This article is intended to give a basic understanding of what stem cells are, and their potential use for improving human health.

1. What are stem cells ?

Stem cells “have the remarkable potential to develop into many different cell types in the body during early life and growth.” Accordingly, they have the potential to regenerate tissue, thereby serving as a sort of “internal repair system” to replenish a damaged, diseased or aging tissue throughout life. This remarkable potential stems from an asymmetrical division process: “When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.”

2. What differentiates Stem Cells from other cells ?

Stem cells also have specific properties: they are not fully differentiated, and they can divide and renew themselves for long periods of time. Stem cells can be found in embryonic, fetal and adult tissues. Understanding the regulation mechanisms and processes underlying long-term self replication is critical to both basic and applied life sciences as it could lead to a true cure of degenerative diseases as opposed to merely managing their symptoms.

3. Different types of stem cells

Human embryonic stem cells are typically derived from unused 5-days-old embryos, given to science under informed consent after an in-vitro fertilization. By its very nature, this type of stem cell thus has the potential to differentiate into any of the cells of a human being. By contrast, fetal and adult stem cells have a limited spectrum of differentiation, for example, hematopoietic stem cells in the bone marrow typically differentiate into blood cell lineages only. Sometimes, the differentiation potential of stem cells is limited to very specific cellular lineages to ensure tissue renewal throughout life (e.g, skin progenitors).

4. Potential uses and obstacles

The therapeutic potential uses of stem cells -including progenitor cells- are tremendous, from curing genetic and/or degenerative diseases to curing cancer. For instance, fully controlling the processes of cellular differentiation might lead to replacement cells for regenerative medicine. Stem cells, and their progeny, could also be used to discover or test new drugs and therapies.

5. Still a long way to go…

Stem cell research is viewed as a pillar for medical innovation as it could provide realistic solutions to treat diseases and conditions for which there is no or very limited medical options today.

However many questions remain unsolved, from the potential rejection of embryonic stem cells if they are viewed as foreign cells by the patient’s immune system, to the potential damaged state of stem and progenitors cells extracted from a diseased or aging patient. Despite the fact that there is today no evidence that stem cells can actually be curative, the frenzy fueled by the myth of an “eternal life” has generated many parallel businesses, from the hundreds of companies throughout the world proposing to bank your own stem cells, to private clinics in countries with no or permissive legislation advertising treatments for desperate patients in need (stem cell tourism).

– Lauren Yeh

Sources: NIH
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