Intravenous glycine improves survival in rat liver transplantation.
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In situ manipulation by touching, retracting, and moving liver lobes gently during harvest dramatically reduces survival after transplantation (P. Schemmer, R. Schoonhoven, J. A. Swenberg, H. Bunzendahl, and R. G. Thurman. Transplantation 65: 1015-1020, 1998). The development of harvest-dependent graft injury upon reperfusion can be prevented with GdCl3, a rare earth metal and Kupffer cell toxicant, but it cannot be used in clinical liver transplantation because of its potential toxicity. Thus the effect of glycine, which prevents activation of Kupffer cells, was assessed here. Minimal dissection of the liver for 12 min plus 13 min without manipulation had no effect on survival (100%). However, gentle manipulation decreased survival to 46% in the control group. Furthermore, serum transaminases and liver necrosis were elevated 4- to 12-fold 8 h after transplantation. After organ harvest, the rate of entry and exit of fluorescein dextran, a dye confined to the vascular space, was decreased about twofold, indicating disturbances in the hepatic microcirculation. Pimonidazole binding, which detects hypoxia, increased about twofold after organ manipulation, and Kupffer cells isolated from manipulated livers produced threefold more tumor necrosis factor-alpha after lipopolysaccharide than controls. Glycine given intravenously to the donor increased the serum glycine concentration about sevenfold and largely prevented the effect of gentle organ manipulation on all parameters studied. These data indicate for the first time that pretreatment of donors with intravenous glycine minimizes reperfusion injury due to organ manipulation during harvest and after liver transplantation. (+info)
Effects of a phosphate buffered extracellular (Ep4) solution in preservation and reperfusion injury in the canine liver.
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The Ep4 solution, a phosphate buffered extracellular-type solution, is effective in canine lung transplantation following a 96-hour hypothermic (4 degrees C) preservation. In this experiment, we used this solution for liver preservation followed by transplantation. We compared the Ep4 solution with the lactated Ringer's (LR) and the Collins' M (CM) solution (a phosphate buffered intracellular-type solution) in two studies, 1) 48-hour liver preservation, and 2) orthotopic liver transplantation after 5-hour preservation. In the preservation study, purine nucleoside phosphorylase (PNP) levels as a marker of endothelial damage, and alanine aminotransferase (ALT) levels were significantly lower in the livers immersed into the Ep4 solution than in those immersed into other solutions at 36 and 48 hours after preservation. Microscopically, the endothelial injury occurred 24 hours after preservation in the CM solution, and 36 hours after preservation in the LR and Ep4 solutions. In the transplantation study, serum PNP and ALT levels in the livers immersed in Ep4 solution showed a lower tendency compared with those in other solutions at the time of reperfusion, but the histological differences among three groups were not apparent. The present study suggests that the liver can be stored better for a longer time using Ep4 solution than using LR and CM solutions. (+info)
A study on continuous low-flow perfusion with low-potassium dextran for donor isolated lung preservation.
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OBJECTIVE: To test the validity of continuous low-flow perfusion with low-potassium dextran (LPD) to preserve rabbit lung. METHODS: Isolated rabbit lungs were preserved for eight hours either in Ringer's solution by simple storage (Group I) or in continuous low-flow perfusion with LPD (Group II). After preservation, lung functions were assessed to compare these two methods. RESULTS: The water gain in Group I was higher than that in Group II. During reperfusion, the functional test values for the immersed lungs were lower than those for the perfused lungs. The lipid peroxidation product (MDA) was significantly decreased in perfused lungs during reperfusion. CONCLUSIONS: Low-flow perfusion with LPD is better than immersion for the lung preservation. (+info)
Opening of potassium channels: the common cardioprotective link between preconditioning and natural hibernation?
