Statin therapy induces ultrastructural damage in skeletal muscle in patients without myalgia

Global consensus on optimal exercise recommendations for enhancing healthy longevity in older adults (ICFSR)

Aging, a universal and inevitable process, is characterized by a progressive accumulation of physiological alterations and functional decline over time, leading to increased vulnerability to diseases and ultimately mortality as age advances. Lifestyle factors, notably physical activity (PA) and exercise, significantly modulate aging phenotypes. Physical activity and exercise can prevent or ameliorate lifestyle-related diseases, extend health span, enhance physical function, and reduce the burden of non-communicable chronic diseases including cardiometabolic disease, cancer, musculoskeletal and neurological conditions, and chronic respiratory diseases as well as premature mortality. Physical activity influences the cellular and molecular drivers of biological aging, slowing aging rates-a foundational aspect of geroscience. Thus, PA serves both as preventive medicine and therapeutic agent in pathological states. Sub-optimal PA levels correlate with increased disease prevalence in aging populations. Structured exercise prescriptions should therefore be customized and monitored like any other medical treatment, considering the dose-response relationships and specific adaptations necessary for intended outcomes. Current guidelines recommend a multifaceted exercise regimen that includes aerobic, resistance, balance, and flexibility training through structured and incidental (integrated lifestyle) activities. Tailored exercise programs have proven effective in helping older adults maintain their functional capacities, extending their health span, and enhancing their quality of life. Particularly important are anabolic exercises, such as Progressive resistance training (PRT), which are indispensable for maintaining or improving functional capacity in older adults, particularly those with frailty, sarcopenia or osteoporosis, or those hospitalized or in residential aged care. Multicomponent exercise interventions that include cognitive tasks significantly enhance the hallmarks of frailty (low body mass, strength, mobility, PA level, and energy) and cognitive function, thus preventing falls and optimizing functional capacity during aging. Importantly, PA/exercise displays dose-response characteristics and varies between individuals, necessitating personalized modalities tailored to specific medical conditions. Precision in exercise prescriptions remains a significant area of further research, given the global impact of aging and broad effects of PA. Economic analyses underscore the cost benefits of exercise programs, justifying broader integration into health care for older adults. However, despite these benefits, exercise is far from fully integrated into medical practice for older people. Many healthcare professionals, including geriatricians, need more training to incorporate exercise directly into patient care, whether in settings including hospitals, outpatient clinics, or residential care. Education about the use of exercise as isolated or adjunctive treatment for geriatric syndromes and chronic diseases would do much to ease the problems of polypharmacy and widespread prescription of potentially inappropriate medications. This intersection of prescriptive practices and PA/exercise offers a promising approach to enhance the well-being of older adults. An integrated strategy that combines exercise prescriptions with pharmacotherapy would optimize the vitality and functional independence of older people whilst minimizing adverse drug reactions. This consensus provides the rationale for the integration of PA into health promotion, disease prevention, and management strategies for older adults. Guidelines are included for specific modalities and dosages of exercise with proven efficacy in randomized controlled trials. Descriptions of the beneficial physiological changes, attenuation of aging phenotypes, and role of exercise in chronic disease and disability management in older adults are provided. The use of exercise in cardiometabolic disease, cancer, musculoskeletal conditions, frailty, sarcopenia, and neuropsychological health is emphasized. Recommendations to bridge existing knowledge and implementation gaps and fully integrate PA into the mainstream of geriatric care are provided. Particular attention is paid to the need for personalized medicine as it applies to exercise and geroscience, given the inter-individual variability in adaptation to exercise demonstrated in older adult cohorts. Overall, this consensus provides a foundation for applying and extending the current knowledge base of exercise as medicine for an aging population to optimize health span and quality of life.

The atorvastatin metabolite pattern in muscle tissue and blood plasma is associated with statin muscle side effects in patients with coronary heart disease; An exploratory case-control study

Background and aims

Statin-associated muscle symptoms (SAMS) is a prevalent cause of statin discontinuation. It is challenging and time-consuming for clinicians to assess whether symptoms are caused by the statin or not, and diagnostic biomarkers are requested. Atorvastatin metabolites have been associated with SAMS. We aimed to compare atorvastatin pharmacokinetics between coronary heart disease (CHD) patients with and without clinically statin intolerance and statin-dependent histopathological alterations in muscle tissue. Secondarily we aimed to assess genetic variants relevant for the observed pharmacokinetic variables.

Methods

Twenty-eight patients with CHD and subjective SAMS were included in the exploratory MUSE biomarker study in 2020. Participants received atorvastatin 40 mg/day for seven weeks followed by no statins for eight weeks. Muscle biopsies and blood were collected at the end of each period. Four patients were categorized as clinically intolerant to ≥3 statins prior to study start whereas four patients had signs of muscle cell damage during treatment.

Results

We found significantly lower levels of atorvastatin acids, and higher lactone/acid ratios in the statin intolerant, both in muscle and plasma. With optimal cut-off, the combination of 2-OH-atorvastatin acid and the 2-OH-atorvastatin lactone/acid ratio provided sensitivity, specificity, and predictive values of 100 %. Patients with variants in UGT1A1 and UGT1A3 had higher lactone metabolite levels than those with wild type, both in muscle and plasma.

Conclusion

Atorvastatin metabolites appear promising as biomarkers for the identification of clinical statin intolerance in patients with self-perceived SAMS, but the findings have to be confirmed in larger studies.

Drug-induced Myopathies

Differential diagnosis of muscle pain and weakness is extensive, including neurological, vertebral, arthrogenic, vascular, traumatic, immunological, endocrine, genetic and infectious aetiologies, as well as medication or toxin-related causes. Muscles are highly sensitive to a large number of drugs, especially with high doses. Although many drug classes can cause toxic myopathy, a significant number of cases are caused by lipid-lowering drugs, long-term use of corticosteroids, and, most often, alcohol misuse. Some drug interactions, e.g. those that are metabolised via the enzyme CYP3A4, can increase the serum levels of the drugs and drug-induced toxicity. A careful history of patient's drug and alcohol consumption is therefore vital. Clinical symptoms depend on the drug, dosage and patient's sensitivity. They can vary from asymptomatic increase in serum levels of creatine kinase, mild myalgia and cramps to muscle weakness, rhabdomyolysis, kidney failure and even death. The pathogenesis is often only partially known and multifactorial. Toxic myopathy is often reversible once the drug is discontinued, alternative drug therapy is started or a different dosage regimen is chosen. Complications such as acute kidney failure must be avoided, and analgesic therapy may be indicated.

Side effects of statins: from pathophysiology and epidemiology to diagnostic and therapeutic implications

Treatment with statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, has proven beneficial preventive effects on cardiovascular events. However, discontinuation due to intolerance and non-adherence remain two of the major gaps in both primary and secondary prevention. This leads many patients with high-risk of atherosclerotic cardiovascular disease (ASCVD) to be inadequately treated or not to achieve target lipid level goals, and as consequence they undergo an increased risk of cardiovascular events. The aim of this review is thus to give an overview of the reasons for discontinuation and on the possible mechanisms behind them. Although statins, as a class, are generally safe, they are associated with an increased risk of diabetes mellitus and hepatic transaminase elevations. Incidence of cataracts or cognitive dysfunction and others presented in the literature (e.g. proteinuria and haematuria) have been never confirmed to have a causal link. Conversely, debated remains the effect on myalgia. Muscle side effects are the most commonly reported, although myalgia is still believed by some to be the result of a nocebo/drucebo effect. Concerning mechanisms behind muscular side effects, no clear conclusions have been reached. Thus, if on one side it is important to identify individuals either at higher risk to develop a side effect, or with confirmed risk factors and conditions of statin intolerance, on the other side alternative strategies should be identified to avoid an increased ASCVD risk.

