Effect of SLCO1B1 T521C on Statin-Related Myotoxicity With Use of Lovastatin and Atorvastatin

Idebenone ameliorates statin-induced myotoxicity in atherosclerotic ApoE-/- mice by reducing oxidative stress and improving mitochondrial function

Statins are the first line of choice for the treatment for atherosclerosis, but their use can cause myotoxicity, a common side effect that may require dosage reduction or discontinuation. The exact mechanism of statin-induced myotoxicity is unknown. Previous research has demonstrated that the combination of idebenone and statin yielded superior anti-atherosclerotic outcomes. Here, we investigated the mechanism of statin-induced myotoxicity in atherosclerotic ApoE-/- mice and whether idebenone could counteract it. After administering simvastatin to ApoE-/- mice, we observed a reduction in plaque formation as well as a decrease in their exercise capacity. We observed elevated levels of lactic acid and creatine kinase, along with a reduction in the cross-sectional area of muscle fibers, an increased presence of ragged red fibers, heightened mitochondrial crista lysis, impaired mitochondrial complex activity, and decreased levels of CoQ9 and CoQ10. Two-photon fluorescence imaging revealed elevated H2O2 levels in the quadriceps, indicating increased oxidative stress. Proteomic analysis indicated that simvastatin inhibited the tricarboxylic acid cycle. Idebenone treatment not only further reduced plaque formation but also ameliorated the impaired exercise capacity caused by simvastatin. Our study represents the inaugural comprehensive investigation into the mechanisms underlying statin-induced myotoxicity. We have demonstrated that statins inhibit CoQ synthesis, impair mitochondrial complex functionality, and elevate oxidative stress, ultimately resulting in myotoxic effects. Furthermore, our research marks the pioneering identification of idebenone's capability to mitigate statin-induced myotoxicity by attenuating oxidative stress, thereby safeguarding mitochondrial complex functionality. The synergistic use of idebenone and statin not only enhances the effectiveness against atherosclerosis but also mitigates statin-induced myotoxicity.

Physiologically based pharmacokinetic (PBPK) modeling of pitavastatin in relation to SLCO1B1 genetic polymorphism

Pitavastatin, a potent 3-hydroxymethylglutaryl coenzyme A reductase inhibitor, is indicated for the treatment of hypercholesterolemia and mixed dyslipidemia. Hepatic uptake of pitavastatin is predominantly occupied by the organic anion transporting polypeptide 1B1 (OATP1B1) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene, which is a polymorphic gene that encodes OATP1B1. SLCO1B1 genetic polymorphism significantly alters the pharmacokinetics of pitavastatin. This study aimed to establish the physiologically based pharmacokinetic (PBPK) model to predict pitavastatin pharmacokinetics according to SLCO1B1 genetic polymorphism. PK-Sim® version 10.0 was used to establish the whole-body PBPK model of pitavastatin. Our pharmacogenomic data and a total of 27 clinical pharmacokinetic data with different dose administration and demographic properties were used to develop and validate the model, respectively. Physicochemical properties and disposition characteristics of pitavastatin were acquired from previously reported data or optimized to capture the plasma concentration-time profiles in different SLCO1B1 diplotypes. Model evaluation was performed by comparing the predicted pharmacokinetic parameters and profiles to the observed data. Predicted plasma concentration-time profiles were visually similar to the observed profiles in the non-genotyped populations and different SLCO1B1 diplotypes. All fold error values for AUC and Cmax were included in the two fold range of observed values. Thus, the PBPK model of pitavastatin in different SLCO1B1 diplotypes was properly established. The present study can be useful to individualize the dose administration strategy of pitavastatin in individuals with various ages, races, and SLCO1B1 diplotypes.

A gene risk score using missense variants in SLCO1B1 is associated with earlier onset statin intolerance

BACKGROUND AND AIMS

The efficacy of statin therapy is hindered by intolerance to the therapy, leading to discontinuation. Variants in SLCO1B1, which encodes the hepatic transporter OATB1B1, influence statin pharmacokinetics, resulting in altered plasma concentrations of the drug and its metabolites. Current pharmacogenetic guidelines require sequencing of the SLCO1B1 gene, which is more expensive and less accessible than genotyping. In this study, we aimed to develop an easy, clinically implementable functional gene risk score (GRS) of common variants in SLCO1B1 to identify patients at risk of statin intolerance.

