Construction of developmentally inspired periosteum-like tissue for bone regeneration

The periosteum, a highly vascularized thin tissue, has excellent osteogenic and bone regenerative abilities. The generation of periosteum-mimicking tissue has become a novel strategy for bone defect repair and regeneration, especially in critical-sized bone defects caused by trauma and bone tumor resection. Here, we utilized a bone morphogenetic protein-2 (BMP-2)-loaded scaffold to create periosteum-like tissue (PT) in vivo, mimicking the mesenchymal condensation during native long bone development. We found that BMP-2-induced endochondral ossification plays an indispensable role in the construction of PTs. Moreover, we confirmed that BMP-2-induced PTs exhibit a similar architecture to the periosteum and harbor abundant functional periosteum-like tissue-derived cells (PTDCs), blood vessels, and osteochondral progenitor cells. Interestingly, we found that the addition of chondroitin sulfate (CS), an essential component of the extracellular matrix (ECM), could further increase the abundance and enhance the function of recruited PTDCs from the PTs and finally increase the regenerative capacity of the PTs in autologous transplantation assays, even in old mice. This novel biomimetic strategy for generating PT through in vivo endochondral ossification deserves further clinical translation.

Evaluation of the necessity of laparoscopic repair of a uterine scar defect for cesarean scar pregnancy

Objective This study aimed to determine the risk factors associated with the necessity of laparoscopic scar defect repair for cesarean scar pregnancy (CSP). Methods We retrospectively analyzed 237 patients with CSP who were treated by ultrasound-guided suction curettage and/or laparoscopy in our hospital from April 2012 to November 2019. A total of 199 of these patients underwent ultrasound-guided suction curettage without uterine scar defect repair, while 38 of these patients underwent laparoscopic resection and uterine scar defect repair. We analyzed various clinical variables and compared the efficacy of treatment between the two groups. Results Gestational age, the maximum transverse diameter (MTD) of the gestational sac, myometrial thickness, the operation time, intraoperative blood loss, and the duration of the hospital stay were significantly different between the two groups. Gestational age, the MTD of the gestational sac, and myometrial thickness were independent risk factors for laparoscopic repair. Conclusions Gestational age, the MTD of the gestational sac, and myometrial thickness are important factors associated with the necessity for laparoscopic repair of a uterine scar defect.

Mussel inspired injectable chitosan hydrogel modified with catechol for cell adhesion and cartilage defect repair

Repairing articular cartilage defect is a great challenge due to the poor self-regenerative capability of cartilage. Hydrogel-based tissue engineering has been considered as an effective strategy. In this study, inspired...

Study on the Evolution of Graphene Defects and the Mechanical and Thermal Properties of GNPs/Cu during CVD Repair Process

Graphene has extremely high theoretical strength and electrothermal properties, and its application to Cu-based composites is expected to achieve a breakthrough in the performance of existing composites. As a nano-reinforced body, graphene often needs a long time of ball milling to make it uniformly dispersed, but the ball milling process inevitably brings damage to the graphene, causing the performance of the composite to deviate from expectations. Therefore, this paper uses CH4 as a carbon source to repair graphene through a CVD process to prepare low-damage graphene/Cu composites. The process of graphene defect generation was studied through the ball milling process. The effects of defect content and temperature on the graphene repair process were studied separately. The study found that the graphene defect repair process, the decomposition process of oxygen-containing functional groups, and the deposition process of active C atoms existed simultaneously in the CVD process. When the repair temperature was low, the C atom deposition process and the oxygen-containing functional group decomposition process dominated. In addition, when the repair temperature is high, the graphene defect repair process dominated. 3 wt% graphene/Cu composites were prepared by pressure infiltration, and it was found that the bending strength was increased by 48%, the plasticity was also slightly increased, and the thermal conductivity was increased by 10–40%. This research will help reduce graphene defects, improve the intrinsic properties of graphene, and provide theoretical guidance for the regulation of C defects in composites.

Hydrogel contained valproic acid accelerates bone-defect repair via activating Notch signaling pathway in ovariectomized rats

The purpose was to observe whether valproic acid (VPA) has a positive effect on bone-defect repair via activating the Notch signaling pathway in an OVX rat model. The MC3T3-E1 cells were cocultured with VPA and induced to osteogenesis, and the osteogenic activity was observed by alkaline phosphatase (ALP) staining, Alizarin Red (RES) staining and Western blotting (WB). Then the hydrogel-containing VPA was implanted into the femoral epiphysis bone-defect model of ovariectomized (OVX) rats for 12 weeks. Micro-CT, biomechanical testing, histology, immunofluorescence, RT-qPCR, and WB analysis were used to observe the therapeutic effect and explore the possible mechanism. ALP and ARS staining and WB results show that the cell mineralization, osteogenic activity, and protein expression of ALP, OPN, RUNX-2, OC, Notch 1, HES1, HEY1, and JAG1 of VPA group is significantly higher than the control group. Micro-CT, biomechanical testing, histology, immunofluorescence, and RT-qPCR evaluation show that group VPA presented the stronger effect on bone strength, bone regeneration, bone mineralization, higher expression of VEGFA, BMP-2, ALP, OPN, RUNX-2, OC, Notch 1, HES1, HEY1, and JAG1 of VPA when compared with OVX group. Our current study demonstrated that local treatment with VPA could stimulate repair of femoral condyle defects, and these effects may be achieved by activating Notch signaling pathway and acceleration of blood vessel and bone formation.