Chronic rejection is the most common cause of graft loss in renal transplantation. The pathomecha... more Chronic rejection is the most common cause of graft loss in renal transplantation. The pathomechanisms underlying chronic rejection are poorly understood, and no treatment has yet successfully been established. We hypothesized that, in analogy to models of reduced renal mass, the administration of a selective endothelin (ET) A receptor antagonist could improve the course of chronic rejection in renal allografts. Experiments were performed in the Fisher-to-Lewis rat model of chronic rejection. Lewis-->Lewis isografts served as controls. Animals were treated with either the oral selective ET-A receptor antagonist LU135252 (50 mg/kg/day) or vehicle. Animal survival, blood pressure, creatinine clearance, proteinuria, and urinary ET excretion were investigated for 24 weeks. Kidneys were removed for light microscopical evaluation, determination of ET mRNA expression and tissue protein concentration, and immunohistochemical assessment of cell surface markers. Rats with chronic rejection showed an increase in renal ET mRNA synthesis and ET protein content. Treatment with LU135252 resulted in a significant improvement in survival after 24 weeks (0.92 vs. 0.38, P<0.01 by log-rank test). Creatinine clearance was higher in animals treated with the selective ET-A receptor antagonist (P<0.05). LU135252 had no influence on blood pressure and proteinuria. Selective ET-A blockade was associated with significantly less morphological changes and a significant reduction of expression of cell surface markers for macrophages (ED1), T cells (R73), and MHC II (F17-23-2). The renal ET-A system plays an important role in the pathomechanisms underlying chronic renal allograft rejection, because the treatment with a selective ET-A receptor antagonist dramatically improves the course of chronic renal failure after allograft transplantation. These results offer a novel therapeutical option for treatment of chronic renal allograft rejection, for which so far no therapy is known.
Transplant international : official journal of the European Society for Organ Transplantation, 2007
The aim of the study was to evaluate the effect of the hypersulfated nonanticoagulant heparin der... more The aim of the study was to evaluate the effect of the hypersulfated nonanticoagulant heparin derivative LU 51198 (LU) and of the low molecular weight heparin reviparin (REVI) on ischemia/reperfusion (I/R) injury, acute rejection (AR) and chronic allograft nephropathy (CAN) in rats. Organs were harvested 5 days after 60 min of renal I/R injury. For investigation of AR and CAN we used the allogeneic Fisher-Lewis model. Kidneys were harvested at one respectively 32 weeks after transplantation. Rats were treated with either vehicle, LU or REVI. After I/R injury, treatment with REVI or LU reduced infiltration with MHC II and R73-positive cells, whereas only REVI reduced ED1-positive cells and expression of monocyte chemoattractant protein-1. There was no effect of REVI and LU on acute allograft rejection. Treatment with LU or REVI reduced glomerular infiltration with ED1 and MHCII-positive cells and renal expression of transforming growth factor-beta 32 weeks after transplantation. Only...
The pathogenesis of calcium oxalate stone formation is not completely understood. Recently, an in... more The pathogenesis of calcium oxalate stone formation is not completely understood. Recently, an influence of vascular phenomena like arteriosclerosis on the crystallization process was hypothesized. Thus, stone formation should be more common in patients with diabetes mellitus (DM) who are at risk of developing angiopathy. The aim of the study was to determine the prevalence of urolithiasis (UL) in patients with DM and to identify specific risk factors. 350 patients with DM were evaluated with respect to DM-related history, and a total of 179 patients was included (83 female, 96 male; age 23-84 years). All patients were interviewed to assess the history of stone formation. These data were compared to epidemiological data in Germany. The overall prevalence of UL in the diabetic group was 7.82% (vs. 4.73% in Germany, p = 0.0485; binominal test). The prevalence was significantly higher in patients with coronary heart disease (25%; p < 0.0001; Fisher's exact test). We could not de...
