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1.  Food-derived opioid peptides inhibit cysteine uptake with redox and epigenetic consequences 
Dietary interventions like gluten-free and casein-free diets have been reported to improve intestinal, autoimmune and neurological symptoms in patients with a variety of conditions; however, the underlying mechanism of benefit for such diets remains unclear. Epigenetic programming, including CpG methylation and histone modifications, occurring during early postnatal development can influence the risk of disease in later life, and such programming may be modulated by nutritional factors such as milk and wheat, especially during the transition from a solely milk-based diet to one that includes other forms of nutrition. The hydrolytic digestion of casein (a major milk protein) and gliadin (a wheat-derived protein) releases peptides with opioid activity, and in the present study, we demonstrate that these food-derived proline-rich opioid peptides modulate cysteine uptake in cultured human neuronal and gastrointestinal (GI) epithelial cells via activation of opioid receptors. Decreases in cysteine uptake were associated with changes in the intracellular antioxidant glutathione and the methyl donor S-adenosylmethionine. Bovine and human casein-derived opioid peptides increased genome-wide DNA methylation in the transcription start site region with a potency order similar to their inhibition of cysteine uptake. Altered expression of genes involved in redox and methylation homeostasis was also observed. These results illustrate the potential of milk- and wheat-derived peptides to exert antioxidant and epigenetic changes which may be particularly important during the postnatal transition from placental to GI nutrition. Differences between peptides derived from human and bovine milk may contribute to developmental differences between breastfed and formula-fed infants. Restricted antioxidant capacity, caused by wheat- and milk-derived opioid peptides, may predispose susceptible individuals to inflammation and systemic oxidation, partly explaining the benefits of gluten-free or casein-free diets.
PMCID: PMC4157943  PMID: 25018147
Glutathione; casomorphin; gliadin; autism spectrum disorder; schizophrenia; celiac disease; gluten-free/casein-free diet
2.  Epigenetic effects of casein-derived opioid peptides in SH-SY5Y human neuroblastoma cells 
Casein-free, gluten-free diets have been reported to mitigate some of the inflammatory gastrointestinal and behavioral traits associated with autism, but the mechanism for this palliative effect has not been elucidated. We recently showed that the opioid peptide beta-casomorphin-7, derived from bovine (bBCM7) milk, decreases cysteine uptake, lowers levels of the antioxidant glutathione (GSH) and decreases the methyl donor S-adenosylmethionine (SAM) in both Caco-2 human GI epithelial cells and SH-SY5Y human neuroblastoma cells. While human breast milk can also release a similar peptide (hBCM-7), the bBCM7 and hBCM-7 vary greatly in potency; as the bBCM-7 is highly potent and similar to morphine in it's effects. Since SAM is required for DNA methylation, we wanted to further investigate the epigenetic effects of these food-derived opioid peptides. In the current study the main objective was to characterize functional pathways and key genes responding to DNA methylation effects of food-derived opioid peptides.
SH-SY5Y neuroblastoma cells were treated with 1 μM hBCM7 and bBCM7 and RNA and DNA were isolated after 4 h with or without treatment. Transcriptional changes were assessed using a microarray approach and CpG methylation status was analyzed at 450,000 CpG sites. Functional implications from both endpoints were evaluated via Ingenuity Pathway Analysis 4.0 and KEGG pathway analysis was performed to identify biological interactions between transcripts that were significantly altered at DNA methylation or transcriptional levels (p < 0.05, FDR <0.1).
Here we show that hBCM7 and bBCM7, as well as morphine, cause epigenetic changes affecting gene pathways related to gastrointestinal disease and inflammation. These epigenetic consequences exhibited the same potency order as opiate inhibition of cysteine uptake insofar as hBCM7 was less potent than bBCM7, which was less potent than morphine.
Our findings indicate that epigenetic effects of milk-derived opiate peptides may contribute to GI dysfunction and inflammation in sensitive individuals. While the current study was performed using SH-SY5Y neuronal cellular models, similar actions on other cells types might combine to cause symptoms of intolerance. These actions may provide a potential contributing mechanism for the beneficial effects of a casein-free diet in alleviating gastrointestinal symptoms in neurological conditions including autism and other conditions. Lastly, our study also contributes to the evolving awareness of a “gut-brain connection”.
Electronic supplementary material
The online version of this article (doi:10.1186/s12986-015-0050-1) contains supplementary material, which is available to authorized users.
PMCID: PMC4673759  PMID: 26664459
Epigenetics; Gluten free casein free diet; Autism; Glutathione; Gastrointestinal; Inflammation
3.  Intracellular and Extracellular Redox Status and Free Radical Generation in Primary Immune Cells from Children with Autism 
Autism Research and Treatment  2011;2012:986519.
The modulation of the redox microenvironment is an important regulator of immune cell activation and proliferation. To investigate immune cell redox status in autism we quantified the intracellular glutathione redox couple (GSH/GSSG) in resting peripheral blood mononuclear cells (PBMCs), activated monocytes and CD4 T cells and the extracellular cysteine/cystine redox couple in the plasma from 43 children with autism and 41 age-matched control children. Resting PBMCs and activated monocytes from children with autism exhibited significantly higher oxidized glutathione (GSSG) and percent oxidized glutathione equivalents and decreased glutathione redox status (GSH/GSSG). In activated CD4 T cells from children with autism, the percent oxidized glutathione equivalents were similarly increased, and GSH and GSH/GSSG were decreased. In the plasma, both glutathione and cysteine redox ratios were decreased in autistic compared to control children. Consistent with decreased intracellular and extracellular redox status, generation of free radicals was significantly elevated in lymphocytes from the autistic children. These data indicate primary immune cells from autistic children have a more oxidized intracellular and extracellular microenvironment and a deficit in glutathione-mediated redox/antioxidant capacity compared to control children. These results suggest that the loss of glutathione redox homeostasis and chronic oxidative stress may contribute to immune dysregulation in autism.
PMCID: PMC3420377  PMID: 22928106
4.  Volatile anesthetics attenuate oxidative stress-reduced activity of glutamate transporter type 3 
Anesthesia and analgesia  2009;109(5):1506-1510.
Volatile anesthetics enhance the activity of glutamate transporter type 3 (also called excitatory amino acid transporter type 3, EAAT3), the major neuronal EAAT. In addition to glutamate, EAAT3 can also uptake L-cysteine, the rate-limiting substrate for the synthesis of glutathione. Our previous study showed that oxidative stress inhibited glutamate-induced EAAT3 activity. We determined whether oxidative stress would reduce L-cysteine-induced EAAT3 activity and whether this reduction would be attenuated by volatile anesthetics.
