Haematopoiesis: “living in the shadow” of stem cell differentiation.

Haematopoiesis is one of the most well understood stem-cell associated processes. It is a process in which pluripotent hematopoietic stem cells (HSCs) self-proliferate and differentiate into all types of blood cells. The process takes place in marrow of the flat bones in adults, however its location changes several times through embryonic and foetal development. Given the broad range of blood cells and the major differences in their build and function, together with the fact that their numbers need to be maintained within relatively narrow margins in order to maintain homeostasis despite changing environmental conditions, makes the whole process of haematopoiesis highly regulated and depending on a variety of growth factors. When influenced by those, HSCs undergo several irreversible steps, with every next one committing them to an even more specialised fate, ending with all the specific types of mostly short-lived blood cells, that are unable to proliferate on their own and need constant replenishment from the HSC pool. Because the process of haematopoiesis is the only source of all the members of the group of cells performing a range of highly important roles in functioning of the organism, significant damage to the underlying stem cells can cause a range of severe diseases. Many treatments are suggested for managing their symptoms or slowing progress, with bone marrow transplant being one of the only ones that offer possible permanent solution and, despite being a relatively risky procedure, is being widely performed, with the methods constantly improving in order to achieve progressively better results in both treatability and survivability of the patients.