Stem Cells FAQs

Kathrin Rothfischer studied microbiology and genetics in Regensburg after an excursion into German studies. Presenting complex issues in an easily understandable way was her passion even then. That is why she turned this passion into a profession after graduating: After various positions in the medical specialist publishing house and in the public press, she finally found her journalistic home at

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Stem cells are considered to be important bearers of hope for the therapy of various diseases. The most common questions about stem cells

What are stem cells?

The classic definition of a stem cell is: self-renewal and multiple development potential. This means that stem cells can renew themselves and always produce new stem cells; they are, so to speak, immortal. However, any other type of cell in the body can also arise from a stem cell. In principle, stem cells are an inexhaustible source of replacement cells with which, in theory, tissue damage can be repaired.

What is the difference between embryonic and adult stem cells?

Adult stem cells remain in many organs after the body has developed, for example in the skin or in the blood. They are also self-renewing and have regenerative potential. However, they can only form cells of a very specific type of tissue. Since they are pre-shaped, they are only suitable for cell replacement therapy to a limited extent. Embryonic stem cells, on the other hand, are a completely "blank slate". In theory, every type of cell and therefore every type of tissue in the body can develop from them.

What are pluripotent stem cells?

Pluripotent means that a stem cell can develop into all cell types of the three germ layers of the embryo and thus into all cell and tissue types in the body. The most famous example of a pluripotent stem cell is the embryonic stem cell. In recent years, pluripotent stem cells have become known primarily as so-called induced pluripotent stem cells.

What are Induced Pluripotent Stem Cells?

Scientists have succeeded in rejuvenating normal body cells with the help of certain factors and developing them back into their embryonic or stem cell stage. To do this, they smuggled certain control genes into the body's cells. From the stem cells created in this way, the researchers cultivated various types of tissue - without destroying an embryo. The risk: The artificially created pluripotency can damage the genetic material of the cells. Tumors and the development of cancer can be the result.

Why is there such a big debate about stem cells?

Embryonic stem cells are found in the so-called blastocyst, which develops between the fourth and seventh day after fertilization of an egg cell. In order to preserve these stem cells, the embryo must be destroyed at an early stage. Some accept this as a necessary evil, but for the critics it means the killing of lives. Scientists have created an ethically harmless alternative to embryonic stem cells with the help of reprogrammed body cells. However, this method is not yet fully developed. For an effective therapy, all basic mechanisms must first be clarified. A lot of research is required for this, on embryonic stem cells. Because these are the gold standard that needs to be understood.

When is the first embryonic stem cell therapy coming?

That is hard to say. In October 2010, a partially paralyzed man was treated with embryonic stem cells in the United States. This is the first official attempt at therapy with embryonic stem cells in humans. A year later, the controversial experiments were discontinued due to lack of funds - even if the cell preparation was well tolerated by the patients and there were no questionable side effects. Another study on stem cell therapy for age-related macular degeneration produced the first positive results. But that's just the beginning. In order to be able to offer a therapy as standard, several large clinical studies are necessary, which prove the safety and effectiveness of the treatment. This is time consuming and costly. According to experts, even under optimal research conditions, it can take up to 20 years before sick people can be treated with embryonic or induced pluripotent stem cells as standard.

What diseases could be cured in the future?

Expectations are high: from heart damage to diabetes, Parkinson's, multiple sclerosis, paralysis, strokes and cancer - the cellular all-rounders have an almost inexhaustible therapeutic potential. In fact, some treatment attempts have already been successful - but only in animals. Paralyzed rats, for example, were able to move their hind legs again after a stem cell injection. Scientists replaced the tissue of heart disease mice destroyed by a heart attack and cured the diabetes of diabetic rodents. The results sound promising. But as long as they cannot be repeated in humans, statements about possible therapies are a long way off.

What are the risks of a possible stem cell therapy?

What defines stem cells and why they are considered hot candidates for restoring broken tissue is also their greatest risk: unlimited growth. If stem cells get out of control, this can lead to unwanted tissue overgrowth and, in the worst case, to malignant tumors. How exactly the control mechanisms work has not yet been fully clarified. But this is necessary in order to convert stem cells into specific body cells in the laboratory.

The methods of stem cell therapy themselves also harbor dangers. Researchers can now do without the ethically controversial embryonic stem cells. But reprogramming normal body cells into induced pluripotent stem cells can damage the genetic information. Mutations may also have accumulated in the genome of the body's cells in the course of life. With the therapeutic cells grown from them, however, these genetic defects are also brought into the patient's body. That too can lead to unwanted growths and cancer.

Does it make sense to store stem cells from umbilical cord blood for your child?

Many parents think that by storing umbilical cord blood, they will ensure healing for their children in the event of illness. However, leukemia (cancer of the blood) is usually treated with foreign cord blood, as the cord blood contains diseased stem cells. If the patient is treated with these cells, sooner or later he will develop blood cancer again.

Many private providers for the storage of umbilical cord blood advertise that various diseases such as diabetes or multiple sclerosis can be cured with the help of stem cell therapy in the near future. In fact, there is still a long way to go, and nobody can say exactly when stem cell therapy will be possible in humans. The storage of umbilical cord blood is not cheap either. Storage for 20 years costs around 2,000 euros. In contrast, there are the public umbilical cord banks. Here you can donate the umbilical cord blood free of charge - and maybe save the life of another person with leukemia.

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