Zinc in gut-brain interaction in autism and neurological disorders

The Role of the Gut Microbiome in the Associations Between Lead Exposure and Child Neurodevelopment

Lead is highly toxic to the developing brain. Given its persistence in the environment, new intervention strategies are needed to mitigate the impacts of lead on child neurodevelopment. The gut microbiome, referring to the bacteria and microorganisms residing in the gastrointestinal system, may be a viable target for intervention. This short review summarizes recent evidence linking the gut-brain axis to child developmental outcomes. We explore how lead-induced effects to the gut microbiome could indirectly affect child neurodevelopment, such that disrupting or offsetting this mediating process could buffer the effects of lead on child developmental outcomes. Unexpected findings with respect to child microbiota diversity and child cognitive and behavioral outcomes as well as lead exposure and adult microbiota diversity are discussed. When possible, we draw connections between observed changes to relative bacterial abundance, proposed bacterial functions, and downstream effects to brain development. We also explore how the gut microbiome might modify the toxicity of lead by impeding the uptake of lead across the gastrointestinal tract or through indirect mechanisms in such ways that the gut microbiome does not fit within a mediating pathway. In this case, promoting the buffering capacity of the gut microbiome may reduce the impacts of lead on child neurodevelopment. The goal of this short review is to bring attention to the potential roles of the gut microbiome in the associations between lead exposure and child neurodevelopment with an eye towards intervention.

Correlations Between Gut Microbiota Composition, Medical Nutrition Therapy, and Insulin Resistance in Pregnancy-A Narrative Review

Many physiological changes accompany pregnancy, most of them involving metabolic perturbations. Alterations in microbiota composition occur both before and during pregnancy and have recently been correlated with an important role in the development of metabolic complications, such as insulin resistance and gestational diabetes mellitus (GDM). These changes may be influenced by physiological adaptations to pregnancy itself, as well as by dietary modifications during gestation. Medical nutritional therapy (MNT) applied to pregnant women at risk stands out as one of the most important factors in increasing the microbiota's diversity at both the species and genus levels. In this review, we discuss the physiological changes during pregnancy and their impact on the composition of the intestinal microbiota, which may contribute to GDM. We also discuss findings from previous studies regarding the effectiveness of MNT in reducing insulin resistance. In the future, additional studies should aim to identify specific gut microbial profiles that serve as early indicators of insulin resistance during gestation. Early diagnosis, achievable through stool analysis or metabolite profiling, may facilitate the timely implementation of dietary or pharmaceutical modifications, thereby mitigating the development of insulin resistance and its associated sequelae.

Nutritional management and autism spectrum disorder: A systematic review

BACKGROUND

Autism spectrum disorder (ASD) presents unique challenges related to feeding and nutritional management. Children with ASD often experience feeding difficulties, including food selectivity, refusal, and gastrointestinal issues. Various interventions have been explored to address these challenges, including dietary modifications, vitamin supplementation, feeding therapy, and behavioral interventions.

AIM

To provide a comprehensive overview of the current evidence on nutritional management in ASD. We examine the effectiveness of dietary interventions, vitamin supplements, feeding therapy, behavioral interventions, and mealtime practices in addressing the feeding challenges and nutritional needs of children with ASD.

METHODS

We systematically searched relevant literature up to June 2024, using databases such as PubMed, PsycINFO, and Scopus. Studies were included if they investigated dietary interventions, nutritional supplements, or behavioral strategies to improve feeding behaviors in children with ASD. We assessed the quality of the studies and synthesized findings on the impact of various interventions on feeding difficulties and nutritional outcomes. Data extraction focused on intervention types, study designs, participant characteristics, outcomes measured, and intervention effectiveness.

RESULTS

The review identified 316 studies that met the inclusion criteria. The evidence indicates that while dietary interventions and nutritional supplements may offer benefits in managing specific symptoms or deficiencies, the effectiveness of these approaches varies. Feeding therapy and behavioral interventions, including gradual exposure and positive reinforcement, promise to improve food acceptance and mealtime behaviors. The findings also highlight the importance of creating supportive mealtime environments tailored to the sensory and behavioral needs of children with ASD.

CONCLUSION

Nutritional management for children with ASD requires a multifaceted approach that includes dietary modifications, supplementation, feeding therapy, and behavioral strategies. The review underscores the need for personalized interventions and further research to refine treatment protocols and improve outcomes. Collaborative efforts among healthcare providers, educators, and families are essential to optimize this population's nutritional health and feeding practices. Enhancing our understanding of intervention sustainability and long-term outcomes is essential for optimizing care and improving the quality of life for children with ASD and their families.

Exploring potential mechanisms for zinc deficiency to impact in autism spectrum disorder: a narrative review

Autism spectrum disorder (ASD) is a heterogeneous and complex group of life-long neurodevelopmental disorders. How this clinical condition impacts an individual's intellectual, social and emotional capacities, contributing to alterations in the proprioceptive and sensory systems and increasing their selective attitude towards food, is well described in the literature. This complex condition or status exposes individuals with ASD to an increased risk of developing overweight, obesity and non-communicable diseases compared with the neurotypical population. Moreover, individuals with ASD are characterised by higher levels of inflammation, oxidative stress markers and intestinal dysbiosis. All these clinical features may also appear in zinc deficiency (ZD) condition. In fact, zinc is an essential micronutrient for human health, serving as a structural, catalytic and regulatory component in numerous physiological processes. The aim of this narrative review is to explore role of ZD in ASD. Factors affecting zinc absorption, excretion and dietary intake in this vulnerable population are taken into consideration. Starting from this manuscript, the authors encourage future research to investigate the role of ZD in ASD. The perspective is to potentially find another missing piece in the 'ASD clinical puzzle picture' to improve the health status of these individuals.

Immune Remodeling during Aging and the Clinical Significance of Immunonutrition in Healthy Aging

Aging is associated with changes in the immune system and the gut microbiota. Immunosenescence may lead to a low-grade, sterile chronic inflammation in a multifactorial and dynamic way, which plays a critical role in most age-related diseases. Age-related changes in the gut microbiota also shape the immune and inflammatory responses. Nutrition is a determinant of immune function and of the gut microbiota. Immunonutrion has been regarded as a new strategy for disease prevention and management, including many age-related diseases. However, the understanding of the cause-effect relationship is required to be more certain about the role of immunonutrition in supporting the immune homeostasis and its clinical relevance in elderly individuals. Herein, we review the remarkable quantitative and qualitative changes during aging that contribute to immunosenescence, inflammaging and microbial dysbiosis, and the effects on late-life health conditions. Furthermore, we discuss the clinical significance of immunonutrition in the treatment of age-related diseases by systematically reviewing its modulation of the immune system and the gut microbiota to clarify the effect of immunonutrition-based interventions on the healthy aging.

Nutritional epigenetics education improves diet and attitude of parents of children with autism or attention deficit/hyperactivity disorder

BACKGROUND

Unhealthy maternal diet leads to heavy metal exposures from the consumption of ultra-processed foods that may impact gene behavior across generations, creating conditions for the neurodevelopmental disorders known as autism and attention deficit/hyperactivity disorder (ADHD). Children with these disorders have difficulty metabolizing and excreting heavy metals from their bloodstream, and the severity of their symptoms correlates with the heavy metal levels measured in their blood. Psychiatrists may play a key role in helping parents reduce their ultra-processed food and dietary heavy metal intake by providing access to effective nutritional epigenetics education.

