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Background: MicroRNAs (miRNAs) are small noncoding RNAs that silence target gene expression posttranscriptionally, and their impact on gene expression has been reported in various diseases. It has been reported that the expression of the hypoxia-inducible factor-1α (HIF-1α) is reduced and that of p53 is increased in lungs from patients with COPD. However, the role of miRNAs associated with these genes in lungs from patients with COPD is unknown.Methods: Lung tissue samples from 55 patients were included in this study. Total RNA, miRNA, and protein were extracted from lung tissues and used for reverse transcriptase polymerase chain reaction and Western blot analysis. Cell culture experiments were performed using cultured human pulmonary microvascular endothelial cells (HPMVECs).Results: miR-34a and miR-199a-5p expressions were increased, and the phosphorylation of AKT was decreased in the lung tissue samples of patients with COPD. The miR-199a-5p expression was correlated with HIF-1α protein expression in the lungs of patients with COPD. Transfection of HPMVECs with the miR-199a-5p precursor gene decreased HIF-1α protein expression, and transfection with the miR-34a precursor gene increased miR-199a-5p expression.Conclusions: These data suggest that miR-34a and miR-199a-5p contribute to the pathogenesis of COPD, and these miRNAs may also affect the HIF-1α-dependent lung structure maintenance program. [ABSTRACT FROM AUTHOR]

Rationale: Inhibitors of histone deacetylases (HDACs) reduce pressure-overload-induced left ventricular hypertrophy and dysfunction, but their effects on right ventricular (RV) adaptation to pressure overload are unknown. Objectives: Determine the effect of the broad-spectrum HDAC inhibitors trichostatin A (TSA) and valproic acid (VPA) on RV function and remodeling after pulmonary artery banding (PAB) in rats. Methods: Chronic progressive RV pressure-overload was induced in rats by PAB. After establishment of adaptive RV hypertrophy 4 weeks after surgery, rats were treated for 2 weeks with vehicle, TSA, or VPA. RV function and remodeling were determined using echocardiography, invasive hemodynamic measurements, immunohistochemistry, and molecular analyses after 2 weeks of HDAC inhibition. The effects of TSA were determined on the expression of proangiogenic and prohypertrophic genes in human myocardial fibroblasts and microvascular endothelial cells. Measurements and Main Results: TSA treatment did not prevent the development of RV hypertrophy and was associated with RV dysfunction, capillary rarefaction, fibrosis, and increased rates of myocardial cell death. Similar results were obtained with the structurally unrelated HDAC inhibitor VPA. With TSA treatment, a reduction was found in expression of vascular endothelial growth factor and angiopoietin-1, which proteins are involved in vascular adaptation to pressure-overload. TSA dose-dependently suppressed vascular endothelial growth factor, endothelial nitric oxide synthase, and angiopoietin-1 expression in cultured myocardial endothelial cells, which effects were mimicked by selective gene silencing of several class I and II HDACs. Conclusions: HDAC inhibition is associated with dysfunction and worsened remodeling of the pressure-overloaded RV. The detrimental effects of HDAC inhibition on the pressure-overloaded RV may come about via antiangiogenic or proapoptotic effects. [ABSTRACT FROM AUTHOR]

Rationale: Impaired endothelial cell-dependent vasodilation, inflammation, apoptosis, and proliferation are manifestations of endothelial dysfunction in chronic obstructive pulmonary disease (COPD). Prostacyclin (PGI(2)) is a major product of the cyclooxygenase pathway with potent vasodilatory and antimitogenic properties and may be relevant to endothelial dysfunction in COPD.Objectives: To determine if PGI(2) expression is altered in smoking-related lung disease and if it may be protective in COPD-associated endothelial dysfunction.Methods: We evaluated, by immunohistochemistry, Western blotting, and polymerase chain reaction, human emphysema tissue compared with normal tissue for expression of prostacyclin synthase (PGI(2)S). We examined the effects of cigarette smoke extract (CSE) and aldehyde components on eicosanoid expression in primary human pulmonary microvascular endothelial cells. Finally, we used a murine model of lung-specific PGI(2)S overexpression and in vitro studies to determine if PGI(2) expression has protective effects on cigarette smoke-induced endothelial apoptosis.Measurements and Main Results: Human emphysema lung tissue exhibited lower PGI(2)S expression within the pulmonary endothelium than in normal lung. In vitro studies demonstrated that CSE, and in particular the alpha,beta unsaturated aldehyde acrolein, suppressed PGI(2)S gene expression, whereas CSE significantly induced the upstream mediators COX-2 and cytosolic phospholipase A2 in human pulmonary microvascular endothelial cells. Mice with lung-specific PGI(2)S overexpression exhibited less endothelial apoptosis after chronic smoke exposure. In vitro, iloprost exhibited protective effects on CSE-induced apoptosis.Conclusions: PGI(2) has protective effects in the pulmonary vasculature after acute and chronic cigarette smoke exposure. An imbalance in eicosanoid expression may be important to COPD-associated endothelial dysfunction. [ABSTRACT FROM AUTHOR]

Rationale: HIV-infected patients with pulmonary arterial hypertension have histologic manifestations that are indistinguishable from those found in patients with idiopathic pulmonary arterial hypertension. In addition, the role of pleiotropic viral proteins in the development of plexiform lesions in HIV-related pulmonary hypertension (HRPH) has not been explored. Simian immunodeficiency virus (SIV) infection of macaques has been found to closely recapitulate many of the characteristic features of HIV infection, and thus hallmarks of pulmonary arterial hypertension should also be found in this nonhuman primate model of HIV.Objectives: To determine whether pulmonary arterial lesions were present in archived SIV-infected macaque lung tissues from Johns Hopkins University and two National Primate Research Centers.Methods: Archived macaque and human lung sections were examined via immunohistochemistry for evidence of complex vascular lesions.Results: Complex plexiform-like lesions characterized by lumenal obliteration, intimal disruption, medial hypertrophy, thrombosis, and recanalized lumena were found exclusively in animals infected with SHIV-nef (a chimeric viral construct containing the HIV nef gene in an SIV backbone), but not in animals infected with SIV. The mass of cells in the lesions were factor VIII positive, and contained cells positive for muscle-specific and smooth muscle actins. Lung mononuclear cells were positive for HIV Nef, suggesting viral replication. Endothelial cells in both the SHIV-nef macaques and patients with HRPH, but not in patients with idiopathic pulmonary arterial hypertension, were also Nef positive.Conclusions: The discovery of complex vascular lesions in SHIV-nef- but not SIV-infected animals, and the presence of Nef in the vascular cells of patients with HRPH, suggest that Nef plays a key role in the development of severe pulmonary arterial disease. [ABSTRACT FROM AUTHOR]

