Loss of dopamine neurons leads to many of the clinical features of Parkinson disease (PD) but does not account for the progression of critical axial motor features, including postural instabiliy and gait impairments that tend to be refractory to dopaminergic medications and play a large role in disability. We recently published cross-sectional findings linking cardiovascular risk factors with the rate of axial motor feature accrual in PD. This effect was partially explained by the severity of chronic microvascular pathology, measured as white matter hyperintensities (WMHs) seen on brain MRI. If microvascular brain pathologies are responsible for causing medication-refractory motor impairments in PD, the early identification and treatment of high-risk subjects using targeted cardiovascular risk factor reduction interventions has the potential to serve as a disease modifying strategy impacting the health care of many Veterans with PD, in whom cardiovascular comorbidities are seen more commonly. In order to design effective clinical trials aimed at lowering complications due to comorbid microvascular brain pathology, however, a more detailed understanding of the mechanistic link between cardiovascular risk factors and clinically meaningful outcomes is essential. I propose to study the impact of cardiovascular risk factors and microvascular brain pathology on axial motor features in a 2-year longitudinal cohort study of individuals with early Parkinson disease.
Aim 1 will test a longitudinal hypothesis drawn from our preliminary cross-sectional data: PD patients with greater baseline cardiovascular risk factor burden develop more rapid progression of axial motor features and greater WMH burden at 2 year follow-up.
Aim 2 will use arterial spin labeling (ASL) MRI to identify regional impairments in cerebral blood flow (CBF) and cerebrovascular reserve capacity (CvRC) in early PD subjects with cardiovascular risk factors before the progression to irreversible microvascular injury takes place. These studies will not only serve as a novel natural history study of microvascular changes in PD, they will also facilitate the identification of PD subjects at highest risk for comorbid microvascular changes, permitting the design of a future intervention trial focused on targeted, early cardiovascular risk factor reduction. The goal of thi potential disease modifying strategy would be to slow the rate of medically refractory axial motor feature accrual in Veterans with PD. If successful, this approach would have implications for other neurodegenerative conditions as well. The practical experience of this project along with the formal training plan in neuroimaging, epidemiology, and clinical trials methodology included in this CDA-2 proposal will facilitate my career growth into a MERIT-funded clinician-investigator who aims to usher novel therapeutic strategies into the realm of PD clinical trials.

Public Health Relevance

Dopamine-replacement medications are the most widely used treatments for Parkinson disease (PD) but do not significantly help important walking and balance difficulties described collectively as 'axial' motor features. Cardiovascular risk factors may contribute towards axial motor features by worsening brain vascular changes. We propose a longitudinal study of Veterans with PD to better understand the links between cardiovascular risk factors and microvascular brain injury with the long-term aim of identifying a target for a disease-modifying treatment strategy in PD.

Agency
National Institute of Health (NIH)
Institute
Veterans Affairs (VA)
Type
Veterans Administration (IK2)
Project #
5IK2CX001186-03
Application #
9476211
Study Section
Epidemiology (EPID)
Project Start
2016-04-01
Project End
2020-03-31
Budget Start
2018-04-01
Budget End
2019-03-31
Support Year
3
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Veterans Health Administration
Department
Type
DUNS #
096318480
City
Ann Arbor
State
MI
Country
United States
Zip Code
48105
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Kotagal, Vikas; Spino, Cathie; Bohnen, Nicolaas I et al. (2018) Serotonin, ?-amyloid, and cognition in Parkinson disease. Ann Neurol 83:994-1002
Kotagal, Vikas; Albin, Roger L; Müller, Martijn L T M et al. (2018) Cardiovascular Risk Factor Burden in Veterans and Non-Veterans with Parkinson Disease. J Parkinsons Dis 8:153-160
Bohnen, Nicolaas I; Haugen, Jacob; Ridder, Andrew et al. (2017) Color discrimination errors associate with axial motor impairments in Parkinson's disease. Mov Disord Clin Pract 4:864-869
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Kotagal, Vikas; Lineback, Christina; Bohnen, Nicolaas I et al. (2016) Orthostatic hypotension predicts motor decline in early Parkinson disease. Parkinsonism Relat Disord 32:127-129