AIM

To test the efficacy of nutritional epigenetics instruction in reducing parental ultra-processed food intake.

METHODS

The study utilized a semi-randomized test and control group pretest-posttest pilot study design with participants recruited from parents having a learning-disabled child with autism or ADHD. Twenty-two parents who met the inclusion criteria were randomly selected to serve in the test (n = 11) or control (n = 11) group. The test group participated in the six-week online nutritional epigenetics tutorial, while the control group did not. The efficacy of the nutritional epigenetics instruction was determined by measuring changes in parent diet and attitude using data derived from an online diet survey administered to the participants during the pre and post intervention periods. Diet intake scores were derived for both ultra-processed and whole/organic foods. Paired sample t-tests were conducted to determine any differences in mean diet scores within each group.

RESULTS

There was a significant difference in the diet scores of the test group between the pre- and post-intervention periods. The parents in the test group significantly reduced their intake of ultra-processed foods with a pre-intervention diet score of 70 (mean = 5.385, SD = 2.534) and a post-intervention diet score of 113 (mean = 8.692, SD = 1.750) and the paired t-test analysis showing a significance of P < 0.001. The test group also significantly increased their consumption of whole and/or organic foods with a pre-intervention diet score of 100 (mean = 5.882, SD = 2.472) and post-intervention diet score of 121 (mean = 7.118, SD = 2.390) and the paired t-test analysis showing a significance of P < 0.05.

CONCLUSION

Here we show nutritional epigenetics education can be used to reduce ultra-processed food intake and improve attitude among parents having learning-disabled children with autism or ADHD.

The enteric nervous system deficits in autism spectrum disorder

Gastrointestinal (GI) disorders are common comorbidities in individuals with autism spectrum disorder (ASD), and abnormalities in these issues have been found to be closely related to the severity of core behavioral deficits in autism. The enteric nervous system (ENS) plays a crucial role in regulating various aspects of gut functions, including gastrointestinal motility. Dysfunctional wiring in the ENS not only results in various gastrointestinal issues, but also correlates with an increasing number of central nervous system (CNS) disorders, such as ASD. However, it remains unclear whether the gastrointestinal dysfunctions are a consequence of ASD or if they directly contribute to its pathogenesis. This review focuses on the deficits in the ENS associated with ASD, and highlights several high-risk genes for ASD, which are expressed widely in the gut and implicated in gastrointestinal dysfunction among both animal models and human patients with ASD. Furthermore, we provide a brief overview of environmental factors associated with gastrointestinal tract in individuals with autism. This could offer fresh perspectives on our understanding of ASD.

Zinc Status and Autism Spectrum Disorder in Children and Adolescents: A Systematic Review

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder, the prevalence of which has increased in children and adolescents over the years. Studies point to deficiency of trace elements as one of the factors involved in the etiology of the disorder, with zinc being one of the main trace elements investigated in individuals with ASD. The aim of this review is to summarize scientific evidence about the relationship between zinc status and ASD in children and adolescents. This review has been registered in the International Prospective Register of Systematic Reviews (registration number CRD42020157907). The methodological guidelines adopted were in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were selected from an active investigation of the PubMed, Scopus, LILACS, and Google databases to search for observational studies. Fifty-two studies from twenty-two countries were included. The sample sizes ranged from 20 to 2635, and the participants ranged from 2 to 18 years old. Nine types of biological matrices were used, with hair, serum, and plasma being the most frequently used in the evaluation of zinc concentrations. Significant differences in zinc concentrations between the ASD and control groups were observed in 23 studies, of which 19 (36%) showed lower zinc concentrations in the ASD group. The classification of studies according to methodological quality resulted in high, moderate, and low quality in 10, 21, and 21 studies, respectively. In general, we did not observe a significant difference between zinc concentrations of children and adolescents with ASD compared to controls; however, studies point to an occurrence of lower concentrations of Zn in individuals with ASD. This review reveals that more prospective studies with greater methodological rigor should be conducted in order to further characterize this relation.

Micronutrient Research in Autism Spectrum Disorder. A Clinical Study

Autistic spectrum disorders are part of the category of neurodevelopmental disorders, characterized by: difficulties in communication and social interaction, restrictive and repetitive patterns of behaviours and activities, which are present throughout the developmental period, and can be diagnosed in the first five years of life. Due to the increase in the incidence of this disorder in recent years, it has become a topic of great interest both to specialists in child and adolescent psychiatry and to researchers in the field. Given the polymorphism of Autism Spectrum Disorder and the need to discover factors that better explain the etiology of this disorder, studies related to biomarkers are extremely varied. One of the areas of study that have exercised particular interest is related to the involvement of metals in the pathology of autism spectrum disorder. Apart from the controversies related to heavy metals that according to studies affect the developmental process, there are studies that suggest that some micronutrients such as zinc, copper, selenium, iron, magnesium, may be involved in the etiology of autism spectrum disorder. Starting from these studies, we set out to investigate to what extent these essential metals for the body are involved in the etiology of autism spectrum disorder and how they influence the severity of symptoms.

Total Reflection X-ray Fluorescence Analysis of Plasma Elements in Autistic Children from India

Trace elements are essential for the human body's various physiological processes but if they are present in higher concentration, these elements turn to be toxic and cause adverse effect on physiological processes. Similarly, deficiency of these essential elements also affects physiological processes and leads to abnormal metabolic activities. There is a lot of interest in recent years to know the mystery behind the involvement of trace elements in the metabolic activities of autistic children suspecting that it may be a risk factor in the aetiology of autism. The present study aims to analyse the plasma trace elements in autistic children using the total reflection X-ray fluorescence (TXRF) technique. Plasma samples from 70 autistic children (mean age: 11.5 ± 3.1) were analysed with 70 age- and sex-matched healthy children as controls (mean age: 12 ± 2.5). TXRF analysis revealed the higher concentration of copper (1227.8 ± 17.8), chromium (7.1 ± 2.5), bromine (2695.1 ± 24) and arsenic (126.3 ± 10) and lower concentration of potassium (440.1 ± 25), iron (1039.6 ± 28), zinc (635.7 ± 21), selenium (52.3 ± 8.5), rubidium (1528.9 ± 28) and molybdenum (162,800.8 ± 14) elements in the plasma of autistic children in comparison to healthy controls. Findings of the first study from India suggest these altered concentrations in elements in autistic children over normal healthy children affect the physiological processes and metabolism. Further studies are needed to clarify the association between the altered element concentration and physiology of autism in the North Karnataka population in India.

MOLECULAR MECHANISMS DEFINING APPLICATION OF GLYCINE AND ZINC COMBINATIONIN CORRECTION OF STRESS AND ANXIETY MAIN MANIFESTATIONS

The aim of the work was to carry out a systematic analysis of the molecular mechanisms that determine the possibility of a combined use of amino acid glycine and zinc compounds for the treatment of patients with manifestations of stress and anxiety.

Materials and methods. Information retrieval (Scopus, PubMed) and library (eLibrary) databases were used as research tools. In some cases, the ResearchGate application was applied for a semantic search. The analysis and generalization of references was carried out on the research topic, covering the period from 2000 to the present time.

