CD44 and Cognitive impairment: Based on previous finding about roles of YKL-40 in repair and remodelling (Zhao T et al. 2020), it was hypothesised that CD44 and YKL-40 are responsible for neuroprotection during cognitive impairment (Kognole AA and Payne CM 2017; Moreno-Rodriguez M et al. 2020; Toole BP 2009).