Short-term culture with the caspase inhibitor z-VAD.fmk reduces beta cell apoptosis in transplanted islets and improves the metabolic outcome of the graft.
In the initial days after transplantation islets are particularly vulnerable and show increased apoptosis and necrosis. We have studied the effects of caspase inhibition on this early beta cell death in syngeneically transplanted islets. Streptozotocin-diabetic C57BL/6 mice were transplanted with 150 syngeneic islets, an insufficient mass to restore normoglycemia, preincubated with or without the pan-caspase inhibitor z-VAD. fmk 2 h before transplantation. Beta cell apoptosis was increased in control islets on day 3 after transplantation (0.28 +/- 0.02%) compared with freshly isolated islets (0.08 +/- 0.02%, p < 0.001), and was partially reduced in transplanted islets preincubated with z-VAD.fmk 200 microM (0.14 +/- 0.02%, p = 0.003) or with z-VAD.fmk 500 microM (0.17 +/- 0.01%, p = 0.012), but not with a lower z-VAD.fmk (100 microM) concentration. Diabetic mice transplanted with islets preincubated with z-VAD.fmk 500 microM showed an improved metabolic evolution compared with control and z-VAD.fmk 200 microM groups. The z-VAD.fmk 500 microM group showed an overall lower blood glucose after transplantation (p = 0.02), and at the end of the study blood glucose values were reduced compared with transplantation day (15.7 +/- 3.6 vs. 32.5 +/- 0.5 mmol/L, p = 0.001). In contrast, blood glucose was not significantly changed in control and z-VAD.fmk 200 microM groups. Four weeks after transplantation beta cell mass was higher in z-VAD.fmk 500 microM group (0.15 +/- 0.02 mg) than in the control group (0.10 +/- 0.02 mg) (p = 0.043). In summary, the treatment of freshly isolated islets with the caspase inhibitor z-VAD.fmk reduced the subsequent apoptosis of the islets once they were transplanted and improved the outcome of the graft.
Montolio
Marta
M
Laboratory of Diabetes and Experimental Endocrinology, Endocrine Unit, IDIBELL-Hospital Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.
Téllez
Noèlia
N
Biarnés
Montserrat
M
Soler
Joan
J
Montanya
Eduard
E
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000601:surgery / Q000628:therapy; D006085:Graft Survival / Q000187:drug effects*; D007515:Islets of Langerhans / Q000187:drug effects* / Q000473:pathology; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013997:Time Factors; D046509:Tissue Culture Techniques
D000590:Amino Acid Chloromethyl Ketones; D001786:Blood Glucose; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone