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Exposure to low-dose radiation may harm CV health

Ionizing radiation, even at low doses equivalent to repeated CT scans, significantly increases the risk for CV damage, according to data published in the International Journal of Radiation Biology.

“Epidemiological studies indicate that radiation doses as low as 0.5 Gy increase the risk of cardiovascular disease decades after the exposure,” Omid Azimzadeh, PhD, from the German Research Center for Environmental Health GmbH, and colleagues wrote.

“However, some studies find no significant risk at this radiation dose,” they added. “This raises the question about the nature of long-term alterations in the heart vasculature that could explain the discrepancy in the population-based data.”

Azimzadeh and colleagues evaluated if exposure to a relatively low radiation dose of 0.5 Gy (X-ray) triggers late molecular alterations in coronary artery endothelial cells. They used isotope-coded protein label technology to assess radiation-induced changes in the proteome after one, seven and 14 days. They validated significant changes that were identified by proteomics and bioinformatics through immunoblotting and ELISA.

The researchers found that the endothelial proteome sustained perturbation of Rho GDP-dissociation inhibitor and nitric oxide signaling pathways, indicating radiation-induced alteration. Reduced proteasome activity and enhanced protein carbonylation, suggesting augmented oxidative stress and senescence, was observed at later periods.

There were several radiation-induced long-term alterations, including activation of RhoA signaling and inhibition of eNOS activation, that may possibly adversely affect crucial endothelial functions, according to the researchers.

“This study shows that even a moderate radiation dose of 0.5 Gy has a significant adverse impact on the endothelial proteome,” Azimzadeh and colleagues concluded. “Molecular alterations seen here support the data from population studies suggesting an increased risk for cardiovascular disease after exposure to 0.5 Gy.”

“These molecular changes are indicative of long-term premature endothelial dysfunction and provide a mechanistic framework to the epidemiological data showing increased risk of cardiovascular disease at 0.5 Gy,” they added. – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.