Galantamine efficacy and tolerability as an augmentative therapy in autistic children: A randomized, double-blind, placebo-controlled trial

The pediatric psychopharmacology of autism spectrum disorder: A systematic review - Part II: The future

Part I of this systematic review summarized the state-of-the-art of pediatric psychopharmacology for Autism Spectrum Disorder (ASD), a severe and lifelong neurodevelopmental disorder. The purpose of this Part II follow-up article is to provide a systematic overview of the experimental psychopharmacology of ASD. To this aim, we have first identified in the Clinicaltrials.gov website all the 157 pharmacological and nutraceutical compounds which have been experimentally tested in children and adolescents with ASD using the randomized placebo-controlled trial (RCT) design. After excluding 24 drugs already presented in Part I, a systematic review spanning each of the remaining 133 compounds was registered on Prospero (ID: CRD42023476555), performed on PubMed (August 8, 2024), and completed with EBSCO, PsycINFO (psychology and psychiatry literature) and the Cochrane Database of Systematic reviews, yielding a total of 115 published RCTs, including 57 trials for 23 pharmacological compounds and 48 trials for 17 nutraceuticals/supplements. Melatonin and oxytocin were not included, because recent systematic reviews have been already published for both these compounds. RCTs of drugs with the strongest foundation in preclinical research, namely arbaclofen, balovaptan and bumetanide have all failed to reach their primary end-points, although efforts to target specific patient subgroups do warrant further investigation. For the vast majority of compounds, including cannabidiol, vasopressin, and probiotics, insufficient evidence of efficacy and safety is available. However, a small subset of compounds, including N-acetylcysteine, folinic acid, l-carnitine, coenzyme Q10, sulforaphane, and metformin may already be considered, with due caution, for clinical use, because there is promising evidence of efficacy and a high safety profile. For several other compounds, such as secretin, efficacy can be confidently excluded, and/or the data discourage undertaking new RCTs. Part I and Part II summarize "drug-based" information, which will be ultimately merged to provide clinicians with a "symptom-based" consensus statement in a conclusive Part III, with the overarching aim to foster evidence-based clinical practices and to organize new strategies for future clinical trials.

Navigating agitation in neurodevelopmental disorders: A comparative study of pharmacotherapies via network meta-analysis in children and adults with autism spectrum disorder or intellectual disabilities

IMPORTANCE

Individuals with autism spectrum disorder (ASD) and intellectual disability often experience persistent challenges related to aggressive behaviour and agitation, highlighting the critical need for evidence-based pharmacological interventions among other strategies. Despite previous network meta-analyses (NMAs), the rapidly evolving landscape of treatment options necessitates ongoing and updated assessments.

OBJECTIVE

To evaluate the efficacy and tolerability of various pharmacotherapies in managing agitation in children and adults with ASD or intellectual disabilities (ID).

METHODS

Employing a systematic review and network meta-analysis methodology, we conducted an exhaustive search across multiple databases for double-blind, randomized controlled trials focusing on pharmacotherapies targeting agitation in these neurodevelopmental disorders. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, our assessment of study quality utilized the Cochrane Risk of Bias Tool to ensure methodological rigour and accuracy in data synthesis. Primary outcomes encompassed measures of reduced agitation, as indicated by treatment response on standardized agitation scales, alongside dropout rates, providing a comprehensive overview of treatment efficacy and tolerability.

RESULTS

Our analysis included data from 38 eligible trials, involving 2503 participants across both pediatric and adult populations. Key pharmacological interventions, such as arbaclofen, risperidone plus buspirone, omega-3 fatty acids, risperidone plus palmitoylethanolamide, aripiprazole and risperidone, demonstrated significant efficacy in reducing agitation compared to placebo. Importantly, these treatments were generally well-tolerated, with no significant increase in all-cause dropouts compared to placebo, highlighting their suitability for clinical use in managing agitation in individuals with ASD or ID.

CONCLUSIONS

This study underscores the efficacy and tolerability of several pharmacotherapies in managing agitation among children and adults with ASD or ID. Our findings provide robust evidence that specific treatments, such as arbaclofen, risperidone plus buspirone and omega-3 fatty acids, are both effective and well-tolerated, offering valuable therapeutic options for clinicians. The study emphasizes the need for ongoing research to ensure that treatment strategies remain aligned with the evolving clinical landscape, ultimately improving patient outcomes in this challenging population.

The role of nicotinic acetylcholine receptors in the pathophysiology and pharmacotherapy of autism spectrum disorder: Focus on α7 nicotinic receptors

Postmortem studies have revealed that brains of individuals with autism spectrum disorder (ASD) exhibit abnormalities in various components of the cholinergic system including cholinergic receptors, projections, and nuclei. Deletions in the 15q13.3 region which encompasses CHRNA7, the gene that encodes the α7-nACh receptor, have been linked to various neurodevelopmental disorders, including ASD. In addition, the involvement of α7-nACh receptors in biological phenomena known to play a role in the pathophysiology of ASD such as cognitive functions, learning, memory, neuroinflammation, and oxidative stress, as well as the excitation-inhibition balance in neuronal circuits and maternal immune activation have been reported in previous studies. Furthermore, evolving preclinical and clinical literature supports the potential therapeutic benefits of using selectively acting cholinergic compounds, particularly those targeting the α7-nACh receptor subtype, in the treatment of ASD. This study reviews the previous literature on the involvement of nACh receptors in the pathophysiology of ASD and focuses on the α7-nACh receptor as a potential therapeutic target.

Emerging drugs for the treatment of irritability associated with autism spectrum disorder

INTRODUCTION

Autism spectrum disorder (ASD) is an early-onset disorder with a prevalence of 1% among children and reported disability-adjusted life years of 4.31 million. Irritability is a challenging behavior associated with ASD, for which medication development has lagged. More specifically, pharmacotherapy effectiveness may be limited against high adverse effects (considering side effect profiles and patient medication sensitivity); thus, the possible benefits of pharmacological interventions must be balanced against potential adverse events in each patient.

AREAS COVERED

After reviewing the neuropathophysiology of ASD-associated irritability, the benefits and tolerability of emerging medications in its treatment based on randomized controlled trials were detailed in light of mechanisms and targets of action.

EXPERT OPINION

Succeeding risperidone and aripiprazole, monotherapy with memantine may be beneficial. In addition, N-acetylcysteine, galantamine, sulforaphane, celecoxib, palmitoylethanolamide, pentoxifylline, simvastatin, minocycline, amantadine, pregnenolone, prednisolone, riluzole, propentofylline, pioglitazone, and topiramate, all adjunct to risperidone, and clonidine and methylphenidate outperformed placebo. These effects were through glutamatergic, γ-aminobutyric acidergic, inflammatory, oxidative, cholinergic, dopaminergic, and serotonergic systems. All medications were reported to be safe and tolerable. Considering sample size, follow-up, and effect size, further studies are necessary. Along with drug development, repositioning and combining existing drugs supported by the mechanism of action is recommended.