Cholesterol Management in Neurology: Time for Revised Strategies?

Statin therapy has been extensively evaluated and shown to reduce the incidence of new or recurrent vascular events, ischemic stroke included. As a consequence, each published guideline pushes for lower low-density cholesterol levels in the population at large, recommending increased statin doses and/or adding new cholesterol-lowering molecules. Neurologists find it sometimes difficult to apply these guidelines, having to confront situations such as (1) ischemic strokes, mainly cardioembolic ones, in patients with already low LDL-cholesterol levels; (2) myasthenic patients, whose lifespan has been extended by available treatment, and whose age and cholesterol levels put them at risk for ischemic stroke; (3) patients with myotonic dystrophy, whose disease often associates diabetes mellitus and heart conduction defects, and in whom blood cholesterol management is also not settled. As such, further trials are needed to address these issues.

Statins Induce Locomotion and Muscular Phenotypes in Drosophila melanogaster That Are Reminiscent of Human Myopathy: Evidence for the Role of the Chloride Channel Inhibition in the Muscular Phenotypes

The underlying mechanisms for statin-induced myopathy (SIM) are still equivocal. In this study, we employ Drosophila melanogaster to dissect possible underlying mechanisms for SIM. We observe that chronic fluvastatin treatment causes reduced general locomotion activity and climbing ability. In addition, transmission microscopy of dissected skeletal muscles of fluvastatin-treated flies reveals strong myofibrillar damage, including increased sarcomere lengths and Z-line streaming, which are reminiscent of myopathy, along with fragmented mitochondria of larger sizes, most of which are round-like shapes. Furthermore, chronic fluvastatin treatment is associated with impaired lipid metabolism and insulin signalling. Mechanistically, knockdown of the statin-target Hmgcr in the skeletal muscles recapitulates fluvastatin-induced mitochondrial phenotypes and lowered general locomotion activity; however, it was not sufficient to alter sarcomere length or elicit myofibrillar damage compared to controls or fluvastatin treatment. Moreover, we found that fluvastatin treatment was associated with reduced expression of the skeletal muscle chloride channel, ClC-a (Drosophila homolog of CLCN1), while selective knockdown of skeletal muscle ClC-a also recapitulated fluvastatin-induced myofibril damage and increased sarcomere lengths. Surprisingly, exercising fluvastatin-treated flies restored ClC-a expression and normalized sarcomere lengths, suggesting that fluvastatin-induced myofibrillar phenotypes could be linked to lowered ClC-a expression. Taken together, these results may indicate the potential role of ClC-a inhibition in statin-associated muscular phenotypes. This study underlines the importance of Drosophila melanogaster as a powerful model system for elucidating the locomotion and muscular phenotypes, promoting a better understanding of the molecular mechanisms underlying SIM.

Statin activation of skeletal ryanodine receptors (RyR1) is a class effect but separable from HMG-CoA reductase inhibition

BACKGROUND AND PURPOSE

Statins, inhibitors of HMG-CoA reductase, are mainstay treatment for hypercholesterolaemia. However, muscle pain and weakness prevent many patients from benefiting from their cardioprotective effects. We previously demonstrated that simvastatin activates skeletal ryanodine receptors (RyR1), an effect that could be important in initiating myopathy. Using a range of structurally diverse statin analogues, we examined structural features associated with RyR1 activation, aiming to identify statins lacking this property.

EXPERIMENTAL APPROACH

Compounds were screened for RyR1 activity utilising [3 H]ryanodine binding. Mechanistic insight into RyR1 activity was studied by incorporating RyR1 channels from sheep, mouse or rabbit skeletal muscle into bilayers.

KEY RESULTS

All UK-prescribed statins activated RyR1 at nanomolar concentrations. Cerivastatin, withdrawn from the market due to life-threatening muscle-related side effects, was more effective than currently-prescribed statins and possessed the unique ability to open RyR1 channels independently of cytosolic Ca2+ . We synthesised the one essential structural moiety that all statins must possess for HMG-CoA reductase inhibition, the R-3,5-dihydroxypentanoic acid unit, and it did not activate RyR1. We also identified five analogues retaining potent HMG-CoA reductase inhibition that inhibited RyR1 and four that lacked the ability to modulate RyR1.

CONCLUSION AND IMPLICATIONS

That cerivastatin activates RyR1 most strongly supports the hypothesis that RyR1 activation is implicated in statin-induced myopathy. Demonstrating that statin regulation of RyR1 and HMG-CoA reductase are separable effects will allow the role of RyR1 in statin-induced myopathy to be further elucidated by the tool compounds we have identified, allowing development of effective cardioprotective statins with improved patient tolerance.

The Impact of Age on Statin-Related Glycemia: A Propensity Score-Matched Cohort Study in Korea

The aim of this study was to investigate the influence of statin on glycemic control in different age groups. Patients admitted for suspected or confirmed coronary artery disease between January 2005 and December 2013 in Seoul, Korea were initially enrolled. After propensity score matching, 2654 patients (1:1 statin users and non-users) were selected out of total 5041 patients, including 1477 “young” patients (≤60 y) and 1177 elderly patients (>60 y). HbA1c was decreased by 0.04% (±0.86%) in statin non-users. On the contrary, a slight increment of 0.05% (±0.71%) was found in statin users (p < 0.001). The change patterns of HbA1c were constant in both young and elderly patient groups. Furthermore, elderly statin users demonstrated significantly worse glycemic control in serum insulin and homeostatic model assessment—insulin resistance (HOMA-IR) index. In elderly patients, statin users were found to have a 2.61 ± 8.34 μU/mL increment in serum insulin, whereas it was 2.35 ± 6.72 μU/mL for non-users (p = 0.012). Statin users had a 0.78 ± 3.28 increment in HOMA-IR, in contrast to the 0.67 ± 2.51 increment in statin non-users (p = 0.008). In conclusion, statin treatment was associated with adverse glycemic control in the elderly population.

Plasmonic fusion between fibroblasts and skeletal muscle cells for skeletal muscle regeneration

Normal regeneration of skeletal muscle takes place by the differentiation of muscle-specific stem cells into myoblasts that fuse with existing myofibers for muscle repair. This natural repair mechanism could be ineffective in some cases, for example in patients with genetic muscular dystrophies or massive musculoskeletal injuries that lead to volumetric muscle loss. In this study we utilize the effect of plasmonic cell fusion, i.e. the fusion between cells conjugated by gold nanospheres and irradiated by resonant femtosecond laser pulses, for generating human heterokaryon cells of myoblastic and fibroblastic origin, which further develop into viable striated myotubes. The heterokaryon cells were found to express the myogenic transcription factors MyoD and Myogenin, as well as the Desmin protein that is essential in the formation of sarcomeres, and could be utilized in various therapeutic approaches that involve transplantation of cells or engineered tissue into the damaged muscle.

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.

Cutaneous involvement in anti-HMGCR positive necrotizing myopathy

OBJECTIVE

Anti-3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) positive immune-mediated necrotizing myopathy (IMNM) is a rare disease. It is induced by exogenous substances, most often by statins. Little is known about cutaneous manifestations of HMGCR positive IMNM and about HMGCR antibody positivity in other diseases.

