Bi-allelic NRXN1α deletion in microglia derived from iPSC of an autistic patient increases interleukin-6 production and impairs supporting function on neuronal networking.

Autism spectrum disorder (ASD) is a set of heterogeneous neurodevelopmental conditions, with a highly diverse genetic hereditary component, including altered neuronal circuits, that has an impact on communication skills and behaviours of the affected individuals. Beside the recognised role of neuronal alterations, perturbations of microglia and the associated neuroinflammatory processes have emerged as credible contributors to aetiology and physiopathology of ASD. Mutations in NRXN1, a member of the neurexin family of cell-surface receptors that bind neuroligin, have been associated to ASD. NRXN1 is known to be expressed by neurons where it facilitates synaptic contacts, but it has also been identified in glial cells including microglia. Asserting the impact of ASD-related genes on neuronal versus microglia functions has been challenging. Here, we present an ASD subject-derived induced pluripotent stem cells (iPSC)-based in vitro system to characterise the effects of the ASD-associated NRXN1 gene deletion on neurons and microglia, as well as on the ability of microglia to support neuronal circuit formation and function. Using this approach, we demonstrated that NRXN1 deletion, impacting on the expression of the alpha isoform (NRXN1α), in microglia leads to microglial alterations and release of IL6, a pro-inflammatory interleukin associated with ASD. Moreover, microglia bearing the NRXN1α-deletion, lost the ability to support the formation of functional neuronal networks. The use of recombinant IL6 protein on control microglia-neuron co-cultures or neutralizing antibody to IL6 on their NRXN1α-deficient counterparts, supported a direct contribution of IL6 to the observed neuronal phenotype. Altogether, our data suggest that, in addition to neurons, microglia are also negatively affected by NRXN1α-deletion, and this significantly contributes to the observed neuronal circuit aberrations.

The Threat Posed by Environmental Contaminants on Neurodevelopment: What Can We Learn from Neural Stem Cells?

Exposure to chemicals may pose a greater risk to vulnerable groups, including pregnant women, fetuses, and children, that may lead to diseases linked to the toxicants' target organs. Among chemical contaminants, methylmercury (MeHg), present in aquatic food, is one of the most harmful to the developing nervous system depending on time and level of exposure. Moreover, certain man-made PFAS, such as PFOS and PFOA, used in commercial and industrial products including liquid repellants for paper, packaging, textile, leather, and carpets, are developmental neurotoxicants. There is vast knowledge about the detrimental neurotoxic effects induced by high levels of exposure to these chemicals. Less is known about the consequences that low-level exposures may have on neurodevelopment, although an increasing number of studies link neurotoxic chemical exposures to neurodevelopmental disorders. Still, the mechanisms of toxicity are not identified. Here we review in vitro mechanistic studies using neural stem cells (NSCs) from rodents and humans to dissect the cellular and molecular processes changed by exposure to environmentally relevant levels of MeHg or PFOS/PFOA. All studies show that even low concentrations dysregulate critical neurodevelopmental steps supporting the idea that neurotoxic chemicals may play a role in the onset of neurodevelopmental disorders.

Sex Differences in Long-term Outcome of Prenatal Exposure to Excess Glucocorticoids-Implications for Development of Psychiatric Disorders.

Exposure to prenatal insults, such as excess glucocorticoids (GC), may lead to pathological outcomes, including neuropsychiatric disorders. The aim of the present study was to investigate the long-term effects of in utero exposure to the synthetic GC analog dexamethasone (Dex) in adult female offspring. We monitored spontaneous activity in the home cage under a constant 12 h/12 h light/dark cycle, as well as the changes following a 6-h advance of dark onset (phase shift). For comparison, we re-analysed data previously recorded in males. Dex-exposed females were spontaneously more active, and the activity onset re-entrained slower than in controls. In contrast, Dex-exposed males were less active, and the activity onset re-entrained faster than in controls. Following the phase shift, control females displayed a transient reorganisation of behaviour in light and virtually no change in dark, while Dex-exposed females showed limited variations from baseline in both light and dark, suggesting weaker photic entrainment. Next, we ran bulk RNA-sequencing in the suprachiasmatic nucleus (SCN) of Dex and control females. SPIA pathway analysis of ~ 2300 differentially expressed genes identified significantly downregulated dopamine signalling, and upregulated glutamate and GABA signalling. We selected a set of candidate genes matching the behaviour alterations and found consistent differential regulation for ~ 73% of tested genes in SCN and hippocampus tissue samples. Taken together, our data highlight sex differences in the outcome of prenatal exposure to excess GC in adult mice: in contrast to depression-like behaviour in males, the phenotype in females, defined by behaviour and differential gene expression, is consistent with ADHD models.

