Pulmonary arterial lesions in explanted lungs after transplantation correlate with severity of pulmonary hypertension in chronic obstructive pulmonary disease

Expiratory Venous Volume and Arterial Tortuosity are Associated with Disease Severity and Mortality Risk in Patients with COPD: Results from COSYCONET

Purpose

The aim of this study was to evaluate the association between computed tomography (CT) quantitative pulmonary vessel morphology and lung function, disease severity, and mortality risk in patients with chronic obstructive pulmonary disease (COPD).

Patients and Methods

Participants of the prospective nationwide COSYCONET cohort study with paired inspiratory-expiratory CT were included. Fully automatic software, developed in-house, segmented arterial and venous pulmonary vessels and quantified volume and tortuosity on inspiratory and expiratory scans. The association between vessel volume normalised to lung volume and tortuosity versus lung function (forced expiratory volume in 1 sec [FEV1]), air trapping (residual volume to total lung capacity ratio [RV/TLC]), transfer factor for carbon monoxide (TLCO), disease severity in terms of Global Initiative for Chronic Obstructive Lung Disease (GOLD) group D, and mortality were analysed by linear, logistic or Cox proportional hazard regression.

Results

Complete data were available from 138 patients (39% female, mean age 65 years). FEV1, RV/TLC and TLCO, all as % predicted, were significantly (p < 0.05 each) associated with expiratory vessel characteristics, predominantly venous volume and arterial tortuosity. Associations with inspiratory vessel characteristics were absent or negligible. The patterns were similar for relationships between GOLD D and mortality with vessel characteristics. Expiratory venous volume was an independent predictor of mortality, in addition to FEV1.

Conclusion

By using automated software in patients with COPD, clinically relevant information on pulmonary vasculature can be extracted from expiratory CT scans (although not inspiratory scans); in particular, expiratory pulmonary venous volume predicted mortality.

Trial Registration

NCT01245933.

Compartment-specific remodeling patterns in end-stage chronic obstructive pulmonary disease with and without severe pulmonary hypertension

BACKGROUND

In patients with end-stage chronic obstructive pulmonary disease (COPD), severe pulmonary hypertension (PH) is frequently associated with less severe airway obstruction as compared to mild or no PH. However, the histologic correlate of this finding is not clear. We aimed to quantify remodeling of pulmonary arteries, airways, and parenchyma in random samples of explanted end-stage COPD lungs.

METHODS

We quantified remodeling of small pulmonary arteries, small airways, and the degree of emphysema (mean interseptal distance [MID]) with dedicated software. As primary objective, we compared COPD patients with severe PH (SevPH-COPD) with age- and sex-matched MildPH-COPD. For comparison, we also investigated COPD lungs with no PH (NoPH-COPD), idiopathic PAH (IPAH), and healthy donors.

RESULTS

We included n = 17 SevPH-COPD (mPAP = 43 [39-45]mm Hg), n = 17 MildPH-COPD (mPAP = 28 [24-31]mm Hg), n = 5 NoPH-COPD (mPAP = 18 [16-19]mm Hg), n = 10 IPAH (mPAP = 72 [65-91]mm Hg), and n = 10 healthy donor lungs. SevPH-COPD versus MildPH-COPD was characterized by better preserved forced vital capacity (51% vs 40% predicted, p < 0.05), less emphysema (MID 169 µm vs 279 µm, p < 0.001), and less PAS-positive and CD45-positive mucosa cells (15% vs 22%, p = 0.063% and 5% vs 7%, p = 0.058) suggesting less airway inflammation. In COPD patients, intimal and medial thickening were strongly correlated with mPAP (r = 0.676, p < 0.001 and r = 0.595, p < 0.001). MID was negatively correlated with mPAP (r = -0.556, p < 0.001) and was highest in NoPH-COPD (mean 281 µm), suggesting that emphysema per se is not associated with PH.

CONCLUSIONS

End-stage COPD with severe PH is characterized by pronounced pulmonary vascular remodeling, less inflammation of small airways, and less emphysema as compared to COPD with mild PH or no PH, suggesting that COPD with severe PH may represent a unique phenotype of COPD.

Transcriptomics and proteomics revealed sex differences in human pulmonary microvascular endothelial cells

Marked sexual dimorphism is displayed in the onset and progression of pulmonary hypertension (PH). Females more commonly develop pulmonary arterial hypertension, yet females with pulmonary arterial hypertension and other types of PH have better survival than males. Pulmonary microvascular endothelial cells play a crucial role in pulmonary vascular remodeling and increased pulmonary vascular resistance in PH. Given this background, we hypothesized that there are sex differences in the pulmonary microvascular endothelium basally and in response to hypoxia that are independent of the sex hormone environment. Human pulmonary microvascular endothelial cells (HPMECs) from healthy male and female donors, cultured under physiological shear stress, were analyzed using RNA sequencing and label-free quantitative proteomics. Gene set enrichment analysis identified a number of sex-different pathways in both normoxia and hypoxia, including pathways that regulate cell proliferation. In vitro, the rate of proliferation in female HPMECs was lower than in male HPMECs, a finding that supports the omics results. Interestingly, thrombospondin-1, an inhibitor of proliferation, was more highly expressed in female cells than in male cells. These results demonstrate, for the first time, important differences between female and male HPMECs that persist in the absence of sex hormone differences and identify novel pathways for further investigation that may contribute to sexual dimorphism in pulmonary hypertensive diseases.NEW & NOTEWORTHY There is marked sexual dimorphism in the development and progression of pulmonary hypertension. We show differences in RNA and protein expression between female and male human pulmonary microvascular endothelial cells grown under conditions of physiological shear stress, which identify sex-different cellular pathways both in normoxia and hypoxia. Importantly, these differences were detected in the absence of sex hormone differences. The pathways identified may provide novel targets for the development of sex-specific therapies.

Pulmonary Vasodilator Therapy in Severe Pulmonary Hypertension Due to Chronic Obstructive Pulmonary Disease (Severe PH-COPD): A Systematic Review and Meta-Analysis

Background: Chronic obstructive pulmonary disease-associated pulmonary hypertension (PH-COPD) results in a significant impact on symptoms, quality of life, and survival. There is scant and conflicting evidence about the use of pulmonary hypertension (PH) specific therapy in patients with PH-COPD. Study Design and Methods: PubMed, OVID, CINAHL, Cochrane, Embase, and Web of Science were searched using various MESH terms to identify randomized controlled trials (RCTs) or observational studies investigating PH-specific therapies in patients with severe PH-COPD, defined by mean pulmonary artery pressure (mPAP) of more than 35 mm Hg or pulmonary vascular resistance (PVR) of more than 5 woods units on right heart catheterization. The primary outcome was a change in mPAP and PVR. Secondary outcomes were changes in six-minute walk distance (6MWD), changes in the brain-natriuretic peptide (BNP), New York Heart Association (NYHA) functional class, oxygenation, and survival. Results: Thirteen studies satisfied the inclusion criteria, including a total of 328 patients with severe PH-COPD. Out of these, 308 patients received some type of specific therapy for PH. There was a significant reduction in mPAP (mean difference (MD) -3.68, 95% CI [-2.03, -5.32], p < 0.0001) and PVR (MD -1.40 Wood units, 95% CI [-1.97, -0.82], p < 0.00001). There was a significant increase in the cardiac index as well (MD 0.26 L/min/m2, 95% CI [0.14, 0.39], p < 0.0001). There were fewer patients who had NYHA class III/lV symptoms, with an odds ratio of 0.55 (95% CI [0.30, 1.01], p = 0.05). There was no significant difference in the 6MWD (12.62 m, 95% CI [-8.55, 33.79], p = 0.24), PaO2 (MD -2.20 mm Hg, 95% CI [-4.62, 0.22], p = 0.08), or BNP or NT-proBNP therapy (MD -0.15, 95% CI [-0.46, 0.17], p = 0.36). Conclusion: The use of PH-specific therapies in severe PH-COPD resulted in a significant reduction in mPAP and PVR and increased CI, with fewer patients remaining in NYHA functional class III/IV. However, no significant difference in the 6MWD, biomarkers of right ventricular dysfunction, or oxygenation was identified, demonstrating a lack of hypoxemia worsening with treatment. Further studies are needed to investigate the use of PH medications in patients with severe PH-COPD.

