Related Experiment Video
Updated: Jun 25, 2026
Pancreatic Islet Isolation and Purification from Lewis Rats Using Enzymatic Digestion and Density-Gradient Separation
Published on: April 3, 2026
The importance of tryptic-like activity in purified enzyme blends for efficient islet isolation
Heide Brandhorst1, Andrew Friberg, Helena H Andersson
1Department of Oncology, Radiology and Clinical Immunology, Uppsala University Hospital, Uppsala, Sweden. Daniel.Brandhorst@klinimm.uu.se
Background:
The isolation of islets from the human pancreas critically depends on an efficient enzyme blend. Previous studies have solely focused on the presence of collagenase and neutral protease/thermolysin. Despite improved characterization of these components, the lot-related variability in efficacy still persists suggesting that additional so far disregarded enzymes are required for efficient islet cleavage.
Methods:
Varying activities of a tryptic-like enzyme were identified within collagenase NB1 lots, which were selected according to a matched ratio between tryptic-like and collagenase activity (TLA-ratio). Rat and human pancreata were processed with current standard procedures.
Results:
Increasing the TLA-ratio from 1.3% to 10% reduced pancreas dissociation time in rats by 50% without affecting islet yield, viability, or posttransplant function in diabetic nude mice. Enhancing the TLA-ratio from 1.3% to 12.6% for human pancreas processing resulted in a significant reduction of recirculation time and increased incrementally human islet yield without affecting purity, in vitro function or recovery after culture. Optimized pancreas digestion correlated with a higher percentage of islet preparations fulfilling quality criteria for clinical transplantation.
Conclusions:
We conclude that TLA is an effective component that should be included in moderate amounts in enzyme blends for human islet isolation to optimize the efficiency and minimize the lot-related variability.
