[Blood ammonia and transaminases in full term infants suffering from perinatal asphyxia]

AIMS

To find hepatic markers of perinatal asphyxia.

PATIENTS AND METHODS

Variations in blood ammonia during the first week of life and in transaminase in serum during the first 48 hours were analysed in four groups of newly born infants (NBI): Group I or control, in which 65 NBI were included, with suspected unconfirmed infection and no other pathologies; Group II, made up of 15 NBI with loss of foetal well being (LFW) with no posterior neurological clinical features; Group III, consisting of 27 NBI with LFW criteria and mild hypoxic ischemic encephalopathy (HIE); and Group IV, with 25 NBI with LFW criteria and mild HIE according to Amiel s criteria.

RESULTS

The average blood ammonia values in full term infants remain steady during the first week of life (87.66 21.69 mg/dL), as occurs in infants with LFW but without HIE (89.08 24.69 mg/dL) and in those with mild HIE (89.08 20.75 mg/dL). In moderate HIE, the blood ammonia level rises until the third day (108.55 7.04 mg/dL) and then drops back to the initial values (p= 0.0045). When grouped by days, these values show significant differences (p= 0.04), with higher values in Group IV. The NBI with HIE presented higher levels of transaminases, especially of AST (GOT) (p= 0.000001), and this increase is proportional to its gravity. No relation was found between values of blood ammonia and transaminases.

CONCLUSIONS

Both blood ammonia and transaminases can be considered to be perinatal asphyxia markers.

Non protein bound iron as early predictive marker of neonatal brain damage

Of the approximately 130 million births worldwide each year, four million infants will suffer from birth asphyxia and, of these, one million will die and a similar number will develop serious sequelae. Before being able to develop effective interventions, a better understanding of the pathophysiological mechanisms leading to brain injury and an early identification of babies at high risk for brain injury are required. This study tests the predictivity of traditional and new markers of foetal oxidative stress in relation to neurodevelopmental outcome in 384 newborn infants. The results indicate plasma non protein bound iron as the best early predictive marker of neurodevelopmental outcome, with 100% sensitivity and 100% specificity for good neurodevelopmental outcome at 0-1.16 micro mol/l, and for poor neurodevelopmental outcome at values >15.2 micro mol/l. The number of children with values between 1.16 and 15.2 were 195. Common use of this predictive marker in neonatology units will improve the ability of clinicians to identify those newborn babies who will develop neurodisability.

Umbilical cord interleukin-6 levels are elevated in term neonates with perinatal asphyxia

BACKGROUND

A correlation between elevation of pro-inflammatory cytokines and white matter injury or abnormal neurologic outcome has been established in the preterm infant. In the full-term neonate, few studies exist linking elevation of cytokines with encephalopathy and poor neurodevelopmental outcome. Our aims were to investigate if serum interleukin-6 concentrations in delivering mothers and their offspring at birth are associated with perinatal asphyxia, and to examine the relation of interleukin-6 levels to the severity of hypoxic-ischemic encephalopathy and to the neurological outcome.

DESIGN AND METHODS

Serum interleukin-6 levels were measured at birth, 24 and 48 h of life in 50 consecutive term uninfected newborns with perinatal asphyxia and 113 randomly selected healthy term newborns, and at delivery in their mothers.

RESULTS

The median cord interleukin-6 concentrations in the infants who developed hypoxic-ischemic encephalopathy was 376-fold as high as the values in the normal infants (P < 0.0001) and 5.5-fold as high as those in the infants with asphyxia who did not develop hypoxic-ischemic encephalopathy (P < 0.05). There was also a significant relationship between interleukin-6 and the degree of hypoxic-ischemic encephalopathy, and between interleukin-6 and neurodevelopmental outcome at 2 years of age. Regardless of outcome, in the asphyxiated infants the interleukin-6 values were significantly lower at both 24 and 48 h of life than at birth, with a significant decline from 24 to 48 h of life. Among mothers of the asphyxiated neonates, there were no significant differences in interleukin-6 concentrations between those delivering neonates with and without hypoxic-ischemic encephalopathy.

