BACKGROUND:Articular cartilage repair has been a difficulty in the clinical setting, which is mainly treated with autologous or al ogeneic osteochondral grafts, and cartilage periosteum or periosteum grafts. However, the limited source, secondary lesion and immunological rejection force some researchers to search for a novel treatment strategy, cartilage tissue engineering, that is of great significance for cartilage regeneration and repair. OBJECTIVE:To investigate the tissue-engineered scaffolds for the repair of articular cartilage defects. METHODS:The first author searched the PubMed and WanFang databases for the articles addressing tissue-engineered cartilage for articular cartilage defects published between 1991 and 2015 using the keywords“articular cartilage defect, scaffold, tissue engineered cartilage”in English and Chinese, respectively. The irrelative and repetitive literatures were excluded. RESULTS AND CONCLUSION:Final y 48 eligible literatures were enrol ed based on the inclusion and exclusion criteria. Cartilage tissue engineering possesses the advantages of control ability, little damage to tissue itself, and biological repair of injured cartilage. Tissue-engineered scaffold material is a critical factor in tissue engineering construction;therefore, it should hold biodegradability and histocompatibility. The commonly used scaffold materials include natural macromolecule materials (col agen, silk fibroin and chitosan), and synthetic polymer materials (polylactic acid and tricalcium phosphate). It is necessary to prepare composite scaffolds with high bioactivity integrate advantages of each material. The tissue engineering is bound to be a hotspot in the field of articular cartilage repair.

BACKGROUND:In recent years, repair of articular cartilage injury has become an important field in basic medical research. Because injured articular cartilage is difficult to repair, the repair of articular cartilage injury has become a difficult hotspot.

BACKGROUND:Mesenchymal stem cels, underin vivo orin vitro specific induction conditions, can differentiate into the cartilage, muscle, tendons and so on. Clinical trials concerning mesenchymal stem cels mainly include tissue repair (such as bone, cartilage and joint repair) and treatment of heart, liver, spinal cord injury and nervous system diseases.
OBJECTIVE:To compare the biological characteristics of mesenchymal stem cels from different sources.
METHODS: PubMed and CNKI databases were retrieved for articles related to sources of mesenchymal stem cels and biological characteristics of mesenchymal stem cels published from 1987 to 2015. The retrieved articles were summarized and analyzed in the folowing aspects: cel surface marker, proliferation, differentiation, migration, and function, so as to explore the merits and demerits of mesenchymal stem cels from different sources.
RESULTS AND CONCLUSION:A difference in the proliferation ability and surface markers is found between different sources of mesenchymal stem cels. Immunological competence of mesenchymal stem cels from different sources may be correlated with their activation status, species differences, tissue sources and culture conditions, resulting the immunological competence of mesenchymal stem cels from different sources is not exact the same. In-depth understanding of the factors and mechanisms by which influence the migration of mesenchymal stem cels from different sources can enhance the migration ability of different sources of mesenchymal stem cels, and increase their efficiency in wound healing, tissue repair and regeneration treatment.

BACKGROUND:Studies have found that vascular endothelial growth factor and hypoxia inducible factor are involved in the development process of osteoarthritis, but their correlation is rarely reported. OBJECTIVE:To observe the expression and correlation of hypoxia inducible factor-2α and vascular endothelial growth factor in chondrocytes of articular cartilages in human osteoarthritis. METHODS: Articular cartilage specimens were colected from 50 patients with knee osteoarthritis undergoing total knee joint replacement. According to the joint Kelgren-Lawrance (K-L) X-ray grouping classification standard, there were 18 cases of K-LIII level and 32 cases of K-LIV level. Besides, articular cartilage specimens from 10 patients undergoing amputation for legs tumor or traffic accident served as control group. Hematoxylin-eosin staining, Safranin O-Fast Green staining and Mankin scoring were performed to observe and evaluate the histological characteristics of articular cartilages of each group, immunohistochemical staining was conducted to detect the expression of hypoxia inducible factor-2α and vascular endothelial growth factor in chondrocytes of articular cartilages, and their correlations were analyzed. RESULTS AND CONCLUSION:The Mankin score of K-LIV group was significantly higher than those of K-LIII group and control group. Immunohistochemical staining revealed that the number of chondrocytes with positive expression of hypoxia inducible factor-2α or vascular endothelial growth factor in K-LIV group was significantly higher than that in K-LIII group and control group (P < 0.05). The expression of hypoxia inducible factor-2α and vascular endothelial growth factor increased in chondrocytes of articular cartilages of osteoarthritis patients, and to up-regulate the expression of vascular endothelial growth factor may be the regulatory mechanism of hypoxia inducible factor-2αinthe pathogenesis of osteoarthritis.

BACKGROUND:Osteoarthritis is a joint disease that primarily affects the cartilage. With the changes of the extracelular matrix, chondrocytes appear to have apoptosis. Vascular endothelial growth factor plays an important role in promoting endothelial cel division and proliferation and inducing angiogenesis. Hypoxia-inducible factor is a celular transcription factor and produces different reactions due to the oxygen content. Vascular endothelial growth factor and hypoxia-inducible factor are focused on inhibiting chondrocyte apoptosis. OBJECTIVE:To elaborate the effects of vascular endothelial growth factor and hypoxia-inducible factors on chondrocyte apoptosis. METHODS: Recent literatures related to chondrocyte apoptosis were summarized and analyzed. During the process of osteoarthritis, changes in vascular endothelial growth factors in chondrocytes and regulatory effects of vascular endothelial growth factor and hypoxia-inducible factor on chondrocyte apoptosis were elaborated.