[ RadSafe ] "low dose radiation slows down cardiovascular disease"

[Franta, Jaroslav]

UNRESTRICTED | ILLIMITÉ

Interesting research suggesting radiation hormesis.....


Sent: February 17, 2011 8:34 AM
Subject: [cdn-nucl-l] Innovative radiobiology at Chalk River

FYI, this article was recently prepared by our biological research group at Chalk River Laboratories.  It’s a good example of the cutting-edge R&D that takes place here, with benefits for all Canadians.
Jeremy Whitlock
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In the Hearts of Mice and Men

The Biological Research Facility (BRF) at Chalk River Laboratories is a globally unique facility. Within the BRF, animal (rodent) and animal tissue-based research is undertaken to study the biological effects of radiation.

One project is a major, ongoing collaborative study that began in 2006 and is supported by the research program of the Commission of the European Union. AECL is one of many partners in this project, which includes 16 European universities and laboratories, McMaster University, Health Canada and the Ottawa Heart Institute.

One of the main objectives of our research is to determine the effects of low dose, gamma-radiation on the development and progression of cardiovascular disease (atherosclerosis) in mice. The mice used for heart research are genetically modified so that they will develop heart disease. Understanding what is happening in mice will increase our understanding of the consequences of exposure to low radiation doses in humans - such as doses commonly employed in diagnostic radiography and those incurred by radiation workers.

Atherosclerosis is a disease that is caused by the deposition of “fatty plaques” within arteries, including those in and around the heart. These plaques cause decreased blood flow to organs in the body, and angina in the heart. Also, they may block arteries causing heart attacks and strokes.

Mice were exposed either at early stages of the disease or at late stages of the disease to low doses of radiation. Different dose rates were used to reproduce both acute (short) and chronic (prolonged) irradiations.

At three months or six months post-exposure, the hearts and aortas of the mice were examined to determine the severity of the atherosclerotic lesions. Blood samples were also collected and tested for cholesterol levels. The atherosclerotic lesions were analyzed for size, severity and number.

While there were some differences between the effects produced by low and high dose rate exposures, and by exposures given at early and late stages of the disease, the effects seen were found to be generally protective, rather than damaging. Low doses of gamma-radiation resulted in fewer, smaller and less severe plaques. 

When higher doses of radiation were used these apparently beneficial effects disappeared and it is generally recognised that high radiation doses harm the heart and its arteries. How low dose radiation slows down cardiovascular disease is not yet clear, but it’s likely to be related to its anti-inflammatory effects.

An interesting consequence of this work is that the beneficial effects of low dose radiation on arteries, if confirmed in humans (and there is some evidence to suggest this may be so), may more than counter any shortened life expectancy from a small increased risk of cancer.

Nick Priest
Manager, Radiation Protection Research & Instrumentation        

Michelle Bugden
BRF Technologist       




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