CONCLUSIONS

Measurement of IL-6 concentrations in the umbilical cord of neonates with perinatal asphyxia may be useful to identify early, and in a relatively simple way, those who are most likely to have subsequent brain injury and adverse outcome.

Oxidant injury in neonatal erythrocytes during the perinatal period

It has been known for many decades that oxidative stress leads to oxidation of hemoglobin and damage to the erythrocyte membrane. More recently, the factors involved in denaturating of membrane proteins and lipid peroxidation have been investigated in detail, as well as the mechanism of reactive oxygen species formation in red cells. Oxidative stress depletes adenosine triphosphate (ATP) and adenine nucleotides, whereas adenosine monophosphate (AMP) deaminase seems to depress energy metabolism by blocking the salvage pathway of purine nucleotides. Depletion of ATP and activation of AMP deaminase are related to calcium ion concentrations. Denaturating of membrane proteins generally precedes lipid peroxidation and consequent phagocytosis due to caspase activation. Extensive investigations demonstrated the key role of oxidative stress and iron release in a reactive form causing membrane protein damage via the Fenton reaction and hydroxyl radical production. In the absence of efficient protection by antioxidant factors and other molecules such as flavonoids, oxidative stress is responsible for the release of iron in reactive form, predisposing red cells to hemolysis through the formation of senescence antigen. Other well-known sources of oxidative stress in red cells are free radical production outside the red cell by activated phagocytes, endothelial metabolism, hyperoxia, ischemia-reperfusion and the arachidonic acid cascade.

CONCLUSION

The recent insight into the mechanism of oxidative injury of red cells and evidence of relationships between erythrocyte oxidative stress and hypoxia suggest that increased hemolysis is induced by severe hypoxia and acidosis in the fetus as well as the newborn.

Inflammatory mediators in perinatal asphyxia and infection

AIM

To determine serum levels of interleukin-6 (IL-6), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), soluble intercellular adhesion molecule-1 (sICAM-1) and C-reactive protein (CRP) in asphyxiated neonates and compare these inflammatory factors with those found in neonates with perinatal infection.

METHODS

88 neonates were studied, of whom 36 were asphyxiated, 18 were infected and the remaining 34 were controls. Peripheral blood samples were obtained on the 1st, 3rd and 5th postnatal days.

RESULTS

Cytokines IL-6 and IL-1beta as well as sICAM-1 serum levels did not differ between asphyxiated and infected neonates; however, at most time periods, their values were significantly higher than controls. TNF-alpha was similar in the three groups of neonates. CRP serum values were significantly higher in the infected neonates than in the asphyxiated or control subjects. Among the 54 asphyxiated and infected neonates, 15 were considered as severe cases and 39 as mild. The severe cases, at most time periods, had significantly higher IL-6, IL-1beta and sICAM-1 levels compared with the mild ones. Through receiver operating characteristic curves the cut-off points, sensitivities, and specificities for distinguishing neonates at risk or at high risk for brain damage were established.

CONCLUSION

Similar increases in serum levels of IL-6, IL-1beta and sICAM-1 were found in perinatally asphyxiated and infected neonates. As these increases correlated with the severity of the perinatal insults, neonates at high risk for brain damage might be detected.

[Effect of hyperbaric oxygenation on erythrocyte membrane permeability and erythrocyte sorption ability in newborns with birth hypoxia]

The permeability of erythrocyte membranes (PEM) and sorption ability of erythrocytes (SAE) were studied in 13 newborns with posthypoglycemic disorders of cerebral blood circulation (DCBC) of I-II degrees and in 12 healthy newborns. The hyperbolic oxygenation therapy (HOT) was added to the comprehensive treatment of the newborns with DCBC. It was established that the HOT therapy in the newborns with clinical signs of DCBC-I-II had a different effects. As for the newborns, who suffered from a long-term chronicle hypoxia and from asphyxia in birth, PEM and CAF did not change. The children, who had a short pre-natal hypoxia and/or asphyxia, were noted for a normalization of the PEM and CAF parameters. Finally, the HOT therapy produces, on such children, the disintoxocation and adaptogenic effects through improving the condition of DCBC children.

