Myocardial nuclear factor-κB activity and nitric oxide production in rejecting cardiac allografts

Matthew Cooper, Paul Lindholm, Galen Pieper, Ross Seibel, Gail Moore, Akemi Nakanishi, Kenneth Dembny, Richard Komorowski, Christopher Johnson, Mark Adams, Allan M. Roza

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62 Scopus citations

Abstract

Background. Nuclear factor-κB (NF-κB) is a rapid response transcription factor for genes whose products are critical for inflammation and immunity. In a rat model of heterotopic cardiac transplantation, we studied NF-κB DNA binding activity and nitric oxide (·NO) production in untreated allografts and whether inhibition of NF-κB suppresses ·NO production and prolongs graft survival. Methods. In allograft recipients and isograft controls, NF-κB was assayed by electrophoretic mobility shift assay, daily from transplant until rejection. Myocardial ·NO was directly detected in explanted allografts by electron spin resonance spectroscopy on day 6 after transplant. The potent inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC; 250 mg/kg s.c.) was administered daily from transplant until day of rejection. The extent of graft lymphocytic infiltrate was assessed by routine hematoxylin and eosin staining. Immunohistochemical staining of NF-κB was per formed to identify the cell type responsible for NF-κB activity. Results. A time-dependent increase in myocardial NF-κB activity was seen in untreated allografts as compared with isografts as determined by PhosphorImage analysis. Peak NF-κB activity occurred in allografts on day 4 with a ninefold increase as compared with isografts (24.0±3.7% vs. 2.7±0.5; P < 0.05). On posttransplant day 6, electron spin resonance spectroscopy analysis of allografts demonstrated ·NO identified by a triplet nitrogen signal centered at g=2.012 with hyperfine splitting of 17.5 Gauss, which is consistent with nitrosoheme formation and low-field signals at g=2.08 and g=2.03 consistent with nitrosomyoglobin. These signals were not seen in native hearts of allograft recipients. With PDTC administration, a threefold decrease in NF-κB activity within the transplanted heart was observed on posttransplant day 5 as compared with untreated allografts (9.7±1.6% vs. 23.5±2.5%; P < 0.01). PDTC prolonged graft survival as compared with untreated allografts (11.7±0.3 vs. 6.6±0.2 days; P < 0.05) and reduced the intensity of the nitrosoheme and nitrosomyoglobin signals. Allograft mononuclear cell infiltrate correlated with peak NF-κB activity with peak infiltrate on posttransplant day 4. PDTC treatment had no effect on the extent of infiltrate. Immunohistochemical staining localized NF-κB to the infiltrating mononuclear cells on posttransplant day 5. Conclusion. These data support a role for NF-κB in allograft rejection.

Original languageEnglish (US)
Pages (from-to)838-844
Number of pages7
JournalTransplantation
Volume66
Issue number7
DOIs
StatePublished - Oct 15 1998

ASJC Scopus subject areas

  • Transplantation

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