Mechanisms of pulmonary hypertension in chronic obstructive pulmonary disease: A pathophysiologic review

Traditional and Advanced Echocardiographic Evaluation in Chronic Obstructive Pulmonary Disease: The Forgotten Relation

Chronic obstructive pulmonary disease (COPD) is a significant preventable and treatable clinical disorder defined by a persistent, typically progressive airflow obstruction. This disease has a significant negative impact on mortality and morbidity worldwide. However, the complex interaction between the heart and lungs is usually underestimated, necessitating more attention to improve clinical outcomes and prognosis. Indeed, COPD significantly impacts ventricular function, right and left chamber architecture, tricuspid valve functionality, and pulmonary blood vessels. Accordingly, more emphasis should be paid to their diagnosis since cardiac alterations may occur very early before COPD progresses and generate pulmonary hypertension (PH). Echocardiography enables a quick, noninvasive, portable, and accurate assessment of such changes. Indeed, recent advancements in imaging technology have improved the characterization of the heart chambers and made it possible to investigate the association between a few cardiac function indexes and clinical and functional aspects of COPD. This review aims to describe the intricate relation between COPD and heart changes and provide basic and advanced echocardiographic methods to detect early right ventricular and left ventricular morphologic alterations and early systolic and diastolic dysfunction. In addition, it is crucial to comprehend the clinical and prognostic significance of functional tricuspid regurgitation in COPD and PH and the currently available transcatheter therapeutic approaches for its treatment. Moreover, it is also essential to assess noninvasively PH and pulmonary resistance in patients with COPD by applying new echocardiographic parameters. In conclusion, echocardiography should be used more frequently in assessing patients with COPD because it may aid in discovering previously unrecognized heart abnormalities and selecting the most appropriate treatment to improve the patient's symptoms, quality of life, and survival.

Codonopsis Radix Inhibits the Inflammatory Response and Oxidative Stress in Chronic Obstructive Pulmonary Disease Mice through Regulation of the Nrf2/NF-κB Signaling Pathway

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a nonspecific chronic inflammatory lung disease with no known cure. Codonopsis Radix (CR) has been shown to exhibit anti-inflammatory and antioxidant effects. Therefore, this study aimed to investigate the potential anti-inflammatory effects of different CR varieties on COPD mice.

METHODS

Sixty male-specified pathogen-free grade C57BL/6J mice were randomly divided into 6 groups, 10 mice in each group. The COPD mice model was induced by cigarette smoke extract combined with lipopolysaccharide, and the mice in each group were given corresponding drugs. Lung function was assessed in all mice. Lung tissues were stained with hematoxylin-eosin, Masson, and periodic acid-Schiff stains, and serum levels of interleukin (IL)-8 and tumor necrosis factor (TNF)-α were detected using an ELISA. Further, serum and lung tissue levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were detected by colorimetric assay. Network pharmacology and molecular docking were used to predict signaling pathways, which were validated by Western blot analysis.

RESULTS

Compared with the COPD group, the mice in each dosing group of CR exhibited significant reductions in serum IL-8 and TNF-α levels, serum and lung tissue MDA levels, and pathological lung tissue damage, alongside elevations in lung function and SOD levels (p < 0.01). Western blot analysis also indicated significant downregulation of p-p65/p65 and p-IκB-α/IκB-α protein expression, alongside significant upregulation of Nrf2 protein expression in the lung tissues of mice treated with CR (p < 0.01).

CONCLUSION

In summary, CR effectively enhances lung function, minimizes lung tissue damage, and inhibits inflammation and oxidative stress in mice with COPD. Additionally, these findings suggest that inhibition of the Nrf2/NF-κB axis may be a key mechanism of action of CR in the alleviation of COPD.

Diagnostic Value of Galectin-3 in Exacerbations of Chronic Obstructive Pulmonary Disease

Background and Objectives: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterized by acute exacerbations. Systemic inflammation and oxidative stress play an important role in the pathogenesis of COPD. Exacerbations in COPD reduce the quality of life and are associated with rapid disease progression. Galectin-3 is a beta-galactoside-binding lectin of approximately 30 kDa with pro-inflammatory and pro-fibrotic properties. This study aims to analyze the efficacy of serum galectin-3 in predicting exacerbations in COPD patients. Materials and Methods: Baseline demographic and clinical characteristics of all patients were recorded and blood samples were collected. A total of 58 consecutive COPD patients, including 28 patients (19 male and 9 female) with stable COPD and 30 patients (23 male and 7 female) with acute exacerbation of COPD (AECOPD), were included in the study. Results: Serum galectin-3 levels were significantly higher in the AECOPD group compared to the stable COPD group. A logistic regression analysis revealed that increased galectin-3 levels and disease duration were independent predictors of COPD exacerbation (OR = 5.322, 95% CI: 1.178-24.052, p = 0.03; and OR = 1.297, 95% CI: 1.028-1.635, p = 0.028; respectively). Conclusions: The results of our study demonstrated that Galectin-3 was a strong and independent predictor of exacerbations in COPD patients.

Assessment and diagnosis of right ventricular failure-retrospection and future directions

The right ventricle (RV) has a critical role in hemodynamics and right ventricular failure (RVF) often leads to poor clinical outcome. Despite the clinical importance of RVF, its definition and recognition currently rely on patients' symptoms and signs, rather than on objective parameters from quantifying RV dimensions and function. A key challenge is the geometrical complexity of the RV, which often makes it difficult to assess RV function accurately. There are several assessment modalities currently utilized in the clinical settings. Each diagnostic investigation has both advantages and limitations according to its characteristics. The purpose of this review is to reflect on the current diagnostic tools, consider the potential technological advancements and propose how to improve the assessment of right ventricular failure. Advanced technique such as automatic evaluation with artificial intelligence and 3-dimensional assessment for the complex RV structure has a potential to improve RV assessment by increasing accuracy and reproducibility of the measurements. Further, noninvasive assessments for RV-pulmonary artery coupling and right and left ventricular interaction are also warranted to overcome the load-related limitations for the accurate evaluation of RV contractile function. Future studies to cross-validate the advanced technologies in various populations are required.

Pharmacology and Emerging Therapies for Group 3 Pulmonary Hypertension Due to Chronic Lung Disease

Pulmonary hypertension (PH) frequently complicates chronic lung disease and is associated with high morbidity and poor outcomes. Individuals with interstitial lung disease and chronic obstructive pulmonary disease develop PH due to structural changes associated with the destruction of lung parenchyma and vasculature with concurrent vasoconstriction and pulmonary vascular remodeling similar to what is observed in idiopathic pulmonary arterial hypertension (PAH). Treatment for PH due to chronic lung disease is largely supportive and therapies specific to PAH have had minimal success in this population with exception of the recently FDA-approved inhaled prostacyclin analogue treprostinil. Given the significant disease burden of PH due to chronic lung diseases and its associated mortality, a great need exists for improved understanding of molecular mechanisms leading to vascular remodeling in this population. This review will discuss the current understanding of pathophysiology and emerging therapeutic targets and potential pharmaceuticals.

Natural therapeutics and nutraceuticals for lung diseases: Traditional significance, phytochemistry, and pharmacology

BACKGROUND

Lung diseases including chronic obstructive pulmonary disease (COPD), infections like influenza, acute respiratory distress syndrome (ARDS), asthma and pneumonia lung cancer (LC) are common causes of sickness and death worldwide due to their remoteness, cold and harsh climatic conditions, and inaccessible health care facilities.

PURPOSE

Many drugs have already been proposed for the treatment of lung diseases. Few of them are in clinical trials and have the potential to cure infectious diseases. Plant extracts or herbal products have been extensively used as Traditional Chinese Medicine (TCM) and Indian Ayurveda. Moreover, it has been involved in the inhibition of certain genes/protiens effects to promote regulation of signaling pathways. Natural remedies have been scientifically proven with remarkable bioactivities and are considered a cheap and safe source for lung disease.