Results. It has been shown that amino acid glycine, along with gamma-aminobutyric acid (GABA), is a key neurotransmitter that regulates physiological inhibition processes in the central nervous system (CNS) by increasing transmembrane conductance in specific pentameric ligand-gated ion channels. The introduction of zinc ions can potentiate the opening of these receptors by increasing their affinity for glycine, resulting in an inhibitory processes increase in CNS neurons. The replenishment of the glycine and zinc combined deficiency is an important element in the correction of a post-stress dysfunction of the central nervous system. A balanced intake of zinc and glycine is essential for most people who experience daily effects of multiple stresses and anxiety. This combination is especially useful for the people experiencing a state of chronic psycho-emotional stress and maladaptation, including those who have a difficulty in falling asleep.

Conclusion. A balanced maintenance of the zinc and glycine concentration in the body of a healthy person leads to the development of a stable anti-anxiety effect, which is accompanied by the normalization of the sleep-wake rhythm, which makes it possible to have a good rest without any loss of working efficiency after waking up.

Associations of essential element serum concentrations with autism spectrum disorder

This case-control study explored the associations between autism spectrum disorder (ASD) and the serum concentration of nine chemical elements in children. The study recruited 92 Chinese children with ASD and 103 typically developing individuals. Serum concentrations of nine chemical elements (calcium, iodine, iron, lithium, magnesium, potassium, selenium, strontium, and zinc) were determined by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). An unconditional logistic regression model was used to analyze the associations between the serum concentrations of the elements and the risk of ASD. After adjusting for confounders, the multivariate analysis results showed that zinc ≤ 837.70 ng/mL, potassium > 170.06 μg/mL, and strontium ≤ 52.46 ng/mL were associated with an increased risk of ASD, while selenium > 159.80 ng/mL was associated with a decreased risk of ASD. Furthermore, the degree of lithium and zinc deficiency was associated with ASD severity. The results indicated that metallomic profiles of some specific elements might play important roles in the development of ASD, a finding of scientific significance for understanding the etiology, and providing dietary guidance for certain ASD types.

Prevalence of low dietary zinc intake in women and pregnant women in Ireland

Background

In humans, zinc is involved in many biological functions acting as signaling ion, neurotransmitter, structural component of proteins, and cofactor for many enzymes and, through this, is an important regulator of the immune and nervous system. Food supplies zinc to the human body, but a high prevalence of inadequate dietary zinc intake has been reported worldwide.

Aims

The objective of this study was to investigate the zinc intake and bioavailability of over 250 women (pregnant and non-pregnant) based in Ireland, in order to evaluate the dietary inadequacy of zinc.

Methodology

We used a food frequency questionnaire designed to assess the zinc intake and bioavailability of the participants.

Results

Our results show that 58% of participants are at risk of inadequate zinc intake and that 29% may be zinc deficient. The prevalence of inadequate zinc intake was lower for pregnant women (zinc deficient 9%, at risk 38%) than for non-pregnant women due to more frequent consumption of supplements. Low zinc intake was not correlated with the age of participants and resulted from a combination of inadequate intake of zinc-rich food and relatively higher intake of food items rich in phytate, a major zinc uptake inhibitor.

Conclusions

We conclude that at present, low zinc intake may be prevalent in as much as 87% of women, including 47% of pregnant women. Therefore, zinc status needs to be considered as a factor impacting the health of women, and in particular pregnant women, also in industrialized and developed countries such as Ireland.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11845-022-03181-w.

Alteration in Gut Microbiota Associated with Zinc Deficiency in School-Age Children

Zinc deficiency could lead to a dynamic variation in gut microbial composition and function in animals. However, how zinc deficiency affects the gut microbiome in school-age children remains unclear. The purpose of this study was to profile the dynamic shifts in the gut microbiome of school-age children with zinc deficiency, and to determine whether such shifts are associated with dietary intake. A dietary survey, anthropometric measurements, and serum tests were performed on 177 school-age children, and 67 children were selected to explore the gut microbial community using amplicon sequencing. School-age children suffered from poor dietary diversity and insufficient food and nutrient intake, and 32% of them were zinc deficient. The inflammatory cytokines significantly increased in the zinc deficiency (ZD) group compared to that in the control (CK) group (p < 0.05). There was no difference in beta diversity, while the Shannon index was much higher in the ZD group (p < 0.05). At the genus level, Coprobacter, Acetivibrio, Paraprevotella, and Clostridium_XI were more abundant in the ZD group (p < 0.05). A functional predictive analysis showed that the metabolism of xenobiotics by cytochrome P450 was significantly depleted in the ZD group (p < 0.05). In conclusion, gut microbial diversity was affected by zinc deficiency with some specific bacteria highlighted in the ZD group, which may be used as biomarkers for further clinical diagnosis of zinc deficiency.

The Impact of Zinc and Zinc Homeostasis on the Intestinal Mucosal Barrier and Intestinal Diseases

Zinc is an essential trace element for living organisms, and zinc homeostasis is essential for the maintenance of the normal physiological functions of cells and organisms. The intestine is the main location for zinc absorption and excretion, while zinc and zinc homeostasis is also of great significance to the structure and function of the intestinal mucosal barrier. Zinc excess or deficiency and zinc homeostatic imbalance are all associated with many intestinal diseases, such as IBD (inflammatory bowel disease), IBS (irritable bowel syndrome), and CRC (colorectal cancer). In this review, we describe the role of zinc and zinc homeostasis in the intestinal mucosal barrier and the relevance of zinc homeostasis to gastrointestinal diseases.

Impact of Zinc Transport Mechanisms on Embryonic and Brain Development

The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.

Prenatal Zinc Deficient Mice as a Model for Autism Spectrum Disorders

Epidemiological studies have shown a clear association between early life zinc deficiency and Autism Spectrum Disorders (ASD). In line with this, mouse models have revealed prenatal zinc deficiency as a profound risk factor for neurobiological and behavioral abnormalities in the offspring reminiscent of ASD behavior. From these studies, a complex pathology emerges, with alterations in the gastrointestinal and immune system and synaptic signaling in the brain, as a major consequence of prenatal zinc deficiency. The features represent a critical link in a causal chain that leads to various neuronal dysfunctions and behavioral phenotypes observed in prenatal zinc deficient (PZD) mice and probably other mouse models for ASD. Given that the complete phenotype of PZD mice may be key to understanding how non-genetic factors can modify the clinical features and severity of autistic patients and explain the observed heterogeneity, here, we summarize published data on PZD mice. We critically review the emerging evidence that prenatal zinc deficiency is at the core of several environmental risk factors associated with ASD, being mechanistically linked to ASD-associated genetic factors. In addition, we highlight future directions and outstanding questions, including potential symptomatic, disease-modifying, and preventive treatment strategies.

Dietary zinc supplementation rescues fear-based learning and synaptic function in the Tbr1+/- mouse model of autism spectrum disorders

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by a dyad of behavioural symptoms-social and communication deficits and repetitive behaviours. Multiple aetiological genetic and environmental factors have been identified as causing or increasing the likelihood of ASD, including serum zinc deficiency. Our previous studies revealed that dietary zinc supplementation can normalise impaired social behaviours, excessive grooming, and heightened anxiety in a Shank3 mouse model of ASD, as well as the amelioration of synapse dysfunction. Here, we have examined the efficacy and breadth of dietary zinc supplementation as an effective therapeutic strategy utilising a non-Shank-related mouse model of ASD-mice with Tbr1 haploinsufficiency.