METHODS

The characteristics of patients with anti-HMGCR autoantibodies measured at our laboratory between January 2012 and September 2020 were studied. Characteristics of patients with IMNM were compared to those patients with positive antibodies but without muscle involvement. Associations of IMNM with other organ involvements were searched for.

RESULTS

Of the 32 patients studied, 23 showed characteristics of IMNM, 9 did not fulfill current classification criteria but most showed signs of connective tissue diseases. Patients with IMNM were older (66 and 35 years, respectively; 0.92 (0.73-0.98); p < 0.001), had more frequent statin exposure (87% and 33%, respectively; 0.84 (0.61-0.94); p = 0.005) and higher mean peak CK (8717U/l and 329U/l, respectively; 1.0 (0.85-1.0); p < 0.001). 13/23 (56%) of IMNM patients showed cutaneous lesions; none of the patients suffered from cancer; only three IMNM patients showed drug-free complete remission. Incidence of IMNM in the catchment area of our center is at least 2.7/Mio/year.

CONCLUSION

Cutaneous lesions were found to be more frequent in anti-HMRCR positive IMNM than previously reported. Titer of anti-HMGCR antibodies and CK levels were significantly higher in IMNM than in other autoimmune connective tissue diseases. The data support the hypothesis of an antigen-driven response in IMNM, and suggests an activation of autoreactive B-lymphocytes in non-IMNM patients.

Excessive expression of miR-1a by statin causes skeletal injury through targeting mitogen-activated protein kinase kinase kinase 1

Backgrounds: A major side effect of statin, a widely used drug to treat hyperlipidemia, is skeletal myopathy through cell apoptosis. The aim of this study is to investigate the roles of microRNA in statin-induced injury.

Methods: Apolipoprotein E knockout (ApoE-/-) mice were administered with simvastatin (20 mg/kg/day) for 8 weeks. Exercise capacity was evaluated by hanging grid test, forelimb grip strength, and running tolerance test.

Results: In cultured skeletal muscle cells, statin increased the levels of miR-1a but decreased the levels of mitogen-activated protein kinase kinase kinase 1 (MAP3K1) in a time or dose dependent manner. Both computational target-scan analysis and luciferase gene reporter assay indicated that MAP3K1 is the target gene of miR-1a. Statin induced cell apoptosis of skeletal muscle cells, but abolished by downregulating of miR-1a or upregulation of MAP3K1. Further, the effects of miR-1a inhibition on statin-induced cell apoptosis were ablated by MAP3K1 siRNA. In ApoE-/- mice, statin induced cell apoptosis of skeletal muscle cells and decreased exercise capacity in mice infected with vector, but not in mice with lentivirus-mediated miR-1a gene silence.

Conclusion: Statin causes skeletal injury through induction of miR-1a excessive expression to decrease MAP3K1 gene expression.

Statin-Induced Myopathy: Translational Studies from Preclinical to Clinical Evidence

Statins are the most prescribed and effective drugs to treat cardiovascular diseases (CVD). Nevertheless, these drugs can be responsible for skeletal muscle toxicity which leads to reduced compliance. The discontinuation of therapy increases the incidence of CVD. Thus, it is essential to assess the risk. In fact, many studies have been performed at preclinical and clinical level to investigate pathophysiological mechanisms and clinical implications of statin myotoxicity. Consequently, new toxicological aspects and new biomarkers have arisen. Indeed, these drugs may affect gene transcription and ion transport and contribute to muscle function impairment. Identifying a marker of toxicity is important to prevent or to cure statin induced myopathy while assuring the right therapy for hypercholesterolemia and counteracting CVD. In this review we focused on the mechanisms of muscle damage discovered in preclinical and clinical studies and highlighted the pathological situations in which statin therapy should be avoided. In this context, preventive or substitutive therapies should also be evaluated.

Pathophysiological mechanisms of statin-associated myopathies: possible role of the ubiquitin-proteasome system

BACKGROUND

Statins are the cornerstone of pharmacotherapy for atherosclerotic cardiovascular disease. While these drugs are generally safe, treatment adherence is not optimal in a considerable proportion of patients because of the adverse effects on skeletal muscles in the forms of myopathy, myalgia, muscular pain, nocturnal muscle cramping, weakness, and rare rhabdomyolysis.

METHODS

For the purpose of this narrative review, we searched for the literature suggesting the involvement of the ubiquitin-proteasome system in the development of statin-induced myopathy.

RESULTS

Statins have been shown to up-regulate the expression of the muscle-specific ubiquitin-proteasome system as the major non-lysosomal intracellular protein degradation system. It has been postulated that statins may provoke instability in the myocyte cell membrane when subjected to eccentric exercise stress, triggering activation of intracellular proteolytic cascades and changes in protein degradation machinery. This is accompanied by the up-regulation of a series of genes implicated in protein catabolism, in addition to those of the ubiquitin-proteasome system.

CONCLUSIONS

Based on the available literature, it seems that the involvement of ubiquitin-proteasome system is potentially implicated in the pathophysiology of statin-induced myopathy.

Safety and Efficacy of Pitavastatin in Patients With Impaired Fasting Glucose and Hyperlipidemia: A Randomized, Open-labeled, Multicentered, Phase IV Study

PURPOSE

Although the role of high-intensity lipid-lowering therapy in cardiovascular protection has broadened, concerns still exist about new-onset diabetes mellitus (NODM), especially in vulnerable patients. This study aimed to compare the effect of high-dose (4 mg/d) and usual dose (2 mg/d) pitavastatin on glucose metabolism in patients with hyperlipidemia and impaired fasting glucose (IFG).

METHODS

In this 12-month study, glucose tolerance and lipid-lowering efficacy of high-dose pitavastatin (4 mg [study group]) was compared with that of usual dose pitavastatin (2 mg [control group]) in patients with hyperlipidemia and IFG. The primary end point was the change of glycosylated hemoglobin (HbA_1c) after 24 weeks of treatment. The secondary end points were as follows: (1) NODM within 1 year after treatment, (2) change of lipid parameters, (3) changes of adiponectin, and (4) change of blood glucose and insulin levels.

FINDINGS

Of the total 417 patients screened, 313 patients with hypercholesterolemia and IFG were randomly assigned into groups. The mean (SD) change in HbA_1c was 0.06% (0.20%) in the study group and 0.03% (0.22%) in the control group (P = 0.27). Within 1 year, 27 patients (12.3%) developed NODM, including 12 (10.6%) of 113 patients in the study group and 15 (14.2%) of 106 in the control group (P = 0.43). The study group had a significantly higher reduction of total cholesterol and LDL-C levels and a higher increase in apolipoprotein A1/apolipoprotein B ratio (0.68 [0.40] vs 0.51 [0.35], P < 0.01).

IMPLICATIONS

The high-dose pitavastatin therapy did not aggravate glucose metabolism compared with the usual dose therapy. Moreover, it had a better effect on cholesterol-lowering and apolipoprotein distribution in the patients with hyperlipidemia and IFG.

