Pharmacological Intervention in Children with Autism Spectrum Disorder with Standard Supportive Therapies Significantly Improves Core Signs and Symptoms: A Single-Center, Retrospective Case Series

The complex interplay between autism spectrum disorder and gut microbiota in children: A comprehensive review

Autism spectrum disorder (ASD) is characterized by defects in social communication and interaction along with restricted interests and/or repetitive behavior. Children with ASD often also experience gastrointestinal (GI) problems in fact incidence of GI problems in ASD is estimated up to 80 percent. Intestinal microbiota, which is a collection of trillions of microorganisms both beneficial and potentially harmful bacteria living inside the gut, has been considered one of the key elements of gut disorders. The goal of this review is to explore potential link between gut microbiota and ASD in children, based on the recently available data. This review discusses recent advances in this rapidly expanding area of neurodevelopmental disorders, which focuses on what is known about the changes in composition of gut bacteria in children with ASD, exploration of possible mechanisms via which gut microbiota might influence the brain and thus lead to appearance of ASD symptoms, as well as potential treatments that involve modulation of gut flora to improve symptoms in children with ASD, i.e., probiotics, postbiotics or changes in the diet. Of course, it's important to keep in mind inherent difficulties in proving of existence of causal relationships between gut bacteria and ASD. There are significant gaps in understanding of the mechanism of gut-brain axis and the mechanisms that underlie ASD. Standardized approaches for research in this area are needed. This review would provide an overview of this exciting emerging field of research.

The dopamine hypothesis of autism spectrum disorder: A comprehensive analysis of the evidence

Despite intensive research into the etiopathogenesis of autism spectrum disorder (ASD), limited progress has been achieved so far. Among the plethora of models seeking to clarify how ASD arises, a coherent dopaminergic model was lacking until recently. In 2017, we provided a theoretical framework that we designated "the dopamine hypothesis of ASD". In the meantime, numerous studies yielded empirical evidence for this model. 4 years later, we provided a second version encompassing a refined and reconceptualized framework that accounted for these novel findings. In this chapter, we will review the evidence backing the previous versions of our model and add the most recent developments to the picture. Along these lines, we intend to lay out a comprehensive analysis of the supporting evidence for the dopamine hypothesis of ASD.

Analysis of neurotransmitters validates the importance of the dopaminergic system in autism spectrum disorder

BACKGROUND

The reasons behind the cardinal symptoms of communication deficits and repetitive, stereotyped behaviors that characterize autism spectrum disorder (ASD) remain unknown. The dopamine (DA) system, which regulates motor activity, goal-directed behaviors, and reward function, is believed to play a crucial role in ASD, although the exact mechanism is still unclear. Investigations have shown an association of the dopamine receptor D4 (DRD4) with various neurobehavioral disorders.

METHODS

We analyzed the association between ASD and four DRD4 genetic polymorphisms, 5' flanking 120-bp duplication (rs4646984), rs1800955 in the promoter, exon 1 12 bp duplication (rs4646983), and exon 3 48 bp repeats. We also examined plasma DA and its metabolite levels, DRD4 mRNA expression, and correlations of the studied polymorphisms with these parameters by case-control comparative analyses. The expression of DA transporter (DAT), which is important in regulating the circulating DA level, was also evaluated.

RESULTS

A significantly higher occurrence of rs1800955 "T/TT" was observed in the probands. ASD traits were affected by rs1800955 "T" and the higher repeat alleles of the exon 3 48 bp repeats, rs4646983 and rs4646984. ASD probands exhibited lower DA and norepinephrine levels together with higher homovanillic acid levels than the control subjects. DAT and DRD4 mRNA expression were down-regulated in the probands, especially in the presence of DAT rs3836790 "6R" and rs27072 "CC" and DRD4 rs4646984 higher repeat allele and rs1800955 "T".

CONCLUSION

This pioneering investigation revealed a positive correlation between genetic variants, hypodopaminergic state, and impairment in socio-emotional and communication reciprocity in Indian subjects with ASD, warranting further in-depth analysis.

Therapeutic Impacts of Hyperbaric Oxygen Therapy and Risperidone on Children with Autism: A Clinical Trial

Introduction

In this research, we investigated any possible effect of receiving hyperbaric oxygen therapy (HBOT) or risperidone on the core symptoms of autism in children diagnosed with autism spectrum disorder (ASD).

Methods

This study was a randomized, controlled clinical trial in Minia and Assiut University hospitals in Egypt with three parallel groups. One hundred and eighty children with autism, aged 5-8 years were divided into three equal groups (n=60). Group 1 (G1) received 40 sessions of HBOT within two months, group 2 (G2) received risperidone (dose: 0.25 mg per day in children weighing less than 20 kg and 0.5 mg per day in cases weighing more) for six months, and group 3 (G3) as the control group, received a placebo for six months. The assessment was done using childhood autism rating scale (CARS) and autism treatment evaluation checklist (ATEC) at the beginning of the study (baseline) and after one year.

