Age-related decline in the osteogenic potential of human bone marrow cellscultured in three-dimensional collagen sponges

Studies with human and animal culture systems indicate that a sub-populatio n of bone marrow stromal cells has the potential to differentiate into oste oblasts. There are conflicting reports on the effects of age on human marro w-derived osteogenic cells. In this study, we used a three dimensional (3D) culture system and quantitative RT-PCR methods to test the hypothesis that the osteogenic potential of human bone marrow stromal cells decreases with age. Marrow was obtained from 39 men aged 37 to 86 years, during the cours e of total hip arthroplasty. Low-density mononuclear cells were seeded onto 3D collagen sponges and cultured for 3 weeks. Histological sections of spo nges were stained for alkaline phosphatase activity and were scored as posi tive or negative. In the group less than or equal to 50 years, 7 of 11 samp les (63%) were positive, whereas only 5 of 19 (26%) of the samples in the g roup greater than or equal to 60 years were positive (p=0.0504). As reveale d by RT-PCR, there was no expression of alkaline phosphatase or collagen ty pe I mRNA before culture, however there were strong signals after 3 weeks, an indication of osteoblast differentiation in vitro. We performed a quanti tative, competitive RT-PCR assay with 8 samples (age range 38-80) and showe d that the group less than or equal to 50 years had 3-fold more mRNA for al kaline phosphatase than the group greater than or equal to 60 years (p=0.02 1). There was a significant decrease with age (r=-0.78, p=0.028). These mol ecular and histoenzymatic data indicate that the osteogenic potential of hu man bone marrow cells decreases with age. (C) 2001 Wiley-Liss, Inc.