Increased Expression of LIGHT/TNFSF14 and its Receptors in Experimental and Clinical Heart Failure

BACKGROUND: Clinical and experimental studies suggest a pathogenic role for inflammation in chronic heart failure (HF). LIGHT is a member of the tumour necrosis factor superfamily involved in innate and adaptive immune responses. AIMS: We sought to investigate a potential pathogenic role of LIGHT in chronic HF. METHODS: We used various clinical and experimental approaches including studies in post-infarction HF rats and in vitro studies of endothelial cells and peripheral blood mononuclear cells (PBMC). RESULTS: Our main findings were: (i) LIGHT and its receptors (i.e., HVEM and lymphotoxin-beta receptor) were regulated during experimental HF, with strong expression in the infarcted area accompanied by up-regulation of HVEM in cardiomyocytes and endothelial cells also in the non-ischaemic part of the left ventricle. (ii) Patients with chronic HF had significantly increased expression of LIGHT on CD3(+) T-cells accompanied by increased expression of HVEM on monocytes and within the failing myocardium. (iii) LIGHT induced interleukin (IL)-6 expression in endothelial cells. In HF patients, but not in healthy controls, such an IL-6-inducing effect was also seen in LIGHT activated PBMC. CONCLUSION: Our findings in both clinical and experimental HF may suggest a role for LIGHT signalling pathways in the progression of chronic HF involving IL-6-related mechanisms.