Characterization of the PF-ILD phenotype in patients with advanced pulmonary sarcoidosis

Drug Design in the Age of Network Medicine and Systems Biology: Transcriptomics Identifies Potential Drug Targets Shared by Sarcoidosis and Pulmonary Hypertension

Network medicine considers the interconnectedness of human diseases and their underlying molecular substrates. In this context, sarcoidosis and pulmonary hypertension (PH) have long been thought of as distinct diseases, but there is growing evidence of shared molecular mechanisms. This study reports on common differentially expressed genes (DEGs), regulatory elements, and pathways between the two diseases. Publicly available transcriptomic datasets for sarcoidosis (GSE157671) and PH (GSE236251) were retrieved from the Gene Expression Omnibus database. DEGs were identified using GEO2R, followed by pathway enrichment and gene interaction analyses via GeneMANIA and STRING. Importantly, a total of 13 common DEGs were identified between sarcoidosis and PH, with 7 upregulated and 6 downregulated genes. The SMAD2/3 nuclear pathway was a shared enriched pathway, suggesting a role in fibrosis and immune regulation. There were also divergences between sarcoidosis and PH. For example, gene set enrichment analysis indicated significant associations of the IFN-gamma signaling pathway with sarcoidosis and the TNF-alpha signaling with PH. miRNA network analysis identified hsa-miR-34a-5p, hsa-let-7g-5p, and hsa-miR-19a-3p as key shared regulators linked to common genes in both sarcoidosis and PH. Finally, DGIdb analysis revealed potential therapeutic candidates targeting these genes in both diseases. This study contributes to the field of drug design and discovery from a network medicine standpoint. The shared molecular links uncovered between sarcoidosis and PH in this study point to several potential biomarkers and therapeutic targets. Further experimental validation and translational medical research are called for diagnostics and drugs, which can effectively and safely help the clinical management of both diseases.

Fibrotic Pulmonary Sarcoidosis-From Pathogenesis to Management

Sarcoidosis is a multiorgan, granulomatous disease of an unknown etiology. The characteristic feature of the disease is the formation of noncaseating granulomas. Spontaneous resolution occurs in most patients, but the clinical course may be chronic or progressive, complicated by pulmonary fibrosis, which is a major cause of mortality in sarcoidosis. Recent studies have provided new information on the immunological mechanisms of pulmonary fibrosis. Its pathogenesis includes the alteration of lymphocyte activity and the imbalance between their subpopulations, the polarization of macrophages to the profibrotic phenotype, and an imbalance between the activity of metalloproteinases and their tissue inhibitors. A multidisciplinary approach is required for the optimal management of fibrotic pulmonary sarcoidosis. Clinical symptoms, serum biomarkers, imaging, pulmonary function test results, other organ involvement, comorbidities, and complications should be considered when assessing disease activity and selecting the most appropriate treatment. The use of anti-inflammatory drugs is often discussed. There has been no consensus reached on whether antifibrotic agents should be added or used in monotherapy as initial treatment in such cases. This article will review all the information on fibrotic pulmonary sarcoidosis and present factors associated with fibrosis development, prognosis, and treatment options.

Advanced pulmonary sarcoidosis

Sarcoidosis affects the lungs in most patients. Manifestations of pulmonary sarcoidosis range from asymptomatic to death. Approximately a quarter of sarcoidosis patients develop chronic pulmonary disease. Advanced pulmonary sarcoidosis patients are those who have progressive disease and are at risk for significant morbidity and mortality. There are several features associated with advanced pulmonary disease: pulmonary fibrosis, pulmonary hypertension, chronic pulmonary inflammation, and/or complications of disease or therapy. Large retrospective studies have identified pulmonary fibrosis and pulmonary hypertension as the major causes of respiratory failure and death in pulmonary sarcoidosis. The high-resolution computer tomography scan (HRCT) and echocardiogram are key methods in screening for pulmonary hypertension and pulmonary fibrosis. Therapy for chronic pulmonary inflammation has been the major focus in chronic disease. However, treatment for pulmonary hypertension has been studied in sarcoidosis. To date, treatment studies for sarcoidosis associated progressive pulmonary fibrosis have been underpowered to demonstrate clear cut benefit of anti-fibrotic agents.

