Development Of a Gc-Ms Method for Urinary Short-Chain Fatty Acids Quantification: Differences and Potential Indicators in Nafld and Healthy Individuals

Abstract

AbstractNon-alcoholic fatty liver disease (NAFLD), characterized by aberrant lipid metabolism within hepatocytes, exhibits a progressively rising incidence globally. Research has unveiled a correlation between short-chain fatty acids (SCFAs) and lipid metabolism. However, the intricate relationship between SCFAs and NAFLD remains underexplored. This study aimed to quantify urinary SCFAs in NAFLD patients and to assess the potential associations among SCFA levels and types, the severity of NAFLD, and relevant clinical indicators. Therefore, a novel high-performance gas chromatography-mass spectrometry method was developed to analyze seven SCFAs in human urine, with optimized extraction conditions. The results showed that NAFLD patients had significantly lower urinary concentrations of acetic, valeric, and hexanoic acids, as well as total SCFAs, with greater reductions in moderate-to-severe cases (p< 0.05). In NAFLD group, high-density lipoprotein was inversely correlated with propionic and isobutyric acids, while serum cholesterol and triglycerides showed negative associations with isobutyric, valeric, and hexanoic acids. Direct bilirubin positively correlated with valeric acid, γ-glutamyl transferase with acetic and propionic acids, as well as the total SCFAs, and alkaline phosphatase with isobutyric and isovaleric acids. Blood urea nitrogen exhibited a positive correlation with butyric acid exclusively in healthy individuals. Receiver operating characteristic curve analysis showed that acetic, valeric, and hexanoic acids have potential clinical values as diagnostic biomarkers for NAFLD. This study established a robust methodology and revealed significant associations between urinary SCFAs and NAFLD. These findings provide novel insights into the potential diagnostic biomarkers and therapeutic targets for NAFLD.

Note:
Funding declaration: This study were supported by the National Natural Science Foundation of China[grant number 82273684]; Medical Key Discipline Program of Wuxi Health Commission[grant number CXTD2021004]; Wuxi Municipal Health Commission Youth Project[grant number Q202338].

Conflict of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Ethical Approval: This study was approved by the Ethics Committee of Nanjing Medical University. Written informed consent was obtained from all participants.

Keywords: Keywords: Short-chain fatty acid, gas chromatography-mass spectrometry, non-alcoholic fatty liver disease