Repair of urethral defects by an adipose mesenchymal stem cell‑porous silk fibroin material

Abstract

The aim of the present study was to determine whether it was possible to repair urethral defects with a material of adipose mesenchymal stem cells (ADMSCs)-porous silk fibroin (SF). A total of 39 male New Zealand white rabbits were randomly divided into a control group, an SF group and a bromodeoxyuridine (BrdU)-labeled ADMSCs-SF group (SSF group; n=13/group). Defects were made by resecting the posterior urethral wall. The defects in the SF and SSF groups were repaired using SF and BrdU-labeled ADMSCs-SF materials respectively. Then the anterior wall was sutured, and the urethral catheter was retained for 3 weeks following surgery. The catheter was rinsed with nitrofurazone once a day. The cells with positive expressions of factor VIII related antigen (FVIII-RAg), α-smooth muscle actin (α-SMA) and pan-cytokeratin (AE1/AE3) were detected by immunohistochemical assay, and the distributions of BrdU positive cells and macrophages were observed. Urethrography was performed prior to and following surgery. All rabbits had normal urethral morphologies prior to surgery. The incidence rates of postoperative complications in the control, SF and SSF groups were 76.92 (7/13), 23.07 (3/13) and 15.38% (2/13), respectively (P<0.05). The number of positive macrophages in the SSF group was significantly lower than that of the SF group 4 weeks following surgery (P<0.05). In the SSF group, BrdU positive cells were scattered within the SF material following surgery, primarily at the intersection between the SF material and the urethra. The number of FVIII-RAg positive cells in the SSF and SF groups were significantly different (P<0.05), which were also significantly higher than that of control group (P<0.01). The number of α-SMA positive cells in the SSF and SF groups were significantly different (P<0.05), and these values also significantly exceeded those exhibited by the control group (P<0.01). In addition, the SSF and SF groups had positive staining of AE1/AE3. Similar to normal urethral mucosa, the cytoplasm was stained brownish yellow (P<0.05). It is thus feasible to repair urethral defects using ADMSCs-SF material.

Ductility and Porosity of Silk Fibroin Films by Blending with Glycerol/Polyethylene Glycol and Adjusting the Drying Temperature

“…Biofunctional films (BFFs) with adjustable ductility and porous structure are useful in many applications, including medicine, sensing, , and tissue engineering . Tunable ductility is necessary for materials where forces from different directions are applied to these BFFs, and pore size as well as porosity of BFFs in cell culture and tissue engineering can have a significant impact on nutrient transport, which influences cell expansion and migration on the films. , Various synthetic materials including poly­(lactic- co -glycolic acid), poly­(methyl methacrylate), and poly­(vinyl alcohol) have been used to prepare BFFs with favorable mechanical properties, but these materials displayed either a lack of biodegradability or irritant degradation products . Hence, natural materials, such as collagen, gelatin, and silk fibroin (SF), have been investigated as candidates for tissue replacements. − However, collagen- and gelatin-based materials have excellent biological features but insufficient mechanical toughness, elasticity, and inadequate long-term stability unless additional cross-linking was applied. , SF has excellent inherent properties including biocompatibility, biodegradability, minimal toxicity and irritability, and tunable and robust mechanical properties, and can also be easily cast into films with superior permeability to dissolve oxygen in solution. ,− , …”

“…4 Tunable ductility is necessary for materials where forces from different directions are applied to these BFFs, 5 and pore size as well as porosity of BFFs in cell culture and tissue engineering can have a significant impact on nutrient transport, 6 which influences cell expansion and migration on the films. 7,8 Various synthetic materials including poly(lactic-co-glycolic acid), poly(methyl methacrylate), and poly(vinyl alcohol) have been used to prepare BFFs with favorable mechanical properties, but these materials displayed either a lack of biodegradability or irritant degradation products. 9 Hence, natural materials, such as collagen, gelatin, and silk fibroin (SF), have been investigated as candidates for tissue replacements.…”

The Fabrication and Evaluation of a Potential Biomaterial Produced with Stem Cell Sheet Technology for Future Regenerative Medicine

“…Meanwhile, ECM can provide an ideal microenvironment to accelerate circulation and exchange of oxygen and nutrient between cells and external environment. As a natural scaffold material, previous studies showed that silk fibroin could be shaped into a sheet or film to support the formation of epithelium and displayed significant advantages, including biocompatibility, moderate mechanical, properties and low cost [33][34][35]. However, like any other nonautologous biomaterials, silk fibroin can induce some adverse immunological events for its nonmammalian origin.…”

Overview of Urethral Reconstruction by Tissue Engineering: Current Strategies, Clinical Status and Future Direction

“…In such situation, seeding of biomaterials with smooth muscle cells or its progenitors would be desirable. It was also shown in another study that incorporation of mesenchymal stem cells with silk fibroin; compared to acellular silk fibroin, reduces the inflammatory reaction caused by the biomaterial and resulted in better epithelial and smooth muscle growth in the urethral defect [50]. As of the application of naturally derived scaffolds in urologic studies, Pinnagoda et al [38] reported a research in 2016 in which a 2 cm urethral defect was treated with acellular tubular graft, which was made from collagen.…”