Vascular tissue engineering - Biomaterials and Devices for the Circulatory System - page 306

Rittgers, 1997; Brewster et al. , 2008; Deutsch et al. , 2009; Laube et al. , 2000;
Magometschnigg et al. , 1992; Meinhart et al. , 2001; Rosenman et al. , 1985;
Seifalian et al. , 2002; Tiwari et al. , 2001, 2003a,b; Turner et al. , 2006; Vinard
et al. , 1999). Collagen, fi bronectin, plasma and fi brin, separately or com-
bined, have also been used to promote adhesion (Gosselin et al. , 1995, 1996;
Gray et al. , 1994; Greisler et al. , 1992; Meinhart et al. , 2001).
Despite the aforementioned techniques to improve the patency of syn-
thetic conduits showing encouraging results, none of them has been rou-
tinely employed by surgeons. The failure of synthetic grafts may be ascribed
to thrombosis in the early phase, incomplete graft healing in the intermedi-
ate phase and intimal hyperplasia in the late phase. Completely healed
synthetic grafts should resemble naturally occurring vessels with an entirely
confl uent luminal layer of ECs and fi brous tissue in-growth via the intersti-
tium and anastomoses (Kito and Matsuda, 1996). As this has not been
achieved satisfactorily to date, attention has turned to the alternatives,
namely wholly biological tissue engineered vascular conduits.

12.3 Tissue engineered arteries: historical and

modern perspectives

Tissue engineering requires a multidisciplinary approach, combining knowl-
edge and technology of cells, engineering materials and appropriate bio-
chemical factors to create artifi cial organs (Langer and Vacanti, 1993). The
engineering of functional and reliable tissue substitutes to combat disease
with fewer complications and minimal risk to the patient is gaining favour
in clinical practice. The tissue engineering fi eld is constantly and rapidly
evolving as there is a great deal still requiring investigation. Rigorous
research into the engineering and regeneration of various tissue types,
including liver parenchyma, cartilage and bone as well as functional con-
duits, is ongoing (Fausto et al. , 2006; Jukes et al. , 2010; Onyekwelu et al. ,
2009). The aim of these approaches is to engineer new tissue which may
replace a lost organ or regenerate structures damaged through disease or
trauma. The cells used in this process would be harvested from the patient
or from an appropriate donor.
With suitable bypass grafts being in short supply and surgeons reluctantly
employing synthetic conduits, alternative conduits are being sought. In
order to be suitable, tissue engineered blood vessels (TEBVs) would need
to mimic the characteristics of the natural occurring vasculature
(Tranquillo, 2002). Were a tissue engineered graft to be employed as a
bypass conduit, it would need to be easy to handle and suture into position.
The TEBV would also need to be immediately effective without any
leakage, degradation or rejection. Apart from being morphologically com-
parable to the native arteries, the ideal TEBVs, once implanted, would

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