associated with myotoxicity, which ranges in severity from myalgias to rhabdomyolysis resulting in renal failure and death. Although rhabdomyolysis is rare, muscle symptoms and serum creatine kinase elevations are sufficiently frequent during the course of lipid-lowering drug therapy to pose diagnostic challenges for the clinician. Progress in our understanding of this form of myotoxicity is reviewed.

RECENT FINDINGS

Muscle pain and weakness are the cardinal symptoms and often interfere with vigorous exercise. These symptoms may occur with or without serum creatine kinase elevations. The risk of myotoxicity is increased by combination statin-fibrate therapy as well as by factors that elevate tissue levels of the lipid-lowering drug, including the dose, drug-drug interactions, and host factors. Underlying neuromuscular diseases may become clinically apparent during statin therapy and may predispose to myotoxicity. The pathophysiology of myotoxicity most probably involves metabolic effects of the statins on the isoprenoid pool and on mitochondrial function.

SUMMARY

Management of myotoxicity requires an evaluation of risk factors prior to prescribing lipid-lowering drugs, attention to muscle symptoms, and withdrawal of drug in the event of significant abnormalities.