Determinants of progression in idiopathic pulmonary fibrosis

Genetic association between smoking and DLCO in idiopathic pulmonary fibrosis patients

BACKGROUND

Observational studies have shown that smoking is related to the diffusing capacity of the lungs for carbon monoxide (DLCO) in individuals with idiopathic pulmonary fibrosis (IPF). Nevertheless, further investigation is needed to determine the causal effect between these two variables. Therefore, we conducted a study to investigate the causal relationship between smoking and DLCO in IPF patients using two-sample Mendelian randomization (MR) analysis.

METHODS

Large-scale genome-wide association study (GWAS) datasets from individuals of European descent were analysed. These datasets included published lifetime smoking index (LSI) data for 462,690 participants and DLCO data for 975 IPF patients. The inverse-variance weighting (IVW) method was the main method used in our analysis. Sensitivity analyses were performed by MR‒Egger regression, Cochran's Q test, the leave-one-out test and the MR-PRESSO global test.

RESULTS

A genetically predicted increase in LSI was associated with a decrease in DLCO in IPF patients [ORIVW = 0.54; 95% CI 0.32-0.93; P = 0.02].

CONCLUSIONS

Our study suggested that smoking is associated with a decrease in DLCO. Patients diagnosed with IPF should adopt an active and healthy lifestyle, especially by quitting smoking, which may be effective at slowing the progression of IPF.

Inhaled pulmonary surfactant biomimetic liposomes for reversing idiopathic pulmonary fibrosis through synergistic therapeutic strategy

Idiopathic pulmonary fibrosis (IPF) stands as a highly heterogeneous and deadly lung disease, yet the available treatment options remain limited. Combining myofibroblast inhibition with ROS modulation in damaged AECs offers a comprehensive strategy to halt IPF progression, but delivering drugs separately to these cell types is challenging. Inspired by the successful application of pulmonary surfactant (PS) replacement therapy in lung disease treatment, we have developed PS nano-biomimetic liposomes (PSBs) to utilize its natural transport pathway for targeting AECs while reducing lung tissue clearance. In this collaborative pulmonary drug delivery system, PSBs composed of DPPC/POPG/DPPG/CHO (20:9:5:4) were formulated for inhalation. These PSBs loaded with ROS-scavenger astaxanthin (AST) and anti-fibrosis drug pirfenidone (PFD) were aerosolized for precise quantification and mimicking patient inhalation. Through aerosol inhalation, the lipid membrane of PSBs gradually fused with natural PS, enabling AST delivery to AECs by hitchhiking with PS circulation. Simultaneously, PFD was released within the PS barrier, effectively penetrating lung tissue to exert therapeutic effects. In vivo results have shown that PSBs offer numerous therapeutic advantages in mice with IPF, particularly in terms of lung function recovery. This approach addresses the challenges of drug delivery to specific lung cells and offers potential benefits for IPF patients.

Baseline plasma KL-6 level predicts adverse outcomes in patients with idiopathic pulmonary fibrosis receiving nintedanib: a retrospective real-world cohort study

Background

Nintedanib is effective for treating idiopathic pulmonary fibrosis (IPF), but some patients may exhibit a suboptimal response and develop on-treatment acute exacerbation (AE-IPF), hepatic injury, or mortality. It remains unclear which patients are at risk for these adverse outcomes.

Methods

We analysed the demographic and clinical data, baseline plasma levels of Krebs von den Lungen-6 (KL-6) and surfactant protein A (SPA), and longitudinal clinical courses of a real-world cohort of IPF patients who received nintedanib ≥ 14 days between March 2017 and December 2020. Cox proportional-hazards regression, subdistribution hazards regression, and sensitivity analyses were performed to investigate the association between baseline predictors and AE-IPF, mortality, and nintedanib-related hepatic injury. The relationship between baseline predictors and pulmonary function decline was determined.

Results

Fifty-seven patients were included, of whom 24 (42%) developed hepatic injury, 20 (35%) had AE-IPF, and 16 (28%) died on-treatment. A baseline plasma KL-6 level ≥ 2.5 ng/mL, and diffusion capacity for carbon monoxide (D_LCO) < 55% predicted, were associated with increased risk of hepatic injury (adjusted hazard ratio [aHR] was 3.46; 95% CI 1.13–10.60; p = 0.029 for KL-6, and 6.05; 95% CI 1.89–19.32; p = 0.002 for D_LCO). Both factors also predicted severe and recurrent hepatic injury. Patients with baseline KL-6 ≥ 2.5 ng/mL also had a higher risk of AE-IPF (aHR 4.52; 95% CI 1.63–12.55; p = 0.004). For on-treatment mortality, baseline KL-6 ≥ 3.5 ng/mL and SPA ≥ 600 pg/mL were significant predictors (aHR 5.39; 95% CI 1.16–24.97; p = 0.031 for KL-6, and aHR 12.28; 95% CI 2.06–73.05; p = 0.006 for SPA). Results from subdistribution hazard regression and sensitivity analyses supported these findings. Patients with elevated baseline plasma KL-6 levels also exhibited a trend towards faster pulmonary function decline.

Conclusions

For patients with IPF who are receiving nintedanib, we have identified baseline predictors, in particular plasma KL-6 levels, for the risk of adverse outcomes. Patients with these predictors may require close monitoring for unfavourable responses during treatment. Our findings also support the prognostic role of molecular markers like KL-6 and may contribute to future formulation of more individualized therapeutic strategies for IPF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01530-6.

Using hyperpolarized 129Xe gas-exchange MRI to model the regional airspace, membrane, and capillary contributions to diffusing capacity

Hyperpolarized ¹²⁹Xe MRI has emerged as a novel means to evaluate pulmonary function via 3D mapping of ventilation, interstitial barrier uptake, and RBC transfer. However, the physiological interpretation of these measurements has yet to be firmly established. Here, we propose a model that uses the three components of ¹²⁹Xe gas-exchange MRI to estimate accessible alveolar volume (V_A), membrane conductance, and capillary blood volume contributions to DL_CO. ¹²⁹Xe ventilated volume (VV) was related to V_A by a scaling factor k_V = 1.47 with 95% confidence interval [1.42, 1.52], relative ¹²⁹Xe barrier uptake (normalized by the healthy reference value) was used to estimate the membrane-specific conductance coefficient k_B = 10.6 [8.6, 13.6] mL/min/mmHg/L, whereas normalized RBC transfer was used to calculate the capillary blood volume-specific conductance coefficient k_R = 13.6 [11.4, 16.7] mL/min/mmHg/L. In this way, the barrier and RBC transfer per unit volume determined the transfer coefficient K_CO, which was then multiplied by image-estimated V_A to obtain DL_CO. The model was built on a cohort of 41 healthy subjects and 101 patients with pulmonary disorders. The resulting ¹²⁹Xe-derived DL_CO correlated strongly (R² = 0.75, P < 0.001) with the measured values, a finding that was preserved within each individual disease cohort. The ability to use ¹²⁹Xe MRI measures of ventilation, barrier uptake, and RBC transfer to estimate each of the underlying constituents of DL_CO clarifies the interpretation of these images while enabling their use to monitor these aspects of gas exchange independently and regionally.NEW & NOTEWORTHY The diffusing capacity for carbon monoxide (DL_CO) is perhaps one of the most comprehensive physiological measures used in pulmonary medicine. Here, we spatially resolve and estimate its key components-accessible alveolar volume, membrane, and capillary blood volume conductances-using hyperpolarized ¹²⁹Xe MRI of ventilation, interstitial barrier uptake, and red blood cell transfer. This image-derived DL_CO correlates strongly with measured values in 142 subjects with a broad range of pulmonary disorders.