S100 protein content of umbilical cord blood in healthy newborns in relation to mode of delivery

BACKGROUND

Early detection and quantification of brain damage in neonatal asphyxia is important. In adults, S100 protein in blood is associated with damage to the central nervous system.

OBJECTIVE

To determine whether S100 protein can be detected in arterial and venous cord blood of healthy newborns and to relate S100 protein concentrations in cord blood to mode of delivery.

METHOD

S100 protein levels in umbilical cord blood of 81 healthy infants were determined.

RESULTS

S100 protein was present in arterial (median concentration 1.62 micro g/l) and venous (median concentration 1.36 micro g/l) cord blood. Levels were significantly higher in vaginal births (median arterial concentration 1.72 micro g/l; median venous concentration 1.48 micro g/l) than births by caesarean section (1.51 micro g/l and 1.26 micro g/l respectively).

CONCLUSION

More research is necessary to determine whether S100 protein is a useful marker in neonatal asphyxia.

Neuron-specific enolase levels and neuroimaging in asphyxiated term newborns

The study was designed to investigate the cerebrospinal fluid and serum levels of neuron-specific enolase, along with cranial ultrasonography, magnetic resonance imaging (MRI), and electroencephalography (EEG), for predicting the clinical state and neurologic outcome of 26 asphyxiated term newborns. The babies were graded according to the Sarnat and Sarnat classification. Cerebrospinal fluid neuron-specific enolase levels of the 18 babies in the whole hypoxic-ischemic encephalopathy group were higher than the 8 babies in the "no encephalopathy" group. Cerebrospinal fluid neuron-specific enolase levels of 13 cases in the hypoxic-ischemic encephalopathy grade 2 and 3 groups (high-risk group) were higher than both the no encephalopathy and hypoxic-ischemic encephalopathy grade 1 groups when pooled. Cerebrospinal fluid neuron-specific enolase levels of the 7 newborns in the hypoxic-ischemic encephalopathy grade 3 group were also significantly higher than the 5 in the hypoxic-ischemic encephalopathy grade 1 group. The findings of cranial MRI, EEG, and cerebrospinal fluid neuron-specific enolase levels were correlated with each other and the clinical grade of the patients and also were predictive of the neurologic outcome at 1 year of age. Cerebrospinal fluid neuron-specific enolase levels, cranial MRI, and EEG are predictive of outcome of hypoxic-ischemic brain damage in asphyxiated newborns, and this predictivity would increase with the combination of these diagnostic parameters.

[Changes in the system of antioxidant blood defence in newborns with different pathology]

Blood antioxidant enzymes (superoxide dismutase, catalase, ceruloplasmin) were investigated in gestational ages and diseases. Low activity of blood superoxide dismutase and catalase were observed in premature babies and in newborns after acute and chronic hypoxia. In hemolytic disease the activity of antioxidant enzymes of newborns was significantly higher than in healthy infants. This work demonstrates advantages of haemosorbtion compared to exchange blood transfusion. So the antioxidant activity in blood, decreased after blood transfusion, remained at a high level after haemosorbtion. Any deficiency of antioxidant enzymes in newborns may lead to toxyc oxygen effects. Antioxidants are potential therapeutic agents in the above mentioned conditions.

Serial protein S-100 serum levels in preterm babies with perinatal asphyxia and periventricular white matter lesions

