Temporal Trends in the Severity and Mortality of Neonatal Hypoxic-Ischemic Encephalopathy in the Era of Hypothermia

INTRODUCTION

There is a paucity of studies examining temporal trends in the incidence and mortality of moderate-to-severe hypoxic-ischemic encephalopathy (HIE) during the last decade of therapeutic hypothermia (TH).

METHODS

Multicenter cross-sectional study of all infants ≥35 weeks gestational age diagnosed with moderate-to-severe HIE within 6 h of birth in an extensive region of Spain between 2011 and 2019, in order to detect trend changes over time in the (1) annual incidence, (2) severity of neurological and systemic organ involvement, and (3) neonatal death from HIE.

RESULTS

Annual incidence rate of moderate-to-severe HIE was 0.84 (95% confidence interval [CI] 0.7-0.97) per 1,000 births, without trend changes over time (p = 0.8), although the proportion of severe HIE infants showed an average annual decline of 0.86 points (95% CI 0.75-0.98). There were 102 (70%) infants diagnosed with moderate HIE and 44 (30%) with severe HIE. TH was offered to 139/146 (95%) infants. Infants with clinical and/or electrical seizures showed a decreasing trend from 56 to 28% (p = 0.006). Mortality showed a nonstatistically significant decline (p = 0.4), and the severity of systemic damage showed no changes (p = 0.3). Obstetric characteristics remained unchanged, while higher perinatal pH values (p = 0.03) and Apgar scores (p = 0.05), and less need for resuscitation (p = 0.07), were found over time.

CONCLUSION

The annual incidence of moderate-to-severe HIE has stabilized at around 1 per 1,000 births, with a temporal trend toward a decrease in severe HIE infants and a slight decline of mortality. No association was found between temporal trends and changes in perinatal/obstetric characteristics over time.

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.

Sulforaphane Protects Piglet Brains from Neonatal Hypoxic-Ischemic Injury

The striatal, primary sensorimotor cortical, and thalamic neurons are highly vulnerable to hypoxia-ischemia (HI) in term newborns. In a piglet model of HI that exhibits similar selective regional vulnerability, we tested the hypothesis that early treatment with sulforaphane, an activator of the Nrf2 transcription factor, protects vulnerable neurons from HI injury. Anesthetized piglets (aged 3-7 days) were subjected to 45 min of hypoxia and 7 min of airway occlusion. At 15 min after resuscitation, the piglets received intravenous vehicle or sulforaphane. At 4 days of recovery, the density of viable neurons in the putamen of vehicle-treated piglets was 31 ± 34% (±SD) that of sham-operated controls. Treatment with sulforaphane significantly increased viability to 77 ± 31%. In the sensorimotor cortex, neuronal viability was also increased; it was 59 ± 35% in the vehicle-treated and 89 ± 15% in the sulforaphane-treated animals. Treatment with sulforaphane increased the nuclear Nrf2 and γ-glu-tamylcysteine synthetase expression at 6 h of recovery in these regions. We conclude that systemic administration of sulforaphane 15 min after HI can induce the translocation of Nrf2 to the nucleus, increase expression of an enzyme involved in glutathione synthesis, and salvage neurons in the highly vulnerable putamen and sensorimotor cortex in a large-animal model of HI. Therefore, targeting Nrf2 activation soon after recovery from HI is a feasible approach for neuroprotection in the newborn brain.

Long-term neurocognitive and educational outcomes of neonatal insults in Kilifi, Kenya

BACKGROUND

There is little data on the long-term neurocognitive and educational outcomes among school-aged survivors of neonatal jaundice (NNJ) and hypoxic-ischemic encephalopathy (HIE) in Africa. This study investigates the long-term neurocognitive and educational outcomes and the correlates of these outcomes in school-aged survivors of NNJ or HIE in Kilifi, Kenya.

METHODS

We conducted a cross-sectional study on neurocognitive and educational outcomes among school-aged survivors (6-12 years) of NNJ (n = 134) and HIE (n = 107) and compared them to a community comparison group (n = 134). We assessed nonverbal intelligence, planning, working memory, attention, syntax, pragmatics, word-finding, memory, perceptual-motor, mathematical, and reading abilities. We also collected information on medical history, caregivers' mental health, and family environment.

RESULTS

The survivors of NNJ had lower mean total scores in word-finding [F (1, 250) = 3.89, p = 0.050] and memory [F (1, 248) = 6.74, p = 0.010] than the comparison group. The survivors of HIE had lower mean scores in pragmatics [F (1, 230) = 6.61, p = 0.011] and higher scores higher scores in non-verbal reasoning [F (1, 225) =4.10, p = 0.044] than the comparison group. Stunted growth was associated with almost all the outcomes in HIE.

