The above evidence suggests that the progressive structural damage of mLVs in APP/PS1 mice (manifested by reduced LYVE-1 expression) may have been the pathological basis for the progressive decline in their drainage function, and that meningeal lymphatic dysfunction may have aggravated AD-related pathological processes by hindering the clearance of metabolic waste products (such as Aβ) in the brain. This evidence concerns the gene APP and Alzheimer disease.