Functional contribution of the intestinal microbiome in autism spectrum disorder, attention deficit hyperactivity disorder, and Rett syndrome: a systematic review of pediatric and adult studies.

Introduction: Critical phases of neurodevelopment and gut microbiota diversification occur in early life and both processes are impacted by genetic and environmental factors. Recent studies have shown the presence of gut microbiota alterations in neurodevelopmental disorders. Here we performed a systematic review of alterations of the intestinal microbiota composition and function in pediatric and adult patients affected by autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Rett syndrome (RETT). Methods: We searched selected keywords in the online databases of PubMed, Cochrane, and OVID (January 1980 to December 2021) with secondary review of references of eligible articles. Two reviewers independently performed critical appraisals on the included articles using the Critical Appraisal Skills Program for each study design. Results: Our systematic review identified 18, 7, and 3 original articles describing intestinal microbiota profiles in ASD, ADHD, and RETT, respectively. Decreased Firmicutes and increased Bacteroidetes were observed in the gut microbiota of individuals affected by ASD and ADHD. Proinflammatory cytokines, short-chain fatty acids and neurotransmitter levels were altered in ASD and RETT. Constipation and visceral pain were related to changes in the gut microbiota in patients affected by ASD and RETT. Hyperactivity and impulsivity were negatively correlated with Faecalibacterium (phylum Firmicutes) and positively correlated with Bacteroides sp. (phylum Bacteroidetes) in ADHD subjects. Five studies explored microbiota-or diet-targeted interventions in ASD and ADHD. Probiotic treatments with Lactobacillus sp. and fecal microbiota transplantation from healthy donors reduced constipation and ameliorated ASD symptoms in affected children. Perinatal administration of Lactobacillus sp. prevented the onset of Asperger and ADHD symptoms in adolescence. Micronutrient supplementation improved disease symptomatology in ADHD without causing significant changes in microbiota communities' composition. Discussion: Several discrepancies were found among the included studies, primarily due to sample size, variations in dietary practices, and a high prevalence of functional gastrointestinal symptoms. Further studies employing longitudinal study designs, larger sample sizes and multi-omics technologies are warranted to identify the functional contribution of the intestinal microbiota in developmental trajectories of the human brain and neurobehavior. Systematic review registration: https://clinicaltrials.gov/, CRD42020158734.

Nutritional Therapies and Their Influence on the Intestinal Microbiome in Pediatric Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic, autoimmune disorder of the gastrointestinal tract with numerous genetic and environmental risk factors. Patients with Crohn's disease (CD) or ulcerative colitis (UC) often demonstrate marked disruptions of their gut microbiome. The intestinal microbiota is strongly influenced by diet. The association between the increasing incidence of IBD worldwide and increased consumption of a westernized diet suggests host nutrition may influence the progression or treatment of IBD via the microbiome. Several nutritional therapies have been studied for the treatment of CD and UC. While their mechanisms of action are only partially understood, existing studies do suggest that diet-driven changes in microbial composition and function underlie the diverse mechanisms of nutritional therapy. Despite existing therapies for IBD focusing heavily on immune suppression, nutrition is an important treatment option due to its superior safety profile, potentially low cost, and benefits for growth and development. These benefits are increasingly important to patients. In this review, we will describe the clinical efficacy of the different nutritional therapies that have been described for the treatment of CD and UC. We will also describe the effects of each nutritional therapy on the gut microbiome and summarize the strength of the literature with recommendations for the practicing clinician.

Reduction of Central Line-Associated Bloodstream Infections and Line Occlusions in Pediatric Intestinal Failure Patients Receiving Long-Term Parenteral Nutrition Using an Alternative Locking Solution, 4% Tetrasodium Ethylenediaminetetraacetic Acid.