Apoptosis in seborrheic keratoses: an open door to a new dermoscopic score.

The aetiology of seborrheic keratoses (SK), the most common benign epithelial tumours, and any relationship with malignancy are not yet known. As a protective anti-cancer mechanism, apoptosis reflects cellular loss as a reaction to proliferative activity. The objective of this study was to quantify apoptosis in different SK types (acanthotic, hyperkeratotic, reticulated, irritated and clonal) and correlate the dermoscopic picture with apoptosis rate. After a qualitative and quantitative analysis of dermoscopic images, we defined a new quantitative dermoscopic score (C3V2F, crypts, millia cysts, colours, hairpin vessels, irregular vessels, fissures) from 0 to 22, which enabled us to establish cut-offs correlating with apoptosis rates. All five SK forms were associated with lower apoptosis rates compared with normal skin. A C3V2F score >10 and greater number of crypts and colours reflected a higher apoptosis rate, which implies a benign character of evolution. In contrast, the presence of irregular vessels on more than 50% of the lesion surface implied a lower rate of apoptosis and probably associated with a risk of malignant transformation. On the basis of dermoscopic information, we used multiple regression to establish a model for estimating the rate of apoptosis with a 0.7 prediction interval (approximately 1S.D.). The new C3V2F score could be valuable for the clinical evaluation of possible SK prognosis and decisions regarding excision.

Morphological and behavioral changes induced by transgenic overexpression of interleukin-1ra in the brain.

Interleukin-1 (IL-1) has a peak of expression in the brain in a period of maximal network reorganization and then virtually disappears from the normal adult brain. The aim of our study was to identify phenotypical alterations induced by chronically blocking IL-1 signalling. We used homozygous transgenic mice overexpressing human soluble IL-1ra and age-matched wild-type mice. We used littermates from litters obtained by mating heterozygous transgenic progenitors, and animals with predetermined genotype (nonlittermates). In littermates, the genotype was identified after the experiments had been completed. The mice were tested at the ages of 6 and 12 months with a battery of tests, including dark-light preference, footprint/gait analysis, and analysis of motor performance during swimming. MR imaging was performed on formalin-fixed brains; total and relative volumes of cortical and subcortical structures were estimated stereologically on the acquired images. Multivariate data analysis (PLS-DA) of the behavioral data showed separation between nonlittermate wild-type and transgenic mice at both 6 and 12 months, whereas the littermates displayed a more homogenous behavioral profile. The PLS-DA model for brain morphology showed a clear separation between wild-type and transgenic mice as well as between transgenic littermates and nonlittermates. Regression analysis by means of partial least squares (PLS) showed that the brain morphology accounts for the behavioral profile in a significant proportion (16.9%). In conclusion, we show that IL-1 signalling is important for normal development of the brain, and the initial alteration resulting from prenatal exposure to IL-1ra can be recovered provided that the IL-1 signalling pathway is intact.

In utero exposure to dexamethasone causes a persistent and age-dependent exacerbation of the neurotoxic effects and glia activation induced by MDMA in dopaminergic brain regions of C57BL/6J mice.

