Pleural translocation and lesions by pulmonary exposed multi-walled carbon nanotubes

Our plain-English summary of Pleural translocation and lesions by pulmonary exposed multi-walled carbon nanotubes, by Q. Wang, Q. Wang, Z. Zhao, et al (Journal of Toxicologic Pathology, 2020).

The study

• Authors: Q. Wang, Q. Wang, Z. Zhao, D.B. Alexander, D. Zhao, J. Xu, H. Tsuda
• Journal: Journal of Toxicologic Pathology
• Published: 2020;33(3):145-151
• Type of article: Review
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Carbon nanotubes (CNTs) are recently developed tubular nanomaterials, with diameters ranging from a few nanometers to tens of nanometers, and the length reaching up to several micrometers. They can be either single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs). Due to their nano-scaled structure, CNTs have a unique set of mechanical, electrical, and chemical properties that make them useful in information technologies, optoelectronics, energy technologies, material sciences, medical technologies, and other fields. However, with the wide application and increasing production of CNTs, their potential risks have led to concerns regarding their impact on environment and health. The shape of some types of CNTs is similar to asbestos fibers, which suggests that these CNTs may cause characteristic pleural diseases similar to those found in asbestos-exposed humans, such as pleural plaques and malignant mesothelioma. Experimental data indicate that CNTs can induce lung and pleural lesions, inflammation, pleural fibrosis, lung tumors, and malignant mesothelioma upon inhalation in the experimental animals. In this review, we focus on the potential of MWCNTs to induce diseases similar to those by asbestos, molecular and cellular mechanisms associated with these diseases, and we discuss a method for evaluating the pleural toxicity of MWCNTs.

©2020 The Japanese Society of Toxicologic Pathology.

In plain English

This article is a review, not a new study. The authors summarized earlier laboratory and animal research, including some of their own, on whether multi-walled carbon nanotubes (MWCNTs) can move from the lungs into the pleural cavity and damage the pleura. Some MWCNTs have a needle-like shape similar to asbestos fibers. Cited studies found that MWCNTs sprayed into the lungs of test animals reached the pleural cavity, though only a small proportion did. There they caused inflammation, fibrosis and growth of mesothelial cells. In one cited 2-year study, 15.8% of rats given MWCNTs into the lungs for 2 weeks developed malignant mesothelioma in the pleural cavity. Cited work also reported that short, tangled MWCNTs did not cause pleural fibrosis. The authors described a pleural cavity lavage method they had developed for assessing pleural toxicity. They noted that similar respiratory toxicity in humans had not been reported and that no uniform standard method exists. They concluded that MWCNTs, like asbestos, have the potential to cause pleural lesions including malignant mesothelioma, and they called for strict control of their production and use.

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: Narrative review of in vitro and animal studies on pleural translocation and pleural lesions caused by multi-walled carbon nanotubes
• Who was studied: Studies reviewed were mainly in vitro cell studies and rodent (rat and mouse) experiments; no new population was studied
• Exposure: Multi-walled carbon nanotubes (MWCNTs), given mainly by intratracheal spraying into the lungs in the reviewed studies, and also by injection into the peritoneal cavity or scrotum; no asbestos exposure was studied
• Main results:
  • Cited studies found that MWCNTs sprayed into the lungs of test animals translocated to the pleural cavity, but the proportion that translocated was small
  • In one cited 2-year study, 15.8% of Fisher rats given MWCNTs intratracheally for 2 weeks at the start developed malignant mesothelioma in the pleural cavity (the number of rats is not given in this review)
  • In a cited study, injecting different types of MWCNT at different doses into the peritoneal cavity led to malignant mesothelioma in all cases
  • Cited work reported that short tangled MWCNTs did not cause pleural fibrosis, and the authors stated that pleural lesions depend on MWCNT length and rigidity
  • In rats given MWCNTs intratracheally for 2 weeks, a cited study reported that the fibers could still be detected in the pleura 3 months later
  • A cited study found that approximately 80% of the infiltrating cells in the pleural cavity of MWCNT-treated animals were CD68-positive cells (macrophages)
• The authors' conclusion: The authors concluded that in vitro and animal studies suggest MWCNTs, like asbestos fibers, have the potential to induce pleural lesions such as chronic inflammation, fibrosis and malignant mesothelioma. They stated that production and use of MWCNTs and other fibrous materials should be strictly controlled.
• Limitations the authors state:
  • Similar respiratory toxicity of carbon nanotubes in humans has not been reported
  • There is no uniform standard method to evaluate the pleural toxicity of inhaled material
  • How MWCNTs travel from the lungs to the pleura is still unclear
  • The fiber length threshold for pleural effects has not been determined

Topics

Medical terms in this study, explained in our Lexicon: Pleural Translocation, Pleural Plaques, Malignant Mesothelioma, Inflammation, Fibrosis.

Related studies

• Multi-walled carbon nanotubes translocate into the pleural cavity and induce visceral mesothelial proliferation in rats — J. Xu, M. Futakuchi, et al. (2012)
• Comparative carcinogenicity study of a thick, straight-type and a thin, tangled-type multi-walled carbon nanotube administered by intra-tracheal instillation in the rat — D.M. Saleh, W.T. Alexander, et al. (2020)
• Persistent Pleural Lesions and Inflammation by Pulmonary Exposure of Multiwalled Carbon Nanotubes — D. Liao, Q. Wang, et al. (2018)
• Long-term pulmonary exposure to multi-walled carbon nanotubes promotes breast cancer metastatic cascades — X. Lu, Y. Zhu, et al. (2019)
• Epithelial-mesenchymal transition involved in pulmonary fibrosis induced by multi-walled carbon nanotubes via TGF-beta/Smad signaling pathway — T. Chen, H. Nie, et al. (2014)
• Novel method using hybrid markers: development of an approach for pulmonary measurement of multi-walled carbon nanotubes — M. Ohnishi, H. Yajima, et al. (2013)

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