A machine learning approach for understanding the metabolomics response of children with autism spectrum disorder to medical cannabis treatment

Autism spectrum disorder (ASD) is a neurodevelopmental condition impacting behavior, communication, social interaction and learning abilities. Medical cannabis (MC) treatment can reduce clinical symptoms in individuals with ASD. Cannabis-responsive biomarkers are metabolites found in saliva that change in response to MC treatment. Previously we showed levels of these biomarkers in children with ASD successfully treated with MC shift towards the physiological levels detected in typically developing (TD) children, and potentially can quantify the impact. Here, we tested for the first time the capabilities of machine learning techniques applied to our dynamic, high-resolution and rich feature dataset of cannabis-responsive biomarkers from a limited number of children with ASD before and after MC treatment and a TD group to identify: (1) biomarkers distinguishing ASD and TD groups; (2) non-cannabinoid plant molecules with synergistic effects; and (3) biomarkers associated with specific cannabinoids. We found: (1) lysophosphatidylethanolamine can distinguish between ASD and TD groups; (2) novel phytochemicals contribute to the therapeutic effects of MC treatment by inhibition of acetylcholinesterase; and (3) THC- and CBD-associated cannabis-responsive biomarkers are two distinct groups, while CBG is associated with some biomarkers from both groups.

Basal Forebrain Modulation of Olfactory Coding In Vivo

Sensory perception is one of the most fundamental brain functions, allowing individuals to properly interact and adapt to a constantly changing environment. This process requires the integration of bottom-up and topdown neuronal activity, which is centrally mediated by the basal forebrain, a brain region that has been linked to a series of cognitive processes such as attention and alertness. Here, we review the latest research using optogenetic approaches in rodents and in vivo electrophysiological recordings that are shedding light on the role of this region, in regulating olfactory processing and decisionmaking. Moreover, we summarize evidence highlighting the anatomical and physiological differences in the basal forebrain of individuals with autism spectrum disorder, which could underpin the sensory perception abnormalities they exhibit, and propose this research line as a potential opportunity to understand the neurobiological basis of this disorder.

Acetylcholinesterase inhibitors for autistic spectrum disorders

BACKGROUND

Autism spectrum disorder (autism) is a neurodevelopmental condition characterised by impairments in social communication and interaction, plus restricted, repetitive patterns of behaviour and interests. Whilst some people embrace autism as part of their identity, others struggle with their difficulties, and some seek treatment. There are no current interventions that result in complete reduction of autism features. Acetylcholine is a neurotransmitter for the cholinergic system and has a role in attention, novelty seeking, and memory. Low levels of acetylcholine have been investigated as a potential contributor to autism symptomatology. Donepezil, galantamine, and rivastigmine (commonly referred to as acetylcholinesterase inhibitors) all inhibit acetylcholinesterase, and have slightly different modes of action and biological availability, so their effectiveness and side-effect profiles may vary. The effect of various acetylcholinesterase inhibitor on core autism features across the lifespan, and possible adverse effects, have not been thoroughly investigated.

OBJECTIVES

To evaluate the efficacy and harms of acetylcholinesterase inhibitors for people with the core features (social interaction, communication, and restrictive and repetitive behaviours) of autism. To assess the effects of acetylcholinesterase inhibitors on non-core features of autism.

SEARCH METHODS

In November 2022, we searched CENTRAL, MEDLINE, Embase, eight other databases, and two trials registers. We also searched the reference lists of included studies and relevant reviews, and contacted authors of relevant studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), comparing acetylcholinesterase inhibitors (e.g. galantamine, donepezil, or rivastigmine) of varying doses, delivered orally or via transdermal patch, either as monotherapy or adjunct therapy, with placebo. People of any age, with a clinical diagnosis of autism were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were core features of autism and adverse effects. Secondary outcomes were language, irritability, hyperactivity, and general health and function. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included two RCTs (74 participants). One study was conducted in Iran, the second in the USA, although exact location in the USA is unclear. Galantamine plus risperidone versus placebo plus risperidone One study compared the effects of galantamine plus risperidone to placebo plus risperidone (40 participants, aged 4 years to 12 years). Primary and secondary outcomes of interest were measured postintervention, using subscales of the Aberrant Behavior Checklist (score 0 to 3; higher scores = greater impairment). Very low-certainty evidence showed there was little to no difference between the two groups postintervention for social communication (mean difference (MD) -2.75, 95% confidence interval (CI) -5.88 to 0.38), and restricted and repetitive behaviour (MD -0.55, 95% CI -3.47 to 2.37). Overall autism features were not assessed. Adverse events may be higher in the galantamine plus risperidone group (75%) compared with the placebo plus risperidone group (35%): odds ratio 5.57, 95% CI 1.42 to 21.86, low-certainty evidence. No serious adverse events were reported. Low-certainty evidence showed a small difference in irritability (MD -3.50, 95% CI -6.39 to -0.61), with the galantamine plus risperidone group showing a greater decline on the irritability subscale than the placebo group postintervention. There was no evidence of a difference between the groups in hyperactivity postintervention (MD -5.20, 95% CI -10.51 to 0.11). General health and function were not assessed. Donepezil versus placebo One study compared donepezil to placebo (34 participants aged 8 years to 17 years). Primary outcomes of interest were measured postintervention, using subscales of the Modified Version of The Real Life Rating Scale (scored 0 to 3; higher scores = greater impairment). Very low-certainty evidence showed no evidence of group differences immediately postintervention in overall autism features (MD 0.07, 95% CI -0.19 to 0.33), or in the autism symptom domains of social communication (MD -0.02, 95% CI -0.34 to 0.30), and restricted and repetitive behaviours (MD 0.04, 95% CI -0.27 to 0.35). Significant adverse events leading to study withdrawal in at least one participant was implied in the data analysis section, but not explicitly reported. The evidence is very uncertain about the effect of donepezil, compared to placebo, on the secondary outcomes of interest, including irritability (MD 1.08, 95% CI -0.41 to 2.57), hyperactivity (MD 2.60, 95% CI 0.50 to 4.70), and general health and function (MD 0.03, 95% CI -0.48 to 0.54) postintervention. Across all analyses within this comparison, we judged the evidence to be very low-certainty due to high risk of bias, and very serious imprecision (results based on one small study with wide confidence intervals). The study narratively reported adverse events for the study as a whole, rather than by treatment group.

AUTHORS' CONCLUSIONS

Evidence about the effectiveness of acetylcholinesterase inhibitors as a medication to improve outcomes for autistic adults is lacking, and for autistic children is very uncertain. There is a need for more evidence of improvement in outcomes of relevance to clinical care, autistic people, and their families. There are a number of ongoing studies involving acetylcholinesterase inhibitors, and future updates of this review may add to the current evidence.

Maternal Inflammation with Elevated Kynurenine Metabolites Is Related to the Risk of Abnormal Brain Development and Behavioral Changes in Autism Spectrum Disorder

Several studies show that genetic and environmental factors contribute to the onset and progression of neurodevelopmental disorders. Maternal immune activation (MIA) during gestation is considered one of the major environmental factors driving this process. The kynurenine pathway (KP) is a major route of the essential amino acid L-tryptophan (Trp) catabolism in mammalian cells. Activation of the KP following neuro-inflammation can generate various endogenous neuroactive metabolites that may impact brain functions and behaviors. Additionally, neurotoxic metabolites and excitotoxicity cause long-term changes in the trophic support, glutamatergic system, and synaptic function following KP activation. Therefore, investigating the role of KP metabolites during neurodevelopment will likely promote further understanding of additional pathophysiology of neurodevelopmental disorders, including autism spectrum disorder (ASD). In this review, we describe the changes in KP metabolism in the brain during pregnancy and represent how maternal inflammation and genetic factors influence the KP during development. We overview the patients with ASD clinical data and animal models designed to verify the role of perinatal KP elevation in long-lasting biochemical, neuropathological, and behavioral deficits later in life. Our review will help shed light on new therapeutic strategies and interventions targeting the KP for neurodevelopmental disorders.