METHODS

This comprehensive review highlighted the literature about traditional plants and their metabolites with their applications for the treatment of lung diseases through experimental models in humans. Natural drugs information and mode of mechanism have been studied through the literature retrieved by Google Scholar, ScienceDirect, SciFinder, Scopus and Medline PubMed resources against lung diseases.

RESULTS

In vitro, in vivo and computational studies have been explained for natural metabolites derived from plants (like flavonoids, alkaloids, and terpenoids) against different types of lung diseases. Probiotics have also been biologically active therapeutics against cancer, anti-inflammation, antiplatelet, antiviral, and antioxidants associated with lung diseases.

CONCLUSION

The results of the mentioned natural metabolites repurposed for different lung diseases especially for SARS-CoV-2 should be evaluated more by advance computational applications, experimental models in the biological system, also need to be validated by clinical trials so that we may be able to retrieve potential drugs for most challenging lung diseases especially SARS-CoV-2.

Traffic-related air pollution associated pulmonary pathophysiologic changes and cardiac injury in elderly patients with COPD

Traffic-related air pollution (TRAP) has shown enormous environmental toxicity, but its cardiorespiratory health impact on chronic obstructive pulmonary disease (COPD) has been less studied. We followed a panel of 45 COPD patients with 4 repeated clinical visits across 14 months in a traffic-predominated urban area of Beijing, China, with concurrent measurements of TRAP metrics (fine particulate matter, black carbon, oxides of nitrogen and carbon monoxide). Linear mixed-effect models were performed to evaluate the associations and potential pathways linking traffic pollution to indicators of spirometry, cardiac injury, inflammation and oxidative stress. We observed that interquartile range increases in moving averages of TRAP exposures at prior up to 7 days were associated with significant reductions in large and small airway functions, namely decreases in forced vital capacity of 3.1-9.3% and forced expiratory flow 25-75% of 5.9-16.4%. Higher TRAP levels were also associated with worsening of biomarkers relevant to lung injury (hepatocyte growth factor and surfactant protein D) and cardiac injury (high-sensitivity cardiac troponin I, B-type natriuretic peptide and soluble ST2), as well as enhanced airway/systemic inflammation and oxidative stress. Mediation analyses showed that TRAP exposures may prompt cardiac injury, possibly via worsening pulmonary pathophysiology. These findings highlight the importance of traffic pollution control priority in urban areas.

Arterial partial pressure of oxygen and procalcitonin levels correlate with pulmonary artery systolic pressure in patients with active pulmonary tuberculosis

OBJECT

We aimed to study whether arterial blood gas parameters, inflammatory markers, and coagulation indicators correlate with pulmonary artery systolic pressure (PASP) values in patients with active pulmonary tuberculosis (PTB).

METHODS

A total of 121 patients with PTB who had a measurement of PASP by Doppler echocardiography in the active phase of tuberculosis were included in this study. We carried out univariate and multivariate linear regression analyses to determine factors correlated with PASP values. We excluded patients with other diseases or conditions that might lead to increased PASP.

RESULTS

Univariate linear regression analysis revealed positive correlations of age, white blood cell count, neutrophils ratio, Log procalcitonin, erythrocyte sedimentation rate, Log C-reactive protein, fibrinogen, Log D-dimer with PASP and showed an inverse correlation of arterial partial pressure of oxygen (PaO₂) and arterial oxygen saturation (SaO₂) with PASP. Multiple linear regression analysis demonstrated that PaO₂ and Log procalcitonin remained correlated with PASP values.

CONCLUSION

PaO₂ and procalcitonin were strongly correlated with PASP values in patients with active PTB. The degree of hypoxia and severity of secondary respiratory bacterial infection may influence PASP value in active PTB.

NT-pro BNP in AECOPD-PH: old biomarker, new insights-based on a large retrospective case-controlled study

Background

Pulmonary hypertension (PH) is one of the common complications in chronic obstructive pulmonary disease (COPD). The study aimed to evaluate the predicting ability of N-terminal pro brain natriuretic peptide (NT-pro BNP) in patients with AECOPD-PH and its relationship with the severity of PH.

Methods

A large retrospective case-controlled study (n = 1072) was performed in the First Affiliated Hospital of Xinjiang Medical University from January 2018 to December 2020, and patients were divided into stable COPD (n = 178), AECOPD (n = 688) and AECOPD-PH group (n = 206). Different statistical models were used to screen for reliable and stable biomarkers.

Results

In unadjusted analysis and PSM (model 1, 2, 3), red cell distribution width (RDW), total bilirubin (TBIL), and NT-pro BNP were higher in patients with AECOPD-PH than those in AECOPD group. Logistic regression analysis showed, when the range of NT-proBNP was 271–1165 pg/mL (OR: 0.293; 95%CI: 0.184–0.467; P < 0.001) and NT-proBNP > 1165 pg/mL (OR: 0.559; 95%CI: 0.338–0.926; P = 0.024), the morbidity risk of PH in AECOPD patients was increased, so did TBIL. In receiver operating characteristic (ROC) curves, at the cut-off value of NT-proBNP was 175.14 pg/mL, AUC was 0.651 (P < 0.001), which was better than TBIL (AUC: 0.590, P < 0.001). As for the results of rank correlation analysis, NT-proBNP had a weak correlation with severity of PH with AECOPD (r_s = 0.299, P = 0.001) and its relative relevance with other biomarkers (RDW was 0.359 and TBIL was 0.238, P < 0.001).

Conclusions

Our findings suggest that NT-proBNP has a diagnostic efficacy in AECOPD-PH and NT-proBNP has a weak correlation with severity of PH with AECOPD.

Right ventricular failure: a comorbidity or a clinical emergency?

There has been ample data providing a convincing perception about the underlying mechanism pertaining to left ventricle (LV) hypertrophy progressing towards LV failure. In comparison, data available on the feedback of right ventricle (RV) due to volume or pressure overload is minimal. Advanced imaging techniques have aided the study of physiology, anatomy, and diseased state of RV. However, the treatment scenario of right ventricular failure (RVF) demands more attention. It is a critical clinical risk in patients with carcinoid syndrome, pulmonary hypertension, atrial septal defect, and several other concomitant diseases. Although the remodeling responses of both ventricles on an increase of end-diastolic pressure are mostly identical, the stressed RV becomes more prone to oxidative stress activating the apoptotic mechanism with diminished angiogenesis. This instigates the advancement of RV towards failure in contrast to LV. Empirical heart failure (HF) therapies have been ineffective in improving the mortality rate and cardiac function in patients, which prompted a difference between the underlying pathophysiology of RVF and LV failure. Treatment strategies should be devised, taking into consideration the anatomical and physiological characteristics of RV. This review would emphasize on the pathophysiology of the RVF and the differences between two ventricles in molecular response to stress. A proper insight into the underlying pathophysiology is required to develop optimized therapeutic management in RV-specific HF.

Main pulmonary artery enlargement predicts 90-day readmissions in Chinese COPD patients

Background

Numerous studies have shown pulmonary artery enlargement when measured by chest computed tomography (CT) could predict a worse outcome in chronic obstructive pulmonary disease (COPD) patients. Herein, we studied the prognostic implication of main pulmonary artery diameter (MPAD) in Chinese COPD patients.

Methods

This is an observational case-control study. Patients with 90-day readmissions are case group and those without 90-day readmission are control group. The study comprised of 417 COPD patients who underwent chest CT in their initial admission due to acute exacerbation of COPD (AECOPD). We analyzed their clinical characteristics such as MPAD, arterial blood gas (ABG) results, other chest CT findings and comorbidities to identify the cause of readmission within 90 days.

