Vascular pathology in Parkinson’s disease and dementia with Lewy bodies

This study aims to determine the frequency and severity of cerebrovascular changes in different neuropathological subgroups of Parkinson’s disease (PD) and Dementia with Lewy bodies (DLB) together with their impact on clinical features of the patients. The frequency and severity of different vascular pathologies - including cerebral amyloid angiopathy (CAA), parenchymal arteriosclerosis/lipohyalinosis (AS/LH), and atherosclerosis in the circle of Willis (AS-CW) - as well as ischemic lesions, and haemorrhages were analyzed in autopsy verified PD (n = 103) and clinically diagnosed DLB patients (n = 16). Additionally, 80 matched controls were included in the study. Diagnosis was made using the CERAD protocol (for Alzheimer-related lesions) and consensus guidelines for the diagnosis of DLB. Clinical data were compiled retrospectively. According to their Lewy body (LB) scores, all PD and DLB patients fell into three major subgroups (brainstem predominant, limbic/transitional, and neocortical types). The frequencies of moderate and severe of AS/LH, AS-CW, as well as ischemic lesions were found significantly less often in patients with a higher LB score, in which such advanced pathologies were most predominant in patients with brainstem-predominant type. In marked contrast, CAA was positively correlated with LB score, in which CAA was most frequent in patients with the neocortical type. We conclude that PD or DLB patients with advanced LB pathology are less likely to show a history of stroke. Possible reasons for these findings are discussed in terms of (a) effect of drug treatment, (b) vascular autoregulation of the brain, and (c) frequency of diabetes mellitus, hypertension and autonomic dysregulation.