US regulators have cleared the way for the world's first study on human embryonic stem cell therapy.

The move comes three days after the inauguration of President Barack Obama who has been a strong supporter of embryonic stem cell research.

Since 2001 there have been limits on federal funding for stem cells.

Geron Corp, the biotech company behind the research, plans to initiate a clinical trial in patients paralysed due to spinal cord injury.

The BBC predicted last week that the White House would reverse the restrictions placed on stem cell research once President Obama took office.

The US Food and Drug Administration gave the go ahead for the research on Friday.

Under President Bush, federal funding had been limited to around sixty stem cell lines created from embryos destroyed prior to August 2001.

Scientists had warned that only twenty eligible cell lines remain useful for research and many of these are problematic.

Researchers had told the BBC that the restrictions had slowed down their work.

Controversy

Interest in use of embryonic stem cells is due to their ability to turn into any of the body's two hundred cell types.

Using embryos donated through IVF treatment scientists have coaxed the stem cells inside into many types of tissue. One embryo can provide a limitless supply because the cell lines can be grown indefinitely.

But the use of human embryonic stem cells in research is controversial with come campaigners saying it is unethical.

Geron, a biotech company based in "silicon valley" south of San Francisco, has spent $170m on developing a stem cell treatment for spinal cord injury.

The research will use cells coaxed to become nerve cells which are injected into the spinal cord.

In animal trials of the treatment, paralysed rats regained some movement.

Company chief Dr Tom Okarma said: "What stem cells promise for a heart attack or spinal cord injury or diabetes is that you go to the hospital, you receive these cells and you go home with a repaired organ, that has been repaired by new heart cells or new new nerve cells or new islet cells that have been made from embryonic stem cells."

'Pivotal decision'

Professor Chris Mason, an expert in regenerative medicine at University College London, described the FDA decision as "historic" and a "pivotal milestone in the development of embryonic stem cell therapies.

He said: "The knowledge that will be gained in this first clinical trial deploying embryonic stem cell derived material will accelerated the development of all future stem cell therapies."

Professor Pete Coffey, director of the London Project to cure blindness, said: "It's great news for the field.

"This strengthens our recent call for regulators in the UK to help provide a clear process for researchers to take this forward.

"It's also exciting for me because it brings our own moves towards clinical trials with embryonic stem cells for age-related macular degeneration a step forward."

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Source: BBC