First trial results of human embryonic stem cells


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After more than a decade of waiting, the first results of a trial involving human embryonic stem cells have been published in a medical journal.

The Lancet reports how two women in the USA with eye disease were injected with stem cells and both apparently showed some slight improvement in vision. The company Advanced Cell Technology (ACT) says the patients are doing well four months on from the trial.

This is a significant moment because there has been so much expectation about human embryonic stem cells - which have the potential to turn into any tissue in the body.

It has been a controversial area of research in the United States. In 2001 President Bush imposed restrictions on federal funding for embryo research on moral grounds.

These were reversed by Barrack Obama in 2009.

You can read more about this area of research and about other types of stem cells here.

Study participant Julia Hawkins has Stargardt's disease

A previous trial involving spinal patients was abandoned by the US biotech firm Geron. The company said the safety trial had gone well and it had to stop the trial because of financial problems.

But the end result was that the data never made it into a peer reviewed journal.

That means the ACT trial is now the first official human embryonic stem cell trial to have reported.

One of the patients suffers from Stargardt's disease - which leads to progressive deterioration of vision. The other has age-related macular degeneration, the main cause of blindness in the developed world.

Both patients had such poor vision they were registered blind.

They both had retinal cells, derived from human embryonic stem cells, injected into the back of the eye.

After the treatment they showed some slight improvement in vision. You can read more about the trial here.

This has prompted one extraordinary newspaper headline: Once they were blind, now they see. Patients cured by stem cell 'miracle'.

I realise there is a lot of excitement about this area of research, but I would urge caution. The authors of the Lancet paper make no special claims about the study which was designed to show whether the treatment was safe.

They say: "So far, the cells seem to have transplanted into both patients without abnormal proliferation, teratoma formation, graft rejection, or other untoward pathological reactions or safety signals."

In other words the treatment did not appear to do any harm. Of particular concern was the risk of the cells forming tumours, which did not happen. This is enough to give scientists encouragement to continue the trials.

Although the study was simply designed to show safety, the researchers could not ignore the apparent slight improvement in vision of the two women.

But the authors say: "We are uncertain at this point whether any of the visual gains we have recorded were due to the transplanted cells, the use of immunosuppressive drugs, or a placebo effect."

That is crucial and shows why further larger trials are needed. As I've reported before, the European arm of this trial is being conducted at Moorfields Hospital in London.

The first British patient - a man with Stargardt's disease - was treated last week. Again, this was a safety trial rather than an attempt to improve vision.

So there is a long way to go before there's talk of miracle treatments and curing blindness.

Fergus Walsh, Medical correspondent Article written by Fergus Walsh Fergus Walsh Medical correspondent

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  • rate this

    Comment number 1.

    I do think that there is far too much medical intervention. Continued growth & development is environmental disaster & causes climate change, what for example is the carbon footprint of increased life expectancy? How much rainforest must be cleared to feed the retired? We should be in harmony with the earth & let disease run its course.

  • rate this

    Comment number 2.

    I'm sorry Wolfie but I have to disagree whole heartedly- this is nature taking it's course. Bit of GCSE biology here- there's lots of chickens (resources) so foxes have lots of food so there becomes lots of foxes. Then there isn't enough chickens to go around so there becomes less foxes and more chickens. Rinse and repeat.

  • rate this

    Comment number 3.

    You are against medical intervention? I will assume you are over 40. Some centuries ago, that would have been considered a reasonably long lifespan. It is only with what was once considered risky medical experiments has our (healthy) lifespan increased to the point where 2/3 of the people who have ever reached the age of 65 are alive today.

  • rate this

    Comment number 4.

    So - after all that time and money, embryo stem cell research may have come up with something that - gosh! - does not seem to do any harm. I suppose that's better than the previous disasters.

    Why so much obsession about embryo stem cells? Would it not have been better to invest the time, energy and money on further adult stem cell research, which already has a number of successes under its belt?

  • rate this

    Comment number 5.

    I have been observing a friend and a colleague both loosing their sight (with macular and retinal deteriorations) for a few years and know the loss they are progressively suffering so any effective treatment must be a good thing - it would certainly make me being a passenger in their cars feel a lot safer! (Neither drives at night or is as aware as I am about movements in their peripheral vision)


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