Rationale: There is growing evidence that alveolar cell apoptosis plays an important role in emphysema pathogenesis, a chronic inflammatory lung disease characterized by alveolar destruction. The association of alpha1-antitrypsin deficiency with the development of emphysema has supported the concept that protease/antiprotease imbalance mediates cigarette smoke-induced emphysema.Objectives: We propose that, in addition to its antielastolytic effects, alpha1-antitrypsin may have broader biological effects in the lung, preventing emphysema through inhibition of alveolar cells apoptosis. METHODS, MEASUREMENTS, AND MAIN RESULTS: Transduction of human alpha1-antitrypsin via replication-deficient adeno-associated virus attenuated airspace enlargement and emphysema caused by inhibition of vascular endothelial growth factor (VEGF) receptors with SU5416 in mice, a model of apoptosis-dependent emphysema lacking neutrophilic inflammation. The overexpressed human serine protease inhibitor accumulated in lung cells and suppressed caspase-3 activation and oxidative stress in lungs treated with the VEGF blocker or with VEGF receptor-1 and -2 antibodies. Similar results were obtained in SU5416-treated rats given human alpha1-antitrypsin intravenously.Conclusions: Our findings suggest that inhibition of structural alveolar cell apoptosis by alpha1-antitrypsin represents a novel protective mechanism of the serpin against emphysema. Further elucidation of this mechanism may extend the therapeutic options for emphysema caused by reduced level or loss of function of alpha1-antitrypsin. [ABSTRACT FROM AUTHOR]

Rationale: Within the lungs of patients with severe emphysema, inflammation continues despite smoking cessation. Foci of T lymphocytes in the small airways of patients with emphysema have been associated with disease severity. Whether these T cells play an important role in this continued inflammatory response is unknown.Objective: The aim of this study was to determine if T cells recruited to the lungs of subjects with severe emphysema contain oligoclonal T-cell populations, suggesting their accumulation in response to antigenic stimuli.Methods: Lung T-cell receptor (TCR) Vbeta repertoire from eight patients with severe emphysema and six control subjects was evaluated at the time of tissue procurement (ex vivo) and after 2 weeks of culture with interleukin 2 (in vitro). Junctional region nucleotide sequencing of expanded TCR-Vbeta subsets was performed.Results: No significantly expanded TCR-Vbeta subsets were identified in ex vivo samples. However, T cells grew from all emphysema (n = 8) but from only one of the control lung samples (n = 6) when exposed to interleukin 2 (p = 0.0013). Within the cultured cells, seven major CD4-expressing TCR-Vbeta subset expansions were identified from five of the patients with emphysema. These expansions were composed of oligoclonal populations of T cells that had already been expanded in vivo.Conclusion: Severe emphysema is associated with inflammation involving T lymphocytes that are composed of oligoclonal CD4+ T cells. These T cells are accumulating in the lung secondary to conventional antigenic stimulation and are likely involved in the persistent pulmonary inflammation characteristic of severe emphysema. [ABSTRACT FROM AUTHOR]

The importance of genetic predisposition, inflammation, and autoimmune mechanisms in the development of pulmonary arterial hypertension (PAH) is becoming increasingly clear. We hypothesized that the analysis of gene expression profiles from peripheral blood mononuclear cells would distinguish patients with PAH from normal volunteers. We also hypothesized that a subset of genes would discriminate between patients with idiopathic PAH and pulmonary hypertension related to secondary causes. Mononuclear cells were isolated from 15 patients diagnosed with PAH and 6 normal control subjects. Microarray expression was performed, and the expression profiles were analyzed for consistent and predictive differences in gene expression. We identified a signature set of 106 genes that discriminated with high certainty (p < or = 0.002) between patients with PAH and normal individuals. The results of the microarray analysis were retrospectively and prospectively confirmed by quantitative polymerase chain reaction for 2 of the 106 genes. Supervised clustering analysis generated a list of differentially expressed genes between patients with idiopathic and secondary causes of pulmonary hypertension. Microarray expression profiling of peripheral blood cells can discriminate between patients with PAH and normal volunteers. These findings may have important implications toward diagnosis, screening, and pathogenesis of this disease. [ABSTRACT FROM AUTHOR]

Background: Hypoxia induces the proliferation of lung fibroblasts in vivo and in vitro. However, the subcellular interactions between hypoxia and expression of tumor suppressor p53 and cyclin-dependent kinase inhibitors p21 and p27 remain unclear.Methods: Normal human lung fibroblasts (NHLF) were cultured in a hypoxic chamber or exposed to desferroxamine (DFX). DNA synthesis was measured using bromodeoxyuridine incorporation, and expression of p53, p21 and p27 was measured using real-time RT-PCR and Western blot analysis.Results: DNA synthesis was increased by moderate hypoxia (2% oxygen) but was decreased by severe hypoxia (0.1% oxygen) and DFX. Moderate hypoxia decreased p21 synthesis without affecting p53 synthesis, whereas severe hypoxia and DFX increased synthesis of both p21 and p53. p27 protein expression was decreased by severe hypoxia and DFX. Gene silencing of p21 and p27 promoted DNA synthesis at ambient oxygen concentrations. p21 and p53 gene silencing lessened the decrease in DNA synthesis due to severe hypoxia or DFX exposure. p21 gene silencing prevented increased DNA synthesis in moderate hypoxia. p27 protein expression was significantly increased by p53 gene silencing, and was decreased by wild-type p53 gene transfection.Conclusion: These results indicate that in NHLF, severe hypoxia leads to cell cycle arrest via the p53-p21 pathway, but that moderate hypoxia enhances cell proliferation via the p21 pathway in a p53-independent manner. In addition, our results suggest that p27 may be involved in compensating for p53 in cultured NHLF proliferation. [ABSTRACT FROM AUTHOR]

