Acquired cerebral amyloid angiopathy: An emerging concept.

Cerebral amyloid angiopathy (CAA) is commonly found in older people and in patients with Alzheimer's disease (AD) accompanying cerebrovascular disorders and dementia. Early-onset CAA cases generally have been found only in rare genetic forms of CAA. Interestingly, however, CAA-related hemorrhages have been recently reported in younger people who had histories of neurosurgery with or without evidence of cadaveric dura mater grafts in childhood. It has been established in experimental settings that amyloid β-protein (Aβ) pathology can be transmitted inter-individually with Aβ seeds. Incidental Aβ pathology, predominantly Aβ-CAA, has been recognized in recipients of cadaveric dura mater grafts or cadaveric human growth hormone. These findings suggest that transmission of Aβ seeds through dura mater grafts and other contaminated materials could lead to development of CAA. In addition, neurosurgery or brain injury may contribute to cerebrovascular Aβ deposition through the disturbance of vascular Aβ drainage pathways. Thus, a novel concept, "acquired CAA," has emerged.