Potential therapeutic use of the ketogenic diet in autism spectrum disorders

Vocal communication in asocial BTBR mice is more malleable by a ketogenic diet in juveniles than adults

Deficits in social communication and language development are a hallmark of autism spectrum disorder currently with no effective approaches to reduce the negative impact. Interventional studies using animal models have been very limited in demonstrating improved vocal communication. Autism has been proposed to involve metabolic dysregulation. Ketogenic diet (KD) is a metabolism-based therapy for medically intractable epilepsy, and its applications in other neurological conditions have been increasingly tested. However, how KD would affect vocal communication has not been explored. The BTBR mouse strain is widely used to model asocial phenotypes. They display robust and pronounced deficits in vocalization during social interaction, and have metabolic changes implicated in autism. We investigated the effects of KD on ultrasonic vocalizations (USVs) in juvenile and adult BTBR mice during male-female social encounters. After a brief treatment with KD, the number, spectral bandwidth, and much of the temporal structure of USVs were robustly closer to control levels in both juvenile and adult BTBR mice. Composition of call categories and transitioning between individual call subtypes were more effectively altered to more closely align with the control group in juvenile BTBR mice. Together, our data provide further support to the hypothesis that metabolism-based dietary intervention could modify disease expression, including core symptoms, in autism. Future studies should tease apart the molecular mechanisms of KD's effects on vocalization.

Brain-gut-brain axis, nutrition, and autism spectrum disorders: a review

Autism is a neurological disorder that affects social skills and behavior. A significant number of children with autism spectrum disorders (ASDs) may not display noticeable symptoms until they reach the age of three or older. Several factors, including genetic and environmental issues, could affect the progression of ASD in children. Dietary behavior or administration may have a crucial role in the development of autism. Epidemiological investigations have demonstrated that environmental influences play a significant role in how changes in diet can affect behavior and physiology. However, exclusion diets have not been thoroughly studied in relation to this effect. Atypical food behaviors, altered nutritional profiles, and being overweight, obese, or underweight are all associated with autism in children. Overweight or underweight was common in children with autism, but it was not necessarily uncommon in children with normal growth. Moreover, deficiencies in certain vitamins (B12, B9, and D), minerals (calcium and iron), fatty acids (omega-3 and -6), energy, and protein have been documented in children with ASD. The deficiency of these nutrients may lead to gastrointestinal (GI) symptoms and change the microbiota in children with ASD. Some nutritional interventions could help individuals with ASD to improve their mental health. Recognizing dietary habits and nutrient requirements can help in planning the best overall treatment for autism. This review discusses GI symptoms and disorders related to nutrition and nutrient-dense diets for ASD.

Metabolic Shift and Hyperosmolarity Underlie Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is both a poorly understood and devastating disease. Here, we analyze the physico-chemical forces at stake, including osmolarity, redox shift, and pressure due to inflammation. Hyperosmolarity plays a key role in diseases of the anterior segment of the eye such as glaucoma, cataracts or dry eyes, and corneal ulceration. However, its role in macular degeneration has been largely overlooked. Hyperosmolarity is responsible for metabolic shifts such as aerobic glycolysis which increases lactate secretion by Muller cells. Increased osmolarity will also cause neoangiogenesis and cell death. Because of its unique energetic demands, the macula is very sensitive to metabolic shifts. As a proof of concept, subretinal injection of drugs increasing hyperosmolarity such as polyethylene glycol causes neoangiogenesis and drusen-like structures in rodents. The link between AMD and hyperosmolarity is reinforced by the fact that treatments aiming to restore mitochondrial activity, such as lipoic acid and/or methylene blue, have been experimentally shown to be effective. We suggest that metabolic shift, inflammation, and hyperosmolarity are hallmarks in the pathogenesis and treatment of AMD.

Dietary and Metabolic Approaches for Treating Autism Spectrum Disorders, Affective Disorders and Cognitive Impairment Comorbid with Epilepsy: A Review of Clinical and Preclinical Evidence

Epilepsy often occurs with other neurological disorders, such as autism, affective disorders, and cognitive impairment. Research indicates that many neurological disorders share a common pathophysiology of dysfunctional energy metabolism, neuroinflammation, oxidative stress, and gut dysbiosis. The past decade has witnessed a growing interest in the use of metabolic therapies for these disorders with or without the context of epilepsy. Over one hundred years ago, the high-fat, low-carbohydrate ketogenic diet (KD) was formulated as a treatment for epilepsy. For those who cannot tolerate the KD, other diets have been developed to provide similar seizure control, presumably through similar mechanisms. These include, but are not limited to, the medium-chain triglyceride diet, low glycemic index diet, and calorie restriction. In addition, dietary supplementation with ketone bodies, polyunsaturated fatty acids, or triheptanoin may also be beneficial. The proposed mechanisms through which these diets and supplements work to reduce neuronal hyperexcitability involve normalization of aberrant energy metabolism, dampening of inflammation, promotion of endogenous antioxidants, and reduction of gut dysbiosis. This raises the possibility that these dietary and metabolic therapies may not only exert anti-seizure effects, but also reduce comorbid disorders in people with epilepsy. Here, we explore this possibility and review the clinical and preclinical evidence where available.

Ketogenic diet and behavior: insights from experimental studies

As a journal page for full details. The ketogenic diet (KD) has been established as a treatment for epilepsy, but more recently it has been explored as an alternative or add-on therapy for many other diseases ranging from weight loss to neurological disorders. Animal models are widely used in studies investigating the therapeutic effects of the KD as well as underlying mechanisms. Especially in the context of neurological, psychiatric, and neurodevelopmental disorders essential endpoints are assessed by behavioral and motor tests. Here we summarized research evaluating the influence of the KD on cognition, depressive and anxiety-related behaviors, and social and nutritional behaviors of laboratory rodents. Each section contains a brief description of commonly used behavioral tests highlighting their limitations. Ninety original research articles, written in English, performed on mice or rats, providing measurement of blood beta-hydroxybutyrate (BHB) levels and behavioral evaluation were selected for the review. The majority of research performed in various disease models shows that the KD positively impacts cognition. Almost an equal number of studies report a reduction or no effect of the KD on depressive-related behaviors. For anxiety-related behaviors, the majority of studies show no effect. Despite the increasing use of the KD in weight loss and its appetite-reducing properties the behavioral evaluation of appetite regulation has not been addressed in preclinical studies. This review provides an overview of the behavioral effects of nutritional ketosis addressed to a broad audience of scientists interested in the KD field but not necessarily specializing in behavioral tests.

