Combined Pulmonary Fibrosis and Emphysema Syndrome: A New Phenotype within the Spectrum of Smoking-Related Interstitial Lung Disease

Combined Pulmonary Fibrosis and Emphysema: When Scylla and Charybdis Ally

Combined pulmonary fibrosis and emphysema (CPFE) is a recently recognized syndrome that, as its name indicates, involves the existence of both interstitial lung fibrosis and emphysema in one individual, and is often accompanied by pulmonary hypertension. This debilitating, progressive condition is most often encountered in males with an extensive smoking history, and is presented by dyspnea, preserved lung volumes, and contrastingly impaired gas exchange capacity. The diagnosis of the disease is based on computed tomography imaging, demonstrating the coexistence of emphysema and interstitial fibrosis in the lungs, which might be of various types and extents, in different areas of the lung and several relative positions to each other. CPFE bears high mortality and to date, specific and efficient treatment options do not exist. In this review, we will summarize current knowledge about the clinical attributes and manifestations of CPFE. Moreover, we will focus on pathophysiological and pathohistological lung phenomena and suspected etiological factors of this disease. Finally, since there is a paucity of preclinical research performed for this particular lung pathology, we will review existing animal studies and provide suggestions for the development of additional in vivo models of CPFE syndrome.

Smoking-related interstitial lung disease

Exposure to smoke is associated with the development of diseases of the airways and lung parenchyma. Apart from chronic obstructive pulmonary disease (COPD), in some individuals, tobacco smoke can also trigger mechanisms of interstitial damage that result in various pathological changes and pulmonary fibrosis. A causal relation has been established between tobacco smoke and a group of entities that includes respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), desquamative interstitial pneumonia (DIP), Langerhans cell histiocytosis (LCH), and acute eosinophilic pneumonia (AEP). Smoking is considered a risk factor for idiopathic pulmonary fibrosis (IPF); however, the role and impact of smoking in the development of this differentiated clinical entity, which has also been called combined pulmonary fibrosis and emphysema (CPFE) as well as nonspecific interstitial pneumonia (NIP), remains to be determined. The definition of smoking-related interstitial fibrosis (SRIF) is relatively recent, with differentiated histological characteristics. The likely interconnection between the mechanisms involved in inflammation and pulmonary fibrosis in all these processes often results in an overlapping of clinical, radiological, and histological features in the same patient that can sometimes lead to radiological patterns of interstitial lung disease that are impossible to classify. For this reason, a combined approach to diagnosis is recommendable. This combined approach should be based on the joint interpretation of the histological and radiological findings while taking the clinical context into consideration. This paper aims to describe the high-resolution computed tomography (HRCT) findings in this group of disease entities in correlation with the clinical manifestations and histological changes underlying the radiological pattern.

Raucherassoziierte interstitielle Lungenerkrankungen

Klinisches Problem

Raucherassoziierte interstitielle Lungenerkrankungen umfassen heterogene pulmonale Pathologien, deren korrekte Diagnostik prognostische und therapeutische Konsequenzen hat. In diesem Artikel werden die gängigsten raucherassoziierten interstitiellen Lungenerkrankungen beschrieben sowie eine strukturierte Herangehensweise präsentiert, welche den diagnostischen Arbeitsprozess erleichtern kann.

Empfehlungen für die Praxis

Die Computertomographie (CT) besitzt einen hohen Stellenwert in der Diagnose der raucherassoziierten interstitiellen Lungenerkrankungen und kann dazu beitragen, Lungenbiopsien zu verhindern. Um eine hohe diagnostische Genauigkeit zu erreichen, sollten standardisierte Untersuchungsprotokolle sowie eine strukturierte Herangehensweise in der Befundung zur Anwendung kommen. In den entzündlich dominierten Stadien der respiratorischen Bronchiolitis (RB), der respiratorischen Bronchiolitis mit interstitieller Lungenerkrankung (RB-ILD) sowie der desquamativen interstitiellen Pneumonie (DIP) haben die Beendigung des Rauchens sowie Steroide den größten therapeutischen Effekt. Bei fibrotischen Veränderungen (z. B. im Rahmen einer idiopathischen pulmonalen Fibrose [IPF]) können antifibrotische Therapien mit Pirfenidon und Nintedanib zum Einsatz kommen. Patienten mit dem Verdacht auf raucherassoziierte interstitielle Lungenerkrankung sollten in multidisziplinären Boards abgeklärt und behandelt werden.