Journal of the American Society of Nephrology : JASN, 1998
Polycystic kidney disease (PKD) is characterized by interstitial fibrosis and formation of renal ... more Polycystic kidney disease (PKD) is characterized by interstitial fibrosis and formation of renal cysts. Interestingly, interstitial fibrosis and renal cyst formation were also seen in human endothelin-1 (ET-1) transgenic mice. This study, therefore, analyzes the tissue distribution of ET-1, the tissue concentrations of ET-1, as well as the expression of ET receptor subtypes in the kidneys of a rat model of PKD: Han:SPRD rats. Six-week-old heterozygous (cy/+) and homozygous (cy/cy), as well as 6-mo-old heterozygous (cy/+) Han:SPRD rats and the corresponding age-matched Sprague Dawley littermates (SD) (+/+) were analyzed. Furthermore, the acute effects of the mixed (A/B) endothelin receptor antagonist bosentan on hemodynamic and renal function were investigated in 6-mo-old, conscious, chronically instrumented (cy/+) rats. The kidneys of affected rats showed significantly elevated tissue levels of ET-1 compared with age-matched controls (3.5 +/- 0.3-fold in young cy/cy rats, P < 0.0...
Retrospective transplant database analysis revealed that administration of catecholamines to orga... more Retrospective transplant database analysis revealed that administration of catecholamines to organ donors reduces acute rejection episodes and improves graft survival after renal transplantation. In the present study, the authors investigated the influence of dopamine donor pretreatment before prolonged cold storage on short- and long-term graft outcome after allogeneic kidney transplantation. Fisher donor rats were treated intravenously for 24 hr with dopamine or isotonic saline, Lewis rats treated with saline served as controls. Explanted kidneys were stored for 24 hr at 4 degrees C in University of Wisconsin solution and transplanted into Lewis rats. Dopamine pretreatment markedly reduced the infiltration of monocytes down to the level of isogeneic controls 5 days after allogeneic transplantation and hastened recovery of renal function in the first days after transplantation. After 24 weeks, serum creatinine and proteinuria were significantly lower in recipients of dopamine-treated grafts. Histologically, dopamine donor pretreatment significantly reduced the severity of chronic allograft nephropathy. Survival of animals that underwent transplantation was improved by dopamine pretreatment of donors (P=0.04). Pretreatment of organ donors with dopamine improves short- and long-term outcome after prolonged cold storage and subsequent allogeneic kidney transplantation in rats. The authors&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; experimental data demonstrate that donor treatment is a simple and effective approach for preventing long-term graft loss after kidney transplantation.
Brain death has been identified as an independent risk factor for chronic allograft dysfunction. ... more Brain death has been identified as an independent risk factor for chronic allograft dysfunction. In two independent retrospective clinical studies, we showed that dopamine treatment of brain-dead donors improves long-term kidney graft survival. The mechanisms underlying the protective effects of dopamine treatment in vivo have not been identified. To elucidate the mechanisms underlying the protective effect of dopamine on kidneys of brain-dead donors, we studied a model for brain death in rats. In F344 rats, brain death was induced by epidural inflation of a 3F Fogarty catheter. Apneic animals were mechanically ventilated, and clinically relevant dosages of dopamine (2, 6, 10, or 14 microg/kg/min) were given for 6 hr from the onset of brain death. Ventilated, non-brain-dead animals served as controls. Dopamine significantly reduced renal monocyte infiltration and major histocompatibility class II and P-selectin expression in brain-dead animals. It also prevented further up-regulation of the inflammatory markers tumor necrosis factor-alpha and monocyte chemoattractant peptide-1. Concomitantly, the presence of inducible anti-oxidant heme oxygenase-1, known for its cytoprotective effects, was strongly increased by dopamine. We identified several mechanisms underlying the protective effects of dopamine treatment on kidney grafts. The identification of these mechanisms may help to design more effective future strategies for treatment of cadaveric kidney donors.
