Tai Chi Practice and Sleep-Active Glymphatic Function - PROJECT SUMMARY/ABSTRACT
Amyloid plaque deposition, a key pathological hallmark of Alzheimer’s disease (AD), begins 1-2 decades
before manifestation of clinical symptoms of dementia. Among cognitively intact individuals and in AD’s most
prevalent sporadic form, the production of amyloid-β (Aβ) does not change, while clearance of Aβ is slowed,
indicating that the failure of Aβ clearance may underlie the development of AD pathology and that interventions
that improve its clearance may provide an opportunity for primary prevention of AD. Over the past 10 years,
our group has helped to define the ‘glymphatic system’, a brain-wide network of perivascular pathways along
which cerebrospinal fluid (CSF) surrounding the brain exchanges with brain interstitial fluid, supporting the
clearance of interstitial wastes, including Aβ and tau. Impairment of glymphatic clearance is observed in the
aging brain and in mouse models of AD. Thus, improving glymphatic clearance of brain interstitial proteins may
be one approach to preventing the development of AD. Glymphatic function is regulated by sleep-wake
behavior, with faster clearance occurring during sleep. Tai Chi is a Chinese martial art focusing on mindful
body movement, posture, and breathing as an avenue to achieve a state of internal balance, calm, and clarity.
In clinical studies, practice of Tai Chi is associated with improved sleep quality, cognition, mood,
cardiovascular and respiratory function, and balance/physical activity. However, the physiological processes
underlying the cognitive and affective effects of Tai Chi remain undefined. We hypothesize that Tai Chi practice
improves glymphatic function. To test this hypothesis, we will enroll 75 middle-aged (50-70 years) participants
with different levels of Tai Chi practice experience: Tai Chi proficients (10+ year of practice, n=25), Tai Chi
beginners (12 months practice, n=25) and Tai Chi naïve participants (n=25). We will 1) examine the
association between Tai Chi practice and glymphatic function using multi-modal magnetic resonance imaging
(MRI) using contrast-enhanced MRI, T1/FLAIR assessment of MRI-visible perivascular spaces, intravoxel
incoherent motion, and fast BOLD-fMRI; 2) examine relationships between Tai Chi practice and sleep,
including sleep fragmentation, efficiency, and duration, assessed by self-reported questionnaires and objective
measurements of sleep duration, fragmentation and efficiency using a bed pressure mat. We will examine the
relationship between sleep measures and MRI-assessed glymphatic function. The ultimate goal of this study is
to elucidate mechanisms of Tai Chi practice in prevention of AD and related dementias. This pilot study will
determine whether long-term Tai Chi practice is associated with physiological changes in glymphatic function
and sleep. If we find cross-sectional association among Tai Chi practice, glymphatic function, and sleep, in the
future we will investigate whether these changes are associated with duration of Tai Chi practice and whether
these changes are associated with changes in AD biomarkers in a longitudinal study or in a prospective
randomized clinical trial.
