Background: Impaired coronary flow reserve (CFR) can be used to indicate vascular dysfunction before the appearance of angiographic lesions. The hepatic lipase (HL) gene has a functional promoter polymorphism at position C-480T, which affects transcription and leads to high activity (C/C) and low activity (C/T, T/T) genotypes. These genotypes modulate HL activity, but their role in coronary artery disease is controversial and the effect on coronary function has not been studied. We investigated whether HL genotypes are associated with coronary artery function in healthy young men.
Materials and methods: We studied 49 healthy, mildly hypercholesterolemic men (aged 35 +/- 4 years). Myocardial blood flow was measured at rest and during adenosine induced hyperaemia with positron emission tomography using [15O] H2O. HL genotype was determined by PCR and Nla III enzyme digestion.
Results: Resting myocardial blood flow was not statistically different in subjects with high and low activity HL genotypes. However, CFR (the ratio of adenosine flow to resting flow) was 24% higher (4.62 +/- 1.52 vs. 3.73 +/- 1.08 mL g-1 min-1, P = 0.024) in men with the high activity genotype (n = 26) than in those with low activity (n = 23). In multivariate analysis, the HL genotype remained a significant predictor of CFR (P = 0.038) after adjusting for age, body mass index, serum lipids and smoking.
Conclusions: The findings of our preliminary study suggest that the C-480T polymorphism of the HL gene may modify coronary reactivity and reflect differences in the early pathogenesis of coronary dysfunction in these healthy young men. If the association between HL polymorphism and impaired CFR is also present in subjects with other dyslipoproteinemias, the HL polymorphism could be a new risk factor for cardiovascular disease.