Avaliação da capacidade de absorção de ferro em crianças com anemia falciforme

Abstract

Sickle cell anemia (SCA) is a hemoglobinopathy characterized by inflammation, vaso-occlusion phenomena and chronic hemolysis. Hepcidin is the hormone mainly responsible for iron homeostasis and intestinal absorption. Recents studies have observed that iron load influences in serum hepcidin concentrations. To establish a safe nutritional approach, the estimation of the iron absorption capacity needs to be better understood, especially for children, whose have a high rate of growth and development. Evaluate the iron absorption capacity in children with sickle cell anemia. Experimental study, carried out with 14 children (Median = 8.0 years; Interquertile range: 7 - 9 years). Three groups participated in the study: the control group, comprised of individuals without SCA (n=2); those with the disease but without iron overload (n=8); and those with the disease and iron overload (n=4). The evaluation of the iron absorption capacity was performed by marking a standardized food (100 mL of orange juice) with the stable isotope 57Fe (5 mg). Blood samples were colected at baseline and 14 days after ingestion of the isotope and the isotopic relationship between 56Fe/57Fe was provided by inductively coupled plasma mass spectrometry (ICP-MS). In the group of children with SCA without iron overload, a moderate positive correlation was found between ferritin and hepcidin (r = 0.762; p <0.05) and a strong negative correlation between ferritin and 57Fe absorption percentage (r = - 0.962; p <0.05). In the same group, the HbS percentual was strongly correlated with the percentage of iron absorption (r = 0.976; p <0.05). The percentage of 57Fe absorption did not correlate with hepcidin and liver iron concentration in any of the groups. The 57Fe absorption percentage was statistically different among the three groups studied (3.9%, children with SCA and iron overload; 18.2%, children with SCA and without iron overload; and 12.67%, children without the disease). The percentage of intestinal iron absorption found in children with SCA and iron overload suggests that the recommendations for restriction of iron source foods, to which these individuals are frequently submitted, may not be necessary.