Suppressive effects of breast milk on oxidative DNA damage in very low birthweight infants

BACKGROUND: Human milk contains many kinds of antioxidant and is considered to prevent diseases mediated by oxygen free radicals in very low birthweight (VLBW) infants. AIMS: To examine the antioxidant effects of breast milk in VLBW infants by determining urinary 8-hydroxydeoxyguanosine (8-OHdG) excretion, which is known to be a non-invasive marker for in vivo oxidative DNA damage. METHODS: Urinary 8-OHdG concentrations were measured in 15 breast fed and 14 formula fed VLBW infants at 2, 7, 14, and 28 days of age. RESULTS: Urinary 8-OHdG excretion at 14 and 28 days of age was significantly lower than at 2 and 7 days of age in the breast fed group, and significantly lower than in the formula fed group. CONCLUSION: This is the first direct evidence of the antioxidant action of human milk in VLBW infants.     

Effects of exclusive formula or breast milk feeding on oxidative stress in healthy preterm infants.

BACKGROUND: Compared to formula, breast milk is considered to have superior antioxidant properties and consequently may reduce the occurrence of a number of diseases of prematurity associated with oxidative stress. AIMS: To test whether the antioxidant properties of breast milk in healthy premature infants are different to those of formula milk by comparing vitamin E levels in milk and determining the excretion of malondialdehyde (MDA) in urine. METHODS: Vitamin E was measured in the breast milk of 20 mothers who had given birth prematurely. Urinary MDA was measured in 10 exclusively breast milk fed and 10 exclusively formula fed healthy preterm infants receiving no vitamin supplements. MDA was measured after derivatisation with 2,4-dinitrophenylhydrazine and consecutive HPLC with UV detection. RESULTS: Urinary MDA concentrations were consistently very low (0.074+/-0.033 microM/mM Cr and 0.078+/-0.026 microM/mM Cr in breast and formula fed infants respectively) and not significantly different between healthy breast milk and formula fed infants. Both breast and formula milk contained satisfactory levels (0.3-3.0 mg/100 ml) of vitamin E. CONCLUSION: Antioxidant properties of both breast milk and formulae are sufficient to prevent significant lipid peroxidation in healthy premature infants.     

Oxidative stress and nutrition in the preterm newborn

Oxidative stress occurs when the production of free radicals exceeds the cells' ability to eliminate them. Many events leading to overproduction of free radicals may easily induce oxidative stress in the earliest phases of human life. Given the growing role of oxidative stress in newborn preterm morbidity, one of the goals of modern neonatology is to minimize free radical production and promote the development of adequate antioxidant systems through an adequate nutritional strategy. Appropriate administration of total parenteral solutions and lipid emulsions with light protection can minimize the risk of peroxidation. Providing the baby with amino acid substrates for cellular glutathione synthesis immediately after birth promotes antioxidant defenses at the early stages of life. Breast milk has been found to have many advantages over formula, including the potential to provide antioxidant protection to infants. It is conceivable that these antioxidants in breast milk help to eliminate free radicals in infants. The role of vitamin administration in preterm nutrition has not yet been established. Clinical trials carried out to test the efficacy of antioxidant drugs or vitamins were inconclusive. At present, there are no evidence-based recommendations about the use of nutritional strategies or antioxidant drugs to minimize oxidative stress in the management of preterm infants.     

Milk from mothers of both premature and full-term infants provides better antioxidant protection than does infant formula

We hypothesized that premature (PT) infants' mother's milk may provide antioxidant advantages compared with milk from mothers of full-term (FT) infants, and human milk may provide antioxidant properties not seen in infant formulas. We designed three experiments to test these hypotheses. Experiment 1 assessed resistance to oxidative stress of human milk and formulas designed for FT and PT infants. Experiment 2 determined differences in resistance to oxidative stress between milk from mothers of FT and PT infants, including analysis of catalase activity. Experiment 3 examined factors in human milk that may account for increased resistance to oxidative stress. In experiment 1, we induced physiologic oxidative stress in human milk (n = 5) and formula (n = 2) and measured ascorbate radical using electron paramagnetic resonance. Results indicated the following: 1) during oxidative stress, ascorbate may be spared in human milk compared with formula; 2) ascorbate radical production is more intense in formula compared with human milk, with or without oxidative stress; and 3) oxygen consumption in human milk is less than that in formula, with or without oxidative stress. In experiment 2, milk samples were collected from mothers of PT (n = 28) and FT (n = 17) infants at wk 1, 2, and 12 of lactation. No differences in oxygen consumption after oxidative stress appeared between PT and FT milk. Catalase levels in human milk increased with time. In experiment 3, addition of catalase, superoxide dismutase, and glutathione peroxidase to formulas (n = 4) increased resistance to oxidative stress. Denaturing endogenous enzymes did not decrease the ability of human milk to resist oxidative stress. Ferrous sulfate plus vitamin C added to human milk and formulas fortified with iron increased oxidative stress. Addition of iron chelators to formula reduced oxidative stress. In conclusion, human milk has better antioxidant protection than do formulas, perhaps because of the higher iron content of formulas. Milk from mothers of PT and FT infants has equal resistance to oxidative stress.     

