APOE gene polymorphisms and response to statin therapy

Major Genetic Drivers of Statin Treatment Response in African Populations and Pharmacogenetics of Dyslipidemia Through a One Health Lens

A One Health lens is increasingly significant to address the intertwined challenges in planetary health concerned with the health of humans, nonhuman animals, plants, and ecosystems. A One Health approach can benefit the public health systems in Africa that are overburdened by noncommunicable, infectious, and environmental diseases. Notably, the COVID-19 pandemic revealed the previously overlooked two-fold importance of pharmacogenetics (PGx), for individually tailored treatment of noncommunicable diseases and environmental pathogens. For example, dyslipidemia, a common cardiometabolic risk factor, has been identified as an independent COVID-19 severity risk factor. Observational data suggest that patients with COVID-19 infection receiving lipid-lowering therapy may have better outcomes. However, among African patients, the response to these drugs varies from patient to patient, pointing to the possible contribution of genetic variation in important pharmacogenes. The PGx of lipid-lowering therapies may underlie differences in treatment responses observed among dyslipidemia patients as well as patients comorbid with COVID-19 and dyslipidemia. Genetic variations in APOE, ABCB1, CETP, CYP2C9, CYP3A4, CYP3A5, HMGCR, LDLR, NPC1L1, and SLCO1B1 genes affect the pharmacogenomics of statins, and they have individually been linked to differential responses to dyslipidemia and COVID-19 treatment. African populations are underrepresented in PGx research. This leads to poor accounting of additional diverse genetic variants that could be important in understanding interindividual and between-population variations in therapeutic responses to dyslipidemia and COVID-19. This expert review examines and synthesizes the salient and priority PGx variations, as seen through a One Health lens in Africa, to improve and inform personalized medicine in both dyslipidemia and COVID-19.

The Impact of the Apolipoprotein E Genotype on Cardiovascular Disease and Cognitive Disorders

Apolipoprotein E (ApoE) plays a critical role in cholesterol transport and protection against the development of atherosclerotic cardiovascular disease (ASCVD). Humans have 3 prevalent isoforms of ApoE: apolipoprotein E2 (ApoE2), apolipoprotein E3 (ApoE3), and apolipoprotein E4 (ApoE4). The E4 allele has been associated with higher ASCVD risk. While E4 patients do have higher cholesterol levels, they do not have enough to account for the substantially elevated ASCVD risk relative to E2 and E3 patients. ASCVD risk calculators would underestimate the true effect of E4 if the difference was caused entirely by a difference in cholesterol level. This article reviews the function of ApoE in atherosclerosis, and how each isoform functions differently. We review what is known about the molecular mechanisms through which ApoE prevents endothelial dysfunction and damage, how ApoE stimulates macrophage efflux of cholesterol from atherogenic lesions, and the ways in which ApoE decreases inflammation throughout atherosclerosis. The impact of ApoE on Alzheimer's disease and a discussion of why it is possibly unrelated to ASCVD prevention are included. Clinical applications to hyperlipidemia management and ASCVD prevention in specific patient populations are discussed.

Genetic Determinants of Response to Statins in Cardiovascular Diseases

Despite extensive efforts to identify patients with cardiovascular disease (CVD) who could most benefit from the treatment approach, patients vary in their benefit from therapy and propensity for adverse drug events. Genetic variability in individual responses to drugs (pharmacogenetics) is considered an essential determinant in responding to a drug. Thus, understanding these pharmacogenomic relationships has led to a substantial focus on mechanisms of disease and drug response. In turn, understanding the genomic and molecular bases of variables that might be involved in drug response is the main step in personalized medicine. There is a growing body of data evaluating drug-gene interactions in recent years, some of which have led to FDA recommendations and detection of markers to predict drug responses (e.g., genetic variant in VKORC1 and CYP2C9 genes for prediction of drug response in warfarin treatment). Also, statins are widely prescribed drugs for the prevention of CVD. Atorvastatin, fluvastatin, rosuvastatin, simvastatin, and lovastatin are the most common statins used to manage dyslipidemia. This review provides an overview of the current knowledge on the pharmacogenetics of statins, which are being used to treat cardiovascular diseases.

Statistical assessment of biomarker replicability using MAJAR method

In the era of precision medicine, many biomarkers have been discovered to be associated with drug efficacy and safety responses, which can be used for patient stratification and drug response prediction. Due to the small sample size and limited power of randomized clinical studies, meta-analysis is usually conducted to aggregate all available studies to maximize the power for identifying prognostic and predictive biomarkers. However, it is often challenging to find an independent study to replicate the discoveries from the meta-analysis (e.g. meta-analysis of pharmacogenomics genome-wide association studies (PGx GWAS)), which seriously limits the potential impacts of the discovered biomarkers. To overcome this challenge, we develop a novel statistical framework, MAJAR (meta-analysis of joint effect associations for biomarker replicability assessment), to jointly test prognostic and predictive effects and assess the replicability of identified biomarkers by implementing an enhanced expectation-maximization algorithm and calculating their posterior-probability-of-replicabilities and Bayesian false discovery rates (Fdr). Extensive simulation studies were conducted to compare the performance of MAJAR and existing methods in terms of Fdr, power, and computational efficiency. The simulation results showed improved statistical power with well-controlled Fdr of MAJAR over existing methods and robustness to outliers under different data generation processes. We further demonstrated the advantages of MAJAR over existing methods by applying MAJAR to the PGx GWAS summary statistics data from a large cardiovascular randomized clinical trial. Compared to testing main effects only, MAJAR identified 12 novel variants associated with the treatment-related low-density lipoprotein cholesterol reduction from baseline.

Polymorphisms of the apolipoprotein E gene affect response to atorvastatin therapy in acute ischemic stroke

Background

Polymorphisms of the apolipoprotein E (APOE) gene are related to the efficacy of statin therapy. The biological functions of the APOE subtypes determine the metabolism of blood plasma lipids and the progression of atherosclerosis. This study aimed to explore the impact of APOE gene polymorphisms on the effect of atorvastatin on lipid regulation and plaque stabilization.

