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Pulmonary hypertension (PH) is a heterogeneous disease with a poor prognosis. Accurate risk stratification is essential for guiding treatment decisions in pulmonary arterial hypertension (PAH). Although various risk models have been developed for PAH, their comparative prognostic potential requires further exploration. Additionally, the applicability of risk scores in PH groups beyond group 1 remains to be investigated.

Dual-specificity phosphatase 8 (DUSP8) plays an important role as a selective c-Jun N-terminal kinase (JNK) phosphatase in mitogen-activated protein kinase (MAPK) signaling. In this study, we found that DUSP8 is silenced by miR-147b in patients with lung adenocarcinoma (LUAD), which correlates with poor overall survival. Overexpression of DUSP8 resulted in a tumor-suppressive phenotype in vitro and in vivo experimental models, whereas silencing DUSP8 with a siRNA approach abrogated the tumor-suppressive properties. We found that miR-147b is a posttranscriptional regulator of DUSP8 that is highly expressed in patients with LUAD and is associated with lower survival. NanoString analysis revealed that the MAPK signaling pathway is mainly affected by overexpression of miR-147b, leading to increased proliferation and migration and decreased apoptosis in vitro. Moreover, induction of miR-147b promotes tumor progression in vitro and in vivo experimental models. Knockdown of miR-147b restored DUSP8, decreased tumor progression in vitro, and increased apoptosis via JNK phosphorylation. These results suggest that miR-147b plays a key role in regulating MAPK signaling in LUAD. The link between DUSP8 and miR-147b may provide novel approaches for the treatment of lung cancer.

Background: Alveolar hypoxia causes pulmonary hypertension and enhanced right ventricular afterload, which may impair exercise tolerance. The phosphodiesterase-5 inhibitor sildenafil has been reported to cause pulmonary vasodilatation. Objective: To investigate the effects of sildenafil on exercise capacity under conditions of hypoxic pulmonary hypertension. Design: Randomized, double-blind, placebo-controlled crossover study. Setting: University Hospital Giessen, Giessen, Germany, and the base camp on Mount Everest. Participants: 14 healthy mountaineers and trekkers. Measurements: Systolic pulmonary artery pressure, cardiac output, and peripheral arterial oxygen saturation at rest and during assessment of maximum exercise capacity on cycle ergometry 1) while breathing a hypoxic gas mixture with 10% fraction of inspired oxygen at low altitude (Giessen) and 2) at high altitude (the Mount Everest base camp). Intervention: Oral sildenafil, 50 mg, or placebo. Results: At low altitude, acute hypoxia reduced arterial oxygen saturation to 72.0% (95% CI, 66.5% to 77.5%) at rest and 60.8% (CI, 56.0% to 64.5%) at maximum exercise capacity. Systolic pulmonary artery pressure increased from 30.5 mm Hg (CI, 26.0 to 35.0 mm Hg) at rest to 42.9 mm Hg (CI, 35.6 to 53.5 mm Hg) during exercise in participants taking placebo. Sildenafil, 50 mg, significantly increased arterial oxygen saturation during exercise (P = 0.005) and reduced systolic pulmonary artery pressure at rest (P < 0.001) and during exercise (P = 0.031). Of note, sildenafil increased maximum workload (172.5 W [CI, 147.5 to 200.0 W]) vs. 130.6 W [CI, 108.8 to 150.0 W]); P < 0.001) and maximum cardiac output (P < 0.001) compared with placebo. At high altitude, sildenafil had no effect on arterial oxygen saturation at rest and during exercise compared with placebo. However, sildenafil reduced systolic pulmonary artery pressure at rest (P = 0.003) and during exercise (P = 0.021) and increased maximum workload (P = 0.002) and cardiac output (P = 0.015). At high altitude, sildenafil exacerbated existing headache in 2 participants. Limitations: The study did not examine the effects of sildenafil on normoxic exercise tolerance. Conclusions: Sildenafil reduces hypoxic pulmonary hypertension at rest and during exercise while maintaining gas exchange and systemic blood pressure. To the authors' knowledge, sildenafil is the first drug shown to increase exercise capacity during severe hypoxia both at sea level and at high altitude.

Nocturnal periodic breathing (PB) closely resembling Cheyne-Stokes respiration in congestive heart failure has been reported to occur in end-stage primary pulmonary hypertension (PPH). We herein describe the clinical course of [...]

Background: Inhalation of the stable prostacyclin analogue iloprost is being studied for treatment of pulmonary hypertension. The selective phosphodiesterase-5 inhibitor sildenafil has been reported to cause pulmonary vasodilatation. Objective: To evaluate the safety and effectiveness of oral sildenafil, alone and in combination with inhaled iloprost, for treatment of pulmonary hypertension. Design: Randomized, controlled, open-label trial. Patients: 30 patients with severe pulmonary arterial hypertension (n=16), chronic thromboembolic pulmonary hypertension (n=13), or pulmonary hypertension due to aplasia of the left pulmonary artery (n=1), all classified as New York Heart Association class III or IV. Intervention: All patients received inhaled nitric oxide and aerosolized iloprost (inhaled dose, 2.8 micrograms). They were then randomly assigned to receive 12.5 mg of oral sildenafil, 50 mg of sildenafil, 12.5 mg of sildenafil plus inhaled iloprost, or 50 mg of sildenafil plus inhaled iloprost. Measurements: Systemic and pulmonary arterial pressure, pulmonary arterial occlusion pressure, cardiac output, central venous pressure, peripheral arterial oxygen saturation, and arterial and mixed venous blood gases were measured during right-heart catheterization by using a Swan-Ganz catheter. Results: In rank order of pulmonary vasodilatory potency (maximum reduction of pulmonary vascular resistance and increase in cardiac index), 50 mg of sildenafil plus iloprost was most effective, followed by 12.5 mg of sildenafil plus iloprost. Iloprost alone and 50 mg of sildenafil were almost equally effective but were less potent than the combination regimens, and the least potent treatments were 12.5 mg of sildenafil and nitric oxide. In patients who received 50 mg of sildenafil plus iloprost, the maximum change in pulmonary vasodilatory potency was 44.2% (95% CI, -49.5% to 38.8%), compared with 14.1% (CI, -19.1% to 9.2%) in response to nitric oxide. With administration of 50 mg of sildenafil plus iloprost, the area under the curve for reduction in pulmonary vasodilatory effect lasted longer than 3 hours, and systemic arterial pressure and arterial oxygenation were maintained. No serious adverse events occurred. Conclusion: Although limited by the small sample and lack of long-term observations, the study shows that oral sildenafil is a potent pulmonary vasodilatory that acts synergistically with inhaled iloprost to cause strong pulmonary vasodilatation in both severe pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

