Stem cells: hope or hype?
What prevents stem cell treatments from reaching their full clinical potential?
The Russian histologist Alexander Maksimov first proposed the scientific use of the term “stem cell” in 1908, when he speculated about the existence of haematopoietic stem cells. This idea of self renewing cells in the body offered hope for regenerating cells and organs lost by disease. It was not until after the second world war, however, that cell lineages could be traced with radioactive markers. Later, in the 1960s, evidence of adult neurogenesis was noted by Altman, and McCulloch and Till described self renewing cells in the bone marrow of mice.12
Research since has been carried out largely in mouse and primate models, and the properties of pluripotent stem cells are widely accepted. These cells are capable of unlimited self renewal and asymmetrical division, whereby one daughter cell resembles the mother, and the other may give rise to any cell representing each of the three embryonic germ layers—ectoderm, mesoderm, and