Deterioration and variability of highly purified collagenase blends used in clinical islet isolation

Transplantation. 2007 Oct 27;84(8):997-1002. doi: 10.1097/


Background: The quality and stability of enzyme blends used in islet cell processing are critical for successful human islet isolation. A wide variability in enzymatic activity among lots of Liberase HI has been reported. This study examines the interlot and intralot variability of Liberase HI and the over-time deterioration of enzyme quality based on the analysis of islet isolation outcomes.

Methods: The data of 169 human isolations processed for clinical islet transplantation, using five different lots of Liberase HI, were retrospectively analyzed. Inter- and intralot variables in the islet isolation were assessed over a 15-month period.

Results: The analysis revealed significant interlot differences in the digestion time, prepurification islet counts, percent recovery, viability, and glucose stimulation insulin index. Moreover, a significant decrease in the pre- and postpurification islet yield per pancreas weight (IEQ/g) in isolations processed by two different enzyme lots used over a 15-month period was observed, suggesting a progressive deterioration of enzyme quality.

Conclusions: Our data demonstrate a significant lot-to-lot related variability in islet isolation outcomes. In addition, the over-time decline in isolation outcomes processed using a single enzyme lot was observed even when the enzyme blends were used within the expiration dating specified by the manufacturer.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Separation*
  • Cell Survival
  • Collagenases / chemistry
  • Collagenases / isolation & purification
  • Collagenases / standards*
  • Female
  • Glucose / pharmacology
  • Humans
  • Islets of Langerhans / chemistry
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / physiology*
  • Islets of Langerhans Transplantation*
  • Male
  • Thermolysin / chemistry
  • Thermolysin / isolation & purification
  • Thermolysin / standards*
  • Tissue Donors
  • Tissue and Organ Harvesting*
  • Treatment Outcome


  • Collagenases
  • Liberase
  • Thermolysin
  • Glucose