ABSTRACT
Islet transplantation is one of the effective therapies for diabetes mellitus. Nevertheless, multiple issues still exist, such as shortage of donors and adverse reactions caused by long-term use of immunosuppressants, which limit the islet survival post-transplantation. Microencapsulated islet transplantation may overcome these difficulties to certain extent, whereas many factors, such as the destruction of immune isolation microenvironment within the microcapsules and insufficient supply of oxygen and nutrients, constrain the application of microencapsulated islet transplantation in clinical practice. In recent years, how to enhance the effect of microencapsulated islet transplantation has been gradually studied. The application of stem cells in microencapsulated islet transplantation has steadily become a research hot spot. Therefore, the optimizing strategies for microencapsulated islet transplantation and the application of stem cells in microencapsulated islet transplantation were reviewed, and the potential improvement techniques of microencapsulated islet transplantation were investigated in this article, aiming to provide reference for further clinical application of microencapsulated islet transplantation.
ABSTRACT
Diabetes mellitus is one of the leading metabolic diseases that cause an increasing rate of mortality and morbidity. Recently, rather than the current drug treatment, pancreatic islet transplantation has been regarded as a potentially promising strategy for insulin- dependent diabetes mellitus while preventing complications such as kidney damage, vascular damage, nerve damage, and blindness. Recently, a number of advanced islet encapsulation techniques have been designed to enhance the efficiency of islet transplantation, including cell sheet engineering and generation of 3D islet spheroids by high density suspension system (HDSS). Chondrocytes derived from cartilage sources have been used as an encapsulation biomaterial for islets not only for autograft but also for allograft and xenograft transplantation. Cartilage is an avascular, white connective tissue that is rich in extracellular matrix, and expandable in vitro. Hence, this tissue might have immunologically privileged properties that make it an intelligent cell source for manufacture of encapsulation biomaterials. However, cell sheet engineering and HDSS still have their respective limitations, which need to be elucidated. This review will describe the advantages and disadvantages of the current encapsulation techniques in order to provide a comprehensive foundation for further modifications and improvements of tissue engineering for islet transplantation.
Subject(s)
Allografts , Autografts , Biocompatible Materials , Blindness , Cartilage , Chondrocytes , Connective Tissue , Diabetes Mellitus , Extracellular Matrix , Islets of Langerhans , Islets of Langerhans Transplantation , Kidney , Metabolic Diseases , Mortality , Tissue Engineering , Transplantation, HeterologousABSTRACT
Objective:To study the immunoisolation effects of alginate-polylysine-alginate(APA)-microcapsules in vito.Methods:To observe changes of cellular immune and tectology of sheeps after hollow microcapsules, Bovine Chromaffin Cells(BCCs) and APA Microencapsulated BCCs(APA-BCCs) transplanted to the spinal subarachnoid space.Results:The blood lymphocyte numbers of each group didn't change; APA-microcapsule could prevent blood CD4 +T lymphocyte , CD4 +/CD8 + and CSF lymphocyte from increasing caused by BCCs transplantation; APA microencapsulation could reduce histological reactions in transplantation area and prolong the survival of the transplant.Conclusion:APA microcapsules possess the immunoisolation effects and can efficiently prevent immunoreactions.
ABSTRACT
There have been great developments in pancreas and pancreatic islet cell transplantion in the last few years. The isolation of the islet cells in capsules with semi-permeable membranes may become ideal means of treating diabetes, and the use of immunossuppression could be avoided. The ideal material for the confection of the capsules has remained a dream. A new material derived from natural latex was implanted in the subcutaneous tissue of normal and diabetic rats to study the biocompatibility and the vascular neoformation. After 21 days, an analysis of the implant showed intense vascular neoformation on the membrane-tissue interface and little fibrotic tissue. The inicial results show great promise for utilization of this material in capsules for the isolation of cells.
O transplante de pâncreas e de ilhotas pancreáticas vem apresentando grande desenvolvimento nos últimos anos. O isolamento das ilhotas em cápsulas com membrana semi-permeáveis pode ser tratamento de escolha para o diabetes, pois dispensa o uso de imunossupressores. O material ideal para a confecção de uma cápsula para o isolamento celular ainda permanece um sonho. Um novo material a base de látex natural foi implantado no subcutâneo de ratos normais e diabéticos para estudar a biocompatibilidade e a neoformação vascular. A análise após 21 dias de implante mostrou intensa formação capilar na interface membrana-tecido e pouco tecido fibrótico. Estes achados iniciais mostram que o material pode ter algum potencial para a confecção de dispositivos de isolamento celular.