| 1. |
- Jia, Xiaohui, et al.
(författare)
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Exendin-4 Increases the Expression of Hypoxia-InducibleFactor-1 in Rat Islets and Preserves the Endocrine CellVolume of Both Free and Macroencapsulated Islet Grafts
- 2012
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Ingår i: Cell Transplantation. - 0963-6897. ; 21:6, s. 1269-1283
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we evaluated the effects of exendin-4 on free and encapsulated islet grafts in a rodent model.We also investigated the role of a transcription factor, hypoxia-inducible factor-1 (HIF-1), in mediating thebeneficial effects of exendin-4. Diabetic athymic mice were transplanted with free rat islets under the kidneycapsule or with macroencapsulated rat islets SC with or without exendin-4, islet preculture (exendin-4 0.1nM for 20 h), and/or recipient treatment (IP 100 ng/day, day 0–7). The mice were followed for 4 weeks andthe graft function andβ-cell volume were evaluated. The effects of exendin-4 on islet HIF-1α mRNAand protein expression and on ATP content in a rat insulinoma cell line (INS-1E) were also examined.Preculture with exendin-4 followed by recipient treatment improved the outcome of both free (73% graftfunction vs. 26% in controls,p = 0.03) and macroencapsulated islet grafts (100% vs. 25% in controls, p =0.02). In macroencapsulated grafts, the exendin-4-treated group had significantly larger endocrine volume,less graft necrosis, and more blood vessels around the capsule. In rat islets cultured with exendin-4, HIF-1αmRNA and protein expression were significantly enhanced. ATP content was increased in exendin-4-treatedINS-1E cells under hypoxic conditions. The improved functional outcome after transplantation of a marginalislet mass with a brief initial treatment with exendin-4 is related to a larger surviving endocrine cell volume.Exendin-4 may improve islet graft resistance to hypoxia during the peritransplant period by increasing theexpression of HIF-1
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| 2. |
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Blixt, Ola, et al.
(författare)
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Anticarbohydrate antibody repertoires in patients transplanted with fetal pig islets revealed by glycan arrays
- 2009
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Ingår i: American Journal of Transplantation. - 1600-6135 .- 1600-6143. ; 9, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- Ten patients with type I diabetes were transplanted with porcine fetal islet-like cell clusters (ICC) between 1990 and 1993. A significant rise in the anti-a -Gal antibody titers was seen posttransplant, but also nona -Gal-specific antibodies were detected in some patients. We have reanalyzed the carbohydrate specificity of antibodies in the sera from seven of these patients taken before transplantation, 1, 6 and 12 months posttransplantation using a glycan array with 200 structurally defined glycans. The main findings were: (i) prepig ICC transplantation patients had antibodies reactive with terminal a -GalNAc (e.g. the Forssman antigen, but not the blood group A determinant in blood group A patients), a -Gal (except blood group B determinants in B individuals), b 3-linked Gal especially Galb 1,3GlcNAc even if terminally sulfated or sialylated, b -GlcNAc except if b 1,3-linked and oligomannosyl compounds; (ii) the titers of all carbohydrate-specific antibodies detected before transplantation rose after transplantation; (iii) the kinetics of the antibody responses differed between patients; (iv) in some patients antibodies reacting with Gala 1,3Lex and several structures terminated with Neu5Gc appeared after transplantation. In conclusion, anti-a -Gal antibodies are the predominant anticarbohydrate antibodies detected after porcine ICC transplantation, with some patients also developing Neu5Gc-specific antibodies. Their clinical significance needs to be established.
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| 7. |
- Brandhorst, Heide, 1962-, et al.
