title: Nanometer-long Ge-imogolite nanotubes cause sustained lung inflammation and fibrosis in rats.
abstract: BACKGROUND
  Ge-imogolites are short aluminogermanate tubular nanomaterials with attractive prospected industrial applications. In view of their nano-scale dimensions and high aspect ratio, they should be examined for their potential to cause respiratory toxicity. Here, we evaluated the respiratory biopersistence and lung toxicity of 2 samples of nanometer-long Ge-imogolites.
  
  
  METHODS
  Rats were intra-tracheally instilled with single wall (SW, 70 nm length) or double wall (DW, 62 nm length) Ge-imogolites (0.02-2 mg/rat), as well as with crocidolite and the hard metal particles WC-Co, as positive controls. The biopersistence of Ge-imogolites and their localization in the lung were assessed by ICP-MS, X-ray fluorescence, absorption spectroscopy and computed micro-tomography. Acute inflammation and genotoxicity (micronuclei in isolated type II pneumocytes) was assessed 3 d post-exposure; chronic inflammation and fibrosis after 2 m.
  
  
  RESULTS
  Cytotoxic and inflammatory responses were shown in bronchoalveolar lavage 3 d after instillation with Ge-imogolites. Sixty days after exposure, a persistent dose-dependent inflammation was still observed. Total lung collagen, reflected by hydroxyproline lung content, was increased after SW and DW Ge-imogolites. Histology revealed lung fibre reorganization and accumulation in granulomas with epithelioid cells and foamy macrophages and thickening of the alveolar walls. Overall, the inflammatory and fibrotic responses induced by SW and DW Ge-imogolites were more severe (on a mass dose basis) than those induced by crocidolite. A persistent fraction of Ge-imogolites (15% of initial dose) was mostly detected as intact structures in rat lungs 2 m after instillation and was localized in fibrotic alveolar areas. In vivo induction of micronuclei was significantly increased 3 d after SW and DW Ge-imogolite instillation at non-inflammatory doses, indicating the contribution of primary genotoxicity.
  
  
  CONCLUSIONS
  We showed that nm-long Ge-imogolites persist in the lung and promote genotoxicity, sustained inflammation and fibrosis, indicating that short high aspect ratio nanomaterials should not be considered as innocuous materials. Our data also suggest that Ge-imogolite structure and external surface determine their toxic activity.
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. sybille.vandenbrule@uclouvain.be.
authors.forename: Sybille
authors.initials: S
authors.lastname: van den Brule
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. beckers.emilie@gmail.com.
authors.forename: Emilie
authors.initials: E
authors.lastname: Beckers
authors.affiliation: CEREGE, Aix Marseille Université, CNRS, IRD, UM34, UMR 7330, Europole de l'arbois - BP 80, 13545, Aix en Provence, France. chaurand@cerege.fr.|iCEINT, International Consortium for the Environmental Implications of Nanotechnology, CNRS, Duke University, 13545, Aix en Provence, France. chaurand@cerege.fr.
authors.forename: Perrine
authors.initials: P
authors.lastname: Chaurand
authors.affiliation: CEREGE, Aix Marseille Université, CNRS, IRD, UM34, UMR 7330, Europole de l'arbois - BP 80, 13545, Aix en Provence, France. liu@cerege.fr.|iCEINT, International Consortium for the Environmental Implications of Nanotechnology, CNRS, Duke University, 13545, Aix en Provence, France. liu@cerege.fr.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. saloua.ibouraadaten@uclouvain.be.
authors.forename: Saloua
authors.initials: S
authors.lastname: Ibouraadaten
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. mihaly.palmai@uclouvain.be.
authors.forename: Mihaly
authors.initials: M
authors.lastname: Palmai-Pallag
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. francine.uwambayinema@uclouvain.be.
authors.forename: Francine
authors.initials: F
authors.lastname: Uwambayinema
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. yousof.yakoub@uclouvain.be.
authors.forename: Yousof
authors.initials: Y
authors.lastname: Yakoub
authors.affiliation: CEREGE, Aix Marseille Université, CNRS, IRD, UM34, UMR 7330, Europole de l'arbois - BP 80, 13545, Aix en Provence, France. avellan@cerege.fr.|iCEINT, International Consortium for the Environmental Implications of Nanotechnology, CNRS, Duke University, 13545, Aix en Provence, France. avellan@cerege.fr.
authors.forename: Astrid
authors.initials: A
authors.lastname: Avellan
authors.affiliation: CEREGE, Aix Marseille Université, CNRS, IRD, UM34, UMR 7330, Europole de l'arbois - BP 80, 13545, Aix en Provence, France. levard@cerege.fr.|iCEINT, International Consortium for the Environmental Implications of Nanotechnology, CNRS, Duke University, 13545, Aix en Provence, France. levard@cerege.fr.
authors.forename: Clément
authors.initials: C
authors.lastname: Levard
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. vincent.haufroid@uclouvain.be.|Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Avenue Hippocrate 10, 1200, Brussels, Belgium. vincent.haufroid@uclouvain.be.
authors.forename: Vincent
authors.initials: V
authors.lastname: Haufroid
authors.affiliation: De Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75 - bte B1.75.02, 1200, Brussels, Belgium. etienne.marbaix@uclouvain.be.
authors.forename: Etienne
authors.initials: E
authors.lastname: Marbaix
authors.affiliation: Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire, CEA Saclay, 91191, Gif sur Yvette, France. antoine.thill@cea.fr.
authors.forename: Antoine
authors.initials: A
authors.lastname: Thill
authors.affiliation: Louvain centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium. dominique.lison@uclouvain.be.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lison
authors.affiliation: CEREGE, Aix Marseille Université, CNRS, IRD, UM34, UMR 7330, Europole de l'arbois - BP 80, 13545, Aix en Provence, France. rose@cerege.fr.|iCEINT, International Consortium for the Environmental Implications of Nanotechnology, CNRS, Duke University, 13545, Aix en Provence, France. rose@cerege.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Rose
mesh_terms: D000393:Air Pollutants / Q000737:chemistry / Q000633:toxicity; D000538:Aluminum Silicates / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D056809:Alveolar Epithelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D005857:Germanium / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D019570:Inhalation Exposure / Q000009:adverse effects*; D008168:Lung / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced; D043942:Nanotubes / Q000737:chemistry / Q000633:toxicity; D010316:Particle Size; D011014:Pneumonia / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000209:etiology*; D017208:Rats, Wistar; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D065589:Respiratory Tract Absorption; D014018:Tissue Distribution; D023382:Toxicity Tests, Acute; D066007:Toxicokinetics
chemical_list: D000393:Air Pollutants; D000538:Aluminum Silicates; D005857:Germanium