Results

Median age of our study population is 75 years old, and 79.6% of them are male. The median MPAD is 2.8 cm and 80.6% were also diagnosed with community acquired pneumonia (CAP) in their first admission. The median MPAD in patients with 90-day readmission was 3.1 cm while patients without 90-day readmission had median MPAD of 2.8 cm. Through multivariate logistic regression analysis CAP (P=0.019, OR: 3.105, 95% CI: 1.203-8.019) and MPAD (P<0.001, OR: 2.898, 95% CI: 1.824-4.605) were statistically significant. In the second stage of analysis, subgroup of patients diagnosed with CAP and AECOPD (pAECOPD) were analyzed, MPAD remained statistically significant (P<0.001, OR: 3.490, 95% CI: 1.929-6.316) and receiver operative characteristic (ROC) curve for pAECOPD patients; area under the curve (AUC) was 0.704 (95% CI: 0.631-0.778) with a MPAD cut off value of 2.9 cm (sensitivity 72%, specificity 53%).

Conclusions

Enlarged MPAD and pAECOPD in initial admission are independent risk factors for 90-day readmission. In our pAECOPD patient population, MPAD >2.9 cm are at increased risk of 90-day readmission.

Fengbaisan suppresses endoplasmic reticulum stress by up-regulating SIRT1 expression to protect rats with chronic obstructive pulmonary diseases

CONTEXT

Our previous study found that Fengbaisan improved chronic obstructive pulmonary diseases (COPD).

OBJECTIVE

To elucidate the mechanism of Fengbaisan in COPD.

MATERIALS AND METHODS

Rats in Model, FBS, FBS + DMSO and FBS + EX527 groups received cigarette smoke extract (CSE) inhalation and intratracheal instillation of lipopolysaccharide to establish COPD model. Normal group received room air and normal saline. The COPD rats were given Fengbaisan (1 mL/d) or combined with EX527 (5 mg/kg/2 d) by intraperitoneal injection. Human lung carcinoma (A549) cells were treated with 10% CSE, 10% serum-containing Fengbaisan or EX527. We observed lung percentage of forced expiratory volume in first 0.3 sec to forced vital capacity (FEV0.3/FVC), inspiratory resistance (RI) and lung dynamic compliance (Cdyn) of rats. The lung pathological changes, the number of inflammatory cells and neutrophils, inflammatory factor, apoptosis, gene and protein expression were examined.

RESULTS

SIRT1 was downregulated in lung tissues of COPD rats and CSE-induced A549 cells. Fengbaisan enhanced FEV0.3/FVC (74.28%) and Cdyn (0.28 cm H₂O/mL/s), and reduced RI (0.48 mL/cm H₂O) of COPD rats. Moreover, Fengbaisan promoted SIRT1 expression, and repressed TIMP-1/MMP-9 expression. Fengbaisan enhanced apoptosis and the expression of GRP78, caspase-12 and caspase-3. The inflammatory factor levels, the number of inflammatory cells and neutrophils, and lung lesions were inhibited by Fengbaisan in COPD rats. The influence conferred by Fengbaisan was abolished by EX527.

DISCUSSION AND CONCLUSIONS

Fengbaisan inhibits endoplasmic reticulum stress and inflammation reaction by up-regulating SIRT1 expression to improve COPD. Therefore, Fengbaisan may be an effective Chinese medicine for treating COPD.

Objective quantitative multidetector computed tomography assessments in patients with combined pulmonary fibrosis with emphysema: Relationship with pulmonary function and clinical events

BACKGROUND

Combined pulmonary fibrosis with emphysema (CPFE) is a clinically meaningful syndrome characterized by coexisting upper-lobe emphysema and lower-lobe interstitial fibrosis. However, ambiguous diagnostic criteria and, particularly, the absence of objective methods to quantify emphysematous/fibrotic lesions in patients with CPFE confound the interpretation of the pathophysiology of this syndrome. We analyzed the relationship between objectively quantified computed tomography (CT) measurements and the results of pulmonary function testing (PFT) and clinical events in CPFE patients.

MATERIALS AND METHODS

We enrolled 46 CPFE patients who underwent CT and PFT. The extent of emphysematous lesions was obtained by calculating the percent of low attenuation area (%LAA). The extent of fibrotic lesions was calculated as the percent of high attenuation area (%HAA). %LAA and %HAA values were combined to yield the percent of abnormal area (%AA). We assessed the relationships between CT parameters and other clinical indices, including PFT results. Multivariate analysis was performed to examine the association between the CT parameters and clinical events.

RESULTS

A greater negative correlation with percent predicted diffusing capacity of the lung for carbon monoxide (DLCO %predicted) existed for %AA (r = -0.73, p < 0.001) than for %LAA or %HAA alone. The %HAA value was inversely correlated with percent predicted forced vital capacity (r = -0.48, p < 0.001), percent predicted total lung capacity (r = -0.48, p < 0.01), and DLCO %predicted (r = -0.47, p < 0.01). Multivariate logistic regression analysis found that %AA showed the strongest association with hospitalization events (odds ratio = 1.20, 95% confidence interval = 1.01-1.54, p = 0.029).

CONCLUSION

Quantitative CT measurements reflected deterioration in pulmonary function and were associated with hospitalization in patients with CPFE. This approach could serve as a useful method to determine the extent of lung morphology, pathophysiology, and the clinical course of patients with CPFE.

Lung function in relation to six-minute walk test in pulmonary hypertension

Background: Pulmonary hypertension (PH) is a progressive disorder of the pulmonary circulation, associated with diverse medical conditions. Exercise limitation is the most prominent symptom in PH. Exercise capacity, commonly assessed through a six-minute walk test (6MWT), correlates with both functional status and survival in PH. Few studies have analysed the relation between respiratory function and exercise limitation. Therefore, we investigated the relationship between resting pulmonary function, exercise capacity, and exertional desaturation, assessed through the 6MWT, in unselected PH patients.

Methods: Fifty consecutive patients with PH diagnosis, referred for pulmonary function testing (lung volume, spirometry, and diffusing capacity for carbon monoxide (DLCO)) and 6MWT, were recruited at Molinette University Hospital, Turin.

Results: The majority of the patients (54%) had PH due to left heart disease. Airway obstruction (FEV₁/VC-ratio < 0.7) was found in 46% of the patients and they performed significantly worse in the 6MWT than unobstructed patients (307 m vs. 377 m). Patients with PH due to left heart disease also performed significantly poorer 6MWT when airway obstruction was present (305 m vs. 389 m). Twenty-two patients (44%) presented exertional desaturation upon 6MWT. Lower DLCO divided by the alveolar volume (DLCO/VA), FEV₁/VC-ratios and resting PaO₂-values were significantly correlated with exertional desaturation after adjustments for age, sex, BMI, and smoking habits. DLCO/VA was the main determinant of exertional desaturation in a stepwise regression model.

Conclusions: Spirometric parameters of airway obstruction were related to walk distance and exercise-induced desaturation in PH patients. This suggests a place for spirometry in clinical monitoring of PH patients.

Healthcare utilization, medical expenditure, and mortality in Korean patients with pulmonary hypertension

Background

Limited data exists regarding healthcare utilization, medical expenses, and prognosis of pulmonary hypertension (PH) according to the World Health Organization (WHO) classification. We aimed to investigate mortality risk, healthcare utilization and medical expenditure in patients with PH across the five diagnostic subgroups.

Methods

We identified 2185 patients with PH, defined as peak tricuspid regurgitation velocity > 3.4 m/sec, among the consecutive patients referred for echocardiography between 2009 and 2015. Using diagnostic codes, medical records, and echocardiographic findings, the enrolled patients were classified according to the five subgroups by WHO classification. Healthcare utilization, costs, and all-cause mortality were assessed.

