Stem cells show potential to repair lungs in mice

LONDON (Reuters) - British researchers have successfully implanted lung cells grown from embryonic stem cells into the lungs of mice in a move that may one day provide treatments for humans with severe breathing problems.

Until now, stem cells have been seen as a promising avenue for conditions like diabetes and Parkinson's disease, but respiratory ailments have not featured because of the highly complex nature of lung tissue.

Sile Lane of Imperial College, London, said the new research was a significant advance, although it would be many years before the technology was ready for testing on people.

"Our study shows that embryonic stem cells really do have the capacity to recolonize damaged lungs," she said.

Lane told the European Respiratory Society annual congress in Stockholm that cells injected into the tail veins of mice successfully migrated to the lungs within two days, with no sign of spread to other organs.

If a similar technique works using human embryonic stem cells, it might eventually offer an alternative to difficult and costly lung transplants, as well as helping patients with serious lung damage caused by disease or accident.

Scientists will not be rushing into the clinic, however.

"Stem cells are controversial and they haven't yet been proved safe, so we don't yet know what might happen if we put them into people," Lane said in a telephone interview.

"And lung tissue is complicated architecturally and cellularly. We're going to need all kinds of scaffolds to replicate the 3-D structure."

Stem cells are the body's master cell, acting as a source for the various cells and tissues in the body. Those taken from days-old embryos, called embryonic stem cells, are the most malleable and can produce all of the cell types.

Their use is controversial because some people oppose the destruction of a human embryo. Because they are so immature, it is also difficult to control what kinds of cells they produce, leading to fears they might cause serious damage or cancer.

Lane said it was possible that stem cells could have an important role to play in lung disease even if they were not implanted into the body.

One option would be to incorporate them into gas exchangers, machines which oxygenate the blood outside the body while patients are awaiting surgery, she said.