The Effects of Lamin A/C C1908T Polymorphism on Body Composition, Plasma Lipoprotein Lipid Profile and Insulin Sensitivity Changes with Aerobic Exercise Training

Abstract

Obesity, lipoprotein subclass concentrations and insulin resistance are predictors of cardiovascular disease (CVD). The Lamin A/C (LMNA) C1908T polymorphism has been associated with obesity-related anthropometric and biochemical traits, higher fasting triglyceride, lower HDL-cholesterol concentrations and the metabolic syndrome. Aerobic exercise training has been shown to generate favorable changes in body composition, lipoprotein-lipid profile and insulin sensitivity and to reduce CVD risk. The purpose of this project was to examine the effect of the C1908T polymorphism on percent body fat, plasma lipoprotein-lipid profile and insulin sensitivity in sedentary subjects before, and their change with, 24 weeks of exercise training. Following IRB approval, 144 sedentary adults underwent dietary stabilization, body composition scans, a 3-hour oral glucose tolerance test (OGTT) and plasma lipoprotein-lipid profile analysis. Genotyping was performed using standard techniques. Following baseline testing, 104 subjects completed six months of aerobic exercise training and then underwent a final body composition scan, 3-hour OGTT and plasma lipoprotein-lipid profile analysis. Comparisons were made between C-allele carriers and TT homozygotes; ANOVA and ANCOVA procedures were utilized to examine the effects of the C1908T polymorphism on percent body fat, lipoprotein-lipid profile and insulin sensitivity before, and their changes with, 24-weeks of aerobic exercise training. Statistical significance was set at p≤0.05 level. Overall, genotype frequencies were as predicted by Hardy-Weinberg equilibrium. There were no significant differences between the genotype groups regarding body composition, lipoprotein-lipid profile or OGTT variables at baseline, nor were there significant differences in the change with exercise training of these variables between the two genotype groups. This study suggests that components of the metabolic syndrome and certain CVD risk factors may not be dependent on LMNA A/C genotype. However, a larger and more balanced study population across genotype groups may be needed to reach a definitive conclusion.