Alpha-1-antitrypsin, autism, and coeliac disease

Gluten and Autism Spectrum Disorder

An expanding body of literature is examining connections between Autism Spectrum Disorder (ASD) and dietary interventions. While a number of specialist diets have been suggested as beneficial in ASD, gluten has received particularly close attention as a potentially exacerbating factor. Reports exist suggesting a beneficial effect of the gluten-free diet (GFD) in ameliorating behavioural and intellectual problems associated with ASD, while epidemiological research has also shown a comorbidity between ASD and coeliac disease. However, both caregivers and clinicians have expressed an uncertainty of the value of people with ASD going gluten-free, and as the GFD otherwise receives considerable public attention a discussion which focuses specifically on the interaction between ASD and gluten is warranted. In this review we discuss the historical context of ASD and gluten-related studies, and expand this to include an overview of epidemiological links, hypotheses of shared pathological mechanisms, and ultimately the evidence around the use and adoption of the GFD in people with ASD.

Infant colic or early symptom of autism spectrum disorder?

BACKGROUND

Gastrointestinal (GI) disorders are common in autism spectrum disorder (ASD). Infant colic (IC), the functional GI disorder of infancy, has not been evaluated in this patient group. The aim of this study was therefore to determine the rate of IC in ASD and investigate a possible association between ASD and IC.

METHODS

The subjects consisted of 100 ASD patients (mean age, 6.6 ± 3.5 years) and 100 healthy controls (mean age, 5.3 ± 2.8 years). The parents were questioned using the diagnostic criteria for infant colic for clinical research purposes defined in Rome IV to diagnose IC, retrospectively. The sample size was estimated using a maximum type I error probability of 5% (alpha) and a type II error of 20%.

RESULTS

The rate of IC was 16% and 17% in the ASD group and control group, respectively (P ˃ 0.05). Excessive crying with late onset and long duration in infants was defined as persistent crying. The rate of persistent crying was significantly higher in the ASD group than in the control group (32% vs 9%, P < 0.001). The relative risk of persistent crying was 4.40 in ASD. The likelihood of being misdiagnosed with IC in this group was 78%.

CONCLUSION

The rate of IC is not increased in patients with ASD, but infants with excessive crying should be very thoroughly evaluated before being diagnosed with IC. In particular, persistent crying in infants (i.e. excessive crying with late onset and long duration) may be an early symptom of ASD.

Differential immune responses and microbiota profiles in children with autism spectrum disorders and co-morbid gastrointestinal symptoms

OBJECTIVES

Many studies have reported the increased presence of gastrointestinal (GI) symptoms in children with autism spectrum disorders (ASD). Altered microbiome profiles, pro-inflammatory responses and impaired intestinal permeability have been observed in children with ASD and co-morbid GI symptoms, yet few studies have compared these findings to ASD children without GI issues or similarly aged typical developing children. The aim of this study was to determine whether there are biological signatures in terms of immune dysfunction and microbiota composition in children with ASD with GI symptoms.

METHODS

Children were enrolled in one of four groups: ASD and GI symptoms of irregular bowel habits (ASDGI), children with ASD but without current or previous GI symptoms (ASDNoGI), typically developing children with GI symptoms (TDGI) and typically developing children without current or previous GI symptoms (TDNoGI). Peripheral blood mononuclear cells (PBMC) were isolated from the blood, stimulated and assessed for cytokine production, while stool samples were analyzed for microbial composition.

RESULTS

Following Toll-Like receptor (TLR)-4 stimulation, the ASDGI group produced increased levels of mucosa-relevant cytokines including IL-5, IL-15 and IL-17 compared to ASDNoGI. The production of the regulatory cytokine TGFβ1 was decreased in the ASDGI group compared with both the ASDNoGI and TDNoGI groups. Analysis of the microbiome at the family level revealed differences in microbiome composition between ASD and TD children with GI symptoms; furthermore, a predictive metagenome functional content analysis revealed that pathways were differentially represented between ASD and TD subjects, independently of the presence of GI symptoms. The ASDGI also showed an over-representation of the gene encoding zonulin, a molecule regulating gut permeability, compared to the other groups.

