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 control s; 14-48 years of age) or hip arthroplasty for primary osteoarthritis (45 O A; 46-87 years of age) was examined to determine whether marrow CFU-F, deri ved from marrow stromal fibroblastic stem cells, are maintained with the de velopment 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 effic iency or on the alkaline-phosphatase-positive colony forming efficiency, ir respective of gender. Thus precursor cells with the potential for osteogeni c differentiation are maintained in OA with ageing. However, colony size sh owed a significant reduction with age, implying altered proliferation poten tial of osteogenic progenitors with ageing. This ageing effect may not be a s significant in OA as in the rest of the population as bone mineral densit y 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.