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.     

Effects of exclusive formula or breast milk feeding on oxidative stress in healthy preterm infants

Background

Compared to formula, breast milk is considered to have superior antioxidant properties and consequently may reduce the occurrence of a number of diseases of prematurity associated with oxidative stress.

Aims

To test whether the antioxidant properties of breast milk in healthy premature infants are different to those of formula milk by comparing vitamin E levels in milk and determining the excretion of malondialdehyde (MDA) in urine.

Methods

Vitamin E was measured in the breast milk of 20 mothers who had given birth prematurely. Urinary MDA was measured in 10 exclusively breast milk fed and 10 exclusively formula fed healthy preterm infants receiving no vitamin supplements. MDA was measured after derivatisation with 2,4‐dinitrophenylhydrazine and consecutive HPLC with UV detection.

Results

Urinary MDA concentrations were consistently very low (0.074±0.033 μM/mM Cr and 0.078±0.026 μM/mM Cr in breast and formula fed infants respectively) and not significantly different between healthy breast milk and formula fed infants. Both breast and formula milk contained satisfactory levels (0.3–3.0 mg/100 ml) of vitamin E.

Conclusion

Antioxidant properties of both breast milk and formulae are sufficient to prevent significant lipid peroxidation in healthy premature infants.     

Quantitation of glutathione S transferase-π 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.     

Effects of human milk and spermine on hydrogen peroxide-induced oxidative damage in IEC-6 cells

OBJECTIVE: Oxidative stress is intimately involved in the pathologic processes of serious diseases in the perinatal period. Human milk (HM) contains various bioactive substances, some of which are known as antioxidants, including polyamines such as spermine (SPM). We examined the antioxidative properties of HM and SPM in an intestinal epithelial cell line. METHOD: Confluent Intestinal Epithelial Cells-6 (IEC-6) cells were preincubated with 100-fold dilutions of defatted HM, bovine milk, or three artificial milks for 24 hours, followed by hydrogen peroxide (H2O2) challenge (0.5 mM, 30 min) for oxidative stress. Cells were preincubated with either HM or increasing concentrations (within the range of HM) of SPM for 24 hours followed by an H2O2 challenge (0.25 mM, 30 min). RESULTS: HM-treated cells showed the highest survival rate (50%) compared with no pretreatment (27%), bovine milk-treated (6%), or artificial formula-treated (13-16%) cells. Significantly higher survival rates were observed in the cells treated with HM (44.0%) and in those treated with 0.5, 1, or 5 microM of SPM (12.6, 13.1, or 22.2%, respectively) in comparison with the nontreated cells (7.0%). CONCLUSION: Our results demonstrated that HM and SPM alleviated H2O2-induced oxidative damage in IEC-6 cells, whereas bovine milk and artificial formula did not show any antioxidative capacity. These results suggest that HM acts as an antioxidant in the gastrointestinal tract of infants and that SPM plays an important role in the antioxidative properties of HM.     

The effect of oral alpha-lipoic acid on oxidative stress in adolescents with type 1 diabetes mellitus

Background:  Oxidative stress has been implicated in the pathophysiology of diabetic complications. Alpha-lipoic acid (LA), a potent antioxidant, has been shown to be an effective treatment for diabetic neuropathy when given intravenously. Recently, an oral controlled-release formulation of alpha-lipoic acid (CRLA) was developed, and a pharmacokinetic study demonstrated that CRLA maintained significant plasma levels for 67% longer than a common quick-release formulation.
Objective:  To determine if CRLA is an effective antioxidant in type 1 diabetes mellitus (T1D) by measuring its effects on markers of oxidative damage and total antioxidant status.
Methods:  Forty pubertal and postpubertal adolescents with T1D underwent a double-blind, randomized, placebo-controlled study of CRLA for 3 months. 8-hydroxy-2'-deoxyguanosine, 2-thiobarbituric acid-reactive substances, protein carbonyl, total reactive antioxidant potential, hemoglobin A1c (HbA1c), and spot random urine collected for albumin to creatinine ratio were measured before and after treatment.
Results:  There was no significant change in any measurement of oxidative damage, total antioxidant status, HbA1c, or microalbuminuria prevalence after treatment with either placebo or CRLA.
Conclusion:  In this pilot study, CRLA was not an effective treatment for decreasing oxidative damage in T1D, although efficacy may have been limited by issues with compliance.     