Methods

The study was a prospective cohort study that consecutively included patients with acute ischemic stroke (AIS) in the Department of Neurology, Shanghai Tenth People's Hospital, from December 2018 to December 2019. The patients were divided into E2, E3, and E4 groups according to their APOE genotype. Atorvastatin (20 mg) was administrated to all patients. Changes in blood lipid levels over 3 months and plaque size and stability over 12 months were analyzed.

Results

We enrolled 253 consecutive patients with AIS, of whom, 136 had carotid atherosclerotic plaques. Two patients with genotype E2/E4 were excluded. There were 30 patients in the E2 group (12.0%), 191 patients in the E3 group (76.0%), and 30 patients in the E4 group (12.0%). The lowest percentage reduction in low-density lipoprotein cholesterol (LDL-C) was observed in the E4 group (41.2%), while the highest percentage reduction was observed in the E2 group (17.6%). The plaques in the E2 group showed slower progression, while those in the E4 group showed more rapid progression.

Conclusion

APOE gene polymorphisms affect the biological functions of atorvastatin. Compared to the ε3 or ε4 allele, the ε2 allele exerted a greater lipid-lowering effect on LDL-C levels, enhanced the ability of atorvastatin to stabilize carotid artery plaques, and slowed carotid artery plaque progression.

Hyperlipidemia patients carrying LDLR splicing mutation c.1187-2A>G respond favorably to rosuvastatin and PCSK9 inhibitor evolocumab

Mutations in the LDL receptor gene LDLR cause familial hypercholesterolemia (FH); however, the pharmacogenomics of specific LDLR mutations remains poorly understood. The goals of this study were to identify the genetic cause of a three-generation Chinese family affected with autosomal dominant FH, and to investigate the response of FH patients in the family to statin and evolocumab. Whole exome sequencing of the FH family with four patients and six unaffected members identified a heterozygous splicing mutation (c.1187-2A>G) in LDLR. The mutation co-segregated with FH in the family, providing strong genetic evidence to support its pathogenicity. The proband was a 48-year-old male FH patient who had an acute myocardial infarction (MI) and ventricular fibrillation (VF), and showed LDL-C of 5.23 mmol/L. A combination of life style modifications on food and exercise and treatment with rosuvastatin reduced his LDL-C to 2.05-2.80 mmol/L. Addition of ezetimibe did not improve rosuvastatin therapy, but addition of evolocumab further reduced LDL-C by 70% to 0.7 mmol/L at the first time and by 67% to 1.31 mmol/L at the second time. Rosuvastatin also reduced LDL-C for proband's father and sister by 40% and 43-63%, respectively. Lovastatin alone or addition to rosuvastatin treatment did not have any effect on LDL-C for the proband and his son. Both patients carry ApoE 3/4 genotype and SLCO1B1 rs4149056 TT genotype. These results suggest that combined treatment with rosuvastatin (but not lovastatin or ezetimibe) and evolocumab can control LDL-C to meet the LDL-C treatment goal for patients with LDLR splicing mutation c.1187-2A>G.

The SNPs rs429358 and rs7412 of APOE gene are association with cerebral infarction but not SNPs rs2306283 and rs4149056 of SLCO1B1 gene in southern Chinese Hakka population

Background

Apolipoprotein E (ApoE) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) regulate lipid metabolism. However, the relationship between genetic polymorphisms of APOE and SLCO1B1 and cerebral infarction (CI) remains unclear.

Methods

A total of 938 CI patients and 1028 control participants were included in the study. The rs429358 and rs7412 single nucleotide polymorphisms (SNPs) in the APOE gene and rs2306283 and rs4149056 SNPs in the SLCO1B1 gene were analyzed by fluorescence polymerase chain reaction (PCR).

Results

The genotype ɛ3/ɛ3 was the most common APOE genotype, with ɛ3 being the allele with the highest frequency, followed by ɛ4 and ɛ2. Statistically significant differences of genotype ɛ2/ɛ2 (χ² = 3.866, P = 0.049), ɛ2/ɛ3 (χ² = 20.030, P < 0.001), ɛ3/ɛ4 (χ² = 16.960, P < 0.001), and ɛ4/ɛ4 (χ² = 4.786, P = 0.029) between CI patients and controls were detected. The SLCO1B1 genotype *1b/*1b and haplotype *1b showed the highest frequency in the study sample. There was no statistically significant difference in the frequencies of SLCO1B1 genotypes and haplotypes among CI patients comparing with controls. Moreover, ε4 carriers had significantly higher low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (Apo-B) and lower apolipoprotein A1 (Apo-A1)/Apo-B levels than ε2 and ε3 carriers, but ε2 carriers showed lower LDL-C and Apo-B and higher Apo-A1/Apo-B than ε3 and ε4 carriers. Further, logistic regression analysis revealed that high LDL-C, high ApoB, smoking, hypertension and the ε4 allele were risks for the presence of CI.

Conclusions

This study indicated that the APOE SNPs rs429358 and rs7412 may be associated with susceptibility to cerebral infarction in southern Chinese Hakka population.

The Association between Apolipoprotein E Polymorphism and Response to Statins in Group of Hyperlipidemic Patients

BACKGROUND AND OBJECTIVE

APOE has an important role in lipids metabolism, and in the variability in low density lipoprotein (LDL) response to statins treatment between individuals. In this study, we aim to investigate the association between APOE polymorphism and response to statins in Jordanian hyperlipidemic patients at the diabetic clinic of Jordan University Hospital.

METHODS

One hundred and fifty two Jordanian Hyperlipidemic patients (52 males and 100 females) aged between 35-75 years were enrolled in this study. This study was approved by the Institutional Review Board (IRB) of Jordan University Hospital. The genotypes of the patients were identified by polymerase chain reaction followed by restriction fragment length polymorphism assay method (PCRRFLP).

