In Alzheimer's disease (AD), irreversible neurological damage takes place years before the onset of clinical symptoms. Therefore, it is recognized that the development of AD dementia treatment and prevention strategies relies on the early detection of presymptomatic pathology. Previous studies demonstrate that mitochondrial dysfunction plays a key role in the pathophysiology of AD and precedes the formation of plaques and tangles that are hallmarks of this disease. The premise of this study is based on the unique sensitivity of the brain to systemic bioenergetic decline due to its exceptionally high metabolic demand. We hypothesize that bioenergetic capacity is related to early AD pathology and that bioenergetic decline is associated with the long term progression and severity of this disease. Recent work by our group and others demonstrate that blood- based bioenergetic profiling, utilizing cellular respirometry, provides a reliable measure of systemic mitochondrial function. The proposed study will determine whether blood cell bioenergetics is related to AD risk, pathology, cognitive performance, and changes in these parameters over time. Our long term goal is to develop a minimally invasive screening tool that can be used in a clinic/community setting to identify candidates for more intensive diagnostic testing, such as CSF biomarker analysis and brain imaging. This project will be completed in an efficient and cost-effective manner by leveraging resources provided by the NIA-funded Wake Forest Alzheimer' Disease Center Clinical Core (ADCCC). Participants in the ADCCC represent a spectrum of AD risk and disease progression and are being extensively characterized for AD pathologies at baseline and 3 year follow ups. Our preliminary data from ADCCC participants indicate that bioenergetic capacity, measured in blood cells, is lower in participants with mild cognitive impairment. Moreover, our data suggest that bioenergetic deficits are already apparent in cognitively normal participants at high risk for AD.
The aims of the proposed study are: 1) To determine bioenergetic profiles most strongly associated with AD risk and reporters of AD pathology (cognitive performance, CSF A?42/tau, hippocampal volume, brain amyloid, and cerebral glucose metabolism); 2) To determine the changes in bioenergetic profiles related to the 3 year progression of cognitive decline and reporters of AD pathology; and, 3) To determine the relationships of mitochondrial content and inflammation with bioenergetic capacity, and reporters of AD pathology at baseline and at follow-up. A central goal of the proposed study is to determine the specific bioenergetic parameters that are most closely associated with AD risk and pathology. Therefore, in addition to convention analytical approaches, we will employ state of the art Machine Learning analyses to identify individual parameters or multivariate signatures that are most closely associated with AD risk and pathology. Completion of this project can impact the detection of presymptomatic AD, provide insights into mechanisms underlying bioenergetic decline associated with AD, and broadly advance translational bioenergetics research.
It is widely recognized that the implementation of successful Alzheimer's disease prevention and treatment strategies rely on the identification of patients at risk for developing the disease. The proposed project will examine blood based bioenergetic profiling as a minimally invasive strategy for determining Alzheimer's disease risk and presymptomatic pathology. The completion of our study aims will advance the development of an affordable screening tool that can be utilized in a clinical/community setting to identify individuals who are candidates for comprehensive diagnostic testing.