Outcomes after lung transplantation for patients with occupational lung diseases

Silicosis-Allergic Bronchopulmonary Aspergillosis Overlap-A Rare Duet!

Silicosis is a progressive pneumoconiosis caused by inhalation of crystalline silica dust commonly seen in workers of construction sites, flour mills, and mining. Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus fumigatus antigens commonly encountered in patients with asthma and cystic fibrosis. We report a case of 60-year-old flour mill worker presented with clinico-radiological features of silicosis; further evaluation was found to have an overlap of ABPA in view of severe atopic symptoms. We describe a rare duet of silicosis with ABPA overlap.

Human embryonic stem cell-derived mesenchymal stem cell secretome reverts silica-induced airway epithelial cell injury by regulating Bmi1 signaling

Silicosis is an irreversible chronic pulmonary disease caused by long-term inhalation and deposition of silica particles, which is currently incurable. The exhaustion of airway epithelial stem cells plays a pathogenetic role in silicosis. In present study, we investigated therapeutic effects and potential mechanism of human embryonic stem cell (hESC)-derived MSC-likes immune and matrix regulatory cells (IMRCs) (hESC-MSC-IMRCs), a type of manufacturable MSCs for clinical application in silicosis mice. Our results showed that the transplantation of hESC-MSC-IMRCs led the alleviation of silica-induced silicosis in mice, accompanied by inhibiting epithelia-mesenchymal transition (EMT), activating B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) signaling and airway epithelial cell regeneration. In consistence, the secretome of hESC-MSC-IMRC exhibited abilities to restore the potency and plasticity of primary human bronchial epithelial cells (HBECs) proliferation and differentiation following the SiO2 -induced HBECs injury. Mechanistically, the secretome resolved the SiO2 -induced HBECs injury through the activation of BMI1 signaling and restoration of airway basal cell proliferation and differentiation. Moreover, the activation of BMI1 significantly enhanced the capacity of HBEC proliferation and differentiation to multiple airway epithelial cell types in organoids. Cytokine array revealed that DKK1, VEGF, uPAR, IL-8, Serpin E1, MCP-1 and Tsp-1 were the main factors in the hESC-MSC-IMRC secretome. These results demonstrated a potential therapeutic effect of hESC-MSC-IMRCs and their secretome for silicosis, in part through a mechanism by activating Bmi1 signaling to revert the exhaustion of airway epithelial stem cells, subsequentially enhance the potency and plasticity of lung epithelial stem cells.

Clinical outcomes and survival following lung transplantation for work-related lung disease: a single-center retrospective cohort study

BACKGROUND

Patients with work-related lung disease (WRLD) are at increased risk of death caused by severe lung tissue damage and fibrosis. This study aimed to assess the clinical outcomes of lung transplantation (LTx) for WRLD and compare the results of LTx between WRLD and idiopathic pulmonary fibrosis (IPF).

METHODS

This single-center retrospective cohort study reviewed the clinical data of patients who underwent LTx for WRLD or IPF at our hospital between January 2015 and December 2021. Cumulative survival rates after LTx were estimated using the Kaplan-Meier method.

RESULTS

The final analysis included 33 cases of WRLD and 91 cases of IPF. The 33 WRLD patients consisted of 19 (57.6%) cases of silicosis, 8 (24.2%) cases of coal workers' pneumoconiosis, 3 (9.09%) cases of asbestosis, and 3 (9.09%) cases of other WRLD. Pneumothorax as an indication for LTx was significantly more common in the WRLD group than in the IPF group (51.5% vs. 2.2%, P < 0.001). There was no significant difference in the 5-year cumulative survival rate between the WRLD patients and the IPF patients (66.6% vs. 56.7%, P = 0.67). There was no significant difference in the best performance of exercise capacity and lung function between the two groups at 1 year post-transplant.

CONCLUSIONS

LTx had similar survival outcomes and lung function for WRLD and IPF patients. Pneumothorax was the primary indication for lung transplantation in WRLD.

Lung transplantation for interstitial lung disease

Lung transplantation (LTx) can be a life-extending treatment option for patients with advanced and/or progressive fibrotic interstitial lung disease (ILD), especially idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis, sarcoidosis and connective tissue disease-associated ILD. IPF is now the most common indication for LTx worldwide. Several unique features in patients with ILD can impact optimal timing of referral or listing for LTx, pre- or post-transplant risks, candidacy and post-transplant management. As the epidemiology of LTx and community practices have evolved, recent literature describes outcomes and approaches in higher-risk candidates. In this review, we discuss the unique and important clinical findings, course, monitoring and management of patients with IPF and other progressive fibrotic ILDs during pre-LTx evaluation and up to the day of transplantation; the need for co-management with clinical experts in ILD and LTx is emphasised. Some post-LTx complications are unique in these patient cohorts, which require prompt detection and appropriate management by experts in multiple disciplines familiar with telomere biology disorders and infectious, haematological, oncological and cardiac complications to enhance the likelihood of improved outcomes and survival of LTx recipients with IPF and other ILDs.

