Figure 1. Long-term growth curves of mesenchymal stromal cells (MSC).

Cells were isolated from human bone marrow from the iliac crest (BM) or from the femoral head (HIP) of donors that were either young (21–25 years), median aged (44–55 years) or old (80–92 years). Cell numbers were determined at the end of every passage and cumulative population doublings (PD) were calculated in relation to the cell numbers at the first passage.