Urinary Malondialdehyde Concentrations Research Articles

Circulating and Urinary Concentrations of Malondialdehyde in Aging Humans in Health and Disease: Review and Discussion.

(1) Background: Malondialdehyde (MDA) is a major and stable product of oxidative stress. MDA circulates in the blood and is excreted in the urine in its free and conjugated forms, notably with L-lysine and L-serine. MDA is the most frequently measured biomarker of oxidative stress, namely lipid peroxidation. Oxidative stress is generally assumed to be associated with disease and to increase with age. Here, we review and discuss the literature concerning circulating and excretory MDA as a biomarker of lipid peroxidation in aging subjects with regard to health and disease, such as kidney disease, erectile dysfunction, and COVID-19. (2) Methods: Scientific articles, notably those reporting on circulating (plasma, serum) and urinary MDA, which concern health and disease, and which appeared in PubMed were considered; they formed the basis for evaluating the potential increase in oxidative stress, particularly lipid peroxidation, as humans age. (3) Results and Conclusions: The results reported in the literature thus far are contradictory. The articles considered in the present study are not supportive of the general view that oxidative stress increases with aging. Many functions of several organs, including the filtration efficiency of the kidneys, are physiologically reduced in men and women as they age. This effect is likely to result in the apparent "accumulation" of biomarkers of oxidative stress, concomitantly with the "accumulation" of biomarkers of an organ's function, such as creatinine. How free and conjugated MDA forms are transported in various organs (including the brain) and how they are excreted in the urine via the kidney is not known, and investigating these questions should be the objective of forthcoming studies. The age- and gender-related increase in circulating creatinine might be a useful factor to be taken into consideration when investigating oxidative stress and aging.

Urinary Malondialdehyde (MDA) Concentrations in the General Population-A Systematic Literature Review and Meta-Analysis.

Oxidative stress has been associated with various inflammation-related human diseases. It is defined as an imbalance between the production and elimination of reactive oxygen species (ROS). ROS can oxidize proteins, lipids, and DNA, and some of these oxidized products are excreted in urine, such as malondialdehyde (MDA), which is considered a biomarker for oxidative damage of lipids. To interpret changes of this biomarker as a measure of oxidative species overproduction in humans, a background range for urinary MDA concentration in the general population is needed. We sought to establish urinary MDA concentration ranges for healthy adult populations based on reported values in the available scientific literature. We conducted a systematic review and meta-analysis using the standardized protocol registered in PROSPERO (CRD42020146623). EMBASE, PubMed, Web of Science, and Cochrane library databases were searched from journal inception up to October 2020. We included 35 studies (divided into 47 subgroups for the quantitative analysis). Only studies that measured creatinine-corrected urinary MDA with high-performance liquid chromatography (HPLC) with mass spectrometry (MS), fluorescence detection, or UV photometry were included. The geometric mean (GM) of urinary MDA concentration was 0.10 mg/g creatinine and 95% percentile confidence interval (CI) 0.07–0.12. Age, geographical location but not sex, and smoking status had a significant effect on urinary MDA concentrations. There was a significant increasing trend of urinary MDA concentrations with age. These urinary MDA values should be considered preliminary, as they are based on mostly moderate to some low-quality evidence studies. Although urinary MDA can reliably reflect excessive oxidative stress in a population, the influence of physiological parameters that affect its meaning needs to be addressed as well as harmonizing the chemical analytical methods.

