Changes in serum cytokine and cortisol levels in normothermic and hypothermic term neonates after perinatal asphyxia

Perinatal asphyxia and hypothermic treatment from the endocrine perspective

Introduction

Perinatal asphyxia is one of the three most important causes of neonatal mortality and morbidity. Therapeutic hypothermia represents the standard treatment for infants with moderate-severe perinatal asphyxia, resulting in reduction in the mortality and major neurodevelopmental disability. So far, data in the literature focusing on the endocrine aspects of both asphyxia and hypothermia treatment at birth are scanty, and many aspects are still debated. Aim of this narrative review is to summarize the current knowledge regarding the short- and long-term effects of perinatal asphyxia and of hypothermia treatment on the endocrine system, thus providing suggestions for improving the management of asphyxiated children.

Results

Involvement of the endocrine system (especially glucose and electrolyte disturbances, adrenal hemorrhage, non-thyroidal illness syndrome) can occur in a variable percentage of subjects with perinatal asphyxia, potentially affecting mortality as well as neurological outcome. Hypothermia may also affect endocrine homeostasis, leading to a decreased incidence of hypocalcemia and an increased risk of dilutional hyponatremia and hypercalcemia.

Conclusions

Metabolic abnormalities in the context of perinatal asphyxia are important modifiable factors that may be associated with a worse outcome. Therefore, clinicians should be aware of the possible occurrence of endocrine complication, in order to establish appropriate screening protocols and allow timely treatment.

Effect of Therapeutic Hypothermia Treatment on Acute Phase Reactants

Objective In our study, we aimed to examine the effect of therapeutic hypothermia treatment on C-reactive protein (CRP) and interleukin-6 (IL-6) in infants with hypoxic ischemic encephalopathy (HIE).

Methods The data of the patients with the diagnosis of HIE we followed up in our unit between 2017 and 2018 were analyzed retrospectively. Patients who died during follow-up and patients with proven septicemia at the time of examination were excluded from the study. The routine CRP and IL-6 values ​​of the patients included in the study were compared before and after hypothermia treatment.

Results Therapeutic hypothermia treatment applied for 72 hours was found to cause a statistically significant increase in CRP after treatment when compared with the values ​​measured before treatment (0.6 (0.2–1.9) before and median (P25–75), and after treatment 7.5 (4–18) and median (P25–75) mg/L, p=0.00). While IL-6 was found to be high in the early period due to the effect of hypoxia, it was found to be low after hypothermia treatment (80.5 (40–200) median (P25–75) – 32 (18–50) median (P25–75) pg/ml, p=0.131). While the white blood cell count was high before hypothermia treatment due to hypoxia, it was found to be low after treatment (24600 (19600–30100) median (P25–75) –11300 (8800–14200) median (P25–75)/µL, p=0.001).

Conclusion White blood cells and IL-6 can be found to be high due to hypoxia without infection, and CRP can be found to be high after therapeutic hypothermia treatment without infection. The effect of hypoxia and hypothermia should be considered when evaluating acute phase reactants.

Hypothermia is not therapeutic in a neonatal piglet model of inflammation-sensitized hypoxia-ischemia

BACKGROUND

Perinatal inflammation combined with hypoxia-ischemia (HI) exacerbates injury in the developing brain. Therapeutic hypothermia (HT) is standard care for neonatal encephalopathy; however, its benefit in inflammation-sensitized HI (IS-HI) is unknown.

METHODS

Twelve newborn piglets received a 2 µg/kg bolus and 1 µg/kg/h infusion over 52 h of Escherichia coli lipopolysaccharide (LPS). HI was induced 4 h after LPS bolus. After HI, piglets were randomized to HT (33.5 °C 1-25 h after HI, n = 6) or normothermia (NT, n = 6). Amplitude-integrated electroencephalogram (aEEG) was recorded and magnetic resonance spectroscopy (MRS) was acquired at 24 and 48 h. At 48 h, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive brain cell death, microglial activation/proliferation, astrogliosis, and cleaved caspase-3 (CC3) were quantified. Hematology and plasma cytokines were serially measured.

RESULTS

Two HT piglets died. aEEG recovery, thalamic and white matter MRS lactate/N-acetylaspartate, and TUNEL-positive cell death were similar between groups. HT increased microglial activation in the caudate, but had no other effect on glial activation/proliferation. HT reduced CC3 overall. HT suppressed platelet count and attenuated leukocytosis. Cytokine profile was unchanged by HT.

