Fig. 4. Differences between normal and abnormal colonies taken from the same patient’s sample.

A. Five accepted markers of BMSCs were used in FACS analysis to compare the abnormal (left column) and normal (right column) cells (red) from patients with SM to healthy donor BMSCs (blue). Green denotes the unstained control. The mean fluorescent intensity of CD105 appeared higher in the patients’ samples, while they are lower for CD146. For details of antibodies used see Methods. B. Using osteogenic and adipogenic tissue culture media we demonstrated that the abnormal colonies are not able to form a calcified matrix (as shown by Alizarin red staining that labels calcium), but seem to produce more fat cells (as shown by Oil red staining). C. Illustration of the technique of studying engraftment of human CD34⁺ hematopoietic progenitors in immune-compromised NSG mice. Following co-culturing the CD34⁺ cells with BMSCs derived from healthy donors, or normal and abnormal colonies from patients, the CD34⁺ cells are injected into NSG mice previously treated with busulphan; and 4 weeks later, engraftment is determined by the percentage of human CD45⁺ cells in the peripheral blood. D. shows that BMSCs from healthy donors better support CD34⁺ progenitors to form more blood cells than those derived from normal and abnormal cells from patients. Five mice were used in each group. Statistical significance is labeled as * = p<0.05 and ** = p<0.05