Treprostinil Reconstitutes Mitochondrial Organisation and Structure in Idiopathic Pulmonary Fibrosis Cells.

Idiopathic pulmonary fibrosis (IPF) presents as an incurable change in the lung tissue and mitochondrial dysfunction of unknown origin. Treprostinil, a prostacyclin analogue, has been suggested for IPF therapy. This study assessed the effect of treprostinil on the cAMP signalling and mitochondrial activity in healthy lung fibroblasts and fibroblast-like cells from IPF patients. Six control fibroblast strains and six fibroblast-like IPF cell strains were isolated and expanded from freshly resected lung tissue. The cells were grown to confluence before being treated with either transforming growth factor (TGF)-ß1, treprostinil, their combination, or a vehicle for up to 2 days. Mitochondria-regulating proteins were analysed using Western blotting and immunofluorescence, and the mitochondria were analysed using cytochrome C, mitochondrial cytochrome C oxidase II (MTCO2), and MTCO4. The IPF cells showed an increased rate of damaged mitochondria, which were significantly reduced when the cells were treated with treprostinil over 24 h. In the control cells, treprostinil prevented TGF-ß-induced mitochondrial damage. Treatment with treprostinil modified the expression of several mitochondria-regulating proteins. In both cell types, treprostinil upregulated the expression of PTEN, p21(Waf1/Cip1), beclin1, LC3 II, parkin, PINK1, MTCO2, and MTCO4. In contrast, treprostinil downregulated the phosphorylation of mTOR and the expression of p62, mitofusin1, and mtiofusin2 in IPF cells. This might explain the reduced mitochondrial damage observed in treprostinil-treated IPF cells and suggest an improvement in the mitochondrial function in IPF. In this study, treprostinil improved mitochondrial impairment in vitro, which might, in part, explain the beneficial clinical effects documented in patients.

Clinical relevance of lung transplantation for COVID-19 ARDS: a nationwide study.

BACKGROUND: Although the number of lung transplantations (LTx) performed worldwide for COVID-19 induced acute respiratory distress syndrome (ARDS) is still low, there is general agreement that this treatment can save a subgroup of most severly ill patients with irreversible lung damage. However, the true proportion of patients eligible for LTx, the overall outcome and the impact of LTx to the pandemic are unknown. METHODS: A retrospective analysis was performed using a nationwide registry of hospitalised patients with confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-Cov-2) infection admitted between January 1, 2020 and May 30, 2021 in Austria. Patients referred to one of the two Austrian LTx centers were analyzed and grouped into patients accepted and rejected for LTx. Detailed outcome analysis was performed for all patients who received a LTx for post-COVID-19 ARDS and compared to patients who underwent LTx for other indications. RESULTS: Between January 1, 2020 and May 30, 2021, 39.485 patients were hospitalised for COVID-19 in Austria. 2323 required mechanical ventilation, 183 received extra-corporeal membrane oxygenation (ECMO) support. 106 patients with severe COVID-19 ARDS were referred for LTx. Of these, 19 (18%) underwent LTx. 30-day mortality after LTx was 0% for COVID-19 ARDS transplant recipients. With a median follow-up of 134 (47-450) days, 14/19 patients are alive. CONCLUSIONS: Early referral of ECMO patients to a LTx center is pivotal in order to select patients eligible for LTx. Transplantation offers excellent midterm outcomes and should be incorporated in the treatment algorithm of post-COVID-19 ARDS.

Multi-omics profiling predicts allograft function after lung transplantation.

RATIONALE: Lung transplantation is the ultimate treatment option for patients with end-stage respiratory diseases but bears the highest mortality rate among all solid organ transplantations due to chronic lung allograft dysfunction (CLAD). The mechanisms leading to CLAD remain elusive due to an insufficient understanding of the complex post-transplant adaptation processes. OBJECTIVES: To better understand these lung adaptation processes after transplantation and to investigate their association with future changes in allograft function. METHODS: We performed an exploratory cohort study of bronchoalveolar lavage samples from 78 lung recipients and donors. We analysed the alveolar microbiome using 16S rRNA sequencing, the cellular composition using flow cytometry, as well as metabolome and lipidome profiling. MEASUREMENTS AND MAIN RESULTS: We established distinct temporal dynamics for each of the analysed data sets. Comparing matched donor and recipient samples, we revealed that recipient-specific as well as environmental factors, rather than the donor microbiome, shape the long-term lung microbiome. We further discovered that the abundance of certain bacterial strains correlated with underlying lung diseases even after transplantation. A decline in forced expiratory volume during the first second (FEV1) is a major characteristic of lung allograft dysfunction in transplant recipients. By using a machine learning approach, we could accurately predict future changes in FEV1 from our multi-omics data, whereby microbial profiles showed a particularly high predictive power. CONCLUSION: Bronchoalveolar microbiome, cellular composition, metabolome and lipidome show specific temporal dynamics after lung transplantation. The lung microbiome can predict future changes in lung function with high precision.

IPF-Fibroblast Erk1/2 Activity Is Independent from microRNA Cluster 17-92 but Can Be Inhibited by Treprostinil through DUSP1.

Idiopathic pulmonary fibrosis (IPF) is a progressive terminal lung disease, and therapies aim to block fibrosis. Fibroblast proliferation is controlled by C/EBP-ß, microRNA cluster 17-92 (miR17-92), and Erk1/2 mitogen-activated protein kinase. This study assessed the role of miR17-92 in IPF-fibroblast proliferation and its modification by treprostinil. Fibroblasts were isolated from eight IPF patients, five interstitial lung fibrosis patients, and seven control lungs. Fibroblasts were stimulated with TGF-ß1 over 24 h. The miR17-92 expression was analyzed by RT-qPCR, and protein expression by Western blotting. TGF-ß1 upregulated C/EBP-ß in all fibroblasts, which was reduced by treprostinil in control-fibroblasts, but not in IPF-fibroblasts. Compared to controls, the guide strands miR-19a-3p, miR-19b-3p, miR-20a-5p, and miR-92a-3p, as well as the passenger strands miR-17-3p, miR-18-3p, miR-19a-1-5p, and miR-92a-5p were significantly increased in IPF-fibroblasts. In controls, TGF-ß1 and treprostinil significantly reduced specific miR17-92 members. IPF-fibroblast proliferation was inhibited by treprostinil through increased expression of the Erk1/2 inhibitor DUSP1. These data suggest that proliferation control via miR17-92 and C/EBP-ß is disrupted in IPF-fibroblasts. Therefore, the inhibition of early stages of signaling cascades or specific mitogen receptors might be less effective. However, the increased proliferation is sensitive to Erk1/2 inhibition by treprostinil-induced DUSP1.

Infraglottic versus supraglottic jet-ventilation for endobronchial ultrasound-guided transbronchial needle aspiration: A randomised controlled trial.