CONCLUSIONS

We did not observe protection with HT in this piglet IS-HI model based on aEEG, MRS, and immunohistochemistry. Immunosuppressive effects of HT and countering neuroinflammation by LPS may contribute to the observed lack of HT efficacy. Other immunomodulatory strategies may be more effective in IS-HI.

IMPACT

Acute infection/inflammation is known to exacerbate perinatal brain injury and can worsen the outcomes in neonatal encephalopathy. Therapeutic HT is the current standard of care for all infants with NE, but the benefit in infants with coinfection/inflammation is unknown. In a piglet model of inflammation (LPS)-sensitized HI, we observed no evidence of neuroprotection with cooling for 24 h, based on our primary outcome measures: aEEG, MRS Lac/NAA, and histological brain cell death. Additional neuroprotective agents, with beneficial immunomodulatory effects, require exploration in IS-HI models.

Temporal Characterization of Microglia-Associated Pro- and Anti-Inflammatory Genes in a Neonatal Inflammation-Sensitized Hypoxic-Ischemic Brain Injury Model

Hypoxic-ischemic encephalopathy (HIE) mainly affects preterm and term newborns, leading to a high risk of brain damage. Coexisting infection/inflammation and birth asphyxia are key factors associated with intracerebral increase of proinflammatory cytokines linked to HIE. Microglia are key mediators of inflammation during perinatal brain injury, characterized by their phenotypic plasticity, which may facilitate their participation in both the progression and resolution of injury-induced inflammation. The purpose of this study was to investigate the temporal expression of genes associated with pro- and anti-inflammatory cytokines as well as the nucleotide-binding domain, leucine-rich repeat protein (NLRP-3) inflammasome from microglia cells. For this purpose, we used our established neonatal rat model of inflammation-sensitized hypoxic-ischemic (HI) brain injury in seven-day-old rats. We assessed gene expression profiles of 11 cytokines and for NLRP-3 using real-time PCR from sorted CD11b/c microglia of brain samples at different time points (3.5 h after LPS injection and 0, 5, 24, 48, and 72 hours post HI) following different treatments: vehicle, E. coli lipopolysaccharide (LPS), vehicle/HI, and LPS/HI. Our results showed that microglia are early key mediators of the inflammatory response and exacerbate the inflammatory response following HI, polarizing into a predominant proinflammatory M1 phenotype in the early hours post HI. The brains only exposed to HI showed a delay in the expression of proinflammatory cytokines. We also demonstrated that NLRP-3 plays a role in the inflammatory resolution with a high expression after HI insult. The combination of both, a preinfection/inflammation condition and hypoxia-ischemia, resulted in a higher proinflammatory cytokine storm, highlighting the significant contribution of acute inflammation sensitizing prior to a hypoxic insult on the severity of perinatal brain damage.

Necessity of early and continuous monitoring for possible infectious complications in children undergoing therapeutic hypothermia

AIM

Since therapeutic hypothermia (TH) is known for its inhibitory effects on leucocyte migration and cytokine synthesis, our aim was to underline the necessity of early monitoring for potential immunomodulatory risks.

METHODS

Using a 13-year retrospective case-control study at the paediatric intensive care unit (PICU) of the Medical University in Vienna, all newborn infants and children receiving TH were screened and compared with a diagnosis-matched control group undergoing conventional normothermic treatment (NT). TH was accomplished by using a non-invasive cooling device. Target temperature was 32-34°C. Children with evident infections, a medical history of an immunodeficiency or undergoing immunosuppressive therapy, were excluded.

RESULTS

During the observational period, 108 patients were screened, 27 of which underwent TH. Culture-proven infections occurred in 22% of the TH group compared with 4% of the normothermic controls (P = .1). From the second day following PICU admission, median C-reactive protein (CRP) values were higher in the TH group (day two P = .002, day three P = .0002, day six P = .008).

CONCLUSION

Children undergoing TH showed earlier and higher increases in CRP levels when compared to normothermic controls. These data underline the necessity of early and continuous monitoring for possible infectious complications.

