For example, ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) has been used in studies on traumatic brain injury (Blyth et al., 2011; Brophy et al., 2011) and has been repurposed as a possible biomarker for POD, for example, in Lopez et al., where higher postoperative levels of UCH-L1 was associated with increased POD risk (Lopez et al., 2020). Here, UCHL1 is linked to brain injury.