Objective: To compare the effects of aerosolization of prostacyclin and its stable analog iloprost with those of nasal oxygen, inhaled nitric oxide, and intravenous prostacyclin on hemodynamics and gas exchange in patients with severe pulmonary hypertension. Design: Open uncontrolled trial. Setting: Justus-Liebig-University, Giessen, Germany. Patients: 4 patients with primary pulmonary hypertension and 2 patients with severe pulmonary hypertension associated with calcinosis, the Raynaud phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia (the CREST syndrome). All were classified as New York Heart Association class III or class IV. Intervention: Short-term applications of [O.sub.2], inhaled nitric oxide, intravenous prostacyclin, aerosolized prostacyclin, and aerosolized iloprost during repeated catheter investigation of the right side of the heart within a 1-month period. One patient had long-term therapy with inhaled iloprost. Results: Aerosolized prostacyclin decreased pulmonary artery pressure in 6 patients from (mean [+ or -] SE) 62.3 [+ or -] 4.1 mm Hg to 50.8 [+ or -] 5.5 mm Hg and reduced pulmonary vascular resistance from 1721 [+ or -] 253 dyne/s . [cm.sup.-5] to 1019 [+ or -] 203 dyne/s . [cm.sup.-5], and it increased cardiac output from 2.75 [+ or -] 0.21 L/min to 4.11 [+ or -] 0.54 L/min, mixed venous oxygen saturation from 51.1% [+ or -] 3.4% to 66.3% [+ or -] 4.1%, and arterial oxygen saturation from 90.6% [+ or -] 2.7% to 93.8% [+ or -] 23% (P < 0.05 for all changes). Mean systemic arterial pressure was only slightly affected. The responses lasted for 10 to 30 minutes after inhalation was terminated. Aerosolized iloprost had an identical efficacy profile but was associated with a longer duration of the pulmonary vasodilatory effect (60 min to 120 min). In comparison, intravenous prostacyclin reduced pulmonary vascular resistance with corresponding efficacy but produced a more pronounced decline in systemic artery pressure and no clinically significant decrease in pulmonary artery pressure. Nitric oxide and [O.sub.2] were less potent pulmonary vasodilators in these patients. In one patient, 1 year of therapy with aerosolized iloprost (100 [mu]g/d in six aerosol doses) resulted in sustained efficacy of the inhaled vasodilator regimen and clinical improvement. Conclusion: Aerosolization of prostacyclin or its stable analog iloprost causes selective pulmonary vasodilatation, increases cardiac output, and improves venous and arterial oxygenation in patients with severe pulmonary hypertension. Thus, it may offer a new strategy for treatment of this disease., Spraying prostacyclin or iloprost into the lungs of patients with primary pulmonary hypertension may help improve oxygenation and circulation through the lungs. In primary pulmonary hypertension, constriction of blood vessels in the lungs eventually leads to heart failure. Iloprost is a more chemically stable variety of prostacyclin, a drug that dilates blood vessels. Researchers evaluated the response to oxygen, inhaled nitric oxide, intravenous prostacyclin, prostacyclin spray, and iloprost spray in six patients with severe pulmonary hypertension. Oxygen improved blood oxygenation but did not improve circulation. Nitric oxide decreased blood vessel resistance in the lungs but only briefly. Prostacyclin and iloprost spray acted similarly to intravenous prostacyclin in that they decreased resistance to blood circulation through the lungs, but in addition, the sprays increased blood oxygenation. The effects of prostacyclin spray lasted 10 to 30 minutes while iloprost lasted one to two hours.

Abbreviations: BMPR2 = bone morphogenetic protein receptor type II; DHPLC = denaturing high performance liquid chromotography; LOD = logarithm of the odds for linkage; PASP = pulmonary artery systolic pressure; [...]

AbstractAim:This study assessed the utility of SPARC-like protein 1 (SPARCL1) as a biomarker of maladaptive right ventricular (RV) function in patients with pulmonary hypertension (PH).Methods:In this prospective study, we examined SPARCL1 levels in 105 patients with adaptive (n = 34) and maladaptive RV (n = 32) pressure overload caused by PH, dilated cardiomyopathy (DCM, n = 18) with LVEF < 35% and preserved RV function and controls without LV or RV abnormalities (n = 21).Results:The median SPARCL1 concentration in patients with maladaptive RV function was higher than in those with adaptive RV function (p < 0.01), DCM (p < 0.001) or controls (p < 0.001). Patients with adaptive RV function had higher SPARCL1 concentrations than controls (p < 0.05), whereas there was no difference between adaptive RV and DCM. SPARCL1 showed good predictive power for maladaptive RV (AUC 0.77, p < 0.001) with an optimal cut-off value of 9.66 ng/ml. The TAPSE/PASP ratio was the only independent predictor of SPARCL1 ≥ 9.66 ng/ml in multivariable logistic regression analysis.Conclusion:SPARCL1 shows potential as novel biomarker of RV pathological remodelling and is associated with RV maladaptation and ventriculoarterial uncoupling in PH.

Patients with COPD frequently demonstrate pulmonary hypertension (PH). Severe PH in patients with COPD, identified by pulmonary vascular resistance (PVR) of > 5 Wood units (WU), is closely linked to impaired transplant-free survival. The impact of PH-targeting pharmacotherapy in this context remains unclear.

Pulmonary arterial hypertension (PAH) is a rare, progressive vasculopathy with significant cardiopulmonary morbidity and mortality. Genetic testing is currently recommended for adults diagnosed with heritable, idiopathic, anorexigen-, hereditary hemorrhagic telangiectasia–, and congenital heart disease–associated PAH, PAH with overt features of venous/capillary involvement, and all children diagnosed with PAH. Variants in at least 27 genes have putative evidence for PAH causality. Rigorous assessment of the evidence is needed to inform genetic testing.

