Similar observations were made for noise exposure-induced endothelial dysfunction that was completely prevented in gp91phox knockout mice upon 1 or 2 days of noise exposure, whereas upon 4 days of noise exposure, only partial protection by gp91phox deficiency was observed, most likely because other ROS sources such as mitochondria take over after prolonged noise exposure (Fig. 4) (Kroller-Schon et al, 2018). Here, CYBB is linked to endothelial dysfunction.