title: Characterization of collagenase blend enzymes for human islet transplantation.
abstract: BACKGROUND
  Efficient islet isolation represents a necessary requirement for successful islet transplantation as a treatment for type 1 diabetes. The choice of collagenase for pancreas digestion is critical for the isolation outcome, and Liberase is the most widely used enzyme, although large intra-batched variability in activity and efficiency has been observed.
  
  
  METHODS
  The aim of this study was to characterize Liberase components and their relative role in pancreas digestion. Liberase batches were characterized by microelectrophoresis.
  
  
  RESULTS
  By means of microelectrophoresis, we identified three main proteins each with different prevalences between batches. Two proteins were found to correspond to class I (CI) and one to class II (CII) collagenase. In a series of 163 islet isolations, we observed that the CII correlated with islet yield (P<0.001) and digestion time (P<0.001); additionally, CI directly correlated with purity (P=0.028). Finally, when CII and one of the CI isoforms were >50 percentile, 15 of 36 preparations were transplanted, with 27 of 127 transplanted in the other cases (P=0.013).
  
  
  CONCLUSIONS
  These results represent an important step toward the characterization of enzymes, with the final aim of identifying key components for a standardized product.
authors.affiliation: Unit of Cell Therapy for Type 1 Diabetes Mellitus, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Antonioli
authors.forename: Isabella
authors.initials: I
authors.lastname: Fermo
authors.forename: Silvia
authors.initials: S
authors.lastname: Cainarca
authors.forename: Simona
authors.initials: S
authors.lastname: Marzorati
authors.forename: Rita
authors.initials: R
authors.lastname: Nano
authors.forename: Michela
authors.initials: M
authors.lastname: Baldissera
authors.forename: Angela
authors.initials: A
authors.lastname: Bachi
authors.forename: Rita
authors.initials: R
authors.lastname: Paroni
authors.forename: Camillo
authors.initials: C
authors.lastname: Ricordi
authors.forename: Federico
authors.initials: F
authors.lastname: Bertuzzi
mesh_terms: D002469:Cell Separation / Q000379:methods; D017364:Collagenases / Q000032:analysis / Q000378:metabolism / Q000627:therapeutic use*; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D010179:Pancreas / Q000166:cytology; D013820:Thermolysin / Q000032:analysis / Q000378:metabolism / Q000627:therapeutic use*
chemical_list: D017364:Collagenases; C106635:Liberase; D013820:Thermolysin