ABSTRACT
BACKGROUND: Human amniotic mesenchymal stem cells (hAMSCs) are adult stem cells with multipotential differentiation, which can be induced to differentiate into bone, cartilage and other connective tissues. Meanwhile, as a highly specific marker of tenocytes, Scleraxis is involved in aggregation and differentiation of tendon progenitor cells as well as the formation of tendon extracellular matrix. OBJECTIVE: To investigate whether hAMSCs have the ability of differentiation into tenocytes by ectopic expression of Scleraxis. METHODS: Agreed by puerpera, the amniotic membrane from the full-term placenta was separated, and hAMSCs were isolated by a two-step enzyme digestion, observed under inverted phase contrast microscope, and identified by flow cytometry. Passage 3 cells were induced via plasmid-mediated Scleraxis overexpression in overexpression group. Untransfected cells cultured in normal medium served as blank control group, and those with empty plasmid transfection were defined as empty plasmid group. Cell proliferation was tested in each group using cell counting kit-8 within 7 days of culture. Real-time quantitative PCR and western blot were used to assess the tenogenic differentiation of hAMSCs in each group at 3 and 7 days of culture. RESULTS AND CONCLUSION: Findings from the cell counting kit-8 indicated that the cell viability had no significant differences among the groups within 7 days of culture (P > 0.05). Western blot results showed the protein expression of Scleraxis in the treatment group was significantly higher than that in the other two groups (P < 0.05). Real-time PCR results showed, at 3 days of culture, the expression of collagen type I, collagen type III, Fibronectin and Tenascin-C in the overexpression group was significantly higher than that in the empty plasmid group (P < 0.05), but the expression of Tenomodulin had no difference (P > 0.05); at 7 days of culture, the expressions of collagen type I, collagen type III, Fibronectin, Tenascin-C and Tenomodulin in the overexpression group were significantly higher than those in the empty plasmid group (P < 0.05). In summary, hAMSCs can be differentiated into tenocytes by ectopic expression of Scleraxis.
ABSTRACT
OBJECTIVE: To investigate the association between the pathological features of carotid plaque and ipsilateral symptoms of cerebral ischemia. MATERIALS AND METHODS: We sought to identify clinical observational studies comparing the incidence of pathological features between symptomatic and asymptomatic carotid plaques in terms of ulceration, thrombosis and intraplaque hemorrhage (IPH), published between 1996 and 2006. A search on, PubMed was supplemented by a review of bibliographies of relevant articles and lists of references in it. Odds ratios (OR) for the presence of each feature as a role in the pathogenesis of neurological events were calculated and combined by a meta-analysis. RESULTS: We integrated 16 clinical studies totaling 2839 plaques harvested at endarterectomy procedures. The reported incidence for each feature was highly variable. The methods in defining ulceration, thrombosis and IPH were very heterogeneous. The time intervals between the latest onset of ischemic symptoms and pathological examinations varied greatly. Overall, the incidence of ulcerated plaques in the symptomatic group were significantly higher than that in the asymptomatic group (study number, n=10; OR, 2.32; 95% CI, 1.90-2.83. A random-effect model was performed among studies regarding surface thrombosis because an apparent trend for heterogeneity was observed (n=6; OR, 1.57; 95% CI, 0.68-3.64). There was no difference with respect to IPH between the two groups (n=11; OR, 1.09; 95% CI, 0.91-1.32). CONCLUSIONS: Ulcerated carotid plaque is significantly correlated with the production of neurological events, whereas thrombosis fails to correlate with ischemic symptoms because of the presence of substantial heterogeneity. The association between IPH and clinical presentations is less clear.