Identification of nontuberculous mycobacteria isolated from household showerheads of patients with nontuberculous mycobacteria.

This study aimed to examine whether nontuberculous mycobacteria (NTM) inside household showerheads are identical to those in patients with NTM-pulmonary disease (PD) since household water is one of the potential NTM sources. Samples were obtained from 32 household showerheads of patients with NTM-PD recruited through the Pulmonary Outpatient Department at the Severance Hospital between October 2018 and October 2019. All isolates from patients with NTM-PD were diagnosed using a reverse-hybridization line probe assay based on the ropB gene. To determine the mycobacterial compositions, the washing fluids were collected and investigated using multiplex polymerase chain reaction assay and NTM culture; suspected microbial isolates in these fluids and culture were identified using sequencing analysis of 16S rRNA gene. NTM species causing the PD in the patients were Mycobacterium avium, M. intracellulare, M. abscessus, M. massiliense, and M. fortuitum complex. The mycobacteria isolated from the showerhead were M. lentiflavum, M. gordonae, M. triplex, M. phocaicum, M. mucogenicum, M. florentinum, M. gilvum, M. llatzerense, and M. peregrinum. However, the species identified in the showerheads did not match those of the patients. Despite NTM species in the showerheads, clinical implications in the main pathogenesis associated with the disease in the patients studied were not elucidated.

Characterization of surface modified glycerol/silk fibroin film for application to corneal endothelial cell regeneration.

Corneal endothelial cells (CEnCs) play a fundamental role in maintaining the transparency of the cornea. CEnCs lose their full proliferating capacity when tissue damages occur. The loss in proliferation rate is associated with corneal edema and decrease in visual acuity, leading in severe cases, to blindness. In these situations, a corneal transplant is usually needed to restore the original tissue functions. Tissue engineering is an efficient alternative for the production of implantable films, which can regenerate the tissue functions regulating at the same time the immune-response. In this study, we proposed a stable and transparent film, composed of silk fibroin modified with glycerol (G/SF), as a potential substrate for corneal endothelial cells regeneration. Our results confirmed that G/SF films have a uniform structure, rougher surface and lower thickness respect to the SF film. In vitro tests show that G/SF films can induce a slight increase in CEnCs initial adhesion and proliferation rate if compared with the SF film. Morphology and gene expression evaluations demonstrated that the bioactive effects of silk fibroin were not affected by the presence of glycerol. For this reason, the G/SF films are suitable as CEnCs carrier and promising for the corneal damages treatments.

Functionalized silk fibroin film scaffold using ß-Carotene for cornea endothelial cell regeneration.

Design of corneal endothelium substitute is important for replacement of cadaveric cornea tissue. Our previous study has shown the suitability of silk fibroin (SF) as a biomaterial for cornea scaffold. In this study, we used ß-Carotene (ß-C) to enhance the regeneration of corneal endothelial cells (CEnCs) and maintain CEnC specific function. The fabricated film scaffolds showed desired transparency and hydrophilic properties which are crucial factors for vision recovery. The cell viability, phenotype and gene expression was examined using MTT assay, immunofluorescence and reverse transcription polymerase chain reactions. Compared with pristine SF scaffold, proper amount of ß-C incorporated with SF scaffolds showed higher initial cell attachment, cell viability and mRNA expression. The results indicate that the fabricated SF film scaffold incorporated with small amount of ß-C might be the suitable alternative corneal endothelium substitute for transplantation.

Bioengineered porous composite curcumin/silk scaffolds for cartilage regeneration.

Articular cartilage repair is a challenge due to its limited self-repair capacity. Cartilage tissue engineering supports to overcome following injuries or degenerative diseases. Herein, we fabricated the scaffold composed of curcumin and silk fibroin as an appropriate clinical replacement for defected cartilage. The scaffolds were designed to have adequate pore size and mechanical strength for cartilage repair. Cell proliferation, sulfated glycosaminoglycan (sGAG) content and mRNA expression analysis indicated that chondrocytes remained viable and showed its growth ability in the curcumin/silk scaffolds. Especially, in 1mg/ml curcumin/silk scaffold showed higher cell viability rate and extracellular matrix formation than other experimental groups. Furthermore, curcumin/silk scaffold showed its biocompatibility and favorable environment for cartilage repair after transplantation in vivo, as indicated in histological examination results. Overall, the functional composite curcumin/silk scaffold can be applied in cartilage tissue engineering and promising substrate for cartilage repair.

Bioengineered Osteoinductive Broussonetia kazinoki/Silk Fibroin Composite Scaffolds for Bone Tissue Regeneration.

In this article, Broussonetia kazinoki (BK) powdery extract is utilized to modify the silk fibroin (SF) scaffold and applied to the bone defect area. The BK/SF scaffold is an efficient cell carrier which promotes cell proliferation and osteogenic differentiation of rBMSCs (bone marrow derived mesenchymal stem cells). We confirmed biocompatibility and osteogenic differentiation capacity of BK/SF scaffolds compared to pristine SF scaffold in both in vitro and in vivo evaluation. Gene expression related to osteogenic differentiation and bone regeneration significantly upregulated in the BK/SF scaffold group. The implanted scaffolds were attached well to the surface of the bone defect region and integrated with surrounding tissues without significant inflammatory reaction. Furthermore, almost 45% of bone volume has been recovered at 8 weeks postsurgery, while the SF and control group showed 20% recovery. These results suggest that BK powdery extract incorporated with an SF scaffold might be a suitable substitute for an alternative bone graft for bone regeneration.

Nature-Derived Aloe Vera Gel Blended Silk Fibroin Film Scaffolds for Cornea Endothelial Cell Regeneration and Transplantation.

The goal of this study was to fabricate an appropriate replacement for cadaveric corneas to overcome a shortage of cadaveric corneas for transplantation. In this study, we fabricated transparent ultrathin film scaffolds with nature-derived aloe vera (AV) gel and silk fibroin (SF) for corneal endothelial cells (CECs). The scaffolds were subjected to analysis of transparency and contact angle using field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy to determine their physical and chemical properties. FESEM images revealed that the critical morphology of CECs was formed on the AV gel in the blend with SF rather than in the scaffold with SF alone. The cell proliferation, phenotype, and specific gene marker expressions for CECs were determined by MTT assays, immunofluorescence, and reverse transcription polymerase chain reactions. Incorporation of a small amount of AV gel increased the cell viability and maintained its functions well. The scaffolds were easily handled for transplantation into rabbit eyes with small incisions and examined by their transparency after transplantation and histological staining. The scaffolds attached to the surface of the corneal stroma and integrated with surrounding corneal tissue without a significant inflammatory reaction. These results indicate that AV blended SF film scaffolds might be a suitable substitute for alternative corneal grafts for transplantation.