Studies of anti-inflammatory effects of Rooibos tea in rats

Background:  Rooibos tea is known to be caffeine free with abundant flavonoids. Aspalathin and nothofagin, the main flavonoids contained in Rooibos tea, have stronger anti-oxidative activity than other flavonoids.
As oxidative stress can induce inflammation, the anti-inflammatory effects of Rooibos tea were investigated using a rat colitis model.
Methods:  Seven-week-old Wister rats were divided into two groups: one group given Rooibos tea, and one given water. After four weeks of breeding, serum superoxide dismutase (SOD) levels were determined using the Electron Spin Resonance analysis. Urine 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations were also determined as reflections of DNA damage using enzyme-linked immunosorbent assay. Furthermore, rats were administrated dextran sodium sulfate (DSS), which is known to induce colitis in rodents, with or without Rooibos tea to evaluate its anti-inflammatory activity. Clinical symptoms, hemoglobin, serum iron and SOD levels were compared between the groups.
Results:  There were no significant differences in bodyweight gain or laboratory data between the groups. The serum SOD levels were significantly increased, and urine 8-hydroxy-2'-deoxyguanosine levels were significantly decreased in the Rooibos group compared with the controls ( P < 0.05 in each). After DSS administration, the serum SOD levels were significantly higher in the Rooibos group compared to the controls ( P < 0.05). As a result, a decreased hemoglobin level, observed in the control group, was prevented in the Rooibos group after the DSS challenge.
Conclusion:  Rooibos tea may prevent DNA damage and inflammation by its anti-oxidative activity in vivo . As Rooibos tea is free from caffeine, routine intake may be safe and useful in reducing oxidative stress in children.     

Breastfeeding may improve nocturnal sleep and reduce infantile colic: Potential role of breast milk melatonin

Melatonin is secreted during the night in adults but not in infants. It has a hypnotic effect as well as a relaxing effect on the smooth muscle of the gastrointestinal tract. It is plausible that breast milk, which consists of melatonin, may have an effect on improving infants' sleep and reducing infantile colic. Our first goal was to assess the differences in the prevalence and severity of infantile colic and nocturnal sleep between breast-fed infants and supplement-fed infants. The second was to characterize the profile of melatonin secretion in human breast milk compared to artificial formulas. Ninety-four mothers of healthy 2 to 4-month-old infants filled a questionnaire regarding irritability/potential infantile colic and sleep characteristics. For the second part, we measured melatonin levels in breast milk of five women every 2 h during 24 h and in three samples of commonly used artificial formulas. Exclusively breast-fed infants had a significantly lower incidence of colic attacks (p = 0.04), lower severity of irritability attacks (p = 0.03), and a trend for longer nocturnal sleep duration (p = 0.06). Melatonin in human milk showed a clear circadian curve and was unmeasurable in all artificial milks. Conclusions. Exclusive breastfeeding is associated with reduced irritability/colic and a tendency toward longer nocturnal sleep. Breast milk (nocturnal) consists of substantial melatonin levels, whereas artificial formulas do not. We speculate that melatonin which is supplied to the infant via breast milk plays a role in improving sleep and reducing colic in breast-fed infants compared to formula-fed ones.     

