title: Young porcine endocrine pancreatic islets cultured in fibrin show improved resistance toward hydrogen peroxide.
abstract: OBJECTIVE
  To study the protective effect of a fibrin scaffold toward embedded young porcine endocrine pancreatic islets from hydrogen peroxide within the context of islet encapsulation in transplantation.
  
  
  METHODS
  After isolation and in vitro maturation, groups of 200 young porcine islet equivalents (IEQ) were embedded in a 200 µL fibrin gel and exposed to 2 concentrations (10 and 100 µM) of hydrogen peroxide (H2O2) to investigate the ability of fibrin to protect islets against apoptotic stimuli. As a control, young porcine islets were seeded in tissue culture polystyrene (TCPS) well plates and exposed to the same H2O2 concentrations. Islet integrity, viability and function were then investigated.
  
  
  RESULTS
  Morphologically, the integrity of islets embedded in fibrin gels was better preserved compared with that of islets cultured in TCPS plates, when exposed to H2O2. Immunofluorescence staining showed that insulin and glucagon expression was higher in islets cultured in fibrin. Overall, H2O2 incubation led to decreased insulin and glucagon expression. A TUNEL assay revealed elevated numbers of apoptotic cells for islets cultured in TCPS plates when compared with those embedded in fibrin. Islets cultured in TCPS plates and exposed to H2O2 had diminished ability to secrete insulin in response to glucose stimulation, whereas islets embedded in fibrin maintained their glucose responsiveness. Insulin trapped in fibrin was extracted and quantified, revealing insulin in the extract.
  
  
  CONCLUSIONS
  Fibrin has a protective effect on young porcine endocrine pancreatic islets exposed to hydrogen peroxide.
authors.affiliation: Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke; Department of Chemical and Biotechnological Engineering; Université de Sherbrooke; Sherbrooke, Québec, Canada; Research Centre on Aging; Institut universitaire de gériatrie de Sherbrooke; Sherbrooke, Québec, Canada.
authors.forename: Carina
authors.initials: C
authors.lastname: Kuehn
authors.affiliation: Department of Surgery and Biomedical Engineering; University of California, Irvine; Irvine, CA USA.
authors.forename: Jonathan R T
authors.initials: JR
authors.lastname: Lakey
authors.affiliation: Department of Surgery and Biomedical Engineering; University of California, Irvine; Irvine, CA USA.
authors.forename: Morgan W
authors.initials: MW
authors.lastname: Lamb
authors.affiliation: Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke; Department of Chemical and Biotechnological Engineering; Université de Sherbrooke; Sherbrooke, Québec, Canada; Research Centre on Aging; Institut universitaire de gériatrie de Sherbrooke; Sherbrooke, Québec, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Vermette
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival; D003470:Culture Media; D005337:Fibrin / Q000494:pharmacology*; D005782:Gels; D005934:Glucagon / Q000032:analysis; D005947:Glucose / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007328:Insulin / Q000032:analysis / Q000378:metabolism; D000078790:Insulin Secretion; D039482:Integrin alpha5 / Q000032:analysis; D007515:Islets of Langerhans / Q000033:anatomy & histology / Q000737:chemistry* / Q000187:drug effects* / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000379:methods; D016877:Oxidants / Q000494:pharmacology*; D013552:Swine; D054457:Tissue Scaffolds
chemical_list: D003470:Culture Media; D005782:Gels; D007328:Insulin; D039482:Integrin alpha5; D016877:Oxidants; D005337:Fibrin; D005934:Glucagon; D006861:Hydrogen Peroxide; D005947:Glucose
keywords: encapsulation; endocrine pancreatic islet culture; extracellular matrix; fibrin; hydrogen peroxide; porcine pancreatic islets