Urinary cortisol circadian rhythm in a group of high-functioning children with autism

Development of the circadian oscillator during differentiation of mouse embryonic stem cells in vitro

The molecular oscillations underlying the generation of circadian rhythmicity in mammals develop gradually during ontogenesis. However, the developmental process of mammalian cellular circadian oscillator formation remains unknown. In differentiated somatic cells, the transcriptional-translational feedback loops (TTFL) consisting of clock genes elicit the molecular circadian oscillation. Using a bioluminescence imaging system to monitor clock gene expression, we show here that the circadian bioluminescence rhythm is not detected in the mouse embryonic stem (ES) cells, and that the ES cells likely lack TTFL regulation for clock gene expression. The circadian clock oscillation was induced during the differentiation culture of mouse ES cells without maternal factors. In addition, reprogramming of the differentiated cells by expression of Sox2, Klf4, Oct3/4, and c-Myc genes, which were factors to generate induced pluripotent stem (iPS) cells, resulted in the re-disappearance of circadian oscillation. These results demonstrate that an intrinsic program controls the formation of the circadian oscillator during the differentiation process of ES cells in vitro. The cellular differentiation and reprogramming system using cultured ES cells allows us to observe the circadian clock formation process and may help design new strategies to understand the key mechanisms responsible for the organization of the molecular oscillator in mammals.

Absence of a normal cortisol awakening response (CAR) in adolescent males with Asperger syndrome (AS)

In addition to abnormalities in social and communication development, a 'need for sameness' and 'resistance to change' are features of autistic spectrum disorders first identified by Kanner in 1943. Our ability to react to change is modulated by the hypothalamic-pituitary-adrenal (HPA) axis, a feature of which is a dramatic increase in cortisol upon waking, the Cortisol Awakening Response (CAR). This study examined whether the CAR was evident in 20 adolescent males with Asperger Syndrome (AS) and 18 age-matched typically developing (TD) controls (aged 11-16). Whilst a significant CAR was evidenced in the TD control group, this was not the case for those with AS. A normal diurnal decrease in cortisol, however, was evident in both groups. The implication that individuals with AS may have an impaired response to change in their environment due to a refractory HPA axis is discussed.

Comparing cortisol, stress, and sensory sensitivity in children with autism

Previously we reported that children with autism show significant variability in cortisol. The current investigation was designed to extend these findings by exploring plausible relationships between cortisol and psychological measures of stress and sensory functioning. Salivary cortisol values for diurnal rhythms and response to stress in children with and without autism were compared to parent-report measures of child stress, the Stress Survey Schedule (SSS), sensory functioning, Short Sensory Profile (SSP), and Parenting Stress Index. In autism, a negative relationship between morning cortisol and the SSS revealed that higher observed symptoms of stress were related to lower cortisol. Lower cortisol is seen in conditions of chronic stress and in social situations characterized by unstable social relationships. Sensory sensitivity painted a more complicated picture, in that some aspects of SSP were associated with higher while others were associated with lower cortisol. We propose that increased sensory sensitivity may enhance the autistic child's susceptibility to the influence of zeitgeibers reflected in variable cortisol secretion. Evening cortisol was positively associated with SSS such that the higher the level of evening cortisol, the higher the child's parent-reported daily stress, especially to changes, such as in daily routine. Regarding the response to stress, the psychological and parent variables did not differentiate the groups; rather, discrete subgroups of cortisol responders and nonresponders were revealed in both the autism and neurotypical children. The results support a complex interplay between physiological and behavioral stress and sensory sensitivity in autism and plausible developmental factors influencing stress reactivity across the groups.

Porphyrinuria in childhood autistic disorder is not associated with urinary creatinine deficiency

BACKGROUND

Urinary metabolite measurements are often normalized to levels of the ubiquitous metabolite creatinine (CRT) to take account of variations in fluid export. Following CRT normalization, excesses of porphyrins and isoprostanes have been reported in the urines of children with neurodevelopmental disorders. It was suggested (Whiteley et al., 2006, Pediatr. Int. 2006; 48: 292-297) that urinary CRT levels may be depressed in children with autism spectrum disorders. This prompted re-evaluation of CRT levels in such children.

METHODS

First matinal urinary CRT levels were compared between subjects in different diagnostic categories including autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and hyperactivity, before and after correction for age and gender. A larger reference group, consisting of subjects with unrelated disorders and Asperger disorder, with no reported porphyrin excess, was also compared to the group with autistic disorder, both for CRT and for porphyrin (coproporphyrin, COPRO) excess.