Brain damage caused by neonatal hypoxia-ischemia and the effects of hypothermia in severe combined immunodeficient (SCID) mice

Neonatal hypoxic-ischemic encephalopathy (HIE) is a major cause of brain damage in newborns. Although therapeutic hypothermia has been shown to be neuroprotective against neonatal HIE in clinical trials, its effect is not satisfactory. Cell-based therapies have attracted much attention as novel treatments for HIE. Preclinical studies on a variety of human cell transplantation methods have been performed in immunodeficient/immunosuppressed animals, such as severe combined immunodeficient (SCID) mice, which lack functional T and B lymphocytes. The detailed characteristics of neonatal HIE in SCID mice, however, have not been delineated. In preclinical studies, novel therapies for neonatal HIE should be evaluated in combination with hypothermia, which has become a standard treatment for neonatal HIE. However, the effects of hypothermia in SCID mice have not been delineated. In the present study, we compared neonatal hypoxic-ischemic (HI) brain damage in SCID mice and wild-type mice treated with or without hypothermia. Male and female mouse pups were subjected to HI insult induced by unilateral common carotid artery ligation combined with systemic hypoxia on postnatal day 12. In the first 4 h after HI insult, body temperature was maintained at 36 °C for the normothermia groups or 32 °C for the hypothermia groups. The severity of brain damage in SCID mice did not differ from that in wild-type mice based on most evaluations, i.e., cerebral blood flow, hemiparesis, muscle strength, spontaneous activity, cerebral hemispheric volume, neuropathological injury, and serum cytokine levels, although spleen weight, brain weight, leukocyte counts and the levels of some cytokines in the peripheral blood were different between genotypes. The effects of hypothermia in SCID mice were comparable to those in wild-type mice based on most evaluations. Taken together, these findings indicate that SCID mice can be used as an appropriate preclinical model for cell therapies for neonatal HIE.

Intranasal IL-4 Administration Alleviates Functional Deficits of Periventricular Leukomalacia in Neonatal Mice

Background: Periventricular leukomalacia (PVL) is the major form of brain injury in premature infants. Currently, there are no therapies to treat PVL. Several studies suggested that polarization of microglia, a resident macrophage-like immune cell in the central nervous system, plays a vital role in brain injury and recovery. As an important mediator of immunity, interleukin-4 (IL-4) has critical effects on many immune cells, such as astrocytes and microglia. Increasing evidence shows that IL-4 plays a well-established role in attenuating inflammation in neurological disorders. Additionally, as a noninvasive and highly effective method, intranasal drug administration is gaining increasing attention. Therefore, in our study, we hypothesized that intranasal IL-4 administration is a promising strategy for PVL treatment.

Methods: The therapeutic effects of IL-4 on neuroprotection were evaluated using a Control group, Hypoxia group, and Hypoxia + IL-4 treatment group. The PVL mouse model was established by a severe acute hypoxia (SAH) protocol. Exogenous IL-4 was intranasally administered to investigate its neuroprotective effects. A functional study was used to investigate neurological deficits, immunohistochemical technology and Western blotting were used to detect protein levels, and electron microscopy was used to evaluate myelination.

Results: The results suggested that hypoxia stimulated Iba1⁺ microglial activation, downregulated myelin-related gene (NG2, MAG, and MBP) expression, reduced MBP protein levels, and caused neurological deficits. However, the intranasal administration of exogenous IL-4 partially inhibited Iba1+ microglial activation, improved myelination, and alleviated neurological deficits. The mechanistic study showed that IL-4 improved myelination possibly through the IL-4Ra-mediated polarization of microglia from the M1 phenotype to the M2 phenotype.

Conclusion: In summary, our findings demonstrated that the intranasal administration of exogenous IL-4 improves myelination and attenuates functional deficits in a hypoxia-induced PVL model. Intranasal IL-4 administration may be a promising strategy for PVL treatment, for which further mechanistic studies are urgent.

Effects of Inadvertent Perioperative Hypothermia on Metabolic and Inflammatory Mediators

Objective

The aim of the present study was to investigate the effects of perioperative undesirable hypothermia on inflammatory (interleukin (IL)-8, IL-10, IL-18, IL-23 and pentraxin (PTX)-3) and metabolic responses (cortisol and insulin) and recovery time.

Methods

A total of 60 patients between the ages of 18 and 65 years who were in the lumbar stabilisation operation were included in the study. In this prospective, randomised controlled study, two groups were constituted as with warmed (Group N) and not warmed (Group C) patients before and during the operation. Diuresis, blood loss, body temperature and side effects were recorded with IL-8, IL-10, IL-18, IL-23, PTX-3, cortisol and insulin levels.

