Pulmonary hypertension in chronic obstructive pulmonary disease

Pulmonary vascular disease in chronic lung diseases: cause or comorbidity?

PURPOSE OF REVIEW

To provide timely and relevant insights into the complex relationship between pulmonary vascular disease (PVD) and chronic lung disease (CLD), focusing on the causative and consequential dynamics between these conditions.

RECENT FINDINGS

There are shared pathogenic mechanisms between pulmonary arterial hypertension (PAH) and group 3 pulmonary hypertension, including altered expression of mediators and growth factors implicated in both conditions. Factors such as hypoxia, hypoxemia, and hypercapnia also contribute to pulmonary vascular remodelling and endothelial dysfunction. However, the role of hypoxia as the sole driver of pulmonary hypertension in CLD is being reconsidered, particularly in chronic obstructive pulmonary disease (COPD), with evidence suggesting a potential role for cigarette smoke products in initiating pulmonary vascular impairment. On the other hand, interstitial lung disease (ILD) encompasses a group of heterogeneous lung disorders characterized by inflammation and fibrosis of the interstitium, leading to impaired gas exchange and progressive respiratory decline, which could also play a role as a cause of pulmonary hypertension.

SUMMARY

Understanding the intricate interplay between the pulmonary vascular compartment and the parenchymal and airway compartments in respiratory disease is crucial for developing effective diagnostic and therapeutic strategies for patients with PVD and CLD, with implications for both clinical practice and research.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Extracellular Water Ratio and Phase Angle as Predictors of Exacerbation in Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), characterized by high-energy metabolism, often leads to malnutrition and is linked to exacerbations. This study investigates the association of malnutrition-related body composition and handgrip strength changes with exacerbation frequencies in COPD patients.

METHODS

We analyzed 77 acute exacerbation COPD (AECOPD) patients and 82 stable COPD patients, categorized as frequent and infrequent exacerbators. Assessments included body composition, handgrip strength, nutritional risk, dyspnea scale, and COPD assessment.

RESULTS

Among AECOPD patients, there were 22 infrequent and 55 frequent exacerbators. Infrequent exacerbators showed better muscle parameters, extracellular water ratio, phase angle, and handgrip strength. Significant differences in intracellular water, total cellular water, protein, and body cell mass were observed between groups. Logistic regression indicated that extracellular water ratio (OR = 1.086) and phase angle (OR = 0.396) were independently associated with exacerbation risk. Thresholds for exacerbation risk were identified as 0.393 for extracellular water ratio and 4.85° for phase angle. In stable COPD, 13 frequent and 69 infrequent exacerbators were compared, showing no significant differences in weight, muscle, and adipose parameters, but significant differences in extracellular water ratio, phase angle, and handgrip strength.

CONCLUSIONS

These findings suggest that increased exacerbations in COPD patients correlate with higher extracellular water ratios and lower phase angles.

PD-1+ T lymphocyte proportions and hospitalized exacerbation of COPD: a prospective cohort study

OBJECTIVE

To evaluate the predictive value of PD-1 expression in T lymphocytes for rehospitalization due to acute exacerbations of COPD (AECOPD) in discharged patients.

METHODS

115 participants hospitalized with COPD (average age 71.8 ± 6.0 years) were recruited at Fujian Provincial Hospital. PD1+T lymphocytes proportions (PD1+T%), baseline demographics and clinical data were recorded at hospital discharge. AECOPD re-admission were collected at 1-year follow-up. Kaplan-Meier analysis compared the time to AECOPD readmissions among groups stratified by PD1+T%. Multivariable Cox proportional hazards regression and stratified analysis determined the correlation between PD1+T%, potential confounders, and AECOPD re-admission. ROC and DCA evaluated PD1+T% in enhancing the clinical predictive values of Cox models, BODE and CODEX.

RESULTS

68 participants (59.1%) were AECOPD readmitted, those with AECOPD readmission exhibited significantly elevated baseline PD-1+CD4+T/CD4+T% and PD-1+CD8 + T/CD8 + T% compared to non-readmitted counterparts. PD1+ T lymphocyte levels statistically correlated with BODE and CODEX indices. Kaplan-Meier analysis demonstrated that those in Higher PD1+ T lymphocyte proportions had reduced time to AECOPD readmission (logRank p < 0.05). Cox analysis identified high PD1+CD4+T and PD1+CD8+T ratios as risk factors of AECOPD readmission, with hazard ratios of 1.384(95%CI [1.043-1.725]) and 1.401(95%CI [1.013-1.789]), respectively. Notably, in patients aged < 70 years and with fewer than twice AECOPD episodes in the previous year, high PD1+T lymphocyte counts significantly increased risk for AECOPD readmission(p < 0.05). The AECOPD readmission predictive model, incorporating PD1+T% exhibited superior discrimination to the Cox model, BODE index and CODEX index, AUC of ROC were 0.763(95%CI [0.633-0.893]) and 0.734(95%CI [0.570-0.899]) (DeLong's test p < 0.05).The DCA illustrates that integrating PD1+T% into models significantly enhances the utility in aiding clinical decision-making.

CONCLUSION

Evaluation of PD1+ lymphocyte proportions offer a novel perspective for identifying high-risk COPD patients, potentially providing insights for COPD management.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR, URL: www.chictr.org.cn/ ), Registration number: ChiCTR2200055611 Date of Registration: 2022-01-14.

Phase 1 Study of MK-5475, an Inhaled Soluble Guanylate Cyclase Stimulator, in Participants with Pulmonary Hypertension Associated with Chronic Obstructive Pulmonary Disease

Purpose

This phase 1 study (NCT04370873) evaluated safety and pharmacokinetics/pharmacodynamics (PK/PD) of MK-5475 in participants with pulmonary hypertension associated with COPD (PH-COPD).

Methods

Eligible participants were 40-80 years old with COPD (FEV1/FVC <0.7; FEV1 >30% predicted) and PH (mean pulmonary arterial pressure ≥25 mmHg). Participants were randomized 2:1 to MK-5475 or placebo via dry-powder inhaler once daily for 7 days in Part 1 (360 µg) or 28 days in Part 2 (380 µg). Safety was assessed by adverse events (AEs) and arterial blood oxygenation. Part-2 participants had pulmonary vascular resistance (PVR; primary PD endpoint) and pulmonary blood volume (PBV; secondary PD endpoint) measured at baseline and Day 28. A non-informative prior was used to calculate posterior probability (PP) that the between-group difference (MK-5475 - placebo) in mean percent reduction from baseline in PVR was less than -15%.

Results

Nine participants were randomized in Part 1, and 14 participants in Part 2. Median age of participants (86.4% male) was 68.5 years (41-77 years); 95.5% had moderate-to-severe COPD. Incidences of AEs were comparable between MK-5475 and placebo: overall (5/14 [36%] versus 5/8 [63%]), drug-related (1/14 [7%] versus 2/8 [25%]), and serious (1/14 [7%] versus 1/8 [13%]). MK-5475 caused no meaningful changes in arterial blood oxygenation or PBV. MK-5475 versus placebo led to numerical improvements from baseline in PVR (-21.2% [95% CI: -35.4, -7.0] versus -5.4% [95% CI: -83.7, 72.9]), with between-group difference in PVR less than -15% and calculated PP of 51%.

Conclusion

The favorable safety profile and numerical reductions in PVR observed support further clinical development of inhaled MK-5475 for PH-COPD treatment.

