Metabolomic Analyses of Plasma Reveals New Insights into Asphyxia and Resuscitation in Pigs (original) (raw)
Pediatric research, 2016
BackgroundPerinatal hypoxic-ischemic brain damage is a major cause of mortality and morbidity in the neonatal period. Currently, limited ranges of biochemical tests assessing the intensity and duration of hypoxia are ready for clinical use. However, the need to initiate hypothermia therapy early after the clinical suspicion of hypoxic-ischemic encephalopathy requires the availability of early and reliable hypoxia markers. We have sought these biomarkers in an experimental model of hypoxia reoxygenation. Hypoxia and hypotension were induced in newborn piglets following a standardized model and reoxygenation was carried out using room air (RA). An untargeted Liquid Chromatography - Time of Flight Mass Spectrometry (LC-TOFMS) approach was used to assess changes in the metabolomic profile of plasma samples after intense hypoxia and upon reoxygenation. At the end of hypoxia, the plasma metabolome showed an increased plasma concentration of analytes reflecting a metabolic adaptation to pr...
Perinatal asphyxia is attributed to hypoxia and/or ischemia around the time of birth and may lead to multiorgan dysfunction. Aim of this research article is to investigate whether different metabolomic profiles occurred according to oxygen concentration administered at resuscitation. In order to perform the experiment, forty newborn piglets were subjected to normocapnic hypoxia and reoxygenation and were randomly allocated in 4 groups resuscitated with different oxygen concentrations, 18%, 21%, 40%, and 100%, respectively. Urine metabolic profiles at baseline and at hypoxia were analysed by 1 H-NMR spectroscopy and metabolites were also identified by multivariate statistical analysis. Metabolic pathways associations were also built up by ingenuity pathway analysis (IPA). Bioinformatics analysis of metabolites characterized the effect of metabolism in the 4 groups; it showed that the 21% of oxygen is the most "physiological" and appropriate concentration to be used for resuscitation. Our data indicate that resuscitation with 21% of oxygen seems to be optimal in terms of survival, rapidity of resuscitation, and metabolic profile in the present animal model. These findings need to be confirmed with metabolomics in human and, if so, the knowledge of the perinatal asphyxia condition may significantly improve.
Resuscitation with 100% O2 Increases Cerebral Injury in Hypoxemic Piglets
Pediatric Research, 2004
Perinatal asphyxia is a major cause of immediate and postponed brain injury in the newborn. We hypothesized that resuscitation with 100% O 2 compared with ambient air is detrimental to the cerebral tissue. We assessed cerebral injury in newborn piglets that underwent global hypoxia and subsequent resuscitation with 21 or 100% O 2 by extracellular glycerol, matrix metalloproteinase (MMP) expression levels, and oxidative stress. Extracellular glycerol was sampled by cerebral microdialysis. MMP levels were analyzed in cerebral tissue by gelatin zymography, broad matrix degrading capacity, and real-time PCR. Total endogenous antioxidant capacity was measured by the oxygen radical absorbance capacity assay. Extracellular glycerol increased 50% after resuscitation with 100% O 2 compared with 21% O 2 . Total MMP activity was doubled in resuscitated animals at endpoint compared with baseline (p ϭ 0.018), and the MMP-2 activity was significantly increased in piglets that were resuscitated with 21% O 2 (p ϭ 0.003) and 100% O 2 (p ϭ 0.001) compared with baseline. MMP-2 mRNA level was 100% increased in piglets that were resuscitated with 100% O 2 as com-pared with 21% O 2 (p Ͻ 0.05). Oxygen radical absorbance capacity values in piglets that were resuscitated with 100% O 2 were considerably reduced compared with both baseline (p ϭ 0.001) and piglets that were resuscitated with 21% O 2 (p ϭ 0.001). In conclusion, our data show increased MMP-2 activity at both gene and protein levels, accompanied with cerebral leakage of glycerol, presumably triggered by augmented oxidative stress. Our findings suggest that resuscitation of asphyxiated piglets with 100% O 2 is detrimental to the piglet brain compared with resuscitation with 21% O 2 . Abbreviations ECM, extracellular matrix MABP, mean arterial blood pressure MMP, matrix metalloproteinase ORAC, oxygen radical absorbance capacity PaCO 2 , arterial carbon dioxide tension PE, phycoerythrin RFU, relative fluorogenic unit ABSTRACT 783
Acta Paediatrica, 2007
excitatory amino acids and Na þ ,K þ -ATPase activity during resuscitation of severely hypoxic newborn piglets. Acta Paediatr 1998; 87: 889-95. Stockholm. ISSN 0803-5253 We tested the hypothesis that early brain recovery in hypoxic newborn piglets is improved by resuscitating with an O 2 supply close to the minimum level required by the newborn piglet brain. Severely hypoxic 2-5-d-old anaesthetized piglets were randomly divided into three resuscitation groups: hypoxaemic (n ¼ 8), 21% O 2 (n ¼ 8), and 100% O 2 groups (n ¼ 8). The hypoxaemic group was mechanically ventilated with 12-18% O 2 adjusted to achieve a cerebral venous O 2 saturation of 17-23% (baseline; 45 Ϯ 1%, mean Ϯ SEM). During the 2 h resuscitation period, extracellular aspartate and glutamate concentrations in the cerebral striatum were higher during hypoxaemic resuscitation (p ¼ 0:044 and p ¼ 0:055, respectively) than during resuscitation with 21% O 2 or 100% O 2 , suggesting an unfavourable accumulation of potent excitotoxins during hypoxaemic resuscitation. The cell membrane Na þ ,K þ -ATPase activity of cerebral cortical tissue after 2 h resuscitation was similar in the three groups ( p ¼ 0:30). In conclusion, hypoxaemic resuscitation did not normalize early cerebral metabolic recovery as efficiently as resuscitation with 21% O 2 or 100% O 2 . Resuscitation with 21% O 2 was as efficient as resuscitation with 100% O 2 in this newborn piglet hypoxia model. ٖ Asphyxia, hypoxanthine, in vivo microdialysis, oxygen, reoxygenation BA Feet,
