Arginase I and the very low-density lipoprotein receptor are associated with phenotypic biomarkers for obesity

Objective: Obesity is a serious health problem implicated in many metabolic disorders (i.e., hypertension, dyslipidemia, and cardiovascular disease). We examined whether the mRNA of tested genes were linked to blood lipid concentrations and vascular endothelial function as features of obesity. Methods: In healthy subjects (30-69 y old; normal weight, n = 22, body mass index 18.5-23 kg/m ²; overweight, n = 25, body mass index ≥23 kg/m ²) the following parameters were measured in the blood circulation: total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, apolipoprotein AI, apolipoprotein B, adiponectin, high-sensitivity C-reactive protein, and soluble intercellular adhesion molecule-1. The mRNA levels of genes (arginase I [ARG1], very low-density lipoprotein receptor [VLDLR], adiponectin receptor-1 [ADIPOR1], ADIPOR2, and nitric oxide synthase-3 [NOS3]) were tested in the subjects' peripheral blood mononuclear cells. Results: The expression levels of all tested genes were investigated for their associations with the blood concentrations of each parameter. In the expression study, only ARG1 (4.5-fold) and VLDLR (4-fold) expressions were significantly upregulated in the overweight group compared with the normal-weight group. The ARG1 mRNA levels were positively associated with blood concentrations of total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and soluble intercellular adhesion molecule-1. The VLDLR mRNA levels showed a positive relation with triacylglycerol and glucose concentrations and a negative relation with adiponectin levels. Conclusion: Significant upregulations of ARG1 and VLDLR were observed in the overweight condition and their expression levels are likely to be closely linked to the phenotypic biomarkers for obesity (disturbed lipid profiles and endothelial dysfunction).