ABSTRACT
Cardiovascular disease (CVD), the leading cause of death in the U.S., disproportionately impacts persons of
lower socioeconomic position (SEP) -- a disparity that has been attributed to heightened exposures to both traffic-
related air pollution (TRAP) and chronic social stressors. Many epidemiologic and toxicologic studies have shown
that exposures to chronic stress can vastly increase susceptibility to TRAP, though growing evidence now
suggests that TRAP may also strongly impact hypothalamic-pituitary-adrenal (HPA)-axis function and acute
stress response, complicating the directionality and interpretation of interactions. It is critical to disentangle these
two models, to develop more biologically-grounded epidemiologic model structures, and refine the design of
space-time exposure metrics for both stress and pollution. Ultimately, this work will help to better identify
susceptible populations, and identify effective interventions to improve health and reduce health disparities.
Doing so is challenging, however, as both stress and TRAP are complex exposures with diverse multi-systemic
impacts. Stress is shown to strongly impact immune, endocrine, and metabolic function, but effects are highly
time-sensitive, as acute and chronic stress manifest very differently. TRAP is a highly complex mix of chemicals,
each with very different physiologic impacts. In this ViCTER proposal, we establish an interdisciplinary team to
quantify and compare chronic and acute stress, TRAP, and their multiple interactions, in shaping cardiovascular
function. We are uniquely poised to map this unexplored terrain, as accomplished senior investigators in
atmospheric science and mechanical engineering (Wexler), cardiovascular regulation and autonomic function
(Chen), and exposure science and social-environmental epidemiology (Clougherty). To do so, we will use a
unique TRAP delivery system with real-time concentration and chemical composition measures, a well-validated
model for generating chronic and acute stress responses in rats, time-resolved measures of cardiovascular
function (telemetry), and biological profiling at multiple time points for chronic and acute stress markers (e.g.,
cortisol, CRP, cytokines), to quantify and compare directionality in the two conceptual models described above.
We hypothesize that: (1) TRAP composition (light- vs. heavy-duty vehicles) differently impact cardiovascular
function; (2) Chronic stress may heighten animals’ cardiovascular response to TRAP, over the course of study;
(3) TRAP may compromise animals’ cardiovascular resilience to stress challenge. This study will establish an
interdisciplinary team with complementary expertise to examine complexities in the interactions among stress
and pollution exposures – an issue profoundly relevant to health disparities in under-served and marginalized
communities, especially for CVD, the leading cause of death. The team will work together to integrate the results
of the three aims into hypotheses for subsequent R01 applications.