Identification of bacterial invasion in necrotizing enterocolitis specimens using fluorescent in situ hybridization

Maternal Nutritional Status and the Microbiome across the Pregnancy and the Post-Partum Period

Appropriate nutrition during pregnancy and the post-partum period is vital for both the mothers and their offspring. Both under- and over-nourished status may have important microbial implications on the maternal and infant gut microbiomes. Alterations in the microbiome can have implications for a person's risk of obesity and metabolic diseases. In this review, we examine alterations in the maternal gut, vaginal, placental, and milk microbiomes in the context of pre-pregnancy BMI, gestational weight gain, body composition, gestational diabetes, and maternal diet. We also investigate how the infant gut microbiome may be altered by these different parameters. Many of the microbial changes seen in under- and over-nourished states in birthing parents may result in long-term implications for the health of offspring. Differences in diet appear to be a major driver of the maternal and subsequently milk and offspring microbiomes. Further prospective longitudinal cohort studies are needed to examine nutrition and the microbiome to better understand its implications. Additionally, trials involving dietary interventions in child-bearing age adults should be explored to improve the mother and child's risks for metabolic diseases.

Gut dysbiosis during early life: causes, health outcomes, and amelioration via dietary intervention

The colonization and maturation of gut microbiota (GM) is a delicate and precise process, which continues to influence not only infancy and childhood but also adulthood health by affecting immunity. However, many perinatal factors, including gestational age, delivery mode, antibiotic administration, feeding mode, and environmental and maternal factors, can disturb this well-designed process, increasing the morbidity of various gut dysbiosis-related diseases, such as type-1-diabetes, allergies, necrotizing enterocolitis, and obesity. In this review, we discussed the early-life colonization and maturation of the GM, factors influencing this process, and diseases related to the disruption of this process. Moreover, we focused on discussing dietary interventions, including probiotics, oligosaccharides, nutritional supplementation, and exclusive enteral nutrition, in ameliorating early-life dysbiosis and diseases related to it. Furthermore, possible mechanisms, and shortcomings, as well as potential solutions to the drawbacks of dietary interventions, were also discussed.

Role of IgA in the early-life establishment of the gut microbiota and immunity: Implications for constructing a healthy start

Colonization and maturation of the gut microbiota (GM) during early life is a landmark event that fundamentally influences the (early) immunity and later-life health of various mammals. This is a delicate, systematic process that is biologically actively regulated by infants and their mothers, where (secretory) IgA, an important regulator of microbes found in breast milk and generated actively by infants, may play a key role. By binding to microbes, IgA can inhibit or enhance their colonization, influence their gene expression, and regulate immune responses. IgA dysfunction during early life is associated with disrupted GM maturation and various microbe-related diseases, such as necrotizing enterocolitis and diarrhea, which can also have a lasting effect on GM and host health. This review discusses the process of early GM maturation and its interaction with immunity and the role of IgA (focusing on milk secretory IgA) in regulating this process. The possible application of this knowledge in promoting normal GM maturation processes and immune education has also been highlighted.

Expressions of Fib, IL-12 in Serum of Neonatal Necrotizing Enterocolitis and Their Correlation with Clinicopathological Features

Background:

To investigate the expressions of fibrinogen (Fib) and Interleukin-12 (IL-12) in serum of neonatal necrotizing enterocolitis (NEC), and to analyze the correlation between the two and their relationship with clinicopathological features.

Methods:

Forty two children with NEC treated in Xuzhou Children’s Hospital, Xuzhou Medical University Xuzhou, China from 2016–2019 were selected as an observation group and 40 children who underwent physical examination at the same period as a control group. The expression levels of Fib and IL-12 in the serum of two groups were detected by ELISA. The correlation between Fib and IL-12 in the observation group and the correlation among the expressions of Fib, IL-12, the clinicopathological features and common examination indexes of the children with NEC were investigated by Pearson correlation analysis.

Results:

The levels of Fib and IL-12 in the serum of the children in observation group were significantly higher than those in the control group were (P<0.05). There was a significant positive correlation between the levels of Fib and IL-12 in the serum of the children in observation group (P<0.05). The expression levels of Fib, IL-12 were not significantly correlated with sex and age of NEC children, but correlated with vomiting, diarrhea, bloody stool and bradycardia in NEC children (P<0.05). Fib and IL-12 were positively correlated with erythrocyte level (P<0.05) and negatively correlated with platelet level.

Conclusion:

The expressions of Fib and IL-12 in the serum of NEC children can objectively predict the severity of NEC.

