Stem Cells from Testicular Biopsy

Prof. Hassenfuss, could you briefly describe your discovery?

Let me first tell you that this is collaboration between the department of Cardiology and the department of Human Genetics. We, as cardiologists, are interested in stem cells as they may be an excellent resource for treatment of heart failure in the future. Our colleagues from Human Genetics have been interested in spermatogenesis and this is how we decided to look for spermatogonial stem cells with respect to regenerative medicine. We managed to isolate adult spermatogonial stem cells from adult mice and we brought these cells into culture to modify those cells and under those culture conditions these cells gained pluripotency similar to embryonic stem cells. Our adult spermatogonial stem cells under in vitro culture conditions are comparable with respect to pluripotency to embryonic stem cells and from this pluripotent cells in culture, we can derive all different kind of tissues such as spontaneous beating hearth cells, liver cells, skin cells, and vascular cells.

So, precisely, can these cells produce any kind of bodily cells?

Actually, there are about 250 different cells in the body and we didn't check for every cells but we think that this cell is pluripotent and so far every cell we were looking for, we were able to gain out of this pluripotent cell. The cell culture approach is the same that has been described for embryonic stem cells. So the important step is to isolate the spermatogonial stem cells and to bring them in culture and let them gain the same properties as embryonic stem cells.

What are the implications of you discovery in the stem cell research field?

You are aware of the immunological problem associated with embryonic stem cells and, in particular, of the ethical problem associated with human embryonic stem cells. Now, if we can transfer our technique to human tissues then we would be able to gain from testicular biopsy cells that are pluripotent and have the same properties than embryonic stem cells. So this would avoid completely the ethical problems associated with embryonic stem cells, provided that we will be able to develop the same system in human tissue.

Do you plan to move your work into humans?

Yes, this is what we are doing right now.

In the same issue of "Nature" Prof. Takashi Shinohara, who has tried to do similar experiments, says about your discovery "It's too good to be true"...

Well, what should I say? This is a comment. We managed to do it. We did it from different approaches from transgentic mice in which spermatogonial stem cells specific gene is coupled to fluorescent protein in order to be able to identify these cells and later we managed to identify these cells from different mice strain. "Nature" was asking us for a large number of controlled experiments so I think the data are there and everybody can look in the paper and try himself.

You filled for an international patent does it mean that you research already interests the industry?

Yes

For what kind of development?

Of course for medicine it is of great interest to develop regenerative strategies and our approach, if it is completely transferable to human tissue, would allow to isolate and identify pluripotent human stem cells which could be used for different kind of regenerative medicine. In particular we would be interested in the regeneration of the heart in situations of heart failure. It could be also very interesting for treatment of Parkinson disease. I would expect that we can obtain pancreatic cells as well to produce insulin so it would also be very interesting for treatment of diabetes.

Regenerative medicine raises a lot of hopes, how far do you think we are away from the first treatment?

I think we are just at the beginning and we need a lot of basic science to find out what kind of diseases we can treat, what cells we need, what could be the problems for the patients with respect to development of tumours, with respect to immunological rejection and all kind of things. So I think we are right at the beginning but there are good reasons why we could be optimistic.

Prof. Hasenfuss, thank you.

Prof. Hasenfuss works at the Hearth Center of the George August university of Gottingan

By Gilles Prigent and Francesca Gilibert