Washington, April 25 (Reuters): Alzheimer?s patients given gene therapy seemed to regrow some damaged brain cells and seemed to experience a slower loss of their ability to think and remember, US scientists reported yesterday.

The trial therapy was not without danger, however.

Two patients who were treated while conscious but sedated suffered brain damage when they moved during the procedure. One died five weeks later.

The treatment did appear safe if done under general anesthesia, the team reported in the journal Nature Medicine, and they said they will try it in a larger group of patients.

For this gene therapy experiment, researchers took skin cells from eight patients with mild Alzheimer's disease. They genetically modified the cells to produce a protein called nerve growth factor, or NGF, a protein that prevents cell death and stimulates cell function. They then infused these genetically engineered cells back into the patients' brains.