Scientists find lung stem cells

NEW YORK -- Scientists believe they've discovered stem cells in the lung that can make a wide variety of the organ's tissues, a finding that might open new doors for treating emphysema and other diseases.

When these human cells were injected into mice, they showed their versatility by rebuilding airways, air sacs and blood vessels within two weeks. One expert called that "amazing."

While stem cells have been found in bone marrow and some other parts of the body, it hasn't been clear whether such a versatile cell existed in the lung.

Experts not involved in the study stressed that the work must be confirmed by further research and that it's too soon to make any promises about therapies. But they said it could be a significant advance in a difficult field of research.

"These are remarkable findings and they have extraordinary implications," said Dr. Alan Fine of Boston University, who called the mouse results amazing. "But it has to be replicated."

Stem cells can produce a wide variety of specialized kinds of cells. Scientists are working to harness them as repair kits for fixing damage from diseases like Parkinson's and diabetes. Most people have heard about embryonic stem cells, which have caused controversy because embryos must be destroyed to recover them.

In contrast, the new lung cell would be an "adult" stem cell, like others found in the body. Adult stem cells maintain and repair the tissues where they're found. The bone marrow cells, for example, give rise to various kinds of blood cells, and they've been used for years in transplants to treat leukemia and other blood diseases.

The lung work is reported in today's issue of the New England Journal of Medicine by Drs. Piero Anversa and Joseph Loscalzo and colleagues at Brigham and Women's Hospital in Boston. In a telephone interview, Anversa said it's not clear what the lung stem cell normally does but that he thinks it's involved in replacing other lung cells lost throughout life.

Loscalzo said it's too early to tell what lung diseases might be treated someday by using the cells.

He said researchers are initially looking at emphysema and high blood pressure in the arteries of the lungs, called pulmonary hypertension. Emphysema is a progressive disease that destroys key parts of the lung, leaving large cavities that interfere with the lung's function.

Anversa said the cells may also prove useful to build up lungs after lung cancer surgery. It's not clear whether they could be used in treating asthma, he said.