January 23, 2021

The Niche

Trusted stem cell blog & resources

Stem cell story of the year: human therapeutic cloning

There have been many interesting developments in stem cells in 2013, but to me the biggest event by far was the first ever successful somatic cell nuclear transfer (SCNT)-based human therapeutic cloning.

This approach generated apparently genetically normal human embryonic stem cells (hESC), an astonishing accomplishment.

Knoepfler Diagram Human Cloning
Two kinds of human cloning. Knoepfler illustration.

There are two kinds of human cloning: therapeutic and reproductive. The latter is making an actual new person with an identical genome to an existing person. The latter has never been achieved, but some of us are worried it is coming sooner than most imagine. See image above that visually explains the 2 kinds of cloning, adapted from my new book on stem cells: Stem Cells: An Insider’s Guide.

Shoukhrat Mitalipov
Shoukhrat Mitalipov.

“Human Embryonic Stem Cells Derived by Somatic Cell Nuclear Transfer” was the human therapeutic cloning paper published in Cell  by the lab of Shoukhrat Mitalipov (left) at Oregon Health Sciences Universities (OHSU).

The paper also generated great controversy because of several instances of data duplication and the incredibly short review period of just a few days.

In terms of the discovery itself, an OHSU press release described it this way:

Somatic cell nuclear transfer (SCNT) is a technique in which the nucleus of a donor cell is transferred to an egg cell whose nucleus has been removed, generating embryos that are almost an identical genetic match to the donor individual. For the first time, a team of scientists has used SCNT to produce human embryonic stem cells (hESCs). This milestone, published by Cell Press May 15th in the journal Cell, opens up new avenues for using stem cells to understand patient-specific causes of disease and for developing personalized therapies.

Dr. Mitalipov, who I had the chance to meet and talk with at the recent World Stem Cell Summit calls the hESCs made by therapeutic cloning (NT-hESC).

For me human therapeutic cloning is the stem cell event of the year because it has such powerful implications at a global level.

On the one hand, NT-hESC present an alternative to iPS cells as a basis for personalized medicine. In principle, any sick patient could have NT-hESC made from them and then used as a basis to produce specific differentiated cells that when given back should be accepted by the body as “self”. There is huge positive potential there and reason for hope. Don’t get me wrong, I think iPS cells are incredibly powerful, but having more stem cell “weapons” against disease is definitely a good thing.

On the other hand, I believe that therapeutic cloning opens the door to eventual human reproductive cloning. It’s an unintentional consequence as Mitalipov told me earlier this year he is opposed to human reproductive cloning. However, that doesn’t mean that some rogue group will not try to clone a person. In fact, I think it will happen in the next 5-10 years.

The controversy surrounding the lightning fast review of the paper and the problems with some figures in the paper that were entirely missed by editors and reviewers also has lessons for the field as well.

So for all these reasons, positive and negative, I think human therapeutic cloning is the stem cell event of the year for 2013.

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