Rat EAAT3 was expressed in Xenopus oocytes. L-glutamate- and L-cysteine-induced membrane currents were recorded using the two-electrode voltage clamp technique. The peak current was quantified to reflect the amount of transported substrates because transport of substrates via EAATs is electrogenic.
Exposure of oocytes to 5 mM tert-butyl hydroperoxide, an organic oxidant, for 10 min reduced the Vmax, but did not affect the Km, of EAAT3 for L-cysteine. The volatile anesthetics isoflurane, sevoflurane and desflurane at concentrations from 1 to 3% attenuated the tert-butyl hydroperoxide-reduced EAAT3 activity for L-glutamate and L-cysteine.
Our results suggest that volatile anesthetics preserve EAAT3 function to transport L-glutamate and L-cysteine under oxidative stress, which may be a mechanism for the neuroprotective effects of volatile anesthetics.
PMCID: PMC2773695  PMID: 19843789
5.  Habituation of exploratory behaviour in VPA rats: animal model of autism 
Interdisciplinary Toxicology  2013;6(4):222-227.
Autism is a neurodevelopmental disorder with multifactorial aetiology, represented as impairment in social behaviour, communication and the occurrence of repetitive activities, which can be observed in the early life. The core features are frequently accompanied by other manifestations, including limited environmental exploration. The aim of the presented study, realised on an animal model of autism – VPA rats, i.e. animals prenatally affected with valproic acid on gestation day 12.5, was to investigate the habituation process of exploratory activity (manifested by a gradual decrease in the intensity of locomotor activity), which reflects the stage of the central nervous system. VPA rats were tested in open-field in three developmental periods – weaning (postnatal day 21 – PND 21), puberty (PND 42) and adulthood (PND 72). In each period of ontogenesis, the rapidity of habituation was evaluated by using the method of linear regression. Compared to controls, VPA rats showed a significant decrease in the intensity and an increase in the rapidity of exploratory activity habituation during puberty and adulthood. Our results indicate that the animal model of autism, i.e. VPA rats, showed disabilities in the development of the nervous system. These findings can help confirm not only the validity of this animal model of autism but can also help better understand neuronal changes in humans with autism.
PMCID: PMC3945762  PMID: 24678262
autism; animal model; VPA rats; exploratory behaviour; habituation
6.  Metabolic endophenotype and related genotypes are associated with oxidative stress in children with autism 
Autism is a behaviorally-defined neurodevelopmental disorder usually diagnosed in early childhood that is characterized by impairment in reciprocal communication and speech, repetitive behaviors, and social withdrawal. Although both genetic and environmental factors are thought to be involved, none have been reproducibly identified. The metabolic phenotype of an individual reflects the influence of endogenous and exogenous factors on genotype. As such, it provides a window through which the interactive impact of genes and environment may be viewed and relevant susceptibility factors identified. Although abnormal methionine metabolism has been associated with other neurologic disorders, these pathways and related polymorphisms have not been evaluated in autistic children. Plasma levels of metabolites in methionine transmethylation and transsulfuration pathways were measured in 80 autistic and 73 control children. In addition, common polymorphic variants known to modulate these metabolic pathways were evaluated in 360 autistic children and 205 controls. The metabolic results indicated that plasma methionine and the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH), an indicator of methylation capacity, were significantly decreased in the autistic children relative to age-matched controls. In addition, plasma levels of cysteine, glutathione, and the ratio of reduced to oxidized glutathione, an indication of antioxidant capacity and redox homeostasis, were significantly decreased. Differences in allele frequency and/or significant gene-gene interactions were found for relevant genes encoding the reduced folate carrier (RFC 80G>A), transcobalamin II (TCN2 776G>C), catechol-O-methyltransferase (COMT 472G>A), methylenetetrahydrofolate reductase (MTHFR 677C>T and 1298A>C), and GST M1. We propose that an increased vulnerability to oxidative stress (endogenous or environmental) may contribute to the development and clinical manifestations of autism.
PMCID: PMC2610366  PMID: 16917939
autism; oxidative stress; genotype; glutathione; methionine
7.  Effect of Maternal Lipopolysaccharide Administration on the Development of Dopaminergic Receptors and Transporter in the Rat Offspring 
PLoS ONE  2013;8(1):e54439.
Epidemiological evidence supports that maternal infection during gestation are notable risk factors for developmental mental illnesses including schizophrenia and autism. In prenatal lipopolysaccharide (LPS) model of immune activation in rats, the offspring exhibit significant impairments in behaviors mediated by central dopamine (DA) system. This study aimed to examine the temporal and regional pattern of postnatal DA development in the male offspring of pregnant Sprague-Dawley rats administered with 100 µg/kg LPS or saline at gestational days 15/16. Using ligand autoradiography, D1 and D2 dopamine receptors (D1R, D2R) and dopamine transporter (DAT) binding levels were measured in the prefrontal cortex (PFC) and sub cortical regions (dorsal striatum and nucleus accumbens core and shell) at pre pubertal (P35) and post pubertal ages (P60). We found a significant decrease in D2R ligand [3H] YM-90151-2 binding in the medial PFC (mPFC) in prenatal LPS-treated animals at P35 and P60 compared to respective saline groups. The decrease in D2R levels was not observed in the striatum or accumbens of maternal LPS-treated animals. No significant changes were observed in [3H] SCH23390 binding to D1R. However, the level of [125I] RTI-121 binding to DAT was selectively reduced in the nucleus accumbens core and shell at P35 in the prenatal LPS group. Immunohistochemical analysis showed that number of D2R immunopositive cells in infralimbic/prelimbic (IL/PL) part of mPFC was significantly reduced in the LPS group at P60. Prenatal LPS treatment did not significantly affect either the total number of mature neurons or parvalbumin (PV)-immunopositive interneurons in this region. However the number of PV and D2R co-labeled neurons was significantly reduced in the IL/PL subregion of PFC of LPS treated animals. Our data suggests D2R deficit in the PFC and PV interneurons may be relevant to understanding mechanisms of cortical dysfunctions described in prenatal infection animal models as well as schizophrenia.
PMCID: PMC3547943  PMID: 23349891
8.  Neonatal Behavioral Changes in Rats With Gestational Exposure to Lipopolysaccharide: A Prenatal Infection Model for Developmental Neuropsychiatric Disorders 
Schizophrenia Bulletin  2010;38(3):444-456.
