Autism spectrum disorder in a child with propionic acidemia

Association of the Infant Gut Microbiome with Temperament at Nine Months of Age: A Michigan Cohort Study

Though studies in animals and humans link the gut microbiota to brain development and control of behavior, little research has examined this connection in healthy infants. This prospective study could determine associations between infant gut microbiota at 3 months, and infant temperament at 9 months, in a prospective pregnancy cohort (Michigan Archive for Research on Child Health; n = 159). Microbiota profiling with 16S rRNA gene sequencing was conducted on fecal samples obtained at 3 months of age. Based on the relative abundance of gut microbiotas, three groups were identified, and each group was characterized by different microbes. Infant temperament outcomes were reported by mothers using the Infant Behavior Questionnaire-Revised Very Short Form at a mean age of 9.4 months. Fully adjusted multivariate linear regression models showed that certain clusters were associated with higher negative emotionality scores, prominently among infants who had poor vitamin D intake. However, no associations were evident between gut microbiota clusters and temperament scales after FDR correction. After using three differential abundance tools, Firmicutes was associated with higher positive affect/surgency scores, whereas Clostridioides was associated with lower scores. An association between the gut microbiota and early infancy temperament was observed; thus, this study warrants replication, with a particular focus on vitamin D moderation.

The enteric metabolite, propionic acid, impairs social behavior and increases anxiety in a rodent ASD model: Examining sex differences and the influence of the estrous cycle

Research suggests that certain gut and dietary factors may worsen behavioral features of autism spectrum disorder (ASD). Treatment with propionic acid (PPA) has been found to create both brain and behavioral responses in rats that are characteristic of ASD in humans. A consistent male bias in human ASD prevalence has been observed, and several sex-differential genetic and hormonal factors have been suggested to contribute to this bias. The majority of PPA studies in relation to ASD focus on male subjects; research examining the effects of PPA in females is scarce. The present study includes two experiments. Experiment 1 explored sex differences in the effects of systemic administration of PPA (500 mg/kg, ip) on adult rodent social behavior and anxiety (light-dark test). Experiment 2 investigated differential effects of systemic administration of PPA (500 mg/kg) on social behavior and anxiety in relation to fluctuating estrogen and progesterone levels during the adult rodent estrous cycle. PPA treatment impaired social behavior and increased anxiety in females to the same degree in comparison to PPA-treated males. As well, females treated with PPA in their diestrus phase did not differ significantly in comparison to females administered PPA in their proestrus phase, in terms of reduced social behavior and increased anxiety.

Pathophysiological mechanisms of complications associated with propionic acidemia

Propionic acidemia (PA) is a genetic metabolic disorder caused by mutations in the mitochondrial enzyme, propionyl-CoA carboxylase (PCC), which is responsible for converting propionyl-CoA to methylmalonyl-CoA for further metabolism in the tricarboxylic acid cycle. When this process is disrupted, propionyl-CoA and its metabolites accumulate, leading to a variety of complications including life-threatening cardiac diseases and other metabolic strokes. While the clinical symptoms and diagnosis of PA are well established, the underlying pathophysiological mechanisms of PA-induced diseases are not fully understood. As a result, there are currently few effective therapies for PA beyond dietary restriction. This review focuses on the pathophysiological mechanisms of the various complications associated with PA, drawing on extensive research and clinical reports. Most research suggests that propionyl-CoA and its metabolites can impair mitochondrial energy metabolism and cause cellular damage by inducing oxidative stress. However, direct evidence from in vivo studies is still lacking. Additionally, elevated levels of ammonia can be toxic, although not all PA patients develop hyperammonemia. The discovery of pathophysiological mechanisms underlying various complications associated with PA can aid in the development of more effective therapeutic treatments. The consequences of elevated odd-chain fatty acids in lipid metabolism and potential gene expression changes mediated by histone propionylation also warrant further investigation.

Challenges and strategies for clinical trials in propionic and methylmalonic acidemias

Clinical trial development in rare diseases poses significant study design and methodology challenges, such as disease heterogeneity and appropriate patient selection, identification and selection of key endpoints, decisions on study duration, choice of control groups, selection of appropriate statistical analyses, and patient recruitment. Therapeutic development in organic acidemias (OAs) shares many challenges with other inborn errors of metabolism, such as incomplete understanding of natural history, heterogenous disease presentations, requirement for sensitive outcome measures and difficulties recruiting a small sample of participants. Here, we review strategies for the successful development of a clinical trial to evaluate treatment response in propionic and methylmalonic acidemias. Specifically, we discuss crucial decisions that may significantly impact success of the study, including patient selection, identification and selection of endpoints, determination of the study duration, consideration of control groups including natural history controls, and selection of appropriate statistical analyses. The significant challenges associated with designing a clinical trial in rare disease can sometimes be successfully met through strategic engagement with experts in the rare disease, seeking regulatory and biostatistical guidance, and early involvement of patients and families.

Modafinil Improves Autism-like Behavior in Rats by Reducing Neuroinflammation

To evaluate the ameliorating effect of Modafinil on neuroinflammation, behavioral, and histopathological alterations in rats induced by propionic acid (PPA). Thirty male Wistar rats were used in the study, divided into 3 groups of ten subjects. One group served as a control, the subjects in the other two were given 250 mg/kg/day of PPA by intraperitoneal injection over the course of 5 days to induce autism. The experimental design was as follows: Group 1: Normal control (orally-fed control, n = 10); Group 2 (PPA + saline, n = 10): PPA and 1 ml/kg/day % 0.9 NaCl saline via oral gavage; Group 3 (PPA + Modafinil, n = 10) PPA and 30 mg/kg/day Modafinil (Modiodal tablets 100 mg, Cephalon) via oral gavage. All of the groups were investigated for behavioral, biochemical, and histological abnormality. Autism-like behaviors were reduced significantly in the rats treated with PPA. TNF-α, Nerve Growth Factor (NGF), IL-17, IL-2, and NF-KB levels as well as MDA levels and lactate were significantly higher in those treated with PPA compared to the control group. Using immunohistochemical methods, the number of neurons and GFAP immunoreactivity was significantly altered in PPA-treated rats compared to the control. Using Magnetic Resonance Spectroscopy (MRS), we found that lactate levels were significantly higher in the PPA-treated rats, while creatinine levels were significantly decreased. In the rats administered with Modafinil, behavior, neuroinflammation, and histopathological changes brought about by PPA were significantly reversed. Our results demonstrate the potential role of Modafinil in ameliorating PPA-induced neuroinflammation in rats.

Shielding Effect of Ryanodine Receptor Modulator in Rat Model of Autism

Introduction

A neurodevelopmental disorder, autism is typically identified with three primary behavioral consequences, such as social impairment, communication problems, and limited or stereotypical behavior. Because of its co-morbidity and lack of therapeutic options, autism is a global economic burden. A short chain of fatty acid, propionic acid is formed biologically by the gut microbiome. Propionic acid levels that are too high can cause leaky intestines, which can lead to autism-like symptoms.