METHODS

We performed behavioural assays, amygdalar slice whole-cell patch-clamp electrophysiology, and immunohistochemistry to characterise the synaptic mechanisms underlying the ASD-associated behavioural deficits observed in Tbr1+/- mice and the therapeutic potential of dietary zinc supplementation. Two-way analysis of variance (ANOVA) with Šídák's post hoc test and one-way ANOVA with Tukey's post hoc multiple comparisons were performed for statistical analysis.

RESULTS

Our data show that dietary zinc supplementation prevents impairments in auditory fear memory and social interaction, but not social novelty, in the Tbr1+/- mice. Tbr1 haploinsufficiency did not induce excessive grooming nor elevate anxiety in mice. At the synaptic level, dietary zinc supplementation reversed α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and N-methyl-D-aspartate receptor (NMDAR) hypofunction and normalised presynaptic function at thalamic-lateral amygdala (LA) synapses that are crucial for auditory fear memory. In addition, the zinc supplemented diet significantly restored the synaptic puncta density of the GluN1 subunit essential for functional NMDARs as well as SHANK3 expression in both the basal and lateral amygdala (BLA) of Tbr1+/- mice.

LIMITATIONS

The therapeutic effect of dietary zinc supplementation observed in rodent models may not reproduce the same effects in human patients. The effect of dietary zinc supplementation on synaptic function in other brain structures affected by Tbr1 haploinsufficiency including olfactory bulb and anterior commissure will also need to be examined.

CONCLUSIONS

Our data further the understanding of the molecular mechanisms underlying the effect of dietary zinc supplementation and verify the efficacy and breadth of its application as a potential treatment strategy for ASD.

Lack of Vesicular Zinc Does Not Affect the Behavioral Phenotype of Polyinosinic:Polycytidylic Acid-Induced Maternal Immune Activation Mice

Zinc is important in neural and synaptic development and neuronal transmission. Within the brain, zinc transporter 3 (ZnT3) is essential for zinc uptake into vesicles. Loss of vesicular zinc has been shown to produce neurodevelopmental disorder (NDD)-like behavior, such as decreased social interaction and increased anxiety- and repetitive-like behavior. Maternal immune activation (MIA) has been identified as an environmental factor for NDDs, such as autism spectrum disorders (ASDs) and schizophrenia (SZ), in offspring, which occurs during pregnancy when the mother’s immune system reacts to the exposure to viruses or infectious diseases. In this study, we investigated the interaction effect of a genetic factor [ZnT3 knockout (KO) mice] and an environmental factor (MIA). We induced MIA in pregnant female (dams) mice during mid-gestation, using polyinosinic:polycytidylic acid (polyI:C), which mimics a viral infection. Male and female ZnT3 KO and wild-type (WT) offspring were tested in five behavioral paradigms: Ultrasonic Vocalizations (USVs) at postnatal day 9 (P9), Open Field Test, Marble Burying Test, three-Chamber Social Test, and Pre-pulse Inhibition (PPI) in adulthood (P60–75). Our results indicate that loss of vesicular zinc does not result in enhanced ASD- and SZ-like phenotype compared to WT, nor does it show a more pronounced phenotype in male ZnT3 KO compared to female ZnT3 KO. Finally, MIA offspring demonstrated an ASD- and SZ-like phenotype only in specific behavioral tests: increased calls emitted in USVs and fewer marbles buried. Our results suggest that there is no interaction between the loss of vesicular zinc and MIA induction in the susceptibility to developing an ASD- and SZ-like phenotype.

The Role of Copper and Zinc in Irritable Bowel Syndrome: A Mendelian Randomization Study

Irritable bowel syndrome (IBS) has been associated with copper and zinc imbalance and a zinc-deficient diet. Mendelian randomization was used in this study to evaluate if genetically determined copper and zinc levels play a causal role in the development of IBS. Three single-nucleotide polymorphisms (SNPs; rs1175550, rs2769264, and rs2769270) associated with erythrocyte copper levels, and 3 SNPs associated with erythrocyte zinc levels (rs11638477, rs1532423, and rs2120019) in the Australian Twin Study (1993-1996 and 2001-2005) were used as instrumental variables for levels of these metals. The association of these SNPs with IBS was tested using summary statistics computed from data on 340,331 individuals from the UK Biobank, 5,548 of whom had IBS (2006-2010). Genetically predicted high serum copper levels were associated with a lower risk of IBS (odds ratio = 0.89; 95% confidence interval: 0.80, 0.98). Genetically predicted, high serum zinc levels were nonsignificantly associated with a higher risk of IBS (odds ratio = 1.06; 95% confidence interval: 0.95, 1.18). Sensitivity analysis did not suggest the presence of pleiotropy. These results suggest that high erythrocyte copper levels may be protective against IBS development. Targeting higher levels, therefore, may provide an avenue to reduce the likelihood of IBS development in high-risk individuals.

Zinc is a key regulator of gastrointestinal development, microbiota composition and inflammation with relevance for autism spectrum disorders

Gastrointestinal (GI) problems and microbiota alterations have been frequently reported in autism spectrum disorders (ASD). In addition, abnormal perinatal trace metal levels have been found in ASD. Accordingly, mice exposed to prenatal zinc deficiency display features of ASD-like behavior. Here, we model GI development using 3D intestinal organoids grown under zinc-restricted conditions. We found significant morphological alterations. Using proteomic approaches, we identified biological processes affected by zinc deficiency that regulate barrier permeability and pro-inflammatory pathways. We confirmed our results in vivo through proteomics studies and investigating GI development in zinc-deficient mice. These show altered GI physiology and pro-inflammatory signaling, resulting in chronic systemic and neuroinflammation, and gut microbiota composition similar to that reported in human ASD cases. Thus, low zinc status during development is sufficient to compromise intestinal barrier integrity and activate pro-inflammatory signaling, resulting in changes in microbiota composition that may aggravate inflammation, altogether mimicking the co-morbidities frequently observed in ASD.

Comparative effect of potentiated zinc oxide and antibiotic growth promoters on intestinal morphometry and nutrient digestibility in broiler chickens

The comparative effects of potentiated zinc oxide (pZnO) and antibiotic growth promoters (AGP) supplementation on intestinal morphometry and nutrient digestibility in broiler chickens were studied. Four hundred straight-run Cobb 500-day-old broiler chicks were randomly allotted to four dietary treatments replicated 10 times with 10 birds per replicate. Dietary treatments were as follows: T1: basal diets without AGP (negative control; NC), T2: basal diets with 500 g/t maduramicin 10 g and 500 g/t zinc bacitracin 150 (positive control; PC), T3: NC added with 150 g/t pZnO, and T4: PC added with 150 g/t pZnO in a 2 × 2 factorial design in RCBD. At days 18 and 35, 10 birds were randomly selected per treatment for morphometry of the duodenum, jejunum, and ileum. At day 38, eight birds per treatment were used for the nutrient digestibility study. Results showed significant interaction effects (P < 0.05) of AGP and pZnO supplementation on day 35 intestinal morphometry of duodenum's villi height and villi height: crypt depth, and ileum's crypt depth; apparent COD_GE, AME, CP, DM, and EE. Significant differences (P < 0.05) with pZnO supplementation were only observed on feed intake and FCR of birds fed with pZnO at days 8-14 and fecal quality at days 0-7. Results of present study suggested that pZnO has the potential to replace AGPs without negatively affecting the intestinal morphometry, digestibility, and growth performance of broiler chickens.

