• Archives of Plastic Surgery
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• v.48 no.1
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• pp.133-143
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• 2021

Background Extensive research has been conducted on islet transplantation as a possible cure for diabetes. Islet transplantation in the liver via the portal vein has shown remarkable results, but numerous other recipient sites are currently being investigated. We aimed to show the effectiveness of using a muscle flap as a recipient site for islet transplantation. Methods Islet cells were harvested from 12 isogenic Lewis rats, and then diabetes was induced in another 12 isogenic Lewis rats by streptozotocin injection. In six rats, 3,000 islets were transplanted into gastrocnemius muscle flaps, and in the other six rats, the same number of islets were transplanted into the gastrocnemius muscle. The transplanted islet cell function between the two groups was compared by means of blood glucose tests, glucose tolerance tests, immunohistochemistry, and real-time reverse transcription polymerase chain reaction. Results In the muscle flap group, blood glucose levels significantly decreased after islet transplantation. Blood glucose levels were significantly different between the two groups at 3 weeks after transplantation. The muscle flap group showed nearly normoglycemic results upon the glucose tolerance test, whereas the muscle group was hyperglycemic. Immunohistochemical evaluation showed positive results against insulin and glucagon in biopsies of both groups, and the islet cell density was higher in the muscle flap group. There were no statistically significant differences between the two groups in real-time reverse transcription polymerase chain reaction results. Conclusions Our results suggest that muscle flaps are promising candidates for islet cell transplantation.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.304-312
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• 2018

Regulatory T cells (Treg), known as immune-suppressors, may help modulate the immune response. In this study, we investigated the effect of Treg-derived $TGF-{\beta}1$ on pancreatic islet cell function in vitro and in vivo. One hundred eighty IEQ (islet equivalents) of pancreatic islets, the marginal amount to regulate blood glucose level after syngeneic islet transplantation in mouse type 1 diabetes (T1D) model, were co-cultured with $4{\times}10^6$ Treg cells for 48 hours. The changes in $TGF-{\beta}1$, interleukin-6 (IL-6), and insulin secretion levels were measured and analyzed among the Treg-only group, the islet-only group, and the Treg/islet co-cultured group. In the Treg/islet co-cultured group, IL-6 and insulin secretion levels were increased (P<0.0005, P<0.005) and islet viability was improved (P<0.005) compared with the islet-only group. Furthermore, after transplantation, the co-cultured islets regulated blood glucose levels efficiently in the T1D mouse model. These data suggest that Treg could improve islet functions and viability via the $TGF-{\beta}1$ secretion pathway (P<0.05~0.005), thus the use of Treg in islet transplantation should be explored further.

• Applied Microscopy
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• v.37 no.4
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• pp.249-258
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• 2007

The Pancreatic islet are the clusters of endocrine cells scattered through out the exocrine pancreas. Transplantation of a sufficient pancreatic islets can normalize blood glucose level so that may prevent devastating complications of type I diabetes(IDDM) and other side effects of the IDDM. Recently, there are several approaches to transplant sufficient pancreatic islet, and it was comprised in increase or regeneration of the endogenous $\beta$-cell mass from donor's pancreas, but relatively few studies have been devoted to the morphological characters of the isolated and 3 day cultured pancreatic islets. We investigated morphological pattern of intracellular structure of isolated and 3 day cultured pancreatic islets. The morphological characters of the pancreatic islets were observed by scanning electron microscope and transmission electron microscope, and insulin distribution of the each islets were observed by transmission electron microscope, and were labeled with insulin antibody. Intracellular structures including nuclei, mitochondria, RER, Golgi complex and many secretory granules were normally appeared in the isolated pancreatic islets which was extracted immediately dornor's pancreas, however, There is a significant morphological changes between the 3 day cultured pancreatic islets and isolated islets. 3 day cultured pancreatic islet's $\beta$-cells had normal nuclei but increased cytoplasm mass and RER and developed Golgi complex. Insulin secretory granules were decreased in numbers rather than isolated pancreatic islet. In this study, the pattern of intracellular structure variation was examined during pancreatic islet culture. Most distinct features are variation of the insulin secretory granules, and developed RER, and dilated golgi complex. Therefore, we suggested that the various change of the morphological characters on cultured pancreatic islets were responsible for the function(biosynthesis and secretion of insulin) and growth. These results were also cultured islets have greater ability to recover and maintain normoglycemia than isolated islet transplantation.

• 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.

• IMMUNE NETWORK
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• v.13 no.1
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• pp.16-24
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• 2013

CTLA-4Ig is regarded as an inhibitory agent of the T cell proliferation via blocking the costimulatory signal which is essential for full T cell activation. To improve applicability, we developed the CTLA-4Ig-CTKC in which the c-terminal lysine had been replaced by cysteine through single amino acid change. The single amino acid mutation of c-terminus of CTLA-4Ig was performed by PCR and was checked by in vitro transcription and translation. DNA construct of mutant form was transfected to Chinese hamster ovary (CHO) cells by electroporation. The purified proteins were confirmed by Western blot and B7-1 binding assay for their binding ability. The suppressive capacity of CTLA-4Ig-CTKC was evaluated by the mixed lymphocyte reaction (MLR) and in the allogeneic pancreatic islet transplantation model. CTLA-4Ig-CTKC maintained binding ability to B7-1 molecule and effectively inhibits T cell proliferation in MLR. In the murine allogeneic pancreatic islet transplantation, short-term treatment of CTLA-4Ig-CTKC prolonged the graft survival over 100 days. CTLA-4Ig-CTKC effectively inhibits immune response both in MLR and in allogeneic islet transplantation model, indicating that single amino acid mutation does not affect the inhibitory function of CTLA-4Ig. CTLA-4Ig-CTKC can be used in vehicle-mediated drug delivery system such as liposome conjugation.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.695-698
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• 2000