Although abnormal nuclear structure is an important criterion for cancer diagnostics, remarkably little is known about its relationship to tumor development. Here we report that loss of lamin B1, a determinant of nuclear architecture, plays a key role in lung cancer. We found that lamin B1 levels were reduced in lung cancer patients. Lamin B1 silencing in lung epithelial cells promoted epithelial–mesenchymal transition, cell migration, tumor growth, and metastasis. Mechanistically, we show that lamin B1 recruits the polycomb repressive complex 2 (PRC2) to alter the H3K27me3 landscape and repress genes involved in cell migration and signaling. In particular, epigenetic derepression of the RET proto-oncogene by loss of PRC2 recruitment, and activation of the RET/p38 signaling axis, play a crucial role in mediating the malignant phenotype upon lamin B1 disruption. Importantly, loss of a single lamin B1 allele induced spontaneous lung tumor formation and RET activation. Thus, lamin B1 acts as a tumor suppressor in lung cancer, linking aberrant nuclear structure and epigenetic patterning with malignancy.

In this study, we retrospectively assessed the relationships among physiologic measurements, survival, and quantitative high-resolution CT (HRCT) scanning indexes in patients with idiopathic pulmonary fibrosis (IPF).

Rare genetic variants cause pulmonary arterial hypertension, but the contribution of common genetic variation to disease risk and natural history is poorly characterised. We tested for genome-wide association for pulmonary arterial hypertension in large international cohorts and assessed the contribution of associated regions to outcomes.

(CHEST 2001; 120:4S-5S) Persistent alveolar fibrin formation may promote the development of lung fibrosis. To investigate this issue, pulmonary fibrosis was induced in New Zealand rabbits by aerosol application of [...]

Horst Olschewski, Dr(*); Beate Rohde, Dr; Juergen Behr, Dr; Ralf Ewert, Dr; Tobias Gessler, Dr; Hossein A Ghofrani, Dr; Almut Heuner, Dr; Thomas Schmehl, Dr and Werner Seeger, Prof Dr. [...]

Background: Inhaled aerosolized iloprost, a stable prostacyclin analogue, has been considered a selective pulmonary vasodilator in the management of pulmonary hypertension. Objective: To assess the efficacy of inhaled iloprost in the treatment of life-threatening pulmonary hypertension. Design: Open, uncontrolled, multicenter study. Setting: Intensive care units and pulmonary hypertension clinics at six university hospitals in Germany. Patients: 19 patients who had progressive right-heart failure despite receiving maximum conventional therapy (12 with primary pulmonary hypertension, 3 with pulmonary hypertension related to collagen vascular disease without lung fibrosis, and 4 with secondary pulmonary hypertension). Intervention: Inhaled iloprost, 6 to 12 times daily (50 to 200 [micro]g/d). Measurements: Right-heart catheterization and distance walked in 6 minutes at baseline and after 3 months of therapy. Results: During the first 3 months of therapy, New York Heart Association functional class improved in 8 patients and was unchanged in 7 patients. Four patients died, 3 of right-heart failure and 1 of sepsis. The acute hemodynamic response to inhaled iloprost was predominant pulmonary vasodilatation with little systemic effect at baseline and at 3 months (data available for 12 patients). Hemodynamic variables were improved at 3 months, and the distance walked in 6 minutes improved by 148 m (95% CI, 4.5 to 282 m; P = 0.048). Of the 15 patients who continued to use inhaled iloprost, 8 stopped: Four had lung transplantation, 1 switched to intravenous prostacyclin therapy, and 3 died. Seven patients are still receiving inhaled iloprost (mean [+ or -] SD) duration of therapy, 536 [+ or -] 309 days; mean dosage, 164 [+ or -] 38 [micro]g/d). Conclusions: Inhaled iloprost may offer a new therapeutic option for improvement of hemodynamics and physical function in patients with life-threatening pulmonary hypertension and progressive right-heart failure that is refractory to conventional therapy.

The majority of the eukaryotic genome is transcribed into noncoding RNAs (ncRNAs), which are important regulators of different nuclear processes by controlling chromatin structure. However, the full extent of ncRNA function has remained elusive. Here we deciphered the function of the microRNA Mirlet7das a key regulator of bidirectionally transcribed genes. We found that nuclear Mirlet7dbinds ncRNAs expressed from these genes. Mirlet7d–ncRNA duplexes are further bound by C1D, which in turn targets the RNA exosome complex and the polycomb repressive complex 2 (PRC2) to the bidirectionally active loci. The exosome degrades the ncRNAs, whereas PRC2 induces heterochromatin and transcriptional silencing through EZH2. Moreover, this multicomponent RNA–protein complex, which we named MiCEE, tethers the regulated genes to the perinucleolar region and thus is required for proper nucleolar organization. Our study demonstrates that the MiCEE complex mediates epigenetic silencing of bidirectionally expressed genes and global genome organization. The authors describe the MiCEE complex, which comprises Mirlet7dncRNA duplexes bound by C1D, the RNA exosome complex, and PRC2. MiCEE regulates bidirectionally transcribed loci and nucleolar organization.

The emergence of microRNA as regulators of organogenesis and tissue differentiation has stimulated interest in the ablation of microRNA expression and function during discrete periods of development. To this end, inducible, conditional modulation of microRNA expression with doxycycline-based tetracycline-controlled transactivator and tamoxifen-based estrogen receptor systems has found widespread use. However, the induction agents and components of genome recombination systems negatively impact pregnancy, parturition, and postnatal development; thereby limiting the use of these technologies between late gestation and the early postnatal period. MicroRNA inhibitor (antimiR) administration also represents a means of neutralizing microRNA function in vitro and in vivo. To date, these studies have used direct (parenteral) administration of antimiRs to experimental animals. As an extension of this approach, an alternative means of regulating microRNA expression and function is described here: the maternal–placental–fetal transmission of antimiRs. When administered to pregnant dams, antimiRs were detected in offspring and resulted in a pronounced and persistent reduction in detectable steady-state free microRNA levels in the heart, kidney, liver, lungs, and brain. This effect was comparable to direct injection of newborn mouse pups with antimiRs, although maternal delivery resulted in fewer off-target effects. Furthermore, depletion of steady-state microRNA levels via the maternal route resulted in concomitant increases in steady-state levels of selected microRNA targets. This novel methodology permits the temporal regulation of microRNA function during late gestation and in neonates, without recourse to conventional approaches that rely on doxycycline and tamoxifen, which may confound studies on developmental processes.

