Is There an Optimal Enzyme Dose for Human Islet Isolation?

Thursday, June 18, 2026 | 11 AM EST

Presented by
Appakalai N. Balamurugan
Robert McCarthy
Mike Green
Doug O’Gorman

The title of the upcoming webinar came from a question asked by an attendee of VitaCyte’s last webinar, in which Bala reviewed his method to improve islet recovery from young donors: “Is there an optimal enzyme dose for human islet isolation?” I have assembled a panel of experts listed above to discuss the rationale for setting the dose of collagenase-protease enzyme mixtures used for human islet isolation.

It begins with Liberase HI, which uses the enzyme activities found in good lots of Collagenase P to dose per organ, followed by modifications made at the University of Minnesota to change enzyme dosing from per organ to per g of trimmed tissue. The first and only design-of-experiment approach used to prospectively determine the optimal dose of recombinant class I (rC1) and class II (rC2) C.histolyticum collagenase on human islet yields showed that, within the range of rC1 and rC2 doses used, the ratio of rC1 to rC2 did not affect islet yield. Results from further studies at the University of Louisville and the University of Alberta applied the results from the DOE study to provide new insights into the impact of collagenase on human islet yield, function, and recovery after short-term culture. The webinar will conclude with a discussion of the importance of neutral protease in improving islet yield and function.

Appakalai N. Balamurugan, PhD
Professor, Pediatric Endocrinology
Director, Islet Biology & Transplantation
Wendy Novak Diabetes Institute
University of Louisville, Norton Healthcare
Louisville, KY, 40202, USA

Doug O’Gorman
Senior Islet Specialist
Gift of Life Alberta
Clinical Islet Laboratory
Edmonton, Alberta

Doug is the Senior Islet Specialist with the Gift of Life Alberta –  Clinical Islet Laboratory in Edmonton, Alberta. He has 25 years of experience in clinical islet isolation and transplantation. The Edmonton program is one of the most active islet transplant programs in the world, having performed over 2,000 islet isolations and 800 islet transplant procedures to date. He oversees day-to-day laboratory operations, has contributed to peer-reviewed research in the field, and is actively involved in quality improvement and outcomes analysis across the program.

Robert McCarthy
President & Co-Founder
VitaCyte
Indianapolis, Indiana

Bob McCarthy received a Ph.D. in immunology from Indiana University and did post-graduate training at the Mayo Clinic in Rochester, MN, on immunological research and development of clinical immunoassays. He joined Boehringer Mannheim Biochemicals in Indianapolis in 1987 as a Research Investigator and moved to Business Development and later Strategic Planning after the Roche acquisition of Boehringer Mannheim in 1998. In 1992, he led the R&D team that developed the Liberase HI Purified Enzyme Blend product to improve human islet recovery. In 2004, Francis Dwulet and Bob co-founded VitaCyte to improve the manufacture and characterization of collagenase and protease enzymes used for cell isolation and other biomedical applications. VitaCyte’s mission is to develop products that increase research productivity or improve clinical outcomes.

Mike Green
Director of Quality Control
VitaCyte
Indianapolis, Indiana

Mike Green received a Ph.D. in Animal Science (Reproductive Physiology) from Purdue University and did post-doctoral training at the University of Florida on maternal-conceptus interactions during early pregnancy in the pig.  He joined VitaCyte in 2008 where he has performed over 400 islet isolations from various porcine models and numerous human hepatocyte isolations in an effort to better define optimal enzyme formulations for these applications. In 2015, he moved into the role of Quality Control Director where he oversees daily QC activities for product release and is also actively involved in assay development and improvement and technical support.