Rowley 2017 Thesis

From Bioblast
Publications in the MiPMap
Rowley TJ (2017) The effect of cocoa flavanols on Ξ²-cell mass and function. Master's Thesis p131.

Β» Open Access

Rowley TJ (2017) Master's Thesis

Abstract: A hallmark of type 2 diabetes (T2D) is Ξ²-cell dysfunction and the eventual loss of functional Ξ²-cell mass. Therefore, mechanisms that improve or preserve Ξ²-cell function could be used to improve the quality of life of individuals with T2D. Studies have shown that monomeric, oligomeric and polymeric cocoa flavanols have different effects on obesity, insulin resistance and glucose tolerance. We hypothesized that these cocoa flavanols may have beneficial effects on Ξ²-cell function. INS-1 832/13 derived Ξ²-cells and primary rat islets cultured with a monomeric catechin-rich cocoa flavanol fraction demonstrated enhanced glucose-stimulated insulin secretion, while cells cultured with total cocoa extract, oligomeric, or polymeric procyanidin-rich fractions demonstrated no improvement. The increased glucose-stimulated insulin secretion in the presence of the monomeric catechin-rich fraction corresponded with enhanced mitochondrial respiration, suggesting improvements in Ξ²-cell fuel utilization. Mitochondrial complex III, IV and V components were upregulated after culture with the monomer-rich fraction, corresponding with increased cellular ATP production. The monomer-rich fraction improved cellular redox state and increased glutathione concentration, which corresponds with Nrf2 nuclear localization and expression of Nrf2 target genes, including NRF-1 and GABPA, essential genes for increasing mitochondrial function. We propose a model by which monomeric cocoa catechins improve the cellular redox state, resulting in Nrf2 nuclear migration and upregulation of genes critical for mitochondrial respiration, and, ultimately, enhanced glucose-stimulated insulin secretion and Ξ²-cell function. These results suggest a mechanism by which monomeric cocoa catechins exert their effects as an effective complementary strategy to benefit T2D patients. β€’ Keywords: Cocoa, Ξ²-cell, Catechin, Insulin secretion, Mitochondrial respiration, Nrf2 β€’ Bioblast editor: Kandolf G β€’ O2k-Network Lab: US UT Provo Bikman BT

Labels: MiParea: Exercise physiology;nutrition;life style, Pharmacology;toxicology  Pathology: Diabetes, Obesity 

Organism: Rat  Tissue;cell: Islet cell;pancreas;thymus  Preparation: Permeabilized cells  Enzyme: Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase 

Coupling state: OXPHOS, ET  Pathway: N, NS, ROX  HRR: Oxygraph-2k 

Labels, 2017-12 

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