Date of Award
12-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Bioengineering
Committee Chair/Advisor
Dr. Agneta Simionescu
Committee Member
Dr. Dan Simionescu
Committee Member
Dr. Brian Booth
Abstract
Mitral annular calcification (MAC) is a chronic, progressive, and degenerative condition that impairs mitral valve function and increases the risk of cardiovascular disease. The mitral annulus is a saddle-shaped, fibrous structure that is primarily composed of collagen and elastin. The annulus also contains interspersed lipids that are involved in cellular metabolism, as well as inflammatory and osteogenic signaling. These lipids increase the annulus’ susceptibility to calcification, under conditions that increase mechanical stress (hypertension) and promote atherosclerosis (diabetes mellitus). These conditions intensify calcification by promoting the activation of valvular interstitial cells (VICs), increasing fibrosis, and inducing osteogenic differentiation. Although it is established that diabetes is strongly associated with MAC, the mechanisms driving VIC-mediated calcification are poorly understood, and physiologically relevant experimental models to study these processes are limited.
This study addresses two objectives: (1) to investigate the therapeutic potential of N-acetyl-L-cysteine (NAC), an antioxidant and glutathione precursor, in reducing oxidative stress-induced VIC activation and calcification under diabetic conditions, and (2) to develop a tissue-engineered platform that could serve as a future model for studying mitral valve pathologies. A 2D cell-culture study was conducted to assess VIC activation and osteogenic differentiation under diabetic-like stress conditions with and without NAC, providing insight into the effects of oxidative stress and antioxidant treatment on valvular cell behavior. To create a physiologically relevant environment, hydrogels were developed from decellularized mitral valves, providing a native-like extracellular matrix (ECM) for VIC seeding; this approach could serve as a proof-of-concept for a tissue-engineered platform. Finally, a 3D dynamic culture system was developed by incorporating cell-seeded hydrogels into decellularized mitral valves and applying rotational culture to test the integration and retention of the hydrogel and cells within the annular tissue. This approach combines a mechanistic investigation of VIC activation in 2D with a 3D dynamic culture system, a hydrogel-based tissue-engineered model.
Overall, our results highlight the potential of NAC to limit oxidative stress-induced VIC activation and establish a foundation for a physiologically relevant tissue-engineered system that could be used to study MAC and other mitral valve pathologies in future research.
Recommended Citation
Keenan, Raleigh J., "Mitral Annular Calcification in Diabetes: Valvular Interstitial Cells, Antioxidant Therapy, and Tissue Engineering Approaches" (2025). All Theses. 4620.
https://open.clemson.edu/all_theses/4620