BACKGROUND: For endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) under general anaesthesia, both rigid bronchoscopy and laryngeal masks (LMAs) with superimposed high-frequency jet ventilation can be used. Despite the fact that in Europe rigid bronchoscopy for EBUS-TBNA is still widely used, an increasing number of centres use jet ventilation via the LMA for this procedure. To our knowledge no clinical trials have ever been made to compare these two methods. This trial aimed to evaluate whether patients recover from the procedure more quickly when a LMA is used for ventilation compared with rigid bronchoscopy where muscle relaxants and deep anaesthesia are required. OBJECTIVES: We wanted to test the hypothesis that there is no difference in the postoperative recovery of patients in the postanaesthesia care unit (PACU) after EBUS-TBNA with jet ventilation via a rigid bronchoscope and a LMA. Secondary outcomes were the difference of duration of anaesthesia, the diagnostic outcome of the procedure and drug quantities for both groups. DESIGN: Prospective randomised single blinded two centre controlled trial. SETTING: Two centres in Austria participated. Patients were enrolled from December 2016 until January 2018. PATIENTS: Ninety patients for elective EBUS-TBNA were enrolled and assigned to one of two intervention groups. Two patients were excluded before and eleven patients were excluded after EBUS-TBNA. Seventy-seven were analysed. INTERVENTIONS: Patients assigned to group 1 were ventilated with a LMA; those assigned to group 2 were ventilated via a rigid bronchoscope. Vital signs, drug dosage, duration of anaesthesia, recovery, PACU stay and Aldrete score at the PACU were recorded. MAIN OUTCOME MEASURES: The primary endpoint was an integral over time of a modified Aldrete score. Secondary endpoints were the durations of the interventions, the recovery from anaesthesia and PACU stay, initial and mean Aldrete values at PACU, the effect site concentration of Propofol according to the Schnider pharmacokinetic model, the peak ultiva rates and the diagnostic outcome. RESULTS: We were not able to show any significant difference regarding the postoperative recovery criteria based on the Aldrete score, the durations measured and the diagnostic outcomes. Vital signs remained stable and in an equal range in both groups. There were no differences in the mean effect site propofol concentration and the peak ultiva rates. CONCLUSION: EBUS-TBNA under general anaesthesia using a LMA with SHJV is equal to rigid bronchoscopy with superimposed high-frequency jet ventilation for the variables analysed. TRIAL REGISTRATION: ISRCTN (ISRCTN58911367).

Chest CT in patients after lung transplantation: A retrospective analysis to evaluate impact on image quality and radiation dose using spectral filtration tin-filtered imaging.

OBJECTIVES: The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation. METHODS: This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared. RESULTS: The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGy*cm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGy*cm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73). CONCLUSIONS: Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.

Combined Activation of Guanylate Cyclase and Cyclic AMP in Lung Fibroblasts as a Novel Therapeutic Concept for Lung Fibrosis.

Remodelling of the peripheral lung tissue and fibrotic foci are the main pathologies of idiopathic pulmonary fibrosis (IPF), a disease that is difficult to treat. TGF-ß activation of peripheral lung fibroblasts is indicated as the major cause of tissue remodelling in IPF and is resulting in fibroblast hyperplasia and deposition of extracellular matrix. Soluble guanylate cyclase (sGC) stimulators combined with cyclic AMP (cAMP) activators have been reported to reduce proliferation and matrix deposition in other conditions than IPF. Therefore, this drug combination may present a novel therapeutic concept for IPF. This study investigated the effect of BAY 41-2272 and forskolin on remodelling parameters in primary human lung fibroblasts. The study determined TGF-ß induced proliferation by direct cell counts after 3 days; and deposition of collagen type-I, type III, and fibronectin. BAY 41-2272 significantly reduced TGF-ß induced fibroblast proliferation, but did not reduce viability. This inhibitory effect was further supported by forskolin. Both BAY 41-2272 and forskolin alone reduced TGF-ß induced collagen and fibronectin de novo synthesis as well as deposition. This effect was significantly stronger when the two compounds were combined. Furthermore, the TGF-ß induced expression of fibrilar α-smooth muscle actin was reduced by BAY 41-2272 and this effect was strengthened by forskolin. In addition, BAY 41-2272 and forskolin reduced TGF-ß induced ß-catenin. All effects of BAY 41-2272 were concentration dependent. The findings suggest that BAY 41-2272 in combination with cAMP stimulation may present a novel therapeutic strategy to reduce tissue remodelling in IPF.

STING-dependent sensing of self-DNA drives silica-induced lung inflammation.

