Probiotics and necrotizing enterocolitis

[Protective effect of Lactobacillus reuteri against oxidative stress in neonatal mice with necrotizing enterocolitis]

OBJECTIVE

To investigate the protective effect of L. reuteri DSM17938 strain against oxidative stress in a neonatal mouse model of necrotizing enterocolitis (NEC) and explore the possible mechanism.

METHODS

Ninety-six 10-day-old neonatal C57BL/6J mice were equally randomized into control group, NEC group, and NEC+ L. reuteri group. The pathological changes of the ileocecal intestinal tissue were evaluated with HE staining and double-blind pathological scoring. The mRNA and protein expressions of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the intestinal tissues were detected using quantitative real-time PCR and ELISA, respectively. Colorimetric assays were used to determine the activity of superoxide dismutase (SOD) and its inhibition rate, malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), and GSSG/ GSH ratio.

RESULTS

Compared with those in the control group, the neonatal mice in NEC group showed significant weight loss (P < 0.05), obvious intestinal injury, increased pathological scores (P < 0.05), increased expressions of TNF-α and IL-1β mRNA and proteins (P < 0.05), decreased SOD activity and inhibition rate, decreased GSH, and significantly increased MDA, GSSG, and GSSG/GSH ratios (P < 0.05). Treatment with L. reuteri obviously decreased the pathological scores, expressions of TNF-α and IL-1β (P < 0.05), MDA, GSSG, and GSSG/GSH ratio (P < 0.05), and significantly increased SOD activity, its inhibition rate, and GSH level in the mice with NEC, but the survival rate was not significantly different between NEC and L. reuteri-treated groups (P > 0.05).

CONCLUSIONS

L. reuteri DSM17938 can offer protection against NEC in mice by reducing oxidative stress and increasing antioxidant capacity of the intestinal tissue to suppress intestinal inflammations.

Recent Advances in Prevention and Therapies for Clinical or Experimental Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is one of the most severe diseases of preterm neonates and has a high mortality rate. With the development of inspection techniques and new biomarkers, the diagnostic accuracy of NEC is constantly improving. The most recognized potential risk factors include prematurity, formula-feeding, infection, and microbial dysbiosis. With further understanding of the pathogenesis, more effective prevention and therapies will be applied to clinical or experimental NEC. At present, such new potential prevention and therapies for NEC are mainly focused on the Toll-like receptor 4 inflammatory signaling pathway, the repair of intestinal barrier function, probiotics, antioxidative stress, breast-feeding, and immunomodulatory agents. Many new studies have changed our understanding of the pathogenesis of NEC and improve our approaches for preventing and treating of NEC each year. This review provides an overview of the recent researches focused on clinical or experimental NEC and highlights the advances made within the past 5 years toward the development of new potential preventive approaches and therapies for this disease.

Time to reintroduction of feeding in infants with nonsurgical necrotizing enterocolitis

BACKGROUND

For infants with necrotizing enterocolitis (NEC) treated nonoperatively, no consensus exists on the optimal fasting period prior to reintroducing feeds after NEC. We report our experience with early (<7days) and late (≥7days) refeeding in this population.

METHODS

A chart review of infants with NEC born between 2006 and 2016 was performed. Data elements include demographics, comorbidities, day of diagnosis, Bell's stage, recurrence, strictures, length of stay and mortality, and were grouped into early and late refeeding. T-tests were used for means and chi-squared tests for distribution of proportions. Linear and logistic regressions were used to further evaluate the association of length of stay, stricture, recurrence, and death with time to refeeding.

RESULTS

Of 228 NEC patients, 149(65%) were treated nonoperatively (Bell Stages I, IIA, IIB, IIIA). Eleven patients were excluded owing to never restarting feeds, largely secondary to early death. The early (n=40) and late refeeding (n=98) groups were not significantly different with regard to mean gestational age at birth, race, birth weight, day of life at NEC diagnosis, or cardiac disease. NEC Stage was significantly different (p<0.001). The late group had significantly more Stage IIB patients (p=.02), and the early group had more stage I patients (p=<0.01). After adjusting for Bell's stage, the odds of NEC recurrence, death, and the composite outcome of recurrence or stricture or death were not significantly different between early and late groups.

CONCLUSIONS

No standardized guidelines exist for restarting enteral nutrition following medical NEC. In patients managed nonoperatively, early reintroduction of feeding was not significantly associated with increased NEC recurrence, mortality, or stricture.

LEVEL OF EVIDENCE

Treatment Study - Level III.

