Stem cell maintenance in embryos and adults

Article By:

Sugiyama, Daisuke SSP Stem Cell Unit, Department of Hematopoietic Stem Cells, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.

Inoue, Tomoko SSP Stem Cell Unit, Department of Hematopoietic Stem Cells, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.

Kulkeaw, Kasem SSP Stem Cell Unit, Department of Hematopoietic Stem Cells, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.

Last reviewed:2012

DOI:https://doi.org/10.1036/1097-8542.YB120232

Stem cells are capable of self-renewal. Provided they have the ability to differentiate into various types of mature cells, they are classified as pluripotent stem cells. Examples of well-studied stem cell types include embryonic stem cells, induced pluripotent stem cells, and tissue-specific stem cells, which enable the corresponding tissues to sustain cell-based homeostasis and which contribute to regenerative mechanisms. These tissue-specific stem cells have been found in blood, nervous tissue, mesenchyme, and skin, and they are regulated both intrinsically and extrinsically. Intrinsic regulation is programmed by genes and transcription factors that are active in the stem cells themselves, whereas extrinsic regulation is accomplished by cytokines and matrices secreted by niche cells surrounding stem cells. Among tissue-specific stem cells, hematopoietic stem cells (HSCs) are the stem cells in the blood lineage and they have been used in patients for transplantation therapy in the fields of hematology and regenerative medicine. Most sources of HSCs rely on healthy donors and umbilical cord blood. However, problems remain in HSC transplantation, including shortages of donors and risks for donors [for example, transplant rejection and graft-versus-host disease (GVHD)]. Understanding of HSC regulation, especially with regard to niche cells, will enable us to improve HSC therapy through novel stem cell engineering.

The content above is only an excerpt.