Clinical and preclinical evidence indicates that prenatal exposure to glucocorticoids may induce detrimental effects in the offspring, including reduction in fetal growth and alterations in the CNS. On this basis, the present study investigated whether in utero exposure to high levels of glucocorticoids is a risk factor that may lead to an exacerbation of the central noxious effects induced by psychoactive drugs consumed later in life. To this end, pregnant C57BL6/J dams were treated with dexamethasone (DEX, 0.05 mg/kg per day) from gestational day 14 until delivery. Thereafter, the male offspring were evaluated to ascertain the magnitude of dopaminergic damage, astrogliosis and microgliosis elicited in the nigrostriatal tract by the amphetamine-related drug 3,4--methylenedioxymethamphetamine (MDMA, 4 × 20 mg/kg, 2 h apart, sacrificed 48 h later) administered at either adolescence or adulthood. Immunohistochemistry was performed in the substantia nigra pars compacta (SNc) and striatum, to evaluate dopaminergic degeneration by measuring tyrosine hydroxylase (TH), as well as astrogliosis and microgliosis by measuring glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (IBA-1), respectively. Moreover, immunohistochemistry was used to ascertain the co-localization of IBA-1 with either the pro-inflammatory interleukin (IL) IL-1ß or the anti-inflammatory IL IL-10, in order to determine the microglial phenotype. In utero administration of DEX induced dopaminergic damage by decreasing the density of TH-positive fibers in the striatum, although only in adult mice. MDMA administration induced dopaminergic damage and glia activation in the nigrostriatal tract of adolescent and adult mice. Mice exposed to DEX in utero and treated with MDMA later in life showed a more pronounced loss of dopaminergic neurons (adolescent mice) and astrogliosis (adolescent and adult mice) in the SNc, compared with control mice. These results suggest that prenatal exposure to glucocorticoids may induce an age-dependent and persistent increase in the susceptibility to central toxicity of amphetamine-related drugs used later in life.

Altered expression of claudin family proteins in Alzheimer's disease and vascular dementia brains.

Claudins (Cls) are a multigene family of transmembrane proteins with different tissue distribution, which have an essential role in the formation and sealing capacity of tight junctions (TJs). At the level of the blood-brain barrier (BBB), TJs are the main molecular structures which separate the neuronal milieu from the circulatory space, by a restriction of the paracellular flow of water, ions and larger molecules into the brain. Different studies suggested recently significant BBB alterations in both vascular and degenerative dementia types. In a previous study we found in Alzheimer's disease (AD) and vascular dementia (VaD) brains an altered expression of occludin, a molecular partner of Cls in the TJs structure. Therefore in this study, using an immunohistochemical approach, we investigated the expression of Cl family proteins (Cl-2, Cl-5 and Cl-11) in frontal cortex of aged control, AD and VaD brains. To estimate the number of Cl-expressing cells, we applied a random systematic sampling and the unbiased optical fractionator method. We found selected neurons, astrocytes, oligodendrocytes and endothelial cells expressing Cl-2, Cl-5 and Cl-11 at detectable levels in all cases studied. We report a significant increase in ratio of neurons expressing Cl-2, Cl-5 and Cl-11 in both AD and VaD as compared to aged controls. The ratio of astrocytes expressing Cl-2 and Cl-11 was significantly higher in AD and VaD as compared to aged controls. The ratio of oligodendrocytes expressing Cl-11 was significantly higher in AD and the ratio of oligodendrocytes expressing Cl-2 was significantly higher in VaD as compared to aged controls. Within the cerebral cortex, Cls were selectively expressed by pyramidal neurons, which are the ones responsible for cognitive processes and affected by AD pathology. Our findings suggest a new function of Cl family proteins which might be linked to response to cellular stress.

A randomized controlled study of weighted chain blankets for insomnia in psychiatric disorders.

