Given the following data, assess whether human hematopoietic stem cells can truly self-renew in vivo. & About 400 billion mature hematopoietic cells are produced daily.
The best estimate of the Hayflick limit is 44 to 50.
About 1:5000 progenitors do NOT apoptose.
About 50 to 1000 mature cells are made per progenitor (6 to 10 doublings).
The entire differentiation pathway may be 17 to 20 doublings (soft fact).
About 10 to 30 million cells at most can be made from a highly purified single hematopoietic stem/preprogenitor cell in vitro.
Present order of magnitude calculations in constructing your decision. Also perform parameter sensitivity analysis of each of the parameters that govern the hematopoietic process. How important are the parameters that govern telemorase activity in determining the total number of mature progeny produced over a person's lifetime?