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Carlsson PO, Mattsson G. Oxygen Tension and Blood Flow in Relation to Revascularization in Transplanted Adult and Fetal Rat Pancreatic Islets. Cell Transplant 2017. [DOI: 10.3727/000000002783985251] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We have previously recorded a decreased oxygen tension and blood flow in syngeneically transplanted rat pancreatic islets. The present study related measurements of oxygen tension and blood flow to the vascular density in such grafts implanted beneath the renal capsule. We also evaluated whether transplanted fetal islets are better revascularized than adult islets, and if the degree of revascularization is directly related to the islet vascular endothelial growth factor (VEGF) production. Tissue pO2 was measured using Clark microelectrodes, whereas islet graft blood flow was measured with laser-Doppler flowmetry. The vascular density of endogenous and transplanted islets was quantified in histological specimens stained with the lectin Bandeiraea simplicifolia (BS-1). Tissue pO2 in the transplanted adult and fetal islet grafts was similar and markedly lower than in the endogenous islets. The blood perfusion of both the adult and fetal islet grafts was 60–65% of that in the renal cortex. Administration of d-glucose did not affect tissue pO2 in either the endogenous or transplanted islets, nor graft blood perfusion. The number of capillaries found in the transplanted adult and fetal islets was similar and markedly lower than in endogenous islets. However, in the connective tissue stroma, which constituted ~20% of all islet grafts, the vascular density was higher than in the corresponding endocrine parts of these grafts. Incubated adult islets released higher amounts of VEGF than fetal islets. In conclusion, the previously described low oxygen tension of syngeneically transplanted adult rat islets is related to a low vascular density. Similar low oxygen tension and vascular density are seen in grafted fetal islets. The amount of VEGF production does not correlate to the degree of revascularization of the grafts.
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Affiliation(s)
- Per-Ola Carlsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Göran Mattsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Uzunalli G, Tumtas Y, Delibasi T, Yasa O, Mercan S, Guler MO, Tekinay AB. Improving pancreatic islet in vitro functionality and transplantation efficiency by using heparin mimetic peptide nanofiber gels. Acta Biomater 2015; 22:8-18. [PMID: 25931015 DOI: 10.1016/j.actbio.2015.04.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/29/2022]
Abstract
Pancreatic islet transplantation is a promising treatment for type 1 diabetes. However, viability and functionality of the islets after transplantation are limited due to loss of integrity and destruction of blood vessel networks. Thus, it is important to provide a proper mechanically and biologically supportive environment for enhancing both in vitro islet culture and transplantation efficiency. Here, we demonstrate that heparin mimetic peptide amphiphile (HM-PA) nanofibrous network is a promising platform for these purposes. The islets cultured with peptide nanofiber gel containing growth factors exhibited a similar glucose stimulation index as that of the freshly isolated islets even after 7 days. After transplantation of islets to STZ-induced diabetic rats, 28 day-long monitoring displayed that islets that were transplanted in HM-PA nanofiber gels maintained better blood glucose levels at normal levels compared to the only islet transplantation group. In addition, intraperitoneal glucose tolerance test revealed that animals that were transplanted with islets within peptide gels showed a similar pattern with the healthy control group. Histological assessment showed that islets transplanted within peptide nanofiber gels demonstrated better islet integrity due to increased blood vessel density. This work demonstrates that using the HM-PA nanofiber gel platform enhances the islets function and islet transplantation efficiency both in vitro and in vivo.
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Affiliation(s)
- Gozde Uzunalli
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
| | - Yasin Tumtas
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
| | - Tuncay Delibasi
- Pancreas Islet Cell Research Center, Ankara Diskapi Yildirim Beyazit Training and Research Hospital Etlik Polyclinic, Department of Endocrinology and Metabolism, Ankara 06800, Turkey; Hacettepe University, School of Medicine, Department of Endocrinology, Ankara 06100, Turkey.
| | - Oncay Yasa
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
| | - Sercan Mercan
- Pancreas Islet Cell Research Center, Ankara Diskapi Yildirim Beyazit Training and Research Hospital Etlik Polyclinic, Department of Endocrinology and Metabolism, Ankara 06800, Turkey; Gazi University, Faculty of Science, Department of Chemistry, Ankara 06560, Turkey
| | - Mustafa O Guler
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey.
| | - Ayse B Tekinay
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey.
