Measurement of brain and plasma fibrinogen levels

Brain homogenates were made by sonicating one cerebral hemisphere (without cerebellum) in radioimmunoprecipitation assay buffer (Sigma #R0278) containing protease and phosphatase inhibitors (Pierce #88669). Lysates were centrifuged twice at 13,300 rpm for 15 min. Pellets were discarded and supernatants were kept for analysis. For plasma sample collection, blood samples were collected in heparin-sodium (1:10) via cardiac puncture and centrifuged at 6000 rpm for 5 min. Plasma was collected and spun again at 13,300 rpm for 5 min to remove any residual blood cells. Brain homogenates (1:30 dilution) and plasma samples (1:20,000 dilution) were analyzed for fibrinogen levels by ELISA (Genway; cat #GWBBB0BA2) following the manufacturer’s protocol.