Annual FEV1 changes and numbers of circulating endothelial microparticles in patients with COPD: a prospective study

Pulmonary Vascular Dysfunctions in Cystic Fibrosis

Cystic fibrosis (CF) is an inherited disorder caused by a deleterious mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Given that the CFTR protein is a chloride channel expressed on a variety of cells throughout the human body, mutations in this gene impact several organs, particularly the lungs. For this very reason, research regarding CF disease and CFTR function has historically focused on the lung airway epithelium. Nevertheless, it was discovered more than two decades ago that CFTR is also expressed and functional on endothelial cells. Despite the great strides that have been made in understanding the role of CFTR in the airway epithelium, the role of CFTR in the endothelium remains unclear. Considering that the airway epithelium and endothelium work in tandem to allow gas exchange, it becomes very crucial to understand how a defective CFTR protein can impact the pulmonary vasculature and overall lung function. Fortunately, more recent research has been dedicated to elucidating the role of CFTR in the endothelium. As a result, several vascular dysfunctions associated with CF disease have come to light. Here, we summarize the current knowledge on pulmonary vascular dysfunctions in CF and discuss applicable therapies.

Seminar: Extracellular Vesicles as Mediators of Environmental Stress in Human Disease

BACKGROUND

Extracellular vesicles (EVs), membrane-bound particles containing a variety of RNA types, DNA, proteins, and other macromolecules, are now appreciated as an important means of communication between cells and tissues, both in normal cellular physiology and as a potential indicator of cellular stress, environmental exposures, and early disease pathogenesis. Extracellular signaling through EVs is a growing field of research for understanding fundamental mechanisms of health and disease and for the potential for biomarker discovery and therapy development. EVs are also known to play important roles in mediating the effects of exposure to environmental stress.

OBJECTIVES

This seminar addresses the application of new tools and approaches for EV research, developed in part through the National Institutes of Health (NIH) Extracellular RNA Communication Program, and reflects presentations and discussions from a workshop held 27-28 September 2021 by the National Institute of Environmental Health Sciences (NIEHS) and the National Center for Advancing Translational Sciences (NCATS) on "Extracellular Vesicles, Exosomes, and Cell-Cell Signaling in Response to Environmental Stress." The panel of experts discussed current research on EVs and environmental exposures, highlighted recent advances in EV isolation and characterization, and considered research gaps and opportunities toward identifying and characterizing the roles for EVs in environmentally related diseases, as well as the current challenges and opportunities in this field.

DISCUSSION

The authors discuss the application of new experimental models, particularly organ-on-chip (OOC) systems and in vitro approaches and how these have the potential to extend findings in population-based studies of EVs in exposure-related diseases. Given the complex challenges of identifying cell-specific EVs related to environmental exposures, as well as the general heterogeneity and variability in EVs in blood and other accessible biological samples, there is a critical need for rigorous reporting of experimental methods and validation studies. The authors note that these efforts, combined with cross-disciplinary approaches, would ensure that future research efforts in environmental health studies on EV biomarkers are rigorous and reproducible. https://doi.org/10.1289/EHP12980.

Extracellular Vesicle-Encapsulated microRNAs as Novel Biomarkers of Lung Health

Rationale: Early detection of respiratory diseases is critical to facilitate delivery of disease-modifying interventions. Extracellular vesicle-enriched microRNAs (EV-miRNAs) may represent reliable markers of early lung injury. Objectives: Evaluate associations of plasma EV-miRNAs with lung function. Methods: The prospective NAS (Normative Aging Study) collected plasma EV-miRNA measurements from 1996-2015 and spirometry every 3-5 years through 2019. Associations of EV-miRNAs with baseline lung function were modeled using linear regression. To complement the individual miRNA approach, unsupervised machine learning was used to identify clusters of participants with distinct EV-miRNA profiles. Associations of EV-miRNA profiles with multivariate latent longitudinal lung function trajectories were modeled using log binomial regression. Biological functions of significant EV-miRNAs were explored using pathway analyses. Results were replicated in an independent sample of NAS participants and in the HEALS (Health Effects of Arsenic Longitudinal Study). Measurements and Main Results: In the main cohort of 656 participants, 51 plasma EV-miRNAs were associated with baseline lung function (false discovery rate-adjusted P value < 0.05), 28 of which were replicated in the independent NAS sample and/or in the HEALS cohort. A subset of participants with distinct EV-miRNA expression patterns had increased risk of declining lung function over time, which was replicated in the independent NAS sample. Significant EV-miRNAs were shown in pathway analyses to target biological pathways that regulate respiratory cellular immunity, the lung inflammatory response, and airway structural integrity. Conclusions: Plasma EV-miRNAs may represent a robust biomarker of subclinical lung injury and may facilitate early identification and treatment of patients at risk of developing overt lung disease.

