Etiology Of Idiopathic Pulmonary Fibrosis Research Articles

Genetics and Genomics of Pulmonary Fibrosis: Charting the Molecular Landscape and Shaping Precision Medicine.

Recent genetic and genomic advancements have elucidated the complex etiology of idiopathic pulmonary fibrosis (IPF) and other progressive fibrotic interstitial lung diseases (ILDs), emphasizing the contribution of heritable factors. This state-of-the-art review synthesizes evidence on significant genetic contributors to pulmonary fibrosis (PF), including rare genetic variants and common SNPs. The MUC5B promoter variant is unusual, a common SNP that markedly elevates the risk of early and established PF. We address the utility of genetic variation in enhancing understanding of disease pathogenesis and clinical phenotypes, improving disease definitions, and informing prognosis and treatment response. Critical research gaps are highlighted, particularly the underrepresentation of non-European ancestries in PF genetic studies and the exploration of PF phenotypes beyond usual interstitial pneumonia/IPF. We discuss the role of telomere length, often critically short in PF, and its link to progression and mortality, underscoring the genetic complexity involving telomere biology genes (TERT, TERC) and others like SFTPC and MUC5B. In addition, we address the potential of gene-by-environment interactions to modulate disease manifestation, advocating for precision medicine in PF. Insights from gene expression profiling studies and multiomic analyses highlight the promise for understanding disease pathogenesis and offer new approaches to clinical care, therapeutic drug development, and biomarker discovery. Finally, we discuss the ethical, legal, and social implications of genomic research and therapies in PF, stressing the need for sound practices and informed clinical genetic discussions. Looking forward, we advocate for comprehensive genetic testing panels and polygenic risk scores to improve the management of PF and related ILDs across diverse populations.

Role of telomere dysfunction and immune infiltration in idiopathic pulmonary fibrosis: new insights from bioinformatics analysis.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease characterized by unexplained irreversible pulmonary fibrosis. Although the etiology of IPF is unclear, studies have shown that it is related to telomere length shortening. However, the prognostic value of telomere-related genes in IPF has not been investigated. We utilized the GSE10667 and GSE110147 datasets as the training set, employing differential expression analysis and weighted gene co-expression network analysis (WGCNA) to screen for disease candidate genes. Then, we used consensus clustering analysis to identify different telomere patterns. Next, we used summary data-based mendelian randomization (SMR) analysis to screen core genes. We further evaluated the relationship between core genes and overall survival and lung function in IPF patients. Finally, we performed immune infiltration analysis to reveal the changes in the immune microenvironment of IPF. Through differential expression analysis and WGCNA, we identified 35 significant telomere regulatory factors. Consensus clustering analysis revealed two distinct telomere patterns, consisting of cluster A (n = 26) and cluster B (n = 19). Immune infiltration analysis revealed that cluster B had a more active immune microenvironment, suggesting its potential association with IPF. Using GTEx eQTL data, our SMR analysis identified two genes with potential causal associations with IPF, including GPA33 (PSMR = 0.0013; PHEIDI = 0.0741) and MICA (PSMR = 0.0112; PHEIDI = 0.9712). We further revealed that the expression of core genes is associated with survival time and lung function in IPF patients. Finally, immune infiltration analysis revealed that NK cells were downregulated and plasma cells and memory B cells were upregulated in IPF. Further correlation analysis showed that GPA33 expression was positively correlated with NK cells and negatively correlated with plasma cells and memory B cells. Our study provides a new perspective for the role of telomere dysfunction and immune infiltration in IPF and identifies potential therapeutic targets. Further research may reveal how core genes affect cell function and disease progression, providing new insights into the complex mechanisms of IPF.

Deciphering the mediating role of CXCL10 in hypothyroidism-induced idiopathic pulmonary fibrosis in European ancestry: a Mendelian randomization study.

Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease characterized by progressive fibrosis, leading to impaired gas exchange and high mortality. The etiology of IPF is complex, with potential links to autoimmune disorders such as hypothyroidism. This study explores the relationship between hypothyroidism and IPF, focusing on the mediating role of plasma proteins. A two-sample Mendelian randomization (MR) approach was employed to determine the impact of hypothyroidism on IPF and the mediating role of 4,907 plasma proteins, all in individuals of European ancestry. Sensitivity analyses, external validation, and reverse causality tests were conducted to ensure the robustness of the findings. Additionally, the function of causal SNPs was evaluated through gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The findings suggest that hypothyroidism, through altered plasma protein expression, particularly CXCL10, may contribute to the pathogenesis of IPF. This novel insight highlights the potential of CXCL10 as a therapeutic target in IPF, especially in patients with hypothyroidism. The study emphasizes the need for further research into the complex interplay between autoimmune disorders and IPF, with a view towards developing targeted interventions for IPF management.

Autocrine TGF-β-positive feedback in profibrotic AT2-lineage cells plays a crucial role in non-inflammatory lung fibrogenesis

The molecular etiology of idiopathic pulmonary fibrosis (IPF) has been extensively investigated to identify new therapeutic targets. Although anti-inflammatory treatments are not effective for patients with IPF, damaged alveolar epithelial cells play a critical role in lung fibrogenesis. Here, we establish an organoid-based lung fibrosis model using mouse and human lung tissues to assess the direct communication between damaged alveolar type II (AT2)-lineage cells and lung fibroblasts by excluding immune cells. Using this in vitro model and mouse genetics, we demonstrate that bleomycin causes DNA damage and activates p53 signaling in AT2-lineage cells, leading to AT2-to-AT1 transition-like state with a senescence-associated secretory phenotype (SASP). Among SASP-related factors, TGF-β plays an exclusive role in promoting lung fibroblast-to-myofibroblast differentiation. Moreover, the autocrine TGF-β-positive feedback loop in AT2-lineage cells is a critical cellular system in non-inflammatory lung fibrogenesis. These findings provide insights into the mechanism of IPF and potential therapeutic targets.

UBQLN1 deficiency mediates telomere shortening and IPF through interacting with RPA1.

Premature telomere shortening is a known factor correlated to idiopathic pulmonary fibrosis (IPF) occurrence, which is a chronic, progressive, age-related disease with high mortality. The etiology of IPF is still unknown. Here, we found that UBQLN1 plays a key role in telomere length maintenance and is potentially relevant to IPF. UBQLN1 involves in DNA replication by interacting with RPA1 and shuttling it off from the replication fork. The deficiency of UBQLN1 retains RPA1 at replication fork, hinders replication and thus causes cell cycle arrest and genome instability. Especially at telomere regions of the genome, where more endogenous replication stress exists because of G rich sequences, UBQLN1 depletion leads to rapid telomere shortening in HeLa cells. It revealed that UBQLN1 depletion also shortens telomere length at mouse lung and accelerates mouse lung fibrosis. In addition, the UBQLN1 expression level in IPF patients is downregulated and correlated to poor prognosis. Altogether, these results uncover a new role of UBQLN1 in ensuring DNA replication and maintaining telomere stability, which may shed light on IPF pathogenesis and prevention.

Lipid metabolism in idiopathic pulmonary fibrosis: From pathogenesis to therapy.

Idiopathic pulmonary fibrosis (IPF) is a chronic irreversible interstitial lung disease characterized by a progressive decline in lung function. The etiology of IPF is unknown, which poses a significant challenge to the treatment of IPF. Recent studies have identified a strong association between lipid metabolism and the development of IPF. Qualitative and quantitative analysis of small molecule metabolites using lipidomics reveals that lipid metabolic reprogramming plays a role in the pathogenesis of IPF. Lipids such as fatty acids, cholesterol, arachidonic acid metabolites, and phospholipids are involved in the onset and progression of IPF by inducing endoplasmic reticulum stress, promoting cell apoptosis, and enhancing the expression of pro-fibrotic biomarkers. Therefore, targeting lipid metabolism can provide a promising therapeutic strategy for pulmonary fibrosis. This review focuses on lipid metabolism in the pathogenesis of pulmonary fibrosis.

