MAPT and Alzheimer disease: Additionally, platelet A2A – an adenosine receptor, monoamine oxidase-B (MAO-B) – a mitochondrial membrane enzyme that catalyzes oxidative deamination and plays a role in neuroactive and vasoactive amine metabolism, high molecular weight / low molecular weight tau (HMW/LMW tau), nitric oxide (NO), and Peroxynitrite (ONOO-) were all shown to be upregulated in AD [18–21].