Activity of antioxidant enzymes in children from families at high risk of premature coronary heart disease

Assessment of antioxidant system status before and after operation in neonates with congenital heart disease

Background/Aim

Oxidative stress is considered to have a significant role in the development of cardiovascular diseases (CVDs) as well as many other diseases. Therefore, the purpose of the study is to evaluate the antioxidant system status at pre- and post-operative period in newborns with congenital heart disease (CHD) requiring operation.

Materials and Methods

Fifty CHD patients participated in this research. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and thiobarbituric acid reactive substances (TBARS) levels were studied in blood samples. RACHS-1 score, blood lactate levels, and hypoxic events were also recorded. Comparisons of antioxidant system parameters were conducted at pre- and post-operative periods and also between exitus and discharged groups.

Results

GPx activity and TBARS levels were significantly higher in the pre-operative period than post-operative period though the other antioxidant enzymes were not altered. In pre-operative period, GPx activity was low in addition to rarer hypoxic events in the discharged group. Also, a negative correlation was found between SOD and GPx activities in pre-operative period.

Conclusion

The results provide fundamental data showing the lowered GPx activity and TBARS levels considered as sensitive oxidative biomarkers after the operation. It was assumed that antioxidant system parameters might show changes after the operation, and GPx is prominent for resistance to hypoxic conditions. Post-operative reduction of GPx and TBARS levels is significant for evaluating the antioxidant system alterations after the operation. However, further investigations follow long-term duration for post-operative monitoring to estimate how antioxidant system status changes to improve the treatment of the health condition.

Oxidative stress in hypertensive children before and after 1 year of antihypertensive therapy

BACKGROUND

The relation between primary hypertension (PH), target organ damage (TOD) and oxidative stress (SOX) is not known.

METHODS

We assessed SOX in 86 children with PH before and after 12 months of standard non-pharmacological and pharmacological therapy based on renin-angiotensin system blockade.

RESULTS

Patients with left ventricular hypertrophy (LVH) and with carotid intima-media thickness (cIMT) >2SDS had higher thiobarbituric acid reactive substances (TBARS) concentrations in comparison to patients without LVH or with normal cIMT. Patients with metabolic syndrome (MS) had lower activity of gluthatione peroxidase, higher asymmetric dimethyloarginine (ADMA) and oxidized LDL cholesterol (oxyLDL) in comparison to patients without MS. TBARS correlated with left ventricular concentric hypertrophy, cIMT, albuminuria and SBP/24 h. ADMA and oxyLDL correlated with CRP and TG/HDL ratio. After 1 year of antihypertensive treatment blood pressure, TOD and prevalence of MS decreased. TBARS decreased and glutathione concentrations increased. The decrease of TBARS concentration correlated with the decrease of body mass index (BMI). Decrease of oxyLDL and ADMA correlated with increased insulin sensitivity, however markers of SOX did not correlate with BP decrease.

CONCLUSION

SOX in children with PH correlates with TOD, metabolic abnormalities, changes in fat amount and improvement of insulin sensitivity, but not with BP decrease.

Antioxidant-rich oral supplements attenuate the effects of oral iron on in situ oxidation susceptibility of human feces

