Effect of Contemporary Bariatric Surgical Procedures on Type 2 Diabetes Remission. A Population-Based Matched Cohort Study.

OBJECTIVE: The objective of the study is to evaluate the effect of gastric banding, gastric bypass and sleeve gastrectomy on medium to long-term diabetes control in obese participants with type 2 diabetes mellitus. RESEARCH DESIGN AND METHODS: Matched cohort study using primary care electronic health records from the UK Clinical Practice Research Datalink. Obese participants with type 2 diabetes who received bariatric surgery from 2002 to 2014 were compared with matched control participants who did not receive BS. Remission was defined for each year of follow-up as HbA1c <6.5 % and no antidiabetic drugs prescribed. RESULTS: There were 826 obese participants with T2DM who received bariatric surgery including adjustable gastric banding (LAGB) 220; gastric bypass (GBP) 449; or sleeve gastrectomy (SG) 153; with four procedures undefined. Mean HbA1c declined from 8.0 % before BS to 6.5 % in the second postoperative year; proportion with HbA1c <6.5 % (<48 mmol/mol) increased from 17 to 47 %. The proportion of patients in remission was 30 % in the second year, being 20 % for LAGB, 34 % for GBP and 38 % for SG. The adjusted relative rate of remission over the first six postoperative years was 5.97 (4.86 to 7.33, P < 0.001) overall; for LAGB 3.32 (2.27 to 4.86); GBP 7.16 (5.64 to 9.08); and SG 6.82 (5.05 to 9.19). Rates of remission were maintained into the sixth year of follow-up. CONCLUSIONS: Remission of diabetes may continue for up to 6 years after bariatric surgical procedures. Diabetes outcomes are generally more favourable after gastric bypass or sleeve gastrectomy than LAGB

Structure and functional characterization of pyruvate decarboxylase from Gluconacetobacter diazotrophicus

BACKGROUND: Bacterial pyruvate decarboxylases (PDC) are rare. Their role in ethanol production and in bacterially mediated ethanologenic processes has, however, ensured a continued and growing interest. PDCs from Zymomonas mobilis (ZmPDC), Zymobacter palmae (ZpPDC) and Sarcina ventriculi (SvPDC) have been characterized and ZmPDC has been produced successfully in a range of heterologous hosts. PDCs from the Acetobacteraceae and their role in metabolism have not been characterized to the same extent. Examples include Gluconobacter oxydans (GoPDC), G. diazotrophicus (GdPDC) and Acetobacter pasteutrianus (ApPDC). All of these organisms are of commercial importance. RESULTS: This study reports the kinetic characterization and the crystal structure of a PDC from Gluconacetobacter diazotrophicus (GdPDC). Enzyme kinetic analysis indicates a high affinity for pyruvate (KM 0.06 mM at pH 5), high catalytic efficiencies, pHopt of 5.5 and Topt at 45 degrees C. The enzyme is not thermostable (T of 18 minutes at 60 degrees C) and the calculated number of bonds between monomers and dimers do not give clear indications for the relatively lower thermostability compared to other PDCs. The structure is highly similar to those described for Z. mobilis (ZmPDC) and A. pasteurianus PDC (ApPDC) with a rmsd value of 0.57 A for C? when comparing GdPDC to that of ApPDC. Indole-3-pyruvate does not serve as a substrate for the enzyme. Structural differences occur in two loci, involving the regions Thr341 to Thr352 and Asn499 to Asp503. CONCLUSIONS: This is the first study of the PDC from G. diazotrophicus (PAL5) and lays the groundwork for future research into its role in this endosymbiont. The crystal structure of GdPDC indicates the enzyme to be evolutionarily closely related to homologues from Z. mobilis and A. pasteurianus and suggests strong selective pressure to keep the enzyme characteristics in a narrow range. The pH optimum together with reduced thermostability likely reflect the host organisms niche and conditions under which these properties have been naturally selected for. The lack of activity on indole-3-pyruvate excludes this decarboxylase as the enzyme responsible for indole acetic acid production in G. diazotrophicus.IS