Alveolar nitric oxide concentration as a potential biomarker of fibrosis and active disease in pulmonary sarcoidosis: a pilot study

Sarcoidosis is considered a T-helper (Th) 1 related disease, but a transition from Th1 to Th2 pathway activation has been postulated in sarcoidosis-associated pulmonary fibrosis (SAPF). Fraction of exhaled nitric oxide (FENO) is a marker of Th2 airway inflammation, but alveolar concentration of nitric oxide (CANO) can be measured to assess Th2 inflammation in the periphery of the lung. The aim of this study is to assess whether CANO can be considered a biomarker of SAPF or active pulmonary sarcoidosis. In this single-center retrospective study, we compared exhaled NO levels of patients with pulmonary sarcoidosis without fibrosis (N= 11) with those obtained from patients with SAPF (N= 15). Clinical data, as well as respiratory function tests, were also analyzed. FENO (28.5 ± 16 ppb vs 30.9 ± 17.2 ppb,p= 0.72) and CANO (4.4 ± 3.5 ppb vs 3.2 ± 1.7 ppb,p= 0.73) levels did not differ significantly between patients with or without SAPF, even when dividing them according to treatment or disease activity. CANO appeared reduced in patients with active sarcoidosis (2.1 ± 0.8 ppb vs 4.1 ± 3 ppb,p< 0.05). In conclusion, CANO cannot be considered a biomarker of SAPF. Its lower level in patients with active disease confirms the prevalence of Th1 inflammation in granuloma formation and suggests its potential role as a biomarker of active pulmonary sarcoidosis, but further studies with larger samples are needed to confirm this hypothesis.

Family history of pulmonary fibrosis impacts prognosis in patients with sarcoidosis

Having a family member with pulmonary fibrosis (PF) impacts the prognosis of sarcoidosis patients, as the majority of patients reporting at least one relative with PF present fibrotic characteristics and one-third develop a progressive phenotype https://bit.ly/40KC7Cr.

Association between the HAL score and the development of progressive pulmonary fibrosis in idiopathic interstitial pneumonia: A prospective observational study

BACKGROUND

Progressive pulmonary fibrosis (PPF) is a critical concern in interstitial lung disease (ILD) management. The HAL score, which incorporates honeycombing (H), age >75 years (A), and serum lactate dehydrogenase >222 U/L (L), can predict acute exacerbations in patients with idiopathic interstitial pneumonia (IIP). This study aims to evaluate the predictive utility of the HAL score for PPF development.

METHODS

This study was a post-hoc analysis of a multicenter prospective cohort study involving patients with IIP. PPF was diagnosed if at least two of the following three criteria were met: worsening respiratory symptoms, radiological progression, and physiological progression.

RESULTS

Among the 144 patients, 29 (22.3%) developed PPF during the observation period. Among the three criteria for PPF, a higher HAL score significantly correlated with worsening respiratory symptoms (p = 0.001) and radiological progression (p = 0.022), but not with physiological progression (p = 0.717). Therefore, a higher HAL score significantly correlated with an increased PPF risk (12.5% for a score of 0, 25.9% for a score of 1, and 33.3% for a score of ≥2; p = 0.032). The HAL score also correlated with overall survival (p < 0.001). For the 92 patients (70.8%) with non-idiopathic pulmonary fibrosis (IPF), the HAL score was significantly associated with PPF development (p = 0.021), while not for the 38 patients (29.2%) with IPF (p = 0.872).

CONCLUSION

In patients with non-IPF, the HAL score correlated with PPF development and could be useful to monitor those patients and to avoid missed treatment opportunities.