Management of Pulmonary Hypertension Associated with Chronic Lung Disease

Pulmonary hypertension (PH) is a common complication of chronic lung diseases, particularly in chronic obstructive pulmonary disease (COPD) and interstitial lung diseases (ILD) and especially in advanced disease. It is associated with greater mortality and worse clinical course. Given the high prevalence of some respiratory disorders and because lung parenchymal abnormalities might be present in other PH groups, the appropriate diagnosis of PH associated with respiratory disease represents a clinical challenge. Patients with chronic lung disease presenting symptoms that exceed those expected by the pulmonary disease should be further evaluated by echocardiography. Confirmatory right heart catheterization is indicated in candidates to surgical treatments, suspected severe PH potentially amenable with targeted therapy, and, in general, in those conditions where the result of the hemodynamic assessment will determine treatment options. The treatment of choice for these patients who are hypoxemic is long-term oxygen therapy and pulmonary rehabilitation to improve symptoms. Lung transplant is the only curative therapy and can be considered in appropriate cases. Conventional vasodilators or drugs approved for pulmonary arterial hypertension (PAH) are not recommended in patients with mild-to-moderate PH because they may impair gas exchange and their lack of efficacy shown in randomized controlled trials. Patients with severe PH (as defined by pulmonary vascular resistance >5 Wood units) should be referred to a center with expertise in PH and lung diseases and ideally included in randomized controlled trials. Targeted PAH therapy might be considered in this subset of patients, with careful monitoring of gas exchange. In patients with ILD, inhaled treprostinil has been shown to improve functional ability and to delay clinical worsening.

[Pulmonary hypertension associated with lung disease]

Lung diseases and hypoventilation syndromes are often associated with pulmonary hypertension (PH). In most cases, PH is not severe. This is defined hemodynamically by a mean pulmonary arterial pressure (PAPm) > 20 mmHg, a pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and a pulmonary vascular resistance of ≤ 5 Wood units (WU). Both the non-severe (PVR ≤ 5 WU) and much more the severe PH (PVR > 5 WU) have an unfavorable prognosis.If PH is suspected, it is recommended to primarily check whether risk factors for pulmonary arterial hypertension (PAH, group 1 PH) or chronic thromboembolic pulmonary hypertension (CTEPH, group 4 PH) are present. If risk factors are present or there is a suspicion of severe PH in lung patients, it is recommended that the patient should be presented to a PH outpatient clinic promptly.For patients with severe PH associated with lung diseases, personalized, individual therapy is recommended - if possible within the framework of therapy studies. Currently, a therapy attempt with PH specific drugs should only be considered in COPD patients if the associated PH is severe and a "pulmonary vascular" phenotype (severe precapillary PH, but typically only mild to moderate airway obstruction, no or mild hypercapnia and DLCO < 45 % of predicted value) is present. In patients with severe PH associated with interstitial lung disease phosphodiesterase-5-inhibitors may be considered in individual cases. Inhaled treprostinil may be considered also in non-severe PH in this patient population.

The vascular perspective on acute and chronic lung disease

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.

Severe Pulmonary Hypertension in COPD: Impact on Survival and Diagnostic Approach

BACKGROUND

Severe pulmonary hypertension (PH) is prognostically highly relevant in patients with COPD. The criteria for severe PH have been defined based on hemodynamic thresholds in right heart catheterization.

RESEARCH QUESTION

Can noninvasive clinical tools predict severe PH in patients with COPD? How does the mortality risk change with increasing severity of airflow limitation and pulmonary vascular disease?

STUDY DESIGN AND METHODS

We retrospectively analyzed all consecutive patients with COPD with suspected PH undergoing in-depth clinical evaluation, including right heart catheterization, in our PH clinic between 2005 and 2018. Clinical variables potentially indicative of severe PH or death were analyzed using univariate and stepwise multivariate logistic regression and Cox regression analysis adjusted for age and sex.

RESULTS

We included 142 patients with median FEV1 of 55.0% predicted (interquartile range [IQR], 42.4%-69.4% predicted) and mean pulmonary arterial pressure of 35 mm Hg (IQR, 27-43 mm Hg). A multivariate model combining echocardiographic systolic pulmonary arterial pressure of ≥ 56 mm Hg, N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels of ≥ 650 pg/mL, and pulmonary artery (PA) to ascending aorta (Ao) diameter ratio on chest CT scan of ≥ 0.93 predicted severe PH with high positive and negative predictive values (both 94%). After correction for age and sex, both airflow limitation (P = .002; Global Initiative for Chronic Obstructive Lung Disease [GOLD] stages 1-2 vs stage 3: hazard ratio [HR], 1.56 [95% CI, 0.90-2.71]; GOLD stages 1-2 vs stage 4: HR, 3.45 [95% CI, 1.75-6.79]) and PH severity (P = .012; HR, 1.85 [95% CI, 1.15-2.99]) remained associated independently with survival. The combination of GOLD stages 3 and 4 airflow limitation and severe PH showed the poorest survival (HR for death, 3.26 [95% CI, 1.62-6.57; P = .001] vs GOLD stages 1-2 combined with nonsevere PH).

INTERPRETATION

In patients with COPD, the combination of echocardiography, NT-proBNP level, and PA to Ao diameter ratio predicts severe PH with high sensitivity and specificity. The contribution of severe PH and severe airflow limitation to impaired survival is comparable.

Knocking Out of CEACAM1 Can Reduce Oxidative Stress and Promote Cell Proliferation in the HPMVECs under Hypoxia

Pulmonary hypertension (PH) induced by hypoxia is common in clinical practice and often suggests a poor prognosis. The oxidative stress and proliferation of pulmonary vascular endothelial cells caused by hypoxia are the major mechanisms involved in the pathophysiology of PH. It has been reported in recent years that the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes angiogenesis. In this study, normal human pulmonary microvascular endothelial cells (HPMVECs) and HPMVECs with stable knockout of CEACAM1 by CRISPR-Cas9 were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to induce hypoxic conditions. JC-1, ROS, and cell cycle profile were analyzed for each cell line and controls, using flow cytometry. A tube formation assay was used to detect angiogenesis, along with expression levels of CEACAM1, TNF-α, VEGF, VEGFR-2, p-P38/P38, and CyclinD1 proteins (to distinguish profiles of angiogenic growth and cell proliferation). We observed increased expression of CEACAM1 in HPMVECs after OGD/R, while ROS production was reduced and mitochondrial membrane potential was increased after OGD/R in CEACAM1^−/− HPMVECs. Furthermore, we observed increased cell division in CEACAM^−/− HPMVECs, accompanied by enhanced angiogenesis and reduced TNF-α protein expression and increased VEGF, VEGFR-2, and CyclinD1 expression. Together, these data suggest that upregulation of CEACAM1 in HPMVECs under hypoxic conditions may damage cells by increasing oxidative stress and inhibiting cell proliferation.

Group 3 Pulmonary Hypertension: From Bench to Bedside

Pulmonary hypertension (PH) because of chronic lung disease is categorized as Group 3 PH in the most recent classification system. Prevalence of these diseases is increasing over time, creating a growing need for effective therapeutic options. Recent approval of the first pulmonary arterial hypertension therapy for the treatment of Group 3 PH related to interstitial lung disease represents an encouraging advancement. This review focuses on molecular mechanisms contributing to pulmonary vasculopathy in chronic hypoxia, the pathology and epidemiology of Group 3 PH, the right ventricular dysfunction observed in this population and clinical trial data that inform the use of pulmonary vasodilators in Group 3 PH.

Echocardiography Nomogram for Predicting Survival among Chronic Lung Disease Patients with Severe Pulmonary Hypertension

Severe pulmonary hypertension in chronic lung diseases (severe CLD-PH) differs significantly from other types of PH in physiology and prognosis. We aimed to assess whether echocardiography helps predict long-term survival in patients with severe CLD-PH. This single-centre, observational cohort study enrolled 100 patients with severe CLD-PH (mean pulmonary arterial pressure ≥35 mm Hg or ≥25 mm Hg with cardiac index <2.0 L/min/m2 or pulmonary vascular resistance ≥6 Wood units) between 2009 and 2014. The population was randomly divided into a derivation and validation cohort in a 2:1 ratio. To construct a nomogram, a multivariable logistic regression model was applied, and scores were assigned based on the hazard ratio of independent echocardiographic predictors. Multivariate Cox hazards analysis identified the strongest predictors of mortality as pulmonary arterial systolic pressure (PASP), tricuspid annular plane systolic excursion, and right ventricular end-diastolic transverse dimension. The three independent predictors were entered into the nomogram. Compared with PASP alone, the nomogram resulted in an integrated discrimination improvement of 15.5% (95% confidence interval, 5.52−25.5%, p = 0.002) with a net improvement in model discrimination (C-statistic from 0.591 to 0.746). Using echocardiographic parameters, we established and validated a novel nomogram to predict all-cause death for patients with severe CLD-PH.