Enteric serotonin and oxytocin: endogenous regulation of severity in a murine model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a gastrointestinal inflammatory disease of unknown etiology that may also affect the liver, causes a great deal of morbidity and mortality in premature infants. We tested the hypothesis that signaling molecules, which are endogenous to the bowel, regulate the severity of intestinal and hepatic damage in an established murine NEC model. Specifically, we postulated that mucosal serotonin (5-HT), which is proinflammatory, would exacerbate experimental NEC and that oxytocin (OT), which is present in enteric neurons and is anti-inflammatory, would oppose it. Genetic deletion of the 5-HT transporter (SERT), which increases and prolongs effects of 5-HT, was found to increase the severity of systemic manifestations, intestinal inflammation, and associated hepatotoxicity of experimental NEC. In contrast, genetic deletion of tryptophan hydroxylase 1 (TPH1), which is responsible for 5-HT biosynthesis in enterochromaffin (EC) cells of the intestinal mucosa, and TPH inhibition with LP-920540 both decrease the severity of experimental NEC in the small intestine and liver. These observations suggest that 5-HT from EC cells helps to drive the inflammatory damage to the gut and liver that occurs in the murine NEC model. Administration of OT decreased, while the OT receptor antagonist atosiban exacerbated, the intestinal inflammation of experimental NEC. Data from the current investigation are consistent with the tested hypotheses-that the enteric signaling molecules, 5-HT (positively) and OT (negatively) regulate severity of inflammation in a mouse model of NEC. Moreover, we suggest that mucosally restricted inhibition of 5-HT biosynthesis and/or administration of OT may be useful in the treatment of NEC.NEW & NOTEWORTHY Serotonin (5-HT) and oxytocin reciprocally regulate the severity of intestinal inflammation and hepatotoxicity in a murine model of necrotizing enterocolitis (NEC). Selective depletion of mucosal 5-HT through genetic deletion or inhibition of tryptophan hydroxylase-1 ameliorates, while deletion of the 5-HT uptake transporter, which increases 5-HT availability, exacerbates the severity of NEC. In contrast, oxytocin reduces, while the oxytocin receptor antagonist atosiban enhances, NEC severity. Peripheral tryptophan hydroxylase inhibition may be useful in treatment of NEC.

Necrotizing enterocolitis symposium: Epidemiology and early diagnosis

Despite decades of research on necrotizing enterocolitis (NEC), the outlook for infants afflicted by this devastating disease is all too often bleak. The aim of this symposium at the BAPS conference in Amsterdam was to highlight recent advances in the knowledge of the epidemiology and diagnosis of NEC. There were important contributions on the disease in the United Kingdom, both from a neonatal and from a surgical point of view, whereas colleagues from the Netherlands and elsewhere in Europe shared their insights into novel diagnostic tools, both biofluid and imaging based.

LEVEL OF EVIDENCE

Level V.

Current Research on the Epidemiology, Pathogenesis, and Management of Necrotizing Enterocolitis

Despite decades of research on necrotizing enterocolitis, we still do not fully understand the pathogenesis of the disease, or how to prevent or how to treat it. However, as a result of recent significant advances in the microbiology, molecular biology, and cell biology of the intestine of preterm infants and infants with necrotizing enterocolitis, there is some hope that research into this devastating disease will yield some important translation into effective prevention, more rapid diagnosis, and novel therapies.

Necrotizing enterocolitis: new insights into pathogenesis and mechanisms

Necrotizing enterocolitis (NEC) is the most frequent and lethal disease of the gastrointestinal tract of preterm infants. At present, NEC is thought to develop in the premature host in the setting of bacterial colonization, often after administration of non-breast milk feeds, and disease onset is thought to be due in part to a baseline increased reactivity of the premature intestinal mucosa to microbial ligands as compared with the full-term intestinal mucosa. The increased reactivity leads to mucosal destruction and impaired mesenteric perfusion and partly reflects an increased expression of the bacterial receptor Toll-like receptor 4 (TLR4) in the premature gut, as well as other factors that predispose the intestine to a hyper-reactive state in response to colonizing microorganisms. The increased expression of TLR4 in the premature gut reflects a surprising role for this molecule in the regulation of normal intestinal development through its effects on the Notch signalling pathway. This Review will examine the current approach to the diagnosis and treatment of NEC, provide an overview of our current knowledge regarding its molecular underpinnings and highlight advances made within the past decade towards the development of specific preventive and treatment strategies for this devastating disease.