title: Single- and double-walled carbon nanotubes enhance atherosclerogenesis by promoting monocyte adhesion to endothelial cells and endothelial progenitor cell dysfunction.
abstract: The use of carbon nanotubes has increased lately. However, the cardiovascular effect of exposure to carbon nanotubes remains elusive. The present study investigated the effects of pulmonary exposure to single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) on atherosclerogenesis using normal human aortic endothelial cells (HAECs) and apolipoprotein E-deficient (ApoE-/-) mice, a model of human atherosclerosis.
  
  
  
  HAECs were cultured and exposed to SWCNTs or DWCNTs for 16 h. ApoE-/-mice were exposed to SWCNTs or DWCNTs (10 or 40 μg/mouse) once every other week for 10 weeks by pharyngeal aspiration.
  
  
  
  Exposure to CNTs increased the expression level of adhesion molecule (ICAM-1) and enhanced THP-1 monocyte adhesion to HAECs. ApoE-/-mice exposed to CNTs showed increased plaque area in the aorta by oil red O staining and up-regulation of ICAM-1 expression in the aorta, compared with vehicle-treated ApoE-/-mice. Endothelial progenitor cells (EPCs) are mobilized from the bone marrow into the circulation and subsequently migrate to the site of endothelial damage and repair. Exposure of ApoE-/-mice to high-dose SWCNTs or DWCNTs reduced the colony-forming units of EPCs in the bone marrow and diminished their migration function.
  
  
  
  The results suggested that SWCNTs and DWCNTs enhanced atherosclerogenesis by promoting monocyte adhesion to endothelial cells and inducing EPC dysfunction.
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Tada-Oikawa
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan.
authors.forename: Kiyora
authors.initials: K
authors.lastname: Izuoka
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Kataoka
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Ichikawa
authors.affiliation: Department of Occupational and Environmental Health, Nagoya Univeristy Graduate School of Medicine, Nagoya, Japan.
authors.forename: Wenting
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Occupational and Environmental Health, Nagoya Univeristy Graduate School of Medicine, Nagoya, Japan.
authors.forename: Cai
authors.initials: C
authors.lastname: Zong
authors.affiliation: Department of Occupational and Environmental Health, Tokyo Univeristy of Science, Noda, Japan.
authors.forename: Gaku
authors.initials: G
authors.lastname: Ichihara
authors.affiliation: Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho, Tsu, 514-8507, Japan. saho@gene.mie-u.ac.jp.
authors.forename: Sahoko
authors.initials: S
authors.lastname: Ichihara
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics; D050197:Atherosclerosis / Q000139:chemically induced*; D002448:Cell Adhesion / Q000187:drug effects*; D002478:Cells, Cultured; D066026:Endothelial Progenitor Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology*; D051379:Mice; D018345:Mice, Knockout; D046529:Microscopy, Electron, Transmission; D009000:Monocytes / Q000166:cytology*; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*
chemical_list: D001057:Apolipoproteins E; D037742:Nanotubes, Carbon
keywords: Adhesion; Atherosclerosis; Carbon nanotubes; Endothelial cells; Endothelial progenitor cells