Estudos diagnóstico e avaliativo de biomarcadores de dislipidemias em indivíduos com doença falciforme acompanhados nos Hemocentros de Governador Valadares e Uberaba da Fundação Hemominas

Abstract

Hypocholesterolemia and hypertriglyceridemia have been documented in sickle cell disease (SCD) for many years, but the causes and effects on pathophysiology still need to be clarified. In addition, reports on genetic markers related to lipid metabolism that explain the variation of lipid levels and their associations with subtypes of hemolysis and vaso-occlusion and clinical variability of SCD have not been published to date. The overall objective of the study was to investigate whether dyslipidemia and single nucleotide polymorphisms (SNPs) in genes linked to lipid and inflammatory changes would be associated with changes in hematological, biochemical and clinical variables in children and adolescents with the two most frequent forms of SCD, sickle cell anemia (HbSS) and hemoglobinopathy SC (HbSC). The population consisted of 155 individuals born between 2001 and 2010, with a mean age of 12.54 years, being 55.5% male, followed in the Regional Hemocenters of Governador Valadares and Uberaba of the Hemominas Foundation. A conrole group consisting of 40 children without SCD with a mean age of 12.98 years was also included for comparison with lipid data. Data collection on medical records, biochemical tests, genotyping of ANGPTL4, APOA5, ZNF259 and TNFASNPs, alpha-thalassemia screening and assessment of hydroxyurea (HU) use were performed. There were associations between the variables investigated and, of these, with the occurrence of clinical events of the SCD. For these purposes chi-square, Mann-Withiney, Student's T-Test, ANOVA, Kruskal-Wallis and correlations with the Spearman test were applied. Statistical significance was set at P <0.05. Among the findings, we found worse markers of hemolysis and inflammation in HbSS individuals in relation to HbSC. Hypocholesterolemia (HDL <40 mg / dL) was found in 64.52% of the SCD population, with a significant difference between individuals and controls, with no difference between HbSS and HbSC. Individuals with SCD that had HDL greater than 40 mg / dL had higher levels of APOA1 and lower total cholesterol and triglycerides. Hypertriglyceridemia (TG> 100 mg / dL up to 10 years and> 130 mg / dL over 10 years) present in only 8.51% of SCD patients showed no significant difference between the HbSS and HbSC groups and was associated with high levels of the LDH enzyme. In the HbSS subjects the low HDL levels were in a higher proportion when compared to the HbSC group. The use of HU in the HbSS group did not interfere with lipid levels. The rare variant of the ANGPTL4 gene rs116843064 (G> A) in the dominance model was associated with reduction of global leukocytes and monocytes and increase of apolipoprotein A1 and total cholesterol in subjects with DF. The polymorphism of ZNF259 rs964184 (c.724C> G) was associated with increased markers of hemolysis/ inflammation (total leukocytes, reticulocytes and total and direct bilirubin) and had a dose-dependent effect on direct bilirubin levels. The lower frequency variant (-308A) of TNFA rs1800629 was associated with a 73% increase in direct bilirubin levels. Alpha-thalassemia co-inheritance in both HbSS and HbSC groups reduced MCV andMCH, but did not influence HbF, reticulocyte, bilirubin or lipid profile levels.In conclusion, hypocholesterolemia was characterized by low levels of HDL in both groups of HbSS and HbSC and the therapeutic use of hydroxyurea or the coexistence of deletion alleles of HBA genes does not appear to influence this dyslipidemic condition. Among the polymorphisms studied, that of ZNF259 rs964184 was the only one associated with lipid levels in SCD. Our study is the first to show that the lower frequency variants of ZNF259 rs964184 and TNFA rs1800629 are associated with hyperbilirubinemia in SCD.