Fibrosis is associated with organ failure and high mortality and is commonly characterized by aberrant myofibroblast accumulation. Investigating the cellular origin of myofibroblasts in various diseases is thus a promising strategy for developing targeted anti-fibrotic treatments. Recent studies using genetic lineage tracing technology have implicated diverse organ-resident perivascular mesenchymal stem cell (MSC)-like cells and bone marrow-MSCs in myofibroblast generation during fibrosis development. In this Review, we give an overview of the emerging role of MSCs and MSC-like cells in myofibroblast-mediated fibrotic disease in the kidney, lung, heart, liver, skin, and bone marrow.

Background:Caffeine is widely used to manage apnea of prematurity, and reduces the incidence of bronchopulmonary dysplasia (BPD). Deregulated transforming growth factor (TGF)-β signaling underlies arrested postnatal lung maturation in BPD. It is unclear whether caffeine impacts TGF-β signaling or postnatal lung development in affected lungs.Methods:The impact of caffeine on TGF-β signaling in primary mouse lung fibroblasts and alveolar epithelial type II cells was assessed in vitro. The effects of caffeine administration (25 mg/kg/d for the first 14 d of postnatal life) on aberrant lung development and TGF-β signaling in vivo was assessed in a hyperoxia (85% O2)-based model of BPD in C57BL/6 mice.Results:Caffeine downregulated expression of type I and type III TGF-β receptors, and Smad2; and potentiated TGF-β signaling in vitro. In vivo, caffeine administration normalized body mass under hyperoxic conditions, and normalized Smad2 phosphorylation detected in lung homogenates; however, caffeine administration neither improved nor worsened lung structure in hyperoxia-exposed mice, in which postnatal lung maturation was blunted.Conclusion:Caffeine modulated TGF-β signaling in vitro and in vivo. Caffeine administration was well-tolerated by newborn mice, but did not influence the course of blunted postnatal lung maturation in a hyperoxia-based experimental mouse model of BPD.

Pathological alterations of inspiratory capacity (IC) have been observed in pulmonary hypertension. However, the clinical significance of IC in operable chronic thromboembolic pulmonary hypertension (CTEPH) without other pulmonary diseases remains unknown. CTEPH patients scheduled for pulmonary endarterectomy were prospectively screened. Despite being associated with functional capacity, pathological alterations of IC were not observed.

The BREELIB nebulizer was developed for iloprost to reduce inhalation times for patients with pulmonary arterial hypertension (PAH). This multicenter, randomized, unblinded, four-part study compared inhalation time, pharmacokinetics, and acute tolerability of iloprost 5 µg at mouthpiece delivered via BREELIB versus the standard I-Neb nebulizer in 27 patients with PAH. The primary safety outcome was the proportion of patients with a maximum increase in heart rate (HR) ≥ 25% and/or a maximum decrease in systolic blood pressure ≥ 20% within 30 min after inhalation. Other safety outcomes included systolic, diastolic, and mean blood pressure, HR, oxygen saturation, and adverse events (AEs). Median inhalation times were considerably shorter with BREELIB versus I-Neb (2.6 versus 10.9 min; n = 24). Maximum iloprost plasma concentration and systemic exposure (area under the plasma concentration–time curve) were 77% and 42% higher, respectively, with BREELIB versus I-Neb. Five patients experienced a maximum systolic blood pressure decrease ≥ 20%, four with BREELIB (one mildly and transiently symptomatic), and one with I-Neb; none required medical intervention. AEs reported during the study were consistent with the known safety profile of iloprost. The BREELIB nebulizer offers reduced inhalation time, good tolerability, and may improve iloprost aerosol therapy convenience and thus compliance for patients with PAH.

Progress in developing new therapies for bronchopulmonary dysplasia (BPD) is sometimes complicated by the lack of a standardised animal model. Our objective was to develop a robust hyperoxia-based mouse model of BPD that recapitulated the pathological perturbations to lung structure noted in infants with BPD. Newborn mouse pups were exposed to a varying fraction of oxygen in the inspired air (FiO2) and a varying window of hyperoxia exposure, after which lung structure was assessed by design-based stereology with systemic uniform random sampling. The efficacy of a candidate therapeutic intervention using parenteral nutrition was evaluated to demonstrate the utility of the standardised BPD model for drug discovery. An FiO2 of 0.85 for the first 14 days of life decreased total alveoli number and concomitantly increased alveolar septal wall thickness, which are two key histopathological characteristics of BPD. A reduction in FiO2 to 0.60 or 0.40 also caused a decrease in the total alveoli number, but the septal wall thickness was not impacted. Neither a decreasing oxygen gradient (from FiO2 0.85 to 0.21 over the first 14 days of life) nor an oscillation in FiO2 (between 0.85 and 0.40 on a 24 h:24 h cycle) had an appreciable impact on lung development. The risk of missing beneficial effects of therapeutic interventions at FiO2 0.85, using parenteral nutrition as an intervention in the model, was also noted, highlighting the utility of lower FiO2 in selected studies, and underscoring the need to tailor the model employed to the experimental intervention. Thus, a state-of-the-art BPD animal model that recapitulates the two histopathological hallmark perturbations to lung architecture associated with BPD is described. The model presented here, where injurious stimuli have been systematically evaluated, provides a most promising approach for the development of new strategies to drive postnatal lung maturation in affected infants.

