Type 2 diabetes (T2D) is characterized by reduction of β-cell mass and dysfunctional insulin secretion. Understanding β-cell phenotype changes as T2D progresses should help explain these abnormalities. The normal phenotype should differ from the state of overwork when β-cells compensate for insulin resistance to keep glucose levels normal. When only mild hyperglycaemia develops, β-cells are subjected to glucotoxicity. As hyperglycaemia becomes more severe, so does glucotoxicity. β-Cells in all four of these situations should have separate phenotypes. When assessing phenotype with gene expression, isolated islets have artefacts resulting from the trauma of isolation and hypoxia of islet cores. An advantage comes from laser capture microdissection (LCM), which obtains β-cell-rich tissue from pancreatic frozen sections. Valuable data can be obtained from animal models, but the real goal is human β-cells. Our experience with LCM and gene arrays on frozen pancreatic sections from cadaver donors with T2D and controls is described. Although valuable data was obtained, we predict that the approach of taking fresh samples at the time of surgery is an even greater opportunity to markedly advance our understanding of how β-cell phenotype evolves as T2D develops and progresses.
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