The growth protein may speed the recovery of stroke victims, and might even restore some of the memory loss of Alzheimer's disease, according to New Scientist magazine.

A study of osteogenic protein-1 (OP-1), a man-made bone growth agent that repairs several types of damaged tissues, showed it helped rats to regain lost movement in their limbs after a stroke.

Damaged brain cells

"It works by rewiring the connections around the damaged brain cells," the magazine said. "There is also a chance that the protein may be able to improve memory in Alzheimer's patients."

Creative BioMolecules of Massachusetts developed the protein to bridge the gaps between broken bones but the company also discovered that it could stimulate the growth of dendrites, projections on brain nerve cells that receive signals to control the movement of impulses.

Test their reactions

Drug was tested on rats

Marc Charette of Creative BioMolecules and colleagues at Harvard Medical School and Massachusetts General Hospital induced strokes in rats and injected the protein into their brains to test their reactions.

The researchers measured how easily the rats could place their limbs on a nearby platform. The rodents given OP-1 recovered faster than the animals that didn't receive the protein. Higher doses of the protein also induced a quicker recovery.

"The region of the brain that is damaged dies, but the protein rewires the circuitry around the damage, through tissue surviving the stroke," Charette told the magazine.

He added that OP-1 is the first protein that seems to repair dendrites, which are destroyed by Alzheimer's disease.