Because the most altered CNS n-6 fatty acid metabolite on LA diet in EFAD mice was docosapentaenoic acid (DPAn-6) which can serve as a substrate for anti-inflammatory resolving lipid mediators, we tested the impact of daily direct gavage administration of DPAn-6 on neuroinflammation in late stages of a severe AD pathology model E4FAD (APOE4-TR+/+/5xFAD+/−) mice for three weeks, which carries human APOE4 targeted replacement (APOE4-TR+/+). This evidence concerns the gene APOE and Alzheimer disease.