In vitro extracellular matrix deposition by vascular smooth muscle cells grown in fibroin scaffolds, and the regulation of TGF-β1

Abstract

The main risk of tissue-engineered implant materials is the stimulation of exogenous materials to the body. In order to reduce immune rejection and promote the growth of autologous cells, we attempted in vitro matrix formation by culturing human aorta smooth muscle cells (SMCs) in a silk fibroin (SF) porous scaffold, and investigated the synthesis and deposition of extracellular matrix (ECM) components in scaffolds, including collagen-I, collagen-III and elastin. We also investigated the regulatory effect of transforming growth factor β1 (TGF-β1). SMCs displayed higher survivability and proliferation after treatment with TGF-β1 than untreated controls at 1 week after inoculation. SMCs in the SF scaffolds exhibited efficient synthesis of ECM-related proteins. All three proteins were deposited in scaffolds, and this was promoted by treatment with TGF-β1. Incipient expression of collagen-III was lower than that of elastin and collagen-I, but it was increased significantly at 2 weeks. The phenotype of SMCs in SF scaffolds changed from a synthetic phenotype to a contraction phenotype after inoculation for 2 weeks. However, treatment with TGF-β1 slowed down this phenotypic transformation, and enhanced the ECM protein synthesis ability. This method could potentially be used for a wide range of polymers where specific architectures and microenvironments are required.