CONCLUSION

Survivors of NNJ and HIE present with impairment in the multiple domains, which need to be taken into consideration in the planning of educational and rehabilitative services.

Vof-16 knockout improves the recovery from hypoxic-ischemic brain damage of neonatal rats

Hypoxic-ischemic encephalopathy (HIE) results in high neonatal mortality and severe neurological impairments, and its underlying molecular mechanism underwent extensive investigations. Long non-coding RNA (lncRNA) is considered to be an important regulator on brain development and many neurological diseases. Currently, little is known about the role of Vof-16 (lncRNA) in HIE. We detected the relative expression level of Vof-16 in the cortex and hippocampus of hypoxic-ischemic (HI) models whose successful establishment was verified by TTC staining. Then, Vof-16 knockout rats were generated using the CRISPR/Cas engineering technology to search the specific function of the Vof-16 through a series of behavioral evaluations including Neurological severity scores (NSS), Y-maze test, Morris water maze (MWW) test, open field test, and Rotarod test. The results demonstrated the expression of Vof-16 was substantially up-regulated in the cortex and hippocampus of rats with HI injury. Importantly, Vof-16 knockout facilitated the recovery from long-term HI induced nerve damage and neurobehavioral dysfunctions. In conclusion, this study suggests Vof-16 knockout is a promising treatment target for neonatal HIE.

Brain-targeted hypoxia-inducible factor stabilization reduces neonatal hypoxic-ischemic brain injury

Hypoxia-inducible factor-1α (HIF1α) is a major regulator of cellular adaptation to hypoxia and oxidative stress, and recent advances of prolyl-4-hydroxylase (P4H) inhibitors have produced powerful tools to stabilize HIF1α for clinical applications. However, whether HIF1α provokes or resists neonatal hypoxic-ischemic (HI) brain injury has not been established in previous studies. We hypothesize that systemic and brain-targeted HIF1α stabilization may have divergent effects. To test this notion, herein we compared the effects of GSK360A, a potent P4H inhibitor, in in-vitro oxygen-glucose deprivation (OGD) and in in-vivo neonatal HI via intracerebroventricular (ICV), intraperitoneal (IP), and intranasal (IN) drug-application routes. We found that GSK360A increased the erythropoietin (EPO), heme oxygenase-1 (HO1) and glucose transporter 1 (Glut1) transcripts, all HIF1α target-genes, and promoted the survival of neurons and oligodendrocytes after OGD. Neonatal HI insult stabilized HIF1α in the ipsilateral hemisphere for up to 24 h, and either ICV or IN delivery of GSK360A after HI increased the HIF1α target-gene transcripts and decreased brain damage. In contrast, IP-injection of GSK360A failed to reduce HI brain damage, but elevated the risk of mortality at high doses, which may relate to an increase of the kidney and plasma EPO, leukocytosis, and abundant vascular endothelial growth factor (VEGF) mRNAs in the brain. These results suggest that brain-targeted HIF1α-stabilization is a potential treatment of neonatal HI brain injury, while systemic P4H-inhibition may provoke unwanted adverse effects.

Radiographic and clinical neurologic manifestations of COVID-19 related hypoxemia

The novel coronavirus SARS-CoV-2 is known to cause hypoxemia and acute respiratory distress syndrome (ARDS) in a significant portion of those with severe disease. Survivors of critical illness and ARDS often experience neurocognitive impairment but, to date, there is scant literature correlating radiographic hypoxic brain injury to hypoxemia related to ARDS. In this case series, we describe three cases of hypoxic brain injury seen on magnetic resonance imaging (MRI) in patients with hypoxemia secondary to COVID-19-related ARDS. The lack of severe observed hypoxemia in two of the cases suggests that unrecognized or asymptomatic hypoxemia may play a role in hypoxic brain injury related to COVID-19.

