Breast-feeding is associated with fewer comorbidities in very-low-birth-weight (VLBW) preterm infants. Bronchopulmonary dysplasia (BPD) of VLBW infants is a multifactorial pathology in which nutritional aspects may be of special importance. The aim of this study is to determine, in a cohort of VLBW infants, whether breast milk nutrition is associated with a reduced prevalence and severity of BPD. A retrospective study was conducted to record the intake of mother’s own milk (MOM), pasteurised donor human milk or preterm formula milk in the first 2 weeks of postnatal life of 566 VLBW newborns at our hospital during the period January 2008–December 2021. After applying the relevant exclusion criteria, data for 489 VLBW infants were analysed; 195 developed some degree of BPD. Moderate or severe BPD is associated with less weight gain. Moreover, the preferential ingestion of breast milk in the first and second postnatal weeks had effects associated with lower OR for BPD, which were statistically demonstrable for mild (OR 0·16; 95 % CI 0·03, 0·71) and severe (OR 0·08; 95 % CI 0·009, 0·91) BPD. Breast-feeding during the first weeks of postnatal life is associated with a reduced prevalence of BPD, which is frequently associated with less weight gain as a result of greater respiratory effort with greater energy expenditure.

We assessed the effectiveness of lyophilised banked human milk (HM) as a fortifier to feed very-low-birth-weight infants (VLBWI). This study aimed to evaluate the safety and tolerability of HM with HM lyophilisate as an additive compared with the standard additive (cows’ milk protein). In this phase I double-blind randomised controlled clinical trial, set in the intensive and intermediate care units of a tertiary hospital, forty VLBWI were enrolled and allocated into two groups: HM plus HM lyophilisate (LioNeo) or HM plus commercial additive (HMCA). The inclusion criteria were preterm infants, birth weight 750–1500 g, small or adequate for gestational age, exclusively receiving donor HM, volume ≥ 100 ml/kg per d and haemodynamically stable. Participants were followed up for 21 consecutive days. The primary outcome measures were necrotising enterocolitis (NEC), late-onset sepsis (LOS), death, gastrointestinal (GI) bleeding or perforation, diarrhoea, regurgitation, vomiting and abdominal distension. The LioNeo and HMCA groups had similar weights at baseline. The regression models showed no differences between the groups in terms of the primary outcomes. Diarrhoea, GI perforation, NEC and LOS were absent in the LioNeo group (one LOS and one NEC in the HMCA group). Multiple regression analysis with the total volume of milk as a covariate did not show significant differences. The lyophilisation of donor HM was considered safe and tolerable for use in stable haemodynamically VLBWI.

Early life nutrition fundamentally influences neonatal development and health. Human milk oligosaccharides (HMO) are key components of breast milk but not standard infant formula that support the establishment of the newborn gut microbiota. Using an artificial rearing system, our objective was to test the effect of two HMO on the whole body and organ growth, adiposity, glucose tolerance and faecal microbiota in young rat pups. From postnatal days 4 to 21, Sprague–Dawley rats were randomised to receive one of: (1) CTR (rat milk substitute); (2) 2′FL (CTR + 1·2 g/l 2′-fucosyllactose); (3) 3′SL (CTR + 1·2 g/l 3′-sialyllactose) and (4) 2′FL + 3′SL (CTR + 0·6 g/l 2′-FL + 0·6 g/l 3′-SL). Body weight (BW), bowel movements and food intake were monitored daily, faecal samples collected each week and oral glucose tolerance, body composition and organ weight measured at weaning. No significant differences were observed between groups in growth performance, body composition, organ weight and abundance of dominant faecal microbes. A decreased relative abundance of genus Proteus in week 1 faecal samples and Terrisporobacter in week 3 faecal samples (P < 0·05) was suggestive of a potential pathogen inhibitory effect of 3′SL. Longitudinal changes in the faecal microbiota of artificially reared suckling rats were primarily governed by age (P = 0·001) and not affected by the presence of 2′-FL and/or 3′-SL in rat milk substitutes (P = 0·479). Considering the known protective effects of HMO, further investigation of supplementation with these and other HMO in models of premature birth, extremely low BW or malnutrition may show more pronounced outcomes.

