Apolipoprotein E (APOE) secretion: Certain cells release APOE to supply lipid particles and vitamins to neurons, as well as to cleanse neurons by eliminating potentially hazardous "lipid waste." Reduced lipid metabolism: This reduced metabolism has been linked to neurodegenerative illnesses such as AD, impacting cell communication and other physiological functions within the brain [16]. This evidence concerns the gene APOE and Alzheimer disease.