Necrotizing enterocolitis (NEC) remains the leading cause of gastrointestinal morbidity and mortality in premature infants. Human and animal studies suggest a role for Paneth cells in NEC pathogenesis. Paneth cells play critical roles in host-microbial interactions and epithelial homeostasis. The ramifications of eliminating Paneth cell function on the immature host-microbial axis remains incomplete. Paneth cell function was depleted in the immature murine intestine using chemical and genetic models, which resulted in intestinal injury consistent with NEC. Paneth cell depletion was confirmed using histology, electron microscopy, flow cytometry, and real time RT-PCR. Cecal samples were analyzed at various time points to determine the effects of Paneth cell depletion with and without Klebsiella gavage on the microbiome. Deficient Paneth cell function induced significant compositional changes in the cecal microbiome with a significant increase in Enterobacteriacae species. Further, the bloom of Enterobacteriaceae species that occurs is phenotypically similar to what is seen in human NEC. This further strengthens our understanding of the importance of Paneth cells to intestinal homeostasis in the immature intestine.

Eosinophilic esophagitis is characterized by dense infiltration of the esophageal epithelium with eosinophils, typically accompanied by dysphagia. Effective therapies include the use of topical and systemic steroids as well as elimination diets. No previous reports have described the use of montelukast in the management of pediatric eosinophilic esophagitis. We retrospectively reviewed the charts of all patients with eosinophilic esophagitis followed in our pediatric center between 2000 and 2009. Those treated with montelukast were studied in detail. Study outcome was clinical response rate, defined by symptom (not histologic) improvement. Twenty-one patients with eosinophilic esophagitis were identified. Eight patients were maintained on montelukast (range 4-10 mg daily) after confirming the diagnosis of eosinophilic esophagitis histologically and failing to respond to a trial of proton pump inhibitor therapy. Three of eight patients had a clinical response (one had complete response and two with partial response) that could be attributed to montelukast. Four other patients responded clinically, but other therapies were concomitantly implemented. No side effects were reported with montelukast treatment with a mean follow-up duration of 32 months. Five patients had remained on montelukast therapy at the time of the final follow-up. Montelukast has minimal risk of adverse reactions compared with steroid therapy and may offer clinical relief in a small subset of children with eosinophilic esophagitis. Histologic response could not be verified in this study. Prospective studies, using higher montelukast doses, may potentially play a role and should be considered for future investigation.

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