The intestinal lesion of autistic spectrum disorder

Eating behaviors, diet quality, and gastrointestinal symptoms in children with autism spectrum disorders: a brief review

Children with autism spectrum disorders (ASD) and their caregivers face unique challenges in the children's daily eating routines and food intake patterns. The aim of this brief review is to describe eating behaviors of children with ASD, including increased food neophobia and food selectivity, and review findings on children's diet quality, and gastrointestinal (GI) symptoms. Advancing knowledge about the interrelationships between these nutrition-related domains in children with ASD is expected to have important implications for clinical nursing practice and caregiver care.

Review article: intestinal lymphoid nodular hyperplasia in children--the relationship to food hypersensitivity

BACKGROUND

Lymphoid aggregates are normally found throughout the small and large intestine. Known as lymphoid nodular hyperplasia (LNH), these aggregates are observed especially in young children and are not associated with clinical symptoms being considered 'physiological'. In children presenting with gastrointestinal symptoms the number and size of the lymphoid follicles are increased. Patients suffering from gastrointestinal symptoms (i.e. recurrent abdominal pain) should systematically undergo gastroduodenoscopy and colonoscopy. With these indications LNH, especially of the upper but also of the lower gastrointestinal tract has been diagnosed, and in some children it may reflect a food hypersensitivity (FH) condition.

AIM

To review the literature about the relationship between LNH and FH, particularly focusing on the diagnostic work-up for LNH related to FH.

METHODS

We reviewed literature using Pubmed and Medline, with the search terms 'lymphoid nodular hyperplasia', 'food hypersensitivity', 'food allergy' and 'food intolerance'. We overall examined 10 studies in detail, selecting articles about the prevalence of LNH in FH patients and of FH in LNH patients.

RESULTS

Collected data showed a median of 49% (range 32-67%) LNH in FH patients and a median of 66% (range 42-90%) FH in LNH patients. Literature review pointed out that the most important symptom connected with LNH and/or FH was recurrent abdominal pain, followed by diarrhoea and growth retardation. Both LNH and FH are associated with an increase in lamina propria γ/δ+ T cells, but the mechanisms by which enhanced local immune responses causing gastrointestinal symptoms still remain obscure.

CONCLUSIONS

When assessing FH, we rely on clinical evaluation, including elimination diet and challenge tests, and endoscopic and immunohistochemical findings. Considering the possible co-existence of duodenal and ileo-colonic LNH, upper endoscopy can be recommended in children with suspected FH, especially in those presenting with additional upper abdominal symptoms (i.e. vomiting). Likewise, lower endoscopy might be additionally performed in patients with suspected FH and LNH of the duodenal bulb, also presenting with lower abdominal symptoms (i.e. recurrent abdominal pain).

Alterations of the intestinal barrier in patients with autism spectrum disorders and in their first-degree relatives

OBJECTIVES

Intestinal permeability (IPT) was investigated in patients with autism as well as in their first-degree relatives to investigate leaky gut hypothesis. Faecal calprotectin (FC) was also measured in patients with autism, either with or without gastrointestinal symptoms, and in their first-degree relatives.

PATIENTS AND METHODS

IPT results, assessed by means of the lactulose/mannitol test, were compared with adult and child controls and with FC values.

RESULTS

A high percentage of abnormal IPT values were found among patients with autism (36.7%) and their relatives (21.2%) compared with normal subjects (4.8%). Patients with autism on a reported gluten-casein-free diet had significantly lower IPT values compared with those who were on an unrestricted diet and controls. Gastrointestinal symptoms were present in 46.7% of children with autism: constipation (45.5%), diarrhoea (34.1%), and others (alternating diarrhoea/constipation, abdominal pain, etc: 15.9%). FC was elevated in 24.4% of patients with autism and in 11.6% of their relatives; it was not, however, correlated with abnormal IPT values.

CONCLUSIONS

The results obtained support the leaky gut hypothesis and indicate that measuring IPT could help to identify a subgroup of patients with autism who could benefit from a gluten-free diet. The IPT alterations found in first-degree relatives suggest the presence of an intestinal (tight-junction linked) hereditary factor in the families of subjects with autism.

Autistic spectrum disorders as functional disconnection syndrome

We outline the basis of how functional disconnection with reduced activity and coherence in the right hemisphere would explain all of the symptoms of autistic spectrum disorder as well as the observed increases in sympathetic activation. If the problem of autistic spectrum disorder is primarily one of desynchronization and ineffective interhemispheric communication, then the best way to address the symptoms is to improve coordination between areas of the brain. To do that the best approach would include multimodal therapeusis that would include a combination of somatosensory, cognitive, behavioral, and biochemical interventions all directed at improving overall health, reducing inflammation and increasing right hemisphere activity to the level that it becomes temporally coherent with the left hemisphere. We hypothesize that the unilateral increased hemispheric stimulation has the effect of increasing the temporal oscillations within the thalamocortical pathways bringing it closer to the oscillation rate of the adequately functioning hemisphere. We propose that increasing the baseline oscillation speed of one entire hemisphere will enhance the coordination and coherence between the two hemispheres allowing for enhanced motor and cognitive binding.