The aim of the present study was to evaluate the effect of donor pretreatment with atorvastatin o... more The aim of the present study was to evaluate the effect of donor pretreatment with atorvastatin on ischemia/reperfusion (I/R) injury in renal transplantation in rats. Donor rats were pretreated orally with atorvastatin or vehicle 2 days prior to explantation. Kidneys were stored for 24 hr at 4 degrees C in University of Wisconsin solution and transplanted into isogeneic or allogeneic recipients. Donor treatment with atorvastatin improved initial graft function, reduced renal inflammation, and the number of TUNEL-positive cells in renal tissue after prolonged cold storage and isogeneic transplantation. In the allogeneic transplantation model, donor treatment with atorvastatin reduced renal inflammation in grafts harvested after 5 days, but no improvement of long-term graft survival (24 weeks) could be observed. A genome wide gene expression profile of donor kidneys from atorvastatin treated or vehicle treated rats revealed a fivefold downregulation of aldose reductase in all atorvastatin treated animals (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Donor treatment with an aldose-reductase inhibitor improved kidney function and reduced renal inflammation after prolonged cold storage and isogeneic transplantation. Our data suggest that downregulation of aldose reductase in renal tissue might underlie the protective effect of donor atorvastatin treatment. Donor pretreatment with a statin or an aldose reductase inhibitor could offer a new treatment strategy to prevent transplantation associated tissue injury.
Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts ... more Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts independently from immunosuppressive treatment. Furthermore, long-term treatment reduces the development of chronic graft vascular disease after experimental heart transplantation. The aim of the present study was to determine whether treatment with the LMWH reviparin has a beneficial effect on chronic rejection in a rat renal allograft model. Kidneys of Fisher (F344) rats were transplanted into unilaterally nephrectomized Lewis (LEW) recipients. LEW--&gt;LEW isografts served as controls. Animals were treated with cyclosporine (5 mg/kg/d) for the first 10 days. Nephrectomy of the remaining kidney was performed after 10 days. Allografted animals were treated either with reviparin (2 mg/kg/d subcutaneously) for 24 weeks (Allo-24), from week 12 to 24 (Allo-12), or with vehicle for 24 weeks. Proteinuria was determined at regular intervals. Kidneys were harvested after 24 weeks for histomorphological and immunohistochemical evaluation. No major bleeding complications were observed in reviparin-treated animals. Proteinuria was significantly reduced in allografted animals both by early as well as by late-onset treatment with reviparin. Transplant glomerulopathy was diminished in Allo-24 and in Allo-12 groups compared to vehicle-treated animals, whereas tubulointerstitial inflammation was influenced only in animals immediately treated with reviparin. Immunohistochemical studies demonstrated a marked reduction of renal monocyte and T-cell infiltration as well as expression of MHC II by treatment with reviparin. Treatment with the LMWH reviparin significantly improved chronic renal allograft rejection in the F344-to-LEW rat model, both after early and late start of therapy. Although the exact mechanisms of this beneficial effect remain unclear, our data offer a potential new therapeutical approach for prevention of chronic allograft nephropathy.
Donor dopamine usage is associated with improved immediate graft function after renal transplanta... more Donor dopamine usage is associated with improved immediate graft function after renal transplantation. Although prolonged cold preservation results in an increased vascular permeability, the present study was conducted to examine in vitro and in vivo if dopamine pretreatment influences endothelial barrier function under such conditions. To assess cold preservation injury in vitro and in vivo, cultured human umbilical vein endothelial cells (HUVEC) and Lewis donor rats were pretreated with dopamine or isotonic saline prior to cold storage. Injury was determined by lactate dehydrogenase (LDH) release, histology, and functional analysis. In vitro cold storage resulted in intercellular gap formation in both untreated and dopamine pretreated HUVEC. In the latter monolayer integrity was completely restored upon rewarming and paracellular transport of fluorescein isothiocyanate-dextran was significantly reduced. In dopamine treated HUVEC, intercellular gap formation was independent of cell death and was associated with redistribution of junctional proteins and condensation of cytoskeleton proteins. In untreated HUVEC proteolysis and cell death were clearly evident after hypothermia. Closing of intercellular gaps was dependent on p42/p44 activation. Regeneration of adenosine triphosphate was only observed in dopamine pretreated cells. Only in dopamine treated Lewis renal allografts subjected to cold storage, activation of p42/p44 occurred upon rewarming. These grafts had a better renal function and displayed less inflammatory cells five days after transplantation. Our study demonstrates beneficial effects of dopamine treatment on cold storage induced endothelial barrier disturbances. This may contribute to the positive effects of catecholamines on immediate graft function of renal allografts in men.
