Lung transplantation in idiopathic pulmonary fibrosis

Targeting iron-metabolism:a potential therapeutic strategy for pulmonary fibrosis

Iron homeostasisis is integral to normal physiological and biochemical processes of lungs. The maintenance of iron homeostasis involves the process of intake, storage and output, dependening on iron-regulated protein/iron response element system to operate tightly metabolism-related genes, including TFR1, DMT1, Fth, and FPN. Dysregulation of iron can lead to iron overload, which increases the virulence of microbial colonisers and the occurrence of oxidative stress, causing alveolar epithelial cells to undergo necrosis and apoptosis, and form extracellular matrix. Accumulated iron drive iron-dependent ferroptosis to exacerbated pulmonary fibrosis. Notably, the iron chelator deferoxamine and the lipophilic antioxidant ferritin-1 have been shown to attenuate ferroptosis and inhibit lipid peroxidation in pulmonary fibrosis. The paper summarises the regulatory mechanisms of dysregulated iron metabolism and ferroptosis in the development of pulmonary fibrosis. Targeting iron metabolism may be a potential therapeutic strategy for the prevention and treatment of pulmonary fibrosis.

Circular RNAs and their roles in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease with limited treatment options. Circular RNAs (circRNAs) have emerged as a novel class of non-coding RNAs with diverse functions in cellular processes. This review paper aims to explore the potential involvement of circRNAs in the pathogenesis of IPF and their diagnostic and therapeutic implications. We begin by providing an overview of the epidemiology and risk factors associated with IPF, followed by a discussion of the pathophysiology underlying this complex disease. Subsequently, we delve into the history, types, biogenesis, and functions of circRNAs and then emphasize their regulatory roles in the pathogenesis of IPF. Furthermore, we examine the current methodologies for detecting circRNAs and explore their diagnostic applications in IPF. Finally, we discuss the potential utility of circRNAs in the treatment of IPF. In conclusion, circRNAs hold great promise as novel biomarkers and therapeutic targets in the management of IPF.

Pyroptosis-related signatures predict immune characteristics and prognosis in IPF

The purpose of this work was to use integrated bioinformatics analysis to screen for pyroptosis-related genes (PRGs) and possible immunological phenotypes linked to the development and course of IPF. Transcriptome sequencing datasets GSE70866, GSE47460 and GSE150910 were obtained from GEO database. From the GSE70866 database, 34 PRGs with differential expression were found in IPF as compared to healthy controls. In addition, a diagnostic model containing 4 genes PRGs (CAMP, MKI67, TCEA3 and USP24) was constructed based on LASSO logistic regression. The diagnostic model showed good predictive ability to differentiate between IPF and healthy, with ROC-AUC ranging from 0.910 to 0.997 in GSE70866 and GSE150910 datasets. Moreover, based on a combined cohort of the Freiburg and the Siena cohorts from GSE70866 dataset, we identified ten PRGs that might predict prognosis for IPF. We constructed a prognostic model that included eight PRGs (CLEC5A, TREM2, MMP1, IRF2, SEZ6L2, ADORA3, NOS2, USP24) by LASSO Cox regression and validated it in the Leuven cohort. The risk model divided IPF patients from the combined cohort into high-risk and low-risk subgroups. There were significant differences between the two subgroups in terms of IPF survival and GAP stage. There is a close correlation between leukocyte migration, plasma membrane junction, and poor prognosis in a high-risk subgroup. Furthermore, a high-risk score was associated with more plasma cells, activated NK cells, monocytes, and activated mast cells. Additionally, we identified HDAC inhibitors in the cMAP database that might be therapeutic for IPF. To summarize, pyroptosis and its underlying immunological features are to blame for the onset and progression of IPF. PRG-based predictive models and drugs may offer new treatment options for IPF.

Integrated bioinformatics analysis for the identification of idiopathic pulmonary fibrosis-related genes and potential therapeutic drugs

OBJECTIVE

The pathogenesis of idiopathic pulmonary fibrosis (IPF) remains unclear. We sought to identify IPF-related genes that may participate in the pathogenesis and predict potential targeted traditional Chinese medicines (TCMs).

METHODS

Using IPF gene-expression data, Wilcoxon rank-sum tests were performed to identify differentially expressed genes (DEGs). Protein-protein interaction (PPI) networks, hub genes, and competitive endogenous RNA (ceRNA) networks were constructed or identified by Cytoscape. Quantitative polymerase chain reaction (qPCR) experiments in TGF-β1-induced human fetal lung (HFL) fibroblast cells and a pulmonary fibrosis mouse model verified gene reliability. The SymMap database predicted potential TCMs targeting IPF. The reliability of TCMs was verified in TGF-β1-induced MRC-5 cells.

MATERIALS

Multiple gene-expression profile data of normal lung and IPF tissues were downloaded from the Gene Expression Omnibus database. HFL fibroblast cells and MRC-5 cells were purchased from Wuhan Procell Life Science and Technology Co., Ltd. (Wuhan, China). C57BL/12 mice were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China).

RESULTS

In datasets GSE134692 and GSE15197, DEGs were identified using Wilcoxon rank-sum tests (both p < 0.05). Among them, 1885 DEGs were commonly identified, and 87% (1640 genes) had identical dysregulation directions (binomial test, p < 1.00E-16). A PPI network with 1623 nodes and 8159 edges was constructed, and 18 hub genes were identified using the Analyze Network plugin in Cytoscape. Of 18 genes, CAV1, PECAM1, BMP4, VEGFA, FYN, SPP1, and COL1A1 were further validated in the GeneCards database and independent dataset GSE24206. ceRNA networks of VEGFA, SPP1, and COL1A1 were constructed. The genes were verified by qPCR in samples of TGF-β1-induced HFL fibroblast cells and pulmonary fibrosis mice. Finally, Sea Buckthorn and Gnaphalium Affine were predicted as potential TCMs for IPF. The TCMs were verified by qPCR in TGF-β1-induced MRC-5 cells.

CONCLUSION

This analysis strategy may be useful for elucidating novel mechanisms underlying IPF at the transcriptome level. The identified hub genes may play key roles in IPF pathogenesis and therapy.

