Sulfur mustard (SM) is a frequently used chemical warfare agent, even in modern history. SM inhalation causes significant respiratory tract injury, with early complications due to airway obstructive bronchial casts, akin to those seen after smoke inhalation and in single-ventricle physiology. This process with SM is poorly understood because animal models are unavailable.
To develop a rat inhalation model for airway obstruction with the SM analog 2-chloroethyl ethyl sulfide (CEES), and to investigate the pathogenesis of bronchial cast formation.
Adult rats were exposed to 0, 5, or 7.5% CEES in ethanol via nose-only aerosol inhalation (15 min). Airway microdissection and confocal microscopy were used to assess cast formation (4 and 18 h after exposure). Bronchoalveolar lavage fluid (BALF) retrieval and intravascular dye injection were done to evaluate vascular permeability.
Bronchial casts, composed of abundant fibrin and lacking mucus, occluded dependent lobar bronchi within 18 hours of CEES exposure. BALF contained elevated concentrations of IgM, protein, and fibrin. Accumulation of fibrin-rich fluid in peribronchovascular regions (4 h) preceded cast formation. Monastral blue dye leakage identified bronchial vessels as the site of leakage.
After CEES inhalation, increased permeability from damaged bronchial vessels underlying damaged airway epithelium leads to the appearance of plasma proteins in both peribronchovascular regions and BALF. The subsequent formation of fibrin-rich casts within the airways then leads to airways obstruction, causing significant morbidity and mortality acutely after exposure.
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[Show abstract][Hide abstract]ABSTRACT: The continuing horrors of military conflicts and terrorism often involve the use of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs). Many CWA and TIC exposures are difficult to treat due to the danger they pose to first responders and their rapid onset that can produce death shortly after exposure. While the specific mechanism(s) of toxicity of these agents are diverse, many are associated either directly or indirectly with increased oxidative stress in affected tissues. This has led to the exploration of various antioxidants as potential medical countermeasures for CWA/TIC exposures. Studies have been performed across a wide array of agents, model organisms, exposure systems, and antioxidants, looking at an almost equally diverse set of endpoints. Attempts at treating CWAs/TICs with antioxidants have met with mixed results, ranging from no effect to nearly complete protection. The aim of this commentary is to summarize the literature in each category for evidence of oxidative stress and antioxidant efficacy against CWAs and TICs. While there is great disparity in the data concerning methods, models, and remedies, the outlook on antioxidants as medical countermeasures for CWA/TIC management appears promising.
Full-text · Article · Oct 2015 · Biochemical pharmacology
"To test this hypothesis, a TRPA1-expressing HEK293 cell line and the alkylating agent 2-chloroethyl- ethylsulfide (CEES) were used. The monoalkylating agent CEES was used as a well-established surrogate for SM (Veress et al. 2010), while proof-of-concept experiments using SM and lung epithelial cells were also conducted. "
[Show abstract][Hide abstract]ABSTRACT: The transient receptor potential ankyrin 1 (TRPA1) cation channel is expressed in different tissues including skin, lung and neuronal tissue. Recent reports identified TRPA1 as a sensor for noxious substances, implicating a functional role in the molecular toxicology. TRPA1 is activated by various potentially harmful electrophilic substances. The chemical warfare agent sulfur mustard (SM) is a highly reactive alkylating agent that binds to numerous biological targets. Although SM is known for almost 200 years, detailed knowledge about the pathophysiology resulting from exposure is lacking. A specific therapy is not available. In this study, we investigated whether the alkylating agent 2-chloroethyl-ethylsulfide (CEES, a model substance for SM-promoted effects) and SM are able to activate TRPA1 channels. CEES induced a marked increase in the intracellular calcium concentration ([Ca(2+)]i) in TRPA1-expressing but not in TRPA1-negative cells. The TRP-channel blocker AP18 diminished the CEES-induced calcium influx. HEK293 cells permanently expressing TRPA1 were more sensitive toward cytotoxic effects of CEES compared with wild-type cells. At low CEES concentrations, CEES-induced cytotoxicity was prevented by AP18. Proof-of-concept experiments using SM resulted in a pronounced increase in [Ca(2+)]i in HEK293-A1-E cells. Human A549 lung epithelial cells, which express TRPA1 endogenously, reacted with a transient calcium influx in response to CEES exposure. The CEES-dependent calcium response was diminished by AP18. In summary, our results demonstrate that alkylating agents are able to activate TRPA1. Inhibition of TRPA1 counteracted cellular toxicity and could thus represent a feasible approach to mitigate SM-induced cell damage.
Full-text · Article · Nov 2014 · Archive für Toxikologie
"The most common late complication of SM inhalation is respiratory tract injury. There are about 100,000 surviving victims who were exposed to chemical warfare agents in Iran, many with permanent pulmonary disabilities such as bronchiolitis obliterans. "
[Show abstract][Hide abstract]ABSTRACT: Statins have anti-inflammatory effects in patients with chronic obstructive pulmonary disease (COPD). This study designed to evaluate the effects of atorvastatin on serum highly sensitive C-reactive protein (hs-CRP) and pulmonary function in sulfur mustard exposed patients with COPD.
Fifty patients with chronic obstructive pulmonary disease due to sulfur mustard and high serum hs-CRP entered in this study. Participants were randomized to receive 40 mg atorvastatin or placebo in a double-blind clinical trial. Forty-five patients completed the study (n = 23 atorvastatin and n = 22 placebo). Pulse oximetry (SpO2), pulmonary function test (PFT), and 6 min walk distance test (6MWD) was measured. COPD assessment test (CAT) and St. George's respiratory questionnaire (SGRQ) were also completed by patients at the beginning of trial and after 9 weeks of prescription of 40 mg/day atorvastatin or placebo. At fourth week, SpO2, PFT, and 6MWD were again measured. After 9 weeks serum hs-CRP was re-measured.
There was no significant difference between atorvastatin and the placebo group in SpO2, FEV1, and 6MWD after fourth week (P = 0.79, P = 0.12, P = 0.12, respectively). The difference between baseline and ninth week was calculated for two groups of trial and control in term of serum hs-CRP, SpO2, FEV1, and 6MWD. Significant improvement was not observed between two groups in above mentioned variables (P = 0.35, P = 0.28, P = 0.94, P = 0.43, respectively). However, the quality of life was improved by administration of atorvastatin using the CAT score (P < 0.001) and SGRQ total score (P = 0.004).
Atorvastatin does not alter serum hs-CRP and lung functions but may improve quality of life in SM-injured patients with COPD.
Full-text · Article · Feb 2014 · Journal of research in medical sciences