title: The influence of hydroxyurea on oxidative stress in sickle cell anemia.
abstract: OBJECTIVE
  The oxidative stress in 20 sickle cell anemia patients taking hydroxyurea and 13 sickle cell anemia patients who did not take hydroxyurea was compared with a control group of 96 individuals without any hemoglobinopathy.
  
  
  METHODS
  Oxidative stress was assessed by thiobarbituric acid reactive species production, the Trolox-equivalent antioxidant capacity and plasma glutathione levels.
  
  
  RESULTS
  Thiobarbituric acid reactive species values were higher in patients without specific medication, followed by patients taking hydroxyurea and the Control Group (p < 0.0001). The antioxidant capacity was higher in patients taking hydroxyurea and lower in the Control Group (p = 0.0002 for Trolox-equivalent antioxidant capacity and p < 0.0292 for plasma glutathione). Thiobarbituric acid reactive species levels were correlated with higher hemoglobin S levels (r = 0.55; p = 0.0040) and lower hemoglobin F concentrations(r = -0.52; p = 0.0067). On the other hand, plasma glutathione levels were negatively correlated with hemoglobin S levels (r = -0.49; p = 0.0111) and positively associated with hemoglobin F values (r = 0.56; p = 0.0031).
  
  
  CONCLUSIONS
  Sickle cell anemia patients have high oxidative stress and, conversely, increased antioxidant activity. The increase in hemoglobin F levels provided by hydroxyurea and its antioxidant action may explain the reduction in lipid peroxidation and increased antioxidant defenses in these individuals.
authors: Universidade Estadual Paulista - UNESP, São José do Rio Preto, SP, Brazil.
authors: Lidiane de Souza
authors: Lde S
authors: Torres
authors: Danilo Grünig Humberto
authors: DG
authors: da Silva
authors: Edis
authors: E
authors: Belini Junior
authors: Eduardo Alves
authors: EA
authors: de Almeida
authors: Clarisse Lopes de Castro
authors: CL
authors: Lobo
authors: Rodolfo Delfini
authors: RD
authors: Cançado
authors: Milton Artur
authors: MA
authors: Ruiz
authors: Claudia Regina
authors: CR
authors: Bonini-Domingos
keywords: Anemia, sickle cell; Hemoglobinopathies; Hydroxyurea; Oxidative stress