Proposal of auxiliary diagnosis index for autism spectrum disorder using near-infrared spectroscopy.

Lack of a diagnostic index is a problem that needs to be overcome in the diagnosis of autism spectrum disorder (ASD), because this problem prevents an objective assessment based on biomarkers. This paper describes the development of a diagnostic index for ASD using near-infrared spectroscopy (NIRS). We investigated continuous prefrontal hemodynamic changes depending on reciprocal disposition of working memory and nonworking memory tasks using two-channel NIRS. NIRS signals in the prefrontal cortex were compared between high-functioning ASD subjects ([Formula: see text]) and typically developed (TD) subjects ([Formula: see text]). The brain activities of the TD subjects were related to experimental design. These results were not confirmed in brain activities of ASD subjects, although the task performance rate was almost equivalent. The brain activities of TD subjects and ASD subjects were evaluated using a weighted separability (WS) index obtained from the feature phase of oxy-hemoglobin and its differential value. Calculation of the [Formula: see text]-test (TD subject versus ASD subject) confirmed that WS was significant. This result showed that the proposed index was useful for evaluation of the brain activity of ASD subjects.

Maternal viral infection during pregnancy impairs development of fetal serotonergic neurons.

BACKGROUND: Maternal viral infection during pregnancy induces morphological abnormalities in the fetus and may cause emotional and psychological problems in offspring through unknown mechanisms. We have previously shown that prenatal exposure of rats to chemicals such as thalidomide causes an autistic-like phenotype in offspring, indicating that prenatal events affecting serotonergic development may cause developmental disorder. METHODS: We investigated whether prenatal viral infection altered the expression of neurotransmitters involved in the emotional or psychological status of offspring. We here took advantage of the polyriboinosinic:polyribocytidylic acid (poly I:C) system, the synthetic double-stranded RNA, which is often used in animal models of viral infection. RESULTS: Ten mg/kg of poly I:C was intraperitoneally injected on gestational day (GD) 9 and counted the numbers of serotonin-immunopositive cells on GD15 using flat whole-mount preparation method, resulting 11.1% of increase in the number of serotonergic neurons in poly I:C group. Furthermore, there was a significant decrease in hippocampal serotonin content in offspring by postnatal day 50 following poly I:C administration by high-performance liquid chromatography. DISCUSSION AND CONCLUSION: Since serotonin is known to link with behavior and emotion after birth, these results suggest that maternal viral infection might cause, in addition to morphological abnormalities, serotonin-related pathogenesis such as neurodevelopmental disorders including autism spectrum disorders.

Localization of manserin, a secretogranin II-derived neuropeptide, in the oviduct of female rats.

Gynecological disorders related to menstrual cycle may be affected by stress and can cause infertility. Manserin is a stress-related neuropeptide that is present in the neuroendocrine system. In the present study, we determined the localization of manserin in the oviduct of adult Wistar rats using immunohistochemical techniques. Manserin was detected on the surface of the epithelium of the oviduct, but not in the ovary and uterus. Localization of manserin was specific to a large portion of the isthmus and to a small portion of the ampulla. These results suggest that manserin localizes to secretory cells in the oviduct and may be involved in stress-induced gynecological disorders.

Prenatal exposure to organomercury, thimerosal, persistently impairs the serotonergic and dopaminergic systems in the rat brain: implications for association with developmental disorders.

Thimerosal, an organomercury compound, has been widely used as a preservative. Therefore, concerns have been raised about its neurotoxicity. We recently demonstrated perturbation of early serotonergic development by prenatal exposure to thimerosal (Ida-Eto et al. (2011) [11]). Here, we investigated whether prenatal thimerosal exposure causes persistent impairment after birth. Analysis on postnatal day 50 showed significant increase in hippocampal serotonin following thimerosal administration on embryonic day 9. Furthermore, not only serotonin, striatal dopamine was significantly increased. These results indicate that embryonic exposure to thimerosal produces lasting impairment of brain monoaminergic system, and thus every effort should be made to avoid the use of thimerosal.

Subtype-specific parafollicular localization of the neuropeptide manserin in the rat thyroid gland.

The thyroid gland is an endocrine organ which is involved in metabolism, neuroexcitability, body growth and development. The thyroid gland is also involved in the regulation of calcium metabolism, which is not yet fully understood. In this study, we investigated the localization of the granin-derived neuropeptide, manserin, in the adult rat thyroid gland. Manserin immunoreactivity was detected in thyroid follicular epithelial cells. Intense manserin signals were also detected in some, but not all, parafollicular cells, indicating that parafollicular manserin may be subtype-specific. These results indicate that thyroid manserin may play pivotal roles in parafollicular cells and follicular epithelial cells such as in calcium metabolism and/or thyroid hormone secretion.

