English

Abstract

With progressive vascular dysfunction, the endothelial cells mediate increased vessel tone by the synthesis and release of the vasoconstrictor substances primarily endothelin and endothelium-derived constricting factor(s), and by reduced elaboration of vasodilator products primarily nitric oxide. With this background, our study sought correlation of altered lipid profile; a cause of progressive vascular dysfunction, to the relative derangement of the two contrasting vascular biomarkers with respect to anthropometry in apparently healthy individuals. This was a case-control pilot study comprising of 30 overweight/obese healthy subjects (BMI >= 25 kg/m2 and/or WHR (female>0.85; male>1) and 30 non-obese healthy subjects (BMI< 25 kg/m2 and/or WHR (female<0.85; male<1) excluding all subjects with secondary cause of abnormal blood flow. Reactive hyperemia (RH) for indirect evaluation of nitric oxide levels was measured by impedance plethysmography (NICOMON, Larsen & Toubro) in the subject's forearm along with fasting plasma glucose, serum lipids and serum endothelin-1. A significant difference in blood flow index (BFI) at 1 min post-occlusion time (mean ± % SD) {control 1.81 ± 0.42 vs. study 1.60 ± 0.38} (P=0.041) was detected but RH, plasma glucose, lipid profile and serum endothelin were comparable in both the groups with lipid profile derangement present in either group, though not significant. So the two groups were clubbed to seek further association. Out of the two contrasting biomarkers, endothelin-1 and nitric oxide, only latter was significantly altered (raised) in subjects with deranged serum VLDL (P=0.026) and serum triglyceride (P=0.044). Therefore we concluded that altered lipid profile irrespective of measured anthropometric variables, affects the release of nitric oxide and it's like, before any detectable change in serum endothelin-1 levels. This in turn suggested the use of the former to predict the 'subclinical prelude' to 'manifest' metabolic disorder in such apparently healthy subjects and thus ensuring timely premorbid level care.