Assessment of the pathogenic potential of asbestiform vs. nonasbestiform particulates (cleavage fragments) in in vitro (cell or organ culture) models and bioassays

Regul Toxicol Pharmacol. 2008 Oct;52(1 Suppl):S200-3. doi: 10.1016/j.yrtph.2007.10.004. Epub 2007 Oct 11.


Asbestos fibers are highly fibrous silicate fibers that are distinguished by having a large aspect (length to diameter) ratio and are crystallized in an asbestiform habit that causes them to separate into very thin fibers or fibrils. These fibers are distinct from nonasbestiform cleavage fragments and may appear as thick, short fibers which break along cleavage planes without the high strength and flexibility of asbestiform fibers. Since cleavage fragments of respirable dimensions have generally proven nonpathogenic in animal studies, little data exists on assessing well-characterized preparations of cleavage fragments in in vitro models. The available studies show that cleavage fragments are less bioreactive and cytotoxic than asbestiform fibers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Asbestos / classification
  • Asbestos / toxicity*
  • Biological Assay*
  • Carcinogens, Environmental / classification
  • Carcinogens, Environmental / toxicity*
  • Cell Survival / drug effects
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Humans
  • Lung / cytology
  • Lung / drug effects
  • Mineral Fibers / classification
  • Mineral Fibers / toxicity
  • Organ Culture Techniques
  • Particle Size
  • Pleura / cytology
  • Pleura / drug effects
  • Trachea / cytology
  • Trachea / drug effects


  • Carcinogens, Environmental
  • Mineral Fibers
  • Asbestos