Tuesday, May 20, 2014

Obsolete from the Start

The Washington Post gave a ringing endorsement to the recent news that scientists had  succeeded once again in creating cloned human embryos and then destroying them for their stem cells (about one year ago, another team of researchers became the world’s first to successfully create cloned embryos for their stem cells, but the original somatic cells used to create those cloned embryos came from newborns and aborted fetus; this time, the somatic cells came from a 35-year old and a 75-year old).

While noting that “some ethical worries are reasonable,” the Post nonetheless concludes such worries are “not enough reason to hold back this research.”

But in endorsing human cloning to obtain stem cells, the Post conveniently – and disingenuously – ignored certain facts about the cloning process of somatic cell nuclear transfer (SCNT).  This process does not create stem cells as the Post editorial misleadingly suggests; it creates a human embryo that is then destroyed to obtain its stem cells (the Post is hardly alone in this – numerous media outlets routinely use this journalistic sleight of hand when reporting on this subject to mislead readers into believing that SCNT directly produces stem cells).

Interestingly, the Post was not always so evasive. In an editorial from 10/2/94, the Post acknowledged cloning creates a human embryo and then opposed doing this for any reason, including research and despite any theoretical therapeutic benefits. “Do we want official support of human-cloning research in this country? Do we want it anywhere?” the Post’s editors asked, and they then answered “Potential medical benefits make this a close call, but on balance the answer must be no.

The Post even used a “slippery slope” argument to oppose cloning to create human embryos for research:

“Though therapeutic cloning for parts is not the same as nurturing a human clone to birth, research that perfected the techniques needed for the first purpose would bring the second closer. It is frequently said that, whatever governments do, a human being sooner or later will be cloned. That does not relieve governments of their obligation to do what they can to block that creepy outcome.”

Moreover, on 4/10/00, the Post's editors reaffirmed this stance, and specifically opposed cloning to create human embryos for stem cell research, saying it was “flat wrong,” “unconscionable,” “alarming,” “a step too far” and that “the government has no business funding it.”  The editorial also, like the earlier one, acknowledged cloning’s “slippery-slope potential.”

In addition to the ethical problems with human cloning that the Post once so clearly acknowledged, there are practical problems with it as well. 

Cloning remains notably inefficient, requiring a large number of eggs to produce very few stem cell lines, and the process of obtaining the eggs is not without risks, some serious, to women.

The South Korean team that in April became the second to successfully clone human embryos used 77 eggs to produce 2 stem cell lines from the cloned embryos they created and destroyed.  That’s a 3 percent success rate. 

Following this development, a New York team showed a slight increase in efficiency, using 71 eggs to produce 4 stem cell lines from the embryos they created and destroyed.  That’s a 5.6% success rate.

According to the National Academy of Sciences (NAS), the potential U.S. patient populations for stem cell-based therapies are as follows:

Condition                                Number of patients
Cardiovascular disease            58 million
Autoimmune diseases             30 million
Diabetes                                  16 million
Osteoporosis                           10 million
Cancers                                   8.2 million
Alzheimer’s disease                5.5 million
Parkinson’s disease                 5.5 million
Burns (severe)                         0.3 million
Spinal-cord injuries                 0.25 million
Birth defects                           0.15 million/year

These numbers give a total patient population of 133.9 million. But as the NAS notes, these conditions “occur in many forms and thus not every person with these diseases could potentially benefit from stem cell therapies.”  Conservatively, let us say that perhaps 10% of the total will be eligible for such therapies, or 13.4 million.

At a success rate of 3%, treating this patient population with stem cells derived from cloned embryos would require an astounding 446.6 million eggs.  This in turn would require 29.7 million women to donate the average of 15 eggs per donor.

At the more efficient rate of 5.6 percent, 239.3 million eggs would be required to treat the potential patients for stem cell therapies. 

But now let’s assume scientist refine their skill at cloning to achieve a 20 percent efficiency rate; some 67 million eggs would still be required.

Let’s go even further:  assume scientists achieve an astounding 90 percent efficiency rate; some 15 million eggs would still be required.

Now let’s say scientists became so skilled, they could produce genetically matched stem cells from donors without using any eggs at all!

Oh wait….they’ve already done that.

In 2007, Shinya Yamanaka became the first scientist to reprogram a donor’s somatic cell (such as a skin cell) to generate fully pluripotent, embryonic-like, genetically matched stem cells – no eggs or embryos involved.  I’ve never used either,” Yamanaka said.  Yamanaka dubbed these stem cells “induced pluripotent stem cells” (iPSCs) because they are generated by inducing somatic cells into a pluripotent state.  So important was Yamanaka’s work to the field of regenerative medicine that within just 5 years of his discovery he was awarded a Nobel Prize.
Numerous scientists have hailed these cloning developments for the technical prowess involved in achieving them.  “I think part of the significance is technical and part of the significance is historical,” said John Gearhart, one of the first scientists to isolate, in 1998, human embryonic stem cells.

But they also noted that the therapeutic value for cloning is probably not much.  According to Gearhart,”the more we learn about reprogramming, the more I think IPS will be the one of choice."  Similarly, commenting on the work of the Oregon team that first succeeded in creating cloned human embryos in 2013, MIT professor Rudolf Jaenish, a vocal proponent of cloning for research, called that development “an outstanding issue of whether it would work in humans has been resolved,” but one, he added, that “has no clinical relevance.”

Non-embryonic stem cells are already achieving many of the therapeutic benefits the Post now posits as merely potential for stem cells derived from cloning. For example, scientists are producing whole organs from patients’ own adult stem cells, such as tracheas that have already saved people’s lives.

One wonders what has changed in the scientific and ethical calculus to make the Post now embrace what it once abhorred – especially since the argument for a need to go down this path is weaker than ever. 

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