Risk factors associated with pulmonary hypertension in patients with active tuberculosis and tuberculous destroyed lung: a retrospective study

Pulmonary tuberculosis (TB) can result in irreversible damage and lead to tuberculous destructive lung (TDL), a severe chronic lung disease that is associated with a high mortality rate. Additionally, pulmonary hypertension (PH) is a hemodynamic disorder that can be caused by lung diseases. The objective of this study is to investigate the risk factors associated with PH in active TB patients diagnosed with TDL. We conducted a retrospective review of the medical records of 237 patients who were diagnosed with TDL, active pulmonary tuberculosis, and underwent echocardiography at the Third People' Hospital of Shenzhen from January 1, 2016, to June 30, 2023. Univariate and multivariate logistic regression analyses were performed to identify factors that correlated with the development of pulmonary hypertension. Univariate and multivariate logistic regression analyses revealed that several factors were associated with an increased risk of pulmonary hypertension (PH) in individuals with tuberculosis destroyed lung (TDL). These factors included age (OR = 1.055), dyspnea (OR = 10.728), D-dimer (OR = 1.27), PaCO2 (OR = 1.040), number of destroyed lung lobes (OR = 5.584), bronchiectasis (OR = 3.205), and chronic pleuritis (OR = 2.841). When age, D-dimer, PaCO2, and number of destroyed lung lobes were combined, the predictive value for PH in patients with TDL was found to be 80.6% (95% CI 0.739-0.873),with a sensitivity of 76.6% and specificity of 73.2%. Advanced age, elevated D-dimer levels, hypercapnia, and severe lung damage were strongly correlated with the onset of PH in individuals with active pulmonary tuberculosis (PTB) and TDL. Furthermore, a model incorporating age, D-dimer, PaCO2, and the number of destroyed lung lobes might be valuable in predicting the occurrence of PH in patients with active PTB and TDL.

Prevalence of pulmonary hypertension in COPD patients living at high altitude

BACKGROUND

Pulmonary hypertension (PH) is associated with poor prognosis for patients with chronic obstructive pulmonary disease (COPD). Most of the knowledge about PH in COPD has been generated at sea level, with limited information associated with high altitude (HA).

OBJECTIVES

To assess the prevalence and severity of PH in COPD patients living in a HA city (2,640 m).

METHODS

Cross-sectional study in COPD patients with forced expiratory volume in the first second / forced vital capacity ratio (FEV1/FVC) post-bronchodilator <0,7. Transthoracic echocardiography (TTE), spirometry, carbon monoxide diffusing capacity, and arterial blood gasses tests were performed. Patients were classified according to the severity of airflow limitation. PH was defined by TTE as an estimated systolic pulmonary artery pressure (sPAP) > 36 mmHg or indirect PH signs; severe PH as sPAP > 60 mmHg; and disproportionate PH as an sPAP > 60 mmHg with non-severe airflow limitation (FEV1 > 50% predicted).

RESULTS

We included 176 COPD patients. The overall estimated prevalence of PH was 56.3% and the likelihood of having PH increased according to airflow-limitation severity: mild (31.6%), moderate (54.9%), severe (59.6%) and very severe (77.8%) (p = 0.038). The PH was severe in 7.3% and disproportionate in 3.4% of patients.

CONCLUSIONS

The estimated prevalence of PH in patients with COPD at HA is high, particularly in patients with mild to moderate airflow limitation, and greater than that described for COPD patients at low altitude. These results suggest a higher risk of developing PH for COPD patients living at HA compared to COPD patients with similar airflow limitation living at low altitude.

Heightened long-term cardiovascular risks after exacerbation of chronic obstructive pulmonary disease

OBJECTIVE

To examine the risk of adverse cardiovascular (CV) events following an exacerbation of chronic obstructive pulmonary disease (COPD).

METHODS

This retrospective cohort study identified patients with COPD using administrative data from Alberta, Canada from 2014 to 2019. Exposure periods were 12 months following moderate or severe exacerbations; the reference period was time preceding a first exacerbation. The primary outcome was the composite of all-cause death or a first hospitalisation for acute coronary syndrome, heart failure (HF), arrhythmia or cerebral ischaemia. Time-dependent Cox regression models estimated covariate-adjusted risks associated with six exposure subperiods following exacerbation.

RESULTS

Among 1 42 787 patients (mean age 68.1 years and 51.7% men) 61 981 (43.4%) experienced at least one exacerbation and 34 068 (23.9%) died during median follow-up of 64 months. The primary outcome occurred in 43 564 (30.5%) patients with an incidence rate prior to exacerbation of 5.43 (95% CI 5.36 to 5.50) per 100 person-years. This increased to 95.61 per 100 person-years in the 1-7 days postexacerbation (adjusted HR 15.86, 95% CI 15.17 to 16.58) and remained increased for up to 1 year. The risk of both the composite and individual CV events was increased following either a moderate or a severe exacerbation, though greater and more prolonged following severe exacerbation. The highest magnitude of increased risk was observed for HF decompensation (1-7 days, HR 72.34, 95% CI 64.43 to 81.22).

CONCLUSION

Moderate and severe COPD exacerbations are independent risk factors for adverse CV events, especially HF decompensation. The impact of optimising COPD management on CV outcomes should be evaluated.

Cardiovascular disease and risk in COPD: a state of the art review

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) and cardiovascular diseases (CVD) commonly co-exist. Outcomes of people living with both conditions are poor in terms of symptom burden, receiving evidence-based treatment and mortality. Increased understanding of the underlying mechanisms may help to identify treatments to relieve this disease burden. This narrative review covers the overlap of COPD and CVD with a focus on clinical presentation, mechanisms, and interventions. Literature up to December 2023 are cited.

AREAS COVERED

1. What is COPD 2. The co-existence of COPD and cardiovascular disease 3. Mechanisms of cardiovascular disease in COPD. 4. Populations with COPD are at risk of CVD 5. Complexity in the co-diagnosis of COPD in those with cardiovascular disease. 6. Therapy for COPD and implications for cardiovascular events and risk. 7. Cardiovascular risk and exacerbations of COPD. 8. Pro-active identification and management of CV risk in COPD.

EXPERT OPINION

The prospective identification of co-morbid COPD in CVD patients and of CVD and CV risk in people with COPD is crucial for optimizing clinical outcomes. This includes the identification of novel treatment targets and the design of clinical trials specifically designed to reduce the cardiovascular burden and mortality associated with COPD. Databases searched: Pubmed, 2006-2023.

Impact of inhalation exposure to cigarette smoke on the pathogenesis of pulmonary hypertension primed by monocrotaline in rats

Extensive, long-term exposure to cigarette smoke (CS) was recently suggested to be a risk factor for pulmonary hypertension, although further validation is required. The vascular effects of CS share similarities with the etiology of pulmonary hypertension, including vascular inflammation and remodeling. Thus, we examined the influence of CS exposure on the pathogenesis of monocrotaline (MCT)-induced pulmonary hypertension, hypothesizing that smoking might accelerate the development of primed pulmonary hypertension. CS was generated from 3R4F reference cigarettes, and rats were exposed to CS by inhalation at total particulate matter concentrations of 100-300 μg/L for 4 h/day, 7 days/week for 4 weeks. Following 1 week of initial exposure, rats received 60 mg/kg MCT and were sacrificed and analyzed after an additional 3 weeks of exposure. MCT induced hypertrophy in pulmonary arterioles and increased the Fulton index, a measure of right ventricular hypertrophy. Additional CS exposure exacerbated arteriolar hypertrophy but did not further elevate the Fulton index. No significant alterations were observed in levels of endothelin-1 and vascular endothelial growth factor, or in hematological and serum biochemical parameters. Short-term inhalation exposure to CS exacerbated arteriolar hypertrophy in the lung, although this effect did not directly aggravate the overworked heart under the current experimental conditions.

Blood Pressure Estimation Based on PPG and ECG Signals Using Knowledge Distillation

OBJECTIVE

Easy access bio-signals are useful for alleviating the shortcomings and difficulties associated with cuff-based and invasive blood pressure (BP) measurement techniques. This study proposes a deep learning model, trained using knowledge distillation, based on photoplethysmographic (PPG) and electrocardiogram (ECG) signals to estimate systolic and diastolic blood pressures.

METHODS

The estimation model comprises convolutional layers followed by one bidirectional recurrent layer and attention layers. The training approach involves knowledge distillation, where a smaller model (student model) is trained by leveraging information from a larger model (teacher model).