Predictors of mortality in interstitial lung disease patients without pulmonary hypertension

BACKGROUND:

There is a paucity of information regarding prognostic factors associated with reduced survival in interstitial lung disease (ILD) patients without pulmonary hypertension (PH).

AIMS:

The aim of this study was to determine physiological and hemodynamic parameters that impact survival among ILD patients without PH based on right heart catheterization (RHC).

METHODS:

Consecutive ILD patients who underwent RHC (n = 169) at one center were included. The information analyzed included demographics and physiological and hemodynamic parameters. Cox regression models were used to identify independent predictors of survival.

RESULTS:

The mean age was 55.0 years, and 49.7% of the patients were females. Thirty-three patients died, and two underwent transplantation. Patients with predicted diffusion capacity of the lung for carbon monoxide <35%, walking distance <300 m, and 6-min walk test (6MWT) final oxygen saturation measured by pulse oximetry (SpO ₂) <85% were significantly associated with an increased mortality risk (P = 0.022, P < 0.0001, and P = 0.049, respectively; all by log-rank analysis). Advanced age, idiopathic pulmonary fibrosis diagnosis, reduced forced vital capacity, and low cardiac index were independent predictors of increased mortality in the ILD cohort.

CONCLUSIONS:

Our study demonstrates that parameters obtained from baseline pulmonary function tests and 6MWTs are important determinants of survival in ILD patients without PH. Importantly, cardiac index was the only hemodynamic variable independently associated with survival. Thus, in the absence of PH, when ILD patients perform poorly during the 6MWT manifested as reduced walking distance and desaturation at the end of the test, cardiovascular impairment must be ruled out.

Pulmonary function testing in children's interstitial lung disease

The use of pulmonary function tests (PFTs) has been widely described in airway diseases like asthma and cystic fibrosis, but for children's interstitial lung disease (chILD), which encompasses a broad spectrum of pathologies, the usefulness of PFTs is still undetermined, despite widespread use in adult interstitial lung disease. A literature review was initiated by the COST/Enter chILD working group aiming to describe published studies, to identify gaps in knowledge and to propose future research goals in regard to spirometry, whole-body plethysmography, infant and pre-school PFTs, measurement of diffusing capacity, multiple breath washout and cardiopulmonary exercise tests in chILD. The search revealed a limited number of papers published in the past three decades, of which the majority were descriptive and did not report pulmonary function as the main outcome.PFTs may be useful in different stages of management of children with suspected or confirmed chILD, but the chILD spectrum is diverse and includes a heterogeneous patient group in all ages. Research studies in well-defined patient cohorts are needed to establish which PFT and outcomes are most relevant for diagnosis, evaluation of disease severity and course, and monitoring individual conditions both for improvement in clinical care and as end-points in future randomised controlled trials.

Monocyte-derived multipotent cell delivered programmed therapeutics to reverse idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a highly heterogeneous and fatal disease. However, IPF treatment has been limited by the low drug delivery efficiency to lungs and dysfunctional "injured" type II alveolar epithelial cell (AEC II). Here, we present surface-engineered nanoparticles (PER NPs) loading astaxanthin (AST) and trametinib (TRA) adhered to monocyte-derived multipotent cell (MOMC) forming programmed therapeutics (MOMC/PER). Specifically, the cell surface is designed to backpack plenty of PER NPs that reach directly to the lungs due to the homing characteristic of the MOMC and released PER NPs retarget injured AEC II after responding to the matrix metalloproteinase-2 (MMP-2) in IPF tissues. Then, released AST can enhance synergetic effect of TRA for inhibiting myofibroblast activation, and MOMC can also repair injured AEC II to promote damaged lung regeneration. Our findings provide proof of concept for developing a strategy for cell-mediated lung-targeted delivery platform carrying dual combined therapies to reverse IPF.

A predictive factor for patients with acute respiratory distress syndrome: CT lung volumetry of the well-aerated region as an automated method

PURPOSE

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury that frequently shows fatal outcomes. As radiographic predictive factors, some reports have focused on the region of ill-aerated lung, but none have focused on well-aerated lung. Our objective was to evaluate the relationship between computed tomography (CT) volume of the well-aerated lung region and prognosis in patients with ARDS.

METHOD

This retrospective observational study of a single intensive care unit (ICU) included patients with ARDS treated between April 2011 and May 2013. We identified 42 patients with ARDS for whom adequate helical CT scans were available. CT images were analyzed for 3-dimensional reconstruction, and lung region volumes were measured using automated volumetry methods. Lung regions were identified by CT attenuation in Hounsfield units (HU).

RESULTS

Of the 42 patients, 35 (83.3 %) survived 28 days and 32 (76.2 %) survived to ICU discharge. CT lung volumetry was performed within 144.5 ± 76.6 s, and inter-rater reliability of CT lung volumetry for lung regions below -500 HU (well-aerated lung region) were near-perfect. Well-aerated lung region showed a positive correlation with 28-day survival (P = 0.020), and lung volumes below -900 HU correlated positively with 28-day survival and ICU survival, respectively (P = 0.028, 0.017). Survival outcome was better for percentage of well-aerated lung region/predicted total lung capacity ≥40 % than for <40 % (P = 0.039).

CONCLUSIONS

CT lung volumetry of the well-aerated lung region using an automated method allows fast, reliable quantitative CT analysis and potentially prediction of the clinical course in patients with ARDS.

Loss of Vascular CD34 Results in Increased Sensitivity to Lung Injury

Survival during lung injury requires a coordinated program of damage limitation and rapid repair. CD34 is a cell surface sialomucin expressed by epithelial, vascular, and stromal cells that promotes cell adhesion, coordinates inflammatory cell recruitment, and drives angiogenesis. To test whether CD34 also orchestrates pulmonary damage and repair, we induced acute lung injury in wild-type (WT) and Cd34^-/- mice by bleomycin administration. We found that Cd34^-/- mice displayed severe weight loss and early mortality compared with WT controls. Despite equivalent early airway inflammation to WT mice, CD34-deficient animals developed interstitial edema and endothelial delamination, suggesting impaired endothelial function. Chimeric Cd34^-/- mice reconstituted with WT hematopoietic cells exhibited early mortality compared with WT mice reconstituted with Cd34^-/- cells, supporting an endothelial defect. CD34-deficient mice were also more sensitive to lung damage caused by influenza infection, showing greater weight loss and more extensive pulmonary remodeling. Together, our data suggest that CD34 plays an essential role in maintaining vascular integrity in the lung in response to chemical- and infection-induced tissue damage.

