About 550 million years ago, when animals were still in the early stages of evolution, there lived a creature who was the common ancestor of both humans and a fish species called lamprey. Lamprey is an eel-like jawless fish which has the capacity to heal its own spinal cord injuries, so is it possible humans can do the same?

A lamprey with a severed spinal cord is, like one would expect, paralyzed. But give it about 10 to 12 weeks, and no medication or treatment of any kind, and it will have resumed its full swimming behavior. Many of the genes that repair the damaged spinal cord in lamprey are also present, and active, in the repair of the peripheral nervous systems of mammals, including humans, a new study has found.

“Scientists have known for many years that the lamprey achieves spontaneous recovery from spinal cord injury, but we have not known the molecular recipe that accompanies and supports this remarkable capacity. In this study, we have determined all the genes that change during the course of recovery in the lamprey. Now that we have that information, we can use it to test if specific pathways are actually essential to the process,” Ona E. Bloom of Northwell Health's Feinstein Institute for Medical Research, one of the authors of the study, said in a statement Monday.

The researchers also took samples from lampreys’ brains and spines throughout the healing process, starting from a few hours after the injury all the way to three months later, when the healing was complete. Analyzing the samples allowed them to understand how the genes and signaling pathways that were active among the fish differed from those among individuals who had not been injured.

A European lamprey in Pirita river, Estonia, Jan. 6, 2010.

Many genes in the spinal cord were found to have changed during the course of recovery. Likewise, there were a number of gene expressions in the brain that were induced by the injury, which indicates that spinal cord injuries also change the brain.

The study also found a connection between the ability of lampreys to heal their spines and the Wnt signaling pathway that plays a crucial part in tissue regeneration, and is famously known for the role it plays among animals that display remarkable regenerative powers, like salamanders and zebrafish.

“When we treated the animals with a drug that inhibits the Wnt signaling pathway, the animals never recovered their ability to swim,” Jennifer Morgan from the Marine Biological Laboratory, also a coauthor of the study, said in a separate statement. Future research will investigate the connection between the Wnt pathway and the healing process, she added.

The paper, titled “Highly conserved molecular pathways, including Wnt signaling, promote functional recovery from spinal cord injury in lampreys” by Paige E. Herman et al, will appear this week in the journal Scientific Reports.