Open AccessAntibody-Free Mass Spectrometry Identification of Vascular Integrity Markers in Major Trauma
Author(s) -
Holly E. Hinson,
Jon Jacobs,
Shan K. McWeeney,
Ann Wachana,
Tujin Shi,
Kendall not provided Martin,
Karin Rodland
Publication year - 2021
Publication title -
neurotrauma reports
Language(s) - English
Resource type - Journals
ISSN - 2689-288X
DOI - 10.1089/neur.2021.0007
Subject(s) - mass spectrometry , identification (biology) , antibody , chemistry , medicine , chromatography , biology , immunology , botany
Antibody mediated strategies for protein biomarker detection are common, but may limit discovery. We hypothesized that the use of antibody-free proteomics is feasible for detecting protein biomarkers in plasma of patients sustaining major trauma. A subset of subjects with major trauma from a prospective observational trial were analyzed. Patients were assigned to one of four groups based on their presenting Abbreviated Injury Severity Score (AIS). Sensitive, antibody-free selective reaction monitoring (SRM) mass spectrometry (MS), with spiked-in isotopically labeled synthetic peptides, was used for targeted protein quantification of a panel of 10 prospective targets. An overall tiered sensitivity analytical approach was used for peptide detection and quantification based upon plasma immunoaffinity depletion and PRISM fractionation. Forty-four patients were included in the analysis, of which 82% were men with a mean age of 50 (±19) years. Half had isolated head injury ( n = 22), with the remaining patients experiencing multiple injuries or polytrauma ( n = 14), isolated body injury ( n = 2), or minor injury ( n = 6). Peptides from 3 proteins (vascular adhesion molecule 1 [VCAM1], intercellular adhesion molecule 1 [ICAM1], and matrix metalloproteinase 9 [MMP9]) were detected and quantified in non-depleted processed plasma. Peptides from 2 proteins (angiopoietin 2 [Ang2] and plasminogen activator inhibitor-1 [PAI1]) were detected and quantification in depleted plasma, whereas the remaining 5 of the 10 prospective targets were undetected. VCAM1 ( p = 0.02) and MMP9 ( p = 0.03) were significantly upregulated in in the major trauma groups (1-3) versus mild injury group (4), whereas the others were not. There were no differences in protein expression between patients with traumatic brain injury (TBI; groups 1 and 2) versus those without TBI (groups 3 and 4). We detected non-specific upregulation of proteins reflecting blood-brain barrier breakdown in severely injured patients, indicating label-free MS techniques are feasible and may be informative.