Prophylactic doses of 120 mg of iron (Fe) are commonly used to prevent Fe-deficiency anemia in vulnerable populations, especially in developing countries. Evidence shows that residual Fe in the large bowel may alter the normal antioxidant capacity of the fecal stream. Our objective was to evaluate the effect of dietary antioxidants from the Carotino Tocotrienol-Carotene Mixed Concentrate (CTCMC) on the depletion of fecal antioxidant capacity by oral Fe supplementation. In total, 17 healthy male adults participated in the 2 phases of the study, 5 in the pilot study and 12 in the definitive intervention trial. Participants received different treatments, separated by washout periods. These included: 120 mg Fe; 120 mg Fe and refined palm oil (FeOil); and 120 mg Fe in refined palm oil combined with 1 of 2 dosages (0.4 g and 0.8 g) of CTCMC/5 mL of refined palm oil (CTCB and CTCA treatments, respectively). Fecal samples were collected and analyzed to quantify the products of hydroxyl radical attack on salicylic acid (2,5 dihydroxybenzoic acid, 2,3-dihydrobenzoic acid, and catechol) at baseline and after active supplementation. Fe supplementation in either form (Fe or FeOil treatments) increased the concentrations of hydroxylated compounds in fecal samples. The production of hydroxylated compounds was significantly lower in treatments CTCB and CTCA than in the FeOil reference. Baseline antioxidant capacity state was virtually restored with dietary carotenoids and tocotrienols from the CTCMC. In conclusion, dietary antioxidants can reverse the depletion of fecal antioxidant capacity induced by oral Fe supplements.

Influence of dietary lipids on the erythrocyte antioxidant status of hypercholesterolaemic children

The aim of this work was to examine the effect of dietary lipid intakes on the biomarkers of red cell antioxidant status in hypercholesterolaemic children. The study population included 34 children (18 boys and 16 girls) with cholesterol levels > or =5.2 mmol/l and 16 normolipidaemic children (9 boys and 7 girls) between 6 and 12 years of age. The status of the erythrocyte antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and reduced glutathione (GSH) were estimated spectrophotometrically. Dietary intake was assessed by 24-h recall and seven-day records. The hypercholesterolaemic children showed a decreased activity of antioxidant enzymes in relation to the control group. There was a negative correlation between energy intake and the activity of antioxidant enzymes (SOD and CAT) and GSH levels. Cholesterol intake was inversely correlated with CAT and GPx activity and GSH levels. The intake of polyunsaturated fat was positively correlated with the GPx activity. A decrease in the fat content of the diet for 6 months was proposed and 15 children followed the diet strictly. The activities of antioxidant enzymes in these children were significantly higher after the low-fat diet; the greatest increment was noted in the activity of GPx (91% with respect to the initial values), SOD was increased by 44% and CAT by 70%. We conclude that the intake of dietary lipids can modulate the antioxidant defence system, and an excess of energy and cholesterol has a negative influence on the antioxidant enzymes.

Effect of high-dose intravenous N-acetylcysteine on the concentration of plasma sulfur-containing amino acids

BACKGROUND

The purpose of this study was to determine the adequate loading and maintenance doses of N-acetylcyseteine (NAC) for patients suffering from acute ROS-induced injury.

METHODS

Concentrations of extra cellular NAC, cysteine (Cys), cystine (Cyst2), and methionine (Met) were measured in vitro, at which more than 50% of the intracellular ROS raised by paraquat were suppressed using Swiss 3T3 fibroblasts. An in vivo pharmacokinetic study followed on a healthy subject to determine the proper loading and maintenance doses of reduced NAC following intravenous administration of 25 mg/kg NAC.

RESULTS

In vivo, NAC suppressed ROS in a dose dependant manner. 10 mM of NAC suppressed about 50% of ROS, and was comparable to 10 microM of Cys and Met and 400 microM of Cys2. In vitro, the elimination of half life was achieved at 2.88+/-1.14 h for NAC and at 3.68+/-1.84 h for total NAC. The body clearances were 1.23+/-0.77 L h(-1) kg(-1) and 0.56+/-0.27 L h(-1) kg(-1) and the volumes of distribution were 3.07+/-0.10 L kg(-1) and 3.00+/-0.11 L kg(-1), respectively. The loading and maintenance NAC doses used to reach the target concentration of 10 mM, were 5010 mg. kg(-1) and 2250 mg min(-1) kg(-1), respectively

CONCLUSION

NAC provides an antioxidant effect on ROS produced by paraquat in vivo. However, in vitro, our results showed that the intravenous NAC dose could not be estimated from NAC plasma concentration or its metabolites.