Sarcoidosis versus Granulomatous and Lymphocytic Interstitial Lung Disease in Common Variable Immunodeficiency: A Comparative Review

Sarcoidosis and Granulomatous and Lymphocytic Interstitial Lung Diseases (GLILD) are two rare entities primarily characterised by the development of Interstitial Lung Disease (ILD) in the context of systemic immune dysregulation. These two conditions partially share the immunological background and pathologic findings, with granuloma as the main common feature. In this narrative review, we performed a careful comparison between sarcoidosis and GLILD, with an overview of their main similarities and differences, starting from a clinical perspective and ending with a deeper look at the immunopathogenesis and possible target therapies. Sarcoidosis occurs in immunocompetent individuals, whereas GLILD occurs in patients affected by common variable immunodeficiency (CVID). Moreover, peculiar extrapulmonary manifestations and radiological and histological features may help distinguish the two diseases. Despite that, common pathogenetic pathways have been suggested and both these disorders can cause progressive impairment of lung function and variable systemic granulomatous and non-granulomatous complications, leading to significant morbidity, reduced quality of life, and survival. Due to the rarity of these conditions and the extreme clinical variability, there are still many open questions concerning their pathogenesis, natural history, and optimal management. However, if studied in parallel, these two entities might benefit from each other, leading to a better understanding of their pathogenesis and to more tailored treatment approaches.

Sarcoidosis-Associated Pulmonary Hypertension

Sarcoidosis-associated pulmonary hypertension (SAPH) is a very severe complication of the disease, largely impacting its morbidity and being one of its strongest predictors of mortality. With the recent modifications of the hemodynamic definition of pulmonary hypertension (mean arterial pulmonary pressure >20 instead of <25 mmHg,) its prevalence is presently not precisely known, but it affects from 3 to 20% of sarcoid patients; mostly, although not exclusively, those with an advanced, fibrotic pulmonary disease. Its gold-standard diagnostic tool remains right heart catheterization (RHC). The decision to perform it relies on an expert decision after a non-invasive work-up, in which echocardiography remains the screening tool of choice. The mechanisms underlying SAPH, very often entangled, are crucial to define, as appropriate and personalized therapeutic strategies will aim at targeting the most significant ones. There are no recommendations so far as to the indications and modalities of the medical treatment of SAPH, which is based upon the opinion of a multidisciplinary team of sarcoidosis, pulmonary hypertension and sometimes lung transplant experts.

High-Resolution CT Scan Fibrotic Patterns in Stage IV Pulmonary Sarcoidosis: Impact on Pulmonary Function and Survival

BACKGROUND

Different patterns of fibrosis on high-resolution CT scans (HRCT) have been associated with reduced survival in some interstitial lung diseases. Nothing is known about HRCT scan patterns and survival in sarcoidosis.

RESEARCH QUESTION

Will a detailed description of the extent and pattern of HRCT scan fibrosis in patients with stage IV pulmonary sarcoidosis impact pulmonary function and survival?

STUDY DESIGN AND METHODS

Two hundred forty patients with stage IV sarcoidosis at two large tertiary institutions were studied. The earliest HRCT scan with fibrosis was reviewed for extent of fibrosis (< 10%, 10%-20%, and > 20%) and presence of bronchiectasis, upper lobe fibrocystic changes, basal subpleural honeycombing, ground-glass opacities (GGOs), large bullae, and mycetomas. Presence of sarcoidosis-associated pulmonary hypertension (SAPH) and pulmonary function testing performed within 1 year of HRCT were recorded. Patients were followed up until last clinic visit, death, or lung transplantation.

