The C677T polymorphism of the methylenetetrahydrofolate reductase gene is associated with the level of decrease on diastolic blood pressure in essential hypertension patients treated by angiotensin-converting enzyme inhibitor

Abstract

Objectives: Elevated plasma homocysteine has been implicated as a risk factor for hypertension. C677T polymorphism in methylenetetrahydrofolate reductase gene ( MTHFR) is a major determinant of hyperhomocysteinemia, which results in endothelial dysfunction. Angiotensin-converting enzyme (ACE) inhibitors appear to remedy the endothelial dysfunction and restore endothelium-dependent vasodilatation. The co-existence of genetic polymorphisms in drug metabolizing enzymes, targets, receptors, and transporters may influence the drug efficacy. The purpose of this study was to investigate whether short-term blood pressure control by benazepril, an ACE inhibitor, was modulated by C677T MTHFR gene polymorphism. Methods and results: A total of 444 hypertensive patients, aged 27 to 65 years, without any anti hypertensive therapy within 2 weeks were included. All of them were treated orally with benazepril at a single daily fixed dosage of 10 mg for 15 consecutive days. Blood pressures were measured at baseline and on the 16th day of treatment. Among them, the frequency of MTHFR C677T genotype CC, CT and TT was 24.3%, 51.8%, and 23.9%, respectively. In a recessive model ( CC+ CT versus TT genotype), both baseline diastolic blood pressure (DBP) and diastolic blood pressure response (ΔDBP) were significantly higher in patients with the TT genotype than in those with the CT or CC genotype ( P value=0.0076 for DBP, and P value=0.0005 for ΔDBP). We further divided all patients into three groups based on the tertiles of the ΔBP distribution. Compared to subjects in the lowest tertile of ΔDBP, the adjusted relative odds of having the TT genotype among subjects in the highest tertile was 2.6 (95% CI, 1.4 to 4.9). However, baseline systolic blood pressure (SBP) and SBP response did not significantly associate with MTHFR C677T polymorphism. Conclusions: Our finding suggests that MTHFR C667T polymorphism modulated baseline DBP and DBP responsiveness by short-term treatment of ACE inhibitor in Chinese essential hypertensive patients.