ABSTRACT Background: Anemia during childhood is one of the biggest public health problems worldwide, including Brazil. Insufficient or abnormal production of hemoglobin, loss of iron and excessive destruction of red blood cells are the most common causes of anemia. Among the reasons of anemia, iron deficiency accounts for 50% of anemia cases in developing countries. Affected individuals present a wide range of clinical problems, including delayed neuropsychomotor progression, impaired cellular immunity and reduction of intellectual capacity. This study aimed to evaluate the prevalence of anemia in children attending public schools in the metropolitan region of Curitiba, Paraná, Brazil. Method: A retrospective study was conducted of 409 children aged 8–12 years old included in an extension project of the Universidade Federal do Paraná. The results of complete blood count and hemoglobin electrophoresis of all children were evaluated. Anemia was considered when the hemoglobin levels were <11.5 g/dL. Results: The prevalence of anemia was found to be 2.2% of the population studied, with hypochromic microcytic anemia being the most common type. Seven children had sickle cell trait and one had β-thalassemia. Conclusion: The prevalence of anemia in this study was considered normal according the World Health Organization classification, which is different from the data found in other Brazilian regions.

OBJECTIVE: The aim of this study was to evaluate the protective effects of quercetin, rutin, hesperidin and myricetin against reactive oxygen species production with the oxidizing action of tert-butylhydroperoxide in erythrocytes from normal subjects and sickle cell anemia carriers treated with hydroxyurea. METHODS: Detection of intracellular reactive oxygen species was carried out using a liposoluble probe, 2',7'-dichlorfluorescein-diacetate (DCFH-DA). A 10% erythrocyte suspension was incubated with flavonoids (quercetin, rutin, hesperidin or myricetin; 30, 50, and 100 µmol/L), and then incubated withtert-butylhydroperoxide (75 µmol/L). Untreated samples were used as controls. RESULTS: Red blood cell exposure to tert-butylhydroperoxide resulted in significant increases in the generation of intracellular reactive oxygen species compared to basal levels. Reactive oxygen species production was significantly inhibited when red blood cells were pre-incubated with flavonoids, both in normal individuals and in patients with sickle cell anemia. Quercetin and rutin had the highest antioxidant activity, followed by myricetin and hesperidin. CONCLUSION: Flavonoids, in particular quercetin and rutin, showed better antioxidant effects against damage caused by excess reactive oxygen species characteristic of sickle cell anemia. Results obtained with patients under treatment with hydroxyurea suggest an additional protective effect when associated with the use of flavonoids.

A doença falciforme promove anemia hemolítica e oclusão dos pequenos vasos, causados pela presença de altas concentrações de hemoglobina S, cujas consequências incluem a produção aumentada de espécies reativas de oxigênio e diminuição da capacidade de defesa antioxidante. O objetivo desse estudo foi avaliar a ação protetora de um extrato padronizado de Ginkgo biloba (EGb 761), selecionado devido ao seu alto conteúdo de flavonóides e terpenóides, em eritrócitos de pacientes com anemia falciforme (HbSS, eritrócitos SS) submetidos ao estresse oxidativo usando terc-butil-hidroperóxido e 2,2-azobis-(amidinopropano)-diidrocloreto, in vitro. Índices de hemólise, glutationa reduzida, concentração de metemoglobina, peroxidação lipídica e espécies reativas de oxigênio foram determinados. Eritrócitos de pacientes com anemia falciforme apresentaram taxas aumentadas de oxidação da hemoglobina e peroxidação lipídica e a concentração de EGb 761 necessária para atingir o mesmo efeito antioxidante foi pelo menos duas vezes maior em relação aos eritrócitos normais (HbAA, eritrócitos AA), inibindo a formação de espécies reativas de oxigênio (IC50 de 13.6 µg/mL), prevenindo parcialmente a peroxidação lipídica (IC50 de 242.5 µg/mL) e prevenindo a hemólise (IC50 de 10.5 µg/mL). Portanto, EGb 761 possui um efeito benéfico no estado oxidativo dos eritrócitos SS. Entretanto, o EGb 761 não preveniu a oxidação da hemoglobina e da glutationa reduzida, nas concentrações examinadas.

Sickle cell disease promotes hemolytic anemia and occlusion of small blood vessels due to the presence of high concentrations of hemoglobin S, resulting in increased production of reactive oxygen species and decreased antioxidant defense capacity. The aim of this study was to evaluate the protective action of a standardized extract of Ginkgo biloba (EGb 761), selected due to its high content of flavonoids and terpenoids, in erythrocytes of patients with sickle cell anemia (HbSS, SS erythrocytes) subjected to oxidative stress using tert-butylhydroperoxide or 2,2-azobis-(amidinepropane)-dihydrochloride, in vitro. Hemolysis indexes, reduced glutathione, methemoglobin concentrations, lipid peroxidation, and intracellular reactive oxygen species were determined. SS erythrocytes displayed increased rates of oxidation of hemoglobin and membrane lipid peroxidation compared to normal erythrocytes (HbAA, AA erythrocytes), and the concentration of EGb 761 necessary to achieve the same antioxidant effect in SS erythrocytes was at least two times higher than in normal ones, inhibiting the formation of intracellular reactive oxygen species (IC50 of 13.6 µg/mL), partially preventing lipid peroxidation (IC50 of 242.5 µg/mL) and preventing hemolysis (IC50 of 10.5 µg/mL). Thus, EGb 761 has a beneficial effect on the oxidative status of SS erythrocytes. Moreover, EGb 761 failed to prevent oxidation of hemoglobin and reduced glutathione at the concentrations examined.