Serum Apo AV Concentration In Patients With Coronary Artery Disease And Its Association With Triglyceride

BackgroundCoronary heart disease is the leading cause of mortality in both industrialized and developing countries. Hypertriglyceridemia which is part of dyslipidemia is an independent risk factor of coronary heart disease. Apolipoprotein AV (Apo AV) is a newly described member of the apolipoprotein gene family whose initial discovery arose from comparative sequence analysis of the mammalian Apo A1/C3/A4 gene cluster. Concentration of Apo AV in human plasma is within 114 to 258 ng/ml, very low when compared with other major HDL apolipoproteins such as Apo AI. Accumulating evidences showed that Apo AV was involved in the regulation of plasma triglyceride levels. Previous studies showed that human Apo AV transgenic mice had lower triglyceride levels than controls, whereas the knockouts had increased levels. Studies in humans have also demonstrated that polymorphisms and/or mutations in the Apo AV gene result in moderate to severe hypertriglyceridemia. However, recent studies conduct on both humans and mice with increased TG display a positive correlation between Apo AV and TG concentrations. Taken together, the relationship between levels of Apo AV and triglycerides levels is equivocal and the impact of Apo AV on plasma TG concentration is complex.ObjectiveThis study was designed to investigate the serum ApoAV concentration by ELISA in patients with coronary artery disease determined by angiography. The association of serum Apo AV and triglyceride was also examined.MethodsThree hundred and forty subjects underwent coronary angiography (CAG) were classified into CAD group (n=211) and non-CAD group (n=129) according to the CAG result. Serum ApoAV levels were determined by enzyme-linked immunosorbent assays. The severity of coronary artery stenosis was assessed by the numbers of involved coronary artery branches and the sum of the Gensini scores.ResultsSerum levels of Apo AV were significantly higher in coronary artery disease (CAD) group (192.0±114.6ng/ml) than in non coronary artery disease (non-CAD) group (164.4±107.5 ng/ml, p<0.05). Serum Apo AV was positively correlated (r= 0.229, P<0.01) with serum TG. Stratified analysis showed that the positive correlation was significant both in non coronary artery (non-CAD) disease group (r= 0.306, P<0.01) and the CAD group (r=0.172, p<0.05). Serum Apo AV was positively correlated with the Gensini score (r=0.182, P<0.01). The results showed Apo AV serum levels in G group 2(1-30) and G group 3(>30) were significantly higher than in G score 0 group. The Apo AV serum levels of G group 3 were higher than that of G group 2, but the difference did not reach statistical significance. However, after controlling the confounding factors by using multiple linear stepwise regression analysis, the correlation between Apo AV and Gensini scores disappeared. Using multivariate Logistic analysis with adjustment for confounding factors, the association between Apo AV levels and risk for future CAD also disappeared, (OR=1.214per 1 ng/ml,95% CI 0.942-1.564, P=0.134).Conclusions1. Serum Apo AV levels are positively correlated with TG levels.2. Serum Apo AV levels in coronary heart disease are significantly higher than in non-CAD group. Apo AV concentration is positively correlated to degree of coronary artery stenosis, but the correlation between Apo AV and CAD seems to be confounded by the effect of TG. We speculate that increase of Apo AV may be a consequence of compensation for the increased need for plasma TG hydrolysis.