Methods

To induce autism, male Albino Wistar rats were given propionic acid (250 mg/kg/po on the 21st, 22nd, and 23rd postnatal days). Rats also received a ryanodine receptor antagonist (Ruthenium red: 3 mg/kg/po; postnatal 21st to 50th day) to see what influence it had on propionic acid-induced autism. Anxiety, social behavior, and repeated behaviors were all assessed, as well as oxidative stress, inflammatory indicators, neuro signaling proteins, and blood-brain barrier permeability.

Results

Ruthenium red was found to counter the propionic acid-induced increases in anxiety, repetitive behavior prefrontal cortex levels of IL-6, TNF-α, TBARS, Evans blue leakage, and water content along with decreases in social behavior, IL-10, and GSH followed by hippocampus CREB and BDNF levels.

Conclusion

Ryanodine receptor antagonists presented a neuroprotective effect in propionic acid-induced conditions like autism by modulatory effects on social and repetitive behavior, oxidative stress, neuroinflammation, and neuroprotein changes. Ryanodine receptors can be further explored in depth to manage autism as a condition.

Highlights

Ruthenium red can reduce the propionic acid-induced anxiety of rats with autism.Ruthenium red can improve the propionic acid-induced changes in repetitive behavior of rats with autism.Ruthenium red can reduce the propionic acid-induced social behavior dysfunction in rats with autism.

Plain Language Summary

Autism is a complex heterogeneous neurodevelopmental disorder mainly diagnosed with social behavior dysfunction, communication problems, and repetitive behavior. Due to high comorbidity and multiple unknown factors involvement, its exact etiology remains unclear, and so no successful treatment is available. Among the environmentally produced models of autism in rats, the most common is created by propionic acid (PPA). With short-chain type fatty acid, PPA is one of the mediators for the cycle of cell metabolism. This study attempted to study the effect of a ryano-dine receptor antagonist (Ruthenium red) on PPA-induced Anxiety, social behavior dysfunction, and repeated behaviors in rats with autism. The results showed the modulatory effects of Ruthenium red PPA-induced conditions including social and repetitive behavior, oxidative stress, neuroinflammation, and neuroprotein changes in rats with autism.

Lactobacillus plantarum PS128 prevents cognitive dysfunction in Alzheimer's disease mice by modulating propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis

Background

According to recent evidence, psychobiotics exert beneficial effects on central nervous system-related diseases, such as mental disorders. Lactobacillus plantarum PS128 (PS128), a novel psychobiotic strain, improves motor function, depression, and anxiety behaviors. However, the psychobiotic effects and mechanisms of PS128 in Alzheimer’s disease (AD) remain to be explored.

Objectives

The goal of the current study was to evaluate the beneficial effects of PS128 and to further elucidate its mechanism in AD mice.

Methods

PS128 (10¹⁰ colony-forming unit (CFU)/ml) was administered via oral gavage (o.g.) to 6-month-old male wild-type B6 and 3 × Tg-AD mice (harboring the PS1M146V, APPswe and TauP30IL transgenes) that received an intracerebroventricular injection of streptozotocin (icv-STZ, 3 mg/kg) or vehicle (saline) for 33 days. After serial behavioral tests, fecal short-chain fatty acid levels and AD-related pathology were assessed in these mice.

Results

Our findings show that intracerebroventricular injection of streptozotocin accelerated cognitive dysfunction associated with increasing levels of glycogen synthase kinase 3 beta (GSK3β) activity, tau protein phosphorylation at the T231 site (pT231), amyloid-β (Aβ) deposition, amyloid-β protein precursor (AβPP), β-site AβPP-cleaving enzyme (BACE1), gliosis, fecal propionic acid (PPA) levels and cognition-related neuronal loss and decreasing postsynaptic density protein 95 (PSD95) levels in 3 × Tg-AD mice. PS128 supplementation effectively prevented the damage induced by intracerebroventricular injection of streptozotocin in 3 × Tg-AD mice.

Conclusions

Based on the experimental results, intracerebroventricular injection of streptozotocin accelerates the progression of AD in the 3 × Tg-AD mice, primarily by increasing the levels of gliosis, which were mediated by the propionic acid and glycogen synthase kinase 3 beta pathways. PS128 supplementation prevents damage induced by intracerebroventricular injection of streptozotocin by regulating the propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis in 3 × Tg-AD mice. Therefore, we suggest that PS128 supplementation is a potential strategy to prevent and/or delay the progression of AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03426-8.

Prenatal exposure to propionic acid induces altered locomotion and reactive astrogliosis in male rats

Autism spectrum disorder (ASD) is a range of neurodevelopmental disorders characterized by movement and social deficits with rapidly increasing incidence worldwide. Propionic acid (PPA) is a histone deacetylase inhibitor that regulates neuronal plasticity in the brain. Evaluation of the behavioral and cellular consequences of PPA exposure during a critical neurodevelopmental window is required. Therefore, in the present study we aimed to evaluate the effects of prenatal PPA exposure on locomotor behavior and astrocyte number, as well as on levels of nitric oxide (NO), synaptophysin (SYP; a marker of synaptic plasticity), and metallothionein 3 (MT-III; a marker of reactive oxygen species and zinc metabolism), in the prefrontal cortex (PFC) of male rats. All parameters were evaluated at three critical ages of development: postnatal days (PD) 21 (weaning age), PD35 (pre-pubertal age) and PD70 (post-pubertal age). Prenatal PPA exposure induced hypolocomotion and decreased rearing events at weaning age. Moreover, astrogliosis in the PFC was observed in PPA-treated rats at pre- and post-pubertal age. SYP levels were dramatically decreased in PPA-treated rats with simultaneous astrogliosis, suggesting reduced synaptic plasticity. MT-III expression was deregulated in PPA-treated rats. Finally, the expression of NO in the PFC remained unaltered in PPA-treated rats. These results mimic behavioral, neuronal and astrocytic characteristics observed in ASD patients.

Valproic acid and Propionic acid modulated mechanical pathways associated with Autism Spectrum Disorder at prenatal and neonatal exposure

Autism Spectrum Disorder (ASD) is a composite disorder of brain development with uncertain etiology and pathophysiology. Genetic factors are important in ASD causation, although environmental factors are also involved in ASD pathophysiology. Environmental factors might affect the genetic processes of brain development through the modulation of molecular pathways that might be involved with ASD. Valproic acid and Propionic acid are the major environmental factors that serve as medicine and food preservative. VPA is used as an anti-epileptic medicine, but it has adverse effects on pregnant women and alters the developmental patterns of the embryo. It is a multi-targeting agent and affects through the 5-HT, GABA, etc. PPA is a secondary metabolite of gut microbiota that is commonly used as a food preservative. PPA plays a significant role in ASD causation by altering the several developmental molecular pathways like PTEN/Akt, mTOR/Gskβ, Cytokines activated pathways, etc., at the prenatal and neonatal stage. Moreover, ASD complexity might be increased by some other important factors like vitamin A deficiency and Vitamin A is important for cortical brain development and neuronal cell differentiation. Additionally, several important genes such as RELN, Lhx2, CREB, IL-6, NMDA, BDNF, etc. also altered in ASD that involved in brain development, Central Nervous System, Enteric Nervous System. These genes affect the neuronal differentiation, hyperactivity, oxidative stress, oxytocin, and GABA imbalance that lead the improper behavior in autistic individuals. These genes are also studied in VPA and PPA ASD-like animal models. In this review, we explored the mechanical pathways that might be altered with VPA and PPA exposures at the embryonic developmental stage or neonatal developmental stage.

