[Structural changes of gut microbiota after gastric bypass in obese patients with type 2 diabetes].

OBJECTIVE: To investigate the structural changes inintestinal flora and metabolic changes in type 2 diabetic patients with obesity(BMI≥40 kg/m2)by sequencing the 16S rRNA genes. METHODS: Stool samples were collected from 4 diabetic patients before and after gastric bypass surgery for extraction of the total DNA. The diversity of the intestinal flora in the samples was investigated by 16S rRNA sequencing. After surgery, the changes in glucose and lipid metabolism were evaluated in the patients, and the changesin body mass index (BMI) and waist to hip ratio were assessed at 3 month intervals. RESULTS: After gastric bypass, the patient's BMI, waist to hip ratio, glucose metabolism and lipid metabolism gradually recovered the normal levels. The proportion of Bacteroidetesis increased and the proportions of Firmicutes and Proteobacteria decreased in the intestinal bacteria after the surgery. CONCLUSION: Gastric bypass surgery can effectively alleviate the condition of obese patients with type 2 diabetes and improve the composition of the intestinal flora.

[Efficacy of two bariatric surgeries in type 2 diabetic patients with a body mass index of 25-27.5].

OBJECTIVE: To evaluate the therapeutic effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic duodenal-jejunal bypass with sleeve gastrectomy (SADJB-SG) in patients with type 2 diabetes mellitus and a low body mass index (BMI) of 25-27.5. METHODS: Thirty-one type 2 diabetic patients with a BMI of 25-27.5 underwent bariatric surgeries in the General Hospital of Guangzhou Military Command between August, 2013 and August, 2015. The patients receiving LRYGB (17 cases) and SADJB-SG (14 cases) were compared for physical indexes, glucose metabolism and of pancreatic islet function at 1 year after the surgeries. RESULTS: No mortality occurred in the patients after the operations. At 1 year after the operation, the patients in LRYGB group showed significant improvements in body weight, BMI, glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), oral glucose tolerance test 2 h (OGTT2h), C-peptide, fasting insulin (FINS), and postprandial 2 hour insulin (2 hPINS) (P<0.05); in SADJB-SG group, significant improvements were observed in the body weigh, BMI, HbA1c, FPG, OGTT2h, and FINS after the operation (P<0.05). The postoperative improvements in body weigh, BMI, HbA1c, FPG, OGTT2h, C-peptide, and 2hPINS were comparable between SADJB-SG group and LRYGB group (P>0.05), but the incidence of postoperative anastomotic ulcer was lower in SADJB-SG group. CONCLUSION: SADJB-SG and LRYGB produce similar therapeutic effects in type 2 diabetic patients with a low BMI, but SADJB-SG is associated with a low incidence of postoperative complications and is therefore more suitable in such patients.

B cells present skewed profile and lose the function of supporting T cell inflammation after Roux-en-Y gastric bypass.

Bariatric surgeries, including Roux-en-Y gastric bypass (RYGB) are currently the best treatment for obesity and obesity-related comorbidities, such as type 2 diabetes. However, the underlying mechanism of bariatric surgeries is not entirely understood. Further investigations are needed to improve the success rate and achieve sustained health benefits. Given that B cell dysregulation is a critical component of etiology in inflammatory diseases, whereas obesity and type 2 diabetes represent two major inflammatory disorders, we investigated the effect of RYGB on B cell inflammation. We found that B cells after RYGB presented significantly elevated frequency of interleukin (IL)-10-producing cells and reduced frequency of IL-6-producing cells compared to those before RYGB. When grouping B cell subsets into regulatory (secreting IL-10 and transforming growth factor beta [TGF-ß]) and effector (secreting IL-2, IL-4, IL-6, IL-12, interferon gamma [IFN-γ] and tumor necrosis factor alpha [TNF-α]) types, we found that after RYGB, the regulatory to effector B cell ratio was significantly increased. Function analyses showed that B cells before RYGB supported IL-17 secretion from T cells whereas these cells after RYGB lost such capacity. B cells after RYGB also gained the capacity to suppress T cell IFN-γ production through TGF-ß-mediated effects, a feature not present in B cells before RYGB. Interestingly, the regulatory to effector B cell ratio was directly associated with the reductions in obesity markers following RYGB, such as BMI and fat mass percentage. Together, these results demonstrated a potential mechanism through which RYGB promoted amelioration of obesity and type 2 diabetes.

Profiling peripheral microRNAs in obesity and type 2 diabetes mellitus.

Mechanisms of type 2 diabetes mellitus (T2DM) remain elusive, in which obesity (OB) is considered as one of the major risk factors for the disease. A microRNA (miRNA) is a small non-coding RNA molecule functioning in RNA silencing and post-transcriptional regulation of gene expression. It has been demonstrated that some miRNAs can exist in serum stably and is closely related to various diseases. The goal of our study was to identify whether the deregulation of serum miRNAs was associated with T2DM and obesity. Twenty-five subjects with T2DM2, 25 healthy controls, 25 subjects with obesity, and 25 subjects with T2DM combined with obesity were included in the study. A total of 536 miRNA serum samples from these four groups were studied by miRNA polymerase chain reaction (PCR) panels. Data showed that miR-152 and miR-17 were significantly elevated in the OB group, whereas miR-138 was significantly decreased in OB group when compared to controls, T2DM, or T2DM+obesity group. In addition, level of MiR-593 was significantly lower in T2DM group and T2DM+obesity group when compared with controls. Further analysis revealed that the four miRNAs can be used as potential biomarkers to distinguish obesity from T2DM, OB+T2DM, and healthy subjects. Our study is one of the pioneer studies showing the differences in peripheral miRNA level in obesity, T2DM and T2DM combined with obesity. The study results suggest the potential utility of miRNAs in the prediction for obesity and T2DM.