Hypoxic-ischemic brain injury in the term infant-current concepts

Early Morbidities of Hypoxia-Ischemic Encephalopathy in Term Neonates With a Resistive Index as a Prognostic Indicator

Background Acidosis, hypoxemia, and hypercarbia are symptoms of a syndrome known as perinatal asphyxia that occurs during the first and second stages of labor and shortly after delivery due to poor gas exchange. The Doppler technique is a non-invasive way to assess the risk of neurodevelopment damage in hypoxic-ischemic encephalopathy (HIE) that may be done at the patient's bedside without disturbing them. The study aims to evaluate cranial ultrasound findings in HIE and investigate the role of resistive index (RI) values assessed by color Doppler transcranial ultrasonography in predicting early morbidities in neonates with HIE within 72 hours of life. Methodology Prospective observational research was carried out at the north Karnataka region's tertiary newborn critical care unit. The study included 54 infants with HIE in total. The male-to-female ratio was 1.7:1, with 34 (63%) male and 20 (37%) female newborns. Results About 32 instances had grade I HIE, 8 had grade II HIE, and 14 had grade III HIE. In 35 instances (64.81%), the RI was normal; in 19 cases (35.19%), it was abnormal. Increased periventricular density and cerebral parenchyma echo density were common Doppler ultrasonography findings. Roughly 93% of people survived, and 7% of people died from HIE. Seizures (12.96%) and acute renal damage (33.33%) were the most frequent consequences. Conclusion In instances of HIE, the RI was revealed to be a favorable predictive indicator for newborn prognosis. Counseling and educating parents about early morbidities, anticipated long-term consequences, and the need for follow-up will all benefit from it. Additionally, color Doppler is a practical and secure diagnostic method for determining a newborn's level of HIE.

N-Acetyl Serotonin Provides Neuroprotective Effects by Inhibiting Ferroptosis in the Neonatal Rat Hippocampus Following Hypoxic Brain Injury

Hypoxic-ischemic encephalopathy is the main cause of infant brain damage, perinatal death, and chronic neonatal disability worldwide. Ferroptosis is a new form of cell death that is closely related to hypoxia-induced brain damage. N-Acetyl serotonin (NAS) exerts neuroprotective effects, but its effects and underlying mechanisms in hypoxia-induced brain damage remain unclear. In the present study, 5-day-old neonatal Sprague-Dawley rats were exposed to hypoxia for 7 days to establish a hypoxia model. Histochemical staining was used to measure the effects of hypoxia on the rat hippocampus. The hippocampal tissue in the hypoxia group showed significant atrophy. Hypoxia significantly increased the levels of prostaglandin-endoperoxide synthase 2 (PTGS2) and the iron metabolism-related protein transferrin receptor 1 (TfR1) and decreased the levels of glutathione peroxidase 4 (GPX4). These changes resulted in mitochondrial damage, causing neuronal ferroptosis in the hippocampus. More importantly, NAS may improve mitochondrial function and alleviate downstream ferroptosis and damage to the hippocampus following hypoxia. In conclusion, we found that NAS could suppress neuronal ferroptosis in the hippocampus following hypoxic brain injury. These discoveries highlight the potential use of NAS as a treatment for neuronal damage through the suppression of ferroptosis, suggesting new treatment strategies for hypoxia-induced brain damage.

Sex differences in neonatal brain injury and inflammation

Neonatal brain injury and associated inflammation is more common in males. There is a well-recognised difference in incidence and outcome of neonatal encephalopathy according to sex with a pronounced male disadvantage. Neurodevelopmental differences manifest from an early age in infancy with females having a lower incidence of developmental delay and learning difficulties in comparison with males and male sex has consistently been identified as a risk factor for cerebral palsy in epidemiological studies. Important neurobiological differences exist between the sexes with respect to neuronal injury which are especially pronounced in preterm neonates. There are many potential reasons for these sex differences including genetic, immunological and hormonal differences but there are limited studies of neonatal immune response. Animal models with induced neonatal hypoxia have shown various sex differences including an upregulated immune response and increased microglial activation in males. Male sex is recognized to be a risk factor for neonatal hypoxic ischemic encephalopathy (HIE) during the perinatal period and this review discusses in detail the sex differences in brain injury in preterm and term neonates and some of the potential new therapies with possible sex affects.

Mild hypoxia-induced structural and functional changes of the hippocampal network

Hypoxia causes structural and functional changes in several brain regions, including the oxygen-concentration-sensitive hippocampus. We investigated the consequences of mild short-term hypoxia on rat hippocampus in vivo. The hypoxic group was treated with 16% O2 for 1 h, and the control group with 21% O2. Using a combination of Gallyas silver impregnation histochemistry revealing damaged neurons and interneuron-specific immunohistochemistry, we found that somatostatin-expressing inhibitory neurons in the hilus were injured. We used 32-channel silicon probe arrays to record network oscillations and unit activity from the hippocampal layers under anaesthesia. There were no changes in the frequency power of slow, theta, beta, or gamma bands, but we found a significant increase in the frequency of slow oscillation (2.1-2.2 Hz) at 16% O2 compared to 21% O2. In the hilus region, the firing frequency of unidentified interneurons decreased. In the CA3 region, the firing frequency of some unidentified interneurons decreased while the activity of other interneurons increased. The activity of pyramidal cells increased both in the CA1 and CA3 regions. In addition, the regularity of CA1, CA3 pyramidal cells' and CA3 type II and hilar interneuron activity has significantly changed in hypoxic conditions. In summary, a low O2 environment caused profound changes in the state of hippocampal excitatory and inhibitory neurons and network activity, indicating potential changes in information processing caused by mild short-term hypoxia.

Effects of prenatal hypoxia-ischemia on male rat periaqueductal gray matter: Hyperalgesia, astrogliosis and nitrergic system impairment

Prenatal hypoxic-ischemic insult (HI) may lead to a variety of neurological consequences that may persist throughout adulthood. In the most severe cases, HI is known to increase pain sensitivity which profoundly impacts quality of life. Periaqueductal gray matter (PAG) is a relevant region of the descending pain pathway and its function may be modulated by a complex network that includes nitrergic neurons and glial response, among other factors. Astrocytes, central players in pain modulation, are known to respond to HI by inducing hyperplasia, hypertrophy and increasing the number of their processes and the staining of glial fibrillary acidic protein (GFAP). In this work we investigated the effects of prenatal HI on touch and pain sensitivity, besides the distribution of the neuronal isoform of Nitric Oxide Synthase (nNOS) and GFAP in the PAG of young and adult male rats. At 18 days of gestation, rats had their uterine arteries clamped for 45 min (HI group). SHAM-operated animals were also generated (SHAM group). At post-natal day 30 (P30) or 90 (P90), the offspring was submitted to the behavioral tests of Von Frey and formalin or histological processing to perform immunohistochemistry for nNOS and GFAP. Although there was no significant difference between the groups concerning touch sensitivity, we observed an increase in pain sensitivity in HI P30 and HI P90. The number of nNOS + cells was reduced in HI adult animals in dlPAG and vlPAG. GFAP immunostaining was increased in HI P90 in dlPAG and dmPAG. Our results demonstrated for the first time an increase in pain sensitivity as a consequence of prenatal HI in an animal model. It reinforces the relevance of this model to mimic the effects of prenatal HI, as hyperalgesia.