RESULTS AND CONCLUSION

The study showed that there is an association between APOE polymorphism and response to statin therapy. Patients who were APOE ε4 carriers had lower response to statins compared to ε3 and ε2 carriers (p=0.002). In addition, we found that there was no significant association between APOE polymorphism and LDL baseline (p=0.214). No significant differences were found in APOE genotypes distribution between males and females (p=0.06). No significant association was found between age and APOE genotypes (p=0.347). A genotype screening test for dyslipidemic Jordanian patients is recommended to choose the appropriate treatment decisions, dosage, and to recognize the potential side effects of statin therapy.

Apolipoprotein E polymorphisms contribute to statin response in Chinese ASCVD patients with dyslipidemia

Background

Apolipoprotein E (ApoE) plays an important role in lipid metabolism and clearance. Statins are the most common drugs used to modulate the lipid profile in the clinic therapy; the associations between ApoE polymorphisms and statin response to lipids were inconsistent in previous studies among different ethnicities. Our study aimed to demonstrate the relationships among the statins response and the ApoE gene common polymorphisms and lifestyle risk factors in Chinese arteriosclerotic cardiovascular disease (ASCVD) patients with dyslipidemia.

Methods

A total of 1002 dyslipidemia ASCVD patients were recruited in this study, including 311 patients with a history of type 2 diabetes mellitus (T2DM). These patients were all treated with drugs atorvastatin (10 mg/d) or rosuvastatin (5 mg/d) for at least 4 weeks and genotyped for ApoE e2/e3/e4 alleles, using Kompetitive Allele Specific PCR (KASP) and Sanger sequencing. The plasma lipids levels were determined before and after statins treatment.

Results

The results of ApoE genotyping with KASP method were consistent with the sequencing analysis. In the total 1002 patients, the E2 phenotypes (e2/e3, e2/e2) had significant lower low-density lipoprotein cholesterol (LDL-C) baseline levels than subjects with E3 (e3/e3, e2/e4) and E4 (e3/e4, e4/e4) phenotypes (P = 0.007, 0.005, respectively), and E2 phenotypes had the highest triglyceride (TG) baseline levels. To statins treatment, E2 phenotypes had a better response in TG, Total cholesterol (TC) and LDL-C reduction percentage compared with other phenotypes, and smoking/alcohol drinking status also had a significant influence on statins response of LDL-C lowering. No significant difference was found in the effects of lipids decreasing between atorvastatin and rosuvastatin drugs in all patients.

Conclusions

We developed the KASP technique for the ApoE genotyping, and demonstrated ApoE polymorphisms interacted with smoking/drinking to influence the declining extent of TG, TC and LDL-C levels after statins therapy in Chinese dyslipidemia ASCVD patients. These discoveries developed our cognition with the genetic polymorphisms effects on statin response, which should be taken more seriously in smoking/drinking E4 amino acid isoform carriers.

Strength training attenuates post-infarct cardiac dysfunction and remodeling

Post-myocardial infarction (MI) exercise has been employed to improve cardiac function. However, most studies have focused on endurance training (Et). Although Et has been reported to preserve cardiac function, evidence suggests that Et increases left ventricle (LV) interior dimensions as a result of albumin-induced plasma expansion. In contrast, strength training (St) induces concentric cardiac hypertrophy and improved cardiac function without causing ventricular dilation. Therefore, the purpose of this study was to investigate the effects of St on cardiac function and remodeling in rats with MI. MI was surgically induced in 7-week-old rats via ligation of the coronary artery. Survivors were assigned to two experimental groups, MI-Sed (No exercise; n = 9), MI-St (St; n = 10), with a Sham group (no MI, no St; n = 9). MI-St rats began training 1-week post-MI by climbing a ladder with weights for 10 weeks. Echocardiographic measurements were performed prior to, and following exercise training, while in vivo LV hemodynamic analysis was conducted at the end of the experimental period. Our data revealed that St induced shortening of the LV end-diastolic dimension in the MI-St group compared with the MI-Sed group (P < 0.05). The peak velocities of contraction (+ dP/dt max) and relaxation (- dP/dt max) were significantly greater in the MI-St group than the MI-Sed group (P < 0.05). These training effects contributed to the improved fractional shortening (%FS). Our results demonstrate that St may be beneficial for post-MI by attenuating LV dilation and concomitant cardiac dysfunction associated with MI.

Effect of Low-Dose Statins and Apolipoprotein E Genotype on Cerebral Small Vessel Disease in Older Hypertensive Patients: A Subgroup Analysis of a Randomized Clinical Trial

OBJECTIVES

To investigate the effect of low-dose statins and apolipoprotein E (APOE) genotypes on cerebral small vessel disease (CSVD) to prevent CSVD in older hypertensive patients.

DESIGN

A subgroup analysis of a randomized clinical trial.

SETTING

Shandong area, China.

PARTICIPANTS

Hypertensive patients aged ≥60 years were recruited from April 2008 to November 2010.

MEASUREMENTS

Patients were randomly assigned to rosuvastatin (10 mg/day) or placebo groups. APOE genotypes were categorized as ε4 carriers and non-ε4 carriers. White matter hyperintensities (WMH), Fazekas scale, lacunes, and microbleeds were assessed.

RESULTS

After an average of intervention period of 61.8 months, WMH volume increased 1.45 ± 0.52 mL. There were 107 new-incident Fazekas scale ≥2, 65 new-incident lacunes, and 63 new-incident microbleeds. The increase in WMH volume was significantly lower in the rosuvastatin group than in the placebo group and was higher in APOE ε4 carriers than in non-ε4 carriers (all adjusted P < .001). The risk of new-incident Fazekas scale ≥2 was higher in the placebo group than in the rosuvastatin group (hazard ratio 2.150, 95% confidence interval 1.443-3.203; P < .001). APOE ε4 carriers were associated with an increased risk of new-incident Fazekas scale ≥2 compared with non-ε4 carriers (hazard ratio 1.973, 95% confidence interval 1.334-2.920; P = .001). There were no statistically significant differences in the risk of new-incident cerebral microbleeds between the rosuvastatin and placebo groups or between APOE ε4 carriers and non-ε4 carriers. There were no significant interactions between rosuvastatin use and APOE ε4 status regarding increased WMH volume (F = 1.020, P = .313) or for new-incident Fazekas scale ≥2 (P = .377), lacunes (P = .232), and microbleeds (P = .362).

