Recently, I was doing a literature review related to smooth muscle cells (SMCs) and tissue-engineered blood vessels (TEBV). In the case of TEBV fabrication, most researchers were using bioreactors to provide mechanical stimulation to SMCs seeded on the scaffold to improve the mechanical performance of TEBV. It was reported that mechanical stimulation can promote the ECM synthesis of SMCs [10.3727/096368909X471161][10.1016/j.biomaterials.2010.09.019]. However, based on other research related to SMCs, mechanical stimulation could lead to the transformation of the phenotype of SMCs, from synthetic type to contractile type [10.1161/JAHA.123.031121]. If so, the contractile SMCs will not "enhance" the ECM deposition then how mechanical stimulation can help to improve the mechanical characteristic of TEBV? I think these two ideas are contradictory and I hope some experts and experienced researchers in tissue engineering can give me some hints.