Cardiorenal recovery of hypoxic newborn pigs after 18%, 21% and 100% reoxygenation
Intensive Care Medicine, 2008
Objectives We examined the effects of 18%, 21% or 100% oxygen on the recovery of the heart and kidneys in a short-term survival model of neonatal hypoxia–reoxygenation (HR). Design Controlled, block-randomized animal study. Setting University animal research laboratory. Subject Large white piglets (1–3 days, 1.7–2.5 kg). Interventions Piglets received normocapnic hypoxia (15% oxygen) (2 h) and were reoxygenated with 18%, 21% or 100% oxygen (1 h) (n = 7 per group) then 21% oxygen (2 h). Sham-operated pigs (n = 7) had no HR. Measurements and results Seventeen of 21 HR piglets recovered from moderate hypoxemia (mean PaO2 27–33 mmHg and pH 7.20–7.22, associated with tachycardia and hypotension). Systemic arterial pressure, heart rate, left renal arterial flow, oxygen transport, plasma troponin-I and creatinine levels were monitored and recovered with no differences among HR groups over 4 days after resuscitation. The 100% group had increased myocardial oxidative stress (oxidized glutathione levels) and the most cardiac HR-induced injury. There were no differences in renal oxidative stress and HR-induced injury among groups. Early oxygenation at 1 h after resuscitation correlated with the plasma troponin-I level at 6 h (r = −0.51 and 0.64 for SaO2 and systemic oxygen extraction ratio, p < 0.05, respectively) and renal HR-induced injury at 4 days (r = 0.61 for renal oxygen delivery, p < 0.05). Conclusions In hypoxic piglets, 18%, 21% and 100% reoxygenation caused similar systemic and renal hemodynamic and functional recovery. The indicators of oxidative stress and HR injury in myocardial and renal tissues suggest that the reoxygenation with 100% oxygen appears sub-optimal and the use of 18% oxygen offers no further benefit, when compared with 21% oxygen.
Biochemical markers of neonatal hypoxia
2008
Neonatal hypoxia is a clinical condition with detrimental biochemical and clinical outcomes, including production of reactive oxygen and nitrogen species, ATP depletion, developmental abnormalities and growth retardation. Diagnostic approaches for hypoxia are largely based on nonspecific clinical criteria, such as Apgar score, umbilical cord pH and fetal heart-rate monitoring. Since our understanding of the biochemical processes of hypoxia has improved, several biochemical markers have been developed. This article highlights the use of hypoxanthine, xanthine, uric acid, xanthine oxidase, malondialdehyde, nitrotyrosine and lactate as markers of hypoxia in animal models, preterm neonates and full-term neonates
Oxygen resuscitation and oxidative-stress biomarkers in premature infants
Research and Reports in Neonatology, 2014
Background: Resuscitation of premature infants with 100% O 2 may initiate significant oxidant stress during development, predisposing them to bronchopulmonary dysplasia. In the study reported here, we examined the effects of three different oxygen concentrations at resuscitation on oxygen saturations (SpO 2 ) and oxidant stress in premature infants. Study design: Infants ,32 weeks gestational age were randomized to 21%, 40%, or 100% O 2 and resuscitated as per 2005 neonatal resuscitation guidelines. Oxygen groups and SpO 2 were unmasked at 10 minutes of age and FiO 2 adjusted to maintain an SpO 2 of 85%-95% for the next 20 minutes. Blood was collected at 24 hours, 1 week, and 4 weeks for measurement of the oxidative-stress markers, such as a reduced glutathione (GSH) to oxidized glutathione (GSSG) ratio (GSH/GSSG), nitrotyrosine levels, and 8-hydroxydeoxyguanosine (8-OHdG) levels. The study was stopped at 30% enrollment following publication of the 2010 neonatal resuscitation guidelines. Results: We enrolled 18 patients during the study period. SpO 2 increased over time (P,0.0001); however, this increase was not different among the three oxygen groups in the first 10 minutes after birth. FiO 2 was significantly higher in the 100% O 2 group, despite weaning (P,0.02) to maintain target saturations at 30 minutes of age. The GSH/GSSG ratio was significantly lower in the 100% O 2 group at 24 hours than in the other groups (P,0.01). Plasma nitrotyrosine was significantly higher in the 40% and 100% O 2 groups over time (P,0.01). Levels of 8-OHdG were significantly higher at 4 weeks compared with at 24 hours, independent of the oxygen group (P,0.0001). Conclusion: In this study, we defined the natural evolution of SpO 2 in the first 10 minutes of life with exposure to three different concentrations of oxygen. Randomization to higher FiO 2 led to higher total oxygen exposure at resuscitation, and this was significantly correlated with markers of systemic oxidant stress.