RESULTS

The mean age was 58.4 years. Seventy-four percent were Black, 63% were female, and mean follow-up was 7.4 years. Death or LT occurred in 53 patients (22%). Thirty-one percent had > 20% fibrosis, 25% had 10%-20% fibrosis, and 44% had < 10% fibrosis. The most common HRCT abnormalities were bronchiectasis (76%), upper lobe fibrocystic changes (36%), and GGOs (28%). Twelve percent had basal subpleural honeycombing, and 32% had SAPH. Patients with > 20% fibrosis had more severe pulmonary impairment, were more likely to have SAPH (53%), and had worse survival (44% mortality; P < .001). Upper lobe fibrocystic changes, basal subpleural honeycombing, and large bullae were associated with worse pulmonary function and worse survival. Patients with basal subpleural honeycombing had the worst pulmonary function and survival (55% mortality; P < .001). GGOs were associated with worse pulmonary function but not worse survival, and mycetomas were associated with worse survival but not worse pulmonary function. A Cox proportional hazards model indicated that basal subpleural honeycombing (hazard ratio, 7.95), diffusion capacity for carbon monoxide < 40% (HR, 5.67) and White race (hazard ratio, 2.61) were independent predictors of reduced survival.

INTERPRETATION

HRCT scan features of fibrotic pulmonary sarcoidosis had an impact on pulmonary function and survival. Presence of >20% fibrosis and basal subpleural honeycombing are predictive of worse pulmonary function and worse survival in patients with stage IV pulmonary sarcoidosis.

Fibrotic Pulmonary Sarcoidosis

Fibrotic pulmonary sarcoidosis (fPS) affects about 20% of patients. fPS carries a significant morbidity and mortality. However, its prognosis is highly variable, depending mainly on fibrosis extent, functional impairment severity, and the development of pulmonary hypertension. Moreover, fPS outcomes are also influenced by several other complications, including acute exacerbations, and infections. fPS natural history is unknown, in particular regarding the risk of progressive self-sustaining fibrosis. The management of fPS is challenging, including anti-inflammatory treatment if granulomatous activity persists, rehabilitation, and in highly selected patients antifibrotic treatment and lung transplantation.

High-Risk Sarcoidosis: A Focus on Pulmonary, Cardiac, Hepatic and Renal Advanced Diseases, as Well as on Calcium Metabolism Abnormalities

Although sarcoidosis is generally regarded as a benign condition, approximately 20-30% of patients will develop a chronic and progressive disease. Advanced pulmonary fibrotic sarcoidosis and cardiac involvement are the main contributors to sarcoidosis morbidity and mortality, with failure of the liver and/or kidneys representing additional life-threatening situations. In this review, we discuss diagnosis and treatment of each of these complications and highlight how the integration of clinical, pathological and radiological features may help predict the development of such high-risk situations in sarcoid patients.

Establishing a Diagnosis of Pulmonary Sarcoidosis

Pulmonary sarcoidosis is the most prevalent manifestation of sarcoidosis and the commonest diagnosis in clinics for ILD. Due to the lack of a simple and reliable test, making the diagnosis is often challenging. There are three criteria that must always be considered: (1) compatible clinical presentation; (2) evidence of granuloma formation (usually non-caseating); and (3) exclusion of alternative causes of granulomatous disease. There are various tools available for diagnosis, amongst which serum biomarkers like sACE and sIL-2R, HRCT, BAL, EBUS/EUS and sometimes bronchoscopic or surgical lung biopsy are most contributive. However, the degree of invasiveness of the applied test and associated risk to the patient must be weighed against management consequences. In specific situations (e.g., presentation as Löfgren's syndrome) or when there is high suspicion based on HRCT in the context of supportive clinical findings, it might be justifiable to decide on a "working diagnosis of sarcoidosis" and to refrain from further invasive procedures for the patient. This should, however, preferably be agreed upon after discussion in an experienced multidisciplinary team and requires close follow-up of the patient. In general, it is advisable to always maintain a healthy dose of skepticism when making the diagnosis of sarcoidosis, especially when the clinical course of disease gives rise to this.

Cluster features in fibrosing interstitial lung disease and associations with prognosis

BACKGROUND

Clustering is helpful in identifying subtypes in complex fibrosing interstitial lung disease (F-ILD) and associating them with prognosis at an early stage of the disease to improve treatment management. We aimed to identify associations between clinical characteristics and outcomes in patients with F-ILD.

