RT Journal Article
SR Electronic
T1 Prolonged Exposure to Free Fatty Acids Has Cytostatic and Pro-Apoptotic Effects on Human Pancreatic Islets
JF Diabetes
JO Diabetes
FD American Diabetes Association
SP 1437
OP 1442
DO 10.2337/diabetes.51.5.1437
VO 51
IS 5
A1 Lupi, Roberto
A1 Dotta, Francesco
A1 Marselli, Lorella
A1 Del Guerra, Silvia
A1 Masini, Matilde
A1 Santangelo, Carmela
A1 Patané, Giovanni
A1 Boggi, Ugo
A1 Piro, Salvatore
A1 Anello, Marcello
A1 Bergamini, Ettore
A1 Mosca, Franco
A1 Di Mario, Umberto
A1 Del Prato, Stefano
A1 Marchetti, Piero
YR 2002
UL http://diabetes.diabetesjournals.org/content/51/5/1437.abstract
AB In an effort to better understand the phenomenon of lipotoxicity in human β-cells, we evaluated the effects of 48-h preculture with 1.0 or 2.0 mmol/l free fatty acid (FFA) (2:1 oleate to palmitate) on the function and survival of isolated human islets and investigated some of the possible mechanisms. Compared with control islets, triglyceride content was significantly increased and insulin content and glucose-stimulated insulin release were significantly reduced in islets precultured with increased FFA concentrations. These changes were accompanied by a significant reduction of glucose utilization and oxidation. By cell death detection techniques, it was observed that exposure to FFAs induced a significant increase of the amount of dead cells. Electron microscopy showed the involvement of β-cells, with morphological appearance compatible with the presence of apoptotic phenomena. FFA-induced islet cell death was blocked by inhibition of upstream caspases and partially prevented by inhibiton of ceramide synthesis or serine protease activity, whereas inhibition of nitric oxide synthesis had no effect. RT-PCR studies revealed no major change of iNOS and Bax mRNA expression and a marked decrease of Bcl-2 mRNA expression in the islets cultured with FFA. Thus, prolonged exposure to FFAs has cytostatic and pro-apoptotic effects on human pancreatic β-cells. The cytostatic action is likely to be due to the FFA-induced reduction of intraislet glucose metabolism, and the proapoptotic effects are mostly caspase mediated, partially dependent on ceramide pathway, and possibly Bcl-2 regulated.