Severe pulmonary arterial hypertension, whether idiopathic or secondary, is characterized by structural alterations of microscopically small pulmonary arterioles. The vascular lesions in this group of pulmonary hypertensive diseases show actively proliferating endothelial cells without evidence of apoptosis. In this article, we review pathogenetic concepts of severe pulmonary arterial hypertension and explain the term "complex vascular lesion ", commonly named "plexiform lesion", with endothelial cell dysfunction, i.e., apoptosis, proliferation, interaction with smooth muscle cells and transdifferentiation. [ABSTRACT FROM AUTHOR]

Pulmonary fibrosis (PF) can be a fatal disease characterized by progressive lung scarring. It is still poorly understood how the pulmonary endothelium is involved in the disease pathogenesis. Differences of the pulmonary vasculature between patients and donors were analyzed using transmission electron microscopy, immunohistochemistry, and single-cell RNA sequencing. Vascular barrier resistance, endothelial-immune cell adhesion, and sensitivity to an inflammatory milieu were studied in vitro . Integrity and activation markers were measured by ELISA in human plasma. Transmission electron microscopy demonstrated abnormally swollen endothelial cells (ECs) in fibrotic lungs compared with donors. A more intense CD31 and von Willebrand Factor (vWF) and patchy vascular endothelial (VE)-Cadherin staining in fibrotic lungs supported the presence of a dysregulated endothelium. Integrity markers CD31, VE-Cadherin, Thrombomodulin, and VEGFR-2 (vascular endothelial growth factor receptor-2) and activation marker vWF gene expression was increased in different endothelial subpopulations (e.g., arterial, venous, general capillary, aerocytes) in PF. This was associated with a heightened sensitivity of fibrotic ECs to TNF-α or IFN-γ and elevated immune cell adhesion. The barrier strength was overall reduced in ECs from fibrotic lungs. vWF and IL-8 were increased in the plasma of patients, whereas VE-Cadherin, Thrombomodulin, and VEGFR-2 were decreased. VE-Cadherin staining was also patchy in biopsy tissue and was decreased in plasma samples of patients with PF 6 months after the initial diagnosis. Our data demonstrate highly abnormal ECs in PF. The vascular compartment is characterized by hyperactivation and increased immune cell adhesion, as well as dysfunctional endothelial barrier function. Reestablishing EC homeostasis and function might represent a new therapeutic option for fibrotic lung diseases.

The pulmonary vasculature has been frequently overlooked in acute and chronic lung diseases, such as acute respiratory distress syndrome (ARDS), pulmonary fibrosis (PF), and chronic obstructive pulmonary disease (COPD). The primary emphasis in the management of these parenchymal disorders has largely revolved around the injury and aberrant repair of epithelial cells. However, there is increasing evidence that the vascular endothelium plays an active role in the development of acute and chronic lung diseases. The endothelial cell network in the capillary bed and the arterial and venous vessels provides a metabolically highly active barrier that controls the migration of immune cells, regulates vascular tone and permeability, and participates in the remodeling processes. Phenotypically and functionally altered endothelial cells, and remodeled vessels, can be found in acute and chronic lung diseases, although to different degrees, likely because of disease-specific mechanisms. Since vascular remodeling is associated with pulmonary hypertension, which worsens patient outcomes and survival, it is crucial to understand the underlying vascular alterations. In this Review, we describe the current knowledge regarding the role of the pulmonary vasculature in the development and progression of ARDS, PF, and COPD; we also outline future research directions with the hope of facilitating the development of mechanism-based therapies.

Pulmonary arterial hypertension (PAH) is a chronic, incurable condition characterized by pulmonary vascular remodeling, perivascular inflammation, and right heart failure. Regulatory T cells (Tregs) stave off autoimmunity, and there is increasing evidence for their compromised activity in the inflammatory milieu of PAH. Abnormal Treg function is strongly correlated with a predisposition to PAH in animals and patients. Athymic Treg-depleted rats treated with SU5416, an agent causing pulmonary vascular injury, develop PAH, which is prevented by infusing missing CD4 + CD25 high FOXP3 + Tregs. Abnormal Treg activity may also explain why PAH disproportionately affects women more than men. This mini review focuses on the role of Tregs in PAH with a special view to sexual dimorphism and the future promise of Treg therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Tian, Jiang, Jiang, Tamosiuniene, Kim, Guan, Arsalane, Pasupneti, Voelkel, Tang and Nicolls.)

Background: Up to 50% of chronic obstructive pulmonary disease (COPD) patients do not receive recommended care for COPD. To address this issue, we developed Proactive Integrated Care (Proactive iCare), a health care delivery model that couples integrated care with remote monitoring., Methods: We conducted a prospective, quasi-randomized clinical trial in 511 patients with advanced COPD or a recent COPD exacerbation, to test whether Proactive iCare impacts patient-centered outcomes and health care utilization. Patients were allocated to Proactive iCare (n=352) or Usual Care ( =159) and were examined for changes in quality of life using the St George's Respiratory Questionnaire (SGRQ), symptoms, guideline-based care, and health care utilization., Findings: Proactive iCare improved total SGRQ by 7-9 units ( p < 0.0001), symptom SGRQ by 9 units ( p <0.0001), activity SGRQ by 6-7 units (p <0.001) and impact SGRQ by 7-11 units ( p <0.0001) at 3, 6 and 9 months compared with Usual Care. Proactive iCare increased the 6-minute walk distance by 40 m ( p <0.001), reduced annual COPD-related urgent office visits by 76 visits per 100 participants (p <0.0001), identified unreported exacerbations, and decreased smoking ( p =0.01). Proactive iCare also improved symptoms, the b ody mass index-airway o bstruction- d yspnea- e xercise tolerance (BODE) index and oxygen titration ( p <0.05). Mortality in the Proactive iCare group (1.1%) was not significantly different than mortality in the Usual Care group (3.8%; p =0.08)., Interpretation: Linking integrated care with remote monitoring improves the lives of people with advanced COPD, findings that may have been made more relevant by the coronavirus 2019 (COVID-19) pandemic., Competing Interests: RWV, PBK, SJM, DLPD, TJF, SSJ, NFV, DJL, AB, TJS, DPR, CMK, SC, RLK and JMW received funding from the Colorado Cancer, Cardiovascular Disease and Chronic Pulmonary Disease Prevention, Early Detection and Treatment Program (CCPD). RWV and MG received funding from the National Institutes of Health. PBK worked for Robert Bosch Healthcare from 2010 to 2015 and for Philips Healthcare from 2015 to 2017, after the study was completed. RKA, FDV, JKZ and TMB had no conflicts of interest., (JCOPDF © 2021.)

