Avaliação dos níveis séricos de malonaldeído (MDA), óxido nítrico (NO) e lactato desidrogenase láctica (LDH) na anemia falciforme e suas correlações com o uso de hidroxiuréia

Abstract

The sickle-cell disease (SCD) is characterized by hemolytic chronic anemia and with vase-occlusive phenomena, followed by target organs which are responsible for the mortality associated with this disease. The vase-occlusive phenomenon is associated with the inflammatory process unleashed by the polymerization of deoxygenated HbS, which favors the polymerization of erythrocytes in the microcirculation and the subsequent obstruction of endothelia light. Several evidences suggest that the reduction of the bioavailability of the nitric oxide (NO) can be a factor to favor the vase-occlusion and that the free radicals produced give rise to the lipidic peroxidation and the subsequent production of the abnormal quantities of malonaldehyde (MDA), which induce the permeability of the red cell membrane. Among the genetic factors that modulate the clinic of the AF, there is the HbF levels. The hydroxyurea (HU) is used in the treatment of SCD and apart from increasing the HbF levels it also seems to contribute as a nitric oxide donator. In this context, the present work aims to evaluate the oxidative stress by means of seric dosage of the MDA and to determinate the levels of NO and lactate desidogenase lactica (LDH) in patients with SCD by means within the Walter Cantídeo University Hospital (HUWC) and to correlate with the use of HU. This way, it was used 65 samples of peripheral blood of adult patients with AF with either HU or not, and a control group was composed by 20 donors of the blood bank with HbAA. The levels of NO, MDA and LDH were determined by biochemical methods. The participants of the research were selected in the Center of Hematology and Hemotherapy of Ceará State (HEMOCE). All the participants have signed a document stating free consent and approval (TCLE) and they were submitted to a previously elaborated questionnaire. The obtained data were expressed as averages ± pattern deviation and analyzed by using a statistics software SPSS®15.0, using Pearson and Spearman correlation coefficients for the study of the correlations among MDA, NO, LDH, HbF and Hb. In order to compare the three groups through the levels of MDA, NO and LDH, the results were obtained by means of deviance analysis (ANODEV). It has been observed a majority of females and fallow race (group I) and black (group II), in which the most part of these patients have ages in the range of 20-35 (group I) and 20-40 (group II) and come from Ceará State. Most of them did not smoke, drink alcohol nor use vitamin supplements (C and E). The levels of MDA in the three groups are all different, i. e., the control group showed an average level of MDA higher than group II, and the later higher than that of the group one. It was not verified difference in the seric levels of NO in relation to the use of HU. In the three groups, it was observed that only the control group is different, showing an average much lower than those of the other two groups of patients regarding the levels of LDH. It was also observed a correlation inversely proportional between the two levels of NO and HbF for the group I, while in the group II there was no correlation. Regarding to the concentration of Hb, there was no correlation both in the group I and in the group II, with levels of NO. There was no significantly correlation among the levels of MDA, Hb and HbF for the studied groups. It was found a correlation inversely proportional between the levels of LDH and Hb for the group I. It was observed accentuated levels of MDA in patients of group II who have made two or more transfusions throughout the year, who had leg ulcers and who had three or more vase-occlusive crises form both the groups. It was found no relation of NO with the clinic variables. CONCLUSÃO: Our results have shown that patients who use HU are not protected against lipidic peroxidation, hemolysis and consume of available NO