Early neutrophil infiltration is critical for inflammation-sensitized hypoxic-ischemic brain injury in newborns

Neutrophils are the most abundant leukocytes and usually the first immune cell-type recruited to a site of infection or tissue damage. In asphyxiated neonates, elevated peripheral neutrophil counts are associated with poorer neurological outcomes. Induced neutropenia provides brain protection in animal models of neonatal hypoxic-ischemic (HI) injury, but the anti-neutrophil serum used in past studies heavily cross-reacts with monocytes, thus complicating the interpretation of results. Here we examined neutrophil influx and extravasation, and used a specific anti-Ly6G antibody for induced neutropenia against lipopolysaccharide (LPS)-pretreated HI injury in murine neonates, a model for inflammation-sensitized hypoxic-ischemic encephalopathy (HIE). As early as 6 h after the LPS/HI insult, the mRNAs for neutrophil-recruiting and mitogenic chemokines ascended in the ipsilateral hemisphere, coinciding with immuno-detection of neutrophils. However, neutrophils mainly resided within blood vessels, exhibiting signs for neutrophil extracellular traps (NETs), before 48 h post-LPS/HI. Prophylactic anti-Ly6G treatment blocked the brain infiltration of neutrophils, but not monocytes or lymphocytes, and markedly decreased LPS/HI-induced pro-inflammatory cytokines, matrix metalloproteinase 9 (MMP-9), and brain tissue loss. In contrast, anti-Ly6G treatment at 4 h post-LPS/HI failed to prevent the influx of neutrophils and brain damage. Together, these results suggest important pathological functions for early-arriving neutrophils in inflammation-sensitized HIE.

Seizure burden and neurodevelopmental outcome in newborns with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia: A single center observational study

OBJECTIVE

To examine the relationship between electrographic seizures and developmental outcome at 18 and 24 months in neonates with moderate and severe hypoxic-ischemic encephalopathy [HIE] treated with therapeutic hypothermia [TH].

STUDY DESIGN

30 term infants with moderate-severe HIE treated with TH were enrolled prospectively from June 2012 to May 2018. All had continuous single channel amplitude integrated EEG (aEEG) monitoring for a minimum of 72 h and brain MR within 4 weeks. The aEEG was classified by severity of background and seizure burden. MR images were graded by the severity of injury. Outcome (defined abnormal in case of death, dyskinetic or spastic quadriplegic cerebral palsy, epilepsy, or Bayley III score < 85 in all three subscales or < 70 in any individual subscale) was assessed at 18 and 24 months.

RESULTS

Seizures were recorded in 24 out of 30 [80 %] neonates and an abnormal outcome was observed in 7 [23 %] of infants. Patients with poor outcome had a statistically significant correlation with: high seizure burden (p = 0.0004), need for more than one antiepileptic drugs (p = 0.006), a persistent abnormal aEEG trace at 48 h (p = 0.0001) and moderate-severe brain injury at MRI (p = 0.0001). Moreover, infants with status epilepticus or frequent seizures reported a significantly association with abnormal MR imaging and poor outcome than patients with sporadic seizures (p = 0.0009).

CONCLUSION

The role of seizures in the pathogenesis of brain injury remains controversial. In our cohort the presence of seizures, per se, was not associated with abnormal outcome; however a high seizure burden as well as a persistent abnormal aEEG background pattern and MR lesions resulted significantly associated with poor prognosis.

Adenosine Receptor Modulation of Hypoxic-ischemic Injury in Striatum of Newborn Piglets

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a major cause of pediatric and adult mortality and morbidity. Unfortunately, to date, no effective treatment has been identified. In the striatum, neuronal injury is analogous to the cellular mechanism of necrosis observed during NMethyl- D-Aspartate (NMDA) excitotoxicity. Adenosine acts as a neuromodulator in the central nervous system, the role of which relies mostly on controlling excitatory glutamatergic synapses.

OBJECTIVE

To examine the effect of pretreatment of SCH58261, an adenosine 2A (A2A) receptor antagonist and modulator of NMDA receptor function, following hypoxic-ischemia (HI) on sodium- potassium ATPase (Na+, K+-ATPase) activity and oxidative stress.

METHODS

Piglets (4-7 days old) were subjected to 30 min hypoxia and 7 min of airway occlusion producing asphyxic cardiac arrest. Groups were divided into four categories: HI samples were divided into HI-vehicle group (n = 5) and HI-A2A group (n = 5). Sham controls were divided into Sham vehicle (n = 5) and Sham A2A (n = 5) groups. Vehicle groups were pretreated with 0.9% saline, whereas A2A animals were pretreated with SCH58261 10 min prior to intervention. Striatum samples were collected 3 h post-arrest. Sodium-potassium ATPase (Na+, K+-ATPase) activity, malondialdehyde (MDA) + 4-hydroxyalkenals (4-HDA) and glutathione (GSH) levels were compared.

RESULTS

Pretreatment with SCH58261 significantly attenuated the decrease in Na+, K+-ATPase, decreased MDA+4-HDA levels and increased GSH in the HI-A2A group when compared to HIvehicle.

