Extracellular Dynamics in Valvular and Vascular Pathophysiology
Monroe, Madeline Noel
Grande-Allen, K. Jane
Doctor of Philosophy
The extracellular matrix varies dramatically in composition and mechanics between tissues, thereby guiding differential physiological function. Within the cardiovascular system, even the slightest pathologically-induced changes in the extracellular matrix can inhibit proper tissue and organ function, leading to severe, life-threatening outcomes. The global objective of this thesis was to characterize the interplay of cells and extracellular matrix in physiological and pathological conditions in order to identify factors that encourage disease progression. In the first aim, I employed a three-dimensional, multilaminar, filter paper culture system to assess the effect of material substrate on valvular interstitial cell proclivity to calcification. This innovative culture system was previously established in the Grande-Allen lab for analyzing valvular interstitial cell migration and response to hypoxic environments. The tunability and high-throughput nature of the system lent itself to the implementation of complex culture environments. Therefore, I adapted this system with hydrogels that mimic aortic valve ultrastructure and varied the proportion of hydrogels within 3D stacks to assess whether specific extracellular components facilitate disease progression. The second aim explored differential behavior of male- and female-derived valvular interstitial cells and, moreover, the influence of androgens on cellular behavior within two-dimensional and three-dimensional culture systems. This was motivated by recent clinical work that demonstrated distinct pathological presentation of calcific aortic valve disease in male and female patients. Given that there is a distinct sex-linked difference in calcific aortic valve disease risk and development, I sought to determine if sex hormones were responsible for this trend. In the last aim, I shifted focus to investigating the effect of congenital diaphragmatic hernia on pulmonary vasculature extracellular matrix, and whether a novel mesenchymal stromal cell-derived extracellular vesicle treatment deterred this pathological remodeling. A myograph system, traditionally used in contractile vessel studies, was adapted to measure stress/strain behavior in main pulmonary arteries extracted from murine models. Histological analysis was performed to determine relative levels of fundamental extracellular matrix proteins and enzymes. Altogether, this dissertation calls attention to extracellular matrix factors within aortic valves and pulmonary arteries that potentially mediate pathological remodeling, thereby providing targets for the development of pharmacological or tissue-engineered therapies.
extracellular matrix; valve disease; pulmonary hypertension; congenital diaphragmatic hernia; biomaterials