title: Harmful delayed effects of exogenous isolation enzymes on isolated human islets: relevance to clinical transplantation.
abstract: The isolation process exposes human pancreatic islets to exogenous isolation enzymes. Exposure to these enzymes, as a result of intraductal injection in the pancreas or simple contact of islets with enzyme components, causes internalization into the islet cells of enzymes and their by-products. Human islets exposed to Liberase-HI exhibit a decreased insulin secretory ability that correlates with the time of exposure. This phenomenon is paralleled by increased expression of adhesion molecules (CD106 and CD62p) and activation of apoptotic pathways (Bax and Bcl-2) in islet cells. Increased functional impairment is also observed after islet transplantation in diabetic immunodeficient mice. Experimental exposure of islet grafts to exogenous isolation enzymes causes intense inflammation (CD11b positive cells) at the transplant site and it was associated with sickness behavior and eventually death of mouse recipients. The extent of these adverse effects likely deceives the standard qualitative protocols currently in use to assess islet quality in vitro. Reducing the secondary effects of exogenous isolation enzymes on isolated human islets may be crucial to enhance the quality of islets as tissue grafts.
authors.affiliation: Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Balamurugan
authors.forename: Jing
authors.initials: J
authors.lastname: He
authors.forename: Fengli
authors.initials: F
authors.lastname: Guo
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
authors.forename: Suzanne
authors.initials: S
authors.lastname: Bertera
authors.forename: Xuehui
authors.initials: X
authors.lastname: Geng
authors.forename: Xinhui
authors.initials: X
authors.lastname: Ge
authors.forename: Massimo
authors.initials: M
authors.lastname: Trucco
authors.forename: Rita
authors.initials: R
authors.lastname: Bottino
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D017364:Collagenases / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D016381:Islets of Langerhans Transplantation / Q000473:pathology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013820:Thermolysin / Q000493:pharmacokinetics / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D007328:Insulin; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D017364:Collagenases; C106635:Liberase; D013820:Thermolysin