Gut Microbiota as a Mediator of Essential and Toxic Effects of Zinc in the Intestines and Other Tissues

The objective of the present study was to review the existing data on the association between Zn status and characteristics of gut microbiota in various organisms and the potential role of Zn-induced microbiota in modulating systemic effects. The existing data demonstrate a tight relationship between Zn metabolism and gut microbiota as demonstrated in Zn deficiency, supplementation, and toxicity studies. Generally, Zn was found to be a significant factor for gut bacteria biodiversity. The effects of physiological and nutritional Zn doses also result in improved gut wall integrity, thus contributing to reduced translocation of bacteria and gut microbiome metabolites into the systemic circulation. In contrast, Zn overexposure induced substantial alterations in gut microbiota. In parallel with intestinal effects, systemic effects of Zn-induced gut microbiota modulation may include systemic inflammation and acute pancreatitis, autism spectrum disorder and attention deficit hyperactivity disorder, as well as fetal alcohol syndrome and obesity. In view of both Zn and gut microbiota, as well as their interaction in the regulation of the physiological functions of the host organism, addressing these targets through the use of Zn-enriched probiotics may be considered an effective strategy for health management.

Potential importance of supplementation with zinc for autism spectrum disorder

Zinc is an essential micronutrient for cellular proliferation and subsequent body and brain development. Zinc deficiency is becoming a major public health issue equally in under-developed and developed countries. The lack of sufficient zinc, whether related to environmental or internal factors, is an important environmental stressor that is eligible to become elucidated as a contributing factor for the pathogenesis of autism spectrum disorder (ASD). The aim of this manuscript is to briefly overview available data regarding the relationship of zinc deficiency with the development of ASD and to relate these data with currently known pathogenetic mechanisms of this disorder namely brain growth disturbances and neuropeptides secretion. Zinc deficiency impacts brain connectivity and growth and alters adequate neurotransmission. In addition, zinc deficiency may indirectly act on the brain by disturbing the immune system and by altering the normal gut-brain connection. Zinc seems to be important for the social effect of neuropeptides. Zinc supplementation in pregnant women and newborn children with the aim of preventing ASD needs further consideration.

S100B dysregulation during brain development affects synaptic SHANK protein networks via alteration of zinc homeostasis

Autism Spectrum Disorders (ASD) are caused by a combination of genetic predisposition and nongenetic factors. Among the nongenetic factors, maternal immune system activation and zinc deficiency have been proposed. Intriguingly, as a genetic factor, copy-number variations in S100B, a pro-inflammatory damage-associated molecular pattern (DAMP), have been associated with ASD, and increased serum S100B has been found in ASD. Interestingly, it has been shown that increased S100B levels affect zinc homeostasis in vitro. Thus, here, we investigated the influence of increased S100B levels in vitro and in vivo during pregnancy in mice regarding zinc availability, the zinc-sensitive SHANK protein networks associated with ASD, and behavioral outcomes. We observed that S100B affects the synaptic SHANK2 and SHANK3 levels in a zinc-dependent manner, especially early in neuronal development. Animals exposed to high S100B levels in utero similarly show reduced levels of free zinc and SHANK2 in the brain. On the behavioral level, these mice display hyperactivity, increased stereotypic and abnormal social behaviors, and cognitive impairment. Pro-inflammatory factors and zinc-signaling alterations converge on the synaptic level revealing a common pathomechanism that may mechanistically explain a large share of ASD cases.

Zinc status in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis of observational studies

Previous studies regarding the zinc status in attention-deficit/hyperactivity disorder (ADHD) yielded inconsistent results. Thus, the present meta-analysis was aimed to estimate the association between hair and serum/plasma zinc levels and ADHD. Online databases of Medline, EMBASE, and Scopus were searched up to October 2020 with no limitation in time and language. Weighted mean differences (WMDs) of hair and serum/plasma zinc levels were calculated using a random-effects model. Overall, 22 articles with 1280 subjects with ADHD and 1200 controls were included. The pooled effect size indicated that serum/plasma zinc levels in subjects with ADHD were not statistically different than their controls (WMD = − 1.26 µmol/L; 95% CI − 3.72, 1.20). Interestingly, the exclusion of one study from the analysis showed that people with ADHD significantly have lower circulating levels of zinc compared to their controls (WMD: − 2.49 µmol/L; 95% CI − 4.29, − 0.69). Also, the pooled effect size indicated that hair zinc levels in cases with ADHD were not statistically different than their controls (WMD = − 24.19 μg/g; 95% CI − 61.80, 13.42). Present meta-analysis raises the possibility that subjects with ADHD are prone to have declined levels of zinc levels. Based on current findings, screening the zinc levels in subjects with ADHD could be reasonable. Further well-designed studies are needed to clarify the role of zinc in the etiology of ADHD.

The Metallome as a Link Between the "Omes" in Autism Spectrum Disorders

Metal dyshomeostasis plays a significant role in various neurological diseases such as Alzheimer's disease, Parkinson's disease, Autism Spectrum Disorders (ASD), and many more. Like studies investigating the proteome, transcriptome, epigenome, microbiome, etc., for years, metallomics studies have focused on data from their domain, i.e., trace metal composition, only. Still, few have considered the links between other "omes," which may together result in an individual's specific pathologies. In particular, ASD have been reported to have multitudes of possible causal effects. Metallomics data focusing on metal deficiencies and dyshomeostasis can be linked to functions of metalloenzymes, metal transporters, and transcription factors, thus affecting the proteome and transcriptome. Furthermore, recent studies in ASD have emphasized the gut-brain axis, with alterations in the microbiome being linked to changes in the metabolome and inflammatory processes. However, the microbiome and other "omes" are heavily influenced by the metallome. Thus, here, we will summarize the known implications of a changed metallome for other "omes" in the body in the context of "omics" studies in ASD. We will highlight possible connections and propose a model that may explain the so far independently reported pathologies in ASD.

Zinc

Since the discovery of manifest Zn deficiency in 1961, the increasing number of studies demonstrated the association between altered Zn status and multiple diseases. In this chapter, we provide a review of the most recent advances on the role of Zn in health and disease (2010-20), with a special focus on the role of Zn in neurodegenerative and neurodevelopmental disorders, diabetes and obesity, male and female reproduction, as well as COVID-19. In parallel with the revealed tight association between ASD risk and severity and Zn status, the particular mechanisms linking Zn2+ and ASD pathogenesis like modulation of synaptic plasticity through ProSAP/Shank scaffold, neurotransmitter metabolism, and gut microbiota, have been elucidated. The increasing body of data indicate the potential involvement of Zn2+ metabolism in neurodegeneration. Systemic Zn levels in Alzheimer's and Parkinson's disease were found to be reduced, whereas its sequestration in brain may result in modulation of amyloid β and α-synuclein processing with subsequent toxic effects. Zn2+ was shown to possess adipotropic effects through the role of zinc transporters, zinc finger proteins, and Zn-α2-glycoprotein in adipose tissue physiology, underlying its particular role in pathogenesis of obesity and diabetes mellitus type 2. Recent findings also contribute to further understanding of the role of Zn2+ in spermatogenesis and sperm functioning, as well as oocyte development and fertilization. Finally, Zn2+ was shown to be the potential adjuvant therapy in management of novel coronavirus infection (COVID-19), underlining the perspectives of zinc in management of old and new threats.

