The diversity of the effects of sulfur mustard gas inhalation on respiratory system 10 years after a single, heavy exposure: analysis of 197 cases

Standardised mortality ratios in people exposed to sulphur mustard during the Iran-Iraq war: a retrospective study with 39-year follow-up

OBJECTIVES

Sulphur mustard (SM) is a chemical weapon agent that was extensively used by Iraqi troops during the Iran-Iraq war (1980-1988), resulting in exposure among Iranian military personnel and civilians. However, there is limited and conflicting information about the long-term mortality effects of SM exposure. This study aimed to determine the standardised mortality ratios (SMRs) in individuals exposed to SM gas during the Iran-Iraq war.

STUDY DESIGN

This was a retrospective follow-up study.

METHODS

Data were obtained from the Veterans and Martyr Affair Foundation of Iran (VMAF) regarding all confirmed individuals who were exposed to SM during the Iran-Iraq war (1980-1988) up to 30 March 2019. The mortality rate, cumulative mortality and SMR with 95 % confidence intervals (CIs) were calculated to assess mortality in chemical warfare survivors (CWS), and results were compared with the general Iranian population. Overall survival was analysed using the Kaplan-Meier curve, and the log-rank test was employed to compare survival probability across different categories.

RESULTS

Among the 48,067 confirmed CWS, a total of 4358 (9.1 %) individuals had died by the end of the study period (30 March 2019), with a mean age of 55.5 ± 14.4 years at the time of death. Overall, at the 39-year follow-up, the mortality rate due to all causes of death for people who were exposed to SM was lower than the general Iranian population (SMR: 0.70, 95 % CI: 0.68-0.72). However, cause-specific SMR analysis showed that the mortality rate due to liver cancer (SMR: 1.98, 95 % CI: 1.59-2.45), poisonings (SMR: 1.92, 95 % CI: 1.52-2.38), respiratory disorders (SMR: 1.59, 95 % CI: 1.46-1.73) and multiple myeloma (SMR: 1.72, 95 % CI: 1.06-2.62) were approximately twofold higher in CWS than the general population.

CONCLUSIONS

This study provides valuable insights into the mortality effects of SM exposure among the Iranian population affected by the Iran-Iraq war. The results emphasise the importance of continued monitoring and support for individuals exposed to SM, particularly in the context of managing and addressing the heightened risks associated with liver cancer, poisonings, respiratory disorders and multiple myeloma. Further research and interventions may be necessary to mitigate these specific health challenges in the affected population.

Ophthalmic manifestations and management considerations for emerging chemical threats

Chemical agents have been utilized for centuries in warfare and pose a health threat to civilians and military personnel during armed conflict. Despite treaties and regulations against their use, chemical agent exposure remains a threat and measures to understand their effects and countermeasures for systemic and organ-specific health are needed. Many of these agents have ocular complications, both acute and chronic. This mini-review focuses on key chemical agents including vesicants (mustards, lewisite), nerve agents (sarin, VX), knockdown gasses (hydrogen cyanide), and caustics (hydrofluoric acid). Their ophthalmic manifestations and appropriate treatment are emphasized. Acute interventions include removal of the source and meticulous decontamination, as well as normalization of pH to 7.2-7.4 if alteration of the ocular pH is observed. Besides vigorous lavage, acute therapies may include topical corticosteroids and non-steroid anti-inflammatory therapies. Appropriate personal protective equipment (PPE) and strict donning and doffing protocols to avoid healthcare provider exposure are also paramount in the acute setting. For more severe disease, corneal transplantation, amniotic membrane graft, and limbal stem cell transplantation may be needed. Orbital surgery may be required in patients in whom cicatricial changes of the ocular surface have developed, leading to eyelid malposition. Multidisciplinary care teams are often required to handle the full spectrum of findings and consequences associated with emerging chemical threats.

Long-Term Laryngotracheal Complications After Inhalation Injury: A Scoping Review

Long-term laryngotracheal complications (LTLC) after inhalation injury (II) are an under-recognized condition in patients with burns. The purpose of this study was to systematically review all available evidence on LTLC after II and identify gaps in knowledge to guide the direction of future research. A scoping review was performed to synthesize all available evidence on LTLC after II, as guided by the question, "What are the LTLC after II, in patients with or without a history of translaryngeal intubation and/or tracheostomy?". MEDLINE, Web of Science, Ovid Embase, Cochrane Library, and Google Scholar were searched for publications on this topic. Of the 3567 citations screened, a total of 153 full-text articles were assessed for eligibility and 49 were included in the scoping review. The overall level of evidence was low, with case reports constituting 46.7% of all included human studies. The lesions were most frequently in the trachea (36.9%), followed by the glottis (34.7%) and subglottis (19.0%). LTLC occur in 4.8 to 6.5% of patients after II and these complications are under-recognized in burns patients. The risk factors for LTLC include high-grade II, elevated initial inflammatory responses, prolonged translaryngeal intubation, and a history of tracheostomy. The goal of management is to restore airway patency, preserve voice quality, and restore normal diet and swallow function. There is limited high-level evidence on LTLC, particularly with regards to long-term functional morbidity in voice and swallow. Large, prospective studies are required to address this gap in knowledge.

The predictive association between radiological findings and lung cancer development in patients exposed to sulfur mustard gas: 4 decades follow up of 719 victims

BACKGROUND

Respiratory diseases are the leading cause of morbidity and mortality in the survivors exposed to Sulfur Mustard (SM). The late abnormalities can be present as chronic bronchitis, tracheobronchial stenosis, asthma, bronchiectasis, airway narrowing, lung fibrosis, and lung cancers. This study aims to investigate the association between radiological findings and lung cancer development in patients exposed to sulfur mustard gas.

METHODS

We entered 719 victims exposed to SM during the Iran-Iraq war into our follow-up study in a consensus manner. They were periodically followed with Chest HRCT scans from 2001 to an interval of 2014-2019. The mean year interval between exposure and the last follow-up was 38 years. For confirming the lung cancer in those with evidence of malignancy in their imaging, fine needle aspiration/biopsy and/or surgical intervention were done.

RESULTS

Among 719 patients, 57% were free from any pathologic findings in their HRCT scan. Among the subjects who had the abnormal radiologic findings, Air Trapping (AT), Lung Fibrosis (LF), Bronchiectasis (B), and the evidence of lung cancer were found in 265 (36.9%), 207 (28.8%), 151 (21.0%), and 42 (5.8%), respectively. Adenocarcinoma (38.1%) was the most common type of cancer. The right lung was involved more than the left one regarding LF, B, and cancer (p value < 0.05). Considering the laterality, a significant correlation was found between the side of LF and B and the tumor side. Furthermore, it was shown that the lung lobes with LF were statistically correlated to tumor-involved lobes. The relative risk of AT and B existence for tumor development was 11.73 [4.87-28.26] and 10.14 [5.12-20.090], respectively. The most predictive finding was LF which caused the risk of developing tumor 17.75 [7.35-42.86] times higher in the patient with this pathology. By each increment of the number of LF and B, the risk of developing tumors increased by 51% and 76%, respectively.

CONCLUSION

In survivors exposed to Sulfur Mustard, those with bronchiectasis and lung fibrosis have a significantly higher risk of developing lung cancers, so a close follow-up of these victims is recommended. Trial registration This study was confirmed by the institutional review board and ethics committee at Shiraz University of Medical Sciences (SUMS) with the ethical code IR.SUMS.MED.REC.1399.637.

