CRI听力: Stem Cell Used in Therapy in US

US scientist's have used stem cells to grow new limbs on rabbits, opening the way for doctors to re-grow broken, or diseased joints in years to come. But stem cells aren't just pushing back frontiers in animal medicine; they're already giving some seriously ill patients a second chance.

Our reporter Li Dong has the details.

Like many diabetics and smokers 58-year-old Rodney Schoenhardt had arterial blockages which cut off blood supply to the limbs. Less than two years ago he was bound to a wheelchair and faced losing a leg at the hip.

He was very scared. So he enrolled in the clinical trial run by Dr Gabriel Lasala.

Along with ten other patients Schoenhardt was given stem cell injections with the cells harvested from his own body.

Because it was a controlled trial, doctors were only allowed to inject one of his legs with stem cells. Lasala is his doctor.

"The stem cells are injected into the calf muscle. There are multiple injections, approximately 40 injections, and the injections are directed to the area where the most blood is required."

According to trial's scientists a rapid increase in movement and a reduction in pain was experienced by all the patients.

Schoenhardt remembers his relief at the sudden change.

"Two days after the stem cells were injected into my leg, I haven't had an ischemic pain in that leg. My big toe, all of my toes, totally healed. No more black, or gangrene on any of them and no pain. That is the best part. No pain."

Adult stem cells have been transplanted routinely for decades, first in bone marrow, then in procedures in which the cells were isolated and then transplanted. Each year this technique is regularly used to save the lives of tens of thousands of patients suffering from leukaemia, lymphoma and other blood diseases.

Adult stem cells aren't expected to be a cure-all and embryonic cells are still needed to grow replacement tissue for diseases like Parkinson's or diabetes. But scientists experimenting with this technology say each day is a revelation and they're learning all the time.

For now they expect adult stem cells are more likely to be most useful as laboratory tools, revealing more about the roots of disease and the potential for drug screening.

Dr Curt Civin is the director of the Center for Stem Cell Biology at the University of Maryland. He says the majority of laboratory work relies on adult stem cells, particularly investigations which are close to clinical trials.

Civin insists both types of cells need to be studied and he urges caution.

"Embryonic stem cells, iPS (human induced pluripotent stem cells) cells, still (have) a lot of work to be done and science isn't easy. You really have to be patient with it and in transplanting it to people we have to be very sure that it is better than what we are doing now and that it is not dangerous or toxic."

For CRI, I am Li Dong.