Paneth cell ablation in the presence of Klebsiella pneumoniae induces necrotizing enterocolitis (NEC)-like injury in immature murine small intestine

Chunxian Zhang,David Bader,Lawrence S Prince,Steven J Mcelroy,Michael P Sherman,Jörn-Hendrik Weitkamp,James C Slaughter

doi:10.1242/dmm.009001

Chunxian Zhang, David Bader + Show 5 more

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https://doi.org/10.1242/dmm.009001

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Abstract

SUMMARYNecrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants. During NEC pathogenesis, bacteria are able to penetrate innate immune defenses and invade the intestinal epithelial layer, causing subsequent inflammation and tissue necrosis. Normally, Paneth cells appear in the intestinal crypts during the first trimester of human pregnancy. Paneth cells constitute a major component of the innate immune system by producing multiple antimicrobial peptides and proinflammatory mediators. To better understand the possible role of Paneth cell disruption in NEC, we quantified the number of Paneth cells present in infants with NEC and found that they were significantly decreased compared with age-matched controls. We were able to model this loss in the intestine of postnatal day (P)14-P16 (immature) mice by treating them with the zinc chelator dithizone. Intestines from dithizone-treated animals retained approximately half the number of Paneth cells compared with controls. Furthermore, by combining dithizone treatment with exposure to Klebsiella pneumoniae, we were able to induce intestinal injury and inflammatory induction that resembles human NEC. Additionally, this novel Paneth cell ablation model produces NEC-like pathology that is consistent with other currently used animal models, but this technique is simpler to use, can be used in older animals that have been dam fed, and represents a novel line of investigation to study NEC pathogenesis and treatment.

Highlights

Neonatal necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal mortality and morbidity in premature infants
Infants with surgical NEC lack Paneth cells Recently, we described a loss of mucus-filled goblet cells in infants with NEC compared with age-matched infants with spontaneous intestinal perforations (SIP) (McElroy et al, 2011)
Samples were stained with anti-lysozyme antibodies, phloxine/tartrazine and Alcian Blue/periodic acid Schiff (AB/PAS) to mark Paneth cells in multiple ways, and positive cells were counted per intestinal crypt by a single blinded investigator

Summary

Introduction

Neonatal necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal mortality and morbidity in premature infants. The exact pathophysiology of NEC is still unclear, several lines of clinical and basic science observations suggest that an exaggerated inflammatory response is involved. The leading hypothesis for pathophysiology of NEC is that intestinal bacteria that are normally restricted to the intestinal lumen somehow penetrate through the immature epithelial barrier and gain access to the epithelial cells and underlying lamina propria of the small intestine. This insult causes an exaggerated inflammatory response that is in turn followed by tissue destruction (Nanthakumar et al, 2000; Lin et al, 2008). The small intestinal epithelium is normally protected through an extensive defense network of innate immunity

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