In Pursuit of Healthy Aging: Effects of Nutrition on Brain Function

Consuming a balanced, nutritious diet is important for maintaining health, especially as individuals age. Several studies suggest that consuming a diet rich in antioxidants and anti-inflammatory components such as those found in fruits, nuts, vegetables, and fish may reduce age-related cognitive decline and the risk of developing various neurodegenerative diseases. Numerous studies have been published over the last decade focusing on nutrition and how this impacts health. The main objective of the current article is to review the data linking the role of diet and nutrition with aging and age-related cognitive decline. Specifically, we discuss the roles of micronutrients and macronutrients and provide an overview of how the gut microbiota-gut-brain axis and nutrition impact brain function in general and cognitive processes in particular during aging. We propose that dietary interventions designed to optimize the levels of macro and micronutrients and maximize the functioning of the microbiota-gut-brain axis can be of therapeutic value for improving cognitive functioning, particularly during aging.

Role of zinc in neonatal growth and brain growth: review and scoping review

This manuscript includes (1) a narrative review of Zinc as an essential nutrient for fetal and neonatal growth and brain growth and development and (2) a scoping review of studies assessing the effects of Zinc supplementation on survival, growth, brain growth, and neurodevelopment in neonates. Very preterm infants and small for gestational age infants are at risk for Zinc deficiency. Zinc deficiency can cause several complications including periorificial lesions, delayed wound healing, hair loss, diarrhea, immune deficiency, growth failure with stunting, and brain atrophy and dysfunction. Zinc is considered essential for oligodendrogenesis, neurogenesis, neuronal differentiation, white matter growth, and multiple biological and physiological roles in neurobiology. Data support the possibility that the critical period of Zinc delivery for brain growth in the mouse starts at 18 days of a 20-21-day pregnancy and extends during lactation and in human may start at 26 weeks of gestation and extend until at least 44 weeks of postmenstrual age. Studies are needed to better elucidate Zinc requirement in extremely low gestational age neonates to minimize morbidity, optimize growth, and brain growth, prevent periventricular leukomalacia and optimize neurodevelopment. IMPACT: Zinc is essential for growth and brain growth and development. In the USA, very preterm small for gestational age infants are at risk for Zinc deficiency. Data support the possibility that the critical period of Zinc delivery for brain growth in the mouse starts at 18 days of a 20-21-day pregnancy and extends during lactation and in human may start at 26 weeks' gestation and extend until at least 44 weeks of postmenstrual age. Several randomized trials of Zinc supplementation in neonates have shown improvement in growth when using high enough dose, for long duration in patients likely to or proven to have a Zinc deficiency. Studies are needed to better elucidate Zinc requirement in extremely low gestational age neonates to minimize morbidity, optimize growth and brain growth, prevent periventricular leukomalacia and optimize neurodevelopment.

Most Effective Combination of Nutraceuticals for Improved Memory and Cognitive Performance in the House Cricket, Acheta domesticus

Background: Dietary intake of multivitamins, zinc, polyphenols, omega fatty acids, and probiotics have all shown benefits in learning, spatial memory, and cognitive function. It is important to determine the most effective combination of antioxidants and/or probiotics because regular ingestion of all nutraceuticals may not be practical. This study examined various combinations of nutrients to determine which may best enhance spatial memory and cognitive performance in the house cricket (Acheta domesticus (L.)). Methods: Based on the 31 possible combinations of multivitamins, zinc, polyphenols, omega-3 polyunsaturated fatty acids (PUFAs), and probiotics, 128 house crickets were divided into one control group and 31 experimental groups with four house crickets in each group. Over eight weeks, crickets were fed their respective nutrients, and an Alternation Test and Recognition Memory Test were conducted every week using a Y-maze to test spatial working memory. Results: The highest-scoring diets shared by both tests were the combination of multivitamins, zinc, and omega-3 fatty acids (VitZncPuf; Alternation: slope = 0.07226, Recognition Memory: slope = 0.07001), the combination of probiotics, polyphenols, multivitamins, zinc, and omega-3 PUFAs (ProPolVitZncPuf; Alternation: slope = 0.07182, Recognition Memory: slope = 0.07001), the combination of probiotics, multivitamins, zinc, and omega-3 PUFAs (ProVitZncPuf; Alternation: slope = 0.06999, Recognition Memory: slope = 0.07001), and the combination of polyphenols, multivitamins, zinc, and omega-3 PUFAs (PolVitZncPuf; Alternation: slope = 0.06873, Recognition Memory: slope = 0.06956). Conclusion: All of the nutrient combinations demonstrated a benefit over the control diet, but the most significant improvement compared to the control was found in the VitZncPuf, ProVitZncPuf, PolVitZncPuf, and ProPolVitZncPuf. Since this study found no significant difference between the performance and improvement of subjects within these four groups, the combination of multivitamins, zinc, and omega-3 fatty acids (VitZncPuf) was concluded to be the most effective option for improving memory and cognitive performance.

Beyond the Mind-Serum Trace Element Levels in Schizophrenic Patients: A Systematic Review

The alterations in serum trace element levels are common phenomena observed in patients with different psychiatric conditions such as schizophrenia, autism spectrum disorder, or major depressive disorder. The fluctuations in the trace element concentrations might act as potential diagnostic and prognostic biomarkers of many psychiatric and neurological disorders. This paper aimed to assess the alterations in serum trace element concentrations in patients with a diagnosed schizophrenia. The authors made a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 5009 articles identified through database searching, 59 of them were assessed for eligibility. Ultimately, 33 articles were included in the qualitative synthesis. This review includes the analysis of serum levels of the following trace elements: iron, nickel, molybdenum, phosphorus, lead, chromium, antimony, uranium, magnesium, aluminum, zinc, copper, selenium, calcium, and manganese. Currently, there is no consistency regarding serum trace element levels in schizophrenic patients. Thus, it cannot be considered as a reliable prognostic or diagnostic marker of schizophrenia. However, it can be assumed that altered concentrations of those elements are crucial regarding the onset and exaggeration of either psychotic or negative symptoms or cognitive dysfunctions.

Abnormal Levels of Metal Micronutrients and Autism Spectrum Disorder: A Perspective Review

The aim of the present review is to summarize the prevalence of abnormal levels of various metal micronutrients including copper (Cu), iron (Fe), magnesium (Mg), zinc (Zn), and selenium (Se) in Autism Spectrum Disorder (ASD) using hair, nail and serum samples. A correlation of selected abnormal metal ions with known neurodevelopmental processes using Gene Ontology (GO) term was also conducted. Data included in this review are derived from ASD clinical studies performed globally. Metal ion disparity data is also analyzed and discussed based on gender (Male/Female) to establish any gender dependent correlation. Finally, a rational perspective and possible path to better understand the role of metal micronutrients in ASD is suggested.

