Immune protection of artificial tissue by means of pancreatic islet microencapsulation is a very ambitious new approach to avoid life-long immune suppression. But the success in the utilization of the alginate-beads with incorporated islets is unfortunately limited. Some of the problems cannot be solved by a two-component system, so polymer encapsulation of the microbeads was tested to improve the properties. In the present paper a pure nanoencapsulation multilayer approach was tested in order to reduce the size of the capsule and possibly apply in the future a multilayer capsule with individual properties in each layer or region of the capsule. Different polycations were attached in a self-assembly process. The advantage in using the surface charge of islets as binding site for the polyions is the guarantee of complete coverage after the second layer. Release of insulin was determined to characterize the function of the islets after encapsulation as well as the permeability of the capsule. Fluorescence microscopy was used to visualize the polyelectrolyte layers. Finally by means of an immune assay, the protection capability of the capsule was proved. In these first measurements the encapsulation with a multilayer nanocapsule was shown to be a possible alternative to the more space-consuming and random islet-trapping microencapsulation.

Insulin expression in the thymus has been implicated in regulating the negative selection of autoreactive T cells and in mediating the central immune tolerance towards pancreatic b-cells. To further explore the function of this ectopic insulin expression, we knocked out the mouse Ins2 gene specifically in the Aire-expressing medullary thymic epithelial cells (mTECs), without affecting its expression in the b-cells. When further crossed to the Ins1 knockout background, both male and female pups (designated as ID-TEC mice for insulin-deleted mTEC) developed diabetes spontaneously around 3 weeks after birth. b-cell-specific autoimmune destruction was observed, as well as isletspecific T cell infiltration. The presence of insulin-specific effector T cells was shown using ELISPOT assays and adoptive T cell transfer experiments. Results from thymus transplantation experiments proved further that depletion of Ins2 expression in mTECs was sufficient to break central tolerance and induce anti-insulin autoimmunity. Our observations may explain the rare cases of type 1 diabetes onset in very young children carrying diabetes-resistant HLA class II alleles. ID-TEC mice could serve as a new model for studying this pathology.

These data suggest that the E23K variant in KCNJ11 may influence the variability in the response of patients to sulfonylureas, thus representing an example of pharmacogenetics in type 2 diabetes.

One of the major obstacles in organ transplantation is to establish immune tolerance of allografts. Although immunosuppressive drugs can prevent graft rejection to a certain degree, their efficacies are limited, transient, and associated with severe side effects. Induction of thymic central tolerance to allografts remains challenging, largely because of the difficulty of maintaining donor thymic epithelial cells in vitro to allow successful bioengineering. Here, the authors show that three-dimensional scaffolds generated from decellularized mouse thymus can support thymic epithelial cell survival in culture and maintain their unique molecular properties. When transplanted into athymic nude mice, the bioengineered thymus organoids effectively promoted homing of lymphocyte progenitors and supported thymopoiesis. Nude mice transplanted with thymus organoids promptly rejected skin allografts and were able to mount antigen-specific humoral responses against ovalbumin on immunization. Notably, tolerance to skin allografts was achieved by transplanting thymus organoids constructed with either thymic epithelial cells coexpressing both syngeneic and allogenic major histocompatibility complexes, or mixtures of donor and recipient thymic epithelial cells. Our results demonstrate the technical feasibility of restoring thymic function with bioengineered thymus organoids and highlight the clinical implications of this thymus reconstruction technique in organ transplantation and regenerative medicine.

Therefore, gliclazide protected human beta-cells from apoptosis induced by intermittent high glucose, and this effect was likely to be due, at least in part, to the anti-oxidant properties of the molecule.

The therapy of type 1 diabetes is an open challenging problem. The restoration of normoglycemia and insulin independence in immunosuppressed type 1 diabetic recipients of islet allotransplantation has shown the potential of a cell-based diabetes therapy. Even if successful, this approach poses a problem of scarce tissue supply. Xenotransplantation can be the answer to this limited donor availability and, among possible candidate tissues for xenotransplantation, porcine islets are the closest to a future clinical application. Xenotransplantation, with pigs as donors, offers the possibility of using healthy, living, and genetically modified islets from pathogen-free animals available in unlimited number of islets. Several studies in the pig-to-nonhuman primate model demonstrated the feasibility of successful preclinical islet xenotransplantation and have provided insights into the critical events and possible mechanisms of immune recognition and rejection of xenogeneic islet grafts. Particularly promising results in the achievement of prolonged insulin independence were obtained with newly developed, genetically modified pigs islets able to produce immunoregulatory products, using different implantation sites, and new immunotherapeutic strategies. Nonetheless, further efforts are needed to generate additional safety and efficacy data in nonhuman primate models to safely translate these findings into the clinic.

Chronic pancreatitis is an inflammatory disease of the pancreas that causes permanent changes in the function and structure of the pancreas. It is most commonly a complication of cystic fibrosis or due to a genetic predisposition. Chronic pancreatitis generally presents symptomatically as recurrent abdominal pain, which becomes persistent over time. The pain eventually becomes disabling. Once specific medical treatments and endoscopic interventions are no longer efficacious, total pancreatectomy is the alternative of choice for helping the patient achieve pain control. While daily administrations of digestive enzymes cannot be avoided, insulin-dependent diabetes can be prevented by transplanting the isolated pancreatic islets back to the patient. The greater the number of islets infused, the greater the chance to prevent or at least control the effects of surgical diabetes. We present here a technical approach for the isolation and preservation of the islets proven to be efficient to obtain high numbers of islets, favoring the successful treatment of young patients.

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