Possible Treatment Approaches of Sulfur Mustard-Induced Lung Disorders, Experimental and Clinical Evidence, an Updated Review

Sulfur mustard (SM) is one of the major potent chemical warfare that caused the death of victims in World War I and the Iraq-Iran conflict (1980-1988). The respiratory system is the main target of SM exposure and there are no definitive therapeutic modalities for SM-induced lung injury. The effects of the new pharmaceutical drugs on lung injury induced by SM exposure were summarized in this review. Literature review on PubMed, ScienceDirect, and Google Scholar databases was performed to find papers that reported new treatment approach on SM-exposure-induced injury in the respiratory system until October 2019. The search was restricted to sulfur mustard AND induced injury (in vitro studies, animal experiments, and clinical trials) AND respiratory system OR lung, AND treatment in all fields. Two hundred and eighty-three relevant articles were identified that 97 retrieved articles were eligible and were included in the review. Some new pharmaceutical drugs have shown therapeutic potential in controlling various characteristics of lung injury due to SM exposure. Recent studies showed therapeutic effects of mucolytic drugs, non-steroidal drugs, and antibiotics on reducing lung inflammation, oxidative stress responses, and modulating of the immune system as well as improving of respiratory symptoms and pulmonary function tests. Studies on the therapeutic effects of new agents with amelioration or treatment of SM-induced lung injury were reviewed and discussed.

Advice on assistance and protection provided by the Scientific Advisory Board of the Organisation for the Prohibition of Chemical Weapons: Part 3. On medical care and treatment of injuries from sulfur mustard

Blister agents damage the skin, eyes, mucous membranes and subcutaneous tissues. Other toxic effects may occur after absorption. The response of the Scientific Advisory Board (SAB) of the Organisation for the Prohibition of Chemical Weapons (OPCW) to a request from the OPCW Director-General in 2013 on the status of medical countermeasures and treatments to blister agents is updated through the incorporation of the latest information. The physical and toxicological properties of sulfur mustard and clinical effects and treatments are summarised. The information should assist medics and emergency responders who may be unfamiliar with the toxidrome of sulfur mustard and its treatment.

Possible treatment with medicinal herbs and their ingredients of lung disorders induced by sulfur mustard exposures: a review

Chemical warfare (CW) agents are toxic synthetic chemicals that affect human's health, and sulfur mustard (SM) is a well-known chemical weapon that caused deaths of victims. The lung is the main target of SM exposure, and there are no definitive therapeutic modalities for lung injury induced by this agent. The possible therapeutic effects of medicinal plants and their active ingredients on lung injury induced by SM were reviewed in this article until the end of June 2021. Medicinal plants including Crocus sativus, Curcuma longa, Thymus vulgaris, Nigella sativa, and Zataria multiflora and also natural compounds showed therapeutic potential in improving of various features of lung injury induced by SM and other related chemical agents. Several studies showed therapeutic effects of some medicinal plants and natural products on lung inflammation, oxidative stress, and immune responses in experimental studies in SM-induced lung injury. In addition, clinical studies also showed the effect of medicinal plants and natural compounds on respiratory symptoms, pulmonary function tests (PFTs), and inflammatory markers. The therapeutic effects of medicinal plants and natural products on lung disorder induced by SM and related chemical agents were shown through amelioration of various features of lung injury.

Exposure to sulfur mustard increases the risk for mortality in patients with COVID-19 infection: A cohort study

Objective

This study aims to assess the prognosis of inpatients with COVID-19 infection who have a history of sulfur mustard exposure.

Methods

We started a cohort study in October 2020 and ended in May 2021 on inpatients with COVID-19 infection who had been admitted to university healthcare centers. The analytic sample included 960 inpatients having COVID-19 infection (192 with; and 768 without sulfur mustard exposure). The exposed patients were male war veterans, and the unexposed patients were male individually age-matched people. All patients had a positive RT-PCR test and a positive chest CT for COVID-19. The outcome was death within 28 days of admission, and the predictors were clinical features recorded at patients' bedsides.

Results

There was a significantly higher prevalence for asthma (p = 0.026) and pulmonary disease other than asthma (p < 0.001) in patients with the exposure. Sulfur mustard exposure was associated with increased risk for mortality of COVID-19 [hazard ratio (95% CI) = 1.92 (1.14,3.24), p = 0.013]. Early intubation signified a poor prognosis [hazard = 7.34 (4.65,11.58), p < 0.001]. However, individuals with higher PaO2 [hazard = 0.97 (0.95,0.98), p < 0.001], or people undergoing O2 therapy early upon admission [hazard = 0.58 (0.38,0.89), p = 0.011] showed lower risks for mortality. Individuals with asthma were at higher risk for mortality [hazard = 3.76 (1.69,8.36), p = 0.001].

Conclusion

Individuals with COVID-19 infection and sulfur mustard exposure should be considered high-risk patients and that, healthcare settings should be ready to provide critical care for them, including O₂ therapy. They are more likely to have asthma or other pulmonary diseases.

Inhalational Constrictive Bronchiolitis: The Evolution of our Understanding of this Disease

The case definition of inhalational constrictive bronchiolitis (CB) has changed over the generations. We identify changes in the description of this illness over time associated with different exposures and present the natural history of CB in a case attributed to military burn pit exposure. The initial descriptions of this disease began with nitric acid spills and silage exposures. In these events, there was an acute exposure, typically a short-term resolution of the adverse respiratory events, and then a progression, leading to disability or a respiratory death. The life-saving role of corticosteroid therapy in this situation was recognized. War gas exposures of World War I and then Saddam Hussein's use of sulfur mustard gas in the Iran-Iraq War followed. More recently the findings associated with diacetyl exposure in commercial popcorn workers remained consistent with previously described presentations, but then the clinical presentation in troops returning from deployment to Southwest Asia was very different, yet with the same histologic findings. We recognize unreconciled disparities in the clinical, physiologic, and imaging presentation in those with inhalational bronchiolitis and acknowledge this as perhaps one of the difficult diagnoses in respiratory medicine.

A novel sulfur mustard (HD) vapor inhalation exposure model of pulmonary toxicity for the efficacy evaluation of candidate medical countermeasures

OBJECTIVE

To develop a novel inhalation exposure system capable of delivering a controlled inhaled HD dose through an endotracheal tube to anesthetized rats to investigate the lung pathophysiology and evaluate potential medical countermeasures.

MATERIALS AND METHODS

Target HD vapor exposures were generated by a temperature-controlled vapor generator, while concentration was monitored near real-time by gas chromatography. Animal breathing parameters were monitored real-time by in-line EMKA/SciReq pulmonary analysis system. Individual exposures were halted when the target inhaled doses were achieved. Animals were observed daily for clinical observations and lethality with scheduled termination at 28 days post-exposure. Upon scheduled or unscheduled death, animals underwent a gross necropsy and lung and trachea were collected for histopathology.

RESULTS

Controlled HD concentrations ranged from 60 to 320 mg/m³. Delivered inhaled doses range from 0.3 to 3.20 mg/kg with administered doses within 3% of the target. The 28-day inhaled LD₅₀ is 0.80 mg/kg (95% CI = 0.42-1.18 mg/kg). Post exposure respiratory abnormalities were observed across all dose levels though the higher dose levels had earlier onset and higher frequency of occurrence. Histopathologic alterations were not qualitatively altered in accordance with dose but instead showed a relationship to an animals' time of death, with early deaths demonstrating acute damage and later deaths displaying signs of repair.

