Mini 'stress tests' could help condition heart to survive major attack

January 7, 2008

People who experience brief periods of blocked blood flow may be better conditioned to survive a full-blown heart attack later, according to new research from the University of Cincinnati (UC).

In a five-year laboratory study, UC surgeon-scientist Karyn Butler, MD, found that when the heart experiences short periods of stress, either from reduced blood flow or high blood pressure, it activates a protective molecular pathway—known as JAK-STAT—that protects the heart muscle. The pathway, which is normally dormant in the heart, was originally identified in disease-fighting white blood cells as a mediator of infection and has recently been targeted for its role in heart health.

Butler says when the JAK-STAT pathway is active and functioning, it can help precondition and protect the heart from damage caused when blood flow is restored after a period of decreased flow, as occurs after a heart attack.

“These mini stress tests appear to push the heart muscle into an adaptive state where it gets used to how long-term stress feels,” Butler explains. “This preconditioning helps the heart muscle better tolerate longer episodes of compromised blood flow.”

Her team reports their findings in the January 2008 issue of the American Journal of Physiology: Heart and Circulatory Physiology.

A trauma/critical care surgeon at University Hospital in Cincinnati, Butler wanted to determine how she could help patients with heart disease from high blood pressure tolerate cardiac ischemia, which occurs when vessels become narrowed or blocked and results in a dangerous reduction of blood flow to the heart.

To study the heart’s response to restored blood flow after cardiac ischemia and in the presence of hypertension, Butler developed a hypertrophied (enlarged) animal heart model to mimic the conditions of heart enlargement and congestive heart failure in humans.

The enlarged heart model was then subjected to preconditioning—a series of short periods of blood flow blockage—to simulate what happens in humans with serious heart disease.

Butler found that these mini stress tests activated the dormant JAK-STAT pathway, and helped protect the muscle from injury when blood flowed back into the heart.

“The concept is similar to how we approach a new physical fitness regimen: incremental steps. You wouldn’t try to condition yourself for a marathon by running 10 miles on your first day of training. You’d prepare yourself incrementally,” explains Butler, an associate professor of surgery at UC and corresponding author of the study.

“The body appears to be doing the same thing when it comes to the heart. Patients often endure short periods of reduced blood flow before the blockage causes irreversible cardiac damage,” she adds. “When the JAK-STAT pathway is activated, however, it appears to have a protective effect and may help the heart recover.”

By revealing the underlying molecular mechanisms, Butler says, scientists may be able to develop drugs designed to selectively harness the protective benefits of the JAK-STAT pathway and help patients avoid debilitating heart injuries.

Butler’s next step is to compare the effects of the JAK-STAT pathway in normal hearts with diseased hearts similar to those of patients at higher risk for heart attack.

Source: University of Cincinnati

Explore further: Understanding and preventing gangrene

Related Stories

Understanding and preventing gangrene

December 7, 2017
Dear Mayo Clinic: I have heard that a stubbed toe can lead to gangrene in some individuals. Is that true? What are the signs of gangrene, and how can it be avoided?

Children have strokes, too—new guidelines will help diagnosis

December 7, 2017
The country's first guidelines to improve doctors' ability to diagnose and manage stroke in children have been released today. Stroke is among the top ten causes of death in childhood and more than half of childhood stroke ...

Treatment of varicose veins

December 6, 2017
"Varicose veins" is a term commonly used to describe visible leg veins. But true varicose veins are dilated and very prominent. Small varicose veins may not be a problem, but as varicose veins worsen they become distended ...

Air pollution cancels positive health effects of exercise in older adults

December 5, 2017
Exposure to air pollution on city streets is enough to counter the beneficial health effects of exercise in adults over 60, according to a new study led by scientists at Imperial College London and Duke University.

Study links common male medical condition and vascular disease

December 1, 2017
Men who suffer symptoms from varicoceles, enlarged veins in the scrotum, are more likely to develop vascular disease and metabolic disease, such as diabetes, according to a study by Stanford University School of Medicine ...

For infants with heart disease, are shunts or stents better to maintain blood flow?

November 21, 2017
Infants with various forms of congenital heart disease require a stable source of blood flow to their lungs in order to survive until a more definitive operation can be performed. In a recent study, pediatric researchers ...

Recommended for you

Gene therapy improves immunity in babies with 'bubble boy' disease

December 9, 2017
Early evidence suggests that gene therapy developed at St. Jude Children's Research Hospital will lead to broad protection for infants with the devastating immune disorder X-linked severe combined immunodeficiency disorder. ...

In lab research, scientists slow progression of a fatal form of muscular dystrophy

December 8, 2017
In a paper published in the Nature journal Scientific Reports, Saint Louis University (SLU) researchers report that a new drug reduces fibrosis (scarring) and prevents loss of muscle function in an animal model of Duchenne ...

Double-blind study shows HIV vaccine not effective in viral suppression

December 7, 2017
(Medical Xpress)—A large team of researchers from the U.S. and Canada has conducted a randomized double-blind study of the effectiveness of an HIV vaccine and has found it to be ineffective in suppressing the virus. In ...

Time matters: Does our biological clock keep cancer at bay?

December 7, 2017
Our body has an internal biological or "circadian" clock, which cycles daily and is synchronized with solar time. New research done in mice suggests that it can help suppress cancer. The study, publishing 7 December in the ...

Novel harvesting method rapidly produces superior stem cells for transplantation

December 7, 2017
A new method of harvesting stem cells for bone marrow transplantation - developed by a team of investigators from the Massachusetts General Hospital (MGH) Cancer Center and the Harvard Stem Cell Institute - appears to accomplish ...

Inhibiting TOR boosts regenerative potential of adult tissues

December 7, 2017
Adult stem cells replenish dying cells and regenerate damaged tissues throughout our lifetime. We lose many of those stem cells, along with their regenerative capacity, as we age. Working in flies and mice, researchers at ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.