Introduction Diagnostic markers of necrotising enterocolitis (NEC) remain evasive. Stool short chain fatty acids (sSCFAs) are a product of bacterial fermentation of undigested carbohydrate and protein noted to alter in animal models of NEC. According to the Lawrence Hypothesis, they may be causative of NEC. We sought to correlate changes in sSCFAs over the first month of life in a cohort of preterm, very low birth weight infants with and without NEC.
Methods 56 sequentially recruited infants <32 weeks and <1.5Kg birth weight within week 1 of life. Stool samples taken once weekly for the first 4 weeks, analysed by gas chromatography-mass spectrometry (mcg/g wet weight). 11 individual acids were measured: acetate, lactate, isobutyrate, butyrate, isocaproate, caproate, isovalerate, valerate, octanoate, heptanoate and lactate. NEC was diagnosed by consultant, external collaborator and radiologist, using Bell’s Criteria.
Results N = 56 infants (83% recruitment). 20 developed ≥Bell’s 2a. 8 required surgery (5 ileostomy). Further clinical/demographical information can be found in abstract BEAT82431. There were no correlations between gestation, feed, NEC and sSCFAs. No significant differences were observed in weekly totals. Wide interquartile ranges were noted (Week 1: 20.9 ± 26; Week 2: 15.8 ± 19.1; Week 3: 13.2 ± 20.8; Week 4: 12 ± 22.9). Acetate and lactate dominated each sample, regardless of gestation, feed or NEC (p < 0.05). Subgroup analysis revealed significant differences in stage 2a and 3b NEC. Stage 2a showed higher concentrations of propionate in week 4 than week 3 (0.74 ± 6.45 Vs 0.15 ± 0.17, p = 0.05 MWU), and lower valerate in week 4 than 2 (0.00476 ± 0.012 Vs 0.0129 ± 0.028, p = 0.02 MWU). Stage 3b isobutyrate and heptanoate concentrations were significantly lower in week 4 than 3 (I: 0.007 ± 0.026 Vs 0.053 ± 0.09, p = 0.03; H: 0.011 ± 0.013Vs 0.023 ± 0.043, p = 0.03).
Conclusion Despite a wide variation in clinical status, the levels of sSCFAs remained remarkably consistent. Small yet significant differences in minor sSCFAs were seen in subgroup analysis in those with stage 2a and 3b NEC. Reasons for the high incidence of NEC require further investigation.