Pulmonary hypertension associated with lung disease: new insights into pathomechanisms, diagnosis, and management

Patients with chronic lung diseases, particularly interstitial lung disease and chronic obstructive pulmonary disease, frequently develop pulmonary hypertension, which results in clinical deterioration, worsening of oxygen uptake, and an increased mortality risk. Pulmonary hypertension can develop and progress independently from the underlying lung disease. The pulmonary vasculopathy is distinct from that of other forms of pulmonary hypertension, with vascular ablation due to loss of small pulmonary vessels being a key feature. Long-term tobacco exposure might contribute to this type of pulmonary vascular remodelling. The distinct pathomechanisms together with the underlying lung disease might explain why treatment options for this condition remain scarce. Most drugs approved for pulmonary arterial hypertension have shown no or sometimes harmful effects in pulmonary hypertension associated with lung disease. An exception is inhaled treprostinil, which improves exercise capacity in patients with interstitial lung disease and pulmonary hypertension. There is a pressing need for safe, effective treatment options and for reliable, non-invasive diagnostic tools to detect and characterise pulmonary hypertension in patients with chronic lung disease.

ROS-responsive microneedles loaded with integrin avβ6-blocking antibodies for the treatment of pulmonary fibrosis

Pulmonary fibrosis (PF) is a fibrotic interstitial pneumonia with poor prognosis and limited treatment methods. Inhibition of integrin αVβ6 expression could prevent pulmonary fibrosis, however, a phase II clinical trial of αVβ6-blocking antibody treating PF stopped prematurely due to low bioavailability and toxic side effects of systematic administration. Here, we describe a micro-invasive percutaneous transthoracic and hydrogen peroxide-responsive microneedle composed of degradable gel for smart delivery of integrin αvβ6-blocking antibody which has the advantages of rapid response, excellent biocompatibility, protection of bioactivity, high tissue permeation and specific targeting to lesions. This microneedle could partially release integrin αvβ6-blocking antibodies when exposed to hydrogen peroxide generated during PF, thus reducing activation of the pro-fibrotic factor TGF-β1 from its latent precursor and showing excellent therapeutic efficacy for PF.

Nesfatin-1, a novel energy-regulating peptide, alleviates pulmonary fibrosis by blocking TGF-β1/Smad pathway in an AMPKα-dependent manner

Pulmonary fibrosis is a chronic progressive disease which steadily causes a critical public health concern. Nesfatin-1, a novel energy-regulating peptide discovered in 2006, could increase the level of AMPK phosphorylation. Previous studies have unveiled that Nesfatin-1 possessed many pharmacological effects including anti-inflammation, anti-oxidative stress, anti-fibrosis, and the regulation of lipid metabolism. Here, we investigated the impact of Nesfatin-1 on pulmonary fibrosis. Male C57BL/6J mice were intraperitoneally injected with Nesfatin-1 (10 μg·kg^-1·day^-1) for 21 days since mice were intratracheally administrated with bleomycin (BLM) (2 U/kg). Primary murine lung fibroblasts were stimulated with TGF-β1 (10 ng/ml) for 48 h. The results showed that Nesfatin-1 treatment significantly improved pulmonary function and decreased the production of collagen in BLM-treated mice. Meantime, Nesfatin-1 treatment also inhibited oxidative stress and inflammation in lung tissues from BLM-treated mice. Mechanically, Nesfatin-1 blocked the activation of TGF-β1/Smad2/3 signaling pathway in lung tissues challenged with BLM. In addition, we found that Nesfatin-1 enhanced the phosphorylation of AMPKα during pulmonary fibrosis. However, pharmacological inhibition or genetic deletion of AMPKα could both offset the pulmonary protection mediated by Nesfatin-1 during pulmonary fibrosis. Our experimental results firstly show Nesfatin-1 might serve as a novel treatment or adjuvant against pulmonary fibrosis by blocking TGF-β1/Smad pathway in an AMPKα-dependent manner.

Candida parapsilosis infection after double-lung transplantation in a patient with pulmonary fibrosis caused by COVID-19

Pulmonary fibrosis is a complication in patients with coronavirus disease 2019 (COVID-19). Extensive pulmonary fibrosis is a severe threat to patients' life and lung transplantation is last resort to prolong the life of patients. We reported a case of critical type COVID-19 patient, though various treatment measures were used, including anti-virus, anti-infection, improving immunity, convalescent plasma, prone position ventilation, and airway cleaning by fiber-optic bronchoscope, although his COVID-19 nucleic acid test turned negative, the patient still developed irreversible extensive pulmonary fibrosis, and respiratory mechanics suggested that lung compliance could not be effectively recovered. After being assisted by ventilator and extracorporeal membrane oxygenation for 73 days, he finally underwent double-lung transplantation. On the 2nd day after the operation, the alveolar lavage fluid of transplanted lung was examined by cytomorphology, and the morphology of alveolar epithelial cells was intact and normal. On the 20th day post-transplantation, the chest radiograph showed a large dense shadow in the middle of the right lung. On the 21st day, the patient underwent fiber-optic bronchoscopy, yeast-like fungal spores were found by cytomorphological examination from a brush smear of the right bronchus, which was confirmed as Candida parapsilosis infection by fungal culture. He recovered well due to the careful treatment and nursing in our hospital. Until July 29, 96 days after transplantation, the patient was recovery and discharged from hospital.

Indocyanine-enhanced mouse model of bleomycin-induced lung fibrosis with hallmarks of progressive emphysema

The development of new drugs for idiopathic pulmonary fibrosis strongly relies on preclinical experimentation, which requires the continuous improvement of animal models and integration with in vivo imaging data. Here, we investigated the lung distribution of bleomycin (BLM) associated with the indocyanine green (ICG) dye by fluorescence imaging. A long-lasting lung retention (up to 21 days) was observed upon oropharyngeal aspiration (OA) of either ICG or BLM + ICG, with significantly more severe pulmonary fibrosis, accompanied by the progressive appearance of emphysema-like features, uniquely associated with the latter combination. More severe and persistent lung fibrosis, together with a progressive air space enlargement uniquely associated with the BLM + ICG group, was confirmed by longitudinal micro-computed tomography (CT) and histological analyses. Multiple inflammation and fibrosis biomarkers were found to be increased in the bronchoalveolar lavage fluid of BLM- and BLM + ICG-treated animals, but with a clear trend toward a much stronger increase in the latter group. Similarly, in vitro assays performed on macrophage and epithelial cell lines revealed a significantly more marked cytotoxicity in the case of BLM + ICG-treated mice. Also unique to this group was the synergistic upregulation of apoptotic markers both in lung sections and cell lines. Although the exact mechanism underlying the more intense lung fibrosis phenotype with emphysema-like features induced by BLM + ICG remains to be elucidated, we believe that this combination treatment, whose overall effects more closely resemble the human disease, represents a valuable alternative model for studying fibrosis development and for the identification of new antifibrotic compounds.

