Researchers seeking to unlock the mechanisms of human disease will get a big boost from President Barack Obama's decision on Monday to lift US barriers on embryonic stem cell research, scientists said.
"It's a new era for stem cells research," cheered Robert Lanza of Advanced Cell Technology Inc, saying the president's action brought an end to "a sad chapter in American scientific history.
"It's unbelievable how much important research has been held up as the result of the restrictions," Lanza said.
Obama's executive order reverses former president George W Bush's ban in 2001 on federal funding for research on new lines of stem cells derived from human embryos.
Federal funding to create new lines of embryonic stem cells remains prohibited, but US scientists are now free to work with new stem cell lines acquired from private laboratories such as fertility clinics.
Calling it a "great day," Curt Civin, director of the University of Maryland's Center for Stem Cell Biology, cautioned against expecting medical breakthroughs soon but said lifting the restrictions will spur research activity.
"Experiments take time. Getting the results of these experiments on people takes even longer, sometimes years, sometimes decades. But that said, there is a lot of demand and excitement and plans for experiments and even money," he said.
Embryonic stem cells are prized by researchers because they are capable of developing into virtually every other kind of human cell, whereas adult stem cells are inherently less flexible.
"If we knew how every cell in the body makes a decision to become one kind of cell or another kind of cell, or stay asleep, not doing anything, or how to wake up normally and stay undifferentiated like cancer cells, how many diseases could we affect," said Civin.
Understanding those mechanisms will help scientists to develop strategies against disease, either through cell transplants, or new medicines or methods for preventing a given disease altogether, scientists said.
Urging research with both embryonic and adult stem cells, Civin said adult stem cells were better for transplantation and producing drugs.
"But you cannot study embryonic development except with embryonic stem cells," he said.
Harold Varmus, a Nobel laureate who heads the White House council of advisors on science and technology, said researchers must identify the best type of cells to be used in cell-based therapy, "and we are still in that process."
"What needs to be done now is to determine if those cells can substitute in therapy for human embryonic stem cells," he said.
Michael West, chief executive of California-based Biotime, believes medical advances from stem cell research could help neutralize looming budget crises linked to an aging population of US "baby boomers."
"The baby boom tidal wave will be 20 times the economic price of the crisis we are in now, and here we have potential therapies that can cut costs," he said.