The Evaluation of Interstitial Abnormalities in Group B of the 2011 Global Initiative for Chronic Obstructive Lung Disease (GOLD) Classification of Chronic Obstructive Pulmonary Disease (COPD)

Objective In 2011, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification categorized chronic obstructive pulmonary disease (COPD) patients into 4 groups. A report demonstrated that the mortality in Group B was higher than that in Group C. Ischemic heart disease and cancer were suggested to be the cause. The aim of the present study was to test the hypothesis that interstitial lung abnormalities (ILAs) are more prevalent in Group B than Group C and that they may be responsible for the higher mortality in Group B. Methods Patients were selected based on their pulmonary function test results. The inclusion criterion was a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of <70% after the inhalation of a bronchodilator. Patients without a smoking history or computed tomography (CT) scan were excluded. The medical records of the patients were retrospectively reviewed, and the selected patients were categorized into Groups A to D. High-resolution CT scans were used to investigate the presence of ILAs and determine the low attenuation area (LAA). Results Among the 349 COPD patients, ILAs were detected in 10.3% of the patients in Group A, 22.5% of the patients in Group B, 5.6% of the patients in Group C, and 23.1% of the patients in Group D. In Group B, the frequency of ILAs was significantly higher and the area affected by the ILAs was significantly greater in comparison to Group C. Among the patterns of interstitial abnormalities, the area of honeycombing in Group B was significantly greater than that in Group C. Furthermore, among the patients in Group B, the LAA in the ILA-positive patients was significantly greater than that in the ILA-negative patients. Conclusion In Group B, the area occupied by ILAs-especially honeycombing-was greater than that in Group C. This contributed to the preserved %FEV1 and possibly to the poorer prognosis of the patients in Group B.

The biology of the ABCA3 lipid transporter in lung health and disease

The lipid transporter, ATP-binding cassette class A3 (ABCA3), is a highly conserved multi-membrane-spanning protein that plays a critical role in the regulation of pulmonary surfactant homeostasis. Mutations in ABCA3 have been increasingly recognized as one of the causes of inherited pulmonary diseases. These monogenic disorders produce familial lung abnormalities with pathological presentations ranging from neonatal surfactant-deficiency-induced respiratory failure to childhood or adult diffuse parenchymal lung diseases for which specific treatment modalities remain limited. More than 200 ABCA3 mutations have been reported to date with approximately three quarters of patients presenting as compound heterozygotes. Recent advances in our understanding of the molecular basis underlying normal ABCA3 biosynthesis and processing and of the mechanisms of alveolar epithelial cell dysregulation caused by the expression of its mutant forms are beginning to emerge. These insights and the role of environmental factors and modifier genes are discussed in the context of the considerable variability in disease presentation observed in patients with identical ABCA3 gene mutations. Moreover, the opportunities afforded by an enhanced understanding of ABCA3 biology for targeted therapeutic strategies are addressed.

Lost after translation: insights from pulmonary surfactant for understanding the role of alveolar epithelial dysfunction and cellular quality control in fibrotic lung disease

Dating back nearly 35 years ago to the Witschi hypothesis, epithelial cell dysfunction and abnormal wound healing have reemerged as central concepts in the pathophysiology of idiopathic pulmonary fibrosis (IPF) in adults and in interstitial lung disease in children. Alveolar type 2 (AT2) cells represent a metabolically active compartment in the distal air spaces responsible for pulmonary surfactant biosynthesis and function as a progenitor population required for maintenance of alveolar integrity. Rare mutations in surfactant system components have provided new clues to understanding broader questions regarding the role of AT2 cell dysfunction in the pathophysiology of fibrotic lung diseases. Drawing on data generated from a variety of model systems expressing disease-related surfactant component mutations [surfactant proteins A and C (SP-A and SP-C); the lipid transporter ABCA3], this review will examine the concept of epithelial dysfunction in fibrotic lung disease, provide an update on AT2 cell and surfactant biology, summarize cellular responses to mutant surfactant components [including endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and intrinsic apoptosis], and examine quality control pathways (unfolded protein response, the ubiquitin-proteasome system, macroautophagy) that can be utilized to restore AT2 homeostasis. This integrated response and its derangement will be placed in the context of cell stress and quality control signatures found in patients with familial or sporadic IPF as well as non-surfactant-related AT2 cell dysfunction syndromes associated with a fibrotic lung phenotype. Finally, the need for targeted therapeutic strategies for pulmonary fibrosis that address epithelial ER stress, its downstream signaling, and cell quality control are discussed.

Validation of the GAP score in Korean patients with idiopathic pulmonary fibrosis

BACKGROUND

No study has determined whether the risk of mortality predicted by the GAP (gender, age, and physiologic variables) model matches the observed mortality from idiopathic pulmonary fibrosis (IPF) in non-Western populations. We evaluated the clinical course of IPF and validated the GAP model in Korean patients with IPF.

METHODS

We included 268 patients who received a diagnosis of IPF at Seoul National University Hospital between 2005 and 2009. For each patient, demographics and clinical data, such as lung physiologic parameters at IPF diagnosis, were evaluated. We validated the GAP model using discrimination and calibration to predict the risk of death in Korean patients with IPF.

RESULTS

The study population comprised 181 men and 87 women (mean age, 65.9 years). The mean baseline % predicted FVC was 77, and % predicted diffusing capacity of lung for carbon monoxide was 65.9. A total of 157 deaths (58.6%) occurred during follow-up, and the median time to death was 4.64 years. The observed cumulative mortality at 1, 2, and 3 years was 10.4%, 20.9%, and 31.0%, respectively. The GAP model produced estimates of 1-year mortality risk consistent with the observed data (C statistic: GAP calculator, 0.74; GAP index and staging system, 0.72; P < .29). However, calibration of the GAP model at 3 years was not satisfactory.

CONCLUSIONS

The GAP model showed similar discrimination power compared with the original cohort but did not predict the 3-year risk of death accurately. Further multinational validation studies are needed.

