Pulmonary hypertension in advanced chronic obstructive pulmonary disease:

Predictive Value of GDF-15 and sST2 for Pulmonary Hypertension in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

To confirm whether growth differentiation factor-15 (GDF-15) and soluble suppression of tumorigenicity 2 (sST2) are indicators of pulmonary hypertension in acute exacerbation of chronic obstructive pulmonary disease (AECOPD-PH).

Methods

All patients admitted to the hospital with AECOPD between July 2020 and October 2021 were enrolled. The patients were then categorized into AECOPD and AECOPD-PH groups according to PH probability, and the differences in GDF-15 and sST2 serum levels in the AECOPD and AECOPD-PH groups were compared. Correlation analysis was carried out to explore the association between GDF-15 and sST2 serum levels and the length of hospital stay of patients with AECOPD-PH. Receiver operating characteristic curve analysis was used to assess the clinical significance of GDF-15 and sST2 in predicting patients with AECOPD-PH.

Results

Included in this study were 126 patients with AECOPD, including 69 with AECOPD and 57 with AECOPD-PH. The serum levels of GDF-15 and sST2 in the AECOPD-PH group were significantly higher than those in the AECOPD group (P < 0.05). There was no significant correlation between the length of hospital stay in AECOPD-PH patients and GDF-15 and sST2 serum levels (P > 0.05). The area under the curves of GDF-15, sST2, and GDF-15 + sST2 for predicting AECOPD-PH and AECOPD-PH patients with poor prognosis were >0.60 and 0.70, respectively. The optimal cutoff values of GDF-15 and sST2 for predicting AECOPD-PH were 1125.33 pg/mL and 80.68 ng/mL and 1309.72 pg/mL and 59.10 ng/mL for predicting AECOPD-PH patients with poor prognosis, respectively.

Conclusion

GDF-15 and sST2 levels may be useful in the prediction of AECOPD-PH.

Pachymic Acid Ameliorates Pulmonary Hypertension by Regulating Nrf2-Keap1-ARE Pathway

OBJECTIVE

Pulmonary hypertension (PH) is a severe pulmonary vascular disease that eventually leads to right ventricular failure and death. The purpose of this study was to investigate the mechanism by which pachymic acid (PA) pretreatment affects PH and pulmonary vascular remodeling in rats.

METHODS

PH was induced via hypoxia exposure and administration of PA (5 mg/kg per day) in male Sprague-Dawley rats. Hemodynamic parameters were measured using a right ventricular floating catheter and pulmonary vascular morphometry was measured by hematoxylin-eosin (HE), α-SMA and Masson staining. MTT assays and EdU staining were used to detect cell proliferation, and apoptosis was analyzed by TUNEL staining. Western blotting and immunohistochemistry were used to detect the expression of proteins related to the Nrf2-Keap1-ARE pathway.

RESULTS

PA significantly alleviated hypoxic PH and reversed right ventricular hypertrophy and pulmonary vascular remodeling. In addition, PA effectively inhibited proliferation and promoted apoptosis in hypoxia-induced pulmonary artery smooth muscle cells (PASMCs). Moreover, PA pretreatment inhibited the expression of peroxy-related factor (MDA) and promoted the expression of antioxidant-related factors (GSH-PX and SOD). Furthermore, hypoxia inhibited the Nrf2-Keap1-ARE signaling pathway, while PA effectively activated this pathway. Most importantly, addition of the Nrf2 inhibitor ML385 reversed the inhibitory effects of PA on ROS generation, proliferation, and apoptosis tolerance in hypoxia-induced PASMCs.

CONCLUSION

Our study suggests that PA may reverse PH by regulating the Nrf2-Keap1-ARE signaling pathway.

Influence of atrial fibrillation on cardiac prognosis in chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD), a known risk factor for the development of congestive heart failure (CHF), was recently shown to predict the prevalence of atrial fibrillation (AF). Here, we explore the influence of AF on cardiac prognosis in COPD patients.

Methods

A total of 339 consecutive patients who underwent spirometry from 2010 to 2013 for various reasons were retrospectively examined. Based on the diagnostic criteria, patients were stratified into COPD and non-COPD groups, which were both further divided into those with AF (chronic AF or paroxysmal AF) or sinus rhythm (SR) based on previous electrocardiography results. Significances of differences in cardiac events were assessed by the chi-square test. Multivariate logistic regression analyses and Cox proportional hazard models were applied to evaluate the influence of AF on cardiac events.