Necrotising enterocolitis (NEC) is a devastating gastrointestinal disease of prematurity that typically develops after the administration of infant formula, suggesting a link between nutritional components and disease development. One of the most significant complications that develops in patients with NEC is severe lung injury. We have previously shown that the administration of a nutritional formula that is enriched in pre-digested Triacylglyceride that do not require lipase action can significantly reduce the severity of NEC in a mouse model. We now hypothesise that this ‘pre-digested fat (PDF) system’ may reduce NEC-associated lung injury. In support of this hypothesis, we now show that rearing newborn mice on a nutritional formula based on the ‘PDF system’ promotes lung development, as evidenced by increased tight junctions and surfactant protein expression. Mice that were administered this ‘PDF system’ were significantly less vulnerable to the development of NEC-induced lung inflammation, and the administration of the ‘PDF system’ conferred lung protection. In seeking to define the mechanisms involved, the administration of the ‘PDF system’ significantly enhanced lung maturation and reduced the production of reactive oxygen species (ROS). These findings suggest that the PDF system protects the development of NEC-induced lung injury through effects on lung maturation and reduced ROS in the lung and also increases lung maturation in non-NEC mice.

Neonates with CHD are at increased risk of developing necrotising enterocolitis due to mesenteric hypoperfusion. Necrotising enterocolitis results in repeated feed interruptions contributing to poor growth during the early post-operative phase. Poor weight gain and longer hospital stay are risk factors for death in neonates with CHD. Abdominal radiography is used as a diagnostic tool for necrotising enterocolitis; however, its utility is limited in the early stages of necrotising enterocolitis when pneumatosis intestinalis is absent. Calprotectin is a neutrophil activation biomarker, and elevated levels are evident in inflammatory diseases such as necrotising enterocolitis. The aim of this study was to determine whether there is a correlation between faecal calprotectin concentration and gut inflammation in neonates with CHD. This prospective single-centre study recruited newly diagnosed term patients with duct-dependent CHD between March 2018 and March 2019. Faecal calprotectin concentrations were measured in post-surgical patients using enzyme-linked immunosorbent assay methods. A total of 30 patients were included in the analysis. Calprotectin concentration for patients who developed necrotising enterocolitis was 3528 µg/g compared with 390 µg/g without, compared with 1339 µg/g in patients with suspected necrotising enterocolitis (p = 0.0001). Patients with suspected necrotising enterocolitis had a significantly longer length of hospital stay, on average 18 days longer compared to patients without necrotising enterocolitis (p = 0.03). Faecal calprotectin concentrations may reflect severity of gut inflammation in neonates with CHD. Suspected necrotising enterocolitis contributes to longer days nil by mouth and an increase in length of hospital stay.

Probiotics are being used increasingly in pregnant women, whereas the efficiency on pregnancy outcomes is yet lacking. PubMed, Embase and the Cochrane Library were searched. Relative risks (RR) or weighted mean differences (WMD) with 95 % CI were employed to calculate the summary outcomes. A total of eighteen randomised controlled trials (RCT) including 4356 pregnant women were eligible. The summary RR indicated that probiotic supplementation was associated with a significant decrease in the risk of atopic eczema (RR 0·68; 95 % CI 0·58, 0·81; P < 0·001) and eczema (RR 0·79; 95 % CI 0·68, 0·91; P = 0·002) without significant heterogeneity. Probiotic supplementation was associated with a prolonged gestational age (WMD 0·09; 95 % CI 0·04, 0·15; P = 0·001) with insignificant heterogeneity, whereas no significant effect was exerted on birth weight (P = 0·851). The risks of death (RR 0·34; 95 % CI 0·13, 0·91; P = 0·031) and necrotising enterocolitis (NEC) (RR 0·38; 95 % CI 0·18, 0·81; P = 0·012) were significantly reduced in pregnant women receiving probiotics without evidence of heterogeneity. These findings suggested that probiotics in pregnant women were beneficial for atopic eczema, eczema, gestational age, death and NEC.