A Review of the Nutritional Approach and the Role of Dietary Components in Children with Autism Spectrum Disorders in Light of the Latest Scientific Research

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects several areas of mental development. The onset of ASD occurs in the first few years of life, usually before the age of 3 years. Proper nutrition is important to ensure that an individual's nutrient and energy requirements are met, and it can also have a moderating effect on the progression of the disorder. A systematic database search was conducted as a narrative review to determine whether nutrition and specific diets can potentially alter gastrointestinal symptoms and neurobehavioral disorders. Databases such as Science Direct, PubMed, Scopus, Web of Science (WoS), and Google Scholar were searched to find studies published between 2000 and September 2023 on the relationship between ASD, dietary approaches, and the role of dietary components. The review may indicate that despite extensive research into dietary interventions, there is a general lack of conclusive scientific data about the effect of therapeutic diets on ASD; therefore, no definitive recommendation can be made for any specific nutritional therapy as a standard treatment for ASD. An individualized dietary approach and the dietician's role in the therapeutic team are very important elements of every therapy. Parents and caregivers should work with nutrition specialists, such as registered dietitians or healthcare providers, to design meal plans for autistic individuals, especially those who would like to implement an elimination diet.

A Spectrum of Solutions: Unveiling Non-Pharmacological Approaches to Manage Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disorder that causes difficulty while socializing and communicating and the performance of stereotyped behavior. ASD is thought to have a variety of causes when accompanied by genetic disorders and environmental variables together, resulting in abnormalities in the brain. A steep rise in ASD has been seen regardless of the numerous behavioral and pharmaceutical therapeutic techniques. Therefore, using complementary and alternative therapies to treat autism could be very significant. Thus, this review is completely focused on non-pharmacological therapeutic interventions which include different diets, supplements, antioxidants, hormones, vitamins and minerals to manage ASD. Additionally, we also focus on complementary and alternative medicine (CAM) therapies, herbal remedies, camel milk and cannabiodiol. Additionally, we concentrate on how palatable phytonutrients provide a fresh glimmer of hope in this situation. Moreover, in addition to phytochemicals/nutraceuticals, it also focuses on various microbiomes, i.e., gut, oral, and vaginal. Therefore, the current comprehensive review opens a new avenue for managing autistic patients through non-pharmacological intervention.

Diet in treatment of autism spectrum disorders

Altering the diet to treat disease dates to c. 400 BC when starvation was used to reduce seizures in persons with epilepsy. The current diversity of symptomology and mechanisms underlying autism spectrum disorders (ASDs) and a corresponding lack of disorder-specific effective treatments prompts an evaluation of diet as a therapeutic approach to improve symptoms of ASDs. In this review article, we summarize the main findings of nutritional studies in ASDs, with an emphasis on the most common monogenic cause of autism, Fragile X Syndrome (FXS), and the most studied dietary intervention, the ketogenic diet as well as other dietary interventions. We also discuss the gut microbiota in relation to pre- and probiotic therapies and provide insight into future directions that could aid in understanding the mechanism(s) underlying dietary efficacy.

Treatment of Autism Spectrum Disorders by Mitochondrial-targeted Drug: Future of Neurological Diseases Therapeutics

Autism is a neurodevelopmental disorder with a complex etiology that might involve environmental and genetic variables. Recently, some epidemiological studies conducted in various parts of the world have estimated a significant increase in the prevalence of autism, with 1 in every 59 children having some degree of autism. Since autism has been associated with other clinical abnormalities, there is every possibility that a sub-cellular component may be involved in the progression of autism. The organelle remains a focus based on mitochondria's functionality and metabolic role in cells. Furthermore, the mitochondrial genome is inherited maternally and has its DNA and organelle that remain actively involved during embryonic development; these characteristics have linked mitochondrial dysfunction to autism. Although rapid stride has been made in autism research, there are limited studies that have made particular emphasis on mitochondrial dysfunction and autism. Accumulating evidence from studies conducted at cellular and sub-cellular levels has indicated that mitochondrial dysfunction's role in autism is more than expected. The present review has attempted to describe the risk factors of autism, the role of mitochondria in the progression of the disease, oxidative damage as a trigger point to initiate mitochondrial damage, genetic determinants of the disease, possible pathogenic pathways and therapeutic regimen in vogue and the developmental stage. Furthermore, in the present review, an attempt has been made to include the novel therapeutic regimens under investigation at different clinical trial stages and their potential possibility to emerge as promising drugs against ASD.

The Role of Gut Dysbiosis in the Pathophysiology of Neuropsychiatric Disorders

Mounting evidence shows that the complex gut microbial ecosystem in the human gastrointestinal (GI) tract regulates the physiology of the central nervous system (CNS) via microbiota and the gut-brain (MGB) axis. The GI microbial ecosystem communicates with the brain through the neuroendocrine, immune, and autonomic nervous systems. Recent studies have bolstered the involvement of dysfunctional MGB axis signaling in the pathophysiology of several neurodegenerative, neurodevelopmental, and neuropsychiatric disorders (NPDs). Several investigations on the dynamic microbial system and genetic-environmental interactions with the gut microbiota (GM) have shown that changes in the composition, diversity and/or functions of gut microbes (termed "gut dysbiosis" (GD)) affect neuropsychiatric health by inducing alterations in the signaling pathways of the MGB axis. Interestingly, both preclinical and clinical evidence shows a positive correlation between GD and the pathogenesis and progression of NPDs. Long-term GD leads to overstimulation of hypothalamic-pituitary-adrenal (HPA) axis and the neuroimmune system, along with altered neurotransmitter levels, resulting in dysfunctional signal transduction, inflammation, increased oxidative stress (OS), mitochondrial dysfunction, and neuronal death. Further studies on the MGB axis have highlighted the significance of GM in the development of brain regions specific to stress-related behaviors, including depression and anxiety, and the immune system in the early life. GD-mediated deregulation of the MGB axis imbalances host homeostasis significantly by disrupting the integrity of the intestinal and blood-brain barrier (BBB), mucus secretion, and gut immune and brain immune functions. This review collates evidence on the potential interaction between GD and NPDs from preclinical and clinical data. Additionally, we summarize the use of non-therapeutic modulators such as pro-, pre-, syn- and post-biotics, and specific diets or fecal microbiota transplantation (FMT), which are promising targets for the management of NPDs.

