Correlation between histone methylation level and pathological development of osteoarthritis / 浙江大学学报·医学版

Osteoarthritis is the most common degenerative cartilage disease. A large number of studies have shown the close association between epigenetics and osteoarthritis. Histone methylation is a type of epigenetic modification, and the link between histone methylation and osteoarthritis has also been revealed. In this article, we summarize the correlation between methylation levels of different histones and osteoarthritis in an attempt to explore the changes and regulation mechanisms of histone methylation in osteoarthritis. It has been shown that there are possible relations between the methylation levels of different amino acids on histone H3 and the pathological development of osteoarthritis; specifically, the rise of methylation level at the lysine 4 would aggravate the pathological development of osteoarthritis, while the the pattern of lysine 9 and 27 would be the opposite. These results indicate the possible existence of a complex network of histone methylation modifications. And the specific regulation of histone methylation levels in different positions may delay or prevent the occurrence and development of osteoarthritis.

Development of human embryonic stem cell platforms for human health-safety evaluation / 北京大学学报(医学版)

SUMMARY Thehumanembryonicstemcells(hESCs)serveasaself-renewable,genetically-healthy, pluripotent and single source of all body cells,tissues and organs.Therefore,it is considered as the good standard for all human stem cells by US,Europe and international authorities.In this study,the standard and healthy human mesenchymal progenitors,ligament tissues,cardiomyocytes,keratinocytes,primary neurons,fibroblasts,and salivary serous cells were differentiated from hESCs.The human cellular health-safety of NaF,retinoic acid,5-fluorouracil,dexamethasone,penicillin G,adriamycin,lead ace-tate PbAc,bisphenol A-biglycidyl methacrylate (Bis-GMA)were evaluated selectively on the standar-dized platforms of hESCs,hESCs-derived cardiomyocytes,keratinocytes,primary neurons,and fibro-blasts.The evaluations were compared with those on the currently most adopted cellular platforms.Parti-cularly,the sensitivity difference of PM2.5 toxicity on standardized and healthy hESCs derived fibroblasts, currently adopted immortalized human bronchial epithelial cells Beas-2B and human umbilical vein endo-thelial cells (HUVECs)were evaluated.The results showed that the standardized hESCs cellular plat-forms provided more sensitivity and accuracy for human cellular health-safety evaluation.

Expert consensus on induction of human embryonic stem cells into tenocytes / 浙江大学学报·医学版

Embryonic stem cells have unlimited proliferative capacity, which may provide a source of tendon stem/progenitor cells for tissue engineering. Experts of International Science and Technology Collaborative Program of Ministry of Science and Technology have developed a protocol consensus on differentiation of human embryonic stem cells into the tendon cells. The consensus recommends a protocol of two-step generation of human embryonic stem cells into tendon cells: the human embryonic stem cells are first differentiated into mesenchymal stem cells on different material surfaces; then with the scaffold-free tissue engineering tendon formed by high-density planting, the mesenchymal stem cells are induced into tendon cells under static or dynamic mechanical stimulation in vivo and in vitro. Tissue engineering tendon established in vitro by the protocol can be used as a model in toxicological analysis and safety evaluation of tendon-relevant small molecule compounds, medical materials and drugs.

Three-dimensional parallel collagen scaffold promotes tendon extracellular matrix formation / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of three-dimensional parallel collagen scaffold on the cell shape, arrangement and extracellular matrix formation of tendon stem cells.</p><p><b>METHODS</b>Parallel collagen scaffold was fabricated by unidirectional freezing technique, while random collagen scaffold was fabricated by freeze-drying technique. The effects of two scaffolds on cell shape and extracellular matrix formation were investigated in vitro by seeding tendon stem/progenitor cells and in vivo by ectopic implantation.</p><p><b>RESULTS</b>Parallel and random collagen scaffolds were produced successfully. Parallel collagen scaffold was more akin to tendon than random collagen scaffold. Tendon stem/progenitor cells were spindle-shaped and unified orientated in parallel collagen scaffold, while cells on random collagen scaffold had disorder orientation. Two weeks after ectopic implantation, cells had nearly the same orientation with the collagen substance. In parallel collagen scaffold, cells had parallel arrangement, and more spindly cells were observed. By contrast, cells in random collagen scaffold were disorder.</p><p><b>CONCLUSION</b>Parallel collagen scaffold can induce cells to be in spindly and parallel arrangement, and promote parallel extracellular matrix formation; while random collagen scaffold can induce cells in random arrangement. The results indicate that parallel collagen scaffold is an ideal structure to promote tendon repairing.</p>

