Role of the electronegative low-density lipoprotein, cholesteryl ester transfer protein and insulin resistance in the cardiometabolic risk of the adolescents

Author(s)

Ana Paula de Queiroz Mello

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
• Defense date: 2011-10-24

Examining board members

Nágila Raquel Teixeira Damasceno; Marcelo Chiara Bertolami; Francisco Antônio Helfenstein Fonseca; Raul Cavalcante Maranhao; Ligia Araujo Martini

• Advisor: Nágila Raquel Teixeira Damasceno

Abstract

Introduction: Obesity is a major public health problem and, according to World Health Organization, represents a global epidemic. It is considered a chronic, multifactorial disease, which depends not only of genetic and pathophysiology factors, but also of cultural, social and psychological associated with diet profile variables. In this context, adolescents as the focus of physiological, anatomical and social changes become a group with high frequency of risk factor for obesity. Objective: To evaluate the role of the electronegative low-density lipoprotein [LDL(-)] concentration, cholesteryl ester transfer protein (CETP) activity and insulin resistance on cardiometabolic risk of adolescents. Methods: We recruited adolescents of both sexes, aged 10 to 19 years and enrolled in schools in the city of São Paulo. Anthropometric measurements such as weight, height, waist circumference (WC) and body composition were evaluated and classified according to sex and age. After fasting (12-15h) was analyzed from plasma: glucose, insulin and HOMA, lipid profile, apolipoprotein A-I and B, paraoxonase 1 activity (PON1), non-esterified fatty acids (NEFA), CETP activity and LDL(-). The results were analyzed by chi-square, Kappa, Kolmogorov-Smirnov, t-student, ANOVA, Mann-Whitney, Kruskal-Wallis, Bonferroni and linear tendency test, with p< 0.05. Results: The subjects with normal weight had lower CETP activity and content of LDL(-) than excess weight adolescents. BMI showed positive and linear association with TC/HDL-C, TG/HDL-C, ApoB/ApoA-I, LDL(-) and LDL(-)/TC. Profile opposite was observed for HDL-C and ApoA-I. The WC was positively associated with TG, TC/HDL-C, LDL-C/HDL-C, TG/HDL-C, ApoB/ApoA-I, LDL(-), LDL(-)/CT and CETP. Negative association was observed between WC and HDL-C and ApoA-I. After adjustment for CETP, associations between HDL-C, LDL-C/HDL-C, TC/HDL-C and LDL(-)/LDL-C with BMI or WC were modified. Adjustment for LDL(-) content was not able to change these associations, suggesting an independent mechanism for regulation of the levels of this particle during obesity. Analysis second WC, it was found that adolescents 10 with WCHIGH showed higher BMI, per cent body fat, systolic blood pressure, insulin, HOMA, TG, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C, ApoB/ApoA-I, NEFA, LDL(-), LDL(-)/TC and CETP activity than WCLOW group. Profile opposite was observed for per cent lean body mass, HDL-C, ApoA-I, HDL/ApoA-I and PON-1. When it classified according to HOMA (insulin resistant IR and insulin sensitive IS), IR group showed a negative impact on BMI, WC, per cent body fat, blood pressure, TG and TG/HDL-C, and contrary result for per cent mass lean and PON1. The cardiovascular risk index propose showed that WCHIGH IR = WCHIGH IS > WCLOW IR = WCLOW IS group. Conclusions: Therefore, LDL(-) content and CETP activity associated with obesity, mainly abdominal, alter the cardiometabolic risk of adolescents (AU)