Results

The mean total CARS and ATEC scores significantly decreased (improved) by varying degrees in the three groups after a year of follow-up compared to the baseline scores, but the best results were found in G1, G2, and G3, respectively.

Conclusion

Using HBOT or risperidone is effective in treating the core symptoms of autism in children diagnosed with autism spectrum disorder, but using HBOT gives better results than risperidone therapy.

Highlights

Non-pharmacologic therapy can be used for the treatment of the core symptoms of autism.Both hyperbaric oxygen therapy and risperidone reduce the core symptoms of autism.Hyperbaric oxygen therapy gives better effects than risperidone in reducing the core symptoms of autism.

Plain Language Summary

Since the long-term use of drug therapy in children with autism leads to the occurrence of side effects in addition to the difficulty in complying with the drugs for long-term use, efforts have begun to use non-traditional alternative treatments, such as hyperbaric oxygen therapy. The current study assessed the therapeutic effect of hyperbaric oxygen therapy and risperidone on the core symptoms of autism. The results revealed that both hyperbaric oxygen therapy and risperidone reduced the core symptoms of autism, but hyperbaric oxygen therapy gave better therapeutic results than risperidone.

BDNF, proBDNF and IGF-1 serum levels in naïve and medicated subjects with autism

Brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) promote the development and maintenance of neural circuits. Alterations in these factors might contribute to autism spectrum disorder (ASD). We asked whether serum BDNF, proBDNF, and IGF-1 levels are altered in an ASD population compared to controls. We measured serum BDNF, proBDNF, and IGF-1 immunoreactive protein in boys and girls aged 5–15 years old with mild to moderate ASD and non-autistic controls by ELISA. IGF-1 was increased in ASD serum compared to controls and was correlated with age and with CARS scores. Serum BDNF levels did not differ between groups, however, proBDNF serum levels were decreased in subjects with ASD compared to non-autistic controls. Medicated, but not unmedicated, ASD subjects exhibited lower serum proBDNF levels compared to controls, while neither IGF-1 nor BDNF levels differed between treatment groups. These data support the involvement of proBDNF and IGF-1 in the pathogenesis and treatment of autism.

GABA Receptor SNPs and Elevated Plasma GABA Levels Affect the Severity of the Indian ASD Probands

Altered signaling of the chief inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), has been speculated in the etiology of autism spectrum disorder (ASD). We have investigated the association of six GABA_A-receptor genetic variants and plasma GABA levels with ASD. Subjects were recruited based on the DSM, and CARS2-ST and ADI-R assessed disease severity. Peripheral blood was collected from the ASD probands (N = 251), their parents, and ethnically matched controls (N = 347). A positive correlation between the CARS2-ST and ADI-R scores was observed; domain scores of ADI-R were higher in the severe group categorized by the CARS2-ST. GABRB3 rs1432007 "A," GABRG3 rs897173 "A," and GABRA5 rs140682 "T" showed significant association with ASD. Trait scores were influenced by rs1432007 "AA" and rs140682 "TT." GABA level was significantly higher in the probands than the age-matched controls. Our findings indicate an influence of GABA in the etiology of ASD in the Indian probands.

Core Signs and Symptoms in Children with Autism Spectrum Disorder Improved after Starting Risperidone and Aripiprazole in Combination with Standard Supportive Therapies: A Large, Single-Center, Retrospective Case Series

Background: There are a number of medications prescribed to address comorbid challenging behaviors in children with autism spectrum disorder (ASD), including risperidone and aripiprazole. This retrospective case series reports the use of these drugs in children aged 2 to 13 years. Methodology: A total of 82 children (mean age, 5 years; 79% male) with ASD treated at the Kids Neuro Clinic and Rehab Center in Dubai between January 2020 and September 2021 were included in this retrospective case series. All patients had comorbid challenging behaviors that were resistant to standard supportive therapies alone and warranted pharmacological intervention. The Childhood Autism Rating Scale—2nd Edition Standard form (CARS2-ST) and the Clinical Global Impression (CGI)—Severity (CGI-S) and CGI—Improvement (CGI-I) scales were used to assess the severity of ASD at baseline and to monitor response to treatment with risperidone or aripiprazole. Results: Besides the expected improvement in comorbid challenging behaviors, 79/82 patients (96%) attained a CGI-I score of 2 or 1 following treatment, and 35/82 patients (43%) achieved both a CGI-I score of 1 and minimal-to-no symptoms as per the CARS2-ST test, with complete resolution of their ASD signs and symptoms. The differences in the overall mean CARS2-ST and CGI-S scores pre- and post-treatment were statistically significant (Z = −7.86, p < 0.0001 for both), with pre- and post-treatment mean values of 42 and 23 for CARS2-ST, respectively, and 6 and 2 for CGI-S, respectively. The main side effects were asymptomatic elevated prolactin (n = 12) and excessive weight gain (n = 2). Conclusions: ASD core symptoms and comorbid behaviors in young children improved following chronic treatment with antipsychotic medications, either with or without medications for attention deficit hyperactivity disorder, when combined with standard supportive therapies. Double-blind, placebo-controlled clinical trials are needed to verify these findings.

