title: Adenoviral gene transfer of erythropoietin confers cytoprotection to isolated pancreatic islets.
abstract: BACKGROUND
  The transfer of cytoprotective genes to isolated pancreatic islets may contribute to their enhanced survival in the transplant setting. Our laboratory established the expression of functional erythropoietin (EPO) receptors throughout pancreatic islets. Because EPO is a cytokine that promotes survival, we examined whether adenovirus-mediated gene transfer of EPO would result in cytoprotection of human pancreatic islets in culture and in the transplant setting.
  
  
  METHODS
  Isolated human islets were transduced using an adenoviral vector coding for human EPO or green fluorescent protein. Comparison of cell death in culture was measured using annexin V-phycoerythrin and propidium iodide. Transplantation of transduced islets into diabetic nude mice was used to assess the effect of EPO on islet function and in vivo survival.
  
  
  RESULTS
  Adenoviral delivery of EPO to pancreatic islets resulted in high-level EPO synthesis and secretion, which did not affect islet function in vitro or in vivo. Islets transduced with EPO were protected from apoptosis in culture and were at a functional advantage in vivo when compared with islets transduced with green fluorescent protein or untransduced islets. The high level of EPO had a negative effect on the blood chemistry of the animals that underwent transplantation.
  
  
  CONCLUSIONS
  Overexpression of EPO protects islets from destruction and does not compromise islet function. Genetic engineering with EPO may be a viable approach for improving islet survival and engraftment in the transplant setting, but regulation of the gene's expression will be an important prerequisite to this strategy.
authors.affiliation: Diabetes Research Institute, University Of Miami School of Medicine, Miami, FL 33136, USA. Efenjves@ miami.edu
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Fenjves
authors.forename: M Sofia
authors.initials: MS
authors.lastname: Ochoa
authors.forename: Carlota
authors.initials: C
authors.lastname: Gay-Rabinstein
authors.forename: R Damaris
authors.initials: RD
authors.lastname: Molano
authors.forename: Antonello
authors.initials: A
authors.lastname: Pileggi
authors.forename: Armando J
authors.initials: AJ
authors.lastname: Mendez
authors.forename: Luca
authors.initials: L
authors.lastname: Inverardi
authors.forename: Camillo
authors.initials: C
authors.lastname: Ricordi
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D001769:Blood / Q000187:drug effects; D019610:Cytoprotection; D004921:Erythropoietin / Q000009:adverse effects / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects; D051379:Mice; D008819:Mice, Nude
chemical_list: D007328:Insulin; D004921:Erythropoietin