Diverse Action of Selected Statins on Skeletal Muscle Cells-An Attempt to Explain the Protective Effect of Geranylgeraniol (GGOH) in Statin-Associated Myopathy (SAM)

Assessment of the Preventive Effect of L-carnitine on Post-statin Muscle Damage in a Zebrafish Model

Statins, such as lovastatin, are lipid-lowering drugs (LLDs) that have been used to treat hypercholesterolaemia, defined as abnormally elevated cholesterol levels in the patient’s blood. Although statins are considered relatively safe and well tolerated, recipients may suffer from adverse effects, including post-statin myopathies. Many studies have shown that supplementation with various compounds may be beneficial for the prevention or treatment of side effects in patients undergoing statin therapy. In our study, we investigated whether L-carnitine administered to zebrafish larvae treated with lovastatin alleviates post-statin muscle damage. We found that exposure of zebrafish larvae to lovastatin caused skeletal muscle disruption observed as a reduction of birefringence, changes in muscle ultrastructure, and an increase in atrogin-1. Lovastatin also affected heart performance and swimming behaviour of larvae. Our data indicated that the muscle-protective effect of L-carnitine is partial. Some observed myotoxic effects, such as disruption of skeletal muscle and increase in atrogin-1 expression, heart contraction could be rescued by the addition of L-carnitine. Others, such as slowed heart rate and reduced locomotion, could not be mitigated by L-carnitine supplementation.

Statin-Associated Myopathy: Emphasis on Mechanisms and Targeted Therapy

Hyperlipidemia is a major risk factor for cardiovascular morbidity and mortality. Statins are the first-choice therapy for dyslipidemias and are considered the cornerstone of atherosclerotic cardiovascular disease (ASCVD) in both primary and secondary prevention. Despite the statin-therapy-mediated positive effects on cardiovascular events, patient compliance is often poor. Statin-associated muscle symptoms (SAMS) are the most common side effect associated with treatment discontinuation. SAMS, which range from mild-to-moderate muscle pain, weakness, or fatigue to potentially life-threatening rhabdomyolysis, are reported by 10% to 25% of patients receiving statin therapy. There are many risk factors associated with patient features and hypolipidemic agents that seem to increase the risk of developing SAMS. Due to the lack of a "gold standard", the diagnostic test for SAMS is based on a clinical criteria score, which is independent of creatine kinase (CK) elevation. Mechanisms that underlie the pathogenesis of SAMS remain almost unclear, though a high number of risk factors may increase the probability of myotoxicity induced by statin therapy. Some of these, related to pharmacokinetic properties of statins and to concomitant therapies or patient characteristics, may affect statin bioavailability and increase vulnerability to high-dose statins.

mTORC2 is an important target for simvastatin-associated toxicity in C2C12 cells and mouse skeletal muscle - Roles of Rap1 geranylgeranylation and mitochondrial dysfunction

Statins decrease the serum LDL-cholesterol concentration and reduce the risk for cardiovascular diseases but can cause myopathy, which may be related to mTORC inhibition. In the current study, we investigated which mTORC is inhibited by simvastatin and by which mechanisms. In C2C12 myoblasts and myotubes and mouse gastrocnemius, simvastatin was cytotoxic and inhibited S6rp and Akt Ser473 phosphorylation, indicating inhibition of mTORC1 and mTORC2, respectively. In contrast to simvastatin, the mTORC1 inhibitor rapamycin did not inhibit mTORC2 activity and was not cytotoxic. Like simvastatin, knock-down of Rictor, an essential component of mTORC2, impaired Akt Ser473 and S6rp phosphorylation and was cytotoxic for C2C12 myoblasts, suggesting that mTORC2 inhibition is an important myotoxic mechanism. The investigation of the mechanism of mTORC2 inhibition showed that simvastatin impaired Ras farnesylation, which was prevented by farnesol but without restoring mTORC2 activity. In comparison, Rap1 knock-down reduced mTORC2 activity and was cytotoxic for C2C12 myoblasts. Simvastatin impaired Rap1 geranylgeranylation and function, which was prevented by geranylgeraniol. In addition, simvastatin and the complex III inhibitor antimycin A caused mitochondrial superoxide accumulation and impaired the activity of mTORC2, which could partially be prevented by the antioxidant MitoTEMPO. In conclusion, mTORC2 inhibition is an important mechanism of simvastatin-induced myotoxicity. Simvastatin inhibits mTORC2 by impairing geranylgeranylation of Rap1 and by inducing mitochondrial dysfunction.

