Evaluation of hydroxyurea genotoxicity in patients with sickle cell disease

Abstract

Objective: To evaluate the induction of DNA damage in peripheral blood mononuclear cells of patients with sickle cell disease, SS and SC genotypes, treated with hydroxyurea.

Methods: The study subjects were divided into two groups: one group of 22 patients with sickle cell disease, SS and SC genotypes, treated with hydroxyurea, and a Control Group composed of 24 patients with sickle cell disease who were not treated with hydroxyurea. Peripheral blood samples were submitted to peripheral blood mononuclear cell isolation to assess genotoxicity by the cytokinesis-block micronucleus cytome assay, in which DNA damage biomarkers - micronuclei, nucleoplasmic bridges and nuclear buds - were counted.

Results: Patients with sickle cell disease treated with hydroxyurea had a mean age of 25.4 years, whereas patients with sickle cell disease not treated with hydroxyurea had a mean age of 17.6 years. The mean dose of hydroxyurea used by the patients was 12.8mg/kg/day, for a mean period of 44 months. The mean micronucleus frequency per 1,000 cells of 8.591±1.568 was observed in the Hydroxyurea Group and 10.040±1.003 in the Control Group. The mean frequency of nucleoplasmic bridges per 1,000 cells and nuclear buds per 1,000 cells for the hydroxyurea and Control Groups were 0.4545±0.1707 versus 0.5833±0.2078, and 0.8182±0.2430 versus 0.9583±0.1853, respectively. There was no statistically significant difference between groups.

Conclusion: In the study population, patients with sickle cell disease treated with the standard dose of hydroxyurea treatment did not show evidence of DNA damage induction.

Figure 1. Evaluation of the genotoxicity effect by means of cytokinesis block micronucleus cytome assay in peripheral blood mononuclear cells of patients with sickle cell disease SS or SC, treated with hydroxyurea (HU Group; n=22) and not treated with this drug (Control Group; n=24). Mean frequency of micronuclei (MN): (A) nucleoplasmic bridges (NPBs); (B) nuclear buds (NBUDs); (C) and Nuclear Division Index (NDI); (D) in binuclear cells (BN). There was no significant difference between the groups studied (p>0.05), according to the paired t test

Figura 1. Avaliação do efeito de genotoxicidade por meio do ensaio de micronúcleo citoma com bloqueio da citocinese em células mononucleares de sangue periférico de pacientes com doença falciforme SS ou SC tratados com hidroxiureia (Grupo HU; n=22) e não tratados com esse fármaco (Grupo Controle; n=24). Frequência média de micronúcleos (MN): (A) pontes nucleoplasmáticas (NPBs); (B) brotos nucleares (NBUDs); (C) e Índice de Divisão Nuclear (IDN); (D) em células binucleadas (BN). Não houve diferença significativa entre os grupos estudados (p>0,05) de acordo com o teste t pareado