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

Changes in Retinal Nerve Fiber Layer Thickness in Patients With Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study is to evaluate the relationship between retinal nerve fiber layer (RNFL) thickness and the onset as well as progression of chronic obstructive pulmonary disease (COPD).

METHODS

Database searches were conducted in PubMed, Embase, Cochrane Library, Web of Science, CNKI, WanFang Data, VIP Database, and CBM, covering the period from each database's inception to March 2024.

RESULTS

This meta-analysis included 15 studies from 2016 to 2023, comprising a total of 1455 participants (801 in the COPD group and 654 in the health group). The results showed a significant reduction in RNFL thickness across all quadrants (average, inferior, nasal, superior, and temporal) in the COPD group compared to the health group (MD: -4.46; 95%CI: -7.77 to -1.14; p = 0.008; MD: -8.17; 95%CI: -11.36 to -4.99; p < 0.00001; MD: -4.69; 95%CI: -7.22 to -2.16; p = 0.0003; MD: -4.83; 95%CI: -8.45 to -1.21; p = 0.009; MD: -2.89; 95%CI: -5.35 to -0.43; p = 0.02). In the mild/moderate COPD group, only the inferior RNFL (MD: -2.32; 95%CI: -4.40 to -0.24; p = 0.03) showed a significant reduction. However, in the severe COPD group, all quadrants were significantly reduced (MD: -5.89; 95%CI: -7.40 to -4.38; p < 0.0001; MD: -6.74; 95%CI: -10.71 to -2.77; p = 0.0009; MD: -4.29; 95%CI: -5.95 to -2.64; p < 0.0001; MD: -2.34; 95%CI: -4.30 to -0.37; p = 0.02; MD: -4.84; 95%CI: -8.82 to -0.86; p = 0.02).

CONCLUSION

Based on current evidence, the average RNFL thickness and the thicknesses of various RNFL regions in COPD patients are significantly lower than those in healthy subjects, and these reductions are closely associated with disease severity. The inferior RNFL may be the first to show changes with the onset and progression of COPD.

Pulmonary hypertension associated with COPD: a phenotype analysis

Background

Pulmonary hypertension (PH) associated with COPD (PH-COPD) exhibits diverse phenotypes, challenging therapeutic management. This study aimed to describe the characteristics of COPD patients with distinct phenotypes, namely end-stage COPD with or without PH (group 1), other COPD patients with mild-to-moderate pre-capillary PH-COPD (group 2) and COPD patients with a pulmonary vascular phenotype (PVP) (group 3).

Methods

We performed a retrospective analysis of COPD patients who underwent right heart catheterisation from 2015 to 2022.

Results

81 patients were included in group 1, 37 in group 2 and 35 in group 3. The groups differed in terms of clinical, functional, haemodynamic and imaging characteristics. Group 1 had significantly marked lung hyperinflation with increased total lung capacity and residual volume, a feature not observed in group 3. These results were confirmed by analysis of chest CT scans, which confirmed varying degrees of emphysema, as follows: severe in group 1, moderate in group 2 and mild in group 3, with median total emphysema indices of 55% (48-62), 32% (16-49) and 16% (3.4-31), respectively, p<0.0001.

Conclusions

Our results highlight the broad spectrum of PH in COPD, from PH associated with end-stage COPD (phenotype/group 1), characterised by predominant alveolar wall damage with severe emphysema, to PVP (phenotype/group 3), mainly due to pulmonary vascular changes. Phenotype/group 2 represents an intermediate state combining features of both. In the current debate on how to distinguish PH-COPD phenotypes, it might be of interest to include quantitative thresholds for emphysema in future diagnostic and management algorithms.

Targeting HIF-2α: the role of belzutifan in clear cell renal carcinoma management

INTRODUCTION

Belzutifan is a first-in-class hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor. It targets the von Hippel-Lindau protein (pVHL)-HIF-vascular endothelial growth factor (VEGF) pathway, which is crucial in cellular responses to hypoxia. By inhibiting HIF-2α, belzutifan disrupts the transcription of genes involved in tumor growth and angiogenesis.