(författare)
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A new oxygen carrier for improved long-term storage of human pancreata before islet isolation
- 2010
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 89:2, s. 155-60
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pancreas oxygenation during cold storage has been established in islet isolation and transplantation to prevent ischemic tissue damage using perfluorodecalin (PFD) as hyperoxygen carrier. However, studies in humans and pigs provided conflicting results about the efficiency of PFD for pancreas oxygenation. The aim of this study was to compare PFD with a newly developed oxygen carrier composed of perfluorohexyloctane and polydimethylsiloxane 5 (F6H8S5) for long-term storage of human pancreata.METHODS: After 24-hr storage in preoxygenated PFD or F6H8S5, pancreata were processed using Liberase HI for pancreas dissociation and a Ficoll gradient for islet purification. Islet quality assessment was performed measuring glucose-stimulated insulin release, viability, islet ATP content, and posttransplant function in diabetic nude mice.RESULTS: Compared with PFD, F6H8S5 significantly increased the intrapancreatic partial oxygen pressure and islet ATP content. This corresponded to an increase of islet yield, recovery after culture, glucose stimulation index, viability, and improved graft function in diabetic nude mice.CONCLUSIONS: The present findings indicate clearly that F6H8S5 improves isolation outcome after prolonged ischemia compared with PFD. This observation seems to be related to the significant lipophilicity and almost pancreas-specific density of F6H8S5. Moreover, these characteristics facilitate pancreas shipment without using custom-made transport vessels as required for PFD.
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| 8. |
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| 9. |
- Brandhorst, Heide, 1962-, et al.
(författare)
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The importance of tryptic-like activity in purified enzyme blends for efficient islet isolation
- 2009
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 87:3, s. 370-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The isolation of islets from the human pancreas critically depends on an efficient enzyme blend. Previous studies have solely focused on the presence of collagenase and neutral protease/thermolysin. Despite improved characterization of these components, the lot-related variability in efficacy still persists suggesting that additional so far disregarded enzymes are required for efficient islet cleavage. METHODS: Varying activities of a tryptic-like enzyme were identified within collagenase NB1 lots, which were selected according to a matched ratio between tryptic-like and collagenase activity (TLA-ratio). Rat and human pancreata were processed with current standard procedures. RESULTS: Increasing the TLA-ratio from 1.3% to 10% reduced pancreas dissociation time in rats by 50% without affecting islet yield, viability, or posttransplant function in diabetic nude mice. Enhancing the TLA-ratio from 1.3% to 12.6% for human pancreas processing resulted in a significant reduction of recirculation time and increased incrementally human islet yield without affecting purity, in vitro function or recovery after culture. Optimized pancreas digestion correlated with a higher percentage of islet preparations fulfilling quality criteria for clinical transplantation. CONCLUSIONS: We conclude that TLA is an effective component that should be included in moderate amounts in enzyme blends for human islet isolation to optimize the efficiency and minimize the lot-related variability.
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| 10. |
- Caballero-Corbalán, José, et al.
(författare)
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No beneficial effect of two-layer storage compared with UW-storage on human islet isolation and transplantation
- 2007
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 84:7, s. 864-869
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Tidskriftsartikel (refereegranskat)abstract
- Background. Shipment of pancreata between distant centers is frequently associated with prolonged cold ischemia time (CIT) that leads to poorer outcomes for islet transplantation. Clinical pilot trials have indicated that oxygenation of explanted human pancreata utilizing the two-layer method (TLM) allows the use of marginal donor pancreata for islet transplantation. The present study aimed to clarify whether TLM enhances the ischemic tolerance of human pancreata. Methods. We analyzed retrospectively the outcome of 200 human islet isolations performed after TLM preservation or storage in University of Wisconsin solution (UWS). Results. Donor characteristics and digestion parameters did not vary significantly between TLM-preserved and UWS-stored pancreata. No differences were observed between experimental groups with regard to islet yield, purity, or dynamic glucose stimulation index after either short or prolonged CIT. However, CIT and stimulation index were negatively correlated in each experimental group. The isolation outcome in donors aged ≥60 years was not increased after TLM preservation when compared to UWS storage. No effect was observed regarding islet posttransplant function in recipients with established kidney grafts. Conclusions. The present study suggests that the ischemic tolerance of human pancreata cannot be extended by TLM preservation. In addition, TLM does not seem to improve the isolation outcome for pancreata from elderly donors.
