CNS & Neurological Disorders - Drug Targets (Formerly Current Drug Targets - CNS & Neurological Disorders) - Volume 14, Issue 1, 2015

Perinatal asphyxia (PA) still constitutes a common complication involving a large number of infants with or without congenital heart diseases (CHD). PA affects 0.2-0.6% of full-term neonates, 20% of which suffer mortal hypoxic-ischemic encephalopathy, and among survivors 25% exhibit permanent consequences at neuropsychological level. Each year, about one third of 1000 live births underwent to surgical intervention in early infancy and/or are at risk for ominous outcome. Advances in brain monitoring, in anesthetic and cardiothoracic surgical techniques, including selective or total body cooling, cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest, have essentially reduced mortality expanding the possibility to address functional neurologic and cardiac outcomes in long-term survivors. However, open-heart surgery constitutes a time-frame of planned ischemia-reperfusion injury, which is a price to pay in the treatment or palliation of CHD. Infants who underwent heart surgery and non-CHD infants complicated by PA share similarities in their neurodevelopmental profile and a common form of brain damage due to hypoxic–ischemic injury. The purpose of the present review was to evaluate different mechanisms implicated in brain injury following CPB and PA and how it is possible to monitor such injury by means of available biomarkers (S100B protein, Activin A, Adrenomedullin).

Herein, we assessed the expression of transglutaminase-2 (TG2) during in vitro neural differentiation of human Mesenchymal Stem Cells (hMSCs) induced by some Growth Factors (GFs). The amount and distribution of mRNAs for some transglutaminase (TGs) isoforms (TG1, TG2, TG3, TG5) were also evaluated. In addition, we tested some neural lineage markers (Glial Acid Fibrillary Protein, GFAP; Neurofilament Protein, NF; Nestin; β-Tubulin III). A progressive increase of all neural markers during GFs neural differentiation of hMSCs was found. A significant overexpression of TG1 and TG2 mRNA was observed in undifferentiated hMSCs. GFs-treatment induced a progressive decrease of TG1 mRNA during hMSCs differentiation. A significant down-regulation of TG2 mRNA in 2 days in vitro (DIV) GFs-treated cells was observed. TG2 mRNA progressively increased during GFs hMSCs differentiation, reaching after 6 DIV of GFs-treatment of similar values to those observed in undifferentiated cells. TG3 mRNA levels were express at very low only in undifferentiated hMSCs, whereas TG5 mRNA was undetectable in undifferentiated and differentiated hMSCs. Immunocytochemical and Western blot analysis showed an overexpression of TG2 in undifferentiated hMSCs. A dramatic reduction of the protein levels in 2 DIV GFs-treated cells was observed. Its expression levels progressively increased during the differentiation of hMSCs with GFs, reaching after 6 DIV of the treatment similar values to those observed in undifferentiated cells. Our findings demonstrate the presence of multiple TGs in hMSCs during neural differentiation in vitro induced by GFs, and suggest that TG2 may be part of the downstream events associated to neural differentiation.

Hypoxic-ischemic preconditioning is an endogenous mechanism in which exposure to a sublethal episode of hypoxia-ischemia protects against a subsequent more severe episode. Although several postnatal models of hypoxic-ischemic preconditioning have been established, hardly any perinatal models exist. Therefore, the objective of this study is to validate a new rodent model. We investigate whether mild fetal asphyxia (FA) as a preconditioning stimulus, protects against severe perinatal asphyxia (PA) when looking at neonatal brain histology. FA was induced at embryonic day 17 (E17) by temporarily clamping the uterine circulation. A caesarean section was performed at E21/22 and PA was induced by submersing the uterine horns, still containing the fetuses, in a water bath. Brains were examined for histological changes at either postnatal day 7 or 14. We used terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining to detect apoptotic cell death and a glial fibrillary acidic protein (GFAP) staining to detect reactive astrocytes. Interestingly, the preconditioned group showed significantly less perinatal mortality than non-preconditioned groups. Furthermore, preconditioned animals had significantly less TUNEL-positive cells and less GFAP-positive cells in striatum, prefrontal cortex and hippocampus compared to the non-preconditioned animals that underwent PA. Consequently, mild FA might cause neuroprotection by inducing anti-apoptotic mechanisms and attenuating astrogliosis. Considering the morphological findings in the neonatal brain from this study, together with previously reported long-term behavioral outcomes in this model, we can conclude that this is a suitable experimental model to investigate mechanisms of endogenous neuroprotection in the fetal brain. Identifying these endogenous neuroprotective mechanisms will provide novel potential targets for future pharmacological intervention in asphyctic newborns.

