Tissue-engineered vascular grafts demonstrate evidence of growth and development when implanted in a juvenile animal model.
BACKGROUND
The development of a living, autologous vascular graft with the ability to grow holds great promise for advancing the field of pediatric cardiothoracic surgery.


OBJECTIVE
To evaluate the growth potential of a tissue-engineered vascular graft (TEVG) in a juvenile animal model.


METHODS
Polyglycolic acid nonwoven mesh tubes (3-cm length, 1.3-cm id; Concordia Fibers) coated with a 10% copolymer solution of 50:50 L-lactide and epsilon-caprolactone were statically seeded with 1 x 10 cells/cm autologous bone marrow derived mononuclear cells. Eight TEVGs (7 seeded, 1 unseeded control) were implanted as inferior vena cava (IVC) interposition grafts in juvenile lambs. Subjects underwent bimonthly magnetic resonance angiography (Siemens 1.5 T) with vascular image analysis (www.BioimageSuite.org). One of 7-seeded grafts was explanted after 1 month and all others were explanted 6 months after implantation. Neotissue was characterized using qualitative histologic and immunohistochemical staining and quantitative biochemical analysis.


RESULTS
All grafts explanted at 6 months were patent and increased in volume as measured by difference in pixel summation in magnetic resonance angiography at 1 month and 6 months. The volume of seeded TEVGs at explant averaged 126.9% +/- 9.9% of their volume at 1 month. Magnetic resonance imaging demonstrated no evidence of aneurysmal dilation. TEVG resembled the native IVC histologically and had comparable collagen (157.9 +/- 26.4 microg/mg), elastin (186.9 +/- 16.7 microg/mg), and glycosaminoglycan (9.7 +/- 0.8 microg/mg) contents. Immunohistochemical staining and Western blot analysis showed that Ephrin-B4, a determinant of normal venous development, was acquired in the seeded grafts 6 months after implantation.


CONCLUSIONS
TEVGs demonstrate evidence of growth and venous development when implanted in the IVC of a juvenile lamb model.
Brennan
Matthew P
MP
Department of Surgery, Yale School of Medicine, New Haven, CT 06520, USA.
Dardik
Alan
A
Hibino
Narutoshi
N
Roh
Jason D
JD
Nelson
Gregory N
GN
Papademitris
Xenophon
X
Shinoka
Toshiharu
T
Breuer
Christopher K
CK
D000818:Animals; D001672:Biocompatible Materials; D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D001854:Bone Marrow Cells / Q000502:physiology*; D023421:Models, Animal; D009000:Monocytes / Q000502:physiology*; D011100:Polyglycolic Acid; D011474:Prosthesis Design; D012756:Sheep; D013526:Surgical Mesh; D023822:Tissue Engineering; D014682:Vena Cava, Inferior
D001672:Biocompatible Materials; D011100:Polyglycolic Acid
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