Necrotising enterocolitis (NEC) is a devastating disease that typically affects formula-fed premature infants, suggesting that dietary components may influence disease pathogenesis. TAG are the major fat components of infant formula, and their digestion requires pancreatic lipases, which may be naturally deficient in premature neonates. We hypothesise that NEC develops partly from the accumulation of incompletely digested long-chain TAG-containing unsaturated fatty acids within the intestinal epithelial cells, leading to oxidative stress and enterocyte damage. We further hypothesise that the administration of a formula that contains reduced TAG (‘pre-digested fat’) that do not require lipase action may reduce NEC severity. To test these hypotheses, we induced NEC in neonatal mice using three different fat formulations, namely ‘standard fat’, ‘pre-digested fat’ or ‘very low fat’, and determined that mice fed ‘standard fat’ developed severe NEC, which was significantly reduced in mice fed ‘pre-digested fat’ or ‘very low fat’. The expression level of the critical fat-digesting enzyme carboxyl ester lipase was significantly lower in the newborn compared with older pups, leading to impaired fat digestion. The accumulation of mal-digested fat resulted in the significant accumulation of fat droplets within the intestinal epithelium of the distal ileum, resulting in the generation of reactive oxygen species and intestinal inflammation. Strikingly, these changes were prevented in pups fed ‘pre-digested fat’ or ‘very low fat’ formulas. These findings suggest that nutritional formula containing a pre-digested fat system may overcome the natural lipase deficiency of the premature gut, and serve as a novel approach to prevent NEC.

Infants with CHD are at increased risk of necrotising enterocolitis, which can interfere with the achievement of adequate nutrition and, ultimately, growth and development. Necrotising enterocolitis is classified by severity as suspected, confirmed, and advanced. We sought to quantify the incidence of all types of necrotising enterocolitis among infants who underwent surgery, with a particular focus on suspected necrotising enterocolitis. This is a retrospective review of all infants <6 months of age who underwent cardiac surgery during 2012 and 2013 at Children’s Hospital Colorado. We examined the hospital course of 265 hospitalisations (n=251 patients) and found 18 patients (19 hospitalisations) with suspected necrotising enterocolitis and 16 patients (16 hospitalisations) with confirmed or advanced necrotising enterocolitis. Single-ventricle physiology, lower weight, and younger age were associated with necrotising enterocolitis. Patients with all types of necrotising enterocolitis experienced prolonged length of hospital stay. We found suspected necrotising enterocolitis to be as common as confirmed necrotising enterocolitis, and it frequently occurred early in the post-operative course. We speculate that suspected necrotising enterocolitis may often be overlooked in research owing to a reliance on billing codes. Nevertheless, suspected necrotising enterocolitis poses a substantial barrier to post-operative progression of the CHD patient, as does confirmed necrotising enterocolitis. Following the diagnosis of all types of necrotising enterocolitis, there was wide variability in practice patterns. In response to this variability, we developed care guidelines for the diagnosis and treatment of necrotising enterocolitis in this population.

Infectious diarrhoea is a worldwide problem in newborns. Optimal bacterial colonisation may enhance gut maturation and protect against pathogenic bacteria after birth. We hypothesised that lactic acid bacteria (LAB) administration prevents pathogen-induced diarrhoea in formula-fed newborns. Newborn caesarean-delivered, colostrum-deprived term piglets on parenteral nutrition for the first 15 h, were used as models for sensitive newborn infants. A commercially available probiotic strain, Lactobacillus paracasei F19 (LAP, 2·6×108 colony-forming units (CFU)/kg per d) and a novel LAB isolate, Pediococcus pentosaceus (PEP, 1·3×1010 CFU/kg per d), were administered for 5 d with or without inoculation of the porcine pathogen, Escherichia coli F18 (F18, 1010 CFU/d). This resulted in six treatment groups: Controls (n 9), LAP (n 10), PEP (n 10), F18 (n 10), F18–LAP (n 10) and F18–PEP (n 10). The pathogen challenge increased diarrhoea and density of F18 in the intestinal mucosa (P<0·05). LAB supplementation further increased the diarrhoea score, relative to F18 alone (P<0·01). Intestinal structure and permeability were similar among groups, whereas brush border enzymes were affected in variable intestinal regions with decreased activities in most cases after F18 and LAB inoculation. Bacterial density in colon mucosa increased after F18 inoculation (P<0·05) but was unaffected by LAB supplementation. In colon contents, acetic and butyric acids were increased by PEP (P<0·05). The LAB used in this study failed to reduce E. coli-induced diarrhoea in sensitive newborn pigs. In vulnerable newborns there may be a delicate balance among bacterial composition and load, diet and the host. Caution may be required when administering LAB to compromised newborns suffering from enteric infections.