Chronic rejection is the most common cause of graft loss in renal transplantation. The pathomecha... more Chronic rejection is the most common cause of graft loss in renal transplantation. The pathomechanisms underlying chronic rejection are poorly understood, and no treatment has yet successfully been established. We hypothesized that, in analogy to models of reduced renal mass, the administration of a selective endothelin (ET) A receptor antagonist could improve the course of chronic rejection in renal allografts. Experiments were performed in the Fisher-to-Lewis rat model of chronic rejection. Lewis--&gt;Lewis isografts served as controls. Animals were treated with either the oral selective ET-A receptor antagonist LU135252 (50 mg/kg/day) or vehicle. Animal survival, blood pressure, creatinine clearance, proteinuria, and urinary ET excretion were investigated for 24 weeks. Kidneys were removed for light microscopical evaluation, determination of ET mRNA expression and tissue protein concentration, and immunohistochemical assessment of cell surface markers. Rats with chronic rejection showed an increase in renal ET mRNA synthesis and ET protein content. Treatment with LU135252 resulted in a significant improvement in survival after 24 weeks (0.92 vs. 0.38, P&lt;0.01 by log-rank test). Creatinine clearance was higher in animals treated with the selective ET-A receptor antagonist (P&lt;0.05). LU135252 had no influence on blood pressure and proteinuria. Selective ET-A blockade was associated with significantly less morphological changes and a significant reduction of expression of cell surface markers for macrophages (ED1), T cells (R73), and MHC II (F17-23-2). The renal ET-A system plays an important role in the pathomechanisms underlying chronic renal allograft rejection, because the treatment with a selective ET-A receptor antagonist dramatically improves the course of chronic renal failure after allograft transplantation. These results offer a novel therapeutical option for treatment of chronic renal allograft rejection, for which so far no therapy is known.
Transplant international : official journal of the European Society for Organ Transplantation, 2007
The aim of the study was to evaluate the effect of the hypersulfated nonanticoagulant heparin der... more The aim of the study was to evaluate the effect of the hypersulfated nonanticoagulant heparin derivative LU 51198 (LU) and of the low molecular weight heparin reviparin (REVI) on ischemia/reperfusion (I/R) injury, acute rejection (AR) and chronic allograft nephropathy (CAN) in rats. Organs were harvested 5 days after 60 min of renal I/R injury. For investigation of AR and CAN we used the allogeneic Fisher-Lewis model. Kidneys were harvested at one respectively 32 weeks after transplantation. Rats were treated with either vehicle, LU or REVI. After I/R injury, treatment with REVI or LU reduced infiltration with MHC II and R73-positive cells, whereas only REVI reduced ED1-positive cells and expression of monocyte chemoattractant protein-1. There was no effect of REVI and LU on acute allograft rejection. Treatment with LU or REVI reduced glomerular infiltration with ED1 and MHCII-positive cells and renal expression of transforming growth factor-beta 32 weeks after transplantation. Only...
The pathogenesis of calcium oxalate stone formation is not completely understood. Recently, an in... more The pathogenesis of calcium oxalate stone formation is not completely understood. Recently, an influence of vascular phenomena like arteriosclerosis on the crystallization process was hypothesized. Thus, stone formation should be more common in patients with diabetes mellitus (DM) who are at risk of developing angiopathy. The aim of the study was to determine the prevalence of urolithiasis (UL) in patients with DM and to identify specific risk factors. 350 patients with DM were evaluated with respect to DM-related history, and a total of 179 patients was included (83 female, 96 male; age 23-84 years). All patients were interviewed to assess the history of stone formation. These data were compared to epidemiological data in Germany. The overall prevalence of UL in the diabetic group was 7.82% (vs. 4.73% in Germany, p = 0.0485; binominal test). The prevalence was significantly higher in patients with coronary heart disease (25%; p < 0.0001; Fisher's exact test). We could not de...
