RESUMO
As a mineral material widely used in life, chrysotile is a public health concern for its fibrogenicity and carcinogenicity. Currently, more than 50 countries have completely banned the import and use of chrysotile, but China is still the world's largest consumer and second largest producer of chrysotile, with a large occupationally exposed population. Investigations have shown that chrysotile miners are significantly more likely to develop pulmonary fibrosis, lung cancer, and mesothelioma than workers in other occupations. Chrysotile-induced cancers generally have a decades-long latency period and are difficult to diagnose and treat in a timely manner. Therefore, the cancer fatality due to chrysotile exposure is significant and is a leading contributor to occupational cancer death. Epithelial mesenchymal transition is a key step in the biological processes of chronic inflammation, fibrosis, carcinogenesis, and cancer metastasis in tissues and organs, also plays an important role in pulmonary fibrosis, lung cancer, and other diseases due to chrysotile exposure. This paper summarized the mechanisms of chrysotile inducing epithelial interstitial transition from dynamics of inflammatory factors, mitogen-activated protein kinase pathways, oxidative stress, and other biological pathways, and proposed possible research directions for further study on chrysotile-induced epithelial mesenchymal transition, aiming to provide a reliable basis and reference for in-depth research on pulmonary fibrosis, lung cancer, and other diseases due to chrysotile exposure.
RESUMO
BACKGROUND@#The presence of fibrosis is a criterion for subtype classification in the newly updated hypersensitivity pneumonitis (HP) guidelines. The present study aimed to summarize differences in clinical characteristics and prognosis of non-fibrotic hypersensitivity pneumonitis (NFHP) and fibrotic hypersensitivity pneumonitis (FHP) and explore factors associated with the presence of fibrosis.@*METHODS@#In this prospective cohort study, patients diagnosed with HP through a multidisciplinary discussion were enrolled. Collected data included demographic and clinical characteristics, laboratory findings, and radiologic and histopathological features. Logistic regression analyses were performed to explore factors related to the presence of fibrosis.@*RESULTS@#A total of 202 patients with HP were enrolled, including 87 (43.1%) NFHP patients and 115 (56.9%) FHP patients. Patients with FHP were older and more frequently presented with dyspnea, crackles, and digital clubbing than patients with NFHP. Serum levels of carcinoembryonic antigen, carbohydrate antigen 125, carbohydrate antigen 153, gastrin-releasing peptide precursor, squamous cell carcinoma antigen, and antigen cytokeratin 21-1, and count of bronchoalveolar lavage (BAL) eosinophils were higher in the FHP group than in the NFHP group. BAL lymphocytosis was present in both groups, but less pronounced in the FHP group. Multivariable regression analyses revealed that older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors for the development of FHP. Twelve patients developed adverse outcomes, with a median survival time of 12.5 months, all of whom had FHP.@*CONCLUSIONS@#Older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors associated with the development of FHP. Prognosis of patients with NFHP was better than that of patients with FHP. These results may provide insights into the mechanisms of fibrosis in HP.