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| 11. |
- Caballero-Corbalán, José, et al.
(författare)
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Using HTK for Prolonged Pancreas Preservation Prior to Human Islet Isolation
- 2012
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Ingår i: Journal of Surgical Research. - : Elsevier BV. - 1095-8673 .- 0022-4804. ; 175:1, s. 163-168
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Tidskriftsartikel (refereegranskat)abstract
- Background. Histidine-tryptophan-ketoglutarate (HTK) has been established as an alternative to University-of-Wisconsin solution (UWS) for abdominal organ preservation, but data about HTK efficiency to preserve pancreata during prolonged cold ischemia time (CIT) are conflicting. In human islet transplantation, HTK provided similar isolation outcomes after short CIT. The present study aimed to investigate whether islets can be successfully isolated from HTK-preserved pancreata after prolonged CIT compared with UWS. Materials and Methods. Sixty-four human pancreata retrieved from donors meeting criteria for kidney donation were perfused utilizing either HTK or UWS and preserved for more or less than 10 h prior to islet isolation. Along with parameters related to isolation and islet quality assessment, the dry-to-wet weight ratio was evaluated. Results. Donor-and procurement-related factors did not vary between HTK- and UWS-perfused pancreata. The dry-to-wet weight ratio was lower in HTK-preserved pancreata indicated tissue edema (21.0% +/- 3.5% versus 24.8% +/- 2.0%, P = 0.007). Isolation-related variables differed between experimental groups after prolonged CIT with respect to purified packed tissue volume (9.1 +/- 5.0 versus 17.2 +/- 8.1 mu L/g, P = 0.004) and islet yield (1910 +/- 980 versus 3150 +/- 1420 IE/g, P = 0.012). Islet purity and survival after culture were similar after HTK or UWS perfusion. The preservation solution did not affect in vitro function and transplantability of isolated islets. Conclusions. Compared with UWS, HTK has similar efficiency to preserve human pancreata for subsequent islet isolation during <10 h CIT but seems to be limited for prolonged cold storage. (C) 2012 Elsevier Inc. All rights reserved.
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| 12. |
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| 13. |
- Cabric, Sanja, et al.
(författare)
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Islet Surface Heparinization Prevents the Instant-Blood Mediated Inflammatory Reaction in Islet Transplantation
- 2007
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 2008-2015
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.
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| 14. |
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| 15. |
- Diab, Randa A H, et al.
(författare)
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Rat islets are not rejected by anti-islet antibodies in mice treated with costimulation blockade.
- 2014
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Ingår i: Xenotransplantation. - : Wiley. - 1399-3089 .- 0908-665X. ; 21:4, s. 353-66
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Tidskriftsartikel (refereegranskat)abstract
- Costimulation blockade can prevent rejection of islet xenografts in naïve but not sensitized recipients. Donor-specific antibodies (DSA) may partly explain this observation. The effect of DSA on rat islet xenograft survival in mice receiving costimulation blockade was investigated.
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| 16. |
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| 17. |
- Eriksson, Olof, et al.
(författare)
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Positron emission tomography in clinical islet transplantation
- 2009
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Ingår i: American Journal of Transplantation. - : Elsevier BV. - 1600-6135 .- 1600-6143. ; 9:12, s. 2816-2824
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Tidskriftsartikel (refereegranskat)abstract
- The fate of islets in clinical transplantation is unclear. To elude on this positron emission tomography combined with computed tomography (PET/CT) was performed for 60 min during islet transplantation in five patients receiving six transplants. A fraction of the islets (23%) were labeled with 18F-fluorodeoxyglucose ([(18)F]FDG) and carefully mixed with unlabeled islets just prior to intraportal transplantation. The peak radioactivity concentration in the liver was found at 19 min after start of islet infusion and corresponded to only 75% of what was expected, indicating that islets are lost during the transplantation procedure. No accumulation of radioactivity was found in the lungs. A nonphysiological peak of C-peptide was found in plasma during and immediately after transplantation in all subjects. Distribution in the liver was heterogeneous with wide variations in location and concentration. Islets found in areas with concentrations of >400 IEQ/cc liver tissue varied between 1% and 32% of the graft in different subjects. No side effects attributed to the PET/CT procedure were found. Clinical outcome in all patients was comparable to that previously observed indicating that the [(18)F]FDG labeling procedure did not harm the islets. The technique has potential to be used to assess approaches to enhance islet survival and engraftment in clinical transplantation.