Results

Diagnostic subgroups of PH demonstrated significantly different clinical features. During a median of 32.4 months (interquartile range, 16.2–57.8), 749 patients (34.3%) died. Mortality risk was the lowest in group II (left heart disease) and highest in group III (chronic lung disease). The etiologies of pulmonary arterial hypertension (PAH) had significant influence on the mortality risk in group I, showing the worst prognosis in PAH associated with connective tissue disease. Medical expenditure and healthcare utilization were different between the PH subgroups: groups II and V had more hospitalizations and medical expenses than other groups. Regardless of PH subgroups, the severity of PH was associated with higher mortality risk, more healthcare utilization and medical expenditure.

Conclusions

Significant differences in clinical features and prognostic profiles between PH subgroups reflect the differences in pathophysiology and clinical consequences. Our findings highlight the importance of comprehensive understanding of PH according to the etiology and its severity.

Right Ventricular Failure: Pathophysiology, Diagnosis and Treatment

The prognostic significance of the right ventricle (RV) has recently been recognised in several conditions, primarily those involving the left ventricle, the lungs and their vascular bed, or the right-sided chambers. Recent advances in imaging techniques have created new opportunities to study RV anatomy, physiology and pathophysiology, and contemporary research efforts have opened the doors to new treatment possibilities. Nevertheless, the treatment of RV failure remains challenging. Optimal management should consider the anatomical and physiological particularities of the RV and include appropriate imaging techniques to understand the underlying pathophysiological mechanisms. Treatment should include rapid optimisation of volume status, restoration of perfusion pressure and improvement of myocardial contractility and rhythm, and, in case of refractory RV failure, mechanical circulatory support.

Complement alternative pathway activation associated with pulmonary hypertension in lupus nephritis patients

Pulmonary hypertension occurs in systemic lupus erythematosus (SLE) for several reasons, such as vasculopathy. Previous studies have indicated that the excessive activation of the complement alternative pathway might be involved in the pathogenesis of lupus nephritis, especially in the absence of factor H or its functional impairment. However, the clinical and pathological significance of the alternative complement activation in lupus nephritis patients with pulmonary hypertension remains elusive. The data on patients with pulmonary hypertension and non-pulmonary hypertension lupus nephritis were retrospectively analyzed in our centre. Major plasma levels of complement components were evaluated. The depositions of Bb, C3d and C5b-9 in the lung specimens of pulmonary hypertension combined with SLE patients were detected by immunofluorescence staining. Among 352 lupus nephritis cases, 24 were diagnosed with pulmonary hypertension and 328 with non-pulmonary hypertension. Higher levels of Bb and lower levels of factor H were detected in the pulmonary hypertension group in comparison with the negative group (P = 0.049, P = 0.024, respectively). Pulmonary hypertension was a risk factor for renal outcome as deduced by the log-rank and Cox test for survival analysis. C3d, C5b-9 and Bb were found to be positive in lung specimens of lupus nephritis patients with pulmonary hypertension. We concluded that activation of the complement alternative pathway may be involved in the pathogenesis of pulmonary hypertension in lupus nephritis.

Bioinformatics-based study to detect chemical compounds that show potential as treatments for pulmonary thromboembolism

The objectives of the present study comprised the recognition of major genes related to pulmonary thromboembolism (PTE) and the evaluation of their functional enrichment levels, in addition to the identification of small chemical molecules that may offer potential for use in PTE treatment. The RNA expression profiling of GSE84738 was obtained from the Gene Expression Omnibus database. Following data preprocessing, the differently expressed genes (DEGs) between the PTE group and the control group were identified using the Linear Models for Microarray package. Subsequently, the protein‑protein interaction (PPI) network of these DEGs was examined using the Search Tool for the Retrieval of Interacting Genes/Proteins database, visualized via Cytoscape. The most significantly clustered modules in the network were identified using Multi Contrast Delayed Enhancement, a plugin of Cytoscape. Subsequently, functional enrichment analysis of the DEGs was performed, using the Database for Annotation Visualization and Integrated Discovery tool. Furthermore, the chemical‑target interaction networks were investigated using the Comparative Toxicogenomics Database as visualized via Cytoscape. A total of 548 DEGs (262 upregulated and 286 downregulated) were identified in the PTE group, compared with the control group. The upregulated and downregulated genes were enriched in Gene Ontology terms related to inflammation and eye sarcolemma, respectively. Tumor necrosis factor (TNF) and erb‑b2 receptor tyrosine kinase 2 (ERBB2) were upregulated genes that ranked higher in the PPI network (47 and 40 degrees, respectively) whereas C‑JUN was the most downregulated gene (46). Small chemical molecules ethinyl (135), cyclosporine (126), thrombomodulin precursor (113) and tretinoin (111) had >100 degrees in the DEG‑chemical interaction network. In addition, ethinyl targeted to TNF, whereas TNF and ERBB2 were targeted by cyclosporine, and tretinoin was a targeted chemical of ERBB2. Therefore, cyclosporine, ethinyl, and tretinoin may be potential targets for PTE treatment.

Pulmonary hypertension in chronic obstructive pulmonary disease and emphysema patients: prevalence, therapeutic options and pulmonary circulatory effects of lung volume reduction surgery

The exact prevalence of pulmonary hypertension (PH) and cor pulmonale (CP) in chronic obstructive pulmonary disease (COPD) is unknown, and varies considerably from 20-91%. Usually, mean pulmonary artery pressure (mPAP) does not exceed 30 mmHg, and PH is not severe. However, PH and CP are important predictors of mortality in COPD and contribute to disability in this disease. Many factors contribute to the development of PH in chronic lung disease, including reduction of the pulmonary vascular cross-sectional area due to parenchymal loss and accompanying hypoxia, effects of abnormal pulmonary mechanics due to hyperinflation, but also vascular remodeling processes. So far, PH associated with chronic lung disease cannot be treated medically. Therefore, it is indicated to treat the underlying pulmonary disease. Patients with severe PH should be referred to centers experienced in the management of PH and enrollment in clinical trials should be considered. Lung volume reduction surgery (LVRS) theoretically further increases pulmonary vascular resistance (PVR) by reducing the vascular bed when resecting lung tissue, however, this might be compensated by better pulmonary mechanics through reduction of hyperinflation, which will be discussed in the present article.

Recent developments in 3-D reconstruction and stereology to study the pulmonary vasculature

Alterations of the pulmonary vasculature are an important feature of human lung diseases such as chronic obstructive pulmonary disease, pulmonary hypertension, and bronchopulmonary dysplasia. Experimental studies to investigate the pathogenesis or a therapeutic intervention in animal models of these diseases often require robust, meaningful, and efficient morphometric data that allow for appropriate statistical testing. The gold standard for obtaining such data is design-based stereology. However, certain morphological characteristics of the pulmonary vasculature make the implementation of stereological methods challenging. For example, the alveolar capillary network functions according to the sheet flow principle, thus making unbiased length estimations impossible and requiring other strategies to obtain mechanistic morphometric data. Another example is the location of pathological changes along the branches of the vascular tree. For developmental defects like in bronchopulmonary dysplasia or for pulmonary hypertension, it is important to know whether certain segments of the vascular tree are preferentially altered. This cannot be overcome by traditional stereological methods but requires the combination of a three-dimensional data set and stereology. The present review aims at highlighting the great potential while discussing the major challenges (such as time consumption and data volume) of this combined approach. We hope to raise interest in the potential of this approach and thus stimulate solutions to overcome the existing challenges.

The association of neuron-derived orphan receptor 1 with pulmonary vascular remodeling in COPD patients

Introduction

Chronic hypoxia-induced pulmonary vascular remodeling is a feature of chronic obstructive pulmonary disease (COPD). Our previous reports indicate that neuron-derived orphan receptor 1 (NOR1) promoted pulmonary smooth muscle cell proliferation in vitro. But it remains unclear whether NOR1 participated into hypoxia-induced pulmonary vascular remodeling in COPD patients.

Patients and methods

For this study, we collected peripheral lung tissues of 26 male COPD patients with or without hypoxemia. We detected the pulmonary vascular remodeling in all the peripheral lung tissues. Primary human pulmonary arterial smooth muscle cells were also cultured in vitro and stimulated with hypoxia or normoxia. Cell proliferation and protein levels were detected.

