Mesenchymal precursor cells in the blood of normal individuals

TLDR

Mesenchymal precursor cells in normal blood adhere to plastic and glass and proliferate logarithmically in DMEM‑20% fetal calf serum without added growth factors. When cultured with osteogenic supplements, these cells differentiate into osteoblast‑like cells that express alkaline phosphatase (enhanced by BMP‑2), with 30 % becoming osteocalcin‑positive after two weeks, while the cultures also generate adipocytes, multinucleated giant cells, and express mesenchymal markers such as vimentin, type I collagen, BMP receptors, and CD105.

Abstract

Mesenchymal precursor cells found in the blood (BMPCs) of normal persons adhere to plastic and glass and proliferate logarithmically in DMEM-20% fetal calf serum (FCS) without growth factors. They form cells with fibroblast-like and stromal morphology, which is not affected by eliminating CD34, CD3, or CD14 cells. Osteogenic supplements (dexamethasone, ascorbic acid, and β-glycerophosphate) added to the culture inhibited fibroblast formation, and BMPCs assumed the cuboidal shape of osteoblasts. After 5 days in supplemented medium, the elutriated cells displayed alkaline phosphatase (AP), and the addition of bone morphogenetic protein (BMP)2 (1 ng) doubled AP production (P < 0.04). Two weeks later, 30% of the cells were very large and reacted with anti-osteocalcin antibody. The same cultures also contained sudanophlic adipocytes and multinucleated giant cells that stained for tartrate-resistant acid phosphatase (TRAP) and vitronectin receptors. Cultured BMPCs immunostain with antibodies to vimentin, type I collagen, and BMP receptors, heterodimeric structures expressed on mesenchymal lineage cells. In addition, BMPCs stain with anti-CD105 (endoglin), a putative marker for bone-marrow mesenchymal stem cells (MSCs).