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BACKGROUND: The tolerance of hibernating mammals to cold hypoxia is related to a factor similar to agonists of delta-opioid receptors. This study was designed to assess whether activation of these receptors could reproduce the protection conferred by ischemic preconditioning and whether such cardioprotection was similarly mediated by an opening of ATP-sensitive potassium (KATP) channels. METHODS AND RESULTS: Thirty-two isolated rat hearts were arrested with and stored in Celsior at 4 degrees C for 5 hours before being reperfused for 2 hours. They were divided into 4 equal groups. Group 1 hearts served as controls. In group 2, ischemic preconditioning was elicited by two 5-minute global ischemia periods interspersed with 5 minutes of reperfusion before arrest. In group 3, hearts were pharmacologically preconditioned with a 15-minute infusion of the delta-opioid receptor agonist D-Ala2-D-Leu5-enkephalin (DADLE; 200 micromol/L). In group 4, the protocol was similar to group 3 except that infusion of DADLE was preceded by infusion of the KATP blocker glibenclamide (50 micromol/L). The salutary effects of both forms of preconditioning were primarily manifest as a better preservation of diastolic function, a reduced myocardial edema, and reduced creatine kinase leakage. This protection was abolished by administration of glibenclamide before DADLE. CONCLUSIONS: These data suggest that activation of delta-opioid receptors improves recovery of cold-stored hearts to a similar extent as ischemic preconditioning, most likely through an opening of KATP channels. This provides a rationale for improving the preservation of hearts for transplantation by pharmacologically duplicating the common pathway to natural hibernation and preconditioning. (+info)
Endothelium-dependent relaxation of canine pulmonary artery endothelium after prolonged preservation.
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OBJECTIVE: Experiments were designed to investigate the effect of Euro-Collins (EC) solution and University of Wisconsin (UW) solution on function of pulmonary arterial endothelium. METHODS: Third order canine pulmonary artery segments were preserved in cold (4 degrees C) UW (group 1, n = 8) or EC (group 2, n = 9) solutions for 16 hours. The preserved (group 1 and 2) and control (group 3, n = 7) pulmonary arterial segments with and without endothelium were studied in vitro in organ chambers to measure isometric tension. RESULTS: The endothelium-dependent relaxation to acetylcholine and adenosine diphosphate of group 1 and 3 were significantly better than those of group 2. CONCLUSIONS: We concluded that endothelium-dependent relaxation of canine pulmonary arterial endothelium to receptor-dependent acetylcholine and adenosine diphosphate were impaired after preservation with Euro-Collins solution. However, endothelium-dependent relaxation of pulmonary segments were well maintained after preservation with University of Wisconsin solution. (+info)
Organ preservation solutions increase endothelial permeability and promote loss of junctional proteins.
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OBJECTIVE: To investigate the effects of the organ preservation solutions UW and Plegisol on endothelial permeability; occludin and vascular endothelial (VE)-cadherin content in human umbilical vein endothelial cells (HUVEC); and junctional localization of these proteins after exposure to these solutions. SUMMARY BACKGROUND DATA: Organ preservation for transplantation is limited by several challenges, including loss of tissue function, tissue injury, and tissue edema. Occludin and VE-cadherin are responsible for maintaining and regulating the endothelial solute barrier. Several studies have noted organ edema and dysfunction with preservation, as well as gaps between endothelial cells suggesting that disorganization of junctional proteins (e.g., occludin and VE-cadherin) is responsible for interstitial edema. METHODS: HUVEC monolayers were treated with 4 degrees C UW and Plegisol for 3 and 6 hours and then reperfused with normal buffer. Permeability was examined using FITC-dextran tracer during the reperfusion phase. Occludin and VE-cadherin content at different time points was measured by Western blotting. Treated groups were also examined by immunofluorescence for occludin, VE-cadherin, and F-actin. RESULTS: Compared with untreated controls, cold preservation for 3 and 6 hours increased endothelial permeability after rewarming, which appears to depend on the duration of cold exposure. Monolayers exposed to 3 hours of cold preservation did not have increased permeability in the first hour after rewarming but had significantly increased permeability after the first hour and all subsequent time points. Monolayers exposed to 6 hours of cold preservation had increased permeability after the first hour and at all later time points. Western blotting demonstrated that occludin content was decreased to a similar extent with all solutions after 3 hours of cold preservation. Six hours of cold preservation in Plegisol reduced the occludin content significantly compared with UW and control. VE-cadherin content was unchanged after 3 hours of cold preservation but was dramatically reduced in all groups at 6 hours. Immunofluorescent staining demonstrated junctional gap formation and discontinuous staining of occludin and VE-cadherin with all cold preservation protocols; changes in F-actin organization were observed at 3 and 6 hours after cold preservation. CONCLUSION: The changes in occludin, VE-cadherin, and F-actin content and organization and increased permeability associated with cold storage demonstrate that alterations of the tight and adherens junctions may underlie organ edema associated with cold organ preservation. These data also suggest that novel strategies to maintain the content and integrity of endothelial junctional proteins may provide an important therapeutic avenue for organ preservation. (+info)
Cold preservation of the human colon and ileum with University of Wisconsin solution.