Results

Perioperative diuresis was significantly higher in Group C. Aldrete score was significantly higher in Group N with less shivering and vomiting in the postoperative period. IL-10, PTX-3 and cortisol levels were found to be significantly higher in Group C in the first postoperative hour. PTX-3 and cortisol were found to be significantly higher in Group C after 24 h of the operation. Insulin was significantly higher in Group N. In 72 h, IL-8 in Group N and cortisol level in Group C were significantly higher.

Conclusion

Positive effects of heating the patients in the perioperative period on haemorrhage, diuresis, complications and recovery time were observed in our study. In addition, maintenance of normothermia appeared to modulate the biomarkers that indicate the inflammatory and metabolic responses.

Fas-ligand and interleukin-6 in the cerebrospinal fluid are early predictors of hypoxic-ischemic encephalopathy and long-term outcomes after birth asphyxia in term infants

BACKGROUND

Cerebral ischemia generates neuroinflammation that can induce neural cell death. This cohort study assessed whether Fas-ligand (FasL) and interleukin (IL)-6 levels in the cerebrospinal fluid (CSF) after hypoxic-ischemic encephalopathy (HIE) can serve as biomarkers of hypoxic brain injury in neonates.

METHODS

Term infants (> 37-week gestational age) who were admitted to the neonatal intensive care unit of Karolinska University Hospital in years 2002 to 2004 with perinatal asphyxia were enrolled prospectively. Control infants without brain pathology underwent lumbar puncture for suspected infection. FasL and IL-6 levels were measured in the CSF, by enzyme-linked immunosorbent assays. All patients underwent neurological assessment at 18 months. HIE was classified as mild, moderate, or severe (HIE I-III). Adverse neurological outcome at 18 months was defined as a mental developmental index < 85, deafness, blindness, cerebral palsy, or seizure disorder.

RESULTS

Of the 44 HIE patients, 14, 16, and 14 had HIE-I, HIE-II, and HIE-III, respectively. HIE-II and HIE-III patients had higher FasL and IL-6 levels than HIE-I patients and the 20 controls (all p < 0.0001). Patients with adverse outcomes had higher FasL and IL-6 levels than patients with normal outcomes and controls (both p < 0.0001). On receiver-operator curve analyses, FasL and IL-6 (alone and together) were highly predictive of HIE grade and outcome (areas under the curve range 0.86-0.94) and showed high sensitivity (66.7-100%). These biomarkers performed better than cord blood pH (areas under the curve: HIE grade = 0.80, adverse outcomes = 0.86).

CONCLUSION

CSF biomarkers FasL and IL-6 predicted severity of encephalopathy and long-term outcomes in post-asphyxiated infants better than a standard biomarker.

Cytokine production pattern of T lymphocytes in neonatal arterial ischemic stroke during the first month of life-a case study

Background

The perinatal period carries the highest risk for stroke in childhood; however, the pathophysiology is poorly understood and preventive, prognostic, and therapeutic strategies are not available. A new pathophysiological model describes the development of neonatal arterial ischemic stroke (NAIS) as the combined result of prenatal inflammation and hypoxic–ischemic insult. Neuroinflammation and a systemic inflammatory response are also important features of NAIS. Identifying key players of the inflammatory system is in the limelight of current research.

Case presentation

We present four NAIS cases, in whom detailed analysis of intracellular and plasma cytokine levels are available from the first month of life. All neonates were admitted with the initial diagnosis of hypoxic ischemic encephalopathy (HIE); however, early MRI examination revealed NAIS. Blood samples were collected between 3 and 6 h of life, at 24 h, 72 h, 1 week, and 1 month of life. Peripheral blood mononuclear cells were assessed with flow cytometry and plasma cytokine levels were measured. Pooled data from the cohort of four NAIS patients were compared to infants with HIE.

At 6 and 72 h of age, the prevalence of IL10+ CD8+ lymphocytes remained lower in NAIS. At 6 h, CD8+ lymphocytes in NAIS produced more IL-17. At 72 h, CD8+ cells produced more IL-6 in severe HIE than in NAIS, but IL-6 production remained elevated in CD8 cells at 1 month in NAIS, while it decreased in HIE. At 1 week, the prevalence of TGF-β + lymphocytes prone to enter the CNS was elevated in NAIS. On the other hand, by 1 month of age, the prevalence of TGF-β + CD4+ lymphocytes decreased in NAIS compared to HIE. At 72 h, we found elevated plasma levels of IL-5, MCP-1, and IL-17 in NAIS. By 1 month, plasma levels of IL-4, IL-12, and IL-17 decreased in NAIS but remained elevated in HIE.