CONCLUSIONS

Overall our findings suggest that children with ASD who experience GI symptoms have an imbalance in their immune response, possibly influenced by or influencing metagenomic changes, and may have a propensity to impaired gut barrier function which may contribute to their symptoms and clinical outcome.

Is urinary indolyl-3-acryloylglycine a biomarker for autism with gastrointestinal symptoms?

An autism spectrum disorder (ASD) diagnosis is based on clinical behaviours as there are no validated biological diagnostic tools. Indolyl-3-acryloylglycine (IAG) is a chemical produced by gut microflora and there are conflicting reports as to whether urinary levels are elevated in children with ASD compared with controls. Urinary IAG levels in morning urine samples were statistically significantly higher in children with ASD whose caregivers reported the presence of chronic gastrointestinal (GI) disturbance than children with ASD without chronic GI disturbance. Urinary IAG, however, was not statistically significantly higher in children with ASD, compared with siblings or unrelated controls without ASD.

Low Serum Alpha-1 Antitrypsin (AAT) in Family Members of Individuals with Autism Correlates with PiMZ Genotype

AIM

Deficiency of Alpha-1-antitrypsin (AAT) can be a genetic condition that increases the risk of developing liver, lung and possibly gastrointestinal disease. Since many autistic children also have gastrointestinal disorders, this study was designed to measure serum concentration of AAT and establish AAT genotypes in autistic children, age and gender matched non-autistic siblings, parents and controls.

SUBJECTS AND METHODS

We used an indirect ELISA with monoclonal IgG to AAT to measure AAT serum concentrations in 71 members from 16 families of individuals with autism and 18 controls (no family history of autism). We used a duplex polymerase chain reaction to detect M, S and Z alleles for alpha-1 antitrypsin expression in 52 members of 12 of the above families.

RESULTS

A significantly high number of autistic family members had lower than normal serum levels of AAT when compared to controls. Autistic children with regressive onset had significantly lower levels of AAT compared to controls, and a significant number of autistic children with low serum AAT also had hyperbilirubinemia, gastrointestinal disease and respiratory problems. We also found that a significantly high number of these individuals had the PiMZ genotype and correspondingly low levels of serum alpha-1 antitrypsin.

DISCUSSION

Knowing that low levels of alpha-1 antitrypsin may be inherited, and that low levels of AAT may be associated with GI disease in autistic children, genotyping autistic children may help identify individuals susceptible to developing digestive problems.

Teratoma of the umbilical cord in a giraffe (Giraffa camelopardalis reticulata)

A 12-year-old pregnant female giraffe (Giraffa camelopardalis reticulata) died approximately 2 months prior to her anticipated parturition date. At necropsy, a mass measuring approximately 20 x 36 x 20 cm was observed, attached to the umbilical cord, the latter being otherwise normal in appearance. Histologically, the mass contained 3 germinal tissue components with areas of squamous epithelium, respiratory epithelium, primitive neural tissues, glial tissue, peripheral nerve, adipose tissue, cartilage, and smooth muscle. Based on these findings, the tumor was diagnosed as a teratoma originating from the umbilical cord. This is possibly the second reported case of umbilical cord teratoma in animals.

Gastrointestinal factors in autistic disorder: a critical review

Interest in the gastrointestinal (GI) factors of autistic disorder (autism) has developed from descriptions of symptoms such as constipation and diarrhea in autistic children and advanced towards more detailed studies of GI histopathology and treatment modalities. This review attempts to critically and comprehensively analyze the literature as it applies to all aspects of GI factors in autism, including discussion of symptoms, pathology, nutrition, and treatment. While much literature is available on this topic, a dearth of rigorous study was found to validate GI factors specific to children with autism.

