Histological and Immunopathological Analysis of Recovered Encapsulated Allogeneic Islets From Transplanted Diabetic Bb/W Rats

Deletion of the tissue response against alginate-pll capsules by temporary release of co-encapsulated steroids

“…It is unlikely that the shortterm release in the concentrations applied in the present approach will have any effect in the systemic circulation or in the peripheral tissues of the recipients. This is corroborated by the findings of Wijsman who found prolonged survival of allogenic islets in dexamethasone treated BB-rats [31]. The tissue response against capsules in the first week is composed of monocytes/macrophages, granulocytes, fibroblasts, erythrocytes, multinucleated giant cells, and basophiles [15].…”

Biological and Biomaterial Approaches for Improved Islet Transplantation

“…This pericapsular infiltrate, composed predominantly of macrophages and some helper T-cells, results in necrosis of the encapsulated islets. Importantly, immunosuppressive agents, e.g., cyclosporine, inhibit formation of this capsule (Wijsman et al, 1992). The fibrotic capsule consists of multinucleate fibroblasts, which generate a diffusive barrier to the flow of nutrients, oxygen, and metabolites.…”

Alginate encapsulation technology supports embryonic stem cells differentiation into insulin-producing cells

“…alginate concentration, alginate composition, bead size and cell seeding density) to meet various cell culture parameters. Alginate-based systems have been widely tested for islet encapsulation (Cui et al, 2004;Figliuzzi et al, 2006) and been shown to provide immuno-isolation after the system transplantation, thus prolonging the survival of encapsulated islets, and to restore glucose homeostasis over the prolonged time period (Cui et al, 2004;Omer et al, 2005;Wijsman et al, 1992). The alginate technology has also been applied to encapsulation and differentiation of embryonic bodies (Magyar et al, 2001;Gerecht-Nir et al, 2004), while encapsulation of individual stem cells for the purpose of their differentiation into hepatocytes, omitting the EB stage, was recently reported in two publications from Yarmush's laboratory (Maguire et al, 2006(Maguire et al, , 2007.…”