CONCLUSION

A2A receptor activation may contribute to neuronal injury in newborn striatum after HI in association with decreased Na+, K+-ATPase activity and increased oxidative stress.

Cerebral Autoregulation in Sick Infants: Current Insights

Cerebrovascular autoregulation is the ability to maintain stable cerebral blood flow within a range of cerebral perfusion pressures. When cerebral perfusion pressure is outside the limits of effective autoregulation, the brain is subjected to hypoperfusion or hyperperfusion, which may cause vascular injury, hemorrhage, and/or hypoxic white matter injury. Infants born preterm, after fetal growth restriction, with congenital heart disease, or with hypoxic-ischemic encephalopathy are susceptible to a failure of cerebral autoregulation. Bedside assessment of cerebrovascular autoregulation would offer the opportunity to prevent brain injury. Clinicians need to know which patient populations and circumstances are associated with impaired/absent cerebral autoregulation.

Evaluation of the role of ischemia modified albumin in neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Birth asphyxia is a leading cause of neonatal mortality. Ischemia-modified albumin (IMA) levels may have a predictive role in the identification and prevention of hypoxic disorders, as they increase in cases of ischemia of the liver, heart, brain, bowel, and kidney.

PURPOSE

This study aimed to assess the value of IMA levels as a diagnostic marker for neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

Sixty newborns who fulfilled 3 or more of the clinical and biochemical criteria and developed HIE as defined by Levene staging were included in our study as the asphyxia group. Neonates with congenital malformation, systemic infection, intrauterine growth retardation, low-birth weight, cardiac or hemolytic disease, family history of neurological diseases, congenital or perinatal infections, preeclampsia, diabetes, and renal diseases were excluded from the study. Sixty healthy neonates matched for gestational age and with no maternal history of illness, established respiration at birth, and an Apgar score ≥7 at 1 and 5 minutes were included as the control group. IMA was determined by double-antibody enzymelinked immunosorbent assay of a cord blood sample collected within 30 minutes after birth.

RESULTS

Cord blood IMA levels were higher in asphyxiated newborns than in controls (250.83±36.07 pmol/mL vs. 120.24±38.9 pmol/mL). Comparison of IMA levels by HIE stage revealed a highly significant difference among them (207.3±26.65, 259.28±11.68, 294.99±4.41 pmol/mL for mild, moderate, and severe, respectively). At a cutoff of 197.6 pmol/mL, the sensitivity was 84.5%, specificity was 86%, positive predictive value was 82.8%, negative predictive value was 88.3%, and area under the curve was 0.963 (P<0.001).

CONCLUSION

IMA levels can be a reliable marker for the early diagnosis of neonatal HIE and can be a predictor of injury severity.

FIRS: Neonatal considerations

Fetal Inflammatory Response Syndrome (FIRS) is the fetal counterpart of systemic inflammatory response syndrome (SIRS) described in adults. When the fetus is directly exposed to inflammation of the fetal membranes or the placental-fetal circulation, and organs are adversely affected, the disorder is known as FIRS. This syndrome can significantly affect multiple organs with significant short and long term implications for the newborn. In cases of neonatal encephalopathy when no obvious etiology is identified, FIRS needs to be considered. Based on the significant incidence of chorioamnionitis and its potential effects on the newborn, any evidence of maternal, fetal, or neonatal infection should mandate further evaluation of the placenta and membrane histopathology.

Evaluation for the etiology of neonatal encephalopathy and the diagnosis of FIRS

A common disorder managed in the neonatal intensive care unit (NICU) is neonatal encephalopathy (NE). There are multiple causes of NE, including hypoxic-ischemic encephalopathy (HIE) and the fetal inflammatory response syndrome (FIRS). It is important to ascertain the specific cause of NE in an affected child, as it may affect the clinical management and will assist in prognostication. This paper discusses the background of inflammatory damage to the fetal brain, the history of FIRS as a clinical diagnosis, the characteristics of infants with FIRS, and methods to evaluate the etiology of NE.