The Association Between Oxidative Stress and Depressive Symptom Scores in Elderly Population: A Repeated Panel Study

ObjectivesPrevious epidemiological studies about oxidative stress and depression are limited by hospital-based case-control design, single-time measurements of oxidative stress biomarkers, and the small number of study participants. Therefore, in this study, we analyzed the association between biomarker of oxidative stress and depressive symptom scores using repeatedly measured panel data from a community-dwelling elderly population.MethodsFrom 2008 to 2010, a total of 478 elderly participants residing in Seoul, Korea, were evaluated three times. Participants underwent the Korean version of the Short Form Generic Depression Scale (SGDS-K) test for screening depression, and urinary malondialdehyde (MDA) levels were measured as an oxidative stress biomarker. We used a generalized estimating equation with a compound symmetry covariance structure to estimate the effects of oxidative stress on depressive symptom scores.ResultsA two-fold increase in urinary MDA concentration was significantly associated with a 33.88% (95% confidence interval [CI], 21.59% to 47.42%) increase in total SGDS-K scores. In subgroup analyses by gender, a two-fold increase in urinary MDA concentration was significantly associated with increased SGDS-K scores in both men and women (men: 30.88%; 95% CI, 10.24% to 55.37%; women: 34.77%; 95% CI, 20.09% to 51.25%). In bivariate analysis after an SGDS-K score ≥8 was defined as depression, the third and the fourth urinary MDA quartiles showed a significantly increased odds ratio(OR) of depression compared to the lowest urinary MDA quartile (third quartile OR, 6.51; 95% CI, 1.77 to 24.00; fourth quartile OR, 7.11; 95% CI, 1.99 to 25.42).ConclusionsOur study suggests a significant association between oxidative stress and depressive symptoms in the elderly population.

Association between changes in exposure to air pollution and biomarkers of oxidative stress in children before and during the Beijing Olympics.

It is not known whether exposure to air pollutants causes systemic oxidative stress in children. We investigated the association between exposure to air pollution and biomarkers of oxidative stress in relation to a governmental air quality intervention implemented during the 2008 Beijing Olympic Games. We studied 36 schoolchildren during 5 time periods before and during the Olympic Games in Beijing (June 2007-September 2008). The oxidative stress biomarkers 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and malondialdehyde were measured in urine samples collected daily during each period. Generalized estimating equations were used to examine the relationship between repeated biomarker measurements and ambient air pollutant levels. During the Olympic intervention period, substantial reductions in air pollution (-19% to -72%), urinary 8-oxodG concentrations (-37.4%; 95% confidence interval: -53.5, -15.7), and urinary malondialdehyde concentrations (-25.3%; 95% confidence interval: -34.3, -15.1) were found. Malondialdehyde and 8-oxodG were significantly associated with concentrations of black carbon, fine particulate matter with an aerodynamic with diameter less than 2.5 μm, sulfur dioxide, nitrogen dioxide, and carbon monoxide. Biomarker changes per each interquartile-range increase in pollutants were largest at lag 0 or lag 1. In a 2-pollutant model, the most robust associations were for black carbon. These findings suggest that exposure to black carbon leads to systemic oxidative stress in children.

Urinary phthalate metabolites among elementary school children of Korea: Sources, risks, and their association with oxidative stress marker

Phthalates have been used in a variety of consumer products and hence frequently been detected in humans. Children are susceptible to endocrine disrupting chemicals such as phthalates, but only limited information is available on the sources of exposure and potential adverse health effects among children. In this study, elementary school students (n=39, aged 9–12years) were recruited in Seoul, and first void urine samples were collected twice in three-day intervals. Then six phthalate metabolites were analyzed by high performance liquid chromatography with triple quadrupole tandem mass spectrometry. In addition, malondialdehyde (MDA) as an oxidative stress marker was measured. A questionnaire was conducted and information on food consumption and the use of plastic packaging or storage materials was gathered. The concentrations of phthalate metabolites varied substantially by sampling time even within the same subject, but all target metabolites were detected in 100% of the samples with the highest geometric mean of 107μg/g-creatinine for mono-n-butyl phthalate (MnBP). Urinary levels of mono-isobutyl phthalate (MiBP), and MnBP among Korean children were 8 and 3 times greater than those reported for US children, but those of monoethyl phthalate (MEP) were about 5 times lower than those of US children. Estimated phthalate intakes were generally in safe range, but in 3–8% of the participating children, the hazard quotients greater than one were noted. Urinary MDA concentrations were significantly associated with several metabolite levels after adjusting covariates in regression model. Consumption of dairy products or meat, and use of a plastic material were significantly associated with the DEHP metabolites or MnBP levels in multivariate model. The results of this study provide evidence of the association between phthalate exposure and oxidative stress especially among the early teenagers, and identified major sources that can be applied to development of management plan for phthalate exposure among children.

