Use of Atypical Antipsychotics in the Treatment of Autistic Disorder

Transcriptome analysis identifies an ASD-Like phenotype in oligodendrocytes and microglia from C58/J amygdala that is dependent on sex and sociability

BACKGROUND

Autism Spectrum Disorder (ASD) is a group of neurodevelopmental disorders with higher incidence in males and is characterized by atypical verbal/nonverbal communication, restricted interests that can be accompanied by repetitive behavior, and disturbances in social behavior. This study investigated brain mechanisms that contribute to sociability deficits and sex differences in an ASD animal model.

METHODS

Sociability was measured in C58/J and C57BL/6J mice using the 3-chamber social choice test. Bulk RNA-Seq and snRNA-Seq identified transcriptional changes in C58/J and C57BL/6J amygdala within which DMRseq was used to measure differentially methylated regions in amygdala.

RESULTS

C58/J mice displayed divergent social strata in the 3-chamber test. Transcriptional and pathway signatures revealed immune-related biological processes differ between C58/J and C57BL/6J amygdala. Hypermethylated and hypomethylated genes were identified in C58/J versus C57BL/6J amygdala. snRNA-Seq data in C58/J amygdala identified differential transcriptional signatures within oligodendrocytes and microglia characterized by increased ASD risk gene expression and predicted impaired myelination that was dependent on sex and sociability. RNA velocity, gene regulatory network, and cell communication analysis showed diminished oligodendrocyte/microglia differentiation. Findings were verified using Bulk RNA-Seq and demonstrated oxytocin's beneficial effects on myelin gene expression.

LIMITATIONS

Our findings are significant. However, limitations can be noted. The cellular mechanisms linking reduced oligodendrocyte differentiation and reduced myelination to an ASD phenotype in C58/J mice need further investigation. Additional snRNA-Seq and spatial studies would determine if effects in oligodendrocytes/microglia are unique to amygdala or if this occurs in other brain regions. Oxytocin's effects need further examination to understand its' potential as an ASD therapeutic.

CONCLUSIONS

Our work demonstrates the C58/J mouse model's utility in evaluating the influence of sex and sociability on the transcriptome in concomitant brain regions involved in ASD. Our single-nucleus transcriptome analysis elucidates potential pathological roles of oligodendrocytes and microglia in ASD. This investigation provides details regarding regulatory features disrupted in these cell types, including transcriptional gene dysregulation, aberrant cell differentiation, altered gene regulatory networks, and changes to key pathways that promote microglia/oligodendrocyte differentiation. Our studies provide insight into interactions between genetic risk and epigenetic processes associated with divergent affiliative behavior and lack of positive sociability.

Transcriptome Analysis Identifies An ASD-Like Phenotype In Oligodendrocytes And Microglia From C58/J Amygdala That Is Dependent On Sex and Sociability

Background

Autism Spectrum Disorder (ASD) is a group of neurodevelopmental disorders with higher incidence in males and is characterized by atypical verbal/nonverbal communication, restricted interests that can be accompanied by repetitive behavior, and disturbances in social behavior. This study investigated brain mechanisms that contribute to sociability deficits and sex differences in an ASD animal model.

Methods

Sociability was measured in C58/J and C57BL/6J mice using the 3-chamber social choice test. Bulk RNA-Seq and snRNA-Seq identified transcriptional changes in C58/J and C57BL/6J amygdala within which DMRseq was used to measure differentially methylated regions in amygdala.

Results

C58/J mice displayed divergent social strata in the 3-chamber test. Transcriptional and pathway signatures revealed immune-related biological processes differ between C58/J and C57BL/6J amygdala. Hypermethylated and hypomethylated genes were identified in C58/J versus C57BL/6J amygdala. snRNA-Seq data in C58/J amygdala identified differential transcriptional signatures within oligodendrocytes and microglia characterized by increased ASD risk gene expression and predicted impaired myelination that was dependent on sex and sociability. RNA velocity, gene regulatory network, and cell communication analysis showed diminished oligodendrocyte/microglia differentiation. Findings were verified using bulk RNA-Seq and demonstrated oxytocin's beneficial effects on myelin gene expression.