The Roles of S100A4 and the EGF/EGFR Signaling Axis in Pulmonary Hypertension with Right Ventricular Hypertrophy

Pulmonary hypertension (PH) is characterized by increased pulmonary arterial pressure caused by the accumulation of mesenchymal-like cells in the pulmonary vasculature. PH can lead to right ventricular hypertrophy (RVH) and, ultimately, heart failure and death. In PH etiology, endothelial-to-mesenchymal transition (EndMT) has emerged as a critical process governing the conversion of endothelial cells into mesenchymal cells, and S100A4, EGF, and EGFR are implicated in EndMT. However, a potential role of S100A4, EGF, and EGFR in PH has to date not been elucidated. We therefore quantified S100A4, EGF, and EGFR in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH). To determine specificity for unilateral heart disease, the EndMT biomarker signature was further compared between PH patients presenting with RVH and patients suffering from aortic valve stenosis (AVS) with left ventricular hypertrophy. Reduced S100A4 concentrations were found in CTEPH and iPAH patients with RVH. Systemic EGF was increased in CTEPH but not in iPAH, while AVS patients displayed slightly diminished EGF levels. EGFR was downregulated in all patient groups when compared to healthy controls. Longitudinal data analysis revealed no effect of surgical therapies on EndMT markers. Pulmonary thrombo-endarterectomized samples were devoid of S100A4, while S100A4 tissue expression positively correlated with higher grades of Heath–Edwards histopathological lesions of iPAH-derived lung tissue. Histologically, EGFR was not detectable in CTEPH lungs or in iPAH lesions. Together, our data suggest an intricate role for S100A4 and EGF/EGFR in PH with right heart pathology.

Vascular remodeling of the small pulmonary arteries and measures of vascular pruning on computed tomography

Pulmonary hypertension is characterized histologically by intimal and medial thickening in the small pulmonary arteries, eventually resulting in vascular “pruning.” Computed tomography (CT)-based quantification of pruning is associated with clinical measures of pulmonary hypertension, but it is not established whether CT-based pruning correlates with histologic arterial remodeling. Our sample consisted of 138 patients who underwent resection for early-stage lung adenocarcinoma. From histologic sections, we identified small pulmonary arteries and measured the relative area comprising the intima and media (VWA%), with higher VWA% representing greater histologic remodeling. From pre-operative CTs, we used image analysis algorithms to calculate the small vessel volume fraction (BV5/TBV) as a CT-based indicator of pruning (lower BV5/TBV represents greater pruning). We investigated relationships of CT pruning and histologic remodeling using Pearson correlation, simple linear regression, and multivariable regression with adjustment for age, sex, height, weight, smoking status, and total pack-years. We also tested for effect modification by sex and smoking status. In primary models, more severe CT pruning was associated with greater histologic remodeling. The Pearson correlation coefficient between BV5/TBV and VWA% was –0.41, and in linear regression models, VWA% was 3.13% higher (95% CI: 1.95–4.31%, p < 0.0001) per standard deviation lower BV5/TBV. This association persisted after multivariable adjustment. We found no evidence that these relationships differed by sex or smoking status. Among individuals who underwent resection for lung adenocarcinoma, more severe CT-based vascular pruning was associated with greater histologic arterial remodeling. These findings suggest CT imaging may be a non-invasive indicator of pulmonary vascular pathology.

Critical Role of Caveolin-1 Loss/Dysfunction in Pulmonary Hypertension

Pulmonary hypertension (PH) is a rare disease with a high morbidity and mortality rate. A number of systemic diseases and genetic mutations are known to lead to PH. The main features of PH are altered vascular relaxation responses and the activation of proliferative and anti-apoptotic pathways, resulting in pulmonary vascular remodeling, elevated pulmonary artery pressure, and right ventricular hypertrophy, ultimately leading to right heart failure and premature death. Important advances have been made in the field of pulmonary pathobiology, and several deregulated signaling pathways have been shown to be associated with PH. Clinical and experimental studies suggest that, irrespective of the underlying disease, endothelial cell disruption and/or dysfunction play a key role in the pathogenesis of PH. Endothelial caveolin-1, a cell membrane protein, interacts with and regulates several transcription factors and maintains homeostasis. Disruption of endothelial cells leads to the loss or dysfunction of endothelial caveolin-1, resulting in reciprocal activation of proliferative and inflammatory pathways, leading to cell proliferation, medial hypertrophy, and PH, which initiates PH and facilitates its progression. The disruption of endothelial cells, accompanied by the loss of endothelial caveolin-1, is accompanied by enhanced expression of caveolin-1 in smooth muscle cells (SMCs) that leads to pro-proliferative and pro-migratory responses, subsequently leading to neointima formation. The neointimal cells have low caveolin-1 and normal eNOS expression that may be responsible for promoting nitrosative and oxidative stress, furthering cell proliferation and metabolic alterations. These changes have been observed in human PH lungs and in experimental models of PH. In hypoxia-induced PH, there is no endothelial disruption, loss of endothelial caveolin-1, or enhanced expression of caveolin-1 in SMCs. Hypoxia induces alterations in membrane composition without caveolin-1 or any other membrane protein loss. However, caveolin-1 is dysfunctional, resulting in cell proliferation, medial hypertrophy, and PH. These alterations are reversible upon removal of hypoxia, provided there is no associated EC disruption. This review examined the role of caveolin-1 disruption and dysfunction in PH.

Pulmonary vasculopathy in explanted lungs from patients with interstitial lung disease undergoing lung transplantation

BACKGROUND

Pulmonary hypertension (PH) causes increased morbidity and mortality in patients with interstitial lung diseases (ILD). Classification schemes, while well-characterised for the vasculopathy of idiopathic PH, have been applied, unchallenged, to ILD-related PH. We evaluated pulmonary arterial histopathology in explanted human lung tissue from patients who were transplanted for advanced fibrotic ILD.

METHODS

Lung explants from 38 adult patients who underwent lung transplantation were included. Patients were divided into three groups: none, mild/moderate and severe PH by mean pulmonary artery pressure (mPAP) measured at pre lung transplantation right heart catheterisation (RHC). Grading of pulmonary vasculopathy according to Heath and Edwards scheme, and prelung transplantation evaluation data were compared between the groups.

RESULTS

38 patients with fibrotic ILDs were included, the majority (21) with idiopathic pulmonary fibrosis. Of the 38 patients, 18 had severe PH, 13 had mild/moderate PH and 7 had no PH by RHC. 16 of 38 patients had severe pulmonary arterial vasculopathy including vascular occlusion with intimal fibrosis and/or plexiform lesions. There were no correlations between mPAP and lung diffusion with the severity of pulmonary arterial pathological grade (Spearman's rho=0.14, p=0.34, rho=0.11, p=0.49, respectively).

CONCLUSIONS

Patients with end stage ILD had severe pulmonary arterial vasculopathy in their explanted lungs irrespective of the presence and/or severity of PH as measured by RHC. These findings suggest that advanced pulmonary arterial vasculopathy is common in patients with advanced fibrotic ILD and may develop prior to the clinical detection of PH by RHC.

Severe pulmonary hypertension associated with chronic obstructive pulmonary disease: A prospective French multicenter cohort

BACKGROUND

A small proportion of patients with chronic obstructive pulmonary disease (COPD) patients present severe pulmonary hypertension (PH), defined by mean pulmonary artery pressure (mPAP) ≥35 mm Hg measured by right heart catheterization. Little is known about the characteristics of severe PH-COPD. The aim of the study based on a national registry was to describe this phenotype.

