Use this URL to cite or link to this record in EThOS:
Title: Investigation of the gut microbiota of children with austistic spectrum disorders and the therapeutical potential of probiotics
Author: Parracho, Helena Maria Ramalho Tomé
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2007
Availability of Full Text:
Access from EThOS:
Autism is a spectrum of developmental disorders, with onset in early childhood affecting social, communicative and imaginative development. Numerous theories have been proposed regarding the aetiology of autistic spectrum disorders (ASD), yet the condition remains poorly understood. Children with ASD tend to suffer from severe dietary and/or gastrointestinal (GI) problems (including abdominal pain, constipation, diarrhoea and bloating). These symptoms may be associated with disruption of the indigenous gut flora promoting overgrowth of potentially pathogenic (toxin producing) microorganisms. The primary aim of this research was to provide a detail overview of the gut microbiota of ASD children and study the effect of selected probiotics on the gut microbiota, gut function and associated symptoms (i. e. behaviour) of ASD children. The gut microbiota of ASD children was compared to that of non-ASD control groups (siblings and unrelated children). Changes in bacterial gut populations were assessed using fluorescence in situ hybridisation (FISH) targeting relevant gut bacterial groups in a culture independent manner. The gut microbiota of ASD children contained higher levels of Clostridium histolyticum subgroup (Clostridium clusters I and II) bacteria than that of non-ASD children. Screening probiotic bacteria for their ability to inhibit the growth of Clostridium perfringens was assessed in vitro. Six probiotics (namely, L. plantarum NCIMB 41114, L. acidophilus JVT5, L. pentosus JCM 1558, L. rhamnosus GG 1003, L. plantarum 903 and L. plantarum WCFS1) showed statistically significant inhibition of C. perfringens (although many others were also tested). These probiotics were further tested in batch culture fermentation systems to investigate whether they could beneficially modulate the faecal bacterial populations of children with ASD. Probiotic supplementations increased the levels of lactobacilli/enterococci populations and demonstrated a degree of anti-microbial action against C. histolyticum subgroup. L. plantarum WCFS 1 was then used in a double-blind, placebo-controlled, randomized cross-over feeding study in ASD. Administration of L. plantarum WCFSI significantly increased numbers of lactobacilli/enterococci in the faecal flora of ASD children compared to a placebo. No modulation of the C. histolyticum subgroup was seen during the study. A significant improvement in bowel function was observed with probiotic administration. Moreover, the total behaviour problem score was significantly lower after L. plantarum WCFS 1 administration compared to the placebo. This study supports the hypothesis that probiotic therapy may modulate the, GI microbiota composition in ASD individuals and alleviate GI symptoms of ASD individuals.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available