DISCUSSION/CONCLUSION

This novel exposure system administers targeted HD inhaled doses to generate a small animal model that can be used to evaluate physiological toxicities of inhaled HD on the lungs and for evaluation of potential medical countermeasure treatments.

The effect of atorvastatin on inflammatory markers in sulfur mustard gas induced bronchitis: a randomized double-blinded, placebo-control clinical trial

Background

This study was performed to evaluate the anti-inflammatory effect of atorvastatin in patients with chronic bronchitis, exposed to sulfur mustard gas.

Methods

In this randomized double-blinded clinical trial we recruited patients with chronic bronchitis after exposure to sulfur mustard gas. Ninety men 45–75 years old diagnosed with chronic bronchitis after exposure to mustard gas during the Iran-Iraq war, were randomly assigned to receive either atorvastatin (40 mg) or placebo once a day for 3 months. The interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), procalcitonin, highly sensitive CRP and COPD assessment test (CAT) score was compared at baseline and after 12 weeks.

Results

After consuming atorvastatin for 12 weeks, IL-6 level (mean difference [95%CI]; 0.2 [− 0.05, 0.5]), TNF-α (mean difference [95%CI]; − 0.07 [− 0.2, 0.07]), high sensitive CRP (mean difference [95%CI] − 0.1 [− 1.2, 0.9]), and procalcitonin (mean difference [95%CI]; 0.003 [− 0.02, 0.03]) did not change significantly. However, in the placebo group, only IL-6 (mean difference [95%CI]; 0.6 [0.2, 1.05]) decreased significantly after 12 weeks, but levels of high sensitive CRP (mean difference [95%CI]; − 0.3 [− 1.4, 0.8]) TNF-α (mean difference [95%CI]; − 0.2 [− 0.34, − 0.06]) and procalcitonin (mean difference [95%CI]; 0.02 [− 0.001, 0.04]) did not change significantly. After 12 weeks, the mean differences in TNF- α, IL-6 level, high sensitive CRP, procalcitonin, and CAT score did not significantly differ between the two groups.

Conclusions

The administration of 40 mg atorvastatin for 3 months did not significantly change the inflammatory markers or the quality of life of patients exposed to mustard gas with chronic bronchitis.

Trial registration: IRCT, IRCT138904144312N1. Registered 16 August 2014, https://en.irct.ir/trial/4577.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01481-y.

Deciphering the role of microRNAs in mustard gas-induced toxicity

Mustard gas (sulfur mustard, SM), a highly vesicating chemical warfare agent, was first deployed in warfare in 1917 and recently during the Iraq-Iran war (1980s) and Syrian conflicts (2000s); however, the threat of exposure from stockpiles and old artillery shells still looms large. Whereas research has been long ongoing on SM-induced toxicity, delineating the precise molecular pathways is still an ongoing area of investigation; thus, it is important to attempt novel approaches to decipher these mechanisms and develop a detailed network of pathways associated with SM-induced toxicity. One such avenue is exploring the role of microRNAs (miRNAs) in SM-induced toxicity. Recent research on the regulatory role of miRNAs provides important results to fill in the gaps in SM toxicity-associated mechanisms. In addition, differentially expressed miRNAs can also be used as diagnostic markers to determine the extent of toxicity in exposed individuals. Thus, in our review, we have summarized the studies conducted so far in cellular and animal models, including human subjects, on the expression profiles and roles of miRNAs in SM- and/or SM analog-induced toxicity. Further detailed research in this area will guide us in devising preventive strategies, diagnostic tools, and therapeutic interventions against SM-induced toxicity.

Long-term Health Outcomes Among Survivors Exposed to Sulfur Mustard in Iran

IMPORTANCE

The prevalence and severity of long-term health complications after exposure to sulfur mustard are unknown.

OBJECTIVE

To investigate the long-term health outcomes among survivors exposed to sulfur mustard during the Iran-Iraq War.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective cohort study, late-onset health complications of 64 190 Iranian survivors exposed to sulfur mustard during the Iran-Iraq War from 1980 to 1988 were investigated using descriptive statistics. Data involving affected organs and symptom severity were extracted from the Veterans and Martyr Affair Foundation (VMAF) database from 1980 to 2019. Assessments were conducted across 3 groups depending on whether survivors were (1) evacuated and admitted (EA) to a hospital; (2) not evacuated or admitted (NEA) to a hospital; or (3) evacuation or admission status was not documented.

EXPOSURES

Analysis of chronic symptom severity following exposure to sulfur mustard.

MAIN OUTCOMES AND MEASURES

Mild, moderate, or severe rankings of symptoms in lungs, eyes, and skin of survivors exposed to sulfur mustard using data from the VMAF database.

RESULTS

Of 64 190 chemical survivors registered in the VMAF database, 60 861 met the inclusion criteria. Of the included survivors, 98.0% were male, and the mean (SD) age was 23.5 (7.7) years. Most survivors (53 675 [88.2%]) had no symptoms or mild lesions, and 7186 survivors (11.8%) had moderate or severe complications. Moderate to severe lung (6540 [10.7%]), eye (335 [0.6%]), or skin (725 [1.2%]) injuries were documented in the exposed population. The proportion of moderate plus severe late complications in eyes was 3 times as high in male survivors compared with female survivors (0.6% [95% CI, 0.53%-0.65%] vs 0.2% [95% CI, 0.09%-0.73%]; P < .001), whereas dermal complications were significantly more common in female survivors (3.9% [95% CI, 2.92%-5.11%] vs 1.14% [95% CI, 1.06%-1.23%]; P < .001). Mild lung lesions were more prevalent in the NEA group than in the EA group (73.9% [95% CI, 73.4%-74.4%] vs 11.0% [95% CI, 10.6%-11.3%]; P < .001). In the NEA group, 83.2% (n = 23 866) developed lung injuries that were mostly mild or moderate, whereas 77% (n = 24 766) of the EA group did not develop lung injuries (P < .001).

CONCLUSIONS AND RELEVANCE

The present study found sex differences in the frequencies of eye and skin complications following sulfur mustard exposure, and lung complications were more prevalent years after sulfur mustard exposure than soon after exposure. Mild lung lesions were observed more frequently among sulfur mustard-exposed survivors who had not been evacuated or hospitalized than among those who had been evacuated or hospitalized. These differences may be due to physiological response or dose of exposure. Close monitoring over an extended period may be required for detection of late pulmonary complications in individuals exposed to sulfur mustard.

Are Iranian Sulfur Mustard Gas-Exposed Survivors More Vulnerable to SARS-CoV-2? Some Similarity in Their Pathogenesis

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that emerged as a health problem worldwide. It seems that COVID-19 is more lethal for Iranian veterans with a history of exposure to mustard gas. There are some similarities in the pathogenesis of SARS-CoV-2 and mustard gas in immune system disruption and pulmonary infection. SARS-CoV-2 and mustard gas inducing oxidative stress, immune system dysregulation, cytokine storm, and overexpression of angiotensin-converting enzyme II (ACE2) receptor in lungs that act as functional entry receptors for SARS-CoV-2. Moreover, Iranian survivors of mustard gas exposure are more susceptible and vulnerable to COVID-19. It is suggested that the principles of COVID-19 infection prevention and control be adhered to more stringently in Iranian survivors of mustard gas exposure than others who have not been exposed to mustard gas. Therefore, in this review, we discuss the different pathologic aspects of lung injury caused by mustard gas and also the relationship between this damage and the increased susceptibility of Iranian mustard gas exposed survivors to COVID-19.

