Hypoxic microenvironment always exists in solid tumors, and it closely relates to the development and metastasis of solid tumor. As a main transcription factor responding to hypoxic environment, hypoxia-inducible factor (HIF) can promote tumor cell proliferation, survival, angiogenesis, and epithelial-mesenchymal transition (EMT), etc. EMT is a biological process that epithelial phenotype was transformed into mesenchymal phenotype, which is mainly associated with its signaling pathways, transcription factors, inflammatory factors and miRNAs, and plays a vital role in tumor invasion and metastasis. This paper summarizes the effects of hypoxia signaling pathway, Wnt/β-catenin signaling pathway, Notch signaling pathway, NF-κB signaling pathway, Hedgehog (Hh) signaling pathway and PI3K/Akt signaling pathway on the EMT of tumor cells.
Bone tissue engineering is considered as one of the most promising way to treat large segmental bone defect. When constructing bone tissue engineering graft in vitro, suitable bioreactor is usually used to incubate cell-scaffold complex under perfusion to obtain bone tissue engineering graft with good repair efficiency. However, the theoretical model for growth rate of single cell (especially for stem cell) during this process still has many defects. The difference between stem cells and terminally differentiated cells is always ignored. Based on our previous studies, this study used self-made perfusion apparatus to apply different modes and strengths of fluid shear stress (FSS) to the cells seeded on scaffolds. The effects of FSS on the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) were investigated. The regression analysis model of the effect of FSS on the single-cell growth rate of MSCs was further established. The results showed that 0.022 5 Pa oscillatory shear stress had stronger ability to promote proliferation and osteogenic differentiation of MSCs, and the growth rate of a single MSC cell under FSS was modified. This study is expected to provide theoretical guidance for optimizing the perfusion culture condition of bone tissue engineering grafts in vitro.
Natural collagen peptides are collagen hydrolysates. Because of their unique physicochemical properties and excellent biological activities, collagen peptides have been a research hotspot of cosmetic raw materials development and skincare efficacy improvement. Combined with the needs of the skincare efficacy and the development trends of cosmetics, the extraction methods and their structural characteristics of natural collagen peptides were summarized in detail. The applications and its research progress in skincare efficacy of collagen peptides, such as moisturizing and anti-wrinkle, trophism and anti-aging, filling and skin regeneration were expressed with emphasis. Finally, the development and practical applications in cosmetics of natural collagen peptides were adequately prospected.
Mechano growth factor (MGF) is an autocrine/paracrine factor and sensitive to mechanical stimulation. MGF can be highly expressed in various soft tissues under physical stimuli, biochemistry stimuli or in damaged situation. MGF may "compensate" the stress for tissue in the processing of tissue repair. MGF can effectively accelerate the repair of the soft tissue by promoting the proliferation, migration and differentiation of cells. This paper summarizes the MGF expressions in different soft tissues and their functions in soft tissue repair. The paper also discusses current problems and challenges in using MGF to repair the soft tissue.
This study was aimed to design a new, accurate and easy-to-use water bath cryo-jaw, and try to solve the problems met in small animals achilles tendon mechanical testing. The muscle-tendon-bony units were fixed in the clamps. SD rats achilles tendon were randomly divided into group A and B. Group A was tested by the newly designed water bath cryo-jaw, while group B was treated by non-water bath cryo-jaw. The mechanical tests revealed that non of the samples of the newly-designed water bath cryo-jaw in group A slipped and fell off, and the achilles tendons were in a physiologically active state, but one of the group B samples slipped and fell off, and the others had the frozen phenomenon obviously. The maximum stress, fracture displacement and Young's modulus of the rats in group A were significantly different compared to those in group B (P<0.05). In conclusion, the new water bath cryo-jaw has more advantages than traditional ones. It exhibits a good simulation in vivo in the environmental conditions for testing the mechanical properties of the achilles tendon.