Porous Three-Dimensional Silk Fibroin Scaffolds for Tracheal Epithelial Regeneration in Vitro and in Vivo

Abstract

The regeneration of functional epithelial lining is critical for artificial grafts to repair tracheal defects. Although silk fibroin (SF) scaffolds have been widely studied for biomedical application (e.g., artificial skin), its potential for tracheal substitute and epithelial regeneration is still unknown. In this study, we fabricated porous three-dimensional (3D) silk fibroin scaffolds and cocultured them with primary human tracheobronchial epithelial cells (HBECs) for 21 days in vitro. Examined by scanning electronic microscopy (SEM) and calcein-AM staining with inverted phase contrast microscopy, the SF scaffolds showed excellent properties of promoting cell growth and proliferation for at least 21 days with good viability. In vivo, the porous 3D SF scaffolds (n = 18) were applied to repair a rabbit anterior tracheal defect. In the control group (n = 18), rabbit autologous pedicled trachea wall without epithelium, an ideal tracheal substitute, was implanted in situ. Observing by endoscopy and computed tomography (CT) scan, the repaired airway segment showed no wall collapse, granuloma formation, or stenosis during an 8-week interval in both groups. SEM and histological examination confirmed the airway epithelial growth on the surface of porous SF scaffolds. Both the epithelium repair speed and the epithelial cell differentiation degree in the SF scaffold group were comparable to those in the control group. Neither severe inflammation nor excessive fibrosis occurred in both groups. In summary, the porous 3D SF scaffold is a promising biomaterial for tracheal repair by successfully supporting tracheal wall contour and promoting tracheal epithelial regeneration.

A Personalized Multifunctional 3D Printed Shape Memory‐Displaying, Drug Releasing Tracheal Stent

“…As reported in very recent studies, [ 50,51 ] engineering a tracheal stent that displays micrometric porosity is an additional, desired attribute. This feature is especially important in the context of tracheal Tissue Engineering, where the stent performs also as a scaffold for autologous tissue regeneration.…”

Influence of the Mechanical Environment on the Regeneration of Osteochondral Defects

“…GelMA has also been used in combination with hyaluronic acid (HA), which forms the backbone of aggrecan and therefore plays a critical role in maintaining the viscoelastic and mechanical properties of cartilage (Hemmati-Sadeghi et al, 2018 ). HA acts also as a biochemical cue enhancing chondrogenic differentiation of MSCs, promoting chondrocyte proliferation and preventing chondrocyte de-differentiation by activating CD 44 (Chen et al, 2018 ; Li et al, 2018a ; Yamagata et al, 2018 ). The use of HA in TE affects matrix deposition by cells, thus enhancing the dynamic and equilibrium moduli during in vitro culture (Levett et al, 2014 ).…”

The Contribution of Silk Fibroin in Biomedical Engineering

“…The extraordinary mechanical strength, elasticity and resistance of SF produced by B. mori are essential, especially for regenerative medicine and tissue regeneration applications [ 77 ]. Keeping this in mind, Chen et al (2018) [ 78 ] developed 3D SF-based scaffolds in order to explore the potential of this biomaterial for tracheal defect repairing. They tested in vitro and in vivo the performance of SF scaffolds by analyzing the regeneration process of tracheal epithelium.…”

“…They tested in vitro and in vivo the performance of SF scaffolds by analyzing the regeneration process of tracheal epithelium. Their data showed that SF scaffolds sustained tracheal mucosa regeneration within four weeks [ 78 ]. Another research group developed SF scaffolds by using high concentrations of SF aqueous solutions.…”