Determination of Short-Chain Fatty Acids in Blood Serum as Biomarkers of Renal Dysfunction

Abstract

Short-chain fatty acids (SCFAs), produced by the gut microbiota, play a crucial role in maintaining the immune status of a body. Chronic kidney diseases are associated with a reduction in microbial diversity in the gut and a disruption in SCFA production. In chronic kidney diseases, the level of SCFAs in the circulating blood decreases; so, the development of highly sensitive methods for determining SCFAs in serum is necessary. We have developed a method for determining SCFAs in serum and tested it in a comparative study of serum samples from healthy volunteers and patients with diagnosed chronic kidney diseases. The determination of SCFAs (acetic, propionic, butyric, valeric, caproic, iso-butyric, and iso-valeric acids) in blood serum was carried out by gas chromatography–mass spectrometry (GC–MS) and gas chromatography–tandem mass spectrometry (GC–MS/MS). The limits of detection for the investigated SCFAs by GC–MS range from 0.05 to 0.09 µg/mL, while the limits of detection by GC–MS/MS range from 0.002 to 0.007 µg/mL. In the serum samples of patients with chronic kidney diseases, the concentrations of all the investigated SCFAs were lower compared to the control group and fell below the limits of detection of the GC–MS method.