Progressive Lung Injury, Inflammation, and Fibrosis in Rats Following Inhalation of Sulfur Mustard

Sulfur mustard (SM) inhalation causes debilitating pulmonary injury in humans which progresses to fibrosis. Herein, we developed a rat model of SM toxicity which parallels pathological changes in the respiratory tract observed in humans. SM vapor inhalation caused dose (0.2-0.6 mg/kg)-related damage to the respiratory tract within 3 days of exposure. At 0.4-0.6 mg/kg, ulceration of the proximal bronchioles, edema and inflammation were observed, along with a proteinaceous exudate containing inflammatory cells in alveolar regions. Time course studies revealed that the pathologic response was biphasic. Thus, changes observed at 3 days post-SM were reduced at 7-16 days; this was followed by more robust aberrations at 28 days, including epithelial necrosis and hyperplasia in the distal bronchioles, thickened alveolar walls, enlarged vacuolated macrophages, and interstitial fibrosis. Histopathologic changes were correlated with biphasic increases in bronchoalveolar lavage (BAL) cell and protein content and proliferating cell nuclear antigen expression. Proinflammatory proteins receptor for advanced glycation end product (RAGE), high-mobility group box protein (HMGB)-1, and matrix metalloproteinase (MMP)-9 also increased in a biphasic manner following SM inhalation, along with surfactant protein-D (SP-D). Tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS), inflammatory proteins implicated in mustard lung toxicity, and the proinflammatory/profibrotic protein, galectin (Gal)-3, were upregulated in alveolar macrophages and in bronchiolar regions at 3 and 28 days post-SM. Inflammatory changes in the lung were associated with oxidative stress, as reflected by increased expression of heme oxygenase (HO)-1. These data demonstrate a similar pathologic response to inhaled SM in rats and humans suggesting that this rodent model can be used for mechanistic studies and for the identification of efficacious therapeutics for mitigating toxicity.

A review of Sulfur Mustard-induced pulmonary immunopathology: An Alveolar Macrophage Approach

Despite many studies investigating the mechanism of Sulfur Mustard (SM) induced lung injury, the underlying mechanism is still unclear. Inflammatory and subsequent fibroproliferative stages of SM-toxicity are based upon several highly-related series of events controlled by the immune system. The inhalation of SM gas variably affects different cell populations within the lungs. Various studies have shown the critical role of macrophages in triggering a pulmonary inflammatory response as well as its maintenance, resolution, and repair. Importantly, macrophages can serve as either pro-inflammatory or anti-inflammatory populations depending on the present conditions at any pathological stage. Different characteristics of macrophages, including their differentiation, phenotypic, and functional properties, as well as interactions with other cell populations determine the outcomes of lung diseases and the extent of long- or short-term pulmonary damage induced by SM. In this paper, we summarize the current state of knowledge regarding the role of alveolar macrophages and their mediators in the pathogenesis of SM in pulmonary injury. Investigating the specific cells and mechanisms involved in SM-lung injury may be useful in finding new target opportunities for treatment of this injury.

Late Cardiac Complications of Sulfur Mustard Poisoning in 38 Iranian Veterans

It was aimed to investigate possible late cardiac effects of Sulfur mustard (SM) exposure in Iranian veterans. Thirty-eight veterans with late complications of SM exposure were investigated. Clinical history, physical examinations, 12 leads electrocardiography and transthoracic echocardiography were performed. Computed tomography coronary angiography (CTCA) was performed as clinically indicated for angiographic assessment and patients were stratified according to the CTCA findings. Incomplete right bundle branch block and right axis deviation were detected in 3 (7.9%) and 4 (10.5%) cases, respectively. Mean value of left ventricular ejection fraction was 55.7 ± 2.9%. Different degrees of right ventricular dilation was observed in seven (18.4%) patients. All the patients showed mild to moderate degrees of tricuspid regurgitation. Increased pulmonary artery pressure (PAP) was detected in 16 (42.1%) patients. Out of 18 patients who underwent CTCA, non-obstructive and obstructive coronary artery disease (CAD) were observed in three (16.66%) and eight (44.44%) patients, respectively. CAD was stratified to single vessel (5.5%), two vessels (27.8%) and three vessels disease (11.1%). Mean coronary artery calcium score was 50.91 ± 115.58. SM has cardiovascular toxicity, as a delayed complication of this chemical warfare poisoning.

Effect of Zataria multiflora on serum cytokine levels and pulmonary function tests in sulfur mustard-induced lung disorders: A randomized double-blind clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Zataria multiflora (Z. multiflora) belongs to the Lamiaceae family and has several traditional uses owing to its antiseptic, aesthetic, antispasmodic, analgesic, and antidiarrheal properties.

AIM OF THE STUDY

We aimed to investigate the effect of Z. multiflora on serum cytokine levels and pulmonary function tests (PFT) in patients exposed to sulfur mustard (SM) for a long term (27-30 years).

MATERIALS AND METHODS

Thirty-five patients were randomly assigned to the placebo group (P) and two experimental groups treated with Z. multiflora extracts, i.e., 5 and 10 mg/kg/day (Z5 and Z10). Serum levels of cytokines including IL (2, 4, 6, 8, and 10) and IFN-γ as well as PFT indices such as maximum mid-expiratory flow (MMEF) and maximum expiratory flow at 25, 50, and 75% of vital capacity (VC) (MEF25, 50, and 75) were assessed at the beginning (phase 0) and at the end of 4 and 8 weeks (phases I and II, respectively) after starting the treatment.

RESULTS

Serum levels of IL-2, IL-6, and IL-8 were significantly decreased, while serum levels of IL-10 and IFN-γ were significantly increased in the Z5 and Z10 treatment groups in phases I and II as compared to those in phase 0 (p < 0.05 to p < 0.001). MMEF and MEF25, 50, and 75 values were significantly increased in the Z5 group in phase II and in the Z10 group in phases I and II compared to those in phase 0 (p < 0.05 to p < 0.001). The percent change in serum cytokine levels and the change in MEF25, 50, and 75 during the two-month treatment period were significantly higher in the treatment groups than in the placebo group.

CONCLUSIONS

Two months of treatment with Z. multiflora reduced inflammation, while it enhanced anti-inflammatory cytokines and improved PFT indices in SM-exposed patients.

Long-term Respiratory Effects of Mustard Vesicants

Sulfur mustard and related vesicants are cytotoxic alkylating agents that cause severe damage to the respiratory tract. Injury is progressive leading, over time, to asthma, bronchitis, bronchiectasis, airway stenosis, and pulmonary fibrosis. As there are no specific therapeutics available for victims of mustard gas poisoning, current clinical treatments mostly provide only symptomatic relief. In this article, the long-term effects of mustards on the respiratory tract are described in humans and experimental animal models in an effort to define cellular and molecular mechanisms contributing to lung injury and disease pathogenesis. A better understanding of mechanisms underlying pulmonary toxicity induced by mustards may help in identifying potential targets for the development of effective clinical therapeutics aimed at mitigating their adverse effects.

