Safety and efficacy of Lactobacillus for preventing necrotizing enterocolitis in preterm infants

The Detrimental Effects of Peripartum Antibiotics on Gut Proliferation and Formula Feeding Injury in Neonatal Mice Are Alleviated with Lactobacillus rhamnosus GG

Peripartum antibiotics can negatively impact the developing gut microbiome and are associated with necrotizing enterocolitis (NEC). The mechanisms by which peripartum antibiotics increase the risk of NEC and strategies that can help mitigate this risk remain poorly understood. In this study, we determined mechanisms by which peripartum antibiotics increase neonatal gut injury and evaluated whether probiotics protect against gut injury potentiated by peripartum antibiotics. To accomplish this objective, we administered broad-spectrum antibiotics or sterile water to pregnant C57BL6 mice and induced neonatal gut injury to their pups with formula feeding. We found that pups exposed to antibiotics had reduced villus height, crypt depth, and intestinal olfactomedin 4 and proliferating cell nuclear antigen compared to the controls, indicating that peripartum antibiotics impaired intestinal proliferation. When formula feeding was used to induce NEC-like injury, more severe intestinal injury and apoptosis were observed in the pups exposed to antibiotics compared to the controls. Supplementation with the probiotic Lactobacillus rhamnosus GG (LGG) reduced the severity of formula-induced gut injury potentiated by antibiotics. Increased intestinal proliferating cell nuclear antigen and activation of the Gpr81-Wnt pathway were noted in the pups supplemented with LGG, suggesting partial restoration of intestinal proliferation by probiotics. We conclude that peripartum antibiotics potentiate neonatal gut injury by inhibiting intestinal proliferation. LGG supplementation decreases gut injury by activating the Gpr81-Wnt pathway and restoring intestinal proliferation impaired by peripartum antibiotics. Our results suggest that postnatal probiotics may be effective in mitigating the increased risk of NEC associated with peripartum antibiotic exposure in preterm infants.

Reducing Risk Factors for Necrotizing Enterocolitis: What Is the Recent Evidence and Biologic Plausibility Supporting Probiotics?

BACKGROUND

Development of necrotizing enterocolitis is multifactorial, with contributing factors that are unique to the preterm infant in the neonatal intensive care unit (NICU). The use of probiotics may reduce these risk factors.

PURPOSE

To evaluate evidence of biologic plausibility for probiotic supplementation to mitigate key risk factors implicated in the development of disease and show recent evidence of safety and effectiveness.

DATA SOURCES

A literature survey of electronic databases, including PubMed, Cochrane Database of Systematic Reviews, and CINAHL, was conducted.

STUDY SELECTION

Selection terms included "necrotizing enterocolitis," "probiotics," and "prematurity." Reviews that were included were full text, in English, and published in the last 5 years. Ten systematic reviews of randomized controlled trials were extracted from 749 records. Excluded were studies that used adjuncts to probiotics, such as lactoferrin or prebiotics, and studies of probiotics given antenatally.

DATA EXTRACTION

Two independent reviewers extracted data to AMSTAR 2, a critical appraisal tool for systematic reviews of randomized or nonrandomized studies of healthcare interventions.

RESULTS

All the reviews found statistically significant reductions in necrotizing enterocolitis rates after supplementation with probiotics. None of the reviews reported adverse effects.

IMPLICATION FOR PRACTICE AND RESEARCH

Probiotic supplementation with specific strains reduces risk for necrotizing enterocolitis. To advance probiotic use in the NICU, additional high-quality trials are needed to focus on specific strains or combinations of strains and to evaluate dosing and duration of treatment.Video Abstract available athttps://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx .

Gastrointestinal Microbiome and Multiple Health Outcomes: Umbrella Review

In recent years, there has been growing concern about the impact of the gastrointestinal microbiome on human health outcomes. To clarify the evidence for a link between the gastrointestinal microbiome and a variety of health outcomes in humans, we conducted an all-encompassing review of meta-analyses and systematic reviews that included 195 meta-analyses containing 950 unique health outcomes. The gastrointestinal microbiome is related to mortality, gastrointestinal disease, immune and metabolic outcomes, neurological and psychiatric outcomes, maternal and infant outcomes, and other outcomes. Existing interventions for intestinal microbiota (such as probiotics, fecal microbiota transplant, etc.) are generally safe and beneficial to a variety of human health outcomes, but the quality of evidence is not high, and more detailed and well-designed randomized controlled trials are necessary.

