The Characterizes Of The Osteoblast-like Cells Derived From Human Bone Marrow Mesenchymal Stem Cell And Hematopoietic Stem Cell

Objectives: 1 Human marrow mesenchymal stem cells (MSC) have multipotential ability and can differentiate into osteoblasts in vitro. To compare the biological characteristics of the MSC-derived osteoblast-like cells under different induce time period and the normal adult osteoblasts isolated from iliac trabecular. 2 To investigate if the hematopoietic cell marker, CD34, is also present on osteoblast progenitor cells and studied the interactions of hematopoietic and osteogentic stem cells in marrow. Methods: 1 MSC were separated from human marrow with Ficoll reagent and expanded in culture medium in vitro. To detect the surface antigens, the labeled cells were analysed on fluorescence-activated cell sorting (FASC), MSC were induced to differentiate into osteoblasts with dexamethasone (DEX), ascrobic acid, p-glycerophosphate (named OS medium). Cell morphology, alkaline phosphatase (ALP), type I collagen, osteocalcin (OCN) were detected. Effects of bone morphogenetic protein-2 (BMP-2) and DEX with different concentrations on these MSC-derived osteoblast-like cells after 7 and 14 days were observed and the results were compared with those obtained from the osteoblasts isolated from iliac trabecular. 2 Marrow cell isolated by Mini MACS system on the basis of CD34 antigen expression and detected the purity of CD34+ population by FACS, these CD34+ cells were cultured in OS medium and the properties of osteoblastic differentiation were detected. Results: 1 The expanded adherent MSC were positive for CD29, CD105, Stro-1 and negative for CD34. After osteoblasts induction, the cells changed from spindle-shape to cuboidal and polygonal in cell morphology. The ALP, type I collagen, OCN expression were positive. In vitro, cells of osteoblastic differentiation after 14 days had more mature characteristics than those after 7 days, but osteogenic3activity was weak when compared with the osteoblasts isolated from iliac trabecular. 2 The average purity of CD34+ cells isolated from bone marrow mononuclear cells could be as high as 95%. CD34+ cells could grow in the serum-containing medium directly and obtained adherent cells, but they had low expand potiential. CD34+ cells induced differentiation into osteoblasts after 7 days expressed osteoblastic markers: ALP, OCN, type I collagen, and the calcium deposition could be detected by vonKossa staining. Conclusions: 1 The osteoblast-like cells derived from MSC had distinct cell mature degree at culture by 7 days and 14 days in differentiation process. 2 The osteogenic activity of osteoblasts from iliac trabecular was stronger than that of the osteoblasts derived from MSC. 3 Hematopoietic stem cells (CD34+ cells) contain osteoblast progenitor cells, implied there are functional interactions between hematopoietic and mesenchymal stem cells in adult bone marrow.