Results

COPD patients with hypoxemia showed significantly enlarged pulmonary vessels wall thickness and increased protein levels of HIF-1α, smooth muscle actin, cyclin D1, and NOR1 when compared with those in normoxic patients. Moreover, hypoxia induced human pulmonary arterial smooth muscle cell proliferation and NOR1 overexpression in vitro. The plasmid-based NOR1 gene overexpression markedly promoted DNA synthesis and proliferation in hypoxia or normoxic cells. Human NOR1 gene-specific siRNA intensively suppressed DNA synthesis and proliferation. Transfection of NOR1 overexpression plasmid raised cyclin D1 protein levels, which could be significant inhibited by NOR1-specific siRNA or a CDK4/6 inhibitor PD0332991.

Conclusion

We concluded that NOR1 upregulation is associated with hypoxia-induced pulmonary vascular remodeling in COPD via promoting human pulmonary arterial smooth muscle cell proliferation.

Prognostic value of pre-transplant mean pulmonary arterial pressure in lung transplant recipients: a single-institution experience

Background

Currently, lung transplantation (LTX) is considered to be a curative treatment option in patients with end-stage lung disease. Although pulmonary hypertension (PH), confirmed by cardiac catheterization, is a prognostic factor in patients undergoing LTX, the prognostic value of PH in Asian lung transplant recipients remains uncertain. In this study, we aimed to determine whether PH before LTX may serve as a prognostic factor for survival in Asian patients.

Methods

The medical records of 50 patients [male, 27; female, 23; mean age, 51.0 (41.0-60.0) years], who received preoperative right heart catheterization (RHC) and echocardiography before single or double LTX at Severance Hospital between January 2010 and December 2014, were reviewed. The relationship between 1-year survival after LTX and PH [mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest] was evaluated.

Results

The mean right ventricular systolic pressure and mPAP were 48.5 (22.8) and 30.0 (24.0-40.0) mmHg. Of the 50 patients, 17 (34.0%) died within a year after LTX. The 1-year survival rate among patients with mPAP ≥25 mmHg (58.8%) was lower than the survival rate among patients with mPAP <25 mmHg (87.5%). Pre-transplantation mPAP of ≥25 mmHg was associated with post-transplantation survival [hazard ratio (HR), 4.832; 95% confidence interval (CI), 1.080-21.608, P=0.039]. The presence of preoperative PH was also associated with an increased risk of postoperative complications.

Conclusions

Confirmation of PH via preoperative cardiac catheterization was associated with the prognosis of the patient after LTX. Clinicians should consider the necessity for early transplantation surgery before the mPAP reaches ≥25 mmHg.

miR-190a-5p participates in the regulation of hypoxia-induced pulmonary hypertension by targeting KLF15 and can serve as a biomarker of diagnosis and prognosis in chronic obstructive pulmonary disease complicated with pulmonary hypertension

PURPOSE

miR-190a-5p expression alters dynamically in response to hypoxia. However, the role of miR-190a-5p expression in hypoxia-induced pulmonary hypertension (PH) remains unclear. We sought to correlate the miR-190a-5p expression levels with the severity, diagnosis, and prognosis of PH in relation to chronic obstructive pulmonary disease (COPD-PH). Additionally, we evaluated the effect of miR-190a-5p through in vitro experiments on human pulmonary endothelial cells (HPECs) that were exposed to hypoxia and in vivo experiments using an animal model of hypoxia-induced PH.

METHODS

Circulating miR-190a-5p levels were measured from 73 patients with PH and 32 healthy controls through quantitative real-time PCR. The levels of miR-190a-5p and the expression of Krüppel-like factor 15 (KLF15) were analyzed in HPECs that were exposed to hypoxia, and the effects of antagomir-190a-5p in mice with chronic hypoxia-induced PH were tested. Target gene analysis was performed by Western blot and luciferase assay.

RESULTS

The miR-190a-5p level was significantly higher in patients with COPD-PH than in the healthy controls. Higher miR-190a-5p levels were associated with a greater severity of COPD-PH. In vitro experiments on HPECs showed that exposure to hypoxia increased the miR-190a-5p levels significantly. KLF15 was validated as a target of miR-190a-5p. Transfection with miR-190a-5p mimicked inhibition of KLF15 expression in HPECs. In the mouse model of PH, antagomir-190a-5p reduced right ventricular systolic pressure and enhanced the KLF15 expression levels in lung tissue.

CONCLUSION

miR-190a-5p regulates hypoxia-induced PH by targeting KLF15. The circulating levels of miR-190a-5p correlate with the severity of COPD-PH, thereby confirming the diagnostic and prognostic value of this parameter in COPD-PH.

Hyperinflated lungs compress the heart during expiration in COPD patients: a new finding on dynamic-ventilation computed tomography

Purpose

The aims of this study were to evaluate dynamic changes in heart size during the respiratory cycle using four-dimensional computed tomography (CT) and to understand the relationship of these changes to airflow limitation in smokers.

Materials and methods

A total of 31 smokers, including 13 with COPD, underwent four-dimensional dynamic-ventilation CT during regular breathing. CT data were continuously reconstructed every 0.5 s, including maximum cross-sectional area (CSA) of the heart and mean lung density (MLD). Concordance between the cardiac CSA and MLD time curves was expressed by cross-correlation coefficients. The CT-based cardiothoracic ratio at inspiration and expiration was also calculated. Comparisons of the CT indices between COPD patients and non-COPD smokers were made using the Mann–Whitney test. Spearman rank correlation analysis was used to evaluate associations between CT indices and the forced expiratory volume in 1 s (FEV_1.0) relative to the forced vital capacity (FVC).

Results

Cardiac CSA at both inspiration and expiration was significantly smaller in COPD patients than in non-COPD smokers (P<0.05). The cross-correlation coefficient between cardiac CSA and MLD during expiration significantly correlated with FEV_1.0/FVC (ρ=0.63, P<0.001), suggesting that heart size decreases during expiration in COPD patients. The change in the cardiothoracic ratio between inspiration and expiration frames was significantly smaller in COPD patients than in non-COPD smokers (P<0.01).

Conclusion

Patients with COPD have smaller heart size on dynamic-ventilation CT than non-COPD smokers and have abnormal cardiac compression during expiration.

Risk factors for pulmonary arterial hypertension in patients with tuberculosis-destroyed lungs and their clinical characteristics compared with patients with chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

There are limited data on pulmonary arterial hypertension (PAH) in patients with tuberculosis-destroyed lung (TDL), a sequela of pulmonary tuberculosis. We identified the risk factors for PAH and their effects on acute exacerbation and mortality in patients with TDL, as well as the clinical differences in patients with chronic obstructive pulmonary disease (COPD) and PAH.

METHODS

A retrospective cohort study was conducted from 2010 through 2015 in a municipal referral hospital in South Korea. PAH was defined when echocardiographic pulmonary arterial pressure (PAP) was >40 mmHg. The clinical features and course of TDL patients with or without PAH were evaluated and differences between patients with COPD and PAH were analyzed.

RESULTS

Among the 195 patients with TDL, echocardiographic data were available in 53 patients, and their mean PAP was 50.72±23.99 mmHg. The PAH group (n=37) had a smaller lung volume (forced vital capacity % predicted, 51.55% vs 72.37%, P<0.001) and more extensively destroyed lungs (3.27 lobes vs 2 lobes, P<0.001) than those in the non-PAH group (n=16). A higher PAP was significantly correlated with a higher frequency of acute exacerbation (r=0.32, P=0.02). Multivariate analyses did not reveal any significant risk factors contributing to PAH in patients with TDL. Compared to COPD patients with PAH, TDL patients with PAH have smaller lung volume but a less severe airflow limitation. Tricuspid regurgitation and a D-shaped left ventricle during diastole were more frequently observed in TDL patients. The risk of exacerbation was not different between patients with PAH in COPD and TDL.

