title: Modest vasomotor dysfunction induced by low doses of C60 fullerenes in apolipoprotein E knockout mice with different degree of atherosclerosis.
abstract: BACKGROUND
  Exposure to small size particulate matter in urban air is regarded as a risk factor for cardiovascular effects, whereas there is little information about the impact on the cardiovascular system by exposure to pure carbonaceous materials in the nano-size range. C60 fullerenes are nano-sized particles that are expected to have a widespread use, including cosmetics and medicines.
  
  
  METHODS
  We investigated the association between intraperitoneal injection of pristine C60 fullerenes and vasomotor dysfunction in the aorta of 11-13 and 40-42 weeks old apolipoprotein E knockout mice (apoE-/-) with different degree of atherosclerosis.
  
  
  RESULTS
  The aged apoE-/-mice had lower endothelium-dependent vasorelaxation elicited by acetylcholine in aorta segments mounted in myographs and the phenylephrine-dependent vasoconstriction response was increased. One hour after an intraperitoneal injection of 0.05 or 0.5 mg/kg of C60 fullerenes, the young apoE-/- mice had slightly reduced maximal endothelium-dependent vasorelaxation. A similar tendency was observed in the old apoE-/- mice. Hampered endothelium-independent vasorelaxation was also observed as slightly increased EC50 of sodium nitroprusside-induced vasorelaxation response in young apoE-/- mice.
  
  
  CONCLUSIONS
  Treatment with C60 fullerenes affected mainly the response to vasorelaxation in young apoE-/- mice, whereas the vasomotor dysfunction in old apoE-/- mice with more advanced atherosclerosis was less affected by acute C60 fullerene treatment. These findings represent an important step in the hazard characterization of C60 fullerenes by showing that intraperitoneal administration is associated with a moderate decrease in the vascular function of mice with atherosclerosis.
authors.affiliation: Department of Public Health, Section of Environment Health, University of Copenhagen, Øster Farimagsgade 5A, DK-1014 Copenhagen K, Denmark. pemo@pubhealth.ku.dk.
authors.forename: Lise K
authors.initials: LK
authors.lastname: Vesterdal
authors.forename: Janne K
authors.initials: JK
authors.lastname: Folkmann
authors.forename: Nicklas R
authors.initials: NR
authors.lastname: Jacobsen
authors.forename: Majid
authors.initials: M
authors.lastname: Sheykhzade
authors.forename: Håkan
authors.initials: H
authors.lastname: Wallin
authors.forename: Steffen
authors.initials: S
authors.lastname: Loft
authors.forename: Peter
authors.initials: P
authors.lastname: Møller