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| 18. |
- Friberg, Andrew S, et al.
(författare)
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Transplantable functional islet mass – predictive biomarkers of graft function in islet after kidney transplanted patients
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal. Analysis of donor, islet isolation, quality control and recipient variables was undertaken in 110 islet after kidney (IAK) transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio (ΔCP/GCr). Using backward multiple regression the variables positively associated to ΔCP/GCr were islet volume transplanted (p<0.001) and glucose stimulated insulin secretion (SI) (p=0.009). Factors negatively associated to ΔCP/GCr were cold ischemia time (CIT) (p=0.002) and total tissue volume (p=0.009). Donor age, donor body mass index, number of retrieved organs from the donor, preservation solution, islet insulin content, body weight of the recipient of the islets had no influence on transplant function. The transplantable functional islet mass (TFIM), accounting for islet volume transplanted, SI, CIT, and total tissue volume explained 39% of the variance of the clinical outcome in the IAK data set. Therefore, the TFIM provides a straightforward and potent tool to guide the decision to utilize a specific islet preparation for clinical transplantation.
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| 19. |
- Friberg, Andrew S., et al.
(författare)
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Transplanted functional islet mass : donor islet preparation, and recipitent factors influence early graft function in islet-after-kidney patients
- 2012
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Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 93:6, s. 632-638
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Tidskriftsartikel (refereegranskat)abstract
- Background.The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal.Methods. Analysis of 10 donor, 7 islet isolation, 3 quality control, and 6 recipient variables was undertaken in 110 islet-after-kidney transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio ([DELTA]CP/GCr).Results.Univariate analysis yielded islet volume transplanted (Spearman r=0.360, P<0.001) and increment of insulin secretion (r=0.377, P<0.001) as variables positively associated to [DELTA]CP/GCr. A negative association to [DELTA]CP/GCr was cold ischemia time (r=-0.330, P<0.001). A linear, backward-selection multiple regression was used to obtain a model for the transplanted functional islet mass (TFIM). The TFIM model, composed of islet volume transplanted, increment of insulin secretion, cold ischemia time, and exocrine tissue volume transplanted, accounted for 43% of the variance of the clinical outcome in the islet-after-kidney data set.Conclusion.The TFIM provides a straightforward and potent tool to guide the decision to use a specific islet preparation for clinical transplantation.
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| 20. |
- Gyllström Krekula, Linda, et al.
(författare)
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What do people agree to when stating willingness to donate? : On the medical interventions enabling organ donation after death
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Purpose of the studyThe purpose of this study is to explore donor relatives’ experiences of the medical interventions enabling organ donation, as well as to examine the donor relatives’ attitudes towards donating their own organs, and whether or not their experiences have influenced their own inclination to donate.MethodsThe experiences of donor relatives were explored via in-depth interviews. The interviews covered every step from the deceased family member being struck by a severe bleeding in the brain till after the organ recovery, including the medical interventions enabling organ donation. The interviews were analysed through qualitative and quantitative content analysis.ResultsBrain death and organ donation proved to be hard to understand for many donor relatives. The prolonged interventions provided after death in order to enable organ donation misled some relatives to believe that their family member still was alive. In general, the understanding for what treatment aimed at saving the family member and what interventions aimed at maintaining organ viability was low. However, most donor relatives were either inspired to, or reinforced in their willingness to, donate their own organs after having experienced the loss of a family member who donated organs.ConclusionsThere is a need for greater transparency regarding the whole chain of events during the donation process. Yet, having experienced the donation process closely did not discourage the donor relatives from donating their own organs–but rather inspired a willingness to donate. This indicates an acceptance of the medical procedures necessary in order to enable organ donation after death.