Frequency of gastrointestinal symptoms in children with autistic spectrum disorders and association with family history of autoimmune disease

This is a cross-sectional study that compares lifetime prevalence of gastrointestinal (GI) symptoms in children with autistic spectrum disorders (ASDs) and children with typical development and with other developmental disabilities (DDs) and examines the association of GI symptoms with a family history of autoimmune disease. A structured interview was performed in 50 children with ASD and 2 control groups matched for age, sex, and ethnicity-50 with typical development and 50 with other DDs. Seventy-four percent were boys with a mean age of 7.6 years (SD, +/-3.6). A history of GI symptoms was elicited in 70% of children with ASD compared with 28% of children with typical development (p <.001) and 42% of children with DD (p =.03). Abnormal stool pattern was more common in children with ASD (18%) than controls (typical development: 4%, p =.039; DD: 2%, p =.021). Food selectivity was also higher in children with ASD (60%) compared with those with typical development (22%, p =.001) and DD (36%, p =.023). Family history of autoimmune disease was reported in 38% of the ASD group and 34% of controls and was not associated with a differential rate of GI symptoms. In the multivariate analysis, autism (adjusted odds ratio (OR), 3.8; 95% confidence interval (CI), 1.7-11.2) and food selectivity (adjusted OR, 4.1; 95% CI, 1.8-9.1) were associated with GI symptoms. Children with ASD have a higher rate of GI symptoms than children with either typical development or other DDs. In this study, there was no association between a family history of autoimmune disease and GI symptoms in children with ASD.

Autistic disorder and gastrointestinal disease

Autistic disorder is a pervasive developmental disorder manifested in the first 3 years of life by dysfunction in social interaction and communication. Many efforts have been made to explore the biologic basis of this disorder, but the etiology remains unknown. Recent publications describing upper gastrointestinal abnormalities and ileocolitis have focused attention on gastrointestinal function and morphology in these children. High prevalence of histologic abnormalities in the esophagus, stomach, small intestine and colon, and dysfunction of liver conjugation capacity and intestinal permeability were reported. Three surveys conducted in the United States described high prevalence of gastrointestinal symptoms in children with autistic disorder. Treatment of the digestive problems may have positive effects on their behavior.

Autism and gastrointestinal symptoms

Autism is a collection of behavioral symptoms characterized by dysfunction in social interaction and communication in affected children. It is typically associated with restrictive, repetitive, and stereotypic behavior and manifests within the first 3 years of life. The cause of this disorder is not known. Over the past decade, a significant upswing in research has occurred to examine the biologic basis of autism. Recent clinical studies have revealed a high prevalence of gastrointestinal symptoms, inflammation, and dysfunction in children with autism. Mild to moderate degrees of inflammation were found in both the upper and lower intestinal tract. In addition, decreased sulfation capacity of the liver, pathologic intestinal permeability, increased secretory response to intravenous secretin injection, and decreased digestive enzyme activities were reported in many children with autism. Treatment of digestive problems appears to have positive effects on autistic behavior. These new observations represent only a piece of the unsolved autism "puzzle" and should stimulate more research into the brain-gut connection.

Colonic CD8 and gamma delta T-cell infiltration with epithelial damage in children with autism

OBJECTIVES

We have reported colitis with ileal lymphoid nodular hyperplasia (LNH) in children with regressive autism. The aims of this study were to characterize this lesion and determine whether LNH is specific for autism.

METHODS

Ileo-colonoscopy was performed in 21 consecutively evaluated children with autistic spectrum disorders and bowel symptoms. Blinded comparison was made with 8 children with histologically normal ileum and colon, 10 developmentally normal children with ileal LNH, 15 with Crohn's disease, and 14 with ulcerative colitis. Immunohistochemistry was performed for cell lineage and functional markers, and histochemistry was performed for glycosaminoglycans and basement membrane thickness.