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The inclusion of the colon in the intestinal graft resulted in worsening patient and graft outcome and increased the incidence of infection and rejection. In this study, we examine the role of ischemia on the barrier function of the epithelium during cold ischemia. Samples were collected from 15 harvested and transplanted human donor grafts (colon, 10; ileum, 6), which were immersed in University of Wisconsin (UW) solution. Ischemia (6, 12, 24, and 48 h) and reoxygenation were performed to evaluate the mucosal electrical status using the Ussing chamber technique. The functions of enterocytes and crypt cells were tested by glucose and theophylline challenge. Modified Park's classification was applied to evaluate the severity of mucosal damage under light microscopy. The colon had higher levels of baseline potential difference, short-circuit current, and resistance than the ileum during 6 48 h of ischemia. Colonic epithelial cells responded well to theophylline stimulation at 24 h of ischemia, while there was no ileal response. The colonic mucosa was histopathologically well preserved in UW solution for 48 h, and mucosal damage induced by reoxygenation was less than in the ileum. In conclusion, electrophysiologically and histopathologically, the colon is less susceptible to cold preservation damage than the ileum during storage with UW solution. (+info)
Rapid thawing increases the fragility of the cryopreserved arterial wall.
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OBJECTIVE: To extend present knowledge of the biomechanical and structural changes which occur in the cryopreserved, rapidly thawed arterial wall. MATERIALS AND METHODS: Minipig iliac arterial segments were cryopreserved at -196 degrees C in either minimum essential medium or Wisconsin solution. Fresh segments served as the control group. After 1 month, the specimens were rapidly thawed (37 degrees C) and processed for biomechanical, ultrastructural, morphological and immunohistochemical (MMP-1, MMP-2, MMP-3 and MMP-9) analysis. Visualisation of apoptotic cells was performed by TUNEL method. For the mechanical distension analysis, an in vitro circuit was designed. RESULTS: The cryopreserved segments showed a 42% incidence of spontaneous fracture and the appearance of microfractures which affected the endoluminal third of the vessel. An accumulation of liquid in the subelastica was observed. An increased expression of wall-degradative enzymes (mainly MMP-2) was also observed following cryopreservation. No significant differences were detected in the proportional elasticity module or tensile strength of the specimen groups. No differences in mechanical distension were observed between groups after the vessel segments were subjected to the pulsatile circuit flow for 72 h. Cell damage was most intense in the specimens cryopreserved in Wisconsin solution. CONCLUSIONS: Cryopreservation in both the solutions employed, followed by rapid thawing, induce changes in the permeability which increase the fragility of the cryopreserved arterial wall. Both increased expression of wall-degradative enzymes and accumulation of liquid may contribute to graft failure after implantation. (+info)