Aspirin cures erythromelalgia and cerebrovascular disturbances in JAK2-thrombocythemia through platelet-cycloxygenase inhibition

Figure 13 A schematic representation of platelet adhesion through von Willebrand factor and glycoprotein Ib disturbances in Bernard Soulier syndrome, von Willebrand disease and aggregation disturbances in Glanzmann’s thrombasthenia, and receptor defects of ADP (P2PY12, P2Y1), thrombin, thromboxane, platelet activating factor (PAF and collagen induced intracellular metabolites). Source: Rao et al. Inherited defects in platelet signaling. Sem Thromb Hemostas 2004; 30: 525-535. Shear induced platelet activation of JAK2 hypersensitive (sticky) platelets (blue arrow) in arterioles starts with liberation of arachidonic acid from platelet membrane phopholipids by phopholipase A2 (PLA2) and metabolization of arachidonic acid by cyclooxygenase (CO) into prostaglandin endoperoxides PGG2/PGH2 and subsequent thromboxane A2 (TxA2) generation by thromboxane synthetase (TS). Spontaneous activation and aggregation of JAK2 sticky platelets (arrow) occur in the arteriolar peripheral and cerebral endarterial circulation with the production of large amount of prostaglandin endoperoxides as the cause of aspirin responsive inflammatory component of erythromelalgia followed by fibromuscular intimal proliferation and occlusion platelet thrombi in arterioles (Figures 9 and 10). Aspirin cures erythromelalgia in JAK2 thrombocythemia by irreversible inhibition of platelet cycolooxygenase (CO)[37]. In this process the activation of platelets by ADP (P2Y12), thrombin and collagen receptors are not involved in the etiology of erythromelalgia and cerebral vascular disturbances[52,53,79,80]. vWF: Von Willebrand factor; BSS: Bernard Soulier syndrome; vWD: Von Willebrand disease; Ca: Calcium; MLC: Myosin light chain; IP3: Inositoltriphosphate; PLC: Phospholipase C; PIP2: Phosphatidylinositol biphosphate; DG: Diacylglycerl; AC: Adenylcyclase; PKC: Protein kinase C.