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BACKGROUND:The degradable poly-L-lactic acid (PLLA) biliary-enteric composite stent has been developed. OBJECTIVE:To analyze the solubility and biocompatibility of the degradable PLLA biliary-enteric composite stent. METHODS:Solubility:the PLLA composite stent was implanted into artificial gastric acid to detect the dissolution rate within 12 weeks. Pyrogen test:the PLLA composite stent extracts were injected into the rabbits via ear vein to detect the changes of body temperature. Hemolysis test:the PLLA composite stent extracts, normal saline and distil ed water were added into the rabbit anticoagulant, respectively, to detect the hemolysis ratio. Cytocompatibility test:Caco-2 cel s were respectively cultured in the DMEM medium containing 10%fetal bovine serum, rubber material extracts and the PLLA composite stent extracts, and the cel proliferation was detected at 12, 24, 36 and 48 hours;the lactic dehydrogenase release was detected at 2 days. RESULTS AND CONCLUSION:The PLLA composite stent showed a long stability in vivo, and approximately 80%was dissolved at about 20 weeks. No reactions of pyrogen and henolysis were observed in the pyrogen and hemolysis tests. The PLLA composite stent made no effects on the Caco-2 cel proliferation and lactic dehydrogenase release. In conclusion, the PLLA composite material holds a good solubility and cytocompatibility.
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BACKGROUND: With good biocompatibility, osteoconduction and biodegradability, calcium phosphate ceramics is considered as a substitute of autologous bone; furthermore, it also has the potentiel of osteoinduction after structure optimization. OBJECTIVE: To review the physicochemical properties of calcium phosphate ceramic and its osteoinduction. METHODS: A computer-based search of databases such as PubMed, Springer, ResearchGate and Baidu Academic was performed for articles relevant to calcium phosphate ceramics published from January 2000 to October 2015. And the keywords were “calcium phosphate, osteoinduction, tissue engineering, scaffolds” in English. RESULTS AND CONCLUSION: To date, there are four ideal kinds of calcium phosphate materials including hydroxyapatite, tricalcium phosphate, amorphous calcium phosphate and hydroxyapatite/tricalcium phosphate biphasic ceramic material. Hydroxyapatite has better strength and cel adsorption capacity, but has poor biodegradation. Tricalcium phosphate has good abilities of osteogenesis and degradation, but its degradation rate is hard to match the new bone formation,and its strength is also relatively poor. Amorphous calcium phosphate has neither strength nor solubility. In contrast, biphasic calcium phosphate ceramics has moderate degradation rate between hydroxyapatite and tricalcium phosphate, and therefore, it either can be replaced by autologous bone after degradation or exhibits proper strength. While how to further improve the physical properties and promote osteogenesis stil need much deeper research.
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BACKGROUND:The phenomenon of osteoinduction by biomaterials has been proven in animal experiments. OBJECTIVE:To investigate whether the ability of a biomaterial to initiate bone formation in ectopic implantation sites improves the performance of osteoinductive biomaterial as a scaffold for tissue-engineered bone. METHODS:We compared ectopic bone formation by combining autologous adipose-derived stromal cells with an osteoinductive and a nonosteoinductive biphasic calcium phosphate ceramic to create a tissue engineering construction in the muscle of dogs. Al implants were implanted in the back muscle of 10 adult dogs for 8 weeks and 12 weeks, including osteoinductive biphasic calcium phosphate ceramic+adipose-derived stromal cells (osteoinductive complex group), osteoinductive biphasic calcium phosphate ceramic (osteoinductive broup), nonosteoinductive biphasic calcium phosphate ceramic+adipose-derived stromal cells (nonosteoinductive complex group), and nonosteoinductive biphasic calcium phosphate ceramic (nonosteoinductive group). Micro-CT analysis and histomorphometry were performed to evaluate and quantify ectopic bone formation. RESULTS AND CONCLUSION:Ectopic bone formation was visible in the osteoinductive complex group and osteoinductive group, and the former group was superior to the latter one in quality of new bone (P<0.05). However, there was no ectopic bone formation in the other two groups. Micro-CT results were consistent with the histomorphological detection. These findings indicate that osteoinductive biphasic calcium phosphate ceramic, as a kind of bone tissue engineering scaffold material, has a better osteogenic capacity, while adipose-derived mesenchymal stem cells serve as seed cells to promote the ectopic bone formation.
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Objective To investigate the expression of TLR2 in colon mucosa of ulcerative colitis (UC) and to analyze the correlation with clinical activity and endoscopic grading. Methods The biopsies from 47 UC patients and 13 healthy controls were collected, and the expression of TLR2 protein and mRNA in colonic mucosa was determined by Western Blot and semi-quantitative RT-PCR, respectively. The patients were graded according to endoscopic and clinical findings. Results The expressions of TLR2 protein and TLR2 mRNA in UC patients were significantly increased than those in healthy controls, which was correlated with the progression of the disease. Conclusion The expressions of TLR2 protein and TLR2 mRNA in colon mucosa from UC patients might be used as a marker for disease activity.