Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Department

Biomedical Engineering

First Advisor's Name

Sharan Ramaswamy

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Lidia Kos

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Wei-Chiang Lin

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Nikolaos Tsoukias

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Vinu Unnikrishnan

Fifth Advisor's Committee Title

Committee Member

Keywords

Tissue Engineering, Stem Cell, Heart Valve

Date of Defense

3-20-2015

Abstract

Heart valve disease occurs in adults as well as in pediatric population due to age-related changes, rheumatic fever, infection or congenital condition. Current treatment options are limited to mechanical heart valve (MHV) or bio-prosthetic heart valve (BHV) replacements. Lifelong anti-coagulant medication in case of MHV and calcification, durability in case of BHV are major setbacks for both treatments. Lack of somatic growth of these implants require multiple surgical interventions in case of pediatric patients. Advent of stem cell research and regenerative therapy propose an alternative and potential tissue engineered heart valves (TEHV) treatment approach to treat this life threatening condition. TEHV has the potential to promote tissue growth by replacing and regenerating a functional native valve. Hemodynamics play a crucial role in heart valve tissue formation and sustained performance. The focus of this study was to understand the role of physiological shear stress and flexure effects on de novo HV tissue formation as well as resulting gene and protein expression. A bioreactor system was used to generate physiological shear stress and cyclic flexure. Human bone marrow mesenchymal stem cell derived tissue constructs were exposed to native valve-like physiological condition. Responses of these tissue constructs to the valve-relevant stress states along with gene and protein expression were investigated after 22 days of tissue culture. We conclude that the combination of steady flow and cyclic flexure helps support engineered tissue formation by the co-existence of both OSS and appreciable shear stress magnitudes, and potentially augment valvular gene and protein expression when both parameters are in the physiological range.

Identifier

FI15050204

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