title: Irradiation in presence of iodinated contrast agent results in radiosensitization of endothelial cells: consequences for computed tomography therapy.
abstract: OBJECTIVE
  To date, iodinated contrast agents (ICA) are commonly used in medical imaging to improve tumor visualization by attenuating scanners X-rays. However, some adverse reactions to ICAs are still reported, and their molecular origin remains unclear. In 1983, it was proposed to visualize and treat ICA-loaded tumors by using scanners as therapy machines to enhance X-rays absorption at the iodine atoms. Theoretically, such physical conditions are optimized at 50 keV and can be easily obtained with synchrotrons.
  
  
  METHODS
  Here, we examined the molecular and cellular responses of mammalian endothelial cells to radiation in the presence of iomeprol, one of the most extensively used ICAs.
  
  
  RESULTS
  Irradiation with X-rays at 50 keV in the presence of iomeprol produced a strong radiosensitization effect. The same conclusion was reached with a standard medical irradiator but to a lesser extent. While such treatment did not produce additional DNA double-strand breaks, we observed a dose-dependent production of iodides due to the iomeprol radiolysis that inhibit double-strand break repair rate by decreasing DNA-PK kinase activity.
  
  
  CONCLUSIONS
  Our data suggest that the concomitant use of ICA and radiation may be toxic when radiation-produced iodide concentrations and double-strand break yields are sufficient. The potential toxicity of ICAs during X-rays for diagnosis and therapy is discussed.
authors: Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, France.
authors: Aurélie
authors: A
authors: Joubert
authors: Marie-Claude
authors: MC
authors: Biston
authors: Caroline
authors: C
authors: Boudou
authors: Jean-Luc
authors: JL
authors: Ravanat
authors: Thierry
authors: T
authors: Brochard
authors: Anne-Marie
authors: AM
authors: Charvet
authors: François
authors: F
authors: Estève
authors: Jacques
authors: J
authors: Balosso
authors: Nicolas
authors: N
authors: Foray
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003287:Contrast Media / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000528:radiation effects*; D007479:Iopamidol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011836:Radiation Tolerance / Q000187:drug effects* / Q000502:physiology; D017356:Synchrotrons
chemical_list: D003287:Contrast Media; D004268:DNA-Binding Proteins; C057937:iomeprol; D004247:DNA; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D007479:Iopamidol