Effect of Vitamin D Analogue on Rosuvastatin-Induced Myopathy in Wistar Rats

OBJECTIVES

Statin-induced myopathy is one of the major causes of poor adherence and discontinuation of this medication. There are contrary results regarding association of vitamin D insufficiency with statin-induced myopathy. This study was done to determine the effect of the vitamin D3 analogue alfacalcidol on Rosuvastatin-induced myopathy in rats. Methodology. Animals were divided into six groups with 6 rats in each group. Groups I and II acted as controls, Group III and Group IV were administered Rosuvastatin 120 mg/kg/day and 160 mg/kg/day, Groups V and VI were administered alfacalcidol 0.1 μg/kg/day in addition to Rosuvastatin 120 mg/kg/day and 160 mg/kg/day, respectively. All drugs were administered orally for 15 days. Plasma creatine kinase (CK) levels were estimated on day 10 and day 15. Animals were sacrificed and muscles were sent for histopathological examination.

RESULTS

On day 10, Groups V and VI showed a statistically significant increase in plasma CK levels as compared to the control (p < 0.001) and were significantly lower (p < 0.001) as compared to Groups III and IV, respectively. However, on day 15, plasma CK levels in Groups V and VI were comparable to those of control groups with a nonsignificant difference (p > 0.05). On comparing the histology, Groups V and VI showed a significant difference as compared to statin-only groups (Groups III and IV) as there were signs of regeneration, less splitting, and fragmentation of muscle fibres.

CONCLUSION

The present study shows that the vitamin D analogue alfacalcidol prevents statin-induced myopathy. The serum CK levels are comparable to the control group on day 15 of vitamin D administration.

A Pharmacogenomic Dissection of a Rosuvastatin-Induced Rhabdomyolysis Case Evokes the Polygenic Nature of Adverse Drug Reactions

Rosuvastatin, is a widely-used statin for the treatment of hypercholesterolemia and the prevention of cardiovascular diseases. Although rosuvastatin is well tolerated, about 3/10.000 patients can suffer severe myopathy. Rhabdomyolysis is a severe medical condition that causes injury to the skeletal muscle, electrolyte imbalances, acute renal failure and extreme creatine kinase (CK) elevation. Little is known regarding the molecular involvement of rosuvastatin-induced rhabdomyolysis (RIR). It has been demonstrated that genomic variants associated with decreased enzymatic activity of proteins are important determinants in plasmatic and skeletal muscle distribution of rosuvastatin and its toxicity. Until now, no interactions of ticagrelor, ezetimibe and rosuvastatin have been described with the consideration of pharmacogenomics predisposition. The present report involves a whole-exome sequencing (WES), in a patient affected by rosuvastatin-induced rhabdomyolysis. A pharmacogenomic dissection was performed by analyzing a comprehensive subset of candidate genes (n=160) potentially related to RIR. The genes were selected according to their implication in drug metabolism or inherited myopathies. Using an innovative approach of bioinformatics analysis, considering rare and common variants, we identified 19 genomic variations potentially related to the pharmacokinetic/pharmacodynamic modifications of rosuvastatin, ezetimibe and ticagrelor. The affected genes are involved in Phase I metabolism (CYP2C19, CYP2E1, CYP1A1, CYP2D6 and CYP2C9), Phase II metabolism (UGT2B15 and UGT2B7), influx transportation (SLCO1B3 and SLCO2B1), efflux transportation (ABCG8, ABCB11, ABCC4 and ABCB1), drug targeting (NPC1L1) and inherited myopathy etiology (OBSCN). We report three rare, potentially pathogenic molecular variants in CYP2C19, NPC1L1 and OBSCN genes. Pharmacogenetic analysis indicated that the patient was a carrier of inactivating alleles in several pharmacogenes involved in drug toxicity. The whole-exome sequencing and bioinformatics analysis presented here represents an innovative way to identify genomic variants contributing with RIR´s origin and evokes the polygenic nature of adverse drug reactions.

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.

Statin-Related Myotoxicity: A Comprehensive Review of Pharmacokinetic, Pharmacogenomic and Muscle Components

Statins are a cornerstone in the pharmacological prevention of cardiovascular disease. Although generally well tolerated, a small subset of patients experience statin-related myotoxicity (SRM). SRM is heterogeneous in presentation; phenotypes include the relatively more common myalgias, infrequent myopathies, and rare rhabdomyolysis. Very rarely, statins induce an anti-HMGCR positive immune-mediated necrotizing myopathy. Diagnosing SRM in clinical practice can be challenging, particularly for mild SRM that is frequently due to alternative aetiologies and the nocebo effect. Nevertheless, SRM can directly harm patients and lead to statin discontinuation/non-adherence, which increases the risk of cardiovascular events. Several factors increase systemic statin exposure and predispose to SRM, including advanced age, concomitant medications, and the nonsynonymous variant, rs4149056, in SLCO1B1, which encodes the hepatic sinusoidal transporter, OATP1B1. Increased exposure of skeletal muscle to statins increases the risk of mitochondrial dysfunction, calcium signalling disruption, reduced prenylation, atrogin-1 mediated atrophy and pro-apoptotic signalling. Rare variants in several metabolic myopathy genes including CACNA1S, CPT2, LPIN1, PYGM and RYR1 increase myopathy/rhabdomyolysis risk following statin exposure. The immune system is implicated in both conventional statin intolerance/myotoxicity via LILRB5 rs12975366, and a strong association exists between HLA-DRB1*11:01 and anti-HMGCR positive myopathy. Epigenetic factors (miR-499-5p, miR-145) have also been implicated in statin myotoxicity. SRM remains a challenge to the safe and effective use of statins, although consensus strategies to manage SRM have been proposed. Further research is required, including stringent phenotyping of mild SRM through N-of-1 trials coupled to systems pharmacology omics- approaches to identify novel risk factors and provide mechanistic insight.

Mitochondrial disorders and the eye

Mitochondria are cellular organelles that play a key role in energy metabolism and oxidative phosphorylation. Malfunctioning of mitochondria has been implicated as the cause of many disorders with variable inheritance, heterogeneity of systems involved, and varied phenotype. Metabolically active tissues are more likely to be affected, causing an anatomic and physiologic disconnect in the treating physicians' mind between presentation and underlying pathophysiology. We shall focus on disorders of mitochondrial metabolism relevant to an ophthalmologist. These disorders can affect all parts of the visual pathway (crystalline lens, extraocular muscles, retina, optic nerve, and retrochiasm). After the introduction reviewing mitochondrial structure and function, each disorder is reviewed in detail, including approaches to its diagnosis and most current management guidelines.

Muscle Toxicity of Drugs: When Drugs Turn Physiology into Pathophysiology

Drugs are prescribed to manage or prevent symptoms and diseases, but may sometimes cause unexpected toxicity to muscles. The symptomatology and clinical manifestations of the myotoxic reaction can vary significantly between drugs and between patients on the same drug. This poses a challenge on how to recognize and prevent the occurrence of drug-induced muscle toxicity. The key to appropriate management of myotoxicity is prompt recognition that symptoms of patients may be drug related and to be aware that inter-individual differences in susceptibility to drug-induced toxicity exist. The most prevalent and well-documented drug class with unintended myotoxicity are the statins, but even today new classes of drugs with unintended myotoxicity are being discovered. This review will start off by explaining the principles of drug-induced myotoxicity and the different terminologies used to distinguish between grades of toxicity. The main part of the review will focus on the most important pathogenic mechanisms by which drugs can cause muscle toxicity, which will be exemplified by drugs with high risk of muscle toxicity. This will be done by providing information on key clinical and laboratory aspects, muscle electromyography patterns and biopsy results, and pathological mechanism and management for a specific drug from each pathogenic classification. In addition, rather new classes of drugs with unintended myotoxicity will be highlighted. Furthermore, we will explain why it is so difficult to diagnose drug-induced myotoxicity, and which tests can be used as a diagnostic aid. Lastly, a brief description will be given of how to manage and treat drug-induced myotoxicity.

