Reduced antioxidant capacities in platelets from patients with autoimmune thrombocytopenia purpura (ITP)

Abstract

Autoimmune thrombocytopenic purpura (ITP) is characterized by an abnormally low platelet count and bleeding risks. The exact triggering event remains elusive. Oxidative stress may play a role in several autoimmune diseases. A direct link between platelets in ITP and oxidative stress has not yet been addressed. The intracellular platelet antioxidant capacity (AOC) in ITP patients in the active phase (n = 24) and remission (n = 12), and 44 healthy controls were analysed with 2',7'-dichlorodihydrofluorescein diacetate, and in combination with hydrogen peroxide. Enzyme activities (EA) of serum glutathione peroxidase (GPx), glutathione reductase (GRed) and catalase (CAT) were investigated colourimetrically in patients and controls. The AOC of ITP patients in the active phase was drastically reduced, with significantly high mean fluorescence intensity values. Higher GPx activity was observed in both active phase and remission in comparison to healthy controls (p < 0.001), with greater activity observed in active ITP than remission (p = 0.001). However, GRed EA was not elevated indicating that reduced glutathione (GSH) is not comparably recovered as consumed, leading to a decreased bioavailability of GSH and increased oxidative stress. These results suggest that oxidative stress is implicated in active ITP and may play a crucial role in its pathophysiology.

Oxidant/antioxidant status in children and adolescents with immune thrombocytopenia (ITP) and the role of an adjuvant antioxidant therapy

“…The higher levels of MDA in patients with ITP might suggest the role of lipid peroxidation in the pathogenesis of ITP and can explain lowering of antioxidants as a result of antioxidant consumption.Lipid peroxidation in platelets may alter platelet metabolism . The free oxygen molecule could attack polyunsaturated fatty acids forming lipid peroxyl radicals causing cell death.…”

Antioxidant Status and Oxidative Stress in Patients with Chronic ITP

“…A direct link between platelets in ITP and oxidative stress has not yet been addressed. Kamhieh-Milz et al [25] found that the intracellular platelet antioxidant capacity (AOC) of ITP patients in the active phase was drastically reduced, with significantly high mean fluorescence intensity values. Higher hydroperoxide glutathione peroxidase (GPx) activity was observed in both active phase and remission in comparison with healthy controls, with greater activity observed in active ITP than remission.…”

Oxidative Stress Is Predominant in Female but Not in Male Patients with Autoimmune Thrombocytopenia

“…Recently, Jin and coworkers reported on serum nitrogen monoxide (NO), glutathione (GSH), glutathione disulphide (GSSG), MDA, total antioxidant status, total oxidant status, superoxide dismutase, and catalase and glutathione peroxidase levels in adult ITP patients, with strong correlations observed between these parameters and platelets counts [25]. We were the first to investigate the intracellular generation of ROS in platelets in order to characterize platelet AOCs and identified a reduced AOC of platelets from AITP patients compared to healthy donors, suggesting that platelets are under the attack of a systemic OS [26]. The aim of this study was to investigate systemic OS and AOCs of AITP patients.…”