Systematic Review and Meta-analysis: Pharmacological and Nonpharmacological Interventions for Persistent Nonepisodic Irritability

OBJECTIVE

This meta-analysis examined the efficacy of available pharmacological and nonpharmacological interventions for irritability among youth with autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), disruptive behavior disorders (DBD), disruptive mood dysregulation disorder (DMDD), and/or severe mood dysregulation (SMD).

METHOD

Literature searches were conducted in October 2020, resulting in 564 abstracts being reviewed to identify relevant papers, with 387 articles being reviewed in full. A random effects model was used for the meta-analysis, with subgroup meta-regressions run to assess effects of study design, intervention type, medication class, and clinical population.

RESULTS

A total of 101 studies were included (80 pharmacological, 13 nonpharmacological, 8 combined). Despite high heterogeneity in effects (I2 = 94.3%), pooled posttreatment effect size for decreasing irritability was large (Hedges' g = 1.62). Large effects were found for pharmacological (g = 1.85) and nonpharmacological (g = 1.11) interventions; moderate effects were found for combined interventions relative to monotherapy interventions (g = 0.69). Antipsychotic medications provided the largest effect for reducing irritability relative to all other medication classes and nonpharmacological interventions. A large effect was found for youth with ASD (g = 1.89), whereas a medium effect was found for youth with ADHD/DMDD/DBD/SMD (g = 0.64).

CONCLUSION

This meta-analysis provides a comprehensive review of interventions targeting persistent nonepisodic irritability among youth with various psychiatric disorders. Strong evidence was found for medium-to-large effects across study design, intervention type, and clinical populations, with the largest effects for pharmacological interventions, particularly antipsychotic medications and combined pharmacological interventions, and interventions for youth with ASD.

Catecholaminergic and cholinergic neuromodulation in autism spectrum disorder: A comparison to attention-deficit hyperactivity disorder

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by social impairments and restricted, repetitive behaviors. Treatment of ASD is notoriously difficult and might benefit from identification of underlying mechanisms that overlap with those disturbed in other developmental disorders, for which treatment options are more obvious. One example of the latter is attention-deficit hyperactivity disorder (ADHD), given the efficacy of especially stimulants in treatment of ADHD. Deficiencies in catecholaminergic systems [dopamine (DA), norepinephrine (NE)] in ADHD are obvious targets for stimulant treatment. Recent findings suggest that dysfunction in catecholaminergic systems may also be a factor in at least a subgroup of ASD. In this review we scrutinize the evidence for catecholaminergic mechanisms underlying ASD symptoms, and also include in this analysis a third classic ascending arousing system, the acetylcholinergic (ACh) network. We complement this with a comprehensive review of DA-, NE-, and ACh-targeted interventions in ASD, and an exploratory search for potential treatment-response predictors (biomarkers) in ASD, genetically or otherwise. Based on this review and analysis we propose that (1) stimulant treatment may be a viable option for an ASD subcategory, possibly defined by genetic subtyping; (2) cerebellar dysfunction is pronounced for a relatively small ADHD subgroup but much more common in ASD and in both cases may point toward NE- or ACh-directed intervention; (3) deficiency of the cortical salience network is sizable in subgroups of both disorders, and biomarkers such as eye blink rate and pupillometric data may predict the efficacy of targeting this underlying deficiency via DA, NE, or ACh in both ASD and ADHD.

Galantamine beyond Alzheimer's disease-a fact or artefact?

Galantamine is US-Food and Drug Administration FDA-approved for mild-to-moderate Alzheimer's disease. However, its unique pharmacological portfolio speaks to the idea of a pluripotent agent with a broad therapeutic potential. Here, authors briefly discuss these off-label clinical indications synthesizing the extant evidence.

Exploring the vagus nerve and the inflammatory reflex for therapeutic benefit in chronic spinal cord injury

PURPOSE OF REVIEW

To describe features and implications of chronic systemic inflammation in individuals with spinal cord injury (SCI) and to summarize the growing therapeutic possibilities to explore the vagus nerve-mediated inflammatory reflex in this context.

RECENT FINDINGS

The discovery of the inflammatory reflex provides a rationale to explore neuromodulation modalities, that is, electrical vagus nerve stimulation and pharmacological cholinergic modalities to regulate inflammation after SCI.

SUMMARY

Inflammation in individuals with SCI may negatively impact functional recovery and medical consequences after SCI. Exploring the potential of the vagus nerve-based inflammatory reflex to restore autonomic regulation and control inflammation may provide a novel approach for functional improvement in SCI.

Dysregulation of Neuronal Nicotinic Acetylcholine Receptor-Cholesterol Crosstalk in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a set of complex neurodevelopmental diseases that include impaired social interaction, delayed and disordered language, repetitive or stereotypic behavior, restricted range of interests, and altered sensory processing. The underlying causes of the core symptoms remain unclear, as are the factors that trigger their onset. Given the complexity and heterogeneity of the clinical phenotypes, a constellation of genetic, epigenetic, environmental, and immunological factors may be involved. The lack of appropriate biomarkers for the evaluation of neurodevelopmental disorders makes it difficult to assess the contribution of early alterations in neurochemical processes and neuroanatomical and neurodevelopmental factors to ASD. Abnormalities in the cholinergic system in various regions of the brain and cerebellum are observed in ASD, and recently altered cholesterol metabolism has been implicated at the initial stages of the disease. Given the multiple effects of the neutral lipid cholesterol on the paradigm rapid ligand-gated ion channel, the nicotinic acetylcholine receptor, we explore in this review the possibility that the dysregulation of nicotinic receptor-cholesterol crosstalk plays a role in some of the neurological alterations observed in ASD.

Treating disorders across the lifespan by modulating cholinergic signaling with galantamine

Advances in understanding the regulatory functions of the nervous system have revealed neural cholinergic signaling as a key regulator of cytokine responses and inflammation. Cholinergic drugs, including the centrally acting acetylcholinesterase inhibitor, galantamine, which are in clinical use for the treatment of Alzheimer's disease and other neurodegenerative and neuropsychiatric disorders, have been rediscovered as anti-inflammatory agents. Here, we provide a timely update on this active research and clinical developments. We summarize the involvement of cholinergic mechanisms and inflammation in the pathobiology of Alzheimer's disease, Parkinson's disease, and schizophrenia, and the effectiveness of galantamine treatment. We also highlight recent findings demonstrating the effects of galantamine in preclinical and clinical settings of numerous conditions and diseases across the lifespan that are characterized by immunological, neurological, and metabolic dysfunction.

From Research to Practice: Toward the Examination of Combined Interventions for Autism Spectrum Disorders

The use of biological (i.e., medications) in conjunction with applied behavior analysis is relatively common among people with ASD, yet research examining its benefit is scarce. This paper provides a brief overview of the existing literature on the combined interventions, including promising developments, and examines the existing barriers that hinder research in this area, including the heavy reliance on RCTs. Recommendations for possible solutions, including the creation of health homes, are provided in order to move toward a more integrated approach.

