Birth Asphyxia Is Associated With Increased Risk of Cerebral Palsy: A Meta-Analysis

Genetic pathways in cerebral palsy: a review of the implications for precision diagnosis and understanding disease mechanisms

ABSTRACT

Cerebral palsy is a diagnostic term utilized to describe a group of permanent disorders affecting movement and posture. Patients with cerebral palsy are often only capable of limited activity, resulting from non-progressive disturbances in the fetal or neonatal brain. These disturbances severely impact the child's daily life and impose a substantial economic burden on the family. Although cerebral palsy encompasses various brain injuries leading to similar clinical outcomes, the understanding of its etiological pathways remains incomplete owing to its complexity and heterogeneity. This review aims to summarize the current knowledge on the genetic factors influencing cerebral palsy development. It is now widely acknowledged that genetic mutations and alterations play a pivotal role in cerebral palsy development, which can be further influenced by environmental factors. Despite continuous research endeavors, the underlying factors contributing to cerebral palsy remain are still elusive. However, significant progress has been made in genetic research that has markedly enhanced our comprehension of the genetic factors underlying cerebral palsy development. Moreover, these genetic factors have been categorized based on the identified gene mutations in patients through clinical genotyping, including thrombosis, angiogenesis, mitochondrial and oxidative phosphorylation function, neuronal migration, and cellular autophagy. Furthermore, exploring targeted genotypes holds potential for precision treatment. In conclusion, advancements in genetic research have substantially improved our understanding of the genetic causes underlying cerebral palsy. These breakthroughs have the potential to pave the way for new treatments and therapies, consequently shaping the future of cerebral palsy research and its clinical management. The investigation of cerebral palsy genetics holds the potential to significantly advance treatments and management strategies. By elucidating the underlying cellular mechanisms, we can develop targeted interventions to optimize outcomes. A continued collaboration between researchers and clinicians is imperative to comprehensively unravel the intricate genetic etiology of cerebral palsy.

Prevalence of hearing impairment in neonatal encephalopathy due to hypoxia-ischemia: a systematic review and meta-analysis

BACKGROUND

This systematic review was undertaken to estimate the overall prevalence of hearing impairment in survivors of neonatal HIE.

METHODS

PubMed, EMBASE, CINAHL, EMCARE and Cochrane databases, mednar (gray literature) were searched till January 2023. Randomized controlled trials and observational studies were included. The main outcome was estimation of overall prevalence of hearing impairment in survivors of HIE.

RESULTS

A total of 71studies (5821 infants assessed for hearing impairment) were included of which 56 were from high income countries (HIC) and 15 from low- or middle-income countries (LMIC). Overall prevalence rate of hearing impairment in cooled infants was 5% (95% CI: 3-6%, n = 4868) and 3% (95% CI: 1-6%, n = 953) in non-cooled HIE infants. The prevalence rate in cooled HIE infants in LMICs was 7% (95% CI: 2-15%) and in HICs was 4% (95% CI: 3-5%). The prevalence rate in non-cooled HIE infants in LMICs was 8% (95% CI: 2-17%) and HICs was 2% (95% CI: 0-4%).

CONCLUSIONS

These results would be useful for counseling parents, and in acting as benchmark when comparing institutional data, and while monitoring future RCTs testing new interventions in HIE. There is a need for more data from LMICs and standardization of reporting hearing impairment.

IMPACT

The overall prevalence rate of hearing impairment in cooled infants with HIE was 5% (95% CI: 3-6%) and 3% (95% CI: 1-6%) in the non-cooled infants. The prevalence rate in cooled HIE infants in LMICs was 7% (95% CI: 2-15%) and in HICs was 4% (95% CI: 3-5%). The prevalence rate in non-cooled HIE infants in LMICs was 8% (95% CI: 2-17%) and HICs was 2% (95% CI: 0-4%). These results would be useful for counseling parents, and in acting as benchmark when comparing institutional data, and while monitoring future RCTs testing new interventions in HIE.

Cerebral Palsy Heterogeneity: Clinical Characteristics and Diagnostic Significance from a Large-Sample Analysis

INTRODUCTION

Cerebral palsy (CP) is a nonprogressive movement disorder resulting from a prenatal or perinatal brain injury that benefits from early diagnosis and intervention. The timing of early CP diagnosis remains controversial, necessitating analysis of clinical features in a substantial cohort.

METHODS

We retrospectively reviewed medical records from a university hospital, focusing on children aged ≥24 months or followed up for ≥24 months and adhering to the International Classification of Diseases-10 for diagnosis and subtyping.