RESULTS

The proposed multistage model was evaluated on 1205 subjects from Medical Information Mart for Intensive Care (MIMIC) III database using the Association for the Advancement of Medical Instrumentation (AAMI) and the standards of the British Hypertension Society (BHS). The results revealed that our model performance achieved grade A in estimating both systolic blood pressure (SBP) and diastolic blood pressure (DBP) and met the requirements of the AAMI standard. After training with knowledge distillation (KD), the model achieved a mean absolute error and standard deviation of 2.94 ± 5.61 mmHg for SBP and 2.02 ± 3.60 mmHg for DBP.

CONCLUSION

Our results demonstrate the benefits of the knowledge distillation training method in reducing the number of parameters and improving the predictive accuracy of the blood pressure regression model.

MCJ: A mitochondrial target for cardiac intervention in pulmonary hypertension

Pulmonary hypertension (PH) can affect both pulmonary arterial tree and cardiac function, often leading to right heart failure and death. Despite the urgency, the lack of understanding has limited the development of effective cardiac therapeutic strategies. Our research reveals that MCJ modulates mitochondrial response to chronic hypoxia. MCJ levels elevate under hypoxic conditions, as in lungs of patients affected by COPD, mice exposed to hypoxia, and myocardium from pigs subjected to right ventricular (RV) overload. The absence of MCJ preserves RV function, safeguarding against both cardiac and lung remodeling induced by chronic hypoxia. Cardiac-specific silencing is enough to protect against cardiac dysfunction despite the adverse pulmonary remodeling. Mechanistically, the absence of MCJ triggers a protective preconditioning state mediated by the ROS/mTOR/HIF-1α axis. As a result, it preserves RV systolic function following hypoxia exposure. These discoveries provide a potential avenue to alleviate chronic hypoxia-induced PH, highlighting MCJ as a promising target against this condition.

Fibroblast growth factor 10 reverses cigarette smoke- and elastase-induced emphysema and pulmonary hypertension in mice

BACKGROUND

COPD is an incurable disease and a leading cause of death worldwide. In mice, fibroblast growth factor (FGF)10 is essential for lung morphogenesis, and in humans, polymorphisms in the human FGF10 gene correlate with an increased susceptibility to develop COPD.

METHODS

We analysed FGF10 signalling in human lung sections and isolated cells from healthy donor, smoker and COPD lungs. The development of emphysema and PH was investigated in Fgf10+/- and Fgfr2b+/- (FGF receptor 2b) mice upon chronic exposure to cigarette smoke. In addition, we overexpressed FGF10 in mice following elastase- or cigarette smoke-induced emphysema and pulmonary hypertension (PH).

RESULTS

We found impaired FGF10 expression in human lung alveolar walls and in primary interstitial COPD lung fibroblasts. In contrast, FGF10 expression was increased in large pulmonary vessels in COPD lungs. Consequently, we identified impaired FGF10 signalling in alveolar walls as an integral part of the pathomechanism that leads to emphysema and PH development: mice with impaired FGF10 signalling (Fgf10+/- and Fgfr2b+/- ) spontaneously developed lung emphysema, PH and other typical pathomechanistic features that generally arise in response to cigarette smoke exposure.

CONCLUSION

In a therapeutic approach, FGF10 overexpression successfully restored lung alveolar and vascular structure in mice with established cigarette smoke- and elastase-induced emphysema and PH. FGF10 treatment triggered an initial increase in the number of alveolar type 2 cells that gradually returned to the basal level when the FGF10-mediated repair process progressed. Therefore, the application of recombinant FGF10 or stimulation of the downstream signalling cascade might represent a novel therapeutic strategy in the future.

Role of prostanoids, nitric oxide and endothelin pathways in pulmonary hypertension due to COPD

Pulmonary hypertension (PH) due to chronic obstructive pulmonary disease (COPD) is classified as Group 3 PH, with no current proven targeted therapies. Studies suggest that cigarette smoke, the most risk factor for COPD can cause vascular remodelling and eventually PH as a result of dysfunction and proliferation of pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs). In addition, hypoxia is a known driver of pulmonary vascular remodelling in COPD, and it is also thought that the presence of hypoxia in patients with COPD may further exaggerate cigarette smoke-induced vascular remodelling; however, the underlying cause is not fully understood. Three main pathways (prostanoids, nitric oxide and endothelin) are currently used as a therapeutic target for the treatment of patients with different groups of PH. However, drugs targeting these three pathways are not approved for patients with COPD-associated PH due to lack of evidence. Thus, this review aims to shed light on the role of impaired prostanoids, nitric oxide and endothelin pathways in cigarette smoke- and hypoxia-induced pulmonary vascular remodelling and also discusses the potential of using these pathways as therapeutic target for patients with PH secondary to COPD.

Pulmonary Hypertension: Unveiling Molecular Mechanisms, Diagnosis, and Therapeutic Targets

Pulmonary hypertension (PH) is a progressive and life-threatening disease characterized by increased pulmonary arterial pressure, which leads to right heart hypertrophy and eventually right heart failure [...].

The vascular perspective on acute and chronic lung disease

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

CEACAM6 as a Novel Therapeutic Target to Boost HO-1-mediated Antioxidant Defense in COPD

Rationale: Tobacco smoking and air pollution are primary causes of chronic obstructive pulmonary disease (COPD). However, only a minority of smokers develop COPD. The mechanisms underlying the defense against nitrosative/oxidative stress in nonsusceptible smokers to COPD remain largely unresolved. Objectives: To investigate the defense mechanisms against nitrosative/oxidative stress that possibly prevent COPD development or progression. Methods: Four cohorts were investigated: 1) sputum samples (healthy, n = 4; COPD, n = 37), 2) lung tissue samples (healthy, n = 13; smokers without COPD, n = 10; smoker+COPD, n = 17), 3) pulmonary lobectomy tissue samples (no/mild emphysema, n = 6), and 4) blood samples (healthy, n = 6; COPD, n = 18). We screened 3-nitrotyrosine (3-NT) levels, as indication of nitrosative/oxidative stress, in human samples. We established a novel in vitro model of a cigarette smoke extract (CSE)-resistant cell line and studied 3-NT formation, antioxidant capacity, and transcriptomic profiles. Results were validated in lung tissue, isolated primary cells, and an ex vivo model using adeno-associated virus-mediated gene transduction and human precision-cut lung slices. Measurements and Main Results: 3-NT levels correlate with COPD severity of patients. In CSE-resistant cells, nitrosative/oxidative stress upon CSE treatment was attenuated, paralleled by profound upregulation of heme oxygenase-1 (HO-1). We identified carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) as a negative regulator of HO-1-mediated nitrosative/oxidative stress defense in human alveolar type 2 epithelial cells (hAEC2s). Consistently, inhibition of HO-1 activity in hAEC2s increased the susceptibility toward CSE-induced damage. Epithelium-specific CEACAM6 overexpression increased nitrosative/oxidative stress and cell death in human precision-cut lung slices on CSE treatment. Conclusions: CEACAM6 expression determines the hAEC2 sensitivity to nitrosative/oxidative stress triggering emphysema development/progression in susceptible smokers.

Nicotine promotes e-cigarette vapour-induced lung inflammation and structural alterations

BACKGROUND

Electronic cigarette (e-cigarette) vapour is gaining popularity as an alternative to tobacco smoking and can induce acute lung injury. However, the specific role of nicotine in e-cigarette vapour and its long-term effects on the airways, lung parenchyma and vasculature remain unclear.

