Serum biomarkers of vascular cognitive impairment evaluated by bead-based proteomic technology

To investigate the biomarkers of vascular cognitive impairment (VCI), we analyzed 30 VCI patients and 30 healthy controls using proteome technology. Peptides in sera were purified using magnetic beads, and analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and ClinProTool software. Twenty-four peptides were significantly differently expressed between VCI patients and controls. There were seven peptides selected for our diagnostic model. The sensitivity of the model measured by internal and external validation was 95% and 80% respectively, while the specificity was 100% for both. A peptide peak at 4963 m/z was chosen for identification by nano-liquid chromatography-electrospray ionization-tandem mass spectrometry (nano-LC-ESI-MS/MS). The amino acid sequence was consistent with the fragment of the trace-amine associated receptor 6 (TAAR6) in the human international protein index database. In conclusion, the specific fragment of TAAR6 may be important for clinical biomarkers in the diagnosis of VCI. The high specificity and sensitivity of the model may provide an appropriate method for screening VCI patients.