Givinostat as metabolic enhancer reverting mitochondrial biogenesis deficit in Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a rare disorder characterized by progressive muscle wasting, weakness, and premature death. Remarkable progress has been made in genetic approaches, restoring dystrophin, or its function. However, the targeting of secondary pathological mechanisms, such as increasing muscle blood flow or stopping fibrosis, remains important to improve the therapeutic benefits, that depend on tackling both the genetic disease and the downstream consequences. Mitochondrial dysfunctions are one of the earliest deficits in DMD, arise from multiple cellular stressors and result in less than 50% of ATP content in dystrophic muscles. Here we establish that there are two temporally distinct phases of mitochondrial damage with depletion of mitochondrial mass at early stages and an accumulation of dysfunctional mitochondria at later stages, leading to a different oxidative fibers pattern, in young and adult mdx mice. We also observe a progressive mitochondrial biogenesis impairment associated with increased deacetylation of peroxisome proliferator-activated receptor-gamma coactivator 1 α (PGC-1α) promoter. Such histone deacetylation is inhibited by givinostat that positively modifies the epigenetic profile of PGC-1α promoter, sustaining mitochondrial biogenesis and oxidative fiber type switch. We, therefore, demonstrate that givinostat exerts relevant effects at mitochondrial level, acting as a metabolic remodeling agent capable of efficiently promoting mitochondrial biogenesis in dystrophic muscle.

Zebrafish as a Model for the Study of Lipid-Lowering Drug-Induced Myopathies

Drug-induced myopathies are classified as acquired myopathies caused by exogenous factors. These pathological conditions develop in patients without muscle disease and are triggered by a variety of medicaments, including lipid-lowering drugs (LLDs) such as statins, fibrates, and ezetimibe. Here we summarise the current knowledge gained via studies conducted using various models, such as cell lines and mammalian models, and compare them with the results obtained in zebrafish (Danio rerio) studies. Zebrafish have proven to be an excellent research tool for studying dyslipidaemias as a model of these pathological conditions. This system enables in-vivo characterization of drug and gene candidates to further the understanding of disease aetiology and develop new therapeutic strategies. Our review also considers important environmental issues arising from the indiscriminate use of LLDs worldwide. The widespread use and importance of drugs such as statins and fibrates justify the need for the meticulous study of their mechanism of action and the side effects they cause.

Exercise Training Protects against Atorvastatin-Induced Skeletal Muscle Dysfunction and Mitochondrial Dysfunction in the Skeletal Muscle of Rats

Statins are used to prevent and treat atherosclerotic cardiovascular disease, but they also induce myopathy and mitochondrial dysfunction. Here, we investigated whether exercise training prevents glucose intolerance, muscle impairment, and mitochondrial dysfunction in the skeletal muscles of Wistar rats treated with atorvastatin (5 mg kg-1 day-1) for 12 weeks. The rats were assigned to the following three groups: the control (CON), atorvastatin-treated (ATO), and ATO plus aerobic exercise training groups (ATO+EXE). The ATO+EXE group exhibited higher glucose tolerance and forelimb strength and lower creatine kinase levels than the other groups. Mitochondrial respiratory and Ca2+ retention capacity was significantly lower in the ATO group than in the other groups, but exercise training protected against atorvastatin-induced impairment in both the soleus and white gastrocnemius muscles. The mitochondrial H2O2 emission rate was relatively higher in the ATO group and lower in the ATO+EXE group, in both the soleus and white gastrocnemius muscles, than in the CON group. In the soleus muscle, the Bcl-2, SOD1, SOD2, Akt, and AMPK phosphorylation levels were significantly higher in the ATO+EXE group than in the ATO group. In the white gastrocnemius muscle, the SOD2, Akt, and AMPK phosphorylation levels were significantly higher in the ATO+EXE group than in the ATO group. Therefore, exercise training might regulate atorvastatin-induced muscle damage, muscle fatigue, and mitochondrial dysfunction in the skeletal muscles.