METHODS AND RESULTS

A GRS was developed from four common variants in SLCO1B1. In statin users from Tayside, Scotland, UK, those with a high-risk GRS had increased odds across three phenotypes of statin intolerance [general statin intolerance (GSI): ORGSI 2.42; 95% confidence interval (CI): 1.29-4.31, P = 0.003; statin-related myopathy: ORSRM 2.51; 95% CI: 1.28-4.53, P = 0.004; statin-related suspected rhabdomyolysis: ORSRSR 2.85; 95% CI: 1.03-6.65, P = 0.02]. In contrast, using the Val174Ala genotype alone or the recommended OATP1B1 functional phenotypes produced weaker and less reliable results. A meta-analysis with results from adjudicated cases of statin-induced myopathy in the PREDICTION-ADR Consortium confirmed these findings (ORVal174Ala 1.99; 95% CI: 1.01-3.95, P = 0.048; ORGRS 1.76; 95% CI: 1.16-2.69, P = 0.008). For those requiring high-dose statin therapy, the high-risk GRS was more consistently associated with the time to onset of statin intolerance amongst the three phenotypes compared with Val174Ala (GSI: HRVal174Ala 2.49; 95% CI: 1.09-5.68, P = 0.03; HRGRS 2.44; 95% CI: 1.46-4.08, P < 0.001). Finally, sequence kernel association testing confirmed that rare variants in SLCO1B1 are associated with the risk of intolerance (P = 0.02).

CONCLUSION

We provide evidence that a GRS based on four common SLCO1B1 variants provides an easily implemented genetic tool that is more reliable than the current recommended practice in estimating the risk and predicting early-onset statin intolerance.

An Introductory Tutorial on Cardiovascular Pharmacogenetics for Healthcare Providers

Pharmacogenetics can improve clinical outcomes by reducing adverse drug effects and enhancing therapeutic efficacy for commonly used drugs that treat a wide range of cardiovascular diseases. One of the major barriers to the clinical implementation of cardiovascular pharmacogenetics is limited education on this field for current healthcare providers and students. The abundance of pharmacogenetic literature underscores its promise, but it can also be challenging to learn such a wealth of information. Moreover, current clinical recommendations for cardiovascular pharmacogenetics can be confusing because they are outdated, incomplete, or inconsistent. A myriad of misconceptions about the promise and feasibility of cardiovascular pharmacogenetics among healthcare providers also has halted clinical implementation. Therefore, the main goal of this tutorial is to provide introductory education on the use of cardiovascular pharmacogenetics in clinical practice. The target audience is any healthcare provider (or student) with patients that use or have indications for cardiovascular drugs. This tutorial is organized into the following 6 steps: (1) understand basic concepts in pharmacogenetics; (2) gain foundational knowledge of cardiovascular pharmacogenetics; (3) learn the different organizations that release cardiovascular pharmacogenetic guidelines and recommendations; (4) know the current cardiovascular drugs/drug classes to focus on clinically and the supporting evidence; (5) discuss an example patient case of cardiovascular pharmacogenetics; and (6) develop an appreciation for emerging areas in cardiovascular pharmacogenetics. Ultimately, improved education among healthcare providers on cardiovascular pharmacogenetics will lead to a greater understanding for its potential in improving outcomes for a leading cause of morbidity and mortality.

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.

Pharmacogenomics of lipid-lowering agents: the impact on efficacy and safety

Hyperlipidemia is a significant risk factor for cardiovascular disease morbidity and mortality. The lipid-lowering drugs are considered the cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease. Unfortunately, the lack of efficacy and associated adverse effects, ranging from mild-to-moderate to potentially life-threatening, lead to therapy discontinuation. Numerous reports support the role of gene polymorphisms in drugs' pharmacokinetic parameters and their associated adverse reactions. Therefore, this study aims to understand the pharmacogenomics of lipid-lowering drugs and the impact of genetic variants of key genes on the drugs' efficacy and toxicity. Indeed, genetically guided lipid-lowering therapy enhances overall safety, improves drug adherence and achieves long-term therapy.

Drug metabolism and drug transport of the 100 most prescribed oral drugs

Safe and effective use of drugs requires an understanding of metabolism and transport. We identified the 100 most prescribed drugs in six countries and conducted a literature search on in vitro data to assess contribution of Phase I and II enzymes and drug transporters to metabolism and transport. Eighty-nine of the 100 drugs undergo drug metabolism or are known substrates for drug transporters. Phase I enzymes are involved in metabolism of 67 drugs, while Phase II enzymes mediate metabolism of 18 drugs. CYP3A4/5 is the most important Phase I enzyme involved in metabolism of 43 drugs followed by CYP2D6 (23 drugs), CYP2C9 (23 drugs), CYP2C19 (22 drugs), CYP1A2 (14 drugs) and CYP2C8 (11 drugs). More than half of the drugs (54 drugs) are known substrates for drug transporters. P-glycoprotein (P-gp) is known to be involved in transport of 30 drugs, while breast cancer resistance protein (BCRP) facilitates transport of 11 drugs. A considerable proportion of drugs are subject to a combination of Phase I metabolism, Phase II metabolism and/or drug transport. We conclude that the majority of the most frequently prescribed drugs depend on drug metabolism or drug transport. Thus, understanding variability of drug metabolism and transport remains a priority.