Results

Of the 339 patients, 190 were diagnosed with COPD, with 42 of these were having AF. During the mean follow-up period of 7.4 ± 0.8 years, CHF developed more frequently in COPD patients with AF than in COPD patients without AF [50% vs 7%; odds ratio (OR) 12.4, 95% confidence interval (CI): 5.25–29.49, p < 0.05]. AF was an independent predictor of CHF development (OR 20.4, 95% CI: 6.55–79.80, p < 0.05) and cardiac mortality (OR 2.8, 95% CI: 1.79–4.72, p < 0.05). Moreover, positive correlations were found between the severity of pulmonary obstruction with AF and CHF development (R = 0.69, p < 0.05), as well as cardiac mortality (R = 0.78.p < 0.05).

Conclusions

These results suggest that AF may be strongly associated with cardiac mortality and CHF in COPD patients.

LPS enhances TLR4 expression and IFN‑γ production via the TLR4/IRAK/NF‑κB signaling pathway in rat pulmonary arterial smooth muscle cells

The aim of the present study was to investigate the role of the Toll-like receptor (TLR)4 signaling pathway in cellular response to lipopolysaccharide (LPS) in rat pulmonary artery smooth muscle cells (PASMCs). Chronic obstructive pulmonary disease (COPD) rats were established with passive inhaling cigarette smoke plus injection of LPS. The TLR4 protein in lung tissues was determined with immunohistochemical staining and protein levels of the components of the TLR4 pathway in PASMCs were analyzed with western blotting. The production of interferon (IFN)-γ upon LPS stimulation in PASMCs was measured with ELISA. TLR4 expression in lung tissue from COPD rats was increased obviously compared with that in normal group. LPS enhances TLR4 expression in rat PASMCs and induced production of IFN-γ dramatically. LPS treatment resulted in increased phosphor-interleukin-1 receptor-associated kinase (IRAK), IκB and IκB kinase, as well as the total protein of nuclear factor (NF)-κB p65. TLR4 inhibitor TAK-242, IRAK1/4 inhibitor and NF-κB inhibitor Bay 117082 were capable of suppressing the effects of LPS. TLR4 signaling pathway is functional in PASMCs, and may be involved in the inflammatory response during the pathogenesis of COPD.

Upregulation of SRF Is Associated With Hypoxic Pulmonary Hypertension by Promoting Viability of Smooth Muscle Cells via Increasing Expression of Bcl-2

The aim of study was to investigate the involvement of hypoxia-induced upregulation of serum response factor (SRF) and its downstream effector, B cell leukemia-2 (Bcl-2), in hypoxia-induced pulmonary hypertension (PH). Immunohistochemistry analysis and western blot analysis were used to detect the levels of SRF and Bcl-2 in rats exposed to hypoxia. Furthermore, the regulatory relationship between SRF and Bcl-2 was investigated in PASMCs using real-time PCR and western-blot analysis. We found that mPAP (mean pulmonary arterial pressure) and WA (the ratio of vascular wall area to external diameter) were increased after exposure to hypoxia, while LA (the ratio of vascular lumen area to total area) decreased after exposure to hypoxia. The immunohistochemistry analysis displayed a substantial increase in SRF and Bcl-2 in pulmonary arterial walls after 14 days of hypoxia. And the western blotting showed that SRF and Bcl-2 protein levels were much higher after 7 days of hypoxia and then remained at a high level. And then the levels of SRF and Bcl-2 in pulmonary artery smooth muscle cells (PASMCs) exposed to hypoxia were substantially suppressed following introduction of SRF siRNA, and the level of Bcl-2 was remarkably inhibited by Bcl-2 siRNA, while Bcl-2 siRNA had no effect on SRF level. Finally, SRF siRNA, and Bcl-2 siRNA significantly reduced viability of PASMCs exposed to hypoxia, and enhanced apoptosis of PASMCs exposed to hypoxia. These data validated that SRF responded to hypoxia, which subsequently was involved in pulmonary hypertension by abnormally promoting viability of PASMCs via modulating expression of Bcl-2. J. Cell. Biochem. 118: 2731-2738, 2017. © 2017 Wiley Periodicals, Inc.

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.

Venous thromboembolism and persistent pulmonary hypertension in cancer patients: a cross-sectional study

BACKGROUND

Cancer patients are at increased risk for venous thromboembolism (VTE).

