Immunomodulatory response in an experimental model of brain death.

Liver transplantation has come a long way and is now regarded as the gold standard treatment for end-stage liver failure. The great majority of livers utilized in transplantation come from brain-dead donors. A broad inflammatory response characterizes BD, resulting in multiorgan damage. This process is primarily mediated by cytokines, which increase the immunogenicity of the graft. In male Lewis rats, we evaluated the immune response in a BD liver donor and compared it to that of a control group. We studied two groups: Control and BD (rats subjected to BD by increasing intracranial pressure). After the induction of BD, there was an intense rise in blood pressure followed by a fall. There were no significant differences observed between the groups. Blood tissue and hepatic tissue analyzes showed an increase in plasma concentrations of liver enzymes (AST, ALT, LDH and ALP), in addition to pro-inflammatory cytokines and macrophages in liver tissue in animals submitted to BD. The current study found that BD is a multifaceted process that elicits both a systemic immune response and a local inflammatory response in liver tissue. Our findings strongly suggested that the immunogenicity of plasma and liver increased with time following BD.

Thalidomide modulates renal inflammation induced by brain death experimental model.

BACKGROUND: Brain death (BD) is characterized by a complex inflammatory response, resulting in dysfunction of potentially transplantable organs. This process is modulated by cytokines, which amplify graft immunogenicity. We have investigated the inflammatory response in an animal model of BD and analyzed the effects of thalidomide, a drug with powerful immunomodulatory properties. METHODS: BD was induced in male Lewis rats. We studied three groups: Control (sham-operated rats) (n = 6), BD (rats subjected to brain death) (n = 6) and BD + Thalid (BD rats treated with one dose of thalidomide (200 mg/Kg), administered by gavage) (n = 6). Six hours after BD, serum levels of urea and creatinine, as well as systemic and renal tissue protein levels of TNF-α and IL-6, were analyzed. We also determined the mRNA expression of ET-1, and macrophage infiltration by immunohistochemistry. RESULTS: BD induced a striking inflammatory status, demonstrated by a significant increase of plasma cytokines: TNF-α (2.8 ± 4.3 pg/mL [BD] vs. 9.4 ± 2.8 pg/mL [Control]), and IL-6 (6219.5 ± 1380.6 pg/mL [BD] vs. 1854.7 ± 822.6 pg/mL [Control]), and in the renal tissue: TNF-α (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.4 relative expression [Control]; p < 0.05), and IL-6 (4.0 ± 0.4 relative expression [BD] vs. 1.0 ± 0.3 relative expression [Control]; p < 0.05). Moreover, BD increased macrophages infiltration (2.47 ± 0.07 cells/field [BD] vs. 1.20 ± 0.05 cells/field [Control]; p < 0.05), and ET-1 gene expression (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.2 relative expression [Control]; p < 0.05). In addition, we have observed deterioration in renal function, characterized by an increase of urea (194.7 ± 25.0 mg/dL [BD] vs. 108.0 ± 14.2 mg/dL [Control]; p < 0.05) and creatinine (1.4 ± 0.04 mg/dL [BD] vs. 1.0 ± 0.07 mg/dL [Control]; p < 0.05) levels. Thalidomide administration significantly reduced plasma cytokines: TNF-α (5.1 ± 1.4 pg/mL [BD + Thalid] vs. BD; p < 0.05), and IL-6 (1056.5 ± 488.3 pg/mL [BD + Thalid] vs. BD; p < 0.05), as well as in the renal tissue: TNF-α (1.5 ± 0.2 relative expression [BD + Thalid] vs. BD; p < 0.05), and IL-6 (2.1 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05). Thalidomide treatment also induced a significant decrease in the expression of ET-1 (1.4 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05), and macrophages infiltration (1.17 ± 0.06 cells/field [BD + Thalid] vs. BD; p < 0.05). Also thalidomide prevented kidney function failure by reduced urea (148.3 ± 4.4 mg/dL [BD + Thalid] vs. BD; p < 0.05), and creatinine (1.1 ± 0.14 mg/dL [BD + Thalid] vs. BD; p < 0.05). CONCLUSIONS: The immunomodulatory properties of thalidomide were effective in decreasing systemic and local immunologic response, leading to diminished renal damage, as reflected in the decrease of urea and creatinine levels. These results suggest that use of thalidomide may represent a potential strategy for treating in BD kidney organ donors.

Immunomodulatory effects of thalidomide in an experimental brain death liver donor model.

Brain death is characterized by a generalized inflammatory response that results in multiorgan damage. This process is mainly mediated through cytokines, which amplify graft immunogenicity. We investigated the immunological response in a brain death liver donor model and analysed the effects of thalidomide, a drug with powerful immunomodulatory properties. Brain death was induced in male Lewis rats. We studied three groups: Control (sham-operated rats in which trepanation was performed without inserting the balloon catheter), BD (rats subjected to brain death by increasing intracranial pressure) and BD + Thalid (BD rats receiving thalidomide after brain death). After 6 h, serum levels of AST, ALT, LDH, and ALP as well as systemic and hepatic levels of TNF-α, IL1-ß, IL-6, and IL-10 were analysed. We also determined the mRNA expression of MHC Class I and Class II, NF-κB, and macrophage infiltration. NF-κB was also examined by electrophoretic mobility shift assay. Thalidomide treatment significantly reduced serum levels of hepatic enzymes and TNF-α, IL-1-ß, and IL-6. These cytokines were evaluated at either the mRNA expression or protein level in liver tissue. In addition, thalidomide administration resulted in a significant reduction in macrophages, MHC Class I and Class II, and NF-κB activation. This study reveals that thalidomide significantly inhibited the immunologic response and graft immunogenicity, possibly through suppression of NF-κB activation.