Infants born with low birth weights (<2500 g, LBW), accounting for about 15 % of newborns, have a high risk for postnatal growth failure and developing the metabolic syndromes such as type 2 diabetes, CVD and obesity later in life. Improper nutrition provision during critical stages, such as undernutrition during the fetal period or overnutrition during the neonatal period, has been an important mediator of these metabolic diseases. Considering the specific physiological status of LBW infants, nutritional intervention and optimisation during early life merit further attention. In this review, the physiological and metabolic defects of LBW infants were summarised from a nutritional perspective. Available strategies for nutritional interventions and optimisation of LBW infants, including patterns of nutrition supply, macronutrient proportion, supplementation of amino acids and their derivatives, fatty acids, nucleotides, vitamins, minerals as well as hormone and microbiota manipulators, were reviewed with an aim to provide new insights into the advancements of formulas and human-milk fortifiers.

The aim of the study was to determine whether routine probiotic supplementation (RPS) with Lactobacillus rhamnosus GG (LGG) or Lactobacillus acidophilus +Lactobacillus bifidum is associated with reduced risk of necrotising enterocolitis (NEC)≥Stage II in preterm neonates born at ≤32 weeks’ gestation. We conducted a retrospective cohort study on the effect of probiotic supplementation in very low birth weight infants in our neonatal unit by comparing two periods: before and after supplementation. The incidence of NEC≥Stage II, late-onset sepsis and all-cause mortality was compared for an equal period ‘before’ (Period I) and ‘after’ (Period II) RPS with LGG or L. acidophillus+L. bifidum. Multivariate logistic regression analysis was conducted to adjust for relevant confounders. The study population was composed of 261 neonates (Period I v. II: 134 v. 127) with comparable gestation duration and birth weights. In <32 weeks, we observed a significant reduction in NEC≥Stage II (11·3 v. 4·8 %), late-onset sepsis (16 v. 10·5 %) and mortality (19·4 v. 2·3 %). The benefits in neonates aged ≤27 weeks did not reach statistical significance. RPS with LGG or L. acidophillus+L. bifidum is associated with a reduced risk of NEC≥Stage II, late-onset sepsis and mortality in preterm neonates born at ≤32 weeks’ gestation.

Intestinal barrier integrity is a prerequisite for homeostasis of mucosal function, which is balanced to maximise absorptive capacity, while maintaining efficient defensive reactions against chemical and microbial challenges. Evidence is mounting that disruption of epithelial barrier integrity is one of the major aetiological factors associated with several gastrointestinal diseases, including infection by pathogens, obesity and diabetes, necrotising enterocolitis, irritable bowel syndrome and inflammatory bowel disease. The notion that specific probiotic bacterial strains can affect barrier integrity fuelled research in which in vitro cell lines, animal models and clinical trials are used to assess whether probiotics can revert the diseased state back to homeostasis and health. This review catalogues and categorises the lines of evidence available in literature for the role of probiotics in epithelial integrity and, consequently, their beneficial effect for the reduction of gastrointestinal disease symptoms.

