title: Serine-protease inhibition during islet isolation increases islet yield from human pancreases with prolonged ischemia.
abstract: BACKGROUND
  Islet isolation from the pancreatic tissue matrix remains highly variable. Recent evidence suggests that intrinsic human pancreatic proteases, including trypsin, may inhibit effective collagenase enzymatic activity during islet isolation, thereby impairing the isolation success. In this study we have hypothesized that serine protease inhibition applied during pancreatic digestion, could improve yield and/or functional viability of islets isolated from human pancreases.
  
  
  METHODS
  Twelve organ donor pancreases with 12.9+/-0.6 hr cold storage (mean+/-SEM) were perfused via their ducts with Liberase-HI enzyme in the presence (n=6) or absence (n=6) of 0.4 mM Pefabloc. All were then gently dissociated and their purified islets separated with Ficoll density gradient centrifugation.
  
  
  RESULTS
  Donor-related factors (age, gender, cold storage time, body mass index, and pancreas weight) did not differ significantly between the two experimental groups. Pefabloc supplementation did not affect the digestion time, islets remaining trapped in exocrine tissue, or final islet purity. Islet recovery was increased in the Pefabloc-treated group (mean+/-SEM yield 323.8+/-80.8 x 10(3) islet equivalents vs. 130.8+/-13.6 x 10(3) islet equivalents, P<0.05). Cellular composition, DNA and insulin content, and insulin secretory activity of the isolated islets was similar.
  
  
  CONCLUSIONS
  Inhibition of intrinsic protease activity within pancreases after prolonged cold storage improves isolation of viable islets.
authors.affiliation: Surgical-Medical Research Institute, Department of Surgery, University of Alberta, Edmonton, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Lakey
authors.forename: L M
authors.initials: LM
authors.lastname: Helms
authors.forename: T
authors.initials: T
authors.lastname: Kin
authors.forename: G S
authors.initials: GS
authors.lastname: Korbutt
authors.forename: R V
authors.initials: RV
authors.lastname: Rajotte
authors.forename: A M
authors.initials: AM
authors.lastname: Shapiro
authors.forename: G L
authors.initials: GL
authors.lastname: Warnock
mesh_terms: D000293:Adolescent; D000328:Adult; D002102:Cadaver; D015925:Cryopreservation; D006801:Humans; D007515:Islets of Langerhans; D008875:Middle Aged; D010179:Pancreas; D015842:Serine Proteinase Inhibitors / Q000627:therapeutic use*; D013450:Sulfones / Q000627:therapeutic use*; D013997:Time Factors; D020858:Tissue and Organ Harvesting / Q000379:methods* / Q000592:standards*
chemical_list: D015842:Serine Proteinase Inhibitors; D013450:Sulfones; C002010:4-(2-aminoethyl)benzenesulfonylfluoride