The Study of the Effectiveness of Extracellular Matrix On Islet Transplantation.

Abstract

Background and Aim. Islet transplantation has been performed via portal vein in clinical, but intraportal transplantation has some demerits in transplant efficacy and safety. Muscle is one of the candidates of transplant site for islet instead of liver, but the transplant efficacy is inferior to that of liver. Extracellular matrix, an extracellular part of multicellular structure, provides some growth factors which act on cellular progression and differentiation. It is considered that extracellular matrix may support the engraftment of intramuscular transplanted islets and improve the transplant efficacy. In this study, we attempted to clarify the effectiveness of extracellular matrix in culturing islets in in vitro assay. Materials and Methods. Male BALB / c mice were used for islet donors. The isolated islets were cultured for 96 hours with or without Matrigel (BD Matrigel basement membrane matrix). Matrigel contains rich extracellular matrixes including laminin, collagen IV, entactin, and heparan sulfate proteoglycan. The effectiveness of Matrigel was evaluated by residual rate of cultured islets (the percentage of the residual islet numbers in comparison with the numbers at the time of starting culture), viable rate of cultured islets (percentage of viable cells in islet), and stimulation index (SI). The groups were classified as Matrigel group (islets were cultured in Matrigel) and non Matrigel group. Results. The residual rate at 96 hours after starting culture was significantly higher in Matrigel group (90.8 ± 1.4% vs 75.6 ± 3.9%, p = 0.002). The viable rate at the same time was also significantly higher in Matrigel group (95.6 ± 0.9% vs 91.1 ± 1.4%, p = 0.016). Furthermore, SI of Matrigel group was also significantly higher at both 24 hours and 96 hours after staring culture (5.3 ± 1.2 vs 2.2 ± 0.4, p = 0.047,and 3.7 ± 0.6 vs 1.9 ± 0.3, p = 0.022). Conclusion. Matrigel could prevent cultured islets from death and dysfunction. It could also improve insulin-releasing function of islets. The effectiveness will be also certified using in vivo intramuscular transplant animal model.