Analysis of the metabolic profiles from faeces and plasma of children born very preterm

Abstract

Acute changes in the composition of the microbial flora can have a profound impact on the health of the host organism. The main objective of the study was to characterise the microbial metabolome in faecal matter and plasma from prematurely born infants and controls. Stool and plasma samples were collected from children aged 5 - 10 years who were born very preterm, (< 32 weeks gestation; n = 50) and control children in the same age group born at term (37 – 41 weeks; n = 50). The faecal samples were extracted and analysed using SPME-GC-MS and the extraction was carried out using two different temperatures; 37oC and 90oC. The metabolite profile of two extraction temperatures varied profoundly. The compounds that were statistically significant for 37oC included Butanoic acid, 3- methylbutanoic acid, methyl Isobutyl ketone, pentanoic acid, 5-methylthio pentaneniitrile and 4-ethylphenol. Butanoic acid, 3-methylbutanoic acid, pentanoic acid and 5-methylthio pentanenitrile were all elevated in children born preterm while others like methyl Isobutyl ketone, 4-ethylphenol, were found to be at lower concentrations in the preterm samples. For 90oC the list included decyl ether, tridecanal, hexanoic acid butyl ester, propyl decanoate and dimethyl trisulfide. Except for dimethyl trisulfide, all of the other compounds were found to be elevated in preterms. The plasma and faecal amino acid analysis was carried out for 40 samples (18 preterm and 22 terms) using UHPLC. The plasma amino acids concentrations (μmol/L) of various amino acids varied widely between the preterm and term plasma samples with arginine levels significantly lower in preterm compared to terms. The plasma arginine levels were also found to be correlated (R-square 0.1805, p=0.0891) with the insulin sensitivity data (Si) for the children born preterm, but not children born at term. The faecal amino acids levels were found to be low in preterm compared to the term children.