Statin Toxicity

There is now overwhelming evidence to support lowering LDL-c (low-density lipoprotein cholesterol) to reduce cardiovascular morbidity and mortality. Statins are a class of drugs frequently prescribed to lower cholesterol. However, in spite of their wide-spread use, discontinuation and nonadherence remains a major gap in both the primary and secondary prevention of atherosclerotic cardiovascular disease. The major reason for statin discontinuation is because of the development of statin-associated muscle symptoms, but a range of other statin-induced side effects also exist. Although the mechanisms behind these side effects have not been fully elucidated, there is an urgent need to identify those at increased risk of developing side effects as well as provide alternative treatment strategies. In this article, we review the mechanisms and clinical importance of statin toxicity and focus on the evaluation and management of statin-associated muscle symptoms.

Statin-induced muscular side effects at rest and exercise - An anatomical mapping

BACKGROUND AND AIMS

Muscle-related symptoms with or without creatine kinase (CK) elevation are common adverse effects associated with statin use. Symptoms are ranging from benign myalgia to myositis and in rare cases to rhabdomyolysis. The aim was to characterize and describe muscular side effects and create an anatomical frequency mapping.

METHODS

The prospective observational study was performed at a large lipidology outpatient unit in Vienna. 1111 consecutively admitted patients with muscular side effects on statin monotherapy were included during a 4-year period. Anatomical mapping of the affected muscles, signs and symptoms, the onset of symptoms after starting statin therapy and disappearance after cessation of treatment was assessed.

RESULTS

In 96.5% of the patients with muscle symptoms, there was no elevation of CK. The anatomical mapping revealed exercised muscles as being mainly affected in 84%. In the upper extremity, symptoms were mainly described at the dominating side. Mostly affected muscles were the pectoral (61.4%), followed by the quadriceps femoris (59.8%), the biceps brachii (54.3%) and the deltoid (22.5%) muscles. The majority of symptoms (76.9%, n = 854) appeared within 29 days. Symptoms disappeared after discontinuation of statin therapy at a mean of 5.4 days.

CONCLUSIONS

Physical activity seems to be a key trigger for onset of statin-induced muscular side effects. The appearance of symptoms can be symmetrical, asymmetrical, generalized or in isolated muscle groups only. Different statins usually produce similar symptoms, but often some patients tolerate one statin better than another.

Development of AD-Like Pathology in Skeletal Muscle

Effective therapeutic strategy against Alzheimer's disease (AD) requires early detection of AD; however, clinical diagnosis of Alzheimer's disease (AD) is not precise and a definitive diagnosis of AD is only possible via postmortem examination for AD pathological hallmarks including senile plaques composed of Aβ and neuro fibrillary tangles composed of phosphorylated tau. Although a variety of biomarker has been developed and used in clinical setting, none of them robustly predicts subsequent clinical course of AD. Thus, it is essential to identify new biomarkers that may facilitate the diagnosis of early stages of AD, prediction of subsequent clinical course, and development of new therapeutic strategies. Given that pathological hallmarks of AD including Aβaccumulation and the presence of phosphorylated tau are also detected in peripheral tissues, AD is considered a systemic disease. Without the protection of blood-brain barrier, systemic factors can affect peripheral tissues much earlier than neurons in brain. Here, we will discuss the development of AD-like pathology in skeletal muscle and the potential use of skeletal muscle biopsy (examination for Aβaccumulation and phosphorylated tau) as a biomarker for AD.

Fast skeletal troponin I, but not the slow isoform, is increased in patients under statin therapy: a pilot study

Introduction

Statin therapy is often associated with muscle complaints and increased serum creatine kinase (CK). However, although essential in determining muscle damage, this marker is not specific for skeletal muscle. Recent studies on animal models have shown that slow and fast isoforms of skeletal troponin I (ssTnI and fsTnI, respectively) can be useful markers of skeletal muscle injury. The aim of this study was to evaluate the utility of ssTnI and fsTnI as markers to monitor the statin-induced skeletal muscle damage.

Materials and methods

A total of 51 patients (14 using and 37 not using statins) admitted to the intensive care unit of the University of Ferrara Academic Hospital were included in this observational study. Serum activities of CK, aldolase, alanine aminotransferase and myoglobin were determined by spectrophotometric assays or routine laboratory analysis. Isoforms ssTnI and fsTnI were determined by commercially available ELISAs. The creatine kinase MB isoform (CK-MB) and cardiac troponin I (cTnI) were evaluated as biomarkers of cardiac muscle damage by automatic analysers.

Results

Among the non-specific markers, only CK was significantly higher in statin users (P = 0.027). Isoform fsTnI, but not ssTnI, was specifically increased in those patients using statins (P = 0.009) evidencing the major susceptibility of fast-twitch fibres towards statins. Sub-clinical increase in fsTnI, but not CK, was more frequent in statin users (P = 0.007). Cardiac markers were not significantly altered by statins confirming the selectivity of the effect on skeletal muscle.

Conclusions

Serum fsTnI could be a good marker for monitoring statin-associated muscular damage outperforming traditional markers.

Cholesterol Protects Against Acute Stress-Induced T-Tubule Remodeling in Mouse Ventricular Myocytes

Efficient excitation-contraction coupling in ventricular myocytes depends critically on the presence of the t-tubular network. It has been recently demonstrated that cholesterol, a major component of the lipid bilayer, plays an important role in long-term maintenance of the integrity of t-tubular system although mechanistic understanding of underlying processes is essentially lacking. Accordingly, in this study we investigated the contribution of membrane cholesterol to t-tubule remodeling in response to acute hyposmotic stress. Experiments were performed using isolated left ventricular cardiomyocytes from adult mice. Depletion and restoration of membrane cholesterol was achieved by applying methyl-β-cyclodextrin (MβCD) and water soluble cholesterol (WSC), respectively, and t-tubule remodeling in response to acute hyposmotic stress was assessed using fluorescent dextran trapping assay and by measuring t-tubule dependent I_K1 tail current (I_K1,tail). The amount of dextran trapped in t-tubules sealed in response to stress was significantly increased when compared to control cells, and reintroduction of cholesterol to cells treated with MβCD restored the amount of trapped dextran to control values. Alternatively, application of WSC to normal cells significantly reduced the amount of trapped dextran further suggesting the protective effect of cholesterol. Importantly, modulation of membrane cholesterol (without osmotic stress) led to significant changes in various parameters of I_K1, _tail strongly suggesting significant but essentially hidden remodeling of t-tubules prior to osmotic stress. Results of this study demonstrate that modulation of the level of membrane cholesterol has significant effects on the susceptibility of cardiac t-tubules to acute hyposmotic stress.

Association of Statin Use with Increased Risk of Musculoskeletal Conditions: A Retrospective Cohort Study

INTRODUCTION

Musculoskeletal conditions, including osteoarthritis (OA), result in tremendous disability and cost. Statins are among the most commonly prescribed medications and their use for primary prevention in many otherwise healthy individuals, including those who are physically active, is increasing. There is conflicting evidence regarding the relationship of statin use and musculoskeletal conditions. Given the rising disability associated with musculoskeletal conditions, understanding predisposing factors, including medication-related exposures, deserves further attention.

