PeloNews with Focus on Liver/Islets

Revolution of Enzyme Requirements for
Human Islet Isolation by Bob McCarthy
The quality of collagenase used for mammalian islet isolation has been a focus of clinical
research scientists soon after Ballinger and Lacy demonstrated that islet transplantation
could correct chemically induced diabetes in inbred strains of rats
(1). Clostridium histolyticum collagenase became a critical reagent because of the need
to isolate sufficient numbers of functional islets for islet transplantation in higher
mammals (e.g., dogs, pigs, humans). Typically, researchers evaluated several “lots” of
crude or enriched commercial collagenase products (i.e., traditional collagenase) for
their ability to recover pancreatic islets. The goal of lot qualification was to identify a
“good” lot of traditional collagenase that worked successfully in the islet isolation procedure
before purchasing larger amounts of a specific lot of product for routine use.
Good lots for human islet isolation were hard to find.
Camillo Ricordi’s development of a semi-automated method for human islet isolation
led him to focus on screening new collagenase lots once these lots were released for
sale by a supplier. During this process, Ricordi screened lots of Collagenase P, a crude
collagenase product first sold by Boehringer Mannheim Biochemicals in 1990. He
found that this material worked better for this application than competitive collagenase
products. One lot, lot 9, was used to isolate islets for many allo-islet transplantation
procedures (2). Collagenase P had higher collagenase and lower protease activity than
found in Sigma collagenase products used by many research scientists at that time.
Ricordi’s use of the Collagenase P product in clinical trials led to a meeting <strong>with</strong> R&D
management at Boehringer Mannheim Diagnostics in Indianapolis, Indiana about Boehringer
solving the “collagenase problem.” This discussion led to funding of a research
project at Boehringer Mannheim Biochemicals to identify and purify the key enzymes in
crude collagenase responsible for releasing islets from porcine or human pancreatic
tissue. The assumption was that the identification, purification, and formulation of purified
enzymes used at an appropriate dose would resolve the collagenase problem.
To read full paper, please visit: https://www.vitacyte.com/news/evolution-enzymerequirements-human-islet-isolation-link-recent-review/
Reference:
1 Ballinger WF, Lacy PE. Transplantation of intact pancreatic islets in rats. Surgery. 1972;72(2):175-86.
2 Ricordi C, Tzakis AG, Carroll PB, Zeng YJ, Rilo HL, Alejandro R, et al. Human islet isolation and allotransplantation
in 22 consecutive cases. Transplantation. 1992;53(2):407-14.
Enzymes
VitaCyte’s defined enriched
(DE) collagenase
products set a new
standard of consistency
and enables assessment
of a broader range of
collagenase: protease
ratios for cell isolation
than found <strong>with</strong> current
collagenase products.
DE Collagenase is
designed <strong>with</strong> increasing
amounts of enriched
collagenase added
to a fix amount of purified
BP protease.
Overview Rodent
Islet Overview discussion
of common
protocols used in rodent
islet isolations.
Includes a link to
a white paper that
summarizes a survey
of the affect of rodent
strain, age, sex, or
nutritional state on
expected islet yields
when purified enzymes
were used to isolate
islets. https://
www.vitacyte.com/
product-applications/
rodent-islet-applications