Exploring the Role of Gut Bacteria in Health and Disease in Preterm Neonates

The mortality rate of very preterm infants with birth weight <1500 g is as high as 15%. The survivors till discharge have a high incidence of significant morbidity, which includes necrotising enterocolitis (NEC), early-onset neonatal sepsis (EONS) and late-onset neonatal sepsis (LONS). More than 25% of preterm births are associated with microbial invasion of amniotic cavity. The preterm gut microbiome subsequently undergoes an early disruption before achieving bacterial maturation. It is postulated that bacterial gut colonisation at birth and postnatal intestinal dysbacteriosis precede the development of NEC and LONS in very preterm infants. In fact, bacterial colonization patterns in preterm infants greatly differ from term infants due to maternal chorioamnionitis, gestational age, delivery method, feeding type, antibiotic exposure and the environment factor in neonatal intensive care unit (NICU). In this regard, this review provides an overview on the gut bacteria in preterm neonates' meconium and stool. More than 50% of preterm meconium contains bacteria and the proportion increases with lower gestational age. Researchers revealed that the gut bacterial diversity is reduced in preterm infants at risk for LONS and NEC. Nevertheless, the association between gut dysbacteriosis and NEC is inconclusive with regards to relative bacteria abundance and between-sample beta diversity indices. With most studies show a disruption of the Proteobacteria and Firmicutes preceding the NEC. Hence, this review sheds light on whether gut bacteria at birth either alone or in combination with postnatal gut dysbacteriosis are associated with mortality and the morbidity of LONS and NEC in very preterm infants.

The Role of Glycosaminoglycans in Protection from Neonatal Necrotizing Enterocolitis: A Narrative Review

Necrotizing enterocolitis, a potentially fatal intestinal inflammatory disorder affecting primarily premature infants, is a significant cause of morbidity and mortality in neonates. While the etiology of the disease is, as yet, unknown, a number of risk factors for the development of necrotizing enterocolitis have been identified. One such risk factor, formula feeding, has been shown to contribute to both increased incidence and severity of the disease. The protective influences afforded by breastfeeding are likely attributable to the unique composition of human milk, an extremely potent, biologically active fluid. This review brings together knowledge on the pathogenesis of necrotizing enterocolitis and current thinking on the instrumental role of one of the more prominent classes of bioactive components in human breast milk, glycosaminoglycans.

Molecular epidemiology of Clostridium neonatale and its relationship with the occurrence of necrotizing enterocolitis in preterm neonates

Clostridia—especially Clostridium butyricum—are among the taxa most frequently identified from stool samples of preterm neonates with necrotizing enterocolitis (NEC). Recently, Clostridium neonatale has also been detected from epidemic cases, but using a culture-based approach we were unable to confirm this discovery in a local cohort. In order to investigate this link by a molecular approach, a specific rpoB-based quantitative real-time PCR was developed to detect C. neonatale directly from patients' stool specimens. Design of this rpoB-based quantitative real-time PCR was based on the genomic analysis of seven clinical isolates of C. neonatale. It was tested on stool samples from 88 preterm neonates with necrotizing enterocolitis and 71 matched controls. C. neonatale was significantly more prevalent in stools from preterm neonates with necrotizing enterocolitis than in controls (respectively 30/88 (34%) versus 9/71 (13%); p 0.003). Whole-genome analysis also allowed the identification of three genomic clusters of C. neonatale. This clustering was associated with a geographical location regardless of isolation from the NEC or control, suggesting asymptomatic carriage. Although less prevalent than C. butyricum in our cohort, C. neonatale is significantly associated with the occurrence of necrotizing enterocolitis.

Multidisciplinary evaluation of Clostridium butyricum clonality isolated from preterm neonates with necrotizing enterocolitis in South France between 2009 and 2017

The association between Clostridium species identification from stool samples in preterm neonates and the occurrence of necrotizing enterocolitis has been increasingly reported. To confirm the specific impact of Clostridium butyricum in this pathology, selective culture procedure was used for Clostridia isolation. Whole-genome analysis was employed to investigate genomic relationships between isolates. Stool samples from present study, as well as from previously investigated cases, were implicated including 88 from preterm neonates with necrotizing enterocolitis and 71 from matched controls. Quantitative real-time polymerase chain reaction was performed to evaluate the presence of C. butyricum from stools of new cases. Clostridium species prevalence isolated by culture was compared between patients with necrotizing enterocolitis and controls. By combining results of both culture and quantitative polymerase chain reaction methods, C. butyricum was significantly more frequent in stool samples from preterm neonates with necrotizing enterocolitis than in controls. Whole-genome analysis of 81 genomes including 58 neonates' isolates revealed that cases were clustered depending on geographical origin of isolation. Controls isolates presented genomic relations with that of patients suggesting a mechanism of asymptomatic carriage. Overall, this suggests an epidemiology comparable to that observed in Clostridium difficile colitis in adults.