In the last years new diagnostic technologies were developed to assess brain development and to identify early brain injury. Some of them are very attractive methods but invasive, expensive, and time-consuming. The availability of clinically useful serum markers of risk for perinatal brain damage will easily permit the development of rational strategies for prevention of cerebral insults in neonates and more accurate prognostic counseling. In this study, protein S-100 (PS-100), a cytosolic constituent of neuroglial cells, was measured serially, during the neonatal period, in a group of preterm infants suffering perinatal asphyxia. Protein S-100 was measured at 1, 7, and 21 days of life by radioimmunoassay. Cerebral ultrasound confirmed cerebral white matter insult. The results of this study show significantly higher protein S-100 serum levels in asphyxiated preterm babies with periventricular white matter lesions, with a peak at 24 hours of life (5.7 +/- 2.9 microg/L) compared with healthy preterm babies (0.6 +/- 0.3 microg/L) ( p <0.05) and progressively lower values at seven (3.3 +/- 2.4 microg/L) and 21 days (2.2 +/- 1.3 microg/L) of life ( p <0.05). These data suggest that elevated protein S-100 serum levels can be considered an indicator of regional brain damage in preterm infants, allowing noninvasive, superior scrutiny of perinatal asphyxia and potential early preventive strategies.

[Umbilical artery lactate level as a marker of the neonatal clinical condition--preliminary results]

The paper presents a trial to assess efficacy of cord artery blood lactate level measurement in assessing clinical condition of the newborn and prognosing occurrence of neonatal complications. Prospective study in 400 newborns revealed occurrence of significantly higher lactate levels in the newborns with perinatal asphyxia, complicated labours, Apgar score below 7 in the 1st minute of life as well as in those with neonatal complications, compared to the healthy controls. Routine testing of cord artery blood lactate level seems to be the high specific test in diagnosing distress in the newborn and prognosing pathology of the neonatal period.

Decreased expression of L-selectin on peripheral blood polymorphonuclear leukocytes in neonates with severe asphyxia

The expression of adherent leukocyte surface molecules, L-selectin (CD62L), and Mac-1 (CD11b/CD18) in peripheral blood polymorphonuclear leukocytes (PMNs) was studied in 48 neonates and 24 healthy adults using fluorescence flow cytometry. L-selectin expression was decreased significantly in neonates, especially those with severe asphyxia (n = 10) compared with adults. Mac-1 expression was significantly increased in neonates compared with adults, but did not differ between 24 normal neonates, 14 neonates with mild asphyxia, and 10 neonates with severe asphyxia. These results suggest that the magnitude of the decrease in L-selectin expression reflects the severity of asphyxia in neonates.

[Effect of folium ginkgo extract on the erythrocyte immunity function and serum lipid peroxide in asphyxia neonate]

OBJECTIVE

To observe the changes of erythrocyte immunity and serum lipid peroxide in asphyxia neonate, and to study the effect of Folium Ginkgo extract (FGE) on them.

METHODS

Thirty asphyxia neonates were randomly divided into 2 groups, the treated group and the control group, 15 in each group. Erythrocyte C3b receptor rosette rate (E-C3bRR), erythrocyte immune complex rosette rate (E-ICR), blood superoxide dismutase (SOD) activity and serum lipid peroxide (LPO) level were determined at 24 hrs after birth. Conventional treatment was given to both groups and FGE (15 mg/kg.d) was given to the treated group additionally for 7-8 days, then the above-mentioned parameters were re-examined and neonatal behavioral neurological assessment (NBNA) was measured as well.

RESULTS

E-C3bRR and SOD lowered, E-ICR and serum LPO increased in the asphyxia neonate significantly (P < 0.05). After treatment, comparison between the two groups showed that E-C3bRR and SOD were higher, E-ICR and serum LPO were lower in the treated group than those in the control group, and NBNA scoring was obviously higher in the former than that in the latter (all P < 0.05).

CONCLUSION

Decrease of erythrocyte immunity in asphyxia neonate is related to the declined anti-oxidation ability and lipid peroxidase injury. FGE could suppress the free radical production, scavenge free radicals, antagonize the lipid peroxidation injury of cell membrane and up-regulate erythrocyte immunity. It displays the effects of nerve tissue protection and hypoxia-ischemic brain injury alleviation.

Protein kinases activities in erythrocyte membranes of asphyxiated newborns

OBJECTIVES

Perinatal asphyxia represents a major cause of acute brain impairment and mortality in neonates. To develop the effective therapies able to reduce post-asphyxial damages, the understanding of biochemical processes accompanying asphyxia appears to be of the great relevance.