Research Progress in the Molecular Mechanisms, Therapeutic Targets, and Drug Development of Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease. Recent studies have identified the key role of crosstalk between dysregulated epithelial cells, mesenchymal, immune, and endothelial cells in IPF. In addition, genetic mutations and environmental factors (e.g., smoking) have also been associated with the development of IPF. With the recent development of sequencing technology, epigenetics, as an intermediate link between gene expression and environmental impacts, has also been reported to be implicated in pulmonary fibrosis. Although the etiology of IPF is unknown, many novel therapeutic targets and agents have emerged from clinical trials for IPF treatment in the past years, and the successful launch of pirfenidone and nintedanib has demonstrated the promising future of anti-IPF therapy. Therefore, we aimed to gain an in-depth understanding of the underlying molecular mechanisms and pathogenic factors of IPF, which would be helpful for the diagnosis of IPF, the development of anti-fibrotic drugs, and improving the prognosis of patients with IPF. In this study, we summarized the pathogenic mechanism, therapeutic targets and clinical trials from the perspective of multiple cell types, gene mutations, epigenetic and environmental factors.

Colocalization of Gene Expression and DNA Methylation with Genetic Risk Variants Supports Functional Roles of MUC5B and DSP in Idiopathic Pulmonary Fibrosis.

Rationale: Common genetic variants have been associated with idiopathic pulmonary fibrosis (IPF). Objectives: To determine functional relevance of the 10 IPF-associated common genetic variants we previously identified. Methods: We performed expression quantitative trait loci (eQTL) and methylation quantitative trait loci (mQTL) mapping, followed by co-localization of eQTL and mQTL with genetic association signals and functional validation by luciferase reporter assays. Illumina multi-ethnic genotyping arrays, mRNA sequencing, and Illumina 850k methylation arrays were performed on lung tissue of participants with IPF (234 RNA and 345 DNA samples) and non-diseased controls (188 RNA and 202 DNA samples). Measurements and Main Results: Focusing on genetic variants within 10 IPF-associated genetic loci, we identified 27 eQTLs in controls and 24 eQTLs in cases (false-discovery-rate-adjusted P < 0.05). Among these signals, we identified associations of lead variants rs35705950 with expression of MUC5B and rs2076295 with expression of DSP in both cases and controls. mQTL analysis identified CpGs in gene bodies of MUC5B (cg17589883) and DSP (cg08964675) associated with the lead variants in these two loci. We also demonstrated strong co-localization of eQTL/mQTL and genetic signal in MUC5B (rs35705950) and DSP (rs2076295). Functional validation of the mQTL in MUC5B using luciferase reporter assays demonstrates that the CpG resides within a putative internal repressor element. Conclusions: We have established a relationship of the common IPF genetic risk variants rs35705950 and rs2076295 with respective changes in MUC5B and DSP expression and methylation. These results provide additional evidence that both MUC5B and DSP are involved in the etiology of IPF.

Lenalidomide attenuates post-inflammation pulmonary fibrosis through blocking NF-κB signaling pathway

Idiopathic pulmonary fibrosis (IPF) is a pathological consequence of interstitial pulmonary diseases, and is characterized by the persistence of fibroblasts and excessive deposition of extracellular matrix (ECM). The etiology of IPF is multifactorial. Although the role of inflammation in fibrogenesis is controversial, it is still recognized as an important component and epiphenomenon of IPF. Stimulus increase production of pro-inflammatory cytokines and activation of NF-κB, which will further promote inflammation response and myofibroblast transition. Lenalidomide is an immunomodulatory drug. Previous studies have revealed its anti-tumor effects through regulating immune response. Here we investigate the effect of lenalidomide on post-inflammation fibrosis. In vitro study revealed that lenalidomide inhibited NF-κB signaling in LPS-induced macrophage, and further attenuated macrophage-induced myofibroblast activation. Meanwhile, lenalidomide could inhibit TGF-β1-induced myofibroblast activation through suppressing TGF-β1 downstream MAPK signaling. In vivo study showed that lenalidomide inhibited pro-inflammatory cytokines TNF-α and IL-6 while enhanced anti-fibrotic cytokines IFN-γ and IL-10 in bleomycin-induced inflammation model, and attenuated pulmonary fibrosis and collagen deposition in the following fibrosis stage. In conclusion, our results demonstrate that lenalidomide possesses potential anti-fibrotic effects through suppressing NF-κB signaling.

The function of non-coding RNAs in idiopathic pulmonary fibrosis.