Curcumin Potentiates α7 Nicotinic Acetylcholine Receptors and Alleviates Autistic-Like Social Deficits and Brain Oxidative Stress Status in Mice

Autistic spectrum disorder (ASD) refers to a group of neurodevelopmental disorders characterized by impaired social interaction and cognitive deficit, restricted repetitive behaviors, altered immune responses, and imbalanced oxidative stress status. In recent years, there has been a growing interest in studying the role of nicotinic acetylcholine receptors (nAChRs), specifically α7-nAChRs, in the CNS. Influence of agonists for α7-nAChRs on the cognitive behavior, learning, and memory formation has been demonstrated in neuro-pathological condition such as ASD and attention-deficit hyperactivity disorder (ADHD). Curcumin (CUR), the active compound of the spice turmeric, has been shown to act as a positive allosteric modulator of α7-nAChRs. Here we hypothesize that CUR, acting through α7-nAChRs, influences the neuropathology of ASD. In patch clamp studies, fast inward currents activated by choline, a selective agonist of α7-nAChRs, were significantly potentiated by CUR. Moreover, choline induced enhancement of spontaneous inhibitory postsynaptic currents was markedly increased in the presence of CUR. Furthermore, CUR (25, 50, and 100 mg/kg, i.p.) ameliorated dose-dependent social deficits without affecting locomotor activity or anxiety-like behaviors of tested male Black and Tan BRachyury (BTBR) mice. In addition, CUR (50 and 100 mg/kg, i.p.) mitigated oxidative stress status by restoring the decreased levels of superoxide dismutase (SOD) and catalase (CAT) in the hippocampus and the cerebellum of treated mice. Collectively, the observed results indicate that CUR potentiates α7-nAChRs in native central nervous system neurons, mitigates disturbed oxidative stress, and alleviates ASD-like features in BTBR mice used as an idiopathic rodent model of ASD, and may represent a promising novel pharmacological strategy for ASD treatment.

The evolving obesity challenge: targeting the vagus nerve and the inflammatory reflex in the response

Obesity and the metabolic syndrome (MetS), which have reached pandemic proportions significantly increase the risk for type 2 diabetes, cardiovascular disease, and other serious conditions. Recent data with COVID-19 patients indicate that obesity also is a significant risk factor for this novel viral disease and poor outcome of associated critical illness. These findings considerably change the view of obesity as a driver of serious, but slowly-progressing chronic diseases, and emphasize the urgency to explore new therapeutic approaches. Inflammation is a recognized driver of metabolic derangements in obesity and MetS, and a core feature of COVID-19 pathobiology. Recent advances in our understanding of inflammatory regulation have highlighted the role of the nervous system and the vagus nerve-based inflammatory reflex. Current bioelectronic and pharmacological therapeutic explorations centered on the inflammatory reflex offer new approaches for conditions characterized by immune and metabolic dysregulation and for ameliorating the escalating burden of obesity, MetS, and COVID-19.

In silico Gene Set and Pathway Enrichment Analyses Highlight Involvement of Ion Transport in Cholinergic Pathways in Autism: Rationale for Nutritional Intervention

Food is the primary human source of choline, an essential precursor to the neurotransmitter acetylcholine, which has a central role in signaling pathways that govern sensorimotor functions. Most Americans do not consume their recommended amount of dietary choline, and populations with neurodevelopmental conditions like autism spectrum disorder (ASD) may be particularly vulnerable to consequences of choline deficiency. This study aimed to identify a relationship between ASD and cholinergic signaling through gene set enrichment analysis and interrogation of existing database evidence to produce a systems biology model. In gene set enrichment analysis, two gene ontologies were identified as overlapping for autism-related and for cholinergic pathways-related functions, both involving ion transport regulation. Subsequent modeling of ion transport intensive cholinergic signaling pathways highlighted the importance of two genes with autism-associated variants: GABBR1, which codes for the gamma aminobutyric acid receptor (GABAB 1), and KCNN2, which codes for calcium-activated, potassium ion transporting SK2 channels responsible for membrane repolarization after cholinergic binding/signal transmission events. Cholinergic signal transmission pathways related to these proteins were examined in the Pathway Studio environment. The ion transport ontological associations indicated feasibility of a dietary choline support as a low-risk therapeutic intervention capable of modulating cholinergic sensory signaling in autism. Further research at the intersection of dietary status and sensory function in autism is warranted.

Impact of antipsychotics in children and adolescents with autism spectrum disorder: a systematic review and meta-analysis

Background

The net health benefit of using antipsychotics in children and adolescents with ASD is unclear. This review was performed to provide the evidence necessary to inform the Italian national guidelines for the management of ASD.

Methods

We performed a systematic review of randomized controlled trials (RCTs) comparing antipsychotics versus placebo for the treatment of ASD in children and adolescents. For efficacy, acceptability and safety we considered outcomes evaluated by the guideline panel critical and important for decision-making. Continuous outcomes were analyzed by using standardized mean difference (SMD), and dichotomous outcomes by calculating the risk ratio (RR), with their 95% confidence interval (95% CI). Data were analyzed using a random effects model. We used the Cochrane tool to assess risk of bias of included studies. Certainty in the evidence of effects was assessed according to the GRADE approach.

Results

We included 21 RCTs with 1,309 participants, comparing antipsychotics to placebo. Antipsychotics were found effective on “restricted and repetitive interests and behaviors” (SMD − 0.21, 95% CI − 0.35 to − 0.07, moderate certainty), “hyperactivity, inattention, oppositional, disruptive behavior” (SMD − 0.67, 95% CI − 0.92 to − 0.42, moderate certainty), “social communication, social interaction” (SMD − 0.38, 95% CI − 0.59 to − 0.16, moderate certainty), “emotional dysregulation/irritability” (SMD − 0.71, 95% CI − 0.98 to − 0.43, low certainty), “global functioning, global improvement” (SMD − 0.64, 95% CI − 0.96 to − 0.33, low certainty), “obsessions, compulsions” (SMD − 0.30, 95% CI − 0.55 to − 0.06, moderate certainty). Antipsychotics were not effective on “self-harm” (SMD − 0.14, 95% CI − 0.58 to 0.30, very low certainty), “anxiety” (SMD − 0.38, 95% CI − 0.82 to 0.07, very low certainty). Antipsychotics were more acceptable in terms of dropout due to any cause (RR 0.61, 95% CI 0.48 to 0.78, moderate certainty), but were less safe in terms of patients experiencing adverse events (RR 1.19, 95% CI 1.07 to 1.32, moderate certainty), and serious adverse events (RR 1.07, 95% CI 0.48 to 2.43, low certainty).

Conclusions

Our systematic review and meta-analysis found antipsychotics for children and adolescents with ASD more efficacious than placebo in reducing stereotypies, hyperactivity, irritability and obsessions, compulsions, and in increasing social communication and global functioning. Antipsychotics were also found to be more acceptable, but less safe than placebo.

Sulforaphane as an adjunctive treatment for irritability in children with autism spectrum disorder: A randomized, double-blind, placebo-controlled clinical trial

AIM

Irritability related to autism spectrum disorder (ASD) complicates the management of ASD patients at home and in clinical settings. In this randomized, double-blind, placebo-controlled clinical trial, we aimed to investigate the beneficial effects of adjuvant treatment with risperidone and sulforaphane in alleviating the irritability of children with ASD.

