They find new evidence of alcohol’s impact on the heart

Two new fundamental animal studies show Light on alcohol consumption and the heart. The first study may help explain why excessive alcohol consumption sometimes causes irregular heart rhythm and a possible way to prevent it. The second study looked at why alcohol might have negative impact on cardiac function in women taking estrogen replacement therapy. Both studies are preliminary studies of posters presented at the American Heart Association’s 2024 Scientific Sessions.

In the first case, the antiarrhythmic effects and novel mechanisms of Alda-1 in holiday heart syndrome are analyzed by Saugat Khanal, lead author of the study and a research fellow in the Department of Physiology and Cell Biology at the Ohio State University School of Medicine in Columbus, Ohio (USA).

Holidays provide opportunities for celebration, often accompanied by excessive alcohol consumption, over a short period of time. “Unfortunately, This sometimes results in revelers, even those with no previous heart problems, ending up in hospital with a racing or abnormal heartbeat. “Thus, our study in mice focused on the mechanism of alcohol-induced arrhythmia and a possible way to prevent it in the future,” the author explains.

“Repeated alcohol abuse can cause serious arrhythmias, such as atrial fibrillation, which is the most common type of arrhythmia. Atrial fibrillation can increase the risk of stroke and heart failure. About a third of new diagnoses of atrial fibrillation are associated with alcohol use. Recurrence of atrial fibrillation is common in heavy drinkers. “The relationship between repeated alcohol use and arrhythmia during the holidays is so well known that health professionals call it holiday heart syndrome, which is caused by repeated drinking during the holidays.”

Previous animal studies by this research group have shown that arrhythmias associated with excessive alcohol consumption are induced by an increase in a stress-induced protein called JNK2. This can cause heart cells to misuse calcium and fall apart. which causes the heart to beat too fast or irregularly. A new study suggests for the first time that a molecule called Alda-1 may prevent the activation of JNK2, which leads to atrial fibrillation.

In this study, more than 70% of mice exposed to alcohol to simulate heavy drinking developed atrial fibrillation, compared to none of those also exposed to the cardioprotective agent Alda-1. Exposure to heavy drinking levels doubled the level of JNK2 activity compared to controls that did not simulate heavy drinking. This activation of JNK2 increased susceptibility to atrial fibrillation in mice models that simulate heavy drinking. Both JNK2 enzyme activity and calcium handling remained normal in the hearts of mice exposed to Alda-1.

“Abstaining from alcohol can prevent most of the alcohol-related risks of atrial fibrillation. Unfortunately, despite national educational efforts, excessive alcohol consumption continues to increase among all age groups. Our results show that the development of new drugs

including Alda-1 and other specific JNK2 inhibitors, may be an effective strategy against atrial fibrillation for people with holiday heart syndrome, says Khanal.

On the other hand, a second study by Syed Anis Ahmed, a postdoctoral fellow in pharmacology and toxicology at the Brody School of Medicine at East Carolina University in Greenville, North Carolina (USA), analyzed the role of circadian period 2 and 2 and 10 days of ferroptosis in estrogen-deficient rats in estrogen modulation of ethanol-induced oxidative stress and cardiac dysfunction.

It should be taken into account that The hormone estrogen helps keep blood vessels open and flexible. and is generally thought to help protect women from heart disease. These higher estrogen levels may cause fewer heart attacks and strokes in premenopausal women than in men of the same age. However, alcohol exposure worsens cardiovascular function more in women than in men, the researchers say. What’s more, previous animal studies have shown that alcohol Cardiac function deteriorates further in those animals with the highest estrogen levels.

So the work focused on whether various measures of heart function and the proteins that regulate it differed with regular alcohol exposure in female rats given hormones to replenish estrogen stores and those that did not.

The eight-week study involved female rats that had had their ovaries removed to simulate menopause (when the ovaries produce little to no estrogen). The researchers compared menopausal rats that were regularly exposed to alcohol (5% ethanol in a liquid diet) with rats that were given alcohol and estrogen replacement therapy.

The study found that, compared with those given alcohol alone, menopausal rats given estrogen replacement therapy plus alcohol had both positive (less weight gain and fat mass) and negative (higher blood pressure and heart rate) changes in markers related to heart health; a decrease in cardiac ejection fraction, the heart’s ability to pump oxygen-rich blood to the rest of the body, and two other markers of poor blood pumping that can eventually lead to heart failure; and

On the other side, alteration of circadian clock proteins, which are known to regulate heart function and other processes in the body, increase both oxidative stress (which can cause plaque buildup in arteries) and ferroptosis (a type of cell death that results from excess iron) in heart cells.

“It was surprising to see a significant effect of estrogen on alcohol-induced cardiac dysfunction despite its known cardioprotective effects. Premenopausal and menopausal women taking hormone replacement therapy should be careful with alcohol consumption as it may be a factor in cardiac dysfunction,” concludes Syed Anis Ahmed.