Existence of manserin, a secretogranin II-derived neuropeptide, in the rat inner ear: relevance to modulation of auditory and vestibular system.

Manserin is a 40-amino acid neuropeptide derived from rat brain. Manserin has been shown to distribute in the neuroendocrine system, such as the pituitary and adrenal glands, but it has been little studied in other organs. In this study, the authors examined localization of manserin in the inner ear of the adult Wistar rat using immunohistochemical analyses. Manserin immunoreactivity was detected in the neuronal terminals of the organ of Corti and type II spiral ganglion cells. In addition to being identified in the auditory system, manserin was detected at the synapses of the vestibular system, such as saccule, utricle, and semicircular canal. These results suggest that inner ear manserin may be involved in the function of peripheral auditory and vestibular systems.

Embryonic exposure to thimerosal, an organomercury compound, causes abnormal early development of serotonergic neurons.

Even though neuronal toxicity due to organomercury compounds is well known, thimerosal, an organomercury compound, is widely used in pediatric vaccine preservation. In the present study, we examined whether embryonic exposure to thimerosal affects early development of serotonergic neurons. Thimerosal (1mg Hg/kg) was intramuscularly administered to pregnant rats on gestational day 9 (susceptible time window for development of fetal serotonergic system), and fetal serotonergic neurons were assessed at embryonic day 15 using anti-serotonin antibodies. A dramatic increase in the number of serotonergic neurons localized to the lateral portion of the caudal raphe was observed in thimerosal group (1.9-fold increase, p<0.01 compared to control). These results indicate that embryonic exposure to thimerosal affects early development of serotonergic neurons.

Morphological abnormalities of embryonic cranial nerves after in utero exposure to valproic acid: implications for the pathogenesis of autism with multiple developmental anomalies.

Autism is often associated with multiple developmental anomalies including asymmetric facial palsy. In order to establish the etiology of autism with facial palsy, research into developmental abnormalities of the peripheral facial nerves is necessary. In the present study, to investigate the development of peripheral cranial nerves for use in an animal model of autism, rat embryos were treated with valproic acid (VPA) in utero and their cranial nerves were visualized by immunostaining. Treatment with VPA after embryonic day 9 had a significant effect on the peripheral fibers of several cranial nerves. Following VPA treatment, immunoreactivity within the trigeminal, facial, glossopharyngeal and vagus nerves was significantly reduced. Additionally, abnormal axonal pathways were observed in the peripheral facial nerves. Thus, the morphology of several cranial nerves, including the facial nerve, can be affected by prenatal VPA exposure as early as E13. Our findings indicate that disruption of early facial nerve development is involved in the etiology of asymmetric facial palsy, and may suggest a link to the etiology of autism.

Manserin, a secretogranin II-derived peptide, distributes in the rat endocrine pancreas colocalized with islet-cell specific manner.

Manserin is a recently characterized 40-amino acid neuropeptide derived from secretogranin II, a protein belonging to the chromogranin family. Although the physiological roles of manserin have not been elucidated to date, manserin has been shown to distribute in not only the brain but also the endocrine system such as the pituitary and adrenal glands, suggesting its role in the endocrine system. The present study aimed to explore the occurrence and distribution of manserin in the rat pancreas using an immunohistochemical technique with a polyclonal antibody against rat manserin. Immunoreactivity for manserin was readily detected in almost whole islets of Langerhans whereas not at all in the exocrine pancreas. Manserin-expressing cells were not colocalized with the glucagon-secreting cells (alpha cells), whereas they colocalized with insulin-secreting cells (beta cells) and somatostatin-secreting cells (delta cells), although their intracellular distribution was different. These results indicate that manserin, occurring in the endocrine pancreas, may have a potential role in the endocrine system.

Nonexploratory movement and behavioral alterations in a thalidomide or valproic acid-induced autism model rat.

