MAPT and Alzheimer disease: This is unlikely to reflect solely the increase in Aβ level evoked by ischaemia/hypoxia discussed above, because tau phosphorylation occurs in hypertensive rats (which are ischaemic and hypoxic) even without Aβ pathology [147] and is evoked by unilateral carotid artery occlusion in AD mice without a rise in Aβ1–42 level [145].