title: Clostripain, the Missing Link in the Enzyme Blend for Efficient Human Islet Isolation.
abstract: Effective digestive enzymes are crucial for successful islet isolation. Supplemental proteases are essential as they synergize with collagenase for effective pancreas digestion. The presence of tryptic-like activity has been implicated in efficient enzyme blends and the present study aimed to evaluate if addition of clostripain, an enzyme with tryptic-like activity, could improve efficacy of the islet isolation procedure.
  
  
  METHODS
  Clostripain was added to the enzyme blend just before pancreas perfusion. Islets were isolated per standard method and numerous isolation parameters, islet quality control, and the number of isolations fulfilling standard transplantation criteria were evaluated. Two control organs per clostripain organ were chosen by blindly matching against body mass index, cold ischemia time, hemoglobin A1c, donor sex, and donor age.
  
  
  RESULTS
  There were no differences in pancreas weight, dissection time, digestion time, harvest time, percent digested pancreas, or total pellet volume before islet purification between control or clostripain pancreases. Glucose-stimulated insulin release results were similar between groups. Total isolation islet equivalents, purified tissue volume and islet equivalents/g pancreas as well as fulfillment of transplantation criteria favored clostripain processed pancreases.
  
  
  CONCLUSIONS
  The addition of clostripain to the enzyme blend soundly improved islet yields and transplantation rates. It gently aided pancreas digestion and maintained proper islet functionality. The addition of clostripain to the enzyme blend has now been implemented into standard isolation protocols at the isolation centers in Uppsala and in Oslo.
authors: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
authors: Magnus
authors: M
authors: Ståhle
authors: Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors: Aksel
authors: A
authors: Foss
authors: Department of Transplantation, University Hospital, Gothenburg, Sweden.
authors: Bengt
authors: B
authors: Gustafsson
authors: Department of Transplantation and Liver Surgery, Helsinki University Hospital, Helsinki, Finland.
authors: Marko
authors: M
authors: Lempinen
authors: Division of Transplantation Surgery, CLINTEC, Karolinska Institute, Stockholm, Sweden.
authors: Torbjörn
authors: T
authors: Lundgren
authors: Transplantation Unit, Department of Surgery, Skåne University Hospital, Malmö, Sweden.
authors: Ehab
authors: E
authors: Rafael
authors: Division of Transplantation Surgery, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden.
authors: Gunnar
authors: G
authors: Tufveson
authors: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
authors: Olle
authors: O
authors: Korsgren
authors: Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
authors: Andrew
authors: A
authors: Friberg