Discovery of pulmonary fibrosis inhibitor targeting TGF-β RI in Polygonum cuspidatum by high resolution mass spectrometry with in silico strategy

Pulmonary fibrosis (PF) is an irreversible lung disease that is characterized by excessive scar tissue with a poor median survival rate of 2-3 years. The inhibition of transforming growth factor-β receptor type-I (TGF-β RI) by an appropriate drug may provide a promising strategy for the treatment of this disease. Polygonum cuspidatum (PC) is a well-known traditional Chinese herbal medicine which has an anti-PF effect. Accordingly, a combination of high resolution mass spectrometry with an in silico strategy was developed as a new method to search for potential chemical ingredients of PC that target the TGF-β RI. Based on this strategy, a total of 24 ingredients were identified. Then, absorption, distribution, metabolism, and excretion (ADME)-related properties were subsequently predicted to exclude compounds with potentially undesirable pharmacokinetics behaviour. Molecular docking studies on TGF-β RI were adopted to discover new PF inhibitors. Eventually, a compound that exists in PC known as resveratrol was proven to have excellent biological activity on TGF-β RI, with an IC₅₀ of 2.211 μM in vitro. Furthermore, the complex formed through molecular docking was tested via molecular dynamics simulations, which revealed that resveratrol had strong interactions with residues of TGF-β RI. This study revealed that resveratrol has significant potential as a treatment for PF due to its ability to target TGF-β RI. In addition, this research demonstrated the exploration of natural products with excellent biological activities toward specific targets via high resolution mass spectrometry in combination with in silico technology is a promising strategy for the discovery of novel drugs.

Prognostic analysis of m6A-related genes as potential biomarkers in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disease with limited treatment options. N6-methyladenosine (m6A) is a reversible RNA modification and has been implicated in various biological processes. However, there are few studies on m6A in IPF. This project mainly explores the prognostic value of m6A-related genes as potential biomarkers in IPF, in order to establish a set of accurate prognostic prediction model. In this study, we used GSE28042 dataset in GEO database to screen out 218 m6A-related candidate genes with high IPF correlation and high differential expression through differentially expressed gene analysis, WGCNA and m6A correlation analysis. The genes associated with the prognosis of IPF were screened out by univariate Cox regression analysis, LASSO analysis, and multivariate Cox regression analysis, and the multivariate Cox model of prognostic risk of related genes was constructed. We found that RBM11, RBM47, RIC3, TRAF5 and ZNF14 were key genes in our model. Finally, the prognostic prediction ability and independent prognostic characteristics of the risk model were evaluated by survival analysis and independent prognostic analysis, and verified by the GSE93606 dataset, which proved that the prognostic risk model we constructed has a strong and stable prediction efficiency.

A qualitative exploration of people living with idiopathic pulmonary fibrosis experience of a virtual pulmonary rehabilitation programme

Background

Pulmonary rehabilitation (PR) is recommended in the treatment of people with idiopathic pulmonary fibrosis (IPF). Little is known about the experiences of people with IPF of PR. Due to Covid-19 there has been a rapid shift of PR services to remote/virtual delivery.

Objective

To explore people living with IPFs experience of a virtual PR (VPR) programme.

Methods

All patients with a diagnosis of IPF in a stable phase of the disease were invited to participate in virtual PR: a 10 week exercise programme delivered twice-weekly for one hour. One-to-one semi- structured interviews were conducted within one week following the programme. All interviews were recorded, transcribed and analysed using Braun and Clarke thematic analysis by two independent assessors.

Results

N=13 participants took part in the semi-structured interviews, mean (standard deviation (SD)) age 69.5(10.4) years; 7M:6F. Mean (SD) FEV₁ 2.6(0.3)L, FVC 2.9(0.4)L. Four key themes were identified: 1) The impact of VPR on health and outlook, (2) The reality of VPR, (3) Being active after VPR and (4) Living with IPF during the COVID-19 Pandemic. Participants reported high levels of enjoyment and engagement with the programme regardless of the health benefits experienced. Most participants expressed a desire for a longer programme. Participants expressed different levels of maintenance with exercise since finishing the programme, specific motivators and strategies for maintenance included lung transplant, the maintenance of benefits from the programme and social support. COVID-19 and the restrictions imposed had some negative impacts on some participants lives, engaging with PR helped overcome some of these.

Conclusion

Despite the progressive nature of IPF, all participants expressed high levels of enjoyment with the programme. Future research should explore strategies for maintenance post PR and the optimum duration of PR for people with IPF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02221-6.

Tocotrienol-Rich Fractions Offer Potential to Suppress Pulmonary Fibrosis Progression

Although pulmonary fibrosis (PF) is considered a rare disease, the incidence thereof has increased steadily in recent years, while a safe and effective cure remains beyond reach. In this study, the potential of tocotrienol-rich fractions (TRF) and carotene to alleviate PF was explored. PF was induced in Sprague-Dawley rats via a single intratracheal bleomycin (BLM) (5 mg/kg) instillation. These rats were subsequently treated with TRF, carotene, pirfenidone (Pir) and nintedanib (Nin) for 28 days via gavage administration, whereafter histopathological performance, biochemical functions and molecular alterations were studied in the lung tissues. Our results showed that TRF, carotene, Nin and Pir all ameliorated PF by reducing inflammation and resisting oxidative stress to varying degrees. The related mechanisms involved the TGF-β1/Smad, PI3K/Akt and NF-κB signaling pathways. Ultimately, our findings revealed that, when combined with TRF, the therapeutic effects of Nin and Pir on PF were enhanced, indicating that TRF may, indeed, provide promising potential for use in combination therapy in the treatment of PF.

