In recent years, the field of cartilage tissue engineering has seen a sharp increase in publications using many tissue engineering techniques and various analysis methods. Comparison between studies remains difficult, due to a lack of uniformity in methods used. A broad range of histological scoring systems is used to examine cartilage quality. Unfortunately, so far little is known on the reliability and correlation of these scoring systems. The objective of this study was to compare two frequently used cartilage repair grading scales, namely, the comprehensive O'Driscoll and the simple Pineda scale. We determined the intra- and interobserver variability of each score as well as the correlation between them. Thirty-eight joint section samples with variable cartilage quality were examined. Three observers documented their findings with both systems at two points in time. Statistical analysis showed very good intra- and interobserver reliability as well as a good correlation between the two scores. For the intraobserver variability of the O'Driscoll scale, we found an average difference of 0.05 with a SD of 0.93 in a 24-point score and a kappavalue of 0.87. For the interobserver reliability, the average difference was 0.001, SD 2.25, and a kappavalue of 0.92. The Pineda scale showed an average difference of 0.86 with a SD of 1.38 in a 14-point score and a kappavalue of 0.86 for the intraobserver reliability, whereas values for the interobserver reliability were average difference 0.82, SD 0.96, and a kappavalue of 0.89. The comparison between the two scales showed a high, inversely related correlation with a correlation coefficient of 0.71. From these results, we concluded that both the O'Driscoll and the Pineda scales are reliable semiquantitative cartilage scoring systems and that acceptance for general use of these two scores will benefit the reliability of literature on tissue engineering for cartilage repair. Thus, the added strength of comparison between published study results allows better understanding of cartilage repair publications and increases the impact of their results.
Odontogenesis is a complex process with a series of epithelial-mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet-rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC-fibrin glue-PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein-1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue-PRF could regenerate a complete tooth.
Intra-articular injection of hyaluronic acid (HA) has been widely accepted for the treatment of osteoarthritis (OA) in early stage. l-Glutathione (GSH), an antioxidant, has an anti-inflammatory effect on protecting cells from reactive oxygen species and reactive nitrogen species (ROS/RNS). In this study, the therapeutic effects of HA (0.1%) supplemented with GSH (0, 5, 10, and 20% in weight ratios to HA) on human fibroblast-like synoviocytes (FLSs) were evaluated. The results showed that cell morphology and glycosaminoglycan production of FLSs were not changed under treatments. However, the addition of HA + 20% GSH significantly decreased cell survival (p < 0.001) relative to other groups. Relative to un-stimulated FLSs, interleukin-1 beta (IL-1β) stimulation significantly decreased the total antioxidant capacity (p < 0.001) of cells. The antioxidant capacity was restored and the intracellular ROS/RNS was decreased in HA or HA + GSH-treated FLSs. Real-time PCR analysis revealed the mRNA levels of IL-1β, tumor necrosis factor-alpha, and matrix metalloproteinase-3 were down-regulated significantly (all p < 0.05) when FLSs cultured in HA or HA + GSH. IL-6 mRNA expressions were down-regulated significantly in HA and HA + 5% GSH groups (both p < 0.05) but up-regulated when HA supplemented with 10% and 20% GSH (both p < 0.01). In addition, the protein levels of IL-1β were further decreased with significant differences (both p < 0.05) in the HA + 10% GSH and HA + 20% GSH groups when compared to FLSs cultured in normal medium. In conclusion, HA supplemented with GSH improves antioxidant capacity and modulates pro-inflammatory cytokines expressions in FLSs. GSH has the potential to augment the effect of viscosupplementation using HA on OA patients. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2071-2079, 2016.
Islet preservation plays an important role for the success of islet transplantation. To determine the optimal method for islet preservation, we compared the outcomes of islet culture, cold preservation, and cryopreservation in this study. Isolated rat islets were divided into three groups: 37 °C group (conventional culture at 37 °C in RPMI-1640 medium), 4 °C group (cold preservation at 4 °C in University of Wisconsin (UW) solution), and -80 °C group (cryopreservation at -80 °C with dimethyl sulfoxide (DMSO)). Recovery rate, Calcein-AM/PI double staining, insulin release, mRNA level of hypoxia-inducible factor-1α (HIF-1α), and protein level of Bax in islets were examined after short-term (1 day) or long-term (7 days) preservation. After either short-term or long-term preservation, 4 °C group showed higher recovery rate of the islets number, lower percentage of PI positive area, better insulin release ability, and lower expression levels of HIF-1α and Bax in comparison to the 37 or -80 °C group. Meanwhile, islets in 37 °C group showed better function, and down-regulation of HIF-1α and Bax than those in -80 °C group on day 1; however, worse function of islets, up-regulated HIF-1α and Bax in 37 °C group were observed in comparison to -80 °C group on day 7. These results suggest that cold preservation at 4 °C in UW solution is the optimal method in comparison to the conventional culture at 37 °C or cryopreservation at -80 °C for short-term or long-term islet preservation. Furthermore, the potential mechanism may relate to, at least in part, apoptosis induced by the HIF-1α.
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