Guidelines for the diagnosis and management of methylmalonic acidaemia and propionic acidaemia: First revision

Isolated methylmalonic acidaemia (MMA) and propionic acidaemia (PA) are rare inherited metabolic diseases. Six years ago, a detailed evaluation of the available evidence on diagnosis and management of these disorders has been published for the first time. The article received considerable attention, illustrating the importance of an expert panel to evaluate and compile recommendations to guide rare disease patient care. Since that time, a growing body of evidence on transplant outcomes in MMA and PA patients and use of precursor free amino acid mixtures allows for updates of the guidelines. In this article, we aim to incorporate this newly published knowledge and provide a revised version of the guidelines. The analysis was performed by a panel of multidisciplinary health care experts, who followed an updated guideline development methodology (GRADE). Hence, the full body of evidence up until autumn 2019 was re-evaluated, analysed and graded. As a result, 21 updated recommendations were compiled in a more concise paper with a focus on the existing evidence to enable well-informed decisions in the context of MMA and PA patient care.

Autism: Screening of inborn errors of metabolism and unexpected results

In this study, the aim was to examine patients with inborn errors of metabolism (IEM) who presented with only autism, without any other findings, to suggest any other neurological and genetic disorders. To investigate IEM, data of the hospital records of 247 patients who were referred from pediatric psychiatric to pediatric metabolism outpatient clinics due to further evaluation of autism spectrum disorders (ASD) were examined. Among them, 237 patients were evaluated for IEM leading to ASDs. Organic acidemias, phenylketonuria, tetrahydrobiopterin and neutrotransmitter disorders, biotinidase deficiency, Smith-Lemni-Opitz syndrome, disorders of cerebral creatine metabolism, urea cycle defects, homocystinuria, purine-pyrimidine metabolism disorders, mitochondrial disorders, cerebrotendinous xantomatosis, mucopolysaccaridosis, and glucose 6 phosphate dehydrogenase deficiency were screened with complete blood counts, complete biochemical analyses, homocysteine levels, an arterial blood gase, and metabolic investigations. Six patients were diagnosed as follows: one with phenylketonuria (PKU), one with cerebral creatine deficiency, one with hypobetalipoproteinemia, one with glycogen storage disease type IX-a, one with dihydropyrimidine dehydrogenase deficiency, and one with succinic semialdehyde dehydrogenase deficiency (SSADHD). Forty-six patients screened for IEM were from consanguineous families, among them, one was diagnosed with FKU and the other was with SSADHD. It would not be expected to find PKU in a 5-year-old patient as a result of newborn screening, but she could not been screened due to being a refugee. The diagnosed diseases were rare presentations of the diseases and furthermore, the diagnosis of hypobetalipoproteinemia and glycogen storage disease type IX-a were surprising with the only presentation of ASDs. LAY SUMMARY: It is well-known that some types of inborn errors of metabolism (IEM) may present with that of autism spectrum disorders (ASDs). This study suggests that in countries where consanguinity marriages are common such as Turkey and refugees whose escaped from neonatal screening are present, patients with ASD should be screened for IEMs. The results can surprise the physicians with a very rare cause of autism that has never been thought. Autism Res 2021, 14: 887-896. © 2021 International Society for Autism Research, Wiley Periodicals LLC.

Antioxidant and hepatorenal protective effects of bee pollen fractions against propionic acid-induced autistic feature in rats

In the brain, propionic acid (PA) can cross cell membranes and accumulate within cells, leading to intracellular acidification, which may alter neurotransmitter release (NT), communication between neurons, and behavior. Such elevation in levels of PA constitutes a neurodevelopmental metabolic disorder called propionic acidemia, which could clinically manifest as autism. The purpose of this study was to investigate the protective effects of different fractions of bee pollen (BP) on PA-induced autism in rats, and to evaluate their effects on the expression of liver and renal biomarkers. Groups of rats received treatments of different fractions of BP at a dose of 250 mg/kg of body weight/day for a period of 1 month. Normal control group I and group II were orally administered with phosphate-buffered saline and propionic acid, respectively, for 3 days. BP contains various health-promoting phenolic components. Different fractions of BP administered pre- and post-treatment with PA showed significant reduction in the levels of liver and renal biomarkers (p < .05). Also, a significant enhancement in the levels of glutathione S-transferase (GST), catalase CAT), and ascorbic acid (VIT C) was observed. Supplementation with BP significantly reduced biochemical changes in the liver, kidneys, and brain of rats with PA-induced toxicity. It exhibited protective effects against oxidative damage and reactive oxygen species produced by PA-induced adverse reactions in rats. Taken together, our study shows that BP possesses protective effects in PA-induced liver and kidney damage.

Gut instincts: vitamin D/vitamin D receptor and microbiome in neurodevelopment disorders

The gut microbiome regulates a relationship with the brain known as the gut–microbiota–brain (GMB) axis. This interaction is influenced by immune cells, microbial metabolites and neurotransmitters. Recent findings show gut dysbiosis is prevalent in autism spectrum disorder (ASD) as well as attention deficit hyperactivity disorder (ADHD). There are previously established negative correlations among vitamin D, vitamin D receptor (VDR) levels and severity of ASD as well as ADHD. Both vitamin D and VDR are known to regulate homeostasis in the brain and the intestinal microbiome. This review summarizes the growing relationship between vitamin D/VDR signalling and the GMB axis in ASD and ADHD. We focus on current publications and summarize the progress of GMB in neurodevelopmental disorders, describe effects and mechanisms of vitamin D/VDR in regulating the microbiome and synoptically highlight the potential applications of targeting vitamin D/VDR signalling in neurodevelopment disorders.

Involvement of tumor necrosis factor-α, interferon gamma-γ, and interleukins 1β, 6, and 10 in immunosuppression due to long-term exposure to five common food preservatives in rats

BACKGROUND/AIMS

Food preservatives are abundant in many products in the human environment. However, little is known about the impact of many food preservatives on the immune system and the immune related genes. Hence, this study aimed to evaluate the effects of five widespread food preservatives, including butylated hydroxyanisole (BHA), potassium sorbate (PS), sodium benzoate (SB), boric acid (BA), and calcium propionate (CP), on haemato-immune functions.

METHOD

Sixty Sprague-Dawley rats were assigned to groups orally administered water (control), BHA (0.09 mg/kg), PS (4.5 mg/kg), SB (0.9 mg/kg), BA (0.16 mg/kg) or CP (0.18 mg/kg) for 90 consecutive days. Leukogram and erythrogram profiles were assessed. Nitric oxide and immunoglobulin levels together with phagocytic and lysozyme activities were estimated. Histologic examinations and histomorphometric analysis of splenic tissues were performed. Variations in the mRNA expression levels of tumour necrosis factor alpha (TNF-α), interferon gamma (IFNγ), interleukin (IL)-1β, IL-6, and IL-10 were assessed.