Multi-layer perceptron classification & quantification of neuronal survival in hypoxic-ischemic brain image slices using a novel gradient direction, grey level co-occurrence matrix image training

Hypoxic ischemic encephalopathy (HIE) is a major global cause of neonatal death and lifelong disability. Large animal translational studies of hypoxic ischemic brain injury, such as those conducted in fetal sheep, have and continue to play a key role in furthering our understanding of the cellular and molecular mechanisms of injury and developing new treatment strategies for clinical translation. At present, the quantification of neurons in histological images consists of slow, manually intensive morphological assessment, requiring many repeats by an expert, which can prove to be time-consuming and prone to human error. Hence, there is an urgent need to automate the neuron classification and quantification process. In this article, we present a 'Gradient Direction, Grey level Co-occurrence Matrix' (GD-GLCM) image training method which outperforms and simplifies the standard training methodology using texture analysis to cell-classification. This is achieved by determining the Grey level Co-occurrence Matrix of the gradient direction of a cell image followed by direct passing to a classifier in the form of a Multilayer Perceptron (MLP). Hence, avoiding all texture feature computation steps. The proposed MLP is trained on both healthy and dying neurons that are manually identified by an expert and validated on unseen hypoxic-ischemic brain slice images from the fetal sheep in utero model. We compared the performance of our classifier using the gradient magnitude dataset as well as the gradient direction dataset. We also compare the performance of a perceptron, a 1-layer MLP, and a 2-layer MLP to each other. We demonstrate here a way of accurately identifying both healthy and dying cortical neurons obtained from brain slice images of the fetal sheep model under global hypoxia to high precision by identifying the most minimised MLP architecture, minimised input space (GLCM size) and minimised training data (GLCM representations) to achieve the highest performance over the standard methodology.

The Usefulness of Serum Brain Damage Biomarkers in Detection and Evaluation of Hypoxic Ischemic Encephalopathy in Calves with Perinatal Asphyxia

The purpose of the present study was to determine hypoxic brain damage in calves with perinatal asphyxia using brain-specific damage biomarkers. Ten healthy and 25 calves with perinatal asphyxia were enrolled in the study. Clinical examination, neurological status score, and laboratory analysis were performed at admission, 24, 48, and 72 h. Serum concentrations of ubiquitin carboxy-terminal hydrolysis 1 (UCHL1), calcium-binding protein B (S100B), adrenomodullin (ADM), activitin A (ACTA), neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP) and creatine kinase-brain (CK-B) were measured. Histopathological and immunohistochemical examinations of the brain tissue were performed in 13 nonsurvivor calves. The neurological status score of the calves with asphyxia was significantly (p < 0.05) lower. Mix metabolic-respiratory acidosis and hypoxemia were detected in calves with asphyxia. Serum UCHL1 and S100B were significantly (p < 0.05) increased, and NSE, ACTA, ADM, and CK-B were decreased (p < 0.05) in calves with asphyxia. Histopathological and immunohistochemical examinations confirmed the development of mild to severe hypoxic-ischemic encephalopathy. In conclusion, asphyxia and hypoxemia caused hypoxic-ischemic encephalopathy in perinatal calves. UCHL1 and S100B concentrations were found to be useful markers for the determination of hypoxic-ischemic encephalopathy in calves with perinatal asphyxia. Neurological status scores and some blood gas parameters were helpful in mortality prediction.

Resveratrol and Some of Its Derivatives as Promising Prophylactic Treatments for Neonatal Hypoxia-Ischemia

Due to the rate of occurrence of neonatal hypoxia-ischemia, its neuronal sequelae, and the lack of effective therapies, the development of new neuroprotective strategies is required. Polyphenols (including resveratrol) are molecules whose anti-apoptotic, anti-inflammatory, and anti-oxidative properties could be effective against the damage induced by neonatal hypoxia-ischemia. In this review article, very recent data concerning the neuroprotective role of polyphenols and the mechanisms at play are detailed, including a boost in brain energy metabolism. The results obtained with innovative approaches, such as maternal supplementation at nutritional doses, suggest that polyphenols could be a promising prophylactic treatment for neonatal hypoxia-ischemia.

Periventricular- intraventricular hemorrhage in the premature infant- A historical perspective

The objective of this chapter is to trace the evolution of intraventricular hemorrhage in the premature infant highlighting the importance of the germinal matrix, a critical role for cerebral blood flow changes in the genesis of hemorrhage, clinical factors that increase the bleeding risk, and potential preventative strategies. In 1976, neuropathological studies demonstrated capillary rupture within the germinal matrix as the precursor of hemorrhage. In 1980, introduction of cranial ultrasound facilitated diagnosis of intraventricular hemorrhage. In 1979, loss of cerebral autoregulation in sick newborn infants was demonstrated. In the 1980's, studies demonstrated the importance of intravascular factors in provoking hemorrhage. In 1983, the association of cerebral blood flow velocity fluctuations and subsequent hemorrhage was demonstrated. In 1994, antenatal steroids use to accelerate lung development was recommended. This was associated with an unanticipated reduction in hemorrhage. In the mid 1990's early indomethacin administration was associated with a reduction of severe hemorrhage.

Re-evaluation of medical findings in alleged shaken baby syndrome and abusive head trauma in Norwegian courts fails to support abuse diagnoses

AIM

The criteria for diagnosing abusive head trauma (AHT) are not well defined and this condition might be diagnosed on failing premises. Our aim was to review criminal AHT cases in Norwegian courts by scrutinising the underlying medical documentation.

METHODS

Cases were identified in the data registry for Norwegian courts from 2004 to 2015. Documentation was obtained from relevant health institutions. The medical co-authors first made independent evaluations of the documentation for each child, followed by a consensus evaluation.

RESULTS

A total of 17 children (11 boys) were identified, all diagnosed as AHT by court appointed experts, 15 were infants (mean age 2.6 months). A high proportion (41.2%) was born to immigrant parents and 31.3% were premature. The medical findings could be explained by alternative diagnoses in 16 of the 17 children; 8 boys (7 infants - mean age 2.9 months) had clinical and radiological characteristics compatible with external hydrocephalus complicated by chronic subdural haematoma. Six children (five infants with mean age 2.1 months) had a female preponderance and findings compatible with hypoxic ischaemic insults.

CONCLUSION

The medical condition in most children had not necessarily been caused by shaking or direct impact, as was originally concluded by the court experts.

Profiling Temporal Changes of the Pineal Transcriptomes at Single Cell Level Upon Neonatal HIBD

Neonatal hypoxic-ischemic brain damage (HIBD) often results in various neurological deficits. Among them, a common, yet often neglected, symptom is circadian rhythm disorders. Previous studies revealed that the occurrence of cysts in the pineal gland, an organ known to regulate circadian rhythm, is associated with circadian problems in children with HIBD. However, the underlying mechanisms of pineal dependent dysfunctions post HIBD remain largely elusive. Here, by performing 10x single cell RNA sequencing, we firstly molecularly identified distinct pineal cell types and explored their transcriptome changes at single cell level at 24 and 72 h post neonatal HIBD. Bioinformatic analysis of cell prioritization showed that both subtypes of pinealocytes, the predominant component of the pineal gland, were mostly affected. We then went further to investigate how distinct pineal cell types responded to neonatal HIBD. Within pinealocytes, we revealed a molecularly defined β to α subtype conversion induced by neonatal HIBD. Within astrocytes, we discovered that all three subtypes responded to neonatal HIBD, with differential expression of reactive astrocytes markers. Two subtypes of microglia cells were both activated by HIBD, marked by up-regulation of Ccl3. Notably, microglia cells showed substantial reduction at 72 h post HIBD. Further investigation revealed that pyroptosis preferentially occurred in pineal microglia through NLRP3-Caspase-1-GSDMD signaling pathway. Taken together, our results delineated temporal changes of molecular and cellular events occurring in the pineal gland following neonatal HIBD. By revealing pyroptosis in the pineal gland, our study also provided potential therapeutic targets for preventing extravasation of pineal pathology and thus improving circadian rhythm dysfunction in neonates with HIBD.