Differential Genomic Profile in TERT, DSP, and FAM13A Between COPD Patients With Emphysema, IPF, and CPFE Syndrome

Background: Genetic association studies have identified single nucleotide polymorphisms (SNPs) associated with lasting lung diseases such as Chronic Obstructive Pulmonary Disease (COPD) and Idiopathic Pulmonary Fibrosis (IPF), as well as the simultaneous presentation, known as Combined Pulmonary Fibrosis and Emphysema (CPFE) Syndrome. It is unknown if these diseases share genetic variants previously described in an independent way. This study aims to identify common or differential variants between COPD, IPF, and CPFE. Materials and methods: The association analysis was carried out through a case-control design in a Mexican mestizo population (n = 828); three patients' groups were included: COPD smokers (COPD-S, n = 178), IPF patients (n = 93), and CPFE patients (n = 16). Also, two comparison groups were analyzed: smokers without COPD (SWOC, n = 367) and healthy subjects belonging to the Mexican Pulmonary Aging Cohort (PAC, n = 174). Five SNPs in four genes previously associated to interstitial and obstructive diseases were selected: rs2609255 (FAM13A), rs2736100 (TERT), rs2076295 (DSP) rs5743890, and rs111521887 (TOLLIP). Genotyping was performed by qPCR using predesigned Taqman probes. Results: In comparing IPF vs. PAC, significant differences were found in the frequency of the rs260955 G allele associated with the IPF risk (OR = 1.68, p = 0.01). Also, the genotypes, GG of rs260955 (OR = 2.86, p = 0.01) and TT of rs2076295 (OR = 1.79, p = 0.03) were associated with an increased risk of IPF; after adjusting by covariables, only the rs260955 G allele remain significant (p = 0.01). For the CPFE vs. PAC comparison, an increased CPFE risk was identified since there is a difference in the rs2736100 C allele (OR = 4.02, p < 0.01; adjusted p < 0.01). For COPD-S, the rs2609255 TG genotype was associated with increased COPD risk after adjusting by covariables. Conclusion: The rs2736100 C allele is associated with decreased IPF risk and confers an increased risk for CPFE. Also, the rs2076295 TT genotype is associated with increased IPF risk, while the GG genotype is associated with CFPE susceptibility. The rs2609255 G allele and GG genotype are associated with IPF susceptibility, while the TG genotype is present in patients with emphysema.

Combined Pulmonary Fibrosis and Emphysema (CPFE) Clinical Features and Management

Background

Combined pulmonary fibrosis and emphysema (CPFE) is an underrecognized syndrome characterized by chronic, progressive disease with a dismal prognosis. Frequent co-morbidities with a higher incidence than in idiopathic pulmonary fibrosis or emphysema alone are pulmonary hypertension (WHO group 3) in 47–90% of the patients and lung cancer in 46.8% of the patients.

Objective

Review current evidence and knowledge concerning diagnosis, risk factors, disease evolution and treatment options of CPFE.

Methods

We searched studies reporting CPFE in original papers, observational studies, case reports, and meta-analyses published between 1990 and August 2020, in the PubMed, Embase, Cochrane Library, Wiley Online Library databases and Google Scholar using the search terms [CPFE], [pulmonary fibrosis] OR [IPF] AND [emphysema]. Bibliographies of retrieved articles were searched as well. Further inclusion criteria were publications in English, French, German and Italian, with reference to humans. In vitro data and animal data were not considered unless they were mentioned in studies reporting predominantly human data.

Results

Between May 1, 1990, and September 1, 2020, we found 16 studies on CPFE from the online sources and bibliographies. A total of 890 patients are described in the literature. Although male/female ratio was not reported in all studies, the large majority of patients were male (at least 78%), most of them were current or former heavy smokers.