We studied the viability and function of islet with monomethoxy polyethylene glycol (mPEG) grafted onto its membrane. Islets were isolated from rat and were repeatedly reacted with activated mPEG (mw 5000) in order to increase grafting density. The density of grafted PEG on the islet membrane was confirmed by Fluorescein-PEG-NHS. An assessment of islet viability using AO / PI staining method showed that multiple PEGylation did not reduce islet viability. The function of PEG grafted islets was evaluated by measuring released insulin from islets. Insulin secreted from the PEGylated islets for 1 h did not show any significant difference compared to control (non-PEGylated) islets. In addition, PEGylated islets responded in the same pattern as control islets in the perifusion test.

• IMMUNE NETWORK
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• v.13 no.6
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• pp.235-239
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• 2013

Encapsulation of tissue has been an area of intense research with a myriad number of therapeutic applications as diverse as cancer, tissue regeneration, and diabetes. In the case of diabetes, transplantation of pancreatic islets of Langerhans containing insulin-producing beta cells has shown promise toward a cure. However, anti-rejection therapy that is needed to sustain the transplanted tissue has numerous adverse effects, and the islets might still be damaged by immune processes. Furthermore, the profound scarcity of healthy human donor organs restricts the availability of islets for transplant. Islet encapsulation allows the protection of this tissue without the use of toxic medications, while also expanding the donor pool to include animal sources. Before the widespread application of this therapy, there are still issues that need to be resolved. There are many materials that can be used, differing shapes and sizes of capsules, and varied sources of islets to name a few variables that need to be considered. In this review, the current options for capsule generation, past animal and human studies, and future directions in this area of research are discussed.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.153-165
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• 2019

Objective : Spinal cord injury (SCI) is a very serious health problem, usually caused by a trauma and accompanied by elevated levels of inflammation indicators. Stem cell-based therapy is promising some valuable strategies for its functional recovery. Nestin-positive progenitor and/or stem cells (SC) isolated from pancreatic islets (PI) show mesenchymal stem cell (MSC) characteristics. For this reason, we aimed to analyze the effects of rat pancreatic islet derived stem cell (rPI-SC) delivery on functional recovery, as well as the levels of inflammation factors following SCI. Methods : rPI-SCs were isolated, cultured and their MSC characteristics were determined through flow cytometry and immunofluorescence analysis. The experimental rat population was divided into three groups : 1) laminectomy & trauma, 2) laminectomy & trauma & phosphate-buffered saline (PBS), and 3) laminectomy+trauma+SCs. Green fluorescent protein (GFP) labelled rPI-SCs were transplanted into the injured rat spinal cord. Their motilities were evaluated with Basso, Beattie and Bresnahan (BBB) Score. After 4-weeks, spinal cord sections were analyzed for GFP labeled SCs and stained for vimentin, $S100{\beta}$, brain derived neurotrophic factor (BDNF), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase), vascular endothelial growth factor (VEGF) and proinflammatory (interleukin [IL]-6, transforming growth factor $[TGF]-{\beta}$, macrophage inflammatory protein [MIP]-2, myeloperoxidase [MPO]) and anti-inflammatory (IL-1 receptor antagonis) factors. Results : rPI-SCs were revealed to display MSC characteristics and express neural and glial cell markers including BDNF, glial fibrillary acidic protein (GFAP), fibronectin, microtubule associated protein-2a,b (MAP2a,b), ${\beta}3$-tubulin and nestin as well as anti-inflammatory prostaglandin E2 receptor, EP3. The BBB scores showed significant motor recovery in group 3. GFP-labelled cells were localized on the injury site. In addition, decreased proinflammatory factor levels and increased intensity of anti-inflammatory factors were determined. Conclusion : Transplantation of PI-SCs might be an effective strategy to improve functional recovery following spinal cord trauma.

• Journal of Pharmaceutical Investigation
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• v.16 no.3
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• pp.89-100
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• 1986

Although insulin has been available for the treatment of diabetes mellitus for more than half a centry, the deficiency of conventional insulin therapy for diabetic patients have, to this date, not been satisfactorily overcome by any method. The development of potential delivery systems for insulin is highly important to prevent excessive fluctuation of plasma glucose levels, which results in long term complications in the diabetic. There are three major approaches toward development of glucose responding insulin delivery systems: A bioengineering approach is to devise mechanical components capable of releasing insulin in amounts appropriate to varying blood-glucose requirements. A biological approach relies upon cultured, living pancreatic beta cells encapsulated to constitute an insulin delivery unit. A biochemical approach is to synthesize a stable and biologically active glycosylated insulin that is complementary to the binding sites of lectin. This paper will cover several specific areas, including pancreatic transplantation(total or isolated islet cells), artificial pancreases(bioengineering or biological approach), controlled delivery system, glucose sensitive membrane systems, and a self-regulating insulin delivery system.

• 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.