Value of cranial ultrasound at initiation of therapeutic hypothermia for neonatal encephalopathy

OBJECTIVE

There is variation in the clinical practice for the use of cranial ultrasound (cUS) at the time of initiation of therapeutic hypothermia (TH) for neonatal encephalopathy. The role of cUS in selecting patients who may benefit from TH or excluding those where TH may impose risk is unknown.

STUDY DESIGN

A retrospective study was conducted on infants who received TH at a single tertiary center. Findings from cUS at initiation of TH were compared to findings from MRI following the completion of TH.

RESULTS

One hundred and eight infants were studied. Of the 55 with abnormalities on early cUS, 50 did not have corresponding MRI abnormalities. In contrast, 16 infants had some degree of intracranial hemorrhage detected on their MRI that was not noted on earlier cUS.

CONCLUSIONS

This study challenges whether cUS is an essential universal screening tool prior to the commencement of TH.

Outcomes of neonatal hypoxic-ischaemic encephalopathy in centres with and without active therapeutic hypothermia: a nationwide propensity score-matched analysis

OBJECTIVE

Therapeutic hypothermia (TH) for neonatal hypoxic-ischaemic encephalopathy (HIE), delivered mainly in tertiary cooling centres (CCs), reduces mortality and neurodisability. It is unknown if birth in a non-cooling centre (non-CC), without active TH, impacts short-term outcomes.

DESIGN

Retrospective cohort study using National Neonatal Research Database and propensity score-matching.

SETTING

UK neonatal units.

PATIENTS

Infants ≥36 weeks gestational age with moderate or severe HIE admitted 2011-2016.

INTERVENTIONS

Birth in non-CC compared with CC.

MAIN OUTCOME MEASURES

Primary outcome was survival to discharge without recorded seizures. Secondary outcomes were recorded seizures, mortality and temperature on arrival at CCs following transfer.

RESULTS

5059 infants were included with 2364 (46.7%) born in non-CCs. Birth in a CC was associated with improved survival without seizures (35.1% vs 31.8%; OR 1.15, 95% CI 1.02 to 1.31; p=0.02), fewer seizures (60.7% vs 64.6%; OR 0.84, 95% CI 0.75 to 0.95, p=0.007) and similar mortality (15.8% vs 14.4%; OR 1.11, 95% CI 0.93 to 1.31, p=0.20) compared with birth in a non-CC. Matched infants from level 2 centres only had similar results, and birth in CCs was associated with greater seizure-free survival compared with non-CCs. Following transfer from a non-CC to a CC (n=2027), 1362 (67.1%) infants arrived with a recorded optimal therapeutic temperature but only 259 (12.7%) of these arrived within 6 hours of birth.

CONCLUSIONS

Almost half of UK infants with HIE were born in a non-CC, which was associated with suboptimal hypothermic treatment and reduced seizure-free survival. Provision of active TH in non-CC hospitals prior to upward transfer warrants consideration.

Sildenafil-Mediated Neuroprotection from Adult to Neonatal Brain Injury: Evidence, Mechanisms, and Future Translation

Cerebral stroke, traumatic brain injury, and hypoxic ischemic encephalopathy are among the most frequently occurring brain injuries. A complex pathogenesis, characterized by a synergistic interaction between alterations of the cerebrovascular system, cell death, and inflammation, is at the basis of the brain damage that leads to behavioral and neurodevelopmental disabilities in affected subjects. Sildenafil is a selective inhibitor of the enzyme phosphodiesterase 5 (PDE5) that is able to cross the blood-brain barrier. Preclinical data suggest that sildenafil may be a good candidate for the prevention or repair of brain injury in both adults and neonates. The aim of this review is to summarize the evidence supporting the neuroprotective action of sildenafil and discuss the possible benefits of the association of sildenafil with current therapeutic strategies.

Randomized trial of oxygen weaning strategies following chest compressions during neonatal resuscitation

BACKGROUND

The Neonatal Resuscitation Program (NRP) recommends using 100% O2 during chest compressions and adjusting FiO2 based on SpO2 after return of spontaneous circulation (ROSC). The optimal strategy for adjusting FiO2 is not known.

METHODS

Twenty-five near-term lambs asphyxiated by umbilical cord occlusion to cardiac arrest were resuscitated per NRP. Following ROSC, lambs were randomized to gradual decrease versus abrupt wean to 21% O2 followed by FiO2 titration to achieve NRP SpO2 targets. Carotid blood flow and blood gases were monitored.

RESULTS

Three minutes after ROSC, PaO2 was 229 ± 32 mmHg in gradual wean group compared to 57 ± 13 following abrupt wean to 21% O2 (p < 0.001). PaO2 remained high in the gradual wean group at 10 min after ROSC (110 ± 10 vs. 67 ± 12, p < 0.01) despite similar FiO2 (~0.3) in both groups. Cerebral O2 delivery (C-DO2) was higher above physiological range following ROSC with gradual wean (p < 0.05). Lower blood oxidized/reduced glutathione ratio (suggesting less oxidative stress) was observed with abrupt wean.

CONCLUSION

Weaning FiO2 abruptly to 0.21 with adjustment based on SpO2 prevents surge in PaO2 and C-DO2 and minimizes oxidative stress compared to gradual weaning from 100% O2 following ROSC. Clinical trials with neurodevelopmental outcomes comparing post-ROSC FiO2 weaning strategies are warranted.

IMPACT

In a lamb model of perinatal asphyxial cardiac arrest, abrupt weaning of inspired oxygen to 21% prevents excessive oxygen delivery to the brain and oxidative stress compared to gradual weaning from 100% oxygen following return of spontaneous circulation. Clinical studies assessing neurodevelopmental outcomes comparing abrupt and gradual weaning of inspired oxygen after recovery from neonatal asphyxial arrest are warranted.

Gray-scale ultrasound findings of hypoxic-ischemic injury in term infants

Brain ultrasound has become a critical tool for bedside screening and monitoring of hypoxic-ischemic injury in infants. Transfontanellar ultrasound in infants allows delineation of anatomical structures of the brain and posterior fossa. The technique's low cost, lack of ionizing radiation and repeatability make it a popular alternative to magnetic resonance imaging. The published literature on interpreting hypoxic-ischemic injury on brain ultrasound is wide and varied, yet diagnostic challenges remain when detecting subtle or diffuse changes. This pictorial essay summarizes and illustrates the spectrum of sonographic findings of hypoxic-ischemic injuries in term infants.

Maternal depression during pregnancy alters infant subcortical and midbrain volumes

BACKGROUND

Maternal depression in pregnancy increases the risk for adverse neurodevelopmental outcomes in the offspring. The reason for this is unknown, however, one plausible mechanism may include the impact of maternal antenatal depression on infant brain. Nevertheless, relatively few studies have examined the brain anatomy of infants born to clinically diagnosed mothers.

METHODS

A legacy magnetic resonance imaging (MRI) dataset was used to compare regional brain volumes in 3-to-6-month-old infants born to women with a clinically confirmed diagnosis of major depressive disorder (MDD) during pregnancy (n = 31) and a reference sample of infants born to women without a current or past psychiatric diagnosis (n = 33). A method designed for analysis of low-resolution scans enabled examination of subcortical and midbrain regions previously found to be sensitive to the parent-child environment.