Bronchial Asthma as a Cardiovascular Risk Factor: A Prospective Observational Study

Introduction: Asthma as a chronic inflammatory disorder has been suggested as a risk factor for endothelial dysfunction (ED), but studies on the association between asthma and cardiovascular disease (CVD) risk are limited. Background: We assessed associations of ED with the severity of asthma, eosinophilic inflammation, lung function, and asthma control. Methods: 52 young asthmatics (median age of 25.22 years) and 45 healthy individuals were included. Demographic, clinical, and laboratory findings were recorded. We evaluated microvascular responsiveness by recording the reactive hyperemia index (RHI) indicating post-occlusive peripheral endothelium-dependent changes in vascular tone using the Itamar Medical EndoPAT2000. VCAM-1, ADMA, high-sensitive CRP (hsCRP), and E-selectin were measured. Results: Asthmatics had considerably lower RHI values (p < 0.001) with a dynamic decreasing trend by asthma severity and higher hsCRP levels (p < 0.001). A substantial increase in hsCRP and E-selectin with asthma severity (p < 0.05) was also observed. We confirmed a higher body mass index (BMI) in asthmatics (p < 0.001), especially in women and in severe asthma. Conclusions: We demonstrated the progression of CVD in asthmatics and the association of the ongoing deterioration of ED with the inflammatory severity, suggesting that the increased risk of CVD in young asthmatics is dependent on disease severity. The underlying mechanisms of risk factors for CVD and disease control require further study.

Role of extracellular vesicles in lung diseases

ABSTRACT

Extracellular vesicles (EVs) are anuclear particles composed of lipid bilayers that contain nucleic acids, proteins, lipids, and organelles. EVs act as an important mediator of cell-to-cell communication by transmitting biological signals or components, including lipids, proteins, messenger RNAs, DNA, microRNAs, organelles, etc, to nearby or distant target cells to activate and regulate the function and phenotype of target cells. Under physiological conditions, EVs play an essential role in maintaining the homeostasis of the pulmonary milieu but they can also be involved in promoting the pathogenesis and progression of various respiratory diseases including chronic obstructive pulmonary disease, asthma, acute lung injury/acute respiratory distress syndrome, idiopathic pulmonary fibrosis (IPF), and pulmonary artery hypertension. In addition, in multiple preclinical studies, EVs derived from mesenchymal stem cells (EVs) have shown promising therapeutic effects on reducing and repairing lung injuries. Furthermore, in recent years, researchers have explored different methods for modifying EVs or enhancing EVs-mediated drug delivery to produce more targeted and beneficial effects. This article will review the characteristics and biogenesis of EVs and their role in lung homeostasis and various acute and chronic lung diseases and the potential therapeutic application of EVs in the field of clinical medicine.

The Emerging Role of Extracellular Vesicles Detected in Different Biological Fluids in COPD

The pathogenesis of chronic obstructive pulmonary disease (COPD) is characterized by complex cellular and molecular mechanisms, not fully elucidated so far. It involves inflammatory cells (monocytes/macrophages, neutrophils, lymphocytes), cytokines, chemokines and, probably, new players yet to be clearly identified and described. Chronic local and systemic inflammation, lung aging and cellular senescence are key pathological events in COPD development and progression over time. Extracellular vesicles (EVs), released by virtually all cells both as microvesicles and exosomes into different biological fluids, are involved in intercellular communication and, therefore, represent intriguing players in pathobiological mechanisms (including those characterizing aging and chronic diseases); moreover, the role of EVs as biomarkers in different diseases, including COPD, is rapidly gaining recognition. In this review, after recalling the essential steps of COPD pathogenesis, we summarize the current evidence on the roles of EVs collected in different biological mediums as biomarkers in COPD and as potential players in the specific mechanisms leading to disease development. We will also briefly review the data on EV as potential therapeutic targets and potential therapeutic agents.

Extracellular vesicles and chronic obstructive pulmonary disease (COPD): a systematic review

Background

Chronic Obstructive Pulmonary Disease (COPD) is a common inflammatory disease of the airways characterized by irreversible airflow limitation, ranking the third highest cause of death worldwide. Extracellular vesicles (EVs) are important intercellular communication mediators released by cells into their extracellular environment with the capacity to transfer biological signals. EVs involved in COPD hold great potential to understand disease pathogenesis and identify important biomarkers. This systematic review aims to examine all available research on EVs in the pathogenesis and diagnosis of COPD to identify existing knowledge and support further research within the field.