RESULTS

In vitro exposure to nicotine-containing e-cigarette vapour extract (ECVE) or to nicotine-free e-cigarette vapour extract (NF ECVE) induced changes in gene expression of epithelial cells and pulmonary arterial smooth muscle cells (PASMCs), but ECVE in particular caused functional alterations (e.g. a decrease in human and mouse PASMC proliferation by 29.3±5.3% and 44.3±8.4%, respectively). Additionally, acute inhalation of nicotine-containing e-cigarette vapour (ECV) but not nicotine-free e-cigarette vapour (NF ECV) increased pulmonary endothelial permeability in isolated lungs. Long-term in vivo exposure of mice to ECV for 8 months significantly increased the number of inflammatory cells, in particular lymphocytes, compared to control and NF ECV in the bronchoalveolar fluid (BALF) (ECV: 853.4±150.8 cells·mL-1; control: 37.0±21.1 cells·mL-1; NF ECV: 198.6±94.9 cells·mL-1) and in lung tissue (ECV: 25.7±3.3 cells·mm-3; control: 4.8±1.1 cells·mm-3; NF ECV: 14.1±2.2 cells·mm-3). BALF cytokines were predominantly increased by ECV. Moreover, ECV caused significant changes in lung structure and function (e.g. increase in airspace by 17.5±1.4% compared to control), similar to mild tobacco smoke-induced alterations, which also could be detected in the NF ECV group, albeit to a lesser degree. In contrast, the pulmonary vasculature was not significantly affected by ECV or NF ECV.

CONCLUSIONS

NF ECV components induce cell type-specific effects and mild pulmonary alterations, while inclusion of nicotine induces significant endothelial damage, inflammation and parenchymal alterations.

FVC/DLCO identifies pulmonary hypertension and predicts 5-year all-cause mortality in patients with COPD

BACKGROUND

Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD). However, it is unknown whether the ratio of forced vital capacity (FVC) to diffusing lung capacity for carbon monoxide (D_LCO) can identify PH in the patients with COPD and predict its prognosis.

METHODS

The study population I included 937 COPD patients who were admitted to inpatient treatments from 2010 to 2017, and finally 750 patients were available to follow-up the 5-year all-cause mortality (study population II). Clinical characteristics of the study population were recorded.

RESULTS

COPD patients with PH had a higher FVC/D_LCO value compared with the patients without PH. The threshold for FVC/D_LCO to identify PH in COPD patients was 0.44 l/mmol/min/kPa. Multivariate logistic regression analysis showed that FVC/D_LCO was a significant predictor for PH in the patients with COPD. The study population II showed that the 5-year all-cause mortality of COPD patients was significantly higher in combined with PH group than without PH group. Compared with the survivor group, FVC/D_LCO value was significantly increased in non-survivor group. The threshold for FVC/D_LCO to predict 5-year all-cause mortality was 0.41 l/mmol/min/kPa. Kaplan-Meier survival curves showed that 5-year cumulative survival rate for COPD patients were significantly decreased when the value of FVC/D_LCO was ≥ 0.41 l/mmol/min/kPa. Multivariate cox regression analysis showed that FVC/D_LCO was an independent prognostic factor for 5-year all-cause mortality in COPD patients.

CONCLUSION

FVC/D_LCO could identify PH in the patients with COPD and was an independent predictor for 5-year all-cause mortality of COPD.

Combined Pulmonary Fibrosis and Emphysema: When Scylla and Charybdis Ally

Combined pulmonary fibrosis and emphysema (CPFE) is a recently recognized syndrome that, as its name indicates, involves the existence of both interstitial lung fibrosis and emphysema in one individual, and is often accompanied by pulmonary hypertension. This debilitating, progressive condition is most often encountered in males with an extensive smoking history, and is presented by dyspnea, preserved lung volumes, and contrastingly impaired gas exchange capacity. The diagnosis of the disease is based on computed tomography imaging, demonstrating the coexistence of emphysema and interstitial fibrosis in the lungs, which might be of various types and extents, in different areas of the lung and several relative positions to each other. CPFE bears high mortality and to date, specific and efficient treatment options do not exist. In this review, we will summarize current knowledge about the clinical attributes and manifestations of CPFE. Moreover, we will focus on pathophysiological and pathohistological lung phenomena and suspected etiological factors of this disease. Finally, since there is a paucity of preclinical research performed for this particular lung pathology, we will review existing animal studies and provide suggestions for the development of additional in vivo models of CPFE syndrome.

Perioperative fluid management for lung transplantation is challenging

Lung transplantation is the definitive end-stage treatment for many lung diseases, and postoperative pulmonary oedema severely affects survival after lung transplantation. Optimizing perioperative fluid management can reduce the incidence of postoperative pulmonary oedema and improve the prognosis of lung transplant patients by removing the influence of patient, donor's lung and ECMO factors. Therefore, this article reviews seven aspects of lung transplant patients' pathophysiological characteristics, physiological characteristics of fluids, the influence of the donor lung on pulmonary oedema as well as current fluid rehydration concepts, advantages or disadvantages of intraoperative monitoring tools or types of fluids on postoperative pulmonary oedema, while showing the existing challenges in section 7. The aim is to show the specificity of perioperative fluid management in lung transplant patients and to provide new ideas for individualised fluid management in lung transplantation.

The association between pulmonary artery enlargement and mortality in an Emergency Department population undergoing computed tomography pulmonary angiography

Findings of an enlarged pulmonary artery diameter (PAd) and increased pulmonary artery to ascending aorta ratio (PA:AA) on contrast-enhanced computed tomography pulmonary angiography (CTPA) are associated with increased mortality in particular groups of patients with cardiopulmonary disease. However, the frequency and prognostic significance of these incidental findings has not been studied in unselected patients evaluated in the Emergency Department (ED). This study aims to determine the prevalence and associated prognosis of enlarged pulmonary artery measurements in an ED cohort. We measured PA and AA diameters on 990 CTPA studies performed in the ED. An enlarged PA diameter was defined as >27 mm in females and >29 mm in males, while an increased PA:AA was defined as >0.9. Poisson regression was performed to calculate prevalence ratios for relevant comorbidities, and multivariable Cox regression was performed to calculate hazard ratios (HR) for mortality of patients with enlarged pulmonary artery measurements. An enlarged PAd was observed in 27.9% of 990 patients and was more commonly observed in older patients and in patients with obesity or heart failure. Conversely, PA:AA was increased in 34.2% of subjects, and was more common in younger patients and those with peripheral vascular disease or obesity. After controlling for age, sex, and comorbidities, both enlarged PAd (HR 1.29, 95% CI 1.00-1.68, p = 0.05) and PA:AA (HR 1.70, 95% CI 1.31-2.22 p < 0.01) were independently associated with mortality. In sum, enlarged PAd and increased PA:AA are common in patients undergoing CTPAs in the ED setting and both are independently associated with mortality.

Endotyping COPD: hypoxia-inducible factor-2 as a molecular "switch" between the vascular and airway phenotypes?

COPD is a heterogeneous disease with multiple clinical phenotypes. COPD endotypes can be determined by different expressions of hypoxia-inducible factors (HIFs), which, in combination with individual susceptibility and environmental factors, may cause predominant airway or vascular changes in the lung. The pulmonary vascular phenotype is relatively rare among COPD patients and characterised by out-of-proportion pulmonary hypertension (PH) and low diffusing capacity of the lung for carbon monoxide, but only mild-to-moderate airway obstruction. Its histologic feature, severe remodelling of the small pulmonary arteries, can be mediated by HIF-2 overexpression in experimental PH models. HIF-2 is not only involved in the vascular remodelling but also in the parenchyma destruction. Endothelial cells from human emphysema lungs express reduced HIF-2α levels, and the deletion of pulmonary endothelial Hif-2α leads to emphysema in mice. This means that both upregulation and downregulation of HIF-2 have adverse effects and that HIF-2 may represent a molecular "switch" between the development of the vascular and airway phenotypes in COPD. The mechanisms of HIF-2 dysregulation in the lung are only partly understood. HIF-2 levels may be controlled by NAD(P)H oxidases via iron- and redox-dependent mechanisms. A better understanding of these mechanisms may lead to the development of new therapeutic targets.

