Kristen Garcia, Bioengineering Ph.D. Program, UC San Diego

Co-Mentors: Daniela Valdez-Jasso, Bioengineering

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by pulmonary vascular remodeling and is represented by the narrowing of blood vessels in the lungs. I am interested in gaining a deeper understanding of the remodeling process of the right ventricle (RV) from the cellular-level up to the organ-level in PAH, and to determine how estrogen or other sex-differences affects this process. PAH is four times more likely to affect females over males, specifically females between the ages of 30-60 years old. I am working with an animal model to look across the multiple scales of the heart. On the organ-level, I use cardiac magnetic resonance imaging (cMRI) and in vivo pressure-volume relationships to quantitatively analyze the systolic/diastolic function of the heart. Diffusion-tensor MRI imaging (DTI) is also used to get the geometry and fiber orientation of the organ as a whole. These two imaging techniques are used to create a biventricular mesh of the heart. Next, mechanical tests on the planar biaxial device are used to determine stress-strain measurements on the tissue level, which can help determine how the stiffness changes in relation to the progression of PAH. Using tissue engineering applications, the tissue is decellularized to look at the effect of the extracellular matrix on the stress-strain measurements, and mechanobiology of the cellular level is determined to conclude how cells change over disease stages. Combining the knowledge of all these experiments will allow for us to use and adapt a very useful three-dimensional model that can help predict how structural and functional changes in the RV lead to RV failure, and how this is affected by the sex of the animal. I am currently in the process of using cMRI and DTI data to determine the myofiber directions throughout the heart and looking into levels of estrogen and its relation to the hemodynamic data results. 

The video of this presentation can be found here.