OBJECTIVES

We examined the association between statin use and the risk of being diagnosed with non-traumatic arthropathies, use-related injury, and undergoing rehabilitation in a cohort with longitudinal follow-up.

METHODS

Patients enrolled in a regional military healthcare system between 2003 and 2012 were evaluated in this retrospective cohort study. A propensity score was generated to match statin-users and nonusers using 115 baseline characteristics. Outcomes included ICD-9 diagnoses codes for Agency for Healthcare Research and Quality disease categories of: non-traumatic arthropathies, use-related injury and undergoing rehabilitation. Primary analysis examined the outcomes in statin-users and nonusers after propensity score matching using conditional logistic regression analysis.

RESULTS

Initially, 60,455 patients were identified. We propensity score-matched 6728 statin users with 6728 nonusers (52 years of age, ~ 47% women). In the propensity score-matched cohort, non-traumatic arthropathies occurred in 59.8% of statin users and 56.0% of nonusers [odds ratio (OR) 1.17, 95% confidence interval (95% CI) 1.09-1.25] and use related injury occurred in 31.9% of statin users and 29.8% of nonusers (OR 1.11, 95% CI 1.03-1.19). There was no difference between statin users and nonusers undergoing rehabilitation (22.6% among statin users, 21.9% among nonusers, OR 1.04, 95% CI 0.96-1.13).

CONCLUSION

Statin use was associated with a significant increased risk of non-traumatic arthropathies and use-related injury. Our results provide additional data that can inform patient and clinician conversations about the benefits and risks of statin use.

COQ2 polymorphisms are not associated with increased risk of statin-induced myalgia/myopathy in the Czech population

BACKGROUND

The gene COQ2, encoding 4-hydroxybenzoate-polyprenyltransferase (coenzyme Q2), belongs to the candidates potentially influencing statin treatment tolerability. This enzyme is involved in the biosynthesis of coenzyme Q10 (CoQ10), in which depletion induced by statin treatment is implicated in the development of statin-associated muscle symptoms (SAMS). Thus, polymorphisms in the COQ2 gene might explain susceptibility to SAMS.

METHODS

Adult patients with SAMS (on low doses of atorvastatin and simvastatin)-induced myalgia/myopathy (n=278), patients on statins but without SAMS (n=293) and population (part of the post-MONICA [Multinational MONItoring of trends and determinants in CArdiovascular disease] study) controls (n=561) were genotyped (polymerase chain reaction-restriction fragment length polymorphism [PCR-RFLP] assay) for rs6535454 and rs4693075 polymorphisms within the COQ2 gene loci.

RESULTS

Distribution of rs6535454 in patients with SAMS (GG=51.1%, GA=40.0%, AA=8.9%) did not significantly differ (p=0.33; respectively 0.32 for codominant models of the analysis) from that in the population controls (GG=48.1%, GA=45.0%, AA=6.9%) or the SAMS-unaffected patients (GG=49.8%, GA=40.3%, AA=9.7%). Similarly, neither rs4693075 was associated with SAMS (CC=36.8%, CG=48.2%, GG=15.0% in patients suffering SAMS vs. CC=36.6%, CG=47.5%, GG=15.9 in controls and CC=35.8%, CG=48.2%, GG=15.9% in symptom-free patients, p=0.94 and 0.95 for codominant models of the analysis). Also, the haplotype distributions were not significantly different between the groups analyzed.

CONCLUSIONS

The polymorphisms of the COQ2 gene do not associate with SAMS in the Czech patients treated with low doses of statins. This is another clue that the coenzyme Q10 pathway is not the most important for the development of SAMS.

Host-Derived Microvesicles Carrying Bacterial Pore-Forming Toxins Deliver Signals to Macrophages: A Novel Mechanism of Shaping Immune Responses

Bacterial infectious diseases are a leading cause of death. Pore-forming toxins (PFTs) are important virulence factors of Gram-positive pathogens, which disrupt the plasma membrane of host cells and can lead to cell death. Yet, host defense and cell membrane repair mechanisms have been identified: i.e., PFTs can be eliminated from membranes as microvesicles, thus limiting the extent of cell damage. Released into an inflammatory environment, these host-derived PFTs-carrying microvesicles encounter innate immune cells as first-line defenders. This study investigated the impact of microvesicle- or liposome-sequestered PFTs on human macrophage polarization in vitro. We show that microvesicle-sequestered PFTs are phagocytosed by macrophages and induce their polarization into a novel CD14⁺MHCII^lowCD86^low phenotype. Macrophages polarized in this way exhibit an enhanced response to Gram-positive bacterial ligands and a blunted response to Gram-negative ligands. Liposomes, which were recently shown to sequester PFTs and so protect mice from lethal bacterial infections, show the same effect on macrophage polarization in analogy to host-derived microvesicles. This novel type of polarized macrophage exhibits an enhanced response to Gram-positive bacterial ligands. The specific recognition of their cargo might be of advantage in the efficiency of targeted bacterial clearance.

Sources of Inter-individual Variability in the Therapeutic Response of Blood Glucose Control to Exercise in Type 2 Diabetes: Going Beyond Exercise Dose

In the context of type 2 diabetes, inter-individual variability in the therapeutic response of blood glucose control to exercise exists to the extent that some individuals, occasionally referred to as “non-responders,” may not experience therapeutic benefit to their blood glucose control. This narrative review examines the evidence and, more importantly, identifies the sources of such inter-individual variability. In doing so, this review highlights that no randomized controlled trial of exercise has yet prospectively measured inter-individual variability in blood glucose control in individuals with prediabetes or type 2 diabetes. Of the identified sources of inter-individual variability, neither has a prospective randomized controlled trial yet quantified the impact of exercise dose, exercise frequency, exercise type, behavioral/environmental barriers, exercise-meal timing, or anti-hyperglycemic drugs on changes in blood glucose control, in individuals with prediabetes or type 2 diabetes. In addition, there is also an urgent need for prospective trials to identify molecular or physiological predictors of inter-individual variability in the changes in blood glucose control following exercise. Therefore, the narrative identifies critical science gaps that must be filled if exercise scientists are to succeed in optimizing health care policy recommendations for type 2 diabetes, so that the therapeutic benefit of exercise may be maximized for all individuals with, or at risk of, diabetes.

Histopathologic and Biochemical Evidence for Mitochondrial Disease Among 279 Patients with Severe Statin Myopathy

BACKGROUND

Statins have well-known benefits in the prevention of cardiovascular disease, however, 7-29% of patients develop muscle side effects and up to 0.5% develop severe symptoms. Mitochondrial dysfunction has been associated with severe statin-induced myopathy (SM); however, there is a paucity of systematic studies in affected individuals.

OBJECTIVES

The goal of this study was to combine clinical and laboratory features with quantitative biochemical and histopathologic studies of skeletal muscle biopsies from SM cases to determine what proportion could be attributed to mitochondrial dysfunction and how many of these had primary respiratory chain defects.

METHODS

A retrospective analysis was performed on patient records derived from 279 SM patients whose muscle biopsies were referred to our clinical diagnostic laboratory for analysis. Clinical, histopathologic and biochemical features were compared with two myopathic control groups unexposed to statins: individuals with idiopathic mitochondrial myopathy (MMP; n = 94) and with unknown metabolic myopathy (UMP; n = 86); normal controls were unavailable for this record review study.