l-Carnitine ameliorates the osteoporotic changes and protects against simvastatin induced myotoxicity and hepatotoxicity in glucocorticoid-induced osteoporosis in rats

The current study aimed to discover more effective drugs to treat osteoporosis (OP) with fewer side effects. OP was induced in 24 rats using dexamethasone (DEX) 7 mg/kg intramuscular once weekly for four weeks, with six rats as a negative control. The osteoporotic rats were divided into one untreated group (positive control) and three treated groups (n = 6) that received L-carnitine (L-Car) (100 mg/kg/d), simvastatin (SIMV) (10 mg/kg/d), and L-Car + SIMV in the same previous doses, all treatments were orally for four weeks. At the end of the experiment, serum calcium (Ca), phosphorous (P), alkaline phosphatase (ALP), osteoprotegerin (OPG), total antioxidant (TAO), creatine kinase (CK), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were measured. The femur was histopathologically examined. Serum Ca, OPG, and TAO levels increased significantly, while P and ALP levels decreased in the L-Car and SIMV treated groups compared to the DEX-treated group. Moreover, there was a significant decrease in CK, ALT, and AST levels in the L-Car and L-Car + SIMV treated groups compared to the DEX treated group. CONCLUSIONS: L-Car and SIMV have antiosteoporotic effects, as well as a synergistic effect. Moreover, L-Car ameliorates SIMV-induced myotoxicity and hepatoxicity.

Pharmacogenomic Study of Statin-Associated Muscle Symptoms in the ODYSSEY OUTCOMES Trial

Statin-associated muscle symptoms (SAMS) are the most frequently reported adverse events for statin therapies. Previous studies have reported an association between the p.Val174Ala missense variant in SLCO1B1 and SAMS in simvastatin-treated subjects; however, evidence for genetic predictors of SAMS in atorvastatin- or rosuvastatin-treated subjects is currently lacking.

A Cost-Consequence Analysis of Preemptive SLCO1B1 Testing for Statin Myopathy Risk Compared to Usual Care

There is a well-validated association between SLCO1B1 (rs4149056) and statin-associated muscle symptoms (SAMS). Preemptive SLCO1B1 pharmacogenetic (PGx) testing may diminish the incidence of SAMS by identifying individuals with increased genetic risk before statin initiation. Despite its potential clinical application, the cost implications of SLCO1B1 testing are largely unknown. We conducted a cost-consequence analysis of preemptive SLCO1B1 testing (PGx+) versus usual care (PGx-) among Veteran patients enrolled in the Integrating Pharmacogenetics in Clinical Care (I-PICC) Study. The assessment was conducted using a health system perspective and 12-month time horizon. Incremental costs of SLCO1B1 testing and downstream medical care were estimated using data from the U.S. Department of Veterans Affairs' Managerial Cost Accounting System. A decision analytic model was also developed to model 1-month cost and SAMS-related outcomes in a hypothetical cohort of 10,000 Veteran patients, where all patients were initiated on simvastatin. Over 12 months, 13.5% of PGx+ (26/193) and 11.2% of PGx- (24/215) participants in the I-PICC Study were prescribed Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline-concordant statins (Δ2.9%, 95% CI -4.0% to 10.0%). Differences in mean per-patient costs for lipid therapy prescriptions, including statins, for PGx+ compared to PGx- participants were not statistically significant (Δ USD 9.53, 95% CI -0.86 to 22.80 USD). Differences in per-patient costs attributable to the intervention, including PGx testing, lipid-lowering prescriptions, SAMS, laboratory and imaging expenses, and primary care and cardiology services, were also non-significant (Δ- USD 1004, 95% CI -2684 to 1009 USD). In the hypothetical cohort, SLCO1B1-informed statin therapy averted 109 myalgias and 3 myopathies at 1-month follow up. Fewer statin discontinuations (78 vs. 109) were also observed, but the SLCO1B1 testing strategy was 96 USD more costly per patient compared to no testing (124 vs. 28 USD). The implementation of SLCO1B1 testing resulted in small, non-significant increases in the proportion of patients receiving CPIC-concordant statin prescriptions within a real-world primary care context, diminished the incidence of SAMS, and reduced statin discontinuations in a hypothetical cohort of 10,000 patients. Despite these effects, SLCO1B1 testing administered as a standalone test did not result in lower per-patient health care costs at 1 month or over 1 year of treatment. The inclusion of SLCO1B1, among other well-validated pharmacogenes, into preemptive panel-based testing strategies may provide a better balance of clinical benefit and cost.