Plasticity towards Rigidity: A Macrophage Conundrum in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic, and ultimately fatal diffuse parenchymal lung disease. The molecular mechanisms of fibrosis in IPF patients are not fully understood and there is a lack of effective treatments. For decades, different types of drugs such as immunosuppressants and antioxidants have been tested, usually with unsuccessful results. Although two antifibrotic drugs (Nintedanib and Pirfenidone) are approved and used for the treatment of IPF, side effects are common, and they only slow down disease progression without improving patients’ survival. Macrophages are central to lung homeostasis, wound healing, and injury. Depending on the stimulus in the microenvironment, macrophages may contribute to fibrosis, but also, they may play a role in the amelioration of fibrosis. In this review, we explore the role of macrophages in IPF in relation to the fibrotic processes, epithelial–mesenchymal transition (EMT), and their crosstalk with resident and recruited cells and we emphasized the importance of macrophages in finding new treatments.

Mesenchyme Stem Cell-Derived Conditioned Medium as a Potential Therapeutic Tool in Idiopathic Pulmonary Fibrosis

Mesenchyme Stem Cells (MSCs) are the most used types of stem cells in regenerative medicine. Regenerative medicine is a rapidly emerging medicine section that creates new methods to regrow, restore, and replace diseased and damaged tissues, organs, and cells. Scholars have shown a positive correlation between MSCs-based therapies and successful treatment of diseases like cardiac ischemia, cartilage problems, bone diseases, diabetes, and even neurological disorders. Although MSCs have several varying features that make them unique, their immuno-regulatory effects in tissue repair emerge from their secretion of paracrine growth factors, exosomes, and cytokines. These cells secrete a secretome, which has regenerative and reparative properties that lead to injury amelioration, immune modulation, or fibrosis reduction. Recent studies have shown that the administration MCSs derived conditioned medium (MSCs-CM) in acute doses in humans is safe and well-tolerated. Studies from animal models and human clinical trials have also shown that they are efficacious tools in regenerative medicine. In this review, we will explore the therapeutic potential of MSCs-CM in pulmonary fibrosis, with further insight into the treatment of Idiopathic Pulmonary Fibrosis (IPF).

Inhibition of AHNAK nucleoprotein 2 alleviates pulmonary fibrosis by downregulating the TGF-β1/Smad3 signaling pathway

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic and advanced interstitial lung disease with poor prognosis. AHNAK nucleoprotein 2 (AHNAK2) is a macromolecular protein that is important for cell migration and muscle membrane repair. The protein acts via epithelial-mesenchymal transition (EMT), which is a key mechanism in the pathogenesis of IPF. However, very few studies have elucidated the effect of AHNAK2 in the development of IPF. Therefore, we aimed to determine the role of AHNAK2 in IPF development.

METHODS

C57BL/6 mice were induced with bleomycin (BLM), while A549 and Beas-2b pulmonary epithelial cell lines were treated with TGF-β1 to induce IPF model. The expression of AHNAK2 was detected using immunohistochemistry (IHC) staining in vivo, and real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB) in vitro. C57BL/6 mice were injected with adeno-associated virus (AAV)-sh NC or AAV-sh AHNAK2; the pulmonary function and EMT markers expression were measured in mice. The migratory abilities of the two transforming growth factor beta 1 (TGF-β1)-induced cell lines were examined using wound-healing and Transwell assays after transfection with si-NC, si-AHNAK2-1 and -2. EMT markers expression was detected using RT-qPCR and WB. Smad3 and phosphorylated-Smad3 of the two cells were examined using WB. Following Smad3 inhibition by Smad3 phosphorylation inhibitor (SIS3), TGF-β1-induced cell migration and EMT markers expression were evaluated again after different transfections.

RESULTS

AHNAK2 expression was higher in the IPF model than in the normal model in vivo and in vitro. Partial inhibition of AHNAK2 suppressed the EMT process and improved pulmonary ventilation and compliance in the mouse model of IPF. Similarly, knockdown of AHNAK2 suppressed the migration of pulmonary epithelial cells and reversed EMT. Furthermore, Smad3 of the two TGF-β1-induced cell lines was not activated when AHNAK2 was inhibited. When SIS3 inhibited the activation of Smad3, the suppression of AHNAK2 had no effect on A549 and Beas-2b, regardless of TGF-β1 induction.

CONCLUSIONS

Inhibition of AHNAK2 alleviates pulmonary fibrosis and partially reverses EMT by inhibiting the TGF-β1/Smad3 signaling pathway. Therefore, AHNAK2 is a potential therapeutic target for IPF.

Single Lung Transplant Remains a Viable Option for Patients With Severe Secondary Pulmonary Hypertension

BACKGROUND

Although double lung transplant is recommended in patients with severe secondary pulmonary hypertension (SPH), our institutional experiences suggest a role for single lung transplant in these patients. Here, we review our experience prioritizing single lung transplant in patients with SPH to minimize their surgical burden.

METHODS

We conducted a retrospective review of our lung transplant database to identify patients with SPH who underwent single lung transplant. Patients were stratified as either mild SPH (mean pulmonary artery pressure 25-40 mm Hg) or severe SPH (mean pulmonary artery pressure >40 mm Hg). Singe lung recipients without PH transplanted over the same time were also examined.

RESULTS

Between January 2017 and December 2019, 318 patients underwent single lung transplantation; 217 had mild SPH (68%), and 59 had severe SPH (18.5%). Forty-two patients without PH underwent single lung transplant. When the groups were compared, significantly higher pulmonary vascular resistance was noted in the severe SPH group, and obesity was noted in both the mild and severe SPH groups. Although the severe SPH group required more intraoperative cardiopulmonary support (37.3% versus 10.3% versus 4.7%, P < 0.05), there were no significant differences in most major postoperative parameters, including the duration of postoperative mechanical ventilation or the incidence of severe primary graft dysfunction. Survival 1 y posttransplant was not significantly different among the groups (93.2% versus 89.4% versus 92.9%, P = 0.58).

CONCLUSIONS

Our experience supports the option of single lung transplantation with appropriate intraoperative mechanical circulatory support in patients with SPH. This strategy is worth pursuing, especially with ongoing donor lung shortages.

Idiopathic pulmonary fibrosis: Current and future treatment

Objectives

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.

Data Source

The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.

Results

Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.

Conclusion

Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being.