DESIGN AND METHODS

The activities of protein kinases A and C, and tyrosine kinases in erythrocyte membranes of healthy and asphyxiated neonatals were compared. Using monoclonal antibodies the band 3 presence and its phosphotyrosine levels were assayed.

RESULTS

In asphyxiated erythrocyte membranes the activities of PKA and tyrosine kinases increased, whereas the activity of PKC was reduced in relation to healthy newborns. Under asphyxia the band 3 has been overphosphorylated; however, its amount decreased.

CONCLUSION

These findings may provide some evidence for a potential role of asphyxia in disturbance of phosphorylation processes in erythrocytes, as reflected by altered protein kinases activities. The diminished band 3 presence may be partially responsible for the impairment of erythrocyte function.

Association between serum macrophage colony-stimulating factor levels and monocyte and thrombocyte counts in healthy, hypoxic, and septic term neonates

OBJECTIVE

Macrophage colony-stimulating factor (M-CSF) is a hematopoietic growth factor that mainly stimulates the growth, differentiation, and proliferation of cells of the monocyte-macrophage lineage. There are only limited numbers of studies about M-CSF levels in neonates, but high levels of serum M-CSF have been reported in septic and some thrombocytopenic adult patients. In this study, we investigated the serum M-CSF levels in healthy, septic, and hypoxic term neonates on the first day of life and examined the relationship of serum M-CSF levels and circulating monocyte and thrombocyte counts in these newborn infants.

STUDY DESIGN

Three groups were defined in this prospective study: group 1, healthy neonates with no risk factors (n = 40); group 2, neonates who had severe hypoxia (n = 20); and group 3, neonates who fulfilled the criteria for early-onset sepsis (n = 18). Blood samples were collected for complete blood cell count and serum M-CSF levels by peripheral venipuncture from each infant in the first 24 hours after birth before any medical therapy.

RESULTS

The gestational ages and birth weights did not differ significantly between the groups. Serum M-CSF levels of the septic neonates were significantly higher than of both healthy and hypoxic neonates, but did not differ significantly between the healthy and hypoxic neonates. There was no significant correlation between serum M-CSF levels and circulating monocyte counts, but there was a significant inverse correlation between serum M-CSF levels and thrombocyte counts. When this correlation was analyzed according to groups, we determined that this inverse correlation between M-CSF levels and thrombocyte counts was especially significant in the septic neonate group, but not significant in the healthy and hypoxic neonate groups.

CONCLUSIONS

Serum M-CSF levels are significantly higher in neonates with sepsis. High serum M-CSF levels may have a possible role in the pathogenesis of thrombocytopenia in neonates with sepsis.

Plasma cyclic guanosine monophosphate reflecting the severity of persistent pulmonary hypertension of the newborn

The aim of the study was to examine the relationship between the plasma concentration of cyclic guanosine monophosphate (cGMP) and pulmonary pressure and hypoxia defined by oxygenation index (OI) in newborn infants with severe persistent pulmonary hypertension (PPHN) on inhaled nitric oxide (NO). In this prospective study, 18 newborn infants having Doppler ultrasound-diagnosed PPHN and treated with NO were investigated. The ratio of pulmonary artery to systemic artery pressure (PAP/SAP) and OI was assessed before treatment and at 0.5, 1, 12, and 24 h from the beginning of NO. At these time points, plasma concentrations of cGMP could be determined in 11 patients. The association of birth asphyxia as assessed by Apgar 1 min and 5 min and plasma cGMP before the NO treatment was examined. The initial median plasma concentration of cGMP was 37.3 pmol/ml (IQR 13.3-79.6). After the start of NO, cGMP increased significantly within 60 min (p = 0.003) and peaked at 12 h. Initial plasma cGMP was associated with Apgar score (1 and 5 min). OI decreased within 30 min of NO and PAP/SAP within 60 min. Persistent high PAP/SAP after 1 h of NO was associated with low cGMP concentration (r = 0.70, p = 0.02). We conclude that a significant increase in plasma cGMP is already evident after 60 min of NO therapy. This effect is accompanied by changes in oxygenation index and in pulmonary artery pressure. Initial plasma concentrations of cGMP were associated with hypoxia assessed as Apgar score.