CONCLUSIONS/IMPLICATIONS

Low-dose rosuvastatin is an effective and safe therapy for CSVD. The presence of APOE ε4 allele may not be able to predict rosuvastatin treatment outcomes for preventing and/or treating CSVD in older hypertensive patients.

Analysis of SLCO1B1 and APOE genetic polymorphisms in a large ethnic Hakka population in southern China

OBJECTIVE

Statins are the most widely used lipid-lowering drugs, which have a significant effect on the inhibition of cardiovascular disease. The efficacy and side effects of statins are associated with the polymorphisms of SLCO1B1 and APOE genes. The purpose of this study was to analyze the SLCO1B1 and APOE gene polymorphisms in the Hakka population of southern China.

METHODS

A total of 3249 subjects including 2019 males and 1230 females participated in this study. Polymerase chain reaction (PCR)-fluorescence probe technique for polymorphisms analysis and analyzed the genotypes frequencies of SLCO1B1 and APOE genes.

RESULTS

The frequencies of SLCO1B1 521T>C between men and women were statistically significant (SLCO1B1 521TT, χ2  = 8.431, P = .004; SLCO1B1 521TC, χ2  = 7.436, P = .007). The frequencies of haplotypes *1b/*1b (40.07%) and *1a/*1b (32.56%) of SLCO1B1 gene accounted for 72.63%, followed by *1b/*15(14.40%), *1a/*1a (5.82%), *1a/*15 (5.57%), *15/*15 (1.45%), and *1a/*5 (0.12%). The frequencies of haplotypes *1a/*15 and *1b/*1b of SLCO1B1 gene between men and women were statistically significant (*1a/*15, χ2  = 6.789, P = .009; *1b/*1b, χ2  = 3.998, P = .004). In this study, genotype ɛ3/ɛ3 accounted for 69.04%, followed by ɛ3/ɛ4 (16.19%), ɛ2/ɛ3 (11.60%), ɛ2/ɛ4 (1.35%), ɛ4/ɛ4 (1.08%), and ɛ2/ɛ2 (0.74%) in all subjects, in which ɛ3 had the greatest allele frequency (82.93%), followed by ɛ4 (9.85%) and ɛ2 (7.22%). We found that 47 subjects carrying the SLCO1B1 521 (CC) polymorphism who had not any myopathy caused by statins.

CONCLUSIONS

We analyzed the SLCO1B1 and APOE gene polymorphisms in the Hakka population of southern China. This study provides a reference for the individualized meditation for Hakka population in this area.

Ten-year progress of coronary artery lesions prior to Behçet disease diagnosis: A case report and care-compliant article

INTRODUCTION

Behçet disease is a multisystemic chronic inflammatory disorder characterized by recurrent oral aphthous ulcers, genital ulcers, uveitis, and skin lesions. However, particularly part of patients would present cardiovascular involvements and vascular lesions could be the presenting sign of Behçet disease preceding classical symptoms. We presented a middle aged male patient, in whom abdominal aorta pseudoaneurysm was as the first leading sign to reveal Behçet disease, and with his coronary artery lesions progress through a 10-year period before Behçet disease was diagnosed.

CONCLUSIONS

Coronary artery involvement of Behçet disease warrants more attention and investigation; repeated in-stent stenosis, aggressive progress, and elevated inflammation markers should be regard with more care earlier in clinical practice.

Pharmacogenetic Foundations of Therapeutic Efficacy and Adverse Events of Statins

Background: In the era of precision medicine, more attention is paid to the search for predictive markers of treatment efficacy and tolerability. Statins are one of the classes of drugs that could benefit from this approach because of their wide use and their incidence of adverse events. Methods: Literature from PubMed databases and bibliography from retrieved publications have been analyzed according to terms such as statins, pharmacogenetics, epigenetics, toxicity and drug–drug interaction, among others. The search was performed until 1 October 2016 for articles published in English language. Results: Several technical and methodological approaches have been adopted, including candidate gene and next generation sequencing (NGS) analyses, the latter being more robust and reliable. Among genes identified as possible predictive factors associated with statins toxicity, cytochrome P450 isoforms, transmembrane transporters and mitochondrial enzymes are the best characterized. Finally, the solute carrier organic anion transporter family member 1B1 (SLCO1B1) transporter seems to be the best target for future studies. Moreover, drug–drug interactions need to be considered for the best approach to personalized treatment. Conclusions: Pharmacogenetics of statins includes several possible genes and their polymorphisms, but muscular toxicities seem better related to SLCO1B1 variant alleles. Their analysis in the general population of patients taking statins could improve treatment adherence and efficacy; however, the cost–efficacy ratio should be carefully evaluated.

Atorvastatin Therapy Modulates Telomerase Activity in Patients Free of Atherosclerotic Cardiovascular Diseases

Background: Telomerase activity (TA) is considered as the biomarker for cardiovascular aging and cardiovascular diseases (CVDs). Recent studies suggest a link between statins and telomere biology that may be explained by anti-inflammatory actions of statins and their positive effect on TA. Until now, this effect has not been investigated in prospective randomized studies. We hypothesized that 12 months of atorvastatin therapy increased TA in peripheral blood mononuclear cells. Methods: In a randomized, placebo-controlled study 100 hypercholesterolemic patients, aged 35-75 years, free of known CVDs and diabetes mellitus type 2 received 20 mg of atorvastatin daily or placebo for 12 months. TA was measured by quantitative polymerase chain reaction. Results: At study end, 82 patients had sufficient peripheral blood mononuclear cells needed for longitudinal analysis. TA expressed as natural logarithms changed from 0.46 ± 0.05 to 0.68 ± 0.06 (p = 0.004) in the atorvastatin group and from 0.67 ± 0.06 to 0.60 ± 0.07 (p = 0.477) in the control group. In multiple regression analysis, atorvastatin therapy was the only independent predictor (p = 0.05) of the changes in TA independently of markers of chronic inflammation and oxidative stress. Atorvastatin therapy was associated with increases in interleukin-6 within the normal range and a tendency toward reduction in blood urea. Conclusion: These initial observations suggest atorvastatin can act as telomerase activator and potentially as effective geroprotector. Trial registration: The trial was registered in ISRCTN registry ISRCTN55050065.