RESULTS

Anemic conditions, thrombocytopenia, leucocytopaenia simultaneous with lymphocytopaenia, monocytopenia, and esinopenia have been obvious following long term exposure to the tested food additives. Prominent exhaustion was noted in immunoglobulin and NO levels and in lysozyme and phagocytic activities. IFNγ, TNF-α, IL-1β, IL-6, and IL-10 were obviously upregulated in the groups exposed to food preservatives.

CONCLUSION

These results confirmed that continued exposure to high levels of BHA, PS, SB, BA, and CP has haematotoxic and immunotoxic effects. Furthermore, these adverse effects are mediated by cytokine production.

Rett Syndrome, a Neurodevelopmental Disorder, Whole-Transcriptome, and Mitochondrial Genome Multiomics Analyses Identify Novel Variations and Disease Pathways

Rett syndrome (RTT) is a severe neurodevelopmental disorder reported worldwide in diverse populations. RTT is diagnosed primarily in females, with clinical findings manifesting early in life. Despite the variable rates across populations, RTT has an estimated prevalence of ∼1 in 10,000 live female births. Among 215 Saudi Arabian patients with neurodevelopmental and autism spectrum disorders, we identified 33 patients with RTT who were subsequently examined by genome-wide transcriptome and mitochondrial genome variations. To the best of our knowledge, this is the first in-depth molecular and multiomics analyses of a large cohort of Saudi RTT cases with a view to informing the underlying mechanisms of this disease that impact many patients and families worldwide. The patients were unrelated, except for 2 affected sisters, and comprised of 25 classic and eight atypical RTT cases. The cases were screened for methyl-CpG binding protein 2 (MECP2), CDKL5, FOXG1, NTNG1, and mitochondrial DNA (mtDNA) variants, as well as copy number variations (CNVs) using a genome-wide experimental strategy. We found that 15 patients (13 classic and two atypical RTT) have MECP2 mutations, 2 of which were novel variants. Two patients had novel FOXG1 and CDKL5 variants (both atypical RTT). Whole mtDNA sequencing of the patients who were MECP2 negative revealed two novel mtDNA variants in two classic RTT patients. Importantly, the whole-transcriptome analysis of our RTT patients' blood and further comparison with previous expression profiling of brain tissue from patients with RTT revealed 77 significantly dysregulated genes. The gene ontology and interaction network analysis indicated potentially critical roles of MAPK9, NDUFA5, ATR, SMARCA5, RPL23, SRSF3, and mitochondrial dysfunction, oxidative stress response and MAPK signaling pathways in the pathogenesis of RTT genes. This study expands our knowledge on RTT disease networks and pathways as well as presents novel mutations and mtDNA alterations in RTT in a population sample that was not previously studied.

Fecal Short-Chain Fatty Acids Levels Were Not Associated With Autism Spectrum Disorders in Chinese Children: A Case-Control Study

Evidence from animal models supports a link between short-chain fatty acids (SCFAs), a key subset of gut microbial metabolites, and autism spectrum disorders (ASD). However, findings from human studies on this topic are unclear. We aimed to investigate whether fecal SCFAs are associated with ASD in Chinese children aged 6–9 years old. A total of 45 ASD children aged 6–9 years and 90 sex- and age-matched neurotypical controls were enrolled. High-performance liquid chromatography was applied to quantify 10 SCFA subtypes in feces. Dietary and other socio-demographic information were obtained via face-to-face interview using questionnaires. After adjustment for multiple comparisons, paired t-test analysis indicated that the fecal total and subtype SCFA concentrations were comparable in autistic children and the controls. Conditional logistic regression analysis showed that there was no significant relationship between the fecal concentration of SCFAs and the risk of ASD after adjustment for age, sex, BMI, breastfeeding, mode of delivery, parental education level, and daily energy, protein, fat, and fiber intake. In conclusion, our results did not support the hypothesis that fecal SCFA levels might be associated with the presence of ASD. However, SCFA measurement was based on a single stool sample test, so this conclusion should be treated with caution. Further studies with measurement of long-term bodily SCFA concentrations are needed to examine this relationship.

Propionic acid induces mitochondrial dysfunction and affects gene expression for mitochondria biogenesis and neuronal differentiation in SH-SY5Y cell line

Studies in animal models have shown that the short-chain fatty acid, propionic acid (PPA), interferes with mitochondrial metabolism leading to mitochondrial dysfunction and behavioral abnormalities. The aim of this study was to investigate the effects of PPA on mitochondrial function and gene expression in neuronal cells. SH-SY5Y cells and normal human neural progenitor (NHNP) cells were exposed to 1, 5 mM PPA for 4 or 24 h and we found that the mitochondrial potential measured in SH-SY5Y cells decreased in a dose-dependent manner after PPA treatment. Electron microscopy analysis revealed that the size of the mitochondria was significantly reduced following PPA treatment. A dose-dependent increase in the mitochondrial DNA copy number was observed in the PPA-treated cells. The expression of the mitochondrial biogenesis-related proteins PGC-1α, TFAM, SIRT3, and COX4 was significantly increased after PPA treatment. Transcriptome analysis revealed that mRNA expression in the notch signaling-related genes ASCL1 and LFNG changed after PPA treatment and the positive correlated protein expression changes were also observed. These results revealed that PPA treatment may affect neurodevelopment by altering mitochondrial function and notch signaling-related gene expression.

Pathophysiology of propionic and methylmalonic acidemias. Part 1: Complications

Over the last decades, advances in clinical care for patients suffering from propionic acidemia (PA) and isolated methylmalonic acidemia (MMA) have resulted in improved survival. These advances were possible thanks to new pathophysiological insights. However, patients may still suffer from devastating complications which largely determine the unsatisfying overall outcome. To optimize our treatment strategies, better insight in the pathophysiology of complications is needed. Here, we perform a systematic data-analysis of cohort studies and case-reports on PA and MMA. For each of the prevalent and rare complications, we summarize the current hypotheses and evidence for the underlying pathophysiology of that complication. A common hypothesis on pathophysiology of many of these complications is that mitochondrial impairment plays a major role. Assuming that complications in which mitochondrial impairment may play a role are overrepresented in monogenic mitochondrial diseases and, conversely, that complications in which mitochondrial impairment does not play a role are underrepresented in mitochondrial disease, we studied the occurrence of the complications in PA and MMA in mitochondrial and other monogenic diseases, using data provided by the Human Phenotype Ontology. Lastly, we combined this with evidence from literature to draw conclusions on the possible role of mitochondrial impairment in each complication. Altogether, this review provides a comprehensive overview on what we, to date, do and do not understand about pathophysiology of complications occurring in PA and MMA and about the role of mitochondrial impairment herein.

