Níveis circulantes de Grelina, índices de adiposidade e fatores de risco cardiovascular e metabólico relacionados, em população multiétnica do Estado do Rio de Janeiro

Abstract

The aim of this study was to analyze the behaviour of ghrelin levels in relation to cardiometabolic risk factors, in a multiethnic population of lean and obese subjects. Ghrelin is a peptide produced mainly by oxyntic gastric cells. It has an important role in energetic balance, stimulating appetite and weight gain, with a role in lipid and carbohydrate metabolism. It interacts directly with the cardiometabolic risk factors. This is a cross-sectional study. Two hundred individuals between 18 and 60 years with varying degrees of body mass index (BMI) comprised the sample, divided as follows: one hundred eutrophic (BMI < 25 kg/m2), 50 men and 50 women and 100 obese (BMI &#8805; 30 kg/m2), 50 men and 50 women. All were evaluated by anthropometric parameters, blood pressure determination (measured by the oscilometric method using an automatic monitor) and metabolic variables (usual methods certificates). The acylated ghrelin was measured by sandwich ELISA technique; leptin by Milliplex MAP method. The inflammatory marker sensitive C reactive protein (hsCRP) was estimated by ultrasensitive nephelometry. Insulin was determined by quimioluminescency and HOMA-IR calculated as the product of insulin (µU/ml) X fasting glucose levels (mmol/L) / 22.5. Those subjects with a history of chronic comorbidities, acute inflammatory diseases, drug addiction and on medication in the ten days prior to study entry were withdrawn from the study. There was a trend of decreasing acylated ghrelin (P<0,001) and increasing leptin levels (P<0,001), respectively, along increasing degrees of adiposity. Acylated ghrelin levels were negatively correlated with BMI (r = -.36; P<0,001), waist circumference (r=-.34; P<0,001), waist-to-hip ratio (r=-.22; P=0,001), sagittal abdominal diameter (r=-.28; P<0,001) , systolic blood pressure (r=-.21; P=0,001) , insulin (r=-.27; P<0,001), HOMA-IR (-.24; P=0,001) and high sensitive C reactive protein (hsCRP) (r=-.29; P<0,001); the correlation of acylated ghrelin with HDL-cholesterol was positive (r=.30; P<0,001).The hsCRP followed insulin resistance degree and acyated ghrelin levels also showed decreasing linear trend along increasing HOMA-IR tertiles (P=0,001). In a linear multiple regression model the independent positive correlates of ghrelin were female sex (P=0,005) and HDL-cholesterol (P=0,008), while BMI associated negatively and independently with ghrelin levels (P<0,001). These findings suggest an association of ghrelin with a better metabolic profile, since its levels were positively correlated with HDL-cholesterol and negatively associated with insulin resistance and inflammatory activity indicators.