The Role of Secreted Frizzled-Related Protein 5 (Sfrp5) in Overweight and Obesity in Childhood and Adolescence

Background/Objective: Secreted frizzled-related protein 5 (Sfrp5) is an anti-inflammatory adipokine that has been implicated in the pathophysiology of obesity and its metabolic complications. Despite the fact that numerous studies have been carried out in adults, limited data on Sfrp5 exist for youth, especially in relation to overweight and obesity. Methods: In our study, we assessed the concentrations of Sfrp5, total oxidative (TOS) and antioxidative (TAS) status, high-sensitivity C-reactive protein (hs-CRP), and several cytokines (IL-1 alpha, IL-1 beta, IL-2, IL-6, IL-8, IL-12, TNF-alpha) in 120 children and adolescents (mean age +/- SE: 11.48 +/- 0.25 years; 48 prepubertal, 72 pubertal; 74 males and 46 females) before and 1 year after the implementation of a personalized, structured, lifestyle intervention program of healthy diet, sleep, and physical exercise. Results: Based on the body mass index (BMI), participants were categorized as having morbid obesity (n = 63, 52.5%), obesity (n = 21, 17.5%), overweight (n = 22, 18.33%), or normal BMIs (n = 14, 11.67%), based on the International Obesity Task Force (IOTF) cut-off points. Following the 1-year lifestyle intervention program, a significant improvement in anthropometric measurements (BMI, BMI-z score, diastolic blood pressure, WHR, and WHtR), body-composition parameters, hepatic enzymes, lipid profile, inflammation markers, and the insulin-sensitivity profile (HbA1C, HOMA index) was observed in all subjects. Sfrp5 decreased in subjects with obesity (p < 0.01); however, it increased significantly (p < 0.05) in patients with morbid obesity. Linear regression analysis indicates that TNF-alpha and systolic blood pressure were the best positive predictors and hs-CRP was the best negative predictor for Sfpr5 concentration at initial assessment and glucose concentration for Delta Sfrp5, while TNF-alpha and TAS were the best positive predictors for Sfpr5 concentration at annual assessment. Conclusions: These results indicate that Sfrp5 is associated with severe obesity and is increased following weight loss in children and adolescents with morbid obesity. It is also related to metabolic homeostasis, as well as inflammation and oxidative status.