Single-nucleotide polymorphisms: a perspective of cardiovascular prevention

INTRODUCTION

several studies have evaluated the utilization of lipid biomarkers in an attempt to correlate them with clinical cardiovascular events. Nevertheless, the investigation of clinical conditions under specific plasmatic levels of lipoproteins for long periods presents limitations due to inherent difficulties that are related to the follow-up of individuals throughout their lives. Better understanding of the clinical response and occasional resistance to the action of hypolipidemic drugs in several clinic scenarios is also necessary.

OBJECTIVES

to determine the role of evaluation of single-nucleotide polymorphisms (SNPs) related to the metabolism of lipids, and its implications in different clinical scenarios.

METHODS

a search of the literature in English and Spanish languages was performed in Medline, Lilacs via Bireme, IBECS via Bireme, and Cochrane databases. The expected results included information regarding plasmatic lipid profile and SNPs, cardiovascular clinical outcomes and polymorphisms related to the effectiveness of statins in the treatment of hypercholesterolemia.

RESULTS

in order to perform this analysis, 19 studies were included from a total of 89 identified citations. The evaluation of the results suggests that low plasmatic levels of LDL-c are associated with a reduction in the risk of heart attacks, although this was not observed for the rise of plasmatic levels of HDL-c.

CONCLUSION

polymorphisms in different populations and clinical perspectives may bring important contributions for a better understanding and adequacy of plasmatic lipoproteins aiming at reducing cardiovascular risk.

Biomarkers of cholesterol homeostasis in a clinical laboratory database sample comprising 667,718 patients

BACKGROUND

Circulating noncholesterol sterols/stanols (NCS) are used in clinical lipidology as surrogate measures of cholesterol synthesis and absorption, where they can be valuable tools in assessing cholesterol metabolism and personalizing therapies in patients with dyslipidemia.

OBJECTIVES

To describe the distributions of plasma NCS concentrations and inter-NCS correlations in a large cohort of American patients constituting a clinical laboratory database, and to investigate the relationship between circulating NCS, age, sex, and apolipoprotein E (APOE) genotype.

METHODS

A total of 667,718 patient blood samples submitted for testing to Health Diagnostic Laboratory, Inc. (Richmond, VA) were analyzed for cholesterol absorption markers (sitosterol, campesterol, and cholestanol) and one cholesterol synthesis marker (desmosterol). NCS percentiles were determined, along with intermarker correlations (Pearson's R). Analysis of variance was used to assess the effect of age and sex on NCS level, and to evaluate the relationship between cholesterol synthesis/absorption status and APOE genotype in a subset of 336,866 patients.

RESULTS

Mean NCS concentrations were: sitosterol, 2.45 μg/mL; campesterol, 3.3 μg/mL; cholestanol, 2.92 μg/mL; and desmosterol 0.99 μg/mL. The correlations between each NCS and its ratio to total cholesterol ranged from 0.72 (cholestanol) to 0.94 (desmosterol). NCS levels were significantly affected by age and sex (P < .0001), and prevalence of cholesterol hyperabsorption was higher in APOE ε4 allele carriers compared with the other APOE genotypes.

CONCLUSIONS

We have described sample distributions of NCS biomarkers and characterized their relationship to age, sex, and APOE genotype. These data may facilitate research into altered cholesterol homeostasis and human disease, and help physicians optimize lipid-lowering therapies.

ESR1 polymorphisms and statin therapy: a sex-specific approach

Lipid-lowering therapy has shown a high degree of variability in clinical response and there is evidence that the variability in drug response between individuals is due to genetic factors. Thirteen single nucleotide polymorphisms (SNPs) within the ESR1 gene were evaluated with basal lipid and lipoprotein levels, as well as response to lipid-lowering therapy, in 495 hypercholesterolemic individuals of European descent receiving simvastatin or atorvastatin. Significant associations were detected between rs4870061 (P=0.040, corrected P-value (PC)=0.440), rs1801132 (P=0.002, PC=0.022) and the SNP rs3020314 (P=0.013, PC=0.143) with triglyceride (TG) baseline levels. The rs4870061 was also associated with high-density lipoprotein cholesterol (HDL-C) baseline levels (P=0.045, PC=0.495). Regarding statin efficacy, rs2234693 C/C was associated with greater HDL-C increase (P=0.037; PC=0.407) and rs3798577 T allele was associated with greater total cholesterol (TC) reduction (P=0.019; PC=0.209) and greater TG reduction (P=0.026; PC=0.286). These associations suggest that ESR1 polymorphisms are in part responsible for the TC, HDL-C and TG variation levels and this effect may be sex-specific.

Pharmacogenomics of statin therapy: any new insights in efficacy or safety?

PURPOSE OF REVIEW

To examine the current evidence concerning the effects of genetic variation on statin-related low-density lipoprotein cholesterol reductions, clinical efficacy, and adverse events and the relevance for patient care.

RECENT FINDINGS

Recent years have seen the emergence of large-scale genetic experiments, including genome-wide association studies and candidate gene studies, exploring the impact of common genetic variation on patient response to statins. These studies have built on previous smaller scale evidence, providing improved statistical power and enhanced ability to explore the genome. Current evidence suggests that common genetic variants do not alter low-density lipoprotein cholesterol response by more than a few percent, or materially alter the effect of statin on vascular risk reduction, and therefore that patients benefit from statins independent of common genetic variation. However, knowledge of SLCO1B1 genotypes is believed to have clinical utility for predicting myopathy risk and ensuring that statins are prescribed as safely as possible. Furthermore, new hypothesis-generating studies, such as those associating GATM with myopathy risk, offer potential insights for the future.

SUMMARY

Common genetic variation does not appear to be an important determinant of statin response, with the exception of SLCO1B1 and risk of myopathy. Future studies will help to determine the impact of low-frequency and rare genetic variation on statin response.