AREAS COVERED

In this review, we describe the pVHL-HIF-VEGF pathway and how it led to the development of HIF inhibitors, including belzutifan. A search was conducted for trials involving Belzutifan, including phase I-III trials. We describe the relevant toxicity, with emphasis on hypoxia and anemia.

EXPERT OPINION

Belzutifan is a relatively safe drug, with manageable adverse events, including anemia and hypoxia as on-target toxicity. Ongoing trials are studying its benefit in overall survival for RCC in first-line treatment and its potential in other malignancies. The LITESPARK-005 trial reported the benefit of belzutifan in progression-free survival (PFS) compared to everolimus in later lines of treatment, with improvement in quality-of-life outcomes. Given its different mechanism of action to currently available treatments, belzutifan is expected to play a prominent role in the treatment of clear cell renal carcinoma and other cancers.

Clinical effectiveness and safety of dupilumab in patients with chronic obstructive pulmonary disease: A 7-year population-based cohort study

BACKGROUND

Previous randomized controlled trials have established the efficacy of dupilumab among patients with chronic obstructive pulmonary disease (COPD) treated with triple therapy over 52 weeks of follow-up.

OBJECTIVE

This population-based cohort study aimed to explore the long-term safety and effectiveness of dupilumab in patients with COPD.

METHODS

The study included US patients with COPD who were seen between April 2017 and August 2024. Patients initiating dupilumab and therapies that incorporated long-acting β2-agonist (LABA) inhalers were included. Patients with asthma or lung cancer were excluded. The risk of outcomes occurring after initiation of dupilumab versus LABA-containing therapies was measured. For detailed methods, please see the Methods section in this article's Online Repository at www.jacionline.org.

RESULTS

A total of 1521 dupilumab initiators and 1521 propensity score-matched patients who were receiving LABA-based therapies were included. Receiving dupilumab was associated with lower all-cause mortality (hazard ratio [HR] = 0.53, 95% CI = 0.43-0.65), fewer emergency department visits (HR = 0.78, 95% CI = 0.69-0.89), and lower acute exacerbation rates (HR = 0.59, 95% CI = 0.53-0.65). Dupilumab was also associated with reductions in the requirement for short-acting β2-agonists (HR = 0.48, 95% CI = 0.43-0.52) and short-acting muscarinic antagonists (HR = 0.43, 95% CI = 0.37-0.49) for symptom control. Additionally, dupilumab decreased rates of subsequent pneumonia (HR = 0.65, 95% CI = 0.50-0.86), and COPD-relevant comorbidities, including new-onset heart failure (HR = 0.69, 95% CI = 0.53-0.90) and new-onset anxiety (HR = 0.70, 95% CI =0.53-0.93).

CONCLUSIONS

In patients with COPD, dupilumab was associated with a lower mortality rate, fewer emergency department visits, and a reduced risk of acute exacerbations, respiratory symptoms, and respiratory infections. More studies are needed to validate the efficacy of dupilumab among patients with COPD of various severities.

Pulmonary veno-occlusive disease: a clinical review

Pulmonary vasculopathy presents as a spectrum of diseases affecting the precapillary pulmonary arterioles, the capillaries and the venules. Pulmonary veno-occlusive disease (PVOD) is classified under group 1 pulmonary arterial hypertension (PAH) as subgroup 1.5 (PAH with features of capillary/venous involvement), and represents a progressive and fatal spectrum of pulmonary vascular disorders. PVOD and pulmonary capillary haemangiomatosis (PCH) can be clinically indistinguishable and often coexist, along with the same risk factors and genetic alterations; they are referred to together as PVOD/PCH in the literature. For brevity, we use the clinical term PVOD in this article. PVOD cannot be distinguished from other forms of PAH based on symptoms and haemodynamics. Risk factors include exposure to toxins/chemotherapeutic drugs and genetic mutation in the EIF2AK4 gene. Radiographic features such as mediastinal adenopathy, centrilobular ground-glass opacities, and interlobular septal thickening, along with the presence of hypoxia and reduced diffusion capacity of the lung may be required for a clinical diagnosis of PVOD, as lung biopsy carries a high risk for bleeding. Characteristic histological findings include narrowing/occlusion of small pulmonary veins. The development of pulmonary oedema with pulmonary vasodilator therapy limits therapeutic options for PVOD. With limited treatment options, lung transplantation remains the only curative treatment.