Limitations

Our findings are significant. However, limitations can be noted. The cellular mechanisms linking reduced oligodendrocyte differentiation and reduced myelination to an ASD phenotype in C58/J mice need further investigation. Additional snRNA-Seq and spatial studies would determine if effects in oligodendrocytes/microglia are unique to amygdala or if this occurs in other brain regions. Oxytocin's effects need further examination to understand its potential as an ASD therapeutic.

Conclusions

Our work demonstrates the C58/J mouse model's utility in evaluating the influence of sex and sociability on the transcriptome in concomitant brain regions involved in ASD. Our single-nucleus transcriptome analysis elucidates potential pathological roles of oligodendrocytes and microglia in ASD. This investigation provides details regarding regulatory features disrupted in these cell types, including transcriptional gene dysregulation, aberrant cell differentiation, altered gene regulatory networks, and changes to key pathways that promote microglia/oligodendrocyte differentiation. Our studies provide insight into interactions between genetic risk and epigenetic processes associated with divergent affiliative behavior and lack of positive sociability.

Practitioner's review: medication for children and adolescents with autism spectrum disorder (ASD) and comorbid conditions

Alleviating the multiple problems of children with autism spectrum disorder (ASD) and its comorbid conditions presents major challenges for the affected children, parents, and therapists. Because of a complex psychopathology, structured therapy and parent training are not always sufficient, especially for those patients with intellectual disability (ID) and multiple comorbidities. Moreover, structured therapy is not available for a large number of patients, and pharmacological support is often needed, especially in those children with additional attention deficit/hyperactivity and oppositional defiant, conduct, and sleep disorders.

From bedside to bench and back: Translating ASD models

Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.

Comorbid autism spectrum disorder and anxiety disorders: a brief review

Appearing in 40% of the cases of autism spectrum disorder (ASD), comorbid anxiety presents unique challenges for practitioners by amplifying problem behaviors such as social skills deficits, resistance to change and repetitive behaviors. Furthermore, comorbid ASD/anxiety strains familial relationships and increases parental stress. Research indicates that the neurobiological interactions between anxiety and ASD require comprehensive assessment approaches, modified cognitive behavioral therapy and carefully managed pharmacological interventions. Meta-analyses indicate that cognitive behavioral therapy with exposure is an effective treatment option when adequately accounting for social, familial and cognitive variables. The purpose of this focused review is to update readers on the latest research advances in comorbid ASD and anxiety, including prevalence, assessment, psychosocial and pharmacological treatment.

Efficacy and tolerability of pharmacotherapy options for the treatment of irritability in autistic children

Children with autism have a high rate of irritability and aggressive symptoms. Irritability or self-injurious behavior can result in significant harm to those affected, as well as to marked distress for their families. This paper provides a literature review regarding the efficacy and tolerability of pharmacotherapy for the treatment of irritability in autistic children. Although antipsychotics have not yet been approved for the treatment of autistic children by many countries, they are often used to reduce symptoms of behavioral problems, including irritability, aggression, hyperactivity, and panic. However, among antipsychotics, the Food and Drug Administration has approved only risperidone and aripiprazole to treat irritability in autism. Among atypical antipsychotics, olanzapine and quetiapine are limited in their use for autism spectrum disorders in children because of high incidences of weight gain and sedation. In comparison, aripiprazole and ziprasidone cause less weight gain and sedation. However, potential QTc interval prolongation with ziprasidone has been reported. Contrary to ziprasidone, no changes were evident in the QT interval in any of the trials for aripiprazole. However, head-to-head comparison studies are needed to support that aripiprazole may be a promising drug that can be used to treat irritability in autistic children. On the other hand, risperidone has the greatest amount of evidence supporting it, including randomized controlled trials; thus, its efficacy and tolerability has been established in comparison with other agents. Further studies with risperidone as a control drug are needed.