Background: In animal models of pulmonary arterial hypertension (PAH), angiotensin-converting enzyme (ACE)2 and angiotensin (Ang)-(1-7) have been shown to have vasodilatory, antiproliferative, antifibrotic and antihypertrophic properties. However, the status and role of the ACE2-Ang(1-7) axis in human PAH is incompletely understood., Methods: We studied 85 patients with a diagnosis of PAH of distinct aetiologies. 55 healthy blood donors paired for age and sex served as controls. Blood samples were obtained from the pulmonary artery in patients with PAH during right heart catheterisation. Peripheral blood was obtained for both groups. Ang(1-7) and -II were measured using zone capillary electrophoresis. Aldosterone, Ang(1-9), AngA and ACE2 were measured using ELISA, and ACE2 activity was determined enzymatically., Results: Of the 85 patients, 47 had idiopathic PAH, 25 had PAH associated with congenital heart disease and 13 had PAH associated with collagen vascular disease. Compared to controls, patients with PAH had a higher concentration of AngII (median 1.03, interquartile range 0.72-1.88 pmol·mL -1 versus 0.19, 0.10-0.37 pmol·mL -1 ; p<0.001) and of aldosterone (88.7, 58.7-132 ng·dL -1 versus 12.9, 9.55-19.9 ng·dL -1 ; p<0.001). Conversely, PAH patients had a lower concentration of Ang(1-7) than controls (0.69, 0.474-0.91 pmol·mL -1 versus 4.07, 2.82-6.73 pmol·mL -1 ; p<0.001), and a lower concentration of Ang(1-9) and AngA. Similarly, the ACE2 concentration was higher than in controls (8.7, 5.35-13.2 ng·mL -1 versus 4.53, 1.47-14.3 ng·mL -1 ; p=0.011), whereas the ACE2 activity was significantly reduced (1.88, 1.08-2.81 nmol·mL -1 versus 5.97, 3.1-17.8 nmol·mL -1 ; p<0.001). No significant differences were found among the three different aetiological forms of PAH., Conclusions: The AngII-ACE2-Ang(1-7) axis appears to be altered in human PAH and we propose that this imbalance, in favour of AngII, plays a role in the pathogenesis of the severe PAH. Further mechanistic studies are warranted., Competing Interests: Conflict of interest: J. Sandoval has nothing to disclose. Conflict of interest: L. Del Valle-Mondragón has nothing to disclose. Conflict of interest: F. Masso has nothing to disclose. Conflict of interest: N. Zayas has nothing to disclose. Conflict of interest: T. Pulido reports grants from and personal fees for advisory board work and lectures from Actelion and Bayer, grants from Lilly, Reata Pharmaceuticals and United Therapeutics, personal fees for advisory board work from Pfizer and Akros Pharma, outside the submitted work. Conflict of interest: R. Teijeiro reports grants from CONACYT (FOSISS project 2015-1-262511), during the conduct of the study. Conflict of interest: H. González-Pacheco has nothing to disclose. Conflict of interest: R. Olmedo-Ocampo has nothing to disclose. Conflict of interest: C. Sisniega has nothing to disclose. Conflict of interest: A. Paez-Arenas has nothing to disclose. Conflict of interest: G. Pastelin-Hernandez has nothing to disclose. Conflict of interest: J. Gómez-Arroyo has nothing to disclose. Conflict of interest: N.F. Voelkel has nothing to disclose., (Copyright ©ERS 2020.)

Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared with the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.

It has been generally accepted that severe forms of pulmonary arterial hypertension are associated with inflammation. Plasma levels in patients with severe pulmonary arterial hypertension show elevated levels of interleukins and mediators of inflammation and histologically the diseased small pulmonary arterioles show infiltrates of inflammatory and immune cells. Here, we review the literature that connects pulmonary hypertension with the arachidonic acid/5-lipoxygenase-derived leukotriens. This mostly preclinical background data together with the availability of 5-lipoxygenase inhibitors and leukotriene receptor blockers provide the rationale for testing the hypothesis that 5-lipoxygenase products contribute to the pathobiology of severe pulmonary arterial hypertension in a subgroup of patients., (© The Author(s) 2020.)

Pulmonary arterial hypertension is a fatal disease associated with pulmonary vascular remodeling and right ventricular hypertrophy. Pre-clinical animal models that reproduce the human pulmonary arterial hypertension process and pharmacological response to available therapies are critical for future drug development. The most prevalent animal model reproducing many aspects of angioobliterative forms of pulmonary arterial hypertension is the rat Sugen/hypoxia model in which Sugen, a vascular endothelial growth factor receptor antagonist, primarily causes initiation of endothelial injury and later in the presence of hypoxia promotes proliferation of apoptosis-resistant endothelial cells. We previously demonstrated that exposure of human pulmonary microvascular endothelium to morphine and HIV-proteins results in initial apoptosis followed by increased proliferation. Here, we demonstrate that the double-hit of morphine and Sugen 5416 (Sugen-morphine) in rats leads to the development of pulmonary arterial hypertension with significant medial hypertrophy of pre-acinar pulmonary arteries along with neo-intimal thickening of intra-acinar vessels. In addition, the pulmonary smooth muscle and endothelial cells isolated from Sugen-morphine rats showed hyperproliferation and apoptotic resistance, respectively, in response to serum starvation. Our findings support that the dual hit model of Sugen 5416 and morphine provides another experimental strategy to induce significant pulmonary vascular remodeling and development of severe pulmonary arterial hypertension pathology in rats without exposure to hypoxia., (© The Author(s) 2020.)