Identifying single-strain growth patterns of human gut microbes in response to preterm human milk and formula

The intestinal microbiota of the preterm neonate has become a major research focus, with evidence emerging that the microbiota influences both short and long-term health outcomes, in the neonatal intensive care unit and beyond. Similar to the term microbiome, the preterm gut microbiome is highly influenced by diet, specifically formula and human milk use. This study aims to analyze next-generation products including preterm formula, human milk-oligosaccharide term formula, and preterm breastmilk. We used a culture-based model to differentially compare the growth patterns of individual bacterial strains found in the human intestine. This model probed 24 strains of commensal bacteria and 8 pathobiont species which have previously been found to cause sepsis in preterm neonates. Remarkable differences between strain growth and culture pH were noted after comparing models of formulas and between human milk and formula. Both formula and human milk supported the growth of commensal bacteria; however, the formula products, but not human milk, supported the growth of several specific pathogenic strains. Computational analysis revealed potential connections between long-chain fatty acid and iron uptake from formula in pathobiont organisms. These findings indicate that there is a unique profile of growth in response to human milk and formula and shed light into how the infant gut microbiota could be influenced.

Abnormalities in microbial composition and function in infants with necrotizing enterocolitis: A single-center observational study

OBJECTIVE

To investigate the features and functions of the intestinal microbiota in neonates with necrotizing enterocolitis (NEC) in a single center in China.

METHODS

We collected clinical information and stool samples from 19 participants in our center, including 9 infants with necrotizing enterocolitis and 10 control infants. DNA was extracted from the samples, and 16S rRNA gene sequencing was used to analyse the participants' gut microbiota. Functional prediction was achieved using PICRUSt2.

RESULTS

Alpha diversity analysis found that similar levels of bacterial richness and diversity were found in the gut microbiota of infants with NEC and control infants (P = 0.1800), whereas beta diversity analysis suggested that the overall structures of the gut microbiota were significantly different (P = 0.0020). The Mann-Whitney U test of bacterial composition and abundance analysis revealed that the abundance levels of Proteobacteria (P = 0.03049) and Firmicutes (P = 0.01011) significantly differed between the two groups at the phylum level. Proteobacteria was the most abundant phylum in the NEC group. At the genus level, the abundance levels of Enterococcus (P = 0.0003), Streptococcaceae (P = 0.0109) and Lactobacillales (P = 0.0171) were significantly decreased in infants with NEC. Furthermore, the linear discriminant analysis effect size (LEfSe) method showed 12 bacterial taxa with significant differences in relative abundances in the two groups. Interestingly, members of Proteobacteria were enriched in NEC samples. In addition, functional prediction suggested that the microbial changes observed in infants with NEC resulted in a decline in galactose metabolism, the pentose phosphate pathway, fructose and mannose metabolism, amino sugar and nucleotide sugar metabolism, glycolysis/gluconeogenesis, starch and sucrose metabolism, and phosphotransferase system (PTS) pathways (P < 0.05).

CONCLUSIONS

Our study shows the compositional and functional alterations of the intestinal microbiota in NEC, which will help demonstrate the relationship between the gut microbiota and NEC pathogenesis.

Effects of Probiotics and Lactoferrin on Necrotizing Enterocolitis in Preterm Infants

Background

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in neonates. Despite intensive research, the etiology and pathophysiology of NEC is still obscure. Evidence from recent studies and meta-analyses showed a significant role of probiotics as a prophylactic measure in reducing NEC, sepsis, and mortality. However, obstacles against the generalization of the results still remain. The aim of the study was to evaluate the role of prophylactic administration of probiotics and lactoferrin in reducing the rate of NEC in preterm infants.

Methods

In this retrospective cohort study, all medical records of infants born with a birth weight of 1,500 g and less who were born between 2012 and 2017 were reviewed. The enrolled infants were divided into two groups: group 1 included infants born between January 2012 and August 2014, a period before probiotics were started in our unit, and group 2 included infants born between January 2014 and December 2017 after starting probiotics and lactoferrin. Multiple variables were collected including maternal data, neonatal data, and risk factors for NEC.

