Avaliação da expressão de componentes do sistema Renina-Angiotensina (SRA) na placenta e no tecido adiposo de gestante com obesidade e sua correlação com parâmetros clínicos, laboratoriais, antropométricos e histológicos

Abstract

Maternal obesity has shown an increase in prevalence rates in recent decades, especially due to lifestyle changes, such as a sedentary lifestyle and hypercaloric diets. It is associated with unfavorable maternal-fetal outcomes and may impact the development of offspring in adult life, predisposing them to obesity, diabetes, and cardiovascular diseases. Obesity strongly influences the phenotype of various body tissues, mainly due to the production of adipokines, which are produced locally and remotely, modulating various pathophysiological processes, such as insulin resistance and inflammation. The Renin-Angiotensin System (RAS) comprises a peptide cascade, made up of several components expressed in many body tissues. The present study aimed to evaluate the expression of RAS components in the placental and white adipose (omentum) tissues of women with or without obesity and to correlate their levels with anthropometric, clinical, laboratory, and histological parameters. For that, an analytical cross-sectional study was carried out with women who a public maternity hospital in the city of Vitória da Conquista, Bahia, Brazil. There were 39 participants divided into two groups: a) without obesity (n=18) and with obesity (n=21). For pregnant women, clinical and laboratory information was collected from the prenatal card and the medical record. For newborns, anthropometric samples were obtained. In addition, samples of placental tissue and greater omentum obtained at the time of delivery were collected. For these samples, there was only one collecting obstetrician. The expression of RAS markers, Angiotensin Converting Enzyme (ACE), and ACE2 was measured by qRT-CPR. Also, the tissue samples were submitted for histological analysis and the inflammatory cell count was performed. The results showed higher ACE expression and lower ACE2 expression in the placenta and adipose tissue in the group of obese women. In the correlation analysis between the levels of ACE and ACE2 between the tissues, no statistically significant difference was found. As a result, correlation analyses of maternal-fetal clinical, laboratory, and anthropometric variables and levels of ACE and ACE2 expression in adipose tissue did not show a statistically significant association. As for the placenta, a negative correlation was observed between ACE2 expression levels and pre-pregnancy BMI (r=-0.351; p=0.029) and total cholesterol (r=-0.364; p=0.024). Finally, no statistically significant difference was observed in the percentage of inflammatory cells in the placenta and adipose tissue; moreover, no correlation was observed between the expression levels of ACE and ACE2 with the percentage of inflammatory cells in the placenta and adipose tissue. It is concluded that maternal obesity can modulate the expression of RAS components, interfering with parameters such as pre-gestational BMI and total cholesterol levels. Furthermore, ACE and ACE2 levels were not associated with tissue inflammatory cell counts.