Conclusion

CPFE is a syndrome presenting with dyspnea on exertion followed by disruptive cough and recurrent exacerbations. The disease may progress rapidly, be aggravated by pulmonary hypertension WHO group 3 and is associated with an increased risk of lung cancer. Smoking and male sex are important risk factors. There is a need for more research on CPFE especially relating to etiology, influence of genetics, treatment and prevention options. Antifibrotic therapy might be an interesting treatment option for these patients.

Differential expression of caveolin-1 during pathogenesis of combined pulmonary fibrosis and emphysema: Effect of phosphodiesterase-5 inhibitor

INTRODUCTION

Combined pulmonary fibrosis and emphysema (CPFE) is a relatively new entity within the spectrum of cigarette smoke induced lung disorders. Currently there is no consensus about its treatment. We hypothesized that caveolin-1 critically determines the parenchymal and vascular remodeling leading to the development of CPFE. We assessed the effect of therapeutic targeting of caveolin-1 in mesenchymal and endothelial cells by the phosphodiesterase-5 inhibitor, sildenafil.

METHODS

Male Wistar rats (n = 168) were exposed to; room air (control); bleomycin (7 U/kg), bleomycin+sildenafil (50 mg/kg/day P.O.), cigarette smoke (CS) (4 Gold Flake 69 mm/day), CS + sildenafil, CS + bleomycin, CS + bleomycin+sildenafil. Animals were euthanized at 8, 9, 11, 12 weeks and lung histopathological changes, collagen deposition, ROS, Xanthine oxidase, caveolin-1 determined.

RESULTS

Cigarette smoke causes progressive ROS accumulation, caveolin-1 up-regulation in alveolar epithelial cells, alveolar macrophages, peribronchiolar fibroblasts, endothelial and vascular smooth muscle cells, interstitial inflammation and emphysema. Sildenafil reduces oxidative stress, parenchymal caveolin-1 and attenuates emphysema caused by CS. Bleomycin increases lung ROS and downregulates caveolin-1 leading to fibroblast proliferation and fibrosis. Combined cigarette smoke and bleomycin exposure, results in differential caveolin-1 expression and heterogeneous parenchymal remodeling with alternating areas of emphysema and fibrosis. Increased caveolin-1 induces premature senescence of lung fibroblasts and emphysema. Decreased caveolin-1 is associated with propagation of EMT and fibrosis. Sildenafil attenuates the parenchymal remodeling however it is not effective in reducing VSMC hypertrophy in combined group.

CONCLUSION

CPFE is characterized by heterogenous parenchymal remodeling and differential caveolin-1 expression. Sildenafil therapy attenuates parenchymal pathologies in CPFE. Additional therapy is however needed for attenuating VSMC remodeling.

Combined pulmonary fibrosis and emphysema characteristics in a Greek cohort

Background

Combined pulmonary fibrosis and emphysema (CPFE) has recently received great attention, with studies suggesting that it presents a distinct clinical entity while others have challenged this hypothesis. This nationwide study aimed to describe a large cohort of Greek CPFE patients and to examine potential prognostic factors for survival.

Methods

This retrospective study included 97 patients with CPFE. Demographic and clinical data, pulmonary function tests, echocardiography results and bronchoalveolar lavage analysis were recorded.

Results

Most patients were male (94.8%) and 92% were current or ex-smokers. Spirometry results were abnormal (forced vital capacity (FVC) 72.9±19.9% pred and forced expiratory volume in 1 s/FVC 82.9±9.7%) with reduced diffusing capacity of the lung for carbon monoxide (D_LCO) (42.3±17.4% pred). Mean systolic pulmonary arterial pressure was 41.9±19.7 mmHg and pulmonary hypertension was present in 58.8% of patients. Mean 6-min walk distance was 335.4±159.4 m. Mean emphysema score was 14.23±8.69% and mean interstitial lung disease (ILD) extent was 39.58±19.82%. Mean survival was 84 months (95% CI 72–96 months). Patients with D_LCO ≥39% pred had better survival than patients with D_LCO <39% pred (p=0.031). Patients with ILD extent ≥30% had worse survival than patients with ILD extent <30% (p=0.037).

Conclusions

Our results indicate that CPFE patients have preserved lung volumes associated with disproportionately reduced D_LCO, while reduced D_LCO and increased ILD extent was associated with worse prognosis.