The effects of a primary care low-carbohydrate, high-fat dietary educational intervention on laboratory and anthropometric data of patients with chronic disease: a retrospective cohort chart review

BACKGROUND

Low-carbohydrate and high-fat (LCHF) diets are shown to have health benefits such as weight loss and improved cardiovascular health. Few studies, however, on LCHF diets have been completed in a real-world primary care setting over an extended period of time.

OBJECTIVES

To examine the efficacy of a low-carbohydrate, high-fat dietary educational intervention delivered in a family practice setting on weight, body mass index (BMI), blood pressure, glycated haemoglobin (HbA1c), fasting insulin, estimated glomerular filtration rate (eGFR), and albumin to creatinine ratio (ACR). A secondary objective was to determine whether compliance to the program had an effect on outcomes.

METHODS

In this retrospective chart review, we collected laboratory and anthropometric data from an electronic medical record system for patients (n = 122) at least 19 years of age, who attended at least 2 LCHF educational sessions between January 2018 and May 2020. Pre-post mean differences of outcome were analysed using paired sample t-tests. Independent sample t-tests examined the effect of compliance on the outcomes.

RESULTS

Statistically significant reductions in weight (3.96 kg [P < 0.001]) and BMI (1.46 kg/m2 [P = 0.001]) were observed. Compared with patients who participated in ≤5 educational visits, patients who participated in >5 visits showed trends towards more clinically significant changes in weight, BMI, systolic blood pressure, diastolic blood pressure, HbA1c, eGFR, and ACR.

CONCLUSION

Improvements in weight and BMI indicate the utility of providing LCHF health promotion interventions in primary care settings. Greater compliance to LCHF interventions results in greater improvement in laboratory and anthropometric outcomes, including HbA1c.

Brain-Derived Neurotrophic Factor: A Connecting Link Between Nutrition, Lifestyle, and Alzheimer’s Disease

Brain-derived neurotrophic factor (BDNF) involving tropomyosin kinase B and low affinity p75 neurotropin receptors is the most abundant and researched neurotropins in mammal’s brain. It is one of the potential targets for therapeutics in Alzheimer’s disease (AD) owing to its key role in synaptic plasticity. Low levels of BDNF are implicated in the pathophysiology of neurological diseases including AD. However, a healthy lifestyle, exercise, and dietary modifications are shown to positively influence insulin regulation in the brain, reduce inflammation, and up-regulate the levels of BDNF, and are thus expected to have roles in AD. In this review, the relationship between BDNF, mental health, and AD is discussed. Insights into the interrelationships between nutrition, lifestyle, and environment with BDNF and possible roles in AD are also provided in the review. The review sheds light on the possible new therapeutic targets in neurodegenerative diseases.

Effects of nutritional interventions in children and adolescents with autism spectrum disorder: an overview based on a literature review

Background: Nutrition is important in autism spectrum disorder (ASD). Because nutritional problems of children with ASD can lead to nutritional deficiencies and this can also directly or indirectly affect symptoms related to autism. We investigated the effect of diet and supplementation treatments on gastrointestinal, behavioral or sleep problems based on the results of literature review. Methods: We generated four questions based on literature. We carried out title and abstract-based search using the Web of Science database. Of 4580 abstracts were identified, 192 papers were reviewed and 55 papers precisely meeting the inclusion criteria. Results: The studies examining the effects of vitamins, minerals, probiotics, and other supplements on ASD symptoms had different dosages, different treatment durations, small sample sizes and used different scales for evaluation. The results of the studies of the effectiveness of Gluten-Free and Casein-Free (GFCF) and ketogenic diet to reduce gastrointestinal, behavioral and sleeping problems in children and adolescents were contradictory. Conclusions: It is not possible to suggest the GFCF and/or ketogenic diet, vitamins, minerals and probiotics to individual with ASD based on the available evidence. By planning a sufficient and balanced diet, it should be aimed to prevent nutrient deficiency and to ensure growth in accordance with the age in children with ASD.

Neuroinflammation: Molecular Mechanisms And Therapeutic Perspectives

BACKGROUND

Neuroinflammation is a key component in the etiopathogenesis of neurological diseases and brain aging. This process involves the brain immune system that modulates synaptic functions and protects neurons from infection or damage. Hence, the knowledge of neuroinflammation related pathways and modulation by drugs or natural compounds is functional to developing therapeutic strategies aimed at preserving, maintaining and restoring brain health.

OBJECTIVE

This review article summarizes the basics of neuroinflammation and related signaling pathways, the success of the dietary intervention in clinical practice and the possible development of RNA-based strategies for treating neurological diseases.

METHODS

Pubmed search from 2012 to 2022 with the keywords neuroinflammation and molecular mechanisms in combination with diet, miRNA and non-coding RNA.

RESULTS

Glial cells-play a crucial role in neuroinflammation, but several pathways can be activated in response to different inflammatory stimuli, inducing cell death by apoptosis, pyroptosis or necroptosis. The dietary intervention has immunomodulatory effects and could limit the inflammatory process induced by microglia and astrocytes. Thus by inhibiting neuroinflammation and improving the symptoms of a variety of neurological diseases, diet exerts pleiotropic neuroprotective effects independently from the spectrum of pathophysiological mechanisms underlying the specific disorder. Furthermore, data from animal models revealed that altered expression of specific noncoding RNAs, in particular microRNAs, contributes to neuroinflammatory diseases; consequently, RNA-based strategies may be promising to alleviate the consequences of neuroinflammation.

