Clopidogrel Response Variability: Impact of Genetic Polymorphism and Platelet Biomarkers for Predicting Adverse Outcomes Poststenting

Evaluation of Biomarkers in Critical Care and Perioperative Medicine: A Clinician’s Overview of Traditional Statistical Methods and Machine Learning Algorithms

Interest in developing and using novel biomarkers in critical care and perioperative medicine is increasing. Biomarkers studies are often presented with flaws in the statistical analysis that preclude them from providing a scientifically valid and clinically relevant message for clinicians. To improve scientific rigor, the proper application and reporting of traditional and emerging statistical methods (e.g., machine learning) of biomarker studies is required. This Readers' Toolbox article aims to be a starting point to nonexpert readers and investigators to understand traditional and emerging research methods to assess biomarkers in critical care and perioperative medicine.

Multi-Ethnic Analysis of Cardiac Pharmacogenetic Markers of Cytochrome P450 and Membrane Transporters Genes in the Russian Population

Aim. To summarize Russian studies using pharmacogenetic testing as applied to cardiology.Material and methods. The authors conducted an online search for articles in December 2018 using the following databases: PubMed, Google Scholar, eLIBRARY. The search was carried out by keywords: "Russia", "Russian", "cardiology" together with the terms associated with the polymorphic marker, including: «P450», «CYP2C19», «CYP2D6», «CYP2B1», «CYP2B6», «CYP2Е1», «CYP2C8», «CYP2C9», «CYP3A4», «CYP3A5», «CYP1A1», «CYP1A2», «CYP4F2», «CYP4F1», «ABCB1», «SLCO1B1», «VKORC1», «GGCX», «SULT1A1», «CULT1», «CES1», «gene», «genes», «pharmacogenetics», «pharmacogenomics», «ethnic group».Results. Generalization of information allowed to identify obscure genes that need to be investigated in pharmacogenetic studies. This information can be used for the development of dosing algorithms and the priority choice of drugs, considering the results of pharmacogenetic testing and planning future research.Conclusion. The results of the literature review indicate the importance of studying the most clinically valid and clinically useful pharmacogenetic markers (CYP2C19, CYP2C9, VKORC1, SLCO1B1) among various ethnic groups in the Russian Federation. With the accumulation of evidence of clinical validity and clinical utility of other pharmacogenetic markers (CES1, CYP2D6*4, etc.), the problem of interethnic differences in the carriage of clinically significant polymorphisms of these genes identified in previous studies in the Russian Federation increasingly requires attention. The most promising for the introduction into the clinical practice in the Russian Federation in the near future are polymorphic markers of the CYP2C19, CYP2C9, VKORC1 and SLCO1B1 genes.

ADME pharmacogenetics: future outlook for Russia

This systematic review reflects the results of pharmacogenetic studies in the Russian Federation aimed at studying the genes involved in the drug biotransformation system. The works of Russian researchers found by us are mostly devoted to microsomal liver oxidation enzymes (metabolism) and membrane transporter systems (absorption and excretion). This review presents population-ethnic and associative clinical studies on the genes of the CYP450 system, noncytochrome oxidation enzymes ( SULT1A1, CES1), membrane transporter system genes ( ABCB1, SLCO1B1) and warfarin biotransformation enzymes ( VKORC1, GGCX). The information is structured in the form of 11 tables, divided by regions of the Russian Federation.

PIK3CG single nucleotide polymorphisms are associated with poor responsiveness to clopidogrel and increased risk of ischemia in patients with coronary heart disease

BACKGROUND

This study explores the associations between PIK3CG single nucleotide polymorphisms (SNPs, rs1129293 and rs17398575) and patient responsiveness to clopidogrel to evaluate the risks of ischemia in patients with coronary heart disease (CHD).

