Blood biomarkers in ischemic stroke: Role of biomarkers in differentiation of clinical phenotype

Stroke is the major cause of death and disability worldwide and ischemic stroke contributes 80% among them. Although limited number of patients display hemorrhagic stroke (HS), the disability and death rate are higher in HS. Several studies have been reported on identification of suitable markers for diagnosis of stroke, but none of them holds true worldwide. These observations direct toward identification of population-specific biomarker of stroke. In this study, we screened various blood biomarkers in a large cohort of well-characterized Chinese stroke patients and healthy controls. A total of 308 stroke patients including 262 acute ischemic stroke (AIS) patients and 42 HS patients were enrolled in the study and blood samples were collected within 6-24 h of stroke onset. In addition, 46 stroke mimic subjects were included for comparison of blood markers with stroke patients. Furthermore, healthy controls (n = 200) and patient controls (n = 125) from similar ethnic group were enrolled in the study. Biomarkers (S100 calcium-binding protein B (S100B), C-reactive protein (CRP), interleukin 6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), matrix metallopeptidase 9 (MMP-9), P-selectin, intercellular adhesion molecule 1 (ICAM-1), tumor necrosis factor alpha (TNF-alpha), low-density lipoprotein (LDL) cholesterol, interleukin 10 (IL-10), nitric oxide (NO), and glial fibrillary acidic protein (GFAP)) were quantified by ELISA. Blood levels of S100B, CRP, IL-6, PAI-1, MMP-9, P-selectin, ICAM-1, and TNF-alpha were significantly higher in AIS and HS patients compared to healthy controls, patient controls, and stroke mimic patients. Receiver operating characteristic (ROC) curve analysis revealed CRP, IL-6, PAI-1, P-selectin, and TNF-alpha as possible biomarkers for AIS patients, and HS patients can be diagnosed based on S100B, IL-6, PAI-1, MMP-9, and TNF-alpha. Interestingly, significant area under ROC curves were observed for plasma S100B and CRP for differentiating AIS from HS. The results of this study validated certain blood parameters used for diagnosis of AIS or HS in Chinese patients. Furthermore, S100B and CRP are promising biomarkers for differentiation of AIS from HS.