RESULTS

Among the 2012 confirmed CP cases, 68.84% were male and 51.44% had spastic diplegia. Based on the Gross Motor Function Classification System (GMFCS), 62.38% were in levels I and II and 19.88% were in levels IV and V. Hemiplegic and diplegic subtypes predominantly fell into levels I and II, while quadriplegic and mixed types were mainly levels IV and V. White matter injuries appeared in 46.58% of cranial MRI findings, while maldevelopment was rare (7.05%). Intellectual disability co-occurred in 43.44% of the CP cases, with hemiplegia having the lowest co-occurrence (20.28%, 58/286) and mixed types having the highest co-occurrence (73.85%, 48/65). Additionally, 51.67% (697/1,349) of the children with CP aged ≥48 months had comorbidities.

CONCLUSIONS

This study underscores white matter injury as the primary CP pathology and identifies intellectual disability as a common comorbidity. Although CP can be identified in infants under 1 year old, precision in diagnosis improves with development. These insights inform early detection and tailored interventions, emphasizing their crucial role in CP management.

Risk Factors for Birth Asphyxia in Hospital-Delivered Newborns in Dodoma, Tanzania: A Case-Control Study

Introduction

Asphyxia at birth remains the leading cause of neonatal morbidity and mortality worldwide, accounting for ∼23% of all neonatal deaths. Although the causes vary from country to country, early identification and treatment of risk factors can improve the situation.

Objectives

To determine the risk factors of birth asphyxia in hospital-delivered neonates in Dodoma, Tanzania.

Methods

A matched case-control study was conducted from May to July 2017 at Dodoma Region Referral Hospital. Data were collected using a semistructured questionnaire and a standard antenatal care index card. Cases were neonates diagnosed with asphyxia at birth (N  =  100), while controls were neonates not diagnosed with asphyxia at birth (N  =  300). A binary logistic regression model was used to assess the independent variables associated with birth asphyxia and reported as crude and adjusted odds ratios along with their 95% confidence intervals.

Results

A total of 400 newborns and their birth mothers were involved in the study. The average age of the case mothers was 26.9 years (SD  =  7.85) and that of the control mothers was 27.24 years (SD  =  6.08). Place of residence, anemia, maternal age, prenatal visits attended, use of herbs during labor, previously complicated pregnancy, duration of labor, meconium-stained amniotic fluid, and mode of delivery were predictors of birth asphyxia.

Conclusion

The study showed that most predictors of birth asphyxia can be prevented. The results suggest appropriate health education before conception, effective follow-up through prenatal care, early identification and treatment of high-risk pregnant women, and proper monitoring of labor and delivery.

The Application Value of Combined Detection of Serum IL-6, LDH, S100, NSE, and GFAP in the Early Diagnosis of Brain Damage Caused by Neonatal Asphyxia

Background

We aimed to investigate the correlation and clinical significance between a group of serum biomarkers and brain damage caused by neonatal asphyxia, and to provide sensitive and effective detection methods for early diagnosis and prognosis improvement.

Methods

We enrolled neonates hospitalized in the neonatal department of The Affiliated Hospital of Inner Mongolia Medical University of China from June 2020 to June 2021 as the study subjects. The levels of inter-leukin-6 (IL-6), lactate dehydrogenase (LDH), S100 protein, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP) in serum samples were measured using electrochemiluminescence (ECL), enzyme-linked immunosorbent assay (ELISA) or rate method and the correlations between these serum biomarkers and the degree of neonatal asphyxia and brain damage were statistically analyzed using Spearman test.

Results

The levels of serum IL-6, LDH, S100, NSE, and GFAP in the neonatal asphyxia with brain damage group within 12 hours after birth were significantly higher than those in the neonatal asphyxia without brain damage group (all P<0.05). Additionally, these levels were positively correlated with the degree of asphyxia. The Area Under the Curve (AUC) of receiver operating characteristic (ROC) curves of IL-6 (0.8819), LDH (0.8108), S100 (0.8719), NSE (0.8719), and GFAP (0.8073) were revealed.

Conclusion

The combined detection of serum marker levels can simultaneously reflect neuronal injury, glial cell injury, and inflammatory injury, improve the accuracy of diagnosis of neonatal asphyxia with brain damage, and enable the formulation of treatment strategies as early as possible to reduce the incidence of complications of brain damage.

