Vascular Endothelial Dysfunction in Myeloproliferative Neoplasms and Gene Mutations A Possible Cause of Coronary Artery Spasm

Essential thrombocythemia (ET) and polycythemia vera (PV), are common Philadelphia-negative myeloproliferative neoplasms (MPN). Patients with MPN have a high rate of cardiovascular complications and often have acquired JAK2V617F and CALR genetic mutations. In this study, we aimed to analyze vascular endothelial function in patients with MPN. We evaluated 27 outpatients, including 10 patients diagnosed with MPN, flow-mediated dilatation (FMD), and nitroglycerin-mediated dilation (NMD), between September 2014 and August 2016. We measured serum adiponectin, which protects vascular endothelial function, and serum asymmetric dimethyl arginine (ADMA), which inhibits the production of adiponectin. The presence or absence of JAK2V617F and CALR mutations was evaluated in patients with MPN. Venous thrombosis was observed more frequently in patients with MPN than in those without. Seven MPN patients were diagnosed with PV, and 3 MPN patients were diagnosed with ET. JAK2V617F and CALR mutations were found in 5 and 3 MPN patients, respectively. FMD was significantly lower in JAK2V617F-positive MPN patients than in JAK2V617F-negative MPN patients, although NMD, adiponectin, and ADMA were similar in both groups. Adiponectin levels were higher and ADMA levels were lower in CALR-positive MPN patients than in CALR-negative MPN patients. There was no difference in FMD and NMD prevalence between the 2 groups. Furthermore, we had 3 representative MPN patients who were complicated with coronary spasm, possibly caused by MPN-related endothelial dysfunction. We found that patients with MPN presented with endothelial dysfunction, which was related to the presence of genetic mutations and was sometimes associated with cardiovascular disease.