Abstract 17179: Stress-Mediated Platelet Activation Contributes to Thrombosis: Findings From the American Heart Association Go Red for Women Strategically Focused Research Network

Background: Psychological stress is a risk factor for cardiovascular disease (CVD). Despite advancements in CV-prevention, CVD remains the global leading cause of disease burden, suggesting that additional factors contribute to sustained CV risk. The mechanisms by which stress contributes to increased CVD are largely unknown. However, in preclinical models increased sympathetic nervous system activity promotes systemic inflammation (e.g. monocyte activation, cytokine production), and may underlie increased CVD risk. We investigated perceived stress in women with MI and its association with platelet activity, and validated our findings in a murine model. Methods: Monocyte-platelet aggregates (MPA) and psychological stress, using the validated Perceived Stress Scale (PSS4), were measured in women post MI (n=96; median age 62.2 years) and in control women (n=31; 66.7 years). A mouse model of chronic variable stress was utilized to explore the impact of stress on platelet activity and risk of thrombosis-mediated death. Results: Perceived stress was higher in MI patients than matched women (p=0.009). Platelet activity, assessed by MPA, was significantly elevated in MI vs. controls (p=0.0025). MPA significantly correlated with PSS4 scores (R=0.412, p =0.009). In a female mouse model of chronic variable stress, circulating MPA was increased in stressed mice compared to controls (p<0.05), and platelet activation markers P-selectin and JON/A were increased on platelets from stressed mice relative to stress free mice (p<0.05). Using a platelet mediated thrombosis model, time to thrombosis and survival was reduced in stressed mice. Conclusion: Platelet activity was increased at the time of MI in women, and positively associated with stress. In a mouse model, we find that stress is a significant contributor to increased platelet reactivity, and promotes thrombosis-mediated death. Cross-talk between platelets and monocytes is a critical mechanism linking thrombosis and inflammation, thus stress-induced MPAs may represent an unexplored pathway linked to stress-mediated CVD-risk. Future studies will examine whether reducing stress reduces platelet hyperactivity and MI risk.