Construction of functional soft tissues from premodulated smooth muscle cells using a bioreactor system.

Artificial smooth muscle tissues should be constructed with well-differentiated and aligned smooth muscle cells (SMCs) for proper functioning. In a previous study, we produced cell/scaffold hybrids composed of consistently aligned SMCs in a contractile state using cyclic mechanical strain. In this study, the preconditioned hybrids were organized as functional smooth muscle constructs, which had a high cellular density, using a bioreactor system. We determined that the alignment and contractile phenotype of the initially generated SMCs would be retained after a 7-day culture period in a bioreactor. Mechanical properties of the smooth muscle constructs were measured and compared with those of native smooth muscle tissues and acellular scaffolds. The constructs had a denser cell concentration than the preconditioned hybrids, although they were not fully filled with cells. The premodulated cell alignment and contractile phenotype were retained after culture in a bioreactor. The 7-day-cultured constructs had similar allowed stress levels to native tissues while their stiffness was much lower, suggesting that they had malleable and durable characteristics. These results suggest that functional smooth muscle tissues with mechanical stability can be produced using premodulated SMCs and a bioreactor system.