STUDY OBJECTIVES: This study aimed to evaluate the effect of weighted chain blankets on insomnia and sleep-related daytime symptoms for patients with major depressive disorder, bipolar disorder, generalized anxiety disorder, and attention deficit hyperactivity disorder. METHODS: One hundred twenty patients were randomized (1:1) to either a weighted metal chain blanket or a light plastic chain blanket for 4 weeks. The outcome was evaluated using the Insomnia Severity Index as primary outcome measure and day and night diaries, Fatigue Symptom Inventory, and Hospital Anxiety and Depression Scale as secondary outcome measures. Sleep and daytime activity levels were evaluated by wrist actigraphy. RESULTS: At 4 weeks, there was a significant advantage in Insomnia Severity Index ratings of the weighted blanket intervention over the light blanket (P < .001) with a large effect size (Cohen's d 1.90). The intervention by the weighted blanket resulted in a significantly better sleep-maintenance, a higher daytime activity level, and reduced daytime symptoms of fatigue, depression, and anxiety. No serious adverse events occurred. During a 12-month open follow-up phase of the study, participants continuing to use weighted blankets maintained the effect on sleep, while patients switching from a light to a weighted blanket experienced an effect on Insomnia Severity Index ratings similar to that of participants using the weighted blanket from the beginning. CONCLUSIONS: Weighted chain blankets are an effective and safe intervention for insomnia in patients with major depressive disorder, bipolar disorder, generalized anxiety disorder, or attention deficit hyperactivity disorder, also improving daytime symptoms and levels of activity. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Controlled Study of Chain Blanket for Insomnia; URL: https://clinicaltrials.gov/ct2/show/NCT03546036; Identifier: NCT03546036.

Growth dependence on insulin-like growth factor-1 during the ketogenic diet.

PURPOSE: To examine the influence of the ketogenic diet (KD) on linear growth and insulin-like growth factor I (IGF-I) levels in children with pharmacotherapy-resistant epilepsy. METHODS: A prospective study was designed to evaluate growth, serum IGF-I levels, blood beta-hydroxybutyric acid (beta-OHB), and seizure frequency before and during KD in 22 children (median age 5.5 years). Growth was assessed by measurements of weight, height, body mass index (BMI), and height velocity. Standard deviation scores (SDS) were calculated for all measured parameters as well as for serum IGF-I to eliminate the influence of age- and sex-related differences among patients. RESULTS: Fourteen of the 22 patients responded to the KD. Weight, height, BMI, and height velocity decreased significantly during the KD. We found that the KD had profound influence on growth and IGF-I levels. No correlation was found between seizure response and growth alterations. Height velocity correlated negatively with beta-OHB during the KD. The slope of the regression of height velocity against IGF-I decreased significantly during the KD. CONCLUSIONS: Height velocity was most affected in those with pronounced ketosis, which implies that, in clinical practice, the level of ketosis should be related to outcomes in seizure response and growth. Our data indicate that growth disturbances and the decreased sensitivity of growth to similar IGF-I levels during KD are independent of seizure reduction. The metabolic status induced by KD may be the mechanism underlying both alterations of linear growth and seizure reduction.

Spinal cord injury in zebrafish induced by near-infrared femtosecond laser pulses.

BACKGROUND: The spinal cord is composed of a large number of cells that interact to allow the organism to function. To perform detail studies of cellular processes involved in spinal cord injury (SCI), one must use repeatable and specific methods to target and injure restricted areas of the spinal cord. NEW METHOD: We propose a robust method to induce SCI in zebrafish by laser light. With a 2-photon microscope equipped with a femtosecond near-infrared pump laser, we explored the effects of laser beam exposure time, area, and intensity to induce precise and repeatable SCI with minimized collateral damage to neighboring cells. RESULTS: Through behavioral studies in zebrafish larvae, we assessed the functional outcome of intensive laser light directed at the spinal cord. Our experiments revealed that a laser pulse with wavelength 800 nm, duration 2.6 ms, and light intensity 390 mW was sufficient to induce controlled cell death in a single cell or a spinal cord segment. Collateral damage was observed if cells were exposed to laser pulses exceeding 470 mW. With these settings, we could induce precise and repeatable SCI in zebrafish larvae, resulting in loss of motor and sensory function. COMPARISON WITH EXISTING METHOD(S): Our method offers a simple and more controlled setting to induce SCI in zebrafish. We describe how the near-infrared femtosecond laser should be adjusted for achieving optimal results with minimal collateral damage. CONCLUSIONS: We present a precise and robust method for inducing SCI in zebrafish with single-cell resolution using femtosecond near-infrared laser pulses.