Bronchiolitis Obliterans and Pulmonary Fibrosis after Sulfur Mustard Inhalation in Rats

Inhalation of powerful chemical agents, such as sulfur mustard (SM), can have debilitating pulmonary consequences, such as bronchiolitis obliterans (BO) and parenchymal fibrosis (PF). The underlying pathogenesis of disorders after SM inhalation is not clearly understood, resulting in a paucity of effective therapies. In this study, we evaluated the role of profibrotic pathways involving transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF) in the development of BO and PF after SM inhalation injury using a rat model. Adult Sprague-Dawley rats were intubated and exposed to SM (1.0 mg/kg), then monitored daily for respiratory distress, oxygen saturation changes, and weight loss. Rats were killed at 7, 14, 21, or 28 days, and markers of injury were determined by histopathology; pulmonary function testing; and assessment of TGF-β, PDGF, and PAI-1 concentrations. Respiratory distress developed over time after SM inhalation, with progressive hypoxemia, respiratory distress, and weight loss. Histopathology confirmed the presence of both BO and PF, and both gradually worsened with time. Pulmonary function testing demonstrated a time-dependent increase in lung resistance, as well as a decrease in lung compliance. Concentrations of TGF-β, PDGF, and PAI-1 were elevated at 28 days in lung, BAL fluid, and/or plasma. Time-dependent development of BO and PF occurs in lungs of rats exposed to SM inhalation, and the elevated concentrations of TGF-β, PDGF, and PAI-1 suggest involvement of these profibrotic pathways in the aberrant remodeling after injury.

The study of genes and signal transduction pathways involved in mustard lung injury: A gene therapy approach

Sulfur mustard (SM) is a destructive and harmful chemical agent for the eyes, skin and lungs that causes short-term and long-term lesions and was widely used in Iraq war against Iran (1980-1988). SM causes DNA damages, oxidative stress, and Inflammation. Considering the similarities between SM and COPD (Chronic Obstructive Pulmonary Disease) pathogens and limited available treatments, a novel therapeutic approach is not developed. Gene therapy is a novel therapeutic approach that uses genetic engineering science in treatment of most diseases including chronic obstructive pulmonary disease. In this review, attempts to presenting a comprehensive study of mustard lung and introducing the genes therapy involved in chronic obstructive pulmonary disease and emphasizing the pathways and genes involved in the pathology and pathogenesis of sulfur Mustard. It seems that, given the high potential of gene therapy and the fact that this experimental technique is a candidate for the treatment of pulmonary diseases, further study of genes, vectors and gene transfer systems can draw a very positive perspective of gene therapy in near future.

Chemical Agents in Disaster: Care and Management in the Intensive Care Unit

Chemical agents of warfare are divided into lung agents, blood agents, vesicants, and nerve agents. Intensivists must familiarize themselves with the clinical presentation and management principles in the event of a chemical attack. Key principles in management include aggressive supportive care and early administration of specific antidotes, if available. Management includes proper personal protection for critical care providers. Patients may make complete recovery with aggressive supportive care, even if they appear to have a poor prognosis. Hospitals must have an emergency response disaster plan in place to deal with all potential causes of disasters, including illnesses resulting from chemical agents.

An inhalational swine model for the characterization of physiological effects and toxicological profile associated with cyanide poisoning

Cyanides are highly toxic compounds that have been used as weapons of terrorism throughout history. Cyanide (CN) is acutely toxic by all routes of administration; however, inhalation is the main exposure route. To adequately test effective countermeasures against inhalational CN threats, robust and well-characterized animal models are needed. This paper describes the initial development of a hydrogen cyanide (HCN) exposure swine model for documenting the physiological effects and toxicological profile during and after HCN inhalation exposure. Animals were implanted with telemetry transmitters for heart rate (HR), blood pressure, and electrocardiogram monitoring, and vascular access ports for serial blood collections. Nine female swine were exposed to HCN concentrations of 500 ± 6 ppm while breathing parameters were monitored real-time. Inhaled HCN doses ranged from 2.02 to 2.83 mg/kg. Clinical signs included vocalization, agitation, salivation, respiratory distress and apnea. After HCN exposure initiation, systemic arterial pressure fell dramatically with a concomitant increase in HR. Blood samples were collected to determine CN blood levels using LC-MS/MS and blood gas analysis. In summary, the developed HCN inhalation swine model permitted documentation of the physiological effects associated with CN poisoning. This model could be used to evaluate potential CN medical countermeasures in the event of a public health emergency stemming from inhalational CN threats.

Pulmonary rehabilitation in patients with mustard gas lung disease: a study protocol for a randomized controlled trial

Background

More than 60,000 people have health problems due to chemical weapons exposure during the Iran–Iraq war. Respiratory consequences of mustard gas exposure are common and disabling; medical interventions have limited effect. Patients complain of cough, sputum, breathlessness and exercise limitation. We hypothesized that patients with this condition would benefit from pulmonary rehabilitation.

Methods

We outline the protocol for an assessor-blind, two-armed, parallel-design randomized controlled clinical trial (IRCT2016051127848N1). Sixty patients with respiratory disease due to documented sulfur mustard gas exposure will be randomized to either take part in a 6-week pulmonary rehabilitation programme or receive usual care. Inclusion criteria include forced expiratory volume in 1 second < 80% predicted and Medical Research Council dyspnoea score ≥ 3. The primary endpoint will be the change in cycle endurance time at 70% baseline exercise capacity at 6 weeks. Lung function, physical activity, the strength and endurance of the quadriceps muscle, and quality of life will also be compared. Outcomes will be assessed at 6 weeks and 12 months. Health care utilization will also be assessed.

Discussion

If the study confirms that rehabilitation is effective for patients with mustard gas lung disease this should prompt provision of the intervention to this patient group.

Trial registration

Iranian Registry of Clinical Trials, IRCT2016051127848N1. Registered on 24 May 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3180-3) contains supplementary material, which is available to authorized users.

The Role of Magnetic Resonance Spectroscopy in Evaluating the Rate of Brain Metabolic Variations in Chemical Veterans with Respiratory Problem In Comparison To Control Group

BACKGROUND

During the eight years of the imposed war, Iraq used various chemical agents such as sulfur mustard and nerve agents (mainly tabun and sometimes soman) on Iran's soldiers. Using information obtained from specialist sequences and analysing information obtained from magnetic resonance imaging (MRI) in a susceptibility weighted imaging (SWI) sequence and magnetic resonance spectroscopy (MRS) provides valuable information on continuation of treatment and identifying functional disorders.

AIM

The objective of this research was to evaluate the rate of metabolic variations in chemically injured veterans based on chemical neuromarkers using the chemical sequence MRS, which would help patients and physicians in terms of time, economics, and selection of appropriate therapeutic methods, so if the can physician can get complete information about the metabolic properties of the brain through paraclinical (especially MRI) tools before treatment, he might change his treatment program to reduce the complications caused by it.

METHODOLOGY

In this research, 40 chemically injured veterans with brain dysfunction admitted to the screening centre for MRI with specialized MRS sequence participated. Accordingly, we examined the rate of brain metabolic variations about the level of neuromarkers and evaluated the relationship between the level of neuromarkers and brain damages.

RESULTS

The results of this research revealed that while the demographic characteristics such as age of the two groups of chemically injured veterans and control was similar, only the median of the NAA/Cr (N-acetylaspartate to creatine ratio) ratio in PONS of chemically injured patients was significantly lower than that of the control group, and this ratio was similar in other parts of the brain in two groups. The results also showed that the ratio of NAA to total choline and Cr was similar in all parts of the brain in two groups.