Case report: Suspecting guanine nucleotide-binding protein beta 1 mutation in dyskinetic cerebral palsy is important

Herein, we describe the case of a 43-month-old girl who presented with clinical manifestations of dyskinetic cerebral palsy (CP), classified as the Gross Motor Function Classification System (GMFCS) V. The patient had no family history of neurological or perinatal disorders. Despite early rehabilitation, serial assessments using the Gross Motor Function Measure (GMFM) showed no significant improvements in gross motor function. Brain magnetic resonance imaging showed nonspecific findings that could not account for developmental delay or dystonia. Whole-genome sequencing identified a heterozygous NM_002074.5(GNB1):c.239T>C (p.Ile80Thr) mutation in guanine nucleotide-binding protein beta 1 (GNB1) gene. Considering this case and previous studies, genetic testing for the etiology of dyskinetic CP is recommended for children without relevant or with nonspecific brain lesions.

Effect of birth asphyxia on neonatal blood glucose during the early postnatal life: A multi-center study in Hubei Province, China

BACKGROUND

Birth asphyxia causes hypoxia or inadequate perfusion to the organs of newborns, leading to metabolism dysfunctions including blood glucose disorders.

METHODS

Neonates with and without birth asphyxia were retrospectively recruited from 53 hospitals in Hubei Province from January 1 to December 31, 2018. In summary, 875, 1139, and 180 cases in the control group, the mild asphyxia group, and the severe asphyxia group were recruited, respectively. Neonatal blood glucose values at postnatal 1, 2, 6, and 12 h (time error within 0.5 h was allowed) were gathered from the medical records.

RESULTS

The incidence rates of hyperglycemia in the control group, the mild asphyxia group and the severe asphyxia group were 2.97%, 7.90%, and 23.33%, respectively (p < 0.001). Additionally, the incidence rates of hypoglycemia in the three groups above were 3.66%, 4.13%, and 7.78%, respectively (p = 0.042). The blood glucose values of neonates with hypoglycemia in the asphyxia group were lower than in the control group (p = 0.003). Furthermore, the blood glucose values of neonates with hyperglycemia were highest in the severe asphyxia group (p < 0.001). There were 778 and 117 cases with blood glucose records at four predefined time points in the mild and severe asphyxia group, respectively. The incidence of blood glucose disorders in the mild asphyxia group significantly decreased from postnatal 6 h (p＜0.05). However, we found no obvious changes of the incidence of glucose disorders within postnatal 12 h in the severe asphyxia group (p = 0.589).

CONCLUSION

Birth asphyxia is likely to cause neonatal blood glucose disorders, both hypoglycemia and hyperglycemia, during the early postnatal life. The neonates with severe asphyxia have higher incidence, worse severity and longer duration of blood glucose disorders than neonates with mild asphyxia.

Current Concept and Management of Spastic Hip in Children: A Narrative Review

Cerebral palsy (CP) is a non-progressive motor condition that hinders the development of movement and posture. One of the common problems faced in CP is spastic hips, which can cause discomfort, deformity, and functional restrictions. This review article seeks to offer a thorough summary of the most recent methods for treating spastic hips in cerebral palsy patients. Additionally, it describes the success and potential risks of various conservative and surgical procedures. It also looks at new treatments and potential avenues for managing this complicated ailment.

Umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes in children: a systematic review and meta-analysis

BACKGROUND

Umbilical cord blood acid-base sampling is routinely performed at many hospitals. Recent studies have questioned this practice and the association of acidosis with cerebral palsy.

OBJECTIVE

To investigate the associations between the results of umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes and mortality in children.

SEARCH STRATEGY

We searched six databases using the search strategy: umbilical cord AND outcomes.

SELECTION CRITERIA

Randomised controlled trials, cohorts and case-control studies from high-income countries that investigated the association between umbilical cord blood analysis and neurodevelopmental outcomes and mortality from 1 year after birth in children born at term.

DATA COLLECTION AND ANALYSIS

We critically assessed the included studies, extracted data and conducted meta-analyses comparing adverse outcomes between children with and without acidosis, and the mean proportions of adverse outcomes. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach.

MAIN RESULTS

We have very low confidence in the following findings: acidosis was associated with higher cognitive development scores compared with non-acidosis (mean difference 5.18, 95% CI 0.84-9.52; n = two studies). Children with acidosis also showed a tendency towards higher risk of death (relative risk [RR] 5.72, 95% CI 0.90-36.27; n = four studies) and CP (RR 3.40, 95% CI 0.86-13.39; n = four studies), although this was not statistically significant. The proportion of children with CP was 2.39/1000 across the studies, assessed as high certainty evidence.