Cerivastatin for lowering lipids

BACKGROUND

Cerivastatin was the most potent statin until it was withdrawn from the market due to a number of fatalities due to rhabdomyolysis, however, the dose-related magnitude of effect of cerivastatin on blood lipids is not known.

OBJECTIVES

Primary objective To quantify the effects of various doses of cerivastatin on the surrogate markers: LDL cholesterol, total cholesterol, HDL cholesterol and triglycerides in children and adults with and without cardiovascular disease. The aim of this review is to examine the pharmacology of cerivastatin by characterizing the dose-related effect and variability of the effect of cerivastatin on surrogate markers. Secondary objectives To quantify the effect of various doses of cerivastatin compared to placebo on withdrawals due to adverse effects. To compare the relative potency of cerivastatin with respect to fluvastatin, atorvastatin and rosuvastatin for LDL cholesterol, total cholesterol, HDL cholesterol and triglycerides.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for RCTs up to March 2019: CENTRAL (2019, Issue 3), Ovid MEDLINE, Ovid Embase, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov.We also searched the European Patent Office, FDA.gov, and ProQuest Dissertations & Theses, and contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

RCTs and controlled before-and-after studies evaluating the dose response of different fixed doses of cerivastatin on blood lipids over a duration of three to 12 weeks in participants of any age with and without cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for trials to be included and extracted data. We entered data from RCTs and controlled before-and-after studies into Review Manager 5 as continuous and generic inverse variance data respectively. We collected information on withdrawals due to adverse effects from the RCTs. We assessed all trials using the 'Risk of bias' tool under the categories of sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases.

MAIN RESULTS

Fifty trials (19 RCTs and 31 before-and-after studies) evaluated the dose-related efficacy of cerivastatin in 12,877 participants who had their LDL cholesterol measured. The participants were of any age with and without cardiovascular disease and the trials studied cerivastatin effects within a treatment period of three to 12 weeks. Cerivastatin 0.025 mg/day to 0.8 mg/day caused LDL cholesterol decreases of 11.0% to 40.8%, total cholesterol decreases of 8.0% to 28.8% and triglyceride decreases of 9.0% to 21.4%. We judged the certainty of evidence for these effects to be high. Log dose-response data over doses of 2.5 mg to 80 mg revealed strong linear dose-related effects on LDL cholesterol, total cholesterol and triglycerides. When compared to fluvastatin, atorvastatin and rosuvastatin, cerivastatin was about 250-fold more potent than fluvastatin, 20-fold more potent than atorvastatin and 5.5-fold more potent than rosuvastatin at reducing LDL cholesterol; 233-fold more potent than fluvastatin, 18-fold more potent than atorvastatin and six-fold more potent than rosuvastatin at reducing total cholesterol; and 125-fold more potent than fluvastatin, 11-fold more potent than atorvastatin and 13-fold more potent than rosuvastatin at reducing triglycerides. There was no dose-related effect of cerivastatin on HDL cholesterol, but overall cerivastatin increased HDL cholesterol by 5%. There was a high risk of bias for the outcome withdrawals due to adverse effects, but a low risk of bias for the lipid measurements. Withdrawals due to adverse effects were not different between cerivastatin and placebo in 11 of 19 of these short-term trials (risk ratio 1.09, 95% confidence interval 0.68 to 1.74).

AUTHORS' CONCLUSIONS

The LDL cholesterol, total cholesterol, and triglyceride lowering effect of cerivastatin was linearly dependent on dose. Cerivastatin log dose-response data were linear over the commonly prescribed dose range. Based on an informal comparison with fluvastatin, atorvastatin and rosuvastatin, cerivastatin was about 250-fold more potent than fluvastatin, 20-fold more potent than atorvastatin and 5.5-fold more potent than rosuvastatin in reducing LDL cholesterol, and 233-fold greater potency than fluvastatin, 18-fold greater potency than atorvastatin and six-fold greater potency than rosuvastatin at reducing total cholesterol. This review did not provide a good estimate of the incidence of harms associated with cerivastatin because of the short duration of the trials and the lack of reporting of adverse effects in 42% of the RCTs.