Non-coding ribonucleic acids (ncRNAs) are a diverse group of RNA molecules that are mostly not translated into proteins after transcription, including long non-coding RNAs (lncRNAs) with longer than 200 nucleotides non-coding transcripts and microRNAs (miRNAs) which are only 18–22 nucleotides. As families of evolutionarily conserved ncRNAs, lncRNAs activate and repress genes via a variety of mechanisms at both transcriptional and translational levels, whereas miRNAs regulate protein-coding gene expression mainly through mRNA silencing. ncRNAs are widely involved in biological functions, such as proliferation, differentiation, migration, angiogenesis, and apoptosis. Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis. The etiology of IPF is still unclear. Increasing evidence shows the close correlations between the development of IPF and aberrant expressions of ncRNAs than thought previously. In this study, we provide an overview of ncRNAs participated in pathobiology of IPF, seeking the early diagnosis biomarker and aiming for potential therapeutic applications for IPF.

Therapeutic targeting of 15-PGDH in murine pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by interstitial remodeling and pulmonary dysfunction. The etiology of IPF is not completely understood but involves pathologic inflammation and subsequent failure to resolve fibrosis in response to epithelial injury. Treatments for IPF are limited to anti-inflammatory and immunomodulatory agents, which are only partially effective. Prostaglandin E2 (PGE2) disrupts TGFβ signaling and suppresses myofibroblast differentiation, however practical strategies to raise tissue PGE2 during IPF have been limited. We previously described the discovery of a small molecule, (+)SW033291, that binds with high affinity to the PGE2-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and increases PGE2 levels. Here we evaluated pulmonary 15-PGDH expression and activity and tested whether pharmacologic 15-PGDH inhibition (PGDHi) is protective in a mouse model of bleomycin-induced pulmonary fibrosis (PF). Long-term PGDHi was well-tolerated, reduced the severity of pulmonary fibrotic lesions and extracellular matrix remodeling, and improved pulmonary function in bleomycin-treated mice. Moreover, PGDHi attenuated both acute inflammation and weight loss, and decreased mortality. Endothelial cells and macrophages are likely targets as these cell types highly expressed 15-PGDH. In conclusion, PGDHi ameliorates inflammatory pathology and fibrosis in murine PF, and may have clinical utility to treat human disease.

Bioinformatics Analysis Identifies Potential Key Genes of Peripheral Blood Mononuclear Cell in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic interstitial pneumonia with progressive worsening of dyspnea and lung function. The etiology of IPF is unknown, and the pathogenesis remains unclear. Our study aimed to investigate the key genes of the peripheral blood mononuclear cell in IPF by bioinformatics analysis. Our study used the online Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE28042 to identify differentially expressed genes (DEGs) between IPF patients and healthy controls. We performed the Gene Ontology (GO) and pathway enrichment analyses of genes for annotation, visualization, and integrated discovery. The STRING database constructed Protein-protein interaction (PPI) network analysis, and hub genes were identified by the CytoHubba plugin. Moreover, we used the receiver operating characteristic (ROC) curve to assess the diagnostic value of the hub genes. In total, 28 upregulated and 44 downregulated genes were identified in the differential expression analysis. The protein-protein interaction network (PPI) was established with 69 nodes and 68 edges. The top 10 hub genes were JUN, FOS, STAT3, SOCS3, JUNB, DUSP1, IL4, FCER1A, MS4A2, and CPA3. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched for the important module containing hub genes contained Fc epsilon RI signaling pathway, TNF signaling pathway, Jak-STAT signaling pathway, and MAPK signaling pathway. Additionally, the identified hub genes show high functional similarity and diagnostic value in IPF. Our study used bioinformatics analysis to provide new insight into the mechanisms underlying IPF. However, more experiments are needed to explore the relationships between the top 10 hub genes and IPF in the future.