The induction of heme oxygenase (HO), the rate-limiting enzyme in heme degradation, occurs as an adaptative response to oxidative stress and is consequent to decrease in cellular glutathione levels. Our previous studies demonstrated significant increase in survival rates of rats treated with glutathione depletors and submitted to transient cerebral ischemia. The aim of the present research was to test the effects of L-Buthionine sulfoximine (BSO), a glutathione depletor, during cerebral post-ischemic reperfusion. Cerebral ischemia was induced by bilateral clamping of common carotid arteries for 20 min. Each sample was used for glutathione ad lipid peroxidation level dosage and for evaluating the expression of heme oxygenase both after a single subcutaneous administration of BSO and without treatment. In the same experimental conditions, endothelial, inducible and neuronal Nitric Oxide Synthase (eNOS, iNOS and nNOS) and Dimethylarginine Dimethyl amine Hydrolases (DDAH-1 and DDAH-2) were also evaluated. Results obtained in the present study suggested that HO-1 over-expression may be implicated in the protective effect of BSO in post-ischemic reperfusion brain damage, although the involvement of other important stress mediators cannot be ruled out.

Introduction: Antidepressant treatment during pregnancy is speedily increasing in developed countries and this phenomenon has occurred without firm evidence on safety and/or efficacy. Aims: The present study investigated from mid-trimester of pregnancy up to 24 hours after birth the pattern of a brain damage marker, namely S100B, in maternal fetal and neonatal biological fluids of pregnant women and their newborns antenatally treated by antidepressant drugs such as selective serotonin re-uptake inhibitors (SSRI). Methods: we conducted an observational study on 75 pregnant women treated in the mid –third trimester by antidepressant drugs and 231 healthy pregnancies. S100B concentrations were measured at 7 predetermined monitoring time-points before, during and after treatment in maternal, fetal and neonatal biological fluids and correlated with neurological follow-up at 7 days from birth. Results: In SSRI group S100B concentrations were significantly higher in SSRI than controls (P<0.001, for all) in maternal blood, in amniotic fluid, in arterial and venous cord blood and at 24-h from birth. Highest (P<0.05) S100B levels were found in SSRI infants showing major neurological symptoms at 7-d follow-up. Conclusion: The present data on increased S100B levels in maternal, fetal and neonatal biological fluids suggest that SSRI administration although beneficial to the mother, presents some risks for the infant.

Transactive response DNA-binding protein of 43 kDa (TDP-43) is a nuclear DNA/RNA-binding protein involved in gene transcription and mRNA processing. Recently, TDP-43 has been found in the cytoplasmic inclusions observed in amyotrophic lateral sclerosis. Substantial attention has been devoted to the toxic effects of the cytoplasmic TDP-43 aggregates, whereas the functional role of this protein remains poorly investigated. Interestingly, TDP-43 could be localized in the synapse and affect synaptic plasticity and locomotion in Drosophila. Here, we would like to understand if TDP-43 could modulate spinal cord plasticity in a mouse model of neurotoxic motoneuron depletion. Therefore, the expression levels of TDP- 43 and synaptic proteins such as synapsin-I and the α-amino-3-hydroxy-5-methyl-4- isoxazolepropionate (AMPA) receptor subunits GluR1, GluR2 and GluR4 were measured by western blotting. By using multivariate regression models, protein expression levels were correlated each other as well as with the motor performance. The results suggested that motor performance could be linked to the expression of synapsin-I, and that the latter could depend on TDP-43, which in turn could interact with AMPA receptors. In conclusion, our results suggest that TDP-43 is likely involved in the modulation of synaptic plasticity. Given the increasing interest in mouse models of TDP-43 gain or loss of function in neurodegenerative diseases, the elucidation of the role of TDP-43 in the spinal cord is mandatory. More generally, given the recently increased knowledge about spinal cord plasticity, we postulate that the stimulation of the intrinsic plastic potential of spinal cord would be a successful repairing strategy.

