Assessment of a novel two-component enzyme preparation for human islet isolation and transplantation

Transplantation. 2005 Jan 15;79(1):91-7. doi: 10.1097/


Background: Biologic characteristics of enzyme products used for islet isolation are critical for the success of islet transplantation. In particular, lot-to-lot variability significantly affects the yields of the isolation procedure. In this study, we have evaluated a new enzyme preparation in which highly purified collagenase can be blended with separately supplied neutral protease in a predetermined ratio.

Methods: We compared the results of human-islet isolations performed either with Collagenase NB1 supplemented with Neutral Protease NB (group I, n=9) or with Liberase (group II, n=9).

Results: Endotoxin contents of the enzyme preparations were lower in group I. Total islet yields were similar in both groups, but islet equivalents per gram of pancreas was higher in group I (4,020+/-1,240 vs. 2,360+/-1,350; P<0.05). Islet morphology was improved in group I with significantly higher proportion of free and intact islets (71+/-9% vs. 52+/-14%; P<0.01). In vitro function was improved and apoptosis rate was lower in group I.

Conclusions: This new enzyme blend was as efficient as Liberase in terms of islet yields and showed improvements in islet morphology, viability, and in vitro function. The possibility to control lot-to-lot variability and the low endotoxin contents make Collagenase NB1 a promising product for human-islet isolation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Separation / methods*
  • Cell Survival
  • Collagenases / pharmacology*
  • Humans
  • Islets of Langerhans / cytology*
  • Islets of Langerhans Transplantation / methods*
  • Middle Aged
  • Thermolysin / pharmacology*


  • Collagenases
  • Liberase
  • Thermolysin