ObjectiveTo review the advances in utilizing paracrine effect of stem cells in knee osteoarthritis (OA) treatment.MethodsThe researches in applying stem cells derived conditioned medium, extracellular matrix, exosomes, and microvesicles in knee OA treatment and cartilage repair were reviewed and analyzed.ResultsThe satisfying outcomes of using different products of stem cells paracrine effect in knee OA condition as well as cartilage defect is revealed in studies in vitro and in vivo. The mechanism including suppressing the intraarticular inflammation, the apoptosis of chondrocytes, and the degradation of cartilage matrix, while enhancing the synthesis of cartilage matrix, the differentiation of in-situ stem cells into chondrocytes and the migration to the affected area. The effectiveness can be further improved supplemented with the tissue engineering methods or gene modification.ConclusionCompared with the traditional stem cell therapy, applying the products from paracrine effect of stem cells in knee OA treatment is more economical and safer, presenting great potential in clinical practice.
OBJECTIVE: To investigate the selection and manufacture of ideal extracellular matrix materials in bone tissue engineering. METHODS: The recent literatures about biodegradable polymers served as culture scaffolds of osteoblasts were widely reviewed, the advantages and disadvantages of biodegradable synthetic polymers and natural polymers were analysed. RESULTS: The ideal extracellular matrix material in bone tissue engineering should be made up of inorganic materials, synthetic polymers and natural polymers, which possesses morphological structure of three-dimensional foam with self-mediated drug slow delivery system of bone growth factors. CONCLUSION: The design and manufacture of combined extracellular matrix materials in bone tissue engineering is a very important and urgent challenge.
OBJECTIVE: To review the role of matrix metalloproteinase-1 (MMP-1) in the course of healing in wounded skin. METHODS: The recent literatures on MMP-1 in skin wound repair were reviewed, which gave the insight into the local effect of MMP-1 during re-epithelialization. RESULTS: Following injury, basal keratinocytes, moving from the wound edge and interact with dermal matrix proteins in the wound bed, were induced to express MMP-1 in a specific space-time pattern. MMP-1 cleaved the collagen, thereby altering its structure and affinity by which the keratinocytes binded it. MMP-1 served a beneficial role in wound healing by facilitating the proliferation and movement of keratinocytes over the collagen-rich wound bed during re-epithelialization. CONCLUSION: MMP-1 expression of migrating keratinocytes directly influences the re-epithelialization during the course of healing of the wounded skin.
Objective To evaluate an effect of the vascularendothelial growth factor (VEGF) geneactivated matrix (GAM) on repair of the sciatic nerve defect in rats. Methods The peripheral nerve extracellular matrix（ECM） was harvested by the chemical extraction from 30 SD rats. The VEGF-GAM comprised of ECM and the plasmids encoding VEGF. Thirty adult Wistar rats were made as a model of the asciatic nerve defect and were randomly divided into the following 3 groups(n=10): Group A (VEGF-GAM conduits), Group B (ECM conduits),and Group C (autografts). At 12 weeks, the rats from each groupwere subjected to an inspection for the walking tract analysis and electrophysiological and histomorphological studies.Results The VEGF DNA could be retained in GAM, promoting the transgene expressing in the sciatic nerve, and more importantly, in the axotomized neurons in the spinal cord for 12 weeks. The motor neuron recovery rate in Group A (79.13％±2.53％) was similar to that in Group C (75.26％±4.48％, Pgt;0.05), but significantly better than that in Group B (56.09％±1.89％, Plt;0.01). The number of the regenerationaxons in the distal sciatic nerve in Group A (13 463±794/mm2) was significantly lower than that in Group C (16 809±680/mm2, Plt; 0.01), but significantly higher than that in Group B (10 260±1 117/mm2,Plt;0.01). The motor nerve conduction velocity in Group A (16.44±1.65 m/s) was significantly lowerthan that in Group C (23.79±2.75 m/s, Plt;0.01), but significantly higherthan that in Group B (12.8 ±1.42 m/s, Plt;0.01). The recovery rate of thegastrocnemius muscle wet weight in Group A (71.40％±3.05%) was significantlylower than that in Group C (87.00％±1.87％,Plt;0.01), but significantly higher than that in Group B (50.00％±4.90％, Plt;0.01). The sciatic nerve function index in Group A （39.37%±4.81%） was significantly lower 〖KG6〗than that in Group C (26.27%±2.71%, Plt;0.01), but significantly higher than that in Group B (4693％±296％, Plt;0.01). Conclusion The results indicate that VEGF-GAM as a bridge can promote the functional recovery of the defected sciatic nerve in rats, but the effect is not so good as that by autografts.
