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OBJECTIVE: Studies have shown that the levels of pleiotrophin (PTN) are greatly elevated in the synovial fluid and cartilage in osteoarthritis. Therefore, the purpose of this study was to investigate the effect and mechanism of PTN on the chondrogenic differentiation of DPSCs in inflammatory and normal microenvironments. MATERIALS AND METHODS: A lentiviral vector was used to deplete or overexpress PTN in DPSCs. The inflammatory microenvironment was simulated in vitro by the addition of IL-1ß to the culture medium. The chondrogenic differentiation potential was assessed using Alcian Blue staining and the main chondrogenic markers. A dual-luciferase reporter assay was used to explore the relationship between miR-137 and PTN. RESULTS: The results showed that 0.1 ng/mL IL-1ß treatment during chondrogenic induction greatly impaired the chondrogenic differentiation of DPSCs. Supplementation with PTN and PTN overexpression inhibited chondrogenic differentiation of DPSCs, while PTN depletion promoted chondrogenic differentiation. MiR-137 negatively regulated the expression of PTN by binding to the 3'UTR of its mRNA. Moreover, miR-137 promoted chondrogenic differentiation of DPSCs in normal and inflammatory microenvironments. CONCLUSION: Our results suggest that PTN may play an inhibitory role in the chondrogenic differentiation of DPSCs in normal and inflammatory microenvironments, which is regulated by miR-137.
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Osteoarthritis is a chronic degenerative joint disease that exerts significant impacts on personal life quality, and cartilage tissue engineering is a practical treatment in clinical. Various growth factors are involved in cartilage regeneration and play important roles therein, which is the focus of current cartilage repair strategy. To compensate for the purification difficulty, high cost, poor metabolic stability, and circulating dilution of natural growth factors, the concept of functional motifs (also known as mimetic peptides) from original growth factor was introduced in recent studies. Here, we reviewed the selection mechanisms, biological functions, carrier scaffolds, and modification methods of growth factor-related functional motifs, and evaluated the repair performance in cartilage tissue engineering. Finally, the prospects of functional motifs in researches and clinical application were discussed.
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OBJECTIVE: To explore the correlation between the anterior border absorption of the mandibular ramus and the occurrence of supernumerary teeth, along with the biomechanical stress. DESIGN: The bone mass of mandibular ramus was evaluated on CBCT images by bone mass analysis. In addition, the number of supernumerary teeth and corresponding anatomical positions were recorded. RESULTS: The CBCT images of 5100 patients were analyzed. Along with eruption of mandibular permanent molars in sequence, the width of the ramus increased from 29.02 mm to 36.02 mm (P < 0.001). The proportion of the width from the nerve canal to the anterior border of the ramus in the whole ramus decreased from 52.51% to 43.79% (P < 0.001). Meanwhile, among the 5100 participants, 278 supernumerary teeth were identified in 209 patients (4.1%). The predilection loci were close to the regions of central incisors (72.66%) in the maxilla and of the premolars (11.51%) in the mandible. CONCLUSIONS: Biomechanical stress, mainly pressure during tooth development, was the internal force of anterior border absorption of the mandibular ramus. The release of pressure after tooth eruption is a possible reason for the occurrence of supernumerary teeth.