title: Engraftment of islets obtained by collagenase and Liberase in diabetic rats: a comparative study.
abstract: BACKGROUND
  Islet transplantation is an attractive solution for type I diabetes, but the results are at the present discouraging. Collagenase, the enzyme used to obtain islets for transplantation, presents interbatch variability and endotoxin contamination that induces inflammatory cytokine production. Liberase (Roche, Basel, Switzerland), a new mixture of purified enzymes, has the same composition in all batches and is endotoxin-free.
  
  
  OBJECTIVE
  To compare the engraftment of islets obtained using either enzyme in streptozotocin-induced diabetic rats.
  
  
  METHODS
  Collagenase- or Liberase-isolated islets were transplanted under the kidney capsule of diabetic rats. Collagenase islets restored glycemia and insulinemia in all animals at 24 hours, and both parameters were maintained in 45% of rats over 90 days; however, Liberase islets failed to reverse diabetes in all subjects.
  
  
  RESULTS
  In vitro experiments showed that Liberase islets did not maintain active insulin secretion. Cytotoxicity assays showed toxicity of Liberase to islets; both enzymes induced inflammatory cytokine production by macrophages.
  
  
  CONCLUSIONS
  In summary, in our model, Liberase is not a good substitute for collagenase as an islet-isolating reagent. A major effort and investment in developing enzymes for tissue dispersion is needed to improve the outcome of islet transplantation.
authors.affiliation: Division of Immunology, Germans Trias i Pujol University Hospital, Facultat de Medicina, Autonomous University of Barcelona, Carretera del Canyet s/n, 08916 Badalona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Vargas
authors.forename: J F
authors.initials: JF
authors.lastname: Julián
authors.forename: J F
authors.initials: JF
authors.lastname: Llamazares
authors.forename: F
authors.initials: F
authors.lastname: Garcia-Cuyàs
authors.forename: M
authors.initials: M
authors.lastname: Jiménez
authors.forename: R
authors.initials: R
authors.lastname: Pujol-Borrell
authors.forename: M
authors.initials: M
authors.lastname: Vives-Pi
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D016923:Cell Death / Q000187:drug effects; D017364:Collagenases / Q000378:metabolism / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000601:surgery*; D004731:Endotoxins / Q000032:analysis; D006085:Graft Survival; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007375:Interleukin-1 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D007515:Islets of Langerhans / Q000502:physiology; D016381:Islets of Langerhans Transplantation; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013048:Specimen Handling; D013820:Thermolysin / Q000378:metabolism / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D001786:Blood Glucose; D004731:Endotoxins; D007328:Insulin; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D017364:Collagenases; C106635:Liberase; D013820:Thermolysin