CONCLUSION

Further studies are needed to identify the molecular pathways and the new pharmacological targets in neuroinflammation to lay the basis for more effective and selective therapies to be applied, in parallel to dietary intervention, in the treatment of neuroinflammation-based diseases.

Gastrointestinal involvement of autism spectrum disorder: focus on gut microbiota

INTRODUCTION

Autism spectrum disorder (ASD) is a neurodevelopmental disorder typical of early age, characterized by impaired communication, social interaction, and repetitive behaviors. ASD patients frequently suffer from gastrointestinal (GI) symptoms. Neuro-psychological functions, intestinal homeostasis, and functional GI disturbances are modulated by the gut microbiota through the so-called 'microbiota-gut-brain axis'.

AREAS COVERED

Literature regarding GI symptoms among the ASD community as well as the involvement and modulation of the gut microbiota in GI disturbances of ASD patients was searched. Constipation, diarrhea, reflux, abdominal bloating, pain, and discomfort are reported with variable prevalence. ASD is characterized by a reduction of Bacteroidetes/Firmicutes, of the abundance of Bacteroidetes and other imbalances. ASD patients with GI symptoms present microbial changes with plausible relation with deficiency of digestive enzymes, carbohydrate malabsorption, selective eating, bacterial toxins, serotonin metabolism, and inflammation. The strategies to mitigate the GI distress through the gut microbiota modulation comprise antimicrobials, probiotics, prebiotics, fecal microbiota transplantation, and dietary intervention.

EXPERT OPINION

The modulation of the gut microbiota in ASD individuals with GI disturbances seems a promising target for the future medicine. A standardization of the research strategies for large-scale studies together with a focus on poorly explored fields is necessary to strengthen this hypothesis.

Genetic Approaches Using Zebrafish to Study the Microbiota-Gut-Brain Axis in Neurological Disorders

The microbiota-gut-brain axis (MGBA) is a bidirectional signaling pathway mediating the interaction of the microbiota, the intestine, and the central nervous system. While the MGBA plays a pivotal role in normal development and physiology of the nervous and gastrointestinal system of the host, its dysfunction has been strongly implicated in neurological disorders, where intestinal dysbiosis and derived metabolites cause barrier permeability defects and elicit local inflammation of the gastrointestinal tract, concomitant with increased pro-inflammatory cytokines, mobilization and infiltration of immune cells into the brain, and the dysregulated activation of the vagus nerve, culminating in neuroinflammation and neuronal dysfunction of the brain and behavioral abnormalities. In this topical review, we summarize recent findings in human and animal models regarding the roles of the MGBA in physiological and neuropathological conditions, and discuss the molecular, genetic, and neurobehavioral characteristics of zebrafish as an animal model to study the MGBA. The exploitation of zebrafish as an amenable genetic model combined with in vivo imaging capabilities and gnotobiotic approaches at the whole organism level may reveal novel mechanistic insights into microbiota-gut-brain interactions, especially in the context of neurological disorders such as autism spectrum disorder and Alzheimer's disease.

Effects of Diet, Nutrition, and Exercise in Children With Autism and Autism Spectrum Disorder: A Literature Review

Diet and nutrition play an important and essential role in everyone's life. It helps build a healthy body and a strong mind. We know that food rich in nutrients can remove toxins from the body, make an excellent immune system, curb hunger, and prevent obesity. Obesity is one of the most concerning, alarming, and fastest-growing pandemics. It affects not only adults but also adolescents and children. The disease's early-onset calls for prompt attention to control the physical, psychological, financial, and social burden it creates. Children with autism and autism spectrum disorders (ASDs) are commonly affected by eating disorders. Their preference for energy-dense food with low nutrition can alter their metabolism, leading to the accumulation of oxidative radicals, causing them to deteriorate mentally and physically. Although dieting and losing weight are now commonly seen in the general population, it has become hard to bring awareness to children with special needs about diet, nutrition, and obesity. Despite efforts, parents of such children usually cannot help control the eating because tantrums and behavioral problems are common. It is now imperative for doctors and parents to work alongside nutritionists and dieticians to help these children eat healthy to be fit and improve the quality of life.

Mitochondrial Dysfunction in Autism Spectrum Disorder: Unique Abnormalities and Targeted Treatments

Several lines of evidence implicate mitochondria in the pathophysiology of autism spectrum disorder (ASD). In this review, we outline some of the evidence supporting this notion, as well as discuss novel abnormalities in mitochondrial function that appear to be related to ASD, and treatments that both target mitochondria and have evidence of usefulness in the treatment of ASD in clinical trials. A suspicion of the mitochondrion's involvement in ASD can be traced back to 1985 when lactic acidosis was noted in a subset of children with ASD. A large population-based study in 2007 confirmed this notion and found that a subset of children with ASD (∼4%) could be diagnosed with a definite mitochondrial disease. Further studies suggested that children with ASD and mitochondrial disease may have certain characteristics such as fatigability, gastrointestinal disorders, unusual types of neurodevelopmental regression, seizures/epilepsy, and motor delay. Further research examining biomarkers of mitochondrial dysfunction and electron transport chain activity suggest that abnormalities of mitochondrial function could affect a much higher number of children with ASD, perhaps up to 80%. Recent research has identified a type of dysfunction of mitochondria in which the activity of the electron transport chain is significantly increased. This novel type of mitochondrial dysfunction may be associated with environmental exposures and neurodevelopmental regression. Several treatments that target mitochondria appear to have evidence for use in children with ASD, including cofactors such as L-Carnitine and the ketogenic diet. Although the understanding of the involvement of mitochondria in ASD is evolving, the mitochondrion is clearly a novel molecular target which can be helpful in understanding the etiology of ASD and treatments that may improve function of children with ASD.

