Animal models of vascular cognitive impairment and dementia

Vascular cognitive impairment and dementia (VCID) is the second most common cause of dementia behind Alzheimer’s disease (AD). In addition, VCID commonly occurs comorbid with AD, with conservative estimates of around 50% of sporadic AD cases also having some vascular comorbidity. The primary underlying pathologies of VCID are small vessel disease, characterized by microinfarcts, microhemorrhages, and white matter hyperintensities; large vessel disease characterized by poststroke dementia; and finally cerebral amyloid angiopathy. As has been the case for AD, animal models of VCID will not realistically be able to recapitulate the entire pathological process of VCID in the aging human brain. However, animal models offer a unique opportunity to study specific pathologies in isolation, understand the molecular mechanisms underlying these pathologic processes, and begin to identify therapeutic targets for VCID. We will discuss the limitations and strengths of these models and the important research findings that have advanced the field through the use of the models. Given the prevalence of VCID, both in isolation and comorbid with AD, there is a clear need for animal models to study specific pathologies. There has been an advance in development of these models, and the goal of this chapter is to provide discussion of these models, along with the strengths and weaknesses of each.