METHODS

The study consisted of 513 CHD patients who received clopidogrel as part of antiplatelet therapy, after percutaneous coronary intervention. According to the patient responsiveness to clopidogrel, the subjects were assigned to either clopidogrel-resistant (CR) or clopidogrel-sensitive (CS) groups. CR group was determined by patients' platelet aggregation rate of ≥70% and poor responsiveness to clopidogrel, and CS group by patients' platelet aggregation rates of <70% and good responsiveness to clopidogrel. Polymerase chain reaction using TaqMan probe was employed to detect PIK3CG polymorphism. Haplotype and linkage disequilibrium analyses were performed. Prognosis analysis was performed using the Kaplan-Meier curve.

RESULTS

Significant difference was found in genotype and rs1129293 and rs17398575 allele frequency between the CR and CS groups. Haplotype analysis indicated that the frequency of TG allele was higher in the CR group compared with the CS group, and the frequency of CA allele was lower in the CR group compared with the CS group. Patients with rs1129293 CT + TT genotype and T allele, rs1129293 AG + GG genotype and G allele exhibited an increased CR risk. Logistic regression analysis determined hypertension history as an independent risk factor for CR. The Kaplan-Meier curve suggests that distribution curve of cumulative probability nonischemic events was different between patients with rs1129293 and rs17398575 alleles. Stable CHD patients with TT genotype of rs1129293 allele and GG genotype of rs17398575 allele showed poorer prognosis compared to those with other genotypes and patients with acute coronary syndromes.

CONCLUSION

A positive correlation may exist between PIK3CG SNPs (rs1129293 and rs17398575) and patients with poor responsiveness to clopidogrel. These findings show that this factor may contribute to an increased risk of ischemia in patients suffering from CHD.

Pharmacogenomics and pharmacogenetics for the intensive care unit: a narrative review

PURPOSE

Knowledge of how alterations in pharmacogenomics and pharmacogenetics may affect drug therapy in the intensive care unit (ICU) has received little study. We review the clinically relevant application of pharmacogenetics and pharmacogenomics to drugs and conditions encountered in the ICU.

SOURCE

We selected relevant literature to illustrate the important concepts contained within.

PRINCIPAL FINDINGS

Two main approaches have been used to identify genetic abnormalities - the candidate gene approach and the genome-wide approach. Genetic variability in response to drugs may occur as a result of alterations of drug-metabolizing (cytochrome P [CYP]) enzymes, receptors, and transport proteins leading to enhancement or delay in the therapeutic response. Of relevance to the ICU, genetic variation in CYP-450 isoenzymes results in altered effects of midazolam, fentanyl, morphine, codeine, phenytoin, clopidogrel, warfarin, carvedilol, metoprolol, HMG-CoA reductase inhibitors, calcineurin inhibitors, non-steroidal anti-inflammatory agents, proton pump inhibitors, and ondansetron. Changes in cholinesterase enzyme function may affect the disposition of succinylcholine, benzylisoquinoline muscle relaxants, remifentanil, and hydralazine. Genetic variation in transport proteins leads to differences in the response to opioids and clopidogrel. Polymorphisms in drug receptors result in altered effects of β-blockers, catecholamines, antipsychotic agents, and opioids. Genetic variation also contributes to the diversity and incidence of diseases and conditions such as sepsis, malignant hyperthermia, drug-induced hypersensitivity reactions, cardiac channelopathies, thromboembolic disease, and congestive heart failure.

CONCLUSION

Application of pharmacogenetics and pharmacogenomics has seen improvements in drug therapy. Ongoing study and incorporation of these concepts into clinical decision making in the ICU has the potential to affect patient outcomes.

Subclinical very late thrombus formation inside and outside the everolimus-eluting stent implanted 3 years prior in a patient with provoked coronary spasms

A 63-year-old man with non-ST-elevation acute myocardial infarction had undergone PROMUS Element stent implantation for stenosis with thrombus in the left main trunk and the proximal left anterior descending artery. A 6-month follow-up angiography revealed no restenosis or stent thrombosis, but severe provoked spasms in three vessels, for which medications were administered. Three years later, the patient experienced new-onset rest angina one morning. Optical coherence tomography revealed subclinical very late stent thromboses inside and outside the stent. The patients experienced a severe spasm. Platelet function was adequately reduced, and the cytochrome P450 2C19 genotype indicated an extensive metabolizer phenotype. The spasm may have caused the thromboses.