RESULTS

Compared with infants of non-depressed mothers, infants exposed to maternal antenatal depression had significantly larger subcortical grey matter volumes and smaller midbrain volumes. There was no association between gestational medication exposure and the infant regional brain volumes examined in our sample.

LIMITATIONS

Our scanning approach did not allow for an examination of fine-grained structural differences, and without repeated measures of brain volume, it is unknown whether the direction of reported associations are dependent on developmental stage.

CONCLUSIONS

Maternal antenatal depression is associated with an alteration in infant brain anatomy in early postnatal life; and that this is not accounted for by medication exposure. However, our study cannot address whether anatomical differences impact on future outcomes of the offspring.

Restricted diffusion in the corpus callosum: A neuroradiological marker in hypoxic-ischemic encephalopathy

Background:

Restricted diffusion within the splenium of the corpus callosum has been described by other authors in various conditions, however, restricted diffusion in the entire corpus callosum or isolated involvement of the splenium, genu, or body has been infrequently reported on magnetic resonance imaging (MRI) in neonatal hypoxic–ischemic encephalopathy. We report a series of cases showing different patterns of involvement.

Methods and Materials:

Perinatal imaging with MRI including diffusion-weighted imaging was performed in 40 neonates with hypoxic–ischemic encephalopathy, including 11 premature neonates. Sixteen out of 40 patients demonstrated restricted diffusion within the corpus callosum. Out of 16 patients, 9 showed restricted diffusion in the entire corpus callosum, 4 had isolated splenium involvement, 2 had body and splenium signal abnormality, and 1 showed diffusion restriction only in the genu.

Conclusions:

Changes in the corpus callosum were also associated with more severe clinical presentation of encephalopathy. Restricted diffusion within the corpus callosum in infants with hypoxic–ischemic encephalopathy is often associated with extensive brain injury and appears to be an early neuroradiologic marker of adverse neurologic outcome.

Neuroprotective Potential of Limonene and Limonene Containing Natural Products

Limonene is a monoterpene confined to the family of Rutaceae, showing several biological properties such as antioxidant, anti-inflammatory, anticancer, antinociceptive and gastroprotective characteristics. Recently, there is notable interest in investigating the pharmacological effects of limonene in various chronic diseases due to its mitigating effect on oxidative stress and inflammation and regulating apoptotic cell death. There are several available studies demonstrating the neuroprotective role of limonene in neurodegenerative diseases, including Alzheimer's disease, multiple sclerosis, epilepsy, anxiety, and stroke. The high abundance of limonene in nature, its safety profile, and various mechanisms of action make this monoterpene a favorable molecule to be developed as a nutraceutical for preventive purposes and as an alternative agent or adjuvant to modern therapeutic drugs in curbing the onset and progression of neurodegenerative diseases. This manuscript presents a comprehensive review of the available scientific literature discussing the pharmacological activities of limonene or plant products containing limonene which attribute to the protective and therapeutic ability in neurodegenerative disorders. This review has been compiled based on the existing published articles confined to limonene or limonene-containing natural products investigated for their neurotherapeutic or neuroprotective potential. All the articles available in English or the abstract in English were extracted from different databases that offer an access to diverse journals. These databases are PubMed, Scopus, Google Scholar, and Science Direct. Collectively, this review emphasizes the neuroprotective potential of limonene against neurodegenerative and other neuroinflammatory diseases. The available data are indicative of the nutritional use of products containing limonene and the pharmacological actions and mechanisms of limonene and may direct future preclinical and clinical studies for the development of limonene as an alternative or complementary phytomedicine. The pharmacophore can also provide a blueprint for further drug discovery using numerous drug discovery tools.

Neferine Protects against Hypoxic-Ischemic Brain Damage in Neonatal Rats by Suppressing NLRP3-Mediated Inflammasome Activation

Hypoxic-ischemic encephalopathy (HIE) is recognized as the main cause of neonatal death, and efficient treatment strategies remain limited. Given the prevalence of HIE and the associated fatality, further studies on its pathogenesis are warranted. Oxidative stress and neuroinflammatory injury are two important factors leading to brain tissue injury and nerve cell loss in HIE. Neferine, an alkaloid extracted from lotus seed embryo, exerts considerable effects against several diseases such as cancers and myocardial injury. In this study, we demonstrated the neuroprotective effect of neferine on HIE and hypothesized that it involves the inhibition of neuronal pyroptosis, thereby ameliorating neurological inflammation and oxidative stress. We demonstrated that the mRNA levels of proteins associated with pyroptosis including caspase-1, the caspase adaptor ASC, gasdermin D, interleukin- (IL-) 18, IL-1β, and some inflammatory factors were significantly increased in neonatal HIBD model rats compared to those in the control group. The increase in these factors was significantly suppressed by treatment with neferine. We stimulated PC12 cells with CoCl2 to induce neuronal HIBD in vitro and investigated the relationship between neferine and pyroptosis by altering the expression of the NLRP3 inflammasome. The overexpression of NLRP3 partially reversed the neuroprotective effect of neferine on HIBD, whereas NLRP3 knockdown further inhibited caspase-1 activation and IL-1β and IL18 expression. In addition, simultaneous alteration of NLRP3 expression induced changes in intracellular oxidative stress levels after HIBD. These findings indicate that neferine ameliorates neuroinflammation and oxidative stress injury by inhibiting pyroptosis after HIBD. Our study provides valuable information for future studies on neferine with respect to neuroinflammation and pyroptosis.

Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors

Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A₁ and A_2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.

Neuroprotective role of lactate in rat neonatal hypoxia-ischemia

Hypoxic-ischemic (HI) encephalopathy remains a major cause of perinatal mortality and chronic disability in newborns worldwide (1-6 for 1000 births). The only current clinical treatment is hypothermia, which is efficient for less than 60% of babies. Mainly considered as a waste product in the past, lactate, in addition to glucose, is increasingly admitted as a supplementary fuel for neurons and, more recently, as a signaling molecule in the brain. Our aim was to investigate the neuroprotective effect of lactate in a neonatal (seven day old) rat model of hypoxia-ischemia. Pups received intra-peritoneal injection(s) of lactate (40 μmol). Size and apparent diffusion coefficients of brain lesions were assessed by magnetic resonance diffusion-weighted imaging. Oxiblot analyses and long-term behavioral studies were also conducted. A single lactate injection induced a 30% reduction in brain lesion volume, indicating a rapid and efficient neuroprotective effect. When oxamate, a lactate dehydrogenase inhibitor, was co-injected with lactate, the neuroprotection was completely abolished, highlighting the role of lactate metabolism in this protection. After three lactate injections (one per day), pups presented the smallest brain lesion volume and a complete recovery of neurological reflexes, sensorimotor capacities and long-term memory, demonstrating that lactate administration is a promising therapy for neonatal HI insult.

