An Exploratory Study of Increased Preterm Arginine INTake (PAINT18)

PAINT18 is a nutrition study focusing on the effect of arginine supplementation on immune function in preterm infants. The investigators will explore the effect of current intravenous feeding (parenteral nutrition (PN) formulations on blood arginine levels and the genes that are involved in body nutrition and fighting infection in premature babies. The investigators will also investigate the effect of supplementing arginine on these genes. The investigators will undertake a single centre exploratory physiological study in 24 very premature infants receiving PN. 16 of these infants will be supplemented with arginine. The investigators will record nutritional intake and routine biochemical testing data (which includes amino acid levels) collected over the first 30 days of life. The investigators will take blood for analysis at prespecified intervals for RNA sequencing, ammonia and IGF-1 levels. RNA sequencing findings will allow the investigators to describe the effect of arginine on gene activity in preterm infants The investigators hypothesise that arginine supplementation will result in changes in gene expression that are consistent with changes in T-cell function and associated inflammatory pathways.