RESULTS

Histology demonstrated lymphocytic colitis in the autistic children, less severe than classical inflammatory bowel disease. However, basement membrane thickness and mucosal gamma delta cell density were significantly increased above those of all other groups including patients with inflammatory bowel disease. CD8(+) density and intraepithelial lymphocyte numbers were higher than those in the Crohn's disease, LNH, and normal control groups; and CD3 and plasma cell density and crypt proliferation were higher than those in normal and LNH control groups. Epithelial, but not lamina propria, glycosaminoglycans were disrupted. However, the epithelium was HLA-DR(-), suggesting a predominantly T(H)2 response.

INTERPRETATION

Immunohistochemistry confirms a distinct lymphocytic colitis in autistic spectrum disorders in which the epithelium appears particularly affected. This is consistent with increasing evidence for gut epithelial dysfunction in autism.

Gastrointestinal abnormalities in children with autistic disorder

OBJECTIVES

Our aim was to evaluate the structure and function of the upper gastrointestinal tract in a group of patients with autism who had gastrointestinal symptoms.

STUDY DESIGN

Thirty-six children (age: 5.7 +/- 2 years, mean +/- SD) with autistic disorder underwent upper gastrointestinal endoscopy with biopsies, intestinal and pancreatic enzyme analyses, and bacterial and fungal cultures. The most frequent gastrointestinal complaints were chronic diarrhea, gaseousness, and abdominal discomfort and distension.

RESULTS

Histologic examination in these 36 children revealed grade I or II reflux esophagitis in 25 (69.4%), chronic gastritis in 15, and chronic duodenitis in 24. The number of Paneth's cells in the duodenal crypts was significantly elevated in autistic children compared with non-autistic control subjects. Low intestinal carbohydrate digestive enzyme activity was reported in 21 children (58.3%), although there was no abnormality found in pancreatic function. Seventy-five percent of the autistic children (27/36) had an increased pancreatico-biliary fluid output after intravenous secretin administration. Nineteen of the 21 patients with diarrhea had significantly higher fluid output than those without diarrhea.

CONCLUSIONS

Unrecognized gastrointestinal disorders, especially reflux esophagitis and disaccharide malabsorption, may contribute to the behavioral problems of the non-verbal autistic patients. The observed increase in pancreatico-biliary secretion after secretin infusion suggests an upregulation of secretin receptors in the pancreas and liver. Further studies are required to determine the possible association between the brain and gastrointestinal dysfunctions in children with autistic disorder.

Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children

BACKGROUND

We investigated a consecutive series of children with chronic enterocolitis and regressive developmental disorder.

METHODS

12 children (mean age 6 years [range 3-10], 11 boys) were referred to a paediatric gastroenterology unit with a history of normal development followed by loss of acquired skills, including language, together with diarrhoea and abdominal pain. Children underwent gastroenterological, neurological, and developmental assessment and review of developmental records. Ileocolonoscopy and biopsy sampling, magnetic-resonance imaging (MRI), electroencephalography (EEG), and lumbar puncture were done under sedation. Barium follow-through radiography was done where possible. Biochemical, haematological, and immunological profiles were examined.

FINDINGS

Onset of behavioural symptoms was associated, by the parents, with measles, mumps, and rubella vaccination in eight of the 12 children, with measles infection in one child, and otitis media in another. All 12 children had intestinal abnormalities, ranging from lymphoid nodular hyperplasia to aphthoid ulceration. Histology showed patchy chronic inflammation in the colon in 11 children and reactive ileal lymphoid hyperplasia in seven, but no granulomas. Behavioural disorders included autism (nine), disintegrative psychosis (one), and possible postviral or vaccinal encephalitis (two). There were no focal neurological abnormalities and MRI and EEG tests were normal. Abnormal laboratory results were significantly raised urinary methylmalonic acid compared with age-matched controls (p=0.003), low haemoglobin in four children, and a low serum IgA in four children.

INTERPRETATION

We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers.

