Patients with primary osteoarthritis show no change with ageing in the number of osteogenic precursors.

The variation in marrow colony forming unit-fibroblastic (CFU-F) number in 59 patients (14-87 years of age) undergoing corrective surgery (14 controls; 14-48 years of age) or hip arthroplasty for primary osteoarthritis (45 OA; 46-87 years of age) was examined to determine whether marrow CFU-F, derived from marrow stromal fibroblastic stem cells, are maintained with the development of primary osteoarthritis (OA). Total colony number, colony size as well as alkaline phosphatase-positive colonies were determined. The mean fibroblast colony forming efficiency from the whole patient group was 2.4 x 10(-5) +/- 1.4 x 10(-5). Ageing had no effect on the colony forming efficiency or on the alkaline-phosphatase-positive colony forming efficiency, irrespective of gender. Thus precursor cells with the potential for osteogenic differentiation are maintained in OA with ageing. However, colony size showed a significant reduction with age, implying altered proliferation potential of osteogenic progenitors with ageing. This ageing effect may not be as significant in OA as in the rest of the population as bone mineral density is often preserved in osteoarthritis. As there is no apparent deficit in primitive progenitor cells, this preservation may be the result of altered regulation of osteoprogenitor activity in OA.