Pharmacogenomics and cardiovascular disease

Variability in drug responsiveness is a sine qua non of modern therapeutics, and the contribution of genomic variation is increasingly recognized. Investigating the genomic basis for variable responses to cardiovascular therapies has been a model for pharmacogenomics in general and has established critical pathways and specific loci modulating therapeutic responses to commonly used drugs such as clopidogrel, warfarin, and statins. In addition, genomic approaches have defined mechanisms and genetic variants underlying important toxicities with these and other drugs. These findings have not only resulted in changes to the product labels but also have led to development of initial clinical guidelines that consider how to facilitate incorporating genetic information to the bedside. This review summarizes the state of knowledge in cardiovascular pharmacogenomics and considers how variants described to date might be deployed in clinical decision making.

Expanding role of pharmacogenomics in the management of cardiovascular disorders

Cardiovascular disease is a leading cause of death worldwide. Many pharmacologic therapies are available that aim to reduce the risk of cardiovascular disease but there is significant inter-individual variation in drug response, including both efficacy and toxicity. Pharmacogenetics aims to personalize medication choice and dosage to ensure that maximum clinical benefit is achieved whilst side effects are minimized. Over the past decade, our knowledge of pharmacogenetics in cardiovascular therapies has increased significantly. The anticoagulant warfarin represents the most advanced application of pharmacogenetics in cardiovascular medicine. Prospective randomized clinical trials are currently underway utilizing dosing algorithms that incorporate genetic polymorphisms in cytochrome P450 (CYP)2C9 and vitamin k epoxide reductase (VKORC1) to determine warfarin dosages. Polymorphisms in CYP2C9 and VKORC1 account for approximately 40 % of the variance in warfarin dose. There is currently significant controversy with regards to pharmacogenetic testing in anti-platelet therapy. Inhibition of platelet aggregation by aspirin in vitro has been associated with polymorphisms in the cyclo-oxygenase (COX)-1 gene. However, COX-1 polymorphisms did not affect clinical outcomes in patients prescribed aspirin therapy. Similarly, CYP2C19 polymorphisms have been associated with clopidogrel resistance in vitro, and have shown an association with stent thrombosis, but not with other cardiovascular outcomes in a consistent manner. Response to statins has been associated with polymorphisms in the cholesterol ester transfer protein (CETP), apolipoprotein E (APOE), 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, calmin (CLMN) and apolipoprotein-CI (APOC1) genes. Although these genes contribute to the variation in lipid levels during statin therapy, their effects on cardiovascular outcomes requires further investigation. Polymorphisms in the solute carrier organic anion transporter 1B1 (SLCO1B1) gene is associated with increased statin exposure and simvastatin-induced myopathy. Angiotensin-converting enzyme (ACE) inhibitors and β-adrenoceptor antagonists (β-blockers) are medications that are important in the management of hypertension and heart failure. Insertion and deletion polymorphisms in the ACE gene are associated with elevated and reduced serum levels of ACE, respectively. No significant association was reported between the polymorphism and blood pressure reduction in patients treated with perindopril. However, a pharmacogenetic score incorporating single nucleotide polymorphisms (SNPs) in the bradykinin type 1 receptor gene and angiotensin-II type I receptor gene predicted those most likely to benefit and suffer harm from perindopril therapy. Pharmacogenetic studies into β-blocker therapy have focused on variations in the β1-adrenoceptor gene and CYP2D6, but results have been inconsistent. Pharmacogenetic testing for ACE inhibitor and β-blocker therapy is not currently used in clinical practice. Despite extensive research, no pharmacogenetic tests are currently in clinical practice for cardiovascular medicines. Much of the research remains in the discovery phase, with researchers struggling to demonstrate clinical utility and validity. This is a problem seen in many areas of therapeutics and is because of many factors, including poor study design, inadequate sample sizes, lack of replication, and heterogeneity amongst patient populations and phenotypes. In order to progress pharmacogenetics in cardiovascular therapies, researchers need to utilize next-generation sequencing technologies, develop clear phenotype definitions and engage in multi-center collaborations, not only to obtain larger sample sizes but to replicate associations and confirm results across different ethnic groups.

Clinical delivery of pharmacogenetic testing services: a proposed partnership between genetic counselors and pharmacists

One of the basic questions in the early uses of pharmacogenetic (PGx) testing revolves around the clinical delivery of testing. Because multiple health professionals may play a role in the delivery of PGx testing, various clinical delivery models have begun to be studied. We propose that a partnership between genetic counselors and pharmacists can assist clinicians in the delivery of comprehensive PGx services. Based on their expert knowledge of pharmacokinetics and pharmacodynamics, pharmacists can facilitate the appropriate application of PGx test results to adjust medication use as warranted and act as a liaison to the healthcare team recommending changes in medication based on test results and patient input. Genetic counselors are well-trained in genetics as well as risk communication and counseling methodology, but have limited knowledge of pharmaceuticals. The complementary knowledge and skill set supports the partnership between genetic counselors and pharmacists to provide effective PGx testing services.

Pharmacogenetics of statins: achievements, whole-genome analyses and future perspectives

Statins are the most commonly prescribed class of drug worldwide and therapy is highly effective in reducing low-density lipoprotein cholesterol levels and cardiovascular events. However, there is large variability in clinical response to statin treatment. Recent research provides evidence that genetic variation contributes to this variable response to statin treatment. Until recently, pharmacogenetic studies have used mainly candidate gene approaches to investigate these effects. Since candidate gene studies explain only a small part of the observed variation and results have often been inconsistent, genome-wide association (GWA) studies may be a better approach. In this paper the most important candidate gene studies and the first published GWA studies assessing statin response are discussed. Moreover, we describe the PHASE study, an EU-funded GWA study that will investigate the genetic variation responsible for the variation in response to pravastatin in a large randomized clinical trial.

