Radiation-induced apoptosis varies among individuals and is modified by sex and age. (October 2014)

• Record Type: Journal Article
• Authors: Applebaum, Mark A.; Skol, Andrew D.; Bond, Elisabeth E.; Overholtzer, Michael; Bond, Gareth L.; Onel, Kenan
• Is Part Of: International journal of radiation biology. Volume 90:Number 10(2014:Oct.)
• Page Start: 903
• Page End: 908
• Publication Date: 2014-10
• Subjects: Radiation -- Physiological effect -- Periodicals; Radiobiology -- Periodicals; 571.45
• DOI: 10.3109/09553002.2014.925603
• Languages: English
• ISSNs: 0955-3002

Abstract

<abstract> <title>Abstract</title> <p> <italic>Purpose</italic>: Although there are considerable data on mechanisms of radiation-induced apoptosis in vitro and in animal models, little is known about functional variation in these pathways in humans. We sought to develop a tractable system to evaluate this.</p> <p> <italic>Materials and methods</italic>: Peripheral blood mononuclear cells were isolated from 90 healthy volunteers, divided into two aliquots, one irradiated with a 5 Gy dose and the other sham-treated (0 Gy), and assessed for damage-induced apoptosis after 24 hours. To investigate reproducibility, 10 individuals spanning the entire radiation-induced apoptotic range were tested three times each, with 3–6 months between replicates.</p> <p> <italic>Results</italic>: We observed surprising heterogeneity in apoptosis among individuals, ranging from 21–62%. Biological replicates from a single individual, however, were completely concordant, suggesting the variability observed across individuals is not the result of stochastic or short-term effects. We found significantly higher radiation-induced apoptosis in males than in females (Mean: 41.0% vs. 30.7%; <italic>p</italic> < 3.5 × 10<sup>−7</sup>). Moreover, advancing age was associated with decreasing radiation-induced apoptosis in males (<italic>p = </italic>0.01) but not females (<italic>p = </italic>0.82).</p> <p> <italic>Conclusions</italic>: Our results provide evidence that the function of cellular pathways crucial for stress-induced apoptosis varies by sex and could decline with age in humans.</p> </abstract>