Tensions in Taxonomies: Current Understanding and Future Directions in the Pathobiologic Basis and Treatment of Group 1 and Group 3 Pulmonary Hypertension

In the over 100 years since the recognition of pulmonary hypertension (PH), immense progress and significant achievements have been made with regard to understanding the pathophysiology of the disease and its treatment. These advances have been mostly in idiopathic pulmonary arterial hypertension (IPAH), which was classified as Group 1 Pulmonary Hypertension (PH) at the Second World Symposia on PH in 1998. However, the pathobiology of PH due to chronic lung disease, classified as Group 3 PH, remains poorly understood and its treatments thus remain limited. We review the history of the classification of the five groups of PH and aim to provide a state-of-the-art review of the understanding of the pathogenesis of Group 1 PH and Group 3 PH including insights gained from novel high-throughput omics technologies that have revealed heterogeneities within these categories as well as similarities between them. Leveraging the substantial gains made in understanding the genomics, epigenomics, proteomics, and metabolomics of PAH to understand the full spectrum of the complex, heterogeneous disease of PH is needed. Multimodal omics data as well as supervised and unbiased machine learning approaches after careful consideration of the powerful advantages as well as of the limitations and pitfalls of these technologies could lead to earlier diagnosis, more precise risk stratification, better predictions of disease response, new sub-phenotype groupings within types of PH, and identification of shared pathways between PAH and other types of PH that could lead to new treatment targets. © 2023 American Physiological Society. Compr Physiol 13:4295-4319, 2023.

iNOS Deletion in Alveolar Epithelium Cannot Reverse the Elastase-Induced Emphysema in Mice

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. In addition to chronic bronchitis and emphysema, patients often develop at least mild pulmonary hypertension (PH). We previously demonstrated that inhibition of inducible nitric oxide synthase (iNOS) prevents and reverses emphysema and PH in mice. Interestingly, strong iNOS upregulation was found in alveolar epithelial type II cells (AECII) in emphysematous murine lungs, and peroxynitrite, which can be formed from iNOS-derived NO, was shown to induce AECII apoptosis in vitro. However, the specific cell type(s) that drive(s) iNOS-dependent lung regeneration in emphysema/PH has (have) not been identified yet.

AIM

we tested whether iNOS knockout in AECII affects established elastase-induced emphysema in mice.

METHODS

four weeks after a single intratracheal instillation of porcine pancreatic elastase for the induction of emphysema and PH, we induced iNOS knockout in AECII in mice, and gave an additional twelve weeks for the potential recovery.

RESULTS

iNOS knockout in AECII did not reduce elastase-induced functional and structural lung changes such as increased lung compliance, decreased mean linear intercept and increased airspace, decreased right ventricular function, increased right ventricular systolic pressure and increased pulmonary vascular muscularization. In vitro, iNOS inhibition did not reduce apoptosis of AECII following exposure to a noxious stimulus.

CONCLUSION

taken together, our data demonstrate that iNOS deletion in AECII is not sufficient for the regeneration of emphysematous murine lungs, and suggest that iNOS expression in pulmonary vascular or stromal cells might be critically important in this regard.

Quinazoline-based human phosphodiesterase 5 inhibitors exhibited a selective vasorelaxant effect on rat isolated pulmonary arteries involving NO-sGC-cGMP pathway and calcium inhibitory effects

Phosphodiesterase 5 (PDE5) inhibitors are an attractive option among the currently available therapies in the management of pulmonary arterial hypertension (PAH). Good selectivity for PDE5 is associated with reduced side effects and greater vasorelaxant effect on pulmonary arteries (PA). This study investigated the vasorelaxant effects of a series of quinazoline-based PDE5 inhibitors and their precise mechanisms action using rat isolated PA and aorta, as compared to sildenafil. Their effects on rat hepatocytes (viability and CYP activities) were also evaluated. Compounds 5 and 11 displayed lower human PDE5 IC₅₀ of the analogs studied here and induced a greater relaxant effect on PA (EC₅₀ 0.94 ± 0.30 and 1.03 ± 0.23 μM, respectively). As compared to sildenafil (EC₅₀ = 0.05 ± 0.02 μM on PA), the relaxant effect of 5 and 11 on PA was lower but their selectivity for PA compared to aorta was higher. The effects of 5 and 11 were reduced by N^G-nitro-L-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one, but not by indomethacin or potassium channels blockers. They also enhanced the relaxant effect of sodium nitroprusside, and inhibited extracellular Ca²⁺ influx and intracellular Ca²⁺release. Compounds 5 and 11 did not reduce hepatocyte viability except at concentration > 10 μM, inhibited CYP3A at 10 μM, like sildenafil, but did not induce CYP1A. In conclusion, this study identified 2 quinazoline analogues with good PDE5 inhibitory activity and good selectivity for the pulmonary vasculature. Their relaxant effect involves both the potentiation of nitric oxide-sGC-cGMP pathway and calcium inhibition. These compounds are potential leads for developing new drugs for PAH.

CircGSAP regulates the cell cycle of pulmonary microvascular endothelial cells via the miR-942-5p sponge in pulmonary hypertension

Background We recently demonstrated that circGSAP was diminished in lung tissues from patients with pulmonary arterial hypertension and in hypoxia-induced pulmonary microvascular endothelial cells (PMECs). However, the underlying role of circGSAP in PMECs remains unknown. The study aimed to investigate the contribution of circGSAP to proliferation, apoptosis and cell cycle of PMECs in hypoxic environment and explore the mechanism.

Methods The expression of circGSAP was quantified by real-time PCR or immunofluorescence in human lung tissue and PMECs. CircGSAP plasmid, circGSAP small interfering RNA (siRNA), miRNA inhibitor and target gene siRNA were synthesized to verify the role of circGSAP on regulating the proliferation, apoptosis, and cell cycle of PMECs.

Results CircGSAP levels were decreased in lungs and plasma of patients with pulmonary hypertension second to chronic obstructive pulmonary disease (COPD-PH) and were associated with poor outcomes of COPD-PH patients. Upregulation of circGSAP inhibited proliferation, apoptosis resistance and G1/S transition of PMECs. Dual luciferase reporter assays showed that circGSAP acted as a competitive endogenous RNA regulating miR-942-5p, and identified SMAD4 as a target gene of miR-942-5p, Then, we verified the functions of miR-942-5p and SMAD4 in PMECs. In addition, the effect of circGSAP siRNA on PMECs was mitigated by transfection of miR-942-5p inhibitor, and the effect of miR-942-5p inhibitor on PMECs was inhibited by SMAD4 siRNA.

Conclusion Our findings demonstrated that diminished circGSAP accelerated cell cycle to facilitate cell proliferation and apoptosis resistance through competitively binding miR-942-5p to modulate SMAD4 expressions in hypoxia-induced PMECs, indicating potential therapeutic strategies for PH.

Spanish COPD Guideline (GesEPOC) Update: Comorbidities, Self-Management and Palliative Care

The current health care models described in GesEPOC indicate the best way to make a correct diagnosis, the categorization of patients, the appropriate selection of the therapeutic strategy and the management and prevention of exacerbations. In addition, COPD involves several aspects that are crucial in an integrated approach to the health care of these patients. The evaluation of comorbidities in COPD patients represents a healthcare challenge. As part of a comprehensive assessment, the presence of comorbidities related to the clinical presentation, to some diagnostic technique or to some COPD-related treatments should be studied. Likewise, interventions on healthy lifestyle habits, adherence to complex treatments, developing skills to recognize the signs and symptoms of exacerbation, knowing what to do to prevent them and treat them within the framework of a self-management plan are also necessary. Finally, palliative care is one of the pillars in the comprehensive treatment of the COPD patient, seeking to prevent or treat the symptoms of a disease, the side effects of treatment, and the physical, psychological and social problems of patients and their caregivers. Therefore, the main objective of this palliative care is not to prolong life expectancy, but to improve its quality. This chapter of GesEPOC 2021 presents an update on the most important comorbidities, self-management strategies, and palliative care in COPD, and includes a recommendation on the use of opioids for the treatment of refractory dyspnea in COPD.

