Mesenchymal stem cells in craniofacial reconstruction: a comprehensive review.

Craniofacial reconstruction faces many challenges, including high complexity, strong specificity, severe injury, irregular and complex wounds, and high risk of bleeding. Traditionally, the "gold standard" for treating craniofacial bone defects has been tissue transplantation, which involves the transplantation of bone, cartilage, skin, and other tissues from other parts of the body. However, the shape of craniofacial bone and cartilage structures varies greatly and is distinctly different from ordinary long bones. Craniofacial bones originate from the neural crest, while long bones originate from the mesoderm. These factors contribute to the poor effectiveness of tissue transplantation in repairing craniofacial defects. Autologous mesenchymal stem cell transplantation exhibits excellent pluripotency, low immunogenicity, and minimally invasive properties, and is considered a potential alternative to tissue transplantation for treating craniofacial defects. Researchers have found that both craniofacial-specific mesenchymal stem cells and mesenchymal stem cells from other parts of the body have significant effects on the restoration and reconstruction of craniofacial bones, cartilage, wounds, and adipose tissue. In addition, the continuous development and application of tissue engineering technology provide new ideas for craniofacial repair. With the continuous exploration of mesenchymal stem cells by researchers and the continuous development of tissue engineering technology, the use of autologous mesenchymal stem cell transplantation for craniofacial reconstruction has gradually been accepted and promoted. This article will review the applications of various types of mesenchymal stem cells and related tissue engineering in craniofacial repair and reconstruction.

Topological plasmons in stacked graphene nanoribbons.

In this Letter, we theoretically study the topological plasmons in Su-Schrieffer-Heeger (SSH) model-based graphene nanoribbon (GNR) layers. We find that for the one-dimensional (1D) stacked case, only two topological modes with the field localized in the top or bottom layer are predicted to exist by the Zak phase. When we further expand the stacked 1D GNR layers to two-dimensional (2D) arrays in the in-plane direction, the topology is then characterized by the 2D Zak phase, which predicts the emergence of three kinds of topological modes: topological edge, surface, and corner modes. For a 2D ribbon array with Nx × Ny units, there are 4(Ny - 1), 4(Nx - 1), and 4 topological edge, surface, and corner modes, and the field is highly localized at the edge/surface/corner ribbons. This work offers a platform to realize topological modes in GNRs and could be important for the design of topological photonic devices such as lasers and sensors.

Adiponectin receptors activation performs dual effects on regulating myogenesis and adipogenesis of young and aged muscle satellite cells.

OBJECTIVES: Skeletal muscle mass and function deteriorate with ageing. Adiponectin receptors (APNrs), mainly activated by adiponectin, participate in various physiological activities and have varying signalling pathways at different ages. This study aimed to explore whether discrepant performance exists in APNr activation regulating young and aged muscle satellite cells (MUSCs) and whether age-related muscle dysfunction could be alleviated upon APNr activation. METHODS: The gastrocnemius muscle phenotype was observed in male mice aged 2 and 18 months. An APNr agonist (AdipoRon) was used in vitro and in vivo to investigate the changes in cell biological behaviours and whether muscle dysfunction could be retarded after APNr activation. RESULTS: Aged mice exhibited decreased muscle mass and increased fat infiltration. APNr activation inhibited C2C12 cells and young MUSCs (YMUSCs) proliferation but showed no obvious effect on aged MUSCs (AMUSCs). Moreover, APNr activation inhibited the migration of both YMUSCs and AMUSCs. Interestingly, APNr activation hampered the myogenic differentiation but advanced the adipogenic differentiation of YMUSCs, yet exact opposite results were presented in AMUSCs. It was demonstrated that Wnt and PI3K signalling pathways may mediate the phenotypic differences. Furthermore, in vivo experiments verified that APNr activation ameliorated age-related muscle atrophy and excessive fat infiltration. CONCLUSIONS: APNr activation exerted dual effects on the regulation of myogenesis and adipogenesis of YMUSCs and AMUSCs and rescued age-related skeletal muscle dysfunction.

Preparation and characterization of photocurable composite extracellular matrix-methacrylated hyaluronic acid bioink.

Producing a bioink that fulfills the physicochemical requirements of printing and provides a desirable environment for encapsulated cells is a major challenge in three-dimensional (3D) bioprinting. Thus, we have developed a biocompatible bioink (ECM@MeHA bioink) with suitable mechanical support and visible light printable properties. In this bioink system, the thermosensitive extracellular matrix (ECM) was prepared and can be crosslinked at 37 °C. And the prepared methacrylated hyaluronic acid (MeHA) can be crosslinked under visible light using the biosafe initiators (Eosin Y, TEOA, and NVP). Thus, the ECM@MeHA bioink consisted of a mix solution of ECM and MeHA containing visible light initiators can cure at 515 nm visible light for 30 s and then further crosslinked at 37 °C to form a double network hydrogel. Then, the mechanical properties and biocompatibility of ECM@MeHA hydrogel, and the printability and the cell viability of the ECM@MeHA bioink were systemically evaluated. The results showed that the mechanical property of the MeHA hydrogel is significantly improved following the addition of 10 mg mL-1 of ECM (10ECM@MeHA). The compressive strength and modulus of 10ECM@MeHA hydrogel were 102.38 ± 5.27 kPa and 782 ± 20.36 kPa, which were 2.7 times and 3.1 times higher than those of MeHA, respectively. After encapsulating MC3T3-E1 cells in the 10ECM@MeHA hydrogel for 7 days, the culture showed excellent biocompatibility. The 10ECM@MeHA bioink and cell-laden 10ECM@MeHA bioink were printed, and the cells were successfully encapsulated by the extrusion-based bioprinting and digital light processing (DLP) -based bioprinting. The cell-laden 10ECM@MeHA scaffold showed 94.27 ± 3.00% cell viability after 7 days of the 3D culture. In conclusion, 10ECM@MeHA bioink may provide a new strategy for constructing disease models or drug screening models in vitro and is expected to be widely used in the field of tissue engineering scaffolds.

Stem Cells from Human Exfoliated Deciduous Teeth and their Promise as Preventive and Therapeutic Strategies for Neurological Diseases and Injuries.

Stem cells from human exfoliated deciduous teeth (SHEDs) are relatively easy to isolate from exfoliated deciduous teeth, which are obtained via dental therapy as biological waste. SHEDs originate from the embryonic neural crest, and therefore, have considerable potential for neurogenic differentiation. Currently, an increasing amount of research is focused on the therapeutic applications of SHEDs in neurological diseases and injuries. In this article, we summarize the biological characteristics of SHEDs and the potential role of SHEDs and their derivatives, including conditioned medium from SHEDs and the exosomes they secrete, in the prevention and treatment of neurological diseases and injuries.