Autism is a behaviorally characterized disorder with impairments in social interactions, as well as stereotyped, repetitive patterns of behaviors and interests. Exposure of rat fetuses to thalidomide (THAL) or valproic acid (VPA) on the ninth day of gestation has been reported as a useful model for human autism. We have shown that early serotonergic neural development is disrupted in these rats. In the current study, we used a radial maze and open field experimental paradigm to investigate whether these rats present behavioral and/or learning aberrations. THAL (500mg/kg), VPA (800mg/kg), or vehicle was administered orally to E9 pregnant rats at 7-10 weeks of age. Although the mean number of correct and incorrect arm choices in the initial eight arm choices did not differ between control and teratogen-exposed groups, achievement of learning (seven or eight consecutive correct choices for 3 consecutive days for individual rats) seemed to be impaired in teratogen-exposed groups. Interestingly, average time to explore the maze task was shorter in the teratogen-exposed groups, indicating that correct choice might be due to mere coincidence (i.e., nonexploratory movement). Unexpectedly, no significant differences were observed in social interaction in these rats. These results indicate that prenatal exposure to THAL and VPA might alter behavior in a manner that is, in part, consistent with human autism.

Recently identified a novel neuropeptide manserin colocalize with the TUNEL-positive cells in the top villi of the rat duodenum.

We recently isolated a novel 40 amino acid neuropeptide designated manserin from the rat brain. Manserin is derived from secretogranin II, a member of granin acidic secretory protein family by proteolytic processing, as previously reported secretoneurin and EM66. Manserin peptide are localized in the endocrine cells of the pituitary. In this study, we further investigated the manserin localization in the digestive system by immunohistochemical analysis using antimanserin antibody. In the duodenum, manserin immunostaining was exclusively observed in the nuclei of top villi instead of cytosol as observed in neurons in our previous study. Interestingly, manserin-positive cells in the duodenum are colocalized with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) positive cells, the cells whose DNA was damaged. Since the top villi of duodenum epithelial cells are known to undergo spontaneous apoptosis during epithelial cell turn over, and since other peptides such as secretoneurin and EM66 derived from SgII have been reported to be cancer-related, these results indicated that manserin peptide may have a role in apoptosis and/or cancer pathogenesis in the digestive organ.

[Genetic background of chronic fatigue syndrome].

Although previous twin and family studies have suggested the involvement of genetic factor(s) in the pathogenesis of chronic fatigue syndrome (CFS), responsible gene for CFS was not known. We have recently reported the association of serotonin transporter gene polymorphism in CFS. A significant increase of longer (L and XL) alleic variants was found in the CFS patients compared to the controls. Compared to S allele, the L allele is believed to retain higher transcriptional activity, which causes decreased concentration of serotonin in the extracellular space, namely, active serotonin in CFS. These results thus support the serotonin hypothesis in the pathogenesis of CFS.

Temporomandibular disorder is associated with a serotonin transporter gene polymorphism in the Japanese population.

AIMS: Recent genetic studies have linked serotonin-related genetic polymorphisms with diverse disorders characterized by functional somatic symptoms, including chronic fatigue syndrome, irritable bowel syndrome, and premenstrual dysphoric disorder. METHODS: We investigated three serotonin-related genetic polymorphisms by screening genomic DNA of 36 temporomandibular disorder (TMD) patients. RESULTS: A significant increase of longer alleles (l and xl) was found in the TMD patients compared to the controls both by the genotype-wise and the allele-wise analyses (both p < 0.01 by chi(2) test and Fisher's exact test). CONCLUSION: Genetic factors that involve the serotonergic system may play a role in the pathogenesis of TMD.

Hyperkalemia and hyperdopaminemia induced by an obsessive eating of banana in an anorexia nervosa adolescent.

Banana is known as a dopamine-rich and potassium-rich food, however no previous data regarding biochemical or psychological alteration induced by excess intake of banana has been reported. We have experienced an adolescent female case of Anorexia nervosa (AN) who denied eating anything but maximum 20 bananas and less than 500 ml mineral water per day for more than two years. During the period of massive banana eating habit, she showed increase of serum potassium (from 4.7 mEq/l to 6.1 mEq/l) and whole blood dopamine (from 11 ng/ml to 210 ng/ml; normal range 0.5-6.2 ng/ml), and obvious dysthymia that is inexplicable only by the pathology of AN. When the patient resumed other food ingestion after 26 months of obsessive and restricted eating of banana, the abnormalities in her blood data and her psychological state were all corrected toward normal. We conclude that in this case, the obsessive and restricted habit of banana ingestion resulted in hyperkalemia, hyperdopaminemia, and psychological change.

Modification of AMPA receptor properties following environmental enrichment.