METHODS

We prospectively included and followed patients with incident PH-COPD. Clinical, functional, hemodynamic data at inclusion and follow-up were retrieved. Survival assessed by Kaplan-Meier analysis was the primary end-point.

RESULTS

From 2012 to 2016, 99 patients from 13 French centers were included in the study (82 males; median age 66.0 years [interquartile range 62.0-72.0]). At inclusion, most patients had marked dyspnea (55.6% and 22.2% New York Heart Association class III and IV, respectively). During 12 months before inclusion, 42.9% had an exacerbation requiring a hospitalization. Pulmonary function tests showed a moderate obstructive pattern with median (interquartile range) FEV₁ 50.0 [35.0-63.0] % predicted and low diffusing capacity for carbon monoxide, median 20.0 [16.5-30.6] % predicted. The median values for PaO₂ and PaCO₂ on room air were 50.0 [44.8-62.0] and 36.0 [31.1-43.0] mm Hg. Median values of mPAP, pulmonary artery occlusion pressure, cardiac index and pulmonary vascular resistance were 42.0 [37.0-48.0] mm Hg, 11.0 [9.0-14.0] mm Hg, 3.0 [2.4-3.6] L/min/m², and 6.3 [4.2-7.9] WU, respectively. Mean restricted survival was 15.0 [13.9-16.0] months.

CONCLUSIONS

Severe PH-COPD is characterized by moderate airway obstruction but marked dyspnea and marked hypoxemia, low DLCO and high mPAP. This phenotype is associated with poor prognosis.

Roles of Genetic Predisposition in the Sex Bias of Pulmonary Pathophysiology, as a Function of Estrogens : Sex Matters in the Prevalence of Lung Diseases

In addition to studies focused on estrogen mediation of sex-different regulation of systemic circulations, there is now increasing clinical relevance and research interests in the pulmonary circulation, in terms of sex differences in the morbidity and mortality of lung diseases such as inherent-, allergic- and inflammatory-based events. Thus, female predisposition to pulmonary artery hypertension (PAH) is an inevitable topic. To better understand the nature of sexual differentiation in the pulmonary circulation, and how heritable factors, in vivo- and/or in vitro-altered estrogen circumstances and changes in the live environment work in concert to discern the sex bias, this chapter reviews pulmonary events characterized by sex-different features, concomitant with exploration of how alterations of genetic expression and estrogen metabolisms trigger the female-predominant pathological signaling. We address the following: PAH (Sect.7.2) is characterized as an estrogenic promotion of its incidence (Sect. 7.2.2), as a function of specific germline mutations, and as an estrogen-elicited protection of its prognosis (Sect.7.2.1). More detail is provided to introduce a less recognized gene of Ephx2 that encodes soluble epoxide hydrolase (sEH) to degrade epoxyeicosatrienic acids (EETs). As a susceptible target of estrogen, Ephx2/sEH expression is downregulated by an estrogen-dependent epigenetic mechanism. Increases in pulmonary EETs then evoke a potentiation of PAH generation, but mitigation of its progression, a phenomenon similar to the estrogen-paradox regulation of PAH. Additionally, the female susceptibility to chronic obstructive pulmonary diseases (Sect. 7.3) and asthma (Sect.7.4), but less preference to COVID-19 (Sect. 7.5), and roles of estrogen in their pathogeneses are briefly discussed.

Pulmonary Hypertension in Patients With COPD: Results From the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA)

BACKGROUND

Pulmonary hypertension (PH) in COPD is a poorly investigated clinical condition.

RESEARCH QUESTION

Which factors determine the outcome of PH in COPD?

STUDY DESIGN AND METHODS

We analyzed the characteristics and outcome of patients enrolled in the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) with moderate or severe PH in COPD as defined during the 6th PH World Symposium who received medical therapy for PH and compared them with patients with idiopathic pulmonary arterial hypertension (IPAH).

RESULTS

The population included incident patients with moderate PH in COPD (n = 68), with severe PH in COPD (n = 307), and with IPAH (n = 489). Patients with PH in COPD were older, predominantly male, and treated mainly with phosphodiesterase-5 inhibitors. Despite similar hemodynamic impairment, patients with PH in COPD achieved a worse 6-min walking distance (6MWD) and showed a more advanced World Health Organization functional class (WHO FC). Transplant-free survival rates at 1, 3, and 5 years were higher in the IPAH group than in the PH in COPD group (IPAH: 94%, 75%, and 55% vs PH in COPD: 86%, 55%, and 38%; P = .004). Risk factors for poor outcomes in PH in COPD were male sex, low 6MWD, and high pulmonary vascular resistance (PVR). In patients with severe PH in COPD, improvements in 6MWD by ≥ 30 m or improvements in WHO FC after initiation of medical therapy were associated with better outcomes.

INTERPRETATION

Patients with PH in COPD were functionally more impaired and had a poorer outcome than patients with IPAH. Predictors of death in the PH in COPD group were sex, 6MWD, and PVR. Our data raise the hypothesis that some patients with severe PH in COPD may benefit from PH treatment. Randomized controlled studies are necessary to explore this hypothesis further.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01347216; URL: www.clinicaltrials.gov.

Pulmonary hypertension in eosinophilic versus noneosinophilic COPD

BACKGROUND

The eosinophilic COPD phenotype is associated with greater airway remodelling, exacerbation risk and steroid responsiveness. However, little is known about the prevalence and characteristics of pulmonary hypertension (PH) in this patient population.

METHODS

We retrospectively evaluated a cohort of COPD patients with right heart catheterisation (RHC) data at a university hospital between January 2011 and May 2019 and compared the pulmonary vascular profile and prevalence of PH between eosinophilic and noneosinophilic patients using a definition of eosinophilic COPD as at least three blood eosinophil values ≥300 cells·µL-1. We used multivariable logistic regression analyses to examine the association between eosinophilic COPD and various PH categories adjusting for age, sex, body mass index, forced expiratory volume in 1 s (%), smoking status and use of supplemental oxygen.

RESULTS

Among 106 COPD patients with RHC data and at least three blood eosinophil values, 25% met the definition of eosinophilic COPD. Fewer patients among the eosinophilic group required long-term oxygen therapy (69% versus 93%, p=0.001) and total lung capacity was significantly lower in the eosinophilic group (p=0.006). This group had higher mean pulmonary arterial pressure (mPAP) (median (interquartile range) 30 (27-41) mmHg versus 25 (22-30) mmHg, p=0.001) and pulmonary vascular resistance (PVR) (4 (2.8-5.1) Wood units versus 2.9 (2.1-4.1) Wood units, p=0.018). On multivariable logistic regression analyses, eosinophilic phenotype was associated with PH (adjusted (a)OR 6.5, 95% CI 1.4-30.7; p=0.018) and pre-capillary PH (aOR 3.2, 95% CI 1.1-9; p=0.027), but not severe PH (aOR 2.1, 95% CI 0.6-7.2; p=0.219).

CONCLUSION

Eosinophilic COPD was associated with higher mPAP and PVR and increased likelihood of PH. More studies are needed to further explore this finding.

Diffusing Capacity Is an Independent Predictor of Outcomes in Pulmonary Hypertension Associated With COPD

BACKGROUND

Patients with COPD who experience pulmonary hypertension (PH) have worse mortality than those with COPD alone. Predictors of poor outcomes in COPD-PH are not well-described. Diffusing capacity of the lung (Dlco) assesses the integrity of the alveolar-capillary interface and thus may be a useful prognostic tool among those with COPD-PH.

RESEARCH QUESTION

Using a single center registry, we sought to evaluate Dlco as a predictor of mortality in a cohort of patients with COPD-PH.

STUDY DESIGN AND METHODS

This retrospective cohort study analyzed 71 COPD-PH patients from the Johns Hopkins Pulmonary Hypertension Registry with right-sided heart catheterization (RHC)-proven PH and pulmonary function testing data within one year of diagnostic RHC. Transplant-free survival was calculated from index RHC. Adjusted transplant-free survival was modelled using Cox proportional hazard methods; age, pulmonary vascular resistance, FEV1, oxygen use, and N-terminal pro-brain natriuretic peptide were included as covariates.

