An optimised monophasic faecal extraction method for LC-MS analysis and its application in gastrointestinal disease

Liquid chromatography coupled with mass spectrometry (LC-MS) metabolomic approaches are widely used to investigate underlying pathogenesis of gastrointestinal disease and mechanism of action of treatments. However, there is an unmet requirement to assess faecal metabolite extraction methods for large-scale metabolomics studies. Current methods often rely on biphasic extractions using harmful halogenated solvents, making automation and large-scale studies challenging. The present study reports an optimised monophasic faecal extraction protocol that is suitable for untargeted and targeted LC-MS analyses. The impact of several experimental parameters, including sample weight, extraction solvent, cellular disruption method, and sample-to-solvent ratio, were investigated. It is suggested that a 50 mg freeze-dried faecal sample should be used in a methanol extraction (1:20) using bead beating as the means of cell disruption. This is revealed by a significant increase in number of metabolites detected, improved signal intensity, and wide metabolic coverage given by each of the above extraction parameters. Finally, we addressed the applicability of the method on faecal samples from patients with Crohn’s disease (CD) and coeliac disease (CoD), two distinct chronic gastrointestinal diseases involving metabolic perturbations. Untargeted and targeted metabolomic analysis demonstrated the ability of the developed method to detect and stratify metabolites extracted from patient groups and healthy controls (HC), highlighting characteristic changes in the faecal metabolome according to disease. The method developed is, therefore, suitable for the analysis of patients with gastrointestinal disease and can be used to detect and distinguish differences in the metabolomes of CD, CoD, and HC

The effects of multivitamin supplementation on the composition and function of the gut microbiome in healthy adults

Abstract not currently available

Handgrip strength as a surrogate marker of lean mass and risk of malnutrition in paediatric patients

Background & Aims: The use of handgrip strength (HGS) as a proxy of nutritional status in sick children has not been studied. This study created HGS centile charts in healthy children and explored the utility of HGS z-scores as markers of body composition and screening of malnutrition risk in sick children. Methods: Data from 535 healthy children aged 5-16 years were used for the development of HGS centiles adjusted either for age or height. In 595 sick children, relationships between HGS z-scores with body composition, malnutrition risk (Paediatric Yorkhill Malnutrition Score-PYMS), length of hospital stay (LOS) and biomarkers of disease severity were explored. The use of HGS z-score to identify sick children in need of further dietetic assessment was investigated. Results: Children scoring at high malnutrition risk with PYMS had lower HGS z-scores for age (by 0.51 SD, p<0.001) and height (by 0.46 SD, p=0.001) than those who scored low. A HGS z-score at cut-offs of -0.81 SD and -1.2 SD for age and height, respectively, was predictive of need for dietetic intervention in sick children with sensitivity of 79% and 70% and specificity of 56% and 69%, respectively. HGS z-scores were predictive of fat free mass (FFM) in sick and healthy (all p<0.001) children, while fat mass was not. HGS z-scores were inversely related with plasma CRP (rho, age: -0.21; height: -0.23, both p=0.001). HGS was not predictive of LOS. Conclusion: HGS is predictive of FFM, could compliment assessment of malnutrition risk, and may help identify children for further dietetic intervention on admission to hospital

The impact of compliance during exclusive enteral nutrition on faecal calprotectin in children with Crohn’s disease

It remains unclear whether suboptimal response to exclusive enteral nutrition (EEN) in some children with Crohn's disease (CD) is explained by poor compliance. The current study measured faecal gluten immunogenic peptides (GIP), a biomarker of gluten intake, in 45 children (3–17 years) with CD, and explored associations with faecal calprotectin (FC) levels at 33 and 54 days of EEN. FC decreased in patients with undetectable GIP at both 33 and 54 days of EEN (mean decrease, 33 days: -743 mg/kg, 54 days: -1043 mg/kg, p < 0.001), but not in patients who had detectable levels. At EEN completion, patients with undetectable GIP had a lower FC by 717 mg/kg compared with patients with a positive GIP result (p = 0.042) and demonstrated a greater decline from baseline FC (-69% vs +5%, p = 0.011). Poorer response to EEN is explained in part by diminished compliance. Faecal GIP might be useful as proxy biomarker of EEN compliance