Lactate Administration Reduces Brain Injury and Ameliorates Behavioral Outcomes Following Neonatal Hypoxia-Ischemia

Neonatal hypoxic-ischemic encephalopathy is a major cause of mortality and disability in newborns and the only standard approach for treating this condition is therapeutic hypothermia, which shows some limitations. Thus, putative neuroprotective agents have been tested in animal models. The present study evaluated the administration of lactate, a potential energy substrate of the central nervous system (CNS) in an animal model of hypoxia-ischemia (HI), that mimics in neonatal rats the brain damage observed in human newborns. Seven-day-old (P7) male and female Wistar rats underwent permanent common right carotid occlusion combined with an exposition to a hypoxic atmosphere (8% oxygen) for 60 min. Animals were assigned to four experimental groups: HI, HI + LAC, SHAM, SHAM + LAC. Lactate was administered intraperitoneally 30 min and 2 h after hypoxia in HI + LAC and SHAM + LAC groups. HI and SHAM groups received vehicle at the same time points. The volume of brain lesion was evaluated in P9. Animals underwent behavioral assessments: negative geotaxis, righting reflex (P8 and P14), and cylinder test (P20). Lactate administration reduced the volume of brain lesion and improved behavioral parameters after HI in both sexes. Thus, lactate administration could be a neuroprotective strategy for the treatment of neonatal HI, a disorder still affecting a significant percentage of human newborns.

Cooling and immunomodulation for treating hypoxic-ischemic brain injury

Therapeutic hypothermia is now well established to partially reduce disability in term and near-term infants with moderate-severe hypoxic-ischemic encephalopathy. Preclinical and clinical studies have confirmed that current protocols for therapeutic hypothermia are near optimal. The challenge is now to identify complementary therapies that can further improve outcomes, in combination with therapeutic hypothermia. Overall, anti-excitatory and anti-apoptotic agents have shown variable or even no benefit in combination with hypothermia, suggesting overlapping mechanisms of neuroprotection. Inflammation appears to play a critical role in the pathogenesis of injury in the neonatal brain, and thus, there is potential for drugs with immunomodulatory properties that target inflammation to be used as a therapy in neonates. In this review, we examine the evidence for neuroprotection with immunomodulation after hypoxia-ischemia. For example, stem cell therapy can reduce inflammation, increase cell survival, and promote cell maturation and repair. There are also encouraging preclinical data from small animals suggesting that stem cell therapy can augment hypothermic neuroprotection. However, there is conflicting evidence, and rigorous testing in translational animal models is now needed.

Long-Term Effects of Hypoxia-Reoxygenation on Thioredoxins in Rat Central Nervous System

BACKGROUND

Oxidative stress induced by the oxidative pathway dysregulation following ischemia/ reperfusion has been proposed as an important cause of neuronal death and brain damage. The proteins of the thioredoxin (Trx) family are crucial mediators of protein function regulating the intracellular hydrogen peroxide levels and redox-sensitive post-translational protein changes.

AIM

To analyze the expression and distribution of fourteen members of the Trx family, potentially essential for the regeneration upon long-term brain damage, in a perinatal hypoxia-ischemia rat model induced by common carotid artery ligation.

METHODS

The right common carotid artery (CCA) was exposed by an incision on the right side of the neck, isolated from nerve and vein, and permanently ligated. Sham-surgery rats underwent right CCA surgical exposure but no ligation. Euthanasia was administered to all rats at 30, 60, and 90 days of age. Protein expression and distribution of fourteen members of the Trx family and related proteins (Grx1, Grx2, Grx3, Grx5, Prx1, Prx2, Prx3, Prx4, Prx5, Prx6, Trx1, Trx2, TrxR1, TrxR2) was examined in the most hypoxia susceptible rat brain areas, namely, cerebellum, corpus striatum, and the hippocampus.

RESULTS

The thioredoxin proteins displayed a complex, cell-type, and tissue-specific expression pattern following ischemia/reperfusion. Even 60 days after ischemia/reperfusion, Western blot analysis showed a persistent expression of Trx1 and Grx2 in several brain areas.

CONCLUSION

The Trx family of proteins might contribute to long-term survival and recovery supporting their therapeutic use to curtail ischemic brain oxidative damage following an ischemia/reperfusion insult. Characterization of ischemia/reperfusion oxidative brain damage and analysis of the involved mechanisms are required to understand the underneath processes triggered by ischemia/reperfusion and to what extent and in what way thioredoxins contribute to recovery from brain hypoxic stress.

Cortical ischaemic patterns in term partial-prolonged hypoxic-ischaemic injury-the inter-arterial watershed demonstrated through atrophy, ulegyria and signal change on delayed MRI scans in children with cerebral palsy

The inter-arterial watershed zone in neonates is a geographic area without discernible anatomic boundaries and difficult to demarcate and usually not featured in atlases. Schematics currently used to depict the areas are not based on any prior anatomic mapping, compared to adults.Magnetic resonance imaging (MRI) of neonates in the acute to subacute phase with suspected hypoxic-ischaemic injury (HII) can demonstrate signal abnormality and restricted diffusion in the cortical and subcortical parenchyma of the watershed regions.In the chronic stage of partial-prolonged hypoxic-ischaemic injury, atrophy and ulegyria can make the watershed zone more conspicuous as a region. Our aim is to use images extracted from a sizable medicolegal database (approximately 2000 cases), of delayed MRI scans in children with cerebral palsy, to demonstrate the watershed region.To achieve this, we have selected cases diagnosed on imaging as having sustained a term pattern of partial-prolonged HII affecting the hemispheric cortex, based on the presence of bilateral, symmetric atrophy with ulegyria. From these, we have identified those patients demonstrating injury along the whole watershed continuum as well as those demonstrating selective anterior or posterior watershed predominant injury for demonstration.Recognition of this zone is essential for diagnosing partial-prolonged hypoxic-ischaemic injury sustained in term neonates. The images presented in this pictorial review provide a template for identifying the cortical watershed distribution when there is milder regional (anterior, parasagittal, peri-Sylvian and posterior) watershed injury and for more severe injury where multiple regions are injured in combination or as a continuum.

Applications of advanced signal processing and machine learning in the neonatal hypoxic-ischemic electroencephalogram

Perinatal hypoxic-ischemic-encephalopathy significantly contributes to neonatal death and life-long disability such as cerebral palsy. Advances in signal processing and machine learning have provided the research community with an opportunity to develop automated real-time identification techniques to detect the signs of hypoxic-ischemic-encephalopathy in larger electroencephalography/amplitude-integrated electroencephalography data sets more easily. This review details the recent achievements, performed by a number of prominent research groups across the world, in the automatic identification and classification of hypoxic-ischemic epileptiform neonatal seizures using advanced signal processing and machine learning techniques. This review also addresses the clinical challenges that current automated techniques face in order to be fully utilized by clinicians, and highlights the importance of upgrading the current clinical bedside sampling frequencies to higher sampling rates in order to provide better hypoxic-ischemic biomarker detection frameworks. Additionally, the article highlights that current clinical automated epileptiform detection strategies for human neonates have been only concerned with seizure detection after the therapeutic latent phase of injury. Whereas recent animal studies have demonstrated that the latent phase of opportunity is critically important for early diagnosis of hypoxic-ischemic-encephalopathy electroencephalography biomarkers and although difficult, detection strategies could utilize biomarkers in the latent phase to also predict the onset of future seizures.