Silica particles induce lung inflammation and fibrosis. Here we show that stimulator of interferon genes (STING) is essential for silica-induced lung inflammation. In mice, silica induces lung cell death and self-dsDNA release in the bronchoalveolar space that activates STING pathway. Degradation of extracellular self-dsDNA by DNase I inhibits silica-induced STING activation and the downstream type I IFN response. Patients with silicosis have increased circulating dsDNA and CXCL10 in sputum, and patients with fibrotic interstitial lung disease display STING activation and CXCL10 in the lung. In vitro, while mitochondrial dsDNA is sensed by cGAS-STING in dendritic cells, in macrophages extracellular dsDNA activates STING independent of cGAS after silica exposure. These results reveal an essential function of STING-mediated self-dsDNA sensing after silica exposure, and identify DNase I as a potential therapy for silica-induced lung inflammation.

Mechanism of anti-remodelling action of treprostinil in human pulmonary arterial smooth muscle cells.

Treprostinil is applied for pulmonary arterial hypertension (PAH) therapy. However, the mechanism by which the drug achieves its beneficial effects in PAH vessels is not fully understood. This study investigated the effects of treprostinil on PDGF-BB induced remodelling parameters in isolated human pulmonary arterial smooth muscle cells (PASMC) of four PAH patients. The production of TGF-ß1, CTGF, collagen type-I and -IV, and of fibronectin were determined by ELISA and PCR. The role of cAMP was determined by ELISA and di-deoxyadenosine treatment. Proliferation was determined by direct cell count. Treprostinil increased cAMP levels dose and time dependently, which was not affected by PDGF-BB. Treprostinil significantly reduced PDGF-BB induced secretion of TGF-ß1 and CTGF, both was counteracted when cAMP generation was blocked. Similarly, the PDGF-BB induced proliferation of PASMC was dose dependently reduced by treprostinil through signalling via cAMP-C/EBP-α p42 -p21(WAf1/Cip1). In regards to extracellular matrix remodelling, treprostinil significantly reduced PDGF-BB-TGF-ß1-CTGF induced synthesis and deposition of collagen type I and fibronectin, in a cAMP sensitive manner. In contrast, the deposition of collagen IV was not affected. The data suggest that this action of treprostinil in vessel wall remodelling may benefit patients with PAH and may reduce arterial wall remodelling.

The attitudes of international medical students toward educational methods and styles applied in a 6-year longitudinal course in fundamentals of medical skills in Croatia.

AIM: To investigate international medical students' attitudes toward the impact of 6-year longitudinal course, Fundamentals of Medical Skills (FMS), at Medical Studies in English at the University of Zagreb on the development of their practical, clinical, and communication skills. METHODS: This cross-sectional study used a 23-item online survey to collect data from five generations of students attending the FMS course from January 31 to February 3, 2017. First-year students were not included. Invitations and reminders were sent to 202 FMS students by e-mail, SMS, and in closed groups in social networks Results. The response rate was 69.8% (141/202 students). The majority of students found the course useful (83.7%); favored practical over communication skills (92.9%); found practical skills more useful in higher years (82.3%); thought more time was needed to practice by simulation on mannequins (75.2%); preferred Objective Structured Clinical Examination (OSCE) stations to traditional oral exams (78%); and would recommend a course like FMS to future students or students at other universities (79.4%). Significantly more women than men favored practical over communication skills (P=0.044). Significantly more 5th and 6th students than students at lower years preferred OSCE stations to traditional learning (P=0.025) and would recommend a course like FMS to future students or students at other universities (P=0.001). CONCLUSION: Students positively evaluated the FMS course, but underestimated the communication skills aspect.

Torque Teno Virus as a Novel Biomarker Targeting the Efficacy of Immunosuppression After Lung Transplantation.