Results

Medical records of 284 infants who met our inclusion criteria were reviewed. Of the 284 infants, 134 were in group 1 and 150 infants were in group 2. There were no significant statistical differences between group 1 and group 2 in neonatal and maternal demographic data and clinical data. Of 134 infants who received probiotics and lactoferrin, 11 developed NEC, while 26 of the 150 infants in group 2 developed NEC, and the difference was statistically significant (p = 0.023).

Conclusion

Probiotics and lactoferrin given orally to very low birth weight preterm infants were associated with a decreased rate of NEC.

Key Technologies for Progressing Discovery of Microbiome-Based Medicines

A growing number of experimental and computational approaches are illuminating the “microbial dark matter” and uncovering the integral role of commensal microbes in human health. Through this work, it is now clear that the human microbiome presents great potential as a therapeutic target for a plethora of diseases, including inflammatory bowel disease, diabetes and obesity. The development of more efficacious and targeted treatments relies on identification of causal links between the microbiome and disease; with future progress dependent on effective links between state-of-the-art sequencing approaches, computational analyses and experimental assays. We argue determining causation is essential, which can be attained by generating hypotheses using multi-omic functional analyses and validating these hypotheses in complex, biologically relevant experimental models. In this review we discuss existing analysis and validation methods, and propose best-practice approaches required to enable the next phase of microbiome research.

Current Resources for Evidence-Based Practice, September 2020

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of “spin” in scientific reporting and its effect on summaries and syntheses of the literature and commentaries on reviews about early versus late amniotomy as part of labor induction protocols and the economic burden associated with maternal morbidity.

Probiotic Supplementation During the Perinatal and Infant Period: Effects on Gut Dysbiosis and Disease

The perinatal period is crucial to the establishment of lifelong gut microbiota. The abundance and composition of microbiota can be altered by several factors such as preterm delivery, formula feeding, infections, antibiotic treatment, and lifestyle during pregnancy. Gut dysbiosis affects the development of innate and adaptive immune responses and resistance to pathogens, promoting atopic diseases, food sensitization, and infections such as necrotizing enterocolitis (NEC). Recent studies have indicated that the gut microbiota imbalance can be restored after a single or multi-strain probiotic supplementation, especially mixtures of Lactobacillus and Bifidobacterium strains. Following the systematic search methodology, the current review addresses the importance of probiotics as a preventive or therapeutic tool for dysbiosis produced during the perinatal and infant period. We also discuss the safety of the use of probiotics in pregnant women, preterm neonates, or infants for the treatment of atopic diseases and infections.

Prophylactic antenatal N-Acetyl Cysteine administration combined with postnatal administration can decrease mortality and injury markers associated with necrotizing enterocolitis in a rat model

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of neonates, especially premature neonates. To date, there is no prophylactic treatment against NEC, except breast milk and slow increase in enteral feeding, and there is no antenatal prophylaxis.

AIMS

To assess possible protective effects of antenatal N-Acetyl Cysteine (NAC) against the intestinal pathophysiological changes associated with NEC in a rat model of NEC and against its associated mortality.

METHODS

Newborn Sprague-Dawley rats were divided into 5 groups: control (n = 33); NEC (n = 32)-subjected to hypoxia and formula feeding for 4 days to induce NEC; NEC-NAC (n = 34)-with induced NEC and concomitant postnatal NAC administration; NAC-NEC (n = 33)-born to dams treated with NAC for the last 3 days of pregnancy starting at gestational age of 18 days, and then subjected to induced NEC after birth; NAC-NEC-NAC (n = 36)-subjected to induced NEC with both prenatal and postnatal NAC treatment. At day of life 5, weight and survival of pups in the different groups were examined, and pups were euthanized. Ileal TNF-α, IL-6, IL-1β, IL-10, NFkB p65, iNOS and cleaved caspase 3 protein levels (western blot) and mRNA expression (RT-PCR) were compared between groups.

RESULTS

Pup mortality was significantly reduced in the NAC-NEC-NAC group compared to NEC (11% vs. 34%, P<0.05). Ileal protein levels and mRNA expression of all injury markers tested except IL-10 were significantly increased in NEC compared to control. These markers were significantly reduced in all NAC treatment groups (NEC-NAC, NAC-NEC, and NAC-NEC-NAC) compared to NEC. The most pronounced decrease was observed in the NAC-NEC NAC group.

CONCLUSIONS

Antenatal NAC decreases injury markers and mortality associated with NEC in a rat model. Antenatal administration of NAC may present a novel approach for NEC prophylaxis in pregnancies with risk for preterm birth.