Can Stem Cells be Used to Create People?

Group of sperm going for an egg, 3d illustration.

We’ve known about stem cells for half a century. They are cells that not only make copies of themselves but can also become other types of cells and tissues. This kind of biological feat is unique in science and has the potential to cure disease. So why haven’t we seen more scientific success and stem cell therapies? Where’s the beef?

Jewels Within Jewels

Like good wine, good science takes time to mature and have its potential fully realized. This is exactly the case with stem cell science. Take reproduction. Ten years ago, we published that human sperm precursors, termed spermatogonial stem cells, can create not only sperm, but also other organs in the body. We call this “multipotency” or “pluripotency,” and it suggests that the adult human testicle contains some nifty and powerful stem cells. But neither human sperm nor other organs have been made from these cells over the last decade.

What takes so long is trying to understand how stem cells reproduce themselves or turn into other tissues. This all has to do with getting to know where they live, termed their “niche,” what signals they get, and how they respond to these signals. The science has progressed very quickly in rodents and other mammals, but as you know, humans are…well…different. And figuring out exactly how rodents and men differ has been the Achilles heel of stem cell research.

A Shining Jewel

So, it was nice to see some serious progress in reproductive stem cell science recently published by a large team of researchers. To simulate a potential method of fertility preservation in boys receiving sterilizing cancer treatment, the researchers took testicular spermatogonial stem cells from prepubertal monkeys and then froze them. The monkeys then received sterilizing chemotherapy and recovered. After the monkeys passed through puberty, the researchers thawed the frozen stem cells and implanted them under the skin of the monkeys from which they were taken. The testis tissue grafts made mature sperm which was then harvested and used with IVF-ICSI to make a healthy baby monkey. Years of preparation, four universities, one baby monkey. That’s hard work.

Using stem cells to make sperm outside the testicle. Another advance in stem cell science. Granted, the natural fertility of these monkeys was not restored, monkeys are not humans, and the steps used aren’t that easy to translate into the clinic. But this proof-of-concept study is a cellular leap in right direction.

6 thoughts on “Can Stem Cells be Used to Create People?

  1. Dear Dr Turek, do we know how far away we are from stem cell treatment? I recently had the FNA mapping in London and the result was unfortunately Sertoli Cell Only, with no evidence of germ cells. I expect there has never been a success with mTese after an FNA Mapping with this result?

    I’d be grateful for a reply, many thanks.

    1. Dear Joe, We are SOME years away from using stem cells to make sperm for patients. I’d say 10 years, partially because the knowledge that’s needed to do this safely and also because of the politics involved. All I can say is that no one that I know of has found mature sperm by any method after an FNA mapping procedure performed by me has shown no sperm.

  2. Dear Dr. Turek,

    I have been diagnosed with severe non-obstructive azoospermia. A few weeks ago I had Micro Tese and biopsy of testicles where they had not found any sperm. In 70-80% of tissue from biopsy they have found nothing and in 20-30% they have found cells with mostly primary spermatocytes and rare and mainly individual or in smaller groups oval spermatids.

    My testicles are normally sized, all hormones normal including inhibin B and also all genetic tests were ok.

    As I stated above I would like to hear your opinion if there is a chance for me to become a biological father or my wife and I should go with sperm donation program?

    Do you think that FNA mapping of testicles would have a chance of getting some different results from Micro Tese in my case?

    1. Ivan, so sorry to hear about your failed mTESE procedure. In fact, we have published that in 29% of men in whom mTESE fails, FNA Mapping can actually find mature, usable sperm! Its just different in the way it finds it. You must wait at least 6 mos after the mTESE procedure to do this though. Give us a shout!

  3. Is there any solution for non obstructive azoospermia and at the same time I have reciprocal translocations between chromosomes Y and 2. I have done TESE but no mature sperm found. Only spermatid

    1. Dear Ziad, Usually the type of chromosomal abnormality only tells you WHY you have no ejaculated sperm but typically does not mean that you don’t have SOME testicular sperm. The quality of the sperm retrieval procedure is also very important. So, you might consider a Second Opinion with us to determine whether sperm might still be found despite a TESE procedure not showing it. I always say: “Where there are spermatids, there are usually sperm…”

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