Efficiency of in vitro adenoviral-mediated gene transfer in isolated pancreatic islets and effect on in vivo and in vitro islet function
摘要
We investigated the efficiency and functional consequences of adenoviral-mediated gene transfer into murine pancreatic islets with a recombinant adenovirus encoding for the E. Coli β-Gal reporter gene. Over 90%of islets were transduced with 4.105 pfu/islet. Analysis of frozen islet sections showed that transduced cells were always located at the periphery of islets. Transduced and control islets were functionnally assessed in vitro by static incubation, and showed a similar insulin secretion. Viability was assessed in vivo by transplantation of syngeneic islets in STZ- diabetic recipients. All mice receiving either transduced (n=5) or control (n=7) islets recovered normoglycemia at 4 ± 4.1 vs 3.8 ± 2.9 days and remained euglycemic over 120 days. Staining of grafted transduced islets with X-Gal showed that β-Gal expression was lost in the tissues between day 30 and 50. Control (n=10) or transduced islets (n=5) transplanted in an allogeneic combination (DBA2 into C57BL/6) showed equivalent kinetics of glycemia normalisation and rejection (16.2 ± 4 vs 16.3 ± 4 days). Cellular expression of adenoviral proteins following Ad transduction is known to induce host immunisation and local inflammation. However, and in contrast to 293 cells, transduced islets did not express detectable levels of adenoviral hexon proteins. Nevertheless, mice grafted with syngeneic transduced islets showed a moderate leukocyte infiltrate and weak levels of antiadenovirus antibodies. In summary, Ad-mediated gene transfer into islets was highly efficient and did not impair their function. In spite of a transient expression, Ad-mediated gene transfer in islets could be an effective tool for modifying the local environment early after transplantation with antiinflammatory or immunosuppressive molecules.