Idiopathic Pulmonary Fibrosis: An Update on Pathogenesis

Idiopathic pulmonary fibrosis (IPF) is a progressive, lethal fibrotic lung disease that occurs primarily in middle-aged and elderly adults. It is a major cause of morbidity and mortality. With an increase in life expectancy, the economic burden of IPF is expected to continuously rise in the near future. Although the exact pathophysiological mechanisms underlying IPF remain not known. Significant progress has been made in our understanding of the pathogenesis of this devastating disease in last decade. The current paradigm assumes that IPF results from sustained or repetitive lung epithelial injury and subsequent activation of fibroblasts and myofibroblast differentiation. Persistent myofibroblast phenotype contributes to excessive deposition of the extracellular matrix (ECM) and aberrant lung repair, leading to tissue scar formation, distortion of the alveolar structure, and irreversible loss of lung function. Treatments of patients with IPF by pirfenidone and nintedanib have shown significant reduction of lung function decline and slowing of disease progression in patients with IPF. However, these drugs do not cure the disease. In this review, we discuss recent advances on the pathogenesis of IPF and highlight the development of novel therapeutic strategies against the disease.

Antifibrotic drugs in lung transplantation and chronic lung allograft dysfunction: a review

This review aims to provide an overview of pre-transplant antifibrotic therapy on peri-transplant outcomes and to address the possible role of antifibrotics in lung transplant recipients with chronic lung allograft dysfunction.Lung transplantation is an established treatment modality for patients with various end-stage lung diseases, of which idiopathic pulmonary fibrosis and other progressive fibrosing interstitial lung diseases are growing indications. Theoretically, widespread use of antifibrotics prior to lung transplantation may increase the risk of bronchial anastomotic complications and impaired wound healing.Long-term graft and patient survival are still hampered by development of chronic lung allograft dysfunction, on which antifibrotics may have a beneficial impact.Antifibrotics until the moment of lung transplantation proved to be safe, without increasing peri-transplant complications. Currently, best practice is to continue antifibrotics until time of transplantation. In a large multicentre randomised trial, pirfenidone did not appear to have a beneficial effect on lung function decline in established bronchiolitis obliterans syndrome. The results of antifibrotic therapy in restrictive allograft syndrome are eagerly awaited, but nonrandomised data from small case reports/series are promising.

Dehydrocostus lactone inhibits BLM-induced pulmonary fibrosis and inflammation in mice via the JNK and p38 MAPK-mediated NF-κB signaling pathways

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible inflammatory disease with a high mortality rate and limited therapeutic options. This study explored the potential role and mechanisms of Dehydrocostus lactone (DHL) in the inflammatory and fibrotic responses in a bleomycin (BLM) induced model. Treatment with DHL significantly reduced pathological injury and fibrosis, the secretion of BLM-induced pro-fibrotic mediators TGF-β and α-SMA, and components of the extracellular matrix (fibronectin). Additionally, in the early stages of inflammation, DHL administration inhibited the infiltration of inflammatory cells and downregulated the expression of TGF-β, TNF-α, and IL-6, indicating that DHL treatment effectively alleviated BLM-induced pulmonary fibrosis and inflammation in a dose-dependent manner. Furthermore, BLM induced the production of IL-33 in vivo, which initiated and progressed pulmonary fibrosis by activating macrophages and enhancing the production of IL-13 and TGF-β. In contrast, a significant decrease in the expression of IL-33 after DHL treatment in vitro showed that DHL strongly reduced IL-13 and TGF-β. Regarding the mechanism, BLM-induced phosphorylation of JNK, p38 MAPK, and NF-κB were significantly reduced after DHL treatment, which further led to the down-regulation of IL-33 expression, thereby decreasing IL-13 and TGF-β. Collectively, our data suggested that DHL could exert its anti-fibrosis effect via inhibiting the early inflammatory response by downregulating the JNK/p38 MAPK-mediated NF-κB signaling pathway to suppress macrophage activation. Therefore, DHL has therapeutic potential for pulmonary fibrosis.

Regulatory Immune Cells in Idiopathic Pulmonary Fibrosis: Friends or Foes?

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.

Inhibitory effects of alkaline extract from the pericarp of Citrus reticulata Blanco on collagen behavior in bleomycin-induced pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Peel of Citrus reticulata, a Chinese herbal drug with functions of regulating Qi and expelling phlegm, has been used for the treatment of lung related diseases in Chinese medicine for a long time. Its detailed effects on collagen in anti-idiopathic pulmonary fibrosis (IPF) is still unclear.

AIM OF THE STUDY

To explore the effects of citrus alkaline extract (CAE) on collagen synthesis, crosslinking and deposition in pulmonary fibrosis and understand the possible signal pathways involved in the activity.

MATERIALS AND METHODS

CAE was prepared from C. reticulata. Bleomycin-induced pulmonary fibrosis mouse model was applied. Pulmonary fibrosis of lung was estimated with histopathology analysis, and collagen deposition was evaluated with immunohistochemistry. Collagen crosslinking related biomarkers and enzymes were analyzed with chemical methods, immunohistochemical and western blot analyses.

RESULTS

CAE oral administration lowered hydroxyproline content, inhibited the collagen deposition including expressions of collagen I and III, and relieved bleomycin-induced pulmonary fibrosis in mice model. The productions of a collagen crosslink pyridinoline and crosslinking related enzymes including lysyl oxidase (LOX), lysyl oxidase-like protein 1 (LOXL1) in lung were suppressed by CAE treatment. Furthermore, the protein expressions of TGF-β1 and Smad3 levels in lungs were also downregulated by CAE.

CONCLUSIONS

This study demonstrated that CAE inhibited collagen synthesis, crosslinking and deposition, and ameliorated bleomycin-induced pulmonary fibrosis. Preliminary mechanism study revealed that CAE exerted its bioactivity at least via downregulation of TGF-β1/Smad3 pathway. Our findings provided a great potential in fighting IPF based on CAE.

Pulmonary hypertension in fibrosing idiopathic interstitial pneumonia: Uncertainties, challenges and opportunities

Pulmonary hypertension is a serious complication of chronic fibrosing idiopathic interstitial pneumonia (PH-fIIP) leading to greater morbidity and mortality. The pathophysiologic basis for PH in fIIP is not completely understood, but microvascular rarefaction may play a key role. Severe hypoxemia and reduced diffusion capacity are characteristic. Doppler echocardiography has limited diagnostic utility and right heart catheterization is required to confirm the diagnosis. Lung volumes can be minimally affected, and radiographic findings can be subtle, making the distinction from pulmonary arterial hypertension challenging. Several randomized controlled trials of pulmonary arterial hypertension targeted therapies have recently been completed. Endothelin-receptor antagonists have shown either no benefit or harm. Sildenafil may have some favorable short-term effects but does not appear to impact long-term outcomes. Riociguat treatment increased hospitalizations and mortality. A recent trial of inhaled treprostinil demonstrated improved exercise capacity, but the impact on long-term morbidity and mortality are unknown. Currently, the only viable option for improved survival is lung transplantation. Early referral is imperative to optimize post-transplant outcomes.

