Synergistic mechanisms by which sirolimus and cyclosporin inhibit rat heart and kidney allograft rejection Journal Article


Authors: Stepkowski, S. M.; Tian, L.; Napoli, K. L.; Ghobrial, R.; Wang, M. E.; Chou, T. C.; Kahan, B. D.
Article Title: Synergistic mechanisms by which sirolimus and cyclosporin inhibit rat heart and kidney allograft rejection
Abstract: The studies presented herein examined the mechanism(s) whereby sirolimus (SRL) and cyclosporin (CsA) act synergistically to block allograft rejection. Combination index (CI = 1 reflects additive, CI > 1 antagonistic, and CI < 1 synergistic, effects) analysis documented potent synergism between SRL and CsA to block allograft rejection. Combinations of the two drugs produced synergistic prolongation of heart (CI = 0.001-0.2) or kidney (CI = 0.03-0.5) allograft survival at SRL/CsA ratios ranging from 1:12.5 to 1:200. Pharmacokinetic analysis of the individual drugs showed that CsA does not affect the blood levels of SRL, and SRL mildly increases the levels of CsA in SRL/CsA-treated rats. Quantitative polymerase chain reaction analysis was used to document that both subtherapeutic (1.0 mg/kg) and therapeutic (2.0 or 4.0 mg/kg) CsA doses inhibited the expression of interferon-gamma (IFN-γ) (P < 0.03) and IL-2 (P < 0.003) mRNA produced by T helper (Th) 1 cells, as well as IL-10 (P < 0.001), but not IL-4 (NS) mRNA produced by Th2 cells. Contrariwise, all tested SRL doses (0.02, 0.04 or 0.08 mg/kg) did not affect cytokine mRNA expression. However, heart allografts from rat recipients treated with synergistic SRL/CsA doses displayed reduced levels of IFN-γ (P < 0.01), IL-2 (P < 0.001) and IL-10 (P < 0.001) mRNA. Thus, because subtherapeutic doses of CsA reduce Th1/Th2 activity, thereby facilitating the inhibition of signal transduction by low does of SRL, the two agents act synergistically to inhibit allograft rejection.
Keywords: signal transduction; controlled study; transplantation, homologous; nonhuman; animals; interleukin 2; interleukin 10; animal experiment; animal model; drug synergism; cytokines; gamma interferon; messenger rna; rna, messenger; rat; rats; graft rejection; rapamycin; sirolimus; cyclosporin; cyclosporine; immunosuppressive agents; intravenous drug administration; immunosuppression; kidney transplantation; heart transplantation; synergism; male; priority journal; article; rats, inbred buf; polyenes; rats, inbred bn; rats, inbred wf
Journal Title: Clinical and Experimental Immunology
Volume: 108
Issue: 1
ISSN: 0009-9104
Publisher: British Society for Immunology  
Date Published: 1997-04-01
Start Page: 63
End Page: 68
Language: English
PUBMED: 9097913
PROVIDER: scopus
PMCID: PMC1904622
DOI: 10.1046/j.1365-2249.1997.d01-984.x
DOI/URL:
Notes: Article -- Export Date: 17 March 2017 -- Source: Scopus
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MSK Authors
  1. Ting-Chao Chou
    273 Chou