• Journal of Embryo Transfer
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• v.30 no.4
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• pp.305-313
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• 2015

Xenotransplantation of pig islet regarded as a good alternative to allotransplantation. However, cellular death mediated by hypoxia-reoxygenation injury after transplantation disturb success of this technique. In the present study, we produce transgenic pig expressing human heme oxygenase 1 (HO1) genes to overcome cellular death for improving efficiency of islet xenotransplantation. Particularly, Korean miniature pig breed, Micro-Pig, was used in the present study. Somatic cell nuclear transfer (SCNT) technique was used to produce the HO1 transgenic pig. Six alive transgenic piglets were produced and all the transgenic pigs were founded to have transgene in their genomic DNA and the gene was expressed in all tested organs. Also, in vitro cultured fibroblasts derived from the HO1 transgenic pig showed low reactive oxygen species level, improved cell viability and reduced apoptosis level.

• IMMUNE NETWORK
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• v.4 no.1
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• pp.53-59
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• 2004

Background: Minor histocompatibility HY antigen, as a transplantation antigen, has been known to cause graft rejection in MHC (major histocompatibility complex) matched donor-recipient. The aim of our study is to investigate the role of male antigen (HY) disparity on MHC matched pancreatic islet transplantation and to examine the mechanism of the immune reaction. Methods: Pancreatic islets were isolated and purified by collagen digestion followed by Ficoll gradient. The isolated islets of male C57BL6/J were transplanted underneath the kidney capsule of syngeneic female mice rendered diabetic with streptozotocine. Blood glucose was monitored for the rejection of engrafted islets. After certain period of time, tail to flank skin transplantation was performed either on mouse transplanted with HY mismatched islets or on sham treated mouse. The rejection was monitored by scoring gross pathology of the engrafted skin. Results: HY mismatched islets survived more than 300 days in 14 out of 15 mice. The acceptance of second party graft (male B6 islets) and the rejection of third party graft (male BALB/c islets) in these mice suggested the tolerance to islets with HY disparity. B6 Skin with HY disparity was rejected on day $25{\pm}7$. However, HY mismatched skin transplanted on the mice tolerated to HY mismatched islets survived more than 240 days. Tetramer staining in these mice indicated the CTL recognizing MHC Db/Uty was not deleted or anergized. Conclusion: The islet transplantation across HY disparity induced tolerance to HY antigen in C57BL6 mouse, which in turn induced tolerance to HY mismatched skin, which otherwise would be rejected within 25 days. The MHC tetramer staining suggested the underlying mechanisms would not be clonal deletion or anergy.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.795-801
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• 2007

Patients with Type I diabetes mellitus have been treated with porcine insulin for several decades and pigs have recently been deemed an ideal source of microencapsulated islet cells for clinical xenotransplantation. In this study, neonatal pigs were anesthetized and sacrificed prior to a pancreatectomy. Islet cells were isolated from pancreas via collagenase digestion. Islet cells were separated and collected by hand under microscopic guidance. These cells were suspended in 1.4% sodium alginate solution and encapsulated by dropping them into 1.1% calcium chloride solution and in which the round gel in size was 250-400 ${\mu}m$ in diameter. Viability of the microencapsulated islet cells cultured in medium at $37^{\circ}C$ was assessed by MTT assay. Furthermore, insulin released in response to glucose challenge was investigated using an enzyme-linked immunosorbent assay. Secretion of insulin was low in response to the basal glucose solution (4.4 mM) in medium and was significantly higher in response to the high glucose solution (16.7 mM). The viability of microencapsulated islet cells did not differ significantly over a period of 7 days; that is, the increasing pattern of insulin concentration in the culture medium after glucose stimulation interval day was similar throughout the 7 days cultivation. In summary, experimental evidences indicated that the effects of alginate-microencapsulation prolonged survival of the neonatal porcine islets in vitro cultures and the insulin response to glucose of the islets was maintained.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.249-255
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• 2015

Diabetes mellitus, the most common metabolic disorder, is divided into two types: type 1 and type 2. The essential treatment of type 1 diabetes, caused by immune-mediated destruction of ${\beta}-cells$, is transplantation of the pancreas; however, this treatment is limited by issues such as the lack of donors for islet transplantation and immune rejection. As an alternative approach, stem cell therapy has been used as a new tool. The present study revealed that bone marrowderived mesenchymal stromal cells (BM-MSCs) could be transdifferentiated into pancreatic cells by the insertion of a key gene for embryonic development of the pancreas, the pancreatic and duodenal homeobox factor 1 (PDX1). To avoid immune rejection associated with xenotransplantation and to develop a new cell-based treatment, BM-MSCs from ${\alpha}$-1,3-galactosyltransferase knockout (GalT KO) pigs were used as the source of the cells. Transfection of the EGFP-hPDX1 gene into GalT KO pig-derived BM-MSCs was performed by electroporation. Cells were evaluated for hPDX1 expression by immunofluorescence and RT-PCR. Transdifferentiation into pancreatic cells was confirmed by morphological transformation, immunofluorescence, and endogenous pPDX1 gene expression. At 3~4 weeks after transduction, cell morphology changed from spindle-like shape to round shape, similar to that observed in cuboidal epithelium expressing EGFP. Results of RT-PCR confirmed the expression of both exogenous hPDX1 and endogenous pPDX1. Therefore, GalT KO pig-derived BM-MSCs transdifferentiated into pancreatic cells by transfection of hPDX1. The present results are indicative of the therapeutic potential of PDX1-expressing GalT KO pig-derived BM-MSCs in ${\beta}-cell$ replacement. This potential needs to be explored further by using in vivo studies to confirm these findings.