Date of Award

8-2022

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Bioengineering

Committee Chair/Advisor

Agneta Simionescu

Committee Member

Dan Simionescu

Committee Member

Martine LaBerge

Abstract

The most complex heart valve is the mitral valve (MV). Many pathologies can affect the MV, including stenosis, regurgitation, prolapse, and mitral annulus calcification (MAC). MAC is chronic degeneration of the annulus, which is the fibrous, saddle-shaped “ring” that can contract and relax with the myocardium. The prevalence of MAC is around 15% but increases in patients with other cardiovascular diseases and risk factors. It is also thought to increase in patients with type 2 diabetes, but MAC has not been properly characterized within this population because of confounding factors such as cardiac disease and kidney disease. The goal of this project is to reveal the interactions between the mitral valve annular cells, valvular endothelial cells (VECs) and valvular interstitial cells (VICs), that lead to calcification. To study the effects of diabetic conditions on MAC and the MV, we investigated 2D and 3D cell cultures of VECs and VICs. We had two aims for this project: 1) investigate diabetes-induced alterations of mitral valve cells in 2D cell culture under static and dynamic conditions and 2) explore diabetes-induced modifications of mitral valve cells and extracellular components in 3D cell culture under dynamic conditions. The Flexcell compression system was used to study 2D dynamic cell culture, and a tissue engineered MV and MV bioreactor were used for 3D cell culture. The tissue engineered MV was made by seeding a decellularized porcine MV with porcine VECs and VICs. This valve was placed in the bioreactor with high glucose cell culture media, and it ran for seven days under diabetic conditions. Samples from the 2D cell cultures as iii well as the bioreactor were analyzed using immunofluorescence and western blotting. Proteins of interest included osteocalcin, a calcium-binding protein typically found in bone, α-smooth muscle actin, and glycated proteins containing carboxymethyl lysine. Results show that osteocalcin and carboxymethyl lysine expression increased in the diabetic model. This suggests that there may be a relationship between diabetes and MAC.

Available for download on Thursday, August 31, 2023

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