Advances in Encapsulation and Delivery Strategies for Islet Transplantation

Abstract

Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease caused by the destruction of pancreatic 𝜷-cells in response to autoimmune reactions. Shapiro et al. conducted novel islet transplantation with a glucocorticoid-free immunosuppressive agent in 2000 and achieved great success; since then, islet transplantation has been increasingly regarded as a promising strategy for the curative treatment of T1DM. However, many unavoidable challenges, such as a lack of donors, poor revascularization, blood-mediated inflammatory reactions, hypoxia, and side effects caused by immunosuppression have severely hindered the widespread application of islet transplantation in clinics. Biomaterial-based encapsulation and delivery strategies are proposed for overcoming these obstacles, and have demonstrated remarkable improvements in islet transplantation outcomes. Herein, the major problems faced by islet transplantation are summarized and updated biomaterial-based strategies for islet transplantation, including islet encapsulation across different scales, delivery of stem cell-derived beta cells, co-delivery of islets with accessory cells and immunomodulatory molecules are highlighted.

3D Printing Mini-Capsule Device for Islet Delivery to Treat Type 1 Diabetes

“…Islets are often subjected to immune damage after transplantation; therefore, encapsulating islets in biomaterials has been extensively applied to shield them from immunological damage after transplantation . Based on the biocompatibility of the hydrogels depicted in Figure and Figure under different exposure times, we first mixed 100 islets (≈60 IEQ) with the GelMA solution for direct printing.…”

Type 1 diabetes and engineering enhanced islet transplantation

“…Microencapsulation devices are often composed of hydrogels such as alginate, agarose, or collagen. We discuss the use of different scaffolds later in this review, which is also detailed by Wu et al [250] . A thorough review of microencapsulation from the viewpoint of vascularization and the immune response can be found at Barkai et al [251] .…”

Natural Biopolymers as Additional Tools for Cell Microencapsulation Applied to Cellular Therapy

“…The advantage of using alginate, especially alginate commercially sold as ultrapure and with a high guluronic acid ratio, is a lower probability of immunogenic reactions and higher tissue recovery chances [133]. However, an inherent limitation of in vivo alginate procedures, depending on the time for which the biomaterial will remain inside the living organism, is a high degradation rate over time, although this possibility of degradation in vivo is great but can be solved by associating other polymers with the alginate matrix [134]. Therefore, complementary studies are required to clarify these questions and improve the use of this biopolymer in cell bioengineering, as well as to enable the use of alginate as a bioink in 3D printers aimed at the production of three-dimensional organotypical structures in order to, in the future, be able to replace injured tissues.…”