RESULTS

Overall unadjusted transplant-free 1-, 3-, and 5-year survivals were 87%, 60%, and 51%, respectively. Survival was associated with reduced Dlco across the observed range of pulmonary artery pressures and pulmonary vascular resistance. Severe Dlco impairment was associated with poorer survival (log-rank χ2 13.07) (P < .001); adjusting for covariates, for every percent predicted decrease in Dlco, mortality rates increased by 4% (hazard ratio, 1.04; 95% CI, 1.01-1.07).

INTERPRETATION

Among patients with COPD-PH, severe gas transfer impairment is associated with higher mortality, even with adjustment for airflow obstruction and hemodynamics, which suggests that Dlco may be a useful prognostic marker in this population. Future studies are needed to further investigate the association between Dlco and morbidity and to determine the utility of Dlco as a biomarker for disease risk and severity in COPD-PH.

Treatment of severe stable COPD: the multidimensional approach of treatable traits

Now that additional treatment options for severe chronic obstructive pulmonary disease (COPD) have emerged in recent years, patients with severe COPD should not be left in the rather hopeless situation of "there is nothing to improve" any more. Inertia or fatalism is a disservice to our patients. Ranging from advanced care planning to quite intense and demanding therapies such as multidisciplinary pulmonary rehabilitation, (endoscopic) lung volume reduction, chronic noninvasive ventilation and lung transplantation, caregivers should try to provide a personalised treatment for every severe COPD patient. In this review, we aim to describe the multidimensional approach to these patients at our centre along the lines of treatable traits leading to specific additional treatment modalities on top of standard care.

Updated Perspectives on Pulmonary Hypertension in COPD

Pulmonary hypertension (PH) is a frequent and important complication of chronic obstructive pulmonary disease (COPD). It is associated with worse clinical courses with more frequent exacerbation episodes, shorter survival, and greater need of health resources. PH is usually of moderate severity and progresses slowly, without altering right ventricular function in the majority of cases. Nevertheless, a reduced subgroup of patients may present disproportionate PH, with pulmonary artery pressure (PAP) largely exceeding the severity of respiratory impairment. These patients may represent a group with an exaggerated vascular impairment (pulmonary vascular phenotype) to factors that induce PH in COPD or be patients in whom idiopathic pulmonary arterial hypertension (PAH) coexist. The present review addresses the current definition and classification of PH in COPD, the distinction among the different phenotypes of pulmonary vascular disease that might present in COPD patients, and the therapeutic approach to PH in COPD based on the available scientific evidence.

The hallmarks of severe pulmonary arterial hypertension: the cancer hypothesis-ten years later

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.

Clinical implications of partial anomalous pulmonary venous connection: a rare cause of severe pulmonary arterial hypertension

Isolated partial anomalous pulmonary venous connection (PAPVC) is an uncommon congenital heart anomaly that is sporadically associated with pulmonary arterial hypertension in the adult population. The diagnosis and therapy for this condition are challenging. We report on three cases of patients with unexpected severe precapillary pulmonary hypertension in single PAPVC treated with an upfront pulmonary arterial hypertension-specific combination therapy. Our cases indicate that the combination of PAPVC and pulmonary comorbidities may trigger the development of severe pulmonary arterial hypertension. The initiation of pulmonary arterial hypertension-targeted combination therapy revealed to be a safe and efficacious strategy for patients with PAPVC-associated severe pulmonary arterial hypertension.

The T helper type 17/regulatory T cell imbalance was associated with Ras-GTPase overexpression in patients with pulmonary hypertension associated with chronic obstructive pulmonary disease

Pulmonary hypertension (PH) is a common but dangerous complication in chronic obstructive pulmonary disease (COPD). We hypothesized that dysregulation in the T helper type 17 (Th17) compartment could contribute to the development of COPD-associated PH (COPD-PH). To investigate this hypothesis, patients with COPD-PH and age- and sex-matched healthy controls were recruited, and their circulating CD4⁺ T cells were activated using anti-CD3/CD28 antibodies. The frequency of interleukin-17 (IL-17) -secreting cells was significantly higher in COPD-PH patients than in healthy controls. The secretion of IL-17 was significantly higher from COPD-PH CD4⁺ T cells than from control CD4⁺ T cells, whereas the secretion of interferon-γ and IL-4 was not significantly different. The expression of transforming growth factor-β, on the other hand, was significantly higher in healthy controls than in COPD-PH patients. Activated CD4⁺ T cells from COPD-PH patients also presented significantly lower forkhead box P3 (FOXP3) and higher retinoic acid receptor-related orphan C2 (RORC2) expression than CD4⁺ T cells from healthy controls. In both controls and patients, a negative correlation between RORC2 and FOXP3 was found, ex vivo and after CD3/CD28 activation. The serum IL-6 level was slightly higher in COPD-PH patients than in controls, but the IL-6 transcription by monocytes was comparable in COPD-PH patients and controls. Interestingly, CD4⁺ T cells from COPD-PH patients presented significantly higher levels of Kirsten rat sarcoma viral oncogene homolog and neuroblastoma RAS viral oncogene homolog than CD4⁺ T cells from healthy controls. Inhibiting Ras-GTPases using farnesylthiosalicylic acid significantly reduced the ratio of RORC2/FOXP3 expression in CD4⁺ T cells. Overall, we demonstrated that an imbalance of Th17/regulatory T cells was a hallmark of COPD-PH.

Pulmonary Arterial Histologic Lesions in Patients With COPD With Severe Pulmonary Hypertension

BACKGROUND

The development of pulmonary hypertension (PH) during the course of COPD is a well-known phenomenon, with the prevalence depending on the severity of airway obstruction. When mean pulmonary pressure (mPAP) level at rest is ≥ 35 mm Hg or ≥ 25 mm Hg with low cardiac index, the term severe PH is used. For these patients, little is known on the underlying histologic lesions. Our objective was to describe these lesions.

METHODS

From the explants of patients undergoing lung transplantation, we compared retrospectively three groups of patients with COPD: severe PH-COPD (n = 10), moderate PH-COPD (mPAP between 25 and 34 mm Hg without low cardiac index) (n = 10), and no PH (mPAP < 25 mm Hg) (n = 10). Histologic analysis of the explanted lungs examined the wall of medium-size arteries, the remodeling of microvessels, and the pulmonary capillary density using morphometric measurements performed on three sections per patient.

RESULTS

Compared with the moderate PH group, the remodeling score of the microvessels was significantly higher (P = .0045) and the capillary density was lower (P = .0049) in the severe PH-COPD group. The alterations of the medium-size arteries, important in group 1 PH, seemed less discriminating.

CONCLUSIONS

Patients with severe PH-COPD appear to have a specific histologic pattern, different from that observed in patients with COPD with moderate PH or without PH.

Hypoxia-induced pulmonary hypertension and chronic lung disease: caveolin-1 dysfunction an important underlying feature

Caveolin-1 (cav-1) has been shown to play a significant role in the pathogenesis of pulmonary hypertension (PH). In the monocrotaline model of PH, the loss of endothelial cav-1 as well as reciprocal activation of proliferative and anti-apoptotic pathways initiate the disease process and facilitate its progression. In order to examine the role of cav-1 in hypoxia-induced PH, we exposed rats and neonatal calves to hypobaric hypoxia and obtained hemodynamic data and assessed the expression of cav-1 and related proteins eNOS, HSP90, PTEN, gp130, PY-STAT3, β-catenin, and Glut1 in the lung tissue. Chronic hypoxic exposure in rats (48 h-4 weeks) and calves (two weeks) did not alter the expression of cav-1, HSP90, or eNOS. PTEN expression was significantly decreased accompanied by PY-STAT3 activation and increased expression of gp130, Glut1, and β-catenin in hypoxic animals. We also examined cav-1 expression in the lung sections from steers with chronic hypoxic disease (Brisket disease) and from patients with chronic lung disease who underwent lung biopsy for medical reasons. There was no cav-1 loss in Brisket disease. In chronic lung disease cases, endothelial cav-1 expression was present, albeit with less intense staining in some cases. In conclusion, hypoxia did not alter the cav-1 expression in experimental models. The presence of cav-1, however, did not suppress hypoxia-induced activation of PY-STAT3 and β catenin, increased gp130 and Glut1 expression, or prevent the PTEN loss, indicating cav-1 dysfunction in hypoxia-induced PH.