Determination of urinary malondialdehyde by isotope dilution LC-MS/MS with automated solid-phase extraction: A cautionary note on derivatization optimization

A highly sensitive quantitative LC-MS/MS method was developed for measuring urinary malondialdehyde (MDA). With the use of an isotope internal standard and online solid-phase extraction, urine samples can be directly analyzed within 10min after 2,4-dinitrophenylhydrazine (DNPH) derivatization. The detection limit was estimated as 0.08pmol. This method was further applied to assess the optimal addition of DNPH for derivatization and to measure urinary MDA in 80 coke oven emission (COE)-exposed and 67 nonexposed workers. Derivatization optimization revealed that to achieve complete derivatization reaction, an excess of DNPH is required (DNPH/MDA molar ratio: 893–8929) for urine samples that is about 100 times higher than that of MDA standard solutions (molar ratio: 10–80). Meanwhile, the mean urinary concentrations of MDA in COE-exposed workers were significantly higher than those in nonexposed workers (0.23±0.17 vs 0.14±0.05μmol/mmol creatinine, P<0.005). Urinary MDA concentrations were also significantly associated with the COE (P<0.005) and smoking exposure (P<0.05). Taken together, this method is capable of routine high-throughput analysis and accurate quantification of MDA and would be useful for assessing the whole-body burden of oxidative stress. Our findings, however, raise the issue that derivatization optimization should be performed before it is put into routine biological analysis.

Diet quality scores and oxidative stress in Korean adults

The purpose of diet-quality indices is to assess and guide individual dietary intake for the promotion of health and prevention of disease, and food based dietary-quality indices need to be applied by using each country's own unique diet. We assessed the relationships between relatively simple dietary quality scores modified for a Korean diet, such as the Recommended Food Score (RFS) and alternate Mediterranean Diet Score (aMDS), and oxidative stress biomarkers in Korean adults. A total of 976 adults were recruited for the Biomarker Monitoring for Environmental Health Study between April and December 2005 in Seoul and Incheon, Korea. RFS and aMDS were calculated by using a food-frequency questionnaire. We used regression analyses to assess the associations between diet quality scores and urinary malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). RFS and aMDS were negatively associated with urinary MDA concentrations (P=0.032 for RFS, P=0.043 for aMDS), but not with 8-OHdG after adjusted for potential covariates. After stratified analyses by sex, negative associations between the both scores and urinary MDA concentrations were not significant in both men and women. There were no significant associations of RFS and aMDS with urinary 8-OHdG concentrations. Higher RFS and aMDS scores were related to lower oxidative stress. Therefore, good quality of diet may be useful in reducing oxidative stress.

Antioxidant-rich spice added to hamburger meat during cooking results in reduced meat, plasma, and urine malondialdehyde concentrations