Proteomics in idiopathic pulmonary fibrosis: the quest for biomarkers

Idiopathic pulmonary fibrosis (IPF) is a debilitating chronic progressive and fibrosing lung disease that culminates in the destruction of alveolar integrity and dismal prognosis. Its etiology is unknown and pathophysiology remains unclear. While great advances have been made in elucidating the pathogenesis mechanism, considerable gaps related to information on pathogenetic pathways and key protein targets involved in the clinical course of the disease exist. These issues need to be addressed for better clinical management of this highly challenging disease. Omics approach has revolutionized the entire area of disease understanding and holds promise in its translation to clinical biomarker discovery. This review outlines the contribution of proteomics towards identification of important biomarkers in IPF in terms of their clinical utility, i.e. prognosis, differential diagnosis, disease progression and treatment monitoring. The major dysregulated pathways associated with IPF are also discussed. Based on numerous proteomics studies on human and animal models, it is proposed that IPF pathogenesis involves complex interactions of several pathways such as oxidative stress, endoplasmic reticulum stress, unfolded protein response, coagulation system, inflammation, abnormal wounding, fibroblast proliferation, fibrogenesis and deposition of extracellular matrix. These pathways and their key path-changing mediators need further validation in large well-planned multi-centric trials at various geographical locations for successful development of clinical biomarkers of this confounding disease.

S100A2 Silencing Relieves Epithelial-Mesenchymal Transition in Pulmonary Fibrosis by Inhibiting the Wnt/β-Catenin Signaling Pathway

Pulmonary fibrosis (PF) is a progressive and lethal disease with poor prognosis. S100A2 plays an important role in the progression of cancer. However, the role of S100A2 in PF has not yet been reported. In this study, we explored the potential role of S100A2 in PF and its potential molecular mechanisms. Increased expression of S100A2 was first observed in lung tissues of PF patients. We found that downregulation of S100A2 inhibited the transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in A549 cells. Mechanically, TGF-β1 upregulated β-catenin and the phosphorylation of glycogen synthase kinase-3β, which was blocked by silencing S100A2 in vitro. Furthermore, lithium chloride (activator of the Wnt/β-catenin signaling pathway) effectively rescued S100A2 knockdown-mediated inhibition of EMT in PF. In conclusion, these findings demonstrate that downregulation of S100A2 alleviated PF through inhibiting EMT. S100A2 is a promising potential target for further understanding the mechanism and developing a strategy for the treatment of PF and other EMT-associated diseases.

Investigation of telomere related gene mutations in idiopathic pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is the most common type of Idiopathic Interstitial Pneumonias (IIP). The aim of this study is to determine the mutation of variants in four telomere-related genes and to determine the possible relationship between these mutations and telomere shortening in order to contribute to the understanding of the pathophysiology of IPF. For this study, 34 individuals with IPF, 32 individuals with non-IPF ILD (Interstitial Lung Disease), and 31 healthy controls between the ages of 40 and 85 were included. The mutation analysis and telomere measurements were examined for the volunteers. According to the mutation screening results, no significant difference was found between the patients with IPF, non-IPF ILD groups and healthy individuals in terms of genotyping analysis. However, in terms of the allele distribution for two genes, statistically significant difference was found in IPF and non-IPF ILD patients (TERT; p = 0.002 and TERC; p = 0.001). According to the telomere length measurement, the telomeres of the patients were shorter than of the control group (p = 0.0001). In compliance with the results of our analysis, it is thought that genes that have allelic significance from the point of gene mutations as well as telomere shortening may be risk factors for the disease.

Idiopathic pulmonary fibrosis: Molecular mechanisms and potential treatment approaches

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease with high mortality that commonly occurs in middle-aged and older adults. IPF, characterized by a decline in lung function, often manifests as exertional dyspnea and cough. Symptoms result from a fibrotic process driven by alveolar epithelial cells that leads to increased migration, proliferation, and differentiation of lung fibroblasts. Ultimately, the differentiation of fibroblasts into myofibroblasts, which synthesize excessive amounts of extracellular matrix proteins, destroys the lung architecture. However, the factors that induce the fibrotic process are unclear. Diagnosis can be a difficult process; the gold standard for diagnosis is the multidisciplinary conference. Practical biomarkers are needed to improve diagnostic and prognostic accuracy. High-resolution computed tomography typically shows interstitial pneumonia with basal and peripheral honeycombing. Gas exchange and diffusion capacity are impaired. Treatments are limited, although the anti-fibrotic drugs pirfenidone and nintedanib can slow the progression of the disease. Lung transplantation is often contraindicated because of age and comorbidities, but it improves survival when successful. The incidence and prevalence of IPF has been increasing and there is an urgent need for improved therapies. This review covers the detailed cellular and molecular mechanisms underlying IPF progression as well as current treatments and cutting-edge research into new therapeutic targets.

Quantification of Lung Fibrosis in IPF-Like Mouse Model and Pharmacological Response to Treatment by Micro-Computed Tomography

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive degenerative lung disease leading to respiratory failure and death. Although anti-fibrotic drugs are now available for treating IPF, their clinical efficacy is limited and lung transplantation remains the only modality to prolong survival of IPF patients. Despite its limitations, the bleomycin (BLM) animal model remains the best characterized experimental tool for studying disease pathogenesis and assessing efficacy of novel potential drugs. In the present study, the effects of oropharyngeal (OA) and intratracheal (IT) administration of BLM were compared in C57BL/6 mice. The development of lung fibrosis was followed in vivo for 28 days after BLM administration by micro-computed tomography and ex vivo by histological analyses (bronchoalveolar lavage, histology in the left lung to stage fibrosis severity and hydroxyproline determination in the right lung). In a separate study, the antifibrotic effect of Nintedanib was investigated after oral administration (60 mg/kg for two weeks) in the OA BLM model. Lung fibrosis severity and duration after BLM OA and IT administration was comparable. However, a more homogeneous distribution of fibrotic lesions among lung lobes was apparent after OA administration. Quantification of fibrosis by micro-CT based on % of poorly aerated tissue revealed that this readout correlated significantly with the standard histological methods in the OA model. These findings were further confirmed in a second study in the OA model, evaluating Nintedanib anti-fibrotic effects. Indeed, compared to the BLM group, Nintedanib inhibited significantly the increase in % of poorly aerated areas (26%) and reduced ex vivo histological lesions and hydroxyproline levels by 49 and 41%, respectively. This study indicated that micro-computed tomography is a valuable in vivo technology for lung fibrosis quantification, which will be very helpful in the future to better evaluate new anti-fibrotic drug candidates.