Hypoxic-ischemic preconditioning (HIPC) has a neuroprotective effect against a subsequent, more severe perinatal hypoxic-ischemic episode. The protective processes of preconditioning (PC) in the immature brain remain undefined but are most likely related to the immune cells of the central nervous system. To determine the role of astrocytes in HIPC, we initially exposed primary rat astrocytes to oxygen-glucose deprivation (OGD) for 30 minutes as a PC stimulus. A subsequent more severe insult was induced 24 hours later by exposing the astrocytes to OGD for 3 hours. These experiments revealed that OGD for 3 hours induced increased cytotoxicity as measured by lactate dehydrogenase in primary astrocytes, which was diminished in astrocytes earlier subjected to PC. Moreover, decreased cell proliferation, as measured by Ki67, and lower cytokine expression (IL-1β, TNF-α, IL-6, IL-10) were observed in astrocytes subjected to OGD for 3 hours, while these levels remained unchanged in PC+OGD cells. Therefore, we speculate that PC by OGD may affect the survival, proliferation and function of primary cultured astrocytes which may partly explain the neuroprotective properties of HIPC seen in HI rat models.

A peculiar population of glial cells, Olfactory Ensheathing Cells (OECs), are able to support the continuous neuronal turn-over and sheathe olfactory axons. In vitro, they stimulate axonal growth, as produce several neurotrophic factors (GFs); in vivo they promote remyelination of damaged axons. In this in vitro study, OEC effects on survival of cortical neurons exposed to hypoxia were examined. Rat co-cultures of OECs and cortical neurons were placed both in normal and hypoxic conditions; subsequently cells were analyzed by immunocytochemistry. Furthermore, some neuronal cultures were grown with Glial cell Derived Neurotrophic Factor (GDNF) or basic Fibroblast Growth Factor (bFGF) to tentatively rescue cells from oxygen deprivation. Some cortical neurons grown in both conditions were considered as control cells. Some neuronal cultures were feed with conditioned medium from OECs. We show that both in co-cultures and with GFs-treatment there was an increase of the number of neurons in comparison with control cultures. Moreover, these neurons formed a rich axonal outgrowth. OEC-conditioned media did not affect the cell survival. In hypoxic cultures the neuron number was very low both in controls and in GFs-treated neurons, while in co-cultures and in OEC-conditioned media cultures an increased neuronal survival was observed. These data suggest that OECs promote the survival of neurons in vitro exposed to hypoxia exerting a protective influence. Since some experiments in vivo have shown that injury is often characterized by secondary insults, ischemia or hypoxia, our results suggest that OECs might be considered a possible approach for restoration in injuries.

Objective: To better understand the inflammatory response in the central nervous system (CNS) after lipopolysaccharide (LPS)-induced chorioamnionitis. Study Design: Fetal sheep were exposed to intra-amniotic LPS 2 or 14 days before preterm delivery at 125 days of gestation. mRNA levels of cytokines, TLRs and anti-oxidants were determined in different CNS regions. Results: Interleukin 1β levels increased in hippocampus, cortex and cerebellum 2 days after LPS exposure, while Interleukin 8 levels increased in the periventricular white matter as well. Levels returned back to control levels after 14 days. Tumor necrosis factor-α levels increased in hippocampus and cortex after 2 days. Toll like receptor 4 levels was upregulated in all grey matter regions 2 and 14 days after exposure. Glutathione s-transferase mRNA levels were lower after 2 and 14 days in all grey matter regions. Conclusion: Intra-amniotic LPS exposure causes acute and region-specific changes in inflammatory markers in the fetal brain, with grey matter being more affected than white matter. Condensation: Intra-amniotic LPS exposure causes acute and region-specific changes in cytokines, TLR and anti-oxidants levels, with grey matter being more affected than white matter.