Deregulated miR-384 serves as a biomarker in neonatal hypoxic-ischemic encephalopathy and alleviates microglia-mediated neuroinflammation

Microglia-mediated neuroinflammation is important in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (HIE). This study aimed to investigate the expression of microRNA-384 (miR-384) in HIE newborns and evaluate the clinical and functional role of miR-384 in HIE diagnosis and neuroinflammation. The expression of miR-384 was estimated using quantitative real-time PCR. The levels of proinflammatory cytokines were examined using ELISA. Receiver operating characteristic (ROC) analysis was applied to evaluate the diagnostic performance of miR-384. The oxygen-glucose deprivation (OGD) experiment was adopted to activate primary neonatal microglia. A putative target of miR-384 was analyzed by bioinformatics prediction and a luciferase reporter assay. The expression of miR-384 was decreased in the serum of HIE newborns and OGD-induced activated microglia. Serum miR-384 had relatively high diagnostic accuracy for the screening of HIE cases from healthy newborns and the differentiation between newborns with different HIE severities. The OGD-induced increase in microglial neuroinflammation was significantly attenuated by the overexpression of miR-384, and AKT3, as a downstream target of miR-384, was inhibited by miR-384 in activated microglia. The data of this study demonstrated that decreased serum miR-384 expression may be a novel noninvasive biomarker for the diagnosis and progression of neonatal HIE. miR-384 can inhibit the neuroinflammation in activated microglia, which may be mediated by targeting AKT3.

MiR-410-3p overexpression ameliorates neurological deficits in rats with hypoxic-ischemic brain damage

Neonatal hypoxic-ischemic encephalopathy (HIE) is major cause of neonatal death or long-term neurodevelopmental disabilities, which becomes a major practical problem currently in clinic. Whereas, its pathophysiology and underlying molecular mechanism is not clear. MicroRNAs are involved in the normal growth and development of neuronal cells. Herein, the objective of this research was to examine the roles of miR-410-3p in neurological deficits, neuronal injury and neuron apoptosis after hypoxic-ischemic and to explore its associated mechanisms. We established the hypoxic-ischemic brain damage (HIBD) model and oxygen glucose deprivation (OGD) model. Zea-longa score and TTC staining were used to detect the acute cerebral dysfunction after HIBD. QPCR verification exhibited notable downregulation of miR-410-3p expression at 24 h in rats after HIBD as well as that in PC12, SY5Y cells and primary cortical neurons post OGD. To further determine the function of miR-410-3p, lentivirus-mediated overexpression virus was applied in vivo and in vitro. Behavioral tests, including Morris water maze, open field test, Y maze test, neurological severity score and rotating rod test, were performed to evaluate long-term behavioral changes of rats at 1 month post HIBD. The results showed that the number of cells together with the axonal length were reduced post OGD. While the increase of cells number and the axonal length was measured after upregulating miR-410-3p. Meanwhile, miR-410-3p overexpression inhibited neuron apoptosis and enhanced neuronal survival. In addition, long-term motor and cognitive functions were remarkably recovered in HIBD rats with miR-410-3p overexpression. Together, miR-410-3p exerts a critical role in protecting neuronal growth as well as promoting motor and cognitive function recovery in neonatal rats subjected to HIBD. The current study therefore provides critical insights to develop the activator of miR-410-3p for the clinical treatment of HIBD in future clinic trial.

Synthesis, pharmacological evaluation and mechanistic study of scutellarin methyl ester -4'-dipeptide conjugates for the treatment of hypoxic-ischemic encephalopathy (HIE) in rat pups

A series of novel scutellarin methyl ester-4'-dipeptide conjugates exhibiting active transport characteristics and protection against pathological damage caused by hypoxic-ischemic encephalopathy (HIE) were successfully designed and synthesized. The physiochemical properties of the obtained compounds, as well as the Caco-2 cell-based permeability and uptake into hPepT1-MDCK cells were evaluated using various analytical methods. Scutellarin methyl ester-4'-Val-homo-Leu dipeptide (5k) was determined as the optimal candidate with a high apparent permeability coefficient (P_{app A to B}) of 1.95 ± 0.24 × 10^-6 cm/s, low ER (P_{app BL to AP}/P_{app AP to BL}) of 0.52 in Caco-2 cells, and high uptake of 25.47 μmol/mg/min in hPepT1-MDCK cells. Comprehensive mechanistic studies demonstrated that pre-treatment of PC12 cells with 5k resulted in more potent anti-oxidative activity, which was manifested by a significant decrease in the malondialdehyde (MDA) and reactive oxygen species (ROS) levels, attenuation of the H₂O₂-induced apoptotic cell accumulation in the sub-G1 peak, and improvement in the expression of the relevant apoptotic proteins (Bcl-2, Bax, and cleave-caspase-3). Moreover, evaluation of in vivo neuroprotective characteristics in hypoxic-ischemic rat pups revealed that 5k significantly reduced infarction and alleviated the related pathomorphological damage. The compound was also shown to ameliorate the neurological deficit at 48 h as well as to decrease the brain tissue loss at 4 weeks. Conjugate 5k was demonstrated to reduce the amyloid precursor protein (APP) and β-site APP-converting enzyme-1 (BACE-1) expression. Pharmacokinetic characterization of 5k indicated favorable druggability and pharmacokinetic properties. The conducted docking studies revealed optimal binding of 5k to PepT1. Hydrogen bonding as well as cation-π interactions with the corresponding amino acid residues in the target active site were clearly observed. The obtained results suggest 5k as a potential candidate for anti-HIE therapy, which merits further investigation.