Small Airway Disease in Pulmonary Hypertension-Additional Diagnostic Value of Multiple Breath Washout and Impulse Oscillometry

Airways obstruction is frequent in patients with pulmonary hypertension (PH). Small airway disease (SAD) was identified as a major contributor to resistance and symptoms. However, it is easily missed using current diagnostic approaches. We aimed to evaluate more elaborate diagnostic tests such as impulse oscillometry (IOS) and SF₆-multiple-breath-washout (MBW) for the assessment of SAD in PH. Twenty-five PH patients undergoing body-plethysmography, IOS and MBW testing were prospectively included and equally matched to pulmonary healthy and non-healthy controls. Lung clearance index (LCI) and acinar ventilation heterogeneity (S_acin) differed significantly between PH, healthy and non-healthy controls. Likewise, differences were found for all IOS parameters between PH and healthy, but not non-healthy controls. Transfer factor corrected for ventilated alveolar volume (TLCO/VA), frequency dependency of resistance (D5-20), resonance frequency (F_res) and S_acin allowed complete differentiation between PH and healthy controls (AUC (area under the curve) = 1.0). Likewise, PH patients were separated from non-healthy controls (AUC 0.762) by D5-20, LCI and conductive ventilation heterogeneity (S_cond). Maximal expiratory flow (MEF) values were not associated with additional diagnostic values. MBW and IOS are feasible in PH patients both providing additional information. This can be used to discriminate PH from healthy and non-healthy controls. Therefore, further research targeting SAD in PH and evaluation of therapeutic implications is justified.

Role of SOD3 in silica-related lung fibrosis and pulmonary vascular remodeling

BACKGROUND

Work-place exposure to silica dust may lead to progressive lung inflammation culminating in the development of silicosis, an irreversible condition that can be complicated by onset of pulmonary hypertension (PH). The molecular mechanisms leading to the development of PH and lung fibrosis in response to silica are not well understood. Oxidant/antioxidant imbalance in the lung may promote fibroproliferation and vascular smooth muscle proliferation, ultimately leading to the development of PH. Herein, we analyze the development of PH and lung fibrosis in mice deficient in extracellular superoxide dismutase (SOD3), an enzyme with anti-oxidant activity.

METHODS

PH and silicosis were induced in wild-type and Sod3-/- mice through intratracheal injection of crystalline silica at dose 0.4 g/kg. Pulmonary hypertension and lung fibrosis were characterized by changes in right ventricular systolic pressure (RVSP) and collagen deposition 28 days following silica injections. Vascular remodeling was analyzed using immunohistochemistry and morphometric analysis. The expression of genes were analyzed using qRT-PCR and Western blot.

RESULTS

C57BL6 mice exposed to silica showed attenuated expression of Sod3 in the lung suggesting a protective role for Sod3. Consistent with this, Sod3-/- mice developed more severe fibrotic inflammatory nodules with increased collagen deposition. Furthermore, the expression of genes involved in tissue remodeling (Timp1), fibrotic lesion formation (Fsp1) and inflammatory response (Mcp1) were significantly elevated in Sod3-/- mice compared to Sod3+/+ mice treated with silica. Infiltration of neutrophils and activated macrophages into affected lung was significantly higher in Sod3 deficient mice. In addition, silica produced more profound effects on elevation of RVSP in Sod3-/- compared to wild-type littermate. Increase in RVSP was concomitant with hypertrophy of pulmonary arteries located in silicotic nodules of both mouse strains, however, vascular remodeling in unaffected areas of lung was detected only in Sod3-/- mice.

CONCLUSIONS

Our data suggest that Sod3 and extracellular oxidative stress may play an important role in the development of pneumoconiosis and pulmonary vascular remodeling following exposure to environmental and occupational silica.

Inhaled Treprostinil in Pulmonary Hypertension Associated with Lung Disease

PURPOSE

Pulmonary hypertension (PH) in the setting of parenchymal lung disease adversely affects quality of life and survival. However, PH-specific drugs may result in ventilation/perfusion imbalance and currently, there are no approved PH treatments for this patient population. In the present retrospective study, data from 22 patients with PH associated with lung disease treated with inhaled treprostinil (iTre) and followed up clinically for at least 3 months are presented.

METHODS

PH was defined by resting right heart catheterization as a mean pulmonary artery pressure (mPAP) ≥ 35 mmHg, or mPAP ≥ 25 mmHg associated with pulmonary vascular resistance ≥ 4 Woods Units. Follow-up evaluation was performed at the discretion of the attending physician.

RESULTS

From baseline to follow-up, we observed significant improvement in functional class (n = 22, functional class III-IV 82 vs. 59%, p = 0.041) and 6-min walk distance (n = 11, 243 ± 106 vs. 308 ± 109; p = 0.022), without a deleterious effect on resting peripheral oxygen saturation (n = 22, 92 ± 6 vs. 94 ± 4; p = 0.014). Most of the patients (86%, n = 19/22) were using long-term nasal supplemental oxygen at baseline. During follow-up, only one patient had increased supplemental oxygen requirement. The most common adverse events were cough, headache, and diarrhea. No severe adverse event was reported.

CONCLUSIONS

The results suggest that iTre is safe in patients with Group 3 PH and evidence of pulmonary vascular remodeling in terms of functional class, gas exchange, and exercise capacity. Additionally, iTre was well tolerated. The potential role of PH-specific drugs in Group 3 PH should be further assessed in larger prospective studies.

Potential benefit of bosentan therapy in borderline or less severe pulmonary hypertension secondary to idiopathic pulmonary fibrosis-an interim analysis of results from a prospective, single-center, randomized, parallel-group study

Background

No drugs have been approved for the treatment of patients with pulmonary hypertension (PH) secondary to idiopathic pulmonary fibrosis (IPF), particularly those with idiopathic honeycomb lung. This study was conducted to investigate the long-term efficacy and safety of bosentan for PH based on changes in prognosis and respiratory failure.

Methods

IPF patients with borderline or less severe PH and completely organized honeycomb lung were randomized (1:1) to bosentan or no treatment for PH for 2 years and assessed at baseline and every 6 months for respiratory failure, activities of daily living (ADL), lung and heart functions by right cardiac catheterization, and other parameters. An interim analysis was performed, however, following detection of a significant survival benefit favoring bosentan therapy.

Results

Significant differences were noted for the bosentan-treated (n = 12) vs. untreated (n = 12) groups in hospital-free survival (603.44 ± 50.074 days vs. 358.87 ± 68.65 days; hazard ratio [HR], 0.19; P = 0.017) and overall survival (671 days vs. 433.78 ± 66.98 days; HR, 0.10; P = 0.0082). Again, significant improvements were noted for the bosentan-treated group from baseline to month 6 or 12 in several indices in ADL, pulmonary circulation, and %DLCO. Without requiring O₂ inhalation, bosentan was associated with no increase but a trend toward a decrease in adverse events and an improvement in respiratory status.

Conclusions

Bosentan tended to improve prognosis and ADL without worsening respiratory failure in IPF patients with borderline or less severe PH and completely organized honeycomb lung alone.

Trial registration

This study was registered on December 18, 2010 with UMIN-CTR Clinical Trial as UMIN000004749 to investigate the long-term influence of bosentan on cardiac function, as well as its cardioprotective efficacy and safety, in patients with pulmonary hypertension secondary to concurrent COPD and IPF, respectively.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12890-017-0523-2) contains supplementary material, which is available to authorized users.

Pulmonary venous remodeling in COPD-pulmonary hypertension and idiopathic pulmonary arterial hypertension

Pulmonary vascular arterial remodeling is an integral and well-understood component of pulmonary hypertension (PH). In contrast, morphological alterations of pulmonary veins in PH are scarcely described. Explanted lungs (n = 101) from transplant recipients with advanced chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary arterial hypertension (IPAH) were analyzed for venous vascular involvement according to a pre-specified, semi-quantitative grading scheme, which categorizes the intensity of venous remodeling in three groups of incremental severity: venous hypertensive (VH) grade 0 = characterized by an absence of venous vascular remodeling; VH grade 1 = defined by a dominance of either arterialization or intimal fibrosis; and VH grade 2 = a substantial composite of arterialization and intimal fibrosis. Patients were grouped according to clinical and hemodynamic characteristics in three groups: COPD non-PH, COPD-PH, and IPAH, respectively. Histological specimens were examined by a cardiovascular pathologist blinded to clinical and hemodynamic data. Pathological alterations of pulmonary veins were present in all hemodynamic groups, with the following incidences of VH grade 0/1/2: 34/66/0% in COPD non-PH; 19/71/10% in COPD-PH; and 11/61/28% in IPAH. In COPD, explorative correlation analysis of venous remodeling suggested a modest positive correlation with systolic and mean pulmonary artery pressure (P = 0.032, respectively) and an inverse modest correlation with diffusion capacity for carbon monoxide (P = 0.027). In addition, venous remodeling correlated positively with the degree of arterial remodeling (P = 0.014). In COPD-PH and IPAH, advanced forms of pulmonary venous remodeling are present, emphasizing that the disease is not exclusively restricted to arterial lesions. In addition, venous remodeling may be related to the hemodynamic severity, but more rigorous analysis is required to clearly define potential relationships.