CONCLUSION

Due to low certainty of evidence, the associations between umbilical cord blood gas analysis at delivery and long-term neurodevelopmental outcomes in children remains unclear.

Implementation of Early Detection and Intervention for Cerebral Palsy in High-Risk Infant Follow-Up Programs: U.S. and Global Considerations

Early detection and intervention for cerebral palsy is best practice for all high-risk infants according to international guidelines, consensus statements and research-supported evidence. It allows support for families and optimization of developmental trajectories into adulthood. All phases of implementation of CP early detection can be found across the world in high-risk infant follow-up programs, demonstrating feasibility and acceptability through standardized implementation science. The largest clinical network for CP early detection and intervention in the world has now sustained an average age at detection less than 12 months corrected age for more than 5 years. Targeted referrals and interventions for CP can now be offered to patients in optimal periods of neuroplasticity, and new therapies researched as the age of detection decreases. Implementation of guidelines and incorporation of rigorous CP research studies both allow high-risk infant follow-up programs to fulfill their mission of improving outcomes of those with the most vulnerable developmental trajectories from birth.

The Effect of Maternal Coagulation Parameters on Fetal Acidemia in Placental Abruption

This study aimed to identify factors predicting the probability of serious fetal acidemia at delivery in placental abruption. We identified 5769 women who delivered at >22 weeks’ gestation at two institutions in a tertiary referral unit specializing in neonatal infant care between January 2007 and December 2011. Ninety-one abruption cases were identified based on clinical and histological diagnoses. Serious fetal acidemia was defined as a pH < 7.0 in the umbilical arterial blood at delivery. Using a linear discriminant function, we calculated the score to determine the probability of serious fetal acidemia. Serious fetal acidemia was observed in 34 patients (37.4%). A logistic regression model showed that abnormal fetal heart rate patterns (bradycardia and late decelerations), uterine spasm, and maternal plasma concentration of fibrinogen less than 288 ng/dL were significantly associated with the occurrence of serious fetal acidemia. We suggest that the implementation of maternal fibrinogen in patients with placental abruption is a prognostic factor for serious fetal acidemia at delivery.

Development and Validation of a Deep Learning Method to Predict Cerebral Palsy From Spontaneous Movements in Infants at High Risk

IMPORTANCE

Early identification of cerebral palsy (CP) is important for early intervention, yet expert-based assessments do not permit widespread use, and conventional machine learning alternatives lack validity.

OBJECTIVE

To develop and assess the external validity of a novel deep learning-based method to predict CP based on videos of infants' spontaneous movements at 9 to 18 weeks' corrected age.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study of a deep learning-based method to predict CP at a corrected age of 12 to 89 months involved 557 infants with a high risk of perinatal brain injury who were enrolled in previous studies conducted at 13 hospitals in Belgium, India, Norway, and the US between September 10, 2001, and October 25, 2018. Analysis was performed between February 11, 2020, and September 23, 2021. Included infants had available video recorded during the fidgety movement period from 9 to 18 weeks' corrected age, available classifications of fidgety movements ascertained by the general movement assessment (GMA) tool, and available data on CP status at 12 months' corrected age or older. A total of 418 infants (75.0%) were randomly assigned to the model development (training and internal validation) sample, and 139 (25.0%) were randomly assigned to the external validation sample (1 test set).

EXPOSURE

Video recording of spontaneous movements.

MAIN OUTCOMES AND MEASURES

The primary outcome was prediction of CP. Deep learning-based prediction of CP was performed automatically from a single video. Secondary outcomes included prediction of associated functional level and CP subtype. Sensitivity, specificity, positive and negative predictive values, and accuracy were assessed.