Minerals in Pregnancy and Their Impact on Child Growth and Development

During pregnancy, women undergo metabolic and physiological changes, and their needs are higher, to maintain growth and development of the fetus. If the nutritional status of the expectant mother is not satisfactory, some maternal and neonatal complications can occur. In the second and third trimester of pregnancy, there is a reserve of nutrients in the fetus that can be utilized after birth; thereby, children present an accelerated growth in the first years of life, which is a proven response to the available nutrition pattern. However, if such a pattern is insufficient, there will be deficits during development, including brain function. Therefore, despite many recent published works about gestational nutrition, uncertainties still remain on the mechanisms of absorption, distribution, and excretion of micronutrients. Further elucidation is needed to better understand the impacts caused either by deficiency or excess of some micronutrients. Thus, to illustrate the contributions of minerals during prenatal development and in children, iodine, selenium, iron, zinc, calcium, and magnesium were selected. Our study sought to review the consequences related to gestational deficiency of the referred minerals and their impact on growth and development in children born from mothers with such deficiencies

Hair trace element concentrations in autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD)

BACKGROUND

The existing data demonstrate that alteration of trace element and mineral status in children with neurodevelopmental disorders including ASD and ADHD. However, comparative analysis of the specific patterns of trace element and mineral metabolism in children with ASD and ADHD was not performed. Therefore, the primary objective of the present study was to assess hair trace element and mineral levels in boys with ADHD, ASD, as well as ADHD with ASD.

METHODS

Boys with ADHD (n = 52), ASD (n = 53), both ADHD and ASD (n = 52), as well as neurotypical controls (n = 52) were examined. Hair analysis was performed using inductively-coupled plasma mass-spectrometry.

RESULTS

The obtained data demonstrate that hair Co, Mg, Mn, and V levels were significantly reduced in children with ADHD and ASD, and especially in boys with ADHD + ASD. Hair Zn was found to be reduced by 20% (p = 0.009) only in children with ADHD + ASD as compared to healthy controls. Factor analysis demonstrated that ASD was associated with significant alteration of hair Co, Fe, Mg, Mn, and V levels, whereas impaired hair Mg, Mn, and Zn content was also significantly associated with ADHD. In regression models hair Zn and Mg were negatively associated with severity of neurodevelopmental disorders. The revealed similarity of trace element and mineral disturbances in ASD and ADHD may be indicative of certain similar pathogenetic features.

CONCLUSION

The obtained data support the hypothesis that trace elements and minerals, namely Mg, Mn, and Zn, may play a significant role in development of both ADHD and ASD. Improvement of Mg, Mn, and Zn status in children with ASD and ADHD may be considered as a nutritional strategy for improvement of neurodevelopmental disturbances, although clinical trials and experimental studies are highly required to support this hypothesis.

Nutritional status in irritable bowel syndrome: A North American population-based study

Background and Aim

Irritable bowel syndrome (IBS) affects 12% of the population, and the evidence supporting current medical interventions is poor. There is increasing focus on the therapeutic benefit of diet and supplementation. We aim to compare dietary composition and hematologic and biochemical markers in those with and without IBS to determine potential targets for therapeutic supplementation.

Methods

All 17 national surveys between 1959 and 2019 were screened, and only 1, the Second National Health and Nutrition Examination Survey (NHANES II) (1976–1980), provided comprehensive data on IBS. We performed a cross‐sectional analysis of hematologic and biochemical markers and dietary composition of 12 295 individuals, aged 18–74, in NHANES II.

Results

Individuals with IBS had significantly higher copper–zinc ratios (1.70 vs 1.55, P = 0.048) and were more likely to have ratios above 1.8 (odds ratio 1.79, 95% confidence interval 1.02–3.13), indicative of underlying copper–zinc imbalance. While more likely to report dietary avoidances, they had no other evidence of nutritional deficiencies. In addition, dietary recall showed that those with IBS consumed more calories (P = 0.02), were more likely to take vitamin supplements (P = 0.003), and that their macro and micronutrient intake was not significantly different.

Conclusions

The findings suggest that individuals with IBS should be screened for copper–zinc imbalance. Given zinc's role in the immune system, the “brain–gut” axis, and the gastrointestinal barrier, the identified copper–zinc imbalance may play a role in perpetuating the underlying pathophysiology of IBS. Further studies are needed to investigate this hypothesis and the potential role of therapeutic zinc supplementation.

The role of zinc supplementation on the metallothionein system in children with autism spectrum disorder

The present research was carried out to elucidate the role of zinc (Zn) supplementation on the plasma concentration and gene expression, as well as the effects on cognitive-motor performance, in a cohort of children with autism spectrum disorder (ASD). The study was performed on a cohort of 30 pediatric subjects with ASD, encompassing an age range of 3-8 years. The impact of Zn supplementation was investigated in 3 months (or 12 weeks) on the ASD children. Each daily dosage of Zn was calculated as being equal to the body weight in kg plus 15-20 mg. The effect of Zn was also evaluated on the serum level of metallothionein 1 (MT-1A), and the severity of autism via scores on the Childhood Autism Rating Scale. The effect of Zn was investigated on the gene expression of MT1-A before and after Zn supplementation. The data of the present study showed an increase in cognitive-motor performance and an increased serum metallothionein concentration, as well as a significant lowering in the circulating serum levels of copper (Cu) following Zn supplementation. In the cohort of ASD patients, the genetic expression of MT-1 was higher after Zn therapy than before the treatment. In conclusion, Zn supplementation might be an important factor in the treatment of children with ASD.

Zinc Deficiency During Pregnancy Leads to Altered Microbiome and Elevated Inflammatory Markers in Mice

Zinc is an essential trace metal for bacteria of the intestinal flora. Approximately 20% of dietary zinc – intake is used by intestinal bacteria. The microbiome has recently been described as an important factor for healthy brain function via so-called gut-brain interactions. Similarly, zinc deficiency has been associated with neurological problems such as depression, mental lethargy and cognitive impairments in humans and animal models. However, the underlying pathomechanisms are currently not well understood and a link between zinc deficiency and altered microbiota composition has not been studied. Especially during pregnancy, women may be prone to low zinc status. Thus, here, we investigate whether zinc deficiency alters gut-brain interaction in pregnant mice by triggering changes in the microbiome. To that end, pregnant mice were fed different diets being zinc-adequate, deficient in zinc, or adequate in zinc but high in zinc uptake antagonists for 8 weeks. Our results show that acute zinc-deficient pregnant mice and pregnant mice on a diet high in zinc uptake antagonists have an altered composition of gastro-intestinal (GI) microbiota. These changes were accompanied by alterations in markers for GI permeability. Within the brain, we found signs of neuroinflammation. Interestingly, microbiota composition, gut pathology, and inflammatory cytokine levels were partially rescued upon supplementation of mice with zinc amino-acid conjugates (ZnAA). We conclude that zinc deficiency may contribute to abnormal gut-brain signaling by altering gut physiology, microbiota composition and triggering an increase of inflammatory markers.

Zinc and vitamin A deficiency in a cohort of children with autism spectrum disorder

BACKGROUND AND OBJECTIVES

Studies suggest that trace element and vitamin deficiencies are common in children with autism spectrum disorder (ASD). Data describing the rates of vitamin and trace element deficiencies in the ASD population of the northwest of Ireland is lacking. We wished to determine the prevalence of zinc and vitamin A deficiency in the ASD population compared with controls within this geographical area.

METHODS

Parents of children aged 2-18 years with ASD were invited to participate in the study. The control group consisted of well children attending the paediatric department for routine blood sampling. Children on vitamin supplements were excluded from both ASD and control groups. Informed written consent was obtained prior to recruitment. Samples were analysed for zinc and vitamin A levels according to standardized laboratory procedures.