RESULTS

More SM patients had significantly elevated plasma CK than in the other two groups (p < 0.01). A subset of SM patients (67 of 279; 24%) had histopathologic and/or electron microscopic (EM) evidence for mitochondrial dysfunction in skeletal muscle; more cases were identified by EM than by histochemical analysis. Of 279 cases, 29 (10%) were confirmed to have respiratory chain defects by biochemical analysis; 4 of these had mitochondrial abnormalities by EM. An additional 20 cases had mitochondrial abnormalities by EM without a biochemical diagnosis.

CONCLUSIONS

Both primary and secondary mitochondrial dysfunction was found in subsets of SM patients. The fact that respiratory chain defects were not found in most cases with histopathologic mitochondrial abnormalities does not rule out primary mitochondrial disease in these cases, however, it is more likely that secondary effects on mitochondrial structure and function have occurred; molecular analysis may be helpful only in a small number of cases.

A common missense variant of LILRB5 is associated with statin intolerance and myalgia

Aims

A genetic variant in LILRB5 (leukocyte immunoglobulin-like receptor subfamily-B) (rs12975366: T > C: Asp247Gly) has been reported to be associated with lower creatine phosphokinase (CK) and lactate dehydrogenase (LDH) levels. Both biomarkers are released from injured muscle tissue, making this variant a potential candidate for susceptibility to muscle-related symptoms. We examined the association of this variant with statin intolerance ascertained from electronic medical records in the GoDARTS study.

Methods and results

In the GoDARTS cohort, the LILRB5 Asp247 variant was associated with statin intolerance (SI) phenotypes; one defined as having raised CK and being non-adherent to therapy [odds ratio (OR) 1.81; 95% confidence interval (CI): 1.34-2.45] and the other as being intolerant to the lowest approved dose of a statin before being switched to two or more other statins (OR 1.36; 95% CI: 1.07-1.73). Those homozygous for Asp247 had increased odds of developing both definitions of intolerance. Importantly the second definition did not rely on CK elevations. These results were replicated in adjudicated cases of statin-induced myopathy in the PREDICTION-ADR consortium (OR1.48; 95% CI: 1.05-2.10) and for the development of myalgia in the JUPITER randomized clinical trial of rosuvastatin (OR1.35, 95% CI: 1.10-1.68). A meta-analysis across the studies showed a consistent association between Asp247Gly and outcomes associated with SI (OR1.34; 95% CI: 1.16-1.54).

Conclusion

This study presents a novel immunogenetic factor associated with statin intolerance, an important risk factor for cardiovascular outcomes. The results suggest that true statin-induced myalgia and non-specific myalgia are distinct, with a potential role for the immune system in their development. We identify a genetic group that is more likely to be intolerant to their statins.

Pleiotropic effects of metformin to rescue statin-induced muscle injury and insulin resistance: A proposed mechanism and potential clinical implications

The 2013 American Heart Association Blood Cholesterol Guidelines increased the number of patients recommended for statin therapy in the United States to 56million. Two common statin side effects are muscle pain, referred to as "statin-associated muscle symptoms", and increased risk for new onset type-2-diabetes mellitus. Up to 25% of statin users report muscle symptoms resulting in many patients being switched to lower dose or lower potency statins, or refusing statins altogether. The most likely signaling mechanisms for statin-associated muscle symptoms overlaps with the proposed mechanism of statin-induced insulin resistance. Metformin has outstanding utility in reducing insulin resistance and preventing type-2-diabetes mellitus, but has not been studied for statin-associated muscle symptom rescue or prevention. The overlapping mechanisms of statin-associated muscle symptoms, statin-induced insulin resistance, and metformin intervention offers the potential to address two common and detrimental side effects of statins. As statins are the single best medication class for preventing cardiovascular events the potential for clinical benefit is large given metabolic syndrome's growing prevalence in the United States. Herein we hypothesize that metformin will rescue and prevent patients from statin-associated muscle symptoms. This hypothesis can benefit two patient groups: 1) patients at risk for diabetes who are taking a statin and experiencing muscle symptoms; and 2) patients with diabetes taking metformin who are to be started on a statin. Method to test Group 1) Symptom Rescue: randomized control trial of metformin versus placebo in patients with prediabetes who are already taking a statin, and are experiencing mild-to-moderate muscle symptoms. Method to test Group 2) Symptom Prevention: meta-analysis, of statin randomized control trials, with patient level data, comparing patients taking metformin at baseline to patients not taking metformin when a statin is started. An efficient method to simulate both symptom rescue and symptom prevention is a skeletal muscle cell culture model of statin-associated muscle symptom markers. These experiments would identify if metformin reverses (rescues) or prevents markers of statin-associated muscle symptoms. As metformin is recommended by the American Diabetes Association for type-2-diabetes mellitus prevention, yet not frequently used, validating this hypothesis will lead towards research and practice change including: a) decreases in the frequency of statin-associated muscle symptoms; leading to subsequent increases in statin therapy compliance; b) increases in metformin use in prediabetes with subsequent decrease in the incidence of type-2-diabetes mellitus; and c) decreases in complications of both cardiovascular disease and diabetes due to improved statin compliance and type-2-diabetes mellitus prevention.

Patients experiencing statin-induced myalgia exhibit a unique program of skeletal muscle gene expression following statin re-challenge

Statins, the 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase inhibitors, are widely prescribed for treatment of hypercholesterolemia. Although statins are generally well tolerated, up to ten percent of statin-treated patients experience myalgia symptoms, defined as muscle pain without elevated creatinine phosphokinase (CPK) levels. Myalgia is the most frequent reason for discontinuation of statin therapy. The mechanisms underlying statin myalgia are not clearly understood. To elucidate changes in gene expression associated with statin myalgia, we compared profiles of gene expression in skeletal muscle biopsies from patients with statin myalgia who were undergoing statin re-challenge (cases) versus those of statin-tolerant controls. A robust separation of case and control cohorts was revealed by Principal Component Analysis of differentially expressed genes (DEGs). To identify putative gene expression and metabolic pathways that may be perturbed in skeletal muscles of patients with statin myalgia, we subjected DEGs to Ingenuity Pathways (IPA) and DAVID (Database for Annotation, Visualization and Integrated Discovery) analyses. The most prominent pathways altered by statins included cellular stress, apoptosis, cell senescence and DNA repair (TP53, BARD1, Mre11 and RAD51); activation of pro-inflammatory immune response (CXCL12, CST5, POU2F1); protein catabolism, cholesterol biosynthesis, protein prenylation and RAS-GTPase activation (FDFT1, LSS, TP53, UBD, ATF2, H-ras). Based on these data we tentatively conclude that persistent myalgia in response to statins may emanate from cellular stress underpinned by mechanisms of post-inflammatory repair and regeneration. We also posit that this subset of individuals is genetically predisposed to eliciting altered statin metabolism and/or increased end-organ susceptibility that lead to a range of statin-induced myopathies. This mechanistic scenario is further bolstered by the discovery that a number of single nucleotide polymorphisms (e.g., SLCO1B1, SLCO2B1 and RYR2) associated with statin myalgia and myositis were observed with increased frequency among patients with statin myalgia.