Aberrant Mitochondrial Morphology and Function in the BTBR Mouse Model of Autism Is Improved by Two Weeks of Ketogenic Diet

Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder that exhibits a common set of behavioral and cognitive impairments. Although the etiology of ASD remains unclear, mitochondrial dysfunction has recently emerged as a possible causative factor underlying ASD. The ketogenic diet (KD) is a high-fat, low-carbohydrate diet that augments mitochondrial function, and has been shown to reduce autistic behaviors in both humans and in rodent models of ASD. The aim of the current study was to examine mitochondrial bioenergetics in the BTBR mouse model of ASD and to determine whether the KD improves mitochondrial function. We also investigated changes in mitochondrial morphology, which can directly influence mitochondrial function. We found that BTBR mice had altered mitochondrial function and exhibited smaller more fragmented mitochondria compared to C57BL/6J controls, and that supplementation with the KD improved both mitochondrial function and morphology. We also identified activating phosphorylation of two fission proteins, pDRP1^S616 and pMFF^S146, in BTBR mice, consistent with the increased mitochondrial fragmentation that we observed. Intriguingly, we found that the KD decreased pDRP1^S616 levels in BTBR mice, likely contributing to the restoration of mitochondrial morphology. Overall, these data suggest that impaired mitochondrial bioenergetics and mitochondrial fragmentation may contribute to the etiology of ASD and that these alterations can be reversed with KD treatment.

The Role of Microbiome, Dietary Supplements, and Probiotics in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a serious neurodevelopmental disorder characterized by the impairment of the cognitive function of a child. Studies suggested that the intestinal microbiota has a critical role in the function and regulation of the central nervous system, neuroimmune system and neuroendocrine system. Any adverse changes in the gut–brain axis may cause serious disease. Food preferences and dietary patterns are considered as key in influencing the factors of ASD development. Several recent reviews narrated the importance of dietary composition on controlling or reducing the ASD symptoms. It has been known that the consumption of probiotics confers several health benefits by positive amendment of gut microbiota. The influence of probiotic intervention in children with ASD has also been reported and it has been considered as an alternative and complementary therapeutic supplement for ASD. The present manuscript discusses the role of microbiota and diet in the development of ASD. It also summarizes the recent updates on the influence of dietary supplements and the beneficial effect of probiotics on ASD symptoms. An in-depth literature survey suggested that the maternal diet and lifestyle are greatly associated with the development of ASD and other neurodevelopmental disorders. Mounting evidences have confirmed the alteration in the gut microbial composition in children suffering from ASD. However, the unique profile of microbiome has not yet been fully characterized due to the heterogeneity of patients. The supplementation of probiotics amended the symptoms associated with ASD but the results are inconclusive. The current study recommends further detailed research considering the role of microbiome, diet and probiotics in the development and control of ASD.

Preclinical testing of the ketogenic diet in fragile X mice

The ketogenic diet is highly effective at attenuating seizures in refractory epilepsy, and accumulating evidence in the literature suggests that it may be beneficial in autism. To our knowledge, no one has studied the ketogenic diet in any fragile X syndrome (FXS) model. FXS is the leading known genetic cause of autism. Herein, we tested the effects of chronic ketogenic diet treatment on seizures, body weight, ketone and glucose levels, diurnal activity levels, learning and memory, and anxiety behaviors in Fmr1^KO and littermate control mice as a function of age. The ketogenic diet selectively attenuates seizures in male but not female Fmr1^KO mice and differentially affects weight gain and diurnal activity levels dependent on Fmr1 genotype, sex and age.

Dietary Approaches to the Management of Autism Spectrum Disorders

This chapter reviews the literature surrounding autism spectrum disorders (ASD) and their relation to gastrointestinal (GI), behavioral, neurological, and immunological functioning. Individuals with ASD often have poor GI health, including bowel motility issues, autoimmune and/or other adverse responses to certain foods, and lack of necessary nutrient absorption. These issues may be caused or exacerbated by restrictive behavioral patterns (e.g., preference for sweet and salty foods and/or refusal of healthy foods). Those individuals with GI issues tend to demonstrate more behavioral deficits (e.g., irritability, agitation, hyperactivity) and also tend to have an imbalance in overall gut microbiome composition, thus corroborating several studies that have implicated brain-gut pathways as potential mediators of behavioral dysfunction.We examine the literature regarding dietary approaches to managing ASDs, including elimination diets for gluten, casein, or complex carbohydrates, a ketogenic diet, and a low oxalate diet. We also explore the research examining dietary supplements such as fatty acids, pro- and prebiotics, vitamins, minerals, glutathione, phytochemicals, and hormones. The research on dietary approaches to managing ASDs is limited and the results are mixed. However, a few approaches, such as the gluten-free/casein-free diet, fatty acid supplementation, and pre/probiotics have generally demonstrated improved GI and associated behavioral symptoms. Given that GI issues seem to be overrepresented in ASD populations, and that GI issues have been associated with a number behavioral and neurological deficits, dietary manipulation may offer a cheap and easily implemented approach to improve the lives of those with ASD.

Nutritional interventions for autism spectrum disorder

Autism spectrum disorder (ASD) is an increasingly prevalent neurodevelopmental disorder with considerable clinical heterogeneity. With no cure for the disorder, treatments commonly center around speech and behavioral therapies to improve the characteristic social, behavioral, and communicative symptoms of ASD. Gastrointestinal disturbances are commonly encountered comorbidities that are thought to be not only another symptom of ASD but to also play an active role in modulating the expression of social and behavioral symptoms. Therefore, nutritional interventions are used by a majority of those with ASD both with and without clinical supervision to alleviate gastrointestinal and behavioral symptoms. Despite a considerable interest in dietary interventions, no consensus exists regarding optimal nutritional therapy. Thus, patients and physicians are left to choose from a myriad of dietary protocols. This review, summarizes the state of the current clinical and experimental literature on nutritional interventions for ASD, including gluten-free and casein-free, ketogenic, and specific carbohydrate diets, as well as probiotics, polyunsaturated fatty acids, and dietary supplements (vitamins A, C, B6, and B12; magnesium and folate).

