In this present study, we introduce an innovative hybrid 3D bioprinting methodology that integrates fused deposition modeling (FDM) with top–down digital light processing (DLP) for the fabrication of an artificial trachea. Initially, polycaprolactone (PCL) was incorporated using an FDM 3D printer to provide essential mechanical support, replicating the structure of tracheal cartilage. Subsequently, a chondrocyte-laden glycidyl methacrylated silk fibroin hydrogel was introduced via top–down DLP into the PCL scaffold (PCL-Sil scaffold). The mechanical evaluation of PCL-Sil scaffolds showed that they have greater flexibility than PCL scaffolds, with a higher deformation rate (PCL-Sil scaffolds: 140.9% ± 5.37% vs. PCL scaffolds: 124.3% ± 6.25%) and ability to withstand more force before fracturing (3.860 ± 0.140 N for PCL-Sil scaffolds vs. 2.502 ± 0.126 N for PCL scaffolds, ***P < 0.001). Both types of scaffolds showed similar axial compressive strengths (PCL-Sil scaffolds: 4.276 ± 0.127 MPa vs. PCL scaffolds: 4.291 ± 0.135 MPa). Additionally, PCL-Sil scaffolds supported fibroblast proliferation, indicating good biocompatibility. In vivo testing of PCL-Sil scaffolds in a partial tracheal defect rabbit model demonstrated effective tissue regeneration. The scaffolds were pre-cultured in the omentum for two weeks to promote vascularization before transplantation. Eight weeks after transplantation into the animal, bronchoscopy and histological analysis confirmed that the omentum-cultured PCL-Sil scaffolds facilitated rapid tissue regeneration and maintained the luminal diameter at the anastomosis site without signs of stenosis or inflammation. Validation study to assess the feasibility of our hybrid 3D bioprinting technique showed that structures, not only the trachea but also the vertebral bone-disc and trachea-lung complex, were successfully printed.

Background/Aim: Mesenchymal stem cells (MSCs) have been suggested as an alternative therapeutic option in atopic dermatitis. Palatine tonsils are lymphoepithelial tissue located around the oropharynx and have been proposed as one of the important alternative sources of MSCs. The purpose of this study was to evaluate the protective and therapeutic effects of tonsil-derived MSCs (TMSCs) in a 2,4-dinitrofluorobenzene (DNFB)-induced mouse model of atopic dermatitis (AD). Materials and Methods: The effect of TMSCs was evaluated in 20 C57BL/6J mice that were randomly divided into four groups (normal, DNFB-PBS, DNFB-TMSC7, and DNFB-TMSC16 group). TMSCs were subcutaneously injected into DNFB-sensitized mice on day 7 (DNFB-TMSC7 group) and day 16 (DNFB-TMSC16 group). Several parameters of inflammation were assessed. Results: Subcutaneously injected TMSCs significantly improved the inflammatory symptoms in a DNFB-induced AD model mice, particularly showing therapeutic effects rather than protective effects. TMSC treatment inhibited T-cell-mediated inflammatory responses by decreasing the levels of IL-6, IL-1β, TNF-α (Th1 cell marker), IL-4 (Th2 cell marker), and B-cell-mediated serum IgE. In contrast, TMSCs enhanced the anti-inflammatory cytokine TGF-β. Conclusion: In vitro and in vivo results suggest that TMSC treatment improved inflammatory skin lesions in the DNFB-induced AD mice model via immunomodulatory effects of the TMSCs. TMSCs inhibit T-cell and B-cell mediated responses, and enhance the anti-inflammatory responses.

Background/Aim: Allicin has been known to improve wound healing via antimicrobial and anti-inflammatory properties. The aim of this study was to evaluate whether an allicin-coated tracheal tube can prevent tracheal stenosis through improving wound healing after tracheal injury. Materials and Methods: Allicin-coated silicone tracheal tube (t-tube) was prepared by the polydopamine-mediated coating method. Tracheal mucosa was injured, and an allicin-coated t-tube was placed into the trachea to evaluate mucosal changes until designated time point. Anti-inflammatory, anti-bacterial and cytotoxic effects of allicin were also investigated in in vitro. Results: Allicin- coated silicone was not cytotoxic, and it showed anti-inflammatory and anti-bacterial effects in in vitro analysis. The use of allicin-coated t-tube in a rabbit model showed favorable mucosal healing with significant decrease of proinflammatory cytokines compared to the non-coated tube group. The allicin-coated tube showed obvious decreased number of cocci-shaped bacterial attached to the tube surface. From the histological point of view, the allicin- coated tube showed faster regeneration of the normal respiratory epithelial structure compared to the non-coated group. Conclusion: Allicin-coated t-tube showed anti-inflammatory and anti-bacterial effects on injured tracheal mucosa. We suggest that allicin-coated t-tube can be used for promoting physiological wound healing to prevent laryngotracheal stenosis.