The roles of apolipoprotein E ε4 on neuropathology and neuroinflammation in patients with Alzheimer's disease.

Aims: To explore the roles of apolipoprotein E (APOE) ε4 on the neuropathology and neuroinflammation in Alzheimer's disease (AD) patients.

Methods: AD patients were divided into the APOE ε4 carrier and the APOE ε4 non-carrier groups according to APOE genotype. Demographic information, cognitive function, the levels of neuropathological proteins and neuroinflammatory factors in cerebrospinal fluid (CSF) were compared between the two groups, and their correlations were subsequently analyzed.

Results: β amyloid protein (Aβ) level from the APOE ε4 carrier group was significantly lower than that from the non-carrier group (p = 0.023), which was associated with worse cognitive function. The nitric oxide (NO) level was significantly elevated in the APOE ε4 carrier group compared to the non-carrier group (p = 0.016), which was significantly and positively correlated with the Trail Making Test (TMT)-A-time (r = 0.21, p = 0.026) and TMT-B-time (r = 0.38, p < 0.01).

Conclusion: APOE ε4 is associated with poorer cognition, particularly the early symptoms of memory, language, and attention. APOE ε4 is associated with lower Aβ level, and the more numbers of APOE ε4 are carried, the lower level of Aβ is measured. APOE ε4 is associated with elevated NO level, which is linked to the impaired attention and executive function.