Brain development in newborns and infants after ECMO.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) not only significantly improves survival rates in severely ill neonates but also is associated with long-term neurodevelopmental issues. To systematically review the available literature on the neurodevelopmental outcomes of neonates and infants who have undergone ECMO treatment, with a focus on motor deficits, cognitive impairments, sensory impairments, and developmental delays. This review aims to understand the incidence, prevalence, and risk factors for these problems and to explore current nursing care and management strategies. DATA SOURCES: A comprehensive literature search was performed across PubMed, EMBASE, and Web of Science using a wide array of keywords and phrases pertaining to ECMO, neonates, infants, and various facets of neurodevelopment. The initial screening involved reviewing titles and abstracts to exclude irrelevant articles, followed by a full-text assessment of potentially relevant literature. The quality of each study was evaluated based on its research methodology and statistical analysis. Moreover, citation searches were conducted to identify potentially overlooked studies. Although the focus was primarily on neonatal ECMO, studies involving children and adults were also included due to the limited availability of neonate-specific literature. RESULTS: About 50% of neonates post-ECMO treatment exhibit varying degrees of brain injury, particularly in the frontal and temporoparietal white matter regions, often accompanied by neurological complications. Seizures occur in 18%-23% of neonates within the first 24 hours, and bleeding events occur in 27%-60% of ECMO procedures, with up to 33% potentially experiencing ischemic strokes. Although some studies suggest that ECMO may negatively impact hearing and visual development, other studies have found no significant differences; hence, the influence of ECMO remains unclear. In terms of cognitive, language, and intellectual development, ECMO treatment may be associated with potential developmental delays, including lower composite scores in cognitive and motor functions, as well as potential language and learning difficulties. These studies emphasize the importance of early detection and intervention of potential developmental issues in ECMO survivors, possibly necessitating the implementation of a multidisciplinary follow-up plan that includes regular neuromotor and psychological evaluations. Overall, further multicenter, large-sample, long-term follow-up studies are needed to determine the impact of ECMO on these developmental aspects. CONCLUSIONS: The impact of ECMO on an infant's nervous system still requires further investigation with larger sample sizes for validation. Fine-tuned management, comprehensive nursing care, appropriate patient selection, proactive monitoring, nutritional support, and early rehabilitation may potentially contribute to improving the long-term outcomes for these infants.

Targeting the Main Sources of Reactive Oxygen Species Production: Possible Therapeutic Implications in Chronic Pain.

Humans have long been combating chronic pain. In clinical practice, opioids are first- choice analgesics, but long-term use of these drugs can lead to serious adverse reactions. Finding new, safe and effective pain relievers that are useful treatments for chronic pain is an urgent medical need. Based on accumulating evidence from numerous studies, excess reactive oxygen species (ROS) contribute to the development and maintenance of chronic pain. Some antioxidants are potentially beneficial analgesics in the clinic, but ROS-dependent pathways are completely inhibited only by scavenging ROS directly targeting cellular or subcellular sites. Unfortunately, current antioxidant treatments donot achieve this effect. Furthermore, some antioxidants interfere with physiological redox signaling pathways and fail to reverse oxidative damage. Therefore, the key upstream processes and mechanisms of ROS production that lead to chronic pain in vivo must be identified to discover potential therapeutic targets related to the pathways that control ROS production in vivo. In this review, we summarize the sites and pathways involved in analgesia based on the three main mechanisms by which ROS are generated in vivo, discuss the preclinical evidence for the therapeutic potential of targeting these pathways in chronic pain, note the shortcomings of current research and highlight possible future research directions to provide new targets and evidence for the development of clinical analgesics.

Dysfunction of the Brain-derived Neurotrophic Factor-Tyrosine Kinase B Signaling Pathway Contributes to Learning and Memory Impairments Induced by Neuroinflammation in Mice.