CONCLUSION

PAH in patients with TDL was associated with severity of lung destruction but risk of exacerbation and mortality did not significantly differ between patients with PAH and without PAH.

Ambient Coarse Particulate Matter and the Right Ventricle: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Coarse particulate matter (P10-2.5) is primarily mechanically generated and includes crustal material, brake and tire wear, and biological particles. PM10-2.5 is associated with pulmonary disease, which can lead to right ventricular (RV) dysfunction. Although RV characteristics have been associated with combustion-related pollutants, relationships with PM10-2.5 remain unknown.

OBJECTIVES

To quantify cross-sectional associations between RV dysfunction and PM10-2.5 mass and components among older adults and susceptible populations.

METHODS

We used baseline cardiac magnetic resonance images from 1,490 participants (45-84 y old) from the Multi-Ethnic Study of Atherosclerosis and assigned 5-y residential concentrations of PM10-2.5 mass, copper, zinc, phosphorus, silicon, and endotoxin, using land-use regression models. We quantified associations with RV mass, end-diastolic volume, and ejection fraction after control for risk factors and copollutants using linear regression. We further examined personal susceptibility.

RESULTS

We found positive associations of RV mass and, to a lesser extent, end diastolic volume with PM10-2.5 mass among susceptible populations including smokers and persons with emphysema. After adjustment for copollutants, an interquartile range increase in PM10-2.5 mass (2.2 μg/m3) was associated with 0.5 g (95% CI: 0.0, 1.0), 0.9 g (95% CI: 0.1, 1.7), and 1.4 g (95% CI: 0.4, 2.5) larger RV mass among former smokers, current smokers, and persons with emphysema, respectively. No associations were found with healthy individuals or with ejection fraction.

CONCLUSIONS

Alterations to RV structure may represent a mechanism by which long-term PM10-2.5 exposure increases risks for adverse respiratory and cardiovascular outcomes, especially among certain susceptible populations. https://doi.org/10.1289/EHP658.

Pulmonary hypertensive vasculopathy in parenchymal lung diseases and/or hypoxia: Number 1 in the Series "Pathology for the clinician" Edited by Peter Dorfmüller and Alberto Cavazza

Pulmonary hypertension (PH) with complicating chronic lung diseases and/or hypoxia falls into group 3 of the updated classification of PH. Patients with chronic obstructive lung disease (COPD), diffuse lung disease (such as idiopathic pulmonary fibrosis (IPF)) and with sleep disordered breathing are particularly exposed to the risk of developing PH. Although PH in such a context is usually mild, a minority of patients exhibit severe haemodynamic impairment, defined by a mean pulmonary arterial pressure (mPAP) of ≥35 mmHg or mPAP values ranging between 25 mmHg and 35 mmHg with a low cardiac index (<2 L·min^-1·m^-2). The overlap between lung parenchymal disease and PH heavily affects life expectancy in such a patient population and complicates their therapeutic management. In this review we illustrate the pathological features and the underlying pathophysiological mechanisms of pulmonary circulation in chronic lung diseases, with an emphasis on COPD, IPF and obstructive sleep apnoea syndrome.

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 hyperinflation due to gas trapping and pulmonary artery size: The MESA COPD Study

Background

Pulmonary hypertension is associated with increased morbidity and mortality in chronic obstructive pulmonary disease (COPD). Since pulmonary artery (PA) size increases in pulmonary hypertension, we measured PA cross-sectional area using magnetic resonance imaging (MRI) to test the hypothesis that pulmonary hyperinflation due to gas trapping is associated with PA cross-sectional area in COPD.

Methods

The MESA COPD Study recruited participants with COPD and controls from two population-based cohort studies ages 50–79 years with 10 or more pack-years and free of clinical cardiovascular disease. Body plethysmography was performed according to standard criteria. Cardiac MRI was performed at functional residual capacity to measure the cross-sectional area of the main PA. Percent emphysema was defined as the percentage of lung voxels less than -950 Hounsfield units as assessed via x-ray computed tomography. Analyses were adjusted for age, gender, height, weight, race-ethnicity, the forced expiratory volume in one second, smoking status, pack-years, lung function, oxygen saturation, blood pressure, left ventricular ejection fraction and percent emphysema.

Results

Among 106 participants, mean residual volume was 1.98±0.71 L and the mean PA cross-sectional area was 7.23±1.72 cm². A one standard deviation increase in residual volume was independently associated with an increase in main PA cross-sectional area of 0.55 cm² (95% CI 0.18 to 0.92; p = 0.003). In contrast, there was no evidence for an association with percent emphysema or total lung capacity.

Conclusion

Increased residual volume was associated with a larger PA in COPD, suggesting that gas trapping may contribute to pulmonary hypertension in COPD.

Recent Progress in Research on the Pathogenesis of Pulmonary Thromboembolism: An Old Story with New Perspectives

Pulmonary thromboembolism (PTE) is part of a larger clinicopathological entity, venous thromboembolism. It is also a complex, multifactorial disorder divided into four major disease processes including venous thrombosis, thrombus in transit, acute pulmonary embolism, and pulmonary circulation reconstruction. Even when treated, some patients develop chronic thromboembolic pulmonary hypertension. PTE is also a common fatal type of pulmonary vascular disease worldwide, but earlier studies primarily focused on the pathological changes in the blood component of the disease. With contemporary advances in molecular and cellular biology, people are becoming increasingly aware of coagulation pathways, the function of vascular smooth muscle cells, microparticles, and the inflammatory pathways that play key roles in PTE. Combined hypoxia and immune research has revealed that PTE should be regarded as a class of complex diseases caused by multiple factors involving the vascular microenvironment and vascular cell dysfunction.

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.

Follistatin-like 1 protects against hypoxia-induced pulmonary hypertension in mice

Pulmonary hypertension (PH) remains a life-limiting disease characterized by pulmonary vascular remodelling due to aberrant proliferation and migration of pulmonary artery smooth muscle cells (PASMCs), thus leading to raised pulmonary arterial pressure and right ventricular hypertrophy. Secreted glycoprotein follistatin-like 1 (FSTL1) has been reported to ameliorate tissue remodelling in cardiovascular injuries. However, the role of FSTL1 in deranged pulmonary arteries remains elusive. We found that there were higher serum levels of FSTL1 in patients with PH related to chronic obstructive pulmonary diseases (COPD) and in mice model of hypoxia-induced PH (HPH). Haploinsufficiency of Fstl1 in mice contributed to an exacerbated HPH, as demonstrated by increased right ventricular systolic pressure, pulmonary arterial muscularization and right ventricular hypertrophy index. Conversely, FSTL1 administration attenuated HPH. In cultured human PASMCs, hypoxia-promoted cellular viability, DNA synthesis and migration were suppressed by exogenous FSTL1 but enhanced by small interfering RNA targeting FSTL1. Additionally, FSTL1 inhibited the proliferation and migration of PASMCs via extracellular regulated kinase (ERK) signal pathway. All these findings indicate that FSTL1 imposed a protective modulation on pulmonary vascular remodelling, thereby suggesting its role in the regulation of HPH.

Novel putative pharmacological therapies to protect the right ventricle in pulmonary hypertension: a review of current literature

Pulmonary hypertension (PH) is defined by elevated mean pulmonary artery pressure following the pathological remodelling of small pulmonary arteries. An increase in right ventricular (RV) afterload results in RV hypertrophy and RV failure. The pathophysiology of PH, and RV remodelling in particular, is not well understood, thus explaining, at least in part, why current PH therapies have a limited effect. Existing therapies mostly target the pulmonary circulation. Because the remodelled RV fails to support normal cardiac function, patients eventually succumb from RV failure. Developing novel therapies that directly target the function of the RV may therefore benefit patients with PH. In the past decade, several promising studies have investigated novel cardioprotective strategies in experimental models of PH. This review aims to comprehensively discuss and highlight these novel experimental approaches to confer, in the long-term, greater health benefit in patients with PH.