Methods

Publications were searched using PubMed and EMBASE with the search terms (Exosomes or extracellular vesicles or microvesicles or microparticles or ectosomes) AND (chronic obstructive pulmonary disease or COPD or emphysema or bronchitis).

Results

Initial search yielded 512 papers of which 142 were manually selected for review and 43 were eligible for analyses. The studies were divided into groups according to the role of EVs in pathogenesis, EV origin and cargo, their role in COPD exacerbations and their diagnostic utility. EVs were found to be involved in the mechanism of pathogenesis of COPD, derived from various cell types, as well as containing modified levels of miRNAs. EVs also varied according to the pathophysiological status of disease, therefore presenting a possible method for COPD diagnosis and progress monitoring.

Conclusion

The current findings show the limited but good quality research looking at the role of EVs in COPD, demonstrating the need for more studies to better define and provide further insight into the functional characteristics of EV in COPD pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01984-0.

Chronic obstructive pulmonary disease: moving from symptom relief to mortality reduction

Chronic obstructive pulmonary disease (COPD) has a 3-year mortality rate up to 37%, 2–6 times higher than the general population. We present evidence supporting pharmacological therapies to improve patient life expectancy, focusing on inhaled corticosteroids (ICSs) combined with long-acting bronchodilators (LABDs). A reduction in 3-year all-cause mortality (ACM) has been shown in patients with severe COPD treated with fluticasone propionate (an ICS) and salmeterol [long-acting beta-agonist (LABA)], compared with placebo. An observational study of elderly patients with severe COPD and multiple comorbidities suggested ICS+LABD reduce ACM compared with LABD monotherapy. Patients with symptomatic COPD at risk of exacerbations saw a mortality benefit with the ICS/long-acting muscarinic antagonist (LAMA)/LABA combinations fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) or budesonide/glycopyrrolate/formoterol (BUD/GLY/FOR) versus UMEC/VI or GLY/FOR (LAMA/LABA combinations) in the IMPACT and ETHOS trials, respectively. Reduced risk of mortality may be due to modulation of airway inflammation, thereby reducing activation of proinflammatory mediators in the peripheral circulation. Importantly, estimated annual risk reduction for ACM with ICS/LAMA/LABA combinations in patients with COPD is of the same order of magnitude as for statins (patients with coronary disease) and angiotensin-converting enzyme inhibitors (patients with vascular disease). Based on the current data, the pharmacological treatment of COPD appears not only able to improve symptoms and reduce the frequency of exacerbations but is also very promising in improving patient prognosis in the long term.

Extracellular vesicles: Their emerging roles in the pathogenesis of respiratory diseases

Alveoli are the basic structure of the lungs, consisting of various types of parenchymal and bone marrow-derived cells including alveolar macrophages. These various types of cells have several important functions; thus, communication between these cells plays an important role in homeostasis as well as in the pathophysiology of diseases in the lungs. For a better understanding of the pathophysiology of lung diseases, researchers have isolated each type of lung cell to investigate the changes in their gene expressions, including their humoral factor or adhesion molecules, to reveal the intercellular communication among these cells. In particular, investigations during the past decade have focused on extracellular vesicles, which are lipid bilayer delimited vesicles released from a cell that can move among various cells and transfer substances, including microRNAs, mRNAs and proteins, thus, functioning as intercellular messengers. Extracellular vesicles can be classified into three general groups: apoptotic bodies, exosomes, and microparticles. Extracellular vesicles, especially exosomes and microparticles, are attracting increasing attention from pulmonologists as tools for understanding pathogenesis and disease diagnosis. Here, we review studies, including our own, on exosomes and microparticles and their roles in both lung homeostasis and the pathogenesis of lung diseases such as idiopathic pulmonary fibrosis, chronic obstructive lung diseases, and acute respiratory distress syndrome. This review also addresses the roles of extracellular vesicles in COVID-19, the current global public health crisis.

Role of extracellular vesicles in chronic lung disease

To explore the role of extracellular vesicles (EVs) in chronic lung diseases.

EVs are emerging as mediators of intercellular communication and possible diagnostic markers of disease. EVs harbour cargo molecules including RNA, lipids and proteins that they transfer to recipient cells. EVs are intercellular communicators within the lung microenvironment. Due to their disease-specific cargoes, EVs have the promise to be all-in-one complex multimodal biomarkers. EVs also have potential as drug carriers in chronic lung disease.