Targeting organ-specific mitochondrial dysfunction to improve biological aging

In an aging society, unveiling new anti-aging strategies to prevent and combat aging-related diseases is of utmost importance. Mitochondria are the primary ATP production sites and key regulators of programmed cell death. Consequently, these highly dynamic organelles play a central role in maintaining tissue function, and mitochondrial dysfunction is a pivotal factor in the progressive age-related decline in cellular homeostasis and organ function. The current review examines recent advances in understanding the interplay between mitochondrial dysfunction and organ-specific aging. Thereby, we dissect molecular mechanisms underlying mitochondrial impairment associated with the deterioration of organ function, exploring the role of mitochondrial DNA, reactive oxygen species homeostasis, metabolic activity, damage-associated molecular patterns, biogenesis, turnover, and dynamics. We also highlight emerging therapeutic strategies in preclinical and clinical tests that are supposed to rejuvenate mitochondrial function, such as antioxidants, mitochondrial biogenesis stimulators, and modulators of mitochondrial turnover and dynamics. Furthermore, we discuss potential benefits and challenges associated with the use of these interventions, emphasizing the need for organ-specific approaches given the unique mitochondrial characteristics of different tissues. In conclusion, this review highlights the therapeutic potential of addressing mitochondrial dysfunction to mitigate organ-specific aging, focusing on the skin, liver, lung, brain, skeletal muscle, and lung, as well as on the reproductive, immune, and cardiovascular systems. Based on a comprehensive understanding of the multifaceted roles of mitochondria, innovative therapeutic strategies may be developed and optimized to combat biological aging and promote healthy aging across diverse organ systems.

Phenotypes in pulmonary hypertension

The clinical classification of pulmonary hypertension (PH) has guided diagnosis and treatment of patients with PH for several decades. Discoveries relating to underlying mechanisms, pathobiology and responses to treatments for PH have informed the evolution in this clinical classification to describe the heterogeneity in PH phenotypes. In more recent years, advances in imaging, computational science and multi-omic approaches have yielded new insights into potential phenotypes and sub-phenotypes within the existing clinical classification. Identification of novel phenotypes in pulmonary arterial hypertension (PAH) with unique molecular profiles, for example, could lead to new precision therapies. Recent phenotyping studies have also identified groups of patients with PAH that more closely resemble patients with left heart disease (group 2 PH) and lung disease (group 3 PH), which has important prognostic and therapeutic implications. Within group 2 and group 3 PH, novel phenotypes have emerged that reflect a persistent and severe pulmonary vasculopathy that is associated with worse prognosis but still distinct from PAH. In group 4 PH (chronic thromboembolic pulmonary disease) and sarcoidosis (group 5 PH), the current approach to patient phenotyping integrates clinical, haemodynamic and imaging characteristics to guide treatment but applications of multi-omic approaches to sub-phenotyping in these areas are sparse. The next iterations of the PH clinical classification are likely to reflect several emerging PH phenotypes and improve the next generation of prognostication tools and clinical trial design, and improve treatment selection in clinical practice.

A preclinical animal study to evaluate the operability and safety of domestic one-way endobronchial valves

Purpose

To evaluate the operability and safety of bronchoscopic domestic one-way endobronchial valves (EBV) on animals.

Methods

Nine pigs were randomly assigned (2:1) to receive domestic one-way EBV (the experimental group, n = 6) and Zephyr® EBV (the control group, n = 3). Routine blood tests, arterial blood gases, and CT scans of the lungs were performed 1 day pre-procedure in addition to 1 week and 1 month post-procedure to assess changes in blood markers and lung volumes. At 1 month post-procedure, the animals were sacrificed, followed by removal of all valves via bronchoscopy. Pathological examinations of critical organs were subsequently performed.