Exposure to prenatal infections has been widely associated with the increased risk for neuropsychiatric disorders of developmental origin such as schizophrenia and autism. Although several behavioral and cognitive deficits have been detected during adulthood in rodent models of prenatal infections, early behavioral changes have not been well characterized. In a prenatal lipopolysaccharide (LPS) model, we have previously observed significant alterations in the neuronal cytoarchitecture during early postnatal life. In the present study, we aimed to investigate the potential effects of prenatal immune activation on early neurophenotypic presentations using a set of behavioral test battery. Female Sprague-Dawley rats were administered with 100 μg/kg LPS (intraperitoneally) at gestational days 15 and 16. During the first postnatal week, we found no significant effect on maternal behavior or mother-pup interaction by this treatment. Also, no major changes in physical developmental milestones of pups were noted from postnatal (P) days P6 to P16. Importantly, prenatal LPS-exposed pups had a significant decrease in the number and duration of ultrasonic vocalization calls at P3 and P5. Prenatal LPS treatment also led to impairments in nest-seeking behavior and odor-stroke associative learning in neonatal rats at P8 and P9. At the molecular level, we detected significant decrease in the expression of cortical 5HT1A and 5HT1B messenger RNA at P3. These data suggest that prenatal exposure to an immune activator can significantly impair the social/communicative behavior in the neonate offspring, which may be relevant to childhood and premorbid abnormalities reported in autism and schizophrenia subjects.
PMCID: PMC3329978  PMID: 20805287
schizophrenia; immune activation; autism; serotonin; premorbid
9.  Nuclear Factor Erythroid 2-Related Factor 2 Facilitates Neuronal Glutathione Synthesis by Upregulating Neuronal Excitatory Amino Acid Transporter 3 Expression 
The Journal of Neuroscience  2011;31(20):7392-7401.
Astrocytes support neuronal antioxidant capacity by releasing glutathione, which is cleaved to cysteine in brain extracellular space. Free cysteine is then taken up by neurons through excitatory amino acid transporter 3 [EAAT3; also termed Slc1a1 (solute carrier family 1 member 1)] to support de novo glutathione synthesis. Activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant responsive element (ARE) pathway by oxidative stress promotes astrocyte release of glutathione, but it remains unknown how this release is coupled to neuronal glutathione synthesis. Here we evaluated transcriptional regulation of the neuronal cysteine transporter EAAT3 by the Nrf2-ARE pathway. Nrf2 activators and Nrf2 overexpression both produced EAAT3 transcriptional activation in C6 cells. A conserved ARE-related sequence was found in the EAAT3 promoter of several mammalian species. This ARE-related sequence was bound by Nrf2 in mouse neurons in vivo as observed by chromatin immunoprecipitation. Chemical activation of the Nrf2-ARE pathway in mouse brain increased both neuronal EAAT3 levels and neuronal glutathione content, and these effects were abrogated in mice genetically deficient in either Nrf2 or EAAT3. Selective overexpression of Nrf2 in brain neurons by lentiviral gene transfer was sufficient to upregulate both neuronal EAAT3 protein and glutathione content. These findings identify a mechanism whereby Nrf2 activation can coordinate astrocyte glutathione release with neuronal glutathione synthesis through transcriptional upregulation of neuronal EAAT3 expression.
PMCID: PMC3339848  PMID: 21593323
10.  A cleanroom sleeping environment’s impact on markers of oxidative stress, immune dysregulation, and behavior in children with autism spectrum disorders 
An emerging paradigm suggests children with autism display a unique pattern of environmental, genetic, and epigenetic triggers that make them susceptible to developing dysfunctional heavy metal and chemical detoxification systems. These abnormalities could be caused by alterations in the methylation, sulfation, and metalloprotein pathways. This study sought to evaluate the physiological and behavioral effects of children with autism sleeping in an International Organization for Standardization Class 5 cleanroom.
Ten children with autism, ages 3–12, slept in a cleanroom for two weeks to evaluate changes in toxin levels, oxidative stress, immune dysregulation, and behavior. Before and after the children slept in the cleanroom, samples of blood and hair and rating scale scores were obtained to assess these changes.
Five children significantly lowered their concentration of oxidized glutathione, a biomarker of oxidative stress. The younger cohort, age 5 and under, showed significantly greater mean decreases in two markers of immune dysregulation, CD3% and CD4%, than the older cohort. Changes in serum magnesium, influencing neuronal regulation, correlated negatively while changes in serum iron, affecting oxygenation of tissues, correlated positively with age. Changes in serum benzene and PCB 28 concentrations showed significant negative correlations with age. The younger children demonstrated significant improvements on behavioral rating scales compared to the older children. In a younger pair of identical twins, one twin showed significantly greater improvements in 4 out of 5 markers of oxidative stress, which corresponded with better overall behavioral rating scale scores than the other twin.
Younger children who slept in the cleanroom altered elemental levels, decreased immune dysregulation, and improved behavioral rating scales, suggesting that their detoxification metabolism was briefly enhanced. The older children displayed a worsening in behavioral rating scale performance, which may have been caused by the mobilization of toxins from their tissues. The interpretation of this exploratory study is limited by lack of a control group and small sample size. The changes in physiology and behavior noted suggest that performance of larger, prospective controlled studies of exposure to nighttime or 24 hour cleanroom conditions for longer time periods may be useful for understanding detoxification in children with autism.
Trial registration
Clinical Trial Registration Number NCT02195401 (Obtained July 18, 2014).
PMCID: PMC4374395  PMID: 25887094
Autism; Behavioral rating scales; Cleanroom; Glutathione; Immune dysregulation; Oxidative stress
11.  Elevated 5-hydroxymethylcytosine in the Engrailed-2 (EN-2) promoter is associated with increased gene expression and decreased MeCP2 binding in autism cerebellum 
Translational Psychiatry  2014;4(10):e460-.