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| 21. |
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| 23. |
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| 24. |
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| 25. |
- Johansson, Helena, et al.
(författare)
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Tissue factor produced by the endocrine cells of the islets of Langerhans is associated with a negative outcome of clinical islet transplantation
- 2005
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 54:6, s. 1755-62
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Tidskriftsartikel (refereegranskat)abstract
- There are strong indications that only a small fraction of grafts successfully engraft in clinical islet transplantation. One explanation may be the instant blood-mediated inflammatory reaction (IBMIR) elicited by tissue factor, which is produced by the endocrine cells. In the present study, we show that islets intended for islet transplantation produce tissue factor in both the transmembrane and the alternatively spliced form and that the membrane-bound form is released as microparticles often associated with both insulin and glucagon granules. A low-molecular mass factor VIIa (FVIIa) inhibitor that indirectly blocks both forms of tissue factor was shown in vitro to be a promising drug to eliminate the IBMIR. Thrombin-antithrombin complex (TAT) and FVIIa-antithrombin complex (FVIIa-AT) were measured in nine patients who together received 20 infusions of isolated human islets. Both the TAT and FVIIa-AT complexes increased rapidly within 15-60 min after infusion. When the initial TAT and FVIIa-AT levels were plotted against the increase in C-peptide concentration after 7 days, patients with an initially strong IBMIR showed no significant increase in insulin synthesis after 7 days. In conclusion, tissue factor present in both the islets and the culture medium and elicits IBMIR, which affects the function of the transplanted islets.
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| 26. |
- Korsgren, Olle, et al.
(författare)
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Optimising islet engraftment is critical for successful clinical islet transplantation
- 2008
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 51:2, s. 227-32
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Tidskriftsartikel (refereegranskat)abstract
- Clinical islet transplantation is currently being explored as a treatment for persons with type 1 diabetes and hypoglycaemia unawareness. Although 'proof-of-principle' has been established in recent clinical studies, the procedure suffers from low efficacy. At the time of transplantation, the isolated islets are allowed to embolise the liver after injection in the portal vein, a procedure that is unique in the area of transplantation. A novel view on the engraftment of intraportally transplanted islets is presented that could explain the low efficacy of the procedure.
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| 27. |
- Lagging, Eva, et al.
(författare)
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Potential living kidney donors' positive experiences of an information letter from healthcare : a descriptive qualitative study
- 2022
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Ingår i: BMC Nephrology. - : BioMed Central (BMC). - 1471-2369. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundPatients who need a live donor kidney transplant (LDKT) must often ask potential donors (PLDs) themselves. This is a difficult task and healthcare could unburden them by making this first contact, ensuring also that PLDs receive correct information. We investigated how PLDs experience receiving a letter from healthcare about LDKT, live kidney donation, and inviting them to meet with professionals to get more information.MethodsThe letter (LD-letter) was sent to a cohort of 46 individuals, from which a purposeful sample of 15 were interviewed using a semi-structured guide covering their experience of the letter, views on being approached by healthcare, and opinions on style and content. Interviews were analyzed using conventional inductive analysis.ResultsWe identified three categories of experiences: Category (1) Reflections on receiving the letter, contains three subcategories relating to how the letter did not induce pressure to donate, did not affect the PLD's relationship with the patient with kidney disease, and made the letter-receiver feel important in the transplant process; Category (2) The letter creates clarification and trust, also contains three subcategories, relating to how it clarified the voluntariness of donation and neutrality of healthcare providers with respect to the PLD's decision, elucidated the patient with kidney disease's current stage of disease (where transplantation was approaching), and unburdened patients from the responsibility of contacting PLDs on their own; Category (3) Opinions and suggestions about the letter and further communication, with four subcategories, relating to preference of a letter as the first step for communication about LDKT, suggestions on style and content, views on following up the letter, and how open meetings about LDKT were an important information source. Furthermore, 80% of the interviewees found the letter's information comprehensive, 67% found it easy to read and respectful, and 86% rated it as good or very good.ConclusionPotential donors prefer and recommend a letter as the first step for communication regarding LD. The LD-letter unburdens patients from the task of asking PLDs and stresses the voluntariness of donation, does not leave PLDs feeling coerced or lead to negative effects in their relationship with the patient.
