Presence of Cartilage Stem/Progenitor Cells in Adult Mice Auricular Perichondrium

BACKGROUND: Based on evidence from several other tissues, cartilage stem/progenitor cells in the auricular cartilage presumably contribute to tissue development or homeostasis of the auricle. However, no definitive studies have identified or characterized a stem/progenitor population in mice auricle. METHODOLOGY/PRINCIPAL FINDINGS: The 5-bromo-2'-deoxyuridine (BrdU) label-retaining technique was used to label dividing cells in fetal mice. Observations one year following the labeling revealed that label-retaining cells (LRCs) were present specifically in auricular perichondrium at a rate of 0.08±0.06%, but LRCs were not present in chondrium. Furthermore, LRCs were successfully isolated and cultivated from auricular cartilage. Immunocytochemical analyses showed that LRCs express CD44 and integrin-α(5). These LRCs, putative stem/progenitor cells, possess clonogenicity and chondrogenic capability in vitro. CONCLUSIONS/SIGNIFICANCE: We have identified a population of putative cartilage stem/progenitor cells in the auricular perichondrium of mice. Further characterization and utilization of the cell population should improve our understanding of basic cartilage biology and lead to advances in cartilage tissue engineering and novel therapeutic strategies for patients with craniofacial defects, including long-term tissue restoration

Nasopalatine duct cyst associated with dental implant treatment: A case report

AbstractMaxillary anterior implants are associated with the risk of nasopalatine canal damage. Here we present the case of a 37-year-old man who developed a nasopalatine duct cyst after maxillary implant placement. The patient received an implant 3 months after the extraction of a fractured maxillary right central incisor. At a maintenance visit 9 years after the procedure, he complained of swelling and mild pain in the palatal region of the implant. A panoramic radiograph and computed tomography (CT) scan revealed a large, well-circumscribed, periapical radiolucency surrounding the apical portion of the implant and extending to the nasopalatine duct. We removed the entire lesion without removing the implant. Histopathologic examination of the resected specimen revealed a nasopalatine duct cyst. Accidental contact with the nasopalatine canal during implant surgery may have led to the development of the nasopalatine duct cyst. Careful planning using a preoperative CT scan prior to implant placement may prevent such complications

The Role of Sonic Hedgehog Signaling in Osteoclastogenesis and Jaw Bone Destruction.

Sonic hedgehog (SHH) and its signaling have been identified in several human cancers, and increased levels of its expression appear to correlate with disease progression and metastasis. However, the role of SHH in bone destruction associated with oral squamous cell carcinomas is still unclear. In this study we analyzed SHH expression and the role played by SHH signaling in gingival carcinoma-induced jawbone destruction. From an analysis of surgically resected lower gingival squamous cell carcinoma mandible samples, we found that SHH was highly expressed in tumor cells that had invaded the bone matrix. On the other hand, the hedgehog receptor Patched and the signaling molecule Gli-2 were highly expressed in the osteoclasts and the progenitor cells. SHH stimulated osteoclast formation and pit formation in the presence of the receptor activator for nuclear factor-κB ligand (RANKL) in CD11b+ mouse bone marrow cells. SHH upregulated phosphorylation of ERK1/2 and p38 MAPK, NFATc1, tartrate-resistant acid phosphatase (TRAP), and Cathepsin K expression in RAW264.7 cells. Our results suggest that tumor-derived SHH stimulated the osteoclast formation and bone resorption in the tumor jawbone microenvironment

A case of adenoid cystic carcinoma associated with IgG4-related disease

Introduction: Immunoglobulin G4-related disease (IgG4-RD) is an inflammatory condition associated with elevated serum IgG4 levels and tissue infiltration by IgG4-expressing plasma cells. We present a case of adenoid cystic carcinoma (ACC) of the submandibular gland with possible involvement of IgG4-RD. Presentation of case: The patient was a 59-year-old man presenting with a swollen right submandibular gland. Laboratory tests revealed IgG4 levels of 176 mg/dl (reference range: 4.8–105). An initial open biopsy for histological diagnosis showed chronic sialadenitis. The region was monitored on an outpatient basis, and finally the right submandibular was totally resected because malignant tumor could not be excluded. Histological examination of the submandibular gland showed an ACC with lymphocytic infiltration containing many IgG4-positive plasma cells in the tumor stroma. Discussion: We have described a case that indicated a possible involvement of ACC with IgG4-RD. This allows us to speculate that longstanding IgG4-RD may progress to malignancy or infiltration of IgG4-positive plasma cells through the signals of tumor stimuli. Further investigations are required to determine the potential pathogenic mechanism underlying this unique tumor. Conclusion: This case underscores that caution is needed in the diagnosis of masses with high serum IgG4 levels, as the differential diagnosis includes malignancy

Effects of SHH on MAP kinase activity and osteoclast differentiation.

<p>(<b>A</b>) Detection of p-ERK, ERK, p-p38, and p38 by immunoblot analysis after RANKL (50 ng/ml) in murine macrophage RAW264.7 cells with or without SHH (500 ng/ml). (<b>B</b>) Immunoblot analysis of NFATc1 in RAW264.7 cells 0–48 h after RANKL (30 ng/ml) or SHH (500 ng/ml) treatment. (<b>C</b>) The mature osteoclast-differentiated cells were treated with SHH (500 ng/ml) or RANKL (30 ng/ml). Protein expression of TRAP and Cathepsin K was analyzed by immunoblot analysis. Similar results were obtained in three different experiments.</p

Immunohistochemical staining for Sonic hedgehog (SHH), Patched, CD68 and Gli-2 in normal epithelium and osteolytic mandibular squamous cell carcinoma.

<p>(A) SHH, Patched, CD68 and Gli-2 expression in the normal epithelium at the edges of area were the mandible was resected. Each right photo is a magnification of the rectangle delimited area of normal epithelium in the corresponding left photo. Scale bar, 50 μm. (B) SHH, Patched, CD68 and Gli-2 expression in a resected mandible. Scale bar, 50 μm. Arrow: osteoclast. Arrowhead: osteoclasts progenitor cell.</p

Hedgehog stimulated osteoclast formation of RAW264.7 cells, CD11b⁺ cells in bone marrow, and bone marrow macrophages.

<p>(<b>A</b>) RAW264.7 cells were inoculated onto a 96-well plate at different cell densities and then treated with increasing concentrations of RANKL +/- SHH for 6 days. Osteoclast formation was evaluated by TRAP staining. (<b>B and C</b>) CD11b⁺ cells isolated from the bone marrow of 5-week-old mice were cultured in the presence of 30 ng/ml M-CSF and 50 ng/ml RANKL with or without 500 ng/ml SHH in 96-well plate for 6 days. Cultures were also treated with or without SHH and hedgehog inhibitor cyclopamine for 6 days (C). Bone marrow macrophages were cultured with indicated amount of SHH in the presence of 30 ng/ml M-CSF and 50 ng/ml RANKL in 48-well plate for 7 days. TRAP-positive multinucleated cells (nuclear number > 3) were counted as osteoclasts. The data from a typical experiment are presented. Data are shown as the mean ± SD. Statistically significant differences (*P < 0.05, **P < 0.01) between the indicated groups are marked by asterisks.</p