Epigenetic mechanisms regulate programmed gene expression during prenatal neurogenesis and serve as a mediator between genetics and environment in postnatal life. The recent discovery of 5-hydroxymethylcytosine (5-hmC), with highest concentration in the brain, has added a new dimension to epigenetic regulation of neurogenesis and the development of complex behavior disorders. Here, we take a candidate gene approach to define the role 5-hmC in Engrailed-2 (EN-2) gene expression in the autism cerebellum. The EN-2 homeobox transcription factor, previously implicated in autism, is essential for normal cerebellar patterning and development. We previously reported EN-2 overexpression associated with promoter DNA hypermethylation in the autism cerebellum but because traditional DNA methylation methodology cannot distinguish 5-methylcytosine (5-mC) from 5-hmC, we now extend our investigation by quantifying global and gene-specific 5-mC and 5-hmC. Globally, 5-hmC was significantly increased in the autism cerebellum and accompanied by increases in the expression of de novo methyltransferases DNMT3A and DNMT3B, ten-eleven translocase genes TET1 and TET3, and in 8-oxo-deoxyguanosine (8-oxo-dG) content, a marker of oxidative DNA damage. Within the EN-2 promoter, there was a significant positive correlation between 5-hmC content and EN-2 gene expression. Based on reports of reduced MeCP2 affinity for 5-hmC, MeCP2 binding studies in the EN-2 promoter revealed a significant decrease in repressive MeCP2 binding that may contribute to the aberrant overexpression of EN-2. Because normal cerebellar development depends on perinatal EN-2 downregulation, the sustained postnatal overexpression suggests that a critical window of cerebellar development may have been missed in some individuals with autism with downstream developmental consequences. Epigenetic regulation of the programmed on-off switches in gene expression that occur at birth and during early brain development warrants further investigation
PMCID: PMC4350522  PMID: 25290267
12.  Associations of hypomelanotic skin disorders with autism: Do they reflect the effects of genetic mutations and epigenetic factors on vitamin-D metabolism in individuals at risk for autism? 
Vitamin D is crucial for full functioning in many genes, and vitamin-D deficiency interferes with many processes, including brain development and DNA repair. Several lines of evidence suggest that prenatal and early postnatal vitamin-D deficiency increases risk for autism, probably through multiple effects that include impaired brain development and increased de novo mutations. High rates of autism in several genetically based hypomelanotic skin disorders present a puzzle, because ultraviolet-B (UVB) radiation acting on skin is the major natural source of vitamin D, and lighter skin, which increases UVB penetration, helps protect against vitamin-D deficiency, especially at higher latitudes. Understanding autism’s association with hypomelanosis may elucidate autism’s etiology.
We consider two hypotheses that may help explain autism’s association with hypomelanotic disorders. Hypothesis 1) Because genetic and epigenetic variants that produce hypomelanotic conditions may help protect against vitamin-D deficiency, especially at higher latitudes, these variants may tend to decrease mortality – and increase the fertility – of individuals who also carry genetic or epigenetic factors that increase vulnerability to autism. Hypothesis 2) Children with hypomelanotic conditions will be more likely to develop autism, because children’s photosensitivity and parental concerns about sunburn and skin cancer lead them to excessively reduce children’s sun exposure and resultant vitamin-D levels.
One approach to testing these hypotheses would involve comparing the genomes, epigenetic markers, skin pigmentation, and serum and brain levels of the active form of vitamin D in autistic individuals, with and without co-morbid hypomelanoses, as well as in their relatives and controls. Because availability of UVB radiation varies widely around the world, epidemiological and genetic studies of the co-morbidity in different regions would provide complementary means of testing the hypotheses.
If test results support either hypothesis, they will add important evidence for an etiologic role of vitamin-D deficiency in autism, as well as supporting investigation of whether vitamin-D enhancement may aid treatment and prevention of autism.
PMCID: PMC4109325  PMID: 25067901
13.  Prenatal methylmercury exposure hampers glutathione antioxidant system ontogenesis and causes long-lasting oxidative stress in the mouse brain 
Toxicology and applied pharmacology  2007;227(1):147-154.
During the perinatal period, the central nervous system (CNS) is extremely sensitive to metals, including methylmercury (MeHg). Although the mechanism(s) associated with MeHg-induced developmental neurotoxicity remains obscure, several studies point to the glutathione (GSH) antioxidant system as an important molecular target for this toxicant. To extend our recent findings of MeHg-induced GSH dyshomeostasis, the present study was designed to assess the developmental profile of the GSH antioxidant system in the mouse brain during the early postnatal period after in utero exposure to MeHg. Pregnant mice were exposed to different doses of MeHg (1, 3 and 10 mg/L, diluted in drinking water, ad libitum) during the gestational period. After delivery, pups were killed at different time points - postnatal days (PNDs) 1, 11 and 21 - and the whole brain was used for determining biochemical parameters related to the antioxidant GSH system, as well as mercury content and the levels of F2-isoprostane. In control animals, cerebral GSH levels significantly increased over time during the early postnatal period; gestational exposure to MeHg caused a dose-dependent inhibition of this developmental event. Cerebral glutathione peroxidase (GPx) and glutathione reductase (GR) activities significantly increased over time during the early postnatal period in control animals; gestational MeHg exposure induced a dose-dependent inhibitory effect on both developmental phenomena. These adverse effects of prenatal MeHg exposure were corroborated by marked increases in cerebral F2-isoprostanes levels at all time points. Significant negative correlations were found between F2-isoprostanes and GSH, as well as between F2-isoprostanes and GPx activity, suggesting that MeHg-induced disruption of the GSH system maturation is related to MeHg-induced increased lipid peroxidation in the pup brain. In utero MeHg exposure also caused a dose-dependent increase in the cerebral levels of mercury at birth. Even though the cerebral mercury concentration decreased to nearly basal levels at postnatal day 21, GSH levels, GPx and GR activities remained decreased in MeHg-exposed mice, indicating that prenatal exposure to MeHg affects the cerebral GSH antioxidant systems by inducing biochemical alterations that endure even when mercury tissue levels decrease and become indistinguishable from those noted in pups born to control dams. This study is the first to show that prenatal exposure to MeHg disrupts the postnatal development of the glutathione antioxidant system in the mouse brain, pointing to an additional molecular mechanism by which MeHg induces pro-oxidative damage in the developing CNS. Moreover, our experimental observation corroborates previous reports on the permanent functional deficits observed after prenatal MeHg exposure.
PMCID: PMC2955629  PMID: 18023834
Methylmercury; prenatal exposure; developmental neurotoxicity; glutathione; oxidative stress; antioxidant enzymes
14.  Reduced Serotonin Receptor Subtypes in a Limbic and a Neocortical Region in Autism 
Autism is a behaviorally defined, neurological disorder with symptom onset before the age of three. Abnormalities in social-emotional behaviors are a core deficit in autism and are characterized by impaired reciprocal social interaction, lack of facial expressions, and the inability to recognize familiar faces. The posterior cingulate cortex (PCC) and fusiform gyrus (FG) are two regions within an extensive limbic-cortical network that contribute to social-emotional behaviors. Evidence indicates that changes in brains of individuals with autism begin prenatally. Serotonin (5HT) is one of the earliest expressed neurotransmitters, and plays an important role in synaptogenesis, neurite outgrowth, and neuronal migration. Abnormalities in 5HT systems have been implicated in several psychiatric disorders including autism, as evidenced by immunology, imaging, genetics, pharmacotherapy, and neuropathology. Although information is known regarding peripheral 5HT in autism, there is emerging evidence that 5HT systems in the CNS, including various 5HT receptor subtypes and transporters, are affected in autism. The present study demonstrated significant reductions in 5HT1A receptor binding density in superficial and deep layers of the PCC and FG, and in the density of 5HT2A receptors in superficial layers of the PCC and FG. Significant reduction in the density of serotonin transporters (5-HTT) was also found in the deep layers of the FG, but normal levels were demonstrated in both layers of the PCC and superficial layers of the FG. These studies provide potential substrates for decreased 5-HT modulation/innervation in the autism brain, and implicate two 5-HT receptor subtypes as potential neuromarkers for novel or existing pharmacotherapies.