Accumulating evidence suggests that neuroinflammation is the main mechanism in cognitive dysfunction and that brain-derived neurotrophic factor (BDNF) is involved in learning and memory by binding to tyrosine kinase B (TrkB) receptors. Herein, we tested the roles of the BDNF-TrkB signaling pathway and its downstream cascade in lipopolysaccharide (LPS) induced cognitive dysfunction in mice. Mice were treated with LPS (0.25 mg/kg) for 7 days, and learning and memory function was evaluated by the novel object recognition test (NORT). Western blotting was performed to elucidate roles of the BDNF-TrkB signaling pathway and its downstream cascades in LPS mice. The NORT showed that LPS induced learning and memory deficits in mice. The levels of IL-1ß, IL-6, and TNF-α in the serum and central nervous system decreased in LPS mice. In addition, LPS reduced the protein levels of BDNF, p-TrkB, Bcl-2, p-ERK1/2, p-CaMK2, p-CREB and p-GluR1 and increased the expression of Bax in the hippocampus and medial prefrontal cortex regions. In the entorhinal cortex, the protein levels of BDNF, p-TrkB, Bcl-2, p-CaMK2 and p-CREB were decreased, and the protein level of Bax was increased in LPS mice. Interestingly, 7,8-DHF alleviated these disorders in LPS mice and improved learning and memory function; however, the TrkB antagonist ANA12 effectively reversed effects of 7,8-DHF. Therefore, we conclude that the BDNF-TrkB signaling pathway and its downstream cascades disorders in different regions are main mechanisms of cognitive dysfunction, and 7,8-DHF maybe useful as a new treatment for preventing or treating cognitive dysfunction induced by neuroinflammation in neurodegenerative diseases.

Naringenin promoted spinal microglia M2 polarization in rat model of cancer-induced bone pain via regulating AMPK/PGC-1α signaling axis.

Cancer-induced bone pain (CIBP) treatment remains a clinical challenge because the pathophysiological mechanisms are not fully understood. Recently, it was verified that shifting microglial polarization toward the M2 phenotype reveals a potential strategy for CIBP treatment. Naringenin, a natural flavone flavonoid, has been reported to have antioxidant, anti-inflammatory and neuroprotective properties. However, the role of naringenin on regulating microglial polarization in CIBP rats and the molecular mechanisms participating in this process have not been fully clarified. Herein, we investigated the potential effect of naringenin on M1/M2 microglial polarization and further explored the potential mechanisms of this action. Our study demonstrated that intraperitoneal administration of naringenin could upregulate the antioxidative molecule glutathione peroxidase 4 (GPx4) level in the spinal cord, as well as bone cancer-induced mechanical allodynia in rats. Moreover, naringenin treatment also suppressed microglia-mediated neuroinflammation by downregulating the phosphorylation of nuclear factor κB (NF-κB) p65 expression and promoting microglial polarization toward the M2 phenotype in CIBP rats. The promoting effects mediated by naringenin on M1/M2 microglial polarization are dependent on the serine/threonine protein kinase adenosine monophosphate-activated protein kinase (AMPK)/proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling pathway. Inhibition of AMPK activation with the classical AMPK inhibitor Compound C attenuated this effect of naringenin. These results improved the understanding of the anti-inflammatory property of naringenin on microglial polarization, which might provide new alternative avenues for CIBP treatment.

Galectin-3 in Microglia-Mediated Neuroinflammation: Implications for Central Nervous System Diseases.

Microglial activation is one of the common hallmarks shared by various central nervous system (CNS) diseases. Based on surrounding circumstances, activated microglia play either detrimental or neuroprotective effects. Galectin-3 (Gal-3), a group of ß-galactoside-binding proteins, has been cumulatively revealed to be a crucial biomarker for microglial activation after injuries or diseases. In consideration of the important role of Gal-3 in the regulation of microglial activation, it might be a potential target for the treatment of CNS diseases. Recently, Gal-3 expression has been extensively investigated in numerous pathological processes as a mediator of neuroinflammation, as well as in cell proliferation. However, the underlying mechanisms of Gal-3 involved in microgliamediated neuroinflammation in various CNS diseases remain to be further investigated. Moreover, several clinical studies support that the levels of Gal-3 are increased in the serum or cerebrospinal fluid of patients with CNS diseases. Thus, we summarized the roles and underlying mechanisms of Gal-3 in activated microglia, thus providing a better insight into its complexity expression pattern, and contrasting functions in CNS diseases.

ß2-adrenoreceptor agonist ameliorates mechanical allodynia in paclitaxel-induced neuropathic pain via induction of mitochondrial biogenesis.