RESULTS

No significant difference in CRT was observed between any of the categories analyzed, also when corrected for age and gender. In contrast, urinary COPRO levels were significantly higher in autistic disorder versus reference groups, either when expressed as absolute values (independent of CRT levels) or when normalized to CRT.

CONCLUSIONS

These data do not support a systematic reduction in urinary CRT levels in subjects with autism spectrum disorders including autistic disorder and PDD-NOS. Urinary COPRO excess in autistic disorder was not associated with or consequent upon urinary CRT deficiency. Differences between affected and control subjects in age and sampling time, as reported by Whiteley et al., may underlie the apparent CRT reduction.

Prenatal stress and risk for autism

This paper reviews several converging lines of research that suggest that prenatal exposure to environmental stress may increase risk for Autistic Disorder (AD). We first discuss studies finding that prenatal exposure to stressful life events is associated with significantly increased risk of AD, as well as other disorders, such as schizophrenia and depression. We then review evidence from animal and human studies that prenatal stress can produce both (a) abnormal postnatal behaviors that resemble the defining symptoms of AD, and (b) other abnormalities that have elevated rates in AD, such as learning deficits, seizure disorders, perinatal complications, immunologic and neuroinflammatory anomalies, and low postnatal tolerance for stress. We explain why an etiologic role for prenatal stress is compatible with genetic factors in AD, and describe how stress can disrupt fetal brain development. Finally, we discuss implications for understanding underlying processes in AD, including potential gene-environment interactions, and developing new therapies and early prevention programs.

Effect of social familiarity on salivary cortisol and self-reports of social anxiety and stress in children with high functioning autism spectrum disorders

This study examined the effect of social familiarity on salivary cortisol and social anxiety/stress for a sample of children with high-functioning autism spectrum disorders. The relationship between self-reported social anxiety/stress and salivary cortisol was also examined. Participants interacted with a familiar peer on one occasion and an unfamiliar peer on another occasion. Data were collected using salivary cortisol and a scale measuring subjective stress. Results indicated a significant condition by order interaction for salivary cortisol levels, while self-rated stress did not differ significantly across situations. A mild-moderate correlation was found between self-reported distress and salivary cortisol within each condition. Examination of self-rated distress vs. cortisol scatter plots suggested a more complex relationship than the correlation coefficient could adequately convey.

Slower cortisol response during ACTH stimulation test in autistic children

Autism is a hereditary, pervasive neurodevelopmental disorder that starts early in life. The main characteristics of the autism are impairment in social interactions, difficulties in adapting to novel environmental situations and improper reaction to stress. Since the Hypothalamic-Pituitary-Adrenocortical (HPA) axis plays a key role in the response to stress and because the previous research found abnormalities in HPA system, we conducted a study to test several elements of the HPA axis. Because autism is a heritable disorder, autistic subjects were studied as well as their parents. Cortisol circadian rhythm, cortisol daily secretion and its suppression response to dexamethasone had been measured from saliva or urine samples of the autistic children and their parents. Cortisol secretion response after ACTH stimulation was done with the autistic children only. The cortisol elevation after ACTH stimulation among the autistic individuals was slower (P = 0.017) than in healthy controls. No differences were found in salivary cortisol circadian rhythm or suppression response, as well as in cortisol daily excretion. These data indicate that, compared to healthy subjects, autistic individuals have fine differences in cortisol response to ACTH stimulation or possibly to other types of stress.

Reduced Plasma Apelin Levels in Patients with Autistic Spectrum Disorder

BACKGROUND

Dysregulation of the vasopressin (AVP) system has been implicated in the pathogenesis of autistic spectrum disorder (ASD). Apelin is a recently discovered neuropeptide that could counteract AVP actions and whose receptors are colocalized with vasopressin in hypothalamic magnocellular neurons. Aims of the present study were to investigate circulating levels of apelin in patients with ASD and to assess their correlation with plasma AVP concentrations.

METHODS

Plasma levels of apelin and AVP were measured in a total of 18 patients with ASD and 21 age- and gender-matched healthy comparison subjects. The Childhood Autism Rating Scale (CARS) was used to assess the severity of autistic symptoms.

RESULTS

Significantly reduced levels of apelin (p < 0.001) and elevated concentrations of AVP (p = 0.02) were found in ASD patients as compared to controls. Additionally, a significant inverse correlation between apelin and AVP levels was found within the ASD group (r = -0.61; p = 0.007), but not in healthy participants (r = -0.26; p = 0.25). Multivariate linear regression analysis showed that only AVP concentrations independently predicted apelin values in ASD individuals (beta = -0.42, t = 2.63, p = 0.014). No correlation was seen between apelin levels and CARS scores (r = -0.10; p = 0.68).

