PPARA genetic variants increase the risk for cardiac pumping function reductions following acute high-altitude exposure: A self-controlled study

High-altitude Hypoxia Influences the Activities of the Drug-Metabolizing Enzyme CYP3A1 and the Pharmacokinetics of Four Cardiovascular System Drugs

(1) Background: High-altitude hypoxia has been shown to affect the pharmacokinetic properties of drugs. Although there is a high incidence of cardiovascular disease among individuals living in high-altitude areas, studies on the effect of high-altitude hypoxia on the pharmacokinetic properties of cardiovascular drugs are limited. (2) Methods: The aim of this study was to evaluate the pharmacokinetics of nifedipine, bosentan, simvastatin, sildenafil, and their respective main metabolites, dehydronifedipine, hydroxybosentan, simvastatin hydroxy acid, and N-desmethyl sildenafil, in rats exposed to high-altitude hypoxia. Additionally, the protein and mRNA expression of cytochrome P450 3A1 (CYP3A1), a drug-metabolizing enzyme, were examined. (3) Results: There were significant changes in the pharmacokinetic properties of the drugs in rats exposed to high-altitude hypoxia, as evidenced by an increase in the area under the curve (AUC) and the half-life (t_1/2z) and a decrease in total plasma clearance (CL_z/F). However, most of these changes were reversed when the rats returned to a normoxic environment. Additionally, there was a significant decrease in CYP3A1 expression in rats exposed to high-altitude hypoxia at both the protein and mRNA levels. (4) Conclusions: High-altitude hypoxia suppressed the metabolism of the drugs, indicating that the pharmacokinetics of the drugs should be re-examined, and the optimal dose should be reassessed in patients living in high-altitude areas.

PPARA genetic variants increase the risk for cardiac pumping function reductions following acute high-altitude exposure: A self-controlled study

Background

Left cardiac pumping function determines the compensatory capacity of the cardiovascular system following acute high‐altitude exposure. Variations in cardiac output (CO) at high altitude are inconsistent between individuals, and genetic susceptibility may play a crucial role. We sought to identify genetic causes of cardiac pumping function variations and describe the genotype–phenotype correlations.

Methods

A total of 151 young male volunteers were recruited and transferred to Lhasa (3,700 m) from Chengdu (<500 m) by plane. Genetic information related to hypoxic signaling and cardiovascular‐related pathways was collected before departure. Echocardiography was performed both before departure and 24 hr after arrival at high altitude.

Results

Here we reported that PPARA variants were closely related to high‐altitude cardiac function. The variants of rs6520015 C‐allele and rs7292407 A‐allele significantly increased the risk for cardiac pumping function reductions following acute high‐altitude exposure. In addition, the individuals carrying haplotypes in PPARA, namely, rs135538 C‐allele, rs4253623 A‐allele, rs6520015 C‐allele and rs7292407 A‐allele (C‐A‐C‐A), suffered a 7.27‐fold risk for cardiac pumping function reduction (95% CI: 2.39–22.15, p = .0006) compared with those carrying the wild‐type haplotype.

Conclusions

This self‐controlled study revealed that PPARA variations significantly increased the risk for cardiac pumping function reductions following acute high‐altitude exposure, providing a potential predictive marker before high‐altitude exposure and targets in mechanistic studies.