A single-nucleotide polymorphism induced alternative splicing in Tacr3 involves in hypoxic-ischemic brain damage

Single-nucleotide polymorphism (SNP) and Alternative splicing (AS) were found to be implicated in certain diseases, nevertheless, the contributions of mRNA SNPs and AS to pathogenesis in developing rat brains with hypoxic-ischemic encephalopathy (HIE) remained largely vague. Additionally, the disease associated with Tacr3 was normosmic congenital hypogonadotropic hypogonadism, while the relationship between HIE and Tacr3 remained largely elusive. The current study was designed to investigate the differentially expressed mRNAs and related SNPs as well as AS in neonatal rats subjected to HIE to identify if the exhibition of AS was associated with SNPs under pathological condition. Firstly, we used postnatal day 7 Sprague-Dawley rats to construct neonatal HIE model, and analyzed the expression profiles of SNP mRNA in hypoxic-ischemic (HI) and sham brains by using RNA sequencing. Then four genes, including Mdfic, Lpp, Bag3 and Tacr3, connecting with HIE and exhibiting SNPs and AS were identified by bioinformatics analysis. Moreover, combined with exonic splicing enhancer (ESE) and alternative splice site predictor (ASSP) analysis, we found that Tacr3 is associated specifically with HIE through 258547789 G > A SNP in inside the Alt First Exon and 258548573 G > A SNP in outside the Alt First Exon. Taken together, our study provides new evidence to understand the role of Tacr3 in HIE and it is possibly a potential target for the treatment of HIE in future clinic trial.

High-density diffuse optical tomography for imaging human brain function

This review describes the unique opportunities and challenges for noninvasive optical mapping of human brain function. Diffuse optical methods offer safe, portable, and radiation free alternatives to traditional technologies like positron emission tomography or functional magnetic resonance imaging (fMRI). Recent developments in high-density diffuse optical tomography (HD-DOT) have demonstrated capabilities for mapping human cortical brain function over an extended field of view with image quality approaching that of fMRI. In this review, we cover fundamental principles of the diffusion of near infrared light in biological tissue. We discuss the challenges involved in the HD-DOT system design and implementation that must be overcome to acquire the signal-to-noise necessary to measure and locate brain function at the depth of the cortex. We discuss strategies for validation of the sensitivity, specificity, and reliability of HD-DOT acquired maps of cortical brain function. We then provide a brief overview of some clinical applications of HD-DOT. Though diffuse optical measurements of neurophysiology have existed for several decades, tremendous opportunity remains to advance optical imaging of brain function to address a crucial niche in basic and clinical neuroscience: that of bedside and minimally constrained high fidelity imaging of brain function.

Lasting effects of general anesthetics on the brain in the young and elderly: "mixed picture" of neurotoxicity, neuroprotection and cognitive impairment

General anesthetics are commonly used in major surgery. To achieve the depth of anesthesia for surgery, patients are being subjected to a variety of general anesthetics, alone or in combination. It has been long held an illusory concept that the general anesthesia is entirely reversible and that the central nervous system is returned to its pristine state once the anesthetic agent is eliminated from the active site. However, studies indicate that perturbation of the normal functioning of these targets may result in long-lasting desirable or undesirable effects. This review focuses on the impact of general anesthetic exposure to the brain and summarizes the molecular and cellular mechanisms by which general anesthetics may induce long-lasting undesirable effects when exposed at the developing stage of the brain. The vulnerability of aging brain to general anesthetics, specifically in the context of cognitive disorders and Alzheimer’s disease pathogeneses are also discussed. Moreover, we will review emerging evidence regarding the neuroprotective property of xenon and anesthetic adjuvant dexmedetomidine in the immature and mature brains. In conclusion, “mixed picture” effects of general anesthetics should be well acknowledged and should be implemented into daily clinical practice for better patient outcome.

Neonatal brain injury and aberrant connectivity

Brain injury sustained during the neonatal period may disrupt development of critical structural and functional connectivity networks leading to subsequent neurodevelopmental impairment in affected children. These networks can be characterized using structural (via diffusion MRI) and functional (via resting state-functional MRI) neuroimaging techniques. Advances in neuroimaging have led to expanded application of these approaches to study term- and prematurely-born infants, providing improved understanding of cerebral development and the deleterious effects of early brain injury. Across both modalities, neuroimaging data are conducive to analyses ranging from characterization of individual white matter tracts and/or resting state networks through advanced 'connectome-style' approaches capable of identifying highly connected network hubs and investigating metrics of network topology such as modularity and small-worldness. We begin this review by summarizing the literature detailing structural and functional connectivity findings in healthy term and preterm infants without brain injury during the postnatal period, including discussion of early connectome development. We then detail common forms of brain injury in term- and prematurely-born infants. In this context, we next review the emerging body of literature detailing studies employing diffusion MRI, resting state-functional MRI and other complementary neuroimaging modalities to characterize structural and functional connectivity development in infants with brain injury. We conclude by reviewing technical challenges associated with neonatal neuroimaging, highlighting those most relevant to studying infants with brain injury and emphasizing the need for further targeted study in this high-risk population.

Morphological and immunohistochemical analysis of proteins CASPASE 3 and XIAP in rats subjected to cerebral ischemia and chronic alcoholism

PURPOSE

To evaluate histopathological and ultrastructural changes and expression of proteins related to apoptosis CASPASE 3 and XIAP after experimental induction of temporary focal cerebral ischemia (90 minutes) due to obstruction of the middle cerebral artery in alcoholism model.

METHODS

Forty adult Wistar rats were used, subdivided into 5 experimental groups: control group (C); Sham group (S); Ischemic group (I); Alcoholic group (A); and Ischemic and Alcoholized group (I+A): animals submitted to the same treatment of group A and after four weeks were submitted to focal cerebral ischemia during 90 minutes, followed by reperfusion of 48 hours. Were processed for histopathological analysis and immunohistochemistry (for the protein expression of CASPASE -3 and XIAP).

RESULTS

Greater histopathological changes were observed in the animals of groups I and I+A in the three areas analyzed. The neuronal loss was higher in the medial striatum region of the animals of groups I and I + A. The protein expression of CASPASE -3 was higher than that of XIAP in the groups I and I + A for both proteins.

CONCLUSION

The expression of XIAP was slightly higher where the histopathological changes and expression of CASPASE -3 was less evident.

Membrane depolarization and aberrant lipid distributions in the neonatal rat brain following hypoxic-ischaemic insult

Neonatal hypoxic-ischaemic (HI) encephalopathy is among the most serious complications in neonatology. In the present study, we studied the immediate (0 hour), subacute (36 hours) and late (144 hours) responses of the neonatal brain to experimental HI insult in laboratory rats. At the striatal level, the mass spectrometry imaging revealed an aberrant plasma membrane distribution of Na⁺/K⁺ ions in the oedema-affected areas. The failure of the Na⁺/K⁺ gradients was also apparent in the magnetic resonance imaging measurements, demonstrating intracellular water accumulation during the acute phase of the HI insult. During the subacute phase, compared with the control brains, an incipient accumulation of an array of N-acylphosphatidylethanolamine (NAPE) molecules was detected in the HI-affected brains, and both the cytotoxic and vasogenic types of oedema were detected. In the severely affected brain areas, abnormal distributions of the monosialogangliosides GM2 and GM3 were observed in two-thirds of the animals exposed to the insult. During the late stage, a partial restoration of the brain tissue was observed in most rats in both the in vivo and ex vivo studies. These specific molecular changes may be further utilized in neonatology practice in proposing and testing novel therapeutic strategies for the treatment of neonatal HI encephalopathy.

The Energy Costs of Prematurity and the Neonatal Intensive Care Unit (NICU) Experience

Premature neonates are in an energy deficient state due to (1) oxygen desaturation and hypoxia events, (2) painful and stressful stimuli, (3) illness, and (4) neurodevelopmental energy requirements. Failure to correct energy deficiency in premature infants may lead to adverse effects such as neurodevelopmental delay and negative long-term metabolic and cardiovascular outcomes. The effects of energy dysregulation and the challenges that clinicians in the Neonatal Intensive Care Unit (NICU) face in meeting the premature infant's metabolic demands are discussed. Specifically, the focus is on the effects of pain and stress on energy homeostasis. Energy deficiency is a complex problem and requires a multi-faceted solution to promote optimum development of premature infants.

