Hunger hormone ghrelin may improve heart function

Heart failure occurs when the heart cannot effectively pump blood throughout the body. This can lead to many problems, including fluid buildup and fatigue.

It can also lead to serious complications like kidney damage or sudden cardiac arrest.

Heart failure affects over 6 million adults in the United States alone. Certain factors can put someone at risk of developing the condition.

For example, people with coronary artery disease, diabetes, or high blood pressure are at a higher risk for heart failure. Lifestyle choices like low physical activity or a diet with a lot of sodium can also increase risk.

Management of heart failure involves a combined approach, often using medications and lifestyle changes.

Dr. Kulpreet Barn, cardiologist, and medical director of the Advanced Heart Failure Program at Deborah Heart and Lung Center, who was not involved in the current study, explained to Medical News Today:

“Left untreated, heart failure can be a lethal diagnosis. Depending on the stage of disease progression, there are multiple treatment options. Usually, patients are started with [medication], lifestyle changes, and controlling risk factors. If that does not work there are multiple devices to support the heart function, as the patient gets sicker. Once patients reach end-stage heart failure, they would need advanced heart failure therapies such as [a] left-ventricular assist device LVAD (a mechanical heart pump) or a heart transplant.”

Researchers of this study note that there are medications that increase the heart muscle’s ability to contract and increase cardiac output. Cardiac output is the amount of blood pumped out by the heart.

However, these medications can have adverse effects and are often only used in the short term.

Researchers wanted to see if ghrelin, a hormone that stimulates appetite, could effectively improve cardiac output. Researchers used an activated form of ghrelin, acyl ghrelin.

Study author Prof. Lars H. Lund, from the Department of Medicine at Solna, Karolinska Institute in Sweden, explained that the study’s goal was “[t]o test whether a novel drug treatment, acyl ghrelin, is safe and effective for patients with heart failure, and to test the mechanism of action in the laboratory.”

The study was a randomized, placebo-controlled, double-blind trial including about thirty participants with heart failure and reduced ejection fraction.

Ejection fraction has to do with the amount of blood the heart pumps to the body with each contraction. Researchers also looked at the effect of acyl ghrelin in the heart muscle cells of mice to look at the underlying mechanisms for the effects of acyl ghrelin.

The participants were divided either into the treatment group or the placebo group. The placebo group received an intravenous saline infusion, while the intervention group received synthetic human acyl ghrelin.

The infusions took place over 2 hours. In the intervention group, there was a great improvement in cardiac output. Researchers saw about a 28% increase in cardiac output without adverse effects.

Participants did not experience low blood pressure, high heart rate, ischemia, or abnormal heart rhythms. In the 2- to 5-day follow-up period, participants from the intervention group still saw a cardiac function level better than their baseline before treatment.

I​n studying mice’s heart muscle cells, researchers were able to look at some of the underlying mechanisms of acyl ghrelin effects.

While further research is needed, the lack of side effects of acyl ghrelin may have to do with a lack of mobilization of calcium ions.

The use of acyl ghrelin appears promising as a potential treatment option for people with heart failure.

Dr. Robert Segal, founder of Manhattan Cardiology, Board Certified Cardiologist, and a fellow of the American College of Cardiology (FACC), not involved in the study, noted to MNT:

“The observed clinical benefit of acylated (activated) ghrelin looks promising and based on the results, there is a reason for further clinical development. Treatment of heart failure due to reduced ejection fraction has always been a conundrum in medicine and hopefully, we can turn a corner with this devastating disease.”

T​his study had several limitations, so further research is warranted. First, the research only included a small number of participants and had a short follow-up time. So further research could consist of larger samples with a longer follow-up time frame.

In addition, because the investigation involved an endogenous peptide hormone, rather than a novel molecule or drug, there was no requirement for formal reporting of adverse events. However, the researchers monitored participants during and after receiving treatment.

The researchers note that their study did not determine the optimal dose of acyl ghrelin. Researchers also had certain limitations in assessing heart function, and there may have been some differences between the placebo and intervention groups.

Some of the study authors also reported potential conflicts of interest.

Further research is also needed to understand the underlying mechanism for the improvements researchers saw in cardiac function.

Prof. Lund noted that “[t]he present study provides a foundation for later phase trials of ghrelin-like treatments.”

He also added that future research could include “[a] larger clinical trial with longer treatment duration, to test whether this treatment may be effective for chronic use.”

D​r. Barn further commented that this was “a great, early-phase study that shows significant promise as there are positive improvements to the heart function.”

“Hopefully, this can translate into improvement for congestive heart failure patients. There would, however, need to be a larger randomized trial to see if these surrogate endpoints translate into clinical outcomes such as reducing mortality and hospitalization.”
— Dr. Kulpreet Barn