Intersubjectivity, affective neuroscience, and the neurobiology of autistic spectrum disorders: a systematic review

Intersubjectivity is an approach to the study of social interaction viewed from a perspective which rejects the view that reducing any such analysis to study at the level of the individual is adequate to address the issues of social functioning. It also stresses the view that social processes cannot be reduced to cognitive ones - most of the important questions in the study of developmental psychopathology deal with issues which have commonality with many other species and are patent well before the ontological emergence of 'cognitive' abilities. In this paper we review the evidence in this area, and discuss a range of issues relevant to autistic spectrum disorders. We focus in particular on social interaction; the role of the Intrinsic Motive Formation and recent work on mirror neurons in autism; genetic and teratogenic factors in the genesis of autism; and the role of a number of biological factors in pathogenesis - tryptophan; vitamin B12; sterol metabolism; glutamate and GABA; and the Fragile-X expansion.

Colonic lymphoid nodular hyperplasia in children: relationship to food hypersensitivity

BACKGROUND & AIMS

The clinical significance of lymphoid nodular hyperplasia (LNH) of the lower gastrointestinal tract is unclear. The aim of this study was to define the frequency and clinical significance of LNH in pediatric patients undergoing colonoscopy.

METHODS

Two hundred forty-five children (101 male, 144 female; median age, 8.5 years) for whom colonoscopy had been indicated were evaluated during a 3-year period. Apart from ileocolonoscopy with biopsy, all patients underwent routine biochemistry, serum total and specific IgE, and/or skin prick tests for food allergens. Patients with LNH underwent elimination diet and subsequent food challenges.

RESULTS

LNH was observed in 73 of 245 (30%) consecutive colonoscopies. LNH was the only abnormal finding in 52 of the 73 cases (71%). In 43 of these 52 patients a diagnosis of cow's milk or multiple food hypersensitivity was made. Food allergy was significantly more common than in patients without LNH (83% vs 31%; P < .0001). The patients with LNH and food hypersensitivity presented hematochezia (P < .0001), elevated serum anti-beta-lactoglobulin IgG (P < .0001), anemia (P < .005), and failure to thrive (P < .03) more frequently than those without LNH. In the LNH patients histologic examination showed a higher number of lymphoid follicles throughout the colon and the terminal ileum and an increased number of lamina propria and intraepithelial eosinophils.

CONCLUSIONS

The presence of LNH in the colon and/or terminal ileum is a frequent finding in symptomatic children undergoing colonoscopy. Unless associated with other specific endoscopic or histologic lesions, LNH is related to a condition of delayed-type food hypersensitivity.

Autism and environmental genomics

Autism spectrum disorders (ASD) are defined by behavior and diagnosed by clinical history and observation but have no biomarkers and are presumably, etiologically and biologically heterogeneous. Given brain abnormalities and high monozygotic concordance, ASDs have been framed as neurobiologically based and highly genetic, which has shaped the research agenda and in particular criteria for choosing candidate ASD genes. Genetic studies to date have not uncovered genes of strong effect, but a move toward "genetic complexity" at the neurobiological level may not suffice, as evidence of systemic abnormalities (e.g. gastrointestinal and immune), increasing rates and less than 100% monozygotic concordance support a more inclusive reframing of autism as a multisystem disorder with genetic influence and environmental contributors. We review this evidence and also use a bioinformatic approach to explore the possibility that "environmentally responsive genes" not specifically associated with the nervous system, but potentially associated with systemic changes in autism, have not hitherto received sufficient attention in autism genetics investigations. We overlapped genes from NIEHS Environmental Genome Project, the Comparative Toxicogenomics Database, and the SeattleSNPs database of genes relevant to the human immune and inflammatory response with linkage regions identified in published autism genome scans. We identified 135 genes in overlap regions, of which 56 had never previously been studied in relation to autism and 47 had functional SNPs (in coding regions). Both our review and the bioinformatics exercise support the expansion of criteria for evaluating the relevance of genes to autism risk to include genes related to systemic impact and environmental responsiveness. This review also suggests the utility of environmental genomic resources in highlighting the potential relevance of particular genes within linkage regions. Environmental responsiveness and systems impacts consistent with system-wide findings in autism are thus supported as important considerations in identifying the numerous and complex modes of gene-environment interaction in autism.