Urokinase-type plasminogen activator receptor (uPAR) ligation induces a raft-localized integrin signaling switch that mediates the hypermotile phenotype of fibrotic fibroblasts

The urokinase-type plasminogen activator receptor (uPAR) is a glycosylphosphatidylinositol-linked membrane protein with no cytosolic domain that localizes to lipid raft microdomains. Our laboratory and others have documented that lung fibroblasts from patients with idiopathic pulmonary fibrosis (IPF) exhibit a hypermotile phenotype. This study was undertaken to elucidate the molecular mechanism whereby uPAR ligation with its cognate ligand, urokinase, induces a motile phenotype in human lung fibroblasts. We found that uPAR ligation with the urokinase receptor binding domain (amino-terminal fragment) leads to enhanced migration of fibroblasts on fibronectin in a protease-independent, lipid raft-dependent manner. Ligation of uPAR with the amino-terminal fragment recruited α5β1 integrin and the acylated form of the Src family kinase, Fyn, to lipid rafts. The biological consequences of this translocation were an increase in fibroblast motility and a switch of the integrin-initiated signal pathway for migration away from the lipid raft-independent focal adhesion kinase pathway and toward a lipid raft-dependent caveolin-Fyn-Shc pathway. Furthermore, an integrin homologous peptide as well as an antibody that competes with β1 for uPAR binding have the ability to block this effect. In addition, its relative insensitivity to cholesterol depletion suggests that the interactions of α5β1 integrin and uPAR drive the translocation of α5β1 integrin-acylated Fyn signaling complexes into lipid rafts upon uPAR ligation through protein-protein interactions. This signal switch is a novel pathway leading to the hypermotile phenotype of IPF patient-derived fibroblasts, seen with uPAR ligation. This uPAR dependent, fibrotic matrix-selective, and profibrotic fibroblast phenotype may be amenable to targeted therapeutics designed to ameliorate IPF.

The role of lung biopsy in the diagnosis and management of idiopathic interstitial pneumonia

Idiopathic interstitial pneumonias (IIP) are a relatively common cause of diffuse lung disease marked by varying degrees of inflammation and fibrosis within the lung, leading to substantial morbidity and mortality. Knowledge and progress in therapeutics have been hindered by inconsistent definitions and challenges in diagnosis. Present classification schemes are based on morphologic definitions that frequently require synthesis of clinical, radiologic and histopathologic information. This review focuses on the present state of diagnosis, and the role that history, radiographic imaging and surgical lung biopsy have on the diagnosis of IIPs. Surgical lung biopsy plays a key role in distinguishing specific IIPs in patients whose imaging studies lack features diagnostic of usual interstitial pneumonia. The final diagnosis is based on the combined clinical, radiographic and histologic findings, and is best accomplished using a dynamic, multidisciplinary approach. More accurate diagnoses should increase the ability to study and understand the biology, natural history and potential therapies for this group of devastating diseases.

Role of Proteases in Inflammatory Lung Diseases

Proteases are enzymes that have the capacity to hydrolyze peptide bonds and degrade other proteins. Proteases can promote inflammation by regulating expression and activity of different pro-inflammatory cytokines, chemokines and other immune components in the lung compartment. They are categorized in three major subcategories: serine proteases, metalloproteases and cysteine proteases especially in case of lung diseases. Neutrophil-derived serine proteases (NSPs), metalloproteases and some mast cell-derived proteases are mainly focused here. Their modes of actions are different in different diseases for e.g. NE induces the release of IL-8 from lung epithelial cells through a MyD88/IRAK/TRAF-6-dependent pathway and also through EGFR MAPK pathway. NSPs contribute to immune regulation during inflammation through the cleavage and activation of specific cellular receptors. MMPs can also influence the progression of various inflammatory processes and there are many non-matrix substrates for MMPs, such as chemokines, growth factors and receptors. During lung inflammation interplay between NE and MMP is an important significant phenomenon. They have been evaluated as therapeutic targets in several inflammatory lung diseases. Here we review the role of proteases in various lung inflammatory diseases with emphasis on their mode of action and contribution to immune regulation during inflammation.

The genetic and environmental causes of pulmonary fibrosis

Although substantial progress has been made in understanding the clinical, radiological, and pathological manifestations of fibrosing interstitial lung diseases (ILD), it remains difficult for the clinician to predict the clinical course or the response to therapy for the subtypes of ILD, even from individual to individual with the same diagnosis. This article reviews the genetic and environmental causes of pulmonary fibrosis, specifically focusing on genetic and epigenetic variants of MUC5B and several types of ILD, to discuss why only some individuals with the MUC5B promoter polymorphism develop pulmonary fibrosis. Once we discover how these genetic and epigenetic risks lead to the development of ILD, we and others can apply these discoveries to: (1) identify individuals at risk of developing ILD, (2) diagnose the condition at an earlier stage, (3) identify novel mechanisms that cause ILD, and (4) eventually develop personalized therapeutic strategies for intervention.

Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic condition of unknown etiology with an unfavorable outcome from progressively deteriorating respiratory function, leading ultimately to death from respiratory failure. It is characterized by sequential acute lung injury resulting in progressive fixed tissue fibrosis, architectural distortion and loss of function. An excess of profibrotic cytokines and/or a deficiency in antifibrotic cytokines have been implicated in the pathological process as has excessive oxidation. IPF is distinguished from other forms of diffuse pulmonary fibrosis by the presence of the specific histological pattern of usual interstitial pneumonitis. Oral corticosteroids are the usual treatment, but objective response rates are poor and good quality studies do not exist. Other therapies either alone or in combination with corticosteroids are widely used, including azathioprine, colchicine, cyclophosphamide and penicillamine. There is a paucity of good quality information regarding the effectiveness of most noncorticosteroid immunosuppressive agents. Older studies of lesser methodological quality have shown benefits from these drugs, generally when added to corticosteroids. Many were retrospective reviews or uncontrolled, nonrandomized, open-label, prospective studies and often included other histological patterns of disease which are now thought to respond better to immunosuppressive agents. The results of intervention with colchicine and azathioprine have been disappointing when assessed by good quality trials using modern diagnostic criteria. Modern high quality studies are lacking for several agents, notably cyclophosphamide and penicillamine. The older agents may yet prove to be effective but further good quality trials will be necessary to assess these agents adequately. Other new anti-inflammatory, antioxidant, antifibrotic or anticytokine compounds are largely untried or unreported. One trial using interferon-gamma-1b showed a significant improvement in pulmonary function but there are concerns regarding the generalizability of this study. Pirfenidone, cyclosporine and acetylcysteine may also prove to be of benefit but current studies are of insufficient quality to allow for any conclusions to be drawn. Currently there is no good evidence to support the routine use of oral corticosteroids, azathioprine, cyclophosphamide, penicillamine, colchicine, cyclosporine or any other immunosuppressive, antifibrotic or immunomodulatory agent in the management of IPF. Interferon, pirfenidone and other new agents may be of benefit but further studies are required. Any recommendations for treatment must therefore be made on an individual and empiric basis. As some other forms of pulmonary fibrosis may respond better to immunosuppressive agents, it remains important to make an accurate diagnosis, by open lung biopsy if necessary.

