Serum Glial Fibrillary Acidic Protein: Potential to Determine Stroke-Type, Time-Line and Tissue-Impact in Acute Stroke

ABSTRACT Background Interest is emerging regarding the role of blood biomarkers in acute stroke. The aim of this pilot study was to determine the feasibility of biomarker acquisition in suspected acute stroke, using modern ultrasensitive immunoassay techniques, and explore their potential usefulness for stroke diagnosis and management. Methods In 62 patients with suspected acute stroke, blood samples were prospectively obtained upon arrival and prior to neuroimaging. Serum levels (pg/mL) of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) were analyzed according to time of symptom onset, neuroimaging, and final diagnosis. Results Acute ischemic stroke (AIS) was diagnosed in 35 patients, 10 with large-vessel occlusion (LVO). The remaining were diagnosed with intracerebral hemorrhage (ICH) (n = 12), transient ischemic attack (n=4), and stroke mimics (n=11). Median(IQR) GFAP levels were significantly higher in ICH (2,877.8 [1,002.1-10,402.5] pg/mL) compared to others diagnoses. In AIS, GFAP levels appear to increase over time from symptom onset, and were higher in patients with more extensive ischemic changes on baseline CT (ASPECTS ≤ 7) than those without, particularly in LVO stroke. NfL values were similar across groups. Conclusions In acute stroke, serum GFAP shows potential as an adjunct tool for the distinction between ICH and AIS. Specific to AIS, GFAP may also offer insight into time from onset, and extent of ischemic tissue injury on neuroimaging, particularly in LVO stroke. These preliminary findings merit further study.