title: Co-expression of vascular endothelial growth factor and interleukin-1 receptor antagonist improves human islet survival and function.
abstract: OBJECTIVE
  Ex vivo gene therapy approaches can improve the outcome of islet transplantation for treating type I diabetes. We have previously shown the improvement in islet function and vascularization following ex vivo transfection for human vascular endothelial growth factor (hVEGF) gene expression. In this study, we tested the hypothesis that co-expression of two genes, which target different challenges faced by islets post-transplantation, supplement each other to improve the survival and function of islets. We determined whether there is an additive effect of hVEGF and human interleukin-1 receptor antagonist (hIL-1Ra) gene expression in human islets.
  
  
  METHODS
  Human islets were co-infected with adenoviral vectors encoding hVEGF and hIL-1Ra. Islets were then incubated with a cocktail of inflammatory cytokines (IL-1beta+TNFalpha+IFNgamma), and islet viability and function were determined. In vivo function was evaluated by transplanting islets under the kidney capsules of streptozotocin-induced non-obese diabetic severe combined immunodeficient (NOD-SCID) mice.
  
  
  RESULTS
  Infection of human islets with Adv-hVEGF and/or Adv-hIL-1Ra inhibited expression of inducible nitric oxide synthase (iNOS), decreased the production of nitric oxide (NO), and prevented the loss of in vitro glucose-stimulated insulin response and viability. Moreover, co-expression of hVEGF and hIL-1Ra reduced the blood glucose level of mice, and increased the level of blood insulin and c-peptide upon glucose challenge.
  
  
  CONCLUSIONS
  Our results indicated that co-expression of genes that target different insults to transplanted islets can improve the outcome of islet transplantation better than either gene alone.
authors.affiliation: Department of Pharmaceutical Sciences, University of Tennesee Health Science Center, 26 S Dunlap St., Feurt Bldg RM 413, Memphis, Tennessee 38163, USA.
authors.forename: Ajit S
authors.initials: AS
authors.lastname: Narang
authors.forename: Omaima
authors.initials: O
authors.lastname: Sabek
authors.forename: Ahmed O
authors.initials: AO
authors.lastname: Gaber
authors.forename: Ram I
authors.initials: RI
authors.lastname: Mahato
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D015870:Gene Expression / Q000502:physiology; D005822:Genetic Vectors; D006801:Humans; D007328:Insulin / Q000378:metabolism; D053590:Interleukin 1 Receptor Antagonist Protein; D007515:Islets of Langerhans / Q000166:cytology / Q000502:physiology*; D016381:Islets of Langerhans Transplantation; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D009573:Nitrites / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D009924:Organ Culture Techniques; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology
chemical_list: C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D007328:Insulin; D053590:Interleukin 1 Receptor Antagonist Protein; D009573:Nitrites; D009707:Nucleosomes; D012795:Sialoglycoproteins; D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D020169:Caspases