Descriptive discussion of key studies of EVs as contributors to disease pathology, as biomarkers and as potential therapies with a focus on chronic obstructive pulmonary disorder (COPD), cystic fibrosis (CF), asthma, idiopathic pulmonary fibrosis and lung cancer.

We provide a broad overview of the roles of EV in chronic respiratory disease. Recent advances in profiling EVs have shown their potential as biomarker candidates. Further studies have provided insight into their disease pathology, particularly in inflammatory processes across a spectrum of lung diseases. EVs are on the horizon as new modes of drug delivery and as therapies themselves in cell-based therapeutics.

EVs are relatively untapped sources of information in the clinic that can help further detail the full translational nature of chronic lung disorders.

Extracellular vesicles: novel communicators in lung diseases

The lung is the organ with the highest vascular density in the human body. It is therefore perceivable that the endothelium of the lung contributes significantly to the circulation of extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies. In addition to the endothelium, EVs may arise from alveolar macrophages, fibroblasts and epithelial cells. Because EVs harbor cargo molecules, such as miRNA, mRNA, and proteins, these intercellular communicators provide important insight into the health and disease condition of donor cells and may serve as useful biomarkers of lung disease processes. This comprehensive review focuses on what is currently known about the role of EVs as markers and mediators of lung pathologies including COPD, pulmonary hypertension, asthma, lung cancer and ALI/ARDS. We also explore the role EVs can potentially serve as therapeutics for these lung diseases when released from healthy progenitor cells, such as mesenchymal stem cells.

Spermine on Endothelial Extracellular Vesicles Mediates Smoking-Induced Pulmonary Hypertension Partially Through Calcium-Sensing Receptor

Objective- This study aims to determine whether and how the enriched metabolites of endothelial extracellular vesicles (eEVs) are critical for cigarette smoke-induced direct injury of endothelial cells and the development of pulmonary hypertension, rarely explored in contrast to long-investigated mechanisms secondary to chronic hypoxemia. Approach and Results- Metabonomic screen of eEVs from cigarette-smoking human subjects reveals prominent elevation of spermine-a polyamine metabolite with potent agonist activity for the extracellular CaSR (calcium-sensing receptor). CaSR inhibition with the negative allosteric modulator Calhex231 or CaSR knockdown attenuates cigarette smoke-induced pulmonary hypertension in rats without emphysematous changes in lungs or chronic hypoxemia. Cigarette smoke exposure increases the generation of spermine-positive eEVs and their spermine content. Immunocytochemical staining and immunogold electron microscopy recognize the spermine enrichment not only within the cytosol but also on the outer surface of eEV membrane. The repression of spermine synthesis, the inhibitory analog of spermine, N¹-dansyl-spermine, Calhex231, or CaSR knockdown profoundly suppresses eEV exposure-mobilized cytosolic calcium signaling, pulmonary artery constriction, and smooth muscle cell proliferation. Confocal imaging of immunohistochemical staining demonstrates the migration of spermine-positive eEVs from endothelium into smooth muscle cells in pulmonary arteries of cigarette smoke-exposed rats. The repression of spermine synthesis or CaSR knockout results in attenuated development of pulmonary hypertension induced by an intravascular administration of eEVs. Conclusions- Cigarette smoke enhances eEV generation with spermine enrichment at their outer surface and cytosol, which activates CaSR and subsequently causes smooth muscle cell constriction and proliferation, therefore, directly leading to the development of pulmonary hypertension.

Endothelial Extracellular Vesicles in Pulmonary Function and Disease

The pulmonary vascular endothelium is involved in the pathogenesis of acute and chronic lung diseases. Endothelial cell (EC)-derived products such as extracellular vesicles (EVs) serve as EC messengers that mediate inflammatory as well as cytoprotective effects. EC-EVs are a broad term, which encompasses exosomes and microvesicles of endothelial origin. EVs are comprised of lipids, nucleic acids, and proteins that reflect not only the cellular origin but also the stimulus that triggered their biogenesis and secretion. This chapter presents an overview of the biology of EC-EVs and summarizes key findings regarding their characteristics, components, and functions. The role of EC-EVs is specifically delineated in pulmonary diseases characterized by endothelial dysfunction, including pulmonary hypertension, acute respiratory distress syndrome and associated conditions, chronic obstructive pulmonary disease, and obstructive sleep apnea.