Studies have suggested roles for angiopoietin-2 (Ang-2) and soluble P-selectin (sP-selectin) as biomarkers of disease severity and treatment response in pulmonary arterial hypertension (PAH), but additional data are required for validation. We evaluated these biomarkers using data from FREEDOM-C2, in which patients with PAH receiving stable monotherapy or combination therapy were randomized to receive additional treatment with oral treprostinil (up-titrated from 0.25 mg twice daily) or placebo for 16 weeks. Biomarker analysis was optional in FREEDOM-C2. We measured plasma Ang-2 and sP-selectin levels at baseline and at week 16, and we assessed their association with predefined outcomes (6-minute walk distance [6MWD] change from baseline >40 m, 6MWD >380 m, functional class I/II, and/or N-terminal pro-brain natriuretic peptide [NT-proBNP] <1,800 pg/mL at week 16) using Spearman correlation, receiver operating characteristics, and logistic regression. Biomarker data were available for 83 of 157 and 95 of 153 patients in the oral treprostinil and placebo groups, respectively. In the oral treprostinil group, baseline Ang-2 levels correlated with week 16 NT-proBNP levels (P< 0.0001). Baseline Ang-2 ≥12 ng/mL was associated with a reduced likelihood of having NT-proBNP <1,800 pg/mL at week 16 (multivariate odds ratio: 0.08; 95% confidence interval: 0.02–0.32). However, Ang-2 showed no significant association with the other assessed outcomes, and sP-selectin was not associated or correlated with any of the outcomes. These data suggest that Ang-2 and sP-selectin are not associated with response to oral treprostinil in patients already receiving stable PAH therapy. Trial registration: Clinicaltrials.gov identifier NCT00887978.

The right ventricle (RV) function plays a crucial role in the prognosis and functional outcome of PAH (Pulmonary Arterial Hypertension) patients. However, RV remodeling and its underlying mechanisms in PAH, and the molecular phenotype of RV in different disease conditions are poorly understood. Therefore, we designed this study to deeply investigate molecular changes underlying right ventricular remodeling and dysfunction in PAH. To this aim, we generated RNA-seq data from 40 patients' RV tissues, clinically classified in adaptive versus maladaptive RV hypertrophy. Using an unsupervised clustering-based analysis, we identified “early” and “late” subgroups in both diseased RV states, associated with patients’ hemodynamic profiles. We then demonstrated that the compensated RV is characterized by an upregulation of cell cycle-associated genes and mitochondrial respiration, whereas excessive levels of extracellular matrix components were central in the decompensation phase. However, dysregulation of fatty acid β-oxidation characterized the early decompensation phase. Furthermore, a comparative analysis from 30 RV samples of monocrotaline (MCT)-induced rat model largely confirmed the stage-specific molecular phenotypes, along with subgroups identification. Finally, we assessed the circulating levels of several dysregulated proteins in two independent cohorts of PAH patients and introduced a panel of five ECM-related proteins that had a significant alteration in patients with compensated vs. decompensated RV in both cohorts. Among those, NID1, C1QTNF1, and CRTAC1 demonstrated higher importance in predicting the development of maladaptive RV hypertrophy in both cohorts, while the correlation of their expression with cardiac functions confirmed their potential biomarker capacity in the prognosis of PAH-associated RV hypertrophy and failure. In conclusion, this comprehensive transcriptome study revealed new subgroups of human RV hypertrophy beyond the clinical measurements, while combination with proteome analysis proposed a panel of potential PAH biomarkers related to patients' RV function. Furthermore, our comparative analysis of two species supports the relevance of current animal models to explore new targets.

Inhalation of therapeutic aerosols has a long tradition and is, moreover, regarded as a safe and efficient route of drug administration to the respiratory tract. Especially, the targeting opportunities of this approach are beneficial for the treatment of numerous airway diseases. However, the rapid decay of local drug concentration and the resulting short-term duration of action of conventional medications necessitates several daily inhalations, which is clearly in conflict with a patients’ convenience and compliance. Recent progress in pharmaceutical engineering has provided promising drug delivery vehicles (e.g., liposomes, nanoparticles and thermo-responsive preparations) allowing for a sustained release of the encapsulated medication at the target site. Nevertheless, aspects such as generating tailored aerosols from these formulations (including stability during aerosolization) and the choice of biocompatible excipients remain considerable challenges, which need to be addressed in order to optimize inhalation therapy. Therefore, toxicology issues raised by these novel drug delivery vehicles with respect to physicochemical and material properties and biocompatibility are described in this review. This brief overview is intended to serve as a foundation to prompt future advancement in the field of controlled drug delivery to the lungs.

Vasoreactivity testing with inhaled NO is recommended for pulmonary arterial hypertension (PAH) because of its therapeutic and prognostic value. Sildenafil has acute pulmonary vasodilating properties, but its diagnostic and prognostic impact in PAH is unknown. Our objective was to compare acute vasodilating responses to sildenafil and those to NO during right heart catheterization and also their prognostic values in patients with PAH. Ninety-nine patients with idiopathic PAH and 99 with associated PAH underwent vasoreactivity testing with NO and sildenafil. Only mild adverse effects of sildenafil, in the form of hypotension, were observed, at a rate of 4.5%. The acute responder rate was 8.1% for NO and 11.6% for sildenafil. The NO-induced response in mean pulmonary arterial pressure and cardiac output correlated with the response to sildenafil. Thirteen patients were long-term responders to calcium channel blockers (CCBs), and 3 of them were correctly identified by acute vasoreactivity test with both drugs. The specificity of the vasoreactivity test for identifying long-term CCB responders was 88.9% for NO and 85.1% for sildenafil testing. A trend toward better survival was found in sildenafil and NO responders, compared with nonresponders. Use of sildenafil for vasoreactivity testing is safe. Sildenafil may be useful as alternative vasoreactivity-testing agent, identifying the same number of long-term CCB responders as NO. However, NO seems to be a more ideal testing drug because of its pharmacologic properties. Moreover, sildenafil vasoreactivity testing might contribute to an improved estimate of prognosis among patients with PAH.