Cytokine-like factor 1 gene expression is enriched in idiopathic pulmonary fibrosis and drives the accumulation of CD4+ T cells in murine lungs: evidence for an antifibrotic role in bleomycin injury

Idiopathic pulmonary fibrosis (IPF) is a progressive and typically fatal lung disease. To gain insight into the pathogenesis of IPF, we reanalyzed our previously published gene expression data profiling IPF lungs. Cytokine receptor-like factor 1 (CRLF1) was among the most highly up-regulated genes in IPF lungs, compared with normal controls. The protein product (CLF-1) and its partner, cardiotrophin-like cytokine (CLC), function as members of the interleukin 6 (IL-6) family of cytokines. Because of earlier work implicating IL-6 family members in IPF pathogenesis, we tested whether CLF-1 expression contributes to inflammation in experimental pulmonary fibrosis. In IPF, we detected CLF-1 expression in both type II alveolar epithelial cells and macrophages. We found that the receptor for CLF-1/CLC signaling, ciliary neurotrophic factor receptor (CNTFR), was expressed only in type II alveolar epithelial cells. Administration of CLF-1/CLC to both uninjured and bleomycin-injured mice led to the pulmonary accumulation of CD4(+) T cells. We also found that CLF-1/CLC administration increased inflammation but decreased pulmonary fibrosis. CLF-1/CLC leads to significantly enriched expression of T-cell-derived chemokines and cytokines, including the antifibrotic cytokine interferon-γ. We propose that, in IPF, CLF-1 is a selective stimulus of type II alveolar epithelial cells and may potentially drive an antifibrotic response by augmenting both T-helper-1-driven and T-regulatory-cell-driven inflammatory responses in the lung.

Epidemiology and management of common pulmonary diseases in older persons

Pulmonary disease prevalence increases with age and contributes to morbidity and mortality in older patients. Dyspnea in older patients is often ascribed to multiple etiologies such as medical comorbidities and deconditioning. Common pulmonary disorders are frequently overlooked as contributors to dyspnea in older patients. In addition to negative impacts on morbidity and mortality, quality of life is reduced in older patients with uncontrolled, undertreated pulmonary symptoms. The purpose of this review is to discuss the epidemiology of common pulmonary diseases, namely pneumonia, chronic obstructive pulmonary disease, asthma, lung cancer, and idiopathic pulmonary fibrosis in older patients. We will review common clinical presentations for these diseases and highlight differences between younger and older patients. We will also briefly discuss risk factors, treatment, and mortality associated with these diseases. Finally, we will address the relationship between comorbidities, pulmonary symptoms, and quality of life in older patients with pulmonary diseases.

Evolving genomic approaches to idiopathic pulmonary fibrosis: moving beyond genes

A little more than 10 years ago, the completed sequencing of the human genome boldly promised to usher in an era of enhanced understanding and accelerated development of treatments for most human diseases. Ten years later, many of these therapeutic goals have not been reached, but genomic technologies have dramatically enhanced our understanding of how genes and gene networks contribute to the pathogenesis of disease. In this review, we describe how genomic technologies have shaped our study of idiopathic pulmonary fibrosis (IPF), a devastating, progressive scarring of the lung parenchyma, a disease without a known cause, or treatment. We frame the important genomic discoveries in IPF of the previous decade in the clinical context of establishing a diagnosis of IPF and predicting the prognosis. Gene expression profiling of peripheral blood will help identify potential biomarkers for assessing the clinical severity of IPF. We highlight the growth of epigenetic research in IPF, including the contribution of microRNAs to the pathogenesis of disease. We suggest that the full power of genomic discoveries in IPF will be realized when researchers apply these techniques prospectively in large collaborative studies across institutions, support the training of young investigators in genomics, and employ systems biology approaches to the interpretation of genomic data.

An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management

This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.

Non-steroid agents for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis is a chronic progressive lung disease with poor outcome and no effective treatment to date. This is an update of a Cochrane Review first published in 2003.

OBJECTIVES

To assess the efficacy of non-steroid agents in adults with idiopathic pulmonary fibrosis.

SEARCH STRATEGY

We searched the Cochrane Airways Group Register (30 March 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2010), Ovid MEDLINE to March week 5, 2010, EMBASE to week 13, 2010 and PubMed to April 2010, with additional handsearching, including abstracts of international conferences. We also contacted pharmaceutical companies and researchers in the field.

SELECTION CRITERIA

Randomised studies comparing non-steroid drugs with placebo or steroids in adults with idiopathic pulmonary fibrosis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and assessed risk of bias. We contacted pharmaceutical companies to obtain missing information, if any. We combined survival outcomes using Peto odds ratios or hazard ratios (HR).

MAIN RESULTS

Fifteen trials involving 10 different drugs were included. Two trials enrolling 1156 patients compared interferon gamma-1beta with placebo: interferon gamma-1beta did not significantly improve survival (HR 0.88, 95% CI 0.47 to 1.64; P = 0.68). Four trials involving 1155 patients compared pirfenidone with placebo. Three trials, conducted in 1046 patients, provided data on progression-free survival: pirfenidone significantly reduced the risk of disease progression by 30% (HR 0.70, 95% CI 0.56 to 0.88, P = 0.002). Data on the effect of pirfenidone on pulmonary function could only be assessed for two studies analysing 314 patients. Forced vital capacity or vital capacity was significantly improved by pirfenidone (mean difference 0.08 L, 95% CI 0.03 to 0.13, P = 0.0006).

AUTHORS' CONCLUSIONS

Based on available data, partly still unpublished, pirfenidone appears to improve progression-free survival and, to a lesser extent, pulmonary function in patients with idiopathic pulmonary fibrosis. More data are needed on overall survival and quality of life on treatment. From the studies in this review, interferon gamma-1beta has not been shown to affect survival. Other agents evaluated in single studies either failed to provide evidence for a benefit or need to be assessed in larger randomised controlled trials.

Clinical use of biomarkers of survival in pulmonary fibrosis

Background

Biologic predictors or biomarkers of survival in pulmonary fibrosis with a worse prognosis, more specifically in idiopathic pulmonary fibrosis would help the clinician in deciding whether or not to treat since treatment carries a potential risk for adverse events. These decisions are made easier if accurate and objective measurements of the patients' clinical status can predict the risk of progression to death.

Method

A literature review is given on different biomarkers of survival in interstitial lung disease, mainly in IPF, since this disease has the worst prognosis.

Conclusion

Serum biomarkers, and markers measured by medical imaging as HRCT, pertechnegas, DTPA en FDG-PET are not ready for clinical use to predict mortality in different forms of ILD. A baseline FVC, a change of FVC of more than 10%, and change in 6MWD are clinically helpful predictors of survival.

Treating IPF--all or nothing? A PRO-CON debate

The Idiopathic Pulmonary Fibrosis (IPF) is a progressive fibrotic lung disease with poor prognosis. It is distinct from other idiopathic interstitial pneumonias by its histopathological pattern of usual interstitial pneumonia which is characterized by accumulation of fibroblasts, extracellular matrix and honeycombing. Inflammation is only scarce in true IPF. The use of anti-inflammatory therapy is still part of guidelines for IPF management, although not specifically recommended, because convincing evidence showing beneficial effects of this approach is lacking. This review provides a summary of important arguments PRO and CON using anti-inflammatory and anti-oxidant therapy for patients with IPF in form of a debate with a concluding statement of both positions at the end.

