Development of a seeded scaffold in the great omentum: feasibility of an in vivo bioreactor for bladder tissue engineering.
OBJECTIVE
Tissue engineering is very promising in bladder reconstruction. However, one of the main problems is to limit the development of ischaemic fibrosis during tissue maturation. We describe a model using the omentum as an in vivo bioreactor for a previously seeded scaffold.


METHODS
Bladder biopsies were taken from five female pigs, from which both urothelial and smooth muscle cells cultures were made. These cultured cells were used to seed a sphere-shaped small intestinal submucosa (SIS) matrix, which was transferred into the omentum after 3 wk of cell growth. The grafts were harvested 3 wk later and histologic, immunohistochemical, and functional studies were performed.


RESULTS
We obtained a highly vascularized tissue-engineered construct that contracted in response to acetylcholine stimulation. The wall thickness was 4mm, on average. Histologic and immunostaining analysis of the construct confirmed the presence of a multilayer urothelium on the luminal aspect and deeper fascicles organised tissue composed of differentiated smooth muscle cells and mature fibroblasts without evidence of inflammation or necrosis. Large- and small-diameter vessels were clearly identified histologically in the tissue obtained.


CONCLUSIONS
The omentum permitted in vivo maturation of seeded scaffolds with the development of a dense vascularisation that is anticipated to prevent fibrosis and loss of contractility. This in vivo maturation into the omentum could be the first step before in situ implantation of the construct.
Baumert
Hervé
H
Department of Urology, Paris Saint Joseph Hospital Trust, Paris, France. baumertherve@yahoo.fr
Simon
Pascal
P
Hekmati
Mehrak
M
Fromont
Gaëlle
G
Levy
Maryline
M
Balaton
André
A
Molinié
Vincent
V
Malavaud
Bernard
B
D000818:Animals; D019149:Bioreactors / Q000662:veterinary*; D017690:Cell Transplantation / Q000379:methods; D002478:Cells, Cultured; D005240:Feasibility Studies; D005260:Female; D007150:Immunohistochemistry; D009130:Muscle, Smooth / Q000166:cytology / Q000637:transplantation; D009852:Omentum; D013552:Swine; D023822:Tissue Engineering / Q000295:instrumentation*; D054457:Tissue Scaffolds / Q000662:veterinary*; D001743:Urinary Bladder / Q000166:cytology* / Q000502:physiology / Q000601:surgery; D019459:Urothelium / Q000166:cytology / Q000637:transplantation