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Nishimura R, Nishioka S, Fujisawa I, Shiku H, Shimada M, Sekiguchi S, Fujimori K, Ushiyama A, Matsue T, Ohuchi N, Satomi S, Goto M. Tacrolimus inhibits the revascularization of isolated pancreatic islets. PLoS One 2013; 8:e56799. [PMID: 23613708 PMCID: PMC3629082 DOI: 10.1371/journal.pone.0056799] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 01/16/2013] [Indexed: 01/10/2023] Open
Abstract
AIMS Immunosuppressive drugs could be crucial factors for a poor outcome after islet allotransplantation. Unlike rapamycin, the effects of tacrolimus, the current standard immunosuppressant used in islet transplantation, on graft revascularization remain unclear. We examined the effects of tacrolimus on islet revascularization using a highly sensitive imaging system, and analyzed the gene expression in transplanted islets by introducing laser microdissection techniques. METHODS Islets isolated from C57BL/6-Tg (CAG-EGFP) mice were transplanted into the nonmetallic dorsal skinfold chamber on the recipients. Balb/c athymic mice were used as recipients and were divided into two groups: including a control group (n = 9) and tacrolimus-treated group (n = 7). The changes in the newly-formed vessels surrounding the islet grafts were imaged and semi-quantified using multi-photon laser-scanning microscopy and a Volocity system. Gene expression in transplanted islets was analyzed by the BioMark dynamic system. RESULTS The revascularization process was completed within 14 days after pancreatic islet transplantation at subcutaneous sites. The newly-formed vascular volume surrounding the transplanted islets in the tacrolimus-treated group was significantly less than that in the control group (p<0.05). Although the expression of Vegfa (p<0.05) and Ccnd1 (p<0.05) was significantly upregulated in the tacrolimus-treated group compared with that of the control group, no differences were observed between the groups in terms of other types of gene expression. CONCLUSIONS The present study demonstrates that tacrolimus inhibits the revascularization of isolated pancreatic islets without affecting the characteristics of the transplanted grafts. Further refinements of this immunosuppressive regimen, especially regarding the revascularization of islet grafts, could improve the outcome of islet allotransplantation.
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Affiliation(s)
- Ryuichi Nishimura
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
| | - Sho Nishioka
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
| | - Ikuma Fujisawa
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
| | - Hitoshi Shiku
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
| | - Miki Shimada
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan
| | - Satoshi Sekiguchi
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
| | - Keisei Fujimori
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
| | - Akira Ushiyama
- Department of Environmental Health, National Institute of Public Health, Wako, Japan
| | - Tomokazu Matsue
- WorldPremier InternationalResearch Center Initiative Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Noriaki Ohuchi
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
| | - Susumu Satomi
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
| | - Masafumi Goto
- Division of Advanced Surgical Science and Technology, Tohoku University, Sendai, Japan
- New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan
- * E-mail:
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Leung KK, Liang J, Ma MT, Leung PS. Angiotensin II type 2 receptor is critical for the development of human fetal pancreatic progenitor cells into islet-like cell clusters and their potential for transplantation. Stem Cells 2012; 30:525-36. [PMID: 22162314 DOI: 10.1002/stem.1008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Local renin-angiotensin systems (RASs) regulate the differentiation of tissue progenitors. However, it is not known whether such systems can regulate the development of pancreatic progenitor cells (PPCs). To address this issue, we characterized the expression profile of major RAS components in human fetal PPC preparations and examined their effects on the differentiation of PPCs into functional islet-like cell clusters (ICCs). We found that expression of RAS components was highly regulated throughout PPC differentiation and that locally generated angiotensin II (Ang II) maintained PPC growth and differentiation via Ang II type 1 and type 2 (AT(1) and AT(2)) receptors. In addition, we observed colocalization of AT(2) receptors with critical β-cell phenotype markers in PPCs/ICCs, as well as AT(2) receptor upregulation during differentiation, suggesting that these receptors may regulate β-cell development. In fact, we found that AT(2) , but not AT(1) , receptor was a key mediator of Ang II-induced upregulation of transcription factors important in β-cell development. Furthermore, lentivirus-mediated knockdown of AT(2) receptor suppressed the expression of these transcription factors in ICCs. Transplantation of AT(2) receptor-depleted ICCs into immune-privileged diabetic mice failed to ameliorate hyperglycemia, implying that AT(2) receptors are indispensable during ICC maturation in vivo. These data strongly indicate that a local RAS is involved in governing the functional maturation of pancreatic progenitors toward the endocrine lineage.
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Affiliation(s)
- Kwan Keung Leung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
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Abstract
Under physiological conditions and in the pathogenesis of diabetes mellitus systemic influences play a substantial role for function and survival of cells of the islet of Langerhans. Therefore, in vivo studies to understand islet biology are indispensible and imaging techniques are increasingly used for this purpose. Among the diverse imaging modalities currently only laser scanning microscopy (LSM) allows resolution and visualization of individual cells and cellular processes. To overcome limited tissue penetration and working distance of LSM and enable in vivo investigations of islet cell physiology, various experimental approaches have been developed. Especially, the recently developed imaging platforms have significantly improved the possibility to study islets at a cellular level in vivo, and provided novel insight into islet biology in health and disease. The various approaches, their applications, and reported results, as well as their limitations are reviewed in this article.
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Affiliation(s)
- Stephan Speier
- Center for Regenerative Therapies Dresden and Paul Langerhans Institute Dresden, School of Medicine, Dresden University of Technology, 01307 Dresden, Germany.
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Testicular Sertoli cells influence the proliferation and immunogenicity of co-cultured endothelial cells. Biochem Biophys Res Commun 2011; 404:829-33. [DOI: 10.1016/j.bbrc.2010.12.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 12/15/2010] [Indexed: 11/22/2022]
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Cooperative signaling for angiogenesis and neovascularization by VEGF and HGF following islet transplantation. Transplantation 2010; 90:725-31. [PMID: 20714284 DOI: 10.1097/tp.0b013e3181ef8a63] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Delayed angiogenesis remains a significant challenge to the survival of transplanted islets. In this study, using a murine model of subcutaneous islet transplantation with matrigel basement membrane matrix, we determined the role of the proangiogenic growth factors in enhancing the islet engraftment. METHODS BALB/c islets were transplanted subcutaneously in growth factor reduced (GFR) or growth factor supplemented (GFS) matrigel into diabetic severe combined immunodeficient mice. GFS matrigel was prepared by supplementing GFR with proangiogenic factors, vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). The functioning grafts were harvested at 15 days and vessel formation was analyzed histopathologically. RESULTS Our results demonstrate that suboptimal (250) islet equivalents in GFS-VEGF+HGF were able to restore normoglycemia, whereas those transplanted in GFR failed to reverse diabetes. Histopathology of the GFS-VEGF+HGF graft revealed 12±3 blood vessels per field, whereas GFR, GFS-VEGF, and GFS-HGF grafts had only 3±1, 6±2, and 4±1 blood vessels, respectively. Insulin staining demonstrated increased number of islets in matrigel supplemented with VEGF and HGF. Protein and mRNA analysis demonstrated enhanced intercellular adhesion molecule and vascular cell adhesion molecule within the islets when supplemented with both VEGF+HGF suggesting stable blood vessel formation. Transcription factors focal adhesion kinase phosphorylation and extracellular signal-regulated kinase1/2 phosphorylation were also increased (8-fold and 4.6-fold, respectively) when both the growth factors were present. There was weak expression of transcription factors when VEGF or HGF were supplemented alone. CONCLUSION We conclude that proangiogenic growth factors, VEGF and HGF, synergistically enhance angiogenesis after islet transplantation leading to stable engraftment.