Conclusions

Differences in the cytokine network are present between NAIS and HIE. CD8 lymphocytes appear to shift towards the pro-inflammatory direction in NAIS. The inflammatory response appears to be more pronounced at 72 h in NAIS but decreases faster, reaching lower plasma levels of inflammatory markers at 1 month.

Distinct cytokine patterns may regulate the severity of neonatal asphyxia-an observational study

BACKGROUND

Neuroinflammation and a systemic inflammatory reaction are important features of perinatal asphyxia. Neuroinflammation may have dual aspects being a hindrance, but also a significant help in the recovery of the CNS. We aimed to assess intracellular cytokine levels of T-lymphocytes and plasma cytokine levels in moderate and severe asphyxia in order to identify players of the inflammatory response that may influence patient outcome.

METHODS

We analyzed the data of 28 term neonates requiring moderate systemic hypothermia in a single-center observational study. Blood samples were collected between 3 and 6 h of life, at 24 h, 72 h, 1 week, and 1 month of life. Neonates were divided into a moderate (n = 17) and a severe (n = 11) group based on neuroradiological and amplitude-integrated EEG characteristics. Peripheral blood mononuclear cells were assessed with flow cytometry. Cytokine plasma levels were measured using Bioplex immunoassays. Components of the kynurenine pathway were assessed by high-performance liquid chromatography.

RESULTS

The prevalence and extravasation of IL-1b + CD4 cells were higher in severe than in moderate asphyxia at 6 h. Based on Receiver operator curve analysis, the assessment of the prevalence of CD4+ IL-1β+ and CD4+ IL-1β+ CD49d+ cells at 6 h appears to be able to predict the severity of the insult at an early stage in asphyxia. Intracellular levels of TNF-α in CD4 cells were increased at all time points compared to 6 h in both groups. At 1 month, intracellular levels of TNF-α were higher in the severe group. Plasma IL-6 levels were higher at 1 week in the severe group and decreased by 1 month in the moderate group. Intracellular levels of IL-6 peaked at 24 h in both groups. Intracellular TGF-β levels were increased from 24 h onwards in the moderate group.

CONCLUSIONS

IL-1β and IL-6 appear to play a key role in the early events of the inflammatory response, while TNF-α seems to be responsible for prolonged neuroinflammation, potentially contributing to a worse outcome. The assessment of the prevalence of CD4+ IL-1β+ and CD4+ IL-1β+ CD49d+ cells at 6 h appears to be able to predict the severity of the insult at an early stage in asphyxia.

Serial cytokine alterations and abnormal neuroimaging in newborn infants with encephalopathy

AIM

Inflammatory cytokines may play a role in the final common pathway in the pathogenesis of hypoxic-ischaemic injury in experimental models. We aimed to profile the systemic pro-and anti-inflammatory response over the first week of life in term infants at risk of neonatal encephalopathy.

METHOD

In a tertiary referral university neonatal intensive care unit, serial blood samples were analysed from 41 term infants (requiring resuscitation at birth) in this prospective observational pilot study. Serum levels of 10 pro-and anti-inflammatory cytokines were evaluated including interleukin(IL)-1α, IL-1β, IL-6, IL-8, IL-10, tumour necrosis factor(TNF)-α, interferon (IFN)-γ, vascular endothelial growth factor (VEGF), granulocyte/colony-stimulating factor (G-CSF) and granulocyte macrophage/colony-stimulating factor (GM-CSF).

RESULTS

Infants with neonatal encephalopathy and abnormal neuroimaging (n = 15) had significantly elevated granulocyte macrophage/colony-stimulating factor at 0-24 h and interleukin-8, interleukin-6 and interleukin-10 at 24-48 hour. Tumour necrosis factor-α and vascular endothelial growth factor levels were lower at 72-96 hour (p < 0.05). Significantly elevated levels of interleukin-10 were associated with mortality.

CONCLUSION

Serum cytokine changes and innate immune dysregulation in the first week of life may be indicators of outcome in neonatal encephalopathy but require validation in larger studies.

