Medical: In future, our cells may repair arteries, joints, limbs

Scientists are closing in on some of the great prizes of medicine — the ability to coax our own cells to make repairs to arteries, joints, limbs and even nerve cells.

Most of the studies still involve mice or rabbits, not people. But some researchers say they're ready to move from animal models to humans.

One such group is at Yale University, where Dr. Michael Simons and colleagues reported last spring that they were able to stimulate the formation of arteries in mice and zebra fish by switching on and off two cell growth signaling pathways.

"When we disable the inhibitor mechanism, we are able to grow arteries," Simons said. 'Because we've located this inhibitory pathway, this opens the possibility of developing a new class of medication to grow arteries." It might also allow a "biological bypass" for people suffering from heart disease.

While the Yale project involves circulation to the heart, another experiment on human heart attack patients organized by an Emory University medical professor, Dr. Arshed Quyyumi, worked toward increasing circulation inside damaged hearts.

In the trial, 16 of 31 patients got standard artery clearing and stents, but also received special preparations of bone marrow cells in doses ranging from 5 million to 15 million, within a week of their heart attack. The remaining patients got the same treatment and standard medication.

Tests given three and six months later showed that the patients given the higher doses of marrow cells had greater improvement in blood flow within the heart than those who got lower doses or none at all. "The more cells a patient receives, the more beneficial effect we see in the heart,"said Quyyumi, who is working on setting up a more extensive study.

Early in August, researchers at Stanford and the University of California, San Francisco, reported they were able to use two different methods to get mouse heart cells to convert to heart muscle cells.

The Stanford team worked on shutting down a couple of tumor suppressing proteins temporarily, which allowed ordinary adult muscle cells that don't normally divide to regenerate and merge with existing heart muscle fibers as long as the suppression mechanism was restored promptly.

The UCSF team developed a recipe of three growth factors that transforms structural cells into beating heart cells that can then be transplanted back into a mouse and begin contributing to heart function within a day.

At Columbia University, researchers reported this summer they were able to regenerate rabbit joints inside the animals using bio-scaffolds treated with a specific growth factor. The rabbits were able to put weight on the joints and move well within three or four weeks from the start of the procedure.

And in a rodent study, scientists from Harvard and several other universities recently reported they were able to regenerate nerve connections that control voluntary movement after a spinal cord injury by knocking out a cell growth regulator that normally keeps connections from growing back.

Contact Lee Bowman at BowmanL@shns.com