Pulmonary arterial wall disease in COPD and interstitial lung diseases candidates for lung transplantation

BACKGROUND

Pulmonary hypertension (PH) associated with lung disease has the worst prognosis of all types of PH. Pulmonary arterial vasculopathy is an early event in the natural history of chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). The present study characterized the alterations in the structure and function of the pulmonary arterial (PA) wall of COPD and ILD candidates for lung transplantation (LTx).

METHODS

A cohort of 73 patients, 63 pre-LTx (30 COPD, 33 ILD), and ten controls underwent simultaneous right heart catheterisation and intravascular ultrasound (IVUS). Total pulmonary resistance (TPR), capacitance (Cp), and the TPR-Cp relationship were assessed. PA stiffness and the relative area of wall thickness were estimated as pulse PA pressure/IVUS pulsatility and as [(external sectional area-intimal area)/external sectional area] × 100, respectively.

RESULTS

Twenty-seven percent of patients had pulmonary arterial wedge pressure > 15 mmHg and were not analyzed. PA stiffness and the area of wall thickness were increased in comparison with controls, even in patients without PH (p < 0.05). ILD patients showed a significant higher PA stiffness, and lower Cp beyond mean PA pressure (mPAP) and lower area of wall thickness than COPD patients (p < 0.05). TPR-Cp relationship was shifted downward left for ILD patients.

CONCLUSIONS

Significant increase of PA stiffness and area of wall thickness were present even in patients without PH and can make the diagnosis of pulmonary vasculopathy at a preclinical stage in PH-lung disease candidates for LTx. ILD patients showed the worst PA stiffness and Cp with respect to COPD.

Effect of azithromycin in combination with simvastatin in the treatment of chronic obstructive pulmonary disease complicated by pulmonary arterial hypertension

OBJECTIVE

To evaluate the effect of azithromycin in combination with simvastatin in the treatment of chronic obstructive pulmonary disease (COPD) complicated by pulmonary arterial hypertension.

METHODS

Eighty-six patients who developed COPD and pulmonary arterial hypertension and received treatment from August 2013 to October 2014 were selected and randomly divided into an observation group and a control group using random number table, 43 in each group. Patients in the control group were orally administrated 20 mg of simvastatin, once a day. Patients in the observation group took 0.25g of azithromycin enteric-coated tablets, once a day, besides simvastatin. The treatment course of both groups was six months. Blood gas analysis indexes, forced expiratory volume in first second (FEV₁), six minutes walking distance, dyspnea grade and blood lipid parameter were recorded and compared between the two groups.

RESULTS

Arterial partial pressure of oxygen (PaO₂) and arterial partial pressure of carbon dioxide (PaCO₂) of the observation group were (68.13±3.03) mmHg and (45.08±2.27) mmHg after treatment, respectively. In the control group, the values were (60.01±4.72) mmHg and (38.93±1.61) mmHg, respectively. The improvement amplitude of the observation group was superior to that of the control group (P<0.05). FEV₁, forced vital capacity (FVC) and 6-minutes walking distance of the observation group were (1.08±0.11) L, (2.1±0.2) L and (380.34 ± 31.28) m respectively after treatment, superior to the control group ((0.93±0.09) L, (1.7±0.1) L) and (302.79±29.74) m, and the difference had statistical significance (P<0.05). The levels of peripheral systolic blood pressure (PSBP) and peripheral diastolic blood pressure (PDBP) of patients in the observation group were both lower than those of the control group, and the difference had statistical significance (P<0.05).

CONCLUSION

Azithromycin in combination with simvastatin has definite effect in the treatment of COPD in combination with pulmonary arterial hypertension as it can significantly relieve ventilation disturbance, improve lung function, and decrease pulmonary arterial pressure. Hence it is worth clinical promotion.

The principal pathways involved in the in vivo modulation of hypoxic pulmonary vasoconstriction, pulmonary arterial remodelling and pulmonary hypertension

Hypoxic pulmonary vasoconstriction (HPV) serves to optimize ventilation-perfusion matching in focal hypoxia and thereby enhances pulmonary gas exchange. During global hypoxia, however, HPV induces general pulmonary vasoconstriction, which may lead to pulmonary hypertension (PH), impaired exercise capacity, right-heart failure and pulmonary oedema at high altitude. In chronic hypoxia, generalized HPV together with hypoxic pulmonary arterial remodelling, contribute to the development of PH. The present article reviews the principal pathways in the in vivo modulation of HPV, hypoxic pulmonary arterial remodelling and PH with primary focus on the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways. In summary, endothelin-1 and thromboxane A₂ may enhance, whereas nitric oxide and prostacyclin may moderate, HPV as well as hypoxic pulmonary arterial remodelling and PH. The production of prostacyclin seems to be coupled primarily to cyclooxygenase-1 in acute hypoxia, but to cyclooxygenase-2 in chronic hypoxia. The potential role of adenine nucleotides in modulating HPV is unclear, but warrants further study. Additional modulators of the pulmonary vascular responses to hypoxia may include angiotensin II, histamine, serotonin/5-hydroxytryptamine, leukotrienes and epoxyeicosatrienoic acids. Drugs targeting these pathways may reduce acute and/or chronic hypoxic PH. Endothelin receptor antagonists and phosphodiesterase-5 inhibitors may additionally improve exercise capacity in hypoxia. Importantly, the modulation of the pulmonary vascular responses to hypoxia varies between species and individuals, with hypoxic duration and age. The review also define how drugs targeting the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways may improve pulmonary haemodynamics, but also impair pulmonary gas exchange by interference with HPV in chronic lung diseases.

Pulmonary hypertension and vascular remodeling in mice exposed to crystalline silica

Background

Occupational and environmental exposure to crystalline silica may lead to the development of silicosis, which is characterized by inflammation and progressive fibrosis. A substantial number of patients diagnosed with silicosis develop pulmonary hypertension. Pulmonary hypertension associated with silicosis and with related restrictive lung diseases significantly reduces survival in affected subjects. An animal model of silicosis has been described previously however, the magnitude of vascular remodeling and hemodynamic effects of inhaled silica are largely unknown. Considering the importance of such information, this study investigated whether mice exposed to silica develop pulmonary hypertension and vascular remodeling.

Methods

C57BL6 mice were intratracheally injected with either saline or crystalline silica at doses 0.2 g/kg, 0.3 g/kg and 0.4 g/kg and then studied at day 28 post-exposure. Pulmonary hypertension was characterized by changes in right ventricular systolic pressure and lung histopathology.

Results

Mice exposed to saline showed normal lung histology and hemodynamic parameters while mice exposed to silica showed increased right ventricular systolic pressure and marked lung pathology characterized by a granulomatous inflammatory reaction and increased collagen deposition. Silica-exposed mice also showed signs of vascular remodeling with pulmonary artery muscularization, vascular occlusion, and medial thickening. The expression of pro-inflammatory genes such as TNF-α and MCP-1 was significantly upregulated as well as the expression of the pro-remodeling genes collagen type I, fibronectin and the metalloproteinases MMP-2 and TIMP-1. On the other hand, the expression of several vasculature specific genes involved in the regulation of endothelial function was significantly attenuated.

Conclusions

We characterized a new animal model of pulmonary hypertension secondary to pulmonary fibrosis induced by crystalline silica. Our data suggest that silica promotes the damage of the pulmonary vasculature through mechanisms that might involve endothelial dysfunction, inflammation, and vascular remodeling.

