Phenotype modulation in vascular tissue engineering using biochemical and mechanical stimulation.
Biochemical stimulation was applied in combination with cyclic mechanical strain to engineered vascular constructs made of isolated smooth muscle cells in a three-dimensional (3D) collagen type 1 matrix. Platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF-beta) were added exogenously to the medium used to culture the constructs. Mechanical stimulation was applied using a bioreactor system that imparted a 10% circumferential strain at a frequency of 1 Hz. The parameters studied were gel compaction, cell proliferation, and expression of the contractile protein smooth muscle alpha-actin (SMA). Mechanical stimulation caused a characteristic increase in gel compaction and cell proliferation, relative to statically cultured controls. Stimulation with PDGF increased cell proliferation and decreased SMA expression in 3D gels, but inhibited the effects of mechanical stimulation and produced a more open matrix structure. TGF-beta strongly inhibited cell proliferation and increased SMA expression, especially in the presence of mechanical strain, and resulted in a dense matrix. These results show that cell phenotype can be modulated in engineered blood vessels by applying selected combinations of biochemical and mechanical stimuli, and suggest that such control over cell function can be used to tailor the properties of engineered tissues.
Stegemann
Jan P
JP
Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA.
Nerem
Robert M
RM
D000199:Actins / Q000096:biosynthesis; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D019149:Bioreactors; D001807:Blood Vessel Prosthesis; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D024042:Collagen Type I / Q000737:chemistry / Q000502:physiology; D046508:Culture Techniques / Q000379:methods; D003720:Densitometry / Q000379:methods; D005782:Gels; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D010641:Phenotype; D010812:Physical Stimulation / Q000379:methods; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013268:Stimulation, Chemical; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D000199:Actins; D024042:Collagen Type I; D005782:Gels; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta