Pediatric Health and GI Research

About the program

This program centers on a practical clinical question: can probiotics and other microbiome-directed approaches help children with gastrointestinal symptoms, and can they be studied safely in infants? The trials are led by Dr. J. Marc Rhoads of the Division of Gastroenterology in the Department of Pediatrics at UTHealth Houston, with statistical and data-management support from the Biostatistics/Epidemiology/Research Design (BERD) Core. Dr. Hessabi's roles have been Data Manager, including developing the trials' REDCap databases, and co-author on the papers that report their results.

The infant work began in 2011 with a National Institutes of Health R34 trial on the safety of Lactobacillus reuteri in healthy infants with colic. Beyond safety, its aims covered fecal calprotectin as a marker of gut inflammation, serum cytokines, circulating regulatory T cells, and the fecal microbiota. The results, published in The Journal of Pediatrics in 2017, come from a double-blind, placebo-controlled phase 1 safety and tolerability trial in breast-fed infants. A separate double-blind pilot tested hypoallergenic formula supplemented with Lactobacillus rhamnosus GG and was designed in part to learn how feasible recruitment and retention would be before any larger trial (World Journal of Gastrointestinal Pathophysiology, 2016).

A second line of work concerns gastrointestinal symptoms in children with autism spectrum disorder. A 2022 pilot study in the Journal of Pediatric Gastroenterology and Nutrition compared the fecal mycobiome, the community of fungi in the gut, across children with autism and GI symptoms, children with autism without GI symptoms, and typically developing children. From 2017 to 2025 Dr. Hessabi was also Data Manager for trials of the combination probiotic Bifidobacterium lactis BB-12 with Lactobacillus rhamnosus GG in children with autism, including an NIH-funded randomized, placebo-controlled study of safety and tolerability in children aged 4 to 15 years. Results from those trials are not summarized here.

The program also connects to the Jamaican autism research, where food allergies were studied alongside detoxification genes. Several of the studies below are small pilots designed to inform larger trials, and none of their findings is guidance for treating an individual child.

Key findings

1. 01

   In a double-blind, placebo-controlled trial of 20 breast-fed infants with colic, daily Lactobacillus reuteri DSM 17938 for 42 days produced no severe adverse events and appeared safe, including in infants with the low neutrophil counts that frequently coexist with colic. It did not significantly change crying time, plasma bicarbonate, or inflammatory biomarkers (The Journal of Pediatrics, 2017).

2. 02

   The same trial observed a placebo response of 66%, which the authors read as a sign that many infants with colic will have resolution within three weeks. In infants whose stool was dominated by gram-negative organisms such as Klebsiella, Proteus, and Veillonella, resolution of colic was associated with marked decreases in those organisms (The Journal of Pediatrics, 2017).

3. 03

   In a pilot trial of hypoallergenic formula with Lactobacillus rhamnosus GG, recruitment was slow, with about 66% of eligible infants willing to enroll, and 20 infants were randomized and analyzed. Crying and fussing time, fecal calprotectin, plasma cytokines, and regulatory T cells did not differ significantly between groups, and fecal microbial communities varied widely without apparent influence from the probiotic. The authors concluded that future U.S. trials of probiotic-supplemented formula must plan for difficult enrollment (World Journal of Gastrointestinal Pathophysiology, 2016).

4. 04

   A mycobiome pilot study of 50 children found no difference in overall fungal diversity between children with autism and GI symptoms, children with autism without GI symptoms, and typically developing children. Candida species were identified in 21%, 56%, and 25% of samples in those groups, a difference that was not statistically significant, and Candida did not correlate with behavioral or GI symptoms. The authors concluded that fungi are present at normal levels in the stool of children with autism and are not associated with gut inflammation (Journal of Pediatric Gastroenterology and Nutrition, 2022).

5. 05

   In age- and sex-matched Jamaican children with and without autism, neither food allergies nor glutathione S-transferase genes were associated with autism itself. Among children with autism, allergy to non-dairy foods was associated with higher restricted and repetitive behavior scores, and dairy allergy was associated with higher scores only in children with the GSTT1 DD genotype. The authors note the findings require replication in other populations (Journal of Autism and Developmental Disorders, 2024).

Collaborators

• Dr. J. Marc Rhoads (UTHealth McGovern Medical School)
• Dr. Yuying Liu (UTHealth)
• Dr. Nicole Fatheree (UTHealth)

Publications in this program

1. 2022·Journal of Pediatric Gastroenterology and Nutrition·23 citations

   Fungi: friend or foe? A mycobiome evaluation in children with autism and gastrointestinal symptoms

   Alookaran J, Liu Y, Auchtung TA, Tahanan A, Hessabi M, Asgarisabet P, et al.

2. 2017·Journal of Pediatrics·92 citations

   Lactobacillus reuteri for infants with colic: a double-blind, placebo-controlled, randomized clinical trial

   Fatheree NY, Liu Y, Taylor CM, Hoang TK, Cai C, Rahbar MH, et al.