Blood mediated reaction following intraportal islet allograft in pigs.

Study aim: Intraportal islet allograft appears to be one of the promising t reatments for type I diabetes. However, many limiting factors persist. An a ctivation of the coagulation cascade upon contact with islets, has been rep orted recently in vitro and could play a crucial role in a non specific inf lammatory reaction and favour the specific immune reaction. The aim of this experimental study was to confirm in vivo this activation of the coagulati on cascade. Material and methods: An allogenic islets preparation or a material control (inert microbeads) was injected intraportally, in Large White pigs (n=26), associated with or without an anticoagulant treatment (heparin). Systemic markers of haemostasis were measured in pigs for 72 hours following injecti on of the studied material. Results: The thrombin-antithrombin complex increased and platelet count dec reased in groups receiving preparation of islets, both indicators of an act ivation of the coagulation cascade. This activation was proportional to the injected volume and was partially attenuated by heparin. No activation was observed in pigs receiving the material control. Conclusion: The activation of the coagulation cascade and the non specific inflammatory reaction could be one of the obstacles to the success of the i slet allografts. The use of anticoagulant and anti-inflammatory molecules c ould potentially allow an improvement of the present results of islet allog raft. (C) 2001 Editions scientifiques et medicales Elsevier SAS.