Artificial sweetener reduces nociceptive reaction in term newborn infants

BACKGROUND: Sucrose has been shown to have an analgesic effect in preterm and term neonates. Sucrose, however, has a high osmolarity and may have deleterious effects in infants with fructose intolerance. Furthermore, it may favour caries. We therefore investigated the effects of a commercially available artificial sweetener (10 parts cyclamate and 1 part saccharin), glycine (sweet amino acid) or breast milk in reducing reaction to pain as compared with a placebo. SUBJECTS: Eighty healthy term infants, four days old, with normal birth weight. INTERVENTIONS: The infants were randomly assigned to one of four groups: 2 ml sweetener, glycine, expressed breast milk or water were given 2 min before a heel prick for the Guthrie test. The procedure was filmed with a video camera and analysed by two observers who did not know which medication the infant had received. RESULTS: Using a multivariate regression analysis, the following variables had significant correlation with relative crying time and recovery time: behavioural state before the intervention, the pricking nurse, and the type of medication. Relative crying time and recovery time were significantly less in the sweetener group but not in the glycine and the breast milk group. CONCLUSIONS: The artificial sweetener used in our study reduces pain reaction to a heel prick in term neonates, and thus provides an alternative to sucrose. In contrast, glycine tends to increase pain reaction whereas breast milk has no effect.     

Urinary oxidative stress markers in young patients with type 1 diabetes

BACKGROUND: Involvement of oxidative stress in the pathogenesis of diabetic vascular complications has been proposed. However, there are few methods to determine the status of oxidative stress both directly and quantitatively in young patients with type 1 diabetes. METHODS: A total of 27 young patients with type 1 diabetes (mean age +/- SD, 12.6 +/- 4.2 years) with normal renal function and 38 healthy control subjects (13.0 +/- 4.6 years) were investigated. Early morning voiding urine samples were collected. The concentrations of acrolein-lysine adducts, 8-hydroxy-2'-deoxyguanosine (8-OHdG) were determined using competitive enzyme-linked immunosorbent assay, and nitric oxide metabolites were measured using the colorimetric, non-enzymatic assay. RESULTS: Urinary concentrations of 8-OHdG, but not acrolein-lysine adducts and nitric oxide metabolites, were significantly increased in the diabetic group. For diabetic patients, microalbuminuria was significantly correlated with higher concentrations of all three markers. Hemoglobin A(1c) values were significantly correlated with 8-OHdG values. CONCLUSIONS: These findings indicate that increased oxidative stress and the risk of vascular complications may be present at early stages of type 1 diabetes.     

Fecal secretory immunoglobulin A in breast milk versus formula feeding in early infancy

We studied the effects of breast milk feeding versus formula feeding during the first 8 weeks of life on the development of local gastrointestinal humoral immune response by measuring fecal secretory immunoglobulin A (SIgA). Forty-four infants were studied and classified into two groups: breast milk (n = 21) and standard Enfamil without iron (n = 23). The fecal specimens were analyzed at birth and 2, 4, and 8 weeks of age. Radial immune diffusion (RID) technique was used to assay the fecal SIgA during these four ages. Marked SIgA changes were detected in the breast milk-fed group. At birth, no fecal SIgA was detected in either group. At 2, 4, and 8 weeks, significant differences were found between the two groups (p4 less than or equal to 0.001 and p8 less than or equal to 0.001). This phenomenon of enhanced fecal SIgA in breast-fed infants versus standard formula-fed infants is not caused solely by the presence of IgA in breast milk; it represents a stimulatory effect of breast milk on the gastrointestinal humoral immunologic development. The possible active stimulatory role of breast milk on the development of immunologic competence and host defense is discussed. These data suggest an additional advantage of breast milk feeding during early life by the protective role of the earlier and enhanced production of SIgA in the gastrointestinal tract.     

Iron absorption and oxidant stress during erythropoietin therapy in very low birth weight premature infants: a cohort study

Background  

Iron supplementation may be associated with oxidative stress particularly in premature infants. Our purpose was to examine 1) early supplemental iron during treatment with erythropoietin (EPO) and oxidative stress; 2) enhanced iron absorption during EPO in those infants receiving human milk. Therefore, we determined the effect of erythropoietin plus supplemental iron intakes (4 mg/kg/d) on antioxidant status and iron incorporation.     

Effect of human breast milk on biological metabolism in infants

The metabolic changes that occur during the postnatal weaning period appear to be particularly important for future health, and human breast milk is considered to provide the optimal source of nutrition for infants. Our previous studies examined the effect of feeding type on antioxidative properties, glucose and insulin metabolism, the lipid profile, metabolomics, and prostaglandin (PG) metabolism in term and preterm infants. A urinary marker of oxidative DNA damage (8‐hydroxy‐2′‐deoxyguanosine) was significantly lower in breast‐fed term and preterm infants than in formula‐fed infants. Markers of insulin sensitivity were significantly lower and atherosclerotic indices were significantly higher in breast‐fed preterm infants than in mixed‐fed infants at discharge. On urinary metabolomics analysis, choline, choline metabolites, and lactic acid were significantly lower in breast‐fed term infants than in formula‐fed infants. Urinary PGD₂ metabolite level in breast‐fed term infants was also significantly lower than in formula‐fed term infants. This indicates that human breast milk affects biological metabolism in early infancy.     

