Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder that may lead to gas exchange abnormalities, including hypercapnia. Chronic hypercapnia is an independent risk factor of mortality in COPD, leading to epithelial dysfunction and impaired lung immunity. Moreover, chronic hypercapnia affects the cardiovascular physiology, increases the risk of cardiovascular morbidity and mortality, and promotes muscle wasting and musculoskeletal abnormalities. Noninvasive ventilation is a widely used technique to remove carbon dioxide, and several studies have investigated its role in COPD. In the present review, we aim to summarize the causes and effects of chronic hypercapnia in COPD. Furthermore, we discuss the use of domiciliary noninvasive ventilation as a treatment option for hypercapnia while highlighting the controversies within the evidence. Finally, we provide some insightful clinical recommendations and draw attention to possible future research areas.

Clinical trials evaluating the management of acute exacerbations of COPD assess heterogeneous outcomes, often omitting those that are clinically relevant or more important to patients. We have developed a core outcome set, a consensus-based minimum set of important outcomes that we recommend are evaluated in all future clinical trials on exacerbations management, to improve their quality and comparability. COPD exacerbations outcomes were identified through methodological systematic reviews and qualitative interviews with 86 patients from 11 countries globally. The most critical outcomes were prioritised for inclusion in the core outcome set through a two-round Delphi survey completed by 1063 participants (256 patients, 488 health professionals and 319 clinical academics) from 88 countries in five continents. Two global, multi-stakeholder, virtual consensus meetings were conducted to 1) finalise the core outcome set and 2) prioritise a single measurement instrument to be used for evaluating each of the prioritised outcomes. Consensus was informed by rigorous methodological systematic reviews. The views of patients with COPD were accounted for at all stages of the project. Survival, treatment success, breathlessness, quality of life, activities of daily living, the need for a higher level of care, arterial blood gases, disease progression, future exacerbations and hospital admissions, treatment safety and adherence were all included in the core outcome set. Focused methodological research was recommended to further validate and optimise some of the selected measurement instruments. The panel did not consider the prioritised set of outcomes and associated measurement instruments to be burdensome for patients and health professionals to use.

Chronic obstructive pulmonary disease (COPD) is related to endothelial dysfunction and the impaired generation of nitric oxide (NO) from L-arginine by the endothelial NO synthase (eNOS). The relationship between eNOS dysfunctionality and airway inflammation is unknown. We assessed serum asymmetric and symmetric dimethylarginine (ADMA and SDMA) and nitrite/nitrate concentrations, indicators of eNOS function, in patients with COPD and correlated them with markers of inflammation. We recruited 15 control smokers, 29 patients with stable and 32 patients with exacerbated COPD requiring hospitalization (20 of them were measured both at admission and discharge). Serum L-arginine, ADMA, SDMA, nitrite and nitrate were measured and correlated with airway inflammatory markers (fractional exhaled nitric oxide concentration - FENO, sputum nitrite and nitrate, sputum cellularity), serum C-reactive protein - CRP, white blood cell count, lung function and blood gases. ANOVA, t-tests and Pearson correlation were used (mean ± SD or geometric mean ± geometric SD for nitrite/nitrate). Serum L-arginine/ADMA, a marker of substrate availability for eNOS, was lower in stable (214 ± 58, p < 0.01) and exacerbated COPD (231 ± 68, p < 0.05) than in controls (287 ± 64). The serum concentration of SDMA, a competitor of L-arginine transport, was elevated during an exacerbation (0.78 ± 0.39 μM) compared to stable patients (0.53 ± 0.14 μM, p < 0.01) and controls (0.45 ± 0.14 μM, p < 0.001). ADMA correlated with blood neutrophil percentage (r = 0.36, p < 0.01), FENO (r = 0.42, p < 0.01) and a tendency for positive association was observed to sputum neutrophil count (r = 0.33, p = 0.07). SDMA correlated with total sputum inflammatory cell count (r = 0.61, p < 0.01) and sputum neutrophil count (r = 0.62, p < 0.01). Markers were not related to lung function, blood gases or CRP. L-arginine/ADMA was unchanged, but serum SDMA level decreased (0.57 ± 0.42 μM, p < 0.05) after systemic steroid treatment of the exacerbation. Serum nitrite level increased in stable and exacerbated disease (4.11 ± 2.12 and 4.03 ± 1.77 vs. control: 1.61 ± 1.84 μM, both p < 0.001). Our data suggest impaired eNOS function in stable COPD, which is transiently aggravated during an exacerbation and partly reversed by systemic steroid treatment. Serum ADMA and SDMA correlate with airway inflammatory markers implying a possible effect of anti-inflammatory therapy on endothelial dysfunction. Serum nitrite can serve as a compensatory pool for impaired endothelial NO generation.

