Is There an Optimal Enzyme Dose for Human Islet Isolation?

Thursday, June 18, 2026 | 11 AM EST

Presented by
Robert McCarthy
Mike Green
Doug O’Gorman

The title of the upcoming webinar came from a question asked by an attendee at the last webinar, in which Appakalia Balamurugan reviewed his method to improve islet recovery from young donors: “Is there an optimal enzyme dose for human islet isolation?” To broaden this discussion, Bob recruited Mike Green (VitaCyte) and Doug O’Gorman (University of Alberta, Edmonton), who were responsible for setting the dose of VitaCyte recombinant rCollagenase HI product and for performing numerous isolations to validate its performance, respectively.

Bob will begin the story with development of the Liberase™ HI Purified Enzyme Blend, which used the enzyme activities found in good lots of Collagenase P to determine the dose of purified Clostridium histolyticum collagenases and thermolysin used per organ, Mike will review 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. These results showed that, within the range of rC1 and rC2 doses used, the ratio of rC1 to rC2 did not affect islet yield. Doug will review insights from 1094 human islet isolations performed at the University of Alberta. These results indicate that using lower doses of collagenase, combined with an optimal dose of neutral protease, improves in vitro islet function.

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.