Bariatric Surgery Alters microRNA Content of Circulating Exosomes in Patients with Obesity

OBJECTIVE: Exosomal microRNAs (miRNAs) are potential biomarkers for obesity, in which they regulate biological processes. Bariatric surgery has health benefits for patients with obesity; however, the mechanisms of these benefits are not clear. This study attempted to identify the exosomal miRNA signature associated with obesity and how it changed after bariatric surgery. METHODS: Healthy volunteers (HVs) and nondiabetic patients with obesity were prospectively enrolled in the study. The study assessed the serum exosomal miRNA profiles of HVs and patients with obesity using RNA sequencing. To evaluate the effects of bariatric surgery, the study also analyzed exosomal miRNAs in patients 6 months after surgery. RESULTS: RNA sequencing revealed differential expression of 72 exosomal miRNAs in patients with obesity compared with HVs and differential expression of 41 miRNAs in post- versus presurgery blood. Among the differentially expressed miRNAs, the study identified nine surgery-responsive miRNAs that were highly expressed in patients before surgery compared with HVs. Biological pathway analysis of the nine miRNAs indicated that they are likely involved in WNT, neurotrophin, and insulin signaling; the insulin receptor signaling cascade; and focal adhesion. CONCLUSIONS: Patients with obesity have a distinct exosomal miRNA expression profile compared with HVs. In addition, weight loss after surgery alters the exosomal miRNA profile of patients with obesity.