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Ridgway D, Manas D, Shaw J, White S. Preservation of the donor pancreas for whole pancreas and islet transplantation. Clin Transplant 2010; 24:1-19. [DOI: 10.1111/j.1399-0012.2009.01151.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Gunawardana SC, Benninger RKP, Piston DW. Subcutaneous transplantation of embryonic pancreas for correction of type 1 diabetes. Am J Physiol Endocrinol Metab 2009; 296:E323-32. [PMID: 19066321 PMCID: PMC2645017 DOI: 10.1152/ajpendo.90544.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 12/04/2008] [Indexed: 01/14/2023]
Abstract
Islet transplantation is a promising therapeutic approach for type 1 diabetes. However, current success rates are low due to progressive graft failure in the long term and inability to monitor graft development in vivo. Other limitations include the necessity of initial invasive surgery and continued immunosuppressive therapy. We report an alternative transplantation strategy with the potential to overcome these problems. This technique involves transplantation of embryonic pancreatic tissue into recipients' subcutaneous space, eliminating the need for invasive surgery and associated risks. Current results in mouse models of type 1 diabetes show that embryonic pancreatic transplants in the subcutaneous space can normalize blood glucose homeostasis and achieve extensive endocrine differentiation and vascularization. Furthermore, modern imaging techniques such as two-photon excitation microscopy (TPEM) can be employed to monitor transplants through the intact skin in a completely noninvasive manner. Thus, this strategy is a convenient alternative to islet transplantation in diabetic mice and has the potential to be translated to human clinical applications with appropriate modifications.
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Affiliation(s)
- Subhadra C Gunawardana
- Dept. of Molecular Physiology and Biophysics, Vanderbilt Univ. School of Medicine, Nashville, TN 37232, USA.
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Janakiraman V, Mathur K, Baskaran H. Optimal planar flow network designs for tissue engineered constructs with built-in vasculature. Ann Biomed Eng 2007; 35:337-47. [PMID: 17203399 PMCID: PMC2613654 DOI: 10.1007/s10439-006-9235-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 11/14/2006] [Indexed: 11/28/2022]
Abstract
Convective delivery of nutrients is important to enhance mass transport within tissue engineered (TE) products. Depending on the target tissue, an ideal TE product will have an integrated microvasculature that will eliminate mass transport limitations that can occur during product growth in vitro and integration in vivo. A synthetic approach to develop microvasculature involves development of network designs with efficient mass transfer characteristics. In this paper, utilizing a planar bifurcating network as a basis, we develop an approach to design optimal flow networks that have maximum mass transport efficiency for a given pressure drop. We formulated the optimization problem for a TE skin product, incorporating two types of duct flow, rectangular and square, and solved using a generalized reduced gradient algorithm. Under the conditions of this study, we found that rectangular ducts have superior mass transport characteristics than square ducts. Microvascular area per volume values obtained in this work are significantly greater than those reported in the literature. We discuss the effect of network variables such as porosity and generations on the optimal designs. This research forms the engineering basis for the rational development of TE products with built-in microvasculature and will pave the way to design complex flow networks with optimal mass transfer characteristics.
