Panminerva medica
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The prevalence, morphology, and pathogenesis of vascular dementia (VaD), recently termed vascular cognitive impairment (VCI), and of mixed dementia (Alzheimer disease associated with vascular encephalopathy) are a matter of discussion and clinical diagnostic criteria for these disorders slow low sensitivity and variable specificity. In Western memory clinic-based series, VaD/VCI is suggested in 8-10% of cognitively impaired elderly subjects. Its prevalence in autopsy series ranges from 0.03% to 58% with reasonable values of 4-10%. ⋯ Minor cerebrovascular lesions, except for severe amyloid angiopathy, appear not essential for cognitive decline in full-blown AD, while both mild AD-type pathology and small vessel disease may interact synergistically in ''unmasking'' or promoting dementia. AD pathology is significantly less severe in the presence of cerebrovascular lesions. Further studies are needed to validate diagnostic criteria for VaD/VCI and to clarify the impact of vascular lesions on cognitive impairment as a basis for more precise clinical diagnosis, early prevention and management.
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Review
Cerebrovascular disease and the pathophysiology of Alzheimer's disease. Implications for therapy.
Dementia is a disease of the elderly, and although there are many causes of dementia, Alzheimer's disease (AD) and vascular dementia (VaD) account for the majority of cases world- wide. Many patients with dementia have radiological and neuropathological features of AD and VaD, with the classical neurofibrillary tangles and senile amyloid-beta (Abeta) plaques of AD together with the cerebral infarcts of VaD. In this review we examine the close relationship between AD and VaD and suggest that the age changes in cerebral blood vessels that are the basis of cerebrovascular disease and VaD may also be responsible for the failure of elimination of Abeta from the brain in AD. ⋯ In aged individuals, insoluble Abeta amyloid fibrils are deposited in the ISF drainage pathways resulting in cerebral amyloid angiopathy (CAA). We review the evidence that age changes in cerebral arteries and cerebrovascular disease inhibit the perivascular drainage of ISF and Abeta along the walls of cerebral arteries resulting in the accumulation of insoluble and soluble Abeta in the brain in AD. Therapies for AD are reviewed, especially those involving immunotherapy for the removal of insoluble Abeta from the cerebral cortex and the facilitation of drainage of ISF and soluble Abeta from the brain.