Updated View on the Relation of the Pineal Gland to Autism Spectrum Disorders

Significance of Melatonin in the Regulation of Circadian Rhythms and Disease Management

Melatonin, the 'hormone of darkness' is a neuronal hormone secreted by the pineal gland and other extra pineal sites. Responsible for the circadian rhythm and seasonal behaviour of vertebrates and mammals, melatonin is responsible for regulating various physiological conditions and the maintenance of sleep, body weight and the neuronal activities of the ocular sites. With its unique amphiphilic structure, melatonin can cross the cellular barriers and elucidate its activities in the subcellular components, including mitochondria. Melatonin is a potential scavenger of oxygen and nitrogen-reactive species and can directly obliterate the ROS and RNS by a receptor-independent mechanism. It can also regulate the pro- and anti-inflammatory cytokines in various pathological conditions and exhibit therapeutic activities against neurodegenerative, psychiatric disorders and cancer. Melatonin is also found to show its effects on major organs, particularly the brain, liver and heart, and also imparts a role in the modulation of the immune system. Thus, melatonin is a multifaceted candidate with immense therapeutic potential and is still considered an effective supplement on various therapies. This is primarily due to rectification of aberrant circadian rhythm by improvement of sleep quality associated with risk development of neurodegenerative, cognitive, cardiovascular and other metabolic disorders, thereby enhancing the quality of life.

The Bright Side of Psychedelics: Latest Advances and Challenges in Neuropharmacology

The need to identify effective therapies for the treatment of psychiatric disorders is a particularly important issue in modern societies. In addition, difficulties in finding new drugs have led pharmacologists to review and re-evaluate some past molecules, including psychedelics. For several years there has been growing interest among psychotherapists in psilocybin or lysergic acid diethylamide for the treatment of obsessive-compulsive disorder, of depression, or of post-traumatic stress disorder, although results are not always clear and definitive. In fact, the mechanisms of action of psychedelics are not yet fully understood and some molecular aspects have yet to be well defined. Thus, this review aims to summarize the ethnobotanical uses of the best-known psychedelic plants and the pharmacological mechanisms of the main active ingredients they contain. Furthermore, an up-to-date overview of structural and computational studies performed to evaluate the affinity and binding modes to biologically relevant receptors of ibogaine, mescaline, N,N-dimethyltryptamine, psilocin, and lysergic acid diethylamide is presented. Finally, the most recent clinical studies evaluating the efficacy of psychedelic molecules in some psychiatric disorders are discussed and compared with drugs already used in therapy.

Sulfur amino acid metabolism and related metabotypes of autism spectrum disorder: A review of biochemical evidence for a hypothesis

There are multiple lines of evidence for an impaired sulfur amino acid (SAA) metabolism in autism spectrum disorder (ASD). For instance, the concentrations of methionine, cysteine and S-adenosylmethionine (SAM) in body fluids of individuals with ASD is significantly lower while the concentration of S-adenosylhomocysteine (SAH) is significantly higher as compared to healthy individuals. Reduced methionine and SAM may reflect impaired remethylation pathway whereas increased SAH may reflect reduced S-adenosylhomocysteine hydrolase activity in the catabolic direction. Reduced SAM/SAH ratio reflects an impaired methylation capacity. We hypothesize multiple mechanisms to explain how the interplay of oxidative stress, neuroinflammation, mercury exposure, maternal use of valproate, altered gut microbiome and certain genetic variants may lead to these SAA metabotypes. Furthermore, we also propose a number of mechanisms to explain the metabolic consequences of abnormal SAA metabotypes. For instance in the brain, reduced SAM/SAH ratio will result in melatonin deficiency and hypomethylation of a number of biomolecules such as DNA, RNA and histones. In addition to previously proposed mechanisms, we propose that impaired activity of "radical SAM" enzymes will result in reduced endogenous lipoic acid synthesis, reduced molybdenum cofactor synthesis and impaired porphyrin metabolism leading to mitochondrial dysfunction, porphyrinuria and impaired sulfation capacity. Furthermore depletion of SAM may also lead to the disturbed mTOR signaling pathway in a subgroup of ASD. The proposed "SAM-depletion hypothesis" is an inclusive model to explain the relationship between heterogeneous risk factors and metabotypes observed in a subset of children with ASD.

Sleep and Sensory Processing in Infants and Toddlers: A Cross-Sectional and Longitudinal Study

IMPORTANCE

Typically developing children who are sensitive to sensory stimulation appear to have more sleep difficulties than children with average sensory sensitivities; however, at what age sleep difficulties emerge and whether they extend to children outside of sleep clinics are unclear.

OBJECTIVE

To investigate cross-sectional and longitudinal relationships between sleep and sensory processing in typically developing infants and toddlers.

DESIGN

Observational; cross-sectional and longitudinal.

SETTING

Community.

PARTICIPANTS

Children (N = 160) enrolled in a larger four-armed randomized controlled trial of overweight prevention in infancy (40 randomly selected from each arm).