PMCID: PMC3859849  PMID: 23894004
Autism; Serotonin; 5-HT1A receptors; 5-HT2A receptors; 5-HT transporters; pharmacotherapy; Selective Serotonin Re-uptake Inhibitors (SSRIs)
15.  Dietary Intake and Plasma Levels of Choline and Betaine in Children with Autism Spectrum Disorders 
Autism Research and Treatment  2013;2013:578429.
Abnormalities in folate-dependent one-carbon metabolism have been reported in many children with autism. Because inadequate choline and betaine can negatively affect folate metabolism and in turn downstream methylation and antioxidant capacity, we sought to determine whether dietary intake of choline and betaine in children with autism was adequate to meet nutritional needs based on national recommendations. Three-day food records were analyzed for 288 children with autism (ASDs) who participated in the national Autism Intervention Research Network for Physical Health (AIR-P) Study on Diet and Nutrition in children with autism. Plasma concentrations of choline and betaine were measured in a subgroup of 35 children with ASDs and 32 age-matched control children. The results indicated that 60–93% of children with ASDs were consuming less than the recommended Adequate Intake (AI) for choline. Strong positive correlations were found between dietary intake and plasma concentrations of choline and betaine in autistic children as well as lower plasma concentrations compared to the control group. We conclude that choline and betaine intake is inadequate in a significant subgroup of children with ASDs and is reflected in lower plasma levels. Inadequate intake of choline and betaine may contribute to the metabolic abnormalities observed in many children with autism and warrants attention in nutritional counseling.
PMCID: PMC3876775  PMID: 24396597
16.  A Glutathione-Nrf2-Thioredoxin Cross-Talk Ensures Keratinocyte Survival and Efficient Wound Repair 
PLoS Genetics  2016;12(1):e1005800.
The tripeptide glutathione is the most abundant cellular antioxidant with high medical relevance, and it is also required as a co-factor for various enzymes involved in the detoxification of reactive oxygen species and toxic compounds. However, its cell-type specific functions and its interaction with other cytoprotective molecules are largely unknown. Using a combination of mouse genetics, functional cell biology and pharmacology, we unraveled the function of glutathione in keratinocytes and its cross-talk with other antioxidant defense systems. Mice with keratinocyte-specific deficiency in glutamate cysteine ligase, which catalyzes the rate-limiting step in glutathione biosynthesis, showed a strong reduction in keratinocyte viability in vitro and in the skin in vivo. The cells died predominantly by apoptosis, but also showed features of ferroptosis and necroptosis. The increased cell death was associated with increased levels of reactive oxygen and nitrogen species, which caused DNA and mitochondrial damage. However, epidermal architecture, and even healing of excisional skin wounds were only mildly affected in the mutant mice. The cytoprotective transcription factor Nrf2 was strongly activated in glutathione-deficient keratinocytes, but additional loss of Nrf2 did not aggravate the phenotype, demonstrating that the cytoprotective effect of Nrf2 is glutathione dependent. However, we show that deficiency in glutathione biosynthesis is efficiently compensated in keratinocytes by the cysteine/cystine and thioredoxin systems. Therefore, our study highlights a remarkable antioxidant capacity of the epidermis that ensures skin integrity and efficient wound healing.
Author Summary
The skin is frequently exposed to various challenges that cause oxidative stress, such as UV irradiation, exposure to toxic chemicals or mechanical injury. Therefore, keratinocytes -the major cell type of the outermost layer of our skin—need sophisticated antioxidant defense systems. However, the relevance of individual defense systems and their interaction in the cell are largely unknown. Here we studied the role of glutathione, the most abundant cellular antioxidant, in keratinocytes. We show that in the absence of the enzyme that catalyzes the rate-limiting step in glutathione biosynthesis, keratinocytes initiate a complex cell death program, resulting in reduced survival of these cells in culture and in mouse skin. Despite this, the epidermal structure was only mildly affected and the mutant mice were even able to heal full-thickness excisional skin wounds. We found that this is ensured by compensatory functions of another antioxidant defense system, allowing survival of keratinocytes in the absence of glutathione. These results therefore demonstrate a remarkable antioxidant defense capacity of keratinocytes that guarantees maintenance of the essential barrier of the skin and efficient wound repair.
PMCID: PMC4726503  PMID: 26808544
17.  Animal Models of Autism: An Epigenetic and Environmental Viewpoint 
Autism is a neurodevelopmental disorder of social behavior, which is more common in males than in females. The causes of autism are unknown; there is evidence for a substantial genetic component, but it is likely that a combination of genetic, environmental and epigenetic factors contribute to its complex pathogenesis. Rodent models that mimic the behavioral deficits of autism can be useful tools for dissecting both the etiology and molecular mechanisms. This review discusses animal models of autism generated by prenatal or neonatal environmental challenges, including virus infection and exposure to valproic acid (VPA) or stress. Studies of viral infection models suggest that interleukin-6 can influence fetal development and programming. Prenatal exposure to the histone deacetylase inhibitor VPA has been linked to autism in children, and male VPA-exposed rats exhibit a spectrum of autistic-like behaviors. The experience of prenatal stress produces male-specific behavioral abnormalities in rats. These effects may be mediated by epigenetic modifications such as DNA methylation and histone acetylation resulting in alterations to the transcriptome.
PMCID: PMC3661233  PMID: 23861630
autism; environmental factors; epigenetic processes; experimental animal models
18.  Aberrant Rab11-Dependent Trafficking of the Neuronal Glutamate Transporter EAAC1 Causes Oxidative Stress and Cell Death in Huntington's Disease 
The Journal of Neuroscience  2010;30(13):4552-4561.
