Can urinary excretion rate of malondialdehyde, uric acid and protein predict the severity and impending death in perinatal asphyxia?

Free Radicals and Neonatal Brain Injury: From Underlying Pathophysiology to Antioxidant Treatment Perspectives

Free radicals play a role of paramount importance in the development of neonatal brain injury. Depending on the pathophysiological mechanisms underlying free radical overproduction and upon specific neonatal characteristics, such as the GA-dependent maturation of antioxidant defenses and of cerebrovascular autoregulation, different profiles of injury have been identified. The growing evidence on the detrimental effects of free radicals on the brain tissue has led to discover not only potential biomarkers for oxidative damage, but also possible neuroprotective therapeutic approaches targeting oxidative stress. While a more extensive validation of free radical biomarkers is required before considering their use in routine neonatal practice, two important treatments endowed with antioxidant properties, such as therapeutic hypothermia and magnesium sulfate, have become part of the standard of care to reduce the risk of neonatal brain injury, and other promising therapeutic strategies are being tested in clinical trials. The implementation of currently available evidence is crucial to optimize neonatal neuroprotection and to develop individualized diagnostic and therapeutic approaches addressing oxidative brain injury, with the final aim of improving the neurological outcome of this population.

The Urinary Uric Acid / Cr ratio as a marker of morbidity and mortality of preterm infants: a case-control study

BACKGROUND

Perinatal asphyxia is one of the main causes of preterm infant mortality. Some studies have shown that The Urinary Uric Acid / Cr (UUA/Cr) ratio may be used as an additional marker for perinatal asphyxia.This study intend to investigate the relationship of this ratio with outcomes of preterm infants admitted to NICU.

METHODS

This case-control study was carried on 102 preterm newborn infants with gestational age of 30 weeks to 33 weeks and 6 days admitted in the neonatal intensive care unit.The case group, consisted of 51 premature neonates with a history of intubation, cardiopulmonary resuscitation, mechanical ventilation and Nasal continuous positive airway pressure (NCPAP) at birth, were compared with 51 matched neonates. The UUA/Cr ratio was measured in the first 24 h after birth. Complications during hospitalization, duration of hospitalization, and final outcome were evaluated.

RESULTS

The mean level of UUA/Cr ratio in case and control group were 5.4 ± 4.1 and 3.6 9 ± 2.9 respectively and this difference was statistically significant (p = 0.014). The UUA/Cr ratio were significantly higher in females, cesarean section delivery, Apgar score ≥ 8, neonates without any complication and neonates with less than 10 days of hospitalization. However, this ratio has no predictive value for the incidence of complications during hospitalization and long-term hospital stay for infants of the case group.

CONCLUSIONS

The Urinary Uric Acid / Cr ratio in the first 24 h after birth in preterm neonates who underwent intubation, NCPAP or cardiopulmonary resuscitation was higher than healthy neonates.

Does red orange juice supplementation has a protective effect on performance, cardiovascular parameters, muscle damage and oxidative stress markers following the Yo-Yo Intermittent Recovery Test Level-1 under polluted air?

This study aimed to investigate the effect of red orange juice supplementation (ROJS) on performance, cardiovascular parameters, muscle damage and oxidative stress markers of athletes following exercise under polluted air. Eleven soccer players performed a Yo-Yo Intermittent Recovery Test Level-1 in polluted area (PA) and non-polluted area (NPA). Participants are invited to drink 500 ml of red orange or placebo (PLA) juice 2.5 h before the test. Blood samples were collected at rest and 3 min after each session to assess creatine kinase (CK), lactate dehydrogenase, malondialdehyde (MDA) and total antioxidant status. Our results showed that, VO_2max, heart rate and systolic blood pressure post-exercise were significantly altered by pollution with both supplements, but the damage was lowered more with ROJS than PLA. Concerning muscle damage and oxidative stress markers, orange juice supplementation blunted the effect of pollution on CK levels post-exercise (p > 0.05) and decreases significantly (p < 0.05) the MDA levels post-exercise in PA and NPA compared to PLA supplementation. In conclusion, ROJS seemed to be an appropriate strategy to reduce the risk of exposure to pollution especially on muscle damage and oxidative stress markers.

Correlation between increased serum malondialdehyde and spectrum of cranial ultrasonography findings in hypoxic ischemic encephalopathy: could it be used as a predictor of disease severity?