Translation deregulation in human disease

Advances in sequencing and high-throughput techniques have provided an unprecedented opportunity to interrogate human diseases on a genome-wide scale. The list of disease-causing mutations is expanding rapidly, and mutations affecting mRNA translation are no exception. Translation (protein synthesis) is one of the most complex processes in the cell. The orchestrated action of ribosomes, tRNAs and numerous translation factors decodes the information contained in mRNA into a polypeptide chain. The intricate nature of this process renders it susceptible to deregulation at multiple levels. In this Review, we summarize current evidence of translation deregulation in human diseases other than cancer. We discuss translation-related diseases on the basis of the molecular aberration that underpins their pathogenesis (including tRNA dysfunction, ribosomopathies, deregulation of the integrated stress response and deregulation of the mTOR pathway) and describe how deregulation of translation generates the phenotypic variability observed in these disorders.

Mitochondrial function and abnormalities implicated in the pathogenesis of ASD

Mitochondria are the powerhouse that generate over 90% of the ATP produced in cells. In addition to its role in energy production, the mitochondrion also plays a major role in carbohydrate, fatty acid, amino acid and nucleotide metabolism, programmed cell death (apoptosis), generation of and protection against reactive oxygen species (ROS), immune response, regulation of intracellular calcium ion levels and even maintenance of gut microbiota. With its essential role in bio-energetic as well as non-energetic biological processes, it is not surprising that proper cellular, tissue and organ function is dependent upon proper mitochondrial function. Accordingly, mitochondrial dysfunction has been shown to be directly linked to a variety of medical disorders, particularly neuromuscular disorders and increasing evidence has linked mitochondrial dysfunction to neurodegenerative and neurodevelopmental disorders such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Rett Syndrome (RS) and Autism Spectrum Disorders (ASD). Over the last 40 years there has been a dramatic increase in the diagnosis of ASD and, more recently, an increasing body of evidence indicates that mitochondrial dysfunction plays an important role in ASD development. In this review, the latest evidence linking mitochondrial dysfunction and abnormalities in mitochondrial DNA (mtDNA) to the pathogenesis of autism will be presented. This review will also summarize the results of several recent `approaches used for improving mitochondrial function that may lead to new therapeutic approaches to managing and/or treating ASD.

Therapeutic use of carbohydrate-restricted diets in an autistic child; a case report of clinical and 18FDG PET findings

The ketogenic diet (KD) is a high-fat, adequate-protein, and low-carbohydrate diet that has been used successfully in the treatment of refractory epilepsies for almost 100 years. There has been accumulating evidence to show that the KD may provide a therapeutic benefit in autism spectrum disorders, albeit by a yet-unknown mechanism. We report a case of a 6-year-old patient with high-functioning autism and subclinical epileptic discharges who responded poorly to several behavioural and psychopharmacological treatments. The patient was subsequently placed on the KD due to significant glucose hypometabolism in the brain as revealed by an 18FDG PET. As soon as one month after starting the KD, the patient's behavior and intellect improved (in regard to hyperactivity, attention span, abnormal reactions to visual and auditory stimuli, usage of objects, adaptability to changes, communication skills, fear, anxiety, and emotional reactions); these improvements continued until the end of the observation period at 16 months on the KD. The 18FDG PET, measured at 12 months on the KD, revealed that 18F-FDG uptake decreased markedly and diffusely in the whole cerebral cortex with a relatively low reduction in basal ganglia in comparison to the pre-KD assessment. It warrants further investigation if the 18FDG PET imaging could serve as a biomarker in identifying individuals with autism who might benefit from the KD due to underlying abnormalities related to glucose hypometabolism.

Dietary interventions for autism spectrum disorder: New perspectives from the gut-brain axis

There is still controversy surrounding the effectiveness of dietary interventions for autism spectrum disorder (ASD), namely the gluten-free/casein free diet and the ketogenic diet. Additionally, as studies mainly investigated their impact on ASD symptoms and behaviors, much remains unknown about their mechanisms of action and physiological effects. Given the recent surge of global interest in the gut-brain axis and its involvement in ASD, we underline the importance of understanding the physiological effects of such restrictive diets that remove certain nutritional items from one's diet. Some evidence has emerged with findings of the gut-microbial, inflammatory, and neuronal effects of these diets. We propose probiotics as a potential alternative that can serve similar biological purposes as these elimination diets and outline different physiological routes whereby probiotics can lead to improvements for individuals with ASD. We hope that future research can delineate the complete physiological effects of these diets. Such knowledge can guide the creation of more informed interventions, which conserve the components resulting in positive behavioral change while being less restrictive and devoid of the harmful effects of limiting certain nutrients.

Are therapeutic diets an emerging additional choice in autism spectrum disorder management?

BACKGROUND

A nutritional background has been recognized in the pathophysiology of autism and a series of nutritional interventions have been considered as complementary therapeutic options. As available treatments and interventions are not effective in all individuals, new therapies could broaden management options for these patients. Our aim is to provide current literature data about the effect of therapeutic diets on autism spectrum disorder.

DATA SOURCE

A systematic review was conducted by two reviewers independently. Prospective clinical and preclinical studies were considered.

RESULT

Therapeutic diets that have been used in children with autism include ketogenic and gluten/casein-free diet. We were able to identify 8 studies conducted in animal models of autism demonstrating a beneficial effect on neurophysiological and clinical parameters. Only 1 clinical study was found showing improvement in childhood autism rating scale after implementation of ketogenic diet. With regard to gluten/casein-free diet, 4 clinical studies were totally found with 2 of them showing a favorable outcome in children with autism. Furthermore, a combination of gluten-free and modified ketogenic diet in a study had a positive effect on social affect scores. No serious adverse events have been reported.

CONCLUSION

Despite encouraging laboratory data, there is controversy about the real clinical effect of therapeutic diets in patients with autism. More research is needed to provide sounder scientific evidence.

Autism, Mitochondria and Polybrominated Diphenyl Ether Exposure

BACKGROUND

Autism spectrum disorders (ASD) are a growing concern with more than 1 in every 68 children affected in the United States by age 8. Limited scientific advances have been made regarding the etiology of autism, with general agreement that both genetic and environmental factors contribute to this disorder.

OBJECTIVE

To explore the link between exposure to PBDE, mitochondrial dysfunction and autism risk.

