Environmental factors and human health: fibrous and particulate substance-induced immunological disorders and construction of a health-promoting living environment

Our plain-English summary of Environmental factors and human health: fibrous and particulate substance-induced immunological disorders and construction of a health-promoting living environment, by T. Otsuki, H. Matsuzaki, S. Lee, et al (Environmental Health and Preventive Medicine, 2016).

The study

• Authors: T. Otsuki, H. Matsuzaki, S. Lee, N. Kumagai-Takei, S. Yamamoto, T. Hatayama, K. Yoshitome, Y. Nishimura
• Journal: Environmental Health and Preventive Medicine
• Published: 2016;21(2):71-81
• Type of article: Review
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Among the various scientific fields covered in the area of hygiene such as environmental medicine, epidemiology, public health and preventive medicine, we are investigating the immunological effects of fibrous and particulate substances in the environment and work surroundings, such as asbestos fibers and silica particles. In addition to these studies, we have attempted to construct health-promoting living conditions. Thus, in this review we will summarize our investigations regarding the (1) immunological effects of asbestos fibers, (2) immunological effects of silica particles, and (3) construction of a health-promoting living environment. This review article summarizes the 2014 Japanese Society for Hygiene (JSH) Award Lecture of the 85th Annual Meeting of the JSH entitled "Environmental health effects: immunological effects of fibrous and particulate matter and establishment of health-promoting environments" presented by the first author of this manuscript, Prof. Otsuki, Department of Hygiene, Kawasaki Medical School, Kurashiki, Japan, the recipient of the 2014 JSH award. The results of our experiments can be summarized as follows: (1) asbestos fibers reduce anti-tumor immunity, (2) silica particles chronically activate responder and regulatory T cells causing an unbalance of these two populations of T helper cells, which may contribute to the development of autoimmune disorders frequently complicating silicosis, and (3) living conditions to enhance natural killer cell activity were developed, which may promote the prevention of cancers and diminish symptoms of virus infections.

In plain English

This article was a review of the authors' own laboratory's earlier research, presented as a 2014 Japanese Society for Hygiene award lecture. For asbestos, they described a human T-cell line (MT-2). After more than 8 months of continuous exposure to chrysotile, it became resistant to asbestos-induced cell death and showed stronger suppressive function. These exposed cell lines, and helper T cells from patients with pleural plaque or malignant mesothelioma, showed reduced CXCR3 and a reduced capacity to make interferon-gamma. Chrysotile added to laboratory cultures reduced the development of cytotoxic T cells. Freshly isolated natural killer cells exposed to asbestos in the laboratory, and blood natural killer cells from patients, showed lower NKp46, an activating receptor. Among pleural plaque patients, some had levels similar to healthy volunteers and others had low levels. The authors suggested that plaque patients with low NKp46 may go on to develop mesothelioma, noting that close follow-up would be needed. They also reviewed silica work in silicosis patients, and indoor air dominated by negatively charged particles, which increased natural killer cell activity in healthy volunteers. The authors concluded that asbestos fibers reduce anti-tumor immunity in asbestos-exposed patients.

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: Review summarizing the authors' own previously published laboratory and clinical-sample studies (award lecture)
• Who was studied: Human cell lines (mainly the MT-2 T-cell line), blood cells from healthy volunteers, and samples from patients with pleural plaque, malignant mesothelioma or silicosis, in Japan. Numbers of patients are not given in this review. Healthy volunteers took part in the indoor-air experiments (60 per condition in the short-stay test, 15 in the 2-week test).
• Exposure: Laboratory exposure of cells to chrysotile (chrysotile A and chrysotile B) and crocidolite; asbestos exposure in pleural plaque and mesothelioma patients; silica particles; negatively charged particle-dominant indoor air
• Main results:
  • MT-2 T cells continuously exposed to chrysotile for more than 8 months became resistant to asbestos-induced cell death
  • The chrysotile-exposed subline CB1 showed stronger suppressive (regulatory T cell-like) function than the original cell line
  • Helper T cells from asbestos-exposed patients with pleural plaque and mesothelioma showed reduced CXCR3 and reduced capacity to express interferon-gamma
  • Adding chrysotile to a mixed lymphocyte culture suggested suppressed differentiation of cytotoxic T lymphocytes
  • Mesothelioma patients' blood CD8 lymphocytes showed impaired stimulation-induced cytotoxicity
  • In NK cell lines continuously exposed to asbestos, the activating receptors NKG2D and 2B4 were reduced
  • The NK cell activating receptor NKp46 was decreased in freshly isolated NK cells exposed to asbestos in the laboratory and in blood NK cells from pleural plaque and mesothelioma patients
  • Among pleural plaque patients, NKp46 levels fell into two groups: one similar to healthy volunteers (NKp46-high) and one with low expression (NKp46-low)
  • The authors speculated that many pleural plaque patients in the low NKp46 group will develop mesothelioma or other asbestos-induced cancers, pending follow-up
  • In silicosis patients, the regulatory T cell fraction showed reduced suppressive function
  • In healthy volunteers, a 2-week night stay in negatively charged particle-dominant rooms increased NK cell activity, and a 3-month home trial also showed enhanced NK activity
• The authors' conclusion: The authors concluded that asbestos fibers reduce anti-tumor immunity in asbestos-exposed patients. They stated they are trying to develop early diagnostic blood markers from these immune changes.
• Limitations the authors state:
  • Follow-up of pleural plaque patients is still needed to test whether low NKp46 predicts later cancer
  • Regulatory T cells could not be strictly defined by FoxP3 in the functional assay, so a broader cell fraction was used
  • The 2-week indoor-air experiment had a limited number of subjects, and changes varied between individuals

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Epidemiology, Silicosis.

Related studies

• Silica exposure and altered regulation of autoimmunity — S. Lee, H. Matsuzaki, et al. (2014)
• Search for biomarkers of asbestos exposure and asbestos-induced cancers in investigations of the immunological effects of asbestos — H. Matsuzaki, N. Kumagai-Takei, et al. (2017)
• Expression of the T cell receptor Vbeta repertoire in a human T cell resistant to asbestos-induced apoptosis and peripheral blood T cells from patients with silica and asbestos-related diseases — Y. Nishimura, Y. Miura, et al. (2006)
• Risk assessment due to environmental exposures to fibrous particulates associated with taconite ore — R. Wilson, E.E. McConnell, et al. (2008)
• Protest and survive, the U.K. Construction Safety Campaign: a case study of workers' and victims' family action and legal and regulatory inaction on construction health and safety — M. Holder, T. O'Brien (2007)
• Silicosis and autoimmunity — S. Lee, H. Hayashi, et al. (2017)

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