S100B protein has been recently proposed as a consolidated marker of brain damage and death in adult, children and newborn patients. The present study evaluates whether the longitudinal measurement of S100B at different perioperative time-points may be a useful tool to identify the occurrence of perioperative early death in congenital heart disease (CHD) newborns. We conducted a case-control study in 88 CHD infants, without pre-existing neurological disorders or other co-morbidities, of whom 22 were complicated by perioperative death in the first week from surgery. Control group was composed by 66 uncomplicated CHD infants matched for age at surgical procedure. Blood samples were drawn at five predetermined timepoints before during and after surgery. In all CHD children, S100B levels showed a pattern characterized by a significant increase in protein’s concentration from hospital admission up to 24-h after procedure reaching their maximum peak (P<0.01) during cardiopulmonary by-pass and at the end of the surgical procedure. Moreover, S100B concentrations in CHD death group were significantly higher (P<0.01) than controls at all monitoring time-points. The ROC curve analysis showed that S100B measured before surgical procedure was the best predictor of perioperative death, among a series of clinical and laboratory parameters, reaching at a cut-off of 0.1 µg/L a sensitivity of 100% and a specificity of 63.7%. The present data suggest that in CHD infants biochemical monitoring in the perioperative period is becoming possible and S100B can be included among a series of parameters for adverse outcome prediction.

Therapeutic hypothermia has become a standard neuroprotective treatment in term newborn infants following perinatal asphyxia. Hypothermia-induced changes in the reactivity of the vessels supplying the brain might play a role in its therapeutic or side effects. We investigated the putative age-related changes and the effect of clinically relevant cooling (33°C) on the reactivity of the newborn rat carotid artery. Carotid artery rings from 2-3 days old and 9-10 days old rats were mounted in myographs and studied at 33°C and 37°C. Hypothermia did not significantly affect the contractions induced by KCl and U46619, nor the relaxations induced by acetylcholine (ACh), the nitric oxide (NO) donor sodium nitroprusside (SNP), the NO-independent stimulator of soluble guanylate cyclase (sGC) BAY 41-2272, the β -adrenoceptor agonist isoproterenol, the adenylate cyclase activator forskolin, and acute hypoxia (PO2 3 kPa). The relaxations induced by ACh, isoproterenol, the β 2-adrenoceptor agonist salbutamol, the β 3-adrenoceptor agonist CL-316243 and acute hypoxia increased with postnatal age and were impaired by endothelium removal or by inhibition of NO synthase (L-NAME) or sGC (ODQ). In contrast, the relaxations induced by SNP, BAY 41-2272 and forskolin were endothelium-independent and did not change with age. In conclusion, mild hypothermia (33°C) does not affect the reactivity of neonatal rat carotid arteries. Our data suggest a reduced NO bioavailability in the carotid artery during the first days of life. This transient reduction in endothelium-dependent relaxation might play a role in the adaptation of the circulatory system to birth and in the neonatal vascular response to insults such as hypoxia.

