New Possibilities for the Use of Stem Cells in Medicine
9 Apr, 2006 12:11 am
Adult Spermatogonial Stem Cells Behave Like Embryonic Stem Cells
G?ttingen Medical Researchers Present World Novel Research Results in the Scientific Magazine "Nature"
"We have laid the basis for a future treatment of severe illnesses like cardiac insufficiency with the help of a body´s own stem cells", says cardiologist Prof. Dr. Gerd Hasenfuß.
"We have isolated
spermatogonial stem cells from adult male mice", says Priv. Doz. Dr. Karim
Nayernia, Dept. Human Genetics. These cells are physiologically responsible for
the continuous production of sperm cells. The Göttingen scientists now showed
that these cells, when cultured in a test tube, can be brought into a condition
that mimics that of embryonic stem cells. The cells form a cell mass (embryoid
body), which can differentiate into various if not all cell types of the
organism. During their research, cardiac muscle cells developed after several
days of cultivation. These cells contracted rhythmically in a way cardiac cells
do. Biochemical and physiological analysis clearly identified the cells as cardiac cells. They could clearly be distinguished from skeletal muscle cells, which were also observed to grow spontaneously. Further, the cells could be influenced to develop into specialized nerve cells which produced dopamine, a factor that is missing in Parkinson´s Disease. Other cell types such as vascular-, skin-, liver-, pancreatic-, and blood cells could also be obtained from these stem cells.
"The ability of the cells to differentiate into a large variety of tissues has so far only been observed in embryonic stem cells", says Dr. Kaomei Guan, Dept. of Cardiology and Pneumology at the Cardiac Centre Göttingen. The invention and its application have been filed for an international patent and will be realized by the MBM ScienceBridge GmbH, a technology transfer organization of the Georg August University Göttingen.
At present, the Göttingen scientists are trying to identify equivalent stem cells from humans. The analyses are performed on testicular biopsies taken during urological examinations. "Should our results hold true in humans, immunological as well as ethical problems with the use of human embryonic stem cells would be solved", the scientists Prof. Dr. Gerd Hasenfuß, Prof. Dr. Wolfgang Engel, Dr. Kaomei Guan, and Priv. Doz. Dr. Karim Nayernia state together.
On the basis of these cells, new stem cell techniques could be developed in order to treat a variety of illnesses. To do so, the spermatogonial stem cells would be harvested from a male patient, cultivated in a test tube (in vitro), and re-transplanted into the same patient.
A danger of rejection of the new tissue does not exist in this so called autologuous transplantation. Possible fields of application are the treatment of heart failure, of Parkinson´s Disease, and of Diabetes mellitus.
Answering to the question of whether these cells qualify for the treatment of male patients only, Prof. Dr. Wolfgang Engel said: "At present, yes. Although a further development of the technique is conceivable, that would allow a different person to donate the stem cells. Furthermore, it has been known for some time that the female organism, too, harbours stem cells, that are responsible for the production of eggs. In analogy to spermatogonial stem cells, these cells could be used for the production of pluripotent stem cells."
Background Information on the Nature Publication
The term "stem cell" is associated in biomedical research with the hope to treat thus fare incurable illnesses and to avoid organ transplantations. Specialized organ cells have normally lost the ability to divide. Their death in the course of an illness therefore leads to a loss of function within a given organ and to a replacement by scar tissue. In contrast to organ cells, undifferentiated stem cells have the ability to multiply and form differentiated daughter cells. Scientists differentiate between embryonic and adult stem cells. Embryonic stem cells develop from the inner cell mass of an embryo, called blastocyst that can be harvested beyond the embryonic eight cell stage. Embryonic stem cells can develop into all cell- and tissue types of the organism. They are pluripotent but not totipotent. The so far identified adult stem cells show a limited ability to divide and to differentiate.
The great potency of embryonic stem cells for the regeneration of organs contrasts with immunological and, above all, ethical concerns. Because the embryo, from which the cells are taken, is immunologically different from the organism that receives the cells, scientists fear that the receiving organism may reject the tissue. This immunological problem could be solved by means of genetic techniques or with the help of therapeutic cloning. More severe are ethical concerns along with the application of embryonic stem cells and with therapeutic cloning. Legal basis in Germany is the Embryo Protection Act, according to which embryos can only be produced with the objective of reproduction. Human embryonic stem cells cannot develop into a complete human organism, but they still have to be harvested from embryos. In Germany, the use of human embryonic stem cells underlies strict legal regulations since June 2002. Research on embryonic stem cells is only permitted after severe examination and only on such embryonic stem cells that are imported from other countries and have been created extra-corporally with the aim to bring about a pregnancy.
The term "stem cell" is associated in biomedical research with the hope to treat thus fare incurable illnesses and to avoid organ transplantations. Specialized organ cells have normally lost the ability to divide. Their death in the course of an illness therefore leads to a loss of function within a given organ and to a replacement by scar tissue. In contrast to organ cells, undifferentiated stem cells have the ability to multiply and form differentiated daughter cells. Scientists differentiate between embryonic and adult stem cells. Embryonic stem cells develop from the inner cell mass of an embryo, called blastocyst that can be harvested beyond the embryonic eight cell stage. Embryonic stem cells can develop into all cell- and tissue types of the organism. They are pluripotent but not totipotent. The so far identified adult stem cells show a limited ability to divide and to differentiate.
The great potency of embryonic stem cells for the regeneration of organs contrasts with immunological and, above all, ethical concerns. Because the embryo, from which the cells are taken, is immunologically different from the organism that receives the cells, scientists fear that the receiving organism may reject the tissue. This immunological problem could be solved by means of genetic techniques or with the help of therapeutic cloning. More severe are ethical concerns along with the application of embryonic stem cells and with therapeutic cloning. Legal basis in Germany is the Embryo Protection Act, according to which embryos can only be produced with the objective of reproduction. Human embryonic stem cells cannot develop into a complete human organism, but they still have to be harvested from embryos. In Germany, the use of human embryonic stem cells underlies strict legal regulations since June 2002. Research on embryonic stem cells is only permitted after severe examination and only on such embryonic stem cells that are imported from other countries and have been created extra-corporally with the aim to bring about a pregnancy.
See also interview with Pr Gerd Hasenfuß