Six years of experience with the use of room air for the resuscitation of asphyxiated newly born term infants

In the last 6 years, 830 asphyxiated newly born term infants have been resuscitated with room air (RAR; n = 304) or 100% oxygen (OxR; n = 526) in our hospital. We have studied the time to onset of a regular respiratory pattern, morbidity and mortality, blood gases, reduced glutathione (GSH) and oxidised glutathione (GSSG) and antioxidant enzymes in these infants. No significant differences in the effectiveness of either gas sources or in the final outcome have been found. The RAR group required a shorter time of positive pressure ventilation to attain a spontaneous pattern of respiration. The OxR group showed hyperoxaemia during resuscitation, which was positively correlated with increased GSSG concentrations. Significant oxidative stress was found in the OxR group at 28 days of postnatal life when compared with normal control infants and the RAR group. Oxygen concentrations used during the resuscitation of newly born infants should be strictly monitored.

Red blood cell involvement in fetal/neonatal hypoxia

Free radical release plays an important role in the development of brain injury following hypoxic-ischemic encephalopathy. It causes endothelial cell damage and anomalies in NMDA receptors, synaptosome structure and astrocyte function. Mitochondrial dysfunctions caused by asphyxia, reperfusion after ischemia, arachidonic acid cascade, catecholamine metabolism and phagocyte activation are known sources of reactive oxygen species, particularly the superoxide anion (O2(-)). O2(-) mainly induces peroxidation by the Fenton/Haber Weiss reaction or via iron-oxygen complexes. Since both reactions require reactive heavy metals, non-protein-bound iron (NPBI) is essential for the induction of lipid peroxidation. Experimental studies have demonstrated the neurotoxicity of iron in ischemia-reperfusion. Normal axonal transport of brain iron is also reported to be disrupted in hypoxia-ischemia, leading to a buildup of iron in the white matter. The free iron content of erythrocytes (ICRBC) is considered a marker of oxidative stress. Free iron release is accompanied by the oxidation of membrane proteins and the appearance of senescent antigen, as measured by autologous IgG binding. Our preliminary results suggest a significant positive correlation between plasma free iron and the number of nucleated red cells in cord blood, currently considered a reliable index of lasting intrauterine asphyxia but also possessing a high predictive value for poor neurodevelopmental outcome. The rate of erythropoiesis and the entity of ICRBC are related to the degree of asphyxia and the probability of neurological impairment. Since even an increase in NPBI during asphyxia is related to a poor outcome, iron released by red cells could possibly also contribute to NPBI levels.

Transient hyperinsulinism in an asphyxiated newborn infant with hypoglycemia

We describe a case of transient hyperinsulinism in an asphyxiated newborn infant with hypoglycemia. Although hypoglycemia in birth asphyxiated infants is generally attributed to depletion of glycogen stores, we observed severe hyperinsulinism associated with the hypoglycemia. The hypoglycemia was refractory to high glucose delivery rates (25 mg/kg/min), but responded to a combination of octreotide and diazoxide. At 3 weeks of age, the medications were discontinued and infant was normoglycemic on glucose infusion rates of 5-8 mg/kg/min. Subsequent insulin studies were within normal limits. Transient hyperinsulinism should be considered in asphyxiated infants with protracted hypoglycemia and medications designed to suppress insulin secretion may be useful in refractory cases.

Cord blood endothelin-1 and perinatal asphyxia

Discordant data have been reported on endothelin-1 (ET-1), a potent endothelium-derived vasoconstriction peptide, during the neonatal period, and elevated levels have been found in various neonatal diseases. This study evaluated ET-1 in the cord blood of 74 neonates of different gestational age, birthweight, mode of delivery and 5'-Apgar score.

CONCLUSION

Higher ET-1 levels were found in neonates born by emergency caesarean section, and in newborns with low 5'-Apgar score, suggesting that ET-1 could be a marker of perinatal asphyxia.