Prognosis of CPFE is associated with pulmonary function status and ILD extenthttp://ow.ly/izvd30nHFgh

Improvement of pulmonary arterial compliance by pulmonary vasodilator in pulmonary hypertension from combined pulmonary fibrosis and emphysema

Combined pulmonary fibrosis and emphysema (CPFE) is a common but under-recognized syndrome characterized with distinct profiles of both pulmonary fibrosis and emphysema. Pulmonary hypertension (PH) is particularly prone to develop as a common complication, leading to exercise limitation and worse prognosis of CPFE. Although the therapy of patients with PH from CPFE cannot be endorsed, an individual treatment may be considerable when accompanying severe PH. We report a case of a 71-year-old male with PH from CPFE, who improved pulmonary arterial compliance (PAC) and exercise capacity in response to pulmonary vasodilator.

[The respiratory effects of smoking]

A marked increase in the morbidity and mortality of a large number of broncho-pulmonary diseases has been documented in relation to smoking. The influence of tobacco smoking on various respiratory conditions. is discussed: incidence, severity or natural history modification of some respiratory illnesses: obstructive lung diseases (COPD, asthma), lung cancer, bacterial, viral respiratory infections, with the impact of smoking on tuberculosis. Finally, the relationship of tobacco with diffuse interstitial lung disease: protective role of smoking (controversial in sarcoidosis, real in hypersensitivity pneumonitis). The benefits of smoking cessation are described.

Current Concepts in Pathogenesis, Diagnosis, and Management of Smoking-Related Interstitial Lung Diseases

Tobacco exposure results in various changes to the airways and lung parenchyma. Although emphysema represents the more common injury pattern, in some individuals, cigarette smoke injures alveolar epithelial cells and other lung cells, resulting in diffuse infiltrates and parenchymal fibrosis. Smoking can trigger interstitial injury patterns mediated via recruitment and inappropriate persistence of myeloid and other immune cells, including eosinophils. As our understanding of the role of cigarette smoke constituents in triggering lung injury continues to evolve, so does our recognition of the spectrum of smoking-related interstitial lung changes. Although respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia, pulmonary Langerhans cell histiocytosis, and acute eosinophilic pneumonia have a well-established association with tobacco use, its role and impact on idiopathic pulmonary fibrosis, combined pulmonary fibrosis and emphysema, and connective tissue disease-related interstitial lung diseases is still ambiguous. Smoking-related interstitial fibrosis is a relatively newly appreciated entity with distinct histopathologic features but with unclear clinical ramifications. Increased implementation of lung cancer screening programs and utilization of CT scans in thoracic imaging have also resulted in increased identification of "incidental" or "subclinical" interstitial lung changes in smokers, the ensuing impact of which remains to be studied.

Clinical characteristics and outcomes of lung cancer patients with combined pulmonary fibrosis and emphysema: a systematic review and meta-analysis of 13 studies

Background

The characteristic and outcomes of lung cancer patients with combined pulmonary fibrosis and emphysema (CPFE) have long been assessed, but results were controversial. Therefore, we performed a meta-analysis to assess the clinical features and prognosis of lung cancer patients with CPFE.

Methods

The databases PubMed, Embase, and Web of Science (updated to October 1, 2017) were searched for eligible studies. Pooled odds ratios (ORs), weighted mean differences (WMD) or hazard ratios (HRs) with 95% confidence intervals (95% CIs) were used to evaluate the clinicopathological characteristics, the short-term outcome after operation and long-term survival of lung cancer patients with CPFE compared with lung cancer patients without CPFE (fibrosis, emphysema, and normal).

