Genetic Regulation of Redox Balance in ß-Thalassemia Trait.

ß-Thalassemia (ß-thal) trait is a heterogeneous group of genetic defects leading to decreased ß-globin production, ineffective erythropoiesis, and oxidative stress. The aim is to evaluate the cytoprotective response, at transcriptional and systemic levels, of the variations of global redox balance in ß-thal trait patients. Sixty-six subjects (40 healthy and 26 with ß-thal trait) were analyzed at the Universidad Nacional de Tucumán, Tucumán, Argentina, between 2016 and 2017. The following parameters were evaluated: complete blood count, iron status, hemoglobin (Hb) electrophoresis, Hb A2, thiobarbituric acid reactive species (TBARS), serum catalase (CAT), and superoxide dismutase (SOD) activity, FOXO3a, NRF2, SOD, PRDX2, CAT, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) gene expression. The ß-thal trait group showed a decrease in Hb levels, MCV, and MCH with higher TBARS levels. The SOD activity was significantly increased by 32.0% in ß-thal trait patients respect to the control group. Relative expression of NRF2 was 4.7-fold higher in ß-thal trait than in the control group, while FOXO3a expression was similar in both groups. The SOD, PRDX2, and proinflammatory cytokines transcriptional expression was significantly upregulated in ß-thal trait patients. This is the first study on the genetic regulation of redox balance in ß-thal trait patients in which interesting modifications were observed in the transcript levels of some redox regulators that could be associated with changes in the erythrocyte proteome in this disorder. A better understanding of the pathophysiological mechanisms present in these heterozygous patients would allow adequate therapy in situations such as growth, pregnancy, or high performance sports, favoring a personalized treatment.

Molecular characterization and phenotypical study of ß-thalassemia in Tucumán, Argentina.

The main hereditary hemoglobin (Hb) disorder in Argentina is ß-thalassemia (ß-thal). Molecular studies performed in the center of the country exhibited a marked prevalence of the codon 39 (C > T) and IVS-I-110 (G > A) mutations. The northwest region of Argentina has a different demographic history characterized by an important Spanish influx. Seventy-one ß-thal carriers attending the Instituto de Bioquímica Aplicada, Tucumán, Argentina, were investigated for ß-globin gene mutations by real-time polymerase chain reaction (RT-PCR). To examine the genotype-phenotype relationship, mean corpuscular volume (MCV), mean corpuscular Hb (MCH) and Hb A2 were measured. In order to recognize ß-thal, Mentzer Index, Shine & Lal and Red Cell Distribution Width Index (RDWI), were calculated. The ethnic background of subjects revealed that 82.0% of the population was of Italian, Spanish and Arab origin. Seven mutations were detected: codon 39 (45.0%), IVS-I-1 (G > A) (22.5%), IVS-I-110 (16.3%), IVS-II-1 (G > A) (4.1%), IVS-I-1 (G > T) (2.0%), IVS-I-6 (T > C) (2.0%) and IVS-II-745 (G > C) (2.0%). In three families (6.1%), ß-thal mutations were not determined. These results differed from other Argentinian studies because at present codon 39 and IVS-I-1 are the most prevalent; MCV, MCH and Hb A2 did not correlate with the type of mutation (ß(0)/ß(+)). Values of MCV (67.0 fL) and Hb A2 (4.85%) were unable to discriminate between them. Significant differences (p < 0.05) in MCV, MCH and Shine & Lal were observed between the undetermined group and the three most common mutations. These data show different patterns of ß-thal mutations in the center and northwest regions of Argentina. Differences might represent the influence of Spanish immigration.