Background: Bmpr2 (bone morphogenetic protein receptor 2) mutations are critical risk factors for hereditary pulmonary arterial hypertension (PAH) with approximately 20% of carriers developing disease. There is an unmet medical need to understand how environmental factors, such as inflammation, render Bmpr2 mutants susceptible to PAH. Overexpressing 5-LO (5-lipoxygenase) provokes lung inflammation and transient PAH in Bmpr2 +/ - mice. Accordingly, 5-LO and its metabolite, leukotriene B 4 , are candidates for the second hit. The purpose of this study was to determine how 5-LO-mediated pulmonary inflammation synergized with phenotypically silent Bmpr2 defects to elicit significant pulmonary vascular disease in rats., Methods: Monoallelic Bmpr2 mutant rats were generated and found phenotypically normal for up to 1 year of observation. To evaluate whether a second hit would elicit disease, animals were exposed to 5-LO-expressing adenovirus, monocrotaline, SU5416, SU5416 with chronic hypoxia, or chronic hypoxia alone. Bmpr2 -mutant hereditary PAH patient samples were assessed for neointimal 5-LO expression. Pulmonary artery endothelial cells with impaired BMPR2 signaling were exposed to increased 5-LO-mediated inflammation and were assessed for phenotypic and transcriptomic changes., Results: Lung inflammation, induced by intratracheal delivery of 5-LO-expressing adenovirus, elicited severe PAH with intimal remodeling in Bmpr2 +/- rats but not in their wild-type littermates. Neointimal lesions in the diseased Bmpr2 +/- rats gained endogenous 5-LO expression associated with elevated leukotriene B 4 production, as well as a transcriptomic signature similar to clinical disease, including upregulated nuclear factor Kappa B subunit (NF-κB), interleukin-6, and transforming growth factor beta (TGF-β) signaling pathways. The reversal of PAH and vasculopathy in Bmpr2 -mutant hereditary PAH patients similarly expressed 5-LO in the neointimal cells. In vitro, BMPR2 deficiency, compounded by 5-LO-mediated inflammation, generated apoptosis-resistant and proliferative pulmonary artery endothelial cells with mesenchymal characteristics. These transformed cells expressed nuclear envelope-localized 5-LO consistent with induced leukotriene B 4 production, as well as a transcriptomic signature similar to clinical disease, including upregulated nuclear factor Kappa B subunit (NF-κB), interleukin-6, and transforming growth factor beta (TGF-β) signaling pathways. The reversal of PAH and vasculopathy in Bmpr2 mutants by TGF-β antagonism suggests that TGF-β is critical for neointimal transformation., Conclusions: In a new 2-hit model of disease, lung inflammation induced severe PAH pathology in Bmpr2 +/- rats. Endothelial transformation required the activation of canonical and noncanonical TGF-β signaling pathways and was characterized by 5-LO nuclear envelope translocation with enhanced leukotriene B 4 production. This study offers an explanation of how an environmental injury unleashes the destructive potential of an otherwise silent genetic mutation.

Rationale: CYPs (cytochrome p450) are critically involved in the metabolism of xenobiotics and toxins. Given that pulmonary hypertension is strongly associated with environmental exposure, we hypothesize that CYPs play a role in the development and maintenance of pathological vascular remodeling., Objective: We sought to identify key CYPs that could link drug or hormone metabolism to the development of pulmonary hypertension., Methods and Results: We searched in Medline (PubMed) database, as well as http://www.clinicaltrials.gov, for CYPs associated with many key aspects of pulmonary arterial hypertension including, but not limited to, severe pulmonary hypertension, estrogen metabolism, inflammation mechanisms, quasi-malignant cell growth, drug susceptibility, and metabolism of the pulmonary arterial hypertension-specific drugs., Conclusions: We postulate a hypothesis where the AhR (aryl hydrocarbon receptor) mediates aberrant cell growth via expression of different CYPs associated with estrogen metabolism and inflammation.

Heart failure (HF) is usually defined by the dominantly affected heart chamber; therefore, termed right or left HF (RHF or LHF). Pulmonologists understand RHF as a complex syndrome characterized by insufficient delivery of blood from the right ventricle associated with elevated systemic venous pressure at rest or exercise. Cardiologists specify LHF by its clinical functional class and the relation to a reduced (HFrEF), preserved (HFpEF) or mid-range ejection fraction (HFmrEF). Pediatric cardiologist, dealing also with patients with a failing single ventricle, define HF as a condition of insufficient systemic oxygen delivery (DO 2 ). Certainly, pediatricians do not think of the right and left heart, or even a single ventricle as an isolated, independently acting entity. Because of the importance of cardiac interactions, the creation of a restrictive atrial communication aims at a palliative approach with the goal to diminish the congestive consequences of a dysfunctional ventricle; further to serve as a pop-off valve in order to prevent syncope and cardiovascular collapse. This review covers the background, the particular indications, the techniques and preliminary results achieved following the creation of a restrictive atrial septum defect (rASD) in different pathophysiological settings. Based on the institutional experience, percutaneous trans-catheter perforation of the atrial septum, followed by gradual balloon dilatation can be performed at any age and location worldwide. Medical institutions in low resource countries can make use of such palliating procedures in the setting of right as well as LHF independent of their pharmacological facilities., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Background: Impaired angiogenesis is assumed to be an important factor in the development of chronic thromboembolic pulmonary hypertension (CTEPH). However, the role of endothelial cells (ECs) in CTEPH remains unclear. The aim of this study was to investigate the angiogenic potential of ECs from pulmonary endarterectomy (PEA) specimens., Methods: We isolated ECs from PEA specimens (CTEPH-ECs) and control EC lines from the intact pulmonary arteries of patients with peripheral lung cancers, using a MACS system. These cells were analyzed in vitro including PCR-array analysis, and the PEA specimens were analyzed with immunohistochemistry. Additionally, the serum HGF levels were determined in CTEPH patients., Results: A three-dimensional culture assay revealed that CTEPH-ECs were highly angiogenic. An angiogenesis-focused gene PCR array revealed a high expression of hepatocyte growth factor (HGF) in CTEPH-ECs. The high expression of HGF was also confirmed in the supernatant extracted from PEA specimens. The immunohistochemical analysis showed expression of HGF on the surface of the thrombus vessels. The serum HGF levels in CTEPH patients were higher than those in pulmonary thromboembolism survivors., Conclusion: Our study suggests that there are ECs with pro-angiogenetic character and high expression of HGF in PEA specimens. It remains unknown how these results are attributable to the etiology. However, further investigation focused on the HGF pathway may provide novel diagnostic and therapeutic tools for patients with CTEPH.

