Sustained activation of nuclear factor kappa B and activator protein 1 in chronic heart failure

Innate immune response proteins such as inflammatory cytokines, inducible nitric oxide synthase, and toll like receptors are implicated in myocardial depression and left ventricular (LV) remodeling after myocardial infarction (MI). Although all these innate immunity proteins share the downstream activation of the transcription factor NF-kappaB (nuclear factor kappa B) and activator protein 1 (AP-1), the involvement of NF-kappaB and AP-1 in LV remodeling has not been demonstrated so far. Nuclear translocation of NF-kappaB and AP-1 was studied by electrophoretic mobility shift assays and ELISA 10 weeks after large experimental MI in rats, the chronic phase of LV remodeling. In the non-infarcted myocardium of MI rats, NF-kappaB and AP-1 were significantly activated (2.5-fold) as compared to sham-operated animals. Immunohistochemistry demonstrated NF-kappaB activation mainly in cardiac myocytes. Treatment with the ACE (angiotensin converting enzyme) inhibitor trandolapril led to a further 2-fold increase in the activation of NF-kappaB and AP-1 when compared to placebo-treated animals with the same MI size (P