METHODS

Retrospectively, 575 out of 926 patients with F-ILD were eligible for analysis. Four clusters were identified based on baseline data using cluster analysis. The clinical characteristics and outcomes were compared among the groups.

RESULTS

Cluster 1 was characterized by a high prevalence of comorbidities and hypoxemia at rest, with the worst lung function at baseline; Cluster 2 by young female patients with less or no smoking history; Cluster 3 by male patients with highest smoking history, the most noticeable signs of velcro crackles and clubbing of fingers, and the severe lung involvement on chest image; Cluster 4 by male patients with a high percentage of occupational or environmental exposure. Clusters 1 (median overall survival [OS] = 7.0 years) and 3 (OS = 5.9 years) had shorter OS than Clusters 2 (OS = not reached, Cluster 1: p < 0.001, Cluster 3: p < 0.001) and 4 (OS = not reached, Cluster 1: p = 0.004, Cluster 3: p < 0.001). Clusters 1 and 3 had a higher cumulative incidence of acute exacerbation than Clusters 2 (Cluster 1: p < 0.001, Cluster 3: p = 0.014) and 4 (Cluster 1: p < 0.001, Cluster 3: p = 0.006). Stratification by using clusters also independently predicted acute exacerbation (p < 0.001) and overall survival (p < 0.001).

CONCLUSIONS

The high degree of disease heterogeneity of F-ILD can be underscored by four clusters based on clinical characteristics, which may be helpful in predicting the risk of fibrosis progression, acute exacerbation and overall survival.

Phenotypes of Sarcoidosis-Associated Pulmonary Hypertension-A Challenging Mystery

Sarcoidosis has been a well-recognised risk factor for pulmonary hypertension (PH) for a long time, but still, the knowledge about this concatenation is incomplete. Sarcoidosis-associated PH (SAPH) is an uncommon but serious complication associated with increased morbidity and mortality among sarcoidosis patients. The real epidemiology of SAPH remains unknown, and its pathomechanisms are not fully explained. Sarcoidosis is a heterogeneous and dynamic condition, and SAPH pathogenesis is believed to be multifactorial. The main roles in SAPH development play: parenchymal lung disease with the destruction of pulmonary vessels, the extrinsic compression of pulmonary vessels by conglomerate masses, lymphadenopathy or fibrosing mediastinitis, pulmonary vasculopathy, LV dysfunction, and portal hypertension. Recently, it has been recommended to individually tailor SAPH management according to the predominant pathomechanism, i.e., SAPH phenotype. Unfortunately, SAPH phenotyping is not a straightforward process. First, there are gaps in our understanding of undergoing processes. Second, the assessment of such a pivotal element as pulmonary vasculature on a microscopic level is non-feasible in SAPH patients antemortem. Finally, SAPH is a dynamic condition, multiple phenotypes usually coexist, and patients can switch between phenotypes during the course of sarcoidosis. In this article, we summarise the basic knowledge of SAPH, describe SAPH phenotypes, and highlight some practical problems related to SAPH phenotyping.

Sarcoidosis-associated pulmonary fibrosis: joining the dots

Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology. A minority of patients with sarcoidosis develop sarcoidosis-associated pulmonary fibrosis (SAPF), which may become progressive. Genetic profiles differ between patients with progressive and self-limiting disease. The mechanisms of fibrosis in SAPF are not fully understood, but SAPF is likely a distinct clinicopathological entity, rather than a continuum of acute inflammatory sarcoidosis. Risk factors for the development of SAPF have been identified; however, at present, it is not possible to make a robust prediction of risk for an individual patient. The bulk of fibrotic abnormalities in SAPF are located in the upper and middle zones of the lungs. A greater extent of SAPF on imaging is associated with a worse prognosis. Patients with SAPF are typically treated with corticosteroids, second-line agents such as methotrexate or azathioprine, or third-line agents such as tumour necrosis factor inhibitors. The antifibrotic drug nintedanib is an approved treatment for slowing the decline in lung function in patients with progressive fibrosing interstitial lung diseases, but more evidence is needed to assess its efficacy in SAPF. The management of patients with SAPF should include the identification and treatment of complications such as bronchiectasis and pulmonary hypertension. Further research is needed into the mechanisms underlying SAPF and biomarkers that predict its clinical course.