Background

Hypoxic ischemic encephalopathy (HIE) is a major cause of mortality and morbidity in neonates. Malondialdehyde (MDH) is a colorless lipid that can be used as a marker for oxidative stress. Cranial ultrasound sensitivity and specificity in detection of neonatal HIE ought to be further investigated. This study aims to detect whether serum (MDH) can be used as an indicator for HIE severity and to assess the role of cranial ultrasound in diagnosis of HIE neurological disorders, correlating ultrasound findings to MDA levels.

Results

Statistically significant differences were found between the serum MDA levels in patients compared to controls as well as among serum MDA in patients with advancing Sarnat stages (I, II, III) P value < 0.001. Statistically significant levels of serum MDA were found in patients with ischemic US findings compared to those with normal scan; 36.4% of cases with ischemic US findings were diagnosed as Sarnat stage II while 63.6% were diagnosed with stage III with a statistically significant difference (P = 0.016).

Conclusion

Cranial ultrasound can be used for diagnosis of neonatal hypoxic ischemic insults, with lower sensitivity in mild cases and increased sensitivity in severe cases; and when combined with measuring serum MDA levels, it can be used as a diagnostic marker and as a predictor for severity of HIE.

Free radicals and neonatal encephalopathy: mechanisms of injury, biomarkers, and antioxidant treatment perspectives

Neonatal encephalopathy (NE), most commonly a result of the disruption of cerebral oxygen delivery, is the leading cause of neurologic disability in term neonates. Given the key role of free radicals in brain injury development following hypoxia-ischemia-reperfusion, several oxidative biomarkers have been explored in preclinical and clinical models of NE. Among these, antioxidant enzyme activity, uric acid excretion, nitric oxide, malondialdehyde, and non-protein-bound iron have shown promising results as possible predictors of NE severity and outcome. Owing to high costs and technical complexity, however, their routine use in clinical practice is still limited. Several strategies aimed at reducing free radical production or upregulating physiological scavengers have been proposed for NE. Room-air resuscitation has proved to reduce oxidative stress following perinatal asphyxia and is now universally adopted. A number of medications endowed with antioxidant properties, such as melatonin, erythropoietin, allopurinol, or N-acetylcysteine, have also shown potential neuroprotective effects in perinatal asphyxia; nevertheless, further evidence is needed before these antioxidant approaches could be implemented as standard care.

Random urine uric acid to creatinine and prediction of perinatal asphyxia: a meta-analysis

Objective: The purpose of the present review is to evaluate whether urine uric acid to creatinine ratio is increased in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE), as well as to assess its predictive accuracy in the disease. Methods: We used the Medline (1966-2017), Scopus (2004-2017), Clinicaltrials.gov (2008-2017), Embase (1980-2017), Cochrane Central Register of Controlled Trials CENTRAL (1999-2017), and Google Scholar (2004-2017) databases in our primary search along with the reference lists of electronically retrieved full-text papers. The hierarchical summary receiver operating characteristic (HSROC) model was used for the meta-analysis of diagnostic accuracy. Results: Fourteen studies were finally included in the present review, that investigated 1226 neonates. Urinary uric acid to creatinine ratio was significantly higher in neonates with perinatal asphyxia than in healthy controls (mean differences (MD): 1.43 95%CI [1.17, 1.69]). Specifically, the mean difference for Sarnat stage 1 was 0.70 (95%CI [0.28, 1.13]), for stage 2 1.41 (95%CI [0.99, 1.84]), and for stage 3 2.71 (95%CI [2.08, 3.35]). The estimated sensitivity for the summary point was 0.90 (95%CI (0.82-0.95)), the specificity was 0.88 (95%CI (0.73-0.95)) and the diagnostic odds ratio was calculated at 63.62 (95%CI (17.08-236.96)). Conclusions: Urinary uric acid to creatinine ratio is a rapid and an easily detected biomarker that may help physicians identify neonates at risk of developing perinatal asphyxia and HIE. However, large-scale prospective studies are still needed to determine its value in predicting mortality, as well as short- and long-term adverse neurological outcomes.

Serum and Urinary Malondialdehyde (MDA), Uric acid, and Protein as markers of perinatal asphyxia

INTRODUCTION

Perinatal asphyxia (PA) is among the leading causes of neonatal morbidity and death in neonatal intensive care units (NICUs). The aims of this research were to determine the concentrations of malondialdehyde (MDA), urine MDA, uric acid, and protein in the cord blood of neonates with perinatal asphyxia and to determine their relationship with the severity of perinatal asphyxia.