RESULTS

Perinatal exposures to PBDEs may contribute to the etiology or morbidity of ASD including mitochondrial dysfunction based on (i) their increased environmental abundance and human exposures, (ii) their activity towards implicated in neuronal development and synaptic plasticity including mitochondria, and (iii) their bioaccumulation in mitochondria.

CONCLUSION

In this review, we propose that PBDE, and possibly other environmental exposures, during child development can induce or compound mitochondrial dysfunction, which in conjunction with a dysregulated antioxidant response, increase a child's susceptibility of autism.

Current nutritional approaches in managing autism spectrum disorder: A review

The link between nutrition and autism spectrum disorder (ASD), which is a complex developmental disorder manifesting itself in significant delays or deviation in interaction and communication, has provided a fresh point of view and signals that nutrition may have a role in the aetiology of ASD, as well as play an active role in treatment by alleviating symptoms.

OBJECTIVE

In this review study aimed at evaluating, with scientific and concrete proof, the current medical nutrition implementations on ASD, existing medical nutrition therapies have been addressed and their effects on ASD symptoms have been discussed in light of current research.

METHODS

We reviewed articles regarding the medical nutritional therapy of autism on current nutritional approaches selected from PubMed, Science Direct, EBSCO, and databases about autism and nutrition.

RESULTS

The research put forward that in individuals with ASD, while gluten-free/casein-free and ketogenic diets, camel milk, curcumin, probiotics, and fermentable foods can play a role in alleviating ASD symptoms, consumption of sugar, additives, pesticides, genetically modified organisms, inorganic processed foods, and hard-to-digest starches may aggravate symptoms.

DISCUSSION

Further prospective controlled trials with large sample sizes are needed before recommendations can be made regarding the ideal ASD diet. This review emphasizes the value of identifying current nutritional approaches specific to individuals with ASD and integrating their effects on symptoms to the conversation and presents suggestions for future research designed to identify medical nutrition therapies targeting this population to better understand the link between ASD and nutrition.

The ketogenic diet affects the social behavior of young male rats

The positive effects of the ketogenic diet (KD) on social behavior have been recently reported in patients and rodent models of autism spectrum disorder (ASD). Given the beneficial effects of the KD on epilepsy, mitochondrial function, carbohydrate metabolism, and inflammation, treatment based on the KD has the potential to reduce some of the ASD-associated symptoms, including abnormal social interactions. It is not known whether the KD influences sociability by reducing the pathological processes underlying ASD or through some independent mechanism. The aim of the present study was to evaluate the influence of the KD on the social behavior of rats. Four-week-old Long-Evans males were treated with the KD for 4 subsequent weeks. Afterwards, behavioral tests were performed in order to evaluate sociability, locomotor activity, working memory, and anxiety-related behaviors. Additionally we performed the social interaction test in animals that were receiving β-hydroxybutyrate or acetone. We have observed that rats fed with the KD showed increased social exploration in three different experimental settings. We did not observe any changes in the level of social interactions in animals treated with exogenous ketone bodies. The results did not show any difference in mobility or anxiety-related behaviors or working memory between the animals fed with the KD or standard rodent chow. In conclusion, we showed that the KD affects the social behavior of wild-type young adult male rats, which was not associated with other behavioral changes.

Metabolic Dysfunction Underlying Autism Spectrum Disorder and Potential Treatment Approaches

Autism spectrum disorder (ASD) is characterized by deficits in sociability and communication, and increased repetitive and/or restrictive behaviors. While the etio-pathogenesis of ASD is unknown, clinical manifestations are diverse and many possible genetic and environmental factors have been implicated. As such, it has been a great challenge to identify key neurobiological mechanisms and to develop effective treatments. Current therapies focus on co-morbid conditions (such as epileptic seizures and sleep disturbances) and there is no cure for the core symptoms. Recent studies have increasingly implicated mitochondrial dysfunction in ASD. The fact that mitochondria are an integral part of diverse cellular functions and are susceptible to many insults could explain how a wide range of factors can contribute to a consistent behavioral phenotype in ASD. Meanwhile, the high-fat, low-carbohydrate ketogenic diet (KD), used for nearly a century to treat medically intractable epilepsy, has been shown to enhance mitochondrial function through a multiplicity of mechanisms and affect additional molecular targets that may address symptoms and comorbidities of ASD. Here, we review the evidence for the use of metabolism-based therapies such as the KD in the treatment of ASD as well as emerging co-morbid models of epilepsy and autism. Future research directions aimed at validating such therapeutic approaches and identifying additional and novel mechanistic targets are also discussed.

Ketogenic diet improves behaviors in a maternal immune activation model of autism spectrum disorder

Prenatal factors influence autism spectrum disorder (ASD) incidence in children and can increase ASD symptoms in offspring of animal models. These may include maternal immune activation (MIA) due to viral or bacterial infection during the first trimesters. Unfortunately, regardless of ASD etiology, existing drugs are poorly effective against core symptoms. For nearly a century a ketogenic diet (KD) has been used to treat seizures, and recent insights into mechanisms of ASD and a growing recognition that immune/inflammatory conditions exacerbate ASD risk has increased interest in KD as a treatment for ASD. Here we studied the effects of KD on core ASD symptoms in offspring exposed to MIA. To produce MIA, pregnant C57Bl/6 mice were injected with the viral mimic polyinosinic-polycytidylic acid; after weaning offspring were fed KD or control diet for three weeks. Consistent with an ASD phenotype of a higher incidence in males, control diet-fed MIA male offspring were not social and exhibited high levels of repetitive self-directed behaviors; female offspring were unaffected. However, KD feeding partially or completely reversed all MIA-induced behavioral abnormalities in males; it had no effect on behavior in females. KD-induced metabolic changes of reduced blood glucose and elevated blood ketones were quantified in offspring of both sexes. Prior work from our laboratory and others demonstrate KDs improve relevant behaviors in several ASD models, and here we demonstrate clear benefits of KD in the MIA model of ASD. Together these studies suggest a broad utility for metabolic therapy in improving core ASD symptoms, and support further research to develop and apply ketogenic and/or metabolic strategies in patients with ASD.