Prognostic value of magnetic resonance imaging performed during the subacute phase in adult patients with hypoxic-ischemic encephalopathy for long-term neurological outcomes

OBJECTIVE

To investigate the value of a model based on brain magnetic resonance imaging (MRI) performed in the subacute phase (between the 1st and 30th day) in predicting long-term neurological outcomes of adult hypoxic-ischemic encephalopathy (HIE) patients.

METHODS

Ninety-six adult HIE patients who underwent conventional MRI and diffusion-weighted imaging (DWI) during the subacute phase were retrospectively analyzed. Favorable (Cerebral Performance Categories (CPC) 1-2) and unfavorable outcome (CPC 3-5) groups were created based on patient neurological status approximately three months after the onset of hypoxic-ischemic events. A multivariate stepwise regression model was applied after univariate analysis of MRI findings, and then the overall MRI score, Alberta Stroke Program Early Computed Tomography Score (ASPECTS), Bilateral ASPECTS (Bi-ASPECTS), modified ASPECTS (mASPECTS) and Bi-ASPECTS combined with posterior circulation ASPECTS (PC-ASPECTS) were calculated based on MRI findings. Receiver operating characteristic (ROC) curves were used to assess prognostic accuracy.

RESULTS

Both univariate and multivariate analyses showed the cerebral cortex and cerebellum, neostriatum, hippocampus, brainstem and postanoxic leukoencephalopathy were independent prognostic factors for unfavorable outcomes. The multivariate regression analysis resulted in an overall classification accuracy of 84.4%, a sensitivity of 84.2% (95% CI, 71.6-92.1%), and a specificity of 92.3% (95% CI, 78.0-98.0%) for unfavorable outcomes. The model had an areas under the ROC curves (AUC) of 0.944 (95% CI, 0.901-0.987); the MRI overall scores were 0.918 (95% CI, 0.866, 0.971), ASPECTS 0.839 (95% CI, 0.755, 0.923), Bi-ASPECTS 0.837 (95% CI, 0.753, 0.922), mASPECTS 0.851(95% CI, 0.771, 0.931) and Bi-ASPECTS+PC-ASPECTS 0.876 (95% CI, 0.806, 0.946).

CONCLUSIONS

The multivariate model based on conventional MRI combined with DWI performed in the subacute phase could help predict the prognosis of adult HIE with high performance.

Rh-CSF1 attenuates neuroinflammation via the CSF1R/PLCG2/PKCε pathway in a rat model of neonatal HIE

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a life-threatening cerebrovascular disease. Neuroinflammation plays an important role in the pathogenesis of HIE, in which microglia are key cellular mediators in the regulation of neuroinflammatory processes. Colony-stimulating factor 1 (CSF1), a specific endogenous ligand of CSF1 receptor (CSF1R), is crucial in microglial growth, differentiation, and proliferation. Recent studies showed that the activation of CSF1R with CSF1 exerted anti-inflammatory effects in a variety of nervous system diseases. This study aimed to investigate the anti-inflammatory effects of recombinant human CSF1 (rh-CSF1) and the underlying mechanisms in a rat model of HIE.

METHODS

A total of 202 10-day old Sprague Dawley rat pups were used. HI was induced by the right common carotid artery ligation with subsequent exposure of 2.5-h hypoxia. At 1 h and 24 h after HI induction, exogenous rh-CSF1 was administered intranasally. To explore the underlying mechanism, CSF1R inhibitor, BLZ945, and phospholipase C-gamma 2 (PLCG2) inhibitor, U73122, were injected intraperitoneally at 1 h before HI induction, respectively. Brain infarct area, brain water content, neurobehavioral tests, western blot, and immunofluorescence staining were performed.

