In vitro fabrication of a tissue engineered human cardiovascular patch for future use in cardiovascular surgery.
BACKGROUND
One approach to tissue engineering has been the development of in vitro conditions for the fabrication of functional cardiovascular structures intended for implantation. In this experiment, we developed a pulsatile flow system that provides biochemical and biomechanical signals in order to regulate autologous, human patch-tissue development in vitro.


METHODS
We constructed a biodegradable patch scaffold from porous poly-4-hydroxy-butyrate (P4HB; pore size 80 to 150 microm). The scaffold was seeded with pediatric aortic cells. The cell-seeded patch constructs were placed in a self-developed bioreactor for 7 days to observe potential tissue formation under dynamic cell culture conditions. As a control, cell-seeded scaffolds were not conditioned in the bioreactor system. After maturation in vitro, the analysis of the tissue engineered constructs included biochemical, biomechanical, morphologic, and immunohistochemical examination.


RESULTS
Macroscopically, all tissue engineered constructs were covered by cells. After conditioning in the bioreactor, the cells were mostly viable, had grown into the pores, and had formed tissue on the patch construct. Electron microscopy showed confluent smooth surfaces. Additionally, we demonstrated the capacity to generate collagen and elastin under in vitro pulsatile flow conditions in biochemical examination. Biomechanical testing showed mechanical properties of the tissue engineered human patch tissue without any statistical differences in strength or resistance to stretch between the static controls and the conditioned patches. Immunohistochemical examination stained positive for alpha smooth muscle actin, collagen type I, and fibronectin. There was minor tissue formation in the nonconditioned control samples.


CONCLUSIONS
Porous P4HB may be used to fabricate a biodegradable patch scaffold. Human vascular cells attached themselves to the polymeric scaffold, and extracellular matrix formation was induced under controlled biomechanical and biodynamic stimuli in a self-developed pulsatile bioreactor system.
Yang
Chao
C
Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany.
Sodian
Ralf
R
Fu
Ping
P
Lüders
Cora
C
Lemke
Thees
T
Du
Jing
J
Hübler
Michael
M
Weng
Yuguo
Y
Meyer
Rudolf
R
Hetzer
Roland
R
D020341:Absorbable Implants; D001011:Aorta / Q000166:cytology; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D019149:Bioreactors; D006348:Cardiac Surgical Procedures; D002455:Cell Division; D002478:Cells, Cultured / Q000166:cytology / Q000378:metabolism; D002648:Child; D003094:Collagen / Q000096:biosynthesis; D004549:Elastin / Q000096:biosynthesis; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology*; D005109:Extracellular Matrix / Q000378:metabolism; D005544:Forecasting; D006801:Humans; D020007:Implants, Experimental; D008422:Materials Testing; D011091:Polyesters; D011673:Pulsatile Flow; D012212:Rheology; D023822:Tissue Engineering / Q000379:methods*
D001672:Biocompatible Materials; D011091:Polyesters; C107955:poly(4-hydroxybutanoate); D003094:Collagen; D004549:Elastin