title: Simplified method to isolate highly pure canine pancreatic islets.
abstract: OBJECTIVE
  The canine model has been used extensively to improve the human pancreatic islet isolation technique. At the functional level, dog islets show high similarity to human islets and thus can be a helpful tool for islet research. We describe and compare 2 manual isolation methods, M1 (initial) and M2 (modified), and analyze the variables associated with the outcomes, including islet yield, purity, and glucose-stimulated insulin secretion (GSIS).
  
  
  METHODS
  Male mongrel dogs were used in the study. M2 (n = 7) included higher collagenase concentration, shorter digestion time, faster shaking speed, colder purification temperature, and higher differential density gradient than M1 (n = 7).
  
  
  RESULTS
  Islet yield was similar between methods (3111.0 ± 309.1 and 3155.8 ± 644.5 islets/g, M1 and M2, respectively; P = 0.951). Pancreas weight and purity together were directly associated with the yield (adjusted R(2) = 0.61; P = 0.002). Purity was considerably improved with M2 (96.7% ± 1.2% vs 75.0% ± 6.3%; P = 0.006). M2 improved GSIS (P = 0.021). Independently, digestion time was inversely associated with GSIS.
  
  
  CONCLUSIONS
  We describe an isolation method (M2) to obtain a highly pure yield of dog islets with adequate β-cell glucose responsiveness. The isolation variables associated with the outcomes in our canine model confirm previous reports in other species, including humans.
authors.affiliation: Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA. owoolcot@usc.edu
authors.forename: Orison O
authors.initials: OO
authors.lastname: Woolcott
authors.forename: Richard N
authors.initials: RN
authors.lastname: Bergman
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Richey
authors.forename: Erlinda L
authors.initials: EL
authors.lastname: Kirkman
authors.forename: L Nicole
authors.initials: LN
authors.lastname: Harrison
authors.forename: Viorica
authors.initials: V
authors.lastname: Ionut
authors.forename: Maya
authors.initials: M
authors.lastname: Lottati
authors.forename: Dan
authors.initials: D
authors.lastname: Zheng
authors.forename: Isabel R
authors.initials: IR
authors.lastname: Hsu
authors.forename: Darko
authors.initials: D
authors.lastname: Stefanovski
authors.forename: Morvarid
authors.initials: M
authors.lastname: Kabir
authors.forename: Stella P
authors.initials: SP
authors.lastname: Kim
authors.forename: Karyn J
authors.initials: KJ
authors.lastname: Catalano
authors.forename: Jenny D
authors.initials: JD
authors.lastname: Chiu
authors.forename: Robert H
authors.initials: RH
authors.lastname: Chow
mesh_terms: D000818:Animals; D002470:Cell Survival; D004285:Dogs; D005452:Fluoresceins / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008856:Microscopy, Fluorescence; D015203:Reproducibility of Results; D046509:Tissue Culture Techniques / Q000379:methods
chemical_list: D005452:Fluoresceins; D007328:Insulin; D005947:Glucose; C018506:diacetylfluorescein