OBJECTIVE

This monocenter cross-sectional study prospectively assessed the association between a history of ≥1 VTE episode and the presence of pulmonary hypertension (PH) among cancer patients presenting with pulmonary or cardiac symptoms.

METHODS

A consecutive series of 583 patients underwent a diagnostic work-up for heart and lung disease. PH was diagnosed if a patient's peak systolic pressure gradient across the tricuspid valve was ≥35 mmHg, as measured by echocardiography. Using multiple logistic regression analysis, the association between VTE and PH was assessed, following adjustments for age, the presence of severe airway obstruction, atrial fibrillation and left heart diseases.

RESULTS

The prevalence values for PH (n = 90) and a history of VTE (n = 72) were 15.4 and 12.3 %, respectively. The median time interval between the first VTE episode and referral was 43 months. The odds of PH was higher in the subgroup with VTE (19/72; 26.4 %) than that without VTE (71/511; 13.9 %) in the unadjusted analysis [odds ratio (OR) 2.2, 95 % confidence interval (CI) 1.2, 4.0] and the adjusted model [OR 2.4, 95 % CI 1.2, 4.5]. The risk of PH did not depend on the time interval between VTE and referral. Older age and the presence of severe airway obstruction, atrial fibrillation, and left heart diseases were also associated with an increased odds of PH.

CONCLUSION

In cancer patients presenting with cardiac or pulmonary symptoms, previous VTE is associated with an increased risk of persistent PH.

Mammalian target of rapamycin overexpression antagonizes chronic hypoxia-triggered pulmonary arterial hypertension via the autophagic pathway

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disorder with high morbidity and mortality, and is characterized by excessive growth of endothelial cells. Recently, the mammalian target of rapamycin (mTOR) has attracted increasing attention due to its potential as a therapeutic target against certain diseases associated with proliferative and metabolic abnormalities. However, the effect on mTOR on PAH has not yet been elucidated. In the present study, a marked downregulation of mTOR was observed in PAH patients. Following construction of a mouse model of PAH by chronic exposure to hypoxia, adenovirus-mediated upregulation of mTOR significantly attenuated right ventricular systolic pressure, right ventricular hypertrophy and wall thickness of pulmonary arterioles, indicating a protective effect of mTOR on PAH. Further analysis confirmed that mTOR overexpression inhibited autophagy triggered by hypoxia through blocking light chain 3 II expression and increasing p62 levels. In vitro, hypoxia enhanced the proliferation of human pulmonary artery endothelial cells (PAECs), which was markedly abrogated by mTOR overexpression. Of note, upregulation of mTOR inhibited the hypoxia-induced autophagy pathway, which contributed to cell proliferation, while silencing of autophagy by RNA interference with ATG5 significantly inhibited cell proliferation. In conclusion, the results of the present study suggested a potential protective effect of mTOR on the progression of PAH by suppressing PAEC proliferation through blocking the autophagic pathway. Therefore, the present study suggested that mTOR is a promising therapeutic agent against PAH.

Assessment of the relationship between morphological emphysema phenotype and corresponding pulmonary perfusion pattern on a segmental level

PURPOSE

Distinct morphological emphysema phenotypes were assessed by CT to show characteristic perfusion defect patterns.

MATERIAL/METHODS

Forty-one patients with severe emphysema (GOLD III/IV) underwent three-dimensional high resolution computed tomography (3D-HRCT) and contrast-enhanced magnetic resonance (MR) perfusion. 3D-HRCT data was visually analyzed for emphysema phenotyping and quantification by consensus of three experts in chest-radiology. The predominant phenotype per segment was categorized as normal, centrilobular, panlobular or paraseptal. Segmental lung perfusion was visually analyzed using six patterns of pulmonary perfusion (1-normal; 2-mild homogeneous reduction in perfusion; 3-heterogeneous perfusion without focal defects; 4-heterogeneous perfusion with focal defects; 5-heterogeneous absence of perfusion; 6-homogeneous absence of perfusion), with the extent of the defect given as a percentage.

RESULTS

730 segments were evaluated. CT categorized 566 (78%) as centrilobular, 159 (22%) as panlobular and 5 (<1%) as paraseptal with no normals. Scores with regards to MR perfusion patterns were: 1-0; 2-0; 3-28 (4%); 4-425 (58%); 5-169 (23%); 6-108 (15%). The predominant perfusion pattern matched as follows: 70 % centrilobular emphysema - heterogeneous perfusion with focal defects (score 4); 42% panlobular--homogeneous absence of perfusion (score 5); and 43% panlobular--heterogeneous absence of perfusion (score 6).