Ecogenomics of respiratory diseases of public health significance

Gene-environment interactions are the indisputable cause of most respiratory diseases. However, we still have very limited understanding of the mechanisms that guide these interactions. Although the conceptual approaches to environmental genomics were established several decades ago, the tools are only now available to better define the mechanisms that underlie the interactions among these important etiological features of lung disease. In this article, we summarize recent insights in the environmental genomics (ecogenomics) of common nonmalignant respiratory diseases (asthma, COPD, pulmonary fibrosis, and respiratory infections), describe the framework of gene-environment interactions that inform the pathogenesis of respiratory diseases, and propose future research directions that will help translate scientific advances into public health gains.

Molecular phenotypes distinguish patients with relatively stable from progressive idiopathic pulmonary fibrosis (IPF)

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic interstitial lung disease that is unresponsive to current therapy and often leads to death. However, the rate of disease progression differs among patients. We hypothesized that comparing the gene expression profiles between patients with stable disease and those in which the disease progressed rapidly will lead to biomarker discovery and contribute to the understanding of disease pathogenesis.

METHODOLOGY AND PRINCIPAL FINDINGS

To begin to address this hypothesis, we applied Serial Analysis of Gene Expression (SAGE) to generate lung expression profiles from diagnostic surgical lung biopsies in 6 individuals with relatively stable (or slowly progressive) IPF and 6 individuals with progressive IPF (based on changes in DLCO and FVC over 12 months). Our results indicate that this comprehensive lung IPF SAGE transcriptome is distinct from normal lung tissue and other chronic lung diseases. To identify candidate markers of disease progression, we compared the IPF SAGE profiles in stable and progressive disease, and identified a set of 102 transcripts that were at least 5-fold up regulated and a set of 89 transcripts that were at least 5-fold down regulated in the progressive group (P-value</=0.05). The over expressed genes included surfactant protein A1, two members of the MAPK-EGR-1-HSP70 pathway that regulate cigarette-smoke induced inflammation, and Plunc (palate, lung and nasal epithelium associated), a gene not previously implicated in IPF. Interestingly, 26 of the up regulated genes are also increased in lung adenocarcinomas and have low or no expression in normal lung tissue. More importantly, we defined a SAGE molecular expression signature of 134 transcripts that sufficiently distinguished relatively stable from progressive IPF.

CONCLUSIONS

These findings indicate that molecular signatures from lung parenchyma at the time of diagnosis could prove helpful in predicting the likelihood of disease progression or possibly understanding the biological activity of IPF.

Perioperative management of severe interstitial pneumonia for rectal surgery: a case report

This report describes a case of rectal cancer with severe interstitial pneumonia (IP) and chronic pneumothorax. Acute exacerbation of IP is a serious postoperative complication and the consequences are extremely poor. To provide less invasive surgery and to prevent acute exacerbation of the IP, the patient received chemo-radiotherapy for controlling locally advanced tumor following low anterior resection under combined spinal-epidural anesthesia. Adequate epidural analgesia during the postoperative period had been shown and the epidural catheter was removed on the 3rd postoperative day. The patient showed symptoms of intrapelvic abscess due to the anastomotic leakage at 10th postoperative day. In order to avoid complications due to spinal and epidural anesthesia (epidural abscess, meningitis), and to prevent acute exacerbation of the IP, general anesthesia was employed with minimal fraction of inspired oxygen (FIO(2)) to perform the colostomy for the anastomotic leakage. The patient recovered without any postoperative respiratory complications. We herein report the successful perioperative management of a rectal cancer patient with severe IP and chronic pneumothorax, with special attention paid to the respiratory functions.

Comparison between conventional and "clinical" assessment of experimental lung fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a treatment resistant disease with poor prognosis. Numerous compounds have been demonstrated to efficiently prevent pulmonary fibrosis (PF) in animal models but only a few were successful when given to animals with established fibrosis. Major concerns of current PF models are spontaneous resolution and high variability of fibrosis, and the lack of assessment methods that can allow to monitor the effect of drugs in individual animals over time. We used a model of experimental PF in rats and compare parameters obtained in living animals with conventional assessment tools that require removal of the lungs.

METHODS

PF was induced in rats by adenoviral gene transfer of transforming growth factor-beta. Morphological and functional changes were assessed for up to 56 days by micro-CT, lung compliance (measured via a mechanical ventilator) and VO2max and compared to histomorphometry and hydroxyproline content.

RESULTS

Standard histological and collagen assessment confirmed the persistent fibrotic phenotype as described before. The histomorphological scores correlated both to radiological (r2 = 0.29, p < 0.01) and functional changes (r2 = 0.51, p < 0.0001). VO2max did not correlate with fibrosis.

CONCLUSION

The progression of pulmonary fibrosis can be reliably assessed and followed in living animals over time using invasive, non-terminal compliance measurements and micro-CT. This approach directly translates to the management of patients with IPF and allows to monitor therapeutic effects in drug intervention studies.

Oxidative stress and antioxidants in the pathogenesis of pulmonary fibrosis: a potential role for Nrf2

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disorder in which excessive deposition of extracellular matrix leads to irreversible scarring of interstitial lung tissue. The etiology of IPF remains unknown, but growing evidence suggests that disequilibrium in oxidant/antioxidant balance contributes significantly. IPF is currently regarded as a fibroproliferative disorder triggered by repeated alveolar epithelial cell injury. Oxidative stress plays a role in many processes involved in alveolar epithelial cell injury and fibrogenesis. Here we review the role of oxidative stress in IPF, and other forms of pulmonary fibrosis, with particular attention to antioxidant defenses regulated by the redox-sensitive transcription factor nuclear factor, erythroid derived 2, like (Nrf2). Nrf2 binds specific antioxidant response elements (AREs) in the promoter of antioxidant enzyme and defense protein genes and regulates their expression in many tissue types. Nrf2 protects from several phenotypes in which enhanced oxidative burden contributes to disease pathogenesis, including cancer, acute lung injury, and pulmonary fibrosis. We suggest that promoter polymorphisms in human NRF2 may contribute to IPF susceptibility, although this hypothesis has not been tested. Pulmonary fibrosis is a highly complex disease and involves multiple genes and processes, and new therapies for cellular and molecular targets involved in pathogenic mechanisms are needed.