RESULTS

The expressions of endogenous CSF1, CSF1R, PLCG2, protein kinase C epsilon type (PKCε), and cAMP response element-binding protein (CREB) were gradually increased after HIE. Rh-CSF1 significantly improved the neurological deficits at 48 h and 4 weeks after HI, which was accompanied by a reduction in the brain infarct area, brain edema, brain atrophy, and neuroinflammation. Moreover, activation of CSF1R by rh-CSF1 significantly increased the expressions of p-PLCG2, p-PKCε, and p-CREB, but inhibited the activation of neutrophil infiltration, and downregulated the expressions of IL-1β and TNF-α. Inhibition of CSF1R and PLCG2 abolished these neuroprotective effects of rh-CSF1 after HI.

CONCLUSIONS

Our findings demonstrated that the activation of CSF1R by rh-CSF1 attenuated neuroinflammation and improved neurological deficits after HI. The anti-inflammatory effects of rh-CSF1 partially acted through activating the CSF1R/PLCG2/PKCε/CREB signaling pathway after HI. These results suggest that rh-CSF1 may serve as a potential therapeutic approach to ameliorate injury in HIE patients.

Clinical application of target temperature management in children with acute encephalopathy-A practical review

Acute encephalopathy is a life-threatening disease involving acute brain dysfunction, and it is one of the most important causes of mortality and severe neurological sequelae in infants and children. Approximately 30% of cases of acute encephalopathy result in some degree of neurological sequelae. Although many strategies have been proposed, effective therapies to ameliorate the outcomes of acute encephalopathy have not yet been established. Target temperature management (TTM), previously termed therapeutic hypothermia, has been shown to be effective for various brain injuries due to multiple neuroprotective mechanisms, and it may be considered to be the cornerstone of neuroprotective strategies. Consequently, TTM is currently used in the neurocritical care of adult patients with cardiac arrest with shockable rhythm and perinatal asphyxia. In addition, increasing evidence also indicates that TTM could be useful in other acute encephalopathies, including status epilepticus, acute encephalitis/encephalopathy and traumatic brain injury. In this review, we discuss the recent practical aspects of TTM as a potential intervention for various acute encephalopathies in children.

Identification of novel biomarkers for neonatal hypoxic-ischemic encephalopathy using iTRAQ

Background

A prompt diagnosis of HIE remains a challenge clinically. This study aimed to identify potential biomarkers of neonatal hypoxic-ischemic encephalopathy (HIE) via a novel proteomic approach, the isobaric tags for absolute and relative quantification (iTRAQ) method.

Methods

Blood samples were collected from neonates with mild (n = 4), moderate (n = 4), or severe (n = 4) HIE who were admitted to the neonatal intensive care unit of Children’s Hospital of Soochow University between Oct 2015 and Oct 2017. iTRAQ was performed in HIE patients and healthy controls (n = 4). Bioinformatics analyses including Gene Ontology and KEGG pathway enrichment analysis were performed to evaluate the potential features and capabilities of the identified differentially expressed proteins.

Results

A total of 51 commonly differentially expressed proteins were identified among the comparisons between mild, moderate, and severe HIE as well as healthy controls. Haptoglobin (HP) and S100A8 were most significantly up-regulated in patients with HIE and further validated via real-time PCR and western blotting. The differentially expressed proteins represented multiple biological processes, cellular components and molecular functions and were markedly enriched in complement and coagulation cascades.

Conclusions

HP and S100A8 may serve as a potential biomarker for neonatal HIE and reflects the severity of HIE. The complement and coagulation cascades play crucial roles in the development of neonatal HIE.

IRE1α inhibition attenuates neuronal pyroptosis via miR-125/NLRP1 pathway in a neonatal hypoxic-ischemic encephalopathy rat model

BACKGROUND

Inhibition of inositol-requiring enzyme-1 alpha (IRE1α), one of the sensor signaling proteins associated with endoplasmic reticulum (ER) stress, has been shown to alleviate brain injury and improve neurological behavior in a neonatal hypoxic-ischemic encephalopathy (HIE) rat model. However, there is no information about the role of IRE1α inhibitor as well as its molecular mechanisms in preventing neuronal pyroptosis induced by NLRP1 (NOD-, LRR- and pyrin domain-containing 1) inflammasome. In the present study, we hypothesized that IRE1α can degrade microRNA-125-b-2-3p (miR-125-b-2-3p) and activate NLRP1/caspased-1 pathway, and subsequently promote neuronal pyroptosis in HIE rat model.

METHODS

Ten-day old unsexed rat pups were subjected to hypoxia-ischemia (HI) injury, and the inhibitor of IRE1α, STF083010, was administered intranasally at 1 h after HI induction. AntimiR-125 or NLRP1 activation CRISPR was administered by intracerebroventricular (i.c.v) injection at 24 h before HI induction. Immunofluorescence staining, western blot analysis, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), brain infarct volume measurement, neurological function tests, and Fluoro-Jade C staining were performed.

