Rapid quantitative assessment of the pig pancreas biopsy predicts islet yield

Heterogenous expression of endocrine and progenitor cells within the neonatal porcine pancreatic lobes-Implications for neonatal porcine islet xenotransplantation

Neonatal porcine islets (NPIs) are a source of islets for xenotransplantation. In the pig, the pancreatic lobes remain separate, thus, when optimizing NPI isolation, the pancreatic lobes included in the pancreatic digest should be specified. These lobes are the duodenal (DL), splenic (SL) and connecting (CL) lobe that correspond to the head, body-tail, and uncinate process of the human pancreas. In this study we are the first to evaluate all three neonatal porcine pancreatic lobes and NPIs isolated from these lobes. We report, a significant difference in endocrine and progenitor cell composition between lobes, and observed pancreatic duct glands (PDG) within the mesenchyme surrounding exocrine ducts in the DL and CL. Following in vitro differentiation, NPIs isolated from each lobe differed significantly in the percent increase of endocrine cells and final cell composition. Compared to other recipients, diabetic immunodeficient mice transplanted with NPIs isolated from the SL demonstrated euglycemic control as early as 4 weeks (p < 0.05) and achieved normoglycemia by 6 weeks post-transplant (p < 0.01). For the first time we report significant differences between the neonatal porcine pancreatic lobes and demonstrate that NPIs from these lobes differ in xenograft function.

Pancreatic Islets: Methods for Isolation and Purification of Juvenile and Adult Pig Islets

The current situation of organ transplantation is mainly determined by the disbalance between the number of available organs and the number of patients on the waiting list. This obvious dilemma might be solved by the transplantation of porcine organs into human patients. The metabolic similarities which exist between both species made pancreatic islets of Langerhans to that donor tissue which will be most likely transplanted in human recipients. Nevertheless, the successful isolation of significant yields of viable porcine islets is extremely difficult and requires extensive experiences in the field. This review is focussing on the technical challenges, pitfalls and particularities that are associated with the isolation of islets from juvenile and adult pigs considering donor variables that can affect porcine islet isolation outcome.

Pig-islet xenotransplantation: recent progress and current perspectives

Islet xenotransplantation is one prospective treatment to bridge the gap between available human cells and needs of patients with diabetes. Pig represents an ideal candidate for obtaining such available cells. However, potential clinical application of pig islet still faces obstacles including inadequate yield of high-quality functional islets and xenorejection of the transplants. Adequate amounts of available islets can be obtained by selection of a suitable pathogen-free source herd and the development of isolation and purification method. Several studies demonstrated the feasibility of successful preclinical pig-islet xenotransplantation and provided insights and possible mechanisms of xenogeneic immune recognition and rejection. Particularly promising is the achievement of long-term insulin independence in diabetic models by means of distinct islet products and novel immunotherapeutic strategies. Nonetheless, further efforts are needed to obtain much more safety and efficacy data to translate these findings into clinic.

Concentration and chain length of polyethylene glycol in islet isolation solution: evaluation in a pancreatic islet transplantation model

To improve graft preservation and consequently reduce conservation injuries, the composition of preservation solution is of outmost importance. It was demonstrated that the colloid polyethylene glycol (PEG), used in SCOT solution, has protective effects on cell membranes and immunocamouflage properties. The aim of this study was to optimize the concentration and chain length of PEG to improve pancreatic islet preservation and outcome. In a model of murine islet allotransplantation, islets were isolated with SCOT containing various concentrations of PEG 20 kDa or 35 kDa. Better islet yield (IEQ) was obtained with SCO +PEG at 15-30 g/L versus other PEG concentrations and control CMRL-1066 + 1% BSA solution (p < 0.05). Allograft survival was better prolonged (up to 20 days) in the groups SCOT + PEG 20 kDa 10-30 g/L compared to PEG 35 kDa (less than 17.8 days) and to control solutions (less than 17.5 days). In terms of graft function recovery, the use of PEG 20 kDa 15-30 g/L induced no primary nonfunction and delayed graft function contrary to CMRL-1066 and other PEG solutions. The use of the extracellular-type solution SCOT containing PEG 20 kDa 15 g/L as colloid could be a new way to optimize graft integrity preservation and allograft outcome.