Antioxidants as potential therapeutics for lung fibrosis

Interstitial lung disease encompasses a large group of chronic lung disorders associated with excessive tissue remodeling, scarring, and fibrosis. The evidence of a redox imbalance in lung fibrosis is substantial, and the rationale for testing antioxidants as potential new therapeutics for lung fibrosis is appealing. Current animal models of lung fibrosis have clear involvement of ROS in their pathogenesis. New classes of antioxidant agents divided into catalytic antioxidant mimetics and antioxidant scavengers are being developed. The catalytic antioxidant class is based on endogenous antioxidant enzymes and includes the manganese-containing macrocyclics, porphyrins, salens, and the non-metal-containing nitroxides. The antioxidant scavenging class is based on endogenous antioxidant molecules and includes the vitamin E analogues, thiols, lazaroids, and polyphenolic agents. Numerous studies have shown oxidative stress to be associated with many interstitial lung diseases and that these agents are effective in attenuating fibroproliferative responses in the lung of animals and humans.

Increased in CD8 T lymphocytes in the BAL fluid of patients with sulfur mustard gas-induced pulmonary fibrosis

OBJECTIVE

In an attempt to understand better the potential role of the T cell in the pathogenesis of pulmonary fibrosis (PF) due to sulfur mustard gas inhalation, this study was designed to analyze bronchoalveolar lavage (BAL) lymphocyte subsets and to determine the ratio of CD4 to CD8 lymphocytes in BAL fluid.

SETTING

University hospital.

PATIENTS

Twenty-one veterans with mustard gas-induced pulmonary fibrosis and 20 normal veterans as control group.

INTERVENTION

Chest roentgenograms, pulmonary function tests (PFTs), tests for carbon monoxide diffusing capacity of the lung (DLCO), high-resolution CT scans of the chest, BAL via fiberoptic bronchoscopy, analyses of BAL fluids for cellular and Flow-cytometric analysis of the phenotype of bronchoalveolar cells were performed in all cases. A transbronchial lung biopsy was done in all patients following BAL.

RESULTS

Neutrophilic alveolitis was the predominant feature. Neutrophils (P<0.0001) and eosinophils (P=0.0006) were the predominant cell types in the BAL fluid of patients with PF. CD8 lymphocytes expressed as percentage or absolute number were significantly higher in patients with PF than in healthy controls (22.96+/-7.48% vs. 14.16+/-7.73%, respectively; P=0.0006; and 2.28+/-0.84 vs. 1.10+/-0.55 x 10(3) cells/ml, respectively; P<0.0001). The CD4/CD8 ratio was significantly lower in patients with PF than in healthy controls (0.73+/-0.25 vs. 1.58+/-0.67; P<0.0001). Except for the percentage and the absolute number of the BAL fluid neutrophils (r=0.70, P=0.001: r=-0.62, P=0.005; respectively), no correlation was found between DLCO% and the other BAL cells. A significant negative correlation was observed between the percentage of DLCO and both the percentage and the absolute number of CD8 lymphocytes in BAL fluid in patients with PF (r=-0.81, P=0.0003; r=-0.61, P=0.006; respectively). A significant correlation was also seen between the percentage of DLCO and the CD4/CD8 ratio (r=-0.60, P=0.006) in our patients.

CONCLUSION

CD8 T cells in BAL fluid were significantly elevated in patients with pulmonary fibrosis. Patients with higher grades of pulmonary fibrosis expressed as percentage of DLCO, revealed higher percentages and the absolute number of CD8 T cells and a lower CD4/CD8 ratio.

Alpha-defensin enhances expression of HSP47 and collagen-1 in human lung fibroblasts

Neutrophils and lung fibroblasts are thought to play a role in the pathogenesis of pulmonary fibrosis. We reported previously that heat shock protein 47 (HSP47), a collagen-specific molecular chaperon, and collagen-1 synthesis were involved in pulmonary fibrosis, and that plasma levels of alpha-defensins (HNP; human neutrophil peptide), cationic proteins with antimicrobial and cytotoxic activity in neutrophils, were significantly higher in patients with idiopathic pulmonary fibrosis than in control subjects. Here, we investigated the direct effect of HNP-1 in vitro on the expression of HSP47 and collagen-1 in human lung fibroblasts (NHLF). HNP-1 at 5 microg/ml induced fibroblast proliferation but at concentrations >50 microg/ml, HNP-1 reduced cell viability. Incubation of NHLF with 10 to 25 microg/ml of HNP-1 for 24-h increased the expression of HSP47 and collagen-1 mRNAs (p<0.05). The levels of HSP47 protein also increased significantly at 50 microg/ml, and those of collagen-1 protein increased at 10 to 50 microg/ml of HNP-1 (p<0.05). The mitogen-activated protein kinase (MAPK) signaling pathway in NHLF was activated by HNP-1 stimulation, but inhibitor of MEK (PD98059) did not block HNP-1-induced HSP47 protein production. Our results suggest that alpha-defensin is a fibrogenic mediator that promotes collagen synthesis through the upregulation of HSP47 and collagen-1 in lung fibroblasts and participates in the pathogenesis of neutrophil-induced pulmonary fibrosis.

Matrix metalloproteinases in lung: multiple, multifarious, and multifaceted

The matrix metalloproteinases (MMPs), a family of 25 secreted and cell surface-bound neutral proteinases, process a large array of extracellular and cell surface proteins under normal and pathological conditions. MMPs play critical roles in lung organogenesis, but their expression, for the most part, is downregulated after generation of the alveoli. Our knowledge about the resurgence of the MMPs that occurs in most inflammatory diseases of the lung is rapidly expanding. Although not all members of the MMP family are found within the lung tissue, many are upregulated during the acute and chronic phases of these diseases. Furthermore, potential MMP targets in the lung include all structural proteins in the extracellular matrix (ECM), cell adhesion molecules, growth factors, cytokines, and chemokines. However, what is less known is the role of MMP proteolysis in modulating the function of these substrates in vivo. Because of their multiplicity and substantial substrate overlap, MMPs are thought to have redundant functions. However, as we explore in this review, such redundancy most likely evolved as a necessary compensatory mechanism given the critical regulatory importance of MMPs. While inhibition of MMPs has been proposed as a therapeutic option in a variety of inflammatory lung conditions, a complete understanding of the biology of these complex enzymes is needed before we can reasonably consider them as therapeutic targets.

Cell profiles of bronchoalveolar lavage fluid as prognosticators of idiopathic pulmonary fibrosis/usual interstitial pneumonia among Japanese Patients

BACKGROUND

The role of bronchoalveolar lavage fluid (BALF) cell profiles in predicting the clinical outcome of idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP) is still under discussion.

OBJECTIVE

To determine whether BALF cell profiles affect the survival of patients with UIP diagnosed by surgical lung biopsy/autopsy at the early stage of IPF.

METHODS

This hospital-based retrospective cohort study used 81 Japanese patients with histologically proven IPF/UIP who underwent BAL examination. The BALF samples were obtained from non-current smokers: NCS (n = 41) and current smokers: CS (n = 40). The Kaplan-Meier and Cox's proportional hazard methods were used to estimate the survival and evaluate the risk ratio for death in the two groups. To detect the multicollinearity, a stepwise regression was employed.

