For instance, APOE’s genetic ablation in elderly mice caused a reduction in neuritic plaques and a decrease in the associated neuronal synaptic loss and glia activation, suggesting that APOE might be helpful against certain features of aging per se [28]; however, these neuroprotective effects have not been observed in the context of the AD-associated APP/PSEN1 mouse model, in which APOE may be neurotoxic. Here, APOE is linked to Alzheimer disease.