Repeated aripiprazole treatment causes dopamine D2 receptor up-regulation and dopamine supersensitivity in young rats

Aripiprazole is a second-generation antipsychotic that is increasingly being prescribed to children and adolescents. Despite this trend, little preclinical research has been done on the neural and behavioral actions of aripiprazole during early development. In the present study, young male and female Sprague-Dawley rats were pretreated with vehicle, haloperidol (1 mg/kg), or aripiprazole (10 mg/kg) once daily on postnatal days (PD) 10-20. After 1, 4, or 8 days (i.e. on PD 21, PD 24, or PD 28), amphetamine-induced locomotor activity and stereotypy, as well as dorsal striatal D2 receptor levels, were measured in separate groups of rats. Pretreating young rats with aripiprazole or haloperidol increased D2 binding sites in the dorsal striatum. Consistent with these results, dopamine supersensitivity was apparent when aripiprazole- and haloperidol-pretreated rats were given a test day injection of amphetamine (2 or 4 mg/kg). Increased D2 receptor levels and altered behavioral responding persisted for at least 8 days after conclusion of the pretreatment regimen. Contrary to what has been reported in adults, repeated aripiprazole treatment caused D2 receptor up-regulation and persistent alterations of amphetamine-induced behavior in young rats. These findings are consistent with human clinical studies showing that children and adolescents are more prone than adults to aripiprazole-induced side effects, including extrapyramidal symptoms.

Prosocial effects of oxytocin in two mouse models of autism spectrum disorders

Clinical evidence suggests that oxytocin treatment improves social deficits and repetitive behavior in autism spectrum disorders (ASDs). However, the neuropeptide has a short plasma half-life and poor ability to penetrate the blood-brain barrier. In order to facilitate the development of more bioavailable oxytocinergic compounds as therapeutics to treat core ASD symptoms, small animal models must be validated for preclinical screens. This study examined the preclinical utility of two inbred mouse strains, BALB/cByJ and C58/J, that exhibit phenotypes relevant to core ASD symptoms. Mice from both strains were intraperitoneally administered oxytocin, using either acute or sub-chronic regimens. Acute oxytocin did not increase sociability in BALB/cByJ; however, sub-chronic oxytocin had significant prosocial effects in both BALB/cByJ and C58/J. Increased sociability was observed 24 h following the final oxytocin dose in BALB/cByJ, while prosocial effects of oxytocin emerged 1-2 weeks post-treatment in C58/J. Furthermore, acute oxytocin decreased motor stereotypy in C58/J and did not induce hypoactivity or anxiolytic-like effects in an open field test. This study demonstrates that oxytocin administration can attenuate social deficits and repetitive behavior in mouse models of ASD, dependent on dose regimen and genotype. These findings provide validation of the BALB/cByJ and C58/J models as useful platforms for screening novel drugs for intervention in ASDs and for elucidating the mechanisms contributing to the prosocial effects of oxytocin.

Efficacy of risperidone in managing maladaptive behaviors for children with autistic spectrum disorder: a meta-analysis

INTRODUCTION

Atypical antipsychotic agents are widely used psychopharmacological interventions for autism spectrum disorders (ASDs). Among the atypical antipsychotic agents, risperidone has demonstrated considerable benefits in reducing several behavioral symptoms associated with ASDs. This meta-analysis examined research regarding the effectiveness of risperidone use among children with ASD using articles published since the year 2000.

METHODS

The database for the analyses comprised 22 studies including 16 open-label and six placebo-controlled studies. Based on the quality, sample size, and study design of studies prior to 2000, the database was then restricted to articles published after the year 2000. Effect sizes were calculated for each reported measure within a study to calculate an average effect size per study.

RESULTS

The mean effect size for the database was 1.047 and the sample weighted mean effect size was 1.108, with a variance of 0.18.

CONCLUSIONS

Outcome measures demonstrated mean improvement in problematic behaviors equaling one standard deviation, and thus current evidence supports the effectiveness of risperidone in managing behavioral problems and symptoms for children with ASD. Although Risperdal has several adverse effects, most are manageable or extremely rare. An exception is rapid weight gain, which is common and can create significant health problems. Overall, for most children with autism and irritable and aggressive behavior, risperidone is an effective psychopharmacological treatment.

Ten years of antipsychotic prescribing to children: a Canadian population-based study

OBJECTIVE

To report the prescribing of antipsychotics to the youth population of the Canadian province of Manitoba during the course of a decade.

METHODS

Use of antipsychotics in children and adolescents (aged 18 years or younger) was described using data collected from the administrative health databases of Manitoba Health and the Statistics Canada census between the fiscal years of 1999 and 2008.

