CYBB and ischemia: Of note, gp91phox is the catalytic subunit of NADPH oxidase and BBB disruption is significantly reduced in gp91phox knockout mice compared to wild-type mice after stroke (Kahles et al., 2007) and reduction of gp91phox expression has shown protective effect against ischemia-induced brain injury and BBB damage (Liu et al., 2008, 2011).