Objective: To identify protein biomarkers in order to classify ischemic stroke subtypes using proteomic analysis and immunoenzymatic tools for clinical validation.
Methods and results: We performed a proteomic analysis in serum samples of 24 patients with ischemic stroke (12 atherothrombotic patients and 12 cardioembolic patients). In this study, based on two-dimensional electrophoresis and mass spectrometry we found four spots whose expression intensity was at least four times stronger in atherothrombotic patients than in cardioembolic patients. These spots were identified as haptoglobin related protein, serum amyloid A (two spots) and haptoglobin alpha chain. We validated the possible value of haptoglobin and serum amyloid A in a larger series of patients (n=262) with ischemic stroke using ELISA techniques. Haptoglobin levels >1040microg/mL identified atherothrombotic patients with 95% sensitivity and 88% specificity whereas serum amyloid A levels >160microg/mL identified atherothrombotic patients with 91% sensitivity and 83% specificity.
Conclusions: Haptoglobin and serum amyloid A are useful biomarkers for atherothrombotic ischemic stroke diagnosis confirmation.