The simultaneous quantification of candidate serum biomarker peptides for hypertensive disorders of pregnancy

Abstract

Background Hypertensive disorders of pregnancy are defined as syndromes characterized by high blood pressure that develop after 20 weeks of pregnancy. The pathogenesis of hypertensive disorders of pregnancy has not been fully elucidated, and the most effective treatment is the termination of pregnancy. Therefore, methods for an early predictive diagnosis should be developed to rescue both the mother and the child. Methods Previously, we explored the serum peptides whose concentration varied specifically between patients with hypertensive disorders of pregnancy and normal pregnant women using peptidomics analysis and identified seven candidate marker peptides. To quantify the marker peptides more reliably, we attempted to quantify these peptides simultaneously by multiple reaction monitoring using liquid chromatography/tandem mass spectrometry (LC-MRM/MS). Non-labelled and stable isotope-labelled forms of the seven peptides were synthesized as standards, and the multiple reaction monitoring transitions for their quantification were determined. Results As the retention of the peptides by the reversed-phase column was dependent on their hydrophobicity, two solvent compositions were required for the retention of all peptides. Under these conditions, we detected the peptides by LC-MRM/MS using a column-switching method. Further, we succeeded in quantifying the peptides in the serum of pregnant women using stable isotope dilution. Conclusion Our new peptidomics method has great value for peptides, particularly those that have no specific antibody as a detection tool. Using this system, the serum peptides in patients with hypertensive disorders of pregnancy can be validated as diagnostic markers of hypertensive disorders of pregnancy. Further, this method can potentially be applied to the general quantification of other serum peptides.