The evaluation of oxidative stress in patients with essential thrombocythemia treated with risk-adapted therapy

Abstract

Introduction. Essential thrombocythemia (ET) is a clonal disorder of the hematopoietic stem cells characterized by persistent thrombocytosis in the peripheral blood, excessive proliferation of megakaryocytes and minor reticulin fibrosis in the bone marrow. It seems that oxidative stress is involved in the development and progression of ET. Objective. To evaluate oxidative stress levels in ET patients treated with risk-adapted therapy. Material and methods. 62 ET patients and 20 controls (informed consent obtained) were enrolled. ET diagnosis was based on WHO criteria (2016 revised). Reactive oxygen species (ROS) levels and the total antioxidant capacity (TAC) were evaluated at time of diagnosis and after 6 months of risk-adapted therapy. ET patients were divided into 3 groups and treated with risk–adapted therapy: a low risk group, treated with low doses of aspirin 75 mg/day or watch-and-wait; an intermediate risk group treated with low doses of aspirin 100 mg/day or low-dose aspirin + cytoreductive treatment; a high-risk group, treated with low doses of aspirin and cytoreductive treatment (hydroxyurea) or platelet-lowering agents (anagrelide). Results. ET patients had at diagnosis higher ROS levels and a lower TAC vs. controls. After 6 months of risk-adapted therapy, ROS levels decreased and TAC increased. No significant differences were seen between the effect of hydroxyurea and the effect of anagrelide on oxidative stress levels. Conclusions. ROS levels are increased and TAC is decreased in ET patients vs. controls. These values depend on the risk group assigned to the patient. Risk-adapted therapy was useful to reduce ROS levels and increase TAC.

Keywords

• essential thrombocythemia
• oxidative stress
• reactive oxygen species
• total antioxidant capacity
• risk-adapted therapy.