(264c) Quantifying the Impact of Acute Estrogen Exposure on Platelet Central Carbon Metabolism

Platelets are small (~2 micron), disc-shaped, anuclear blood cells involved in clotting. Chemical or mechanical stimuli such as a broken blood vessel triggers platelet activation, which allows platelets to increase their surface area, attach to other blood cells, and catalyze the formation of an insoluble clot¹. While they are essential for wound repair and to stop excess bleeding, platelets are also implicated in venous thromboembolism (VTE)^2-5. VTE can block blood flow and potentially cause a life-threatening pulmonary embolism. Pre-menopausal women have a lower incidence of VTE as compared to men and post-menopausal women⁶. However, people taking exogenous estrogen (such as for birth control or hormone replacement therapy) are at an estimated 4-fold increased risk of VTE; a risk that is highest during the first three months of treatment⁷. Despite the fact that estrogen containing medications have been available since the 1960’s, there is an incomplete understanding of how exogenous estrogen imparts this increased clotting risk. Platelets are of are interest because they contain estrogen receptors and are the primary cells involved in clotting⁸. It has been established that platelet activation and metabolism are tightly linked^9-17. Previous studies of platelet metabolism have utilized indirect measurements, such as oxygen consumption and extracellular acidification, as a semi-quantitative way to measure relative activities of respiration and glycolysis, respectively^{11, 18}. However, this method is subject to forms of error including buffering capacity of the media and acidification from CO₂ produced by respiration. We have previously used isotope assisted metabolic flux analysis (¹³C-MFA) to study platelet metabolism, but while detailed, this is low throughput¹⁴. In this study, we quantify the impact of acute estrogen exposure on resting and activated platelet metabolism by directly measuring major inputs and outputs of metabolism, as well as estrogen’s effect on markers of reversible and irreversible platelet activation. This allows us to quantify metabolic changes in a way that is higher throughput than ¹³C-MFA but more precise than Seahorse.

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(18) Lepropre, S.; Kautbally, S.; Octave, M.; Ginion, A.; Onselaer, M.-B.; Steinberg, G. R.; Kemp, B. E.; Hego, A.; Wra, O.; Brouns, S.; et al. AMPK-ACC signaling modulates platelet phospholipids and potentiates thrombus formation. Blood 2018, 132.

Not sure if poopooing on seahorse like this is necessary in an abstract