Abstract
Introduction
Iliac crest bone marrow aspirate (ICBMA) is frequently cited as the ‘gold-standard’ source of MSCs. Mesenchymal stem cells have been shown to reside within the intramedullary (IM) cavities of long-bones and a comparative assessment with ICBMA has not yet been performed.
Methods
Aspiration of the IM cavities of 6 patients' femurs with matched ICBMA was performed. The long-bone-fatty-bone-marrow (LBFBM) aspirated was filtered (70μm) and the solid fraction digested for 60min (37°C) with collagenase. Enumeration was performed via the colony-forming-unit-fibroblast (CFU-F) assay and using the CD45low CD271+ phenotype via flow-cytometry. Passaged (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages with their phenotype assessed using flow-cytometry CD33 CD34 CD45 CD73 CD90 CD105.
Results
MSCs were isolated from all fractions. Using the CFU-F assay median number of colonies: ICBMA=8 (2–21), LBFBM-liquid=14 (0–53), LBFBM-solid=116 (23–171) per 200μl of sample; MSC frequency, as percentage of total cells, using flow-cytometry, provided similar results. Mesenchymal stem cells isolated from the LBFBM phases appeared to not be inferior to ICBMA in terms of osteogenic, chondrogenic or adipogenic differentiation. Passaged cells from all fractions had a phenotype consistent with other reported sources.
Discussion
Intra-medullary cavities of long-bones are frequently accessed by the orthopaedic/trauma surgeon. This represents a ‘low-tech’ method of harvesting large numbers of MSCs with a favourable differentiation profile for autologous/allogenous uses.