Autism Spectrum Disorder and Associated Risk Factors: A Matched Case-Control Study

Background and aims: Despite substantial advances in the etiology of autism spectrum disorder (ASD), the environmental risk factors have not yet been well understood. The present study investigated the association between ASD, and maternal and perinatal risk factors. Methods: This matched, case-control study was conducted in Hamadan, the west of Iran, from November 2015 to May 2016. We enrolled 41 children with ASD aged 3-17 years. We selected four controls per one case from the same hospital where patients were born. Controls were separately matched with cases for sex, age, and birth year. Results: We compared 41 ASD cases with 164 controls. After adjusting the odds ratio (95% CI), ASD was significantly associated with third-degree relatives consanguinity [3.29 (1.39, 7.75)], short birth length [4.99 (1.15, 21.60)], short head circumference [7.87 (1.48, 41.76), respiratory distress syndrome at birth 3.97 (1.91, 8.22)], respiratory assistance at birth [2.92 (1.39, 6.10)], birth hypoxia [2.85 (1.35, 5.99)], and low 1-minute Apgar score [3.65 (1.04, 12.75)]. Conclusions: Our findings suggest that ASD may be associated with multiple maternal and perinatal risk factors. Evidence based on large prospective multicenter cohort studies is required to indicate the impacts of maternal and perinatal exposures.

Spectrum of mutations underlying Propionic acidemia and further insight into a genotype-phenotype correlation for the common mutation in Saudi Arabia

Propionic acidemia (PA) is an autosomal recessive metabolic disorder. PA is characterized by deficiency of the mitochondrial enzyme propionyl CoA carboxylase (PCC) that results in the accumulation of propionic acid. Alpha and beta subunits of the PCC enzyme are encoded by the PCCA and PCCB genes, respectively. Pathogenic variants in PCCA or PCCB disrupt the function of the PCC enzyme preventing the proper breakdown of certain amino acids and metabolites. To determine the frequency of pathogenic variants in PA in our population, 84 Saudi Arabian patients affected with PA were sequenced for both the PCCA and PCCB genes. We found that variants in PCCA accounted for 81% of our cohort (68 patients), while variants in PCCB only accounted for 19% (16 patients). In total, sixteen different sequence variants were detected in the study, where 7 were found in PCCA and 9 in PCCB. The pathogenic variant (c.425G > A; p.Gly142Asp) in PCCA is the most common cause of PA in our cohort and was found in 59 families (70.2%), followed by the frameshift variant (c.990dupT; p.E331Xfs*1) in PCCB that was found in 7 families (8.3%). The p.Gly142Asp missense variant is likely to be a founder pathogenic variant in patients of Saudi Arabian tribal origin and is associated with a severe phenotype. All variants were inherited in a homozygous state except for one family who was compound heterozygous. A total of 11 novel pathogenic variants were detected in this study thereby increasing the known spectrum of pathogenic variants in the PCCA and PCCB genes.

Selective modulator of peroxisome proliferator-activated receptor-α protects propionic acid induced autism-like phenotypes in rats

AIMS

The present study investigated the neuropharmacological role of PPAR-α modulator, fenofibrate in postnatal-propionic acid induced symptomatology related with autism spectrum disorders (ASD) in Wistar rats.

MAIN METHODS

The propionic acid (250 mg/kg, p.o.) was administered to rats from postnatal 21st day to 23rd day to induce autism-related neurobehavioral and neurobiochemical alterations in rats. Then, rats were treated with fenofibrate (100 mg/kg and 200 mg/kg, orally) from postnatal 24th day till 48th day. The social behavior (three chambers social testing apparatus), repetitive behavior (Y-maze), locomotor activity (actophotometer), anxiety (elevated plus maze) and exploratory behavior (hole board test) were assessed. Biochemically, oxidative stress (thiobarbituric acid reactive species and reduced glutathione level) and neuroinflammation (interleukin-6, tumor necrosis factor-α and interleukin-10) were evaluated in the cerebellum, brainstem and prefrontal cortex of rats.

KEY FINDINGS

Propionic acid-treated rats showed social impairment, repetitive behavior, hyperlocomotion, anxiety and low exploratory activity. Also, these animals showed higher levels of oxidative stress (increased in thiobarbituric acid reactive species and decreased in reduced glutathione level) as well as inflammation (increased in interleukin-6, tumor necrosis factor-α and decreased in interleukin-10) and inflammation in aforementioned brain-regions. Treatment with fenofibrate significantly attenuated the propionic acid induced-social impairment, repetitive behavior, hyperactivity, anxiety and low exploratory activity. Furthermore, fenofibrate also reduced the oxidative stress and neuroinflammation in propionic acid-treated rats.

SIGNIFICANCE

A selective PPAR-α agonist, fenofibrate provides neurobehavioral and neurobiochemical benefits in postnatal-propionic acid induced autism-related phenotype in rats. Thus, fenofibrate may further be studied for its possible benefits in ASD symptoms.

Autism spectrum disorders in propionic acidemia patients

Propionic acidemia is the result of a deficiency in propionyl-CoA carboxylase activity. Chronic neurologic and cognitive complications frequently occur, but the psychiatric evolution of the disorder is not well documented. We conducted a pedopsychiatric evaluation of 19 children, adolescents and young adults, aged between 2 and 25 years, using ADI-R, CARS-T, as well as ADOS when autism spectrum disorder was suspected. Previous psychometric examinations were also taken into consideration. Thirteen patients had an IQ < 80. Two patients presented with autism and two additional patients with other autism spectrum disorders. Five patients did not fulfill diagnostic criteria for autism spectrum disorder but showed difficulties indicative of a broader autism phenotype (BAP). Four other patients had severe anxiety manifestations related to their disease. Two patients presented with acute psychotic episodes. The number of decompensations in the first 3 years of life was lower in patients with autism spectrum disorder or related symptoms. These patients were also older when they were assessed (median age of 15 years old versus 11 years old). There was no significant correlation between 3-hydroxypropionate levels during the first 6 years of life and autism spectrum disorder diagnosis. In conclusion, autism spectrum disorder is frequent in patients with propionic acidemia. These patients should undergo in-depth psychiatric evaluation and be screened for autism spectrum disorder. Further studies are needed to understand the underlying mechanisms.

Dietary Considerations in Autism Spectrum Disorders: The Potential Role of Protein Digestion and Microbial Putrefaction in the Gut-Brain Axis

Children with autism spectrum disorders (ASD), characterized by a range of behavioral abnormalities and social deficits, display high incidence of gastrointestinal (GI) co-morbidities including chronic constipation and diarrhea. Research is now increasingly able to characterize the “fragile gut” in these children and understand the role that impairment of specific GI functions plays in the GI symptoms associated with ASD. This mechanistic understanding is extending to the interactions between diet and ASD, including food structure and protein digestive capacity in exacerbating autistic symptoms. Children with ASD and gut co-morbidities exhibit low digestive enzyme activity, impaired gut barrier integrity and the presence of antibodies specific for dietary proteins in the peripheral circulation. These findings support the hypothesis that entry of dietary peptides from the gut lumen into the vasculature are associated with an aberrant immune response. Furthermore, a subset of children with ASD exhibit high concentrations of metabolites originating from microbial activity on proteinaceous substrates. Taken together, the combination of specific protein intakes poor digestion, gut barrier integrity, microbiota composition and function all on a background of ASD represents a phenotypic pattern. A potential consequence of this pattern of conditions is that the fragile gut of some children with ASD is at risk for GI symptoms that may be amenable to improvement with specific dietary changes. There is growing evidence that shows an association between gut dysfunction and dysbiosis and ASD symptoms. It is therefore urgent to perform more experimental and clinical research on the “fragile gut” in children with ASD in order to move toward advancements in clinical practice. Identifying those factors that are of clinical value will provide an evidence-based path to individual management and targeted solutions; from real time sensing to the design of diets with personalized protein source/processing, all to improve GI function in children with ASD.