Torque teno viruses (TTV) are small DNA-viruses, of the genus Alphatorquevirus, whose replication is linked to immune status. TTV load may be an indicator for efficacy of IS in lung transplant recipients (LTRs). In a prospective single-center-study 143 LTRs were followed up and tested by quantitative TTV-DNA PCR. Using multivariate Cox-regression contribution of TTV-load to the occurrence of severe infections, chronic lung allograft dysfunction (CLAD), acute cellular rejection (ACR), and death was assessed. During follow-up 28 (20%) patients developed infections with a rate of 7.7 per 100 patient-years (PY). The hazard-ratio (HR) associated with a one-log10 increase of TTV-load before the event was 5.05. CLAD occurred with a rate of 6.0%-PY. HR for a 1 log10 increase of the lowest TTV level before the event was 0.71 (CI: 0.54-0.93). TTV-load predicts clinical events and may be useful to optimize IS during the first years of follow-up of LTRs.

Treprostinil inhibits proliferation and extracellular matrix deposition by fibroblasts through cAMP activation.

Idiopathic pulmonary fibrosis (IPF) is characterized by peripheral lung fibrosis and increased interstitial extracellular matrix (ECM) deposition. In IPF, tumor growth factor (TGF)-ß1 which is the major stimulus of ECM deposition, and platelet derived growth factor (PDGF)-BB is a potent stimulus of fibrosis. Thus, the effect of Treprostinil on TGF-ß1 and PDGF-induced fibroblast proliferation and ECM deposition was investigated. Human peripheral lung fibroblasts of seven IPF patients and five lung donors were stimulated by PDGF, or TGF-ß1, or the combination. Cells were pre-incubated (30 min) with either Treprostinil, forskolin, di-deoxyadenosine (DDA), or vehicle. Treprostinil time dependently activated cAMP thereby preventing PDGF-BB induced proliferation and TGF-ß1 secretion. Cell counts indicated proliferation; α-smooth muscle actin (α-SMA) indicted differentiation, and collagen type-1 or fibronectin deposition remodeling. Myo-fibroblast indicating α-SMA expression was significantly reduced and its formation was altered by Treprostinil. Collagen type-I and fibronectin deposition were also reduced by Treprostinil. The effect of Treprostinil on collagen type-I deposition was cAMP sensitive as it was counteracted by DDA, while the effect on fibronectin was not cAMP mediated. Treprostinil antagonized the pro-fibrotic effects of both PDGF-BB and TGF-ß1 in primary human lung fibroblasts. The data presented propose a therapeutic relevant anti-fibrotic effect of Treprostinil in IPF.

Lung transplantation in patients with incidental early stage lung cancer-institutional experience of a high volume center.

BACKGROUND: Incidentally discovered lung cancers in lung transplant (LuTX) recipients are rare but may affect outcome. We aim to report our single center experience with incidence, management, and survival of patients with previously unverified primary lung cancer discovered at the time of LuTX. METHODS: A total of 1262 patients undergoing LuTX between 1989 and 2012 were retrospectively analyzed in our prospective database. RESULTS: Patients identified were six men and five women with a mean age of 54.4±9.9 years. The indication for LuTX was COPD (n=9), pulmonary fibrosis (n=1), and cystic fibrosis (n=1). Histological diagnosis of the explanted lung revealed adenocarcinoma in six, squamous cell carcinoma in three, and lepidic predominant adenocarcinoma in two cases, respectively. Staging revealed stage IA (pT1a/b pN0) in eight and IB (pT2a pN0) in two cases and one patient in stage IIA (pT1b pN1). Subsequent cancer staging after LuTX revealed no metastasis. Immunosuppression was adjusted and no adjuvant chemo- or radiotherapy was administered. The 5-year survival rate was 90.5% with no detection of recurrence. CONCLUSION: In patients with incidentally detected early stage lung cancer at the time of LuTX, rates of recurrence and survival based on this sample appear to be acceptable.

A rare indication for lung transplantation - pulmonary alveolar microlithiasis: institutional experience of five consecutive cases.

