Two UTHCT researchers receive grants to study secondhand smoke, role of oxidants in protecting against inflammation

Friday, August 4, 2006

Two biomedical researchers at The University of Texas Health Science Center at Tyler recently received separate grants to study how secondhand smoke may make people more susceptible to tuberculosis infection and to examine the possible role of oxidants in protecting the body against the harmful effects of inflammation.

Amir Shams, Ph.D., an assistant professor of microbiology and immunology, received a $325,000, three-year grant from the Flight Attendants Medical Research Institute (FAMRI). He is investigating whether secondhand cigarette smoke makes individuals more susceptible to infection by the TB bacterium.

FAMRI sponsors scientific and medical research into the early detection, prevention, treatment, and cure of diseases and medical conditions caused by exposure to tobacco smoke.

Much research has been done on the effects of secondhand smoke on noninfectious diseases such as cancer and emphysema, Dr. Shams said. But researchers at UTHSCT are among the first to look into how secondhand smoke affects a person’s susceptibility to infectious diseases.

“We know that exposure to secondhand smoke can cause different kinds of lung diseases. We know that exposure to secondhand smoke reduces the immune response. So, it’s logical to think that it would make someone more susceptible to TB infection,” Dr. Shams said.

Dr. Shams and his team are investigating the mechanisms that enable secondhand smoke to weaken the immune response, thus making someone more likely to contract the disease.

“We hope to find the mechanisms that secondhand cigarette smoke triggers in those exposed to it. If we can find ways to reverse those mechanisms, it would help those people already exposed to secondhand smoke,” he said.

If Dr. Shams and his team succeed in identifying and understanding these mechanisms, their findings could be applied to other diseases affected by secondhand smoke. If their results are promising, Dr. Shams said he would seek future funding from entities such as the National Institutes of Health.

“The effect of secondhand smoke on people’s health is a big issue. I’m honored to be the third researcher at UTHSCT to receive a FAMRI grant,” he said.

Hua Tang, Ph.D., an assistant professor of biochemistry at UTHSCT, received a $130,000, two-year grant from the American Heart Association. He is studying oxidants, substances in the body that come from oxygen consumption and that are thought to contribute to inflammation, a major culprit in cardiovascular disease.

Inflammation is the body’s response to infection and injury. Evidence from lab research and clinical trials suggests that inflammation is a key player in the development of atherosclerosis, in which fatty deposits build up on the lining of arteries and cause heart attacks and strokes.

Dr. Tang and his team are investigating how a particular oxidant, hydrogen peroxide, is involved in the inflammation process. Oxidants are commonly thought to be harmful because they release free radicals, which have been shown to damage cells and perhaps accelerate the progression of cancer, cardiovascular disease, and age-related diseases.

“We are constantly producing oxidants in our cells. We expect antioxidants to improve the condition of the blood vessels and thus prevent or reduce the incidence of cardiovascular disease,” Dr. Tang said. Antioxidants are substances that block oxidation.

“However, it may be that oxidants don’t cause inflammation, but are byproducts of inflammation,” he said.

A large-scale study of controlled clinical trials failed to show any benefits from taking antioxidants, he said. Some study participants actually got worse.

“The results were disappointing. There’s no proof that antioxidants have any effect in reducing inflammation,” Dr. Tang said. It may be that the antioxidants were not delivered effectively or that the wrong antioxidant was used.

Now, Dr. Tang and his team are turning conventional wisdom on its head and proposing that lower doses of oxidants such as hydrogen peroxide may protect cells, not harm them. They are exploring how oxidants could control inflammation on the cellular level.

“Perhaps oxidants actually limit the spread of inflammation. They are very small molecules, and they may quickly diffuse among cells, protecting the body against inflammation,” Dr. Tang said.

“A healthy human body produces low doses of oxidants. If we can tolerate a non-toxic level of oxidants, that may benefit our cardiovascular system,” he said. There are scientific papers that suggest low doses of oxidants do have a protective effect, Dr. Tang said. For example, exercise generates low levels of oxidants, and drinking alcoholic beverages produces oxidants. Both exercising regularly and drinking alcohol in moderation have been shown to offer some protection against cardiovascular disease.

But no one has figured out how this process works on the cellular level, how small amounts of hydrogen peroxide could somehow inhibit inflammation. That’s what Dr. Tang and his team want to do.

“We are trying to understand the function of oxidants in the body. Is it necessary to remove oxidants from the body? We don’t know, and we don’t know which antioxidant works the best. The antioxidant story is not simple. It is very complicated,” Dr. Tang said.

If he and his team are successful, the payoff could be significant. His research could lead to new treatments for cardiovascular disease.

This is Dr. Tang’s second AHA grant. He has been involved in oxidation stress research funded by NIH for five years.

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