The rs1862513 Variant in Resistin Gene-Modified Insulin Resistance and Insulin Levels after Weight Loss Secondary to Hypocaloric Diet

Abstract

Background/Aims: Polymorphisms of a single nucleotide in RETN have been associated with indexes of insulin resistance. Our aim was to analyze the effects of the rs1862513 RETN gene polymorphism on insulin resistance, insulin levels, and resistin levels changes after 3 months of a low-fat hypocaloric diet. Design: A Caucasian population of 133 obese patients was analyzed before and after 3 months on a low-fat hypocaloric diet. Results: Fifty-six patients (42.1%) had the genotype GG (wild group) and 77 (57.9%) patients had the other genotypes; GC (59 patients, 44.4%) or CC (18 patients, 13.5%; mutant group). In wild and mutant genotype groups, weight, body mass index, fat mass, waist circumference, and systolic blood pressure decreased. In the wild genotype group, the decrease in total cholesterol was -13.1 ± 25.3 mg/dL (vs. -4.4 ± 13.7 mg/dL in mutant group: p = 0.004 for group deltas), low density lipoprotein (LDL)-cholesterol was -13.0 ± 21.5 mg/dL (-4.3 ± 10.5 mg/dL: p = 0.007), glucose -7.2 ± 3.5 mg/dL (-0.8 ± 0.2 mg/dL: p = 0.01), insulin -5.6 ± 2.5 mUI/L (-2.9 ± 1.2 mUI/L: p = 0.03) and homeostasis model assessment-insulin resistance (HOMA-IR) -2.5 ± 1.1 (-0.6 ± 1.4: p = 0.02). Leptin levels decreased in both genotypes (-10.1 ± 9.5 ng/dL in wild type group vs. -13.1 ± 0.2 ng/dL in mutant type group: p > 0.05). Conclusion: The present study suggests that the G/G genotype of RETN rs1862513 could be a predictor of the reduction of HOMA-IR, insulin, fasting glucose and LDL cholesterol secondary to a hypocaloric diet in obese subjects.