Bariatric surgery effect on associated with obesity microRNA levels

Objective: In this study, it was aimed to evaluate the relationship between miRNA expression levels associated with obesity and weight loss, to predict how much weight patients can lose postoperatively and to get maximum benefit from planned surgery. Materials and Methods: Between May 2017-July 2018, 17 patients who were indicated for bariatric surgery and planned laparoscopic sleeve gastrectomy at Bezmialem Vakıf University, Faculty of Medicine, Department of General Surgery, Obesity and Metabolic Surgery Polyclinic were included in this study. The study was approved by Bezmialem Vakıf University Faculty of Medicine Ethics Committee. Preoperative and postoperative 6th month blood samples and intraoperative adipose tissue samples were obtained. The expression levels of miRNA (miR27b-3p, miR122-5p, miR223-3p) associated with obesity were examined. The miRNAs were isolated from blood and adipose tissue and quantitated and analyzed by real-time polymerase chain reaction (RT-PCR) method. Postoperative 6th month excess weight loss rates (%EWL) were evaluated in three groups as %0-50 (group-1), %50-70 (group-2), %70-90 (group-3) respectively. The differences of miRNA expressions between blood and adipose tissues, gender, excess weight loss rates, and relationship with diabetes mellitus were examined. Results: 4 of the patients were male (%23.5), 13 were female (%76.4), male/female ratio 0.3, average age 41±11,6, average body mass index 49,1±7,6 kg/m2. Diabetes mellitus was present in 6 patients (35.2%) and their mean glucose and HbA1c values were 133 ± 59.4 mg / dl and 6.4 ± 1.3 %, respectively. The sixth month EWL rate was an average of %62.7±17. There were 4, 7 and 6 patients in groups 1, 2 and 3, respectively. The expression of miR223-3p was found significantly higher among all preoperative groups (p = 0.0046 for group-1; p <0.0001 for group-2; p = 0.0017 for group-3). MiR223-3p gene expression levels evaluated in preoperative and postoperative blood samples in group-2 and group-3 were found to be statistically significantly higher than miR27b-3p and miR122-5p gene expressions (p values for group-2 are p = 0.0335 and p = 0.0328 respectively, p values for group-3 are p=0.0446 and p = 0.0441 respectively). In addition, miR122-5p gene expression in fatty tissue was found to be less expressed than other miRNAs in patients with diabetes mellitus (p = 0.0062). Conclusion: Expression of miR223-3p has been shown to correlate with morbidly obese patients, particularly with patients with an EWL of 50% and above. For this reason, miR223-3p gene can be used as a possible biomarker in predicting weight loss after bariatric surgery. Thus, the group of patients who will benefit more from surgery can be determined in advance and the effectiveness of surgery can be increased. In addition, groups that will not benefit from surgery can be identified and combined (restrictive + malabsorbtive) or malabsorbtive surgical procedures may be preferred instead of restrictive bariatric surgery procedures in these patients. However, further studies with high number of cases, more types of miRNA and applied different bariatric surgery procedures are needed.