Results

Thirty original studies with 8,050 patients were included in this meta-analysis. The pooled results indicated that lung cancer patients with CPFE were associated with higher age (MD =3.39; 95% CI: 2.12-4.67, P<0.001), male (OR =8.46; 95% CI: 6.36-11.26, P<0.001), ex- or current smoker (OR =39.65; 95% CI: 15.64-100.5, P<0.001), longer smoking history (MD =15.56; 95% CI: 3.73-27.39, P=0.01), lower DLCO% (MD =-13.82; 95% CI: -21.4 to -6.24, P<0.001), squamous cell carcinoma histology (OR =3.55; 95% CI: 2.49-5.05, P<0.001), the lower lobes (OR =1.92; 95% CI: 1.52-2.43, P<0.001), advanced pathological stage (OR =1.55; 95% CI: 1.22-1.96, P<0.001). Lung cancer patients with CPFE had higher 30-day mortality (OR =4.72, 95% CI: 2.06-10.85, P<0.001), 90-day mortality (OR =5.33; 95% CI: 1.39-20.42, P=0.01), and incidence of postoperative complications (OR =5.25, 95% CI: 2.38-11.57, P<0.001). In addition, the lung cancer patients with CPFE had a poorer OS (HR =2.006, 95% CI: 1.347-2.986, P=0.001) than lung cancer patients without CPFE.

Conclusions

This meta-analysis demonstrated that lung cancer patients with CPFE have more aggressive clinical characteristic and a poor prognosis, suggesting that lung cancer patients with CPFE should be early detected, treated reasonably and be taken good care of.

Comparative study of two models of combined pulmonary fibrosis and emphysema in mice

Combined pulmonary fibrosis and emphysema (CPFE) is an "umbrella term" encompassing emphysema and pulmonary fibrosis, but its pathogenesis is not known. We established two models of CPFE in mice using tracheal instillation with bleomycin (BLM) or murine gammaherpesvirus 68 (MHV-68). Experimental mice were divided randomly into four groups: A (normal control, n=6), B (emphysema, n=6), C (emphysema+MHV-68, n=24), D (emphysema+BLM, n=6). Group C was subdivided into four groups: C1 (sacrificed on day 367, 7 days after tracheal instillation of MHV-68); C2 (day 374; 14days); C3 (day 381; 21days); C4 (day 388; 28days). Conspicuous emphysema and interstitial fibrosis were observed in BLM and MHV-68 CPFE mouse models. However, BLM induced diffuse pulmonary interstitial fibrosis with severely diffuse pulmonary inflammation; MHV-68 induced relatively modest inflammation and fibrosis, and the inflammation and fibrosis were not diffuse, but instead around bronchioles. Inflammation and fibrosis were detectable in the day-7 subgroup and reached a peak in the day-28 subgroup in the emphysema + MHV-68 group. Levels of macrophage chemoattractant protein-1, macrophage inflammatory protein-1α, interleukin-13, and transforming growth factor-β1 in bronchoalveolar lavage fluid were increased significantly in both models. Percentage of apoptotic type-2 lung epithelial cells was significantly higher; however, all four types of cytokine and number of macrophages were significantly lower in the emphysema+MHV-68 group compared with the emphysema +BLM group. The different changes in pathology between BLM and MHV-68 mice models demonstrated different pathology subtypes of CPFE: macrophage infiltration and apoptosis of type-II lung epithelial cells increased with increasing pathology score for pulmonary fibrosis.

Lung Cancer in Combined Pulmonary Fibrosis and Emphysema: A Systematic Review and Meta-Analysis

Purpose

Patients with combined pulmonary fibrosis and emphysema (CPFE) have been suggested to have an increased risk of lung cancer. We conducted a systematic review of all published data and performed a meta-analysis to define the characteristics of lung cancer that develops in CPFE.

Method

We searched Pubmed, Embase, and Cochrane to find original articles about lung cancer and CPFE published prior to September 2015. All titles/abstracts were reviewed by two radiologists to identify articles that used predefined selection criteria. Summary estimates were generated using a random-effect model and odds ratios (ORs) to develop squamous cell carcinoma (SqCC) were calculated. Kaplan–Meier survival curves were obtained for the survival of patients with CPFE and non-CPFE.

Results

Nine original articles that assessed 620 patients were included in this review. In the pooled data, patients were older age (70.4 years), almost all were heavy smokers (53.5 pack years), and males were predominant (92.6%). SqCC was the most common type (42.3%), followed by adenocarcinoma (34.4%). Compared with lung cancer population with an otherwise normal lung, the OR to develop SqCC in CPFE was 9.06 (95% CI, 6.08–13.5). The ORs in CPFE compared with lung cancers that developed in lungs with fibrosis or emphysema were also higher. The median survival for CPFE patients with lung cancer (19.5 months) was significantly shorter than in non-CPFE (53.1 months).