Alveolar Hypoxia-Induced Pulmonary Inflammation: From Local Initiation to Secondary Promotion by Activated Systemic Inflammation

Pulmonary hypertension (PH) is a pathological condition with high mortality and morbidity. Hypoxic PH (HPH) is a common form of PH occurring mainly due to lung disease and/or hypoxia. Most causes of HPH are associated with persistent or intermittent alveolar hypoxia, including exposure to high altitude and chronic obstructive respiratory disease. Recent evidence suggests that inflammation is a critical step for HPH initiation and development. A detailed understanding of the initiation and progression of pulmonary inflammation would help in exploring potential clinical treatments for HPH. In this review, the mechanism for alveolar hypoxia-induced local lung inflammation and its progression are discussed as follows: (1) low alveolar PO2 levels activate resident lung cells, mainly the alveolar macrophages, which initiate pulmonary inflammation; (2) systemic inflammation is induced by alveolar hypoxia through alveolar macrophage activation; (3) monocytes are recruited into the pulmonary circulation by alveolar hypoxia-induced macrophage activation, which then contributes to the progression of pulmonary inflammation during the chronic phase of alveolar hypoxia, and (4) alveolar hypoxia-induced systemic inflammation contributes to the development of HPH. We hypothesize that a combination of alveolar hypoxia-induced local lung inflammation and the initiation of systemic inflammation ("second hit") is essential for HPH progression.

Accuracy of CT Pulmonary Artery Diameter for Pulmonary Hypertension in End-Stage COPD

Introduction

Pulmonary hypertension (PH) in COPD is associated with a higher mortality and an increased risk on exacerbations compared to COPD patients without PH. The aim was to evaluate the diagnostic value of pulmonary artery (PA) measurements on chest computed tomography (CT) for PH in end-stage COPD.

Methods

COPD patients evaluated for eligibility for lung transplantation between 2004 and 2015 were retrospectively analyzed. Clinical characteristics, chest CTs, spirometry, and right-sided heart catheterizations (RHC) were studied. Diameters of PA and ascending aorta (A) were measured on CT. Diagnostic properties of different cut-offs of PA diameter and PA:A ratio in diagnosing PH were calculated.

Results

Of 92 included COPD patients, 30 (32.6 %) had PH at RHC (meanPAP > 25 mm Hg). PA:A > 1 had a negative predictive value (NPV) of 77.9 % and a positive predictive value (PPV) of 63.1 % with an odds ratio (OR (CI 95 %)) of 5.60 (2.00–15.63). PA diameter ≥30 mm had a NPV of 78 % and PPV of 64 % with an OR (CI 95 %) of 6.95 (2.51–19.24).

Conclusion

A small PA diameter and PA:A make the presence of PH unlikely but cannot exclude its presence in end-stage COPD. A large PA diameter and PA:A maybe used to detect PH early.

Upregulation of MicroRNA-214 Contributes to the Development of Vascular Remodeling in Hypoxia-induced Pulmonary Hypertension Via Targeting CCNL2

Hypoxia-induced pulmonary hypertension (PH), which is characterized by vascular remodeling of blood vessels, is a significant complication of chronic obstructive pulmonary disease (COPD). In this study, we screened 13 candidate miRNAs in pulmonary artery smooth muscle cells (PASMCs) harvested from COPD patients with PH (n = 18) and normal controls (n = 15) and found that the expression of miR-214 was differentially expressed between these two groups. Additionally, cyclin L2 (CCNL2) was validated as a target of miR-214 in PASMCs using a luciferase assay. Based on real-time PCR, immunohistochemistry and western blot, the expression of CCNL2 was substantially downregulated in PASMCs from COPD patients with PH compared with those from normal controls. Moreover, the relationship between miRNA and mRNA expression was confirmed using real-time PCR and western blot in PASMCs transfected with miR-214 mimics. Furthermore, the introduction of miR-214 significantly promoted the proliferation of PASMCs by suppressing cell apoptosis, and this effect was mediated by the downregulation of CCNL2. Exposure of PASMCs to hypoxia significantly increased the expression of miR-214, decreased the expression of CCNL2, and promoted cell proliferation. However, these effects were significantly attenuated by the introduction of miR-214 inhibitors, which significantly downregulated miR-214 expression and upregulated CCNL2 expression.

Study of Pulmonary Hypertension in Patients Suffering from Chronic Obstructive Pulmonary Disease

Pulmonary hypertension (PAH) represents a frequent complication in patients suffering from chronic obstructive pulmonary disease (COPD), but the impact of accelerated inflammatory status on the pulmonary vascular bed is still insufficiently studied.

OBJECTIVES

The study of the PAH's prevalence in patients suffering from COPD, its severity compared with lung function and the correlation with certain clinical, biological and functional parameters.

MATERIAL AND METHOD

The study was performed on a group of 64 patients, average age 53 years, 42 of whom were men (65,62%), suffering from COPD who were admitted to the Emergency County Hospital Craiova, on the II-nd Medical Clinic, within a period of 18 months. When assessing the patients their clinical state was stable, without acute exacerbations items. The control group included 61 patients suffering from other diseases without inflammatory background, who were hospitalized in clinic in the same period. All the patients included in the study were evaluated by: physical examination, thoracic radiological examination, spirometry, inflammatory syndrome, echocardiography Doppler and oximetry.

RESULTS

The results of the study show a prevalence of 54.6 % PAH and a statistically significant impact of age, duration of the disease, Sa O2, inflammatory status, which was quantified in the study by ESR, serum levels of CRP and serum level of TNF alpha over the risk of developing COPD in patients suffering from PAH.

CONCLUSIONS

The occurrence and the severity of PAH in patients suffering from COPD seems to be correlated with their age, duration of the disease, Sa O2 and serum levels of inflammatory markers.

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.

Lung function in pulmonary hypertension

Breathlessness is a common symptom in pulmonary hypertension (PH) and an important cause of morbidity. Though this has been attributed to the well described pulmonary vascular abnormalities and subsequent cardiac remodelling, changes in the airways of these patients have also been reported and may contribute to symptoms. Our understanding of these airway abnormalities is poor with conflicting findings in many studies. The present review evaluates these studies for the major PH groups. In addition we describe the role of cardiopulmonary exercise testing in the assessment of pulmonary arterial hypertension (PAH) by evaluating cardiopulmonary interaction during exercise. As yet, the reasons for the abnormalities in lung function are unclear, but potential causes and the possible role of inflammation are discussed. Future research is required to provide a better understanding of this to help improve the management of these patients.

Prevalence of Pulmonary Hypertension and its Influence on Survival in Patients With Advanced Chronic Obstructive Pulmonary Disease Prior to Lung Transplantation

INTRODUCTION

Prevalence of pulmonary hypertension (PH) and its influence on survival in chronic obstructive pulmonary disease (COPD) are not well studied in the lung allocation score (LAS) era.

METHODS

The UNOS database was queried from 2005 to 2013 to identify first-time adult lung transplant candidates with COPD who were tracked from wait list entry date until death or censoring to determine both prevalence and influence of PH. Using right heart catheterization measurements, mild PH was defined as mean pulmonary artery pressure (mPAP) ≥ 25 mmHg and severe ≥ 35 mmHg.