Background: Left atrial decompression is considered in patients with symptomatic heart failure with preserved ejection fraction (HFpEF). We aimed to evaluate the feasibility and efficacy of transcatheter generation of a restrictive atrial septum communication to manage HFpEF from infancy to adulthood with cardiomyopathy and congenital heart defect., Methods and Results: From June 2009 to December 2016, 24 patients (50% with an age less than 16 years) with HFpEF were palliated; NYHA-/Ross class IV (n = 10); median systemic ventricular ejection fraction 64 (range 35-78) %. Cardiomyopathy was classified as a restrictive (n = 4) or hypertrophic (n = 2). (75% related to congenital heart defects) Three patients had a systemic right ventricle; in the majority of patients, HFpEF was associated to complex congenital heart defects (n = 18). Mean pulmonary arterial pressures (PAP systolic/diastolic) were 56/28 (± 24/13), left atrial pressures (LAP, v-, a-wave, mean) 26/25/20 (± 7/10/6). Trans-septal puncture was used in 22 patients; foramen ovale dilatation in 2 patients. Median balloon size was 12 (range 6-18) mm; procedure time including diagnostic measures 125 (83-221) min. No procedural death or complications were observed. Mean LA-pressures decreased significantly to 19/19/15 ± 6/8/5 mmHg (p = 0.05); median brain natriuretic peptide (BNP) decreased from 392 (range 93-4401) pg/ml median BNP to 314 (range 61-1544) pg/ml (p = 0.05). Three patients died; one patient received orthotopic heart and one patient a heart-lung transplantation. No patient required so far an assist device. Clinical improvement occurred in all patients, in some after additional surgical or interventional approach., Conclusions: Transcatheter LA decompression is an age-independent, effective palliation treating patients with HFpEF.

Background: Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies., Methods: A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations., Results: This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes., Conclusions: This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Rationale: Pulmonary arterial hypertension (PH) is a life-threatening condition associated with immune dysregulation and abnormal regulatory T cell (Treg) activity, but it is currently unknown whether and how abnormal Treg function differentially affects males and females., Objective: To evaluate whether and how Treg deficiency differentially affects male and female rats in experimental PH., Methods and Results: Male and female athymic rnu/rnu rats, lacking Tregs, were treated with the VEGFR2 (vascular endothelial growth factor receptor 2) inhibitor SU5416 or chronic hypoxia and evaluated for PH; some animals underwent Treg immune reconstitution before SU5416 administration. Plasma PGI 2 (prostacyclin) levels were measured. Lung and right ventricles were assessed for the expression of the vasoprotective proteins COX-2 (cyclooxygenase 2), PTGIS (prostacyclin synthase), PDL-1 (programmed death ligand 1), and HO-1 (heme oxygenase 1). Inhibitors of these pathways were administered to athymic rats undergoing Treg immune reconstitution. Finally, human cardiac microvascular endothelial cells cocultured with Tregs were evaluated for COX-2, PDL-1, HO-1, and ER (estrogen receptor) expression, and culture supernatants were assayed for PGI 2 and IL (interleukin)-10. SU5416-treatment and chronic hypoxia produced more severe PH in female than male athymic rats. Females were distinguished by greater pulmonary inflammation, augmented right ventricular fibrosis, lower plasma PGI 2 levels, decreased lung COX-2, PTGIS, HO-1, and PDL-1 expression and reduced right ventricular PDL-1 levels. In both sexes, Treg immune reconstitution protected against PH development and raised levels of plasma PGI 2 and cardiopulmonary COX-2, PTGIS, PDL-1, and HO-1. Inhibiting COX-2, HO-1, and PD-1 (programmed death 1)/PDL-1 pathways abrogated Treg protection. In vitro, human Tregs directly upregulated endothelial COX-2, PDL-1, HO-1, ERs and increased supernatant levels of PGI 2 and IL-10., Conclusions: In 2 animal models of PH based on Treg deficiency, females developed more severe PH than males. The data suggest that females are especially reliant on the normal Treg function to counteract the effects of pulmonary vascular injury leading to PH., (© 2018 American Heart Association, Inc.)

Drug-induced pulmonary arterial hypertension (D-PAH) is a form of World Health Organization Group 1 pulmonary hypertension (PH) defined by severe small vessel loss and obstructive vasculopathy, which leads to progressive right heart failure and death. To date, 16 different compounds have been associated with D-PAH, including anorexigens, recreational stimulants, and more recently, several Food and Drug Administration-approved medications. Although the clinical manifestation, pathology, and hemodynamic profile of D-PAH are indistinguishable from other forms of pulmonary arterial hypertension, its clinical course can be unpredictable and to some degree dependent on removal of the offending agent. Because only a subset of individuals develop D-PAH, it is probable that genetic susceptibilities play a role in the pathogenesis, but the characterization of the genetic factors responsible for these susceptibilities remains rudimentary. Besides aggressive treatment with PH-specific therapies, the major challenge in the management of D-PAH remains the early identification of compounds capable of injuring the pulmonary circulation in susceptible individuals. The implementation of pharmacovigilance, precision medicine strategies, and global warning systems will help facilitate the identification of high-risk drugs and incentivize regulatory strategies to prevent further outbreaks of D-PAH. The goal for this review is to inform clinicians and scientists of the prevalence of D-PAH and to highlight the growing number of common drugs that have been associated with the disease.

