Modified surface alginate microsphere releasing insulin for modulation of foreign body response in islet transplantation

Biocompatible hydrogels have great potential for applications in various field of regenerative medicine such as drug delivery, 3D culture scaffolds and cell encapsulation due to biocompatibility and biodegradability.Isolation of therapeutic donor cells using biopolymers from host tissue can eliminate the foreign body responses induced by recipient immune cells including macrophages. Pancreatic islet encapsulation in hydrogel has wide utilizations in treating patients suffering from diabetes I owing to cell immunoisolation properties. Conventional biopolymer that used for cell encapsulation act as foreign body and cannot overcome graft rejection by host immune cells. Therefore, considerable fibrotic tissue formation results in that can limit nutrient, oxygen and by-product exchange between encapsulated cells and surrounding milieu. Thus, viability of transplanted cells decreased and no significant reduction in blood glucose was seen.Therefore, various methods for cell encapsulation and reducing of host immune response used in tissue engineering including , cell entrapment in different kinds of hydrogel by microfluidic systems so called microencapsulation. But unfortunately, results of these investigations are unpromising due to the foreign body responses that can reduce viability of the cells within the hydrogels. Recent progress in the field of cell encapsulation using surface modified alginate results in elimination of the foreign body response and increasing of cell viability within the hydrogel. Using these technology, pancreatic B cells derived from embryonic stem cells could decrease hyper glyceumia for long term in the diabetic mice without need to immunosuppressive drugs.

Keywords:

Alginate microsphere , Insulin , Release , Transplantation