There is near‐global consensus that all newborns be given parenteral vitamin K₁ (VK₁) at birth as prophylaxis against VK deficiency bleeding (VKDB). Breastmilk has a low VK content and cases of late VKDB are reported in exclusively breastmilk‐fed preterm infants despite VK prophylaxis at birth. To assess the prevalence of functional VK insufficiency in preterm infants based on elevated under‐γ‐carboxylated (Glu) species of Gla proteins, factor II (PIVKA‐II), and osteocalcin (GluOC), synthesized by liver and bone, respectively. Prospective, multicenter, observational study in preterm infants born <33 weeks' gestation. Blood samples and dietary history were collected before hospital discharge, and after discharge at 2–3 months’ corrected age. Outcome measures were serum VK₁, PIVKA‐II, and %GluOC (GluOC as a percentage of the sum of GluOC plus GlaOC) compared between exclusively breastmilk‐fed and formula/mixed‐fed infants after discharge. After discharge, breastmilk‐fed babies had significantly lower serum VK₁ (0.15 vs. 1.81 μg/L), higher PIVKA‐II (0.10 vs. 0.02 AU/ml) and higher %GluOC (63.6% vs. 8.1%) than those receiving a formula/mixed‐feed diet. Pre‐discharge (based on elevated PIVKA‐II), only one (2%) of 45 breastmilk‐fed infants was VK insufficient. After discharge, eight (67%) of 12 exclusively breastmilk‐fed babies were VK insufficient versus only one (4%) of 25 formula/mixed‐fed babies. Preterm infants who remain exclusively or predominantly human breastmilk‐fed after neonatal unit discharge are at high risk of developing subclinical VK deficiency in early infancy. Routine postdischarge VK₁ supplementation of breastfed infants to provide intakes comparable to those from formula milks should prevent this deficiency.

Despite increasing knowledge on microRNAs, their role in the pathogenesis of neonatal encephalopathy remains to be elucidated. Herein, we identify let-7b-5p as a significant microRNA in neonates with moderate to severe encephalopathy from dried blood spots using next generation sequencing. Validation studies using Reverse Transcription and quantitative Polymerase Chain Reaction on 45 neonates showed that let-7b-5p expression was increased on day 1 in neonates with moderate to severe encephalopathy with unfavourable outcome when compared to those with mild encephalopathy. Mechanistic studies performed on glucose deprived cell cultures and the cerebral cortex of two animal models of perinatal brain injury, namely hypoxic-ischaemic and intrauterine inflammation models confirm that let-7b-5p is associated with the apoptotic Hippo pathway. Significant reduction in neuronal let-7b-5p expression corresponded with activated Hippo pathway, with increased neuronal/nuclear ratio of Yes Associated Protein (YAP) and increased neuronal cleaved caspase-3 expression in both animal models. Similar results were noted for let-7b-5p and YAP expression in glucose-deprived cell cultures. Reduced nuclear YAP with decreased intracellular let-7b-5p correlated with neuronal apoptosis in conditions of metabolic stress. This finding of the Hippo-YAP association with let-7b needs validation in larger cohorts to further our knowledge on let-7b-5p as a biomarker for neonatal encephalopathy.

Background: Hypoxic-ischemic encephalopathy (HIE) is associated with brain injury in newborns and may lead to disability or death. Mild therapeutic hypothermia (TH) is an effective neuroprotective intervention and an established standard of care in western countries. The gut microbiome, the genomic and physicochemical contribution of the gut microbiota, serves important functions and is increasingly recognized as a major influencer on development. The impact of HIE and TH on the evolving gut microbiota of the newborn remains to be elucidated. Objective: The objective of this study was to carry out an exploratory study on the effects of HIE and TH on the gut microbiome in term neonates. Methods and Results: Stool samples were obtained from 28 newborns with HIE (median age 68 h) undergoing TH on the neonatal unit (HIE TH group), with a follow-on stool sample available for 20 of these babies (median age 151 h). For comparison, a single stool specimen was obtained from 19 healthy newborns on the postnatal ward (median age 34 h). The microbiota composition was determined using established microbial DNA extraction and 16S rRNA gene sequencing methodology. There was no difference in the mode of delivery or the method of feeding the newborns, once established, between the 2 groups. All the infants in the HIE TH group had received antibiotics compared to only one of the controls. A lower α-diversity, quantified by the Shannon diversity index, was noted in the microbiota of the HIE TH group in comparison to the control group. The HIE TH group had a higher mean relative abundance (MRA) of facultative anaerobes and aerobes such as Staphylococcus species and a lower MRA of strict anaerobes, such as members of the Bacteroides genus, compared to the control. Also, there was a significant reduction in the MRA of the genus Bifidobacterium in the HIE TH group. Although the mode of delivery exerts a profound influence on the gut microbiota of the newborn, distance-based redundancy analysis showed that TH may exert an independent influence. This study could not determine the independent contribution of the use of antibiotics or the neonatal intensive care unit environment. Conclusion: In this study, we demonstrate an alteration in the microbiota composition in newborns undergoing TH for HIE.

Hypoxic-ischaemic encephalopathy (HIE) is an important cause of morbidity and mortality globally. Although mild therapeutic hypothermia (TH) may improve outcomes in selected babies, the mechanism of action is not fully understood. A proteomics discovery study was carried out to analyse proteins in the plasma of newborns with HIE. Proteomic analysis of plasma from 22 newborns with moderate-severe HIE that had initially undergone TH, and relative controls including 10 newborns with mild HIE who did not warrant TH and also cord blood from 10 normal births (non-HIE) were carried out using the isobaric Tandem Mass Tag (TMT^®) 10plex^TM labelling with tandem mass spectrometry. A total of 7818 unique peptides were identified in all TMT10plex^TM samples, translating to 3457 peptides representing 405 proteins, after applying stringent filter criteria. Apart from the unique protein signature from normal cord blood, unsupervised analysis revealed several significantly regulated proteins in the TH-treated moderate-severe HIE group. GO annotation and functional clustering revealed various proteins associated with glucose metabolism: the enzymes fructose-bisphosphate aldolase A, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate mutase 1, phosphoglycerate kinase 1, and pyruvate kinase PKM were upregulated in newborns with favourable (sHIE+) outcomes compared to newborns with unfavourable (sHIE−) outcomes. Those with favourable outcomes had normal MR imaging or mild abnormalities not predictive of adverse outcomes. However, in comparison to mild HIE and the sHIE− groups, the sHIE+ group had the additional glucose metabolism-related enzymes upregulated, including triosephosphate isomerase, α-enolase, 6-phosphogluconate dehydrogenase, transaldolase, and mitochondrial glutathione reductase. In conclusion, our plasma proteomic study demonstrates that TH-treated newborns with favourable outcomes have an upregulation in glucose metabolism. These findings may open new avenues for more effective neuroprotective therapy.