Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Estrogens as antioxidants - reducing heart disease in younger postmenopausal women

07.07.2003


HRT could be used to protect younger postmenopausal women from heart disease. An article published in the journal Lipids in Health and Disease shows that estrogens commonly used in HRT reduce the build up of harmful oxidised lipoproteins, which can lead to heart disease, by acting as antioxidants.



It is well known that high-density lipoproteins (HDL) protect against heart disease while low-density lipoproteins (LDL) promote it. However, recent research has shown that the relationship is not that simple. The effectiveness of both types of lipoprotein change when they are oxidised by free radicals – highly reactive by-products of metabolism. If LDL becomes oxidised its ability to cause heart disease increases. If HDL becomes oxidised its ability to protect against heart disease is lessened.

Researchers from St. Michael’s Hospital, part of the University of Toronto, have shown that estrogens can act as antioxidants, which neutralise free radicals, and hence protect HDL from oxidation. In addition, high levels of HDL are able to protect LDL from oxidation, and this ability is strongly enhanced when estrogens are present.


Dr Bhagu Bhavnani’s team, who carried out the research, write, “The inhibition of HDL oxidation and the enhancement provided by estrogens toward the inhibition of LDL oxidation may be another way in which estrogens reduce the risk of coronary heart disease in healthy young postmenopausal women.”

Although recent randomised control trials have shown that HRT in older women may not reduce the incidence of coronary heart disease, Dr. Bhavnani believes that this is not the whole story. Although his team carried out experiments in test tubes rather than in human subjects they saw that estrogen had beneficial effects at concentrations lower than those found in women on HRT. He urges that, “randomised control trials using lower doses of HRT, different estrogens and progestins, and in younger postmenopausal women, from 50 to 60 years, are urgently needed to resolve the confusion created by recent studies”.

The research team used blood taken from men and postmenopausal women to carry out experiments in vitro. They measured the resistance of HDL to oxidation in the presence or absence of increasing concentrations of eleven different estrogens. All of these estrogens are components of a combined estrogen supplement that is commonly used for HRT by postmenopausal women. They then assessed whether the presence of HDL increased the resistance of LDL to oxidation, and if this resistance was further enhanced by the addition of estrogen.

They found that all the estrogens tested were able to protect HDL from oxidation and to enhance HDL’s ability to protect LDL from oxidation. They also found that different estrogens had different potencies as antioxidants, with an estrogen called Equilenin being the most effective.

According to recent data from the British Heart Foundation, women are five times less likely to suffer from coronary heart disease than men. This reduced risk can only partly be explained by differences in behaviour, such as smoking or stress levels. As women’s risk of heart disease increases after menopause it has been suggested that ovarian hormones such as estrogen play a role in protecting younger women from the disease. The research from Bhavnani’s team supports this idea.

Gemma Bradley | BioMed Central
Further information:
http://www.biomedcentral.com
http://www.lipidworld.com/content/2/1/4

More articles from Health and Medicine:

nachricht New vaccine production could improve flu shot accuracy
25.07.2017 | Duke University

nachricht Chances to treat childhood dementia
24.07.2017 | Julius-Maximilians-Universität Würzburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>