CONCLUSION

MR pulmonary perfusion patterns correlate with the CT phenotype at a segmental level in patients with severe emphysema.

KEY POINTS

• MR perfusion patterns correlate with the CT phenotype in emphysema. • Reduction of MR perfusion is associated with loss of lung parenchyma on CT • Centrilobular emphysema shows heterogeneous perfusion reduction while panlobular emphysema shows loss of perfusion.

Pulmonary hypertension and right heart dysfunction in chronic lung disease

Group 3 pulmonary hypertension (PH) is a common complication of chronic lung disease (CLD), including chronic obstructive pulmonary disease (COPD), interstitial lung disease, and sleep-disordered breathing. Development of PH is associated with poor prognosis and may progress to right heart failure, however, in the majority of the patients with CLD, PH is mild to moderate and only a small number of patients develop severe PH. The pathophysiology of PH in CLD is multifactorial and includes hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, small vessel destruction, and fibrosis. The effects of PH on the right ventricle (RV) range between early RV remodeling, hypertrophy, dilatation, and eventual failure with associated increased mortality. The golden standard for diagnosis of PH is right heart catheterization, however, evidence of PH can be appreciated on clinical examination, serology, radiological imaging, and Doppler echocardiography. Treatment of PH in CLD focuses on management of the underlying lung disorder and hypoxia. There is, however, limited evidence to suggest that PH-specific vasodilators such as phosphodiesterase-type 5 inhibitors, endothelin receptor antagonists, and prostanoids may have a role in the treatment of patients with CLD and moderate-to-severe PH.

Chronic hypoxia promotes pulmonary artery endothelial cell proliferation through H2O2-induced 5-lipoxygenase

Pulmonary Hypertension (PH) is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia-induced PH development is arachidonate 5-Lipoxygenase (ALOX5). While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia-induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. To test this, human pulmonary artery endothelial cells (HPAEC) were cultured under normoxic (21% O2) or hypoxic (1% O2) conditions for 24-, 48-, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, or the 5-lipoxygenase activating protein inhibitor, MK-886, was administered during hypoxia exposure. ALOX5 expression was measured by qRT-PCR and western blot and HPAEC proliferation was assessed. Our results demonstrate that 24 and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression, hydrogen peroxide (H2O2) release, and HPAEC proliferation. We also demonstrate that targeted ALOX5 gene silencing or inhibition of the ALOX5 pathway by pharmacological blockade attenuates hypoxia-induced HPAEC proliferation. Furthermore, our findings indicate that hypoxia-induced increases in cell proliferation and ALOX5 expression are dependent on H2O2 production, as administration of the antioxidant PEG-catalase blocks these effects and addition of H2O2 to HPAEC promotes proliferation. Overall, these studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway via the generation of H2O2.

Adenosine A2B receptor and hyaluronan modulate pulmonary hypertension associated with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide. The development of pulmonary hypertension (PH) in patients with COPD is strongly associated with increased mortality. Chronic inflammation and changes to the lung extracellular matrix (ECM) have been implicated in the pathogenesis of COPD, yet the mechanisms that lead to PH secondary to COPD remain unknown. Our experiments using human lung tissue show increased expression levels of the adenosine A2B receptor (ADORA2B) and a heightened deposition of hyaluronan (HA; a component of the ECM) in remodeled vessels of patients with PH associated with COPD. We also demonstrate that the expression of HA synthase 2 correlates with mean pulmonary arterial pressures in patients with COPD, with and without a secondary diagnosis of PH. Using an animal model of airspace enlargement and PH, we show that the blockade of ADORA2B is able to attenuate the development of a PH phenotype that correlates with reduced levels of HA deposition in the vessels and the down-regulation of genes involved in the synthesis of HA.

Chronic obstructive pulmonary disease: clinical integrative physiology

Peripheral airway dysfunction, inhomogeneous ventilation distribution, gas trapping, and impaired pulmonary gas exchange are variably present in all stages of chronic obstructive pulmonary disease (COPD). This article provides a cogent physiologic explanation for the relentless progression of activity-related dyspnea and exercise intolerance that all too commonly characterizes COPD. The spectrum of physiologic derangements that exist in smokers with mild airway obstruction and a history compatible with COPD is examined. Also explored are the perceptual and physiologic consequences of progressive erosion of the resting inspiratory capacity. Finally, emerging information on the role of cardiocirculatory impairment in contributing to exercise intolerance in patients with varying degrees of airway obstruction is reviewed.

