282-LB: Analysis of Cell-Free Mitochondrial DNA in Obese Patients With and Without Type 2 Diabetes after Bariatric Surgery

Abstract

While the improvement of mitochondrial function after bariatric surgery was shown, there is limited evidence about the metabolic effects of bariatric surgery on circulatory cell-free (cf) mitochondrial DNA (mtDNA). Therefore, the goal of this study was to compare plasma levels of cf-mtDNA in the association to the metabolic changes before and after surgery in obese patients. Plasma was isolated from 13 morbidly obese bariatric surgery patients with and without type 2 diabetes (T2D) and 8 healthy controls (HC). From each obese patient, blood was collected at baseline, 2 weeks, 3 and 6 months after surgery. QRT-PCR was used to quantify short cf-mtDNA (~100 bp) in isolated plasma within the ND6 region. At baseline, plasma level of short cf-mtDNA fragments was significantly higher in obese patients compared to HC. Additionally, when obese patients were grouped by presence or absence of T2D and compared to HC patients, plasma ND6 levels were significantly higher in obese T2D but not in non-T2D group. Bariatric surgery reduced BMI and improved insulin sensitivity and other whole-body metabolic parameters in all obese patients. No significant variation in mean ND6 values over time was observed post-surgery in all obese patients or when we plotted the data according to the T2D and non-T2D. Importantly, significant positive correlation was observed between plasma ND6 level and HOMA-IR but only 2 weeks post-surgery. Interestingly, plasma from both HC and obese groups at all time points post-surgery contain long (~8 kb) cf-mtDNA fragments, suggesting the presence of near intact and/or whole mitochondrial genomes. Overall, bariatric surgery decreased weight and improved insulin sensitivity and other metabolic parameters in obese patients without significant change in plasma cf-mtDNA levels. Further studies need to test potential determinants, characteristics and origin of cf-mtDNA associated with postoperative metabolic improvements following surgery. Disclosure L. Yuzefovych: None. V. M. Pastukh: None. W. Richards: Research Support; Ethicon, Inc. L. Rachek: None. Funding University of South Alabama (807 to L.R., W.R.)