RESULTS

Among 557 infants (310 [55.7%] male), the median (IQR) corrected age was 12 (11-13) weeks at assessment, and 84 infants (15.1%) were diagnosed with CP at a mean (SD) age of 3.4 (1.7) years. Data on race and ethnicity were not reported because previous studies (from which the infant samples were derived) used different study protocols with inconsistent collection of these data. On external validation, the deep learning-based CP prediction method had sensitivity of 71.4% (95% CI, 47.8%-88.7%), specificity of 94.1% (95% CI, 88.2%-97.6%), positive predictive value of 68.2% (95% CI, 45.1%-86.1%), and negative predictive value of 94.9% (95% CI, 89.2%-98.1%). In comparison, the GMA tool had sensitivity of 70.0% (95% CI, 45.7%-88.1%), specificity of 88.7% (95% CI, 81.5%-93.8%), positive predictive value of 51.9% (95% CI, 32.0%-71.3%), and negative predictive value of 94.4% (95% CI, 88.3%-97.9%). The deep learning method achieved higher accuracy than the conventional machine learning method (90.6% [95% CI, 84.5%-94.9%] vs 72.7% [95% CI, 64.5%-79.9%]; P < .001), but no significant improvement in accuracy was observed compared with the GMA tool (85.9%; 95% CI, 78.9%-91.3%; P = .11). The deep learning prediction model had higher sensitivity among infants with nonambulatory CP (100%; 95% CI, 63.1%-100%) vs ambulatory CP (58.3%; 95% CI, 27.7%-84.8%; P = .02) and spastic bilateral CP (92.3%; 95% CI, 64.0%-99.8%) vs spastic unilateral CP (42.9%; 95% CI, 9.9%-81.6%; P < .001).

CONCLUSIONS AND RELEVANCE

In this prognostic study, a deep learning-based method for predicting CP at 9 to 18 weeks' corrected age had predictive accuracy on external validation, which suggests possible avenues for using deep learning-based software to provide objective early detection of CP in clinical settings.

Early Spontaneous Movements and Postural Patterns in Infants With Extremely Low Birth Weight

BACKGROUND

Extremely-low-birth-weight (ELBW) infants are at high risk of morbidity, mortality, and long-term neurodevelopmental disorders. Evaluating infants' early spontaneous movements and postural patterns could facilitate the early detection of neurological dysfunction. This study aimed to analyze the results of global-and detailed-General Movements Assessment (GMA) in ELBW infants at a corrected age of three to five months and to compare with normal-birth-weight (NBW) infants.

METHODS

Fifty-two ELBW infants (median birth weight = 915.5 g) and 50 NBW infants were included. All infants were assessed according to GMA using Motor Optimality Score for 3- to 5-Month-Old Infants-Revised score sheet (MOS-R). In addition, later diagnoses of ELBW infants with atypical development were presented.

RESULTS

Fidgety movements were observed in 36 (69.2%) of ELBW infants and all NBW infants. MOS-R scores were lower in the ELBW group (median = 24) compared with the NBW group (median = 26). The ELBW infants scored lower than NBW infants in all MOS-R subcategories. Twenty-three (44.2%) of ELBW infants were diagnosed as atypical in the later period, although all control infants had normal development.

CONCLUSIONS

The study indicated that ELBW might increase the risk of atypical development in infants. The MOS-R could help us to find the risk of atypical development in infants with ELBW.

The evaluation of the antepartum and intrapartum risk factors in predicting the risk of birth asphyxia

PURPOSE

This study aimed to determine the related antepartum and intrapartum factors of birth asphyxia among neonates born in a tertiary referral hospital.

METHODS

A total of 45 singleton pregnant women who delivered live births with a gestational age of ≥35 weeks and their neonates who suffered from birth asphyxia from June 2016 to June 2021 were included in this retrospective study. Data regarding maternal demographic features, maternal laboratory values, pregnancy complications, and obstetric and neonatal outcomes were collected.

RESULTS

Significant risk factors associated with birth asphyxia were nulliparity (odds ratio [OR] = 5.357, 95% confidence interval [CI] = 2.169-24.950, p = 0.001), placental abruption (OR = 8.667, 95% CI = 2.223-33.784, p = 0.002), intrauterine growth restriction (OR = 1.394, 95% CI = 1.109-8.631, p = 0.012), the prolonged second stage of labor (OR = 6.121, 95% CI = 2.120-17.595, p = 0.001), meconium-stained amniotic fluid (OR = 7.615, 95% CI = 2.394-24.223, p = 0.001), bloody amniotic fluid (OR = 9.423, 95% CI = 2.885-35.232, p = 0.001), the presence of FHR category II (OR = 12.083, 95% CI = 7.081-48.849, p <0.001) and FHR category III before labor (OR = 15.500, 95% CI = 8.394-56.176, p <0.001).

CONCLUSION

We identified that nulliparity, placental abruption, intrauterine growth restriction, the prolonged second stage of labor, meconium-stained or bloody amniotic fluid, and FHR tracings categories II and III were significantly associated with birth asphyxia.

Effect of glucose metabolism disorders on the short-term prognosis in neonates with asphyxia: a multicenter study in Hubei Province, China

OBJECTIVES

To study the effect of glucose metabolism disorders on the short-term prognosis in neonates with asphyxia.