Statin-Associated Side Effects

Hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins are well tolerated, but associated with various statin-associated symptoms (SAS), including statin-associated muscle symptoms (SAMS), diabetes mellitus (DM), and central nervous system complaints. These are "statin-associated symptoms" because they are rare in clinical trials, making their causative relationship to statins unclear. SAS are, nevertheless, important because they prompt dose reduction or discontinuation of these life-saving mediations. SAMS is the most frequent SAS, and mild myalgia may affect 5% to 10% of statin users. Clinically important muscle symptoms, including rhabdomyolysis and statin-induced necrotizing autoimmune myopathy (SINAM), are rare. Antibodies against HMG-CoA reductase apparently provoke SINAM. Good evidence links statins to DM, but evidence linking statins to other SAS is largely anecdotal. Management of SAS requires making the possible diagnosis, altering or discontinuing the statin treatment, and using alternative lipid-lowering therapy.

Statin-Associated Muscle Adverse Events: Update for clinicians

Statins are potent medications which reduce low-density lipoprotein cholesterol (LDL-C) levels. Their efficacy in cardiovascular risk reduction is well established and indications for their use are expanding. While statins are generally well tolerated and safe, adverse events are relatively common, particularly statin-associated muscle adverse events (SaMAEs), which are the most frequently encountered type of adverse event. Recent guidelines and guideline updates on SaMAEs and statin intolerance have included revised definitions of SaMAEs, incorporating new evidence on their pathogenesis and management. As SaMAEs emerge as a therapeutic challenge, it is important for physicians to be aware of updates on management strategies to ensure better patient outcomes. The majority of patients who are considered statin-intolerant can nevertheless tolerate some forms of statin therapy and successfully achieve optimal LDL-C levels. This review article discusses the recent classification of SaMAEs with emphasis on pathogenesis and management strategies.

A short-term statin treatment changes the contractile properties of fast-twitch skeletal muscles

Background

Cumulative evidence indicates that statins induce myotoxicity. However, the lack of understanding of how statins affect skeletal muscles at the structural, functional, and physiological levels hampers proper healthcare management. The purpose of the present study was to investigate the early after-effects of lovastatin on the slow-twitch soleus (Sol) and fast-twitch extensor digitorum longus (EDL) muscles.

Methods

Adult C57BL/6 mice were orally administrated with placebo or lovastatin [50 mg/kg/d] for 28 days. At the end of the treatment, the isometric ex vivo contractile properties of the Sol and EDL muscles were measured. Subtetanic and tetanic contractions were assessed and contraction kinetics were recorded. The muscles were then frozen for immunohistochemical analyses. Data were analyzed by two-way ANOVA followed by an a posteriori Tukey’s test.

Results

The short-term lovastatin treatment did not induce muscle mass loss, muscle fiber atrophy, or creatine kinase (CK) release. It had no functional impact on slow-twitch Sol muscles. However, subtetanic stimulations at 10 Hz provoked greater force production in fast-twitch EDL muscles. The treatment also decreased the maximal rate of force development (dP/dT) of twitch contractions and prolonged the half relaxation time (1/2RT) of tetanic contractions of EDL muscles.

Conclusions

An early short-term statin treatment induced subtle but significant changes in some parameters of the contractile profile of EDL muscles, providing new insights into the selective initiation of statin-induced myopathy in fast-twitch muscles.

A Peculiar Formula of Essential Amino Acids Prevents Rosuvastatin Myopathy in Mice

AIMS

Myopathy, characterized by mitochondrial oxidative stress, occurs in ∼10% of statin-treated patients, and a major risk exists with potent statins such as rosuvastatin (Rvs). We sought to determine whether a peculiar branched-chain amino acid-enriched mixture (BCAAem), found to improve mitochondrial function and reduce oxidative stress in muscle of middle-aged mice, was able to prevent Rvs myopathy.

RESULTS

Dietary supplementation of BCAAem was able to prevent the structural and functional alterations of muscle induced by Rvs in young mice. Rvs-increased plasma 3-methylhistidine (a marker of muscular protein degradation) was prevented by BCAAem. This was obtained without changes of Rvs ability to reduce cholesterol and triglyceride levels in blood. Rather, BCAAem promotes de novo protein synthesis and reduces proteolysis in cultured myotubes. Morphological alterations of C2C12 cells induced by statin were counteracted by amino acids, as were the Rvs-increased atrogin-1 mRNA and protein levels. Moreover, BCAAem maintained mitochondrial mass and density and citrate synthase activity in skeletal muscle of Rvs-treated mice beside oxygen consumption and ATP levels in C2C12 cells exposed to statin. Notably, BCAAem assisted Rvs to reduce oxidative stress and to increase the anti-reactive oxygen species (ROS) defense system in skeletal muscle. Innovation and Conclusions: The complex interplay between proteostasis and antioxidant properties may underlie the mechanism by which a specific amino acid formula preserves mitochondrial efficiency and muscle health in Rvs-treated mice. Strategies aimed at promoting protein balance and controlling mitochondrial ROS level may be used as therapeutics for the treatment of muscular diseases involving mitochondrial dysfunction, such as statin myopathy. Antioxid. Redox Signal. 25, 595-608.

Statin-associated myopathy and the quest for biomarkers: can we effectively predict statin-associated muscle symptoms?

Over the past three decades, statins have become the cornerstone of prevention and treatment of atherosclerotic cardiovascular and metabolic diseases. Albeit generally well tolerated, these drugs can elicit a variety of muscle-associated symptoms that represent the most important reason for treatment discontinuation. Statin-associated myopathy has been systematically underestimated by randomized controlled trials as compared with the incidence observed in clinical practice and obtained from patient registries. There are several reasons for this discrepancy, among which the lack of reliable diagnostic tests and a validated questionnaire to assess muscle symptoms are recognized as unmet needs. Here, we review the cellular and molecular mechanisms underlying statin-associated myopathy and discuss the experimental and clinical data on various biomarkers to diagnose and predict muscle-related complaints.

Laboratory Medicine in the Clinical Decision Support for Treatment of Hypercholesterolemia: Pharmacogenetics of Statins

Statin responsiveness is an area of great research interest given the success of the drug class in the treatment of hypercholesterolemia and in primary and secondary prevention of cardiovascular disease. Interrogation of the patient's genome for gene variants will eventually guide anti-hyperlipidemic intervention. In this review, we discuss methodological approaches to discover genetic markers predictive of class-wide and drug-specific statin efficacy and safety. Notable pharmacogenetic findings are summarized from hypothesis-free genome wide and hypothesis-led candidate gene association studies. Physiogenomic models and clinical decision support systems will be required for DNA-guided statin therapy to reach practical use in medicine.

Molecular mechanisms of statin intolerance

Statins reduce cardiovascular morbidity and mortality in primary and secondary prevention. Despite their efficacy, many persons are unable to tolerate statins due to adverse events such as hepatotoxicity and myalgia/myopathy. In the case of most patients, it seems that mild-to-moderate abnormalities in liver and muscle enzymes are not serious adverse effects and do not outweigh the benefits of coronary heart disease risk reduction. The risk for mortality or permanent organ damage ascribed to statin use is very small and limited to cases of myopathy and rhabdomyolysis. Statin-induced muscle-related adverse events comprise a highly heterogeneous clinical disorder with numerous, complex etiologies and a variety of genetic backgrounds. Every patient who presents with statin-related side effects cannot undergo the type of exhaustive molecular characterization that would include all of these mechanisms. Frequently the only solution is to either discontinue statin therapy/reduce the dose or attempt intermittent dosing strategies at a low dose.