April 01, 2016

SLU Scientists Ask if Smoking Takes Toll on Ticker

Researchers examine human heart tissue to gauge smoking’s damage

Jane McHowat, Ph.D., professor of pathology at SLU

ST. LOUIS — With the help of a new award from the Lottie Caroline Hardy Charitable Trust, SLU scientist Jane McHowat, Ph.D., will study how smoking impacts cardiac health beyond injury to the body’s arteries by damaging the heart muscle itself.

McHowat, professor of pathology at Saint Louis University, will use the $21,643 grant to study human tissue samples from the myocardium, the muscular wall of the heart.

Doctors know that smoking is a major risk factor for cardiovascular disease, including atherosclerosis, hypertension, myocardial infarction, sudden cardiac death and stroke. However, the mechanisms behind the smoking-heart health connection remain murky.

While many researchers have examined smoking’s impact on the arteries that supply blood to the heart, very few have studied smoking’s effects on the heart muscle itself.

In order to learn whether smoking hurts the heart, McHowat is partnering with Dawn Hui, M.D., and Richard Lee, M.D., from the Center for Comprehensive Cardiovascular Care at SSM Health Saint Louis University Hospital.

Hui and Lee, who are also SLUCare cardiac surgeons, will save samples from patients undergoing cardiac surgery. Outside of procedures like bypass surgery, it is impossible to gather fresh samples of human heart tissue without an invasive procedure.

Once the samples are collected, the research team will determine if there are differences between the heart samples from smokers and non-smokers.

In past research, McHowat has shown that that an enzyme responsible for PAF (platelet activating factor) is reduced by smoking, leading to PAF build-up. This, in turn, leads to lower levels of PEDF (pigment epithelium-derived factor), a protein that limits cell damage through its antioxidative and anti-inflammatory properties.

McHowat’s theory is that increased PAF accumulation and decreased PEDF activity in the myocardium may predispose smokers to increased damage to the heart, resulting in impaired cardiac function.

“Some initial studies suggest that this is what may be happening,” McHowat said. “In this study we’re going to examine the patient samples, look for changes in the structure and chemistry of the heart, and then see what differences appear between samples from smoking and non-smoking patients.”

If the study shows that the heart muscle is indeed damaged by smoking, it will add to the mountains of evidence that smoking is deeply damaging to our health. It also might provide targets for future drug development designed to treat heart issues.

“It may be that those who smoke and then suffer a heart attack can’t recover as well and may lose more function.

“This area of study has a lot of unanswered questions,” McHowat said. “We’re hoping to answer some of them.”

Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first medical degree west of the Mississippi River. The school educates physicians and biomedical scientists, conducts medical research, and provides health care on a local, national and international level. Research at the school seeks new cures and treatments in five key areas: cancer, liver disease, heart/lung disease, aging and brain disease, and infectious diseases.

Established by Lottie Caroline Hardy at the time of her death from brain cancer in 1979, the Lottie Caroline Hardy Charitable Trust provides funding for the benefit and research into the cause and cure of cancer, heart disease, arthritis and emphysema.

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