What are stem cells used for?

What can stem cells be used for?

Stem cells are very fascinating for science and offer great potential for research into serious diseases for which there is currently no cure. In many research projects, adult, embryonic and induced pluripotent stem cells are used in parallel. The goals of stem cell research are diverse and can currently be described in the following categories:

Basic research

In basic research, the clarification of the molecular mechanisms of specialization of individual cells as well as the investigation of the organization of cells in tissue and organs are in the foreground. In addition, the aim is to gain a better understanding of the development and regulation of early stem cell stages and to research the mechanisms underlying the ability to multiply and differentiate.

ES cells in particular can provide valuable information about embryonic development. Above all, one would like to understand the mechanisms and molecular principles that lead to the specialization of a totipotent fertilized egg cell or the very early embryo. In addition, ES cells make it possible to better understand malformations and diseases and to prevent them in the long term.

Cell replacement therapy development

Many serious and so far incurable diseases are associated with the loss of cells that the body cannot regenerate naturally. Examples of this are neurological diseases such as Alzheimer's and Parkinson's, but also diabetes, paraplegia and heart attacks. The basic idea of ​​cell replacement therapy is to replace or repair the lost tissue with the help of stem cells. Scientists around the world are researching the development of such cell replacement therapies. The tissue replacement is particularly interesting for those tissues that have little or no regenerative capacity, such as B. Nerve tissue. Most therapies, such as those used to treat diabetes or Parkinson's, are still in (pre-) clinical research. The transplantation of bone marrow stem cells, skin stem cells and corneal stem cells in the eye has been approved to date.

The approaches that are being researched in Germany are based either on the use of adult stem cells or iPS cells. Cell replacement therapies with embryonic stem cells are also being developed in some countries, but this is not allowed in Germany.

In the meantime, the new biotechnological "tools", such as the Crispr-Cas9 gene scissors, make it possible to change the genetic material of stem cells in a targeted manner. This is particularly promising for the treatment of monogenic diseases, i.e. diseases caused by a defect in exactly one gene. So far, such approaches have only been used in clinical studies under strictly controlled conditions.

A great success for stem cell therapy was the treatment of a boy who was suffering from the so-called "Butterfly disease“(Epidermolysis bullosa) suffered. Since the patient was already so at risk from the disease (80% skin loss), a clinically not yet approved therapeutic approach was permitted within the framework of an exception with the approval of the relevant ethics committees. The body's own stem cells were removed from the boy, they were genetically modified and a skin transplant took place, which were grown from genetically modified stem cells. This experimental therapy resulted in a significant improvement in the disease and shows the importance of stem cell research.

Disease Model Development

The cellular and molecular causes of many diseases are still not well understood. What exactly happens, for example, with Alzheimer's? These questions cannot be investigated in a living patient - or only with great difficulty. Instead, researchers can now simulate diseases in the laboratory. To do this, they use reprogrammed iPS cells or stem cell lines that have been obtained from a tissue sample. In this way, scientists can gain valuable insights into the causes and courses of genetic diseases.

Further information on disease models from stem cells: http://www.stammzellen-verhaben.de/Ethik/Krankheitsmodelle.aspx

Drug testing

The development of new drugs and active ingredients is largely based on animal experiments, for example on mice. Following these experiments, a drug is tested under strictly controlled conditions in a human clinical trial. However, the results from animal experiments can only be transferred to humans to a limited extent. Researchers can therefore never be sure that a substance that is harmless in animal experiments is also harmless to humans and that it also achieves the desired effectiveness. Stem cells from human tissue are used to differentiate organ-specific cells and to use them as test systems for new active substances. In this way, more reliable results can be achieved and the number of animal experiments can be reduced in the long term.

The so-called organoids, i.e. mini-organs the size of a pea or bean, are of particular interest for testing active substances. Using the organoids, it is possible to test drugs not only in a two-dimensional cell culture, but also in a three-dimensional tissue structure that is made up of several different cell types and better reflects the natural organ structure. Stem cell lines and organoids also offer a good opportunity to test drugs that have already been approved for a different therapeutic indication. With the help of iPS technology, it is even possible to test certain active ingredients specifically on the tissue of an individual patient, for example in the case of rare diseases for which there are currently hardly any drugs