Journal of the American Society of Nephrology : JASN, 1998
Polycystic kidney disease (PKD) is characterized by interstitial fibrosis and formation of renal ... more Polycystic kidney disease (PKD) is characterized by interstitial fibrosis and formation of renal cysts. Interestingly, interstitial fibrosis and renal cyst formation were also seen in human endothelin-1 (ET-1) transgenic mice. This study, therefore, analyzes the tissue distribution of ET-1, the tissue concentrations of ET-1, as well as the expression of ET receptor subtypes in the kidneys of a rat model of PKD: Han:SPRD rats. Six-week-old heterozygous (cy/+) and homozygous (cy/cy), as well as 6-mo-old heterozygous (cy/+) Han:SPRD rats and the corresponding age-matched Sprague Dawley littermates (SD) (+/+) were analyzed. Furthermore, the acute effects of the mixed (A/B) endothelin receptor antagonist bosentan on hemodynamic and renal function were investigated in 6-mo-old, conscious, chronically instrumented (cy/+) rats. The kidneys of affected rats showed significantly elevated tissue levels of ET-1 compared with age-matched controls (3.5 +/- 0.3-fold in young cy/cy rats, P < 0.0...
Retrospective transplant database analysis revealed that administration of catecholamines to orga... more Retrospective transplant database analysis revealed that administration of catecholamines to organ donors reduces acute rejection episodes and improves graft survival after renal transplantation. In the present study, the authors investigated the influence of dopamine donor pretreatment before prolonged cold storage on short- and long-term graft outcome after allogeneic kidney transplantation. Fisher donor rats were treated intravenously for 24 hr with dopamine or isotonic saline, Lewis rats treated with saline served as controls. Explanted kidneys were stored for 24 hr at 4 degrees C in University of Wisconsin solution and transplanted into Lewis rats. Dopamine pretreatment markedly reduced the infiltration of monocytes down to the level of isogeneic controls 5 days after allogeneic transplantation and hastened recovery of renal function in the first days after transplantation. After 24 weeks, serum creatinine and proteinuria were significantly lower in recipients of dopamine-treated grafts. Histologically, dopamine donor pretreatment significantly reduced the severity of chronic allograft nephropathy. Survival of animals that underwent transplantation was improved by dopamine pretreatment of donors (P=0.04). Pretreatment of organ donors with dopamine improves short- and long-term outcome after prolonged cold storage and subsequent allogeneic kidney transplantation in rats. The authors&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; experimental data demonstrate that donor treatment is a simple and effective approach for preventing long-term graft loss after kidney transplantation.
Brain death has been identified as an independent risk factor for chronic allograft dysfunction. ... more Brain death has been identified as an independent risk factor for chronic allograft dysfunction. In two independent retrospective clinical studies, we showed that dopamine treatment of brain-dead donors improves long-term kidney graft survival. The mechanisms underlying the protective effects of dopamine treatment in vivo have not been identified. To elucidate the mechanisms underlying the protective effect of dopamine on kidneys of brain-dead donors, we studied a model for brain death in rats. In F344 rats, brain death was induced by epidural inflation of a 3F Fogarty catheter. Apneic animals were mechanically ventilated, and clinically relevant dosages of dopamine (2, 6, 10, or 14 microg/kg/min) were given for 6 hr from the onset of brain death. Ventilated, non-brain-dead animals served as controls. Dopamine significantly reduced renal monocyte infiltration and major histocompatibility class II and P-selectin expression in brain-dead animals. It also prevented further up-regulation of the inflammatory markers tumor necrosis factor-alpha and monocyte chemoattractant peptide-1. Concomitantly, the presence of inducible anti-oxidant heme oxygenase-1, known for its cytoprotective effects, was strongly increased by dopamine. We identified several mechanisms underlying the protective effects of dopamine treatment on kidney grafts. The identification of these mechanisms may help to design more effective future strategies for treatment of cadaveric kidney donors.
