Determination of total, free and esterified short-chain fatty acid in human serum by liquid chromatography-mass spectrometry

Abstract

Background Short-chain fatty acids are primarily absorbed through the portal vein during lipid digestion, which is utilized as the energy source, as well as prevent type 2 diabetes and some cancers. However, reports on the determination of these short-chain fatty acids in human serum are limited. Methods Blood samples from human subjects ( n = 547, male/female = 246/301, age 58.85 ± 12.57) were collected. Saponification was applied to obtain total fatty acid. After derivatization by 2-nitrophenylhydrazine, fatty acid 4:0 and fatty acid 6:0 were measured by liquid chromatography-mass spectrometry. Results The developed method exhibited good linearity (R = 0.9996 for both). All the coefficients of variation of reproducibility and accuracy for fatty acid 4:0 and fatty acid 6:0 ranged 3.0%-6.1%, with the average recoveries of 87.8%-102.4% and 92.2%-98.2%, respectively. In all the samples, the concentration of fatty acid 4:0 (162.4 ± 76.4 μmol/L) was significantly higher than fatty acid 6:0 (2.0 ± 2.5 μmol/L, P < 0.001). Furthermore, the esterified form was predominant in both fatty acid 4:0 and fatty acid 6:0 (98.2% and 82.4% of total fatty acids, respectively). Besides, short-chain fatty acids showed no significant differences with regard to sex or age differences. Conclusion This developed liquid chromatography-mass spectrometry method is convenient and reliable, which might be useful for monitoring the variations of short-chain fatty acids in blood.

A straightforward LC-MS/MS analysis to study serum profile of short and medium chain fatty acids

“…The GC-MS/TOF was found to be a robust method to detect SMCFAs but in here its applicability was limited to a small number of samples, used for the determination of accuracy of the LC-MS/MS technique. The approach of LC-MS was driven by a shorter time of both analysis and sample preparation which theoretically can bypass the derivatization and the back-extraction steps used by other authors in either GC or LC [6,7,12,13]. Hence, a first approach was the detection of SMCFAs without derivatization [18].…”

“…Several GC-MS methods [6][7][8][9][10] were applied to measure SMCFAs in different matrices, but most of these are not sensitive enough and require time-consuming sample preparation and derivatization [11], which can influence their recovery drastically. This article was focused on the development of a LC-MS/MS technique with an effortless derivatization step [12][13][14][15][16][17] to detect SMCFAs physiological range in the serum of healthy volunteers and to shed light on the difficulty to correctly quantify their levels, by LC-MS, without chemical derivatization [18].…”

Short-chain fatty acids and intestinal inflammation in Multiple Sclerosis – Modulation of female susceptibility by microbial products?

“…Jakobsdottir and colleagues reported sex-speci c differences of blood SCFA concentrations (with lower SCFA concentrations in female subjects) in a study comparing patients with microscopic colitis and celiac disease (26). Another study did not nd sex-speci c differences when analyzing blood SCFA concentrations (27). As already mentioned, blood and fecal SCFA concentrations are not directly comparable.…”

“…Assuming that immunotherapies in MS exert anti-in ammatory effects also in the gastrointestinal tract, the intestinal microbiota (as indicated by Storm-Larsen et al for dimethylfumarate (27)) and subsequently intestinal SCFA production might be affected as well. Hence, the lack of a signi cant difference between RRMS patients and controls with regard to fecal SCFA concentrations in this study might also be explained by a drug effect.…”

Fecal markers in Multiple Sclerosis Sex makes the difference

“…In our study, median fecal acetate was 90.6% reduced in women. Yet, another Chinese study by Chen et al could not reproduce a sex-related difference when analyzing serum SCFA levels(32).…”