RESUMO
BACKGROUND: Expression of the intermediate filament protein vimentin has been recently observed in the pancreatic islet ß- and α-cells of humans with type 2 diabetes mellitus. It was suggested that the presence of vimentin in endocrine cells may indicate islet tissue renewal, or potentially represent the dedifferentiation of endocrine cells, which could contribute to the onset of type 2 diabetes or islet cell dysfunction. AIM: To analyze the expression of vimentin in pancreatic ß- and α-cells of macrosomic infants of diabetic and nondiabetic mothers. SUBJECTS: Pancreatic samples of five macrosomic infants (gestational age 34-40weeks) from three diabetic and two nondiabetic mothers were compared to six control infants (32-40weeks, weight appropriate for gestational age) from normoglycemic mothers. METHODS: Pancreatic autopsy samples were examined by double immunofluorescent labeling with antibodies against vimentin and either insulin or glucagon. Alterations in the endocrine pancreas were measured using morphometric methods, then data were statistically analyzed. RESULTS: In the pancreatic islets of macrosomic infants from diabetic and nondiabetic mothers, we observed vimentin-positive cells, some of which simultaneously contained insulin or glucagon. We also quantitatively showed that the presence of such cells was associated with hypertrophy and hyperplasia of the islets, and with an increase in ß- and α-cell density. CONCLUSIONS: We speculate that the appearance of vimentin-positive islet cells may reflect induction of differentiation in response to the increased insulin demand, and vimentin may serve as an early marker of endocrine pancreas disorders.
