Title: Mechanisms Affecting the Gut of Preterm Infants in Enteral feeding trials (MAGPIE)
Funder: Department of Health and Social Care

Abstract: The HTA have funded two nutritional interventional RCTs in premature infants <32 weeks gestation. These are the largest UK neonatal RCTs ever undertaken & offer a unique opportunity for mechanistic evaluation (ME) of interventions & serious disease: necrotising enterocolitis (NEC) a serious gut condition and late-onset sepsis (LOS), both of which may cause death or serious longterm morbidity. a)SIFT Speed of Increasing milk Feeds Trial: randomised to different rates of increase in feeds; primary outcome is survival without disability; secondary outcomes include NEC & LOS; currently successfully recruiting. b)ELFIN - Enteral Lactoferrin in Neonates; randomised to supplemental enteral lactoferrin (protein with anti-infective & immunomodulatory actions) or placebo; primary outcome is LOS; secondary outcomes include NEC; started June 2014. NEC affects 5–10% of these infants; ~30% require surgery or die. LOS affects <20% of whom 1 in 10 will die. NEC & LOS double the risk of major cognitive impairment such as cerebral palsy in survivors. This current proposal (MAGPIE) is for an EME funded ME of the trial interventions & outcomes (NEC/LOS) conducted in ~20% of infants recruited into SIFT/ELFIN. Participation in MAGPIE will not affect the main trial protocols & will use non-invasive biological specimens (urine, stool) & residual resected gut tissue (if surgery needed) from 480 infants. The principal actions of rate of milk feeding or lactoferrin in affecting rates of NEC/LOS will involve effects of gut microbes and metabolites (e.g. shortchain fatty acids, SCFA) that modulate aspects of host immune function. Premature infants rely on innate immunity whilst adaptive immunity develops. Recent evidence shows microbes & SCFA interact to affect differentiation of gut regulatory T cells (Arpaia et al. Nature 2013). Current hypotheses suggest that NEC/LOS are due to a dysregulated immune system in the face of gut dysbiosis (Neu et al NEJM 2012). Mechanistic study in premature infants is challenging due to ethical/practical constraints of invasive sampling (e.g blood). Our group has piloted & refined methodology for non-invasive collection & analysis of stool & urine (Embleton 2013). In the MAGPIE study microbiomic analysis will use next generation sequencing & metabolic activity measured by analysing volatile organic compounds (VOCs) & targeted mass spectrometry of stool/urine. Our work demonstrates associations between both stool microbes (Stewart et al. 2013) & VOCs (Garner et al. 2009) and subsequent NEC/LOS. MAGPIE will be the first study to combine these analyses within a neonatal RCT to enable ME of these clinical interventions (speed of feed increase & lactoferrin). Findings may lead to diagnostic or therapeutic advances which could be rapidly implemented as routine care if effective. We will explore differences in the micro/metabolome between cases/controls in the days preceding disease onset & the actions of trial interventions. Impacts of this research are multiple: translation of knowledge of mechanisms promoting gut health (especially if either main trial does not show clear benefit) may explain outcomes & offer alternate strategies to improve health. Microbiomic, metabolomic or tissue analyses may identify new non-invasive diagnostic or monitoring techniques, or preventative or treatment strategies (e.g. oral probiotics or antibiotics) for NEC or LOS, many of which could be implemented within a 3-5 year time period.

Lay abstract: Premature birth is increasing, associated with high rates of death, and worse physical & mental outcomes in survivors. Basic research in babies is difficult especially where blood samples are needed, and raises important ethical concerns. Over the last 20 years, respiratory support has improved meaning more babies now survive. Now, the most common causes of death after the first week are due to gut complications or infections. Necrotising enterocolitis (NEC) is a serious gut disease occurring in premature babies. NEC affects 1 in 10 babies born more than 8 weeks early; 1 in 3 of them require major surgery or die. Infections affect 1 in 5 premature babies, may cause death, and doubles the risk of long term problems such as cerebral palsy. Our group is already undertaking two NIHR funded studies (SIFT & ELFIN) to examine whether the way we feed premature babies (how quickly, and with what food supplements) affects rates of infection, NEC and brain outcomes: 1) SIFT - Speed of Increasing milk Feeds Trial 2) ELFIN - Enteral Lactoferrin in Neonates. Premature babies often take several days to tolerate milk feeds: SIFT compares a slightly faster to a slower rate of increases in the amount of milk, and will see if this affects rates of infections/NEC or brain outcome at 2 years age. Lactoferrin, a protein found in human & other animal milk, has anti-infective properties and is present in high levels in breast milk. Premature babies do not get much lactoferrin as they only get small amounts of milk, but we can add extra lactoferrin into the baby's milk feeds. The ELFIN study will see whether extra lactoferrin given with milk feeds reduces the number of babies who develop infections or NEC. The SIFT/ELFIN studies are the largest feeding studies ever, & will recruit >4500 premature babies from 30 hospitals. They will tell us whether these interventions affect NEC or sepsis, but not how they are working, nor will they help us understand what to do next if SIFT/ELFIN do not show clear effects. The interventions studied may improve outcomes by affecting gut bacteria or other effects on the baby's metabolism. The proposed MAGPIE study (Mechanisms Affecting the Gut of Preterm Infants in Enteral feeding trials) will explore how interventions work in the gut. The studies divide babies up (to receive specific treatments) in a random manner so that the treatments they receive will be evenly spread between the different study groups. MAGPIE will improve understanding of how the study interventions work in the gut, and the mechanisms that lead to gut disease or sepsis. Babies who are part of ELFIN can join MAGPIE. We will collect stool & urine samples, and analyse the patterns of germs & chemicals. This will tell us how the germs & chemicals relate to each other, how they are affected by the study (milk feeds or lactoferrin) or other interventions (e.g. antibiotics). If babies require an operation and have some gut removed we will examine any ‘left over’ gut tissue to see how their gut cells were affected. Because we are only using left-over samples there is no risk or discomfort to the babies. Some babies who were in the SIFT studied have already had stool and urine samples collected. The MAGPIE study is a unique opportunity to gain vital scientific knowledge about two important diseases in premature infants with high rates of death & serious morbidity. Our findings may help make the diagnosis earlier, and suggest what future treatments may optimise gut health or prevent serious disease in vulnerable infants.

Research activity codes: 5.1 PHARMACEUTICALS;5.7 PHYSICAL
Health categories: REPRODUCTIVE HEALTH AND CHILDBIRTH