METHODS

This matched case-control study was conducted from October 2012 to March 2013. All of the cases and controls were selected from the Gynecology & Obstetrics Department and the NICUs, at Qous Central Hospital in Qena, Egypt. We allocated 20 full-term neonates who had perinatal asphyxia to the case group. Also, we selected 20 healthy neonates for the control group. The subjects were matched with respect to age and gender. At birth and 48 hours later, measurements were made of MDA in cord blood and urine, and uric acid, protein, and creatinine also were measured in both groups. The data were analyzed by SPSS, version 17, using the independent-samples t-test, ANOVA, Tukey's test, and Spearman's correlation coefficient.

RESULTS

At birth and 48 hr later, the newborns' with PA had significantly higher levels of MDA in the cord blood, mean urinary uric acid/creatinine (UUA:Cr), protein/creatinine (UP:Cr), and MDA/creatinine ratio (UMDA:Cr) than the controls; their PA levels were correlated with the degree of hypoxic-ischemic encephalopathy (HIE). The babies who died due to PA had significantly higher levels of cord blood MDA, and they also had higher UUA:Cr, UP:Cr, and UMDA:Cr ratios than the babies who survived.

CONCLUSION

The concentration of MDA in cord blood can be used as a diagnostic marker of oxidative stress in asphyxiated neonates. The ratios of the urinary excretion rates of uric acid, protein, and MDA to creatinine increased as the severity of perinatal asphyxia and associated brain damage increased.

Urinary Uric Acid/Creatinine Ratio as a Marker of Mortality and Unfavorable Outcome in NICU-Admitted Neonates

Background

The survival of neonates who have been admitted to the NICU, especially premature infants with few mortality and morbidity, is the most important attitude.

Objectives

We presumed whether urinary uric acid/creatinine (UUA/Cr) ratio can be a marker of mortality and adverse outcome in neonates which were admitted to the NICU.

Patients and Methods

All preterm infants admitted to our NICU after birth from March 2014 to April 2015 were enrolled in this prospective cohort study. UUA/Cr was measured during the first day of life. The severity of diseases (indicated by the need for high set-up of mechanical ventilation, complications of prematurity, and duration of stay in the NICU) and neonatal death were considered to be the final unfavorable outcomes. The relationship between the Log-transformation (Ln) urinary uric acid/creatinine ratio and the Apgar score at the first and 5^th minute after birth and the duration of stay were analyzed by using linear regression. Statistical analysis was done by using STATA version 11 (STATA Corp, TX, USA). A P < 0.05 was considered to be statistically significant.

Results

A total of 362 preterm infants with a mean gestational age of 32.7 (± 3.9) weeks were admitted to the NICU, out of whom 64 (17.6%) had severe disease and 43 (11.8%) died. The mean UUA/Cr ratio was significantly higher in the admitted neonates (3.30 ± 1.95 vs. 1.36 ± 0.42. P = 0.0001). There was a negative correlation between the UUA/Cr ratio and the 1-minute Apgar score (r = -0.17, P = 0.006) and the 5-minute Apgar score (r = -0.19, P = 0.003). The 1-minute Apgar scores were negatively correlated with the outcome (OR = 0.68; P < 0.001) and the duration of stay (β = -.28; P < 0.001). There was no significant correlation between 5-minute Apgar scores and the outcome. There was a significant positive correlation between the UUA/Cr ratio and an unfavorable outcome (OR = 1.24; CI %95: 1.06 to 1.43, P = 0.006) and increasing duration of stay (β = 0.17; P = 0.009).

Conclusions

The urinary uric acid/creatinine ratio can be used as a simple, noninvasive parameter of the severity of disease and mortality in NICU-admitted neonates.

Metabolomics applied in neonatology

Over the past two decades, host-response biomarkers have been extensively used by clinicians for a better understanding of normal biological processes, the complexity and severity of illnesses, or pharmacological responses to therapeutic intervention. A myriad of information can be drawn from the gender, age, dietary intake and the disease history of an individual. These biomarkers may be promising for the complete phenotyping of a cell, tissue or an organism. In neonatology, these molecular markers may help in prediction of disease severity and its outcome, thus allowing personalized interventions. In this Review, existing data in the literature on metabolites in plasma, urine and maternal milk that may offer a unique insight into the host's dynamic behavior in different neonatal conditions will be examined.