CONCLUSION

Based on the research results, using the MR (Magnetic Resonance) spectroscopy device and determination of the value and ratio of markers such as creatinine and N-acetylaspartate and choline, the brain injuries of chemically injured veterans can be examined. By conducting further studies and larger sample size, the brain damages in veterans can be diagnosed early, which would be a great contribution in their treatment.

Carvacrol ameliorates haematological parameters, oxidant/antioxidant biomarkers and pulmonary function tests in patients with sulphur mustard-induced lung disorders: A randomized double-blind clinical trial

WHAT IS KNOWN AND OBJECTIVE

In this study, the effect of carvacrol (CAR) on pulmonary function tests (PFT), haematological indices and oxidant/antioxidant biomarkers in patients with sulphur mustard (SM)-induced lung disorders was examined.

METHODS

Twenty patients exposed to SM 27-30 years ago were divided into two groups and treated with either placebo (P) or CAR (1.2 mg/kg per day) (n = 10 for each group). Forced vital capacity (FVC), peak expiratory flow (PEF), total and different white blood cell (WBC), haematological parameters and oxidant/antioxidant biomarkers were measured at the baseline (step 0), one and two months (steps I and II, respectively) after starting the treatment.

RESULTS AND DISCUSSION

PEF was significantly increased in the CAR-treated group in step II compared to step 0 (P < .01). Total WBC (P < .01) and neutrophil (P < .05) count in the CAR-treated group were significantly decreased in the group in steps I and II (P < .01 for both cases) compared to step 0. The levels of thiol, superoxide dismutase and catalase in the CAR-treated group were significantly increased (P < .05 to P < .001) in steps I and II, but malondialdehyde significantly decreased in step II compared to step 0 (P < .01). The percentage of total and differential WBC, oxidant/antioxidant biomarkers, FVC and PEF values following a two-month treatment period were significantly improved in the CAR-treated group compared to the placebo group (P < .05 to P < .001).

WHAT IS NEW AND CONCLUSION

Two-month treatment with CAR reduced inflammatory cells and oxidant biomarkers, whereas increased antioxidant biomarkers and improved PFT tests in SM-exposed patients.

The effect of Zataria multiflora on pulmonary function tests, hematological and oxidant/antioxidant parameters in sulfur mustard exposed veterans, a randomized doubled-blind clinical trial

BACKGROUND

Sulfur mustard is an alkylating agent which cause to short and long term incapacitations on various organs including lung. There is no definite treatment for lung disorders induced by SM exposure. In the present study, the preventive effect of Zataria multiflora (Z. multiflora) on hematological parameters, oxidant/antioxidant markers and pulmonary function tests (PFT) in veterans, 27-30 years after exposed to SM were studied.

MATERIALS AND METHODS

Forty seven veterans allocated to three groups included: placebo group (P) and two groups treated with 5 and 10 mg/kg/day of Z. multiflora (Zat 5 and Zat 10). Drugs were prescribed in a double-blind manner for two months. Total and different WBC, hematological indices, oxidant/antioxidant markers and PFT values included; force vital capacity (FVC) and peak expiratory flow (PEF) were assessed at the beginning (step 0), one and two month (step I and II, respectively) after starting treatment.

RESULTS

Total and different white blood cell in Zat 5 and 10 mg/kg treated groups in Step I and II were significantly decreased compared to Step 0 (p < 0.05 to p < 0.001). The levels of thiol, superoxide dismutase (SOD) and catalase (CAT) in Zat 5 and 10 mg/kg treated groups in step I and II were significantly increased (p < 0.05 to p < 0.001) but the level of malondialdehyde (MDA) significantly decreased in two treatment groups compared to Step 0 (p < 0.05 and p < 0.001 respectively). FVC and PEF values were significant increase in Zat 5 and 10 mg/kg treated groups in step I and II compared to step 0 (p < 0.05 to p < 0.001). Furthermore, FVC and PEF values in Zat 5 mg/kg were also increased in step II compared to step I (p < 0.01 for both). The percentage improvement of total and differential WBC, oxidant/antioxidant markers, FVC and PEF values during two moth treatment period significantly improved in the treated groups compared to the placebo group.

CONCLUSION

Z. multiflora reduces inflammatory cells and oxidant biomarkers, while increase antioxidant biomarkers and improved PFT tests in SM exposed patients in a two moth treatment period.

Whole body exposure of rats to sulfur mustard vapor

Sulfur mustard (SM) is an incapacitating chemical warfare agent used in numerous conflicts around the world and it is still a major threat for both, army troops and civilians. To evaluate its multiple targets effects in experimental setup, a model of whole body exposure (WBE) to SM vapor was established in rats and its simultaneous effects on lungs and eyes as well as on general wellbeing were examined. Rats were exposed to SM vapor. Evaluation (up to 10 weeks post-exposure) included body weight, general observation, blood counts and histological analysis. Results showed that following a latency-period of several hours, rats typical symptoms developed over a period of more than one week. The initial symptoms, characterized by swollen and erythematic nose, deteriorated into extensive rhinorrhea, eye closure, excessive lacrimation as well as rhonchi, wheezing and breathing difficulties. Alopecia and behavioral abnormality were also recorded. A weight loss of up to 40% was measured within one week with spontaneous recovery to baseline level within three weeks after exposure. Blood counts revealed leukopenia during the first three days post-exposure. Histological evaluation revealed a long lasting damage to the trachea, lungs and eyes. Thus, WBE to SM, was found to closely mimic the deleterious effects of SM on the sensitive tissues previously described in human victims during WWI and the Iran-Iraq war. The use of this animal model will enable comprehensive characterization of changes in biological processes that may lead to the development of therapeutic measures to ameliorate SM induced multi-system injuries.

Long-term health effects of chemical warfare agents on children following a single heavy exposure

In the 1980s, villages in the Kurdistan region of Iraq were exposed to chemical weapons (CWs), which killed and injured thousands of civilians. There has been no clinical assessment of the long-term effects of CWs exposure on those injured. We report the first such evaluation of CW effects on long-term health of children. Patients from the CW-exposed areas were interviewed to assess previous and current clinical history and underwent clinical examination. The status of organs known to be targets of CWs, including skin, eyes, respiratory and neuromuscular systems, was assessed. Children of similar age and social background, but with no history of CW exposure, were selected as a control population. Results showed that 70% of children in the CWs group had chronic health problems in contrast to 3.3% in the unexposed group ( p < 0.0001). Fifty-five per cent of the CW-exposed group had long-term visual impairment but none in the unexposed population. Thirty-six per cent of the CW-exposed group had chronic dermatological conditions compared with 0.8% of the unexposed group ( p < 0.0001), 31% of the CWs group had neurological sequelae compared with 0.4% of the unexposed group ( p < 0.0001) and 51% of the CWs group had long-term respiratory problems compared with 1.5% of the unexposed group ( p < 0.0001). Respiratory complaints including asthma, chronic bronchitis and bronchiectasis were particularly common. Our study suggests that CWs used were probably a combination of sulphur mustard and organophosphate nerve agents. Results also indicate that the prevalence of acute and chronic health problems following exposure to CW agents appear to be higher in children compared with reported data in adults.