Challenges and opportunities in treating inflammation associated with pulmonary hypertension

INTRODUCTION

Inflammatory cells are present in the lungs from patients with many, if not all, forms of severe pulmonary hypertension.

AREAS COVERED

Historically the first inflammatory cell identified in the pulmonary vascular lesions was the mast cell. T and B lymphocytes, as well as macrophages, are present in and around the pulmonary arterioles and many patients have elevated blood levels of interleukin 1 and 6; some patients show elevated levels of leukotriene B4. An overlap between collagen-vascular disease-associated pulmonary arterial hypertension (PAH) and idiopathic PAH exists, yet only a few studies have been designed that evaluate the effect of anti-inflammatory treatments. Here we review the pertinent data that connect PAH and inflammation/autoimmune dysregulation and evaluate experimental models of severe PAH with an emphasis on the Sugen/athymic rat model of severe PAH. Expert commentary: We postulate that there are several inflammatory phenotypes and predict that there will be several anti-inflammatory treatment strategies for severe PAH.

Pulmonary hypertension in the elderly: a different disease?

Pulmonary hypertension (PH) is a haemodynamic syndrome defined by a mean pulmonary arterial pressure (mPAP) >25 mmHg determined by right heart catheterisation (RHC) [1, 2]. A lot of ­diseases fulfil this definition, but they differ widely between each other in respect to their pathophysiology, their haemodynamic characteristics, their clinical presentation, their natural prognosis and their potential therapeutic strategies. The current guidelines on PH diagnosis and management make the distinction between five groups of more than 200 causes of PH [2], but these diseases are very different from one another. In the current classification, the first group (group 1) represents a progressive vasculopathy leading to pre-capillary PH called pulmonary arterial hypertension (PAH), characterised by a characteristic small-calibre pulmonary artery remodelling, as a result of proliferation of endothelial and smooth muscle cells as well as medial hypertrophy. So, if we compare PAH (for example idiopathic PAH) from PH due to valvular disease like mitral insufficiency (group 2.3) it is easy to understand that apart from the fact that mean pulmonary arterial pressure (mPAP) exceeds 25 mmHg in both cases, these two entities have very different pathophysiological pathways. In the first case, there is a true pulmonary vasculopathy. In the second, PH is mainly related to the consequences of an increased hydrostatic pressure in the left atrium ­transmitted to the venous compartment of the pulmonary circulation and then back through the capillary bed. If the pathophysiology of these entities is different, the targets of their treatments are too. The main goal of PAH treatment consists in reducing pulmonary vascular resistance (PVR) with specific medication and, when appropriate, with specific treatment of the underlying disease as it is the case for associated-PAH (group 1.4). Alternatively, the management of PH related to a mitral regurgitation would be to improve the ventricular preload, diminish the ventricular afterload and, if necessary, to correct the anatomical anomaly.

The distinction between PH in the elderly and normal ageing might make diagnosis difficulthttp://ow.ly/YYF1Q

Pulmonary vasculature in COPD: The silent component

Chronic obstructive pulmonary disease (COPD) is characterized by airflow obstruction that results from an inflammatory process affecting the airways and lung parenchyma. Despite major abnormalities taking place in bronchial and alveolar structures, changes in pulmonary vessels also represent an important component of the disease. Alterations in vessel structure are highly prevalent and abnormalities in their function impair gas exchange and may result in pulmonary hypertension (PH), an important complication of the disease associated with reduced survival and worse clinical course. The prevalence of PH is high in COPD, particularly in advanced stages, although it remains of mild to moderate severity in the majority of cases. Endothelial dysfunction, with imbalance between vasodilator/vasoconstrictive mediators, is a key determinant of changes taking place in pulmonary vasculature in COPD. Cigarette smoke products may perturb endothelial cells and play a critical role in initiating vascular changes. The concurrence of inflammation, hypoxia and emphysema further contributes to vascular damage and to the development of PH. The use of drugs that target endothelium-dependent signalling pathways, currently employed in pulmonary arterial hypertension, is discouraged in COPD due to the lack of efficacy observed in randomized clinical trials and because there is compelling evidence indicating that these drugs may worsen pulmonary gas exchange. The subgroup of patients with severe PH should be ideally managed in centres with expertise in both PH and chronic lung diseases because alterations of pulmonary vasculature might resemble those observed in pulmonary arterial hypertension. Because this condition entails poor prognosis, it warrants specialist treatment.

Hypoxic pulmonary hypertension in chronic lung diseases: novel vasoconstrictor pathways

Pulmonary hypertension is a well recognised complication of chronic hypoxic lung diseases, which are among the most common causes of death and disability worldwide. Development of pulmonary hypertension independently predicts reduced life expectancy. In chronic obstructive pulmonary disease, long-term oxygen therapy ameliorates pulmonary hypertension and greatly improves survival, although the correction of alveolar hypoxia and pulmonary hypertension is only partial. Advances in understanding of the regulation of vascular smooth muscle tone show that chronic vasoconstriction plays a more important part in the pathogenesis of hypoxic pulmonary hypertension than previously thought, and that structural vascular changes contribute less. Trials of existing vasodilators show that pulmonary hypertension can be ameliorated and systemic oxygen delivery improved in carefully selected patients, although systemic hypotensive effects limit the doses used. Vasoconstrictor pathways that are selective for the pulmonary circulation can be blocked to reduce hypoxic pulmonary hypertension without causing systemic hypotension, and thus provide potential targets for novel therapeutic strategies.

Pulmonary hypertension associated with chronic obstructive lung disease and idiopathic pulmonary fibrosis

PURPOSE OF REVIEW

Severe pulmonary hypertension worsens the prognosis of patients with chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF). With the aim of better understanding the pathogenesis of this event and identifying the possible targets for therapeutic intervention, a great deal of clinical and translational research is now focused on this relevant field of medicine.

RECENT FINDINGS

Some studies that were published last year have helped to better define the clinical and physiological profiles of patients with COPD or IPF and severe pulmonary hypertension. The importance of pulmonary rehabilitation was confirmed, particularly in patients with pulmonary hypertension associated with IPF. Information on the use of drugs approved for the treatment of pulmonary arterial hypertension is still very limited, because of some limitations and selection biases in the studies' design. New strategies (i.e. the use of fasudil or sepiapterin in pulmonary hypertension associated with IPF) have been evaluated in animal models.

SUMMARY

Pulmonary hypertension in COPD or IPF may range from mild to severe. When pulmonary hypertension is more advanced, it can drive a poor outcome. Therefore, future studies should focus on this subset.

Potential Role of CT Metrics in Chronic Obstructive Pulmonary Disease with Pulmonary Hypertension

PURPOSE

Recent imaging studies demonstrated the usefulness of quantitative computed tomographic (CT) analysis assessing pulmonary hypertension (PH) in patients with chronic obstructive lung disease (COPD-PH). The aim of this study was to investigate whether it would be also valuable for predicting and evaluating the effect of pulmonary vasodilators in patients with COPD-PH.

METHODS

We analyzed a correlation between the extent of cystic destruction (LAA%) and total cross-sectional areas of small pulmonary vessels less than 5 mm(2) (%CSA <5) in many CT slices from each of four COPD-PH patients before and after the initiation of pulmonary vasodilator. To evaluate those generalized data from patients with COPD, we evaluated multiple slices from 42 patients whose PH was not clinically suspicious. We also selected five PH patients with idiopathic interstitial pneumonia (IIP-PH) and analyzed serial changes of pulmonary artery enlargement (PA:A ratio).

RESULTS

In 42 COPD patients without PH, LAA% had a statistically significant negative correlation with %CSA <5. However, three of four COPD-PH patients manifested no such correlation. In two patients, clinical findings were dramatically improved after the initiation of pulmonary vasodilator. Notably, LAA% and %CSA <5 in those patients correlated significantly after its treatment. In COPD-PH, the PA:A ratio was significantly decreased after the initiation of pulmonary vasodilator therapy (1.25 ± 0.13 vs. 1.13 ± 0.11, p = 0.019), but not in IIP-PH.

CONCLUSIONS

Our study demonstrates that the use of quantitative CT analysis is a plausible and beneficial tool for predicting and evaluating the effect of pulmonary vasodilators in patients with COPD-PH.