BACKGROUND: Patients with intestinal failure (IF) are dependent on parenteral nutrition (PN), however, they are at risk of central line-associated bloodstream infections (CLABSIs) and line complications. Four-percent tetrasodium ethylenediaminetetraacetic acid (EDTA) solution is an effective nonantibiotic, antimicrobial, antibiofilm, and anticoagulant agent. Our objective was to determine 4% tetrasodium EDTA efficacy in preventing CLABSIs and reducing line occlusions in pediatric IF patients. METHODS: We conducted a retrospective cohort study of patients managed at 2 tertiary Canadian pediatric centers between April 2016 and December 2018 who received 4% tetrasodium EDTA solution under the brand name Kitelock. Data were collected for 12 months pre and post-Kitelock. CLABSIs and alteplase administration were compared using a Wilcoxon matched-pairs signed-rank test. Data were reported as medians and frequencies. RESULTS: Twenty patients were included (10 boys; median age, 83 months [range, 8-232 months]). The rate of CLABSIs before 4% tetrasodium EDTA was 2.7+4 per 1000 catheter days. Patients received 4% tetrasodium EDTA for a median of 365 (278-365) days, with no infections in the 12 months post-therapy (P = .002). Median rates of occlusive episodes for the entire cohort before 4% tetrasodium EDTA were 0 (0-5.0) and 0 (0-2.0) after starting therapy (P = .018). In patients with previous occlusions (n = 9), the median episodes of alteplase use previously was 5.5 (2.7-19.2) compared with 2.7 (0-2.7) (P = .018). CONCLUSIONS: Our preliminary findings suggest 4% tetrasodium EDTA solution is effective in reducing CLABSIs and catheter occlusions in pediatric patients with long-term central-access.

Effect of Exclusive Enteral Nutrition and Corticosteroid Induction Therapy on the Gut Microbiota of Pediatric Patients with Inflammatory Bowel Disease.

INTRODUCTION: Exclusive enteral nutrition (EEN) and corticosteroids (CS) are effective induction therapies for pediatric Crohn's Disease (CD). CS are also therapy for ulcerative colitis (UC). Host-microbe interactions may be able to explain the effectiveness of these treatments. This is the first prospective study to longitudinally characterize compositional changes in the bacterial community structure of pediatric UC and CD patients receiving EEN or CS induction therapy. METHODS: Patients with diagnoses of CD or UC were recruited from McMaster Children's Hospital (Hamilton, Canada). Fecal samples were collected from participants aged 5-18 years old undergoing 8 weeks of induction therapy with EEN or CS. Fecal samples were submitted for 16S rRNA sequencing. The Shannon diversity index and the relative abundance of specific bacterial taxa were compared using a linear mixed model. RESULTS: The clustering of microbiota was the highest between patients who achieved remission compared to patients still showing active disease (p = 0.029); this effect was independent of the diagnosis or treatment type. All patients showed a significant increase in Shannon diversity over the 8 weeks of treatment. By week 2, a significant difference was seen in Shannon diversity between patients who would go on to achieve remission and those who would not. CONCLUSION: The gut microbiota of pediatric UC and CD patients was most influenced by patients' success or failure to achieve remission and was largely independent of the choice of treatment or disease type. Significant differences in Shannon diversity indices occurred as early as week 2 between patients who went on to achieve remission and those who continued to have active disease.

Protocol for a randomised, placebo-controlled pilot study for assessing feasibility and efficacy of faecal microbiota transplantation in a paediatric ulcerative colitis population: PediFETCh trial.

INTRODUCTION: Ulcerative colitis (UC) is a chronic, relapsing condition characterised by colonic inflammation. Increasing prevalence in early-age diagnosis provides opportunities for additional complications in later life as a result of prolonged exposure to inflammatory and therapeutic insults, necessitating novel avenues for therapeutics which may result in fewer side effects. Faecal microbiota transplantation (FMT) has previously demonstrated potential therapeutic benefit in an adult randomised-controlled trial and several recurrent Clostridium difficile infection studies. This phase Ib pilot will be the first randomised, single-blinded, placebo-controlled trial to assess feasibility and patient outcomes in a paediatric inflammatory bowel disease (IBD) population. METHODS AND ANALYSIS: Fifty patients will be randomised 1:1 to receive normal saline control or active sample. Enema administrations will be performed two times per week for 6 weeks, followed at a 6-month follow-up period. Feasibility outcomes will include measures of patient eligibility, recruitment, willingness to participate, samples collections, hospitalizations and drop-out rate. Improvements in disease symptoms will determine the efficacy of treatment. Clinical disease scores will be taken throughout the study period using the Paediatric Ulcerative Colitis Activity Index (PUCAI). Monitoring of inflammatory markers in blood and stool will be performed at regular intervals. Microbiome analysis will be conducted on stool samples collected throughout the trials period. Imaging and endoscopic surveillance will be conducted if clinically necessary. ETHICS AND DISSEMINATION: Ethics was obtained from local hospital research ethics boards across all three sites. Health Canada and FDA approval was obtained for the use of an Investigatory New Drug product. Results from this trial will be presented in international conferences and published in peer-review journals. TRIAL REGISTRATION NUMBER: Trial registration number: NCT02487238; preresults.