Comparison of serum irisin, betatrophin and lipocalin-2 levels in normal-weight and obese subjects and their relationship to nutritional status and serum lipid profile and fasting blood sugar

Abstract

Introduction: Obesity is a multifactorial disease, caused by an imbalance between energy intake and energy expenditure. Obesity is considered as a risk factor for many chronic diseases. Several hormones are secreted from various tissues of the body as well as from the adipose tissue that influence the metabolism of adipose tissue and play a role in pathophysiology, prevention and management of obesity. Nowadays, the importance of irisin, betatrophin and lipocalin-2 in termogenesis, proliferation of pancreatic beta cells, insulin secretion and inflammatory processes have been reported. Considering the high prevalence of obesity and the importance of hormones and the limited evidence, the aim of this study was to compare the serum levels of these factors in normal and obese groups and their relation with anthropometric indices and lipid and glucose factors. Methods: In the present descriptive-analytical research, 90 male and female participants aging 20-55 years were included in 2 groups with normal BMI and grade-1 obesity (n=45 each grops). The groups were matched based on sex and gender. Weight, height, waist and hip circumference, serum levels of irisin, betatrophin and lipocalin-2, lipid profile and blood sugar were measured in participants. Then BMI, abdominal indices and atherogenic indices were calculated. Physical activity was measured via International Physical Activity Questionnaire (short form) and Food intake was measured via a Food Frequency Questionnaire and the data were analyzed using SPSS (version 24) software. Results: In this study, serum levels of irisin and betatrophin were significantly (P <0.005) higher in the normal group, whereas serum levels of lipocalin-2 in obese group were significantly (P <0.005) more than normal group. In the whole population, there was a significant and inverse correlation between serum irisin and anthropometric indices, triglyceride, total cholesterol (TC), total energy and macronutrient intake.In case of betatrophin, there was a significant and inverse correlation between betatrophin serum levels and anthropometric indices, TC, total energy and fat intake. However, contrary to these two factors, there was a positive and significant correlation between serum lipocalin-2 levels and anthropometric indices, triglyceride, total energy and macronutrient intake. No significant association was observed between serum levels of irisin, betatrophin and lipocalin-2 and fasting blood sugar. Conclusion: In conclusion, serum levels of irisin, betatrophin and lipocalin-2 were significantly different between groups and had a significant relationship with some anthropometric and biochemical indices. However, further studies on the role of these factors in the pathophysiology of obesity and its treatment are necessary.