Regulation of Smooth Muscle Cells' Phenotypic Diversity in 3D by Means of ECM Components and Stiffness for Vascular Tissue Engineering: An In Vitro Evaluation of Cell Response

  • Sara B.H. Timraz

Student thesis: Master's Thesis

Abstract

Smooth muscle cells (SMC) exhibit phenotypic plasticity whereby the homeostatic contractile phenotype can dedifferentiate into the pathophysiologic synthetic phenotype. This is highly dependent on the signals they receive within their cellular environment. The disparity in physiological function denotes their distinct characteristics. This thesis studies the phenotypic plasticity of human SMC in the aim of providing useful knowledge to pose control over their phenotype in vitro. Experiments conducted in this thesis employed commercially available human vascular SMC due to the lack of availability of primary cells. The effects of conventional passaging on the phenotype of commercial SMC were first assessed, and their capacity to maintain their contractile phenotype in culture was evaluated. We showed that an early passage population of SMC adopted a fully differentiated contractile phenotype, while passages beyond P7 dedifferentiated into the synthetic phenotype. We subsequently demonstrated in vitro control of human SMC phenotype cultured within 3D gels that are fabricated of native extracellular matrix (ECM) components, collagen type I alone (Col I) or supplemented with either laminin (Col I+LN) or fibronectin (Col I+FN). Our results have shown that Col I+LN gels promoted and maintained the contractile phenotype, while FN-supplemented gels promoted the synthetic phenotype. We further evaluated the effect of matrix stiffness on the phenotype of SMC, presence of FN causes a shift towards the synthetic phenotype, while LN-supplemented matrices sustained a contractile phenotype regardless of matrix stiffness. 3D Col I matrices seem to promote the synthetic phenotype of human SMC with increasing stiffness of gels compared to Col I+FN or Col I+LN gels. Overall, the work presented in this thesis provides tools to modulate the phenotype of human SMC, which allows for tailoring the properties of engineered vascular tissues.
Date of AwardDec 2015
Original languageAmerican English
SupervisorJeremy Teo (Supervisor)

Keywords

  • Smooth muscle cells
  • phenotypic diversity
  • passage number
  • collagen
  • stiffness.

Cite this

'