METHODS

Sixty drug-free patients aged 4-12 years were randomly assigned to one of two groups receiving risperidone plus sulforaphane or placebo. Risperidone was started with a daily dose of 0.25 mg in patients weighing <20 kg and 0.5 mg in those weighing ≥20 kg and increased stepwise to reach a maximum of 1 mg (<20 kg), 2.5 mg (20-45 kg), and 3.5 mg (>45 kg). Sulforaphane was administered at a daily dose of 50 μmol (≤45 kg) or 100 μmol (>45 kg). The participants were assessed with the Aberrant Behavior Checklist - Community Edition at baseline and at Weeks 5 and 10.

RESULTS

Compared to the placebo group, ASD patients in the sulforaphane group showed greater improvements in Irritability score (primary outcome measure; P = 0.001) and Hyperactivity/Noncompliance score (secondary outcome measure; P = 0.015), and significant Time × Treatment effect for Irritability (P = 0.007) and Hyperactivity/Noncompliance (P = 0.008). However, no difference was seen in improvements in the other secondary measures: Lethargy/Social Interaction score, Stereotypic Behavior score, Inappropriate Speech score, and frequency of adverse events.

CONCLUSION

Our results support the safety and efficacy of sulforaphane as an adjuvant to risperidone for improvement of irritability and hyperactivity symptoms in children with ASD.

Role of Neuroinflammation in Autism Spectrum Disorder and the Emergence of Brain Histaminergic System. Lessons Also for BPSD?

Many behavioral and psychological symptoms of dementia (BPSD) share similarities in executive functioning and communication deficits with those described in several neuropsychiatric disorders, including Alzheimer's disease (AD), epilepsy, schizophrenia (SCH), and autism spectrum disorder (ASD). Numerous studies over the last four decades have documented altered neuroinflammation among individuals diagnosed with ASD. The purpose of this review is to examine the hypothesis that central histamine (HA) plays a significant role in the regulation of neuroinflammatory processes of microglia functions in numerous neuropsychiatric diseases, i.e., ASD, AD, SCH, and BPSD. In addition, this review summarizes the latest preclinical and clinical results that support the relevance of histamine H1-, H2-, and H3-receptor antagonists for the potential clinical use in ASD, SCH, AD, epilepsy, and BPSD, based on the substantial symptomatic overlap between these disorders with regards to cognitive dysfunction. The review focuses on the histaminergic neurotransmission as relevant in these brain disorders, as well as the effects of a variety of H3R antagonists in animal models and in clinical studies.

The Neurochemistry of Autism

Autism spectrum disorder (ASD) refers to complex neurobehavioral and neurodevelopmental conditions characterized by impaired social interaction and communication, restricted and repetitive patterns of behavior or interests, and altered sensory processing. Environmental, immunological, genetic, and epigenetic factors are implicated in the pathophysiology of autism and provoke the occurrence of neuroanatomical and neurochemical events relatively early in the development of the central nervous system. Many neurochemical pathways are involved in determining ASD; however, how these complex networks interact and cause the onset of the core symptoms of autism remains unclear. Further studies on neurochemical alterations in autism are necessary to clarify the early neurodevelopmental variations behind the enormous heterogeneity of autism spectrum disorder, and therefore lead to new approaches for the treatment and prevention of autism. In this review, we aim to delineate the state-of-the-art main research findings about the neurochemical alterations in autism etiology, and focuses on gamma aminobutyric acid (GABA) and glutamate, serotonin, dopamine, N-acetyl aspartate, oxytocin and arginine-vasopressin, melatonin, vitamin D, orexin, endogenous opioids, and acetylcholine. We also aim to suggest a possible related therapeutic approach that could improve the quality of ASD interventions. Over one hundred references were collected through electronic database searching in Medline and EMBASE (Ovid), Scopus (Elsevier), ERIC (Proquest), PubMed, and the Web of Science (ISI).

An Evolving Therapeutic Rationale for Targeting the α7 Nicotinic Acetylcholine Receptor in Autism Spectrum Disorder

Abnormalities of cholinergic nuclei, cholinergic projections, and cholinergic receptors, as well as abnormalities of growth factors involved in the maturation and maintenance of cholinergic neurons, have been described in postmortem brains of persons with autism spectrum disorder (ASD). Further, microdeletions of the 15q13.3 locus that encompasses CHRNA7, the gene coding the α₇ nicotinic acetylcholine receptor (α₇ nAChR), are associated with a spectrum of neurodevelopmental disorders, including ASD. The heterozygous 15q13.3 microdeletion syndrome suggests that diminished or impaired transduction of the acetylcholine (ACh) signal by the α₇ nAChR can be a pathogenic mechanism of ASD. The α₇ nAChR has a role in regulating the firing and function of parvalbumin (PV)-expressing GABAergic projections, which synchronize the oscillatory output of assemblies of pyramidal neurons onto which they project. Synchronous oscillatory output is an electrophysiological substrate for higher executive functions, such as working memory, and functional connectivity between discrete anatomic areas of the brain. The α₇ nAChR regulates PV expression and works cooperatively with the co-expressed NMDA receptor in subpopulations of GABAergic interneurons in mouse models of ASD. An evolving literature supports therapeutic exploration of selectively targeted cholinergic interventions for the treatment of ASD, especially compounds that target the α₇ nAChR subtype. Importantly, development and availability of high-affinity, brain-penetrable, α₇ nAChR-selective agonists, partial agonists, allosteric agonists, and positive allosteric modulators (PAMs) should facilitate "proof-of-principle/concept" clinical trials. nAChRs are pentameric allosteric proteins that function as ligand-gated ion channel receptors constructed from five constituent polypeptide subunits, all of which share a common structural motif. Importantly, in addition to α₇ nAChR-gated Ca²⁺ conductance causing membrane depolarization, there are emerging data consistent with possible metabotropic functions of this ionotropic receptor. The ability of α₇-selective type II PAMs to "destabilize" the desensitized state and promote ion channel opening may afford them therapeutic advantages over orthosteric agonists. The current chapter reviews historic and recent literature supporting selective therapeutic targeting of the α₇ nAChR in persons affected with ASD.

Review of Clinical Studies Targeting Inflammatory Pathways for Individuals With Autism

Immune dysfunction and abnormal immune response may be associated with certain mechanisms underlying autism spectrum disorder (ASD). The early evidence for this link was based on the increased incidence of ASD in children with a history of maternal infection during pregnancy. Observational studies show increased prevalence of immune-related disorders-ranging from atopy, food allergy, viral infections, asthma, primary immunodeficiency, to autoimmune disorders-in individuals with ASD and their families. Evidence of neuroglial activation and focal brain inflammation in individuals with ASD implies that the central nervous system immunity may also be atypical in some individuals with ASD. Also, both peripheral and central inflammatory responses are suggested to be associated with ASD-related behavioral symptoms. Atypical immune responses may be evident in specific ASD subgroups, such as those with significant gastrointestinal symptoms. The present review aimed to evaluate current literature of potential interventions that target inflammatory pathways for individuals with ASD and to summarize whether these interventions were associated with improvement in autism symptoms and adaptation. We found that the current literature on the efficacy of anti-inflammatory interventions in ASD is still limited and large-scale randomized controlled trials are needed to provide robust evidence. We concluded that the role of immune-mediated mechanisms in the emergence of ASD or related challenges may be specific to subsets of individuals (e.g. those with concurrent immunological disorders, developmental regression, or high irritability). These subsets of individuals of ASD might be more likely to benefit from interventions that target immune-mediated mechanisms and with whom next-stage immune-mediated clinical trials could be conducted.

