Data and methods Accepted project proposals Blood pressure changing the healthy brain

Author: Anil Tuladhar
Affiliation(s): Donders Center of Medical Neurosciences, Radboud university medical centre            
Research question(s): 
Are blood pressure levels in healthy, young individuals related to microstructural integrity of the brain?
Link: OSF Preregistration

Cerebral small vessel disease (SVD) is the major vascular cause of dementia and stroke, affecting approximately seventy million people worldwide.1-3 These diseases have an immense societal impact as they lead to a loss of independent life. Little is known about SVD pathophysiology, in part because the diseased small vessels cannot be visualized in vivo.4 Moreover, a major issue impeding our progress is that studies on SVD are mostly conducted among individuals > 60 years in whom disease mechanisms are expected to be present for decades already. To advance understanding of key mechanisms implicated in SVD, studies conducted in young/middle aged adults that are able to catch the first signs of SVD, when irreversible tissue damage has not occurred yet, are urgently needed. 
Although hypertension is recognized as an established risk factor for SVD, its role in the pathophysiology of SVD is poorly understood.3 Interestingly, hypertension during midlife is associated with a higher risk of developing cognitive impairment and dementia.5 It is suggested that during this period, elevated blood pressure causes slight alterations in the smallest vessels of the brain, eventually damaging the small vessels and surrounding brain tissue. However, it remains unknown if blood pressure levels are already associated with cerebral changes in healthy, young individuals. 
We therefore aim to assess early changes in microstructural integrity of the brain related to blood pressure by using Diffusion Tensor Imaging (DTI). A linear relation between blood pressure levels and microstructural integrity in the cerebral white matter and white matter hyperintensities in older individuals with SVD has been demonstrated, but it remains unknown if this association is also present in healthy individuals without evident cerebrovascular damage.6 This is relevant because no early, non-invasive markers for SVD currently exist, limiting both diagnosis and treatment to the late stages of the disease and its sequelae.