The Ala55Val and -866G>A polymorphisms of the UCP2 gene could be biomarkers for weight loss in patients who had Roux-en-Y gastric bypass

Abstract

Objective: The aim of this study was to investigate whether the Ala55Val and -866G>A polymorphisms of the UCP2 gene are related to weight loss and changes in body composition after bariatric surgery performed by Roux-en-Y gastric bypass (RYGB).

Methods: This longitudinal study enrolled obese patients submitted to RYGB. Data regarding weight (kg), body mass index (kg/m²), fat-free mass (FFM; kg), fat mass (kg), weight loss (kg and %), and percent excess weight loss were collected from both preoperative and 1-y postoperative medical records. Polymorphisms were genotyped by allelic discrimination using real-time polymerase chain reaction and TaqMan-predesigned single nucleotide polymorphism Genotyping Assay kits (Applied Biosystems, Foster City, CA, USA). The t test was used to compare variables between genotypes of each polymorphism to analyze the dominant and recessive models. Linear regression models were used to adjust the effects of initial weight, age, and sex on the variation of weight and body composition (P < 0.05).

Results: We analyzed 150 severely obese individuals (age 47.2 ± 10.5 y; 80% women). Genotype analysis showed a greater prevalence of heterozygous GA (41.3%) for -866G>A polymorphism and CT (39.3%) for Ala55Val polymorphism. Individuals who carried the T (CT+TT) and A (GA+AA) mutated alleles for Ala55Val and -866G>A, respectively, showed a higher weight and FFM loss.

Conclusion: The mutated alleles T for Ala55Val and A for -866G>A polymorphism could be biomarkers of weight loss 1 y after RYGB.

Keywords: Bariatric surgery; Biomarker; Obesity; UCP2 polymorphism; Weight loss.