Oxidative stress contributes to neurodegeneration in Huntington's disease (HD). However, the origins of oxidative stress in HD remain unclear. Studies in HD transgenic models suggest involvement of mitochondrial dysfunction, which would lead to overproduction of reactive oxygen species (ROS). Impaired mitochondria complexes occur in late stages of HD but not in presymptomatic or early-stage HD patients. Thus, other mechanisms may account for the earliest source of oxidative stress caused by endogenous mutant huntingtin. Here, we report that decreased levels of a major intracellular antioxidant glutathione coincide with accumulation of ROS in primary HD neurons prepared from embryos of HD knock-in mice (HD140Q/140Q), which have human huntingtin exon 1 with 140 CAG repeats inserted into the endogenous mouse huntingtin gene. Uptake of extracellular cysteine through the glutamate/cysteine transporter EAAC1 is required for de novo synthesis of glutathione in neurons. We found that, compared with wild-type neurons, HD neurons had lower cell surface levels of EAAC1 and were deficient in taking up cysteine. Constitutive trafficking of EAAC1 from recycling endosomes relies on Rab11 activity, which is defective in the brain of HD140Q/140Q mice. Enhancement of Rab11 activity by expression of a dominant-active Rab11 mutant in primary HD neurons ameliorated the deficit in cysteine uptake, increased levels of intracellular glutathione, normalized clearance of ROS, and improved neuronal survival. Our data support a novel mechanism for oxidative stress in HD: Rab11 dysfunction slows trafficking of EAAC1 to the cell surface and impairs cysteine uptake, thereby leading to deficient synthesis of glutathione.
PMCID: PMC3842456  PMID: 20357106
19.  Neuregulin 1 Promotes Glutathione-Dependent Neuronal Cobalamin Metabolism by Stimulating Cysteine Uptake 
Neuregulin 1 (NRG-1) is a key neurotrophic factor involved in energy homeostasis and CNS development, and impaired NRG-1 signaling is associated with neurological disorders. Cobalamin (Cbl), also known as vitamin B12, is an essential micronutrient which mammals must acquire through diet, and neurologic dysfunction is a primary clinical manifestation of Cbl deficiency. Here we show that NRG-1 stimulates synthesis of the two bioactive Cbl species adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) in human neuroblastoma cells by both promoting conversion of inactive to active Cbl species and increasing neuronal Cbl uptake. Formation of active Cbls is glutathione- (GSH-) dependent and the NRG-1-initiated increase is dependent upon its stimulation of cysteine uptake by excitatory amino acid transporter 3 (EAAT3), leading to increased GSH. The stimulatory effect of NRG-1 on cellular Cbl uptake is associated with increased expression of megalin, which is known to facilitate Cbl transport in ileum and kidney. MeCbl is a required cofactor for methionine synthase (MS) and we demonstrate the ability of NRG-1 to increase MS activity, and affect levels of methionine methylation cycle metabolites. Our results identify novel neuroprotective roles of NRG-1 including stimulating antioxidant synthesis and promoting active Cbl formation.
PMCID: PMC4709767  PMID: 27057274
20.  Metabolic Imbalance Associated with Methylation Dysregulation and Oxidative Damage in Children with Autism 
Oxidative stress and abnormal DNA methylation have been implicated in the pathophysiology of autism. We investigated the dynamics of an integrated metabolic pathway essential for cellular antioxidant and methylation capacity in 68 children with autism, 54 age-matched control children and 40 unaffected siblings. The metabolic profile of unaffected siblings differed significantly from case siblings but not from controls. Oxidative protein/DNA damage and DNA hypomethylation (epigenetic alteration) were found in autistic children but not paired siblings or controls. These data indicate that the deficit in antioxidant and methylation capacity is specific for autism and may promote cellular damage and altered epigenetic gene expression. Further, these results suggest a plausible mechanism by which pro-oxidant environmental stressors may modulate genetic predisposition to autism.
PMCID: PMC3342663  PMID: 21519954
Autism; Oxidative stress; Metabolic; Epigenetics; Glutathione; DNA methylation
21.  Epigenetics and Neural Developmental Disorders: Washington DC, September 18 and 19, 2006 
Neural developmental disorders, such as autism, Rett Syndrome, Fragile X syndrome, and Angelman syndrome manifest during early postnatal neural development. Although the genes responsible for some of these disorders have been identified, how the mutations of these genes affect neural development is currently unclear. Emerging evidence suggest that these disorders share common underlying defects in neuronal morphology, synaptic connectivity and brain plasticity. In particular, alterations in dendritic branching and spine morphology play a central role in the pathophysiology of most mental retardation disorders, suggesting that common pathways regulating neuronal function may be affected. Epigenetic modulations, mediated by DNA methylation, RNA-associated silencing, and histone modification, can serve as an intermediate process that imprints dynamic environmental experiences on the “fixed” genome, resulting in stable alterations in phenotypes. Disturbance in epigenetic regulations can lead to inappropriate expression or silencing of genes, causing an array of multi-system disorders and neoplasias. Rett syndrome, the most common form of mental retardation in young girls, is due to l mutation of MECP2, encoding a methylated DNA binding protein that translates DNA methylation into gene repression. Angelman syndrome is due to faulty genomic imprinting or maternal mutations in UBE3A. Fragile X Syndrome, in most cases, results from the hypermethylation of FMR1 promoter, hence the loss of expression of functional FMRP protein. Autism, with its complex etiology, may have strong epigenetic link. Together, these observations strongly suggest that epigenetic mechanisms may play a critical role in brain development and etiology of related disorders. This report summarizes the scientific discussions and major conclusions from a recent conference that aimed to gain insight into the common molecular pathways affected among these disorders and discover potential therapeutic targets that have been missed by looking at one disorder at a time.
PMCID: PMC2700626  PMID: 17965627
Epigenetic; DNA methylation; chromatin; development; Rett Syndrome; Fragile X syndrome; Angelman syndrome; autism; neuronal maturation; synaptogenesis
22.  Altered posterior cingulate cortical cyctoarchitecture, but normal density of neurons and interneurons in the posterior cingulate cortex and fusiform gyrus in autism 
Lay Abstract
Autism is a behaviorally defined disorder with increasing prevalence rates globally. The disorder is characterized by deficits in several domains including social behaviors, restricted and repetitive behaviors, and deficits in communication. Two regions thought to contribute to deficits in social behavior are the posterior cingulate cortex (PCC) and fusiform gyrus (FFG). The PCC is involved in processing emotionally salient stimuli, and also has a role in processing faces. The FFG is the area responsible for object and face recognition. A potential imbalance between excitatory and inhibitory processing in the brain may contribute to some of the abnormal social behaviors observed in autism. This is supported by previous work suggesting reduced GABA receptors in the autistic brain. The present study used thionin stained section to qualitatively assess cortical patterning and quantitatively assess the density of neurons. Furthermore, immunohistochemistry was used to determine the density of a subset of GABAergic interneurons. In the autistic brain, the PCC displayed several abnormal cortical patterns including irregularly distributed neurons in specific cortical layers, and the presence of increased white matter neurons. In marked contrast, the FFG appeared normal and there were no significant differences in the density of neurons or interneurons in either region. The present study highlights the presence of abnormal findings in the PCC, which appear to have developmental origins and could affect local processing of social-emotional behaviors as well as the function of interrelated cortical areas.