Inhaled iloprost has proven to be an effective therapy in patients with pulmonary hypertension (PH). However, the acute hemodynamic effect of nebulized iloprost delivered via the I-neb Adaptive Aerosol Delivery (AAD) system remains unclear and needs to be assessed. In this study, 126 patients with PH were classified according to current guidelines (59, 34, 29, and 4 patients in groups 1/1′, 3, 4, and 5, respectively; 20 patients had idiopathic pulmonary arterial hypertension [iPAH]), were randomly assigned to inhale iloprost 2.5 g (n= 67) or 5.0 g (n= 59) via the I-neb AAD system, and were assessed by right heart catheterization. In seven patients with iPAH, iloprost plasma levels were measured. The two iloprost doses caused decreases from baseline in pulmonary vascular resistance (PVR; 2.5 g: –14.7%; 5.0 g: –15.6%) and mean pulmonary arterial pressure (mPAP; 2.5 g: –11.0%; 5.0 g: –10.1%) while cardiac index (CI) increased (2.5 g: +6.5%; 5.0 g: +6.4%). The subset with iPAH also showed decreases from baseline in PVR and mPAP and an increase in CI. Peak iloprost plasma levels showed no significant difference after inhalation of 2.5 g or 5.0 g iloprost (95.5 pg/mL vs. 73.0 pg/mL; P= 0.06). In summary, nebulized iloprost delivered via the I-neb AAD system reduced mPAP and PVR and increased CI from baseline in a heterogeneous group of patients with PH and in the subset with iPAH. In patients with iPAH, inhalation of 2.5 g or 5.0 g iloprost resulted in broadly similar peak iloprost plasma levels.

Phenotypic alterations in resident vascular cells contribute to the vascular remodeling process in diseases such as pulmonary (arterial) hypertension [P(A)H]. How the molecular interplay between transcriptional coactivators, transcription factors (TFs), and chromatin state alterations facilitate the maintenance of persistently activated cellular phenotypes that consequently aggravate vascular remodeling processes in PAH remains poorly explored. RNA sequencing (RNA-seq) in pulmonary artery fibroblasts (FBs) from adult human PAH and control lungs revealed 2460 differentially transcribed genes. Chromatin immunoprecipitation sequencing (ChIP-seq) revealed extensive differential distribution of transcriptionally accessible chromatin signatures, with 4152 active enhancers altered in PAH-FBs. Integrative analysis of RNA-seq and ChIP-seq data revealed that the transcriptional signatures for lung morphogenesis were epigenetically derepressed in PAH-FBs, including coexpression of T-box TF 4 (TBX4), TBX5, and SRY-box TF 9 (SOX9), which are involved in the early stages of lung development. These TFs were expressed in mouse fetuses and then repressed postnatally but were maintained in persistent PH of the newborn and reexpressed in adult PAH. Silencing of TBX4, TBX5, SOX9, or E1A-associated protein P300 (EP300) by RNA interference or small-molecule compounds regressed PAH phenotypes and mesenchymal signatures in arterial FBs and smooth muscle cells. Pharmacological inhibition of the P300/CREB-binding protein complex reduced the remodeling of distal pulmonary vessels, improved hemodynamics, and reversed established PAH in three rodent models in vivo, as well as reduced vascular remodeling in precision-cut tissue slices from human PAH lungs ex vivo. Epigenetic reactivation of TFs associated with lung development therefore underlies PAH pathogenesis, offering therapeutic opportunities.

Abstract Our previous findings demonstrated an increase in pulmonary mast cells (MCs) in idiopathic pulmonary arterial hypertension (IPAH). Also, literature suggests a potential role for MCs in chronic obstructive pulmonary disease (COPD). However, a comprehensive investigation of lungs from patients is still needed. We systematically investigated the presence/expression of MCs/MC chymase in the lungs of IPAH and COPD patients by (immuno)histochemistry and subsequent quantification. We found that total and perivascular chymase-positive MCs were significantly higher in IPAH patients than in donors. In addition, chymase-positive MCs were located in proximity to regions with prominent expression of big-endothelin-1 in the pulmonary vessels of IPAH patients. Total and perivascular MCs around resistant vessels were augmented and a significant majority of them were degranulated (activated) in COPD patients. While the total chymase-positive MC count tended to increase in COPD patients, the perivascular number was significantly enhanced in all vessel sizes analyzed. Surprisingly, MC and chymase-positive MC numbers positively correlated with better lung function in COPD. Our findings suggest that activated MCs, possibly by releasing chymase, may contribute to pulmonary vascular remodeling in IPAH. Pulmonary MCs/chymase may have compartment-specific (vascular vs. airway) functions in COPD. Future studies should elucidate the mechanisms of MC accumulation and the role of MC chymase in pathologies of these severe lung diseases.

To investigate whether NADPH oxidase 2 (NOX2), a major source of reactive oxygen species (ROS), contributes to the emergence of arterial hypertension in a murine model of sleep apnea.

Alveolar type-II cells (ATII cells) are lung progenitor cells responsible for regeneration of alveolar epithelium during homeostatic turnover and in response to injury. Characterization of ATII cells will have a profound impact on our understanding and treatment of lung disease. The identification of novel ATII cell-surface proteins can be used for sorting and enrichment of these cells for further characterization. Here we combined a high-resolution mass spectrometry-based membrane proteomic approach using lungs of the SILAC mice with an Affymetrix microarray-based transcriptome analysis of ATII cells. We identified 16 proteins that are enriched in the membrane fraction of ATII cells and whose genes are highly expressed in these cells. Interestingly, we confirmed our data for two of these genes, integrin beta 2 and 6 (Itgb2and Itgb6), by qRT-PCR expression analysis and Western blot analysis of protein extracts. Moreover, flow cytometry and immunohistochemistry in adult lung revealed that ITGB2 and ITGB6 are present in subpopulations of surfactant-associated-protein-C-positive cells, suggesting the existence of different types of ATII cells. Furthermore, analysis of the Itgb2–/–mice showed that Itgb2is required for proper WNT signaling regulation in the lung.

Abstract Hemodynamic measurements provide important parameters for determining prognosis and therapy in patients with pulmonary arterial hypertension (PAH). Current guidelines do not incorporate the possible predictive value of individual changes in hemodynamic variables during the disease time course, and there is no consensus about the time point for hemodynamic reevaluation. We aimed to assess the long-term prognostic value of short-term changes in hemodynamic parameters. The study included 122 patients with PAH from the Giessen Pulmonary Hypertension Registry who underwent hemodynamic evaluation at baseline and at 16 weeks (±2.5 standard deviations [SDs]; range: 4–29 weeks) after initial assessment. At baseline, mean pulmonary vascular resistance (PVR) was 1,109 dyn s cm−5, and 82% of patients were in World Health Organization (WHO) functional class III or IV. Fifty patients died, and 2 underwent lung transplantation during long-term observation (≤10 years; mean: 4.7 years). Kaplan-Meier estimates for transplant-free survival were 93.3%, 76.1%, 57.8%, and 53.1% at 1, 3, 5, and 7 years, respectively. When assigned to prognostic groups, improvements in cardiac output of >0.22 L min−1 (hazard ratio [HR]: 2.05; ) and a decrease in PVR of >176 dyn s cm−5 (HR: 1.89; ) at 4–29 weeks were associated with long-term transplant-free survival. Changes in mean pulmonary arterial pressure did not predict long-term prognosis. Of 2 noninvasive parameters assessed in this selected patient group, change in WHO functional class, but not in 6-minute walk distance, predicted long-term prognosis. Short-term assessment of changes in hemodynamic parameters at after initial invasive evaluation is useful to determine long-term prognosis in patients with PAH.

