Cerebral Microvascular Amyloid β Protein Deposition Induces Vascular Degeneration and Neuroinflammation in Transgenic Mice Expressing Human Vasculotropic Mutant Amyloid β Precursor Protein

Cerebral vascular amyloid β-protein (Aβ) deposition, also known as cerebral amyloid angiopathy, is a common pathological feature of Alzheimer's disease. Additionally, several familial forms of cerebral amyloid angiopathy exist including the Dutch (E22Q) and Iowa (D23N) mutations of Aβ. Increasing evidence has associated cerebral microvascular amyloid deposition with neuroinflammation and dementia in these disorders. We recently established a transgenic mouse model (Tg-SwDI) that expresses human vasculotropic Dutch/Iowa mutant amyloid β-protein precursor in brain. Tg-SwDI mice were shown to develop early-onset deposition of Aβ exhibiting high association with cerebral microvessels. Here we present quantitative temporal analysis showing robust and progressive accumulation of cerebral microvascular fibrillar Aβ accompanied by decreased cerebral vascular densities, the presence of apoptotic cerebral vascular cells, and cerebral vascular cell loss in Tg-SwDI mice. Abundant neuroinflammatory reactive astrocytes and activated microglia strongly associated with the cerebral microvascular fibrillar Aβ deposits. In addition, Tg-SwDI mouse brain exhibited elevated levels of the inflammatory cytokines interleukin-1β and −6. Together, these studies identify the Tg-SwDI mouse as a unique model to investigate selective accumulation of cerebral microvascular amyloid and the associated neuroinflammation.