Myeloid-cell-specific deletion of inducible nitric oxide synthase protects against smoke-induced pulmonary hypertension in mice

BACKGROUND

Pulmonary hypertension (PH) is a common complication of COPD, associated with increased mortality and morbidity. Intriguingly, pulmonary vascular alterations have been suggested to drive emphysema development. Previously, we identified inducible nitric oxide synthase (iNOS) as an essential enzyme for development and reversal of smoke-induced PH and emphysema, and showed that iNOS expression in bone-marrow-derived cells drives pulmonary vascular remodelling, but not parenchymal destruction. In this study, we aimed to identify the iNOS-expressing cell type driving smoke-induced PH and to decipher pro-proliferative pathways involved.

METHODS

To address this question we used 1) myeloid-cell-specific iNOS knockout mice in chronic smoke exposure and 2) co-cultures of macrophages and pulmonary artery smooth muscle cells (PASMCs) to decipher underlying signalling pathways.

RESULTS

Myeloid-cell-specific iNOS knockout prevented smoke-induced PH but not emphysema in mice. Moreover, iNOS deletion in myeloid cells ameliorated the increase in expression of CD206, a marker of M2 polarisation, on interstitial macrophages. Importantly, the observed effects on lung macrophages were hypoxia-independent, as these mice developed hypoxia-induced PH. In vitro, smoke-induced PASMC proliferation in co-cultures with M2-polarised macrophages could be abolished by iNOS deletion in phagocytic cells, as well as by extracellular signal-regulated kinase inhibition in PASMCs. Crucially, CD206-positive and iNOS-positive macrophages accumulated in proximity of remodelled vessels in the lungs of COPD patients, as shown by immunohistochemistry.

CONCLUSION

In summary, our results demonstrate that iNOS deletion in myeloid cells confers protection against PH in smoke-exposed mice and provide evidence for an iNOS-dependent communication between M2-like macrophages and PASMCs in underlying pulmonary vascular remodelling.

Clinical Value of FeNO for Pulmonary Hypertension Diagnosis in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

To investigate the clinical value of fractional exhaled nitric oxide (FeNO) in the diagnosis of pulmonary hypertension (PH) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

In this study, the medical records of AECOPD patients were retrospectively reviewed. The patients were divided into AECOPD and AECOPD + PH groups based on the absence or presence of PH. Moreover, FeNO and other indexes were compared between the two groups. The value of FeNO in diagnosing AECOPD with PH was determined using the ROC curve.

Results

A total of 83 patients were enrolled (56 in the AECOPD group and 27 in the AECOPD + PH group). The level of FeNO was significantly lower in the AECOPD + PH group than in the AECOPD group (P = 0.022). Moreover, FeNO level (25.22 ± 8.45 ppb) was higher in the mild PH subgroup than in the moderate (16.64 ± 5.67 ppb, P = 0.005) or severe (11.75 ± 2.36, P = 0.002) PH subgroups. FeNO level was positively correlated with C-reactive protein in AECOPD patients while negatively correlated with brain natriuretic peptide in the AECOPD + PH group. ROC analysis showed that the optimal cutoff value of FeNO in the diagnosis of AECOPD with PH was 24.5 ppb.

Conclusion

FeNO level at admission can act as an indicator for PH diagnosis in AECOPD patients.

SMAD3 rs36221701 T>C polymorphism impacts COPD susceptibility in the Kashi population

Small mother against decapentaplegic (SMAD) family member 3 (SMAD3) is well correlated with the inflammatory response of chronic obstructive pulmonary disease (COPD). A previous study indicated that the single nucleotide polymorphism (SNP) rs36221701 of SMAD3 was related to the risk of inflammatory disease. Hence, given the pathogenesis of COPD is intently associated with smoking and gene polymorphism, this study aims to analyze the relationship between SMAD3 rs36221701 and COPD susceptibility, and to explore whether the interaction is related to smoking status. We studied the association between the rs36221701 and rs34307601 of SMAD3 and COPD susceptibility, a total of 541 COPD patients and 534 controls of the Uyghur population were recruited at the First People's Hospital and the village of Kashi. The interrelation of the two SNPs with the risk of COPD was determined by calculating odds ratio (OR) and 95% confidence interval (95% CI). We found a significant association between the rs36221701 and COPD risk in the non-smoking population. TC genotype showed a significant decreased association with COPD risk (OR = 0.59, 95% CI = 0.41-0.83, P < 0.05), but CC genotype can increased the COPD risk (OR > 1, P < 0.05). In addition, COPD susceptibility was not related to the genetic variations in the rs34307601 (P > 0.05). In conclusion, we confirmed that the SMAD3 rs36221701 may be associated with COPD susceptibility in the Chinese Uyghur population, especially among non-smokers. Our data provide new light for the relationship between SMAD3 gene polymorphisms and COPD susceptibility in the Chinese Uyghur population.

Precision and Advanced Nano-Phytopharmaceuticals for Therapeutic Applications

Phytopharmaceuticals have been widely used globally since ancient times and acknowledged by healthcare professionals and patients for their superior therapeutic value and fewer side-effects compared to modern medicines. However, phytopharmaceuticals need a scientific and methodical approach to deliver their components and thereby improve patient compliance and treatment adherence. Dose reduction, improved bioavailability, receptor selective binding, and targeted delivery of phytopharmaceuticals can be likely achieved by molding them into specific nano-formulations. In recent decades, nanotechnology-based phytopharmaceuticals have emerged as potential therapeutic candidates for the treatment of various communicable and non-communicable diseases. Nanotechnology combined with phytopharmaceuticals broadens the therapeutic perspective and overcomes problems associated with plant medicine. The current review highlights the therapeutic application of various nano-phytopharmaceuticals in neurological, cardiovascular, pulmonary, and gastro-intestinal disorders. We conclude that nano-phytopharmaceuticals emerge as promising therapeutics for many pathological conditions with good compliance and higher acceptance.

Treatment of pulmonary hypertension associated with COPD: a systematic review

Chronic obstructive pulmonary disease-associated pulmonary hypertension (COPD-PH) is an increasingly recognised condition which contributes to worsening dyspnoea and poor survival in COPD. It is uncertain whether specific treatment of COPD-PH, including use of medications approved for pulmonary arterial hypertension (PAH), improves clinical outcomes. This systematic review and meta-analysis assesses potential benefits and risks of therapeutic options for COPD-PH.

We searched Medline and Embase for relevant publications until September 2020. Articles were screened for studies on treatment of COPD-PH for at least 4 weeks in 10 or more patients. Screening, data extraction, and risk of bias assessment were performed independently in duplicate. When possible, relevant results were pooled using the random effects model.

Supplemental long-term oxygen therapy (LTOT) mildly reduced mean pulmonary artery pressure (PAP), slowed progression of PH, and reduced mortality, but other clinical or functional benefits were not assessed. Phosphodiesterase type 5 inhibitors significantly improved systolic PAP (pooled treatment effect −5.9 mmHg; 95% CI −10.3, −1.6), but had inconsistent clinical benefits. Calcium channel blockers and endothelin receptor antagonists had limited haemodynamic, clinical, or survival benefits. Statins had limited clinical benefits despite significantly lowering systolic PAP (pooled treatment effect −4.6 mmHg; 95% CI −6.3, −2.9).

This review supports guideline recommendations for LTOT in hypoxaemic COPD-PH patients as well as recommendations against treatment with PAH-targeted medications. Effective treatment of COPD-PH depends upon research into the pathobiology and future high-quality studies comprehensively assessing clinically relevant outcomes are needed.

