Furthermore, hypoxia, ischemia, and cellular stress can contribute to the elevation of BACE1 levels, and a deficit in energy leads to acidosis and oxidative stress in neurons, initiating a series of pathological events, including enzyme dysfunction and impaired protein synthesis resulting in the aggregation of both abnormal tau and Aβ proteins.38 Observational studies examining whether HF is a risk factor for AD yield conflicting results. Here, MAPT is linked to Alzheimer disease.