The role of metabolomics in neonatal and pediatric laboratory medicine

Metabolomics consists of the quantitative analysis of a large number of low molecular mass metabolites involving substrates or products in metabolic pathways existing in all living systems. The analysis of the metabolic profile detectable in a human biological fluid allows to instantly identify changes in the composition of endogenous and exogenous metabolites caused by the interaction between specific physiopathological states, gene expression, and environment. In pediatrics and neonatology, metabolomics offers new encouraging perspectives for the improvement of critically ill patient outcome, for the early recognition of metabolic profiles associated with the development of diseases in the adult life, and for delivery of individualized medicine. In this view, nutrimetabolomics, based on the recognition of specific cluster of metabolites associated with nutrition and pharmacometabolomics, based on the capacity to personalize drug therapy by analyzing metabolic modifications due to therapeutic treatment may open new frontiers in the prevention and in the treatment of pediatric and neonatal diseases. This review summarizes the most relevant results published in the literature on the application of metabolomics in pediatric and neonatal clinical settings. However, there is the urgent need to standardize physiological and preanalytical variables, analytical methods, data processing, and result presentation, before establishing the definitive clinical value of results.

Metabolomics in the developing human being

Metabolomics is based on the detailed analysis of metabolites and represents a unique chemical fingerprint of an organism. This approach allows assessing the dynamic behavior of biologic systems with multiple network interactions among individual components. The field of metabolic profiling has rapidly developed over the last decade, with successful applications in various research areas including toxicology, disease diagnosis and classification, pharmacology, and nutrition. This article provides a comprehensive account of existing data in the literature from animal and clinical studies on the use of metabolomics for improved understanding of medical conditions affecting the neonate and the developing human being.

Urinary metabolomics in newborns and infants

Metabolomics is a new approach based on the systematic study of the full complement of metabolites in a biological sample. This technology consists of two sequential steps: (1) an experimental technique, based on nuclear magnetic resonance (NMR) spectroscopy or mass spectrometry, designed to profile low-molecular-weight compounds, and (2) multivariate data analysis. The metabolomic analysis of biofluids or tissues has been successfully used in the fields of physiology, diagnostics, functional genomics, pharmacology, toxicology, and nutrition. Recent studies have evaluated how physiological variables or pathological conditions can affect metabolomic profiles of different biofluids in pediatric populations. The overall metabolic status of the neonate is little known. If more information on perinatal/neonatal maturational processes and their metabolic background were available, the management of sick or preterm newborns might be improved. Currently, the use of metabolomics in neonatology is still in the pioneering phase. Meaningful diagnostic information and simple, noninvasive collection techniques make urine a particularly suitable biofluid for metabolomic approach in neonatal medicine, although blood has also been investigated. Different fields of neonatology such as postnatal maturation, asphyxia/hypoxia, inborn errors of metabolism, nutrition, nephrouropathies, nephrotoxicity, cardiovascular diseases, and other conditions have been investigated using a metabolomic approach. Together with genomics and proteomics, metabolomics appears to be a promising tool in neonatology for the monitoring of postnatal metabolic maturation, the identification of biomarkers as early predictors of outcome, the diagnosis and monitoring of various diseases, and the "tailored" management of neonatal disorders.

Oxidative stress in perinatal asphyxia in relation to outcome

OBJECTIVE

To study the serum levels of oxidative stress markers - malondialdehyde (MDA) and protein carbonyl in babies with perinatal asphyxia and to correlate their levels with the outcome in terms of mortality and neurodevelopmental sequelae.

METHODS

A group of 40 term AGA (appropriate for gestational age) infants with perinatal asphyxia were selected as cases and same number of healthy babies as controls. Serum levels of oxidative stress markers - malondialdehyde and protein carbonyl were determined in cord blood and at 48 hours of life. Their levels were correlated with the outcome of perinatal asphyxia in terms of mortality and the long term neurological outcome.