IgA Antibodies Directed Against Citrullinated Protein Antigens Are Elevated in Patients With Idiopathic Pulmonary Fibrosis

The etiology of idiopathic pulmonary fibrosis (IPF) is unknown. Because it shares genetic, histopathologic, and radiographic features with the fibrosing interstitial lung disease seen in rheumatoid arthritis (RA), the goal of this study was to investigate RA-related autoantibodies in IPF. The study included patients with IPF from two separate cohorts at National Jewish Health and Brigham Women's Hospital (n= 181), general population control subjects (n= 160), and control subjects with disease (n= 86 [40 with RA-usual interstitial pneumonia and 46 with hypersensitivity pneumonitis]). Serum was tested for RA-associated antibodies (including IgG and IgA) to citrullinated protein antigens (ACPA). Lung tissue in 11 patients with IPF was examined for ectopic lymphoid aggregates. An increased prevalence of ACPA positivity was found in two separate IPF cohorts. In particular, positivity for IgA-ACPA was increased in these two IPF cohorts compared with general population control subjects (21.3%and 24.8%vs5.6%; P< .01). Patients with IPF were more likely to be IgA-ACPA-positive than IgG-ACPA-positive (23.2%vs8.3%; P< .01), whereas patients with RA were more likely to be IgG-ACPA-positive than IgA-ACPA-positive (72.5%vs52.5%; P= .04). There was a strong correlation between IgA-ACPA level and the number of ectopic lymphoid aggregates on lung histologic examination in IPF (r= 0.72; P= .01). In this study, IgA-ACPA was elevated in patients with IPF and correlated with lymphoid aggregates in the lung, supporting the theory that IgA-ACPA may play a role in lung disease pathogenesis in a subset of individuals with IPF. Future studies are needed to determine whether this subset of ACPA-positive patients with IPF is distinct from patients with IPF but without antibodies.

Glycogen Synthase Kinase-3\u03b2 Inhibition with 9-ING-41 Attenuates the Progression of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with a median survival of 3 years after diagnosis. Although the etiology of IPF is unknown, it is characterized by extensive alveolar epithelial cell apoptosis and proliferation of myofibroblasts in the lungs. While the origins of these myofibroblast appear to be diverse, fibroblast differentiation contributes to expansion of myofibroblasts and to disease progression. We found that agents that contribute to neomatrix formation and remodeling in pulmonary fibrosis (PF); TGF-β, Factor Xa, thrombin, plasmin and uPA all induced fibroblast/myofibroblast differentiation. These same mediators enhanced GSK-3β activation via phosphorylation of tyrosine-216 (p-Y216). Inhibition of GSK-3β signaling with the novel inhibitor 9-ING-41 blocked the induction of myofibroblast markers; α-SMA and Col-1 and reduced morphological changes of myofibroblast differentiation. In in vivo studies, the progression of TGF-β and bleomycin mediated PF was significantly attenuated by 9-ING-41 administered at 7 and 14 days respectively after the establishment of injury. Specifically, 9-ING-41 treatment significantly improved lung function (compliance and lung volumes; p < 0.05) of TGF-β adenovirus treated mice compared to controls. Similar results were found in mice with bleomycin-induced PF. These studies clearly show that activation of the GSK-3β signaling pathway is critical for the induction of myofibroblast differentiation in lung fibroblasts ex vivo and pulmonary fibrosis in vivo. The results offer a strong premise supporting the continued investigation of the GSK-3β signaling pathway in the control of fibroblast-myofibroblast differentiation and fibrosing lung injury. These data provide a strong rationale for extension of clinical trials of 9-ING-41 to patients with IPF.

Investigation of Fungal Colonization Among Iranian Patients with Idiopathic Pulmonary Fibrosis; Molecular Identification and Antifungal Susceptibility Pattern