Perinatal Asphyxia and Erythropoietin and VEGF: Serial Serum and Cerebrospinal Fluid Responses

BACKGROUND

Infants with neonatal encephalopathy (NE) of hypoxic-ischaemic origin are at risk of oxidative and ischaemia-reperfusion injury, which may induce abnormal inflammatory responses involving excessive cytokine production and release in serum and cerebrospinal fluid (CSF). Systemic inflammation is found in infants with NE, and we therefore were interested in cytokines associated with hypoxia, including vascular endothelial growth factor (VEGF) and erythropoietin (Epo).

OBJECTIVE

To investigate the relationship between Epo, VEGF levels, brain injury and outcome in a group of term infants exposed to perinatal asphyxia (PA) compared to controls.

METHODS

Serum and CSF biomarkers associated with hypoxia (VEGF, Epo) were serially measured using multiplex immunoassays over days 1-4 in term infants exposed to PA including infants with NE and controls. Results were compared to severity of encephalopathy, MR brain imaging and mortality.

RESULTS

Ninety-four infants had 247 serum samples collected (n = 12 controls, 82 exposed to PA with 34 CSF samples), and 4 infants died. Controls had significantly lower serum Epo levels on days 1 and 2 compared to those exposed to PA (p = 0.02). Grade II/III NE was significantly associated with elevated day 2 Epo and decreased day 1 VEGF (p < 0.05; day 2 Epo AUC = 0.74, cut-off 10.05 IU/ml). Elevated serum Epo was associated with severely abnormal MRI. Mortality was associated with elevated day 3 Epo and decreased day 1 VEGF. CSF levels were all after hypothermia and were not significantly associated with outcome.

CONCLUSION

Serum Epo and VEGF may be markers of severity of hypoxia-ischaemia and brain injury as they are closely related to hypoxic exposure.

The effects of selective head cooling versus whole-body cooling on some neural and inflammatory biomarkers: a randomized controlled pilot study

Background

Therapeutic hypothermia (TH) has become standard care in newborns with moderate to severe hypoxic ischemic encephalopathy (HIE), and the 2 most commonly used methods are selective head cooling (SHC) and whole body cooling (WBC). This study aimed to determine if the effects of the 2 methods on some neural and inflammatory biomarkers differ.

Materials and methods

This prospective randomized pilot study included newborns delivered after >36 weeks of gestation. SHC or WBC was administered randomly to newborns with moderate to severe HIE that were prescribed TH. The serum interleukin (IL)-1β, IL-6, neuron-specific enolase (NSE), brain-specific creatine kinase (CK-BB), tumor necrosis factor-alpha (TNF-α), and protein S100 levels, the urine S100B level, and the urine lactate/creatinine (L/C) ratio were evaluated 6 and 72 h after birth. The Bayley Scales of Infant and Toddler Development-III was administered at month 12 for assessment of neurodevelopmental findings.

Results

The SHC group included 14 newborns, the WBC group included 10, the mild HIE group included 7, and the control group included 9. All the biomarker levels in the SHC and WBC groups at 6 and 72 h were similar, and all the changes in the biomarker levels between 6 and 72 h were similar in both groups. The serum IL-6 and protein S100 levels at 6 h in the SHC and WBC groups were significantly higher than in the control group. The urine L/C ratio at 6 h in the SHC and WBC groups was significantly higher than in the mild HIE and control groups. The IL-6 level and L/C ratio at 6 and 72 h in the patients that had died or had disability at month 12 were significantly higher than in the patients without disability at month 12.

Conclusion

The effects of SHC and WBC on the biomarkers evaluated did not differ. The urine L/C ratio might be useful for differentiating newborns with moderate and severe HIE from those with mild HIE. Furthermore, the serum IL-6 level and the L/C ratio might be useful for predicting disability and mortality in newborns with HIE.