The imagination has made more discoveries than the eye To catch an imagination of the future of pulmonary hypertension was exactly the spirit of the 55th ASPEN lung Conference. Basic scientists, pre-clinicians, clinicians and pharma joined together to achieve one goal—to combine creativity and inventiveness in a battle against a deadly disease. Summarizing this conference on “Mechanics and Mechanisms of Pulmonary Hypertension” is challenging in several aspects: To extract key novel findings from 12 state-of-the-art lectures, 25 oral presentations, 56 posters along with the integration of own data on discussed topics, to include hundreds of important questions, answers and discussion raised during the conference, to provide the line of thinking for the next 5–10 years of pulmonary hypertension (PH) research development and to focus equally well on both basic and translational research. Kurt Stenmark and Todd Bull, who chaired the conference, intensified this challenge several-fold by selecting a plethora of topics ranging from development of cardiopulmonary systems to pathogenesis of right ventricular failure, mechanics of right ventricle-pulmonary artery coupling to genomics and from understanding metabolic aspects to developing therapies for PH. With that, need not say, but a special admiration and thanks to the conference chairs for assembling such outstanding state-of-the-art speakers, for clustering the presentations logically and for leading lively and engaging discussions. Although it may look fragmentary, we would like to divide the conference summary into four major conceptual realms: The pulmonary vasculature in PH; right heart in PH; individualized approach- personalized medicine; and beyond PH-vascular abnormalities in COPD. - Joseph Joubert

Pulmonary hypertension (PH) is a life-threatening disorder that is characterized by pulmonary arterial smooth muscle cell (PASMC) hyperplasia. Until now, little was been known about early changes that underlie the manifestation of PH. To characterize these early changes, we performed whole-genome microarray analysis of lungs from mice exposed to either 24 hours hypoxia or normoxia. TrkB, a member of the tyrosine kinase receptor family, and its ligand, brain-derived neurotrophic factor (BDNF), were strongly up-regulated in hypoxic mouse lungs, as well as in arteries of patients suffering from idiopathic pulmonary arterial hypertension (IPAH). BDNF stimulation of PASMC in vitroresulted in increased proliferation, TrkB and ERK1/2 phosphorylation, and nuclear translocation of the transcription factor early growth response factor 1 (Egr-1). In addition, increased Egr-1 expression was observed in idiopathic PAH lungs. The pro-proliferative effect of BDNF was attenuated by TrkB kinase inhibitor (K252a) or ERK1/2 inhibitor (U0126) pretreatment, and by knocking down Egr-1. Consequently, we have identified the BDNF-TrkB-ERK1/2 pathway as a proproliferative signaling pathway for PASMC in PH. Interference with this pathway may thus serve as an attractive reverse remodeling approach.

Pulmonary hypertension (PH) is a fatal disease characterized by remodeling processes such as increased migration and proliferation of pulmonary arterial smooth muscle cells (PASMC), enhanced matrix deposition, and dysregulation of cytoskeletal proteins. However, the contribution of cytoskeletal proteins in PH is still not fully understood. In this study, we have used a yeast two-hybrid screen to identify novel binding partners of the cytoskeletal adaptor protein four-and-a-half LIM domains 1 (Fhl-1). This identified paxillin as a new Fhl-1 interacting partner, and consequently we assessed its contribution to vascular remodeling processes. Native protein–protein binding was confirmed by co-immunoprecipitation studies in murine and human PASMC. Both proteins co-localized in PASMC in vitroand in vivo. In lung samples from idiopathic pulmonary arterial hypertension patients, paxillin expression was increased on mRNA and protein levels. Laser-microdissection of murine intrapulmonary arteries revealed elevated paxillin expression in hypoxia-induced PH. Furthermore, hypoxia-dependent upregulation of paxillin was HIF-1α dependent. Silencing of paxillin expression led to decreased PASMC adhesion, proliferation, and increased apoptosis. Regulation of these processes occurred via Akt and Erk1/2 kinases. In addition, adhesion of PASMC to the extracellular matrix protein fibronectin was critically dependent on paxillin expression. To summarize, we identified paxillin as a new regulator protein of PASMC growth.

Introduction:Lung cancer is the leading cause of cancer deaths worldwide. Although standard treatment regimens have produced promising results with neoadjuvant and adjuvant strategies, outcomes for patients with lung cancer are still considered disappointing. Recent data provide evidence that the tumor-stromal environment is a leading player in carcinogenesis, not just a supporting tumor compartment.Areas covered:This article reviews the current understanding of the lung cancer microenvironment and the complex bidirectional interplay between the tumor and lung microenvironment in non-small cell lung cancer (NSCLC). In particular, this review emphasizes the role of fibroblasts, mesenchymal stem cells and myeloid cells as well as mediators and molecular pathways regulated by these cells within the tumor microenvironment (TME) that contribute to lung tumor initiation, progression and metastasis. In addition, this review also summarizes the therapeutic strategies currently being applied in preclinical and clinical trials.Expert opinion:Considering the recent advances in understanding lung tumor stroma, lung cancer progression could be effectively hampered by combining cytotoxic strategies with therapies that target the TME. However, more preclinical and clinical research is needed to prove the efficacy of this strategy for treating NSCLC.

