By Rob Stein,

The National Institutes of Health announced Tuesday that it has suspended funding

 new human embryonic stem cell research and that all federally funded experiments already underway will be cut off when they come up for renewal if a new court order is not overturned.

The announcement – which confirmed fears among proponents that the ruling would result in a comprehensive freeze in federal support for stem cell research – came in response to a court order Monday barring the government from funding the research because it involves the destruction of embryos.

“Frankly, I was stunned, as was virtually everyone else at the NIH yesterday, at the judicial decision,” said NIH Director Francis Collins. “This decision has the potential to do serious harm to one of the most promising areas of biomedical research.”

The Justice Department said the administration plans to appeal the ruling, but no further details were released.

In the meantime, 50 requests for new funding that were being assessed by the NIH had been “pulled out of the stack” and will not be considered further, Collins said. About a dozen other requests for $15 million to $20 million that had gone through the full review and were likely to be approved were frozen, he said. In addition, 22 grants totalling about $54 million due for renewal in September will be cut off, he said.

“The consequences of this decision are dramatic and far-reaching,” Collins said.

Another 199 grants for about $131 million that had already been awarded will be able to continue, Collins said. But those grants, including 143 worth about $95 million that are up for renewal within the next year, will be forced to stop if the situation is not resolved by the time they come up for review, Collins said.

The agency also canceled a meeting scheduled for Tuesday to consider approving new colonies of stem cells for use in federally funded experiments, Collins said.

“This is the worst possible situation,” said Elaine Fuchs, president of the International Society for Stem Cell Research. “This is going to be extremely damaging.”

Collins said he was deeply disappointed, especially at a time when the NIH was expanding its funding of the field under less-restrictive guidelines put in place by the Obama administration.

“Human embryonic stem cell research done responsibly and ethically is one of the most exciting areas of research to come along in a long time,” Collins said. “The momentum has really been building. This decision potentially places all of this in jeopardy.”

Speaking at Martha’s Vineyard in Massachusetts, where President Obama is vacationing with his family, White House deputy press secretary Bill Burton said the administration is exploring all possible avenues “to make sure that we can continue to do this critical lifesaving research,” but he did not specify exactly how it will respond.

Collins’s announcement came as opponents of the research praised the decision, supporters condemned it, lawyers debated how to interpret it and hundreds of scientists scrambled to try to determine how they would be affected.

Some hoped that the ruling would only apply to new requests for funding. Others speculated that perhaps it would only affect grants awarded under the Obama administration’s new guidelines, at least allowing research funded under President George W. Bush to continue. But administration lawyers determined that the ruling would affect all types of funding, Collins said.

“We’re still reviewing the decision from this judge, but what we’ve seen so far, from what we can tell, this would also stop the research that President Bush had allowed to go forward early in his presidency,” Burton said.

In issuing the preliminary injunction blocking, U.S. District Judge Royce C. Lamberth said it the funding violated the Dickey-Wicker Amendment, a 1999 law intended to prevent federal tax dollars from being used to destroy human embryos.

Days-old embryos are destroyed to obtain embryonic stem cells, which researcher hope will be able to cure Alzheimer’s, Parkinson’s disease, diabetes, spinal cord injuries and a host of other ailments because they can be turned into almost any type of tissue in the body. The federal government has funded research using the cells as long as the money is not used directly to destroy the embryos. Scientists have conducted studies only on cells obtained using private funding. But Lamberth ruled that distinction was invalid.

Bush had limited federal funding to experiments using 21 colonies of cells that were already in existence on Aug. 9, 2001, to prevent taxpayer dollars from encouraging the destruction of further embryos.

President Obama lifted those restrictions, and the NIH issued new guidelines to enable more cells to be eligible for federal funding. The NIH had approved 75 lines before the ruling.

Some researchers could continue their experiments using funding from private foundations and benefactors or state funding. Others could shift their research to related studies, such as examining stem cells obtained from adults or induced pluripotent stem (iPS) cells, which are created from adult cells. Critics of human embryonic stem cell research argue those cells are as good if not superior. But many researchers said embryonic stem cells remain critical, if only to be able to truly test the usefulness of the alternatives.