Cognitive deficits in human ApoE4 knock-in mice: A systematic review and meta-analysis.
Level 5 - mechanism / opinion, no new human data
Preclinical animal research (systematic review and meta-analysis of rodent studies)
PubMed 38972485 · doi:10.1016/j.bbr.2024.115123
What was done
Researchers conducted a systematic review, meta-analyses, and meta-regression analyses across 61 published studies evaluating cognitive performance differences between human targeted-replacement ApoE4 and ApoE3 knock-in mice. Eligible studies evaluated at least one of four behavioral paradigms: the Morris Water Maze (MWM), novel object location (NL), novel object recognition (NO), or the Fear Conditioning (FC) test.
What was found
Compared to ApoE3 mice, ApoE4 mice demonstrated statistically significantly worse performance across several behavioral assays: MWM across multiple outcomes (Hedges' g ranging from 0.17 to 0.60), novel object recognition exploration (g = 0.33) and index (g = 0.44), and contextual fear conditioning (g = 0.49). Meta-regression revealed that performance differences between ApoE4 and ApoE3 mice were not systematically associated with sex or age.
Why it matters
This synthesis establishes baseline effect sizes for cognitive phenotypes in ApoE4 knock-in models without secondary Alzheimer's pathology, confirming mild intrinsic cognitive vulnerability that does not depend on age or sex.
Limits
The findings derive exclusively from preclinical rodent models and cannot be directly translated to human clinical outcomes. The abstract does not report pooled effect sizes for novel object location (NL), quantitative measures of between-study heterogeneity, or assessments of publication bias.
Cited by
- supports Humanized APOE4 mice exhibit reduced cerebral blood flow, increased blood-brain barrier leakage, and cognitive deficits in novel object recognition and location tasks compared to APOE3 mice.