title: Bioengineered three-layered robust and elastic artery using hemodynamically-equivalent pulsatile bioreactor.
abstract: BACKGROUND
  There is an essential demand for tissue engineered autologous small-diameter vascular graft, which can function in arterial high pressure and flow circulation. We investigated the potential to engineer a three-layered robust and elastic artery using a novel hemodynamically-equivalent pulsatile bioreactor.
  
  
  RESULTS
  Endothelial cells (ECs), smooth muscle cells (SMCs), and fibroblasts were harvested from bovine aorta. A polyglycolic acid (PGA) sheet and a polycaprolactone sheet seeded with SMCs, and a PGA sheet seeded with fibroblast, were wrapped in turn on a 6-mm diameter silicone tube and incubated in culture medium for 30 days. The supporting tube was removed, and the lumen was seeded with ECs and incubated for another 2 days. The pulsatile bioreactor culture, under regulated gradual increase in flow and pressure from 0.2 (0.5/0) L/min and 20 (40/15) mm Hg to 0.6 (1.4/0.2) L/min and 100 (120/80) mm Hg, was performed for an additional 2 weeks (n=10). The engineered vessels acquired distinctly similar appearance and elasticity as native arteries. Scanning electron microscopic examination and Von Willebrand factor staining demonstrated the presence of ECs spread over the lumen. Elastica Van Gieson and Masson Tricrome Stain revealed ample production of elastin and collagen in the engineered grafts. Alpha-SMA and calponin staining showed the presence of SMCs. Tensile tests demonstrated that engineered vessels acquired equivalent ultimate strength and similar elastic characteristics as native arteries (Ultimate Strength of Native: 882+/-133 kPa, Engineered: 827+/-155 kPa, each n=8).
  
  
  CONCLUSIONS
  A robust and elastic small-diameter artery was engineered from three types of vascular cells using the physiological pulsatile bioreactor.
authors.affiliation: Laboratory for Tissue Engineering and Regenerative Medicine, Brigham and Women's Hospital, Harvard Medical School. 75 Francis Street, Thorn 1327, Boston, MA 02115, USA.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Iwasaki
authors.forename: Koji
authors.initials: K
authors.lastname: Kojima
authors.forename: Shohta
authors.initials: S
authors.lastname: Kodama
authors.forename: Ana C
authors.initials: AC
authors.lastname: Paz
authors.forename: Melody
authors.initials: M
authors.lastname: Chambers
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Umezu
authors.forename: Charles A
authors.initials: CA
authors.lastname: Vacanti
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001011:Aorta / Q000166:cytology; D001158:Arteries; D021522:Bioartificial Organs; D019149:Bioreactors; D002417:Cattle; D002478:Cells, Cultured; D004548:Elasticity; D004730:Endothelium, Vascular / Q000166:cytology; D004867:Equipment Design; D005347:Fibroblasts; D006439:Hemodynamics; D007150:Immunohistochemistry; D008855:Microscopy, Electron, Scanning; D032389:Myocytes, Smooth Muscle; D011108:Polymers; D011673:Pulsatile Flow; D013194:Staining and Labeling; D013314:Stress, Mechanical; D013718:Tensile Strength; D023822:Tissue Engineering
chemical_list: D011108:Polymers