Antipurinergic therapy for autism-An in-depth review

Are the symptoms of autism caused by a treatable metabolic syndrome that traces to the abnormal persistence of a normal, alternative functional state of mitochondria? A small clinical trial published in 2017 suggests this is possible. Based on a new unifying theory of pathogenesis for autism called the cell danger response (CDR) hypothesis, this study of 10 boys, ages 5-14years, showed that all 5 boys who received antipurinergic therapy (APT) with a single intravenous dose of suramin experienced improvements in all the core symptoms of autism that lasted for 5-8weeks. Language, social interaction, restricted interests, and repetitive movements all improved. Two children who were non-verbal spoke their first sentences. None of these improvements were observed in the placebo group. Larger and longer studies are needed to confirm this promising discovery. This review introduces the concept of M2 (anti-inflammatory) and M1 (pro-inflammatory) mitochondria that are polarized along a functional continuum according to cell stress. The pathophysiology of the CDR, the complementary functions of M1 and M2 mitochondria, relevant gene-environment interactions, and the metabolic underpinnings of behavior are discussed as foundation stones for understanding the improvements in ASD behaviors produced by antipurinergic therapy in this small clinical trial.

Audit of Organic Acidurias from a Single Centre: Clinical and Metabolic Profile at Presentation with Long Term Outcome

Introduction

Organic Acidurias (OA) accounts between 10% and 40% of confirmed Inborn Errors of Metabolism (IEM) in India. With prompt recognition and management, better survival but adverse neurodevelopmental outcome is reported.

Aim

To study the clinical and metabolic presentation, management with immediate and long term outcome of symptomatic children with confirmed OA.

Materials and Methods

Hospital based study of symptomatic children diagnosed to have OA between 2003 and 2009 and the survivors followed up over next five years. Diagnosis was based on clinical and metabolic presentation and confirmed by spectrometry analyses of urine and blood. Management, immediate outcome, compliance to treatment and recurrence of crises were documented. Neurodevelopmental outcome was assessed in follow up. Mean with Standard Error (Mean ± SE) and frequencies with percentages were calculated.

Results

Of 72 cases suspected to have IEM, 38 (52.8%) were confirmed of (IEM), and out of which 15 (39.5%) had OA. Methyl malonic acidemia, multiple carboxylase deficiency and Propionic Acidemia (PA) constituted the largest proportion. Neurodevelopmental issues (73.3%) and metabolic crisis (53.3%) were common presenting features. Mean ± SE of ammonia was 639.0±424.1 μg/dl and lactate was 33.6±4.9 mg/dl. Mean pH, bicarbonate, and anion gap was 7.27±0.07, 14.1±2.3 and 17.9±2.3 respectively. Management was protocol based. Death was reported in two cases of PA; other morbidities were seen in five. Recurrent crisis (46.7%) complicated the follow up in survivors. Spasticity, extrapyramidal movement disorder, intellectual subnormality, autism spectrum, attention deficit hyperactivity disorder and sensory neural deafness were seen amongst survivors, in spite of compliance to therapy.

Conclusion

OA is part of differential diagnosis in sick children and treatment needs to be prompt and specific. Prognosis is guarded even with long term cofactor supplementation in the symptomatic.

Fast and simple method for semiquantitative determination of calcium propionate in bread samples

Calcium propionate has been widely used as a preservative in bakery and in bread. It is sometimes not carefully used, or a high concentration is added to preserve products. High consumption of calcium propionate can lead to several health problems. This study aims to develop a fast and simple semiquantitative method based on color complex formation for the determination of calcium propionate in a bread sample. A red–brown complex was obtained from the reaction of ferric ammonium sulfate and propionate anion. The product was rapidly formed and easily observed with the concentration of propionate anion >0.4 mg/mL. A high-performance liquid chromatography (HPLC) method was also developed and validated for comparison. Twenty-two bread samples from three markets near Bangkok were randomly selected and assayed for calcium propionate using the above two developed methods. The results showed that 19/22 samples contained calcium propionate > 2000 mg/kg. The results of the complex formation method agreed with the HPLC method.

Can psychiatric childhood disorders be due to inborn errors of metabolism?

Many patients who visit a centre for hereditary metabolic diseases remarkably also suffer from a child psychiatric disorder. Those child psychiatric disorders may be the first sign or manifestation of an underlying metabolic disorder. Lack of knowledge of metabolic disorders in child psychiatry may lead to diagnoses being missed. Patients therefore are also at risk for not accessing efficacious treatment and proper counselling. To search the literature for the co-occurrence of child psychiatric disorders, such as ADHD, autism, psychosis, learning disorders and eating disorders and metabolic disorders. A search of the literature was conducted by performing a broad search on PubMed, using the terms "ADHD and metabolic disorders", "autism and metabolic disorders", "psychosis and metabolic disorders", "learning disorders and metabolic disorders", and "eating disorders and metabolic disorders". Based on inclusion criteria (concerning a clear psychiatric disorder and concerning a metabolic disorder) 4441 titles and 249 abstracts were screened and resulted in 71 relevant articles. This thorough literature search provides child and adolescent psychiatrists with an overview of metabolic disorders associated with child psychiatric symptoms, their main characteristics and recommendations for further investigations.

Propionic acid metabolism, ASD, and vitamin B12: Is there a role for environmental nitrous oxide?

Foley et al. (2014) published their findings in this journal on the role of prenatal exposure to propionic acid (PPA) and behavioral outcomes in treated rat pups. The authors show that PPA treated pups displayed subtle differences in behavior including nest seeking, novel object recognition, and locomotor activity. Others have previously proposed that PPA infusion in rat could represent a valid animal model of ASD since many of the diagnostic criteria for the disorder spectrum manifest under such conditions. A pathogenic makeover of gut microbiome to facilitate the growth of microbes capable of producing PPA, like Clostridia species, has been proposed as an infectious contributing etiology to the PPA model of ASD, however the reason for this pathogenic microbial overgrowth is not clear. This discussion highlights a previously identified novel environmental factor (i.e., nitrous oxide, N₂O) in the etiopathogenesis of ASD and related neuropathology and posits that altered PPA metabolism in ASD may represent a key manifestation of this particular exposure. Trace environmental exposure to N₂O may induce release of endogenous opioid peptides that have been shown to confer a virulence advantage to certain microbes, like Pseudomonas aeruginosa. Pathogenic overproduction of PPA in ASD may be a compensatory mechanism to curb this enhanced virulence potential. Therefore, future research on the PPA model of ASD should consider its role as a consequence of environmental exposure to N₂O.

Autism in patients with propionic acidemia

Certain inborn errors of metabolism have been suggested to increase the risk of autistic behavior. In an animal model, propionic acid ingestion triggered abnormal behavior resembling autism. So far only a few cases were reported with propionic acidemia and autistic features. From a series of twelve consecutively diagnosed cases with propionic acidemia, we report on eight patients with autistic features. The patients were followed 2-4 times a year and underwent regular clinical, dietary and laboratory investigations. Psychological evaluation was performed every second to fourth year. All patients were compliant with the standard diet and carnitine supplementation. None of the patients had frequent metabolic decompensations. From the metabolic factors known to impact neuropsychological outcome we detected chronically decreased valine levels and altered valine to leucine ratios in five out of the eight patients. Recurrent lactic acid elevations were present in six out of the eight patients. Five of the eight patients were diagnosed with Autism Spectrum Disorder, four of them had pathogenic variants in PCCB. Disorder according to DSM-IV and/or DSM-5 criteria. One of the patients diagnosed with propionic acidemia by newborn screening had the most significant behavioral features and another was diagnosed with Autism Spectrum Disorder prior to propionic acidemia. We hypothesize that chronic suboptimal intracellular metabolic balance may be responsible for the increased risk for autistic features in propionic acidemia. We propose that patients diagnosed with propionic acidemia should be screened for Autism Spectrum Disorder.

Gastrointestinal symptoms and autism spectrum disorder: links and risks - a possible new overlap syndrome

Autism spectrum disorder (ASD) is a genetically determined neurodevelopmental brain disorder presenting with restricted, repetitive patterns of behaviors, interests, and activities, or persistent deficits in social communication and social interaction. ASD is characterized by many different clinical endophenotypes and is potentially linked with certain comorbidities. According to current recommendations, children with ASD are at risk of having alimentary tract disorders - mainly, they are at a greater risk of general gastrointestinal (GI) concerns, constipation, diarrhea, and abdominal pain. GI symptoms may overlap with ASD core symptoms through different mechanisms. These mechanisms include multilevel pathways in the gut-brain axis contributing to alterations in behavior and cognition. Shared pathogenetic factors and pathophysiological mechanisms possibly linking ASD and GI disturbances, as shown by most recent studies, include intestinal inflammation with or without autoimmunity, immunoglobulin E-mediated and/or cell-mediated GI food allergies as well as gluten-related disorders (celiac disease, wheat allergy, non-celiac gluten sensitivity), visceral hypersensitivity linked with functional abdominal pain, and dysautonomia linked with GI dysmotility and gastroesophageal reflux. Dysregulation of the gut microbiome has also been shown to be involved in modulating GI functions with the ability to affect intestinal permeability, mucosal immune function, and intestinal motility and sensitivity. Metabolic activity of the microbiome and dietary components are currently suspected to be associated with alterations in behavior and cognition also in patients with other neurodegenerative diseases. All the above-listed GI factors may contribute to brain dysfunction and neuroinflammation depending upon an individual patient's genetic vulnerability. Due to a possible clinical endophenotype presenting as comorbidity of ASD and GI disorders, we propose treating this situation as an "overlap syndrome". Practical use of the concept of an overlap syndrome of ASD and GI disorders may help in identifying those children with ASD who suffer from an alimentary tract disease. Unexplained worsening of nonverbal behaviors (agitation, anxiety, aggression, self-injury, sleep deprivation) should alert professionals about this possibility. This may shorten the time to diagnosis and treatment commencement, and thereby alleviate both GI and ASD symptoms through reducing pain, stress, or discomfort. Furthermore, this may also protect children against unnecessary dietary experiments and restrictions that have no medical indications. A personalized approach to each patient is necessary. Our understanding of ASDs has come a long way, but further studies and more systematic research are warranted.

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.

Propionic acidemia in the Arab World

The autosomal recessive disease propionic acidemia (PA) is an inborn error of metabolism with highly variable clinical manifestations, caused by a deficiency of propionyl-CoA carboxylase (PCC) enzyme, due to mutations in either PCCA or PCCB genes, which encode the alpha and beta subunits of the PCC enzyme, respectively. The classical clinical presentation consists of poor feeding, vomiting, metabolic acidosis, hyperammonemia, lethargy, neurological problems, and developmental delay. PA seems to be a prevalent disease in the Arab World. Arab patients with PA seem to have the same classical clinical picture for PA with distinctive associated complications and other diseases. Most of the mutations found in Arab patients seem to be specific to the Arab population, and not observed in other ethnic groups. In this review, I will discuss in details the clinical and molecular profile of Arab patients with PA.

Antipurinergic therapy corrects the autism-like features in the Fragile X (Fmr1 knockout) mouse model

Background

This study was designed to test a new approach to drug treatment of autism spectrum disorders (ASDs) in the Fragile X (Fmr1) knockout mouse model.

Methods

We used behavioral analysis, mass spectrometry, metabolomics, electron microscopy, and western analysis to test the hypothesis that the disturbances in social behavior, novelty preference, metabolism, and synapse structure are treatable with antipurinergic therapy (APT).

Results

Weekly treatment with the purinergic antagonist suramin (20 mg/kg intraperitoneally), started at 9 weeks of age, restored normal social behavior, and improved metabolism, and brain synaptosomal structure. Abnormalities in synaptosomal glutamate, endocannabinoid, purinergic, and IP3 receptor expression, complement C1q, TDP43, and amyloid β precursor protein (APP) were corrected. Comprehensive metabolomic analysis identified 20 biochemical pathways associated with symptom improvements. Seventeen pathways were shared with human ASD, and 11 were shared with the maternal immune activation (MIA) model of ASD. These metabolic pathways were previously identified as functionally related mediators of the evolutionarily conserved cell danger response (CDR).

Conclusions

The data show that antipurinergic therapy improves the multisystem, ASD-like features of both the environmental MIA, and the genetic Fragile X models. These abnormalities appeared to be traceable to mitochondria and regulated by purinergic signaling.

Electronic supplementary material

The online version of this article (doi:10.1186/2040-2392-6-1) contains supplementary material, which is available to authorized users.

Acute psychosis in propionic acidemia: 2 case reports

Propionic acidemia is an inborn deficiency of propionyl-coenzyme A (CoA) carboxylase activity, which leads to mitochondrial accumulation of propionyl-CoA and its by-products. Neurologic complications are frequent, but only a few cases presenting with psychiatric symptoms have been reported so far. We report 2 cases of children with chronic psychiatric symptoms who presented with an acute psychotic episode as teenagers. Both patients had hallucinations, panic and grossly disorganized behavior, for several weeks to several months. They had signs of moderate metabolic decompensation at the beginning of the episode, although the psychiatric symptoms lasted longer than the metabolic imbalance. We propose that these episodes were at least partially imputable to propionic acidemia. Such episodes require psychiatric examination and antipsychotic treatment, which may have to be adapted in case of cardiomyopathy or long QT syndrome.