RESULTS

MDA and protein carbonyl, in cord blood were significantly higher among cases (5.88+/-1.40 micromol/L and 1.50+/-0.48 nmol/mg of protein respectively) than controls (3.11+/-0.82 micromol/L and 0.83+/-0.19 nmol/mg of protein respectively). Among the cases, MDA and protein carbonyl values at 48 hours of life (7.52 +/- 1.06 micrommol/L and 2.91 +/- 0.62 nmol/mg of protein respectively) were significantly higher than those at birth. MDA at birth and 48 hours was significantly higher among babies who had seizures than those who remained seizure free. These values were also significantly higher in babies who expired as compared to those who survived. Protein carbonyl values though higher in those who had seizures and in those who expired, were not statistically significant from controls. MDA and protein carbonyl at birth and 48 hours were higher in babies with developmental delay but the association was not statistically significant.

CONCLUSIONS

In hypoxic ischemic encephalopathy (HIE), oxidative stress markers MDA and protein carbonyl are high at birth and rise further at 48 hours and the values correlate with the morbidity and mortality. Therefore, determining the serum levels of oxidative stress markers MDA and protein carbonyl will be of benefit in predicting the outcome in perinatal asphyxia.

Idiopathic recurrent calcium urolithiasis (IRCU): variation of fasting urinary protein is a window to pathophysiology or simple consequence of renal stones in situ? A tripartite study in male patients providing insight into oxidative metabolism as possible driving force towards alteration of urine composition, calcium salt crystallization and stone formation

Background

In IRCU it is uncertain whether variation of urinary protein, especially non-albumin protein (NAlb-P), is due to the presence of stones or reflects alteration of oxidative metabolism.

Aims

To validate in a tripartite cross-sectional study of 187 ambulatory male patients, undergoing a standardized laboratory programme, whether stones impact on N-Alb-P or the state of oxidative metabolism interferes with IRCU pathophysiology.

Methods

In part 1 the strata low and high of fasting urinary excretion rate per 2 h of N-Alb-P, malonedialdehyde, hypoxanthine, xanthine, pH and other urine components were compared, and association with renal stones in situ evaluated; in part 2 the co-variation of oxidatively modulated environment, fasting urinary pH, calcium (Ca) salt crystallization risk and the number of patients with stones in situ was examined; in part 3, the nucleation of Ca oxalate and Ca phosphate was tested in undiluted postprandial urine of patients and related to the state of oxidative metabolism.

Results

In part 1, N-Alb-P excretion > 4.3 mg was associated with increase of blood pressure, excretion of total protein, hypoxanthine (a marker of tissue hypoxia), malonedialdehyde (a marker of lipid peroxidation), sodium, magnesium, citrate, uric acid, volume, pH, and increase of renal fractional excretion of both NAlb-P and uric acid; when stones were present, urinary pH was elevated but other parameters were unaffected. Significant predictors of N-Alb-P excretion were malonedialdehyde, fractional N-Alb-P and hypoxanthine. In part 2, urine pH > 6.14 was associated with unchanged blood pressure and plasma vasopressin, increase of blood pH, urinary volume, malonedialde hyde, fractional excretion of N-Alb-P, uric acid, Ca phosphate, but not Ca oxalate, supersaturation; this spectrum was accompanied by decrease of concentration of urinary total and free magnesium, total and complexed citrate, plasma uric acid (in humans the major circulating antioxidant) and insulin; the number of stone-bearing patients was increased. Significant predictors of urine pH were body mass index, plasma insulin and uric acid (negative), and urinary xanthine (positive). In part 3 low plasma uric acid, not high urinary malonedialdehyde or high ratio malonedialdehyde/uric acid was significantly associated with diminished Ca but not oxalate tolerance, with the first nucleating crystal type being mostly Ca phosphate (hydroxyapatite), in the rest Ca oxalate dihydrate; uricemia correlated marginally positively (p = 0.055) with Ca tolerance of urine, stronger with blood pressure and insulin, and negatively with urinary xanthine, fractional N-Alb-P, volume, sodium.

Conclusions

In IRCU 1) not renal stones in situ, but disturbed oxidative metabolism apparently modulates nephron functionality, ending up in higher renal NAlb-P release, urinary volume, sodium and pH of fasting urine; 2) etiologically unknown decline of uricemia may represent antioxidant deficiency and cause a risk of hydroxyapatite crystallization and stone formation in a weakly acidic or alkaline inhibitor-deficient and NAlb-P-rich milieu; 3) several observations, linking oxidative and systemic metabolism, are compatible with Ca stone initiation beyond tubules.