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. In patients with lung tissue damage, fungal colonization leads to persistent infection. It is expected for there to be an association between fungal agents and etiology of IPF. Objectives: The aim of this study was to investigate the prevalence and molecular identification of fungal species isolated from IPF patients for the first time in Iran. Also, in vitro anti-fungal susceptibility testing of isolates was demonstrated. Methods: Forty nasopharyngeal (NP) swabs or bronchoalveolar lavage (BAL) samples were obtained from Iranian patients with IPF, who were diagnosed by a sophisticated practitioner from year 2015 to 2016 (Tehran, Iran). Direct examination of samples was carried out using hydroxide potassium (KOH) for detection of fungal elements. The specimens were cultured on Sabauroud Dextrose Agar (SDA) medium. Conventional methods, including polymerase chain reaction (PCR) and sequencing, were carried out for identification of fungal species. Indeed, antifungal susceptibility testing of yeast isolates was conducted according to Clinical Laboratory Standards Institute (CLSI M27- S3 and S4) protocol. The data was analysed using SPSS sofware version 20. Results: Of 40 IPF patients, 22 (55%) were female and 18 (45%) were male. Seven (17.5%) of IPF patients were positive for fungal species as follows; four (10%) Candida albicans (C. albicans), two (5%) Candida glabrata (C. glabrata), and one (2.5%) Aspergillus fumigatus (A. fumigatus) were identified using the culture and PCR technique. A significant correlation was found between C. albicans colonization in upper respiratory system tract and presence of underlying disease in IPF patients (P < 0.05). Antifungal susceptibility testing showed that all C. albicans isolates were resistant to itraconazole, whereas three (75%) C. albicans were resistant to amphoterecin B. It was found that three (75%) and one (25%) C. albicans isolate were susceptible dose dependantly and resistant to fluconazole, respectively. Morever, C. glabrata isolates were resistant to fluconazole, itraconazole, and amphotricin B. Conclusions: Taken together, fungal species were detected in 17.5% of IPF patients. Resistance of Candida species to antifungal agents is growing, therefore isolation, identification, and antifungal susceptibility testing of fungal elements in IPF patients are necessary for appropriate treatment. However, determining an association between the fungal agents and devasting form of pulmonary fibrosis requires further investigation in the future.

Evaluation of potential anti-fibrotic effect of oleuropein on bleomycin-induced pulmonary fibrosis in rat

The etiology of idiopathic pulmonary fibrosis (IPF) is not well known, however it is a final response of frequent injuries to endothelial and epithelial cells that cause influx of the inflammatory cells. Bleomycin (BLM), a chemotherapeutic agent that causes lung fibrosis in human patients has been applied extensively in rodent models to inducing IPF. Moreover, oxidative stress and production of reactive oxygen species (ROS) have been involved in the pathogenesis. We aimed to investigate the effect of main olive antioxidant and anti-inflammatory polyphenol constituent, oleuropein (OLE), on BLM-induced fibrosis model. Female Wistar rats were divided into six groups (n = 8). In this study, whereas negative group only received vehicle and treatment groups received OLE (20, 40, and 80 mg kg−1) orally. Also, positive control group received intratracheally (IT), single dose BLM (7.5 U kg−1), prednisolone (10 mg/kg) as standard cure a week before and 3 weeks after IT-BLM. At 21th day of experiment, IL-13, TNF, TGF-β, and PDGF in the bronchoalveolar fluid (BALF), lung content hydroxyproline (HP), and malondialdehyde (MDA) were quantified. Histopathological changes in lungs were investigated too. IL-13, TNF, TGF-β1, PDGF in BALF, lung HP (collagen index), and MDA content in BLM-injected group was significantly higher than the control group (p < .05). In contrast, rats treated with OLE showed obviously lesser contents. Also, the histopathological observation confirms these findings. The results indicate that treatment by OLE may inhibit production of anti-inflammatory cytokines and ROS, and thus could be a useful medicine for managing fingagin disorders.

P-229 - Effects of pirfenidone on rat alveolar macrophage skewing and macrophage-fibroblast interactions

Purpose The etiology of idiopathic pulmonary fibrosis (IPF) is still largely unknown. Pirfenidone (PFD) is a representative medication for IPF, although its anti-fibrotic mechanism is unclear. Macrophages (Mφ) polarize to the M1 type in the acute inflammation phase, and the M2 type in the chronic fibrosis phase, which has important implications in the design of Mφ-targeted therapy for IPF. This study investigated the effects of pre- or post-treatment with PFD on skewing Mφ and Mφ-fibroblast interactions. Method Rat alveolar Mφ (NR8383) were stimulated in vitro with LPS (5 ng/ml) and IFN-γ (10 U/ml), or IL-4 and IL -13 (10 ng/ml each) to induce M1 and M2 phenotypes, respectively.PFD (10 or 100 µg/ml) was added at 24 h before or after 8 h for each stimulation. Expression of M1 and M2 markers was assessed by western blotting after 24 h in M1/M2-polarized Mφ. Results Stimulation by LPS+IFN-γ or IL-4+IL-13 significantly enhanced M1 and M2 marker expression, respectively. PFD pre-treatment significantly and dose-dependently reduced M2 marker expression, whereas it showed no significant effect on M1 marker expression. PFD treatment after M2 stimulation resulted in slightly decreased M2 marker expression. Conclusion PFD pre-treatment suppressed polarization to M2 Mφ.