Impact of common genetic variation on response to simvastatin therapy among 18 705 participants in the Heart Protection Study

Aims

Statins reduce LDL cholesterol (LDL-C) and the risk of vascular events, but it remains uncertain whether there is clinically relevant genetic variation in their efficacy. This study of 18 705 individuals aims to identify genetic variants related to the lipid response to simvastatin and assess their impact on vascular risk response.

Methods and results

A genome-wide study of the LDL-C and apolipoprotein B (ApoB) response to 40 mg simvastatin daily was performed in 3895 participants in the Heart Protection Study, and the nine strongest associations were tested in 14 810 additional participants. Selected candidate genes were also tested in up to 18 705 individuals. There was 90% power to detect differences of 2.5% in LDL-C response (e.g. 42.5 vs. 40% reduction) in the genome-wide study and of 1% in the candidate gene study. None of the associations from the genome-wide study was replicated, and nor were significant associations found for 26 of 36 candidates tested. Novel lipid response associations with variants in LPA, CELSR2/PSRC1/SORT1, and ABCC2 were found, as well as confirmatory evidence for published associations in LPA, APOE, and SLCO1B1. The largest and most significant effects were with LPA and APOE, but were only 2–3% per allele. Reductions in the risk of major vascular events during 5 years of statin therapy among 18 705 high-risk patients did not differ significantly across genotypes associated with the lipid response.

Conclusions

Common genetic variants do not appear to alter the lipid response to statin therapy by more than a few per cent, and there were similar large reductions in vascular risk with simvastatin irrespective of genotypes associated with the lipid response to simvastatin. Consequently, their value for informing clinical decisions related to maximizing statin efficacy appears to be limited.

Pharmacogenomics of adverse drug reactions: implementing personalized medicine

Pharmacogenomics aims to investigate the genetic basis of inter-individual differences in drug responses, such as efficacy, dose requirements and adverse events. Research in pharmacogenomics has grown over the past decade, evolving from a candidate-gene approach to genome-wide association studies (GWASs). Genetic variants in genes coding for drug metabolism, drug transport and more recently human-leukocyte antigens (HLAs) have been linked to inter-individual differences in the risk of adverse drug reactions (ADRs). The tight association of specific HLA alleles with Stevens-Johnson syndrome, toxic epidermal necrolysis, drug hypersensitivity syndrome and drug-induced liver injury underscore the importance of HLA in the pathogenesis of these idiosyncratic drug hypersensitivity reactions. However, as with the search for the genetic basis for common diseases, pharmacogenomic research, including GWAS, has so far been a disappointment in discovering major gene variants responsible for the efficacy of drugs used to treat common diseases. This review focuses on the pharmacogenomics of ADRs, the underlying mechanisms and the potential use of genomic biomarkers in clinical practice for dose adjustment and the avoidance of drug toxicity. We also discuss obstacles to the implementation of pharmacogenomics and the direction of future translational research.

Effect of apolipoprotein E polymorphism on statin-induced decreases in plasma lipids and cardiovascular events

Hypercholesterolemia or dyslipidemia is an independent risk factor for cardiovascular disease and statins (inhibitors of a key enzyme of cholesterol synthesis, 3-hydroxymethyl glutaryl coenzyme A reductase) are the drugs of choice for decreasing plasma cholesterol. It has been estimated that genetic factors can explain 40%-60% of final cholesterol concentrations and approximately 70% of the efficacy of statin treatment. The gene most often analyzed in the context of statin efficacy is the gene for apolipoprotein E (APOE). This review summarizes evidence of the association between variations in the APOE gene locus and the response of plasma lipids to statin therapy. Although the results are not consistent, carriers of the APOE4 allele seems to be less responsive to statins than carriers of APOE2 and APOE3 alleles. This effect is partially context-dependent (gene-gender interactions; gene-nutrition and gene-smoking interactions have not yet been studied) and the absolute differences vary between different population groups.

Statins personalized

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitor medications, commonly referred to as statins, are among the most widely prescribed medications. Variation in individual response to statins concerning low-density lipoprotein cholesterol reduction, clinical event benefit, and side effects has been observed. Some of this variability is attributed to demographic and environmental issues, chief of which is compliance. A large portion of the individual response to statin therapy is attributed to single nucleotide polymorphisms that have recently been elucidated, several of which seem to have clinical utility.

Apolipoprotein E mRNA expression in mononuclear cells from normolipidemic and hypercholesterolemic individuals treated with atorvastatin

Background

Apolipoprotein E (apoE) is a key component of the lipid metabolism. Polymorphisms at the apoE gene (APOE) have been associated with cardiovascular disease, lipid levels and lipid-lowering response to statins. We evaluated the effects on APOE expression of hypercholesterolemia, APOE ε2/ε3/ε4 genotypes and atorvastatin treatment in Brazilian individuals. The relationship of APOE genotypes and plasma lipids and atorvastatin response was also tested in this population.

Methods

APOE ε2/ε3/ε4 and plasma lipids were evaluated in 181 normolipidemic (NL) and 181 hypercholesterolemic (HC) subjects. HC individuals with indication for lowering-cholesterol treatment (n = 141) were treated with atorvastatin (10 mg/day/4-weeks). APOE genotypes and APOE mRNA in peripheral blood mononuclear cells (PBMC) were analyzed by TaqMan real time PCR.

Results

HC had lower APOE expression than NL group (p < 0.05) and individuals with low APOE expression showed higher plasma total and LDL cholesterol and apoB, as well as higher apoAI (p < 0.05). Individuals carrying ε2 allele have reduced risk for hypercholesterolemia (OR: 0.27, 95% I.C.: 0.08-0.85, p < 0.05) and NL ε2 carriers had lower total and LDL cholesterol and apoB levels, and higher HDL cholesterol than non-carriers (p < 0.05). APOE genotypes did not affect APOE expression and atorvastatin response. Atorvastatin treatment do not modify APOE expression, however those individuals without LDL cholesterol goal achievement after atorvastatin treatment according to the IV Brazilian Guidelines for Dyslipidemia and Atherosclerosis Prevention had lower APOE expression than patients with desirable response after the treatment (p < 0.05).