Chemotherapy-induced neuropathic pain is a debilitating and common side effect of cancer treatment and so far no effective drug is available for treatment of the serious side effect. Previous studies have demonstrated ß2-adrenoreceptor (ADRB2) agonists can attenuate neuropathic pain. However, the role of ADRB2 in paclitaxel -induced neuropathic pain (PINP) remains unclear. In this study, we investigated the effect of formoterol, a long-acting ADRB2 agonist, and related mechanisms in PINP. A rat model of PINP was established by intraperitoneal injection of paclitaxel (2 mg/kg) every other day with a final cumulative dose of 8 mg/kg. Hind paw withdrawal thresholds (PWTs) in response to von Frey filament stimuli were used to evaluate mechanical allodynia. Western blot was used to examine the expression of ADRB2, peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), nuclear respiratory factors 1 (NRF1) and mitochondrial transcription factor A (TFAM) and the immunofluorescence was to detect the cellular localization of ADRB2 and PGC-1α in the spinal cord. Moreover, we measured mitochondrial DNA (mtDNA) copy number by qPCR. In our study, formoterol attenuated established PINP and delayed the onset of PINP. Formoterol restored ADRB2 expression as well as mtDNA copy number and PGC-1α, NRF1, and TFAM protein expression, which are major genes involved in mitochondrial biogenesis, in the spinal cord of PINP rats. Moreover, we found the analgesic effect of formoterol against PINP was partially abolished by PGC-1α inhibitor SR-18292. Collectively, these results demonstrated the activation of ADRB2 with formoterol ameliorates PINP at least partially through induction of mitochondrial biogenesis.

Src-family protein tyrosine kinases: A promising target for treating chronic pain.

Despite the growing knowledge of the mechanisms of chronic pain, the treatment of this disorder in the clinic remains a major challenge. Src-family protein tyrosine kinases (SFKs), a group of non-receptor protein tyrosine kinases, have been implicated in neuronal development and synaptic plasticity. SFKs are critical for the regulate of N-methyl-D-aspartic acid receptor (NMDAR) 2B subunit phosphorylation by various transmembrane receptors, e.g., G-protein coupled receptors (GPCRs), EphB receptors (EphBRs), increased intracellular calcium, epidermal growth factor (EGF) and other growth factors, and thus contribute to the development of chronic pain. SFKs have also been regarded as important points of convergence of intracellular signalling components for the regulation of microglial functions and the immune response. Additionally, the intrathecal administration of SFK inhibitors significantly alleviates mechanical allodynia in different chronic pain models. Here, we reviewed the current evidence for the role of SFKs in the development of chronic pain caused by complete Freund's adjuvant (CFA) injection, peripheral nerve injury (PNI), streptozotocin (STZ) injection and bone metastasis. Moreover, the role of SFKs in the development of morphine tolerance is also discussed. The regulation of SFKs therefore has emerged as a potential therapeutic target for the treatment of chronic pain in terms of safety and efficacy.

Relationship between phenotype and genotype of 102 Chinese newborns with Prader-Willi syndrome.

High rates of misdiagnosis and delayed intervention in neonatal PWS are leading to poor prognoses. To determine the clinical and image characteristics of newborns with Prader-Willi syndrome (PWS). A total of 102 cases of newborns definitively diagnosed with PWS at the Children's Hospital of Fudan University from 02/2014 to 12/2017 were retrospectively analyzed. We analyzed the modulated voxel-based morphology (VBM) of gray matter in PWS by T2 weighted imaging. Of 102 cases, 75 (73.5%) have paternal deletion of 15q11.2-q13, whereas 27 (26.5%) have maternal uniparental disomy (UPD). Of the 75 deletion cases, 75 (100%) week crying, 71 (94.7%) hypotonia, 70 (93.3%) poor feeding, 46 (61.3%) hypopigmentation, 43 (57.3%) male cryptorchidism, 10 (13.3%) female labia minora, 48 (64%) characteristic facial features. Of 27 UPD cases, 27 (100%) week crying and hypotonia, 25 (92.6%) hypophagia, 20 (74.1%) male cryptorchidism, 1 (3.7%) female labia minora, 19 (70.4%) characteristic facial features, 12 (44.4%) hypopigmentation. The modulated VBM analysis shows that the middle frontal gyrus, orbitofrontal cortex (middle), and inferior frontal gyrus are the most variable brain regions that determine the endo-phenotype difference between the two genotypes. Hypotonia, hypophagia, and maldevelopment of sexual organs are general characteristics of newborns with PWS in Chinese population. In UPD cases, the proportions of premature newborns, elderly parturient women and congenital malformations were higher than for paternal deletion cases. The differences in the gray matter volume of these three regions between the two genotypes may explain the differences in maladaptive behaviors and emotions.

The therapeutic potential of GABA in neuron-glia interactions of cancer-induced bone pain.