Regulation of ROS-NF-κB axis by tuna backbone derived peptide ameliorates inflammation in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common life-threatening gastrointestinal disease encountered in the premature infant. It has been shown that the intercellular reactive oxygen species (ROS) generation activated by lipopolysaccharide involved in the nuclear factor kappa B (NF-κB) activation and pathogenesis of NEC. Here, we report that an antioxidant peptide from tuna backbone protein (APTBP) reduces the inflammatory cytokines transcription and release. APTBP directly scavenges the free radical through 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) assay. In addition, APTBP reduces the intracellular ROS level, exhibiting an antioxidant activity within cells. Remarkably, gavage with APTBP attenuates the phenotype of NEC in the mice model. Mechanically, the NF-κB activation, together with the expression of inflammatory cytokines are decreased significantly when intracellular ROS are eliminated by APTBP. Therefore, our findings demonstrated that an antioxidant peptide, APTBP, ameliorates inflammation in NEC through attenuating ROS-NF-κB axis.

Dysregulation of miR-431 and target gene FOXA1 in intestinal tissues of infants with necrotizing enterocolitis

The level of microRNA (miR)-431 was found to be markedly up-regulated in intestinal tissue of necrotizing enterocolitis (NEC). The objective of this study was to identify the target gene of miR-431 and to investigate the role of the miR-431-FOXA1 axis in the pathophysiology of NEC. The target gene of miR-431 was identified by in silico target prediction bioinformatics, luciferase assay, and Western blotting. Effects of miR-431 on downstream expression signals, cell proliferation, and apoptosis were investigated by overexpression in Caco-2 cells upon stimulation by LPS or lipoteichoic acid (LTA). FOXA1 was identified as the target gene of miR-431. Overexpression of miR-431 in Caco-2 cells significantly inhibited FOXA1, ESRRG, and HNF4A and activated IL-6, LGR5, NFKB2, PLA2G2A, PRKCZ, and TNF. IL-8 and - 10 were enhanced when costimulated with LPS or LTA. These potential downstream genes were also significantly dysregulated in primary NEC tissues compared with surgical-control tissues. Overexpression of miR-431 significantly decreased proliferation and increased apoptosis of Caco-2 cells. A proposed network of miR-431-FOXA1 interaction with LPS and LTA receptors demonstrates dysregulation of transcription factors, inflammatory mediators, epithelium tight junction regulators, and cell proliferation and apoptosis signals. The miR-431-FOXA1 axis could in part be responsible for the intensification of the inflammatory response in NEC tissues and contribute to the proinflammatory pathophysiology.-Wu, Y. Z., Chan, K. Y. Y., Leung, K. T., Lam, H. S., Tam, Y. H., Lee, K. H., Li, K., Ng, P. C. Dysregulation of miR-431 and target gene FOXA1 in intestinal tissues of infants with necrotizing enterocolitis.

Nutritional strategies and gut microbiota composition as risk factors for necrotizing enterocolitis in very-preterm infants

Background: The pathophysiology of necrotizing enterocolitis (NEC) remains poorly understood.Objective: We assessed the relation between feeding strategies, intestinal microbiota composition, and the development of NEC.Design: We performed a prospective nationwide population-based study, EPIPAGE 2 (Etude Epidémiologique sur les Petits Ages Gestationnels), including preterm infants born at <32 wk of gestation in France in 2011. From individual characteristics observed during the first week of life, we calculated a propensity score for the risk of NEC (Bell's stage 2 or 3) after day 7 of life. We analyzed the relation between neonatal intensive care unit (NICU) strategies concerning the rate of progression of enteral feeding, the direct-breastfeeding policy, and the onset of NEC using general linear mixed models to account for clustering by the NICU. An ancillary propensity-matched case-control study, EPIFLORE (Etude Epidémiologique de la flore), in 20 of the 64 NICUs, analyzed the intestinal microbiota by culture and 16S ribosomal RNA gene sequencing.Results: Among the 3161 enrolled preterm infants, 106 (3.4%; 95% CI: 2.8%, 4.0%) developed NEC. Individual characteristics were significantly associated with NEC. Slower and intermediate rates of progression of enteral feeding strategies were associated with a higher risk of NEC, with an adjusted OR of 2.3 (95% CI: 1.2, 4.5; P = 0.01) and 2.0 (95% CI: 1.1, 3.5; P = 0.02), respectively. Less favorable and intermediate direct-breastfeeding policies were associated with higher NEC risk as well, with an adjusted OR of 2.5 (95% CI: 1.1, 5.8; P = 0.03) and 2.3 (95% CI: 1.1, 4.8; P = 0.02), respectively. Microbiota analysis performed in 16 cases and 78 controls showed an association between Clostridium neonatale and Staphylococcus aureus with NEC (P = 0.001 and P = 0.002).Conclusions: A slow rate of progression of enteral feeding and a less favorable direct-breastfeeding policy are associated with an increased risk of developing NEC. For a given level of risk assessed by propensity score, colonization by C. neonatale and/or S. aureus is significantly associated with NEC. This trial (EPIFLORE study) was registered at clinicaltrials.gov as NCT01127698.