Development of MRM Methods for Clinical Analysis of Urinary Myoglobin

摘要

Methodologies for the quantification of Mb in human urine samples using nanoLC-MRM-MS have been developed. These methods have been used to quantify uMb levels in cardiac surgery patients; some of which subsequently developed acute kidney injury (AKI). Label-free methods using LC-LTQ-MS for quantification of uMb were used to determine relative changes in uMb in patient samples (pre-surgery and post-surgery). Calibration curves for absolute quantification of uMb have been established using LC-TSQ-MS in three matrices: (1) neat, (2) BSA to model nephrotic urine, and (3) urine from healthy male subjects. Detection ranges from 0.32-200μg/L were achieved using our labeled approach compared to standard immunoassays (1-6μg/L). The nanoLC-LTQ-MS based relative quantification of uMb provided a robust approach for evaluating uMb abundance. These studies supported our hypothesis that the uMb levels increased in all patients' postcardiac surgery. Unexpectedly these data suggested a larger, sustained increase in post-surgery uMb in those patients that subsequently developed post-surgery AKI.