Objective To develop a new method for a tissue engineered vascular graft by combining endothelial cells and an acelluarized allogenic matrix. Methods Acellularized matrix tubes were obtained by a 0.1% trypsin and 0 02% EDTA solution for 24 hours and 1% Triton X 100 for 176 hours, respectively. Endothelial cells were isolated from alloaorta and expanded in vitro. Finally, the inner surface of acellularized matrix was reseeded with endothelial cells. Acellularity and reseeding were analysed by light microscopy and scanning electron microscopy. Results The acellularization procedure resulted in an almost complete removal of the original cells and the loose three-dimensional (3D) matrix. The acellular matrix could be reseeded with expanded endothelial cells in vitro, and endothelial cells had the potential of spread and proliferation. Conclusion Acellular matrix produces by Tritoon X-100 and trypsin possesses satisfactory biocompatibility for allogenic endothelial cell. Vascular grafts can be generated in vitro by a combination of endothelial cells and allogenic acelluarized matrix.
OBJECTIVE: To investigate the effects of trace elements on the metabolism of extracellular matrix and explore the physiological and pathological mechanism of trauma. METHODS: Based on the experimental and clinical data, it was studied that the action of trace elements in the metabolism of extracellular matrix in trauma repairing. RESULTS: During wound healing, the trace elements were the components of many kinds of enzymes, carriers and proteins. They took part in the synthesis of hormones and vitamins as well as the transmission of information system. They activated many different kinds of enzymes and regulate the levels of free radicals. The trace elements had the complicated effects on the synthesis, decompose, deposition and reconstruction of collagen and other extracellular matrix. CONCLUSION: The trace elements play an important role in regulating the metabolism of extracellular matrix.
Abstract： Objective To investigate the extracellular matrix （ECM） gene expression profile of saphenous vein （SV） in end-stage renal disease （ESRD） patients undergoing coronary artery bypass grafting （CABG）. Methods Sixty-eight patients who were diagnosed as coronary artery disease by coronary angiography and admitted to Department of Cardiovascular Surgery，Zhongshan Hospital of Fudan University from July 2004 to December 2010 were enrolled in this study. According to whether or not they had preoperative ESRD history，all the 68 patients were divided into 2 groups，the ESRD group with 30 ESRD patients who needed maintenance hemodialysis，and the control group with 38 patients without preoperative renal disease. Preoperative clinical data of all the patients were collected in detail. SV samples were obtained at the time of CABG. Microarray，immunohistochemistry and Western blotting were used to investigate the expression profile of ECM genes of SV in ESRD patients undergoing CABG. Results There was no statistical difference in preoperative clinical variables between the 2 groups except the variables which were directly related to their kidney disease （P＞0.05）. There were 16 genes that were up-regulated at least 3-fold and 3 genes that were down-regulated at least 3-fold in the ECM gene expression profile of SV in the ESRD group patients before CABG. The expressions of matrix metalloproteinases-2 （MMP-2） and matrix metalloproteinases-9 （MMP-9） of the ESRD group were significantly higher than those of the control group （2.60±0.50 vs. 0.70±0.16，1.80±0.40 vs. 0.60±0.15，P＜0.01）. The expressions of tissue inhibitor of metalloproteinase-2 （TIMP-2） and tissue inhibitor of metalloproteinase-3 （TIMP-3） of the ESRD group were significantly lower than those of the control group （0.60±0.19 vs. 2.20±0.30，0.90±0.28 vs. 2.40±0.70，P＜ 0.05）. Conclusion A variety of ESRD-related risk factors of cardiovascular diseases may severely influence on the balance of ECM gene expression of SV before CABG，and the resulting imbalance is a risk factor to aggravate SV graft disease after CABG.
