Paraseptal Emphysema in Indium Lung: Tracing the Pathological Footprints of Chronic Exposure.

Indium lung is an occupational lung disease caused by exposure to indium-tin-oxide (ITO) dust. Compared to other occupational lung diseases, indium lung has a shorter latency period and the respiratory status continues to worsen even after exposure to the work environment improves. Paraseptal emphysema which affects mainly the subpleural area is seen on chest images obtained via computed tomography (CT), regardless of the smoking history. However, the pathogenesis of emphysema in indium lung is still unclear. Therefore, we re-evaluated the pathology of three previously reported cases of indium lung. Paraseptal emphysema was observed in both smokers and nonsmokers. Obstructive respiratory impairment worsened over time in the cases with paraseptal emphysema. Many alveolar walls were destroyed independent of the presence or absence of emphysetamous changes or fibrosis. Moreover, bronchiolitis was found to be less common in indium lung than in asbestosis (the most common occupational lung disease) or common cases of chronic obstructive pulmonary disease caused by smoking. It has been shown that ITO causes protease anti-protease imbalance, oxidant-antioxidant imbalance, and continuous, abnormal inflammation (the three major causes of emphysema). In addition, nano-sized ITO is less likely to be trapped in the upper airways and may easily reach the subpleural alveoli. Furthermore, ITO may continue to cause sustained tissue injury at the alveolar level potentially resulting in emphysema. Further studies are needed to elucidate the detailed pathogenesis of indium lung by comparing it with other occupational lung diseases.

A case report of Indium lung with progressive emphysema and fibrosis underwent lung unilateral transplantation 20 years after the end of the exposure.

BACKGROUND: Indium lung is characterized by interstitial pneumonia and/or emphysema which occurs in indium-tin oxide (ITO) workers. Indium lung is now known to progress after stopping exposure to ITO, but the long-term influences of ITO remain unclear. CASE PRESENTATION: Forty seven years old, a never-smoker, who had been engaged in an ITO manufacturing process for 8 years. Emphysema was indicated by the medical check-up for ex-ITO workers, and he was diagnosed with indium lung. He underwent partial lung resections for pneumothorax two times, and obstructive pulmonary dysfunction had progressed through the years. He underwent right single lung transplant 20 years after ITO exposure. Pathologically, his lung showed severe distal acinar emphysema and honeycomb change. Fibrosis and destruction of the lung tissue significantly progressed compared to the previous partial resections. Scanning electron microscopy combined with energy dispersive spectroscopy revealed that the deposited particles contained indium and tin. After the transplantation, his respiratory function was improved. CONCLUSIONS: In this case, ITO resided in the lung tissue for 20 years, and lung tissue destruction kept progressing. Careful medical follow-up is recommended for ITO-workers even if they are asymptomatic.

Progression of Smoking-Induced Emphysema in a Case with Indium Lung.

Recently, it has become clear that inhaled indium-tin oxide causes emphysematous as well as interstitial changes in the lung. Here, we present a 59-year-old male ex-smoker, quitting smoking at the age of 55. He had been engaged in indium-tin oxide processing from 27 to 37 years of age, with 22 years having passed since the final exposure to indium. He was found to have a high serum indium concentration and Krebs von den Lungen-6 (KL-6). Furthermore, bilateral centrilobular emphysema was recognized in high-resolution computed tomography (HRCT). After transferring jobs to a non-indium-tin oxide section, KL-6 returned to a normal level within 4 years, whereas neither serum indium concentration nor emphysema had decreased to normal despite 22 years having passed since the exposure ended. At the age of 59, a thoracoscopic lung biopsy was performed to assess the contribution of smoking and that of indium to the lung destruction. The pathological findings demonstrated cholesterol granulomas with the accumulation of macrophages and multinucleated giant cells that had phagocytosed particles. Together with the typical findings of indium lung, fibrotic and emphysematous changes were observed. The elemental analysis of the biopsied specimens revealed excessive deposition of indium throughout the airways, interstitial spaces and alveoli. The pathological findings of this case may be the result of two kinds of pulmonary damage, i.e., smoking and indium. This report indicates that occupationally-inhaled indium could remain in the lung for as long as 22 years and continue to insult the lung tissue with inflammation caused by smoking.

Response to pembrolizumab in a patient with primary lung adenocarcinoma originated from indium lung.

BACKGROUND: Indium is a metal used as a compound called indium-tin oxide for liquid crystal display. Its inhalation causes lung toxicity, resulting in a new occupational lung disease called indium lung. Although the carcinogenicity of indium has been reported in an animal model, its carcinogenicity in humans is unknown. CASE PRESENTATION: This is the first reported case of a primary lung cancer originating from indium lung. In this report, we describe a 46-year-old man with interstitial pneumonia-type indium lung diagnosed 16 years ago. The initial symptom was left chest pain, and computed tomography showed a mass adjacent to the aorta with left pleural effusion. Specimens collected using video-assisted thoracoscopy revealed an adenocarcinoma with a high expression of programmed cell death-ligand 1 (cT4N0M1a stage IVA). Although the lesions showed a remarkable aggressive nature, the patient benefited from pembrolizumab, a monoclonal antibody against programmed cell death 1, which was used as second-line therapy for 2 years. CONCLUSIONS: It is important for clinicians to be aware of lung cancer development in indium-exposed workers or in patients with indium lung, as this could have an aggressive behavior. Treatment with immune checkpoint inhibitors is an option even in patients with interstitial pneumonia-type indium lung.