RESULTS

Endogenous phosphorylated IRE1α (p-IRE1α), NLRP1, cleaved caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18) were increased and miR-125-b-2-3p was decreased in HIE rat model. STF083010 administration significantly upregulated the expression of miR-125-b-2-3p, reduced the infarct volume, improved neurobehavioral outcomes and downregulated the protein expression of NLRP1, cleaved caspase-1, IL-1β and IL-18. The protective effects of STF083010 were reversed by antimiR-125 or NLRP1 activation CRISPR.

CONCLUSIONS

IRE1α inhibitor, STF083010, reduced neuronal pyroptosis at least in part via miR-125/NLRP1/caspase-1 signaling pathway after HI.

Impact of Erythropoietin in the management of Hypoxic Ischaemic Encephalopathy in resource-constrained settings: protocol for a randomized control trial

Background

Perinatal asphyxia, more appropriately known as hypoxic-ischemic encephalopathy (HIE), is a condition characterized by clinical and laboratory evidence of acute or sub-acute brain injury resulting from systemic hypoxemia and/or reduced cerebral blood flow. HIE is a common and devastating clinical condition in resource-poor countries with poor treatment outcome. This paper describes the protocol for an ongoing study that aims to evaluate the neuroprotective effects of Erythropoietin (EPO) as compared to routine care in the management of moderate to severe HIE among term infants.

Methods

This study is a double-blind randomized controlled trial that will be conducted in the neonatal wards of the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria, over a two-year period after ethical approvals and consents. One hundred and twenty-eight term newborns (≥ 37 weeks gestation) diagnosed with moderate/ severe HIE at admission will be allocated by randomization to receive either EPO or normal saline. All the participants will be offered standard care according to the unit protocol for HIE. Baseline investigations and close monitoring of the babies are done until discharge. Participants are followed up for 2 years to monitor their outcome (death or neurological development) using standard instruments.

Discussion

Previous trials had shown that EPO confers neuroprotective benefits and improve neurological and behavioral outcome in infants with HIE both singly or as an adjuvant to therapeutic hypothermia. This study hypothesized that administering EPO to newborns with moderate /severe HIE can positively influence their clinical and neurological outcomes and will provide evidence to either support or disprove the usefulness of Erythropoietin as a sole agent in the treatment of HIE, especially in resource-limited environment with the highest burden of the disease.

Trial registration

The study has been registered with the Pan African Clinical trials registry on the 2nd of December 2018, with registration number PACTR201812814507775.

MicroRNA-374a-5p inhibits neuroinflammation in neonatal hypoxic-ischemic encephalopathy via regulating NLRP3 inflammasome targeted Smad6

AIMS

Neonatal hypoxic-ischemic encephalopathy (HIE) is still an important cause of neurological dysfunction. At present, there is no reliable biochemical index in clinical examination. Increasing evidence demonstrates that microRNAs (miRNAs) are involved in the process of HIE, and miR-374a-5p is down-regulated in HIE infants. In this study, the aim is to investigate the role and mechanism of miR-374a-5p in HIE.

MAIN METHODS

Sprague-Dawley (SD) rats were used to establish model of neonatal HIE, pathologic changes and inflammatory response of brain tissues were measured. Subsequently, primary microglia were induced by LPS (1 μg/ml) in vitro, the miR-374a-5p mimic, Ad-Smad6 adenovirus vector and NLRP3 siRNA oligo were applied for microglial transfection. Furthermore, the target relationship between miR-374a-5p and Smad6 was analyzed, while microglia activity and inflammatory factor (IL-1β, TNF-α and IL-6) levels were detected.

KEY FINDINGS

Herein, we found that over-expression of miR-374a-5p significantly attenuated brain injury and strongly inhibited the release of pro-inflammatory cytokines in neonatal rat HIE model. In vitro, miR-374a-5p inhibited LPS-induced microglial pro-inflammatory cytokines production by regulating NLRP3 inflammasome. In addition, Smad6 was identified as a direct target of miR-374a-5p, and miR-374a-5p had a negative regulatory effect on Smad6 expression. By targeting Smad6, miR-374a-5p inhibited the activation of NLRP3 inflammatory signals in microglia and the subsequent release of pro-inflammatory factors.

SIGNIFICANCE

Our study recognized that miR-374a-5p as a novel regulator of microglial activation in neonatal HIE highlighted potential therapeutic target for the treatment of neonatal hypoxic-ischemic brain injury.