Nerve regeneration project holds hope for injury victims
Imagine the end of a damaged nerve as a small child lost in a forest. The child is resilient and will seek a way out, but she needs the help of a flashlight and a path.
Dr. Christine Schmidt's goal is to give the nervous system's natural healing mechanism the help it needs in repairing cells. That means supplying a tiny burst of electricity to stimulate the growth of a damaged nerve. It also means a pathway or tunnel the growing nerve can follow from the site of the injury to its destination.
Schmidt, an assistant professor of chemical and biomedical engineering at UT Austin's department of chemical engineering, recently received a three-year grant of $171,313 from The Whitaker Foundation to research ways to use electricity and an electrically conducting polymer material to stimulate nerve cell growth.
The Whitaker Foundation awarded more than $7.5 million this year for engineering research to solve medical problems and improve human health.
The nervous system consists of the brain and spinal cord, referred to as the central nervous system, and the peripheral system--which basically means all nerves leading from the spinal cord to other parts of the body.
"Peripheral nerves will regenerate to a certain extent on their own, but they don't regenerate over very long distances on their own," Schmidt said.
"Think of it as somebody lost in a forest. If it's a short distance, the regenerating nerve, or the lost person, can find the other side. If the distance is large ¾ a large piece of nerve is missing ¾ the regenerating nerve may be actively growing, but it may not actually find the other end," she explained.
The path or tunnel Schmidt is hoping will help nerve growth is just that: a minute tube composed of a black-colored material that somewhat resembles Teflon coating. Called polypyrrole, it is a polymer that conducts electricity and can be filled with nutrients that help nerves grow.
Scientists refer to the tunnel as a nerve guidance channel. The chief drawback at present is that polypyrrole is not biodegradable. Schmidt is trying to modify polypyrrole so that it will dissolve into the body and disappear as the nerve regenerates, like biodegradable sutures used in surgery.
Schmidt's research also seeks to determine the best way to use electricity in this process. No one yet understands exactly how electric fields or electric currents work to stimulate the growth of nerve cells, but plenty of studies demonstrate that they do. Schmidt will try to determine which areas of a nerve cell should be targeted, and the level and duration of electrical stimulation that works best for nerve regeneration.
"Even when we provide physical guidance, it turns out the body is limited in how far it can re-grow a nerve on its own. What we need is the right combination of good factors that will do the job," Schmidt said. "We want to regenerate nerves as fast as possible, because if nerves are disconnected from the muscles for too long, you lose muscle function."
Schmidt said the people who will benefit the most from her research "are people with peripheral nerve injuries, people who have to have reconstructive surgery on the face or arm or other parts of the body where the surgeon has to reroute nerves."
These include hundreds of thousands of Americans injured by car wrecks, gunshot wounds or other accidents every year, as well as people with malignant tumors impacting nerves.
She said the research may be very helpful to children. Reconstructive surgery can involve moving a nerve from one part of the body to the damaged area. But children are so small they don't have a lot of donor sites from which nerves can be taken.
Schmidt, who earned her Ph.D. in chemical engineering at the University of Illinois at Urbana-Champaign, is an expert in the field of tissue engineering. She was a National Institutes of Health postdoctoral research fellow in chemical engineering at Massachusetts Institute of Technology, working for 18 months with surgeons at Harvard Medical School in nerve regeneration. She received her B.S. in chemistry at UT Austin. She was a National Science Foundation Career Award Recipient this year.
Tissue engineers seek ways either to help the body regenerate naturally or to generate living cell and tissue-based therapies in the laboratory. The ultimate goal is to replace the invasive process of transplanting tissues or nerves to areas they were never intended by nature to be used, especially since this may involve multiple surgeries.
It's difficult to predict when the results from Schmidt's studies or other research on nerve repair will make it to the marketplace.
"I would think there would be some product out there within the next 10 or 15 years," she said.
Another goal for scientists working in the field of nerve regeneration is to provide help for the 235,000 Americans suffering from spinal cord injuries. "It's a little harder to predict for the spinal cord because there are so many unknowns in that area," she said.