Priyanka S. Bannikoppa ¹, Sheila Uthappa ², Anura V. Kurpad ¹, Indu Mani ¹

Affiliations
1 Division of Nutrition, St. John’s Research Institute, St. John’s Medical College, Bangalore, IN
2 Department of Biochemistry, St. John’s Medical College, Bangalore, IN

Abstract

Metabolic Syndrome (MS) is a combination of physiological factors that result in increased risk for developing Cardio Vascular Diseases (CVD). One factor that has traditionally been accepted as being athero-protective is High Density Lipoprotein (HDL). However increasing reports suggest that plasma levels of HDL-C do not reflect its functionality, which is mainly attributed to its cargo of antioxidant enzymes. The study was aimed at assessing key HDL-associated enzymes as potentially better biomarkers in evaluating risk of MS and thus CVD than merely HDL-C levels in an urban South Indian population. The study consisted of patients with MS (n=41) and age matched controls (n=65). Anthropometry, routine blood biochemistry and HDL associated enzyme activities were measured. Of the HDL enzymes, paraoxonase-1 (PON-1) activity was seen to be lower whereas Lecithin Cholesterol Acyl Transferase (LCAT) was higher in subjects with MS (p<0.01). Multiple logistic regression showed that low PON-1 activity and high LCAT activity had an increased AOR for MS (RR=3.8, 95% CI-1.1, 13.3, p=0.035, and RR=17.5, 95% CI-3.9, 77.5, p<0.001 respectively), independent of HDL-C levels. This study demonstrates the prevalence of impaired function of HDL enzymes in patients with MS, which might promote inflammation, oxidative stress and atherogenesis. It also suggests that estimating the activities of key HDL enzymes such as PON-1 and LCAT could improve the accuracy of MS and CVD risk prediction than mere measurement of HDL-C levels.

Keywords

CVD, HDL-C, Inflammation, LCAT, Metabolic Syndrome, PON-1.

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Priyanka S. Bannikoppa ¹, Sheila Uthappa ², Tinku Thomas ¹, Anura V. Kurpad ¹, Indu Mani ¹

Affiliations
1 Division of Nutrition, St John’s Research Institute, Bangalore, IN
2 Department of Biochemistry, St. John’s Medical College and Hospital, Bangalore, IN

Abstract

High Density Lipoprotein (HDL) is considered to be an anti-atherogenic molecule and its beneficial function is driven by a number of enzymes such as LCAT (Lecithin Cholesterol Acyl Transferase), PON1 (Paraoxonase 1), PAF-AH (Platelet-Activating Factor Acetyl Hydrolase) and CETP (Cholesteryl Ester Transfer Protein). Low HDL-C level is the most prevalent dyslipidemia seen in India and exercise is one reliable way to improve its levels. While acute exercise is known to increase HDL-C levels, not much is known about its effects on HDL functions. This study was aimed at assessing the effect of a single bout of acute aerobic exercise on key HDL functions. Ten healthy adult male volunteers (20-35 years) were made to exercise at 65-80% VO₂ max to expend 200 Kcal using a modified Bruce protocol. Plasma samples were collected at different time points (before exercise, 15 min, 1 hour, 2 hours, 4 hours, 24 hours, 48 hours post-exercise) for analysis of HDL anti-inflammatory function and its related enzyme activities. Friedman ANOVA followed by post-hoc Wilcoxon matched pair test, showed that PON1 activity increased immediately but reached significance 48 hours post-exercise (Z=-2.666, p=0.008). CETP and LCAT activities were decreased significantly at the 4^th hour post-exercise and continued to be low even up to 48 hours (Z=-2.666, p=0.008), whereas HDL-C levels, MPO activity and HDL-II did not vary significantly at different time points. Enhanced activity of the antioxidant enzyme PON1, in combination with decreased activities of pro-atherogenic enzymes CETP and LCAT suggest that even a single bout of acute exercise could be effective in eliciting athero-protective changes in HDL function independent of HDL-C levels.

Keywords

Acute Exercise, Antioxidant Enzymes, CETP, HDL-C, PON1.

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