Effects of parenteral lipid infusion on DNA damage in very low birth weight infants

Fat emulsion given to very low-birthweight infants increases urinary L-FABP

BACKGROUND

In premature infants, many factors influence the function of renal tubules, such as asphyxia, respiratory disorders, use of high-concentration oxygen, hypotension, and drug treatment. When tubular ischemia and oxidative stress develop due to renal microcirculatory pathology, urinary L-type fatty acid-binding protein (L-FABP) level increases.

METHODS

Urinary L-FABP level was measured over time in very low-birthweight infants (VLBWI), and the effect of fat emulsion on L-FABP level was investigated. Thirty-one VLBWI were divided into two groups with regard to treatment with fat emulsion: the lipid group (n = 20) and the control group (n = 11). Urinary L-FABP was measured before (0-3 days of age), during (7-14 days of age), and after fat emulsion treatment (21-28 days of age) in the two groups.

RESULTS

Median urinary L-FABP level before treatment was 459 ng/mgCr (range, 22.7-5100 ng/mgCr; mean, 1067 ± 1570 ng/mgCr) and 797 ng/mgCr (range, 69-3900 ng/mgCr; mean, 1066 ± 1188 ng/mgCr) in the lipid and control groups, respectively, showing no significant difference. Median urinary L-FABP level was 624 ng/mgCr (range, 50-2050 ng/mgCr; mean ± SD, 799 ± 655 ng/mgCr) and 273 ng/mgCr (range, 31-987 ng/mgCr; mean ± SD, 359 ± 323 ng/mgCr) at 7-14 days of age, respectively, showing that the level was significantly higher in the lipid group. At 21-28 days of age, the median level was 462 ng/mgCr (range, 49-1867 ng/mgCr; mean ± SD, 557 ± 534 ng/mgCr) and 130 ng/mgCr (range, 20-993 ng/mgCr; mean ± SD, 290 ± 329 ng/mgCr), respectively, showing that L-FABP level tended to be higher in the lipid group.

CONCLUSIONS

Fat emulsion treatment induced a significant increase in urinary L-FABP level, suggesting that fat emulsion affected the proximal tubule in VLBWI.

Effects of parenteral soybean oil lipid emulsion on the long-chain polyunsaturated fatty acid profile in very-low-birth-weight infants

Aim

Conventional soybean lipid emulsions contain no docosahexaenoic acid (DHA) or arachidonic acid (AA). We investigated the relationship between blood DHA and AA status in 27 very-low-birth-weight (VLBW) infants with or without parenteral lipid emulsion.

Methods

Sixteen infants received parenteral lipid emulsion, and 11 infants were control group. The fatty acid composition of the erythrocyte membrane was analysed at birth and at 2 weeks of age.

Results

No significant difference in AA levels was observed in the lipid emulsion group between the two time points, whereas the AA levels at 2 weeks were significantly lower than at birth in the control group. The DHA levels in both groups at 2 weeks were significantly lower than at birth, but no group differences were observed at both time points.

Conclusion

The use of parenteral soybean oil lipid emulsions in VLBW infants in the postnatal period may prevent the decline in the AA level but does not appear to influence the DHA level.

Diagnostic and Therapeutic Significance of the Oxidative Stress Parameters in Children

Pharmacotherapy of pediatric diseases represents a major challenge considering that the majority of medicines in everyday practice have not been pediatrically evaluated. The efficacy of therapy depends to a large extent on the knowledge of pathophysiological processes in the children organism at different ages. Therefore, research in that direction is of the utmost importance. An imbalance in the production of free oxygen/nitrogen species and parameters of antioxidative protection is a significant factor in many diseases (e.g. heart failure, pulmonary hypertension, asthma, neonatal sepsis, cancer etc.) in children of different age groups. Reactive oxygen/nitrogen species serve as cell signaling molecules for normal biologic processes. An increase in their generation can cause damages which can disrupt normal physiological cellular processes and eventually cause cell death. This review outlines the previous assessments of oxidative stress parameters in children of different ages for some diseases. Also, the potential diagnostic and therapeutic possibilities for the oxydative stress parameters in children have been considered.

Evaluation of a urinary multi-parameter biomarker set for oxidative stress in children, adolescents and young adults

The involvement of reactive oxygen species (ROS) and oxidative stress in pediatric diseases is an important concern, but oxidative stress status in healthy young subjects and appropriate methods for its measurement remain unclear. This study evaluated a comprehensive set of urinary biomarkers for oxidative stress in healthy children, adolescents and young adults. Results show that urinary excretion of acrolein-lysine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), nitrite/nitrate and pentosidine were highest in the youngest subjects and decreased to constant levels by early adolescence. Urinary acrolein-lysine, 8-OHdG, nitrite/nitrate and pentosidine showed significant inverse correlations with age, but pyrraline did not change significantly with age. No significant differences in biomarkers were apparent between males and females. Younger subjects grow rapidly and sustain immune activation, and are probably exposed to high concentrations of ROS and nitric oxide. Consequently, they are more vulnerable to oxidation of lipids, proteins, DNA and carbohydrates. Normal reported values in this study are a basis for future studies of disease mechanisms involving oxidative stress and for future trials using antioxidant therapies for oxidative stress-related diseases in the pediatric field.