RESULTS

The prevalence of antipsychotic use in this segment of the population increased with the introduction of the second-generation antipsychotics (SGAs) from 1.9 per 1000 in 1999 to 7.4 per 1000 in 2008. The male-to-female antipsychotic usage ratio increased from 1.9 to 2.7 as the male youth population represented the fastest-growing subgroup of antipsychotic users in the entire population of Manitoba. The total number of prescriptions also increased significantly despite the lack of approved indications in this population. Proportion of use remained equally split between high- and low-income users. More than 70% of antipsychotic prescriptions to children and adolescents were written by general practitioners. The most common diagnoses linked to antipsychotic use were attention-deficit hyperactivity disorder and conduct disorders. Use of antipsychotics in combination with methylphenidate increased from 13% to 43%.

CONCLUSION

Extensive off-label use of SGAs has been observed in the youth population of Manitoba for treatment of aggressive behaviours across a range of diagnoses. It is important to monitor antipsychotic prescribing to children as more reports of significant adverse events associated with antipsychotics become available.

Group swimming and aquatic exercise programme for children with autism spectrum disorders: a pilot study

OBJECTIVE

To evaluate the effectiveness of a 14-week aquatic exercise programme for children with autism spectrum disorders (ASD).

DESIGN

Non-randomized control trial.

METHODS

Twelve children participated in this pilot study with seven participants in the aquatic exercise group and five in the control group. The programme was held twice per week for 40 minutes per session. Swimming skills, cardiorespiratory endurance, muscular endurance, mobility skills and participant and parent satisfaction were measured before and after the intervention.

RESULTS

No significant between-group changes were found. Within-group improvements for swimming skills were found for the intervention group. Programme attendance was high. Parents and children were very satisfied with the programme activities and instructors.

CONCLUSIONS

This pilot programme was feasible and showed potential for improving swimming ability in children with ASD. Exercise intensity was low for some participants, most likely contributing to a lack of significant findings on fitness outcomes.

Effects of repeated and acute aripiprazole or haloperidol treatment on dopamine synthesis in the dorsal striatum of young rats: comparison to adult rats

The purpose of the present study was to determine whether repeated treatment with the D2 partial agonist aripiprazole or the D2 antagonist haloperidol alters dopamine (DA) synthesis characteristics in the dorsal striatum of young rats. To this end, rats received a daily pretreatment regimen of aripiprazole or haloperidol on postnatal days (PD) 10-20 and were tested 24 or 72 h later after an acute injection of vehicle, aripiprazole, haloperidol, or quinpirole (a D2 agonist). For comparison purposes, adult rats were pretreated with an 11-day regimen of saline or haloperidol on PD 70-80 and DA synthesis was measured after acute drug treatment on PD 83. Dorsal striatal DA synthesis was determined by measuring L-dihydroxyphenylalanine accumulation after NSD-1015 treatment. In a separate experiment, the ability of repeated drug treatment to up-regulate dorsal striatal D2 receptors was assessed in young and adult rats 72 h after drug discontinuation. The major findings of this study were that: (a) acute treatment with haloperidol and aripiprazole increased DA synthesis while quinpirole reduced it; (b) pretreatment with haloperidol and aripiprazole blunted the synthesis-modulating effects of acutely administered dopaminergic drugs; and (c) DA synthesis of young and adult rats was affected in a qualitatively similar manner by DA agonist, antagonist, and partial agonist drugs. In conclusion, results from the present study suggest that synthesis-modulating autoreceptors in the dorsal striatum are functionally mature by the end of the preweanling period and DA synthesis declines to near basal levels during the course of repeated aripiprazole treatment.

Rhabdomyolysis associated with olanzapine treatment in a child with Autism

Children with autism often display difficult behaviors including tantrums, extreme irritability, and physical aggression. There is emerging evidence that olanzapine is useful in decreasing these disruptive behaviors. The most common adverse effects are weight gain and short-term sedation. On the other hand, olanzapine rarely causes rhabdomyolysis. We report a case with rhabdomyolysis in an autistic child just after 2 doses of olanzapine treatment. Initial creatine kinase value was 30,690 IU/L (range, 5-130 U/L), and rhabdomyolysis resolved with hydration and alkalinization over 7 days. Monitoring serum creatine kinase levels may be useful in pediatric cases after initiation of olanzapine treatment.

