Vitamin E correlates inversely with non-transferrin-bound iron in sickle cell disease

The association of transfusion status with antioxidant enzymes and malondialdehyde level in Nigerians with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) often leads to chronic hemolytic anemia of varying severity, and blood transfusion may be employed in the management of SCD complications.

OBJECTIVE

The aim of the study was to evaluate the effect of blood transfusion on the activities of some antioxidant enzymes as well as lipid peroxide and to relate transfusion status to these enzymes and malondialdehyde (MDA) in SCD patients.

MATERIALS AND METHODS

Glutathione peroxidase (GPX), superoxide dismutase, catalase, MDA, and lipoproteins were assayed in 87 SCD and 20 age- and sex-matched subjects with normal hemoglobin. Of the 87 SCD patients, 30 had multiple transfusions, 21 had been transfused once while 36 had not been transfused within the last 3 months.

RESULTS

Statistically significant decrease in the mean levels of GPX (P = 0.045) and Cu/Zn SOD (P = 0.001) and increased (P = 0.001) MDA were observed in the transfused compared to non-transfused patients. Similarly, significant decrease (P = 0.001) in Cu/Zn SOD and increase (P = 0.01) in MDA were observed in multi transfused compared to those who had been transfused once. Transfusion status correlated (P <0.047) inversely with Cu/Zn SOD and positively with MDA.

CONCLUSION

Reduced activity levels of serum antioxidant enzymes and increased mean levels of MDA were observed in transfused compared to non-transfused SCD patients and these changes correlated with transfusion status.

Endothelium-dependent and endothelium-independent vasodilatation of the cutaneous circulation in sickle cell disease

BACKGROUND

Whilst there is evidence of endothelial dysfunction in sickle cell disease (SCD), whether this affects regulation in the microcirculation is not known.

METHODS

 We studied 19 patients with SCD, eight with sickle cell-haemoglobin C (HbSC), 11 with homozygous sickle cell (HbSS) disease and 11 matched control subjects with normal haemoglobin genotype (HbAA). Vasodilator responses were evoked by iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) in finger and forearm, cutaneous red cell flux (RCF) being measured by laser Doppler fluximetry.

RESULTS

Increases in RCF evoked in the finger by ACh were not different between SCD and HbAA subjects (P = 0·789), but were smaller in patients with HbSS than HbSC (P < 0·05). By contrast, increases in RCF evoked in forearm by ACh were greater in SCD than HbAA subjects (P < 0·05) and similar in patients with HbSC and HbSS. Increases in RCF evoked by SNP did not differ between patients with SCD and HbAA subjects in finger or forearm.

CONCLUSIONS

Our results indicate that endothelium-dependent cutaneous vasodilatation is augmented in forearm of patients with SCD relative to HbAA subjects, but impaired in the finger of SCD patients with the more severe HbSS genotype. Thus, endothelial dysfunction associated with SCD is not accompanied by generalised impairment in endothelium-dependent dilatation, but with more localised impairment that includes the fingers of patients with HbSS.

Oxidant, antioxidant status and metabolic data in patients with beta-thalassemia

BACKGROUND

In beta-thalassemia major impaired biosynthesis of beta globin leads to accumulation of unpaired alpha globin chain. An iron overload, usually observed, generates oxygen-free radicals and peroxidative tissue injury.

AIM

To investigate hematological parameters, oxidative stress and the antioxidant capacity in beta-thalassemia patients compared to control subjects in order to determine their impact in several organs functions.

METHODS

This study was conducted on 56 beta-thalassemia major patients compared to 51 healthy subjects. We determined metabolic parameters (glycaemia, lipid parameters, electrolytes, iron indices, hepatic, renal and heart functions tests), plasmatic thiobarbituric acid reactive substances (TBARS), plasmatic peroxyl radical trapping potential (TRAP), plasmatic superoxide dismutase (SOD), erythrocyte gluthathione peroxidase (GPX), plasmatic vitamin E, vitamin A and trace elements.

RESULTS

Except triglycerides, lipid fractions were significantly decreased in beta-thalassemia compared to controls. Serum ferritin, iron, TBARS concentrations, SOD and GPX activities were significantly increased. But TRAP, vitamin E and zinc concentrations were significantly decreased.

CONCLUSION

Our findings confirm the peroxidative status generated by iron overload in beta-thalassemia major patients and highlight the rapid formation of marked amounts of TBARS and the increase of SOD and GPX activity. Our study suggested that in beta-thalassemia the first organ impaired is the liver.

Platelet activation and endothelial cell dysfunction in sickle cell disease is unrelated to reduced antioxidant capacity

Possible pathogenetic processes in sickle cell disease include antioxidants, endothelial and platelet changes, and hypercoagulability. Hypothesizing relationships between these processes, we recruited 47 young adult patients (mean age 19 years) with homozygous sickle cell disease and 40 age-, race- and sex-matched healthy controls and measured plasma markers representative of these processes. We found raised plasma von Willebrand factor (P = 0.001) and intercellular adhesion molecule (P = 0.016, both marking endothelial perturbation, but the latter also marking inflammation), raised soluble P selectin (P = 0.002) (marking platelet activation) and inflammation marker C reactive protein (P = 0.021), but reduced antioxidant capacity (P = 0.002) in patients compared with controls. There was no difference in fibrinogen and there was no significant correlation between any of the indices. Our data suggest that changes in endothelial and platelet function in sickle cell disease are unrelated to reduced antioxidant capacity.

Reduced vitamin E antioxidant capacity in sickle cell disease is related to transfusion status but not to sickle crisis

In homozygous sickle cell disease (SCD), decreased serum Vitamin E is present. Excessive transfusions may lead to iron overload. We hypothesised a relationship between the two and found that Vitamin E type antioxidant capacity was significantly lower in 30 SCD patients than in 30 age- and sex-matched controls (P < 0.001). Antioxidant capacity was lower in 10 transfused patients compared with 20 non-transfused patients (P < 0.001). Transfusional iron overload in SCD may increase the potential for oxidative damage, and low antioxidant capacity may compound this effect.