4.3 The V433M Variant of the CYP4F2 is Associated with Ischemic Stroke in Male Swedish Beyond its Effect on Blood Pressure

Introduction. The CYP4A11 and the CYP4F2 are responsible for renal production of 20- hydroxyeicosatetraenoic acid (20-HETE), a vasoconstrictor and natriuretic substance. The CYP4 A11 F434S and CYP4F2 V433M polymorphisms reduce 20-HETE production, in vitro.

Aim. To evaluate the effect of these polymorphisms on blood pressure (BP) levels, hypertension prevalence and risk of incident cardiovascular events in middle-aged Swedes.

Methods. The polymorphisms were genotyped in the cardiovascular cohort of the Malmö Diet and Cancer study. The incidence of cardiovascular events (coronary events, n= 276, and ischaemic stroke, n =199) was monitored over 10 years of follow-up. The analysis of BP levels was performed twice: either excluding or including subjects under antihypertensive treatment.

Results. In the whole population, CYP4 A11 S434S homozygotes had higher systolic BP, both crude and adjusted for number of antihypertensive drugs, and higher prevalence of hypertension respect to F434 carriers. Male, but not female, CYP4F2 M433 carriers had significantly higher crude and adjusted systolic and diastolic BP and a trend toward higher hypertension prevalence (p=0.06) with respect to V433V homozygotes. After adjustment for major cardiovascular risk factors, the hazard ratio (HR) for incident ischaemic stroke in male CYP4F2 M433 carriers was significantly higher with respect to V433V homozygotes (HR1.69; 95%C.I. 1.1–2.6) even when baseline BP levels and hypertension prevalence were included in the COX proportional-hazard model.

Conclusions. A common CYP4F2 V433M polymorphism might increase the risk of incident ischaemic stroke in males only partially through its elevating effect on BP. Further studies are needed to confirm these data.