Consideration of bone regeneration effect of stem cells: comparison between adipose-derived stem cells and demineralized bone matrix.

BACKGROUND: Currently, many studies have sought to address the regeneration of extensive bone defects using stem cells. Here, the authors injected adipose-derived stem cells and demineralized bone matrix (DBM) into areas of bone defect in rabbits and compared their effect on bone regeneration to study the clinical usefulness of stem cells. METHODS: This study used 20 male New Zealand white rabbits. Four craniectomies were made in 20 male New Zealand white rabbits' calvaria, and 4 different groups of experimental conditions were applied to each of the 4 cranial defects. To the first group, 0.2 mL of DBX, a commercially available clinical preparation ofDBM, was applied with fibrin glue. To the second group, 0.2 mL of adipose-derived stem cells, with confirmed bone differentiation ability, was applied with fibrin glue. To the third group, 0.1 mL of DBX, 0.1 mL of adipose-derived stem cells, and fibrin glue were applied. The fourth group of defects acted as the control and was left unaltered. After 6 weeks, regenerated bone from each defect site in each rabbit was collected and measured for volume change. Bone regeneration was assessed with three-dimensional skull bone computed tomography and histological analysis. RESULTS: Osteoblasts were confirmed in all defect groups after 6 weeks. Overall, bone regeneration was weakest in the control group, whereas other groups of defects showed distinct bone regeneration. In particular, group 3, to which adipose-derived stem cells and DBM were applied, demonstrated the most active regeneration. CONCLUSIONS: Both adipose-derived stem cells and DBM demonstrated regeneration effect on cranial defects in rabbits, but it is difficult to conclude which was better, because in each case the amount of regenerated bone was within the margin of error. However, as the most active bone regeneration was observed when both adipose-derived stem cells and DBM were applied together, this combination could be helpful in the correction of extensive bone defects.

Consideration of bone regeneration effect of stem cells: comparison of bone regeneration between bone marrow stem cells and adipose-derived stem cells.

BACKGROUND: Much controversy exists as to how stem cells efficiently differentiate and regenerate. To research how stem cell origin affects optimal differentiation and regeneration, the authors collected stem cells from bone marrow and fat and compared amounts of bone regeneration from both groups of cells. METHODS: This study used 16 New Zealand white rabbits raised in similar surroundings and conditions. After collecting stem cells from bone marrow and fat, osteoblast generation was induced. In each rabbit, 2 craniectomies (10 × 10 mm) were made into each rabbit's calvarium, and 0.2 mL (1 × 10(6) cells/mL) of bone marrow-derived and adipose-derived stem cells were transplanted into each defect. After 3 and 5 weeks of transplantation, computed tomography was conducted. After 6 weeks, regenerated bone tissue was collected and measured for volume, and biopsy was performed. RESULTS: Both bone marrow- and adipose-derived stem cells were effective in bone regeneration of the defect. Bone marrow stem cells demonstrated greater differentiation into osteoblasts, but there was no difference in the amount of measured regenerated bone volume after 6 weeks. CONCLUSIONS: Adipose-derived stem cells differentiate directly into osteoblasts less often than do bone marrow-derived stem cells. However, the total amount of regenerated bone is almost the same because of the effect of indirect bone regeneration. As adipose-derived stem cells are easily accessible and have the potential to abundantly proliferate into mesenchymal cells, they could be an effective bone regeneration material.

Survival outcomes of different treatment methods for the ipsilateral breast of occult breast cancer patients with axillary lymph node metastasis: a single center experience.

PURPOSE: This study compared the survival outcomes of different treatment methods for the ipsilateral breast of occult breast cancer (OBC) patients with axillary lymph node metastasis. METHODS: A retrospective study was conducted in which forty OBC patients with axillary lymph node metastasis were identified out of 15,029 patients who had been diagnosed with a primary breast cancer at between 1992 and 2010. The patients were categorized into three treatment groups based on ipsilateral breast management: breast-conserving surgery (BCS) (n=17), mastectomy (n=12), and nonsurgical intervention with or without radiation therapy (No surgery with or without radiation therapy [No Op±RT]) (n=11). All patients underwent axillary lymph node dissection. Cases were evaluated based on treatment and potential prognostic factors with respect to overall survival (OS) and disease-free survival (DFS). RESULTS: During the follow-up period (median follow-up of 71.5 months), the overall OS and DFS were 76.9% and 74.9%, respectively. The 5-year treatment-specific OS was 72.0% for the BCS group, 74.0% for the mastectomy group, and 87.5% for the No Op±RT group (log-rank p=0.49). The 5-year DFS was 70.6% for the BCS group, 66.7% for the mastectomy group, and 90.9% for the No Op±RT group (log-rank p=0.36). Recurrence rates for the BCS and No Op±RT groups were 5.9% and 18.2%, respectively. Histologic grade and lymph node status were inversely correlated with DFS (log-rank p=0.04 and p<0.01, respectively). CONCLUSION: There was no difference in survival outcomes between the three treatment methods for the ipsilateral breast (mastectomy, BCS, and No Op±RT) of OBC patients with axillary lymph node metastasis. A large-scale multicenter study is needed to validate the results from this small retrospective study.