METHODS

A retrospective analysis was performed on the medical data of the neonates with asphyxia who were admitted to 52 hospitals in Hubei Province of China from January to December, 2018 and had blood glucose data within 12 hours after birth. Their blood glucose data at 1, 2, 6, and 12 hours after birth (with an allowable time error of 0.5 hour) were recorded. According to the presence or absence of brain injury and/or death during hospitalization, the neonates were divided into a poor prognosis group with 693 neonates and a good prognosis group with 779 neonates. The two groups were compared in the incidence of glucose metabolism disorders within 12 hours after birth and short-term prognosis.

RESULTS

Compared with the good prognosis group, the poor prognosis group had a significantly higher proportion of neonates from secondary hospitals (48.5% vs 42.6%, P<0.05) or with severe asphyxia (19.8% vs 8.1%, P<0.05) or hypothermia therapy (4.8% vs 1.5%, P<0.05), as well as a significantly higher incidence rate of disorder of glucose metabolism (18.8% vs 12.5%, P<0.05). Compared with the good prognosis group, the poor prognosis group had a significantly higher incidence rate of disorder of glucose metabolism at 1, 2, and 6 hours after birth (P<0.05). The multivariate logistic regression analysis showed that recurrent hyperglycemia (adjusted odds ratio=2.380, 95% confidence interval: 1.275-4.442, P<0.05) was an independent risk factor for poor prognosis in neonates with asphyxia.

CONCLUSIONS

Recurrent hyperglycemia in neonates with asphyxia may suggest poor short-term prognosis, and it is necessary to strengthen the early monitoring and management of the nervous system in such neonates.

Stem Cell Therapy for Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of Preclinical Studies

Neonatal hypoxic-ischemic encephalopathy (HIE) is an important cause of mortality and morbidity in the perinatal period. This condition results from a period of ischemia and hypoxia to the brain of neonates, leading to several disorders that profoundly affect the daily life of patients and their families. Currently, therapeutic hypothermia (TH) is the standard of care in developing countries; however, TH is not always effective, especially in severe cases of HIE. Addressing this concern, several preclinical studies assessed the potential of stem cell therapy (SCT) for HIE. With this systematic review, we gathered information included in 58 preclinical studies from the last decade, focusing on the ones using stem cells isolated from the umbilical cord blood, umbilical cord tissue, placenta, and bone marrow. Outstandingly, about 80% of these studies reported a significant improvement of cognitive and/or sensorimotor function, as well as decreased brain damage. These results show the potential of SCT for HIE and the possibility of this therapy, in combination with TH, becoming the next therapeutic approach for HIE. Nonetheless, few preclinical studies assessed the combination of TH and SCT for HIE, and the existent studies show some contradictory results, revealing the need to further explore this line of research.

Inhibition of Colony Stimulating Factor 1 Receptor Suppresses Neuroinflammation and Neonatal Hypoxic-Ischemic Brain Injury

Hypoxic-ischemic (HI) brain injury is a major cause of neonatal death or lifetime disability without widely accepted effective pharmacological treatments. It has been shown that the survival of microglia requires colony-stimulating factor 1 receptor (CSF1R) signaling and microglia participate in neonatal HI brain injury. We therefore hypothesize that microglia depletion during a HI insult period could reduce immature brain injury. In this study, CD1 mouse pups were treated with a CSF1R inhibitor (PLX3397, 25 mg/kg/daily) or a vehicle from postnatal day 4 to day 11 (P4-11), and over 90% of total brain microglia were deleted at P9. Unilateral hemisphere HI injury was induced at P9 by permanently ligating the left common carotid arteries and exposing the pups to 10% oxygen for 30 min to produce moderate left hemisphere injury. We found that the PLX3397 treatment reduced HI brain injury by 46.4%, as evaluated by the percentage of brain infarction at 48 h after HI. Furthermore, CSF1R inhibition suppressed the infiltration of neutrophils (69.7% reduction, p = 0.038), macrophages (77.4% reduction, p = 0.009), and T cells (72.9% reduction, p = 0.008) to the brain, the production of cytokines and chemokines (such as CCL12, CCL6, CCL21, CCL22, CCL19, IL7, CD14, and WISP-1), and reduced neuronal apoptosis as indicated by active caspase-3 labeled cells at 48 h after HI (615.20 ± 156.84/mm² vs. 1,205.00 ± 99.15/mm², p = 0.013). Our results suggest that CSF1R inhibition suppresses neuroinflammation and neonatal brain injury after acute cerebral hypoxia-ischemia in neonatal mice.