Th17/Treg immunoregulation and implications in treatment of sulfur mustard gas-induced lung diseases

INTRODUCTION

Sulfur mustard (SM) is an extremely toxic gas used in chemical warfare to cause massive lung injury and death. Victims exposed to SM gas acutely present with inhalational lung injury, but among those who survive, some develop obstructive airway diseases referred to as SM-lung syndrome. Pathophysiologically, SM-lung shares many characteristics with smoking-induced chronic obstructive pulmonary disease (COPD), including airway remodeling, goblet cell metaplasia, and obstructive ventilation defect. Some of the hallmarks of COPD pathogenesis, which include dysregulated lung inflammation, neutrophilia, recruitment of interleukin 17A (IL -17A) expressing CD4⁺T cells (Th17), and the paucity of lung regulatory T cells (Tregs), have also been described in SM-lung. Areas covered: A literature search was performed using the MEDLINE, EMBASE, and Web of Science databases inclusive of all literature prior to and including May 2017. Expert commentary: Here we review some of the recent findings that suggest a role for Th17 cell-mediated inflammatory changes associated with pulmonary complications in SM-lung and suggest new therapeutic approaches that could potentially alter disease progression with immune modulating biologics that can restore the lung Th17/Treg balance.

Progressive delayed respiratory complications of sulfur mustard poisoning in 43 Iranian veterans, three decades after exposure

The most common delayed complication of sulfur mustard (SM) poisoning has been observed in the respiratory tracts. It was thus aimed to investigate the delayed respiratory complications in SM-exposed patients around 25 years before the study. Forty-three veterans with more than 25% disability of due to SM poisoning were investigated. Clinical examinations as well as pulmonary function test (PFT) were performed. High-resolution computed tomography (HRCT) of the lungs was done as clinically indicated. Triad of chronic cough, dyspnea, and expectoration were the most common symptoms that were recorded in 88.2%, 88.2%, and 64.7% of the patients, respectively. PFT abnormalities were detected in 44.18% of the patients. Restrictive pattern was the most common (41.86%), while pure obstructive pattern did not detect at all. Mixed pattern was significantly correlated with higher disability percentages among the veterans ( p < 0.001). Significant reverse correlation between the disability percentages and forced expiratory volume in 1 s/forced vital capacity ratio was obtained ( p = 0.010, r = −0.389). Air trapping was the most common abnormality in HRCTs (50%). Bronchiectasis (25%), pulmonary fibrosis (25%), and ground-glass attenuation (16.66%) were other common HRCT findings. Comparing with the previous studies on these patients, more restrictive and mixed pattern were observed. Moreover, bronchiolitis, bronchiectasis, and lung fibrosis were the main pathological findings in these patients.

An evidence-based review of the genotoxic and reproductive effects of sulfur mustard

Sulfur mustard (SM) is a chemical warfare agent which is cytotoxic in nature, and at the molecular level, SM acts as DNA alkylating agent leading to genotoxic and reproductive effects. Mostly, the exposed areas of the body are the main targets for SM; however, it also adversely affects various tissues of the body and ultimately exhibits long-term complications including genotoxic and reproductive effects, even in the next generations. The effect of SM on reproductive system is the reason behind male infertility. The chronic genotoxic and reproductive complications of SM have been observed in the next generation, such as reproductive hormones disturbances, testicular atrophy, deficiency of sperm cells, retarded growth of sperm and male infertility. SM exerts toxic effects through various mechanisms causing reproductive dysfunction. The key mechanisms include DNA alkylation, production of reactive oxygen species (ROS) and nicotinamide adenine dinucleotide (NAD) depletion. However, the exact molecular mechanism of such long-term effects of SM is still unclear. In general, DNA damage, cell death and defects in the cell membrane are frequently observed in SM-exposed individuals. SM can activate various cellular and molecular mechanisms related to oxidative stress (OS) and inflammatory responses throughout the reproductive system, which can cause decreased spermatogenesis and impaired sperm quality via damage to tissue function and structure. Moreover, the toxic effects of SM on the reproductive system as well as the occurrence of male infertility among exposed war troopers in the late exposure phase is still uncertain. The chronic effects of SM exposure in parents can cause congenital defects in their children. In this review, we aimed to investigate chronic genotoxic and reproductive effects of SM and their molecular mechanisms in the next generations.

NMR spectroscopy-based metabolomic study of serum in sulfur mustard exposed patients with lung disease

Sulfur mustard (SM) is a vesication chemical warfare agent for which there is currently no antidote. Despite years of research, there is no common consensus about the pathophysiological basis of chronic pulmonary disease caused by this chemical warfare agent. In this study, we combined chemometric techniques with nuclear magnetic resonance (NMR) spectroscopy to explore the metabolic profile of sera from SM-exposed patients. A total of 29 serum samples obtained from 17 SM-injured patients, and 12 healthy controls were analyzed by Random Forest. Increased concentrations of seven amino acids, glycerol, dimethylamine, ketone bodies, lactate, acetate, citrulline and creatine together with the decreased very low-density lipoproteins (VLDL) levels were observed in patients compared with control subjects. Our study reveals the metabolic profile of sera from SM-injured patients and indicates that NMR-based methods can distinguish these patients from healthy controls.

The effect of vitamin E on lung pathology in sulfur mustard-exposed guinea pigs

Pulmonary complications of exposure to sulfur mustard (SM) gas range from no effect or mild symptoms to severe bronchial stenosis. In the present study, the protective effect of vitamin E on the lung inflammation of SM-exposed guinea pigs was examined. Guinea pigs ( n = 5 for each group) were exposed to ethanol (control group), 40 mg/m3 inhaled SM (SME group), SME treated with vitamin E (SME + E), SME treated with dexamethasone (SME + D), and SME treated with both treatments (SME + E + D). Pathological evaluation of the lung was done 14 days postexposure. The epithelial desquamation of trachea and other pathologic changes in the lung of the SME group were significantly higher than those in the control group. Furthermore, the pathological changes of trachea and lung in the SME + E and SME + E + D groups were significantly improved compared with those of SME group. In addition, the pathological changes of trachea and lung of SME + E and SME + E + D animals were significantly less than those of SME + D group.

Sulfur mustard inhalation: mechanisms of injury, alteration of coagulation, and fibrinolytic therapy

Acute lung injury due to sulfur mustard (SM) inhalation causes the formation of airway fibrin casts that obstruct airways at multiple levels, leading to acute respiratory failure and death. These pathophysiological effects are seen in rodent models of acute SM vapor inhalation, as well as in human victims of acute SM inhalation. In rat models, the initial steps in activation of the coagulation system at extravascular sites depend on tissue factor (TF) expression by airway cells, especially in the microparticle fraction, and these effects can be inhibited by TF pathway inhibitor protein. Not only does the procoagulant environment of the acutely injured lung contribute to airway cast formation, but these lesions persist in airways because of the activation of multiple antifibrinolytic pathways, including plasminogen activator inhibitor-1, thrombin-activatable fibrinolysis inhibitor, and α2-antiplasmin. Airway administration of tissue plasminogen activator can overwhelm these effects and save lives by preventing fibrin-dependent airway obstruction, gas-exchange abnormalities, and respiratory failure. In human survivors of SM inhalation, fibrotic processes, including bronchiolitis obliterans and interstitial fibrosis of the lung, are among the most disabling chronic lesions. Antifibrotic therapies may prove useful in preventing either or both of these forms of chronic lung damage.

