Thrombin induces secretion of amyloid precursor protein (APP) in endothelial cells in vitro (Ciallella et al., 1999) and may be involved in altered processing of APP into fragments that are found in amyloid plaques of AD brains (Igarashi et al., 1992; Chong et al., 1994; Ciallella et al., 1999). This evidence concerns the gene APP and Alzheimer disease.