Culture expansion of cells (growing more in culture) is critical for many successful stem cell therapy applications. 99% of the basic science research has been done with cultured cells grown to bigger numbers and not with cell concentrates (like BMAC). The reason is simple, more stem cells (up to a critical number) are likely better than fewer. However, we often discuss with patients that keeping cells in culture too long will likely make them less potent, so we have a “therapeutic window” where we can get more cells. The above graph plots almost 200 knee and hip patients on reported percentage improvement in pain relief vs. the time their cells were kept in culture. As you can see, stem cells kept for less time in culture failed to produce optimal results, just as cells kept too long produced less robust results as well (in this case the “sweet spot” was around 15-17 days). Here is a snippet from our upcoming scientific paper on this issue:
“Pain relief vs. days in culture provides an interesting trend without statistical significance between the groups (10-14, 15-17, 18-20, 21+ days). However, the trends are consistent with the peer reviewed literature concerning the dichotomy between the benefits of culture expansion vs. the adverse potency effects on cells of more time in culture. For example, maximum reported therapeutic effect is seen in the 15-17 days in culture group, with less robust reports of outcome for cells cultured for les or more time. Banfi has reported that mesencymal stem cells held for longer periods in culture lose their differentiation potential and potency.[1-2] in addition, we would postulate that patients who had their cells harvested at earlier periods, failed to produce a critical number of cells for the therapy to have optimal success.”
1. Banfi, A., et al., Replicative aging and gene expression in long-term cultures of human bone marrow stromal cells. Tissue Eng, 2002. 8(6): p. 901-10.
2. Banfi, A., et al., Proliferation kinetics and differentiation potential of ex vivo expanded human bone marrow stromal cells: Implications for their use in cell therapy. Exp Hematol, 2000. 28(6): p. 707-15.