Anti-oxidant enzymes and related elements in term and preterm newborns

BACKGROUND

Although oxidative stress-related diseases mostly affect neonates with extremely low birthweight, healthy preterm newborns might also be at risk of oxidative damages. The aim of the present study was to verify this possibility.

METHODS

Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), erythrocyte glutathione peroxidase (GSHPx) and superoxide dismutase (SOD), plasma and erythrocyte concentrations of selenium, zinc and copper were measured until 100 days of life in 30 preterm infants with mean +/- SD birthweight and gestational age of 1605 +/- 122 g and 34.5 +/- 0.5 weeks. The control group included 30 term infants with birthweight 3123 158 g and gestational age 39.6 0.7 weeks.

RESULTS

Throughout the study period urinary 8-OHdG, taken as a marker of oxidative stress, was significantly higher in the preterm than in the term group. Up until 20 days of life, GSHPx activity was significantly lower in the preterm than in the term infants but this was not associated with any apparent selenium deficiency. Conversely, up until 100 days, preterm infants had significantly reduced SOD levels that appeared to reflect a shortage of the elements needed for this enzyme's activity, notably copper, the plasma concentrations of which were constantly and significantly below the control values.

CONCLUSION

The nutritional status of the elements related to the anti-oxidant enzymes, especially zinc and copper, should be carefully assessed in preterm infants, even if their birthweight is not extremely low.

Parenteral lipid emulsions in paediatrics

PURPOSE OF REVIEW

Lipid emulsions are crucial for providing essential fatty acids and energy in infants and children requiring parenteral nutrition. There is ongoing debate about the optimal composition of lipid emulsions and the optimal timing for introducing lipids to the parenteral nutrition of premature infants in order to enhance the benefits and to minimize the risk of complications.

RECENT FINDINGS

Several studies have investigated the effects of early compared with late administration of lipid emulsions. A meta-analysis demonstrated that early introduction of lipid emulsions does not improve short-term growth or prevent morbidity and mortality in preterm infants. On the other hand, early introduction of lipid emulsions was not shown to increase the risk of complications. A number of studies have investigated the effects of different fatty acid compositions in lipid emulsions on peroxidation. In-vitro findings suggest that lipid peroxidation is related to the polyunsaturated fatty acid content and inversely related to the alpha-tocopherol/polyunsaturated fatty acid ratio of the fat emulsion. The composition of lipid emulsions has also been shown to influence fatty acid metabolism. A mixture of medium-chain and long-chain triglycerides seems to enhance the incorporation of essential fatty acids and long-chain polyunsaturated fatty acids into circulating lipids when compared with an emulsion containing only long-chain triglycerides.

SUMMARY

Although the composition of lipid emulsions has been demonstrated to influence peroxidation and fatty acid metabolism, outcome studies are needed to confirm advantageous effects.

Quantitation of glutathione S transferase-pi in the urine of preterm neonates

BACKGROUND

Glutathione S transferases (GSTs) are widely distributed enzymes found in highly varying amounts in tissues of the human body. The enzyme GST-pi in urine has been used as a marker of renal distal tubular cell damage. The present study was intended to evaluate urinary excretion of GST-pi and its relationship to other renal markers and to the status of oxidative stress in preterm neonates.

METHODS

Levels of urinary GST-pi, N-acetyl-beta-glucosaminidase (a marker of proximal tubular damage), albumin (a marker of glomerular damage) and 8-hydroxy-2'-deoxyguanosine (a marker of oxidative stress) and serum creatinine were measured in preterm neonates at 1 and 4 weeks of age.

RESULTS

The results showed that urinary excretion of GST-pi is increased in preterm neonates compared with reported values for healthy adults. No significant relationship was detected between urinary GST-pi and other markers for renal function. Urinary GST-pi showed significantly positive correlation with urinary 8-hydroxy-2'-deoxyguanosine at 1 and 4 weeks. Sick neonates treated with supplemental oxygen and mechanical ventilation showed significantly higher levels of GST-pi as well as 8-hydroxy-2'-deoxyguanosine than clinically stable neonates did at 4 weeks.

CONCLUSIONS

These results indicate the potential effect of systemic oxidative stress on urinary excretion of GST-pi. Further studies are necessary to explore the effect of oxidative conditions on expression of GST-pi in distal tubules in the human kidney.