The aim of the present study was to evaluate the effect of donor pretreatment with atorvastatin o... more The aim of the present study was to evaluate the effect of donor pretreatment with atorvastatin on ischemia/reperfusion (I/R) injury in renal transplantation in rats. Donor rats were pretreated orally with atorvastatin or vehicle 2 days prior to explantation. Kidneys were stored for 24 hr at 4 degrees C in University of Wisconsin solution and transplanted into isogeneic or allogeneic recipients. Donor treatment with atorvastatin improved initial graft function, reduced renal inflammation, and the number of TUNEL-positive cells in renal tissue after prolonged cold storage and isogeneic transplantation. In the allogeneic transplantation model, donor treatment with atorvastatin reduced renal inflammation in grafts harvested after 5 days, but no improvement of long-term graft survival (24 weeks) could be observed. A genome wide gene expression profile of donor kidneys from atorvastatin treated or vehicle treated rats revealed a fivefold downregulation of aldose reductase in all atorvastatin treated animals (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Donor treatment with an aldose-reductase inhibitor improved kidney function and reduced renal inflammation after prolonged cold storage and isogeneic transplantation. Our data suggest that downregulation of aldose reductase in renal tissue might underlie the protective effect of donor atorvastatin treatment. Donor pretreatment with a statin or an aldose reductase inhibitor could offer a new treatment strategy to prevent transplantation associated tissue injury.
Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts ... more Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts independently from immunosuppressive treatment. Furthermore, long-term treatment reduces the development of chronic graft vascular disease after experimental heart transplantation. The aim of the present study was to determine whether treatment with the LMWH reviparin has a beneficial effect on chronic rejection in a rat renal allograft model. Kidneys of Fisher (F344) rats were transplanted into unilaterally nephrectomized Lewis (LEW) recipients. LEW--&gt;LEW isografts served as controls. Animals were treated with cyclosporine (5 mg/kg/d) for the first 10 days. Nephrectomy of the remaining kidney was performed after 10 days. Allografted animals were treated either with reviparin (2 mg/kg/d subcutaneously) for 24 weeks (Allo-24), from week 12 to 24 (Allo-12), or with vehicle for 24 weeks. Proteinuria was determined at regular intervals. Kidneys were harvested after 24 weeks for histomorphological and immunohistochemical evaluation. No major bleeding complications were observed in reviparin-treated animals. Proteinuria was significantly reduced in allografted animals both by early as well as by late-onset treatment with reviparin. Transplant glomerulopathy was diminished in Allo-24 and in Allo-12 groups compared to vehicle-treated animals, whereas tubulointerstitial inflammation was influenced only in animals immediately treated with reviparin. Immunohistochemical studies demonstrated a marked reduction of renal monocyte and T-cell infiltration as well as expression of MHC II by treatment with reviparin. Treatment with the LMWH reviparin significantly improved chronic renal allograft rejection in the F344-to-LEW rat model, both after early and late start of therapy. Although the exact mechanisms of this beneficial effect remain unclear, our data offer a potential new therapeutical approach for prevention of chronic allograft nephropathy.
Donor dopamine usage is associated with improved immediate graft function after renal transplanta... more Donor dopamine usage is associated with improved immediate graft function after renal transplantation. Although prolonged cold preservation results in an increased vascular permeability, the present study was conducted to examine in vitro and in vivo if dopamine pretreatment influences endothelial barrier function under such conditions. To assess cold preservation injury in vitro and in vivo, cultured human umbilical vein endothelial cells (HUVEC) and Lewis donor rats were pretreated with dopamine or isotonic saline prior to cold storage. Injury was determined by lactate dehydrogenase (LDH) release, histology, and functional analysis. In vitro cold storage resulted in intercellular gap formation in both untreated and dopamine pretreated HUVEC. In the latter monolayer integrity was completely restored upon rewarming and paracellular transport of fluorescein isothiocyanate-dextran was significantly reduced. In dopamine treated HUVEC, intercellular gap formation was independent of cell death and was associated with redistribution of junctional proteins and condensation of cytoskeleton proteins. In untreated HUVEC proteolysis and cell death were clearly evident after hypothermia. Closing of intercellular gaps was dependent on p42/p44 activation. Regeneration of adenosine triphosphate was only observed in dopamine pretreated cells. Only in dopamine treated Lewis renal allografts subjected to cold storage, activation of p42/p44 occurred upon rewarming. These grafts had a better renal function and displayed less inflammatory cells five days after transplantation. Our study demonstrates beneficial effects of dopamine treatment on cold storage induced endothelial barrier disturbances. This may contribute to the positive effects of catecholamines on immediate graft function of renal allografts in men.
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Papers by Claude Braun