Two-layer cold storage method for pancreas and islet cell transplantation

Necessities for a Clinical Islet Program

For more than two decades we have been refining advances in islet cell transplantation as a clinical therapy for patients suffering from type 1 diabetes. A great deal of effort has gone to making this a viable therapy for a broader range of patients with type 1 diabetes. Clinical results have progressively improved, demonstrating clinical outcomes on par with other organ transplants, specifically in terms of insulin independence, graft and patient survival. We are now at the point where islet cell transplantation, in the form of allotransplantation, has become accepted as a clinical therapy in adult patients affected by type 1 diabetes, in particular those suffering from severe hypoglycaemic unawareness. This chapter provides an overview on how this has been undertaken over the years to provide outcomes on par with other organ transplantation results. In particular this chapter focuses on the processes and facilities that are required to establish a clinical islet isolation and transplantation program. It also outlines the very important underpinning processes of selection of the organ donor for islet isolation, the processes of organ donor operation and preservation of the pancreas by various means and the ideal ways to best improve outcomes for human islet cell isolation. Providing these more optimal conditions we can underpin the isolation processes to provide islets for transplantation and as such a safe, effective and feasible therapeutic option for an increasing number of patients suffering from type 1 diabetes with severe hypoglycaemic unawareness.

Pancreatic islet transplantation: from dogs to humans and back again

Pancreatic islet transplantation is a cell-based therapy that provides a potential cure for type 1 diabetes mellitus. After the introduction of an automated method for islet isolation and steroid-free immunosuppressive protocols, reversal of diabetes by islet transplantation is now performed at major human medical centers around the world. Despite extensive use of animal models in islet transplantation research, practical concerns have slowed the introduction of the technique into clinical veterinary practice and only a small number of studies have reported results of transplantation in dogs with spontaneously occurring diabetes mellitus; however, recent advances in islet isolation and encapsulation may make it possible to perform islet transplantation without immunosuppression in companion animals. This review summarizes experimental and clinical studies of pancreatic islet transplantation in dogs, including future directions for cell therapy in animals with naturally occurring disease.

Pancreatic islet allograft in spleen with immunosuppression with cyclosporine. Experimental model in dogs

PURPOSE

To study the functional behavior of the allograft with immunosuppression of pancreatic islets in the spleen.

METHODS

Five groups of 10 Mongrel dogs were used: Group A (control) underwent biochemical tests; Group B underwent total pancreatectomy; Group C underwent total pancreatectomy and pancreatic islet autotransplant in the spleen; Group D underwent pancreatic islet allograft in the spleen without immunosuppressive therapy; Group E underwent pancreatic islet allograft in the spleen and immunosuppression with cyclosporine. All of the animals with grafts received pancreatic islets prepared by the mechanical-enzymatic method - stationary collagenase digestion and purification with dextran discontinuous density gradient, implanted in the spleen.

RESULTS

The animals with autotransplant and those with allografts with immunosuppression that became normoglycemic showed altered results of intravenous tolerance glucose (p < 0.001) and peripheral and splenic vein plasmatic insulin levels were significantly lower (p < 0.001) in animals that had allografts with immunosuppression than in those with just autotransplants.

CONCLUSIONS

In the animals with immunosuppression with cyclosporine subjected to allograft of pancreatic islets prepared with the mechanical-enzymatic preparation method (stationary collagenase digestion and purification with dextran discontinuous density gradient), the production of insulin is decreased and the response to intravenous glucose is altered.

The current state of knowledge of hepatic ischemia-reperfusion injury based on its study in experimental models

The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R) injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

Pancreas anatomy and surgical procedure for pancreatectomy in rhesus monkeys

BACKGROUND

The aim of this study was to investigate the pancreas anatomy and surgical procedure for harvesting pancreas for islet isolation while performing pancreatectomy to induce diabetes in rhesus monkeys.

METHODS

The necropsy was performed in three cadaveric monkeys. Two monkeys underwent the total pancreatectomy and four underwent partial pancreatectomy (70-75%).

RESULTS

The greater omentum without ligament to transverse colon, the cystic artery arising from the proper hepatic artery and the branches supplying the paries posterior gastricus from the splenic artery were observed. For pancreatectomy, resected pancreas can be used for islet isolation. Diabetes was not induced in the monkeys undergoing partial pancreatectomy (70-75%).

CONCLUSIONS

Pancreas anatomy in rhesus monkeys is not the same as in human. Diabetes can be induced in rhesus monkeys by total but not partial pancreatectomy (70-75%). Resected pancreas can be used for islet isolation while performing pancreatectomy to induce diabetes.

Prevention of intimal hyperplasia employing the cavitary two-layer method in allogeneic rat heart transplantation

BACKGROUND

The development of graft arteriosclerosis is a significant contributor to chronic rejection in organ transplant recipients. The purpose of the present study was to establish whether or not the cavitary two-layer method can prevent graft arteriosclerosis after rat heart transplantation.

METHODS

F-344 rats served as donors to Lewis recipients. Grafts in the control group (group C) were immediately allotransplanted without preservation. Grafts were also transplanted after cold preservation for 3 h in University of Wisconsin solution (group UW), or employing the cavitary two-layer (CTL) method (group TL). In another group (group W), grafts were subjected to 15-min warm ischemia and then transplanted. Grafts damaged by ischemia were also transplanted after preservation for 3 h using CTL (group WTL). We measured intimal thickening (IT) before transplantation and at 30 and 60 d post-transplant and also assessed the expression of heat shock proteins (HSPs).

RESULTS

At 60 d post-transplant, IT in group WTL was significantly lower than in group W (0.30 ± 0.03 versus 0.45 ± 0.04, respectively). In contrast, no significant changes were observed in the cold storage groups. Expression of HSPs 60 and 70 at 60 d in group WTL (25.40% ± 1.64% and 35.96% ± 2.65%, respectively) was reduced compared with group W (46.07% ± 5.84% and 55.11% ± 1.54%, respectively).

CONCLUSIONS

CTL reduces IT induced by warm ischemia in rat heart transplantation, and allows the maintenance of low HSP 60 and 70 expression.