Toxicity Testing

Researchers at Purdue University in Indiana have adapted a test used to measure the level of a toxin called acrolein in the bodies of cigarette smokers to measure the same toxin in people suffering from spinal cord injuries and degenerative diseases, such as multiple sclerosis (MS).

Acrolein is a toxin found in tobacco smoke and car exhaust, but it is also produced by the body in response to damage to nerve cells. The acrolein then causes a string of biochemical events thought to worsen the severity of the injury, whether it’s caused by trauma or disease.

According to the National Multiple Sclerosis Society (NMSS), MS is a chronic disease that occurs when the body's immune system attacks the protective coverings of nerve cells in the central nervous system, which is made up of the brain, spinal cord, and optic nerves. Symptoms of MS can range from mild numbness to blindness or complete paralysis. More than 400,000 people in the U.S. have MS, and worldwide, more than 1.2 million people suffer from it.

The bodies of MS patients produce acrolein in response to this damage to cells in the central nervous system. Acrolein is a volatile substance, and does not remain stable in the body long enough to measure. However, a byproduct of acrolein, known as 3-HPMA, is produced when acrolein breaks down and can be detected in the urine. 3-HPMA has successfully been used to measure acrolein levels in cigarette smokers, but until now, it has not been used to test levels of the chemical produced internally due to injury or degenerative disease.

Encouraging Test Results

Using this test on laboratory rats who were injected with various levels of acrolein, researchers were able to accurately measure differences in the concentration of 3-HPMA in the rats' urine.

"Nervous system trauma and diseases are like many other illnesses: A disease-associated marker can be critical for making a diagnosis, a therapeutic selection, and a treatment evaluation," said Riyi Shi, a professor of neuroscience and biomedical engineering in Purdue's Department of Basic Medical Sciences, School of Veterinary Medicine, Center for Paralysis Research, and Weldon School of Biomedical Engineering, in a press release. "Therefore, determination of acrolein levels gives you more assurance that you have an intense biochemical imbalance and biochemical damage and that you should use an acrolein scavenger as a treatment.”

There are two drugs already on the market that can effectively "scavenge" and eliminate acrolein in the body: hydralazine, which has been approved by the U.S. Food and Drug Administration (FDA) to treat hypertension, and phenelzine, which is FDA-approved to treat depression.

“We used different levels of hydralazine to see if it causes a dose-dependent reduction of 3-HPMA and found that, in fact, it did,” said Shi, “This shows that this method [of testing] is capable of monitoring the decrease of acrolein through treatment with acrolein-removing medications."

Besides spinal cord injuries and degenerative diseases, acrolein is thought to play a role in everything from stroke recovery to overcoming cancer. It may also exacerbate neurodegenerative diseases like Alzheimer’s.

Better Monitoring for MS Patients

Hydralazine, one of the acrolein-reducing drugs, has been shown to delay the onset of MS in laboratory animals by several days, which could equate to several years in humans. The drug has also been shown to reduce the severity of MS symptoms once the disease progresses.

For people with MS, this means that one day their doctor might routinely test their urine for acrolein and help them keep the toxin in check with drug therapy in order to reduce their MS symptoms.

Considering the results of this study, MS patients who also smoke may want to consider quitting. If both smoking and the MS disease process can increase acrolein levels, smokers with MS may be unwittingly contributing to the severity of their own symptoms.

For information about smoking cessation, visit the American Lung Association.

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