title: The ratio between collagenase class I and class II influences the efficient islet release from the rat pancreas.
abstract: BACKGROUND
  Previous studies indicated different roles of collagenase class I, class II and neutral protease in the enzymatic islet release from pancreatic tissue. Because no information has been available, this study was aimed to investigate the isolation efficiency of different ratios between collagenase class II and I (C-ratio) in the rat pancreas serving as model for the human pancreas without being restricted by the large variability observed in human donors.
  
  
  METHODS
  Rat pancreata were digested using a marginal neutral protease activity and 20 PZ-U of purified collagenase classes recombined to create a C-ratio of 0.5, 1.0, or 1.5. Collagenase efficiency was evaluated in terms of isolation outcome and posttransplantation function in diabetic nude mice.
  
  
  RESULTS
  The highest yield of freshly isolated islets was obtained using a C-ratio of 1.0. Purity and fragmentation of freshly isolated islets were not influenced by the C-ratio. After 24-hr culture performed for quality assessment, a marginal but significant reduction of viability was observed in islets isolated by means of a C-ratio of 0.5 and 1.5. Islet in vitro and posttransplantation function revealed no negative effect mediated by different C-ratios.
  
  
  CONCLUSIONS
  The present study demonstrates that the C-ratio is of significant relevance for the outcome after enzymatic rat islet isolation. The data indicate further that purified collagenase class I or class II does not damage islet tissue even if used in excess. The present study can serve as a start for subsequent experiments in the human pancreas.
authors.affiliation: Department of Oncology, Radiology and Clinical Immunology, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Heide
authors.initials: H
authors.lastname: Brandhorst
authors.forename: Nicole
authors.initials: N
authors.lastname: Raemsch-Guenther
authors.forename: Christian
authors.initials: C
authors.lastname: Raemsch
authors.forename: Olaf
authors.initials: O
authors.lastname: Friedrich
authors.forename: Silke
authors.initials: S
authors.lastname: Huettler
authors.forename: Manfred
authors.initials: M
authors.lastname: Kurfuerst
authors.forename: Olle
authors.initials: O
authors.lastname: Korsgren
authors.forename: Daniel
authors.initials: D
authors.lastname: Brandhorst
mesh_terms: D000818:Animals; D002469:Cell Separation; D002851:Chromatography, High Pressure Liquid; D017364:Collagenases / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D017364:Collagenases