Results

A total of 15 valves were placed in the experimental group and 6 valves were placed in the control group, without serious complications. Routine blood tests and arterial blood gas examinations at 1 day pre-procedure, 1 week post-procedure, and 1 month post-procedure did not differ significantly in both groups. No EBV displacement was noted under bronchoscopy, and the valve was smoothly removable by bronchoscope at 1 month post-procedure. At 1 week post-procedure, varying degrees of target lung lobe volume reduction were observed on lung CT in both groups. Lung volume reduction was achieved at 1 month post-procedure in both groups, without significant statistical difference. Although 3 cases in the experimental group and 1 case in the control group developed varying degrees of pneumonia, the inflammatory response did not increase over time during the experimental period. Pathological examination revealed no significant abnormal changes in the critical organs for both groups.

Conclusion

Our results demonstrate that domestic EBV is safe and reliable for endobronchial application in general-grade laboratory white pigs. The safety of domestic EBV is similar to that of Zephyr® EBV, with good ease of use and operability. This kind of domestic EBV can meet the safety evaluation requirements for animal testing.

Different Transcriptome Features of Peripheral Blood Mononuclear Cells in Non-Emphysematous Chronic Obstructive Pulmonary Disease

Non-emphysematous chronic obstructive pulmonary disease (COPD), which is defined based on chest computed tomography findings, presented different transcriptome features of peripheral blood mononuclear cells (PBMCs) compared with emphysematous COPD. Enrichment analysis of transcriptomic data in COPD demonstrated that the "Hematopoietic cell lineage" pathway in Kyoto Encyclopedia of Genes and Genomes pathway analysis was highly upregulated, suggesting that cellular dynamic dysregulation in COPD lungs is affected by pathologically modified PBMCs. The differentially expressed genes (DEGs) upregulated in PBMCs reflected the disease state of non-emphysematous COPD. Upregulated DEGs such as XCL1, PRKCZ, TMEM102, CD200R1, and AQP1 activate T lymphocytes and eosinophils. Upregulating keratan sulfate biosynthesis and metabolic processes is associated with protection against the destruction of the distal airways. ITGA3 upregulation augments interactions with extracellular matrix proteins, and COL6A1 augments the profibrotic mast cell phenotype during alveolar collagen VI deposition. Upregulating HSPG2, PDGFRB, and PAK4 contributes to the thickening of the airway wall, and upregulating SERPINF1 expression explains the better-preserved vascular bed. Therefore, gene expression and pathway analysis in PBMCs in patients with non-emphysematous COPD represented type 2 immune responses and airway remodeling features. Therefore, these patients have asthmatic potential despite no clinical signs of asthma, in contrast to those with emphysematous COPD.

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

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

Expression of HIF-1α in pediatric asthmatic patients

Background

Several studies have suggested that HIF-1α regulates eosinophil activity and induces epithelial inflammation via NF-κB activation in the pathophysiology of asthma. The purpose of this study was to examine the expression of the transcription factors HIF-1α and nuclear HIF in mononuclear cells obtained from peripheral blood samples of healthy pediatric patients, asthmatic patients, and asthmatic exacerbations, regardless of disease severity.

Methods

HIF-1 levels were measured using immunocytochemistry in 133 patients aged 6 to 17 years in this crosssectional and comparative study. A microscope was used to examine glass slides, and positive cells were counted in four fields per slide using an image analyzer.

Results

HIF-1α and nuclear HIF levels were significantly higher in asthma patients and even higher in patients experiencing asthma attacks (p<0.0001, 95% CI). There was no significant difference in the percentage of HIF-1α expression between groups with intermittent asthma and those with mild persistent asthma, nor between patients with asthma and those experiencing asthma exacerbations.

Conclusions

When compared to healthy individuals, the expression of nuclear HIF and HIF-1α is increased in peripheral mononuclear cells in asthma patients and even more so in asthma exacerbations. This suggests that HIF-1α is important in the pathogenesis of this disease.