Neuroactive metabolites and bile acids are altered in extremely premature infants with brain injury

The gut microbiome has been associated with pathological neurophysiological evolvement in extremely premature infants suffering from brain injury. The exact underlying mechanism and its associated metabolic signatures in infants are not fully understood. To decipher metabolite profiles linked to neonatal brain injury, we investigated the longitudinal fecal and plasma metabolome of 51 extremely premature infants using LC-HRMS-based untargeted metabolomics. This was expanded by an investigation of bile acids and amidated bile acid conjugates in feces and plasma by LC-MS/MS-based targeted metabolomics. The resulting data was integrated with 16S rRNA gene amplicon gut microbiome profiles as well as patient cytokine, growth factor and T-cell profiles. We identified an early onset of differentiation in neuroactive metabolites and bile acids between infants with and without brain injury. We detected several bacterially-derived bile acid amino acid conjugates and secondary bile acids in the plasma already 3 days after delivery, indicating the early establishment of a metabolically active gut microbiome. These results give new insights into the early life metabolome of extremely premature infants.