Adam J. Doyle

As blood transitions from steady laminar flow (S-flow) in healthy arteries to disturbed flow (D-flow) in aneurysmal arteries, platelets are subjected to external forces. Biomechanical platelet activation is incompletely understood and is a potential mechanism behind antiplatelet medication resistance. Although it has been demonstrated that antiplatelet drugs suppress the growth of abdominal aortic aneurysms (AAA) in patients, we found that a certain degree of platelet reactivity persisted in spite of aspirin therapy, urging us to consider additional antiplatelet therapeutic targets. Transcriptomic profiling of platelets from patients with AAA revealed upregulation of a signal transduction pathway common to olfactory receptors, and this was explored as a mediator of AAA progression. Healthy platelets subjected to D-flow ex vivo, platelets from patients with AAA, and platelets in murine models of AAA demonstrated increased membrane olfactory receptor 2L13 (OR2L13) expression. A drug screen identified a molecule activating platelet OR2L13, which limited both biochemical and biomechanical platelet activation as well as AAA growth. This observation was further supported by selective deletion of the OR2L13 ortholog in a murine model of AAA that accelerated aortic aneurysm growth and rupture. These studies revealed that olfactory receptors regulate platelet activation in AAA and aneurysmal progression through platelet-derived mediators of aortic remodeling.

May-Thurner syndrome (MTS) is a rare cause of deep vein thrombosis (DVT). This diagnosis is seldomly included in the differential diagnosis. The disease is defined as extraluminal iliac vein compression by the arterial system against bony structures in the iliocaval area. This occurs more commonly on the left side due to the unfortunate position of the proximal left iliac vein that runs between the right common iliac artery and spine. MTS is commonly presented in younger female patients with left unilateral proximal DVT. However, MTS is rarely reported in elderly patients. We present a case of a 69-year-old man with a diagnosis of MTS and further management with a venous stent.