In vitro biologic responses to native and surface-modified asbestos

Our plain-English summary of In vitro biologic responses to native and surface-modified asbestos, by N. Hahon, V. Vallyathan, J.A. Booth, et al (Environmental Research, 1986).

The study

• Authors: N. Hahon, V. Vallyathan, J.A. Booth, M.J. Sepulveda
• Journal: Environmental Research
• Published: 1986;39(2):345-55
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A comparative study was made of in vitro biologic responses to native chrysotile, amosite, and crocidolite and corresponding asbestos fibers whose surfaces were modified by metal oxides. Interferon induction by influenza virus was depressed by approximately 50% by all native asbestos whereas corresponding surface modified asbestos minimally affected this nonspecific cellular defense mechanism. The release of the cytoplasmic enzyme, lactate dehydrogenase (LDH), and lysosomal enzymes, beta-N-acetylglucosaminidase (beta-NAG) and beta-glucuronidase (beta-Gluc), by rat alveolar macrophages after exposure to either native or surface-modified asbestos (which is indicative of membrane damage) was monitored. Although both native and surface-modified asbestos induced significant leakage of LDH, generally, lesser amounts of the enzyme were released as a result of exposure to the latter than to native asbestos. Whereas all forms of native asbestos caused significant release of beta-NAG and beta-Gluc, leakage of these enzymes from macrophages exposed to surface-modified asbestos was minimal. In contrast to native asbestos which induced irritation of cell membranes, as indicated by hemolysis of sheep erythrocytes, surface-modified asbestos exhibited minimal hemolytic activity. The findings indicate that surface modification of different asbestos by metal oxides generally lessened the adverse effect of the native mineral on the aforementioned biologic entities.

In plain English

This laboratory study compared cell responses to chrysotile (a short and an intermediate sample), amosite and crocidolite asbestos in natural ("native") form and after their surfaces were chemically modified with metal oxides by a patented process. The authors measured three things: interferon production (a natural antiviral defense) in monkey kidney cells, enzyme leakage from rat lung macrophages (a sign of membrane damage), and destruction of sheep red blood cells. Native fibers reduced interferon production by 44.6% to 59.5%, and modified fibers by 0.0% to 16.3%. Macrophages exposed to native fibers released 77.0% to 89.5% of the enzyme LDH, compared with 16.7% in untreated cells; with modified fibers the figure was 24.9% to 61.2%. Only native fibers caused significant leakage of two lysosomal enzymes. Native chrysotile destroyed 50 to 80% of red cells, and native amosite and crocidolite 35 to 45% at higher concentrations, versus 12% or less for modified fibers. The authors concluded that surface modification generally lessened the native fibers' adverse effects on these cells. They stated that further studies in cells and in living organisms were needed to establish conclusively whether surface modification limits the disease-causing potential of asbestos.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: in vitro (laboratory cell and tissue) comparative study
• Who was studied: Rhesus monkey kidney (LLC-MK2) cell monolayers for interferon tests; alveolar (lung) macrophages from male Sprague-Dawley rats for enzyme release tests; sheep red blood cells for hemolysis tests
• Exposure: Native and surface-modified (metal-micelle, treated with ammonium ferric sulfate) chrysotile (intermediate, Quebec, Canada), chrysotile (short, Diablo Range, California), amosite (Transvaal, South Africa) and crocidolite (Kalahari Desert, South Africa), supplied by the National Institute of Environmental Health Sciences. Doses: 1 mg fibers per cell monolayer for interferon tests; 1 mg/ml for 2 hours for macrophage tests; 1 to 5 mg for hemolysis tests
• Main results:
  • Native fibers inhibited viral interferon induction by about 50%: native amosite 55.4%, native chrysotile (interm) 44.6%, native chrysotile (short) 58.4%, native crocidolite 59.5%.
  • Surface-modified fibers caused minimal interferon inhibition: modified amosite 16.3%, modified chrysotile (interm) 0.0%, modified chrysotile (short) 6.5%, modified crocidolite 2.2%. All differences from the native forms were statistically significant.
  • LDH release from rat macrophages (mean percentage, plus or minus standard deviation): native amosite 89.5 ± 6.5, native crocidolite 88.1 ± 6.5, native chrysotile (interm) 81.6 ± 11.4, native chrysotile (short) 77.0 ± 14.3. Corresponding modified fibers gave 44.9 ± 7.1, 61.2 ± 11.1, 54.6 ± 13.1 and 24.9 ± 8.4. Untreated controls gave 16.7 ± 3.2. All fibers significantly increased LDH release except modified chrysotile (short).
  • All native asbestos forms caused significant release of the lysosomal enzymes beta-NAG and beta-Gluc from macrophages. Surface-modified asbestos did not cause significant leakage of these enzymes.
  • Hemolysis of sheep red blood cells: native chrysotile (short and intermediate) caused 50 to 80% hemolysis depending on concentration; both modified chrysotiles caused 10% or less.
  • Native amosite and crocidolite caused 35 to 45% hemolysis at higher concentrations; modified amosite and crocidolite caused 12% or less.
• The authors' conclusion: The authors concluded that surface modification of the different asbestos types by metal oxides generally lessened the adverse effects of the native mineral on the cells tested.
• Limitations the authors state:
  • The authors stated that further in vitro and in vivo studies are needed to establish conclusively whether surface modification limits the disease-causing potential of asbestos.
  • The authors noted that the mechanism by which surface-modified asbestos interacts with cell receptors is not known.
  • The authors noted that hemolysis by asbestos has not been conclusively demonstrated in living organisms.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Amosite, Chrysotile, Crocidolite.

Medical terms in this study, explained in our Lexicon: Chrysotile, Amosite, Crocidolite, Lactate Dehydrogenase (LDH), Alveolar Macrophage, Macrophage.

Related studies

• Coinhibition of viral interferon induction by benzo[a]pyrene and chrysotile asbestos — N. Hahon, J.A. Booth (1986)
• A reappraisal of the carcinogenicity of surface modified asbestos fibres — P. Carthew, R.E. Edwards, et al. (1993)
• Asbestos surface provides a niche for oxidative modification — H. Nagai, T. Ishihara, et al. (2011)
• Modification of the in vitro activities of amosite asbestos by surface derivatization — P.H. Evans, R.C. Brown, et al. (1983)
• Pulmonary cell interactions with asbestos fibers in vivo and in vitro — A.R. Brody (1986)
• Sorption of nonpolar aromatic contaminants by chlorosilane surface modified natural minerals — P. Huttenloch, K.E. Roehl, et al. (2001)

Browse more research in Environmental Research, or return to medical research.