Fatal pulmonary arterial hypertension (PAH) affects HIV-infected individuals at significantly higher frequencies. We previously showed plexiform-like lesions characterized by recanalized lumenal obliteration, intimal disruption, medial hypertrophy, and thrombosis consistent with PAH in rhesus macaques infected with chimeric SHIVnef but not with the parental SIVmac239, suggesting that Nef is implicated in the pathophysiology of HIV-PAH. However, the current literature on non-human primates as animal models for SIV(HIV)-associated pulmonary disease reports the ultimate pathogenic pulmonary outcomes of the research efforts; however, the variability and features in the actual disease progression remain poorly described, particularly when using different viral sources for infection. We analyzed lung histopathology, performed immunophenotyping of cells in plexogenic lesions pathognomonic of PAH, and measured cardiac hypertrophy biomarkers and cytokine expression in plasma and lung of juvenile SHIVnef-infected macaques. Here, we report significant hematopathologies, changes in cardiac biomarkers consistent with ventricular hypertrophy, significantly increased levels of interleukin-12 and GM-CSF and significantly decreased sCD40 L, CCL-2, and CXCL-1 in plasma of the SHIVnef group. Pathway analysis of inflammatory gene expression predicted activation of NF-κB transcription factor RelB and inhibition of bone morphogenetic protein type-2 in the setting of SHIVnef infection. Our findings highlight the utility of SHIVnef-infected macaques as suitable models of HIV-associated pulmonary vascular remodeling as pathogenetic changes are concordant with features of idiopathic, familial, scleroderma, and HIV-PAH.

Atrial septostomy (AS) is recommended for pulmonary arterial hypertension (PAH)-associated right ventricular (RV) failure, recurrent syncope, or pulmonary hypertensive crisis (PHC). We aimed to evaluate the feasibility and efficacy of AS to manage PAH from infancy to adulthood. From June 2009 to December 2016, transcatheter atrial communications were created in 11 PAH patients (4 girls/women; median age = 4.3 years; range = 33 days-26 years; median body weight = 14 kg; range = 3-71 kg; NYHA-/Ross class IV; n = 11). PAH was classified as idiopathic (n = 6) or secondary (n = 5). History of syncope was dominant (n = 6); two with patent foramen ovale (PFO) admitted with recurrent PHC, three patients required resuscitation before AS. Three patients had PAH-associated low cardiac output. The average pulmonary arterial pressures (PAP systolic/diastolic) were 101/50 (±34/23); the corresponding systemic arterial pressures (SAP) were 99/54 (±23/11); and the mean ratio of PAPd / SAPd was 0.97 (±0.4). Percutaneous trans-septal puncture was uneventfully performed in nine patients; a PFO was dilated in two patients. There was no procedure-related mortality. The median balloon size was 10 mm (range = 6-14 mm); the mean catheter time was 174.6 ± 48 min; fluoroscopy time was 19.8 (±11) min. Syncope and PHC were successfully treated in all patients. The mean arterial oxygen saturation decreased from 97 ± 2 to 89 ± 11.7. One patient died awaiting lung transplantation, one continues to be listed; two patients received a reverse Potts-shunt, one patient died during follow-up; seven patients are stable with PAH-specific treatment. Percutaneous AS is an effective method palliating PAH-associated syncope, PHCs or right (bi-) ventricular heart failure.

Induced lung cell death and impaired hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) signaling are proposed as a pathobiologic mechanism for alveolar structural destruction and loss in emphysema. We hypothesized that our sulfated dehydropolymer of caffeic acid, CDSO3, exerts anti-cell death activities and therapeutic interventions in emphysema by virtue of Fe 2+ chelation-based HIF-1α/VEGF stabilization and elevation. The Fe 2+ chelating activity was determined in the chromogenic ferrozine-Fe 2+ chelation inhibitory assay. The in vitro anti-cell death activities and their Fe 2+ and HIF-1α dependence were assessed against a range of emphysematous insults in the lung endothelial (HMVEC-L) and epithelial (A549) cells. CDSO3 was spray-dosed to the lung for three weeks (day 1-21) in an in vivo rat model of apoptotic emphysema induced with a VEGF receptor antagonist SU5416. Post-treatment treadmill exercise endurance, airspace enlargement, and several lung biomarkers/proteins were measured. CDSO3 was a potent Fe 2+ chelating molecule. At 10 μM, CDSO3 inhibited HMVEC-L and A549 cell death induced by histone deacetylase inhibition with trichostatin A, VEGF receptor blockade with SU5416, and cigarette smoke extract by 65-99%, which were all significantly opposed by addition of excess Fe 2+ or HIF-1α inhibitors. As a potent elastase inhibitor and antioxidant, CDSO3 also inhibited elastase- and H 2 O 2 -induced cell death by 92 and 95%, respectively. In the rat model of SU5416-induced apoptotic emphysema, CDSO3 treatment at 60 μg/kg 1) produced 61-77% interventions against exercise endurance impairment, airspace enlargement [mean linear intercept] and oxidative lung damage [malondialdehyde activity]; 2) normalized the apoptotic marker [cleaved caspase-3]; 3) stimulated the VEGF signaling [VEGF receptor 2 phosphorylation] by 1.4-fold; and 4) elevated the HIF-1α and VEGF expression by 1.8- and 1.5-fold, respectively. All of these were consistent with CDSO3's Fe 2+ chelation-based HIF-1α/VEGF stabilization and elevation against their pathobiologic deficiency, inhibiting lung cell death and development of apoptotic emphysema., (Copyright © 2017. Published by Elsevier Ltd.)