Molecular Mechanism in the Development of Pulmonary Fibrosis in Patients with Sarcoidosis

Sarcoidosis is a multisystemic disease of unknown etiology characterized by the formation of granulomas in various organs, especially lung and mediastinal hilar lymph nodes. The clinical course and manifestations are unpredictable: spontaneous remission can occur in approximately two thirds of patients; up to 20% of patients have chronic course of the lung disease (called advanced pulmonary sarcoidosis, APS) resulting in progressive loss of lung function, sometimes life-threatening that can lead to respiratory failure and death. The immunopathology mechanism leading from granuloma formation to the fibrosis in APS still remains elusive. Recent studies have provided new insights into the genetic factors and immune components involved in the clinical manifestation of the disease. In this review we aim to summarize the clinical-prognostic characteristics and molecular pathways which are believed to be associated with the development of APS.

Lymphocyte Subsets and Pulmonary Nodules to Predict the Progression of Sarcoidosis

The search for biological markers, which allow a relatively accurate assessment of the individual course of pulmonary sarcoidosis at the time of diagnosis, remains one of the research priorities in this field of pulmonary medicine. The aim of our study was to investigate possible prognostic factors for pulmonary sarcoidosis with a special focus on cellular immune inflammation markers. A 2-year follow-up of the study population after the initial prospective and simultaneous analysis of lymphocyte activation markers expression in the blood, as well as bronchoalveolar lavage fluid (BALF) and lung biopsy tissue of patients with newly diagnosed pulmonary sarcoidosis, was performed. We found that some blood and BAL fluid immunological markers and lung computed tomography (CT) patterns have been associated with a different course of sarcoidosis. We revealed five markers that had a significant negative association with the course of sarcoidosis (worsening pulmonary function tests and/or the chest CT changes)-blood CD4+CD31+ and CD4+CD44+ T lymphocytes, BALF CD8+CD31+ and CD8+CD103+ T lymphocytes and a number of lung nodules on chest CT at the time of the diagnosis. Cut-off values, sensitivity, specificity and odds ratio for predictors of sarcoidosis progression were calculated. These markers may be reasonable predictors of sarcoidosis progression.

Genetics in Idiopathic Pulmonary Fibrosis: A Clinical Perspective

BACKGROUND

Unraveling the genetic background in a significant proportion of patients with both sporadic and familial IPF provided new insights into the pathogenic pathways of pulmonary fibrosis.

AIM

The aim of the present study is to overview the clinical significance of genetics in IPF.

PERSPECTIVE

It is fascinating to realize the so-far underestimated but dynamically increasing impact that genetics has on aspects related to the pathophysiology, accurate and early diagnosis, and treatment and prevention of this devastating disease. Genetics in IPF have contributed as no other in unchaining the disease from the dogma of a "a sporadic entity of the elderly, limited to the lungs" and allowed all scientists, but mostly clinicians, all over the world to consider its many aspects and "faces" in all age groups, including its co-existence with several extra pulmonary conditions from cutaneous albinism to bone-marrow and liver failure.

CONCLUSION

By providing additional evidence for unsuspected characteristics such as immunodeficiency, impaired mucus, and surfactant and telomere maintenance that very often co-exist through the interaction of common and rare genetic variants in the same patient, genetics have created a generous and pluralistic yet unifying platform that could lead to the understanding of the injurious and pro-fibrotic effects of many seemingly unrelated extrinsic and intrinsic offending factors. The same platform constantly instructs us about our limitations as well as about the heritability, the knowledge and the wisdom that is still missing.