Environmental enrichment results in many modifications in the brain such as structural, behavioural, and biochemical changes. alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type receptors for excitatory amino acid glutamate are recently found to be involved in neuronal plasticity. In this study, we examined whether environmental enrichment modified the brain expression of mRNA for subunit composition of AMPA receptors in adult mice using the real-time quantitative PCR method and western blotting. Mice housed in enriched environments showed significantly higher levels of GluR2 and GluR4 subunits in the hippocampus compared to control mice. We concluded that environmental enrichment can change the expression of AMPA receptor subunits and thus might modify the potentials of brain plasticity.

Maternal administration of thalidomide or valproic acid causes abnormal serotonergic neurons in the offspring: implication for pathogenesis of autism.

Embryonic exposure to thalidomide (THAL) or valproic acid (VPA) before neural tube closure has been demonstrated as a useful model for human autism in rats. Abnormalities of the serotonergic system which are often observed in human autism have been shown in these rats. Thus, we examined whether early serotonergic neuronal development is perturbed by THAL/VPA. When pregnant rats were exposed to THAL or VPA on embryonic day 9, a dramatic shift of the distribution of serotonergic neurons in the dorsal raphe nucleus was observed on postnatal day 50. This alteration is thought to reflect abnormality of serotonergic neuronal differentiation and migration. In vitro studies revealed that VPA retards the maturation of serotonergic neuron from ES cell-derived neuronal progenitors, whereas exogenously added Sonic hedgehog, a morphogen that has been implicated in serotonergic cell fate, partially prevented this retardation. These results indicate that disruption of early serotonergic neuronal development might be involved in the etiology of autism.

Manserin, a novel peptide from secretogranin II in the neuroendocrine system.

We have isolated a novel 40 amino acid neuropeptide, designated manserin, from the rat. Manserin is derived from secretogranin II (SgII), a member of granin acidic secretory protein family by proteolytic processing, as previously reported secretoneurin and EM66. Immunohistochemical analysis using anti-manserin antibody revealed that manserin localized in the endocrine cells of the pituitary anterior lobe, but not in the posterior lobe. Interestingly, manserin never co-localized with ACTH in the anterior pituitary, which is in contrast with SgII, suggesting specific immunoreactivity of the antiserum against manserin. Manserin immunostaining was also observed in the neuronal cells of several hypothalamic nuclei and the neurons in the median eminence. These results suggest that manserin exerts a specific role in the neuroendocrine system.

Serum neurotrophin concentrations in autism and mental retardation: a pilot study.

To evaluate the availability of the serum neurotrophins for the diagnosis of the patients with neurodevelopmental disorder, we measured the serum concentration of brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) in the patients diagnosed with autism (n=18) and mental retardation (n=20), or healthy controls (n=16), using enzyme-linked immunosorbent assay. There tended to be a higher concentration of serum BDNF found in the autistic group ( P <0.05 by analysis of variance (ANOVA)) and the mental retardation group ( P <0.001 by ANOVA) compared to the control group. Serum NT-4 concentration tended to be increased in the mental retardation group (P <0.05 by ANOVA). We conclude that measuring the serum concentration of two neurotrophins, BDNF and NT-4, might be helpful to diagnose or classify disorders such as autism or mental retardation.

Association between serotonin transporter gene polymorphism and chronic fatigue syndrome.

Interaction between the hypothalamo-pituitary-adrenal axis and the serotonergic system is thought to be disrupted in chronic fatigue syndrome (CFS) patients. We examined a serotonin transporter (5-HTT) gene promoter polymorphism, which affects the transcriptional efficiency of 5-HTT, in 78 CFS patients using PCR amplification of the blood genomic DNA. A significant increase of longer (L and XL) alleic variants was found in the CFS patients compared to the controls both by the genotype-wise and the allele-wise analyses (both p<0.05, by chi(2) test and Fisher's exact test). Attenuated concentration of extracellular serotonin due to longer variants may cause higher susceptibility to CFS.

[Anxiety in school refusal children with indefinite complaints: psychological estimation using State-Trait Anxiety Inventory and therapy by serotonin reuptake inhibitors].

Using State-Trait Anxiety Inventory (STAI) we examined 13 junior high school students with school refusal and indefinite complaints. Significant increase of the anxiety levels was higher in these children than in the control group. Serotonin reuptake inhibitors (SSRIs) were administered to 19 elementary and junior high school students with school refusal and indefinite complaints. The indefinite symptoms improved markedly in 2 children, moderately in 11, and mildly in 6. We conclude that high anxiety may cause indefinite symptoms in children with school refusal and that the treatment of indefinite symptoms with SSRI is an effective supportive therapy.