heart failure Tumor necrosis factor-alpha as trigger of platelet activation in patients with

ABSTRACT Clinical history of patients with Heart Failure (HF) is complicated by arterial thromboembolism. Platelet activation was reported in this setting, but the underlying mechanism has not been clarified. 42 patients with HF scored according to NYHA classification had higher collagen-induced platelet aggregation, platelet tumor necrosis factor-alpha (TNF-α) receptor expression, serum thromboxane B 2 and circulating levels of TNF-α than 20 healthy subjects. Coincubation of platelets from HF patients with an inhibitor of TNF-α receptors significantly reduced collagen induced platelet aggregation. In vitro study demonstrated that TNF-α amplified the platelet response to collagen; this effect was inhibited by (a) TNF-α receptor antagonist and (b) inhibitors of arachidonic acid metabolism. This study shows that TNF-α behaves as a trigger of platelet activation via stimulation of the arachidonic acid pathway. Key Words: platelet, TNF- α , Heart Failure, Arachidonic Acid Pathway From bloodjournal.hematologylibrary.org by guest on June 6, 2013. For personal use only.