Pulmonary involvement in systemic sclerosis: exploring cellular, genetic and epigenetic mechanisms

Systemic sclerosis associated respiratory involvement: Scopus-based analysis of articles in 2013-2022

BACKGROUND

Systemic sclerosis (SSc), a complex autoimmune disorder, manifests as a convergence of rheumatologic, dermatologic, and pulmonary challenges. Among the severe complications contributing to morbidity and mortality are SSc Associated Interstitial Lung Disease (SSc-ILD) and pulmonary hypertension. Over the past decade, research on pulmonary involvement in SSc has intensified, leading to a heightened understanding of its pathogenesis, diagnostic methods, and therapeutic strategies.

AIM

This study aims to provide a data-driven overview of the current state of systemic sclerosis research, identifying emerging trends and fostering informed decisions regarding resource allocation and research priorities.

METHODS

A literature search was conducted in the Scopus database, using MESH keywords such as "systemic sclerosis" AND "lungs" OR "pulmonary hypertension" OR "interstitial lung disease". After applying exclusion criteria, a thorough analysis was performed, considering factors such as document category, authorship, journal source, citation frequency, country of publication, language, and keywords. The bibliometric analysis utilized Scopus as the preferred database, leveraging its extensive coverage, user-friendly interface, and commitment to data accuracy. Visual networks were constructed using VOSviewer software to map the relationships between keywords, countries, and authors. Altmetric Attention Scores (AAS) were employed to assess the social impact of articles.

RESULTS

The analysis revealed a total of 2538 scholarly items, with 55.7% identified as open access. The USA (n = 532), Italy (n = 458), France (n = 304), Japan (n = 271), and the UK (n = 236) emerged as primary contributors, with English being the predominant language. A notable upward tendency in annual publication and citation scores indicated sustained interest and relevance in SSc-ILD research. The top journals, including Rheumatology United Kingdom, Clinical and Experimental Rheumatology, Clinical Rheumatology, Arthritis and Rheumatology, and Journal of Rheumatology, played a pivotal role in scholarly output. Original Articles (n = 1795; 70.7%) constituted the majority of publications, followed by Reviews, Letters, Notes, and Editorials. The analysis of publication impact within different scholarly formats revealed varying citation patterns, with Original Articles and Reviews leading in influence. The identification of influential research hubs and key contributors provided insights into collaborative efforts and geographic distribution. A strong correlation (rho = 0.612, p < 0.001) was observed between the quantity of Mendeley readers and the citations received by scholarly articles.

CONCLUSION

This bibliometric analysis offers a comprehensive overview of SSc-ILD research, highlighting its dynamic and interdisciplinary nature. The surge in publications, citation scores, and the identification of key contributors underscore the continued relevance and impact of this field. The nuanced relationships between social attention and scientific recognition, as revealed by Mendeley readership and AAS, contribute to a deeper understanding of the multifaceted nature of scholarly impact.

Angiotensin-converting enzyme 1 gene polymorphisms in patients with systemic sclerosis-associated interstitial lung disease: a single centre retrospective observational study

Angiotensin-converting enzyme (ACE) 1 gene polymorphisms have been associated with vascular permeability, alveolar endothelial dysfunction and fibroblast proliferation and have been studied in pulmonary diseases such as COPD and idiopathic pulmonary fibrosis. Similar mechanisms of ACE 1 polymorphisms have been seen in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD). We are presenting a retrospective observational study in patients with SSc-ILD and analysing the association of ACE 1 gene polymorphisms (DD, II and ID) with the features of SSc, changes in pulmonary function tests (PFTs) and lung HRCT over three different periods of time (at the time of the diagnosis, 5 and 10 years after the diagnosis). The aim of the study was to determine whether ACE 1 gene polymorphisms have an effect on the severity of SSc-ILD. We found no statistically significant differences in the development and severity of SSc-ILD and changes in PFTs between subgroups of ACE 1 gene polymorphism over the analysed periods (at the time of diagnosis HRCT changes p = 0.270, FEV1 p = 0.483, FVC p = 0.497, DLco p = 0.807, after 5 years HRCT changes p = 0.163, FEV1 p = 0.551, FVC p = 0.362, DLco p = 0.620 and 10 years of follow-up HRCT changes p = 0.853, FEV1 p = 0.589, FVC p = 0.328, DLco p = 0.992). However, patients with the ID genotype showed a significant reduction in FEV1 after 10 years of follow-up in comparison to baseline levels (91.0 (IR 80.0-105.0) at the time of diagnosis and 84.0 (IR 69.0-99.0) after 10 years, p = 0.014). Our study suggests that ACE 1 gene polymorphisms do not have a role in the severity of SSc-ILD. Further studies are needed to explain the exact role of ACE 1 gene polymorphisms in SSc-ILD and SSc in general.

Radiation-Induced Lung Injury With Lung Cancer Treated With the Combination Therapy of Nintedanib and Dexamethasone

Radiation-induced lung injury (RILI) associated with lung cancer becomes refractory. Nintedanib is a multi-kinase inhibitor that suppresses the development of pulmonary fibrosis. Herein, we report a case of RILI with progressive pulmonary fibrosis after stereotactic body radiation therapy in a 70-year-old man with lung cancer. The patient responded well to the initial prednisolone therapy but became resistant during tapering. The combination therapy of nintedanib and dexamethasone resulted in a temporary improvement in RILI. Nintedanib is not a standard therapy for RILI, and further investigation is needed to evaluate the effects of nintedanib on RILI complicated by lung cancer.