BACKGROUND: Pulmonary alveolar microlithiasis (PAM) is a rare lung disease caused by calcifications within the alveolar space. The only known effective treatment for an end-stage PAM is lung transplantation (LuTX). METHODS: We performed a retrospective chart review of all individuals that underwent lung transplantation at our center between 1989 and 2013. Five consecutive patients with PAM were identified. RESULTS: Four females and one male with a mean age of 46.3 yr were identified. Extracorporeal membrane oxygenation (ECMO) support was required intraoperatively in four cases and post-operatively in one case. Mean post-operative intubation time was 3.3 (range, 2-5) d and mean intensive care unit (ICU) stay was 8.3 (range, 4-12) d. No intraoperative complications were observed. One early patient (operated in 1995) underwent acute re-transplantation on the second post-operative day (POD) and died from sepsis on the 11 POD. In one patient reperfusion edema was observed requiring a prolonged weaning process. No other severe perioperative complications were observed. Four of five patients are currently still alive with normal follow-up parameters. No recurrence of PAM was observed. CONCLUSIONS: Lung transplantation is a feasible therapy option in patients with end-stage PAM showing good post-operative results comparable to other indications for LuTX.

Aclidinium bromide combined with formoterol inhibits remodeling parameters in lung epithelial cells through cAMP.

Combined muscarinic receptor antagonists and long acting ß2-agonists improve symptom control in chronic obstructive pulmonary disease (COPD) significantly. In clinical studies aclidinium bromide achieved better beneficial effects than other bronchodilators; however, the underlying molecular mechanisms are unknown. This study assessed the effect of aclidinium bromide combined with formoterol on COPD lung (n=20) and non-COPD lung (n=10) derived epithelial cells stimulated with TGF-ß1+carbachol on: (i) the generation of mesenchymal cells in relation to epithelial cells, (II) extracellular matrix (ECM) deposition, and (iii) the interaction of ECM on the generation of epithelial and mesenchymal cells. TGF-ß1+carbachol enhanced the generation of mesenchymal cells, which was significantly reduced by aclidinium bromide or formoterol. The effect of combined drugs was additive. Inhibition of p38 MAP kinase and Smad by specific inhibitors or aclidinium bromide reduced the generation of mesenchymal cells. In mesenchymal cells, TGF-ß1+carbachol induced the deposition of collagen-I and fibronectin which was prevented by both drugs dose-dependently. Formoterol alone reduced collagen-I deposition via cAMP, this however, was overruled by TGF-ß1+carbachol and rescued by aclidinium bromide. Inhibition of fibronectin was cAMP independent, but involved p38 MAP kinase and Smad. Seeding epithelial cells on ECM collagen-I and fibronectin induced mesenchymal cell generation, which was reduced by aclidinium bromide and formoterol. Our results suggest that the beneficial effect of aclidinium bromide and formoterol involves cAMP affecting both, the accumulation of mesenchymal cells and ECM remodeling, which may explain the beneficial effect of the drugs on lung function in COPD.

Anti-fibrotic effects of nintedanib in lung fibroblasts derived from patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with poor prognosis. The kinase inhibitor nintedanib specific for vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and fibroblast growth factor receptor (FGFR) significantly reduced the rate of decline of forced vital capacity versus placebo. AIM: To determine the in vitro effect of nintedanib on primary human lung fibroblasts. METHODS: Fibroblasts were isolated from lungs of IPF patients and from non-fibrotic controls. We assessed the effect of VEGF, PDGF-BB and basic FGF (bFGF) ± nintedanib on: (i) expression/activation of VEGFR, PDGFR, and FGFR, (ii) cell proliferation, secretion of (iii) matrix metalloproteinases (MMP), (iv) tissue inhibitor of metalloproteinase (TIMP), and (v) collagen. RESULTS: IPF fibroblasts expressed higher levels of PDGFR and FGFR than controls. PDGF-BB, bFGF, and VEGF caused a pro-proliferative effect which was prevented by nintedanib. Nintedanib enhanced the expression of pro-MMP-2, and inhibited the expression of TIMP-2. Transforming growth factor-beta-induced secretion of collagens was inhibited by nintedanib. CONCLUSION: Our data demonstrate a significant anti-fibrotic effect of nintedanib in IPF fibroblasts. This effect consists of the drug's anti-proliferative capacity, and on its effect on the extracellular matrix, the degradation of which seems to be enhanced.