CONCLUSIONS

Our findings of a significantly reduced peripheral level of apelin coupled with elevated AVP point to a subtle but definite vasopressinergic dysfunction in autism that could play a role in the etiopathophysiology of this disorder in humans.

Objective investigation of the sleep-wake cycle in adults with intellectual disabilities and autistic spectrum disorders

BACKGROUND

Disturbances in circadian rhythm functioning, as manifest in abnormal sleep-wake cycles, have been postulated to be present in people with autistic spectrum disorders (ASDs). To date, research into the sleep-wake cycle in people with ASDs has been primarily dependant on third-party data collection.

METHOD

The utilization of non-invasive objective recording technologies such as actigraphy permits investigation of both sleep and circadian rhythm functioning in people with ASDs, together with the collection of data on daytime activity.

RESULTS

Data were collected from 31 participants with intellectual disabilities living in supported community-based residential provision aged between 20 and 58 years, of whom 14 had an ASD. Analysis indicated that there were no significant differences in sleep patterns and circadian rhythm function between those participants with an ASD and those without.

CONCLUSIONS

The mean scores of the participants as a whole indicated abnormalities in the two key circadian rhythm parameters of interdaily stability and intradaily variability. The implications of these findings for both clinical practice and theory are discussed.

Macrocephaly and the control of brain growth in autistic disorders

Autism is a childhood-onset neuropsychiatric disorder characterized by marked impairments in social interactions and communication, with restricted stereotypic and repetitive patterns of behavior, interests, and activities. Genetic epidemiology studies indicate that a strong genetic component exists to this disease, but these same studies also implicate significant environmental influence. The disorder also displays symptomatologic heterogeneity, with broad individual differences and severity on a graded continuum. In the search for phenotypes to resolve heterogeneity and better grasp autism's underlying biology, investigators have noted a statistical overrepresentation of macrocephaly, an indicator of enlarged brain volume. This feature is one of the most widely replicated biological findings in autism. What then does brain enlargement signify? One hypothesis invoked for the origin of macrocephaly is a reduction in neuronal pruning and consolidation of synapses during development resulting in an overabundance of neurites. An increase in generation of cells is an additional mechanism for macrocephaly, though it is less frequently discussed in the literature. Here, we review neurodevelopmental mechanisms regulating brain growth and highlight one underconsidered potential causal mechanism for autism and macrocephaly--an increase in neurogenesis and/or gliogenesis. We review factors known to control these processes with an emphasis on nuclear receptor activation as one signaling control that may be abnormal and contribute to increased brain volume in autistic disorders.

Further examination of relationships between life events and psychiatric symptoms in adults with intellectual disability

BACKGROUND

It has been proposed that people with intellectual disability (ID) might be similar to the general population in the way they respond to significant life events. Some preliminary findings have demonstrated that adults with ID who have experienced recent life events have an increased probability of having psychiatric problems. The aims of the present study were to determine whether previous findings can be replicated, and to examine the influence of additional diagnoses associated with ID on the strength of relationships between life event frequency and psychiatric problems.

METHODS

Adults with ID (n = 624), living either in staffed community accommodation or in family or foster homes, were assessed on the Developmental Behaviour Checklist for Adults (DBC-A) and a 37-item life events checklist. Carers who knew the person well acted as proxy informants.

RESULTS

People living in staffed accommodation experienced more life events than people living with natural or foster families. Life event frequency predicted DBC-A total score, five of six sub-scale scores, and caseness status, after significant demographic factors were taken into account. However, the strength of correlations between life event frequency and DBC-A total score varied among sub-groups identified by type of developmental disability and level of ID.

CONCLUSIONS

Weak but significant associations between emotional and behavioural problems and life events experienced by adults with ID were demonstrated, but it was also shown that the strength of such associations varies among sub-groups of this heterogeneous population. Future research needs to take account of the circumstances surrounding the life changes, the period of time over which changes might have taken place, and the meaning that the person might attach to the changes. Research into the causal relationship between exposure to life events and the onset of psychiatric problems is also warranted.

