Hyper-expression of Osteocalcin mRNA in Odontoblasts of Hyp Mice

The Hyp mouse is a murine homologue of human X-linked hypophosphatemia that displays hypo-mineralization in bone and dentin. In this study, we tested the hypothesis that the defect in Hyp mice leads to alterations in the expression of dentin matrix proteins that may be associated with the hypo-mineralization changes in the tissues. Quantitative RT-PCR analyses showed that expression of the osteocalcin gene in Hyp mice tooth germ samples was significantly higher than in wild-type mice, whereas the gene expressions of osteonectin, osteopontn, dentin matrix protein 1, and type I collagen in both types of mice were similar. Further, cultured Hyp mice tooth germ samples exhibited a higher expression of the osteocalcin gene than did those from wild-type mice, which was in accord with the results of our in vivo analysis. These findings suggest that osteocalcin mRNA is highly expressed in Hyp mice odontoblasts and may be associated with dentin hypo-mineralization.

Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure

Objectives

To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone.

Methods

Osteogenic cell sheets were prepared by culturing rat bone marrow stromal cells in a minimal essential medium (MEM), MEM with AscP, MEM with Dex, and MEM with Dex and AscP (Dex/AscP). The cell number and messenger (m)RNA expression were assessed in vitro, and the appearance of the cell sheets was observed after mechanical retrieval using a scraper. β-tricalcium phosphate (β-TCP) was then wrapped with the cell sheets from the four different groups and subcutaneously implanted into rats.

Results

After mechanical retrieval, the osteogenic cell sheets from the MEM, MEM with AscP, and MEM with Dex groups appeared to be fragmented or incomplete structures. The cell sheets cultured with Dex/AscP remained intact after mechanical retrieval, without any identifiable tears. Culture with Dex/AscP increased the mRNA and protein expression of extracellular matrix proteins and cell number compared with those of the other three groups. More bridging bone formation was observed after transplantation of the β-TCP scaffold wrapped with cell sheets cultured with Dex/AscP, than in the other groups.

Conclusions

These results suggest that culture with Dex/AscP improves the mechanical integrity of the osteogenic cell sheets, allowing retrieval of the confluent cells in a single cell sheet structure. This method may be beneficial when applied in cases of difficult tissue reconstruction, such as nonunion, bone defects, and osteonecrosis.

Cite this article: M. Akahane, T. Shimizu, T. Kira, T. Onishi, Y. Uchihara, T. Imamura, Y. Tanaka. Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure. Bone Joint Res 2016;5:569–576. DOI: 10.1302/2046-3758.511.BJR-2016-0013.R1.

Metachronous solitary metastasis of renal cell carcinoma to the contralateral adrenal gland after nephrectomy

Background. Metachronous solitary metastasis of renal cell carcinoma (RCC) to the contralateral adrenal gland is very rare. We assessed the clinocopathological findings of such patients who received adrenalectomy. Methods. We retrospectively reviewed the records of all 495 patients who underwent nephrectomy for RCC; excluding those in stage IV, between 1980 and 1993. Of these patients, 5 who showed metachronous solitary metastasis to the contralateral adrenal gland, and also received adrenalectomy were the subjects of this study. Results. The adrenal metastasis was found between 14 and 132 months (median, 81 months) after nephrectomy. After the solitary adrenalectomy, patient survival ranged from 450 to 2160 days (median, 660 days); 2 patients were alive with no evidence of disease at 660 and 1830 days, respectively, and 3 patients died of this disease, at 450, 480, and 2160 days, respectively, after adrenalectomy. The overall survival rate was 100% at 5 years, 80% at 6 years, 60% at 7 years, and 40% thereafter. The 2 patients with no evidence of disease did not receive steroid supplementation, because they had not received ipsilateral adrenalectomy. No significant difference was observed between survivors and non-survivors in terms of clinicopathological factors such as affected side, location of the tumor, tumor size of primary/metastatic lesion, and stage or grade of primary/metastatic lesion. From the viewpoint of outcome, patients with early recurrence tended to show an unfavorable prognosis compared with prognosis in those with late recurrence. Conclusion. The prediction of outcome in patients with RCC who undergo, adrenalectomy for metachronous solitary metastasis to the contralateral adrenal gland is difficult. Although the factors that affect prognosis are uncertain, long-term observation for unusual metachronous metastasis to the contralateral adrenal gland is mandatory in patients with RCC.