Necrotising enterocolitis (NEC) is a common disease in premature infants characterised by intestinal ischaemia and necrosis. The only effective preventative strategy against NEC is the administration of breast milk, although the protective mechanisms remain unknown. We hypothesise that an abundant human milk oligosaccharide (HMO) in breast milk, 2′-fucosyllactose (2′FL), protects against NEC by enhancing intestinal mucosal blood flow, and we sought to determine the mechanisms underlying this protection. Administration of HMO-2′FL protected against NEC in neonatal wild-type mice, resulted in a decrease in pro-inflammatory markers and preserved the small intestinal mucosal architecture. These protective effects occurred via restoration of intestinal perfusion through up-regulation of the vasodilatory molecule endothelial nitric oxide synthase (eNOS), as administration of HMO-2′FL to eNOS-deficient mice or to mice that received eNOS inhibitors did not protect against NEC, and by 16S analysis HMO-2′FL affected the microbiota of the neonatal mouse gut, although these changes do not seem to be the primary mechanism of protection. Induction of eNOS by HMO-2′FL was also observed in cultured endothelial cells, providing a link between eNOS and HMO in the endothelium. These data demonstrate that HMO-2′FL protects against NEC in part through maintaining mesenteric perfusion via increased eNOS expression, and suggest that the 2′FL found in human milk may be mediating some of the protective benefits of breast milk in the clinical setting against NEC.

Human milk decreases the risk of necrotising enterocolitis (NEC), a severe gastrointestinal disease that occurs in 5–10 % of preterm infants. The prebiotic and immune-modulatory effects of milk oligosaccharides may contribute to this protection. Preterm pigs were used to test whether infant formula enriched with α1,2-fucosyllactose (2'-FL, the most abundant oligosaccharide in human milk) would benefit gut microbial colonisation and NEC resistance after preterm birth. Caesarean-delivered preterm pigs were fed formula (Controls, n 17) or formula with 5 g/l 2'-FL (2'-FL, n 16) for 5 d; eight 2'-FL pigs (50 %) and twelve Controls (71 %) developed NEC, with no difference in lesion scores (P=0·35); 2'-FL pigs tended to have less anaerobic bacteria in caecal contents (P=0·22), but no difference in gut microbiota between groups were observed by fluorescence in situ hybridisation and 454 pyrosequencing. Abundant α1,2-fucose was detected in the intestine with no difference between groups, and intestinal structure (villus height, permeability) and digestive function (hexose absorption, brush border enzyme activities) were not affected by 2'-FL. Formula enrichment with 2'-FL does not affect gut microbiology, digestive function or NEC sensitivity in pigs within the first few days after preterm birth. Milk 2'-FL may not be critical in the immediate postnatal period of preterm neonates when gut colonisation and intestinal immunity are still immature.

Necrotising enterocolitis (NEC) is one of the most frequent and fatal intestinal disorders in preterm infants and has very limited treatment options. Breast-fed infants are at a 6–10-fold lower NEC risk than formula-fed infants, and we have previously shown that human milk oligosaccharides (HMO) improved survival and reduced pathology in a rat NEC model. The HMO disialyllacto-N-tetraose (DSLNT) was most effective, and sialylation was shown to be essential for its protective effect. Galacto-oligosaccharides (GOS), currently added to some infant formula, but not containing sialic acid, had no effect. In addition to DSLNT, our previous work also showed that the neutral HMO fraction, which contains high concentrations of 2′-fucosyllactose (2′FL), slightly improved pathology scores. Here, we assessed the in vivo efficacy of 2′FL, as well as of GOS that we enzymatically sialylated (Sia-GOS). Neonatal rats were randomised into the following study groups – dam-fed (DF), formula-fed (FF), FF containing pooled HMO (10 mg/ml), GOS (8 mg/ml), Sia-GOS (500 µm) or 2′FL (2 mg/ml) – and subjected to the established NEC protocol. The DF and HMO groups had the lowest pathology scores with mean values of 0·67 (sd 0·34) and 0·90 (sd 0·47), respectively. The FF group had significantly elevated pathology scores of 2·02 (sd 0·63). Although the addition of GOS to the formula had no protective effect and generated scores of 2·00 (sd 0·63), the addition of Sia-GOS or 2′FL significantly lowered pathology scores to 1·32 (sd 0·56) (P<0·0034) and 1·43 (sd 0·51) (P<0·0040), respectively. The results warrant further studies to investigate the underlying mechanisms and to assess safety and efficacy in human neonates.