Obstructive sleep apnea and obesity are associated with reduced GPR120 plasma levels in children

Introduction Obstructive sleep apnea (OSA) is a common health problem, particularly in obese children, in whom a vicious cycle of obesity and OSA interdependencies promote increased food intake. GPR120 is a long-chain free fatty acid (FFA) receptor that plays an important role in energy homeostasis, and protects from insulin resistance and systemic inflammation. Thus, we hypothesized that GPR120 levels would be reduced in children with OSA, particularly among obese children. Materials and methods 226 children (mean age: 7.0  ±  2.1 years) underwent overnight polysomnographic evaluation and a fasting blood draw the morning after the sleep study. In addition to lipid profile, HOMA-IR and hsCRP assays, monocyte GPR120 expression and plasma GPR120 levels were assessed using qPCR and ELISA kits. Results Obese children and OSA children had significantly lower GPR120 monocyte expression and plasma GPR120 levels. Furthermore, when both obesity and OSA were concurrently present, GRP120 levels were lowest. Linear associations emerged between GRP120 plasma levels and BMI z score, as well as with AHI, SpO2 nadir, and respiratory arousal index, the latter remaining statistically significant when controlling for age, ethnicity, gender, and BMI z score ( p  0.001). Similarly, HOMA-IR was significantly associated with GRP120 levels, but neither LDL nor HDL cholesterol or hsCRP levels exhibited significant correlations. Conclusion GPR120 levels are reduced in pediatric OSA and obesity, particularly when both are present, and may play a role in modulating the degree of insulin resistance. The short-term and long-term significance of reduced GPR120 in food intake and glycemic deregulation remains undefined. Acknowledgements Supported by National Institutes of Health grants HL-65270, HL-086662, and HL- 107160.