OUTCOMES AND MEASURES

Parent-reported sleep patterns at ages 6 mo, 1 yr, 2 yr, and 2.5 yr. Sensory Processing Measure-Preschool questionnaire covering five sensory systems and higher level functions: praxis and social participation at age 2.5 yr. Relationships between sleep and sensory variables were analyzed using multiple linear regression models.

RESULTS

More problematic sleep at age 2.5 yr was associated with more difficulties in social-relational skills (p < .001), a finding supported by the longitudinal data. Longer settling times were associated with higher vision (p = .036) and touch (p = .028) sensitivities at age 2.5 yr; in the longitudinal data (ages 6 mo-2.5 yr), longer settling times were associated with more sensitive hearing (p = .042).

CONCLUSIONS AND RELEVANCE

Results support a link between sleep patterns and sensory processing difficulties in toddlers that, in some, can emerge in infancy. Practitioners should be alert to this association in young children presenting with sensory sensitivity or sleep challenges.

WHAT THIS ARTICLE ADDS

Study findings illustrate that bedtime challenges in typically developing toddlers could be related to sensory processing. A possible way to assist more sensitive children in settling to sleep is to pay attention to visual, tactile, and auditory stimuli that potentially interfere with sleep onset.

Neonatal irritable sleep-wake rhythm as a predictor of autism spectrum disorders

Recently, it has been suggested that sleep problems in autism spectrum disorder (ASD) not only are associated symptoms, but may be deeply related to ASD pathogenesis. Common clinical practice relating to developmental disorders, has shown that parents of children with ASD have often stated that it is more difficult to raise children in the neonatal period because these children exhibit sleep problems. This study investigated the possibility that abnormal neonatal sleep-wake rhythms are related to future ASD development.

We administered questionnaires to assess parent(s) of children with ASD and controls. A retrospective analysis was conducted among 121 children with ASD (94 male and 27 female children) recruited from the K-Development Support Center for Children (K-ASD), 56 children with ASD (40 male and 16 female children) recruited from the H-Children's Sleep and Development Medical Research Center (H-ASD) and 203 children (104 male and 99 female children) recruited from four nursery schools in T-city (control).

Irritable/over-reactive types of sleep-wake rhythms that cause difficulty in raising children, such as 1) frequently waking up, 2) difficulty falling asleep, 3) short sleep hours, and 4) continuous crying and grumpiness, were observed more often in ASD groups than in the control group. Additionally, the number of the mothers who went to bed after midnight during pregnancy was higher in the ASD groups than in the control group.

Sleep-wake rhythm abnormalities in neonates may be considerable precursors to future development of ASD. Formation of ultradian and postnatal circadian rhythms should be given more attention when considering ASD development. Although this is a retrospective study, the results suggest that a prospective study regarding this issue may be important in understanding and discovering intervention areas that may contribute to preventing and/or properly treating ASD.

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Neonatal irritable-type sleep-wake rhythmabnormalities are important precursors for futureASD development.

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Maternal lack of sleep and irregular lifestyle isrelated to increased risk of possibly developingfuture ASD.

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There is a possibility that proper intervention toabnormal sleep-wake rhythm may prevent thesubsequent onset of ASD.

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It is more logical to understand and interpret ASD,based on circadian rhythm and pineal glandfunction.

Dysregulation of Circadian Rhythms in Autism Spectrum Disorders

Background:

The alterations in neurological and neuroendocrine functions observed in the autism spectrum disorder (ASD) involves environmentally dependent dysregulation of neurodevelopment, in interaction with multiple coding gene defects. Disturbed sleep-wake patterns, as well as abnormal melatonin and glucocorticoid secretion, show the relevance of an underlying impairment of the circadian timing system to the behavioral phenotype of ASD. Thus, understanding the mechanisms involved in the circadian dysregulation in ASD could help to identify early biomarkers to improve the diagnosis and therapeutics as well as providing a significant impact on the lifelong prognosis.

Objective:

In this review, we discuss the organization of the circadian timing system and explore the connection between neuroanatomic, molecular, and neuroendocrine responses of ASD and its clinical manifestations. Here we propose interconnections between circadian dysregulation, inflammatory baseline and behavioral changes in ASD. Taking into account, the high relevancy of melatonin in orchestrating both circadian timing and the maintenance of physiological immune quiescence, we raise the hypothesis that melatonin or analogs should be considered as a pharmacological approach to suppress inflammation and circadian misalignment in ASD patients.

Strategy:

This review provides a comprehensive update on the state-of-art of studies related to inflammatory states and ASD with a special focus on the relationship with melatonin and clock genes. The hypothesis raised above was analyzed according to the published data.

Conclusion:

Current evidence supports the existence of associations between ASD to circadian dysregulation, behavior problems, increased inflammatory levels of cytokines, sleep disorders, as well as reduced circadian neuroendocrine responses. Indeed, major effects may be related to a low melatonin rhythm. We propose that maintaining the proper rhythm of the circadian timing system may be helpful to improve the health and to cope with several behavioral changes observed in ASD subjects.