RESULTS

A slight increase in the absolute numbers of BALF neutrophils tended to relate to a decrease in the relative risk for death in NCS patients and CS patients in the univariate analysis. In stepwise regression, the increase in percent vital capacity and the increase in the BALF CD4/CD8 ratio in NCS was detected as a favorable predictor, while increased BALF cells affected the results due to chronic smoking in CS.

CONCLUSIONS

Based on the study bias of the biopsy-proven IPF/UIP patients at stable stages, an independent variable indicating a favorable outcome was an increased BALF CD4/CD8 ratio in NCS patients, while it was difficult to identify definite prognosticators in CS patients.

Racial and ethnic disparities in survival in lung transplant candidates with idiopathic pulmonary fibrosis

Minority patients have worse outcomes than nonminority patients in a variety of pulmonary diseases. We aimed to compare the survival of Black and Hispanic patients to that of others with idiopathic pulmonary fibrosis (IPF). We performed a retrospective cohort study of patients with IPF who were evaluated for lung transplantation at our center. Kaplan-Meier survival curves and Cox proportional hazards models were used to compare survival between groups. Black and Hispanic patients had spirometry, lung volumes and diffusion capacity that were similar to others, but had worse exercise capacity. Minority patients had a significantly increased risk of death compared to others independent of transplantation status (hazard ratio = 3.3, 95% CI 1.2-8.9, p = 0.02). Differences in exercise capacity, pulmonary hemodynamics and socioeconomic factors appeared to account for some of the differences in survival. Black and Hispanic patients with IPF had an increased risk of death following referral for lung transplantation. This finding may be due to differences in disease progression and/or differences in access to medical care among minority patients. Future studies should confirm our findings in a larger cohort. The elimination of racial and ethnic disparities in outcome should be a priority for clinicians and researchers in this field.

Functional predictors of exertional dyspnea, 6-min walking distance and HRCT fibrosis score in idiopathic pulmonary fibrosis

BACKGROUND

Exertional dyspnea and exercise incapacity are the most prominent and disabling symptoms and the main contributors to health-related quality of life in patients with idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

There are no comprehensive studies on pulmonary function tests (PFTs), dyspnea, exercise capacity and radiographic scores in IPF. We therefore sought to investigate the functional variables that can predict dyspnea, exercise capacity and disease extent in IPF.

METHODS

Thirty-four patients with IPF according to the ATS/ERS criteria underwent PFTs, Medical Research Council (MRC) dyspnea scoring, 6-min walking distance (6-MWD) and radiographic evaluation of fibrosis (HRCT score).

RESULTS

The 6-MWD (% pred.) was more impaired than PFTs. Residual volume (RV) showed the best correlation with the extent of fibrosis (r = -0.67, p = 0.0001) and, together with the alveolar-arterial gradient for O(2) [DeltaP(A - a)O(2)], was an independent predictor of disease extent (R(2) = 0.44). PFTs showed significant though weak correlations with MRC score and 6-MWD. According to the regression analysis, DL(CO) and the HRCT fibrosis score were independent predictors of dyspnea, though they explained only 28% of the overall variance. FEV(1) and DeltaP(A - a)O(2) were independent predictors of 6-MWD (R(2) = 0.31).

CONCLUSIONS

PFTs and lung volumes in particular are closely related to the HRCT score, a measure of the extent of IPF. The correlation of dyspnea score and 6-MWD to PFTs is limited, due to the complexity of mechanisms leading to exercise limitation in IPF. Therefore dyspnea and exercise performance are largely independent indices and should be followed together with PFTs and HRCT score in order to better assess the status and progress of IPF patients.

Clinical and pathologic features of familial interstitial pneumonia

RATIONALE

Several lines of evidence suggest that genetic factors and environmental exposures play a role in the development of pulmonary fibrosis.

OBJECTIVES

We evaluated families with 2 or more cases of idiopathic interstitial pneumonia among first-degree family members (familial interstitial pneumonia, or FIP), and identified 111 families with FIP having 309 affected and 360 unaffected individuals.

METHODS

The presence of probable or definite FIP was based on medical record review in 28 cases (9.1%); clinical history, diffusing capacity of carbon monoxide (DL(CO)), and chest X-ray in 16 cases (5.2%); clinical history, DL(CO), and high-resolution computed tomography chest scan in 191 cases (61.8%); clinical history and surgical lung biopsy in 56 cases (18.1%); and clinical history and autopsy in 18 cases (5.8%).

RESULTS

Older age (68.3 vs. 53.1; p < 0.0001), male sex (55.7 vs. 37.2%; p < 0.0001), and having ever smoked cigarettes (67.3 vs. 34.1%; p < 0.0001) were associated with the development of FIP. After controlling for age and sex, having ever smoked cigarettes remained strongly associated with the development of FIP (odds ratio(adj), 3.6; 95% confidence interval, 1.3-9.8). Evidence of aggregation of disease was highly significant (p < 0.001) among sibling pairs, and 20 pedigrees demonstrated vertical transmission, consistent with autosomal dominant inheritance. Forty-five percent of pedigrees demonstrated phenotypic heterogeneity, with some pedigrees demonstrating several subtypes of idiopathic interstitial pneumonia occurring within the same families.

CONCLUSIONS

These findings suggest that FIP may be caused by an interaction between a specific environmental exposure and a gene (or genes) that predisposes to the development of several subtypes of idiopathic interstitial pneumonia.

Imaging Considerations: Interstitial Lung Disease in Children

This article provides a guide for the technique and interpretation of high-resolution chest CT of diffuse lung disease in children. Specific causes of diffuse lung disease in infants and children are reviewed as a guide to the interpretation of these images. New information, particularly the identification of surfactant protein mutations, is included. The idiopathic interstitial pneumonia classification, which is frequently applied to pediatric lung biopsy specimens, is also discussed.

The diabetic lung: relevance of alveolar microangiopathy for the use of inhaled insulin

The alveolar-capillary network receives the entire cardiac output and constitutes the largest microvascular organ in the body, making it highly susceptible to systemic microangiopathy. Owing to its large reserves, symptoms and disability develop later in the lung than in smaller microvasculature such as the kidney or retina despite a comparable severity of anatomic involvement. Hence, pulmonary impairment in diabetes mellitus is under-recognized. Nonetheless, respiratory autonomic neuropathy and structural derangement of the thorax and lung parenchyma develop in many asymptomatic diabetic patients; the pathophysiology parallels that in other target organs. Even subclinical loss of alveolar microvascular reserves can be quantified noninvasively from lung diffusing capacity and its components (membrane diffusing capacity and alveolar-capillary blood volume) measured at a given cardiac output at rest or during exercise. The alveolar diffusion-perfusion relation tracks the recruitment of microvascular reserves in a manner independent of physical fitness. This article addresses the importance and pathophysiologic basis of diabetic pulmonary involvement, the assessment of diabetic alveolar microangiopathy, and the relevance of this understanding for the emerging use of inhaled insulin.