Perinatal Asphyxia: A Review from a Metabolomics Perspective
Molecules (Basel, Switzerland), 2015
Perinatal asphyxia is defined as an oxygen deprivation that occurs around the time of birth, and may be caused by several perinatal events. This medical condition affects some four million neonates worldwide per year, causing the death of one million subjects. In most cases, infants successfully recover from hypoxia episodes; however, some patients may develop HIE, leading to permanent neurological conditions or impairment of different organs and systems. Given its multifactor dependency, the timing, severity and outcome of this disease, mainly assessed through Sarnat staging, are of difficult evaluation. Moreover, although the latest newborn resuscitation guideline suggests the use of a 21% oxygen concentration or room air, such an approach is still under debate. Therefore, the pathological mechanism is still not clear and a golden standard treatment has yet to be defined. In this context, metabolomics, a new discipline that has described important perinatal issues over the last ye...
Oxidative stress in asphyxiated term infants resuscitated with 100% oxygen
The Journal of Pediatrics, 2003
T he fetal-to-neonatal transition is characterized by physiologic and metabolic changes that are accompanied by a marked increase in the availability of oxygen to the body. 1 As a consequence, the pro-oxidant status may cause oxidative stress. Indeed, under physiologic conditions, there is a remarkable increase in oxidized glutathione levels in rat liver and erythrocytes from human neonates. Intrapartum asphyxia is characterized by transient periods of hypoxia during the ischemic phase followed by reperfusion. 6 Upon reperfusion and re-oxygenation a flood of oxygen-free radicals are generated by the xanthine oxidase system. The amount of oxygen radicals produced is directly dependent on the oxygen as well as the hypoxanthine and other purine concentrations in the tissue. 7,8 Oxygen-free radical generation causes endothelial cell damage and abnormalities in n-methyl-D-aspartate receptors, synaptosome structure, and astrocyte function, thus contributing to the development of brain injury after a hypoxic-ischemic episode. Guidelines recommend the use of 100% oxygen for the resuscitation of the asphyctic newly born infant. 10 However, the use of room air has proved to be efficient for newborn resuscitation, and no differences regarding mortality or short-term morbidity were detected with the use or room air compared with pure oxygen. 11,12 In addition, the use of pure oxygen for resuscitation in animal experiments increased the arterial partial pressure of oxygen above the physiologic range. 13 Hyperoxemia has been associated with numerous negative side effects, including delayed initiation of spontaneous respiration, increased oxygen consumption, and irregularities in the cerebral circulation. 14 Objective To test the hypothesis that resuscitation of asphyxiated infants with pure oxygen causes hyperoxemia and oxidative stress.
Journal of Neurochemistry, 2002
The present study tests the hypothesis that ventilation with 100% 02 during recovery from asphyxia leads to greater disturbance in brain function, as measured by dopamine metabolism, than does ventilation with 21 % oxygen . This hypothesis was tested using mechanically ventilated, anesthetized newborn piglets as an animal model . Cortical oxygen pressure was measured by the oxygen-dependent quenching of phosphorescence, striatal blood flow by laser Doppler, and the extracellular levels of dopamine and its metabolites by in vivo microdialysis . After establishment of a baseline, both the fraction of inspired oxygen (Fi0 2) and the ventilator rate were reduced in a stepwise fashion every 20 min over a 1-h period . For the subsequent 2-h recovery, the animals were randomized to breathing 21 or 100% oxygen . It was observed that during asphyxia cortical oxygen pressure decreased from 36 to 7 torr, extracellular dopamine increased 8,300%, and dihydroxyphenylacetic acid and homovanillic acid decreased by 65 and 60%, respectively, compared with controls . During reoxygenation after asphyxia, cortical oxygen pressure was significantly higher in the piglets ventilated with 100% oxygen than in those ventilated with 21 % oxygen (19 vs . 11 torr) . During the first hour of reoxygenation, extracellular dopamine levels decreased to -200% of control in the 21 % oxygen group, whereas these levels were still much higher in the 100% oxygen group (-500% of control) . After -2 h of reoxygenation, there was a secondary increase in extracellular dopamine to -750 and -3,000% of baseline for the animals ventilated with 21 and 100%, respectively . It is concluded that although 100% Fi02 after asphyxia increases cortical oxygenation compared with 21 % Fi02, it also results in poorer recovery in dopamine metabolism and higher secondary release of striatal dopamine . The resulting increased extracellular levels of dopamine may exacerbate posthypoxic cerebral injury . Key Words: Hypoxia-Hyperoxia-Dopamine-Brain -Newborn . J. Neurochem. 64, 292-298 (1995) .