Systematic review and guide to management of core and psychiatric symptoms in youth with autism

OBJECTIVE

Evidence-based guidance of clinical decision-making for the management of Autism Spectrum Disorder (ASD) is lacking, particularly for co-occurring psychiatric symptoms. This review evaluates treatment evidence for six common symptom targets in children/adolescents with ASD and provides a resource to facilitate application of the evidence to clinical practice.

METHOD

A systematic search identified randomized controlled trials (RCTs) and high-quality systematic reviews published between 2007 and 2016, focused on: social interaction/communication impairment, stereotypic/repetitive behaviours, irritability/agitation, attention-deficit/hyperactivity disorder symptoms, mood or anxiety symptoms, and sleep difficulties. We then completed qualitative evaluation of high-quality systematic reviews/meta-analyses and quantitative evaluation of recently published RCTs not covered by prior comprehensive systematic reviews.

RESULTS

Recently published RCTs focused on social interaction and communication impairment (trials = 32) using psychosocial interventions. Interventions for irritability/agitation (trials = 16) were mainly pharmacological. Few RCTs focused on other symptom targets (trials = 2-5/target). Integration of these results with our qualitative review indicated that few established treatment modalities exist, and available evidence is limited by small studies with high risk of bias.

CONCLUSION

Given the current evidence-base, treatment targets must be clearly defined, and a systematic approach to intervention trials in children/adolescents with ASD must be undertaken with careful consideration of the limitations of safety/efficacy data.

Palmitoylethanolamide as adjunctive therapy for autism: Efficacy and safety results from a randomized controlled trial

Inflammation as well as glutamate excitotoxicity have been proposed to participate in the propagation of autism. Palmitoylethanolamide (PEA) is an endocannabinoid proven to prevent glutamatergic toxicity and inhibit inflammatory responses simultaneously. The present randomized, parallel group, double-blind placebo-controlled trial is the first study depicted to probe the efficacy of co-treatment with risperidone and PEA over 10 weeks in children with autism. Seventy children (aged 4-12 years) with autism and moderate to severe symptoms of irritability were randomly assigned to two treatment regimens. The study outcomes were measured using the Aberrant Behavior Checklist-Community Edition (ABC-C). At trial endpoint (week 10), combination of PEA and risperidone had superior efficacy in ameliorating the ABC-irritability and hyperactivity/noncompliance symptoms (Cohen's d, 95% confidence interval (CI) = 0.94, 0.41 to 1.46, p = 0.001) compared with a risperidone plus placebo regimen. Interestingly, effect of combination treatment on hyperactivity symptoms was also observed at trial midpoint (week 5) but with a smaller effect size (d = 0.53, p = 0.04) than that at the endpoint (d = 0.94, p = 0.001). Meanwhile, there was a trend toward significance for superior effect of risperidone plus PEA over risperidone plus placebo on inappropriate speech at trial endpoint (d = 0.51, p = 0.051). No significant differences existed between the two treatment groups for the other two ABC-C subscales (lethargy/social withdrawal and stereotypic behavior). The findings suggest that PEA may augment therapeutic effects of risperidone on autism-related irritability and hyperactivity. Future studies are warranted to investigate whether PEA can serve as a stand-alone treatment for autism.

Autism throughout genetics: Perusal of the implication of ion channels

BACKGROUND

Autism spectrum disorder (ASD) comprises a group of neurodevelopmental psychiatric disorders characterized by deficits in social interactions, interpersonal communication, repetitive and stereotyped behaviors and may be associated with intellectual disabilities. The description of ASD as a synaptopathology highlights the importance of the synapse and the implication of ion channels in the etiology of these disorders.

METHODS

A narrative and critical review of the relevant papers from 1982 to 2017 known by the authors was conducted.

RESULTS

Genome-wide linkages, association studies, and genetic analyses of patients with ASD have led to the identification of several candidate genes and mutations linked to ASD. Many of the candidate genes encode for proteins involved in neuronal development and regulation of synaptic function including ion channels and actors implicated in synapse formation. The involvement of ion channels in ASD is of great interest as they represent attractive therapeutic targets. In agreement with this view, recent findings have shown that drugs modulating ion channel function are effective for the treatment of certain types of patients with ASD.

CONCLUSION

This review describes the genetic aspects of ASD with a focus on genes encoding ion channels and highlights the therapeutic implications of ion channels in the treatment of ASD.

l-Carnosine As an Adjunctive Therapy to Risperidone in Children with Autistic Disorder: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVES

This study aimed at investigating the efficacy and tolerability of l-carnosine as an add-on to risperidone in the management of children with autism.

METHODS

This was a 10-week, randomized, double-blind, placebo-controlled study. Seventy drug-free children aged 4-12 years old with a diagnosis of autism spectrum disorder (ASD), according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition. (DSM-5) who had an Aberrant Behavior Checklist-Community (ABC-C) scale irritability subscale score of ≥12, entered the study. The patients were randomly assigned to l-carnosine (800 mg/day in 2 divided doses) or placebo in addition to risperidone titrated up to 2 mg/day (based on body weight) for 10 weeks. The children were assessed by using ABC-C at baseline and weeks 5 and 10 post-baseline. The primary outcome measure was the mean change in the ABC-C irritability subscale score, and other subscale scores were defined as secondary outcomes.

RESULTS

Using the general linear model repeated measures, no significant effect was observed for time × treatment interaction on the irritability subscale scores. However, significant effect was detected on the hyperactivity/noncompliance subscale [F (1.62, 64.96) = 3.53, p-value = 0.044]. No significant improvements were obtained on the lethargy/social withdrawal, stereotypic behavior, and inappropriate speech subscale scores. Significantly greater score reduction in the hyperactivity/noncompliance subscale occurred in the l-carnosine group compared with the placebo group at the end of the trial. Extrapyramidal Symptom Rating Scale Scores and its changes did not differ between the two groups. The frequency of other side effects was not significantly different between the two groups.

CONCLUSIONS

Although no significant difference was detected on the irritability subscale scores, l-carnosine add-on can improve hyperactivity/noncompliance subscales of the ABC-C rating scale in patients with ASD.

Galantamine alleviates inflammation and insulin resistance in patients with metabolic syndrome in a randomized trial

BACKGROUND

Metabolic syndrome (MetS) is an obesity-driven condition of pandemic proportions that increases the risk of type 2 diabetes and cardiovascular disease. Pathophysiological mechanisms are poorly understood, though inflammation has been implicated in MetS pathogenesis. The aim of this study was to assess the effects of galantamine, a centrally acting acetylcholinesterase inhibitor with antiinflammatory properties, on markers of inflammation implicated in insulin resistance and cardiovascular risk, and other metabolic and cardiovascular indices in subjects with MetS.

METHODS

In this randomized, double-blind, placebo-controlled trial, subjects with MetS (30 per group) received oral galantamine 8 mg daily for 4 weeks, followed by 16 mg daily for 8 weeks or placebo. The primary outcome was inflammation assessed through plasma levels of cytokines and adipokines associated with MetS. Secondary endpoints included body weight, fat tissue depots, plasma glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), cholesterol (total, HDL, LDL), triglycerides, BP, heart rate, and heart rate variability (HRV).