Emerging science has shown the effect of oxidation products and inflammation on atherogenesis and carcinogenesis. Cooking hamburger meat can promote the formation of malondialdehyde that can be absorbed after ingestion.We studied the effect of an antioxidant spice mixture on malondialdehyde formation while cooking hamburger meat and its effects on plasma and urinary malondialdehyde concentrations.Eleven healthy volunteers consumed 2 kinds of burgers in a randomized order: one burger was seasoned with a spice blend, and one burger was not seasoned with the spice blend. The production of malondialdehyde in burgers and malondialdehyde concentrations in plasma and urine after ingestion were measured by HPLC.Rosmarinic acid from oregano was monitored to assess the effect of cooking on spice antioxidant content. Forty percent (19 mg) of the added rosmarinic acid remained in the spiced burger (SB) after cooking. There was a 71% reduction in the malondialdehyde concentration (mean +/- SD: 0.52 +/- 0.02 micromol/250 g) in the meat of the SBs compared with the malondialdehyde concentration (1.79 +/- 0.17 micromol/250 g) in the meat of the control burgers (CBs). The plasma malondialdehyde concentration increased significantly in the CB group as a change from baseline (P = 0.026). There was a significant time-trend difference (P = 0.013) between the 2 groups. Urinary malondialdehyde concentrations (micromol/g creatinine) decreased by 49% (P = 0.021) in subjects consuming the SBs compared with subjects consuming the CBs.The overall effect of adding the spice mixture to hamburger meat before cooking was a reduction in malondialdehyde concentrations in the meat, plasma, and urine after ingestion. Therefore, cooking hamburgers with a polyphenol-rich spice mixture can significantly decrease the concentration of malondialdehyde, which suggests potential health benefits for atherogenesis and carcinogenesis. This trial was registered at clinical trials.gov as NCT01027052.

Antioxidant-rich spice added to hamburger meat during cooking results in reduced meat, plasma, and urine malondialdehyde concentrations

Background: Emerging science has shown the effect of oxidation products and inflammation on atherogenesis and carcinogenesis. Cooking hamburger meat can promote the formation of malondialdehyde that can be absorbed after ingestion.Objective:We studied the effect of an antioxidant spice mixture on malondialdehyde formation while cooking hamburger meat and its effects on plasma and urinary malondialdehyde concentrations.Design: Eleven healthy volunteers consumed 2 kinds of burgers in a randomized order: one burger was seasoned with a spice blend, and one burger was not seasoned with the spice blend. The production of malondialdehyde in burgers and malondialdehyde concentrations in plasma and urine after ingestion were measured by HPLC.Results:Rosmarinic acid from oregano was monitored to assess the effect of cooking on spice antioxidant content. Forty percent (19 mg) of the added rosmarinic acid remained in the spiced burger (SB) after cooking. There was a 71% reduction in the malondialdehyde concentration (mean ± SD: 0.52 ± 0.02 μmol/250 g) in the meat of the SBs compared with the malondialdehyde concentration (1.79 ± 0.17 μmol/250 g) in the meat of the control burgers (CBs). The plasma malondialdehyde concentration increased significantly in the CB group as a change from baseline (P = 0.026). There was a significant time-trend difference (P = 0.013) between the 2 groups. Urinary malondialdehyde concentrations (μmol/g creatinine) decreased by 49% (P = 0.021) in subjects consuming the SBs compared with subjects consuming the CBs.Conclusions: The overall effect of adding the spice mixture to hamburger meat before cooking was a reduction in malondialdehyde concentrations in the meat, plasma, and urine after ingestion. Therefore, cooking hamburgers with a polyphenol-rich spice mixture can significantly decrease the concentration of malondialdehyde, which suggests potential health benefits for atherogenesis and carcinogenesis. This trial was registered at clinical trials.gov as NCT01027052.

Arsenicosis status and urinary malondialdehyde (MDA) in people exposed to arsenic contaminated-coal in China

