A novel knitted scaffold made of microfiber/nanofiber core-sheath yarns for tendon tissue engineering.

Tendon injury is common in sports and other rigorous activities, which may result in dysfunction and disability. Recently, scaffolds with a knitted structure have been widely applied for tendon tissue engineering. The purpose of this study was to fabricate a novel knitted tendon scaffold made of microfiber/nanofiber core-sheath yarns and evaluate the biocompatibility and the effect of tenogenic differentiation and tendon tissue regeneration in vitro and in vivo. Poly(ε-caprolactone) (PCL) microfibers, PCL microfibers-PCL nanofibers (PCL-PCL) and PCL microfiber-silk fibroin/poly(l-lactic acid-co-ε-caprolactone) nanofiber (SF/PLCL) core-sheath yarns were fabricated and then knitted with an automatic knitting machine to produce PCL, PCL-PCL and PCL-SF/PLCL fabric scaffolds. The characterization of the scaffolds was performed by using scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy and an universal mechanical instrument. The in vitro experiment showed that rabbit bone marrow stem cells seeded on the scaffolds exhibited an elongated morphology and proliferated better in the PCL-SF/PLCL group, as compared to the PCL and PCL-PCL groups. Moreover, the PCL-SF/PLCL scaffold promoted the tenogenic differentiation of the cells for the highest expression levels of the tendon-related genes through down-regulating p-ERK1/2 expression among the three groups. Furthermore, the in vivo study in a rabbit patellar defect model demonstrated that the PCL-SF/PLCL scaffold could enhance the tissue regeneration and remodeling process as indicated by the better structural and biomechanical properties according to the results of histology, immunohistochemistry, transmission electron microscope examination and biomechanical tests. Therefore, the PCL-SF/PLCL scaffold is proved to be a promising biomaterial for tendon tissue engineering and a potential candidate for clinical treatment of tendon injury in the future.

A novel elastic and controlled-release poly(ether-ester-urethane)urea scaffold for cartilage regeneration.

In the tissue engineering of cartilage, scaffolds with appropriate elasticity and controlled-release properties are essential. Herein, we synthesized a poly(ether-ester-urethane)urea scaffold with a pendant amino group (PEEUUN) through a de-protection process from PEEUU-Boc polymers and grafted kartogenin (KGN) onto the PEEUUN scaffolds (PEEUUN-KGN). Characterization, performance tests, scaffold biocompatibility analysis, and chondrogenesis evaluation both in vitro and in vivo were conducted. The results revealed that the PEEUUN-KGN scaffolds were degradable and three-dimensional (3D) with interconnected pores, and possessed good elasticity, as well as excellent cytocompatibility. Meanwhile, KGN on the PEEUUN-KGN scaffolds underwent stable sustained release for a long time and promoted human umbilical cord mesenchymal stem cells (HUCMSCs) to differentiate into chondrocytes in vitro, thus enhancing cartilage regeneration in vivo. In conclusion, the present PEEUUN-KGN scaffolds would have application potential for cartilage tissue engineering.

New advances in liver decellularization and recellularization: innovative and critical technologies.

Techniques for producing decellularized scaffolds for use in liver tissue engineering are emerging as promising methods for tissue reconstruction. In this article, the authors present an overview of liver decellularization methods developed and applied in recent years. These include the widespread use of various perfusion methods for the generation of a 3D scaffold, which may function as a template for either cell recellularization or direct biological application. The authors evaluate methods for scaffold production and explore some factors that may affect the decellularization process. In addition to tissue engineering, this overview includes a description of other potential applications for a decellularized liver scaffold. The authors also introduce the concept of fabrication of fragile biomaterial architecture and finally review the cell types applied to liver scaffold engineering.

Factors associated with efficacy of pegylated interferon-α plus ribavirin for chronic hepatitis C after renal transplantation.

Hepatitis C virus (HCV) infection is the major cause of chronic liver disease after renal transplantation (RT), which reduces both graft and patient survival. After RT, the most widely used approach is interferon (IFN)-based therapy of hepatitis C which may be unsatisfactory with both poor efficacy and an increasing risk of allograft rejection. Thus, it is not recommended unless patients develop fibrosing cholestatic hepatitis. Several recent studies, however, suggest that treatment was possible with preservation of both renal and liver functions. From the limited studies on HCV infection after RT, several factors have been identified as important tools for the management of therapy in these patients. Infection with HCV genotypes 2 and 3, low baseline viral load and absence of advanced fibrosis/cirrhosis in the liver are associated with a sustained virologic response (SVR). After initiation of treatment, initial viral decline with undetectable HCV-RNA at week 4 of therapy (RVR) is the best predictor of SVR independent of HCV genotype. Furthermore, some factors must be taken into consideration in order to avoid allograft rejection, such as the time between transplantation and therapy for HCV, the dose and duration of regimen and renal function. Careful evaluation of predictions of stable renal function and SVR for those patients helps to reduce inefficient treatment regimes and to increase the cure rate in addition to reducing the possible risk. In this review, the latest information was collected and we focus on the discussion of the factors influencing the attainment of SVR after RT.