Estrogen levels could explain why women are more likely to have irregular heartbeats.
- The team analyzed the type of ion channel most often mutated in long QT syndrome, named “Kv7.1/KCNE1”, by inserting its human variant and estradiol into frog eggs.
- Estrogen, secreted by the ovaries, interferes with the function of the ion channel. This impact seems to interact with the hereditary changes responsible for heart disease.
- “Certain mutations that reduce ion channel function appear to contribute to elevated estrogen sensitivity,” according to one author.
Estrogen, a hormone produced by the ovaries, has an impact on the regulation of heart rhythm. This was revealed by researchers from Linköping University in Sweden. To reach this conclusion, they carried out a study, the results of which were published in the journal Science Advances. Scientists have tried to understand which substances present in the body influence the function of ion channels, ie small pores that regulate the electrical activity of the heart and therefore the beat.
Heart rhythm disorders: why are women more affected?
As part of the work, the team looked at the possible effects of estrogen. They had this idea when asked by cardiologists why women were not only affected more often than men, but also more seriously affected by certain inherited diseases that cause abnormal heart rhythms.
To carry out their study, the authors looked at the type of ion channel most often mutated in long QT syndrome (an abnormality of the electrical system of the heart), which is called “Kv7.1/KCNE1”. As a reminder, in patients with this condition, the heart takes longer than normal to complete each beat.
According to them, the reduction of the function of this ionic channel is a factor which increases the risk of arrhythmia. To understand the impact of estrogen on this specific ion channel, researchers performed experiments in which they inserted the human variant of the ion channel into frog eggs that lack this ion channel. They added estradiol, the most active form of estrogen, and assessed ion channel function.
The effect of estrogen on the ion channel would contribute to the higher risk of arrhythmia
It turned out that the function of the ion channel was hampered by estrogen. According to scientists, the impact of this hormone seems to interact with the hereditary changes that cause heart disease, disrupting the rhythm of heartbeats. “We show that certain inherited mutations that reduce ion channel function appear to contribute to elevated estrogen sensitivity,” explained Sara Liin, author of the research, in a statement.
In their conclusions, the authors point out that it is important to remember the many positive effects of estrogen. In women with an increased hereditary risk of long QT syndrome, these hormones could potentially be a risk factor. This syndrome “is relatively rare, affecting approximately one in 2,500 people.”
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