Enzyme Found To Help Formation of New Axons

Greg George writes "Researchers at Emory University and Georgia Institute of Technology have announced that they have found an enzyme that helps nerves to grow in areas damaged after trauma. In typical injuries, scar tissue forms around the damage point and the body removes the tissue so that new muscle and nerves can regrow in the damaged area. In spinal cord injuries, scar tissue forms and that is the end of the story. Special chemicals form that stop the body's cells from moving in and removing the scar tissue and then allowing the healing process to start. Studies have been done attempting to bypass the scar tissue, but none has been successful in large-scale repair of injured muscle and nerves in the spinal column. The researchers for this paper have found that sugar proteins near the damage point stop the healing and that an enzyme can be used to break down these proteins so that the body can then begin repairs. The enzyme, chondroitinase ABC (chABC), is sensitive to heat, and breaks down quickly in a human body. To stop that process they found that by replacing the ABC with another sugar called trehalose, they were able to stabilize the ABC, allowing it to break down scar tissue over a large area. The gel formed by these sugars is stable for up to six weeks in the bodies of test animals, allowing the research team to inject growth factors that increased the healing, to the point that the animals started to use their limbs again. The work is still in the beginning stages." Reuters reporting adds a few more details: "...many other approaches will be needed to repair spinal cord injuries in humans, including controlling inflammation, which can cause additional injury, stimulating nerve fiber growth, and getting nerves to reconnect and communicate with the brain."

Comments

Link to Scientific Article

[structural_biologist]

Here's the actual research paper being cited:

Lee H, McKeon RJ, Bellamkonda RV. Sustained delivery of thermostabilized chABC enhances axonal sprouting and functional recovery after spina chord injury. Proc. Natl. Acad. Sci. USA 2009. doi: 10.1073/pnas.0905437106.

The summary is slightly incorrect in saying that this group discovered that the chondroitinase enzyme can aid in recovery after spinal cord injury (this has been known for a while, see Bradbury et al. (2002) Nature 416:636–640, whom the authors cite). The authors contribution is to engineer a version of the enzyme that is more stable and works better than the natural version of the enzyme. Because the enzyme is more stable than the natural enzyme, the authors can implant a hydrogel at the site of injury that slowly releases the enzyme over the course of two weeks. The authors show that this sustained delivery improves neuron regrowth and the locomotor function of the injured animals compared to just a single dose of the natural enzyme (which degrades relatively quickly after injection).

Re:Evolutionary Advantage?

[roguetrick]

The Central Nervous system has its own types of cells called glial cells that are very specialized. These cells provide everything from an immune response to creating a framework for growing neurons. This is advantageous because one of the first structures to develop in an embryo is the central nervous system and having an enclosed environment keeps the CNS from having to deal with a lot of the problems that the other environments of the body have to deal with. It is really a pretty amazing system, you should check it out.

Re:You can't.

[Hatta]

There are many more researchers than there are funds. If anything, we produce too many grad students for the available positions. More money would employ more researchers, and more science would get done.

Re: group selection

[mr_overalls]

This would make sense if genes operated at the group level. They do not. Groups selection is pretty much discredited as a mechanism of evolutionary change. http://en.wikipedia.org/wiki/Group_selection

Re:tl;dr

[SydShamino]

It'll be hard to get another celebrity to put their weight behind this kind of research

You are incorrect.

I spoke recently with Doctor Charlotte Smith of the Spinal Cord Injury Recovery Center at Brackenridge Hospital in Austin, Texas, who has seen regrowth of spinal nerve cells in patients undergoing umbilical cord stem cell treatment combined with computer-controlled direct stimulation of detached nerves.

Her research continues to attract funding, but it began from a rehabilitation center significantly funded by former and current professional football players. Consider someone like Kevin Everett, who, after 15 minutes as a quadriplegic ended his football career, has devoted his time and effort toward raising money for spinal cord research.

While the brutality of professional football injuries can be tragic, it does instill in many players a need to campaign for a cure. These are the celebrities that step up and put their weight behind the research.