Isokinetic gradient centrifugation prolongs survival of pig islets xenografted into mice

Bioprinted 3D Bionic Scaffolds with Pancreatic Islets as a New Therapy for Type 1 Diabetes-Analysis of the Results of Preclinical Studies on a Mouse Model

Recently, tissue engineering, including 3D bioprinting of the pancreas, has acquired clinical significance and has become an outstanding potential method of customized treatment for type 1 diabetes mellitus. The study aimed to evaluate the function of 3D-bioprinted pancreatic petals with pancreatic islets in the murine model. A total of 60 NOD-SCID (Nonobese diabetic/severe combined immunodeficiency) mice were used in the study and divided into three groups: control group; IsletTx (porcine islets transplanted under the renal capsule); and 3D bioprint (3D-bioprinted pancreatic petals with islets transplanted under the skin, on dorsal muscles). Glucose, C-peptide concentrations, and histological analyses were performed. In the obtained results, significantly lower mean fasting glucose levels (mg/dL) were observed both in a 3D-bioprint group and in a group with islets transplanted under the renal capsule when compared with untreated animals. Differences were observed in all control points: 7th, 14th, and 28th days post-transplantation (129, 119, 118 vs. 140, 139, 140; p < 0.001). Glucose levels were lower on the 14th and 28th days in a group with bioprinted petals compared to the group with islets transplanted under the renal capsule. Immunohistochemical staining indicated the presence of secreted insulin-living pancreatic islets and neovascularization within 3D-bioprinted pancreatic petals after transplantation. In conclusion, bioprinted bionic petals significantly lowered plasma glucose concentration in studied model species.

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.

Isolation, density purification, and in vitro culture maintenance of functional caprine islets of Langerhans as an alternative islet source for diabetes study

BACKGROUND

Insufficient availability of human donors makes the search for alternative source of islet cells mandatory for future developments in pancreatic transplantation. The present study investigates the potential of caprine as an alternative source of pancreatic islets. The objectives of the study were to optimize techniques for caprine islet isolation and purification for culture establishment, and to subsequently assess their viable and functional potential.

METHODS

Caprine pancreatic tissues were collected from a local slaughterhouse and prior transported to the laboratory by maintaining the cold chain. Islets were obtained by a collagenase-based digestion and optimized isolation technique. Islet cell purity and viability were determined by dithizone and trypan blue staining, respectively. Islet clusters of different sizes were positively identified by staining methods and demonstrated 90% viability in the culture system. Following static incubation, an in vitro insulin secretion assay was carried out and analyzed by ELISA.

RESULTS

The islets remained satisfactorily viable for 5 days in the culture system following regular media changes. The current study has successfully optimized the isolation, purification and culture maintenance of caprine islets.

CONCLUSION

The successful yield, viability and functionality of islets isolated from the optimized protocol provide promising potential as an alternative source of islets for diabetes and transplantation researches.

Factors influencing Islet of Langerhans graft function and monitoring

Transplantation of islet of Langerhans represents a viable therapeutic option for insulin-dependent diabetes mellitus. Dramatic progress has been recently reported with the introduction of a glucocorticoid-free immunosuppressive regimen that improved success rate, namely, insulin independence for 1 year or more, from 8% to 100%. The fate of islet grafts is determined by many concurrent phenomena, some of which are common to organ grafts (i.e. rejection), while others are unique to nonvascularized cell transplants, including transplant cell mass and viability, as well as nonspecific inflammation at the site of implant. Moreover, islet grafts lack clinical markers of early rejection, making it difficult to recognize imminent rejection and to implement intervention with graft-saving immunosuppressive regimens. In the present review, we will address the problems influencing islet graft success and the monitoring of islet cell graft function.