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http://news.bbc.co.uk/2/hi/health/4699497.stm
Scientists have pinned down a reason why women are more vulnerable to coronary heart disease.
They have shown that a receptor for the female sex hormone oestrogen plays a key role.
They hope it may eventually be possible to produce therapies specifically targeted at women.
The research, by the University of Bonn, will be presented at meeting of the Federation of European Physiological Societies in Bristol.
With a more thorough understanding of sex difference in the maintenance of normal heart rhythm, we will be able to develop gender-specific therapies
Dr Andy James
It is widely accepted that men tend to get coronary heart disease at a younger age than women - but for women the condition tends to be more deadly.
Each year, over eight million women worldwide die from heart disease or strokes, the highest cause of death amongst women.
In developing countries, half of all deaths of women over 50 are due to heart disease and strokes.
Faulty rhythms
There are important differences between men and women in their chance of suffering potentially fatal disturbances to the normal heart rhythm (arrhythmias).
Arrhythmias are the result of disruption to the electrical properties of the heart.
The odds of disruption appear to higher if the length of time it takes the heart's electrical system to recharge following a heartbeat is longer rather than shorter.
This measurement is known as the QT interval - and tends to be longer in women.
Previously, this gender difference had been thought to be linked to effect of exposure to the male sex hormone testosterone.
Boys tend to adopt a typically masculine pattern of electrical activity in puberty, when testosterone levels are high, while cancer patients who have been castrated often revert to a feminine pattern of activity.
Female sex hormone
But the Bonn team has shown that an oestrogen receptor called ERalpha has a key influence on the electrical properties of the heart muscle.
Female mice who lacked the receptor in their heart muscle cells showed a pattern of electrical activity similar to that found in their male counterparts.
Dr Andy James, a lecturer in physiology at Bristol University, said: "This could help us understand the gender difference and how we can isolate and potentially minimise the risk to women.
"This is a departure from the currently well publicised but controversial suggestion that oestrogen protects women against heart disease.
"It is also suggests that the view that sex differences in risk of heart rhythm disturbance is all down to testosterone may be overly simplistic.
"With a more thorough understanding of sex difference in the maintenance of normal heart rhythm, we will be able to develop gender-specific therapies.
"We will be able to capitalise on the new understanding of the sex hormone function in the heart by producing medication that matches the different requirements currently faced by men and women."
Professor Jeremy Pearson, of the British Heart Foundation, told the BBC News website: "This work, examining the potential effect of oestrogen on the electrical activity of the heart, is one avenue of many helping us unravel the mystery of why women develop heart disease later than men.
"It is already believed that oestrogen receptors play a role in the known increased susceptibility of women to irregular heartbeat, so the main advance in this work is to nail down which receptor is responsible - at least in mice."
Scientists have pinned down a reason why women are more vulnerable to coronary heart disease.
They have shown that a receptor for the female sex hormone oestrogen plays a key role.
They hope it may eventually be possible to produce therapies specifically targeted at women.
The research, by the University of Bonn, will be presented at meeting of the Federation of European Physiological Societies in Bristol.
With a more thorough understanding of sex difference in the maintenance of normal heart rhythm, we will be able to develop gender-specific therapies
Dr Andy James
It is widely accepted that men tend to get coronary heart disease at a younger age than women - but for women the condition tends to be more deadly.
Each year, over eight million women worldwide die from heart disease or strokes, the highest cause of death amongst women.
In developing countries, half of all deaths of women over 50 are due to heart disease and strokes.
Faulty rhythms
There are important differences between men and women in their chance of suffering potentially fatal disturbances to the normal heart rhythm (arrhythmias).
Arrhythmias are the result of disruption to the electrical properties of the heart.
The odds of disruption appear to higher if the length of time it takes the heart's electrical system to recharge following a heartbeat is longer rather than shorter.
This measurement is known as the QT interval - and tends to be longer in women.
Previously, this gender difference had been thought to be linked to effect of exposure to the male sex hormone testosterone.
Boys tend to adopt a typically masculine pattern of electrical activity in puberty, when testosterone levels are high, while cancer patients who have been castrated often revert to a feminine pattern of activity.
Female sex hormone
But the Bonn team has shown that an oestrogen receptor called ERalpha has a key influence on the electrical properties of the heart muscle.
Female mice who lacked the receptor in their heart muscle cells showed a pattern of electrical activity similar to that found in their male counterparts.
Dr Andy James, a lecturer in physiology at Bristol University, said: "This could help us understand the gender difference and how we can isolate and potentially minimise the risk to women.
"This is a departure from the currently well publicised but controversial suggestion that oestrogen protects women against heart disease.
"It is also suggests that the view that sex differences in risk of heart rhythm disturbance is all down to testosterone may be overly simplistic.
"With a more thorough understanding of sex difference in the maintenance of normal heart rhythm, we will be able to develop gender-specific therapies.
"We will be able to capitalise on the new understanding of the sex hormone function in the heart by producing medication that matches the different requirements currently faced by men and women."
Professor Jeremy Pearson, of the British Heart Foundation, told the BBC News website: "This work, examining the potential effect of oestrogen on the electrical activity of the heart, is one avenue of many helping us unravel the mystery of why women develop heart disease later than men.
"It is already believed that oestrogen receptors play a role in the known increased susceptibility of women to irregular heartbeat, so the main advance in this work is to nail down which receptor is responsible - at least in mice."