RESULTS

Seventy-four of the 150 children with ASD who were invited and 72 controls underwent blood sampling. Mean zinc and vitamin A levels were normal in both groups. There were significantly more males in the ASD group (88% versus 56%, p value < 0.001). The mean (SD) zinc level was not different between the groups (ASD 11.7 [1.7] versus control 11.6 [2.1] μmol/L, p value = 0.86). The mean (standard deviation) vitamin A level was higher in the ASD group (ASD 350.6 [82.6] versus 319.2 [82.8] μg/L, p value = 0.03), but this was likely confounded by age.

CONCLUSION

Children with ASD in the northwest of Ireland have mean zinc and vitamin A levels within the normal range. It is important that these findings are relayed to health professionals and to parents of children with ASD so that informed decisions on vitamin supplementation can be made.

Altered Intestinal Morphology and Microbiota Composition in the Autism Spectrum Disorders Associated SHANK3 Mouse Model

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by deficits in social interaction and communication, and repetitive behaviors. In addition, co-morbidities such as gastro-intestinal problems have frequently been reported. Mutations and deletion of proteins of the SH3 and multiple ankyrin repeat domains (SHANK) gene-family were identified in patients with ASD, and Shank knock-out mouse models display autism-like phenotypes. SHANK3 proteins are not only expressed in the central nervous system (CNS). Here, we show expression in gastrointestinal (GI) epithelium and report a significantly different GI morphology in Shank3 knock-out (KO) mice. Further, we detected a significantly altered microbiota composition measured in feces of Shank3 KO mice that may contribute to inflammatory responses affecting brain development. In line with this, we found higher E. coli lipopolysaccharide levels in liver samples of Shank3 KO mice, and detected an increase in Interleukin-6 and activated astrocytes in Shank3 KO mice. We conclude that apart from its well-known role in the CNS, SHANK3 plays a specific role in the GI tract that may contribute to the ASD phenotype by extracerebral mechanisms.

Contribution of Zinc and Zinc Transporters in the Pathogenesis of Inflammatory Bowel Diseases

Intestinal epithelial cells cover the surface of the intestinal tract. The cells are important for preserving the integrity of the mucosal barriers to protect the host from luminal antigens and pathogens. The mucosal barriers are maintained by the continuous and rapid self-renewal of intestinal epithelial cells. Defects in the self-renewal of these cells are associated with gastrointestinal diseases, including inflammatory bowel diseases and diarrhea. Zinc is an essential trace element for living organisms, and zinc deficiency is closely linked to the impaired mucosal integrity. Recent evidence has shown that zinc transporters contribute to the barrier function of intestinal epithelial cells. In this review, we describe the recent advances in understanding the role of zinc and zinc transporters in the barrier function and homeostasis of intestinal epithelial cells.

A 16-Year Cohort Analysis of Autism Spectrum Disorder-Associated Morbidity in a Pediatric Population

Introduction: This chapter presents the analysis of physician-diagnosed International Classification of Diseases (ICD version 9) disorders and diseases associated with autism spectrum disorders (ASD) in a 16-year pediatric cohort. Materials and Methods: The sample (n = 47,180; 62% male) consisted of children in the Alberta Health Services Calgary Health Region catchment under the age of 3 years, who received any physician-assigned ICD 9 diagnosis before the age of three between April 1993 and December 31, 1994. There were 111 females and 609 males with ASD diagnosed at any time between 1993 and 2010. The results detail the 16-year odds ratio (OR) associations of ASD diagnosis within the major classes of international classification of diseases (ICD 9) stratified by age and sex in the cohort. Further, for those suffering from ASD and any other disorder or disease, the analysis presents by sex, age, and duration, the proportions of all index physician-assigned ICD diagnoses, arising significantly before and after the index ASD diagnosis. Results: The rate of treated ASD in the cohort was 1 in 65 and the 16-year population rate of ASD was 62 per 10,000. For males with an ASD over the 16 year period, the ORs were significantly greater than the value one for 15 of the 17 main ICD classes and for 10 of the main ICD classes for females. Different age strata presented a more specific account of the main ICD class OR profiles. More specifically, 28 ICD disorders significantly preceded and 95 ICD disorders significantly followed ASD for females. Thirty-eight ICD disorders significantly preceded and 234 ICD disorders significantly followed ASD for males. Conclusions: The results largely confirm past studies focusing on more constrained sets of ASD morbidity. The age-stratified ORs gauge the order of risk in time for the cohort. The proportions of specific ICD disorders arising before and after ASD may be useful in respect to informing basic ASD research and ASD clinical management. Limitations are discussed.

Zinc signaling and epilepsy

Evidence from both preclinical and clinical studies suggest the importance of zinc homeostasis in seizures/epilepsy. Undoubtedly, zinc, via modulation of a variety of targets, is necessary for maintaining the balance between neuronal excitation and inhibition, while an imbalance between excitation and inhibition underlies seizures. However, the relationship between zinc signaling and seizures/epilepsy is complex as both extracellular and intracellular zinc may produce either protective or detrimental effects. This review provides an overview of preclinical/behavioral, functional and molecular studies, as well as clinical data on the involvement of zinc in the pathophysiology and treatment of seizures/epilepsy. Furthermore, the potential of targeting elements associated with zinc signaling or homeostasis and zinc levels as a therapeutic strategy for epilepsy is discussed.

Plasma concentrations of the trace elements copper, zinc and selenium in Brazilian children with autism spectrum disorder

The association between the plasma levels of trace elements, such as copper (Cu), zinc (Zn) and selenium (Se), in people with autism spectrum disorder (ASD), has attracted the interest of many physicians in the very recent years, because the impaired homeostatic regulation of trace elements, including their levels in the bloodstream and their potential neurotoxicity, contribute to the onset and exacerbation of ASD. In this study, we investigated 23 pediatric subjects (≤ 18 yrs old, both sexes) with ASD, all residents in the city of Campo Grande in Brazil, by searching for their micronutrient levels in plasma in relation with metabolic and nutrition biomarkers. Aside for the few evidence reported, generally, the Brazilian cohort of ASD children here examined did not show a marked difference in micro-nutrient intake in relation with their resident geographical area and their dietary habit or metabolic state, although a slight difference in the levels of magnesium and phosphorus was retrieved due to sex difference.

Prospects of Zinc Supplementation in Autism Spectrum Disorders and Shankopathies Such as Phelan McDermid Syndrome

The loss of one copy of SHANK3 (SH3 and multiple ankyrin repeat domains 3) in humans highly contributes to Phelan McDermid syndrome (PMDS). In addition, SHANK3 was identified as a major autism candidate gene. Interestingly, the protein encoded by the SHANK3 gene is regulated by zinc. While zinc deficiency depletes synaptic pools of Shank3, increased zinc levels were shown to promote synaptic scaffold formation. Therefore, the hypothesis arises that patients with PMDS and Autism caused by Shankopathies, having one intact copy of SHANK3 left, may benefit from zinc supplementation, as elevated zinc may drive remaining Shank3 into the post-synaptic density (PSD) and may additional recruit Shank2, a second zinc-dependent member of the SHANK gene family. Further, elevated synaptic zinc levels may modulate E/I ratios affecting other synaptic components such as NMDARs. However, several factors need to be considered in relation to zinc supplementation such as the role of Shank3 in the gastrointestinal (GI) system-the location of zinc absorption in humans. Therefore, here, we briefly discuss the prospect and impediments of zinc supplementation in disorders affecting Shank3 such as PMDS and propose a model for most efficacious supplementation.