Thread: haemopoiesis on stromal layers

Could someone explain these results, they are from an old paper.

Bone marrow HSC are plated over adherent stromal cells and let to grow for 10 weeks. Stromal cells support HSC growth and every week half of the HSC is taken out of the flask and cells counted. These cell counts are increasing from week 1-3 and then start to drop until week 10. Why is it increasing for the first 3 weeks.

Half of the HSC that is taken out and counted (from the above flask) is then plated into methylcellulose for 2 weeks and generated colonies counted (HSC progenitors will form colonies of differentiated cells, CFU-GM, CFU-B…). Colony numbers here start to drop straight away, from week 1 and continue to decrease till week 10?

Any idea what is going on?

Many thanks!