Mortality and severe morbidity remain high in extremely preterm infants. Human milk-based nutrient fortifiers may prevent serious complications and death. We aimed to investigate whether supplementation with human milk-based fortifier (HMBF), as compared to bovine milk-based fortifier (BMBF), reduced the incidence of the composite outcome of necrotising enterocolitis (NEC), sepsis, and mortality in extremely preterm infants exclusively fed human milk. In this multicentre, randomised controlled trial at 24 neonatal units in Sweden, extremely preterm infants born between gestational week 22 + 0 and 27 + 6 fed exclusively human breast milk (mother's own and/or donor milk), were randomly assigned (1:1) to receive targeted fortification with either HMBF or BMBF. Randomisation was conducted before the enteral feeds reached 100 mL/kg/day, and was stratified by enrolment site, gestational age, singleton/twin, and sex. The allocation was concealed before inclusion, but after randomisation the study was not blinded for the clinical staff. For the NEC diagnosis, the study group was masked to an independent radiologist, and the final assessment of NEC and culture-proven sepsis was done by a blinded consensus panel review. The primary outcome was the composite of NEC stage II–III, culture-proven sepsis, and mortality from inclusion to discharge, no longer than postmenstrual week 44 + 0, in the intention-to-treat population (ClinicalTrials.gov, NCT03797157). Between February 21st, 2019, and May 21st, 2021, 229 neonates were randomly assigned (115 HMBF, 114 BMBF). After exclusion of one infant due to parents’ withdrawal of consent, 228 infants were included in the intention-to-treat analysis. Of the 115 infants assigned to HMBF, 41 (35.7%) fulfilled the criteria of either NEC, sepsis, or death, compared with 39 (34.5%) of 113 infants assigned to BMBF (OR 1.05, 95% CI 0.61–1.81, p = 0.86). Adverse events did not differ significantly between groups. Supplementation with HMBF, as compared with BMBF, did not reduce the incidence of the composite outcome of NEC, sepsis, or death. Our results do not support routine supplementation with HMBF as a nutritional strategy to prevent NEC, sepsis, or death in extremely preterm infants exclusively fed human milk. ALF grant, Prolacta Bioscience, 10.13039/501100004359 Swedish Research Council , and Research Council for Southeast Sweden.

Difference in human milk oligosaccharides (HMO) composition in breast milk may be one explanation why some preterm infants develop necrotizing enterocolitis (NEC) despite being fed exclusively with breast milk. The aim of this study was to measure the concentration of 15 dominant HMOs in breast milk during the neonatal period and investigate how their levels correlated to NEC, sepsis, and growth in extremely low birth weight (ELBW; <1000 g) infants who were exclusively fed with breast milk. Milk was collected from 91 mothers to 106 infants at 14 and 28 days and at postmenstrual week 36. The HMOs were analysed with high-performance anion-exchange chromatography with pulsed amperometric detection. The HMOs diversity and the levels of Lacto-N-difucohexaose I were lower in samples from mothers to NEC cases, as compared to non-NEC cases at all sampling time points. Lacto-N-difucohexaose I is only produced by secretor and Lewis positive mothers. There were also significant but inconsistent associations between 3′-sialyllactose and 6′-sialyllactose and culture-proven sepsis and significant, but weak correlations between several HMOs and growth rate. Our results suggest that the variation in HMO composition in breast milk may be an important factor explaining why exclusively breast milk fed ELBW infants develop NEC.

Necrotizing enterocolitis (NEC) is a devastating intestinal disease in preterm infants characterized by barrier disruption, intestinal microbial dysb

Lactobacillus reuteri DSM 17938 supplementation reduces morbidities in very low birth weight infants (<1500 g), while the effect on extremely low birth weight infants (ELBW, <1000 g) is still questioned. In a randomised placebo-controlled trial (ClinicalTrials.gov ID NCT01603368), head growth, but not feeding tolerance or morbidities, improved in L. reuteri-supplemented preterm ELBW infants. Here, we investigate colonisation with the probiotic strain in preterm ELBW infants who received L. reuteri DSM 17938 or a placebo from birth to postmenstrual week (PMW) 36. Quantitative PCR was used on 582 faecal DNA samples collected from 132 ELBW infants at one, two, three, and four weeks, at PMW 36, and at two years of age. Human milk oligosaccharides were measured in 31 milk samples at two weeks postpartum. At least 86% of the ELBW infants in the L. reuteri group were colonised with the probiotic strain during the neonatal period, despite low gestational age, high antibiotic pressure, and independent of infant feeding mode. Higher concentrations of lacto-N-tetraose, sialyl-lacto-N-neotetraose c, and 6′-sialyllactose in mother’s milk weakly correlated with lower L. reuteri abundance. Within the L. reuteri group, higher L. reuteri abundance weakly correlated with a shorter time to reach full enteral feeding. Female sex and L. reuteri colonisation improved head growth from birth to four weeks of age. In conclusion, L. reuteri DSM 17938 supplementation leads to successful colonisation in ELBW infants.

Background: Human milk oligosaccharides are complex, non-digestible carbohydrates that directly interact with intestinal epithelial cells to alter barrier function and host inflammation. Oligosaccharide composition varies widely between individual mothers, but it is unclear if this inter-individual variation has any impact on intestinal epithelial barrier function and gut inflammation. Methods: Human milk oligosaccharides were extracted from the mature human milk of four individual donors. Using an in vitro model of intestinal injury, the effects of the oligosaccharides on the intestinal epithelial barrier and select innate and adaptive immune functions were assessed. Results: Individual oligosaccharide compositions shared comparable effects on increasing transepithelial electrical resistance and reducing the macromolecular permeability of polarized (Caco-2Bbe1) monolayers but exerted distinct effects on the localization of the intercellular tight junction protein zona occludins-1 in response to injury induced by a human enteric bacterial pathogen Escherichia coli, serotype O157:H7. Immunoblots showed the differential effects of oligosaccharide compositions in reducing host chemokine interleukin 8 expression and inhibiting of p38 MAP kinase activation. Conclusions: These results provide evidence of both shared and distinct effects on the host intestinal epithelial function that are attributable to inter-individual differences in the composition of human milk oligosaccharides.