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Affiliation(s)
- Vijayakumar Janakiraman
- Department of Chemical Engineering, Case Western Reserve University, 126 Bingham Building, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Narang AS, Mahato RI. Biological and Biomaterial Approaches for Improved Islet Transplantation. Pharmacol Rev 2006; 58:194-243. [PMID: 16714486 DOI: 10.1124/pr.58.2.6] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Islet transplantation may be used to treat type I diabetes. Despite tremendous progress in islet isolation, culture, and preservation, the clinical use of this modality of treatment is limited due to post-transplantation challenges to the islets such as the failure to revascularize and immune destruction of the islet graft. In addition, the need for lifelong strong immunosuppressing agents restricts the use of this option to a limited subset of patients, which is further restricted by the unmet need for large numbers of islets. Inadequate islet supply issues are being addressed by regeneration therapy and xenotransplantation. Various strategies are being tried to prevent beta-cell death, including immunoisolation using semipermeable biocompatible polymeric capsules and induction of immune tolerance. Genetic modification of islets promises to complement all these strategies toward the success of islet transplantation. Furthermore, synergistic application of more than one strategy is required for improving the success of islet transplantation. This review will critically address various insights developed in each individual strategy and for multipronged approaches, which will be helpful in achieving better outcomes.
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Affiliation(s)
- Ajit S Narang
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, 26 S. Dunlap St., Feurt Building, Room 413, Memphis, TN 38163, USA
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Olsson R, Carlsson PO. Better vascular engraftment and function in pancreatic islets transplanted without prior culture. Diabetologia 2005; 48:469-76. [PMID: 15696296 DOI: 10.1007/s00125-004-1650-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Accepted: 11/07/2004] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Recent studies suggest that donor endothelial cells may contribute to islet graft revascularisation. Since islet endothelial cells disappear during culture, we hypothesised that transplantation of islets without prior culture is beneficial for their engraftment. METHODS Cultured (4-7 days) or freshly isolated islets (<4 h after donor pancreas extirpation) were syngeneically transplanted into Wistar-Furth rats and C57Bl/6 mice beneath the renal capsule. Islet graft revascularisation was evaluated by measuring vascular density, blood flow and tissue oxygen tension. Islet graft function was investigated by a minimal islet mass model in inbred mice (C57Bl/6). RESULTS Four days after implantation, the partial pressure of oxygen (pO2) in the transplanted cultured islets was less than 10 mmHg (1.33 kPa), but tended to be higher in grafts composed of freshly isolated islets. The pO2 in the grafts of freshly isolated islets had more than doubled 4 weeks later, whereas the pO2 in the grafts of cultured islets remained at values similar to those recorded 4 days after transplantation. Transplanted freshly isolated islets also had a higher vascular density than transplanted cultured islets (approximately 40 vs approximately 25% of that in endogenous islets) when investigated 1 month post-implantation. When applying a minimal islet mass model in inbred mice, 200 freshly isolated islets cured alloxan-diabetic mice in all cases, whereas only 33% of the group receiving similar numbers of cultured islets were cured. CONCLUSIONS/INTERPRETATION Transplantation of pancreatic islets without prior culture is beneficial for their vascular engraftment and function.
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Affiliation(s)
- R Olsson
- Department of Medical Cell Biology, Uppsala University, Husargatan 3, Box 571, 751 23, Uppsala, Sweden.
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Barshes NR, Wyllie S, Goss JA. Inflammation-mediated dysfunction and apoptosis in pancreatic islet transplantation: implications for intrahepatic grafts. J Leukoc Biol 2005; 77:587-97. [PMID: 15728243 DOI: 10.1189/jlb.1104649] [Citation(s) in RCA: 252] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Recent advances in clinical protocols have improved the outcomes of pancreatic islet transplantation (PIT), yet PIT recipients typically require pancreatic islet grafts derived from multiple donors to achieve insulin independence. This along with experimental models of syngeneic PIT, showing that up to 60% of pancreatic islet tissue undergoes apoptosis within the first several days post-transplantation, strongly suggest the involvement of nonalloantigen-specific, inflammatory events in partial destruction of the graft following PIT. Interleukin-1beta appears to be among the most important inflammatory mediators, causing pancreatic islet dysfunction and apoptosis through the up-regulation of inducible nitric oxide (NO) synthase and cyclooxygenase-2. Kupffer cells secrete many molecules, including cytokines, NO, and free radicals, which are known to be directly toxic to the pancreatic islets, and depletion or inhibition of Kupffer cells improves outcomes following experimental PIT. Immediately after transplantation, the pancreatic islets are perfused only by portal vein blood until the process of angiogenesis restores arterial blood flow some 7-10 days later. This delayed vascularization may have implications for the expression of leukocyte adhesion molecules, the effects of free radicals, and the role of ischemia-reperfusion injury. Finally, in the immediate post-transplant period, hepatocytes may contribute to pancreatic islet injury through the production of NO. This paper reviews literature regarding the inflammatory events that follow PIT as well as the pathogenesis of diabetes and the pathophysiology of hepatic ischemia-reperfusion and their relation to the survival and function of intrahepatic pancreatic islet grafts.
