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Repopulation of gamma radiated aortic valve matrices

Pamela Somers (UGent) , Filip De Somer (UGent) , Bart Vandekerckhove (UGent) and Guido Van Nooten (UGent)
Author
Organization
Abstract
Objectives: Xenogenic extracellular heart valve matrices have been suggested as scaffolds for tissue engineering. However, these matrices need to be cross-linked in order to mitigate immune reaction. Moreover, cross-linked matrices should be repopulated with the appropriate cell type to create a viable and biocompatible valve with the ability to grow, repair and remodel. The aim of this study was to repopulate gamma-radiated matrices with human mesenchymal stem cells (hMSCs). Methods: Porcine matrices were prepared by a detergent-enzymatic treatment and were exposed to 1-10 Gy gamma-irradiation in 0.9% NaCl. Tensile strength and pore size of the matrices was evaluated. hMSCs were isolated from bone marrow and differentiated into myofibroblasts by the use of TGF-ß. The irradiated matrices were seeded with myofibroblasts and grown in vitro in a dynamic system (bioreactor). A natural cocktail of growth factors from autologous platelets was added to the culture medium. Analysis of the matrices included histology, immunohistology and transmission electron microscopy (TEM). Results: Gamma-radiation was fine-tuned in order to maintain a minimum pore size of 10 µm to allow cell in-growth (3-6 Gy). Tensile strength increased in irradiated matrices at the expense of elasticity. Immunohistochemical analysis showed active myofibroblasts positive for vimentin and desmin. Formation of stress fibres was confirmed by positive α-SMA staining. Microscopic evaluation of the cultivated matrices showed mesenchymal cell in-growth. Conclusions: Repopulating of gamma-radiated matrices was feasible using an autologous cocktail of growth factors. Cross-linked xenogenic matrices should retain a defined porosity in order to be repopulated with the appropriate cell type

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Chicago
Somers, Pamela, Filip De Somer, Bart Vandekerckhove, and Guido Van Nooten. 2009. “Repopulation of Gamma Radiated Aortic Valve Matrices.” In Society for Heart Valve Disease, 5th Biennial Meeting, Abstracts.
APA
Somers, P., De Somer, F., Vandekerckhove, B., & Van Nooten, G. (2009). Repopulation of gamma radiated aortic valve matrices. Society for Heart Valve Disease, 5th Biennial meeting, Abstracts. Presented at the 5th Biennial meeting of the Society for Heart Valve Disease.
Vancouver
1.
Somers P, De Somer F, Vandekerckhove B, Van Nooten G. Repopulation of gamma radiated aortic valve matrices. Society for Heart Valve Disease, 5th Biennial meeting, Abstracts. 2009.
MLA
Somers, Pamela, Filip De Somer, Bart Vandekerckhove, et al. “Repopulation of Gamma Radiated Aortic Valve Matrices.” Society for Heart Valve Disease, 5th Biennial Meeting, Abstracts. 2009. Print.
@inproceedings{2128988,
  abstract     = {Objectives: Xenogenic extracellular heart valve matrices have been suggested as scaffolds for tissue engineering. However, these matrices need to be cross-linked in order to mitigate immune reaction. Moreover, cross-linked matrices should be repopulated with the appropriate cell type to create a viable and biocompatible valve with the ability to grow, repair and remodel. The aim of this study was to repopulate gamma-radiated matrices with human mesenchymal stem cells (hMSCs). 
Methods: Porcine matrices were prepared by a detergent-enzymatic treatment and were exposed to 1-10 Gy gamma-irradiation in 0.9\% NaCl. Tensile strength and pore size of the matrices was evaluated. hMSCs were isolated from bone marrow and differentiated into myofibroblasts by the use of TGF-{\ss}. The irradiated matrices were seeded with myofibroblasts and grown in vitro in a dynamic system (bioreactor). A natural cocktail of growth factors from autologous platelets was added to the culture medium. Analysis of the matrices included histology, immunohistology and transmission electron microscopy (TEM).
Results: Gamma-radiation was fine-tuned in order to maintain a minimum pore size of 10 {\textmu}m to allow cell in-growth (3-6 Gy). Tensile strength increased in irradiated matrices at the expense of elasticity. Immunohistochemical analysis showed active myofibroblasts positive for vimentin and desmin. Formation of stress fibres was confirmed by positive \ensuremath{\alpha}-SMA staining. Microscopic evaluation of the cultivated matrices showed mesenchymal cell in-growth.
Conclusions: Repopulating of gamma-radiated matrices was feasible using an autologous cocktail of growth factors. Cross-linked xenogenic matrices should retain a defined porosity in order to be repopulated with the appropriate cell type},
  author       = {Somers, Pamela and De Somer, Filip and Vandekerckhove, Bart and Van Nooten, Guido},
  booktitle    = {Society for Heart Valve Disease, 5th Biennial meeting, Abstracts},
  language     = {eng},
  location     = {Berlin, Germany},
  title        = {Repopulation of gamma radiated aortic valve matrices},
  year         = {2009},
}