PiZZ alpha 1-antitrypsin deficiency in a 20-week fetus

Immunoperoxidase and electron microscopic studies of the liver of a 20-week fetus with PiZZ alpha 1-antitrypsin deficiency are described. The significance of the bile duct hypoplasia observed in the liver is discussed. The abnormal morphology of the jejunal mucosa is also described.

Coeliac disease: alpha-1-antitrypsin contents in jejunal mucosa before and after gluten-free diet

Biopsies of the jejunum from 10 patients suffering from coeliac disease were investigated by an immunohistochemical technique for alpha-I-antitrypsin. The biopsies obtained before treatment did not contain alpha-I-antitrypsin, but after a gluten-free diet alpha-I-antitrypsin was present in Paneth cells in the mucosal crypts. This finding suggests that the absence of alpha-I-antitrypsin in the jejunal mucosa might be a pathogenetic factor in coeliac disease.

Morphological identification of alpha-I-antitrypsin in the human small intestine

Alpha-I-antitrypsin immunoreactivity was demonstrated by immunofluorescence in epithelial cells of the normal human small intestine. Its presence was also confirmed in biopsies of patients with Crohn's disease. Specific fluorescence was observed in only four out of 14 adult patients with coeliac disease. These results implicate the human small intestinal epithelium as a possible source of alpha-I-antitrypsin. The absence of positive cells may have implications in the aetiology of coeliac disease.

Successful spleno-renal shunt and splenectomy in two patients with alpha-1-antitrypsin deficiency

Recent evidence suggests that the cirrhosis of alpha-1-antitrypsin deficiency is not invariably fatal as it was previously thought. Portal hypertension is often the major determinant of survival. The few reports of porta-systemic venous anastomosis in this disorder have shown poor results or uncertain outcome. Thus, doubts exist as to whether porta-systemic shunts should be performed in alpha-1-antitrypsin deficiency. Two patients with alpha-1-antitrypsin deficiency (PiZZ) and associated portal hypertension, cirrhosis, and hypersplenism underwent splenorenal shunt and splenectomy 8 yr ago, and both have done well. One of the patients has chronic severe headaches, diarrhea, exudative enteropathy, sinusitis, and hematuria, all uncommon in alpha-1-antitrypsin deficiency but possibly related to the antienzyme deficiency. She also has a higher trypsin inhibitory capacity than is generally reported in ZZ individuals. Based on the experience with these 2 patients, it appears that alpha-1-antitrypsin deficiency with cirrhosis is not a valid contraindication to the performance of a portasystemic shunt.

alpha 1-Antitrypsin-levels and phenotypes in Crohn's disease in the Netherlands

A group of 310 unrelated patients suffering from Crohn's disease has been screened for quantitative and electrophoretic variations of alpha 1-antitrypsin (alpha 1AT). A comparison was made betweeen patients and healthy controls. The distribution of electrophoretic alpha 1AT variants in the patients showed no significant deviation from the controls. The alpha 1AT quantities are significantly higher in the Crohn's disease population than in the controls.

Response of intestinal mucosa to gluten challenge in autistic subjects

Eight autistic patients with steatorrhoea, hypocalciuria, and alleged behavioural improvements on gluten restriction, were fed ordinary diets plus 20 g gluten/day for 4 weeks. None of the patients had any significant change in body-weight or bowel habit as a result of gluten challenge, nor were any histological abnormalities detected on jejunal biopsy. The data suggest that the steatorrhoea and hypocalciuria seen in some autistic subjects cannot be accounted for by the presence of coeliac disease. Furthermore, these patients should not be confined to gluten-free diets, unless rigorous behavioural studies demonstrate a statistically significant improvement in behaviour as a result of the diet, or deterioration during challenge.

The development of infantile autism

An account is given of how research over the last 30 years has led to progress in the delineation of the mechanisms involved in the genesis of the behaviour covered by the term ‘infantile autism’. The validity, nature, and basis of the syndrome are discussed with reference to treatment.