Dynamics of Apolipoprotein J Levels and Metabolic Parameters Following Bariatric Surgery

Bariatric surgery has emerged as a potent intervention for ameliorating insulin resistance and its associated comorbidities in obese patients. Apolipoprotein J (ApoJ) and adiponectin are closely associated with insulin resistance and sensitivity, respectively. While changes in adiponectin levels following surgically induced weight loss have been intensively investigated, the response of ApoJ and its impact on metabolic parameters following bariatric surgery remain unclear. We aimed to elucidate serial changes in ApoJ levels and their associations with responses of adiponectin levels and critical metabolic parameters after Roux-en-Y gastric bypass (RYGB) surgery. Seven obese patients undergoing RYGB surgery were enrolled in this prospective study. Clinical and laboratory data were collected before surgery and at multiple time points from 1 day up to 12 months post-surgery. Serum levels of ApoJ, total adiponectin, and its multimeric forms, along with anthropomorphic and other metabolic parameters, were measured in the fasting state.

Post-surgery, marked improvements were observed in anthropometric measures, and in serum levels of glucose, insulin, leptin, GLP-1, adiponectin, and homeostatic model assessment of insulin resistance (HOMA-IR) and insulin secretion (HOMA-ß). While ApoJ levels remained relatively stable, a positive association was seen with changes in leptin levels (r² = 0.499, p = 0.024); no association was found with changes in adiponectin levels.

These findings suggest that although overall ApoJ levels did not change significantly, individual temporal variations were associated with changes in leptin levels, indicating that ApoJ may serve as a potential biomarker after RYGB. Larger studies are needed to validate these observations.