Evasion of apoptosis by myofibroblasts: a hallmark of fibrotic diseases

Organ fibrosis is a lethal outcome of autoimmune rheumatic diseases such as systemic sclerosis. Myofibroblasts are scar-forming cells that are ultimately responsible for the excessive synthesis, deposition and remodelling of extracellular matrix proteins in fibrosis. Advances have been made in our understanding of the mechanisms that keep myofibroblasts in an activated state and control myofibroblast functions. However, the mechanisms that help myofibroblasts to persist in fibrotic tissues remain poorly understood. Myofibroblasts evade apoptosis by activating molecular mechanisms in response to pro-survival biomechanical and growth factor signals from the fibrotic microenvironment, which can ultimately lead to the acquisition of a senescent phenotype. Growing evidence suggests that myofibroblasts and senescent myofibroblasts, rather than being resistant to apoptosis, are actually primed for apoptosis owing to concomitant activation of cell death signalling pathways; these cells are poised to apoptose when survival pathways are inhibited. This knowledge of apoptotic priming has paved the way for new therapies that trigger apoptosis in myofibroblasts by blocking pro-survival mechanisms, target senescent myofibroblast for apoptosis or promote the reprogramming of myofibroblasts into scar-resolving cells. These novel strategies are not only poised to prevent progressive tissue scarring, but also have the potential to reverse established fibrosis and to regenerate chronically injured tissues.

Contemporary approaches in the use of extracorporeal membrane oxygenation to support patients waiting for lung transplantation

The introduction of the lung allocation score in 2005 prioritized patients with decreased transplant-free survival as the recipients of donor organs and effectively increased the number of critically-ill patients with end-stage lung disease waiting for transplantation. This change presented transplant programs with the challenge of how to both extend the lives of critically-ill, end-stage lung disease patients waiting for donor organs and maintain patient vitality to survival through the rigors of surgery and post-transplant recovery. Motivated by the dismal outcomes of patients maintained on mechanical ventilation pre-transplant, transplant centers increasingly deploy extracorporeal membrane oxygenation (ECMO) as a means of supporting patients with advanced disease as a bridge to successful lung transplantation. ECMO is an extracorporeal gas exchange device providing delivery of oxygen and removal of carbon dioxide from blood passed through the circuit. The specific cannulation strategy determines whether ECMO provides primarily respiratory or circulatory support. The cannulation approach is tailored to the specific physiological manifestations of the pre-lung transplant candidate's disease process. For patients with profound hypoxic respiratory failure, a cannulation strategy that captures a large fraction of the venous return is required to maintain adequate support whereas lower circuit flows are sufficient for patients with predominantly hypercapnic respiratory failure. Improving outcomes and increasing experience with ECMO is motivating transplant centers to initiate support before patients require mechanical ventilation. Awake cannulation is increasingly common and is used to avoid the complications associated with intubation in advanced lung failure. Determining criteria for initiation of support and identifying the optimal approach to support patients with right heart failure in need of circulatory support are avenues of active investigation. Use of ECMO and other forms of extracorporeal support are rapidly becoming a mainstay in the care of the pre-lung transplant patient with advanced disease.

miR-200 family members reduce senescence and restore idiopathic pulmonary fibrosis type II alveolar epithelial cell transdifferentiation

Rationale

Alveolar type II (ATII) cells act as adult stem cells contributing to alveolar type I (ATI) cell renewal and play a major role in idiopathic pulmonary fibrosis (IPF), as supported by familial cases harbouring mutations in genes specifically expressed by these cells. During IPF, ATII cells lose their regenerative potential and aberrantly express pathways contributing to epithelial–mesenchymal transition (EMT). The microRNA miR-200 family is downregulated in IPF, but its effect on human IPF ATII cells remains unproven. We wanted to 1) evaluate the characteristics and transdifferentiating ability of IPF ATII cells, and 2) test whether miR-200 family members can rescue the regenerative potential of fibrotic ATII cells.

Methods

ATII cells were isolated from control or IPF lungs and cultured in conditions promoting their transdifferentiation into ATI cells. Cells were either phenotypically monitored over time or transfected with miR-200 family members to evaluate the microRNA effect on the expression of transdifferentiation, senescence and EMT markers.

Results

IPF ATII cells show a senescent phenotype (p16 and p21), overexpression of EMT (ZEB1/2) and impaired expression of ATI cell markers (AQP5 and HOPX) after 6 days of culture in differentiating medium. Transfection with certain miR-200 family members (particularly miR-200b-3p and miR-200c-3p) reduced senescence marker expression and restored the ability to transdifferentiate into ATI cells.

Conclusions

We demonstrated that ATII cells from IPF patients express senescence and EMT markers, and display a reduced ability to transdifferentiate into ATI cells. Transfection with certain miR-200 family members rescues this phenotype, reducing senescence and restoring transdifferentiation marker expression.

Idiopathic pulmonary fibrosis alveolar epithelial type II cells show senescence and EMT features, but miR-200b and miR-200c can restore the ability of type II cells to transdifferentiate in vitro into type I alveolar epithelial cellshttp://bit.ly/359tlit

RhoA-Dependent HGF and c-Met Mediate Gas6-Induced Inhibition of Epithelial-Mesenchymal Transition, Migration, and Invasion of Lung Alveolar Epithelial Cells

Previously, we demonstrated that growth arrest-specific protein 6 (Gas6)/Axl or Mer signaling inhibited the transforming growth factor (TGF)-β1-induced epithelial–mesenchymal transition (EMT) in lung epithelial cells. Hepatocyte growth factor (HGF) has also been shown to inhibit TGF-β1-induced changes in EMT markers. Here, we examined whether Gas6 signaling can induce the production of HGF and c-Met in lung alveolar epithelial cells to mediate the inhibition of EMT and to inhibit the migration and invasion of epithelial cells. The inhibition of the RhoA/Rho kinase pathway, using either a RhoA-targeted small interfering RNA (siRNA) or the Rho kinase pharmacologic inhibitor Y27362, prevented the inhibition of TGF-β1-induced EMT in LA-4 cells and primary alveolar type II (AT II) epithelial cells. The c-Met antagonist PHA-665752 also blocked the anti-EMT effects associated with Gas6. Moreover, treatment with Y27362 or PHA-665752 prevented the Gas6-mediated inhibition of TGF-β1-induced migration and invasion. Our data provided evidence that the RhoA-dependent production of HGF and c-Met mediated the Gas6-induced inhibition of EMT, migration and invasion in lung alveolar epithelial cells. Thus, Gas6/Axl and Mer/RhoA signaling may be necessary for the maintenance of homeostasis in the alveolar epithelium, via HGF and c-Met.

