Wednesday November 10 2:26 AM ET
WASHINGTON (Reuters) - An experimental new drug worked to helped severed nerve cells regrow in rats, and might offer promise as a way to treat spinal cord injuries, researchers said Tuesday.
The drug, known as inosine, caused axons to grow far along the spinal cords of rats from the uninjured side to the injured side, the team at Boston Life Sciences, Inc. reported.
Axons are the long, thin arms that link one nerve cell to another.
Dr. Larry Benowitz and colleagues at Children's Hospital in Boston said they were amazed to see the axons grow so far.
``Inosine ... without known side effects, might help to restore essential circuitry after injury to the central nervous system,'' they wrote in a report in the Proceedings of the National Academy of Sciences, published on Tuesday.
Benowitz and colleagues severed one side of the corticospinal tract in rats. These axons start from the motor cortex in the brain and descend to the spinal cord.
They then infused inosine into the brain's motor cortex.
Two weeks later, they injected dye into these same brain cells, and then killed the animals to see what had happened.
In almost all of the treated animals, new axons had sprouted and spread to the area that was cut, they reported.
A few actually crossed the cut area.
They counted up to 2,500 new axons in the treated animals, compared to just a few dozen in untreated animals whose spinal cords were cut.
Inosine, which occurs naturally in the body, is a molecule formed by the breakdown of adenosine, an essential building block of DNA and RNA and an important signaling molecule.
The corticospinal tract affects almost all movement in humans, helping to activate the muscles of the fingers, hands, legs and feet.
``This is the first published study demonstrating that the corticospinal tract can be extensively reconstituted following experimental injury,'' Dr. Marc Lanser, chief scientific officer of Boston Life Sciences, said in a statement.
The drugs being developed by the company might have other uses, too, Lanser said.
``We believe that these compounds have the potential to treat other acute and chronic degenerative CNS disorders, such as stroke, Parkinson's Disease, and Alzheimer's. We hope to bring one or more of these exciting molecules into clinical testing late next year,'' he said.