The development of effective therapeutics for cancer-induced bone pain (CIBP) remains a tremendous challenge owing to its unclear mechanisms. Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). Emerging studies have shown that disinhibition in the spinal cord dorsal horn may account for the development of chronic pain. However, the role of GABA in the development of CIBP remains elusive. In addition, accumulating evidence has shown that neuroglial cells in the peripheral nervous system, especially astrocytes and microglial cells, played an important role in the maintenance of CIBP. In this study, we investigated the expression of GABA and Gamma-aminobutyric acid transporter-1 (GAT-1), a transporter of GABA. Our results demonstrate that GABA was decreased in CIBP rats as expected. However, the expression of glutamic acid decarboxylase (GAD) 65 was up-regulated on day 21 after surgery, while the expression of GAD 67 remained unchanged after surgery. We also found that the expression of GAT-1 was up-regulated mainly in the astrocytes of the spinal cord. Moreover, we evaluated the analgesic effect of exogenous GABA and the GAT-1 inhibitor. Intrathecal administration of exogenous GABA and NO-711 (a GAT-1 selective inhibitor) significantly reversed CIBP-induced mechanical allodynia in a dose-dependent manner. These results firstly show that neuron-glia interactions, especially on the GABAergic pathway, contribute to the development of CIBP. In conclusion, exogenous GABA and GAT-1 inhibitor might be alternative therapeutic strategies for the treatment of CIBP.

Human rhinovirus internal ribosome entry site element enhances transgene expression in transfected CHO-S cells.

Chinese hamster ovary (CHO) cells are mainly used for recombinant protein production. However, the unstable transgene expression and lower transgene copy numbers are the major issues need to be resolved. Here, eleven internal ribosome entry site (IRES) elements from viral and cellular IRES were evaluated for foreign gene expression in CHO-S cells. We constructed eleven fusing plasmids containing different IRES sequences downstream of the enhanced green fluorescent protein (EGFP) gene. EGFP expression was detected by flow cytometry and the transgene copy number was evaluated by quantitative PCR. The erythropoietin (EPO) protein was also used to assess the stronger IRES. The results showed that IRES from human rhinovirus (HRV) exhibited the highest EGFP expression level under transient and stable transfections. The EGFP expression level of vector with IRES from HRV was related to the gene copy number in stably transfected CHO-S cells. Moreover, IRES from HRV induced higher expression level of EPO compared with one mutant IRES from EMCV in transfected cells. In conclusion, IRES from HRV can function as a strong IRES element for stable expression in CHO-S cells, which could potentially guide more effective foreign gene expression in CHO-S cells.

Novel compound heterozygous mutations in the PEX1 gene in two Chinese newborns with Zellweger syndrome based on whole exome sequencing.

Peroxisome biogenesis disorders (PBDs) represent a spectrum of human genetic disorders that are characterized by damaged peroxisome assembly. In the newborn period, the characteristics of affected patients include dysmorphic facial features, neonatal hypotonia, seizures, ocular abnormalities, poor feeding, liver cysts with hepatic dysfunction and skeletal defects. These can be caused by a defect in at least 14 different PEX genes. In this study, whole-exome sequencing (WES) was performed on samples from two Chinese newborns with clinical features of Zellweger syndrome. WES identified two novel mutations (c.2416+1G>T and c.2489delT) in patient 1 and another two novel mutations (c.1483+1G>A and c.1727dupG) in patient 2 in the PEX1 gene. All four mutations have a serious influence on the protein function, which also highlights the power of WES, particularly in clinically challenging cases.

Effects of lead exposure on dendrite and spine development in hippocampal dentate gyrus areas of rats.

Lead exposure has been implicated in the impairment of synaptic plasticity in the hippocampal dentate gyrus (DG) areas of rats. However, whether the degradation of physiological properties is based on the morphological alteration of granule neurons in DG areas remains elusive. Here, we examined the dendritic branch extension and spine formation of granule neurons after lead exposure during development in rats. Dendritic morphology was studied using Golgi-Cox stain method, which was followed by Sholl analysis at postnatal days 14 and 21. Our results indicated that, for both ages, lead exposure significantly decreased the total dendritic length and spine density of granule neurons in the DG of the rat hippocampus. Further branch order analysis revealed that the decrease of dendritic length was observed only at the second branch order. Moreover, there were obvious deficits in the proportion and size of mushroom-type spines. These deficits in spine formation and maturity were accompanied by a decrease in Arc/Arg3.1 expression. Our present findings are the first to show that developmental lead exposure disturbs branch and spine formation in hippocampal DG areas. Arc/Arg3.1 may have a critical role in the disruption of neuronal morphology and synaptic plasticity in lead-exposed rats.

Chronic Lead Exposure and Mixed Factors of Gender×Age×Brain Regions Interactions on Dendrite Growth, Spine Maturity and NDR Kinase.

