Tissue Engineering and Regenerative Medicine

, Volume 13, Issue 5, pp 507–515

Bioreactor conditioning of valve scaffolds seeded internally with adult stem cells

  • Allison Kennamer
  • Leslie Sierad
  • Richard Pascal
  • Nicholas Rierson
  • Christopher Albers
  • Marius Harpa
  • Ovidiu Cotoi
  • Lucian Harceaga
  • Peter Olah
  • Preda Terezia
  • Agneta Simionescu
  • Dan Simionescu
Original Article Tissue Engineering

DOI: 10.1007/s13770-016-9114-1

Cite this article as:
Kennamer, A., Sierad, L., Pascal, R. et al. Tissue Eng Regen Med (2016) 13: 507. doi:10.1007/s13770-016-9114-1

Abstract

The goal of this study was to test the hypothesis that stem cells, as a response to valve-specific extracellular matrix “niches” and mechanical stimuli, would differentiate into valvular interstitial cells (VICs). Porcine aortic root scaffolds were prepared by decellularization. After verifying that roots exhibited adequate hemodynamics in vitro, we seeded human adipose-derived stem cells (hADSCs) within the interstitium of the cusps and subjected the valves to in vitro pulsatile bioreactor testing in pulmonary pressures and flow conditions. As controls we incubated cell-seeded valves in a rotator device which allowed fluid to flow through the valves ensuring gas and nutrient exchange without subjecting the cusps to significant stress. After 24 days of conditioning, valves were analyzed for cell phenotype using immunohistochemistry for vimentin, alpha-smooth muscle cell actin (SMA) and prolyl-hydroxylase (PHA). Fresh native valves were used as immunohistochemistry controls. Analysis of bioreactor-conditioned valves showed that almost all seeded cells had died and large islands of cell debris were found within each cusp. Remnants of cells were positive for vimentin. Cell seeded controls, which were only rotated slowly to ensure gas and nutrient exchange, maintained about 50% of cells alive; these cells were positive for vimentin and negative for alpha-SMA and PHA, similar to native VICs. These results highlight for the first time the extreme vulnerability of hADSCs to valve-specific mechanical forces and also suggest that careful, progressive mechanical adaptation to valve-specific forces might encourage stem cell differentiation towards the VIC phenotype.

Key Words

Scaffolds Heart valves Stem cells Bioreactor 

Copyright information

© The Korean Tissue Engineering and Regenerative Medicine Society and Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Allison Kennamer
    • 1
  • Leslie Sierad
    • 1
  • Richard Pascal
    • 1
  • Nicholas Rierson
    • 1
  • Christopher Albers
    • 1
  • Marius Harpa
    • 2
  • Ovidiu Cotoi
    • 2
  • Lucian Harceaga
    • 2
  • Peter Olah
    • 2
  • Preda Terezia
    • 2
  • Agneta Simionescu
    • 3
  • Dan Simionescu
    • 1
    • 2
  1. 1.Biocompatibility and Tissue Regeneration Laboratories, Department of BioengineeringClemson University, 304 Rhodes AnnexClemsonUSA
  2. 2.Tissue Engineering and Regenerative Medicine Laboratory, Department of AnatomyUniversity of Medicine and PharmacyTargu MuresRomania
  3. 3.Cardiovascular Tissue Engineering and Regenerative Medicine LaboratoryDepartment of Bioengineering, Clemson UniversityClemsonUSA

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