Objective Mechanical stimulation and inductive factors are both crucial aspects in tissue engineered cartilage. To evaluate the effects of mechanical stimulation combined with inductive factors on the differentiation of tissue engineered cartilage. Methods Bone marrow mesenchymal stem cells (BMSCs) were isolated from newborn porcine (aged7 days and weighing 3-6 kg) and expanded in vitro. The BMSCs at passage 2 were seeded onto a scaffold of poly (lactic-coglycol ic acid) (PLGA) in the concentration of 5 × 107/mL to prepare cell-scaffold composite. Cell-scaffold composites were cultivated in a medium with chondrocyte-inducted factors (group A), in a vessel with mechanic stimulating only (group B), or mechanic stimulating combined with chondrocyte-inducted factors (group C) (parameters of mechanics: 1 Hz, 0.5 MPa, and 4 hours/day). Cell-scaffold composite and auto-cartilage served as positive control (group D) and negative control (group E), respectively. After 4 weeks of cultivation, the thickness, elastic modulus, and glycosaminoglycan (GAG) content of composites were measured. Additionally, BMSCs chondrogenic differentiation was assessed via real-time fluorescent quantitative PCR, immunohistochemistry, and histological staining. Results The thickness, elastic modulus, and maximum load in group C were significantly higher than those in groups A and B (P lt; 0.05). In groups A, B, and C, cartilage lacuna formation, GAG expression, and positive results for collagen type II were obsersed through HE staining, Safranin-O staining, and immunohistochemistry staining. The dyeing depth was deeper in group A than in group B, and in group C than in groups A and B; group C was close to group E. The GAG content in group C was significantly higher than that in groups A and B (P lt; 0.05). Real-time fluorescent quantitative PCR revealed that mRNA expressions of collagen type I, collagen type II, and GAG in group C were significantly higher than those in groups A and B (P lt; 0.05), and in group A than in group B (P lt; 0.05). Conclusion Mechanical stimulation combined with chondrocyte inductive factors can enhance the mechanical properties of the composite and induce higher expression of collagen and GAG of BMSCs.
OBJECTIVE To investigate the methods to fabricate repair materials of tissue engineered peripheral nerve with bioactivity of Schwann cells (SC). METHODS 1. The materials were made by dry-wet spinning process to fabricate PLA hollow fiber canal with external diameter of 2.3 mm, internal diameter of 1.9 mm, thickness of 0.4 mm, pore size of 20 to 40 microns, pore ratio of 70% and non-spinning fiber net with pore size of 100 to 200 microns, pore ratio of 85%. 2. SC were implanted into excellular matrix (ECM) gel to observe the growth of SC. 3. SC/ECM complex were implanted into non-spinning PLA fiber net to observe the growth of SC. 4. SC, SC/ECM and SC/ECM/PLA were implanted into PLA hollow fiber canal to bridge 10 mm defect of rat sciatic nerve. RESULTS 1. SC were recovered bipolar shape at 1 day after implantation, and could be survived 14 days in ECM gel. 2. After SC/ECM complex was implanted into PLA net, most of SC were retained in the pore of PLA net with the formation of ECM gel. SC could be adhered and grown on PLA fiber. 3. Most of SC in ECM gel could be survived to 21 days after transplantation. Survival cell numbers of SC/ECM and SC/ECM/PLA groups were obviously higher than SC suspension group. CONCLUSION Non-spinning PLA porous biodegradable materials with ECM is benefit for SC to be adhered and grown.
OBJECTIVE: To investigate the preparation of bone acellular extra-cell matrix(AECM) and to analyze its component. METHODS: With low-osmosis theory and method of cell extraction by detergent, bone acellular extra-cell matrix was prepared. We observed morphologic changes with HE, Mallory-Heidenhain rapid one-step dyeing and Alcian blue dyeing and examined fibronectin(FN) and laminin(LN) with immunohistochemistry. RESULTS: Light microscope showed that the collagen fibers arranged regularly in AECM with blankness of bone lacunas by HE, Mallory-Heidenhain rapid one-step dyeing and that the region around bone lacunas was stained different degrees of blue-green by Alcian blue dyeing. The result of immunohistochemistry showed there are positive markers of FN and LN in ECM. CONCLUSION: This method for preparation of bone acellular extra-cell matrix is effective, and it can keep natural structure of collagen fibers and maintain components of ECM, such as proteoglycan, FN and LN.