Absolute quantification of cholesteryl esters using liquid chromatography-tandem mass spectrometry uncovers novel diagnostic potential of urinary sediment
Urine has been utilized as a source of biomarkers in renal disease. However, urinary lipids have not attracted much attention so far. Here we studied urinary cholesteryl ester (CE) and its relevance in renal disease.Methods:
Quantitative analysis of CE molecular species in serum, urinary supernatant, and urinary sediment from patients with renal disease (N = 64) and non-renal disease (N = 23) was carried out using liquid chromatography-tandem mass spectrometry (LC–MS/MS) and deuterated CEs as internal standards.Result:s
Validation study showed good precision and accuracy of LC–MS/MS. Many CE species were detected in the urinary sediment and supernatant in the renal disease group, whereas only a few CE species were detected in the other group. In the renal disease group, the sum of the concentrations of all CE species showed a significant correlation between the sediment and the supernatant from urinary samples (r = 0.876, p < 0.001); however, the composition of CEs was significantly different between them. Further, the composition of CEs of the supernatant was similar to that of the serum.Conclusions:
Our LC–MS/MS analysis uncovered a distinct CE profile in urinary sediment from patients with renal disease, suggesting a possible contribution of CEs in urothelial cells to the development of renal disease.