Isolation and characterization of multipotent postnatal stem/progenitor cells from human alveolar bone proper.

In the search for an ideal minimally-invasive multipotent postnatal stem cells' source, the aim of the present study was to isolate and characterize multipotent postnatal stem/progenitor cells from the human alveolar bone proper tissue of the oral cavity. Cells were isolated from human alveolar bone parts, immunomagnetically sorted using STRO-1 antibodies and characterized flow cytometrically for the expression of CD14, CD34, CD45, CD73, CD90, CD105, CD146/MUC18 and STRO-1 surface markers. Colony-formation and multilineage differentiation potential were tested. Mineralized tissue marker expression was examined using real time polymerase chain reaction (PCR). The cells were plastic-adherent and showed colony-formation. Cells expressed the surface markers CD73, CD90, CD105, STRO-1 and CD146/MUC18, while lacking the expression of the hematopoietic markers CD14, CD34 and CD45. Cells could be differentiated into osteoblastic, adipocytic and chondroblastic lineages. Unstimulated cells expressed alkaline phosphatase (ALP), type I, III and V collagens, osteonectin and osteocalcin in a very distinctive pattern. This study presents a practical and minimally-invasive scheme for the isolation of multipotent postnatal stem/progenitor cells from the human alveolar bone tissue of the oral cavity.