Glucocorticoid receptor antagonists: new tools to investigate disorders characterized by cortisol hypersecretion

Increased cortisol levels have been observed in patients suffering from a number of metabolic and psychiatric disorders. In some of these disorders a causal relationship has been suggested between the increased cortisol secretion and the observed clinical phenomena. Glucocorticoid receptor antagonists which block cortisol effects might have a benefit in both the diagnosis and treatment of these disorders. Selective glucocorticoid receptor antagonists with in vivo potency have not been described thus far, partly due to the similarity between the glucocorticoid and progesterone receptors. In the present studies, we report on three different chemical classes derived from the glucocorticoid/progestagen antagonist RU486. Selected compounds from the classes 11-monoaryl steroids, 11,21-bisaryl steroids and 11-aryl, 16-hydroxy steroids proved to be selective glucocorticoid receptor binders with in vivo antagonistic activity. Most compounds were able to pass the blood-brain barrier. These compounds offer the opportunity to investigate and possibly treat patients with a disturbed hypothalamus-pituitary-adrenal axis without side effects caused by an antiprogestagenic action.

Lower cortisol and higher ACTH levels in individuals with autism

Blood concentrations of pituitary hormones adrenocorticotropin (ACTH), prolactin, growth hormone, and adrenal hormone-cortisol were measured in 36 autistic and 27 control individuals. Individuals with autism had significantly lower serum concentrations of cortisol (p < 10(-6)), and significantly higher concentrations of ACTH (p = 0.002) than control age- and sex-matched subjects. Also, prolactin concentrations in autistic patients with epilepsy were significantly higher when compared with normal subjects. The observed hormonal changes may indicate dysfunction of the hypothalamo-pituitary-adrenal axis in individuals with autism.

Plasma beta-endorphin, adrenocorticotropin hormone, and cortisol in autism

Plasma levels of the hypothalamo-pituitary-adrenal axis hormones beta-endorphin (BE), adrenocorticotropin hormone (ACTH), and cortisol were measured in autistic (N = 48), mentally retarded/cognitively impaired (MR/CI, N = 16), and normal control (N = 26) individuals. Comparison of log transformed data from the three groups revealed that levels of BE and ACTH were significantly higher (p < .05) in the autistic individuals than in normal controls. The higher means in the autistic group were due to significantly higher plasma levels of BE and ACTH, indices of acute stress response, in the more severely affected individuals. The data support the idea that individuals with severe autism have a heightened response to acute stressors rather than chronic hyperarousal or elevated basal stress response system functioning.

Autism and autistic-like disorders: the hypothalamic-pituita-ry-adrenal system as a model for research

In this article an overview is given of the differential diagnosis of autism and autistic-like disorders. The diagnosis of the so-called 'Multiple Complex Developmental Disorders' (MCDD) as a distinct entity is discussed in relation to autism and schizophrenia. Biological research and the relevance of results until recently are discussed. Finally, the importance of the hypothalamic-pituitary-adrenal system (HPA system) as a model for research is proposed. Research on the flexibility of this system may contribute in understanding the ways of stress processing in disorders like autism, MCDD and schizophrenia.

Brief report: circadian melatonin, thyroid-stimulating hormone, prolactin, and cortisol levels in serum of young adults with autism

An abnormal circadian pattern of melatonin was found in a group of young adults with an extreme autism syndrome. Although not out of phase, the serum melatonin levels differed from normal in amplitude and mesor. Marginal changes in diurnal rhythms of serum TSH and possibly prolactin were also recorded. Subjects with seizures tended to have an abnormal pattern of melatonin correlated with EEG changes. In others, a parallel was evidenced between thyroid function and impairment in verbal communication. There appears to be a tendency for various types of neuroendocrinological abnormalities in autistics, and melatonin, as well as possibly TSH and perhaps prolactin, could serve as biochemical variables of the biological parameters of the disease.

The sleep/wake rhythm in children with autism

The sleep patterns of two groups of children with autism, one with moderate to severe intellectual handicap, and one with mild handicap to normal IQ level, were compared with those of children without autism. Parents completed 14 day sleep diaries and questionnaires. Results suggested that at some stage during childhood, particularly under 8 years of age, the majority of children with autism will experience sleep problems. These problems are likely to be severe in many cases and will generally include one or more of: extreme sleep latencies; lengthy periods of night waking, shortened night sleep; and early morning waking. Such problems may have some specificity for autism as they appear to be rare in non-handicapped children and in children with mild degrees of intellectual handicap. It is likely that sleep problems in early childhood are related to the severe social difficulties present in autism and the consequent inability of these children to use social cues to synchronize their sleep/wake cycle. Continued sleep difficulties at older ages and with higher IQ may also be related to arousal and anxiety factors.