APOE and early-onset autosomal dominant Alzheimer disease: The e4 isoform has been implicated in atherosclerosis, ischemic cerebrovascular disease, impaired cognitive function, and late‐onset Alzheimer's disease.36 Several studies have shown that patients with APOE e4 have a poorer outcome after TBI.37 In this study, we explored the mechanism of wild‐type murine ApoE on white matter remodeling after TBI; however, whether different ApoE isoform (e2, e3 or e4) has a similar function should be examined in future studies.