siRNA directed against the APOE4 gene was selected for this study as the literature data indicates APOE4 as a factor in many disorders observed in Alzheimer’s disease, including disturbance of insulin signalling pathways in the brain, abnormal distribution of cholesterol and fatty acids, reduction of the integrity of the BBB and a decrease in glucose uptake by the brain21. The gene discussed is APOE; the disease is Alzheimer disease.