The presence of PH in COPD patients is associated with worsening morbidity and mortality. These findings support guideline recommendations for LTOT in hypoxaemic COPD-PH patients as well as recommendations against treatment using PAH-targeted medications.https://bit.ly/3Al4rLb

The efficacy and safety of high-flow nasal cannula therapy in patients with COPD and type II respiratory failure: a meta-analysis and systematic review

Background

High-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) have been used for the treatment of COPD and respiratory failure in clinical settings. We aimed to evaluate the efficacy and safety of HFNC therapy in patients with COPD and type II respiratory failure, to provide evidence to the clinical COPD management.

Methods

We searched Cochrane et al. databases up to Dec 31, 2020 for randomized controlled trials (RCTs) on the use of HFNC therapy in patients with COPD and type II respiratory failure. Two researchers independently screened the literature according to the inclusion and exclusion criteria, and evaluated the quality of the literature and extracted data. We used Revman5.3 software for statistical analysis of collected data.

Results

A total of 6 RCTs involving 525 COPD and type II respiratory failure patients. Meta-analyses indicated that compared with NIV, HFNC could significantly reduce PaCO₂ level (MD = − 2.64, 95% CI (− 3.12 to − 2.15)), length of hospital stay ((MD = – 1.19, 95 CI (− 2.23 to − 0.05)), the incidence of nasal facial skin breakdown ((OR = 0.11, 95% CI (0.03–0.41)). And there were no significant differences between the two groups in PaO₂ ((MD = 2.92, 95% CI (− 0.05 to 5.90)), incidence of tracheal intubation ((OR = 0.74, 95% CI (0.34–1.59)) and mortality (OR = 0.77, 95% CI (0.28–2.11)).

Conclusions

HFNC is more advantageous over NIV in the treatment of COPD and type II respiratory failure. Future studies with larger sample size and strict design are needed to further elucidate the role of HFNC in COPD and respiratory failure.

[Chronic obstructive pulmonary disease, sleep-disordered breathing and hypoventilation-Influence on the cardiorenal system]

Comorbidities are frequently observed in patients suffering from pulmonary diseases due to shared risk factors and intricate interactions between various organ systems. This article aims to characterize the effects of selected diseases of the respiratory system on the cardiovascular system and kidneys. Advanced chronic obstructive pulmonary disease (COPD) often leads to a prognostically unfavorable increased pressure in the pulmonary circulation. In this respect treatment of these patients is primarily aimed at the underlying pulmonary disease and targeted treatment of the pulmonary hypertension should only be carried out according to invasive diagnostics and in an individualized manner. So far, the fact that there is a substantial overlap between COPD and heart failure with preserved ejection fraction has been completely ignored, which should be considered in the diagnostic procedure. Obstructive sleep apnea (OSA) has several unfavorable effects on the cardiovascular system and has been identified as an independent risk factor for cardiovascular diseases. The established treatment of OSA with continuous positive airway pressure (CPAP) has been shown to improve daytime sleepiness and the quality of life; however, an effect of CPAP on the occurrence of cardiovascular events, especially in asymptomatic patients, has so far not been demonstrated in randomized trials. Peripheral edema is frequently observed in patients suffering from chronic hypercapnia, which can be explained by several pathophysiological mechanisms, including pulmonary vasoconstriction and a direct effect of the hypercapnia on renal blood flow. Apart from the administration of diuretics, recompensation of such patients always requires treatment of the hypercapnia by noninvasive ventilation.

Identification of novel metabolic signatures potentially involved in the pathogenesis of COPD associated pulmonary hypertension

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) associated pulmonary hypertension (COPD-PH), one of the most prevalent forms of PH, is a major burden on the healthcare system. Although PH in COPD is usually of mild-to-moderate severity, its presence is associated with shorter survival, more frequent exacerbations and worse clinical outcomes. The pathophysiologic mechanisms responsible for PH development in COPD patients remain unclear. It is envisioned that a better understanding of the underlying mechanism will help in diagnosis and future treatment strategies.

OBJECTIVES

The present study aims to determine metabolomic alterations in COPD-PH patients as compared to healthy controls. Additionally, to ensure that the dysregulated metabolites arise due to the presence of PH per se, an independent COPD cohort is included for comparison purposes.

METHODS

Paired serum and exhaled breath condensate (EBC) samples were collected from male patients with COPD-PH (n = 60) in accordance with the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines. Age, sex and BMI matched healthy controls (n = 57) and COPD patients (n = 59) were recruited for comparison purposes. All samples were characterized using ¹H nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

Fifteen serum and 9 EBC metabolites were found to be significantly altered in COPD-PH patients as compared to healthy controls. Lactate and pyruvate were dysregulated in both the biofluids and were further correlated with echocardiographic systolic pulmonary artery pressure (sPAP). Multivariate analysis showed distinct class separation between COPD-PH and COPD.

CONCLUSIONS

The findings of this study indicate an increased energy demand in patients with COPD-PH. Furthermore, both lactate and pyruvate correlate with sPAP, indicating their importance in the clinical course of the disease.

Epigenetic Regulation by Suv4-20h1 in Cardiopulmonary Progenitor Cells is Required to Prevent Pulmonary Hypertension and COPD

Background: The etiology of life-threatening cardiopulmonary diseases such as Pulmonary Hypertension (PH) and Chronic Obstructive Pulmonary Disease (COPD) originates from a complex interplay of environmental factors and genetic predispositions, which is not fully understood. Likewise, little is known about developmental abnormalities or epigenetic dysregulations that might predispose for PH or COPD in adult individuals. Methods: To identify pathology-associated epigenetic alteration in diseased lung tissues, we screened a cohort of human PH and COPD patients for changes of histone modifications by immunofluorescence staining. To analyze the function of H4K20me2/3 in lung pathogenesis, we developed a series of Suv4-20h1 knockout mouse lines targeting cardiopulmonary progenitor cells (CPPs) and different heart and lung cell types, followed by hemodynamic studies and morphometric assessment of tissue samples. Molecular, cellular and biochemical techniques were applied to analyze the function of Suv4-20h1-dependent epigenetic processes in cardiopulmonary progenitor cells and their derivatives. Results: We discovered a strong reduction of the histone modifications H4K20me2/3 in human COPD but not PH patients, which depend on the activity of the H4K20 di-methyltransferase SUV4-20H1. Loss of Suv4-20h1 in CPPs caused a COPD-like/PH phenotype in mice including formation of perivascular tertiary lymphoid tissue and goblet cell hyperplasia, hyper-proliferation of smooth muscle cells/myofibroblasts, impaired alveolarization and maturation defects of the microvasculature leading to massive right ventricular dilatation and premature death. Mechanistically, SUV4-20H1 binds directly to the 5'-upstream regulatory element of superoxide dismutase 3 (Sod3) gene to repress its expression. Increased levels of the extracellular SOD3 enzyme in Suv4-20h1 mutants increases hydrogen peroxide (H2O2) concentrations, causing vascular defects and impairing alveolarization. Conclusions: Our findings reveal a pivotal role of the histone modifier SUV4-20H1 in cardiopulmonary co-development and uncover developmental origins of cardiopulmonary diseases. We assume that the study will facilitate the understanding of pathogenic events causing PH and COPD, and aid the development of epigenetic drugs for treatment of cardiopulmonary diseases.

Effect of pulmonary hypertension on exercise tolerance in patients with COPD: a prognostic systematic review and meta-analysis

Background

Pulmonary hypertension (PH) is a frequent complication in patients with COPD.

Objective

To determine if, in patients with COPD, the presence of PH decreases exercise tolerance.

Methods

We included studies that analysed exercise tolerance using a cardiopulmonary exercise test (CPET) in patients with COPD with PH (COPD-PH) and without PH (COPD-nonPH). Two independent reviewers analysed the studies, extracted the data and assessed the quality of the evidence.