Conclusions

Lung cancer in CPFE, most commonly SqCC, presents in elderly heavy smokers with a male predominance. The median survival for CPFE patients with lung cancer is 19.5 months.

Combined pulmonary fibrosis and emphysema (CPFE): what radiologist should know

Combined pulmonary fibrosis and emphysema is a relatively newly defined entity, which has been deeply studied in the recent years. Despite the wide numbers of papers on this topic, there are still several open questions about pathogenesis, epidemiology, natural history and prognosis. The diagnosis could be assessed only after HRCT scan as functional tests often result in an underestimation of this syndrome. What radiologists need to know about this syndrome consists in the heterogeneity of appearances: emphysema is mainly paraseptal and fibrotic pattern could be variable, including the variant of airspace enlargement with fibrosis which needs to be differentiated from honeycombing. A special attention must be paid on complications which could worsen the prognosis, such as pulmonary hypertension and lung cancer. Further studies are needed to address if the type of fibrotic pattern as well as fibrosis CT index could be considered as prognostic factors. Thus, the role of radiologists in the management of these patients is crucial as it involves diagnosis, detection of complications and could possible concerns the identification of patients at higher risk.

Electron Microscopic Analysis of Silicate and Calcium Particles in Cigarette Smoke Tar

Scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS) supplies information that is complementary to those data traditionally obtained using inductively coupled plasma-mass spectrometry for analysis of inorganic tobacco and tobacco smoke constituents. The SEM-EDS approach was used to identify select inorganic constituents of mainstream cigarette smoke "tar." The nature of SEM-EDS instrumentation makes it an ideal choice for microstructural analyses as it provides information relevant to inorganic constituents that could result from exposure to combusted tobacco products. Our analyses show that aluminum silicates, silica, and calcium compounds were common constituents of cigarette mainstream smoke "tar." Identifying inorganic tobacco smoke constituents is important because inhalation of fine inorganic particles could lead to inflammatory responses in the lung and systemic inflammatory responses. As cigarette smoking causes chronic inflammation in the respiratory tract, information on inorganic particulate in mainstream smoke informs efforts to determine causative agents associated with increased morbidity and mortality from tobacco use.

The evolving role of MDCT in the assessment of patients with chronic obstructive pulmonary disease

The purpose of this article is to educate the reader in the value a radiologist can offer in the multidetector (MD) CT assessment of patients with chronic obstructive pulmonary disease (COPD). MDCT can identify patients in whom treatments such as lung volume reduction surgery or newer endobronchial therapies may be of benefit. We will also discuss important and under-recognised associated cardiorespiratory disease, which may be incidentally identified.

Smoking-related idiopathic interstitial pneumonia

Cigarette smoking is a key factor in the development of numerous pulmonary diseases. An international group of clinicians, radiologists and pathologists evaluated patients with previously identified idiopathic interstitial pneumonia (IIP) to determine unique features of cigarette smoking. Phase 1 (derivation group) identified smoking-related features in patients with a history of smoking (n=41). Phase 2 (validation group) determined if these features correctly predicted the smoking status of IIP patients (n=100) to participants blinded to smoking history. Finally, the investigators sought to determine if a new smoking-related interstitial lung disease phenotype could be defined. Phase 1 suggested that preserved forced vital capacity with disproportionately reduced diffusing capacity of the lung for carbon monoxide, and various radiographic and histopathological findings were smoking-related features. In phase 2, the kappa coefficient among clinicians was 0.16 (95% CI 0.11-0.21), among the pathologists 0.36 (95% CI 0.32-0.40) and among the radiologists 0.43 (95% CI 0.35-0.52) for smoking-related features. Eight of the 100 cases were felt to represent a potential smoking-related interstitial lung disease. Smoking-related features of interstitial lung disease were identified in a minority of smokers and were not specific for smoking. This study is limited by its retrospective design, the potential for recall bias in smoking history and lack of information on second-hand smoke exposure. Further research is needed to understand the relationship between smoking and interstitial lung disease.