SIngle and Double Lung Transplantation in Idiopathic Pulmonary Fibrosis: A Review of Pulmonary Artery Mean Pressure

Majority of the patients that undergoes either single (SLT) or double (DLT) lung transplantation has an etiology of Idiopathic pulmonary fibrosis (IPF) with variable degrees of pulmonary hypertension (PH). Many of these patients has a large range of mean pulmonary artery pressure (PAP mean). We investigated the survival outcome of SLT vs. DLT in IPF patients with PAP mean of <25, >26-30, >31-35, >36-40, >41 mmHg.

Idiopathic Pulmonary Fibrosis: Aging, Mitochondrial Dysfunction, and Cellular Bioenergetics.

At present, the etiology of idiopathic pulmonary fibrosis (IPF) remains elusive. Over the past two decades, however, researchers have identified and described the underlying processes that result in metabolic dysregulation, metabolic reprogramming, and mitochondrial dysfunction observed in the cells of IPF lungs. Metabolic changes and mitochondrial dysfunction in IPF include decreased efficiency of electron transport chain function with increasing production of reactive oxygen species, decreased mitochondrial biogenesis, and impaired mitochondrial macroautophagy, a key pathway for the removal of dysfunctional mitochondria. Metabolic changes in IPF have potential impact on lung cell function, differentiation, and activation of fibrotic responses. These alterations result in activation of TGF-β and predispose to the development of pulmonary fibrosis. IPF is a disease of the aged, and many of these same bioenergetic changes are present to a lesser extent with normal aging, raising the possibility that these anticipated alterations in metabolic processes play important roles in creating susceptibility to the development of IPF. This review explores what is known regarding the cellular metabolic and mitochondrial changes that are found in IPF, and examines this body of literature to identify future research direction and potential points of intervention in the pathogenesis of IPF.

122 - Pirfenidone Suppresses Pulmonary Fibrosis Through Regulation of Alveolar Macrophage Polarization

Purpose The etiology of idiopathic pulmonary fibrosis (IPF) is still largely unknown and effective treatment is difficult. Pirfenidone (PFD) is a representative medication used to treat IPF, although its anti-fibrotic mechanism is unclear. Researchers reported PFD (> 100 µg/ml) significantly suppressed fibroblast growth in vitro. However, clinically, the Cmax of PFD in the blood is approximately 10 µg/ml. From this discrepancy, we hypothesized that there might be an additional mechanism of PFD action besides the direct effect on fibroblasts. Macrophages (Mϕ) control fibrosis via the regulation of M1/M2 polarization. M1 Mϕ exhibit proinflammatory properties, whereas M2 Mϕ promote fibrogenesis and tissue remodeling. Therefore, the aim of this study was to investigate the effects of PFD on M1/M2 polarization. Method Rat alveolar Mϕ (NR8383) were stimulated in vitro with LPS (5 ng/ml) and IFN-γ (10 U/ml), or IL-10 (10 ng/ml) to induce M1 and M2 phenotypes, respectively. Expression of M1 markers, iNOS, SOCS3 and TNF-α, and M2 markers, mannose receptor and arginase-1, was assessed by western blotting after 24 hours in the absence or presence of PFD (10, 100 µg/ml). Additionally, 7-week-old male Wistar rats were randomly divided into sham, bleomycin (BLM), 10 and 100 mg/kg PFD groups. Following intratrachial instillation of BLM (3 mg/kg) or saline, rats were orally administered PFD daily. Rats were killed at 14 days post-BLM and the polarization of Mϕ in pulmonary tissues analyzed. Results Treatment with LPS+INF-γ or IL-10 significantly increased the level of M1 or M2 markers respectively. PFD significantly reduced M2 marker expression at both 10 and 100 µg/ml, whereas it showed no significant effect on M1 marker expression. Moreover, M2 marker expression was increased in the rats of the BLM-treated groups. Notably, the level of M2 markers decreased significantly in the 10 and 100 mg/kg PFD groups compared with that of the BLM groups. Conclusions These results suggest PFD suppresses lung fibrosis through regulation of M2 Mp at clinically relevant concentrations.