The current arsenic exposure condition, arsenicosis prevalence, urinary arsenic and MDA (malondialdehyde) concentrations in people were studied. The study area, a village in Xing Ren County in Guizhou Province, PR China, is a coal-borne arsenicosis endemic area that was identified several decades ago. The residents in Xing Ren have been using coal containing high arsenic levels all their life. Urinary arsenic levels of villagers were 192.2 ± 22 µg/g creatinine ( n = 113) in the coal-borne endemic area (Xing Ren county) and were significantly higher than 63.6 ± 5.9 µg/g creatinine ( n = 30) in a neighbouring control site (a village in Xing Yi county). The urinary MDA concentrations of villagers from the endemic area were also significantly higher compared to those of the control area. There was a strong correlation between age and urinary arsenic and MDA concentrations in the endemic area of Xing Ren; urinary arsenic and MDA levels decreased with age. Fifty out of 113 (44.3%) villagers in the endemic area had arsenicosis symptoms and the prevalence in villagers older than 40 y was 100% in male (92.2% overall). Urinary MDA concentration was significantly higher in people with arsenicosis symptoms in the endemic areas. Oxidative stress (urinary MDA concentration) was strongly related to arsenic exposure but not to the age and smoking habit. Higher urinary arsenic and MDA levels in younger villagers from the endemic area suggest that they are having a higher exposure to coal-borne emitted arsenic because they spend more time indoor. There is an urgent need to develop proper intervention methods in the Guizhou endemic areas in order to reduce the risk to the local communities who are still using arsenic contaminated-coal.

Effects of valsartan therapy on protein glycoxidation

Several lines of evidence suggest that both advanced glycation end products (AGEs) and oxidation processes play key roles in the physiology of aging and age-related pathologies, leading to irreversible proteins modifications in both tissues and the extracellular matrix. Such an accelerated accumulation of these modifications has been reported to be present in several age-related chronic diseases, such as atherosclerosis, diabetes, arthritis, and neurodegenerative diseases. The current literature reveals that the specific inhibition of AGEs may constitute an innovative therapeutic goal. In experimental animals, the use of sartans significantly reduces blood pressure and kidney pentosidine content, improving both histologic renal damage and proteinuria. In this study, 12 subjects who were affected by diabetes mellitus and hypertension were subjected to oral antihypertensive therapy with valsartan (class of sartans) with timed sampling of plasma and urine pentosidine, N ε -(carboxymethyl)lysine (CML), malondialdehyde, and isoprostanes levels, respectively, at baseline and after both 3 and 6 months, with parallel ongoing evaluation of glycemic control and blood pressure levels. Valsartan elicited a good antihypertensive effect with a 30% decrease in plasma pentosidine levels ( P < .05) after 3 months of therapy, followed by a slight increase after 6 months. Urinary pentosidine concentrations exhibited a 40% decrease after 3 months (215 ± 19 vs 129 ± 23 nmol/24 h) and a further significant reduction after 6 months of therapy (105 ± 24 nmol/24 h). Plasma CML levels showed a progressive decrease after 3 months (23.15 ± 3.215 vs 19.88 ± 1.684 μmol/mL) and achieved a further slight reduction after 6 months of therapy (19.48 ± 1.339 μmol/mL); for urinary CML, a statistically significant reduction was gained after the sixth month of therapy (48.51 ± 5.70 vs 30.30 ± 2.77 μmol/24 h after 3 months and 27.02 ± 4.13 μmol/24 h after 6 months; F = 7.62, P < .005). Plasma and urinary concentrations of malondialdehyde were slightly modified by valsartan treatment; the mean levels after both 3 and 6 months did not significantly differ from baseline. Urinary 15-F2t-isoprostanes (2.96 ± 0.45 ng/24 h) levels displayed a progressive decrease after both 3 (2.27 ± 0.31 ng/24 h) and 6 months (1.70 ± 0.23 ng/24 h) with statistical significance achieved only at the end of the study ( P < .05). The present data suggest interesting in vivo antiglycation and antioxidation effects of this angiotensin II receptor antagonist with reductions in plasma and urinary pentosidine, plasma CML, and urinary isoprostanes levels. The present study supports an antagonistic role of valsartan in the production of AGEs precursors through the chelation of transition metals and an antioxidant activity that scavenges reactive oxygen species. This property of valsartan may broaden the scope of newly developed pharmacologic inhibitors of advanced glycoxidation.