Increasing breast milk production for premature infants with a relaxation/imagery audiotape

Many women whose premature infants are hospitalized in a newborn intensive care unit choose to express breast milk for their babies. Yet anxiety, fatigue, and emotional stress are powerful inhibitors of lactation. To facilitate the breast-feeding experience, intervention mothers were given a 20-minute audio cassette tape based on relaxation and visual imagery techniques. At a single follow-up expression of milk at the hospital approximately 1 week after enrollment, they expressed 63% more breast milk than a randomized group of control mothers. The fat content of the breast milk in the two groups was not significantly different. Among a small group of mothers whose infants were receiving mechanical ventilation, the increase in milk volume compared with that of control mothers was 121%. Longer-term effects of the relaxation/imagery approach (such as extending the duration of breast-feeding or reducing parental stress after hospital discharge) and the physiologic basis for the increased volume of expressed milk (improved milk production v more efficient milk ejection) are appropriate topics for future research.     

Quantification of L-type fatty acid binding protein in the urine of preterm neonates

We measured urinary excretion of L-type fatty acid binding protein (L-FABP) in preterm neonates on days 1, 5-10, and 25-30 of life. Urinary L-FABP levels (expressed as the ratio to creatinine) in preterm neonates were considerably higher than those of healthy adults. They did not change significantly during the study period. Urinary L-FABP levels showed significant positive correlation with those of urinary N-acetyl-beta-D-glucosaminidase activity on day 1, and with those of 8-hydroxy-2'-deoxyguanosine on days 25-30. These results suggest that L-FABP is expressed in the neonatal kidney. Our results may also point to potential effects of proximal tubular damage and oxidative stress on urinary excretion of L-FABP.     

Implications of growth patterns of breast-fed infants for growth references

Among the principal tenets of pediatric nutrition is the expectation that meeting the requirements for essential nutrients by feeding either artificial formulae or human milk results in indistinguishable physiological outcomes. This expectation has not been met. Were this observation confined to functional outcomes related to constituents of human milk not found in formula (e.g. immunological components, hormones and very-long-chain polyunsaturated fatty acids), differences between breast-fed and artificially fed infants would not be surprising. However, differences in growth between breast- and bottle-fed infants who live under favorable conditions were mostly unexpected. Bottle-fed infants demonstrate accelerated growth patterns compared to infants who are breast fed (1, 2). Similarly, differences between the growth of breast-fed infants and established growth references were not anticipated (2–4).     

Formation of advanced glycosylation end products and oxidative stress in young patients with type 1 diabetes

Increased production of advanced glycosylation end products (AGEs) and augmented oxidative stress may contribute to vascular complications in diabetes. Little is known about the formation and accumulation of AGEs in young patients with type 1 diabetes. The aim of the present study was to investigate whether AGE production and oxidative stress are augmented in young patients with type 1 diabetes at early clinical stages of the disease. Urine samples of 38 patients with type 1 diabetes [mean age (+/-SD), 12.8 +/- 4.5 y; diabetes duration, 5.7 +/- 4.3 y; HbA1c, 8.0 +/- 1.6%; urinary albumin excretion, 12.6 +/- 14.4 mg/g creatinine (Cr)] and those of 60 age-matched healthy control subjects were assayed for AGEs, pentosidine and pyrraline, and markers of oxidative stress, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and acrolein-lysine. Of these four markers, urinary concentrations of pentosidine, 8-OHdG, and acrolein-lysine were significantly higher in the patients with diabetes than in the healthy control subjects. For the patient group, pentosidine correlated significantly with 8-OHdG and acrolein-lysine, and pyrraline correlated significantly with acrolein-lysine. Urinary pentosidine, 8-OHdG, and acrolein-lysine but not pyrraline correlated significantly with urinary albumin excretion. Patients with microalbuminuria (> or =15 mg/g Cr) showed significantly higher levels of all four markers than did normoalbuminuric patients and control subjects. The present study indicates that accumulation of AGEs, whose formation is closely linked to oxidative stress, and resultant endothelial dysfunction may start early in the course of type 1 diabetes. This means that the risk of vascular complications may be present at an early age and that the best possible glycemic control should be emphasized from the diagnosis of diabetes.