Desipramine restores the alterations in circadian entrainment induced by prenatal exposure to glucocorticoids.

Alterations in circadian rhythms are closely linked to depression, and we have shown earlier that progressive alterations in circadian entrainment precede the onset of depression in mice exposed in utero to excess glucocorticoids. The aim of this study was to investigate whether treatment with the noradrenaline reuptake inhibitor desipramine (DMI) could restore the alterations in circadian entrainment and prevent the onset of depression-like behavior. C57Bl/6 mice were exposed to dexamethasone (DEX-synthetic glucocorticoid analog, 0.05 mg/kg/day) between gestational day 14 and delivery. Male offspring aged 6 months (mo) were treated with DMI (10 mg/kg/day in drinking water) for at least 21 days before behavioral testing. We recorded spontaneous activity using the TraffiCage™ system and found that DEX mice re-entrained faster than controls after an abrupt advance in light-dark cycle by 6 h, while DMI treatment significantly delayed re-entrainment. Next we assessed the synchronization of peripheral oscillators with the central clock (located in the suprachiasmatic nucleus-SCN), as well as the mechanisms required for entrainment. We found that photic entrainment of the SCN was apparently preserved in DEX mice, but the expression of clock genes in the hippocampus was not synchronized with the light-dark cycle. This was associated with downregulated mRNA expression for arginine vasopressin (AVP; the main molecular output entraining peripheral clocks) in the SCN, and for glucocorticoid receptor (GR; required for the negative feedback loop regulating glucocorticoid secretion) in the hippocampus. DMI treatment restored the mRNA expression of AVP in the SCN and enhanced GR-mediated signaling by upregulating GR expression and nuclear translocation in the hippocampus. Furthermore, DMI treatment at 6 mo prevented the onset of depression-like behavior and the associated alterations in neurogenesis in 12-mo-old DEX mice. Taken together, our data indicate that DMI treatment enhances GR-mediated signaling and restores the synchronization of peripheral clocks with the SCN and support the hypothesis that altered circadian entrainment is a modifiable risk factor for depression.

NRXN1 Deletion and Exposure to Methylmercury Increase Astrocyte Differentiation by Different Notch-Dependent Transcriptional Mechanisms.

Controversial evidence points to a possible involvement of methylmercury (MeHg) in the etiopathogenesis of autism spectrum disorders (ASD). In the present study, we used human neuroepithelial stem cells from healthy donors and from an autistic patient bearing a bi-allelic deletion in the gene encoding for NRXN1 to evaluate whether MeHg would induce cellular changes comparable to those seen in cells derived from the ASD patient. In healthy cells, a subcytotoxic concentration of MeHg enhanced astroglial differentiation similarly to what observed in the diseased cells (N1), as shown by the number of GFAP positive cells and immunofluorescence signal intensity. In both healthy MeHg-treated and N1 untreated cells, aberrations in Notch pathway activity seemed to play a critical role in promoting the differentiation toward glia. Accordingly, treatment with the established Notch inhibitor DAPT reversed the altered differentiation. Although our data are not conclusive since only one of the genes involved in ASD is considered, the results provide novel evidence suggesting that developmental exposure to MeHg, even at subcytotoxic concentrations, induces alterations in astroglial differentiation similar to those observed in ASD.

Blunted neurogenesis and gliosis due to transgenic overexpression of human soluble IL-1ra in the mouse.

Interleukin-1 (IL-1) is one of the most important cytokines in neuroinflammation, in acute conditions as well as during natural ageing and neurodegenerative disorders. Using a transgenic mouse strain with brain-directed overexpression of IL-1 receptor antagonist (Tg hsIL-1ra), we show that blocking IL-1 receptor-mediated activity resulted in abolishing the alterations in neurogenesis in response to acute and chronic neuroinflammation. In addition, using a novel approach to quantifying glial activation, we show that expression of the astrocyte cytoskeletal marker glial fibrillary acidic protein (GFAP) following kainic acid (KA)-induced seizures or during ageing did not change in Tg hsIL-1ra animals. Nevertheless, the astrocyte morphology showed major alterations, consisting of fragmentation of the processes in Tg hsIL-1ra mice. Similarly, although there was a higher degree of basal microglial activation in the transgenic mice than wild-type animals, there was no change following KA-induced seizures or with ageing. Taken together, our results indicate that IL-1 is crucial for the adaptability of the brain to acute and chronic neuroinflammation.

