Expression of intercellular adhesion molecule-1 in the cortex of preserved rat kidneys

Donor Dopamine Pretreatment Inhibits Tubulitis in Renal Allografts Subjected to Prolonged Cold Preservation

BACKGROUND

In the present study, we used the Brown-Norway (BN) to Lewis model as a model for acute rejection, to test the hypothesis that dopamine (DA) treatment of BN donors significantly reduces the inflammatory response after renal transplantation.

METHODS

BN and Lewis rats (isograft controls) were treated for 24 hr with DA (5 microg/kg/min) or NaCl (0.9%), respectively. After 24 hr of cold storage in University of Wisconsin (UW) solution, renal allografts were orthotopically transplanted into Lewis recipients. All recipients received immunosuppression until they were sacrificed. Allografts were harvested one, three, five, and 10 days after transplantation and analyzed by light microscopy, immunohistochemistry (CD3, major histocompatibility complex [MHC] class II, ED1, P-selectin and intercellular adhesion molecule [ICAM]-1) and by RNase protection assay for cytokine mRNA.

RESULTS

Ten days after transplantation Banff tubulitis scores were significantly lower in DA-treated than in NaCl-treated allografts. No significant differences were found in Banff interstitial infiltration scores. The numbers of MHC class II+ and CD3+ cells were significantly decreased in DA-treated animals as assessed by immunohistochemistry. No differences were found in the number of ED1+, P-selectin+, and ICAM-1+ cells. The expression of Ltalpha, tumor necrosis factor, interleukin-1beta, and interleukin-2 mRNA was significantly reduced in DA-treated animals.

CONCLUSION

Our data indicate that donor DA treatment significantly inhibits tubulitis in renal allografts subjected to prolonged cold preservation. A reduced number of infiltrating MHC class II+ and CD3+ cells together with decreased cytokine expression could diminish renal scarring, reduce allograft immunogenicity, and hence improve transplantation outcome.

Influence of Donor Pretreatment with Dopamine on Allogeneic Kidney Transplantation after Prolonged Cold Storage in Rats

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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' experimental data demonstrate that donor treatment is a simple and effective approach for preventing long-term graft loss after kidney transplantation.

Mild hyperhomocysteinemia induced by feeding rats diets rich in methionine or deficient in folate promotes early atherosclerotic inflammatory processes

High homocysteine levels in vitro promote the expression of inflammatory agents responsible for atherogenesis. We investigated the long-term effects of elevated plasma homocysteine on the expression of inflammatory molecules and attempted to elucidate their mechanisms. Male Sprague-Dawley rats (n = 36) were randomly divided into 3 groups, which received the control AIN-93G diet, the control diet plus 10 g/kg of L-methionine, or that diet without folate (0 m/kg) for 14 wk. Mild hyperhomocysteinemia was then induced in both experimental groups. The mildly hyperhomocysteinemic rats had markedly increased expression of intracellular adhesion molecule-1 (ICAM-1) in the aorta and elevated serum levels of monocyte chemoattractant protein-1 (MCP-1), compared to the control rats. The activation of nuclear factor kappaB and formation of nitrotyrosine in the aorta were greater in rats with mild hyperhomocysteinemia than in control rats. Serum levels of malonyldialdehyde (MDA) were higher in mildly hyperhomocysteinemic rats than in control rats. These results suggest that the oxidative stress resulting from elevated plasma homocysteine stimulates the activation of nuclear factor kappaB, and consequently increases the expression of the inflammatory factors in vivo. Such an effect may contribute to atherogenesis by enhancing the inflammatory response of the vascular endothelium.

Oxygenated machine perfusion mitigates surface antigen expression and improves preservation of predamaged donor livers

The aim of the present study was to evaluate the potential benefit of machine preservation with the Belzer MPS or HTK solution, compared to standard cold storage, after procurement of marginal livers from non-heart beating donors in an experimental pilot study. Livers from male Wistar rats (250-300 g bw) were harvested after 60 min of cardiac arrest, flushed via the portal vein and cold stored submerged in HTK for 24 h at 4 degrees C while other organs were subjected to oxygenated machine perfusion with HTK or Belzer's MPS at 5 ml/min at 4 degrees C. Cold perfusion of livers with the non-colloidal HTK was not compromised by the lack of oncotic agents and there was no rise in vascular resistance during the 24 h of machine preservation with HTK or the colloidal Belzer MPS. Viability of the livers was assessed after the cold preservation period by warm reperfusion in vitro. Oxygenated machine perfusion was found to significantly increase viability of the livers vs simple cold storage with respect to portal vascular resistance upon reperfusion, enzyme release as well as functional recovery of oxygen utilization or bile production. Moreover, tissue antigen expression of ICAM-1 or histocompatibility antigen class II could be markedly reduced by oxygenated perfusion preservation as compared to cold storage. It is concluded that predamaged organs should preferably be preserved by oxygenated machine perfusion thus minimizing functional alterations and immunogenicity of the graft. In this setup HTK appeared equally effective as Belzer's MPS for machine preservation.

Gene expression profiling of prolonged cold ischemia and reperfusion in murine heart transplants

BACKGROUND

Heart transplantation causes complex changes in the biological homeostasis of the graft. Current knowledge is restricted to a few genes and regulation of certain factors involved in ischemia-reperfusion (I/R) injury. Efficient strategies to prevent I/R injury, however, require a better understanding of its mechanisms. Using cDNA microarrays, we investigated gene expression profiles of murine cardiac isografts.

METHODS

For microarray hybridization experiments, chips with 8,734 individual target sequences were used. Messenger RNA was extracted from hearts subjected to warm ischemia and different time periods of reperfusion or to prolonged cold ischemia or warm ischemia and transplantation. Native hearts served as controls.

RESULTS

A set of 68 sequences was regulated in all hearts. In addition, grafts without cold ischemia showed differential expression of 65 sequences, which were not found in hearts transplanted after cold storage, and which in turn had 38 sequences regulated and not detected in grafts without cold ischemia. Overall, approximately 50% of regulated transcripts are expressed sequence tags (ESTs) with unknown function. Annotated genes encoded immune modulators (20% of sequences), receptor proteins, structural proteins, and proteins involved in metabolism.

CONCLUSION

Our data demonstrate expression profiles of hearts subjected to prolonged cold ischemia or transplantation in an isogeneic setting. We have defined functional complexes and detected a substantial amount of ESTs encoding novel proteins. These studies may provide a molecular basis for further functional experiments and may help identify potential targets for modulation of postischemic inflammation.