Ketogenic diets improve behaviors associated with autism spectrum disorder in a sex-specific manner in the EL mouse

The core symptoms of autism spectrum disorder are poorly treated with current medications. Symptoms of autism spectrum disorder are frequently comorbid with a diagnosis of epilepsy and vice versa. Medically-supervised ketogenic diets are remarkably effective nonpharmacological treatments for epilepsy, even in drug-refractory cases. There is accumulating evidence that supports the efficacy of ketogenic diets in treating the core symptoms of autism spectrum disorders in animal models as well as limited reports of benefits in patients. This study tests the behavioral effects of ketogenic diet feeding in the EL mouse, a model with behavioral characteristics of autism spectrum disorder and comorbid epilepsy. Male and female EL mice were fed control diet or one of two ketogenic diet formulas ad libitum starting at 5 weeks of age. Beginning at 8 weeks of age, diet protocols continued and performance of each group on tests of sociability and repetitive behavior was assessed. A ketogenic diet improved behavioral characteristics of autism spectrum disorder in a sex- and test-specific manner; ketogenic diet never worsened relevant behaviors. Ketogenic diet feeding improved multiple measures of sociability and reduced repetitive behavior in female mice, with limited effects in males. Additional experiments in female mice showed that a less strict, more clinically-relevant diet formula was equally effective in improving sociability and reducing repetitive behavior. Taken together these results add to the growing number of studies suggesting that ketogenic and related diets may provide significant relief from the core symptoms of autism spectrum disorder, and suggest that in some cases there may be increased efficacy in females.

Plasma Biomarkers for Monitoring Brain Pathophysiology in FMR1 Premutation Carriers

Premutation carriers have a 55–200 CGG expansion in the fragile X mental retardation 1 (FMR1) gene. Currently, 1.5 million individuals are affected in the United States, and carriers are at risk of developing the late-onset neurodegenerative disorder Fragile X-associated tremor ataxia syndrome (FXTAS). Limited efforts have been made to develop new methods for improved early patient monitoring, treatment response, and disease progression. To this end, plasma metabolomic phenotyping was obtained for 23 premutation carriers and 16 age- and sex-matched controls. Three biomarkers, phenylethylamine normalized by either aconitate or isocitrate and oleamide normalized by isocitrate, exhibited excellent model performance. The lower phenylethylamine and oleamide plasma levels in carriers may indicate, respectively, incipient nigrostriatal degeneration and higher incidence of substance abuse, anxiety and sleep disturbances. Higher levels of citrate, isocitrate, aconitate, and lactate may reflect deficits in both bioenergetics and neurotransmitter metabolism (Glu, GABA). This study lays important groundwork by defining the potential utility of plasma metabolic profiling to monitor brain pathophysiology in carriers before and during the progression of FXTAS, treatment efficacy and evaluation of side effects.

Autism-Like Behavior in BTBR Mice Is Improved by Electroconvulsive Therapy

Autism is a developmental disorder characterized by impairments in social and communication abilities, as well as by restricted and repetitive behaviors. Incidence of autism is higher than earlier estimates, and treatments have limited efficacy and are costly. Limited clinical and experimental evidence suggest that patients with autism may benefit from electroconvulsive therapy (ECT). We examined the therapeutic potential of ECT in BTBR T+ tf/j mice, which represent a validated model of autism. A series of 13 electroconvulsive shocks (ECS) delivered twice a day over 7 days reversed core autism-like behavioral abnormalities-impaired sociability, social novelty, and repetitive behavior-when the animals were tested 24 h after the last ECS. The effect lasted up to 2 weeks after ECT. Neither single ECS nor a series of 6 ECS modified animals' behavior. Chronic infusion into the lateral brain ventricle of a preferential oxytocin receptor blocker (2S)-2-Amino-N-[(1S,2S,4R)-7,7-dimethyl-1-[[[4-(2-methylphenyl)-1-piperazinyl]sulfonyl]methyl]bicyclo[2.2.1]hept-2-yl]-4-(methylsulfonyl)butanamide hydrochloride abolished ECT-induced improvement of sociability and mitigated improvement of social novelty but did not affect ECT-induced reversal of repetitive behavior. These proof-of-principle experiments suggest that ECT may, indeed, be useful in the treatment of autism, and that its therapeutic effects may be mediated, in part, by central oxytocin signaling.

Gastrointestinal dysfunction in autism spectrum disorder: the role of the mitochondria and the enteric microbiome

Autism spectrum disorder (ASD) affects a significant number of individuals worldwide with the prevalence continuing to grow. It is becoming clear that a large subgroup of individuals with ASD demonstrate abnormalities in mitochondrial function as well as gastrointestinal (GI) symptoms. Interestingly, GI disturbances are common in individuals with mitochondrial disorders and have been reported to be highly prevalent in individuals with co-occurring ASD and mitochondrial disease. The majority of individuals with ASD and mitochondrial disorders do not manifest a primary genetic mutation, raising the possibility that their mitochondrial disorder is acquired or, at least, results from a combination of genetic susceptibility interacting with a wide range of environmental triggers. Mitochondria are very sensitive to both endogenous and exogenous environmental stressors such as toxicants, iatrogenic medications, immune activation, and metabolic disturbances. Many of these same environmental stressors have been associated with ASD, suggesting that the mitochondria could be the biological link between environmental stressors and neurometabolic abnormalities associated with ASD. This paper reviews the possible links between GI abnormalities, mitochondria, and ASD. First, we review the link between GI symptoms and abnormalities in mitochondrial function. Second, we review the evidence supporting the notion that environmental stressors linked to ASD can also adversely affect both mitochondria and GI function. Third, we review the evidence that enteric bacteria that are overrepresented in children with ASD, particularly Clostridia spp., produce short-chain fatty acid metabolites that are potentially toxic to the mitochondria. We provide an example of this gut–brain connection by highlighting the propionic acid rodent model of ASD and the clinical evidence that supports this animal model. Lastly, we discuss the potential therapeutic approaches that could be helpful for GI symptoms in ASD and mitochondrial disorders. To this end, this review aims to help better understand the underlying pathophysiology associated with ASD that may be related to concurrent mitochondrial and GI dysfunction.