RESULTS

Galantamine resulted in lower plasma levels of proinflammatory molecules TNF (-2.57 pg/ml [95% CI -4.96 to -0.19]; P = 0.035) and leptin (-12.02 ng/ml [95% CI -17.71 to -6.33]; P < 0.0001), and higher levels of the antiinflammatory molecules adiponectin (2.71 μg/ml [95% CI 1.93 to 3.49]; P < 0.0001) and IL-10 (1.32 pg/ml, [95% CI 0.29 to 2.38]; P = 0.002) as compared with placebo. Galantamine also significantly lowered plasma insulin and HOMA-IR values, and altered HRV.

CONCLUSION

Low-dose galantamine alleviates inflammation and insulin resistance in MetS subjects. These findings support further study of galantamine in MetS therapy.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT02283242.

FUNDING

Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil, and the NIH.

Minocycline as Adjunctive Treatment to Risperidone in Children with Autistic Disorder: A Randomized, Double-Blind Placebo-Controlled Trial

OBJECTIVE

This is an investigation of minocycline efficacy and safety as an adjuvant to risperidone in management of children with autism.

METHODS

Forty-six children with diagnosis of autistic disorder, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR) criteria and a score of ≥12 on the Aberrant Behavior Checklist-Community (ABC-C) irritability subscale, who were already drug-free for at least 6 months participated in a randomized controlled trial and underwent 10 weeks of treatment with either minocycline (50 mg twice per day) or placebo in addition to risperidone titrated up to 2 mg/day (based on bodyweight). Patients were evaluated using ABC-C at baseline and at weeks 5 and 10.

RESULTS

General linear model repeated measures showed significant effect for time × treatment interaction on the irritability [F(2, 88) = 3.94, p = 0.02] and hyperactivity/noncompliance [F(1.50, 66.05) = 7.92, p = 0.002], but not for lethargy/social withdrawal [F(1.61, 71.02) = 0.98, p = 0.36], stereotypic behavior [F(1.34, 58.80) = 1.55, p = 0.22], and inappropriate speech subscale scores [F(1.52, 66.88) = 1.15, p = 0.31]. By week 10, 21 (91.3%) patients in the minocycline group and 15 (65.5%) patients in the placebo group achieved at least partial response (p = 0.03). Frequencies of adverse events were not significantly different between groups.

CONCLUSIONS

Minocycline seems to be a safe and effective adjuvant in management of patients with autistic disorder. Future studies with larger sample sizes, longer follow-ups, and inflammatory cytokine measurements are warranted to confirm these findings and provide insight into minocycline mechanism of action in autistic disorder.

Postsynaptic nicotinic acetylcholine receptors facilitate excitation of developing CA1 pyramidal neurons

The hippocampus plays a key role in learning and memory. The normal development and mature function of hippocampal networks supporting these cognitive functions depends on afferent cholinergic neurotransmission mediated by nicotinic acetylcholine receptors. Whereas it is well-established that nicotinic receptors are present on GABAergic interneurons and on glutamatergic presynaptic terminals within the hippocampus, the ability of these receptors to mediate postsynaptic signaling in pyramidal neurons is not well understood. We use whole cell electrophysiology to show that heteromeric nicotinic receptors mediate direct inward currents, depolarization from rest and enhanced excitability in hippocampus CA1 pyramidal neurons of male mice. Measurements made throughout postnatal development provide a thorough developmental profile for these heteromeric nicotinic responses, which are greatest during the first 2 wk of postnatal life and decrease to low adult levels shortly thereafter. Pharmacological experiments show that responses are blocked by a competitive antagonist of α4β2* nicotinic receptors and augmented by a positive allosteric modulator of α5 subunit-containing receptors, which is consistent with expression studies suggesting the presence of α4β2 and α4β2α5 nicotinic receptors within the developing CA1 pyramidal cell layer. These findings demonstrate that functional heteromeric nicotinic receptors are present on CA1 pyramidal neurons during a period of major hippocampal development, placing these receptors in a prime position to play an important role in the establishment of hippocampal cognitive networks.

Modulatory effects of α7 nAChRs on the immune system and its relevance for CNS disorders

The clinical development of selective alpha-7 nicotinic acetylcholine receptor (α7 nAChR) agonists has hitherto been focused on disorders characterized by cognitive deficits (e.g., Alzheimer's disease, schizophrenia). However, α7 nAChRs are also widely expressed by cells of the immune system and by cells with a secondary role in pathogen defense. Activation of α7 nAChRs leads to an anti-inflammatory effect. Since sterile inflammation is a frequently observed phenomenon in both psychiatric disorders (e.g., schizophrenia, melancholic and bipolar depression) and neurological disorders (e.g., Alzheimer's disease, Parkinson's disease, and multiple sclerosis), α7 nAChR agonists might show beneficial effects in these central nervous system disorders. In the current review, we summarize information on receptor expression, the intracellular signaling pathways they modulate and reasons for receptor dysfunction. Information from tobacco smoking, vagus nerve stimulation, and cholinesterase inhibition is used to evaluate the therapeutic potential of selective α7 nAChR agonists in these inflammation-related disorders.

Modulation of social deficits and repetitive behaviors in a mouse model of autism: the role of the nicotinic cholinergic system

RATIONALE

Accumulating evidence implicates the nicotinic cholinergic system in autism spectrum disorder (ASD) pathobiology. Neuropathologic studies suggest that nicotinic acetylcholine (ACh) receptor (nAChR) subtypes are altered in brain of autistic individuals. In addition, strategies that increase ACh, the neurotransmitter for nicotinic and muscarinic receptors, appear to improve cognitive deficits in neuropsychiatric disorders and ASD.

OBJECTIVE

The aim of this study is to examine the role of the nicotinic cholinergic system on social and repetitive behavior abnormalities and exploratory physical activity in a well-studied model of autism, the BTBR T(+) Itpr3 (tf) /J (BTBR) mouse.

METHODS

Using a protocol known to up-regulate expression of brain nAChR subtypes, we measured behavior outcomes before and after BTBR and C57BL/6J (B6) mice were treated (4 weeks) with vehicle or nicotine (50, 100, 200, or 400 μg/ml).

RESULTS

Increasing nicotine doses were associated with decreases in water intake, increases in plasma cotinine levels, and at the higher dose (400 μg/ml) with weight loss in BTBR mice. At lower (50, 100 μg/ml) but not higher (200, 400 μg/ml) doses, nicotine increased social interactions in BTBR and B6 mice and at higher, but not lower doses, it decreased repetitive behavior in BTBR. In the open-field test, nicotine at 200 and 400 μg/ml, but not 100 μg/ml compared with vehicle, decreased overall physical activity in BTBR mice.

CONCLUSIONS

These findings support the hypotheses that the nicotinic cholinergic system modulates social and repetitive behaviors and may be a therapeutic target to treat behavior deficits in ASD. Further, the BTBR mouse may be valuable for investigations of the role of nAChRs in social deficits and repetitive behavior.