Background: The p53 signaling pathway may be important for the pathogenesis of emphysematous changes in the lungs of smokers. Polymorphism of p53 at codon 72 is known to affect apoptotic effector proteins, and the polymorphism of mouse double minute 2 homolog (MDM2) single nucleotide polymorphism (SNP)309 is known to increase MDM2 expression. The aim of this study was to assess polymorphisms of the p53 and MDM2 genes in smokers and confirm the role of SNPs in these genes in the pathogenesis of pulmonary emphysema., Methods: This study included 365 patients with a smoking history, and the polymorphisms of p53 and MDM2 genes were identified. The degree of pulmonary emphysema was determined by means of CT scanning. SNPs, MDM2 mRNA, and p53 protein levels were assessed in human lung tissues from smokers. Plasmids encoding p53 and MDM2 SNPs were used to transfect human lung fibroblasts (HLFs) with or without cigarette smoke extract (CSE), and the effects on cell proliferation and MDM2 promoter activity were measured., Results: The polymorphisms of the p53 and MDM2 genes were associated with emphysematous changes in the lung and were also associated with p53 protein and MDM2 mRNA expression in the lung tissue samples. Transfection with a p53 gene-coding plasmid regulated HLF proliferation, and the analysis of P2 promoter activity in MDM2 SNP309-coding HLFs showed the promoter activity was altered by CSE., Conclusions: Our data demonstrated that p53 and MDM2 gene polymorphisms are associated with apoptotic signaling and smoking-related emphysematous changes in lungs from smokers., (Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Acquired lymphedema is a cancer sequela and a global health problem currently lacking pharmacologic therapy. We have previously demonstrated that ketoprofen, an anti-inflammatory agent with dual 5-lipoxygenase and cyclooxygenase inhibitory properties, effectively reverses histopathology in experimental lymphedema. We show that the therapeutic benefit of ketoprofen is specifically attributable to its inhibition of the 5-lipoxygenase metabolite leukotriene B 4 (LTB 4 ). LTB 4 antagonism reversed edema, improved lymphatic function, and restored lymphatic architecture in the murine tail model of lymphedema. In vitro, LTB 4 was functionally bimodal: Lower LTB 4 concentrations promoted human lymphatic endothelial cell sprouting and growth, but higher concentrations inhibited lymphangiogenesis and induced apoptosis. During lymphedema progression, lymphatic fluid LTB 4 concentrations rose from initial prolymphangiogenic concentrations into an antilymphangiogenic range. LTB 4 biosynthesis was similarly elevated in lymphedema patients. Low concentrations of LTB 4 stimulated, whereas high concentrations of LTB 4 inhibited, vascular endothelial growth factor receptor 3 and Notch pathways in cultured human lymphatic endothelial cells. Lymphatic-specific Notch1 -/- mice were refractory to the beneficial effects of LTB 4 antagonism, suggesting that LTB 4 suppression of Notch signaling is an important mechanism in disease maintenance. In summary, we found that LTB 4 was harmful to lymphatic repair at the concentrations observed in established disease. Our findings suggest that LTB 4 is a promising drug target for the treatment of acquired lymphedema., (Copyright © 2017, American Association for the Advancement of Science.)

The final therapy of 'end-stage heart failure' is orthotopic heart, lung or heart-lung transplantation. However, these options are not available for many patients worldwide. Therefore, novel therapeutical strategies are needed. Based on pathophysiological insights regarding (1) the long-term impact of an obstructive pulmonary outflow tract in neonates with congenitally corrected transposition of the great arteries, (2) the importance of a restrictive versus a non-restrictive atrial septum in neonates born with a borderline left ventricle and (3) the significance of both, a patent foramen ovale and/or open ductus arteriosus for survival of newborns with persistent pulmonary hypertension, the current review introduces some therapeutical strategies that may be applicable to selected patients with heart failure. These strategies include (1) reversible pulmonary artery banding in left ventricular-dilated cardiomyopathy with preserved right ventricular function, (2) the creation of restrictive interatrial communication to treat diastolic (systolic) heart failure, (3) atrioseptostomy or reverse Potts shunt in pulmonary arterial hypertension and (4) return to a fetal, parallel circulation by combining atrioseptostomy and reversed Potts shunt with or without placement of a bilateral pulmonary artery banding. While still being experimental, it is hoped that the procedures presented in the current overview will inspire future novel therapeutic strategies that may be applicable to selected patients with heart failure., Competing Interests: Competing interests: None., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Background: Cigarette smoke induced oxidative stress has been shown to reduce silent information regulator 1 (Sirt1) levels in lung tissue from smokers and patients with COPD patients. Sirt1 is known to inhibit endothelial senescence and may play a protective role in vascular cells. Endothelial progenitor cells (EPCs) are mobilized into circulation under various pathophysiological conditions, and are thought to play an important role in tissue repair in chronic obstructive lung disease (COPD). Therefore, Sirt1 and EPC-associated mRNAs were measured in blood samples from patients with COPD and from cultured CD34 + progenitor cells to examine whether these genes are associated with COPD development., Methods: This study included 358 patients with a smoking history of more than 10 pack-years. RNA was extracted from blood samples and from CD34 + progenitor cells treated with cigarette smoke extract (CSE), followed by assessment of CD31, CD34, Sirt1 mRNA, miR-34a, and miR-126-3p expression by real-time RT-PCR., Results: The expression of CD31, CD34, Sirt1 mRNAs, and miR-126-3p decreased and that of miR-34a increased in moderate COPD compared with that in control smokers. However, no significant differences in these genes were observed in blood cells from patients with severe COPD compared with those in control smokers. CSE significantly decreased Sirt1 and increased miR-34a expression in cultured progenitor cells., Conclusion: Sirt1 expression in blood cells from patients with COPD could be a biomarker for disease stability in patients with moderate COPD. MiR-34a may participate in apoptosis and/or senescence of EPCs in smokers. Decreased expression of CD31, CD34, and miR-126-3p potentially represents decreased numbers of EPCs in blood cell from patients with COPD.