Islet Engraftment and Revascularization in Clinical and Experimental Transplantation

• Background:Proper revascularization after transplantation is assumed to be crucial forappropriate islet graft function.Methods:We developed a novel non-invasive imagingmethod, based on adenoviral transduction of islets with a hypoxia responsive reporter gene,for continuous in vivo monitoring of hypoxia in islet grafts in a mouse model. In addition,morphological data was obtained from a deceased patient previously subject to intraportaltransplantation.Results:We detected only transient hypoxia in a minority of the animalstransplanted. Importantly, a clear response to hypoxia was observed in vitro after removal ofthe islet-grafts on day twenty-eight after transplantation. Also, the morphological data fromthe deceased patient demonstrated an extensive revascularization of the transplanted islets. Infact, no differences could be seen between native, in pancreas biopsies taken prior to isletisolation, and transplanted islets regarding the number, distribution and shape of the bloodvessels. However, fewer small islets (diameter <39μm) were found in the liver compared to those found in native pancreases. Notably, an absolute majority of the transplanted islets were found remaining within the venous lumen, in direct contact with the vessel wall.Conclusions:In conclusion results presented show less pronounced islet graft hypoxia after subcapsulartransplantation than previously reported using more invasive methods. Also, formation of anextensive intra-islet capillary network, similar to that seen in native islets in the pancreas, wasseen after clinical islet transplantation.

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)