Biopterin metabolism and eNOS expression during hypoxic pulmonary hypertension in mice

Tetrahydrobiopterin (BH4), which fosters the formation of and stabilizes endothelial NO synthase (eNOS) as an active dimer, tightly regulates eNOS coupling / uncoupling. Moreover, studies conducted in genetically-modified models demonstrate that BH4 pulmonary deficiency is a key determinant in the pathogenesis of pulmonary hypertension. The present study thus investigates biopterin metabolism and eNOS expression, as well as the effect of sepiapterin (a precursor of BH4) and eNOS gene deletion, in a mice model of hypoxic pulmonary hypertension. In lungs, chronic hypoxia increased BH4 levels and eNOS expression, without modifying dihydrobiopterin (BH2, the oxidation product of BH4) levels, GTP cyclohydrolase-1 or dihydrofolate reductase expression (two key enzymes regulating BH4 availability). In intrapulmonary arteries, chronic hypoxia also increased expression of eNOS, but did not induce destabilisation of eNOS dimers into monomers. In hypoxic mice, sepiapterin prevented increase in right ventricular systolic pressure and right ventricular hypertrophy, whereas it modified neither remodelling nor alteration in vasomotor responses (hyper-responsiveness to phenylephrine, decrease in endothelium-dependent relaxation to acetylcholine) in intrapulmonary arteries. Finally, deletion of eNOS gene partially prevented hypoxia-induced increase in right ventricular systolic pressure, right ventricular hypertrophy and remodelling of intrapulmonary arteries. Collectively, these data demonstrate the absence of BH4/BH2 changes and eNOS dimer destabilisation, which may induce eNOS uncoupling during hypoxia-induced pulmonary hypertension. Thus, even though eNOS gene deletion and sepiapterin treatment exert protective effects on hypoxia-induced pulmonary vascular remodelling, increase on right ventricular pressure and / or right ventricular hypertrophy, these effects appear unrelated to biopterin-dependent eNOS uncoupling within pulmonary vasculature of hypoxic wild-type mice.

Role of IL-18 in second-hand smoke-induced emphysema

Chronic second-hand smoke (SHS) exposure comprises the main risk factor for nonsmokers to develop chronic obstructive pulmonary disease (COPD). However, the mechanisms behind the chronic inflammation and lung destruction remain incompletely understood. In this study, we show that chronic exposure of Sprague-Dawley rats to SHS results in a significant increase of proinflammatory cytokine IL-18 and chemokine (C-C motif) ligand 5 in the bronchoalveolar lavage fluid (BALF) and a significant decrease of vascular endothelial growth factor (VEGF) in the lung tissue. SHS exposure resulted in progressive alveolar airspace enlargement, cell death, pulmonary vessel loss, vessel muscularization, collagen deposition, and right ventricular hypertrophy. Alveolar macrophages displayed a foamy phenotype and a decreased expression of the natural inhibitor of IL-18, namely, IL-18 binding protein (IL-18BP). Moreover, IL-18 down-regulated the expression of VEGF receptor-1 and VEGFR receptor-2, and induced apoptosis in pulmonary microvascular endothelial cells in vitro. We also observed a trend toward increased concentrations of IL-18 in the BALF of patients with COPD. Our findings suggest that IL-18-mediated endothelial cell death may contribute to vascular destruction and disappearance in SHS-induced COPD. Moreover, IL-18 and IL-18BP are potential new targets for therapeutics.

Renin-angiotensin system blockade: a novel therapeutic approach in chronic obstructive pulmonary disease

ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin II receptor blockers) are already widely used for the treatment and prevention of cardiovascular disease and their potential role in other disease states has become increasingly recognized. COPD (chronic obstructive pulmonary disease) is characterized by pathological inflammatory processes involving the lung parenchyma, airways and vascular bed. The aim of the present review is to outline the role of the RAS (renin-angiotensin system) in the pathogenesis of COPD, including reference to results from fibrotic lung conditions and pulmonary hypertension. The review will, in particular, address the emerging evidence that ACE inhibition could have a beneficial effect on skeletal muscle function and cardiovascular co-morbidity in COPD patients. The evidence to support the effect of RAS blockade as a novel therapeutic approach in COPD will be discussed.