Radiation-induced apoptosis varies among individuals and is modified by sex and age

Mark A Applebaum, Andrew D Skol, Elisabeth E Bond, Michael Overholtzer, Gareth L Bond, Kenan Onel

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


PURPOSE: 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.

MATERIALS AND METHODS: 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.

RESULTS: 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%; p < 3.5 × 10(-7)). Moreover, advancing age was associated with decreasing radiation-induced apoptosis in males (p = 0.01) but not females (p = 0.82).

CONCLUSIONS: 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.

Original languageEnglish
Pages (from-to)903-908
Number of pages6
JournalInternational Journal of Radiation Biology
Issue number10
Early online date25 Jun 2014
Publication statusPublished - Oct 2014


  • Adult
  • Aging/physiology
  • Apoptosis/physiology
  • Cells, Cultured
  • Computer Simulation
  • Female
  • Humans
  • Leukocytes, Mononuclear/cytology
  • Male
  • Middle Aged
  • Models, Biological
  • Radiation Dosage
  • Reference Values
  • Sex Factors
  • Young Adult
  • Ionizing radiation
  • models of cell killing
  • human cells
  • age
  • apoptosis


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