Plasma Glycoproteomic Study of Therapeutic Hypothermia Reveals Novel Markers Predicting Neurologic Outcome Post-cardiac Arrest

Therapeutic hypothermia (TH) is a neuroprotective treatment post-cardiac arrest but is grossly underutilized. After TH induction, traditional biomarkers and parameters can no long predict clinical outcome due to a lack of understanding of hypothermic response. Innovative approaches to better understand the clinical effect of TH will help to prognosticate outcome and expand beneficial population. Protein glycosylation is an important extracellular post-translational modification, regulating various extracellular signaling pathways. Here, we used glycoproteomics to investigate the association of plasma glycoproteins with the prognosis of TH-treated cardiac arrest patients. Using lectin affinity chromatography and mass spectrometry, we identified 640 glycoproteins in the plasma of cardiac arrest patients undergoing TH treatment, of which 23 were up-regulated and 14 were down-regulated in good outcome patients as compared with poor outcome ones. Notably, two glycoproteins with antioxidant activity, ceruloplasmin (CP) and haptoglobin (HP), were found to be associated with favorable neurologic outcome. This was further supported by ELISA assay in a large patients cohort, in which glycosylated CP and HP enriched by concanavilin A (ConA) and wheat germ agglutinin (WGA) lectins were significantly increased in patients developing good outcome (ConA-CP: p = 0.033; ConA-HP: p = 0.04; WGA-HP: p = 0.021). Furthermore, ROC analysis demonstrated the predictive potential of ConA-CP, ConA-HP, and WGA-HP (ConA-CP: AUC = 0.732, p = 0.031; ConA-HP: AUC = 0.746, p = 0.022; WGA-HP: AUC = 0.714, p = 0.046) and combination of them improved the predictive power (AUC = 0.830, p = 0.002). Our results suggested that glycosylated CP and HP as well as other glycoproteins may play critical roles in neuroprotection and serve as sensitive prognostic markers for TH treatments.