Neonatal hypoxic ischemic encephalopathy-related biomarkers in serum and cerebrospinal fluid

Neonatal hypoxic ischemic encephalopathy (HIE) is a common disease caused by perinatal asphyxia, a major cause of neonatal death, neurological behavior, and long-term disability. Currently, the diagnosis and prognosis of neonatal HIE are based on nervous system clinical manifestations, imaging and electrophysiological examination. These take time and late diagnosis allows brain injury to occur in newborns, so that infants of many brain injury missed the best treatment time, left with varying degrees of neurological sequelae. The use of biomarkers to monitor brain injury and evaluate neuroprotective effects might allow the early intervention and treatment of neonatal HIE to reduce mortality rates. This study reviewed the mechanism of neonatal hypoxic ischemic encephalopathy in relation to numerous brain-related biomarkers including NSE, S-100β, GFAP, UCH-L1, Tau protein, miRNA, LDH, and CK-BB. In early diagnosis of neonatal HIE, S-100β and activin A seems to be better biomarkers. Biomarkers with the greatest potential to predict long-term neurologic handicap of neonates with HIE are GFAP and UCH-L1 and when combined with other markers or brain imaging can increase the detection rate of HIE. Tau protein is a unique biological component of nervous tissues, and might have value for neonatal HIE diagnosis. Combination of more than two biological markers should be a future research direction.

Minimal systemic hypothermia combined with selective head cooling evaluated in a pig model of hypoxia-ischemia

BACKGROUND

Selective head cooling (SHC) with moderate hypothermia (HT) and whole-body cooling are beneficial following perinatal asphyxia. SHC with systemic normothermia (NT) or minimal HT is under-investigated, could obviate systemic complications of moderate HT, and be applicable to preterm infants. We hypothesized that minimal systemic HT with SHC following hypoxia-ischemia (HI) would be neuroprotective compared with systemic NT.

METHODS

Newborn pigs underwent global HI causing permanent brain injury before being randomized to NT (rectal temperature (Trectal) 38.5 °C) or minimal HT (Trectal 37.0 °C) with SHC (cooling cap and body wrap) for 48 h followed by 24-h NT with 72-h survival.

RESULTS

SHC did not reduce global or regional neuropathology score when correcting for insult severity or compared with a NT group matched for HI severity but increased mortality by 26%. During 48 h, the SHC mean ± SD Trectal was 37.0 ± 0.2 °C, and Tdeep brain and Tsuperficial brain were 35.0 ± 1.1 °C and 31.5 ± 1.6 °C, respectively, with stable Tbrain achieved ≥ 3 h after starting cooling.

CONCLUSION

This is the first study in newborn pigs of minimal systemic HT with SHC for 48 h and a further 24 h of NT following HI. Mortality was increased in the cooled group with no neuroprotection in survivors.

Early predictors of outcome in infants treated with hypothermia for hypoxic-ischaemic encephalopathy

Hypoxic-ischaemic encephalopathy (HIE) is a leading cause of acquired neonatal brain injury. Assessment of the severity of cerebral injury and likely neurological outcome in infants with HIE is important for determining management and prognosis, for counselling parents, and for selection for neuroprotective trials. The condition of the infant at birth, the severity of HIE, neurophysiological tests, including amplitude-integrated electroencephalography (aEEG), biochemical markers, and neuroimaging have been used to assess prognosis and predict long-term outcome. The predictive accuracy of these indicators in the early postnatal period is modest. Neurophysiological assessment seems to be most helpful during the first 24 to 48 hours after birth whilst magnetic resonance imaging (MRI) seems most informative later. Several biochemical markers, including serum S100β and neuron-specific enolase (NSE), are also associated with HIE but their levels depend on the timing of sampling and their prognostic value is uncertain. Comprehensive neurophysiological assessment and neuroimaging may be limited to specialist centres. Therapeutic hypothermia is now standard care in infants with moderate to severe HIE so it is important to examine the influence of hypothermia on the assessment of prognosis in these infants.

Therapeutic hypothermia for neonatal encephalopathy

PURPOSE OF REVIEW

Hypothermia for neonatal encephalopathy is now the standard of care. The purpose of this review is to evaluate recent publications (during the past 18 months) that impact the practice of hypothermia as neuroprotection for neonatal hypoxic-ischemic encephalopathy.

RECENT FINDINGS

The review will examine recent publications that influence clinical care, including committee opinion, meta-analysis, and reports of how this practice has evolved in the clinical arena. Biomarkers of acute injury and outcome will be examined. Research involving the future of hypothermia will be noted.

SUMMARY

The rate of death or disability following hypothermia therapy has been reduced substantially; the challenge is to evaluate whether mortality or disability can be reduced further following combination therapy.