Objective: To compare the quality of life (QoL) of 8-18 year old children with cerebral palsy (CP) in the Southern part of The Netherlands to a sample of European children from the general population and to investigate factors associated with possible differences. Design: A cross-sectional KIDSCREEN-52 (by-proxy version) study. Subjects/Patients: The parents of 80 out of 81 children (mean age 13.4 years, SD 2.98; 49 boys, 31 girls; Gross Motor Function Classification System (GMFCS) level 1: 21, 2: 5, 3: 16, 4: 18, 5: 20) agreed to participate. Methods: Two-sample T-tests were used to compare domain scores between groups. Regression analysis was used to identify factors associated with deviant QoL scores. Results: Parents reported significantly higher QoL for the domains of parent relation & home life and school environment. On the other hand significantly lower QoL was reported for the domains of psychical well-being, social support & peers, and social acceptance. Factors associated with deviant QoL scores were lower cognitive levels, less communication skills, and higher GMFCS levels. Conclusion: This study exposed several problem domains of QoL in children with CP living in the Southern part of the Netherlands. Several possible explanations for these findings are given. This information can be used to inform caregivers and service-providers.

The non-celiac gluten sensitivity (NCGS) is a chronic functional gastrointestinal disorder which is very common world wide. The human gut harbors microbiota which has a wide variety of microbial organisms; they are mainly symbiotic and important for well being. However, “dysbiosis” - i.e. an alteration in normal commensal gut microbiome with an increase in pathogenic microbes, impacts homeostasis/health. Dysbiosis in NCGS causes gut inflammation, diarrhea, constipation, visceral hypersensitivity, abdominal pain, dysfunctional metabolic state, and peripheral immune and neuro-immune communication. Thus, immune-mediated gut and extra-gut dysfunctions, due to gluten sensitivity with comorbid diarrhea, may last for decades. A significant proportion of NCGS patients may chronically consume alcohol, non-steroidal anti-inflammatory drugs, and fatty diet, as well as suffer from various comorbid disorders. The above pathophysiological substrate and dysbiosis are underpinned by dysfunctional bidirectional “Gut-Brain Axis” pathway. Pathogenic gut microbiota is known to upregulate gut- and systemic inflammation (due to lipopolysaccharide from pathogenic bacteria and synthesis of pro-inflammatory cytokines); they enhance energy harvest, cause obesity, insulin resistance, and dysfunctional vago-vagal gut-brain axis. Conceivably, the above cascade of pathology may promote various pathophysiological mechanisms, neuroinflammation, and cognitive dysfunction. Hence, dysbiosis, gut inflammation, and chronic dyshomeostasis are of great clinical relevance. It is argued here that we need to be aware of NCGS and its chronic pathophysiological impact. Therapeutic measures including probiotics, vagus nerve stimulation, antioxidants, alpha 7 nicotinic receptor agonists, and corticotropin-releasing factor receptor 1 antagonist may ameliorate neuroinflammation and oxidative stress in NCGS; they may therefore, prevent cognitive dysfunction and vulnerability to Alzheimer’s disease.

Ginkgo biloba extract 761 (EGb 761) is a well-defined extract obtained from Ginkgo biloba leaves according to a standardized method. It has been used extensively for the treatment of diseases related to the central nervous system including neurosensory disturbances, cerebrovascular insufficiency, peripheral vascular disturbances, and degenerative dementia. The potential use of EGb 761 has also been suggested for the treatment of psychiatric disorders such as anxiety and depression, which is discussed in the current review. These disorders constitute a global epidemic with serious economic and social consequences. Current available treatments with synthetic drugs may have some disadvantages and undesired side effects. There are diverse natural extracts that have been used for the treatment of psychiatric disorders due to their therapeutic action and low rate of side effects, such as EGb 761. EGb 761 has the ability to produce neuroprotection due to its chemical composition and the synergy of its components. We describe several neuroprotective mechanisms of action of EGb 761 such as antioxidant effects, modulation of neurotransmission, neuroendocrine regulation, and upregulation of neurotrophic factors, which underlie its potential therapeutic effect on psychiatric disorders. Furthermore, we discuss the therapeutic effects of EGb 761 both in animal models of psychiatric disorders and in clinical studies that include these pathologies. We focus on depression, anxiety, and schizophrenia, as well as the therapeutic action of EGb 761 on dementia in comorbidity with psychiatric disorders. In the current review, we propose the potential use of EGb 761, alone or combined with current medication treatment, for psychiatric disorders.