Hesperetin attenuates silica-induced lung injury by reducing oxidative damage and inflammatory response

Oxidative stress and the inflammatory response are two important mechanisms of silica-induced lung injury. Hesperetin (HSP) is a natural flavonoid compound that is found in citrus fruits and has been indicated to exhibit strong antioxidant and anti-inflammatory properties. The current study evaluated the protective effect of HSP on lung injury in rats exposed to silica. The results indicated that the degree of alveolitis and pulmonary fibrosis in the HSP-treated group was significantly decreased compared with the silica model group. The content of hydroxyproline (HYP) was also revealed to decrease overall in the HSP treated group compared with the silica model group, indicating that the degree of pulmonary fibrosis was decreased compared with the silica model group. The present study also demonstrated that HSP reduced oxidation levels of malondialdehyde (MDA) and increased the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX). Total antioxidant capacity (T-AOC) was also increased following HSP treatment, indicating that HSP can alleviate oxidative stress in the lung tissue of silica-exposed rats. In addition, HSP was revealed to inhibit the synthesis and secretion of fibrogenic factor TGF-β1, reduce the production of pro-inflammatory cytokines IL-1β, IL-4, TNF-α and increase the levels of anti-inflammatory factors IFN-γ and IL-10. The current study demonstrated that HSP can effectively attenuate silica-induced lung injury by reducing oxidative damage and the inflammatory response.

Risk Factors for Mortality in Denim Sandblasters Silicosis: Selecting Candidate for Lung Transplantation

OBJECTIVE

This study aimed to review the risk factors for silicosis together with survival analysis and a perspective for lung transplantation with data from a single center.

MATERIAL AND METHODS

We reviewed the medical records of denim sandblasters who were referred to our center between January 2006 and December 2011 and evaluated 219 patients with a history of denim sandblasting with a minimum follow-up period of 5 years until 2016. We analyzed several personal and occupational features, together with functional and radiologic data.

RESULTS

Of the 219 denim sandblasters, 107 (49%) had been diagnosed with silicosis. In the logistic regression analysis, the duration of exposure was the only independent risk factor for the development of silicosis, indicating a 9% increased risk of silicosis for every month of exposure (p<0.001; odds ratio 1.09; 95% confidence interval 1.050-1.132). Of the patients, 7 (3%) died. A forced expiratory volume in the first second of <44% and a forced vital capacity of <47% were associated with an increased risk of mortality. Mortality was significantly higher in the international labor office category 3 patients, and 5-year survival rates of patients with A, B, and C lung opacities were 88%, 67%, and 25%, respectively.

CONCLUSION

Silicosis still kills young workers. Severe radiologic involvement and decreased lung volumes are related to mortality, and lung transplantation is the only therapeutic option.

A novel pathophysiological classification of silicosis models provides some new insights into the progression of the disease

Silicosis is caused by massive inhalation of silica-based particles, which leads to pulmonary inflammation, pulmonary fibrosis and lung dysfunction. Currently, the pathophysiological process of silicosis has not been well studied. Here, we defined the progression of silicosis as four stages by unsupervised clustering analysis: normal stage, inflammatory stage, progressive stage and fibrotic stage. Specifically, in normal stage, the lung function was normal, and no inflammation or fibrosis was detected in the lung tissue. Inflammatory stage showed a remarkable pulmonary inflammation but mild fibrosis and lung dysfunction. In progressive stage, significant lung dysfunction was observed, while pulmonary inflammation and fibrosis continued to deteriorate. Fibrotic stage revealed the most severe pulmonary fibrosis and lung dysfunction but no significant deterioration in inflammation. Since the common features were founded in both silicosis patients and rodents, we speculated that the pathophysiological processes of silicosis in patients might be similar to the rodents. Collectively, our new classification identified the process of silicosis, clarified the pathophysiological features of each stage, and provided some new insights for the progression of the disease.

Current Review of Pneumoconiosis Among US Coal Miners

PURPOSE OF REVIEW

This review summarizes recent research on pneumoconiosis in coal workers following the identification of the resurgence of this disease among US coal miners in the early 2000s. We describe the impact of this research and how this has led to increased public attention, benefitting affected miners.

RECENT FINDINGS

The latest research shows that the prevalence of pneumoconiosis, including progressive massive fibrosis, continues to increase, especially in central Appalachia. Contributing factors may include mining of thin coal seams or cutting rock to access coal, which may expose miners to coal mine dust with a higher content of silica and silicates than in the past. The impact of recently implemented changes, such as the reduced occupational exposure limit for respirable coal mine dust and the introduction of continuous personal dust monitors, will likely take years to appropriately evaluate.