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Many lines of evidence suggest that the disturbances in circadian rhythm are responsible for the development of CVDs; however, circadian misalignment is not yet a treatable trait in clinical practice. The circadian rhythm is controlled by the central clock located in the suprachiasmatic nucleus and clock genes (molecular clock) located in all cells. Dyslipidaemia and vascular inflammation are two hallmarks of atherosclerosis and numerous experimental studies conclude that they are under direct influence by both central and molecular clocks. This review will summarise the results of experimental studies on lipid metabolism, vascular inflammation and circadian rhythm, and translate them into the pathophysiology of atherosclerosis and cardiovascular disease. We discuss the effect of time-respected administration of medications in cardiovascular medicine. We review the evidence on the effect of bright light and melatonin on cardiovascular health, lipid metabolism and vascular inflammation. Finally, we suggest an agenda for future research and recommend on clinical practice.

Background and objective: The relationship between hospitalisation with an eosinophilic acute exacerbation of COPD (AE-COPD) and future relapses is unclear. We aimed to explore this association by following 152 patients for 12 months after hospital discharge or until their first moderate or severe flare-up.Methods: Patients hospitalised with AE-COPD were divided into eosinophilic and non-eosinophilic groups based on full blood count results on admission. All patients were treated with a course of systemic corticosteroid. The Cox proportional hazards model was used to study the association with the time to first re-exacerbation; a generalised linear regression model was applied to identify clinical variables related to the recurrence of relapses.Results: We did not find a difference in the time to the next moderate or severe exacerbation between the eosinophilic (≥2% of total leukocytes and/or ≥200 eosinophils·µL⁻¹, n=51, median (interquartile range): 21 (10–36) weeks) and non-eosinophilic groups (n=101, 17 (9–36) weeks, log-rank test: p=0.63). No association was found when other cut-off values (≥3% of total leukocytes and/or ≥300 eosinophils·µL⁻¹) were used for the eosinophilic phenotype. However, the higher number of past severe exacerbations, a lower forced expiratory volume in 1 s (FEV₁) at discharge and higher pack-years were related to shorter exacerbation-free time. According to a subgroup analysis (n=73), 48.1% of patients with initial eosinophilic exacerbations had non-eosinophilic relapses on readmission.Conclusions: Our data do not support an increased risk of earlier recurring moderate or severe relapses in patients hospitalised with eosinophilic exacerbations of COPD. Eosinophilic severe exacerbations present a variable phenotype.

The human body contains a very complex and dynamic ecosystem of bacteria. The bacteriome interacts with the host bi-directionally, and changes in either factor impact the entire system. It has long been known that chronic airway diseases are associated with disturbances in the lung bacteriome. However, less is known about the role of gut bacteriome in the most common respiratory diseases. Here, we aim to summarise the evidence concerning the role of the intestinal bacteriome in the pathogenesis and disease course of bronchial asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea. Furthermore, we discuss the consequences of an altered gut bacteriome on the most common comorbidities of these lung diseases. Lastly, we also reflect on the therapeutic potential of influencing the gut microbiome to improve disease outcomes.