Serum cortisol concentrations during induced hypothermia for perinatal asphyxia are associated with neurological outcome in human infants

Birth asphyxia is a cause of neonatal death or adverse neurological sequelae. Biomarkers can be useful to clinicians in order to optimize intensive care management and communication of prognosis to parents. During perinatal adverse events, increased cortisol secretion is due to hypothalamo-pituitary-adrenal axis activation. We aimed to investigate if cortisol variations during therapeutic hypothermia are associated with neurodevelopmental outcome. We compared 18 cases (neonates with birth asphyxia) with 18 controls (healthy term newborns) and confirmed increased serum cortisol concentrations following the peri-partum adverse event. Among cases, we stratified patients according to neurological outcome at 18 months (group A - good; group B - adverse) and found that after 24 h of therapeutic hypothermia serum cortisol concentration was significantly lower in group A vs group B (28.7 ng/mL vs 344 ng/mL, *p = 0.01). In group B serum, cortisol concentration decreased more gradually during therapeutic hypothermia. We conclude that monitoring serum cortisol concentration during neonatal therapeutic hypothermia can add information to clinical evaluation of neonates with birth asphyxia; cortisol values after the first 24 h of hypothermia can be a biomarker associated with neurodevelopmental outcome at 18 months of age.

Biomarkers for severity of neonatal hypoxic-ischemic encephalopathy and outcomes in newborns receiving hypothermia therapy

OBJECTIVE

To evaluate serum neuronal and inflammatory biomarkers to determine whether measurements of umbilical cords at birth can stratify severity of hypoxic-ischemic encephalopathy (HIE), whether serial measurements differ with hypothermia-rewarming, and whether biomarkers correlate with neurological outcomes.

STUDY DESIGN

This is a prospective cohort of inborn term newborns with varying degrees of HIE by neurological assessment. Neuronal glial fibrillary acidic protein (GFAP), ubiquitin carboxyl-terminal hydrolase L1, and inflammatory cytokines were measured in serum from umbilical artery at 6-24, 48, 72, and 78 hours of age. Neurodevelopmental outcomes (Bayley Scales of Infant and Toddler Development-III scales) were performed at 15-18 months.

RESULTS

Twenty neonates had moderate (n = 17) or severe (n = 3) HIE and received hypothermia; 7 had mild HIE and were not cooled. At birth, serum GFAP and ubiquitin carboxyl-terminal hydrolase L1 increased with the severity of HIE (P < .001), and serial GFAP remained elevated in neonates with moderate to severe HIE. Interleukin (IL)-6, IL-8, and vascular endothelial growth factor were greater at 6-24 hours in moderate to severe vs mild HIE (P < .05). The serial values were unaffected by hypothermia-rewarming. Elevated GFAP, IL-1, IL-6, IL-8, tumor necrosis factor, interferon, and vascular endothelial growth factor at 6-24 hours were associated with abnormal neurological outcomes.

CONCLUSIONS

The severity of the hypoxic-ischemic injury can be stratified at birth because elevated neuronal biomarkers in cord serum correlated with severity of HIE and outcomes.

PGE-metabolite levels in CSF correlate to HIE score and outcome after perinatal asphyxia

AIM

Acute anoxic exposure rapidly increases prostaglandin E2 (PGE2 ) production and release in neonatal mice brains. We hypothesize that PGE2 is released in human cerebrospinal fluid (CSF) during perinatal asphyxia and that it might be used as a biomarker for perinatal asphyxia.

METHODS

In full-term infants with lumbar puncture performed within 72 h of birth (n = 35), CSF was analysed for prostaglandin E2 metabolite (PGEM) using an enzyme immunoassay. Term infants with suspected but unverified infections were used as controls (n = 11). Hypoxic-ischaemic encephalopathy (HIE) was classified as mild, moderate or severe (HIE I-III). Neurological assessment of surviving patients was performed at 18 months of age.

RESULTS

Prostaglandin E2 metabolite levels correlated to a low Apgar score at 5 min (p < 0.01) and 10 min (p < 0.01), a low pH (p < 0.001) and HIE score (p < 0.05). The HIE-III cases (n = 7) had significantly higher PGEM levels compared with both controls and the HIE-I group (n = 8). Irrespective of HIE grade, patients with adverse or fatal outcome had higher PGEM values compared with controls and asphyxiated infants with normal outcome (p < 0.05).

CONCLUSIONS

PGE2 is released during anoxic events in newborn infants, and PGEM may be useful as a biomarker for estimating degree of insult and predicting long-term outcome after perinatal asphyxia.