Indium Lung: Discovery, Pathophysiology and Prevention.

Indium is mainly used as indium-tin oxide (ITO), which has a unique character of transparency, and is a requisite in making liquid crystal displays. Pulmonary toxicity of indium compounds in humans were not recognized until the last 2 decades. Several initial human cases of indium-related lung disease, named indium lung, were reported in Japan, with their main pathologic findings being interstitial pneumonia, emphysema and cholesterol crystals-containing granulomas. In 2010, three cases with alveolar proteinosis were reported from the United States and China. As of March 2019, more than 10 cases of interstitial pneumonia-dominant indium lung have been reported. Cross-sectional studies in indium workers indicate that the serum indium concentration (sIn) is closely related to the exposure period, the extent of interstitial as well as emphysematous changes of the lung on high-resolution computed tomography (HRCT) and serum biomarkers of interstitial pneumonia, including KL-6 and surfactant protein-D (SP-D). Longitudinal studies have shown it is possible to reduce the sIn as well as the interstitial shadows on HRCT; however, emphysematous lesions increased progressively in heavily exposed workers, even after cessation of exposure. Early detection is required to prevent irreversible changes. The first case of lung cancer associated with indium lung developed in a nonsmoking ex-worker. He had been diagnosed with indium lung and stopped working in indium processing 17 years before. This suggested there is a need for appropriate screening to detect for complications of lung cancer at early stages for those with indium lung.

Circulating Anti-Coatomer Protein Complex Subunit Epsilon (COPE) Autoantibodies as a Potential Biomarker for Cardiovascular and Cerebrovascular Events in Patients with Obstructive Sleep Apnea.

STUDY OBJECTIVES: Although moderate to severe obstructive sleep apnea (OSA) is an independent risk factor for severe arteriosclerotic diseases such as cardiovascular disease (CVD) and stroke, the development of atherosclerosis-related diseases cannot yet be predicted in patients with OSA. In a pilot study, we identified autoantibodies against the coatomer protein complex, subunit epsilon [circulating anti-coatomer protein complex subunit epsilon autoantibody (COPE-Ab)], a cytosolic complex that mediates protein transport in the Golgi compartment, as a potential novel biomarker of atherosclerosis. This study aimed to evaluate whether COPE-Ab levels had an association with cardiovascular and cerebrovascular events in patients with OSA. METHODS: Eighty-two adult patients with a diagnosis of OSA via polysomnography and 64 healthy donors were studied. Serum COPE-Ab levels were measured using an amplified luminescence proximity homogeneous assay. Then, clinical factors related to atherosclerosis were evaluated with respect to COPE-Ab levels. RESULTS: Significant differences in COPE-Ab levels were observed in terms of OSA severity. COPE-Ab levels were significantly higher in patients with OSA and also CVD and/or stroke, hypertension, and a high body mass index. Univariate and multivariate logistic regression analyses of patients with OSA identified elevated COPE-Ab level as a significant predictor of CVD and/or stroke. CONCLUSIONS: An elevated COPE-Ab level may be a potential predictor of the risks of cardiovascular and cerebrovascular events in patients with OSA. Therefore, patients with higher COPE-Ab levels may require more careful and intensive treatment. COMMENTARY: A commentary on this article appears in this issue on page 361.

High levels of indium exposure relate to progressive emphysematous changes: a 9-year longitudinal surveillance of indium workers.

BACKGROUND: During the last decade it has been clarified that the inhalation of indium compounds can evoke alveolar proteinosis, cholesterol granuloma, pulmonary fibrosis and emphysema. In this study, we aimed to elucidate the characteristics and time course of pulmonary disorders among indium workers using comprehensive pulmonary examinations at an indium-processing factory. METHODS: Data for 84 male workers who underwent the examinations for nine consecutive years from 2002 to 2010 were analysed regarding their symptoms, serum indium concentration (sIn), serum markers of interstitial pneumonia, pulmonary function test parameters and high-resolution CT (HRCT) findings of the lungs. RESULTS: In association with improvements in the work environment and work practice, the sIn levels decreased with significant reductions in the KL-6 and surfactant protein D (SP-D) levels. Regarding the HRCT findings, the interstitial lesions regressed partially, whereas emphysematous lesions increased progressively in the workers with high sIn values. FEV1/FVC decreased with the years and the rate of decrease was significantly greater in those with high sIn. The biological half-life of sIn was estimated to be 8.09 years. CONCLUSIONS: The present findings suggest that the sIn, SP-D, KL-6 levels and radiological interstitial changes can be reduced in indium workers by alleviating exposure to indium, whereas emphysematous lesions can progress among those with a history of heavy exposure.