Application of silk-based tissue engineering scaffold for tendon / ligament regeneration / 浙江大学学报·医学版

Tendon/ligament injury is one of the most common impairments in sports medicine. The traditional treatments of damaged tissue repair are unsatisfactory, especially for athletes, due to lack of donor and immune rejection. The strategy of tissue engineering may break through these limitations, and bring new hopes to tendon/ligament repair, even regeneration. Silk is a kind of natural biomaterials, which has good biocompatibility, wide range of mechanical properties and tunable physical structures; so it could be applied as tendon/ligament tissue engineering scaffolds. The silk-based scaffold has robust mechanical properties; combined with other biological ingredients, it could increase the surface area, promote more cell adhesion and improve the biocompatibility. The potential clinical application of silk-based scaffold has been confirmed by in vivo studies on tendon/ligament repairing, such as anterior cruciate ligament, medial collateral ligament, achilles tendon and rotator cuff. To develop novel biomechanically stable and host integrated tissue engineered tendon/ligament needs more further micro and macro studies, combined with product development and clinical application, which will give new hope to patients with tendon/ligament injury.

Progress on treatment of tendinopathy with platelet-enriched plasma / 浙江大学学报·医学版

Platelet-enriched plasma (PRP) contains high concentration of platelets and abundant growth factors, which is made by centrifuging of blood and separating of blood elements. PRP promotes tendon repair by releasing various cytokines to enhance cell proliferation, tenogenic differentiation, formation and secretion of matrix; meantime, it can reduce pain by inhibiting the expression of pain-associated molecules. A number of clinical studies demonstrated that PRP was effective in treatment of tendinopathy, including patellar tendinopathy, lateral epicondylitis and plantar fasciopathy. However, some studies did not support this conclusion, because of disparity of PRP types, therapeutic courses and injections protocols in clinical application. Based on its safety, PRP can be a choice of treatment for tendinopathy, in case other non-surgical therapies are of no effect.

Clinical application and research of autologous chondrocyte implant / 中华骨科杂志

ObjectiveTo investigate and evaluate the result and the possibility of the clinical application of autologous chondrocyte implant (ACI).MethodsFrom November 2007 to June 2009,6 cases of knee articular cartilage defect were treated with ACI,including 2 males and 4 females with an average age of 39.5 years (range,19-55).All the defects were located on the condyles of femur with a mean size of 7.3 cm2 (range,3.8-11.6).ACI comprises a two-stage procedure:chondrocytes are first harvested from the non-load bearing area of the joint,expand in vitro to acquire enough cells,and then the chondrocytes are implanted.The defect of cartilage were covered with bone membrane and fixed with sutures and fibrin albumen glue.Lysholm score system,International Knee Documentation Committee (IKDC) grading system,and MRI were used to evaluate the effect of ACI,6 and 12 months post-operatively.ResultsAll the patients were followed up.The clinical outcomes of the 6 and 12 months follow-ups demonstrated increased of clinical scores.The MRI follow-up showed good filling of the defect with tissue having the imaging appearance of cartilage in all patients.Only one patient suffered adhesion,because she refused to finish rehabilitation exercises as our treatment advises.ConclusionAs the clinical effect of ACI for knee cartilage defect is satisfied,the ACI may be a good choice for treating knee cartilage defect in future.It is very important to control the indications strictly and guarantee to finish the post-operative rehabilitation exercises.