Functional SLC6A3 polymorphisms differentially affect autism spectrum disorder severity: a study on Indian subjects

Imbalance in dopamine (DA) signaling is proposed to play a potential role in the etiology of Autism spectrum disorder (ASD) since, as a neuromodulator, DA regulates executive function, motor activity, social peering, attention as well as perception and subjects with ASD often exhibit deficit in these traits. Level of DA in the synaptic cleft is maintained by dopamine transporter (DAT) and hence, to identify the role of DAT in ASD, we have analyzed four functional genetic variants, rs28363170, rs3836790, rs2652511, rs27072, in nuclear families with ASD probands. Subjects were diagnosed based on Diagnostic and Statistical Manual for Mental Disorders and trait severity was assessed by Childhood Autism Rating Scale 2-Standard test. Informed written consent was obtained from the parents/care givers before recruitment followed by collection of peripheral blood for genomic DNA isolation. Target sites were investigated by PCR-based methods and data obtained was analyzed by population- as well as family-based statistical methods. Case-control analysis revealed significant higher frequencies of 9 repeat (9R) and 5 repeat (5R) alleles of rs28363170 and rs3836790 respectively in the ASD probands. Family-based analysis showed statistically significant higher paternal transmission of rs28363170 9R and rs2652511 T alleles. In the presence of rs28363170 9R, rs27072 C, rs3836790 6R6R, and rs2652511 CC variants, trait scores were higher. Studied variants showed independent as well as interactive effects, which varied based on gender of the probands. We infer that altered DA availability mediated through DAT may affect autistic traits warranting further in depth investigation in the field.

The Dopamine Hypothesis of Autism Spectrum Disorder Revisited: Current Status and Future Prospects

Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders characterized by social deficits and stereotyped behaviors. Despite intensive research, its etiopathogenesis remains largely unclear. Although studies consistently reported dopaminergic anomalies, a coherent dopaminergic model of ASD was lacking until recently. In 2017, we provided a theoretical framework for a "dopamine hypothesis of ASD" which proposed that autistic behavior arises from a dysfunctional midbrain dopaminergic system. Namely, we hypothesized that malfunction of 2 critical circuits originating in the midbrain, that is, the mesocorticolimbic and nigrostriatal pathways, generates the core behavioral features of ASD. Moreover, we provided key predictions of our model along with testing means. Since then, a notable number of studies referenced our work and numerous others provided support for our model. To account for these developments, we review all these recent data and discuss their implications. Furthermore, in the light of these new insights, we further refine and reconceptualize our model, debating on the possibility that various etiologies of ASD converge upon a dysfunctional midbrain dopaminergic system. In addition, we discuss future prospects, providing new means of testing our hypothesis, as well as its limitations. Along these lines, we aimed to provide a model which, if confirmed, could provide a better understanding of the etiopathogenesis of ASD along with new therapeutic strategies.

Risperidone or Aripiprazole Can Resolve Autism Core Signs and Symptoms in Young Children: Case Study

Risperidone and aripiprazole are approved by the USA Food and Drug Administration for the treatment of irritability and aggression in children from the ages of 5 and 6 years, respectively. However, there are no approved medications for the treatment of autism spectrum disorder (ASD) core signs and symptoms. Nevertheless, early intervention is recognized as key to improving long-term outcomes. This retrospective case study included 10 children (mean age, 2 years 10 months) with ASD who presented with persistent irritability and aggression before 4 years of age that was unresponsive to behavioral interventions and sufficiently severe to consider pharmacological intervention with risperidone or aripiprazole combined with standard supportive therapies. Besides ameliorating comorbid behaviors, improvement was observed in ASD core signs and symptoms for all patients, with minimal-to-no symptoms observed in 60% of patients according to the Childhood Autism Rating Scale 2-Standard Test and Clinical Global Impression scales. Excessive weight gain in two patients was the only adverse effect observed that required intervention. This is the first study to suggest that ASD can potentially be treated in very young children (<4 years). Clinical trials are urgently required to validate these findings among this pediatric population.