Measurement of urinary sugars by hplc as a non invasive test of increased intestinal permeability in autistic children

الملخص EN

Objectives : Autism is found now to be more prevalent than childhood cancer, diabetes and Down Syndrome, affecting as many as 1 in each 500 children.

In autism, increased intestinal mucosa permeability is expected secondary to the “leaky gut” hypothesis or “opioid excess” hypothesis.

This study aimed at testing increased intestinal permeability in autistic children by using the standard convenient and non invasive lactulose/mannitol test which assesses mucosal integrity of the small bowel in children.

Methods: Fifty autistic children fulfilling all the DSM-IV research diagnostic criteria for Autistic Disorder were recruited from the specialist outpatient clinic for autism at Institute of Psychiatry Ain Shams University Hospitals.

Twenty children with normal intellectual functioning and with no personal or family current/past history of neuropsychiatric disorder were selected as a control group.

Severity of autism was assessed by the Childhood Autism Rating Scale (CARS).

All patients and controls were subjected to: 1) full history taking with emphasis on history of communication and behavioral development; 2) thorough clinical examination including evaluation of behavioral and communication skills of each child; 3) Wechsler Intelligence Scale- child version (WISC) to assess their intellectual level; and, 4) the sugar permeability test which was based on simultaneous oral administration of two sugars with different molecular size and absorption routs (lactulose and mannitol-L/M), then the urinary recovery of each molecule was estimated using the high performance liquid chromatography (HPLC) technique.

Results: There was a highly significant elevation of both lactulose recovery percentage and L/M recovery ratio, but not mannitol recovery percentage, in autistic children compared to controls.

A highly significant positive correlation between lactulose recovery percentage and L/M recovery ratio, and highly significant negative correlation between mannitol recovery percentage and L/M recovery ratio in all autistic children was found.

L/M recovery ratio is proposed as an indicator for assessing the severity of autism.

Conclusion: Elevation of urinary excretion of lactulose and hence L/M recovery ratio may help to identify the role of increased intestinal permeability as an etiopathogenic factor in autism.