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BACKGROUND: Oxidative stress may aggravate symptoms of hemolytic anemias such as beta-thalassemia. FoxO3 activation results in resistance to oxidative stress in fibroblasts and neuronal cell cultures. OBJECTIVE: The purpose of this research was to study FoxO3 gene expression and oxidative status in beta-thalassemia minor individuals. METHODS: Sixty-three subjects (42 apparently healthy individuals and 21 with beta-thalassemia minor) were analyzed at the Universidad Nacional de Tucumán, Argentina, between September 2013 and June 2014. A complete blood count, hemoglobin electrophoresis in alkaline pH and hemoglobin A2 levels were quantified. Moreover, thiobarbituric acid reactive species, erythrocyte catalase activity and iron status were evaluated. Beta-thalassemia mutations were determined by real-time polymerase chain reaction. FoxO3 gene expression was investigated by real-time reverse transcription-polymerase chain reaction using mononuclear cells from peripheral blood. RESULTS: Subjects were grouped as children (≤12 years), and adult women and men. The analysis of erythrocyte catalase activity/hemoglobin ratio revealed a significant difference (p-value <0.05) between healthy and beta-thalassemia minor adults, but no significant difference was observed in the thiobarbituric acid reactive species levels and FoxO3 gene expression (p-value >0.05). Thiobarbituric acid reactive species and the erythrocyte catalase activity/hemoglobin ratio were not significantly different on comparing the type of beta-thalassemia mutation (ß0 or ß+) present in carriers. CONCLUSIONS: The lack of systemic oxidative imbalance demonstrated by thiobarbituric acid reactive species is correlated to the observation of normal FoxO3 gene expression in mononuclear cells of peripheral blood. However, an imbalanced antioxidant state was shown by the erythrocyte catalase activity/hemoglobin ratio in beta-thalassemia minor carriers. It would be necessary to study FoxO3 gene expression in reticulocytes to elucidate the role of FoxO3 in this pathology.

RESUMO

ABSTRACT Background: Oxidative stress may aggravate symptoms of hemolytic anemias such as beta-thalassemia. FoxO3 activation results in resistance to oxidative stress in fibroblasts and neuronal cell cultures. Objective: The purpose of this research was to study FoxO3 gene expression and oxidative status in beta-thalassemia minor individuals. Methods: Sixty-three subjects (42 apparently healthy individuals and 21 with beta-thalassemia minor) were analyzed at the Universidad Nacional de Tucumán, Argentina, between September 2013 and June 2014. A complete blood count, hemoglobin electrophoresis in alkaline pH and hemoglobin A2 levels were quantified. Moreover, thiobarbituric acid reactive species, erythrocyte catalase activity and iron status were evaluated. Beta-thalassemia mutations were determined by real-time polymerase chain reaction. FoxO3 gene expression was investigated by real-time reverse transcription-polymerase chain reaction using mononuclear cells from peripheral blood. Results: Subjects were grouped as children (≤12 years), and adult women and men. The analysis of erythrocyte catalase activity/hemoglobin ratio revealed a significant difference (p-value <0.05) between healthy and beta-thalassemia minor adults, but no significant difference was observed in the thiobarbituric acid reactive species levels and FoxO3 gene expression (p-value >0.05). Thiobarbituric acid reactive species and the erythrocyte catalase activity/hemoglobin ratio were not significantly different on comparing the type of beta-thalassemia mutation (β0 or β+) present in carriers. Conclusions: The lack of systemic oxidative imbalance demonstrated by thiobarbituric acid reactive species is correlated to the observation of normal FoxO3 gene expression in mononuclear cells of peripheral blood. However, an imbalanced antioxidant state was shown by the erythrocyte catalase activity/hemoglobin ratio in beta-thalassemia minor carriers. It would be necessary to study FoxO3 gene expression in reticulocytes to elucidate the role of FoxO3 in this pathology.

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RESUMO

Most common microcytic hypochromic anemias are iron deficiency anemia (IDA) and ß-thalassemia trait (BTT), in which oxidative stress (OxS) has an essential role. Catalase causes detoxification of H2O2 in cells, and it is an indispensable antioxidant enzyme. The study was designed to measure erythrocyte catalase activity (ECAT) in patients with IDA (10) or BTT (21), to relate it with thalassemia mutation type (ß (0) or ß (+)) and to compare it with normal subjects (67). Ninety-eight individuals were analyzed since September 2013 to June 2014 in Tucumán, Argentina. Total blood count, hemoglobin electrophoresis at alkaline pH, HbA2, catalase, and iron status were performed. ß-thalassemic mutations were determined by real-time PCR. Normal range for ECAT was 70,0-130,0 MU/L. ECAT was increased in 14% (3/21) of BTT subjects and decreased in 40% (4/10) of those with IDA. No significant difference (p = 0,245) was shown between normal and BTT groups, while between IDA and normal groups the difference was proved to be significant (p = 0,000). In ß (0) and ß (+) groups, no significant difference (p = 0,359) was observed. An altered ECAT was detected in IDA and BTT. These results will help to clarify how the catalase activity works in these anemia types.

RESUMO

Differential scanning calorimetry (DSC), mixed monomolecular layers and fluorescence spectroscopy techniques were applied to investigate the effect of thyroid hormones (THs) on the biophysical properties of model membranes. We found that both 3,3',5-triiodo-L-thyronine (T3) and 3,5,3',5'-tetraiodo-L-thyronine (T4) induce a broadening of the calorimetric main phase transition profile and reduce the transition enthalpy in liquid-crystalline state of dipalmitoylphosphatylcholine (DPPC) multilamellar vesicles. Tm changes from 41 °C to 40 °C compared to pure DPPC. When the experiments were done by adding THs to preformed multilamellar vesicles a second broader component in the DSC scan also appears at 20 min of incubation and becomes gradually more prominent with time, indicating a progressive alteration of lipid phase induced by THs. Analysis of surface pressure-molecular area isotherms in mixed monolayers of THs with either DPPC or 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) at air-water interface indicated a reduction in molecular area for THs/lipid mixtures at all surface pressures. A substantial decrease in surface potential in mixed lipid/THs monolayers at all surface pressures were observed for both phospholipids without affecting the mixed monolayer integrity. The data of mixed lipid/THs behavior support the establishment of lateral miscibility. Alterations of bidimensional liquid expanded→liquid condensed phase transition observed for DPPC/THs mixed monolayers are compatible with the changes observed in DSC. The transverse movement of THs and the decrease of dipole potential were also observed in single unilamellar vesicles by using appropriate fluorescent probes.

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