Pain Essay, Research Paper

Vaccine Could Protect Against Stroke And Epilepsy Damage

February 25, 2000

A new oral vaccine has offered new hope because of its effectiveness in protecting laboratory rats against brain damage from epilepsy and stroke, and might one day be used to help humans with the same conditions. The vaccine blocks a protein in the brain called NMDA, but does so only when epilepsy or stroke occur. The vaccine is released in the brain as needed and is protected from any side effects. During and colleagues immunized another group of rats and after five months induced stroke in them by blocking an artery in the brain. The rats still experienced strokes, but the size of the brain damage was 70 percent less in immunized rats compared with animals that didn’t receive the treatment. This concept could be useful in treating other neurological disorders as well. NMDA is a receptor that responds to the chemical glutamate in the brain, the glutamate/NMDA complex is responsible for many normal brain functions like the development of neurons, learning and memory. Blocking the NMDA receptor in general could have damaging effects. However, the NMDA receptor is also involved in a chain of events that contribute to neurological damage from epilepsy, stroke and head injuries. To create the vaccine, the researchers added the gene that codes for the NMDA receptor to a virus. When this gene and virus combination enter the animal’s bloodstream, the immune system creates antibodies to both the virus and NMDA. These antibodies circulate in the blood, but are prevented from entering the brain by the blood brain barrier, a tightly packed group of cells that line blood vessels in the brain. The blood brain barrier is a protective mechanism that prevents many large molecules, such as these antibodies, from entering the brain. Yet during times of neurological insult, like epilepsy and stroke, the blood brain barrier is compromised, and the antibodies do enter the brain. They then seek out and block the NMDA receptor, preventing some brain damage from occurring. Soon afterwards, the blood brain barrier is restored, and the antibodies no longer have an effect on the brain.

The biotechnological aspect of this article is evident because of the lengthy research and use of lab rats to secure the validity of this new approach to reduce the risk of brain damage after seizures or strokes. The scientists involved first isolated a receptor in the brain, understood its functions, and then found a way to block its effects that can be detrimental to the brain after a stroke.

Although this new form of treatment has not been tested on humans, I believe that this will lead to some very helpful discoveries. The potential this treatment has is immense and usefulness unknowable. If one of my family members were to have a stroke and come out nothing like his/her former self I would certainly wish that there had been something to prevent the brain damage from occurring.

Vaccine Could Protect Against Stroke And Epilepsy Damage

February 25, 2000

An oral vaccine has proven to be effective in protecting laboratory rats against brain damage from epilepsy and stroke, and might one day be used to help humans with the same conditions. The vaccine blocks a protein in the brain called NMDA, but does so only when epilepsy or strokes occur. Therefore, the brain is helped by the vaccine in times of need, yet is protected from any side effects like deficits in movement, learning and memory that could result from blocking NMDA during normal brain functioning. “We’ve known for a long time about the mind-body connection how the brain talks to the immune system,” said Dr. Matthew During, professor of neurosurgery at Jefferson Medical College in Philadelphia. “Here, we’re saying the opposite the immune system talks to the brain and that can be used as a very powerful tool, almost a scalpel, to target specific receptors in the brain.” The researchers, led by During, began by giving the vaccine to 100 rats, and a month later, induced epileptic-like seizures in them with a drug called kainate. Although normally 70 percent of rats given kainate would have seizures, only 20 percent of the rats that were previously immunized experienced seizures. During and colleagues also immunized another group of rats and five months later induced stroke in them by blocking an artery in the brain. The rats still experienced strokes, but the size of the brain damage was 70 percent less in immunized rats compared with animals that didn’t receive the treatment. The study appears in the February 25 issue of the journal Science. The report was collaboration among scientists at Jefferson Medical College and the University of Auckland in New Zealand. The researchers then tested the animals’ behavior to see if the treatment had any unwanted effects. “Not only weren’t the animals impaired, but if anything, their learning and memory were facilitated,” said During. “It’s important with this type of a strategy to be certain that the antibody is not going to attack normal brain tissue,” said Dr. Steven Warach, chief of the section on stroke diagnostics and therapeutics at the National Institute of Neurological Disorders and Stroke (www.ninds.nih.gov) in Bethesda, Md. “There’s still a lot of work that needs to be done. However, this is a novel, innovative and promising approach looking at potential stroke therapies,” said Warach. Warach, who was not involved in the study, added that even if this specific treatment is not developed into a drug for human use, it could serve as an effective tool to study epilepsy and stroke in the pre-clinical laboratory. “The question of whether this will become a therapy for human stroke will depend a lot on intervening research even before we get to clinical trials,” he said. During mentioned that this concept using the immune system to target proteins in the brain may prove useful in treating other neurological disorders as well. “Our goal now is to broaden this to other models to show that it’s perhaps more a general phenomenon looking at Parkinson’s and other diseases in the brain,” he said. “But primarily, we’d like to move this to the clinic now. So we’re gearing up our research efforts to move toward a clinical trial.” NMDA is a receptor that responds to the chemical glutamate in the brain. The glutamate/NMDA complex is responsible for many normal brain functions like the development of neurons, learning and memory. Therefore, blocking the NMDA receptor in general could have damaging effects. However, the NMDA receptor is also involved in a chain of events that contribute to neurological damage from epilepsy, stroke and head injuries. Therefore, it is advantageous to block NMDA only during times of neurological insult.

To create the vaccine, the researchers added the gene that codes for the NMDA receptor to a virus. When this gene and virus combination enter the animal’s bloodstream, the immune system creates antibodies to both the virus and NMDA. These antibodies circulate in the blood, but are prevented from entering the brain by the blood brain barrier, a tightly packed group of cells that line blood vessels in the brain. The blood brain barrier is a protective mechanism that prevents many large molecules, such as these antibodies, from entering the brain. Yet during times of neurological insult, like epilepsy and stroke, the blood brain barrier is compromised, and the antibodies do enter the brain. They then seek out and block the NMDA receptor, preventing some brain damage from occurring. Soon afterwards, the blood brain barrier is restored, and the antibodies no longer have an effect on the brain.