Comparison of fracture site callus with iliac crest bone marrow as the source of plastic-adherent cells.

Background: Red marrow has been described as the main source of mesenchymal stem cells although its aspiration and isolation from bone marrow was reported to have significant donor site morbidity. Since secondary bone healing occurs through formation of callus as the result of proliferation and differentiation of mesenchymal stem cells, callus may become alternative source for mesenchymal stem cells. In this study, we compared the number of plastic-adherent cells from fracture site callus and bone marrow of iliac crest after two and four weeks of culture. Methods: Sixteen New Zealand rabbits were fracturized at the femoral shaft. Then, these rabbits were taken care. After two weeks of fracturization, 3 mL iliac crest bone marrow aspiration and callus extraction of eight rabbits were cultured (group I). The other eight rabbits were treated equally after four weeks of fracturization (group II). Simultaneously, the cultures were observed after one and two weeks. Four weeks later, they were harvested. Cells were counted using Neubauer hemocytometer. The average number of cells between the sources and groups were statistically analyzed using the unpaired t-test. Results: In group I, there were 2.6 ± 0.1 x 104 cells in the culture of iliac crest bone marrow aspirate and 2.5 ± 0.1 x 104 cells in culture of callus extract from fracture site (p = 0.34). In group II, there were 2.7 ± 0.1 x 104 cells and 2.1 ± 0.1 x 104 cells, respectively (p < 0.001). Conclusion: Fracture site callus at the second week post-fracturization may be potential as source of plastic-adherent cells compared with iliac crest bone marrow.

Iliac crest and femoral bone marrow as the source of plastic-adherent cells.

Background: Many studies have used iliac crest as the source of mesenchymal stem cells. In cases of long bone shaft fracture, obtaining marrow from the fracture site offers more advantages. Nevertheless, due to the high number of fat cells in long bones, the yellow marrow of long bones is believed to contain lower number of mesenchymal stem cells than red marrow. Therefore the aim of this study is to compare the potency between red and yellow marrow as the donor site for the isolation of mesenchymal stem cell. Methods: Bone marrow of eight giant Flemish rabbits was aspirated from the iliac crest and femoral shaft. Mononuclear cells were isolated from both aspirates and expanded in low glucose DMEM. After eight weeks, the cells were harvested and counted using improved Neubauer hemocytometer. Comparison of the cell number between the two donor sites was then performed by t-test. Results: After 8 weeks, an average number of 2.93 ± 0.91 x 104 and 3.7 ± 2.50 x 104 cells were obtained from the iliac and femoral group respectively. No statistically significant difference was found between those two groups (p = 0.45). Conclusion: Plastic-adherent cells can be isolated and expanded from both iliac crest and femoral shaft.