RESULTS

Of 1315 COPD candidates not transplanted, 1243 were used for survival analysis using Cox proportional hazards models, and 1010 (mild PH) and 244 (severe PH) were used for propensity score matching, respectively. A total of 52% (652) of subjects had PH mPAP ≥ 25 mmHg. Univariate analysis revealed significant differences in survival for mild PH (HR = 1.769; 95% CI: 1.331, 2.351; p < 0.001) and severe PH (HR = 3.271; 95% CI: 2.311, 4.630; p < 0.001). Kaplan-Meier survival function demonstrated significant disparities for mild PH (Log-rank test: Chi-square1: 15.87, p < 0.0001) and severe PH (Log-rank test: Chi-square1: 50.13, p < 0.0001). Multivariate Cox models identified significant risk for death for mild PH (HR = 1.987; 95% CI: 1.484, 2.662; p < 0.001) and severe PH (HR = 3.432; 95% CI: 2.410, 4.888; p < 0.001). Propensity score matching confirmed increased mortality hazard associated with mild PH (HR = 2.280; 95% CI: 1.425, 3.649; p = 0.001) and severe PH (HR = 7.000; 95% CI: 2.455, 19.957; p < 0.001).

CONCLUSIONS

PH is highly prevalent in advanced COPD and associated with a significantly higher risk for mortality.

The Three A's in Asthma - Airway Smooth Muscle, Airway Remodeling & Angiogenesis

Asthma affects more than 300 million people worldwide and its prevalence is still rising. Acute asthma attacks are characterized by severe symptoms such as breathlessness, wheezing, tightness of the chest, and coughing, which may lead to hospitalization or death. Besides the acute symptoms, asthma is characterized by persistent airway inflammation and airway wall remodeling. The term airway wall remodeling summarizes the structural changes in the airway wall: epithelial cell shedding, goblet cell hyperplasia, hyperplasia and hypertrophy of the airway smooth muscle (ASM) bundles, basement membrane thickening and increased vascular density. Airway wall remodeling starts early in the pathogenesis of asthma and today it is suggested that remodeling is a prerequisite for other asthma pathologies. The beneficial effect of bronchial thermoplasty in reducing asthma symptoms, together with the increased potential of ASM cells of asthmatics to produce inflammatory and angiogenic factors, indicate that the ASM cell is a major effector cell in the pathology of asthma. In the present review we discuss the ASM cell and its role in airway wall remodeling and angiogenesis.

Influence of pulmonary hypertension on survival in advanced lung disease

BACKGROUND

Effects of pulmonary hypertension (PH) in advanced lung disease remain unclear.

METHODS

The United Network for Organ Sharing database was queried from 1987 to 2013 to assess survival lung transplant candidates to determine influence of PH in advanced lung disease. Thresholds included mean pulmonary artery pressure ≥ 25 mmHg (mild PH) and 35 mmHg (severe PH).

RESULTS

Of 12,405 listed possible candidates, 10,158 were used for univariate analysis, 7050 for Kaplan-Meier (KM) function, 6196 for multivariate Cox models, and 5328 (mild PH) and 1910 (severe PH) for propensity score matching (PSM). For mild and severe PH, univariate revealed that PH was associated with survival difference (HR = 1.530, 95% CI 1.416, 1.654, p < 0.001) and (HR = 2.033, 95% CI 1.851, 2.232, p < 0.001), respectively. KM function curves demonstrated a significant difference for mild PH (Log-rank test: Chi square (df = 1): 117.76, p < 0.0001) and severe PH (Log-rank test: Chi square (df = 1): 230.91, p < 0.0001). Multivariate Cox models also found a significant increased risk for death for mild PH (HR = 1.750, 95% CI 1.606, 1.907, p < 0.001) and severe PH (HR = 2.088, 95% CI 1.879, 2.319, p < 0.001). PSM confirmed this increased risk for death for mild PH (HR = 1.695, 95% CI 1.502, 1.914, p < 0.001) and severe PH (HR = 1.976, 95% CI 1.641, 2.379, p < 0.001).

CONCLUSIONS

PH is associated with significant increased risk for death in patients with advanced lung disease.

[COPD and heart disease]

Cardiovascular diseases are highly prevalent in patients with chronic obstructive pulmonary disease (COPD). Approximately one out of three patients with COPD dies of cardiovascular disease. Overlap syndrome (COPD and obstructive sleep apnea), pulmonary hypertension and lung hyperinflation have a further impact on cardiovascular function in patients with COPD.

Intermittent positive pressure ventilation increases diastolic pulmonary arterial pressure in advanced COPD

OBJECTIVES

To measure the impact of intermittent positive pressure ventilation (IPPV) on diastolic pulmonary arterial pressure (dPAP) and pulmonary pulse pressure in patients with advanced COPD.

BACKGROUND

The physiological effects of raised intrathoracic pressures upon the pulmonary circulation have not been fully established.

METHODS

22 subjects with severe COPD receiving IPPV were prospectively assessed with pulmonary and radial arterial catheterization. Changes in dPAP were assessed from end-expiration to early inspiration during low and high tidal volume ventilation.

RESULTS

Inspiration during low tidal volume IPPV increased the median [IQR] dPAP by 3.9 [2.5-4.8] mm Hg (P < 0.001). During high tidal volume, similar changes were observed. The IPPV-associated change in dPAP was correlated with baseline measures of PaO2 (rho = 0.65, P = 0.005), pH (rho = 0.64, P = 0.006) and right atrial pressure (rho = -0.53, P = 0.011).

CONCLUSIONS

In severe COPD, IPPV increases dPAP and reduces pulmonary pulse pressure during inspiration.

Epidemiology and clinical impact of major comorbidities in patients with COPD

Comorbidities are frequent in chronic obstructive pulmonary disease (COPD) and significantly impact on patients’ quality of life, exacerbation frequency, and survival. There is increasing evidence that certain diseases occur in greater frequency amongst patients with COPD than in the general population, and that these comorbidities significantly impact on patient outcomes. Although the mechanisms are yet to be defined, many comorbidities likely result from the chronic inflammatory state that is present in COPD. Common problems in the clinical management of COPD include recognizing new comorbidities, determining the impact of comorbidities on patient symptoms, the concurrent treatment of COPD and comorbidities, and accurate prognostication. The majority of comorbidities in COPD should be treated according to usual practice, and specific COPD management is infrequently altered by the presence of comorbidities. Unfortunately, comorbidities are often under-recognized and under-treated. This review focuses on the epidemiology of ten major comorbidities in patients with COPD. Further, we emphasize the clinical impact upon prognosis and management considerations. This review will highlight the importance of comorbidity identification and management in the practice of caring for patients with COPD.

[Pulmonary hypertension in chronic respiratory diseases]

Pulmonary hypertension is frequent in advanced chronic respiratory diseases, with an estimated prevalence at the time of pulmonary transplantation of 30-50 % in idiopathic pulmonary fibrosis, 30-50 % in chronic obstructive pulmonary disease, 50 % in combined pulmonary fibrosis and emphysema, 75 % in sarcoidosis, and more than 75 % of cases in pulmonary Langerhans cell histiocytosis. Histologic features include varying degrees of pulmonary arterial remodeling (prominent), vascular rarefaction (emphysema), fibrosis or specific involvement of the pulmonary arteries (idiopathic pulmonary fibrosis, sarcoidosis, lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis), in situ thrombosis, and frequently associated involvement of the pulmonary veins (idiopathic pulmonary fibrosis, sarcoidosis). Pulmonary hypertension is usually detected using echocardiography with Doppler, however right heart catheterisation is required to confirm precapillary pulmonary hypertension defined by pulmonary artery pressure ≥ 25 mm Hg, with pulmonary artery wedge pressure ≤ 15 mm Hg. When present, it is associated with decreased exercise capacity and worse mortality. Pulmonary hypertension in chronic respiratory disease is almost invariably multifactorial; hypoxia is one of its main determinants, however supplemental oxygen therapy rarely reverses pulmonary hypertension. Management of pulmonary hypertension in chronic respiratory disease is mostly based on the optimal treatment of the underlying disease. Available data do not support the use of drug therapies specific for pulmonary hypertension in the setting of chronic respiratory diseases, however very few clinical studies have been conducted so far specifically in this context.