Tumour necrosis factor is expressed in cardiac tissues of patients with heart failure

Tumour necrosis factor (TNF), a cytokine produced mainly by macrophages, has also been found in vascular smooth muscle cells. Elevated serum levels of TNF have been reported in various cardiac diseases, especially congestive heart failure (CHF). Although the myocardium produces several cytokines, the expression of TNF in human cardiac tissue has not yet been demonstrated. We examined TNF expression in right atrial (RA) specimens obtained from 15 patients during cardiac surgery with immunohistochemistry using an anti-human TNF monoclonal antibody, enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). TNF immunoreactivity was found only in cardiac myocytes and some vascular smooth muscle cells of small vessels of specimens from patients with severe CHF (3/5), and not in those from patients without severe CHF (0/10). ELISA of four RA specimens revealed that RA tissues from two patients with severe CHF contained more TNF than did those from two patients without severe CHF (3.1 and 4.7 pg/mg vs. 0.1 and 0.3 pg/mg). RT-PCR revealed TNF mRNA in all seven cases we examined. It was concluded that TNF mRNA is expressed by atrial tissue. The production of immunoreactive TNF-like peptides by myocytes and vascular smooth muscle cells is augmented in patients with severe CHF.