A pilot double-blind placebo-controlled trial of pioglitazone as adjunctive treatment to risperidone: Effects on aberrant behavior in children with autism

To assess the safety and efficacy of pioglitazone added to risperidone in the treatment of irritability in autistic disorder (AD), we conducted this study. In a 10-week, randomized, double-blind, parallel-group, placebo-controlled clinical trial, 44 outpatients of both genders aged 4-12 years with a diagnosis of AD and a score of ≥12 on the Aberrant Behavior Checklist-Community (ABC-C) irritability subscale were included. Mean change of ABC-C irritability subscale score as primary outcome, change in other ABC-C subscale scores and partial and complete responses were compared between two groups. Twenty patients completed the trial in each group. Level of reduction and effect of time×treatment interaction in the treatment group were significant for irritability (P=0.03), lethargy/social withdrawal (P=0.04) and hyperactivity/non-compliance (P=0.03) but not for stereotypic behavior and inappropriate speech subscales compared with the placebo group. Vomiting and headache were the most frequent reported side-effects. Results of this preliminary study indicate positive effects of pioglitazone compared with placebo in improving the behavioral symptoms of AD.

The case of galantamine: repurposing and late blooming of a cholinergic drug

Galantamine is a reversible inhibitor of cholinesterases and an allosteric modulator of neuronal nicotinic acetylcholine receptors which restores reduced cholinergic tone in the central and peripheral nervous system. Characterized in the early 1950s in Bulgaria, it saw limited use for paralytic and neuropathic conditions until the cholinergic hypothesis of Alzheimer’s disease opened totally new perspectives for its utility. Although constricted supplies at extremely high prices and a fragmented patent situation made its repurposing challenging, galantamine was globally launched as an Alzheimer’s disease drug in 2000. Many other possible uses have been clinically investigated, and might yet develop into another drug career. This case study is presented as an example for classical on-target drug repurposing and the challenges that such a project can face.

Acetylcholine is a key neurotransmitter that regulates many functions in the CNS, as well as in other body organs, through the cholinergic system. Galantamine is a well-known alkaloid drug that modulates this system toward a higher cholinergic tone, and has been put to several therapeutic uses during the past decades, most recently, for Alzheimer’s disease. However, its known actions might allow repurposing toward even more applications not only in psychiatry and neurology but also in eye medicine and even in immunology. This article summarizes the claims, the evidence and the potential of galantamine beyond its currently approved uses.

Predictors of placebo response in pharmacological and dietary supplement treatment trials in pediatric autism spectrum disorder: a meta-analysis

Large placebo responses in many clinical trials limit our capacity to identify effective therapeutics. Although it is often assumed that core behaviors in children with autism spectrum disorders (ASDs) rarely remit spontaneously, there has been limited investigation of the size of the placebo response in relevant clinical trials. These trials also rely on caregiver and clinical observer reports as outcome measures. The objectives of this meta-analysis are to identify the pooled placebo response and the predictors of placebo response in pharmacological and dietary supplement treatment trials for participants with a diagnosis of ASD. Randomized controlled trials (RCTs) in pediatric ASD, conducted between 1980 and August 2014, were identified through a search of Medline, EMBASE, Web of Science, Cochrane Database of Systematic Reviews and clinicaltrials.gov. RCTs of at least 14 days duration, comparing the treatment response for an oral active agent and placebo using at least one of the common outcome measures, were included. Analysis of 25 data sets (1315 participants) revealed a moderate effect size for overall placebo response (Hedges' g=0.45, 95% confidence interval (0.34-0.56), P<0.001). Five factors were associated with an increase in response to placebo, namely: an increased response to the active intervention; outcome ratings by clinicians (as compared with caregivers); trials of pharmacological and adjunctive interventions; and trials located in Iran. There is a clear need for the identification of objective measures of change in clinical trials for ASD, such as evaluation of biological activity or markers, and for consideration of how best to deal with placebo response effects in trial design and analyses.

Neuronal effects of nicotine during auditory selective attention

RATIONALE

Although the attention-enhancing effects of nicotine have been behaviorally and neurophysiologically well-documented, its localized functional effects during selective attention are poorly understood.

OBJECTIVES

In this study, we examined the neuronal effects of nicotine during auditory selective attention in healthy human nonsmokers. We hypothesized to observe significant effects of nicotine in attention-associated brain areas, driven by nicotine-induced increases in activity as a function of increasing task demands.

METHODS

A single-blind, prospective, randomized crossover design was used to examine neuronal response associated with a go/no-go task after 7 mg nicotine or placebo patch administration in 20 individuals who underwent functional magnetic resonance imaging at 3T. The task design included two levels of difficulty (ordered vs. random stimuli) and two levels of auditory distraction (silence vs. noise).

RESULTS

Significant treatment × difficulty × distraction interaction effects on neuronal response were observed in the hippocampus, ventral parietal cortex, and anterior cingulate. In contrast to our hypothesis, U and inverted U-shaped dependencies were observed between the effects of nicotine on response and task demands, depending on the brain area.

CONCLUSIONS

These results suggest that nicotine may differentially affect neuronal response depending on task conditions. These results have important theoretical implications for understanding how cholinergic tone may influence the neurobiology of selective attention.

Nicotinic ACh receptors as therapeutic targets in CNS disorders

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor (nAChR) channels. These receptors are widely distributed throughout the central nervous system (CNS), being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however, the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer's disease, AD), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain.

Advanced pharmacotherapy evidenced by pathogenesis of autism spectrum disorder

In clinical practice, pharmacological treatment is mostly focused on behavioral symptoms in everyday life. Nevertheless, persistent effort continues to develop medication for causal treatment. Recent changes in diagnostic criteria from Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM-IV-TR) to DSM-5 would affect not only diagnosing approaches, but also therapeutic approaches. Because previous pervasive developmental disorders have been integrated into a single entity, the autism spectrum disorder (ASD), we have to prepare for what medications are valuable for the ASD. In this article, we reviewed the following etiological treatment: acetylcholine and glutamate related medicine; amino acid medicine such as secretin, endogenous opioid, and oxytocin; complementary and alternative medicine such as chelating agents, vitamins, and omega-3; promising drugs related to the scope of pharmacogenetics currently under study.

An update on medication management of behavioral disorders in autism

Autism spectrum disorder is often comorbid with behavioral disturbances such as irritability, aggression and hyperactivity. Throughout the mid 2000s, several large-scale controlled clinical trials were published leading to the approval of two medications (aripiprazole and risperidone) for treatment of irritability in this condition. This review serves as an update regarding new research findings regarding psychopharmacology for children and adolescents with ASD. In summary, the past five years have yielded no further approved medications with ASD as a primary indication. Important new research results include 1) long-term safety and efficacy data (52 week) regarding treatment with aripiprazole for irritability, 2) consensus regarding potential harm from SSRIs for treatment of repetitive behaviors in children/ adolescents with ASD, 3) a randomized controlled trial showing modest benefits from atomoxetine on hyperactivity, 4) many novel agents currently under investigation.

Potential therapeutic use of the ketogenic diet in autism spectrum disorders

The ketogenic diet (KGD) has been recognized as an effective treatment for individuals with glucose transporter 1 (GLUT1) and pyruvate dehydrogenase (PDH) deficiencies as well as with epilepsy. More recently, its use has been advocated in a number of neurological disorders prompting a newfound interest in its possible therapeutic use in autism spectrum disorders (ASD). One study and one case report indicated that children with ASD treated with a KGD showed decreased seizure frequencies and exhibited behavioral improvements (i.e., improved learning abilities and social skills). The KGD could benefit individuals with ASD affected with epileptic episodes as well as those with either PDH or mild respiratory chain (RC) complex deficiencies. Given that the mechanism of action of the KGD is not fully understood, caution should be exercised in ASD cases lacking a careful biochemical and metabolic characterization to avoid deleterious side effects or refractory outcomes.