Human pharmacogenomic variation of antihypertensive drugs: from population genetics to personalized medicine

Replicated evidence for aminoacylase 3 and nephrin gene variations to predict antihypertensive drug responses

Aim: To replicate the genome-wide associations of the antihypertensive effects of bisoprolol and losartan in GENRES, using the Finnish patients of LIFE study. Patients & methods: We analyzed association of four SNPs with atenolol and three SNPs with losartan response in 927 Finnish LIFE patients (467 for atenolol and 460 for losartan). Results: rs2514036, a variation at a transcription start site of ACY3, was associated with blood pressure response to atenolol in men in LIFE. Response to bisoprolol was correlated to baseline plasma levels of N-acetylphenylalanine and phenylalanine (ACY3 substrate and end product, respectively) in GENRES study. NPHS1 variation rs3814995 was associated with losartan effect in LIFE. Conclusion: We provide support for two pharmacogenomic markers for beta-blockers and angiotensin receptor antagonists.

Pharmacogenomics considerations in the control of hypertension

The response to antihypertensive therapy is very heterogeneous and the need by the physicians to account for it has driven much interest in pharmacogenomics of antihypertensive drugs. The Human Genome Project and the initiatives in genomics that followed, generated a huge number of genetic data that furnished the tools to explore the genotype-phenotype association in candidate genes and at genome-wide level. In spite of the efforts and the great number of publications, pharmacogenomics of antihypertensive drugs is far from being used in clinical practice. In this review, we analyze the main findings available in PubMed from 2010 to 2015, in relation to the major classes of antihypertensive drugs. We also describe a new Phase II drug that targets two specific hypertension predisposing mechanisms.

Dissecting ancestry genomic background in substance dependence genome-wide association studies

AIMS

To understand the role of ancestral genomic background in substance dependence (SD) genome-wide association studies (GWAS), we analyzed population diversity at genetic loci associated with SD traits and evaluated its effect on GWAS outcomes.

MATERIALS & METHODS

We investigated 24 genes with variants associated with SD by GWAS; and 82 loci with putative subordinate roles with respect to SD-associated genes.

RESULTS

We observed high ancestry-related frequency differences in common functional alleles in GWAS relevant genes and their interactive partners. Common functional alleles with high frequency differences demonstrated significant effects on the GWAS outcomes.

CONCLUSION

Population differences in SD GWAS outcomes seem not to be influenced by general variation across the genome, but by ancestry-related local haplotype structures at SD-associated loci.

International warfarin genotype-guided dosing algorithms in the Turkish population and their preventive effects on major and life-threatening hemorrhagic events

AIM

To determine the accuracy of international warfarin pharmacogenetic algorithms developed on large multiethnic cohorts (comprising more than 1000 subjects) to predict therapeutic warfarin doses in Turkish patients.

MATERIALS & METHODS

We investigated two Turkish warfarin-treated cohorts: patients with no history of hemorrhagic or thromboembolic event and patients with major and life-threatening hemorrhagic events.

RESULTS

International pharmacogenetic algorithms showed good performances in predicting the therapeutic dose of patients with no history of bleedings, but they did not significantly detect the incorrect warfarin dose of patients with major and life-threatening hemorrhagic events.

CONCLUSION

Although genetic information can predict the therapeutic warfarin dose, the accuracy of the international pharmacogenetic algorithms is not sufficient to be used for warfarin screening in Turkish patients.

Explorative genetic association study of GSTT2B copy number variant in complex disease risks

BACKGROUND

Glutathione S-transferases (GSTs) are the main phase II enzymes involved in cellular detoxification. Through phase I and phase II detoxification reactions, the cell is able to detoxify endogenous and exogenous toxic compounds.

AIMS

This study focused attention on the GSTT2B copy number variant (CNV) in order to explore its involvement in the genetic pre-disposition to asthma, Alzheimer's disease (AD), allergic rhinitis (AR), essential hypertension (EH), hypothyroidism and recurrent miscarriage (RM).

METHODS

The study population consists of 1225 individuals divided into six case-control groups. The genotyping of the GSTT2B CNV was performed by using a duplex-PCR. Odds Ratios (ORs) were calculated, adjusting for the confounding variables, to estimate the association between GSTT2B CNV and the disease status.

RESULTS

The χ(2)-test and ORs did not show any association between this genetic marker and pathological phenotypes.

CONCLUSION

The data highlights that GSTT2B CNV is not associated with the investigated complex diseases in Italian patients. However, further investigations are necessary to replicate these findings in larger sample sizes and to explore other health-related phenotypes.

Personalized hypertension management in practice

The revolution occurring in genomic and personalized medicine is likely to have a significant impact on the management of hypertension. However, from the perspective of translating new knowledge into clinical practice, progress has been slow. This review article summarizes recent advances in hypertension-related diagnostics while also offering new perspective on hypertension management for the future. Such new perspectives will likely require a paradigm shift toward more integrated and holistic approaches for better prevention and treatment of hypertension in both individuals and the population as a whole.

Genetic diversity of disease-associated loci in Turkish population

Many consortia and international projects have investigated the human genetic variation of a large number of ethno-geographic groups. However, populations with peculiar genetic features, such as the Turkish population, are still absent in publically available datasets. To explore the genetic predisposition to health-related traits of the Turkish population, we analyzed 34 genes associated with different health-related traits (for example, lipid metabolism, cardio-vascular diseases, hormone metabolism, cellular detoxification, aging and energy metabolism). We observed relevant differences between the Turkish population and populations with non-European ancestries (that is, Africa and East Asia) in some of the investigated genes (that is, AGT, APOE, CYP1B1, GNB3, IL10, IL6, LIPC and PON1). As most complex traits are highly polygenic, we developed polygenic scores associated with different health-related traits to explore the genetic diversity of the Turkish population with respect to other human groups. This approach showed significant differences between the Turkish population and populations with non-European ancestries, as well as between Turkish and Northern European individuals. This last finding is in agreement with the genetic structure of European and Middle East populations, and may also agree with epidemiological evidences about the health disparities of Turkish communities in Northern European countries.