PROJECT SUMMARY
The Systolic Blood Pressure Intervention Trial (SPRINT) demonstrated that intensive blood pressure (BP)
targets significantly reduced risks of cardiovascular disease (CVD) and mortality, leading to new guidelines
recommending a lower BP target of <130/80 mm Hg. However, intensive BP targets may increase the risk of
adverse events from antihypertensive therapy. With widespread adoption of the new BP guidelines, there is
an urgent need to evaluate whether there are subgroups of patients who may have an unfavorable balance of
benefits and harms from intensive BP lowering. We propose an innovative approach to risk stratification that
integrates traditional risk factors with novel information gleaned from mitochondrial DNA (mtDNA).
Mitochondria are intracellular organelles that are essential for energy metabolism and stress adaptation. In
animal models, mitochondrial dysfunction plays a fundamental role in aging, CVD, and neurodegenerative
diseases. Because mitochondrial metabolism is vital to adapt positively to bioenergetic stressors such as BP
lowering, measures of mitochondrial health may help to predict beneficial and adverse outcomes among
adults undergoing intensive treatment for hypertension. Recent observational studies have linked novel
mtDNA measures with several age-related outcomes, including risks of CVD, hypertension, death, dementia,
and reduced functional status. However, the optimal methods for integrating data across the mitochondrial
genome have not been established, nor have prior studies investigated the utility of mtDNA measures for
identification of subgroups who may derive greatest benefits or harms from intensive BP targets.
This proposal will leverage next-gen sequencing technology and machine learning analytics to develop and
validate mtDNA risk scores that predict CVD risk, mortality risk, and longitudinal changes in cognitive and
physical function in older adults. Our first Aim will implement a biologically-informed neural network among
participants of the Health, Aging, and Body Composition Study (Health ABC; N=3,075) and the Lifestyle
Interventions and Independence for Elders Study (LIFE; N=1,755) to develop two mtDNA risk scores for
prediction of CVD and cognitive and physical function outcomes, while accounting for the competing risk of
death. Our second and third Aims will validate these mtDNA risk scores in two landmark trials that evaluated
the impact of intensive vs standard BP targets on cardiovascular outcomes: SPRINT (N=9,361) and Action to
Control Cardiovascular Risk in Diabetes (ACCORD; N=2,488). We will then examine whether mitochondrial
risk, assessed by these mtDNA scores, modifies the efficacy or safety of the BP interventions. This work will:
1) develop innovative methods for analysis of mitochondrial genomic data; 2) provide novel hypotheses
regarding pathways linking mitochondrial health, CVD risk and functional status; and 3) explore the potential
of mtDNA measures for personalized health interventions in older adults.