Urinary Excretion of Malondialdehyde and 1-Hydroxypyrene in Restaurant Workers

SAB2-O-03 Introduction: Restaurant workers may have the risk for occupational exposure to polycyclic aromatic hydrocarbons (PAHs) in cooking oil fume. Urinary malondialdehyde (MDA) and 1-hydroxypyrene (1-OHP) are biologic markers of oxidative damage and PAHs metabolism, respectively. We attempted to evaluate the relationship between MDA and 1-OHP in urine for restaurant workers in this study. Methods: We studied 314 nonsmoker workers of Chinese-type restaurants who had been employed for at least 1 year in northern Taiwan. All participants were asked to answer a questionnaire that inquired their type of job, lifestyle, and health condition. After subjects completed the questionnaires during their annual physical examinations, a single urine sample was collected. The annual physical examinations were arranged during the work shifts. All workers were asked to wash their hands prior to urine collection to avoid environmental contamination. All urine samples were analyzed for 1-OHP and MDA by high-performance liquid chromatograph. Result: For male kitchen workers, median MDA and 1-OHP concentrations (μmol/mol creatinine) were 287.4 and 2.0, respectively. These levels were significantly higher than those for male banquet workers: 216.4 μmol/mol creatinine (P = 0.024) and 0.4 μmol/mol creatinine (P = 0.01), respectively. There was a significantly positive correlation between individual urinary MDA concentrations and 1-OHP concentrations, after adjusting several potential confounders. Discussion and Conclusions: Kitchen workers may have the high risk for occupational exposure to polycyclic aromatic hydrocarbons in cooking oil fume. We need further studies to confirm this finding.

The Role of N-Acetylcysteine in the Prevention of Contrast-Induced Nephrotoxicity

To determine the role of prophylactic N-acetylcysteine in the prevention of contrast-induced nephrotoxicity. One hundred and sixteen patients undergoing noncoronary angiography, with or without pre-existing renal impairment, were randomly assigned to receive prophylactic oral N-acetylcysteine or no treatment. Serum creatinine (sCr) was measured prior to angiography and 48 hr after the procedure. Urine samples were collected before and after the examination for measurement of malondialdehyde (MDA) concentration. Contrast-induced nephrotoxicity (CIN) was defined as a rise in serum creatinine of 0.5 mg/dl (44 mmol/l) at 48 hr. Complete data were available on 106 patients, 53 of whom had received N-acetylcysteine. There were no significant differences between the two groups in baseline characteristics, type of angiogram, or volume and concentration of contrast used. Three patients (2.8%), all of whom had received N-acetylcysteine, developed CIN. In the N-acetylcysteine group, the mean serum creatinine in patients with renal impairment was 151.0 +/- 44.2 micromol/l prior to the procedure and 155.6 +/- 48.6 micromol/l (p = 0.49) after the procedure. Respective values for those without renal impairment were 79.6 +/- 15.1 micromol/l and 81.2 +/- 20.0 micromol/l (p = 0.65). In the group that had not received N-acetylcysteine, the mean serum creatinine levels before and after the procedure were 150.0 +/- 58.1 and 141.4 +/- 48.0 micromol/l (p = 0.17) in patients with renal impairment and 79.7 +/- 14.2 and 81.4 +/- 15.4 micromol/l (p = 0.34) in those without renal impairment. In both groups, no significant change in urinary MDA concentration was observed. There is no benefit to the prophylactic administration of N-acetylcysteine in patients undergoing peripheral angiography using current contrast media.

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....

Association of Lipid Peroxidation with Antenatal Betamethasone and Oxygen Radical Disorders in Preterm Infants