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity. Here, a detailed protocol is described for the pretreatment and detection of catecholamines with high pressure liquid chromatography with electrochemical detection (HPLC-ECD) in real urine samples of infants, using electrospun composite nanofibers composed of polymeric crown ether with polystyrene as adsorbent, also known as the packed-fiber solid phase extraction (PFSPE) method. We show how urine samples can be easily precleaned by a nanofiber-packed solid phase column, and how the analytes in the sample can be rapidly enriched, desorbed, and detected on an ECD system. PFSPE greatly simplifies the pretreatment procedures for biological samples, allowing for decreased time, expense, and reduction of the loss of targets. Overall, this work illustrates a simple and convenient protocol for solid-phase extraction coupled to an HPLC-ECD system for simultaneous determination of three monoamine neurotransmitters (norepinephrine (NE), epinephrine (E), dopamine (DA)) and two of their metabolites (3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxy-phenylacetic acid (DOPAC)) in infants' urine. The established protocol was applied to assess the differences of urinary catecholamines and their metabolites between high-risk infants with perinatal brain damage and healthy controls. Comparative analysis revealed a significant difference in urinary MHPG between the two groups, indicating that the catecholamine metabolites may be an important candidate marker for early diagnosis of cases at risk for brain damage in infants.

Cerebral glucose deficiency versus oxygen deficiency in neonatal encephalopathy

Hypoxic-ischemic encephalopathy (HIE) in newborn infants is generally considered to result from decreased arterial oxygen content or cerebral blood flow. Cerebral injury similar to that of HIE has been noted with hypoglycemia. Studies in fetal lambs have shown that ventilation with 3% oxygen did not change cerebral blood flow, but ventilation with 100% oxygen resulted in marked reduction in cerebral blood flow, glucose delivery and glucose consumption. Blood glucose concentration falls markedly after birth; this, associated with the fall in cerebral blood flow, greatly reduces glucose supply to the brain. In preterm infants, blood glucose levels tend to be very low. Also persistent patency of the ductus arteriosus may reduce cerebral flow in diastole, thus exaggerating the decrease in glucose supply. I propose that glycopenic-ischemic encephalopathy is a more appropriate term for the cerebral insult. We should consider more aggressive management of the low blood glucose concentrations in the neonate, and particularly in preterm infants. Administration of high levels of oxygen in inspired air should be avoided to reduce the enhancement of cerebral vasoconstriction and decreased flow that normally occurs after birth.

Hypoxia in CNS Pathologies: Emerging Role of miRNA-Based Neurotherapeutics and Yoga Based Alternative Therapies

Cellular respiration is a vital process for the existence of life. Any condition that results in deprivation of oxygen (also termed as hypoxia) may eventually lead to deleterious effects on the functioning of tissues. Brain being the highest consumer of oxygen is prone to increased risk of hypoxia-induced neurological insults. This in turn has been associated with many diseases of central nervous system (CNS) such as stroke, Alzheimer's, encephalopathy etc. Although several studies have investigated the pathophysiological mechanisms underlying ischemic/hypoxic CNS diseases, the knowledge about protective therapeutic strategies to ameliorate the affected neuronal cells is meager. This has augmented the need to improve our understanding of the hypoxic and ischemic events occurring in the brain and identify novel and alternate treatment modalities for such insults. MicroRNA (miRNAs), small non-coding RNA molecules, have recently emerged as potential neuroprotective agents as well as targets, under hypoxic conditions. These 18-22 nucleotide long RNA molecules are profusely present in brain and other organs and function as gene regulators by cleaving and silencing the gene expression. In brain, these are known to be involved in neuronal differentiation and plasticity. Therefore, targeting miRNA expression represents a novel therapeutic approach to intercede against hypoxic and ischemic brain injury. In the first part of this review, we will discuss the neurophysiological changes caused as a result of hypoxia, followed by the contribution of hypoxia in the neurodegenerative diseases. Secondly, we will provide recent updates and insights into the roles of miRNA in the regulation of genes in oxygen and glucose deprived brain in association with circadian rhythms and how these can be targeted as neuroprotective agents for CNS injuries. Finally, we will emphasize on alternate breathing or yogic interventions to overcome the hypoxia associated anomalies that could ultimately lead to improvement in cerebral perfusion.

MicroRNA-210 Suppresses Junction Proteins and Disrupts Blood-Brain Barrier Integrity in Neonatal Rat Hypoxic-Ischemic Brain Injury

Cerebral edema, primarily caused by disruption of the blood-brain barrier (BBB), is one of the serious complications associated with brain injury in neonatal hypoxic-ischemic encephalopathy (HIE). Our recent study demonstrated that the hypoxic-ischemic (HI) treatment significantly increased microRNA-210 (miR-210) in the neonatal rat brain and inhibition of miR-210 provided neuroprotection in neonatal HI brain injury. The present study aims to determine the role of miR-210 in the regulation of BBB integrity in the developing brain. miR-210 mimic was administered via intracerebroventricular injection (i.c.v.) into the brain of rat pups. Forty-eight hours after the injection, a modified Rice-Vannucci model was conducted to produce HI brain injury. Post-assays included cerebral edema analysis, western blotting, and immunofluorescence staining for serum immunoglobulin G (IgG) leakage. The results showed that miR-210 mimic exacerbated cerebral edema and IgG leakage into the brain parenchyma. In contrast, inhibition of miR-210 with its complementary locked nucleic acid oligonucleotides (miR-210-LNA) significantly reduced cerebral edema and IgG leakage. These findings suggest that miR-210 negatively regulates BBB integrity i n the neonatal brain. Mechanistically, the seed sequences of miR-210 were identified complementary to the 3' untranslated region (3' UTR) of the mRNA transcripts of tight junction protein occludin and adherens junction protein β-catenin, indicating downstream targets of miR-210. This was further validated by in vivo data showing that miR-210 mimic significantly reduced the expression of these junction proteins in rat pup brains. Of importance, miR-210-LNA preserved the expression of junction proteins occludin and β-catenin from neonatal HI insult. Altogether, the present study reveals a novel mechanism of miR-210 in impairing BBB integrity that contributes to cerebral edema formation after neonatal HI insult, and provides new insights in miR-210-LNA mediated neuroprotection in neonatal HI brain injury.

Morphological and immunohistochemical analysis of apoptosis in the cerebellum of rats subjected to focal cerebral ischemia with or without alcoholism model

PURPOSE:

To evaluated histopathological changes, morphometric and expression of proteins CASPASE-3, BCL-2 and XIAP related to apoptosis in the cerebellum after induction of temporary focal cerebral ischemia followed by reperfusion, with or without a model of chronic alcoholism.

METHODS:

Fifty Wistar rats were used and divided into: control group (C), sham group (S), ischemic group (I), alcoholic group (A), and ischemic and alcoholic group (IA). The cerebellum samples collected were stained for histopathological and morphometric analysis and immunohistochemistry study.

RESULTS:

Histopathological changes were observed a greater degree in animals in groups A and IA. The morphometric study showed no difference in the amount of cells in the granular layer of the cerebellum between the groups. The expression of CASPASE-3 was higher than BCL-2 and XIAP in the groups A and IA.