Alpha-MSH rescues neurons from excitotoxic cell death.

This study investigates the effects of alpha-melanocyte-stimulating hormone (alpha-MSH), on neurodegeneration, gliosis and changes in the neurotrophic protein brain-derived neurotrophic factor (BDNF) and in pro-inflammatory cytokines, following kainic acid (KA)-induced excitotoxic damage in the rat. Male Sprague-Dawley rats were treated with alpha-MSH (intraperitoneally, i.p.) at 20 min, and 24 and 48 h following administration of 10 mg/kg KA (i.p.). The animals were sacrificed at 30 min, 4 h, 24 h and 72 h after KA-administration and the levels of interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) were analysed in samples of hippocampus and hypothalamus. Levels of BDNF were analysed in the hippocampus. Stereological quantification showed a markedly reduced number of viable neurons in the CA1 pyramidal cell layer upon KA-administration as compared to animals injected with vehicle (p < 0.05, 79,587 +/- 25,554 vs. 145,254 +/- 27,871). The number of viable neurons upon administration of alpha-MSH was significantly higher than upon KA alone (p < 0.05, 119,776 +/- 33,158, KA+alpha-MSH vs. 79,587 +/- 27,554, KA + Saline). Astrocyte activation due to the KA-induced excitotoxicity was reduced, and the KA-induced increase in IL-1beta levels was delayed by the treatment with alpha-MSH. In conclusion, the degree of reduction in cell viability in the hippocampus CA1 pyramidal cell layer upon KA-induced excitotoxicity was similar to that seen previously upon global cerebral ischaemia. Furthermore, the administration of alpha-MSH resulted in a similar increase in cell viability, supporting the hypothesis that administration of alpha-MSH has rescuing effects on neurons subjected to excitotoxic insults.

Inflammation in the nervous system--physiological and pathophysiological aspects.

There is ample evidence for the occurrence of inflammatory processes in most major neurodegenerative disorders, both in acute conditions such as traumatic brain injury and stroke, and in chronic disorders such as Alzheimer's disease, epilepsy, amyotrophic lateral sclerosis and Parkinson's disease. Studies on inflammatory factors such as pro- and antiinflammatory cytokines in experimental models of neurodegenerative disorders suggest that they are not merely bystanders, but may be involved in the neurodegenerative process. In addition, there are findings indicating that inflammatory factors may have beneficial effects on the nervous system, particularly during development of the nervous system. The challenge is to understand when, where and during which circumstances inflammation and inflammatory factors are positive or negative for neuronal survival and functioning. Some of our studies on cytokines, particularly the interleukin-1 system, are summarised and discussed in relation to neurodegeneration, cognition, and temperature changes.

Depressive-like phenotype induced by prenatal dexamethasone in mice is reversed by desipramine.