Epithelial⁻Mesenchymal Transition in the Pathogenesis of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a serious disease of the lung, which leads to extensive parenchymal scarring and death from respiratory failure. The most accepted hypothesis for IPF pathogenesis relies on the inability of the alveolar epithelium to regenerate after injury. Alveolar epithelial cells become apoptotic and rare, fibroblasts/myofibroblasts accumulate and extracellular matrix (ECM) is deposited in response to the aberrant activation of several pathways that are physiologically implicated in alveologenesis and repair but also favor the creation of excessive fibrosis via different mechanisms, including epithelial⁻mesenchymal transition (EMT). EMT is a pathophysiological process in which epithelial cells lose part of their characteristics and markers, while gaining mesenchymal ones. A role for EMT in the pathogenesis of IPF has been widely hypothesized and indirectly demonstrated; however, precise definition of its mechanisms and relevance has been hindered by the lack of a reliable animal model and needs further studies. The overall available evidence conceptualizes EMT as an alternative cell and tissue normal regeneration, which could open the way to novel diagnostic and prognostic biomarkers, as well as to more effective treatment options.

Health-related quality of life and stress-related post-transplant trajectories of lung transplant recipients: a three-year follow-up of the Swiss Transplant Cohort Study

BACKGROUND Lung transplantation (LTx) provides a viable option for the survival of end-stage lung diseases. Besides survival as a clinical outcome measure, health-related quality of life (HRQoL) and psychological distress have become important outcomes in studies investigating the effectiveness of LTx in the short- and long-term. OBJECTIVE To assess and compare HRQoL trajectories of patients after LTx prior to and over a follow-up period of three years post-transplant, and to identify differences regarding distress, HRQoL and patient-related outcomes. METHODS In this longitudinal study, 27 lung transplant recipients were prospectively examined for psychological distress (Symptom Checklist short version-9; SCL-K-9), health-related quality of life (EuroQOL five dimensions questionnaire; EQ-5D), depression (HADS-Depression scale), and socio-demographic and medical outcomes at two weeks, three months, six months and three years following LTx. Additionally, potential outcome-related predictors for LTx-outcomes at three years post-transplant were assessed. Data were collected in accordance with guidelines set by the STROBE (strengthening the reporting of observational studies in epidemiology) statement. RESULTS Lung transplant recipients showed the most pronounced improvements in HRQoL and reduction in psychological distress between two weeks and three months post-transplant, with relative stable HRQoL and distress trajectories thereafter. The most important predictors of poor somatic health trajectories over time were the pre-transplant disease severity score and the pre-transplant HADS-Depression score. In addition, idiopathic pulmonary fibrosis (IPF) and pre-transplant extracorporeal membrane oxygenation (ECMO)-use predicted poorer survival, while cystic fibrosis was associated with better survival three years post-transplant. COMCLUSION Lung transplantation yields significant survival and HRQoL benefits, with its peak improvement at three months post-transplant. The majority of patients can preserve these health changes in the long-term. Patients with a worse HRQoL and higher psychological distress at six months post-transplant tended to have a poorer survival post-transplant. Other risk factors for poorer survival included IPF, pre-transplant ECMO-use, pre-transplant symptoms of depression, high pre-transplant disease severity and worse somatic disease severity trajectories. The majority of LTx-recipients were unable to work due to illness-related reasons.

Hydrogel-based delivery of Il-10 improves treatment of bleomycin-induced lung fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is a life-threatening progressive lung disorder with limited therapeutic options. While interleukin-10 (IL-10) is a potent anti-inflammatory and anti-fibrotic cytokine, its utility in treating lung fibrosis has been limited by its short half-life. We describe an innovative hydrogel-based approach to deliver recombinant IL-10 to the lung for the prevention and reversal of pulmonary fibrosis in a mouse model of bleomycin-induced lung injury. Our studies show that a hyaluronan and heparin-based hydrogel system locally delivers IL-10 by capitalizing on the ability of heparin to reversibly bind IL-10 without bleeding or other complications. This formulation is significantly more effective than soluble IL-10 for both preventing and reducing collagen deposition in the lung parenchyma after 7 days of intratracheal administration. The anti-fibrotic effect of IL-10 in this system is dependent on suppression of TGF-β driven collagen production by lung fibroblasts and myofibroblasts. We conclude that hydrogel-based delivery of IL-10 to the lung is a promising therapy for fibrotic lung disorders.

Lung Transplantation in Idiopathic Pulmonary Fibrosis

Despite the advances in recent years in the treatment of idiopathic pulmonary fibrosis (IPF), it continues to be a progressive disease with poor prognosis. In selected patients, lung transplantation may be a treatment option, with optimal results in survival and quality of life. Currently, pulmonary fibrosis is the main cause of lung transplantation. However, mortality on the waiting list of these patients is high, since many patients are referred to the transplant units with advanced disease. There is not a parameter that can predict the survival of a specific patient. Different variables are to be considered in order to decide the right time to send them to a transplant unit. It is also very difficult to decide when to include these patients on the waiting list. Every patient diagnosed with IPF, without contraindications for surgery, should be referred early to a transplant unit for assessment. A uni or bilateral transplantation will be decided based on the characteristics of the patient and the experience of each center. The post-transplant survival of recipients with IPF is lower than that observed in other diseases, such as cystic fibrosis or chronic obstructive pulmonary disease as a consequence of their older age and the frequent presence of associated comorbidity. Post-transplant follow-up must be tight in order to assure optimal level of immunosuppressive treatment, detect complications associated with it, and avoid graft rejection. The main cause of long-term mortality is late graft dysfunction as a consequence of chronic rejection. Other complications, such as infections and tumors, must be considered.