Our aim was to determine what proportion of patients with pulmonary hypertension (PH) has undertaken air travel contrary to the general medical advice and to characterize these patients according to disease severity and medical treatment. In cooperation with Pulmonale Hypertonie e.V., the German patient organization, a questionnaire was distributed. In total, 430 of 720 questionnaires were returned completed. Of the 179 patients who travelled at least once by air, the distribution of New York Heart Association functional classes I/ II/ III/ IV was 2/ 77/ 74/ 8, respectively; 83 patients were receiving monotherapy; 58 patients were receiving a combination of two or more therapies; 57 patients were on long-term ambulatory oxygen treatment; and 29 patients used supplemental oxygen while travelling. Overall, 20 adverse events were reported, mostly of mild to moderate severity (i.e., peripheral edema, dyspnea), with need of medical intervention in only 7 cases. The 251 patients who did not travel by air were, on average, in more advanced stages of disease and/or clinically unstable. In conclusion, a majority of patients (159 out of 179) did not experience any complications during or directly after the fight even though no special precautions were taken. Thus we conclude that for patients with PH in a stable clinical condition, air travel can be safe and well tolerated.

Platelet-derived growth factor (PDGF) has been implicated in the pathobiology of vascular remodeling. The multikinase inhibitor imatinib that targets PDGF receptor (PDGFR), c-kit and Abl kinases, shows therapeutic efficacy against experimental pulmonary hypertension (PH); however, the role of PDGFR-β in experimental PH has not been examined by genetic approach. We investigated the chronic hypoxia-induced PH in mice carrying an activating point mutation of PDGFR-β (D849N) and evaluated the therapeutic efficacy of imatinib. In addition, we studied pulmonary global gene expression and confirmed the expression of identified genes by immunohistochemistry. Chronically hypoxic D849N mice developed PH and strong pulmonary vascular remodeling that was improved by imatinib (100 mg/kg/day) as evident from the significantly reduced right ventricular systolic pressure, right ventricular hypertrophy and muscularization of peripheral pulmonary arteries. Global gene expression analysis revealed that stromal cell derived factor SDF)-1αwas significantly upregulated, which was confirmed by immunohistochemistry. Moreover, an enhanced immunoreactivity for SDF-1α, PDGFR-β and CXCR4, the receptor for SDF-1α was localized to the α-smooth muscle cell (SMC) actin positive pulmonary vascular cells in hypoxic mice and patients with idiopathic pulmonary arterial hypertension (IPAH). In conclusion, our findings substantiate the major role of PDGFR activation in pulmonary vascular remodeling by a genetic approach. Immunohistochemistry findings suggest a role for SDF-1α/CXCR4 axis in pulmonary vascular remodeling and point to a potential interaction between the chemokine SDF-1 and the growth factor PDGF signaling. Future studies designed to elucidate an interaction between the chemokine SDF-1 and the PDGF system may uncover novel therapeutic targets.

Acute lung injury (ALI) and sepsis are the major causes of mortality in intensive care units. Lymphocytes apoptosis is a hallmark feature of late detrimental sepsis. Parenteral nutrition in critically ill patients is based on lipid emulsions, but the impact of ALI and lipid emulsions on lymphocytes has not been defined. The effects of intravenously infused conventional soybean oil (SO)-based and new olive oil (OO)-based emulsions on splenic and blood lymphocytes were investigated in a murine model of endotoxin-induced ALI. After LPS challenge and infusion of lipid emulsions, apoptosis of lymphocytes and lung injury were assessed by flow cytometry, Western blot, and histology. Induction of ALI led to a time-dependent decline in splenic and circulating lymphocyte numbers and an increase in apoptosis, with engagement of the extrinsic apoptotic pathway. Both SO- and OO-based emulsions promoted the apoptosis of splenic lymphocytes before induction of ALI. The OO-based emulsions exhibited lower proapoptotic activity than did SO-based emulsions, an observation paralleled by the induction of survival factors. Induction of ALI increased the mortality of mice receiving SO-based emulsions compared with OO-based emulsions and normal saline. Splenic lymphocyte apoptosis is apparent in murine ALI, which may be linked to detrimental outcome. Infusion of lipid emulsions per seprovoked splenic lymphocyte apoptosis. Infusion of SO-based emulsions further augmented the apoptosis of splenic and circulating lymphocytes in ALI and led to increased mortality in mice. These findings may be of relevance for patients experiencing ALI that require parenteral nutrition.

Epithelial–mesenchymal transition (EMT) has emerged as a critical event in the pathogenesis of organ fibrosis and cancer and is typically induced by the multifunctional cytokine transforming growth factor (TGF)-β1. The present study was undertaken to evaluate the potential role of phosphodiesterases (PDEs) in TGF-β1-induced EMT in the human alveolar epithelial type II cell line A549. Stimulation of A549 with TGF-β1 induced EMT by morphological alterations and by expression changes of the epithelial phenotype markers E-cadherin, cytokeratin-18, zona occludens-1, and the mesenchymal phenotype markers, collagen I, fibronectin, and α-smooth muscle actin. Interestingly, TGF-β1 stimulation caused twofold increase in total cAMP-PDE activity, contributed mostly by PDE4. Furthermore, mRNA and protein expression demonstrated up-regulation of PDE4A and PDE4D isoforms in TGF-β1-stimulated cells. Most importantly, treatment of TGF-β1 stimulated epithelial cells with the PDE4-selective inhibitor rolipram or PDE4 small interfering RNA potently inhibited EMT changes in a Smad-independent manner by decreasing reactive oxygen species, p38, and extracellular signal-regulated kinase phosphorylation. In contrast, the ectopic overexpression of PDE4A and/or PDE4D resulted in a significant loss of epithelial marker E-cadherin but did not result in changes of mesenchymal markers. In addition, Rho kinase signaling activated by TGF-β1 during EMT demonstrated to be a positive regulator of PDE4. Collectively, the findings presented herein suggest that TGF-β1 mediated up-regulation of PDE4 promotes EMT in alveolar epithelial cells. Thus, targeting PDE4 isoforms may be a novel approach to attenuate EMT-associated lung diseases such as pulmonary fibrosis and lung cancer.

Studies to date have shown no survival benefit for the use of exogenous surfactant to treat patients with the ARDS. To identify specific patient subgroups for future study, we performed an exploratory post hocanalysis of clinical trials of recombinant surfactant protein-C (rSP-C) surfactant (Venticute; Nycomed GmbH; Konstanz, Germany).