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| Thromb Haemost. 2004 Nov;92(5):1052-9. Related Articles, Links
Oxidative status of platelets in normal and thalassemic blood.
Amer J, Fibach E.
Chronic platelet activation may be involved in thromboembolic complications, a
leading cause of morbidity and mortality in beta-thalassemia. Oxidative stress,
with the generation of reactive oxygen species (ROS), is suspected to play a
role in the patho-physiology of thalassemia and cardiovascular disorders. In
the present study, we adapted flow cytometric techniques to measure oxidative
state markers, ROS generation and reduced glutathione (GSH) content in
platelets. Our results show that platelets obtained from beta-thalassemic
patients contain higher ROS and lower GSH levels than do platelets from normal
donors, indicating a state of oxidative stress. In the absence of any known
inherent abnormality in thalassemia platelets, this may be attributed to
continuous exposure to oxidative insults from extra-platelet sources. We found
that exposure of platelets to oxidants such as hydrogen peroxide and
tertbutylhydroperoxide or to the platelet activators thrombin, calcium
ionophore or phorbol myristate acetate stimulated the platelets' oxidative
stress. This was also increased by plasma of thalassemia patients, and
decreased following treatment of the plasma with the iron-chelator
Desferoxamin. Iron and hemin, the levels of which are augmented in plasma of
thalassemia patients, stimulated the platelets' oxidative stress. The oxidative
status of the platelets was also affected by red blood cells (RBC); it was
higher in normal platelets incubated with thalassemic RBC than with normal RBC.
Normal RBC stimulated with hydrogen peroxide had a greater effect on platelets
than did unstimulated RBC. The platelets' oxidative stress was ameliorated by
antioxidants such as N-acetyl-L-cysteine and vitamin C. Our findings indicate
that in thalassemia, platelets undergo a state of oxidative stress, leading to
their activation and potentially to thromboembolic consequences, and suggest
that this hypercoagulable state might be treated with antioxidants.
PMID: 15543333 [PubMed - in process]
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