Analytic Reviews: Management of Patients Exposed to Biological and Chemical Warfare Agents

Biological and chemical weapons have been used for waging war since the dawn of recorded history. Recently, these agents have been used on civilian populations by terrorist groups. Terrorist attacks using biological or chemical weapons have far-reaching implications, as they cause widespread fear, anxiety, and panic among the public. Biological agents have particular appeal for use in terrorist attacks because they are reasonably easy to acquire, are inexpensive to produce, and have the potential to affect large populations of people. Biological agents are selected based on their toxicity, ease of production and stability, and ability to be dispersed in respirable aerosols. The most common biological agents that have been weaponized include anthrax, plague, tularemia, botulism toxin, and smallpox. Chemical agents are more expensive and more difficult to manufacture and deploy and are therefore more likely to be used in conventional warfare. Mustard gas and nerve agents are the favored chemical agents of mass destruction.

Emerging targets for treating sulfur mustard-induced injuries

Sulfur mustard (SM; bis-(2-chlororethyl) sulfide) is a highly reactive, potent warfare agent that has recently reemerged as a major threat to military and civilians. Exposure to SM is often fatal, primarily due to pulmonary injuries and complications caused by its inhalation. Profound inflammation, hypercoagulation, and oxidative stress are the hallmarks that define SM-induced pulmonary toxicities. Despite advances, effective therapies are still limited. This current review focuses on inflammatory and coagulation pathways that influence the airway pathophysiology of SM poisoning and highlights the complexity of developing an effective therapeutic target.

Mustard vesicant-induced lung injury: Advances in therapy

Most mortality and morbidity following exposure to vesicants such as sulfur mustard is due to pulmonary toxicity. Acute injury is characterized by epithelial detachment and necrosis in the pharynx, trachea and bronchioles, while long-term consequences include fibrosis and, in some instances, cancer. Current therapies to treat mustard poisoning are primarily palliative and do not target underlying pathophysiologic mechanisms. New knowledge about vesicant-induced pulmonary disease pathogenesis has led to the identification of potentially efficacious strategies to reduce injury by targeting inflammatory cells and mediators including reactive oxygen and nitrogen species, proteases and proinflammatory/cytotoxic cytokines. Therapeutics under investigation include corticosteroids, N-acetyl cysteine, which has both mucolytic and antioxidant properties, inducible nitric oxide synthase inhibitors, liposomes containing superoxide dismutase, catalase, and/or tocopherols, protease inhibitors, and cytokine antagonists such as anti-tumor necrosis factor (TNF)-α antibody and pentoxifylline. Antifibrotic and fibrinolytic treatments may also prove beneficial in ameliorating airway obstruction and lung remodeling. More speculative approaches include inhibitors of transient receptor potential channels, which regulate pulmonary epithelial cell membrane permeability, non-coding RNAs and mesenchymal stem cells. As mustards represent high priority chemical threat agents, identification of effective therapeutics for mitigating toxicity is highly significant.

Long-term pulmonary complications of chemical weapons exposure in former poison gas factory workers

CONTEXT

Sulfur mustard (SM) and lewisite are vesicant chemical warfare agents that can cause skin blistering and chronic lung complications. During 1929-1945, a Japanese factory produced poisonous gases, which included SM, lewisite and other chemical weapons. The aim of this study was to investigate the chest computed tomography (CT) findings among long-term survivors who worked at this factory.

METHODS

During 2009-2012, we evaluated chest CT findings from 346 long-term survivors who worked at the poison gas factory. Skin lesions were used as an indicator of significant exposure to vesicant agents.

RESULTS

Among the 346 individuals, 53 (15%) individuals experienced skin lesions while working at the factory, and chest CT revealed abnormal findings in 179 individuals (52%). Emphysema was the most common CT finding and was observed in 75 individuals (22%), while honeycombing was observed in 8 individuals (2%). Emphysema and honeycombing were more prevalent among individuals with skin lesions, compared to individuals without skin lesions. Multivariate analyses revealed significant associations between the presence of emphysema and skin lesions (p = 0.008). Among individuals who never smoked, individuals with skin lesions (n = 26) exhibited a significantly higher rate of emphysema, compared to individuals without skin lesions (n = 200) (35% versus 7%, respectively; p < 0.001).

CONCLUSION

Among the long-term survivors who worked at the poison gas factory, a history of skin lesions was associated with the presence of emphysema, even among never smokers, which suggests that emphysema might be a long-term complication of exposure to chemical warfare agents.

Pro-oxidant-antioxidant balance in Iranian veterans with sulfur mustard toxicity and different levels of pulmonary disorders

OBJECTIVE

Sulfur mustard (SM) is a strong alkylating agent that primarily targets the skin, eye and lung. The current study evaluated the pro-oxidant-antioxidant balance (PAB) assay in human serum of SM-exposed patients.

DESIGN AND METHODS

sera of 35 SM-exposed patients and 19 healthy volunteers were recruited. Both groups had nonsmoker and nonalcoholic people with no diseases such as diabetes, heart disease and other pulmonary diseases (COPD because of smoking, asthma and so on). All patients had documented exposure to SM. The PAB was measured.

RESULTS

SM-exposed patients with normal values for pulmonary function test and severe obstructive pulmonary disease demonstrated a significant increase in PAB value in compared with healthy volunteers (the PAB values in healthy volunteers, normal and severe patients were 48.74 ± 21.07 HK, 101.45 ± 32.68 HK and 120.23 ± 31.55 HK, respectively). However, the level of oxidation is not related to the severity of disease defined by spirometry findings. A significant negative correlation was established between the PAB value and FEV1.

CONCLUSIONS

The increased PAB value in chemical casualties showed that these patients are exposed to oxidative stress.

Respiratory effects of sulfur mustard exposure, similarities and differences with asthma and COPD

CONTEXT

Previous research has found relationships between sulfur mustard (SM) toxicity and its adverse effects.

OBJECTIVE

SM is highly toxic to the respiratory system, leading to hacking cough, rhinorrheachest tightness, acute pharyngitis and laryngitis, chronic bronchitis and lung fibrosis. In this review, based on the scientific literature, we provide an updated summary of information on SM exposures and their differences with asthma and COPD.

METHOD

Information of this review was obtained by searching Medline/PubMed, ScienceDirect, Scopus, Google Scholar, ISI Web of Knowledge and Chemical Abstracts.

RESULTS

SM exposure can decrease pulmonary function tests (PFTs) values. In addition, inflammatory cell accumulation in the respiratory tract and increased expression of some pro-inflammatory cytokines including tumor necrosis factor-α (TNFα), IL-1a, IL-1β, and reactive oxygen radicals due to SM exposure have been shown. Matrix metalloproteinase (MMP) which degrade extracellular matrix proteins, contributing to inflammatory cell recruitment, tissue injury and fibrosis are also up-regulated in the lung after SM exposure. In the lung, SM exposure also can cause serious pathological changes including airway inflammation, parenchymal tissue destruction and airway obstruction which can lead to asthma or chronic obstructive pulmonary disease (COPD). Following SM poisoning, DNA damage, apoptosis and autophagy are observed in the lung along with the increased expression of activated caspases and DNA repair enzymes.

CONCLUSION

In the present article, respiratory symptoms, changes in PFTs, lung pathology and lung inflammation due to SM exposure and the similarities and differences between them and those observed in asthma and COPD were reviewed.