Vascular smooth muscle cells as a valvular interstitial cell surrogate in heart valve tissue engineering.
BACKGROUND
Vascular smooth muscle cells (VSMCs) are a potential autologous cell source for aortic valve tissue engineering, but have a phenotype that differs from that of valvular interstitial cells in vivo. We hypothesized that combining basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), or platelet-derived growth factor (PDGF) with transforming growth factor beta-1 (TGF-beta1) would achieve a valvular interstitial cell-like phenotype of VSMCs.


METHODS
VSMC phenotype was assessed by immunofluorescence, proliferation was measured by the tetrazolium reduction (MTT) assay, and extracellular matrix gene expression was determined by real-time polymerase chain reaction.


RESULTS
Combinations of growth factors that included PDGF showed the greatest increases in proliferation. Immunofluorescence for alpha-smooth muscle actin demonstrated an inverse correlation between proliferation and a myofibroblast-like phenotype, while combinations of TGF-beta1+ EGF+bFGF (TEF) and TGF-beta1+EGF+PDGF (TEP) induced the greatest change of alpha-smooth muscle actin expression compared to untreated controls. Finally, TEP treatment showed an increase in versican, fibronectin, and type I collagen mRNA expression, while decreasing matrix metalloproteinase 1 expression.


CONCLUSIONS
Combination of TGF-beta1 with EGF and PDGF induces VSMC proliferation and expression of extracellular matrix constituents found in the aortic valve. In vitro preconditioning of VSMCs provides a potentially viable surrogate cell source for developing a valve graft.
Appleton
Andrew J E
AJ
Department of Anatomy and Cell Biology, The Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada.
Appleton
C Thomas G
CT
Boughner
Derek R
DR
Rogers
Kem A
KA
D000199:Actins / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D018929:Cell Culture Techniques; D003094:Collagen / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects / Q000235:genetics; D005455:Fluorescent Antibody Technique; D005782:Gels; D005786:Gene Expression Regulation / Q000187:drug effects; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000166:cytology*; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000379:methods*
D000199:Actins; D003094:Collagen; D005782:Gels; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; C498862:Acta2 protein, rat