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| 28. |
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| 29. |
- Lau, Joey, 1979-
(författare)
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Implantation-Site Dependent Differences in Engraftment and Function of Transplanted Pancreatic Islets
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transplanting pancreatic islets into the liver through the portal vein is currently the most common procedure in clinical islet transplantations for treating patients with brittle type 1 diabetes. However, most islet grafts fail within a 5-year period necessitating retransplantation. The vascular connections are disrupted at islet isolation and implanted islets depend on diffusion of oxygen and nutrients in the immediate posttransplantation period. Rapid and efficient revascularization is of utmost importance for the survival and long-term function of transplanted islets. In this thesis, the influence of the implantation microenvironment for islet engraftment and function was studied. Islets were transplanted into the liver, the renal subcapsular site or the pancreas. Islets implanted into the liver contained fewer glucagon-positive cells than islets implanted to the kidney and endogenous islets. Intraportally transplanted islets responded with insulin and glucagon release to secretagogues, but only when stimulated through the hepatic artery. Thus, the intrahepatic grafts were selectively revascularized from the hepatic artery. The vascular density in human islets transplanted into the liver of athymic mice was markedly lower when compared to human islets grafted to the kidney. Islets implanted into their physiological environment, the pancreas, were markedly better revascularized. Insulin content, glucose-stimulated insulin release, (pro)insulin biosynthesis and glucose oxidation rate were markedly decreased in transplanted islets retrieved from the liver, both when compared to endogenous and transplanted islets retrieved from the pancreas. Only minor changes in metabolic functions were observed in islets implanted into the pancreas when compared to endogenous islets. The present findings demonstrate that the microenvironment has a major impact on the engraftment of transplanted islets. Elucidating the beneficial factors that promote engraftment would improve the survival and long-term function of transplanted islets. Ultimately, islet transplantation may be provided to an increased number of patients with type 1 diabetes.
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| 30. |
- Lorant, Tomas, 1975-
(författare)
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Studies of Rejection in Experimental Xenotransplantation
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One main hurdle to xenotransplantation, i.e. transplantation between different species, is the immunological barrier that the organ meets in the recipient. The aim of this thesis was to characterise xenogeneic rejection mechanisms by using the concordant mouse-to-rat heart transplantation model.Graft-infiltrating immune cells could be isolated from both rejecting and non-rejecting grafts using ex vivo propagation, a technique based on incubation of graft biopsies in culture medium for 48 hours. The numbers of recovered T lymphocytes were considerably higher in grafts undergoing cell-mediated rejection than in grafts undergoing acute vascular rejection (AVR) or in non-rejecting transplants. Thus, ex vivo propagation should be a valuable tool for further studies of cell-mediated rejection.Cytokine patterns in the grafts, as measured by a quantitative real-time RT-PCR method, showed that AVR and cell-mediated rejection are associated with an increase of both pro-inflammatory cytokines (IL-1β and TNF-α) and more specific cytokines (IL-2, IL-10, IL-12p40 and IFN-γ). These data differed considerably from the patterns seen in the spleens of the recipients. Cell-mediated xenograft rejection was also found to be associated with a local accumulation of hyaluronan.Oral administration of xenogeneic cells stimulated a production of antibodies that could induce hyperacute rejection of cardiac xenografts when passively transferred to graft recipients. This is in contrast to several models for autoimmune diseases and allogeneic transplantation where oral administration of antigens is an effective way to induce unresponsiveness. Hence, future attempts to induce oral tolerance in xenotransplantation should be done with caution.