Results

Of the 4915 articles initially identified, seven reported 257 patients with COPD-PH and 404 patients with COPD-nonPH. The COPD-PH group showed differences in peak oxygen consumption (V′_O2peak), −3.09 mL·kg⁻¹·min⁻¹ (95% CI −4.74 to −1.43, p=0.0003); maximum workload (W_max), −20.5 W (95% CI −34.4 to −6.5, p=0.004); and oxygen pulse (O₂ pulse), −1.24 mL·beat⁻¹ (95% CI −2.40 to −0.09, p=0.03), in comparison to the group with COPD-nonPH. If we excluded studies with lung transplant candidates, the sensitivity analyses showed even bigger differences: V′_O2, −4.26 mL·min⁻¹·kg⁻¹ (95% CI −5.50 to −3.02 mL·kg⁻¹·min⁻¹, p<0.00001); W_max, −26.6 W (95% CI −32.1 to −21.1 W, p<0.00001); and O₂ pulse, −2.04 mL·beat⁻¹ (95% CI −2.92 to −1.15 mL·beat⁻¹, p<0.0001).

Conclusion

Exercise tolerance was significantly lower in patients with COPD-PH than in patients with COPD-nonPH, particularly in nontransplant candidates.

The V′_O2peak, Wmax and O₂ pulse values were significantly lower in patients with COPD-PH than in patients with COPD-nonPH, particularly in nontransplant candidateshttps://bit.ly/3s5dtJ9

The effect of long-term doxycycline treatment in a mouse model of cigarette smoke-induced emphysema and pulmonary hypertension

Chronic obstructive pulmonary disease (COPD) is a major cause of death and a still incurable disease, comprising emphysema and chronic bronchitis. In addition to airflow limitation, patients with COPD can suffer from pulmonary hypertension (PH). Doxycycline, an antibiotic from the tetracycline family, in addition to its pronounced antimicrobial activity, acts as a matrix metalloproteinase (MMP) inhibitor and has anti-inflammatory properties. Furthermore, doxycycline treatment exhibited a beneficial effect in several preclinical cardiovascular disease models. In preclinical research, doxycycline is frequently employed for gene expression modulation in Tet-On/Tet-Off transgenic animal models. Therefore, it is crucial to know whether doxycycline treatment in Tet-On/Tet-Off systems has effects independent of gene expression modulation by such systems. Against this background, we assessed the possible curative effects of long-term doxycycline administration in a mouse model of chronic CS exposure. Animals were exposed to cigarette smoke (CS) for 8 mo and then subsequently treated with doxycycline for additional 3 mo in room air conditions. Doxycycline decreased the expression of MMPs and general pro-inflammatory markers in the lungs from CS-exposed mice. This downregulation was, however, insufficient to ameliorate CS-induced emphysema or PH. Tet-On/Tet-Off induction by doxycycline in such models is a feasible genetic approach to study curative effects at least in established CS-induced emphysema and PH. However, we report several parameters that are influenced by doxycycline and use of a Tet-On/Tet-Off system when evaluating those parameters should be interpreted with caution.

Animal models of pulmonary hypertension: Getting to the heart of the problem

Despite recent therapeutic advances, pulmonary hypertension (PH) remains a fatal disease due to the development of right ventricular (RV) failure. At present, no treatments targeted at the right ventricle are available, and RV function is not widely considered in the preclinical assessment of new therapeutics. Several small animal models are used in the study of PH, including the classic models of exposure to either hypoxia or monocrotaline, newer combinational and genetic models, and pulmonary artery banding, a surgical model of pure RV pressure overload. These models reproduce selected features of the structural remodelling and functional decline seen in patients and have provided valuable insight into the pathophysiology of RV failure. However, significant reversal of remodelling and improvement in RV function remains a therapeutic obstacle. Emerging animal models will provide a deeper understanding of the mechanisms governing the transition from adaptive remodelling to a failing right ventricle, aiding the hunt for druggable molecular targets.

The Challenge to Decide between Pulmonary Hypertension Due to Chronic Lung Disease and PAH with Chronic Lung Disease

Chronic lung diseases are strongly associated with pulmonary hypertension (PH), and even mildly elevated pulmonary arterial pressures are associated with increased mortality. Chronic obstructive pulmonary disease (COPD) is the most common chronic lung disease, but few of these patients develop severe PH. Not all these pulmonary pressure elevations are due to COPD, although patients with severe PH due to COPD may represent the largest subgroup within patients with COPD and severe PH. There are also patients with left heart disease (group 2), chronic thromboembolic disease (group 4, CTEPH) and pulmonary arterial hypertension (group 1, PAH) who suffer from COPD or another chronic lung disease as co-morbidity. Because therapeutic consequences very much depend on the cause of pulmonary hypertension, it is important to complete the diagnostic procedures and to decide on the main cause of PH before any decision on PAH drugs is made. The World Symposia on Pulmonary Hypertension (WSPH) have provided guidance for these important decisions. Group 2 PH or complex developmental diseases with elevated postcapillary pressures are relatively easy to identify by means of elevated pulmonary arterial wedge pressures. Group 4 PH can be identified or excluded by perfusion lung scans in combination with chest CT. Group 1 PAH and Group 3 PH, although having quite different disease profiles, may be difficult to discern sometimes. The sixth WSPH suggests that severe pulmonary hypertension in combination with mild impairment in the pulmonary function test (FEV1 > 60 and FVC > 60%), mild parenchymal abnormalities in the high-resolution CT of the chest, and circulatory limitation in the cardiopulmonary exercise test speak in favor of Group 1 PAH. These patients are candidates for PAH therapy. If the patient suffers from group 3 PH, the only possible indication for PAH therapy is severe pulmonary hypertension (mPAP ≥ 35 mmHg or mPAP between 25 and 35 mmHg together with very low cardiac index (CI) < 2.0 L/min/m²), which can only be derived invasively. Right heart catheter investigation has been established nearly 100 years ago, but there are many important details to consider when reading pulmonary pressures in spontaneously breathing patients with severe lung disease. It is important that such diagnostic procedures and the therapeutic decisions are made in expert centers for both pulmonary hypertension and chronic lung disease.

Updated Perspectives on Pulmonary Hypertension in COPD

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

Cancer and pulmonary hypertension: Learning lessons and real-life interplay

This article reviews the scientific reasons that support the intriguing vision of pulmonary hypertension (PH) as a disease with a cancer-like nature and to understand whether this point of view may have fruitful consequences for the overall management of PH. This review compares cancer and PH in view of Hanahan and Weinberg’s principles (i.e., hallmarks of cancer) with an emphasis on hyperproliferative, metabolic, and immune/inflammatory aspects of the disease. In addition, this review provides a perspective on the role of transcription factors and chromatin and epigenetic aberrations, besides genetics, as “common driving mechanisms” of PH hallmarks and the foreseeable use of transcription factor/epigenome targeting as multitarget approach against the hallmarks of PH. Thus, recognition of the widespread applicability and analogy of these concepts will increasingly affect the development of new means of PH treatment.

Insights into Chronic Obstructive Pulmonary Disease as Critical Risk Factor for Cardiovascular Disease

In patients with chronic obstructive pulmonary disease (COPD), cardiovascular comorbidities are highly prevalent and associated with considerable morbidity and mortality. This coincidence is increasingly seen in the context of a “cardiopulmonary continuum” rather than being simply attributed to shared risk factors, in particular, cigarette smoking. Both disease entities are centrally linked to systemic inflammation as well as aging, arterial stiffness, and several common biomarkers that led to the development of pulmonary hypertension, left ventricular diastolic dysfunction, atherosclerosis, and reduced physical activity and exercise capacity. For these reasons, COPD should be considered an independent factor of high cardiovascular risk, and efforts should be directed to early identification of cardiovascular disease (CVD) in COPD patients. Assessment of the overall cardiovascular risk is especially important in patients with severe exacerbation episodes, and the same therapeutic target levels for glycosylated hemoglobin, low-density lipoprotein cholesterol (LDL-C), or blood pressure than those recommended by clinical practice guidelines for patients at high cardiovascular risk, should be achieved. In this review, we will discuss the most recent evidence of the role of COPD as a critical cardiovascular risk factor and try to find new insights and potential prevention strategies for this disease.