Structural and functional characteristics of the pulmonary hemomicrocirculatory bed in induced systemic sclerosis: an experimental study

The objective of this study was to investigate the effects of prolonged exposure to the oxidative agent NaClO on histopathological changes in the lung tissues of laboratory animals. Specifically, the study aimed to examine morphological changes in the pulmonary microcirculation and the level of vascular cell adhesion molecule-1 (VCAM-1) as a functional activity indicator of endothelial cells in animals with induced systemic sclerosis (SSc). A laboratory animal model was used to assess the impact of long-term exposure to NaClO on lung tissues. The animals were divided into three groups: the experimental group (25 rats) was exposed to NaClO, while the control group (20 rats) received an isotonic solution, and the intact group (15 animals) was without any exposure. The concentration of VCAM-1 in the serum of the animals was measured using an enzyme-linked immunosorbent assay. Histopathological analysis of lung tissue specimens was performed using both light and electron microscopy. The concentration of VCAM-1 in the serum of the animals in the experimental group was significantly higher than that of the control group (91.25 [85.63-143.75] vs 19.50 [13.53-22.20], p < 0.05). The histopathological analysis revealed significant abnormalities in the lung tissue specimens from the experimental group, including disruption in the structure of the hemocapillaries of the lungs, narrowing of the microvessel lumen, and perivascular infiltration by polymorphonuclear cells. The electron microscopic analysis showed several ultrastructural changes in the endotheliocytes of the hemocapillaries, including uneven expansion of the perinuclear space, swollen mitochondria, and fragmentation of the membranes of the granular endoplasmic reticulum. Additionally, the basement membrane of hemocapillaries showed uneven thickening with indistinct contours, and the peripheral parts of endotheliocytes were marked by numerous micropinocytotic vesicles and vacuoles. Erythrocyte aggregates and leukocyte adhesion were identified in the lumen of many hemocapillaries, while adhesion and aggregation of platelets were also observed in several hemocapillaries. Long-term exposure to NaClO can cause significant histopathological changes in lung tissues, including damage to the hemocapillaries and disruption in the structure of endotheliocytes.

Spontaneous Pneumo-Mediastinum in a Post-COVID-19 Patient with Systemic Sclerosis

Pulmonary involvement is the most common cause of death among patients with systemic sclerosis (SSc). The current coronavirus disease 2019 (COVID-19) is particularly problematic to manage in SSc patients since they may experience a more severe evolution of COVID-19 due to the pre-existent interstitial lung disease (ILD) and the administration of immunosuppressive treatments. In addition, the remarkable radiological similarities between SSc-ILD and COVID-19 complicate the differential diagnosis between these two entities. Herein, we present the first case of spontaneous pneumo-mediastinum in a post-COVID-19 patient with SSc. In our patient, both smoking and pulmonary fibrosis could lead to cyst formation, which possibly spontaneously broke and caused pneumo-mediastinum. Moreover, megaesophagus perforation due to the smooth muscle atrophy, replacement with fibrosis, and achalasia may extend into the mediastinum or pleural space and has also been described as a rare case of spontaneous pneumo-pericardium. Finally, spontaneous pneumo-mediastinum and pneumothorax have been recently reported as an established complication of severe COVID-19 pneumonia and among COVID-19 long-term complication. This case report underlines that the worsening of respiratory symptoms in SSc patients, especially when recovered from COVID-19, requires further investigations for ruling out other tentative diagnoses besides the evolution of the SSc-ILD.

Tocilizumab therapy in juvenile systemic sclerosis: a retrospective single centre pilot study

To evaluate the efficacy and safety of anti-interleukin (IL)-6 receptor antibody tocilizumab (TCZ) as a treatment option of juvenile systemic sclerosis (JSS). Nine JSS patients were assigned to a TCZ, additionally to conventional treatment (steroids, methotrexate, mycophenolate-mofetil). The modified Rodnan skin score (mRSS), carbon-monoxide diffusion capacity (DLCO), thorax high-resolution tomography (HRCT), patient global assessment (PGA) and Juvenile Systemic Sclerosis Severity (J4S) score were used to explore the efficacy of treatment. Nine JSS patients were treated with TCZ with a median treatment duration of 10 (1-21) months. Nine patients (77.8%) had radiologically confirmed improvement on thorax HRCT, 7 (77.8%) had decreased PGA (mean pre-treatment PGA 3.7 vs. 2.3 post-treatment PGA 2), 6 (66.7%) had increased DLCO (mean pre-treatment DLCO 69.14% vs. post-treatment DLCO 79.50%) after the TCZ treatment. In all patients mRSS and the J4S decreased: 26.1 vs. 19.7 and 8.2 vs. 4.7, respectively. Changes in mRSS, DLCO, PGA and J4S were statistically significant: p = 0.012, 0.04, 0.026 and 0.007, respectively. All patients tolerated well TCZ treatment. JSS is a rare condition characterized with skin fibrosis and internal organ involvement. Tocilizumab represents a potential treatment option for patients unresponsive to conventional treatment. Long-term prospective studies with higher number of patients are needed to provide more relevant data.