Extracellular matrix composition is modified by ß2-agonists through cAMP in COPD.

Long acting ß2-agonists (LABA) have been reported to modify the extracellular matrix (ECM) composition in the airway wall. Based on our earlier studies we here investigated the mechanism underlying the control of ECM modification by LABA in primary human airway smooth muscle cells. Cells were treated with formoterol or salmeterol (30 min) before TGF-ß1 stimulation (2-3 days) Using RT-PCT, immuno-blotting and ELISA the de novo synthesis and deposition of collagen type-I, -III, -IV and fibronectin were determined. Matrix metalloproteinases (MMP)-2 and -9 were analyzed by zymography. Both LABA activated cAMP and its corresponding transcription factor CREB within 60 min and thus partly reduced TGF-ß1-induced gene transcription of collagen type-I, -III, fibronectin and connective tissue growth factor (CTGF). The inhibitory effect of both LABA on collagen type-I and -III deposition involved a cAMP dependent mechanism, while the inhibitory effect of the two drugs on TGF-ß1-induced fibronectin deposition and on CTGF secretion was independent of cAMP. Interestingly, none of the two LABA reduced CTGF-induced synthesis of collagen type-I or type-III deposition. In addition, none of the two LABA modified collagen type-IV deposition or the expression and activity of MMP-2 or MMP-9. Our results show that LABA can prevent de novo deposition of specific ECM components through cAMP dependent and independent signaling. However, they do not reduce all ECM components by the same mechanism and they do not reduce existing collagen deposits. This might explain some of the controversial reports on the anti-remodeling effect of LABA in chronic inflammatory lung diseases.

The interaction of endothelin-1 and TGF-ß1 mediates vascular cell remodeling.

BACKGROUND: Pulmonary arterial hypertension is characterized by increased thickness of pulmonary vessel walls due to both increased proliferation of pulmonary arterial smooth muscle cell (PASMC) and deposition of extracellular matrix. In patients suffering from pulmonary arterial hypertension, endothelin-1 (ET-1) synthesis is up-regulated and may increase PASMC activity and vessel wall remodeling through transforming growth factor beta-1 (TGF-ß1) and connective tissue growth factor. OBJECTIVE: To assess the signaling pathway leading to ET-1 induced proliferation and extracellular matrix deposition by human PASMC. METHODS: PASMC were serum starved for 24 hours before stimulation with either ET-1 and/or TGF-ß1. ET-1 was inhibited by Bosentan, ERK1/2 mitogen activated protein kinase (MAPK) was inhibited by U0126 and p38 MAPK was inhibited by SB203580. RESULTS: ET-1 increased PASMC proliferation when combined with serum. This effect involved the mitogen activated protein kinases (MAPK) ERK1/2 MAPK and was abrogated by Bosentan which caused a G1- arrest through activation of p27((Kip)). Regarding the contribution of extracellular matrix deposition in vessel wall remodeling, TGF-ß1 increased the deposition of collagen type-I and fibronectin, which was further increased when ET-1 was added mainly through ERK1/2 MAPK. In contrast, collagen type-IV was not affected by ET-1. Bosentan dose-dependently reduced the stimulatory effect of ET-1 on collagen type-I and fibronectin, but had no effect on TGF-ß1. CONCLUSION AND CLINICAL RELEVANCE: ET-1 alone does not induce PASMC proliferation and extracellular matrix deposition. However, ET-1 significantly up-regulates serum induced proliferation and TGF-ß1 induced extracellular matrix deposition, specifically of collagen type-I and fibronectin. The synergistic effects of ET-1 on serum and TGF-ß1 involve ERK1/2 MAPK and may thus present a novel mode of action in the pathogenesis of pulmonary arterial hypertension.