Exposure to prenatal insults has been associated with an increased risk for neuropsychiatric disorders, including depression, but the mechanisms are still poorly understood. Persistent alterations of the HPA axis feedback mechanism as well as adult impaired neurogenesis are believed to play a relevant role in the etiology of depression. In addition, growing evidence points at epigenetic reprogramming as a key factor. We have previously shown that prenatal exposure to the synthetic glucocorticoid dexamethasone (DEX) impairs neurogenesis and leads to late onset of depression-like behavior that does not respond to the SSRI antidepressant fluoxetine (FLX). The aims of this study were to assess the effect of DEX prenatal exposure on the morphology of hippocampal granule neurons and on the expression of genes related to plasticity; and to test whether the SNRI antidepressant desipramine (DMI), unlike FLX, could counteract the effect of prenatal-DEX. C57Bl/6 mice were exposed to DEX (0.05 mg/kg/day) in utero and received intra-hippocampal injection of GFP expressing retroviral vector for labeling of newborn granule cells at eleven months. By twelve months, DEX mice showed depression-like behavior associated with decreased neurogenesis and morphological alterations of the newborn granule cells in the dentate gyrus (DG). Furthermore DEX mice displayed altered expression of genes controlling neurogenesis and neuronal morphology, such as Cdkn1c, p16, TrkB, DISC1 and Reelin. Chronic treatment with DMI led to a significant decrease in immobility time in the forced swim test. In addition, DMI restored neurogenesis, neuronal morphology in the DG, as well as the expression of all related genes. Our results suggest that (1) prenatal DEX induces early and persistent reprogramming effects resulting in altered neurogenesis and neuronal morphology; and (2) DMI treatment reverses DEX-induced depression by restoring the expression of genes relevant to neuronal plasticity.

Long-term consequences of prenatal stress and neurotoxicants exposure on neurodevelopment.

There is a large consensus that the prenatal environment determines the susceptibility to pathological conditions later in life. The hypothesis most widely accepted is that exposure to insults inducing adverse conditions in-utero may have negative effects on the development of target organs, disrupting homeostasis and increasing the risk of diseases at adulthood. Several models have been proposed to investigate the fetal origins of adult diseases, but although these approaches hold true for almost all diseases, particular attention has been focused on disorders related to the central nervous system, since the brain is particularly sensitive to alterations of the microenvironment during early development. Neurobiological disorders can be broadly divided into developmental, neurodegenerative and neuropsychiatric disorders. Even though most of these diseases share genetic risk factors, the onset of the disorders cannot be explained solely by inheritance. Therefore, current understanding presumes that the interactions of environmental input, may lead to different disorders. Among the insults that can play a direct or indirect role in the development of neurobiological disorders are stress, infections, drug abuse, and environmental contaminants. Our laboratories have been involved in the study of the neurobiological impact of gestational stress on the offspring (Dr. Antonelli's lab) and on the effect of gestational exposure to toxicants, mainly methyl mercury (MeHg) and perfluorinated compounds (PFCs) (Dr. Ceccatelli's lab). In this focused review, we will review the specialized literature but we will concentrate mostly on our own work on the long term neurodevelopmental consequences of gestational exposure to stress and neurotoxicants.

alpha-Melanocyte-stimulating hormone is neuroprotective in rat global cerebral ischemia.

The aim of the study was to investigate the effects of alpha-melanocyte-stimulating hormone (alpha-MSH), a tridecapeptide derived from proopiomelanocortin (POMC), on the neurodegeneration following global cerebral ischemia and reperfusion in the rat. The biological activities of alpha-MSH include inhibition of inflammatory responses and anti-pyretic effects. Male Sprague-Dawley rats were subjected to four-vessel occlusion (4-VO) global cerebral ischemia followed by reperfusion, and treated with alpha-MSH (intraperitoneally, i.p.) at 30 min, and 24, 48, 72 and 96 h post-ischemia. Stereological quantification of the pyramidal cells in the CA1 area of the hippocampus showed that the number of viable neurons in ischemic rats was 96,945+/-18,610 (means+/-SD) as compared to 183,156+/-49,935 in sham-operated rats (P<0.05). The number of viable neurons after treatment of ischemic rats with alpha-MSH was 162,829+/-34,757, i.e. significantly different from the number of viable neurons in ischemic rats injected with saline (P<0.01). Astrocyte proliferation due to the ischemic insult was markedly reduced by the treatment with alpha-MSH, and the loss in body weight was reduced by alpha-MSH. In conclusion, post-ischemic administration of alpha-MSH was found to provide neuroprotection in the CA1 pyramidal cell layer in the hippocampus, concomitant with a reduction in glial activation, indicating that alpha-MSH or mimetics thereof may have a potential in the treatment of stroke or other neurodegenerative diseases. Further studies will be required to define the post-ischemic time window for administration of alpha-MSH.