Large‐scale extraction and characterization of CD271+ multipotential stromal cells from trabecular bone in health and osteoarthritis: Implications for bone regeneration strategies based on uncultured or minimally cultured multipotential stromal cells

• Published in: Arthritis and rheumatism 2010-07, Vol.62 (7), p.1944-1954
• Main Authors: Jones, E., English, A., Churchman, S. M., Kouroupis, D., Boxall, S. A., Kinsey, S., Giannoudis, P. G., Emery, P., McGonagle, D.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Aging; Biological and medical sciences; Bone (trabecular); Bone growth; Bone marrow; Bone Marrow Cells - cytology; Bone Marrow Cells - metabolism; Bone Regeneration; Cell culture; Cell Proliferation; Cell Separation; Cells, Cultured; Child; Child, Preschool; Confocal microscopy; Differentiation; Diseases of the osteoarticular system; Fitness; Flow Cytometry; Humans; Leukocyte Common Antigens - metabolism; Medical sciences; Mesenchymal Stem Cells - cytology; Mesenchymal Stem Cells - metabolism; Middle Aged; Miscellaneous. Osteoarticular involvement in other diseases; Multipotent Stem Cells - cytology; Multipotent Stem Cells - metabolism; Nerve Tissue Proteins - metabolism; Osteoarthritis; Osteoarthritis - metabolism; Osteoarthritis - pathology; Receptors, Nerve Growth Factor - metabolism; Regeneration; Stem Cells; stromal cells; Stromal Cells - cytology; Stromal Cells - metabolism; Telomeres; Trauma; Young Adult
• ISSN: 0004-3591; 1529-0131; 1529-0131
• DOI: 10.1002/art.27451

Objective To test the hypothesis that CD45lowCD271+ bone marrow multipotential stromal cells (MSCs) are abundant in the trabecular bone niche and to explore their functional “fitness” in health and osteoarthritis (OA). Methods Following enzymatic extraction, MSC release was evaluated using colony‐forming unit–fibroblast (CFU‐F) and colony‐forming unit–osteoblast assays, flow cytometry, and confocal microscopy. CD45lowCD271+ cells isolated by fluorescence‐activated cell sorting were enumerated and expanded under standard and clonal conditions. Their proliferative and osteogenic potencies were assessed in relation to donor age and compared with those of aspirated CD45lowCD271+ cells. In vitro and in vivo MSC “aging” was measured using quantitative polymerase chain reaction–based telomere length analysis, and standard differentiation assays were utilized to demonstrate multipotentiality. Results Cellular isolates from trabecular bone cavities contained ∼65‐fold more CD45lowCD271+ cells compared with aspirates (P < 0.0001) (median 1.89% [n = 39] and 0.029% [n = 46], respectively), concordant with increased CFU‐F release. Aspirated and enzymatically released CD45lowCD271+ cells had identical MSC phenotypes (∼100% CD73+CD105+CD13+, ∼50–60% CD146+CD106+CD166+) and contained large proportions of highly clonogenic multipotential cells. In vitro osteogenic potency of freshly isolated CD45lowCD271+ cells was comparable with, and often above, that of early‐passage MSCs (8–14%). Their frequency and in vivo telomere status in OA bone were similar to those in bone from age‐matched controls. Conclusion Our findings show that CD45lowCD271+ MSCs are abundant in the trabecular bone cavity and indistinguishable from aspirated CD45lowCD271+ MSCs. In OA they display aging‐related loss of proliferation but no gross osteogenic abnormality. These findings offer new opportunities for direct study of MSCs in musculoskeletal diseases without the requirement for culture expansion. They are also relevant for direct therapeutic exploitation of prospectively isolated, minimally cultured MSCs in trauma and OA.