Pre- and neonatal exposure to lipopolysaccharide or the enteric metabolite, propionic acid, alters development and behavior in adolescent rats in a sexually dimorphic manner

Alterations in the composition of the gut microbiome and/or immune system function may have a role in the development of autism spectrum disorders (ASD). The current study examined the effects of prenatal and early life administration of lipopolysaccharide (LPS), a bacterial mimetic, and the short chain fatty acid, propionic acid (PPA), a metabolic fermentation product of enteric bacteria, on developmental milestones, locomotor activity, and anxiety-like behavior in adolescent male and female offspring. Pregnant Long-Evans rats were subcutaneously injected once a day with PPA (500 mg/kg) on gestation days G12–16, LPS (50 µg/kg) on G15–16, or vehicle control on G12–16 or G15–16. Male and female offspring were injected with PPA (500 mg/kg) or vehicle twice a day, every second day from postnatal days (P) 10–18. Physical milestones and reflexes were monitored in early life with prenatal PPA and LPS inducing delays in eye opening. Locomotor activity and anxiety were assessed in adolescence (P40–42) in the elevated plus maze (EPM) and open-field. Prenatal and postnatal treatments altered behavior in a sex-specific manner. Prenatal PPA decreased time spent in the centre of the open-field in males and females while prenatal and postnatal PPA increased anxiety behavior on the EPM in female rats. Prenatal LPS did not significantly influence those behaviors. Evidence for the double hit hypothesis was seen as females receiving a double hit of PPA (prenatal and postnatal) displayed increased repetitive behavior in the open-field. These results provide evidence for the hypothesis that by-products of enteric bacteria metabolism such as PPA may contribute to ASD, altering development and behavior in adolescent rats similar to that observed in ASD and other neurodevelopmental disorders.

Autism spectrum disorders and inborn errors of metabolism: an update

BACKGROUND

Autism spectrum disorder is characterized by social communicative deficits with restricted interests occurring in about 1% of the population. Although its exact cause is not known, several factors have been implicated in its etiology, including inborn errors of metabolism. Although relatively uncommon, these disorders frequently occur in countries with high rates of consanguinity and are often associated with behavioral problems, such as hyperactivity and aggression. The aim of this review is to examine the association of autism with these conditions.

METHOD

A computer-assisted search was performed to identify the most common inborn errors of metabolism associated with autism.

RESULTS

The following disorders were identified: phenylketonuria, glucose-6-phosphatase deficiency, propionic acidemia, adenosine deaminase deficiency, Smith-Lemli-Opitz syndrome and mitochondrial disorders, and the recently described branched chain ketoacid dehydrogenase kinase deficiency.

CONCLUSION

The risk of autistic features is increased in children with inborn errors of metabolism, especially in the presence of cognitive and behavioral deficits. We propose that affected children should be screened for autism.

A review of traditional and novel treatments for seizures in autism spectrum disorder: findings from a systematic review and expert panel

Despite the fact that seizures are commonly associated with autism spectrum disorder (ASD), the effectiveness of treatments for seizures has not been well studied in individuals with ASD. This manuscript reviews both traditional and novel treatments for seizures associated with ASD. Studies were selected by systematically searching major electronic databases and by a panel of experts that treat ASD individuals. Only a few anti-epileptic drugs (AEDs) have undergone carefully controlled trials in ASD, but these trials examined outcomes other than seizures. Several lines of evidence point to valproate, lamotrigine, and levetiracetam as the most effective and tolerable AEDs for individuals with ASD. Limited evidence supports the use of traditional non-AED treatments, such as the ketogenic and modified Atkins diet, multiple subpial transections, immunomodulation, and neurofeedback treatments. Although specific treatments may be more appropriate for specific genetic and metabolic syndromes associated with ASD and seizures, there are few studies which have documented the effectiveness of treatments for seizures for specific syndromes. Limited evidence supports l-carnitine, multivitamins, and N-acetyl-l-cysteine in mitochondrial disease and dysfunction, folinic acid in cerebral folate abnormalities and early treatment with vigabatrin in tuberous sclerosis complex. Finally, there is limited evidence for a number of novel treatments, particularly magnesium with pyridoxine, omega-3 fatty acids, the gluten-free casein-free diet, and low-frequency repetitive transcranial magnetic simulation. Zinc and l-carnosine are potential novel treatments supported by basic research but not clinical studies. This review demonstrates the wide variety of treatments used to treat seizures in individuals with ASD as well as the striking lack of clinical trials performed to support the use of these treatments. Additional studies concerning these treatments for controlling seizures in individuals with ASD are warranted.

Unique acyl-carnitine profiles are potential biomarkers for acquired mitochondrial disease in autism spectrum disorder

Autism spectrum disorder (ASD) has been associated with mitochondrial disease (MD). Interestingly, most individuals with ASD and MD do not have a specific genetic mutation to explain the MD, raising the possibility of that MD may be acquired, at least in a subgroup of children with ASD. Acquired MD has been demonstrated in a rodent ASD model in which propionic acid (PPA), an enteric bacterial fermentation product of ASD-associated gut bacteria, is infused intracerebroventricularly. This animal model shows validity as it demonstrates many behavioral, metabolic, neuropathologic and neurophysiologic abnormalities associated with ASD. This animal model also demonstrates a unique pattern of elevations in short-chain and long-chain acyl-carnitines suggesting abnormalities in fatty-acid metabolism. To determine if the same pattern of biomarkers of abnormal fatty-acid metabolism are present in children with ASD, the laboratory results from a large cohort of children with ASD (n=213) who underwent screening for metabolic disorders, including mitochondrial and fatty-acid oxidation disorders, in a medically based autism clinic were reviewed. Acyl-carnitine panels were determined to be abnormal if three or more individual acyl-carnitine species were abnormal in the panel and these abnormalities were verified by repeated testing. Overall, 17% of individuals with ASD demonstrated consistently abnormal acyl-carnitine panels. Next, it was determined if specific acyl-carnitine species were consistently elevated across the individuals with consistently abnormal acyl-carnitine panels. Significant elevations in short-chain and long-chain, but not medium-chain, acyl-carnitines were found in the ASD individuals with consistently abnormal acyl-carnitine panels-a pattern consistent with the PPA rodent ASD model. Examination of electron transport chain function in muscle and fibroblast culture, histological and electron microscopy examination of muscle and other biomarkers of mitochondrial metabolism revealed a pattern consistent with the notion that PPA could be interfering with mitochondrial metabolism at the level of the tricarboxylic-acid cycle (TCAC). The function of the fatty-acid oxidation pathway in fibroblast cultures and biomarkers for abnormalities in non-mitochondrial fatty-acid metabolism were not consistently abnormal across the subgroup of ASD children, consistent with the notion that the abnormalities in fatty-acid metabolism found in this subgroup of children with ASD were secondary to TCAC abnormalities. Glutathione metabolism was abnormal in the subset of ASD individuals with consistent acyl-carnitine panel abnormalities in a pattern similar to glutathione abnormalities found in the PPA rodent model of ASD. These data suggest that there are similar pathological processes between a subset of ASD children and an animal model of ASD with acquired mitochondrial dysfunction. Future studies need to identify additional parallels between the PPA rodent model of ASD and this subset of ASD individuals with this unique pattern of acyl-carnitine abnormalities. A better understanding of this animal model and subset of children with ASD should lead to better insight in mechanisms behind environmentally induced ASD pathophysiology and should provide guidance for developing preventive and symptomatic treatments.