Dynamic Change of β to α Ratio in Islets of Chinese People With Prediabetes and Type 2 Diabetes Mellitus.

OBJECTIVES: The present study aimed to investigate the dynamic change of α cells and β cells, and their ratios in prediabetes and type 2 diabetes in the Chinese population. METHODS: Pancreata from 27 nondiabetic (ND), 8 prediabetic (PreD), and 19 type 2 diabetic (T2D) organ donors were subjected to immunofluorescence staining with insulin and glucagon. RESULTS: The β to α ratio in islets (β/α) in PreD was significantly higher than that in ND, resulting from an increase of β cells and a decrease of α cells per islet, but that in T2D was significantly lower than that in ND, resulting from a decrease of β cells and an increase of α cells per islet. The β-cell percentage and β/α ratio positively correlated and α-cell percentage negatively correlated with HbA1c (glycated hemoglobin) in ND and PreD, but these correlations disappeared when T2D subjects were included. CONCLUSIONS: The islet β to α ratio increased in PreD individuals because of a relative α-cell loss and β-cell compensation and decreased after T2D onset because of both β-cell loss and α-cell reexpansion.