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Affiliation(s)
- Neal R Barshes
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, 6550 Fannin, Suite 1628, Houston, TX 77030, USA
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Moore WV, Bieser K, Geng Z, Tong PY, Kover K. Decreased survival of islet allografts in rats with advanced chronic complications of diabetes. Cell Transplant 2003; 11:707-13. [PMID: 12518897 DOI: 10.3727/000000002783985369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Successful islet transplantation has been possible in experimental animals in contrast to humans. One difference between animal models of diabetes and human islet transplantation is the presence of advanced chronic complications in humans. Even longer-term follow-up of islet transplantation in humans according to the Edmonton protocol suggests that advanced chronic complications may adversely affect allograft survival with the glucocorticoid-free immunosuppressive regimen as well. We developed a rat model of chronic complications of diabetes and compared islet allograft survival in rats with advanced chronic complications to age-matched control rats with acute onset diabetes. Islets were transplanted at either the renal supcapsular, intrahepatic, or intramuscular location. The survival of islet allografts in rats with chronic complications was decreased at all sites compared with the age-matched controls. The best survival in the rats with advanced chronic complications occurred at the renal subcapsular site. Blood sugar measurements indicated impaired glucose tolerance in most of the rats with chronic complications and surviving renal subcapsular islet allograft. Histological and gross examination of the surviving renal subcapsular islet allografts indicated disordered angiogenesis in the rats with chronic complications. Rats with successful intrahepatic islet allografts and the respective age-matched controls had comparable blood sugars. Survival of islet allografts at the intramuscular site was poor in rats with chronic complications or acute onset diabetes. We conclude that the structural or metabolic abnormalities associated with chronic poor control of diabetes impair islet allograft survival and function. This should be considered as a possible explanation for failure of islet allograft survival in human islet transplantation.
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MESH Headings
- Animals
- Blood Glucose/immunology
- Chronic Disease
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/immunology
- Diabetes Mellitus, Experimental/therapy
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/immunology
- Diabetes Mellitus, Type 1/therapy
- Disease Models, Animal
- Disease Progression
- Glucose Tolerance Test
- Graft Survival/immunology
- Graft vs Host Disease/immunology
- Islets of Langerhans/cytology
- Islets of Langerhans/immunology
- Islets of Langerhans Transplantation/adverse effects
- Islets of Langerhans Transplantation/immunology
- Islets of Langerhans Transplantation/methods
- Kidney/anatomy & histology
- Kidney/immunology
- Kidney/surgery
- Liver/anatomy & histology
- Liver/immunology
- Liver/surgery
- Neovascularization, Pathologic/immunology
- Neovascularization, Pathologic/pathology
- Rats
- Rats, Inbred F344
- Transplantation Tolerance/immunology
- Treatment Failure
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Affiliation(s)
- Wayne V Moore
- Department of Endocrinology at The Children's Mercy Hospital and University of Missouri-Kansas City, Kansas City, MO 64108, USA.