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| 31. |
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| 32. |
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| 33. |
- Sanner, Margareta, et al.
(författare)
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The kidney recipients' path to transplantation : A comparison between living and deceased kidney donor recipients in Stockholm, Sweden
- 2011
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 26:3, s. 1053-1057
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Much remains to be done to facilitate the transplantation process for patients with end-stage renal disease. The aim here was to explore these patients' experiences of the donation process and factors related to whether the actual donors of the recipients were living or deceased and describe which issues needed attention in a quality development project. Method. A specially constructed questionnaire was sent to 246 recipients of living and deceased kidney transplants who had been transplanted at the Karolinska University Hospital in Stockholm, Sweden. The response rate was 87%. RESULTS: Six conditions were identified as problematic:- Most living-donor kidney recipients perceived the evaluation period for the donors as too long. - Although a living donor was available, most living-donor kidney recipients had to undergo dialysis for a relatively long period. - A majority of the patients perceived it difficult to ask for a donation. Deceased-donor kidney recipients were least satisfied with the offered support in finding a living donor. - Patients perceived fear as the main reason for potential living donors to refuse donation. - About one-fourth of living-donor kidney recipients thought that the donors were abandoned by healthcare after nephrectomy. - Older patients and singles were least likely to receive a living-donor kidney. CONCLUSIONS: The problem issues outlined above should be scrutinized and improved. Checking these issues can be used in quality control when analysing living kidney donation at local and national levels.
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| 34. |
- Takahashi, Tohru, et al.
(författare)
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Multipotent mesenchymal stromal cells synergize with costimulation blockade in the inhibition of immune responses and the induction of foxp3+ regulatory T cells.
- 2014
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Ingår i: Stem cells translational medicine. - : Oxford University Press (OUP). - 2157-6564 .- 2157-6580. ; 3:12, s. 1484-94
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Tidskriftsartikel (refereegranskat)abstract
- Multipotent mesenchymal stromal cell (MSC) therapy and costimulation blockade are two immunomodulatory strategies being developed concomitantly for the treatment of immunological diseases. Both of these strategies have the capacity to inhibit immune responses and induce regulatory T cells; however, their ability to synergize remains largely unexplored. In order to study this, MSCs from C57BL/6 (H2(b)) mice were infused together with fully major histocompatibility complex-mismatched Balb/c (H2(d)) allogeneic islets into the portal vein of diabetic C57BL/6 (H2(b)) mice, which were subsequently treated with costimulation blockade for the first 10 days after transplantation. Mice receiving both recipient-type MSCs, CTLA4Ig, and anti-CD40L demonstrated indefinite graft acceptance, just as did most of the recipients receiving MSCs and CTLA4Ig. Recipients of MSCs only rejected their grafts, and fewer than one half of the recipients treated with costimulation blockade alone achieved permanent engraftment. The livers of the recipients treated with MSCs plus costimulation blockade contained large numbers of islets surrounded by Foxp3(+) regulatory T cells. These recipients showed reduced antidonor IgG levels and a glucose tolerance similar to that of naïve nondiabetic mice. Intrahepatic lymphocytes and splenocytes from these recipients displayed reduced proliferation and interferon-γ production when re-exposed to donor antigen. MSCs in the presence of costimulation blockade prevented dendritic cell maturation, inhibited T cell proliferation, increased Foxp3(+) regulatory T cell numbers, and increased indoleamine 2,3-dioxygenase activity. These results indicate that MSC infusion and costimulation blockade have complementary immune-modulating effects that can be used for a broad number of applications in transplantation, autoimmunity, and regenerative medicine.
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| 35. |
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| 36. |
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