Growing evidence suggests a link between enteric bacteria and the central and enteric nervous systems; the gut-brain axis. Dysbiosis of the gut microflora influences these interactions and plays an important role in the pathophysiology of functional gastrointestinal and nervous system disorders1.
Modulation of the balance of gut microbes through dietary intervention, particularly the use of probiotics and fibre, can affect production of short chain fatty acids (SCFAs), the end products of microbial fermentation. SCFAs positively influence host metabolism by promoting energy homeostasis, regulating immune responses and epithelial cell growth, and promoting the functioning of the central and peripheral nervous systems2.
To facilitate understanding of the complex interplay between diet, host-gut microbiota and human health, quantitative analysis of SCFAs in faecal samples is often used to monitor the efficacy of gut-health interventions. Due to the volatility of SCFAs, LCMS analysis is preferred over GCMS, however accurate quantitation is hampered by the lack of commercially available internal standards (IS) to compensate for matrix effects prevalent in biological samples.
Han et al recently reported an MS-probe and stable isotope coding method for the accurate quantitation of SCFAs in human faeces3. This method uses 12C/13C6-3-nitrophenylhydrazine to quantitatively convert SCFAs to their 3-nitrophenylhydrazones to increase their analysis sensitivity. Isotope label coding is enabled using 13C6-3NPH to create an IS for each SCFA.
We have extended this methodology for analysis of SCFAs in other types of biological samples, including digesta and plasma, and will demonstrate applications in human studies and animal trials.