NDR1/2 kinase is essential in dendrite morphology and spine formation, which is regulated by cellular Ca2+. Lead (Pb) is a potent blocker of L-type calcium channel and our recent work showed Pb exposure impairs dendritic spine outgrowth in hippocampal neurons in rats. But the sensitivity of Pb-induced spine maturity with mixed factors (gender×age×brain regions) remains unknown. This study aimed to systematically investigate the effect of Pb exposure on spine maturity in rat brain with three factors (gender×age×brain regions), as well as the NDR1/2 kinase expression. Sprague-Dawley rats were exposed to Pb from parturition to postnatal day 30, 60, 90, respectively. Golgi-Cox staining was used to examine spine maturity. Western blot assay was applied to measure protein expression and real-time fluorescence quantitative PCR assay was used to examine mRNA levels. The results showed chronic Pb exposure significantly decreased dendritic length and impaired spine maturity in both rat hippocampus and medial prefrontal cortex. The impairment of dendritic length induced by Pb exposure tended to adolescence > adulthood, hippocampus > medial prefrontal cortex and female > male. Pb exposure induced significant damage in spine maturity during adolescence and early adult while little damage during adult in male rat brain and female medial prefrontal cortex. Besides, there was sustained impairment from adolescence to adulthood in female hippocampus. Interestingly, impairment of spine maturity followed by Pb exposure was correlated with NDR1/2 kinase. The reduction of NDR1/2 kinase protein expression after Pb exposure was similar to the result of spine maturity. In addition, NDR2 and their substrate Rabin3 mRNA levels were significantly decreased by Pb exposure in developmental rat brain. Taken together, Pb exposure impaired dendrite growth and maturity which was subject to gender×age×brain regions effects and related to NDR1/2 signal expression.

Developmental lead exposure alters synaptogenesis through inhibiting canonical Wnt pathway in vivo and in vitro.

Lead (Pb) exposure has been implicated in the impairment of synaptic plasticity in the developing hippocampus, but the mechanism remains unclear. Here, we investigated whether developmental lead exposure affects the dendritic spine formation through Wnt signaling pathway in vivo and in vitro. Sprague-Dawley rats were exposed to lead throughout the lactation period and Golgi-Cox staining method was used to examine the spine density of pyramidal neurons in the hippocampal CA1 area of rats. We found that lead exposure significantly decreased the spine density in both 14 and 21 days-old pups, accompanied by a significant age-dependent decline of the Wnt7a expression and stability of its downstream protein (ß-catenin). Furthermore, in cultured hippocampal neurons, lead (0.1 and 1 µM lead acetate) significantly decreased the spine density in a dose-dependent manner. Exogenous Wnt7a application attenuated the decrease of spine density and increased the stability of the downstream molecules in Wnt signaling pathway. Together, our results suggest that lead has a negative impact on spine outgrowth in the developing hippocampus through altering the canonical Wnt pathway.

Epigenetic histone modification regulates developmental lead exposure induced hyperactivity in rats.

Lead (Pb) exposure was commonly considered as a high environmental risk factor for the development of attention-deficit/hyperactivity disorder (ADHD). However, the molecular basis of this pathological process still remains elusive. In light of the role of epigenetics in modulating the neurological disease and the causative environment, the alterations of histone modifications in the hippocampus of rats exposed by various doses of lead, along with concomitant behavioral deficits, were investigated in this study. According to the free and forced open field test, there showed that in a dosage-dependent manner, lead exposure could result in the increased locomotor activity of rats, that is, hyperactivity: a subtype of ADHD. Western blotting assays revealed that the levels of histone acetylation increased significantly in the hippocampus by chronic lead exposure, while no dramatic changes were detected in terms of expression yields of ADHD-related dopaminergic proteins, indicating that histone acetylation plays essential roles in this toxicant-involved pathogenesis. In addition, the increased level of histone acetylation might be attributed to the enzymatic activity of p300, a typical histone acetyltransferase, as the transcriptional level of p300 was significantly increased upon higher-dose Pb exposure. In summary, this study first discovered the epigenetic mechanism bridging the environmental influence (Pb) and the disease itself (ADHD) in the histone modification level, paving the way for the comprehensive understanding of ADHD's etiology and in further steps, establishing the therapy strategy of this widespread neurological disorder.

Facile domino access to chiral mono-, bi-, and tricyclic 2,3-dihydrofurans.

The asymmetric domino Michael-S(N)2 reaction of various 1,3-dicarbonyl compounds to α-bromonitroalkenes is described for the first time, employing readily available cinchona-derived bifunctional thioureas as organocatalysts. The novel transformations were highly regio-, chemo-, diastereo-, and enantioselective, which simultaneously gave the chiral tricyclic 2,3-dihydrofurans, bicyclic 2,3-dihydrofurans, and tetrasubstituted 2,3-dihydrofurans with two vicinal chiral carbon centers.