CONCLUSION:

We observed correlation between histopathological changes and the occurrence of apoptosis in cerebellar cortex.

Neonatal Hypoxia Ischaemia: Mechanisms, Models, and Therapeutic Challenges

Neonatal hypoxia-ischaemia (HI) is the most common cause of death and disability in human neonates, and is often associated with persistent motor, sensory, and cognitive impairment. Improved intensive care technology has increased survival without preventing neurological disorder, increasing morbidity throughout the adult population. Early preventative or neuroprotective interventions have the potential to rescue brain development in neonates, yet only one therapeutic intervention is currently licensed for use in developed countries. Recent investigations of the transient cortical layer known as subplate, especially regarding subplate's secretory role, opens up a novel set of potential molecular modulators of neonatal HI injury. This review examines the biological mechanisms of human neonatal HI, discusses evidence for the relevance of subplate-secreted molecules to this condition, and evaluates available animal models. Neuroserpin, a neuronally released neuroprotective factor, is discussed as a case study for developing new potential pharmacological interventions for use post-ischaemic injury.

Molecular mechanisms of brain-derived neurotrophic factor in neuro-protection: Recent developments

Neuronal cell injury, as a consequence of acute or chronic neurological trauma, is a significant cause of mortality around the world. On a molecular level, the condition is characterized by widespread cell death and poor regeneration, which can result in severe morbidity in survivors. Potential therapeutics are of major interest, with a promising candidate being brain-derived neurotrophic factor (BDNF), a ubiquitous agent in the brain which has been associated with neural development and may facilitate protective and regenerative effects following injury. This review summarizes the available information on the potential benefits of BDNF and the molecular mechanisms involved in several pathological conditions, including hypoxic brain injury, stroke, Alzheimer's disease and Parkinson's disease. It further explores the methods in which BDNF can be applied in clinical and therapeutic settings, and the potential challenges to overcome.

Neonatal Hypoxic-ischemic Encephalopathy: A Radiological Review

Neonatal hypoxic-ischemic encephalopathy (HIE) is a devastating condition that may result in death or severe neurologic deficits in children. Neuroimaging with cranial ultrasound (US), computed tomography and magnetic resonance imaging are valuable tools in the workup of patients with HIE. The pattern of brain injury depends on the severity and duration of hypoxia and degree of brain maturation. Mild to moderate HI injury results in periventricular leukomalacia and germinal matrix bleed in preterm neonates, and parasagittal watershed infarcts in full-term neonates. Severe HI injury involves deep gray matter in both term and preterm infants. Treatment of HIE is largely supportive. The current article reviews the etiopathophysiology and clinical manifestations of HIE, role of imaging in the evaluation of the condition, patterns of brain injury in term and preterm neonates, the treatment and the prognosis.

Mother-infant interactions and regional brain volumes in infancy: an MRI study

It is generally agreed that the human brain is responsive to environmental influences, and that the male brain may be particularly sensitive to early adversity. However, this is largely based on retrospective studies of older children and adolescents exposed to extreme environments in childhood. Less is understood about how normative variations in parent–child interactions are associated with the development of the infant brain in typical settings. To address this, we used magnetic resonance imaging to investigate the relationship between observational measures of mother–infant interactions and regional brain volumes in a community sample of 3- to 6-month-old infants (N = 39). In addition, we examined whether this relationship differed in male and female infants. We found that lower maternal sensitivity was correlated with smaller subcortical grey matter volumes in the whole sample, and that this was similar in both sexes. However, male infants who showed greater levels of positive communication and engagement during early interactions had smaller cerebellar volumes. These preliminary findings suggest that variations in mother–infant interaction dimensions are associated with differences in infant brain development. Although the study is cross-sectional and causation cannot be inferred, the findings reveal a dynamic interaction between brain and environment that may be important when considering interventions to optimize infant outcomes.

Hypothermia-treated neonates with hypoxic-ischemic encephalopathy: Optimal timing of quantitative ADC measurement to predict disease severity

To determine the optimal time window for MR imaging with quantitative ADC measurement in neonatal HIE after hypothermia treatment, a retrospective review was performed on consecutive hypothermia-treated term neonates with HIE, with an initial and follow-up MR imaging within the first two weeks of life. Three neuroradiologists categorized each set of MR imaging as normal, mild, moderate or severe HIE based on a consensus review of the serial imaging. The lowest ADC values from the white matter, corpus callosum, and basal ganglia/thalamus were measured. The ADC values between mild-moderate and severe HIE were compared using a Student's t-test over a range of different time windows. A total of 33 MR imaging examinations were performed on 16 neonates that included three normal, four mild, five moderate, and four severe HIE. The time window of 3-10 days showed a statistically significant decrease in ADC value in severe HIE compared to mild-moderate HIE in all three locations, respectively: white matter 0.5 ± 0.22 versus 0.83 ± 0.27 ( p value 0.01), corpus callosum 0.69 ± 0.19 versus 0.91 ± 0.17 ( p value 0.01), and basal ganglia/thalamus 0.63 ± 0.16 versus 0.98 ± 0.06 ( p value <0.01). The range of 3-10 days is the optimal time window for MR imaging with quantitative ADC after hypothermia treatment.

Toward a Theory of Stuttering

Stuttering affects about 1% of the general population and from 8 to 11% of children. The onset of persistent developmental stuttering (PDS) typically occurs between 2 and 4 years of age. The etiology of stuttering is unknown and a unifying hypothesis is lacking. Clues to the pathogenesis of stuttering include the following observations: PDS is associated with adverse perinatal outcomes and birth-associated trauma; stuttering can recur or develop in adulthood following traumatic events such as brain injury and stroke; PDS is associated with structural and functional abnormalities in the brain associated with speech and language; and stuttering resolves spontaneously in a high percentage of affected children. Evidence marshaled from the literature on stuttering and from related sources suggests the hypothesis that stuttering is a neuro-motor disorder resulting from perinatal or later-onset hypoxic-ischemic injury (HII), and that chronic stuttering and its behavioral correlates are manifestations of recurrent transient ischemic episodes affecting speech-motor pathways. The hypothesis could be tested by comparing children who stutter and nonstutterers (controls) in terms of the occurrence of perinatal trauma, based on birth records, and by determining rates of stuttering in children exposed to HII during the perinatal period. Subject to testing, the hypothesis suggests that interventions to increase brain perfusion directly could be effective both in the treatment of stuttering and its prevention at the time of birth or later trauma.

Effect of Phenobarbital on Nitric Oxide Level in Term Newborn Infants with Perinatal Asphyxia

OBJECTIVES

Perinatal asphyxia (PA) is very significant in perinatal medicine due to the involvement of the central nervous system. This study was conducted to investigate the biochemical, clinical, and paraclinical changes associated with phenobarbital administration in neonates with PA.

METHODS

In this prospective, case-control study, 30 neonates with PA in two groups of 15 each (case and control) were investigated. The case group received 20 mg/kg intravenous phenobarbital within six hours of birth, and the control group did not receive phenobarbital. Serum concentrations of nitric oxide (NO) were measured at enrollment and one week after birth in the two groups. Clinical, electroencephalography, and magnetic resonance imaging findings of the two groups were compared.

RESULTS

At enrollment, the two groups did not differ in clinical severity, seizure incidence, or NO concentration. After one week, NO concentration was significantly lower in the case group (p < 0.050), but there was no significant difference in other variables between the two groups.

CONCLUSIONS

Early administration of phenobarbital in term neonates with PA could protect them against encephalopathy.