Conclusions

APOE expression in PBMC is modulated by hypercholesterolemia and the APOE mRNA level regulates the plasma lipid profile. Moreover the expression profile is not modulated neither by atorvastatin nor APOE genotypes. In our population, APOE ε2 allele confers protection against hypercholesterolemia and a less atherogenic lipid profile. Moreover, low APOE expression after treatment of patients with poor response suggests a possible role of APOE level in atorvastatin response.

Genetic testing for early detection of individuals at risk of coronary heart disease and monitoring response to therapy: challenges and promises

Coronary heart disease (CHD) often presents suddenly with little warning. Traditional risk factors are inadequate to identify the asymptomatic high-risk individuals. Early identification of patients with subclinical coronary artery disease using noninvasive imaging modalities would allow the early adoption of aggressive preventative interventions. Currently, it is impractical to screen the entire population with noninvasive coronary imaging tools. The use of relatively simple and inexpensive genetic markers of increased CHD risk can identify a population subgroup in which benefit of atherosclerotic imaging modalities would be increased despite nominal cost and radiation exposure. Additionally, genetic markers are fixed and need only be measured once in a patient's lifetime, can help guide therapy selection, and may be of utility in family counseling.

A systematic review on pharmacogenetics in cardiovascular disease: is it ready for clinical application?

Pharmacogenetics is the search for heritable genetic polymorphisms that influence responses to drug therapy. The most important application of pharmacogenetics is to guide choosing agents with the greatest potential of efficacy and smallest risk of adverse drug reactions. Many studies focusing on drug-gene interactions have been published in recent years, some of which led to adaptation of FDA recommendations, indicating that we are on the verge of the clinical application of genetic information in drug therapy. This systematic review provides a comprehensive overview of the current knowledge on pharmacogenetics of all major drug classes currently used in the treatment of cardiovascular diseases.

ApoE polymorphism may determine low-density lipoprotein cholesterol level in association with obesity and metabolic syndrome in postmenopausal Korean women

PURPOSE

We investigated how serum low-density lipoprotein (LDL) level is related to various isoforms of apolipoprotein (ApoE) polymorphism in association with obesity and metabolic syndrome.

MATERIALS AND METHODS

We gathered total 332 sample of postmenopausal Korean women and analyzed ApoE isoforms, serum lipid level including LDL, blood pressure, fasting glucose, and anthropometry. The relationship between ApoE isoforms and serum lipid level, metabolic syndrome, and obesity was investigated.

RESULTS

Six ApoE isoforms were found, ApoE2 [E2/2 (n=1), E2/3 (n=54), E2/4 (n=14)], ApoE3 (E3/3, n=200), ApoE4 [E3/4 (n=55), and E4/4 (n=8)]. The prevalence of metabolic syndrome and obesity showed higher ApoE3 isoform than that of other isoforms. In additon, ApoE3 isoform was related to higher serum LDL and total cholesterol level than to ApoE2 isoform. The odds ratio of having the highest LDL cholesterol quartile in ApoE3 with obesity, compared to ApoE2 without obesity, was 3.46 [95% confidence interval (CI); 1.07-11.14, p=0.037], and odds ratio of ApoE3 with metabolic syndrome compared to ApoE2 without metabolic syndrome was 5.06 (95% CI; 1.14-22.29, p=0.037). Serum LDL cholesterol was positively associated with obesity or metabolic syndrome in ApoE3 isoform.

CONCLUSION

This study suggests that obesity or metabolic syndrome risk should be effectively managed in ApoE3 isomform groups to reduce serum LDL in postmenopausal Korean women.

The ABCG2 transporter and its relations with the pharmacokinetics, drug interaction and lipid-lowering effects of statins

IMPORTANCE OF THE FIELD

The ABCG2 efflux transporter is expressed in multiple tissues and plays an important role in the disposition of many statins. The functional 421C>A polymorphism in ABCG2 that reduces transporter activity has been found to be associated with increased systemic exposures to certain statins.

AREAS COVERED IN THIS REVIEW

We review and evaluate the associations of the ABCG2 polymorphism on the pharmacokinetics and clinical efficacy of statins.

WHAT THE READER WILL GAIN

This article gives a detailed overview of the ABCG2 transporter and extensively reviews its relations with the pharmacokinetics and lipid-lowering effects of statins. This review also discusses the potential role of the ABCG2 polymorphism in the clinical outcomes in statin-treated patients and statin-drug interactions.

TAKE HOME MESSAGE

The impact of the ABCG2 421C>A polymorphism on the disposition of the statins varies between different drugs and the effect on systemic exposure was greater in the case of rosuvastatin than other statins. This genetic variant was associated with greater low-density lipoprotein cholesterol response to rosuvastatin in Chinese and caucasian patients. The effect of the ABCG2 421C>A polymorphism on the lipid response to other substrate statins and clinical outcomes need to be evaluated in future studies.

Polymorphisms and haplotypes in TLR9 and MYD88 are associated with the development of Hodgkin's lymphoma: a candidate-gene association study

Toll-like receptors (TLRs) and myeloid differentiation primary response protein 88 (MYD88) gene polymorphisms may be involved in the pathogenesis of Hodgkin's lymphoma (HL) through altered immunoregulatory and inflammatory responses. A candidate-gene association study was conducted to investigate the association between TLR9 -1237T>C, TLR9 2848A>G, MYD88 -938C>A and MYD88 1944C>G gene polymorphisms and the risk for HL. The impact of haplotypes was also examined. The study showed that carriership for -1237C and 2848A was associated with an increased risk for HL (odds ratio (OR)=2.53 (1.36-4.71) and OR=6.20 (1.3-28.8)). The MYD88 polymorphisms produced nonsignificant results. The estimated frequencies of the TLR9/1237C-2848A and MYD88/938C-1944G haplotypes were also significantly different between HL and controls (P<0.01). In addition, a significant difference between HL and controls was observed for the TLR9/1237C-TLR9/2848A-MYD88/938C-MYD88/1944C haplotypes (P<0.01). In conclusion, our study showed that TLR polymorphisms, and TLR9 and MYD88 haplotypes are related to the development of HL.