title: Long-term function of islets encapsulated in a redesigned alginate microcapsule construct in omentum pouches of immune-competent diabetic rats.
abstract: OBJECTIVE
  Our study aim was to determine encapsulated islet graft viability in an omentum pouch and the effect of fibroblast growth factor 1 (FGF-1) released from our redesigned alginate microcapsules on the function of the graft.
  
  
  METHODS
  Isolated rat islets were encapsulated in an inner core made with 1.5% low-viscosity-high-mannuronic-acid alginate followed by an external layer made with 1.25% low-viscosity high-guluronic acid alginate with or without FGF-1, in microcapsules measuring 300 to 400 µm in diameter. The 2 alginate layers were separated by a perm-selective membrane made with 0.1% poly-L-ornithine, and the inner low-viscosity-high-mannuronic-acid core was partially chelated using 55 mM sodium citrate for 2 minutes.
  
  
  RESULTS
  A marginal mass of encapsulated islet allografts (∼2000 islets/kg) in streptozotocin-diabetic Lewis rats caused significant reduction in blood glucose levels similar to the effect observed with encapsulated islet isografts. Transplantation of alloislets coencapsulated with FGF-1 did not result in better glycemic control, but induced greater body weight maintenance in transplant recipients compared with those that received only alloislets. Histological examination of the retrieved tissue demonstrated morphologically and functionally intact islets in the microcapsules, with no signs of fibrosis.
  
  
  CONCLUSIONS
  We conclude that the omentum is a viable site for encapsulated islet transplantation.
authors.affiliation: From the *Wake Forest Institute for Regenerative Medicine, †Virginia Tech-Wake Forest University School of Biomedical Engineering & Sciences, and ‡Department of Surgery, Wake Forest School of Medicine, Winston-Salem, NC; and §Department of Biomedical Engineering, Illinois Institute of Technology, Chicago; and ∥Research Service, Hines Veterans Administration Hospital, Hines, IL.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Pareta
authors.forename: John P
authors.initials: JP
authors.lastname: McQuilling
authors.forename: Sivanandane
authors.initials: S
authors.lastname: Sittadjody
authors.forename: Randy
authors.initials: R
authors.lastname: Jenkins
authors.forename: Stephen
authors.initials: S
authors.lastname: Bowden
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Orlando
authors.forename: Alan C
authors.initials: AC
authors.lastname: Farney
authors.forename: Eric M
authors.initials: EM
authors.lastname: Brey
authors.forename: Emmanuel C
authors.initials: EC
authors.lastname: Opara
mesh_terms: D000464:Alginates; D043925:Angiogenesis Inducing Agents / Q000008:administration & dosage; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002470:Cell Survival; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000276:immunology / Q000601:surgery*; D016220:Fibroblast Growth Factor 1 / Q000008:administration & dosage; D020723:Glucuronic Acid; D006085:Graft Survival; D006603:Hexuronic Acids; D007121:Immunocompetence; D007515:Islets of Langerhans / Q000098:blood supply / Q000276:immunology / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D018919:Neovascularization, Physiologic; D009852:Omentum / Q000098:blood supply / Q000601:surgery*; D011917:Rats, Inbred Lew; D017208:Rats, Wistar; D013997:Time Factors; D054457:Tissue Scaffolds
chemical_list: D000464:Alginates; D043925:Angiogenesis Inducing Agents; D001786:Blood Glucose; D006603:Hexuronic Acids; D016220:Fibroblast Growth Factor 1; D020723:Glucuronic Acid