The Isolation and Function of Porcine Islets from Market Weight Pigs

Abstract

The efficacy of clinical islet transplantation has been demonstrated with autografts, and although islet allografts have established insulin independence in a small number of IDDM patients, the treatment is confounded by the necessity of immunosuppression. the lack of donor tissue, and recurring islet immunogenicity. These limitations underscore a need to develop therapies to serve the large population of diabetic patients. Porcine islet xenotransplantation, together with a successful immune intervention strategy, may provide the necessary clinical alternative. However, a major obstacle in evaluating this approach has been the difficulty of obtaining adequate volumes of functional islet tissue from pigs. Donors of market weight are preferable to retired breeders due to their abundance, lower animal and husbandry costs. and are more suitable to meet regulatory guidelines for donor tissue for xenotransplantation. We describe a simple isolation procedure that following purification yields a mean of 350,000 IE, corresponding to 179 units of insulin and 1.8 mg of DNA with an islet purity and viability in excess of 85% (n = 317 isolations). In both short- and long-term cell cultures, porcine islets demonstrated glucose-responsive insulin secretion. However, this secretion is density dependent, which may have significant consequences in the development of immunoisolation technologies to support porcine islet xenotransplantation. Following implantation into diabetic nude mice, porcine islets remained functional in excess of 1 year. Implantation of a bioartificial pancreas containing porcine islets into pancreatectomized dogs provided significant clinical benefit with an improved diabetic condition. Finally, secretagogue-induced insulin release was demonstrated in vitro from these devices after removal from immunocompetent recipients. Immunohistochemical staining identified well-granulated islets following long-term implantation in both the rodent and canine models. This study demonstrates the ability to isolate porcine islets in clinically relevant numbers from market animals, which survive and remain functional for prolonged periods of time in an immune-deficient or immunoprotected environment.

Vascularized islet-cell transplantation in miniature swine. I. Preparation of vascularized islet kidneys

“…The excised pancreas was placed in crushed ice immediately, and modified University of Wisconsin (UW) solution was infused through the pancreatic duct (16). Pancreatic tissue was processed at the Joslin Diabetes Center (Boston, MA) (25). After islet isolation, the purity of the preparation was evaluated with dithizone (DTZ) staining.…”

异种胰岛移植中供体猪的筛选: 现状与进展

“…Adult pig is regarded as the primary donor source of islet xenografts, which can supply an adequate amount of viable islet cells and start functioning immediately after implantation (O'Neil et al, 2001;Dufrane et al, 2006). More than 200 000 islet cells with high purity (80%-95%) can be isolated from an adult pig donor (Ricordi et al, 1990;Inoue et al, 1992).…”

Pig islets for clinical islet xenotransplantation

“…Young (12-15 weeks) and adult (>2 years) pig pancreases provide a sufficient quantity of functional islets to perform xenotransplantation into primates [29,30]. Pancreases from young pigs (<12 weeks old) may be procured in a sterile surgical environment and without warm ischaemia time by in-situ cold perfusion, but the endocrine pancreas is still maturing between weeks 5 and 24 and, thus, is inappropriate for transplantation because of isolation difficulties or insufficient function [31,32].…”