Scientific Abstract
Autism is a developmental disorder with prenatal origins, currently estimated to affect 1 in 91 children in the United States. Social-emotional deficits are a hallmark of autism and early neuropathology studies have indicated involvement of the limbic system. Imaging studies demonstrate abnormal activation of the posterior cingulate cortex (PCC), a component of the limbic system. Abnormal activation has also been noted in the fusiform gyrus (FFG), a region important for facial recognition and a key element in social interaction. A potential imbalance between excitatory and inhibitory interneurons in the cortex may contribute to altered information processing in autism. Furthermore, reduced numbers of GABA receptors have previously been reported in the autistic brain. Thionin stained sections were used to qualitatively assess cytoarchitectonic patterning and quantitatively determine the density of neurons and immunohistochemistry was used to determine the densities of a subset of GABAergic interneurons utilizing parvalbumin- and calbindin- immunoreactivity. In autism, the PCC displayed altered cytoarchitecture with irregularly distributed neurons, poorly demarcated layers IV and V, and increased presence of white matter neurons. In contrast, no neuropathology was observed in the FFG. There was no significant difference in the density of thionin, parvalbumin, or calbindin interneurons in either region and there was a trend towards a reduced density of calbindin neurons in the PCC. This study highlights the presence of abnormal findings in the PCC, which appear to be developmental in nature and could affect the local processing of social-emotional behaviors as well as functioning of interrelated areas.
PMCID: PMC3110607  PMID: 21360830
23.  Age-Dependent Brain Gene Expression and Copy Number Anomalies in Autism Suggest Distinct Pathological Processes at Young Versus Mature Ages 
PLoS Genetics  2012;8(3):e1002592.
Autism is a highly heritable neurodevelopmental disorder, yet the genetic underpinnings of the disorder are largely unknown. Aberrant brain overgrowth is a well-replicated observation in the autism literature; but association, linkage, and expression studies have not identified genetic factors that explain this trajectory. Few studies have had sufficient statistical power to investigate whole-genome gene expression and genotypic variation in the autistic brain, especially in regions that display the greatest growth abnormality. Previous functional genomic studies have identified possible alterations in transcript levels of genes related to neurodevelopment and immune function. Thus, there is a need for genetic studies involving key brain regions to replicate these findings and solidify the role of particular functional pathways in autism pathogenesis. We therefore sought to identify abnormal brain gene expression patterns via whole-genome analysis of mRNA levels and copy number variations (CNVs) in autistic and control postmortem brain samples. We focused on prefrontal cortex tissue where excess neuron numbers and cortical overgrowth are pronounced in the majority of autism cases. We found evidence for dysregulation in pathways governing cell number, cortical patterning, and differentiation in young autistic prefrontal cortex. In contrast, adult autistic prefrontal cortex showed dysregulation of signaling and repair pathways. Genes regulating cell cycle also exhibited autism-specific CNVs in DNA derived from prefrontal cortex, and these genes were significantly associated with autism in genome-wide association study datasets. Our results suggest that CNVs and age-dependent gene expression changes in autism may reflect distinct pathological processes in the developing versus the mature autistic prefrontal cortex. Our results raise the hypothesis that genetic dysregulation in the developing brain leads to abnormal regional patterning, excess prefrontal neurons, cortical overgrowth, and neural dysfunction in autism.
Author Summary
Autism is a disorder characterized by aberrant social, communication, and restricted and repetitive behaviors. It develops clinically in the first years of life. Toddlers and children with autism often exhibit early brain enlargement and excess neuron numbers in the prefrontal cortex. Adults with autism generally do not display enlargement but instead may have a smaller brain size. Thus, we investigated DNA and mRNA patterns in prefrontal cortex from young versus adult postmortem individuals with autism to identify age-related gene expression differences as well as possible genetic correlates of abnormal brain enlargement, excess neuron numbers, and abnormal functioning in this disorder. We found abnormalities in genetic pathways governing cell number, neurodevelopment, and cortical lateralization in autism. We also found that the key pathways associated with autism are different between younger and older autistic individuals. These findings suggest that dysregulated gene pathways in the early stages of neurodevelopment could lead to later behavioral and cognitive deficits associated with autism.
PMCID: PMC3310790  PMID: 22457638
24.  Prenatal Treatment for Serious Neurological Sequelae of Congenital Toxoplasmosis: An Observational Prospective Cohort Study 
PLoS Medicine  2010;7(10):e1000351.
An observational study by Ruth Gilbert and colleagues finds that prenatal treatment of congenital toxoplasmosis could substantially reduce the proportion of infected fetuses that develop serious neurological sequelae.
The effectiveness of prenatal treatment to prevent serious neurological sequelae (SNSD) of congenital toxoplasmosis is not known.
Methods and Findings
Congenital toxoplasmosis was prospectively identified by universal prenatal or neonatal screening in 14 European centres and children were followed for a median of 4 years. We evaluated determinants of postnatal death or SNSD defined by one or more of functional neurological abnormalities, severe bilateral visual impairment, or pregnancy termination for confirmed congenital toxoplasmosis. Two-thirds of the cohort received prenatal treatment (189/293; 65%). 23/293 (8%) fetuses developed SNSD of which nine were pregnancy terminations. Prenatal treatment reduced the risk of SNSD. The odds ratio for prenatal treatment, adjusted for gestational age at maternal seroconversion, was 0.24 (95% Bayesian credible intervals 0.07–0.71). This effect was robust to most sensitivity analyses. The number of infected fetuses needed to be treated to prevent one case of SNSD was three (95% Bayesian credible intervals 2–15) after maternal seroconversion at 10 weeks, and 18 (9–75) at 30 weeks of gestation. Pyrimethamine-sulphonamide treatment did not reduce SNSD compared with spiramycin alone (adjusted odds ratio 0.78, 0.21–2.95). The proportion of live-born infants with intracranial lesions detected postnatally who developed SNSD was 31.0% (17.0%–38.1%).
The finding that prenatal treatment reduced the risk of SNSD in infected fetuses should be interpreted with caution because of the low number of SNSD cases and uncertainty about the timing of maternal seroconversion. As these are observational data, policy decisions about screening require further evidence from a randomized trial of prenatal screening and from cost-effectiveness analyses that take into account the incidence and prevalence of maternal infection.