A review of recent reports on autism: 1000 studies published in 2007

From 1000 studies published in 2007 on all aspects of autism, those that reached clear conclusions or included quantitative data were selected for this review. Possible etiologies include elemental metals, especially the inconsistent evidence regarding mercury from the vaccine preservative thimerosal, not used after 2001, and chromosomes and genes with the conclusion that autism has a complex genetic architecture. Also, various parental conditions are considered, as are many different abnormalities in the central nervous system, especially underconnectivity within the cortex. Furthermore, deficiencies in mirror neurons have been proposed, leading to the "theory of mind" explanation that autistic children tend to disregard others. In addition, various global deficiencies, like an increase in inhibitory synaptic transmission, are proposed. Characteristics of these children include selective (inward) attention; underresponsiveness; stereotyped repetitive motor behavior; increased head size, weight, and height; various cognitive and communicative disorders; and also epilepsy. Therapy has emphasized risperidone, but some atypical antipsychotic medications have been helpful, as have robotic aids, massage, hyperbaric oxygen, and music. Nearly every conceivable problem that a child could have can be observed in these unfortunate children.

Control of psychomotor agitation and aggressive behavior in patients with autistic disorder: a retrospective chart review

OBJECTIVE: To evaluate the efficacy of pharmacotherapy on the symptoms of psychomotor agitation and aggressive behavior in a sample of patients with autistic spectrum disorder. METHOD: The charts of all patients with a diagnosis of autistic spectrum disorder, receiving care for psychomotor agitation and/or aggressive behavior in two psychiatric outpatient departments between 2001 and 2006, were reviewed. The Clinical Global Impression-Severity and -Improvement scales (CGI-S and CGI-I) were applied to the data retrieved from the charts. RESULTS: The majority of the 26 patients included were treated with second-generation antipsychotics. A positive, statistically significant correlation was found between the implementation of pharmacotherapy and a reduction in CGI-S scores (p<0.05). Treatment response in patients with no mental retardation was better than in those mentally retarded (p<0.05). The majority of patients in whom clinical improvement was found following implementation of treatment had participated in at least one form of intervention therapy in addition to the principal treatment (p<0.05). CONCLUSION: Second-generation antipsychotics seem to reduce psychomotor agitation and aggressive behavior in patients with autistic spectrum disorder; however, further studies are required to evaluate the side effects of these drugs in relation to their beneficial effects.

Buspirone for autistic disorder in a woman with an intellectual disability

OBJECTIVE

To describe a case of an intellectually disabled patient who was diagnosed with autistic disorder (AD) and responded positively to buspirone, demonstrated by a reduction in target behaviors of self-injury, property destruction, and physical aggression.

CASE SUMMARY

A 33-year-old, white, nonverbal, profoundly intellectually impaired woman (IQ <20-25), residing in a state-run facility, exhibited worsening aggressive behaviors associated with AD. These behaviors were characterized by a history of self-injurious behavior (eg, slapping and scratching herself); property destruction, including breaking windows; and head butting of staff and peers. Additional diagnoses included a seizure disorder, hyperprolactinemia, and osteoporosis. At the time of admission, her drug regimen included 3 atypical antipsychotic agents: risperidone, clozapine, and aripiprazole. Antipsychotic agents have been reported to lower the seizure threshold, and elevated prolactin levels have been associated with risperidone use. Aripiprazole and clozapine were discontinued on admission, and risperidone was discontinued one month later following increased behavioral deterioration. Buspirone was considered an appropriate replacement medication, as it has not been associated with elevated prolactin levels or a lowered seizure threshold, and was initiated at 15 mg/day. Significant reductions in aggression were noted following titration to a total daily dose of 90 mg.

DISCUSSION

Buspirone is approved for treatment of generalized anxiety disorder in adults. Dopaminergic agonist/antagonist actions have been reported with use of higher doses. These receptor effects have been beneficial for aggressive behaviors in the AD population that were exhibited by our patient, but effectiveness for aggression in the intellectually disabled population is uncertain. In our patient, problematic behaviors associated with AD responded positively to buspirone.

CONCLUSIONS

The reduction in target aggressive behaviors achieved with buspirone therapy allowed other treatment interventions to proceed more effectively in our patient. Clinicians may wish to consider use of buspirone in patients with AD who do not respond to or have risk factors for use of other therapy.