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Carlsson PO, Palm F. Oxygen tension in isolated transplanted rat islets and in islets of rat whole-pancreas transplants. Transpl Int 2002. [DOI: 10.1111/j.1432-2277.2002.tb00112.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
An adequate revascularization is crucial for islet survival and function after transplantation. Previous studies have suggested that islet revascularization is concluded within 14 days after transplantation. We investigated if the vascular density of transplanted islets and endogenous pancreatic islets differs. Cultured islets were syngeneically transplanted into the kidney, liver, or spleen of C57BL/6 mice. One month later, the graft-bearing organ was removed, and histological specimens were prepared and stained for endothelium with the lectin Bandeiraea simplicifolia. Pancreata from nontransplanted control animals were prepared similarly. Uniform staining of endothelium within the grafts and endogenous islets was obtained. The vascular density was markedly decreased in transplanted islets at all implantation sites, but preferentially in islets implanted into the spleen. The vascular density in the connective tissue surrounding the transplanted islets was very high compared with that of graft intra-islet capillaries. A much lower vascular density was detected in connective tissue surrounding implanted microspheres of a size similar to the islets, which suggests that the islets per se induced blood vessel formation in their vicinity. We conclude that the vascular density in revascularized transplanted islets is markedly decreased compared with endogenous islets. This has potential implications for islet graft metabolism and function.
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Affiliation(s)
- Göran Mattsson
- Department of Medical Cell Biology, Biomedical Center, Uppsala University, Uppsala, Sweden.
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Abstract
The term "bioartificial endocrine pancreas" (BEP) was introduced by Anthony Sun in 1980. It was in 1968, however, that Thomas Chang proposed the use of microencapsulated islets as artificial beta-cells. By applying a semipermeable membrane on the top of microcapsules, a system can be produced that is impermeable to viable islet cells and large effector molecules of the immune system, thus providing a protection for transplanted islets against rejection. Since then, the term BEP has not often appeared in papers. Instead, the term "bioartificial pancreas" (BAP) has gained widespread use. In a broader sense, BAP would include an application of suitable endocrine cells and protective polymeric vehicles, but not necessarily providing a filtration barrier of precisely defined properties (e.g., cells injected into a gel of hyaluronate).
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Affiliation(s)
- A Prokop
- Chemical Engineering Department, Vanderbilt University, Nashville, TN 37235, USA.
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Carlsson PO, Palm F, Andersson A, Liss P. Chronically decreased oxygen tension in rat pancreatic islets transplanted under the kidney capsule. Transplantation 2000; 69:761-6. [PMID: 10755523 DOI: 10.1097/00007890-200003150-00015] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND A factor of potential importance in the failure of islet grafts is poor or inadequate engraftment of the islets in the implantation organ. This study measured the oxygen tension and blood perfusion in 1-, 2-, and 9-month-old islet grafts. METHODS The partial pressure of oxygen was measured in pancreatic islets transplanted beneath the renal capsule of diabetic and nondiabetic recipient rats with a modified Clark electrode (outer tip diameter 2-6 microm). The size of the graft (250 islets) was by purpose not large enough to cure the diabetic recipients. The oxygen tension in islets within the pancreas was also recorded. Blood perfusion was measured with the laser-Doppler technique. RESULTS Within native pancreatic islets, the partial pressure of oxygen was approximately 40 mm Hg (n=8). In islets transplanted to nondiabetic animals, the oxygen tension was approximately 6-7 mm Hg 1, 2, and 9 months posttransplantation. No differences could be seen between the different time points after transplantation. In the diabetic recipients, an even more pronounced decrease in graft tissue oxygen tension was recorded. The mean oxygen tension in the superficial renal cortex surrounding the implanted islets was similar in all groups (approximately 15 mm Hg). Intravenous administration of glucose (0.1 gxkg(-1)x min(-1)) did not affect the oxygen tension in any of the investigated tissues. The islet graft blood flow was similar in all groups, measuring approximately 50% of the blood flow in the kidney cortex. CONCLUSION The oxygen tension in islets implanted beneath the kidney capsule is markedly lower than in native islets up to 9 months after transplantation. Moreover, persistent hyperglycemia in the recipient causes an even further decrease in graft oxygen tension, despite similar blood perfusion. To what extent this may contribute to islet graft failure remains to be determined.
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Affiliation(s)
- P O Carlsson
- Department of Medical Cell Biology, Uppsala University, Sweden
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