Please see later in the article for the Editors' Summary
Editors' Summary
Toxoplasmosis is a very common parasitic infection. People usually become infected with Toxoplasma gondii, the parasite that causes toxoplasmosis, by eating raw or undercooked meat that contains the parasite, but it can also be contracted by drinking unfiltered water or by handling cat litter. Most people with toxoplasmosis never know they have the disease. However, if a pregnant woman becomes infected with T. gondii, she can transmit the parasite to her unborn baby (fetus). Overall, about a quarter of women who catch toxoplasmosis during pregnancy transmit the parasite to their fetus. If transmission occurs early during pregnancy, the resultant “congenital toxoplasmosis” increases the risk of miscarriage and the risk of the baby being born with brain damage, epilepsy, deafness, blindness, or developmental problems (“serious neurological sequelae”). In the worst cases, babies may be born dead or die soon after birth. Congenital toxoplasmosis caught during the final third of pregnancy may not initially cause any health problems but eyesight problems often develop later in life.
Why Was This Study Done?
Clinicians can find out if a woman has been infected with T. gondii during pregnancy by looking for parasite-specific antibodies (proteins made by the immune system that fight infections) in her blood. If the pattern of antibodies suggests a recent infection, the woman can be given spiramycin or pyrimethamine-sulfonamide, antibiotics that are thought to reduce the risk of transmission to the fetus and the severity of toxoplasmosis in infected fetuses. In some countries where toxoplasmosis is particularly common (for example, France), pregnant women are routinely screened for toxoplasmosis and treated with antibiotics if there are signs of recent infection. But is prenatal treatment an effective way to prevent the serious neurological sequelae or postnatal death (SNSD) associated with congenital toxoplasmosis? In this observational study, the researchers examine this question by studying a group of children identified as having congenital toxoplasmosis by prenatal or neonatal screening in six European countries. An observational study measures outcomes in a group of patients without trying to influence those outcomes by providing a specific treatment.
What Did the Researchers Do and Find?
The researchers followed 293 children in whom congenital toxoplasmosis had been identified by prenatal screening (in France, Austria, and Italy) or by neonatal screening (in Denmark, Sweden, and Poland) for an average 4 years. Two-thirds of the children received prenatal treatment for toxoplasmosis and 23 fetuses (8% of the fetuses) developed SNSD; nine of these cases of SNSD were terminated during pregnancy. By comparing the number of cases of SNSD among children who received prenatal treatment with the number among children who did not receive prenatal treatment, the researchers estimate that prenatal treatment reduced the risk of SNSD by three-quarters. They also estimate that to prevent one case of SNSD after maternal infection at 10 weeks of pregnancy, it would be necessary to treat three fetuses with confirmed infection. To prevent one case of SNSD after maternal infection at 30 weeks of pregnancy, 18 fetuses would need to be treated. Finally, the researchers report that the effectiveness of pyrimethamine-sulfonamide and spiramycin (which is less toxic) was similar, and that a third of live-born infants with brain damage that was detected after birth subsequently developed SNSD.
What Do These Findings Mean?
These findings suggest that prenatal treatment of congenital toxoplasmosis could substantially reduce the proportion of infected fetuses that develop SNDS and would be particularly effective in fetuses whose mothers acquired T. gondii during the first third of pregnancy. These findings should be interpreted with caution, however, because of the small number of affected fetuses in the study and because of uncertainty about the timing of maternal infection. Furthermore, these findings only relate to the relatively benign strain of T. gondii that predominates in Europe and North America; further studies are needed to test whether prenatal treatment is effective against the more virulent strains of the parasite that occur in South America. Finally, because this study is an observational study, its findings might reflect differences between the study participants other than whether or not they received prenatal treatment. These findings need to be confirmed in randomized controlled trials of prenatal screening, therefore, before any policy decisions are made about routine prenatal screening and treatment for congenital toxoplasmosis.
Additional Information
Please access these Web sites via the online version of this summary at
The US Centers for Disease Control and Prevention provides detailed information about all aspects of toxoplasmosis, including toxoplasmosis in pregnant women (in English and Spanish)
The UK National Health Services Choices website has information for patients about toxoplasmosis and about the risks of toxoplasmosis during pregnancy
KidsHealth, a resource maintained by the Nemours Foundation (a not-for-profit organization for children's health), provides information for parents about toxoplasmosis (in English and Spanish)
Tommy's, a nonprofit organization that funds research on the health of babies, also has information on toxoplasmosis
MedlinePlus provides links to other information on toxoplasmosis (in English and Spanish)
EUROTOXO contains reports generated by a European consensus development project
Uptodate provides information about toxoplasmosis and pregnancy
PMCID: PMC2953528  PMID: 20967235
25.  Supplementation of Korean Red Ginseng improves behavior deviations in animal models of autism 
Food & Nutrition Research  2016;60:10.3402/fnr.v60.29245.
Autism spectrum disorder (ASD) is heterogeneous neurodevelopmental disorders that primarily display social and communication impairments and restricted/repetitive behaviors. ASD prevalence has increased in recent years, yet very limited therapeutic targets and treatments are available to counteract the incapacitating disorder. Korean Red Ginseng (KRG) is a popular herbal plant in South Korea known for its wide range of therapeutic effects and nutritional benefits and has recently been gaining great scientific attention, particularly for its positive effects in the central nervous system.
Thus, in this study, we investigated the therapeutic potential of KRG in alleviating the neurobehavioral deficits found in the valproic acid (VPA)-exposed mice models of ASD.
Starting at 21 days old (P21), VPA-exposed mice were given daily oral administrations of KRG solution (100 or 200 mg/kg) until the termination of all experiments. From P28, mice behaviors were assessed in terms of social interaction capacity (P28–29), locomotor activity (P30), repetitive behaviors (P32), short-term spatial working memory (P34), motor coordination (P36), and seizure susceptibility (P38).
VPA-exposed mice showed sociability and social novelty preference deficits, hyperactivity, increased repetitive behavior, impaired spatial working memory, slightly affected motor coordination, and high seizure susceptibility. Remarkably, long-term KRG treatment in both dosages normalized all the ASD-related behaviors in VPA-exposed mice, except motor coordination ability.
As a food and herbal supplement with various known benefits, KRG demonstrated its therapeutic potential in rescuing abnormal behaviors related to autism caused by prenatal environmental exposure to VPA.
PMCID: PMC4737717  PMID: 26837496
Panax ginseng; nutraceutical; autistic behaviors; Korean Red Ginseng; prenatal VPA exposure

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