EDN1 and early-onset autosomal dominant Alzheimer disease: Here we show that PDGFRβ and EDN1 (and to some extent fibrinogen) levels are related to amyloid-β42 in Braak tangle stage III–IV and V–VI disease but not BS0–II, perhaps reflecting a threshold effect of classical Alzheimer’s disease pathological processes on the regulation of these vasoactive molecules.