Introduction: Premature infants are highly susceptible to ‘oxygen radical diseases’ (ORD), including bronchopulmonary dysplasia, intraventricular hemorrhage/white matter injury, retinopathy of prematurity, and necrotizing enterocolitis. The incidence of ORD is reduced following antenatal treatment with betamethasone. Oxidant-mediated injury is characterized at the cellular level by peroxidation of lipid membranes. This results in the generation of malondialdehyde (MDA), which can be quantified indirectly by measurement of thiobarbituric acid-reacting substances (TBARS). There is currently no effective way to quantify the risk for ORD. In this study, we analyzed the correlation of early urinary MDA and TBARS with prenatal betamethasone administration and with the development of ORD. Methods: Preterm infants (<30 weeks gestation, n = 25) born at St. Peter’s University Hospital were enrolled. Urine samples were collected during the first 10 days of life and stored at –70°C for 0–21 days. TBARS were quantified by spectrophotometric assay, and malondialdehyde levels measured by HPLC. Subjects were screened for the subsequent development of ORD. Betamethasone administration was defined as one or more doses ≧24 h prior to delivery. Results: Urinary MDA levels increased on days 2–3 and 5–10 relative to day 1 from birth. Maximal urinary MDA concentrations were significantly higher in the ORD group compared to controls, and there was a trend toward increased urinary TBARS in the presence of ORD. Infants receiving prenatal betamethasone demonstrated higher maximal urinary TBARS values during the first 10 days of life than control infants. The length of sample storage from 0 to 3 weeks at –70°C did not significantly affect TBARS measurements. Conclusions: Elevated urinary MDA measurements in the first 10 days are correlated with the risk for ORD. Urinary TBARS concentrations, which are correlated with MDA measurements, can be quantified rapidly and are stable for short-term storage. Our findings suggest that urinary TBARS may be adaptable as a practical tool for assessing the risk for ORD in neonatal intensive care unit patients, allowing clinicians to optimize the use of preventive strategies. Antenatal betamethasone is associated with increased urinary TBARS in the first 10 days of life, indicating that the protective effects of corticosteroids are not mediated through reductions in oxidant-mediated lipid peroxidation.

Effect of blood transfusion on lipid peroxidation in preterm infants

Objective: To see whether there was a link between blood transfusion and lipid peroxidation as measured by urinary malondialdehyde (MDA) concentration in preterm infants. Methods: Urine samples were collected before...

Urinary malondialdehyde concentration in preterm neonates: is there a relationship to disease entities of neonatal intensive care?

In a retrospective study, urinary malondialdehyde concentration in 45 preterm neonates (25-35 weeks' gestation) during their first month of life was measured by HPLC. Urine was collected on different days of life as a 3-h sample. The frequency of urine collection and measurement varied between one (n = 22) and seven times (n = 8) per child. The study group was divided into three categories according to birth weight: low-birth-weight infants (LBW) (n = 16), very low-birth-weight infants (VLBW) (n = 17) and extremely low-birth-weight infants (ELBW) (n = 12). Urinary malondialdehyde concentration was highest in the ELBW group: 1.15 (0.66, 2.12) mumol/l (median and quartiles) versus 0.58 (0.34, 1.18) mumol/l in the VLBW and 0.60 (0.40, 1.06) mumol/l in the LBW groups (ELBW versus VLBW, p < 0.005; ELBW versus LBW, p < 0.02). In oxygen-treated neonates, significantly higher malondialdehyde values were found compared to those without supplementary oxygen (0.89 (0.48, 1.74) versus 0.58 (0.32, 0.89) mumol/l; p < 0.005). Likewise, a higher malondialdehyde concentration was found in infants requiring mechanical ventilation (intermittent mandatory IMV or high frequency ventilation) compared to those breathing spontaneously (intermittent mandatory ventilation: 0.80 (0.42, 1.66); p > 0.05 and high frequency ventilation: 1.20 (0.83, 2.13); p < 0.001 versus 0.57 (0.33, 0.88) mumol/l). Malondialdehyde concentrations correlated significantly with FiO2 values of the individual patients (r = 0.22; p < 0.02). Comparing urinary malondialdehyde concentrations in infants with and without bronchopulmonary dysplasia, a significantly higher malondialdehyde concentration was found in the former group (0.96 (0.51, 2.07) versus 0.60 (0.32, 0.98) mumol/l; p < 0.005)).(ABSTRACT TRUNCATED AT 250 WORDS)