Molecular markers related to energy metabolism and its association with substrate oxidation and resting metabolic rate in women with grade III obesity before and after bariatric surgery

Author(s)

Bruno Affonso Parenti de Oliveira

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2022-07-01

Examining board members

Carla Barbosa Nonino; Rebeca Antunes Beraldo; Eduardo Rochete Ropelle

• Advisor: Carla Barbosa Nonino

Abstract

The analysis of the expression of energy metabolism genes by microarray and subsequent association with resting metabolic rate (RMR) and substrate oxidation may help to elucidate factors that influence obesity. In this sense, the aim of the present study was to analyze molecular markers related to energy metabolism and their association with substrate oxidation and RMR in women with grade III obesity, before and after bariatric surgery. The sample consisted of 22 women divided into two groups, group 1 (G1), composed of 13 obese women, before and after six months of bariatric surgery, and group 2 (G2) composed of 9 eutrophic women. This is a longitudinal study, in which all participants were evaluated regarding anthropometry, body composition, RMR and oxidation of substrates by indirect calorimetry. In addition, blood collection and subsequent RNA extraction were performed for gene expression analysis by microarray chip. Expression changes were calculated in fold change and real-time PCR validation. Significant differences were observed in the variables weight, BMI, AC, FFM(kg), FFM(%), FM(kg), FM(%), VO2(L/min), VCO2(L/min), RMR(kcal), RMR(kcal/kg), QR, Oxid. lip. (g/day), Oxid. total/weight, triglycerides (mg/dL) between groups and pre- and post-surgery six months. Still, 1188 upregulated genes were identified, among them, six genes related to energy metabolism, eight genes related to lipid and carbohydrate metabolism and twenty genes related to protein metabolism. There was a contribution of the six genes related to energy metabolism in the RMR in absolute values (p=0.02) and adjusted by weight (p=0.04) at the postoperative moment. However, no relationships were found between lipid and carbohydrate metabolism genes with body composition and substrate oxidation. Finally, there was a positive correlation between triglycerides and MLX (r=0.74, p=0.01) and a negative correlation between blood glucose and LEP (r= -0.68, p=0.01). It is concluded that bariatric surgery increases the expression of genes related to energy metabolism and influences postoperative RMR. (AU)

• FAPESP's process: 15/06624-1 - Molecular markers related to energy metabolism and its association with substrate oxidation and resting metabolic rate in women with morbid obesity before and after bariatric surgery
• Grantee: Bruno Affonso Parenti de Oliveira
• Support Opportunities: Scholarships in Brazil - Doctorate