A Method for Performing Islet Transplantation Using Tissue-Engineered Sheets of Islets and Mesenchymal Stem Cells

Abstract

Mesenchymal stem cells (MSCs) are known to have a protective effect on islet cells. Cell sheets developed using tissue engineering help maintain the function of the cells themselves. This study describes a tissue engineering approach using islets with MSC sheets to improve the therapeutic effect of islet transplantation. MSCs were obtained from Fischer 344 rats and engineered into cell sheets using temperature-responsive culture dishes. The islets obtained from Fischer 344 rats were seeded onto MSC sheets, and the islets with MSC sheets were harvested by low-temperature treatment after coculture. The functional activity of the islets with MSC sheets was confirmed by a histological examination, insulin secretion assay, and quantification of the levels of cytokines. The therapeutic effects of the islets with MSC sheets were investigated by transplanting the sheets at subcutaneous sites in severe combined immunodeficiency (SCID) mice with streptozotocin-induced diabetes. Improvement of islet function and viability was shown in situ on the MSC sheet, and the histological examination showed that the MSC sheet maintained adhesion factor on the surface. In the recipient mice, normoglycemia was maintained for at least 84 days after transplantation, and neovascularization was observed. These results demonstrated that islet transplantation in a subcutaneous site would be possible by using the MSC sheet as a scaffold for islets.

Modular tissue engineering for the vascularization of subcutaneously transplanted pancreatic islets

“…The primary challenge of the s.c. site for the transplantation of pancreatic islets is ensuring proper vascularization. Other groups have attempted to use the s.c. site with different systems, but these typically need excess islets to achieve glycemic control due to poor vascularization and a corresponding lack of direct integration with the host (28,30,31). For example, Hirabaru et al (30) used an MSC sheet to s.c. transplant 2,000 rat islets to rectify diabetes in SCID/bg mice for 28 d, but they were unable to achieve a therapeutic effect with a lower dosage of islets.…”

“…Other groups have attempted to use the s.c. site with different systems, but these typically need excess islets to achieve glycemic control due to poor vascularization and a corresponding lack of direct integration with the host (28,30,31). For example, Hirabaru et al (30) used an MSC sheet to s.c. transplant 2,000 rat islets to rectify diabetes in SCID/bg mice for 28 d, but they were unable to achieve a therapeutic effect with a lower dosage of islets. Similar islet numbers (2,000-3,000) are reported by others for s.c. normoglycemia in xenograft models in immune-compromised mice (13,30,32).…”

“…For example, Hirabaru et al (30) used an MSC sheet to s.c. transplant 2,000 rat islets to rectify diabetes in SCID/bg mice for 28 d, but they were unable to achieve a therapeutic effect with a lower dosage of islets. Similar islet numbers (2,000-3,000) are reported by others for s.c. normoglycemia in xenograft models in immune-compromised mice (13,30,32). The success (or lack of success) of xenogeneic islet transplantation, largely in the kidney capsule, has been reviewed elsewhere (33).…”

“…3 D and E). Such an integrated and perfusable vasculature was a highlight here but was not hitherto a feature of previous s.c. implant studies (13,30).…”

Tissue‐engineering approaches in pancreatic islet transplantation

“…During the last few years, MSCs have been the cell type most frequently used in islet transplantation approaches, due to their proangiogenic and immunomodulatory paracrine effects (Hematti, Kim, Stein, & Kaufman, ; Sakata, Goto, Yoshimatsu, Egawa, & Unno, ; T. Wu, Liu, Wang, & Li, ). MSCs, which are obtained from different tissues, such as bone marrow, adipose tissue, or Wharton’s Jelly, have been shown to enhance graft immune tolerance (reducing or even avoiding the use of immunosuppressive drugs), while increasing the vascular density and reducing islet cell apoptosis when simply cotransplanted with islets (Ben Nasr et al, ; Berman et al, ; Borg et al, ; Cao, Li, Sun, Ge, & Liu, ; Cavallari et al, ; Ding et al, ; Figliuzzi et al, ; Ito et al, ; Jacobson, Kumagai‐Braesch, Tibell, Svensson, & Flodström‐Tullberg, ; Ohmura et al, ; Unsal et al, ; H. Wu, Wen, & Mahato, ; Xu et al, ; Yoshimatsu et al, ) in several tissue‐engineering approaches using micro‐ (Buitinga et al, ; Kerby, Jones, Jones, & King, ; Vériter et al, ) and macro‐encapsulation (Borg et al, ; Davis et al, ; Hamilton et al, ; Pérez‐Basterrechea et al, ; Vériter et al, ) or even when using MSCs as a cell sheet (Hirabaru et al, ), mainly at extrahepatic sites.…”