Effect of biliopancreatic diversion in the beta-cell function of grade I and II obese women with type 2 diabetes mellitus

Author(s)

Ana Carolina Junqueira Vasques

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2013-02-25

Examining board members

Bruno Geloneze Neto; Marcio Correa Mancini; Walmir Ferreira Coutinho; João Eduardo Nunes Salles; Daniéla Oliveira Magro

• Advisor: Bruno Geloneze Neto; José Carlos Pareja

Abstract

Objective: to assess the effect of biliopancreatic diversion surgery (BPD) in beta-cell function of obese grade I and II women with type 2 diabetes mellitus (T2DM), using an oral and an intravenous stimuli with glucose. Research Design and Methods: sixty eight premenopausal women were assessed and divided into three groups: lean control - LeanC (n = 19; BMI: 23.0 ± 2.2 kg/m²), obese control - ObeseC (n = 18; BMI: 35.0 ± 4.8kg/m²), both with normal glucose tolerance; and obese with type 2 diabetes - ObeseT2DM (n = 31; BMI: 36.3 ± 3.7 kg/m²). In ObeseDM2 group, 64% of women underwent BPD (n = 20, BMI: 36.5 ± 3.7 kg/m²). The 68 volunteers underwent all assessments once. The volunteers those underwent BPD were reassessed one month after surgery. The assessment of beta-cell function was performed by dynamic tests with an oral (oral glucose tolerance test) and an intravenous stimulation test (hyperglycemic clamp). Serum glucose, insulin and C-peptide were determined. The application of mathematical modeling techniques to data allowed to evaluate basal, dynamic and static (oral stimulus) insulin secretion; the first and second phase of insulin secretion (intravenous stimulus); the total insulin secretion; the insulin sensitivity (IS); the hepatic extraction of insulin (EH) and the delay time for the beta-cell to recruit new insulin granules to form the pool of readily releasable granules in response to a given plasma glucose. Results: after BPD, there was a dramatic improvement on IS during the OGTT and during the clamp test, with the surgical group reaching normalized levels compared to those observed in LeanC group and higher levels than ObeseC group (p < 0.05). The EH of insulin showed significant improvement after BPD, with the surgical group reaching similar levels to LeanC and with increased levels in comparison to ObeseC (p < 0.05). The basal insulin secretion achieved normalized levels, with the surgical group resembling the LeanC group. There was improvement in stimulated beta-cell function (p < 0.05), independent of the route of glucose administration (oral and intravenous). The delay time presented no improvement after BPD. Conclusion: several positive physiological adaptations occurred after BPD surgery. These adaptations are related to restoration of the IS, improvement in EH of insulin and normalization in beta-cell function at the various stages of the synthesis secretion process of insulin, explaining the improvement on glucose tolerance and on the glycemic control. The lack of improvement on the delay time highlights the characteristics of T2DM as a chronic, progressive and irreversible disease, once the surgical treatment contributes to the remission and not for the resolution of the disease. Understanding the mechanisms of the change in metabolism after BPD should help define the role of the gut in the physiopathology of T2DM, and help to develop new clinical and surgical approaches to treat the disease (AU)

• FAPESP's process: 08/07312-0 - Insulin secretory capacity in healthy patients, in obese, in obese type 2 diabetes and in obese type 2 diabetes undergoing bariatric surgery through the hyperglycemic clamp
• Grantee: Ana Carolina Junqueira Vasques
• Support Opportunities: Scholarships in Brazil - Doctorate