Endothelin-1 and Human Platelets

There is conflicting evidence regarding the effect of endothelin-1 (ET-1) on platelets. Some studies show that ET-1 activates platelets, others show platelet inhibition with ET-1 and some studies did not detect an effect of ET-1. These conflicting results may be due to complex interactions between platelet ETA and ETB receptors. ET-1 antagonism may emerge as an important therapeutic strategy in the management of several vascular disorders. However, to date the only prescribed ET-1 antagonist is bosentan for pulmonary arterial hypertension. Bosentan is a 'dual' ET- 1 antagonist (i.e. it acts on both ETA and ETB receptors). Whether this action involves an effect on platelets remains to be established. In this review some of the studies describing the effect of ET-1 on human platelets are discussed. Vascular diseases where ET-1 is implicated are also considered.