Screening of plasma biomarkers in patients with unstable angina pectoris with proteomics analysis / 解放军医学杂志

ABSTRACT

Objective To analyze and compare the differentially expressed plasma proteins between patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP), and search for the biomarkers that maybe used for early diagnosis of UAP. Methods Sixty plasma samples were collected respectively from normal controls group (N group), SAP group and UAP group during Jun. 2014 to Apr. 2015 from the Third Affiliated Hospital of Southern Medical University. Ten samples (100μl) of each group were selected randomly to pool into 3 groups severally. After removing high-abundance proteins from plasma, two-dimensional difference gel electrophoresis (DIGE) was used to isolate the total proteins, and then the protein spots with more than 2-fold changes between UAP and SAP were picked up after the differential software analysis. Afterward, the varied proteins were identified by matrix assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) mass spectrometry (MS). Finally, 40 plasma samples were collected respectively from N, SAP and UAP group, and the UAP specific differential proteins were selected to be verified by ELISA. Results A total of 10 varied protein spots with more than 2-fold changes in UAP and SAP were found including 9 up-regulated proteins and 1 down-regulated one. MS identification indicated that the up-regulated proteins included fibrinogen gamma chain (FGG), complement C4-B (C4B), immunoglobulin (Ig) kappa chain C region (IGKC) and hemoglobin subunit alpha (HBA1), whereas the down-regulated one was haptoglobin (HP). After comparing the varied proteins with that in N group, 2 specifically UAP-related proteins, IGKC and HP, were detected totally. IGKC was selected to validate by ELISA, and the corresponding results showed that IGKC was increased specifically in UAP plasma (P<0.05) when compared with N and SAP group, which was consistent with DIGE. Conclusion IGKC and HP have been detected as specifically related proteins to UAP, and IGKC might serve as a potential specific biomarker for screening and early diagnosis of UAP.