Affinity proteomics discovers decreased levels of AMFR in plasma from Osteoporosis patients.

PURPOSE: Affinity proteomic approaches by antibody bead arrays enable multiplexed analysis of proteins in body fluids. In the presented study, we investigated blood plasma within osteoporosis to discovery differential protein profiles and to propose novel biomarkers candidates for subsequent studies. EXPERIMENTAL DESIGN: Starting with 4608 antibodies and plasma samples from 22 women for an untargeted screening, a set of 72 proteins were suggested for further analysis. Complementing these with targets from literature and other studies, a targeted bead array of 180 antibodies was built to profile for 92 proteins in plasma samples of 180 women from two independent population-based studies. RESULTS: Differential profiles between osteoporosis patients and matched controls were discovered for 12 proteins in at least one of the two study sets. Among these targets, the levels of autocrine motility factor receptor (AMFR) were concordantly lower in plasma of female osteoporosis patients. Subsequently, verification of anti-AMFR antibody selectivity was conducted using high-density peptide and protein arrays, and Western blotting. CONCLUSIONS AND CLINICAL RELEVANCE: Further validation in additional study sets will be needed to determine the clinical value of the observed decrease in AMFR plasma levels in osteoporosis patients, but AMFR may aid our understanding of disease mechanisms and could support existing tools for diagnosis and monitoring of patient mobility within osteoporosis.