Diagnostic value of platelet-derived microparticles in pulmonary thromboembolism: A population-based study

An early and accurate diagnosis of pulmonary thromboembolism (PTE) remains challenging. The present study aimed to evaluate the diagnostic value of platelet-derived microparticles in PTE based on a population study. A total of 102 patients with PTE, 102 healthy controls and 40 patients suspected with PTE were enrolled in this study. The platelet count, mean platelet volume and platelet distribution width were assessed using an automated hematology analyzer, P-selectin was assessed using an ELISA kit and PMPs were explored using flow cytometry using Megamix beads. Receiver operating characteristic curves were established to evaluate the diagnostic values of PMPs, D-dimer, PMPs combined with D-dimer, and multiple parameters (including PMPs, platelet distribution width, P-selectin and D-dimer in PTE). The PMP levels were significantly higher in the patients with PTE (609.10/µl) compared with those in the healthy controls (230.60/µl) and patients with suspicious PTE (166.70/µl; P<0.01). The accuracy (72.06%) of PMPs in the diagnosis of PTE was similar to those of D-dimer (P>0.05). The combination of D-dimer and PMPs significantly increased the sensitivity (86.27%) of D-dimer and the specificity of PMP for the diagnosis of PTE (P<0.01). The combination of PMPs, platelet distribution width, P-selectin and D-dimer exhibited high sensitivity (88.24%), specificity (91.18%) and accuracy (89.71%) in the diagnosis of PTE. These findings suggest that elevated PMP levels are an effective predictor of PTE. The combination of PMPs, platelet distribution width, P-selectin and D-dimer may be used in the diagnosis of PTE with high sensitivity and specificity.

Endothelial microvesicles in hypoxic hypoxia diseases

Hypoxic hypoxia, including abnormally low partial pressure of inhaled oxygen, external respiratory dysfunction-induced respiratory hypoxia and venous blood flow into the arterial blood, is characterized by decreased arterial oxygen partial pressure, resulting in tissue oxygen deficiency. The specific characteristics include reduced arterial oxygen partial pressure and oxygen content. Hypoxic hypoxia diseases (HHDs) have attracted increased attention due to their high morbidity and mortality and mounting evidence showing that hypoxia-induced oxidative stress, coagulation, inflammation and angiogenesis play extremely important roles in the physiological and pathological processes of HHDs-related vascular endothelial injury. Interestingly, endothelial microvesicles (EMVs), which can be induced by hypoxia, hypoxia-induced oxidative stress, coagulation and inflammation in HHDs, have emerged as key mediators of intercellular communication and cellular functions. EMVs shed from activated or apoptotic endothelial cells (ECs) reflect the degree of ECs damage, and elevated EMVs levels are present in several HHDs, including obstructive sleep apnoea syndrome and chronic obstructive pulmonary disease. Furthermore, EMVs have procoagulant, proinflammatory and angiogenic functions that affect the pathological processes of HHDs. This review summarizes the emerging roles of EMVs in the diagnosis, staging, treatment and clinical prognosis of HHDs.

Imbalance between endothelial damage and repair capacity in chronic obstructive pulmonary disease

Background

Circulating endothelial microparticles (EMPs) and progenitor cells (PCs) are biological markers of endothelial function and endogenous repair capacity. The study was aimed to investigate whether COPD patients have an imbalance between EMPs to PCs compared to controls and to evaluate the effect of cigarette smoke on these circulating markers.

Methods

Circulating EMPs and PCs were determined by flow cytometry in 27 nonsmokers, 20 smokers and 61 COPD patients with moderate to severe airflow obstruction. We compared total EMPs (CD31⁺CD42b^-), apoptotic if they co-expressed Annexin-V⁺ or activated if they co-expressed CD62E⁺, circulating PCs (CD34⁺CD133⁺CD45⁺) and the EMPs/PCs ratio between groups.

Results

COPD patients presented increased levels of total and apoptotic circulating EMPs, and an increased EMPs/PCs ratio, compared with nonsmokers. Women had less circulating PCs than men through all groups and those with COPD showed lower levels of PCs than both control groups. In smokers, circulating EMPs and PCs did not differ from nonsmokers, being the EMPs/PCs ratio in an intermediate position between COPD and nonsmokers.

Conclusions

We conclude that COPD patients present an imbalance between endothelial damage and repair capacity that might explain the frequent concurrence of cardiovascular disorders. Factors related to the disease itself and gender, rather than cigarette smoking, may account for this imbalance.

[Membranous microparticles and respiratory disease]

Microparticles (MP) are plasmic membrane fragments released from cells after physiological stimulation or stress conditions like inflammation or infection. Their production is correlated to the rate of cell apoptosis. All types of cells can produce MP but they are produced mainly by platelets, endothelial cells, and leukocytes. They carry many bio-active molecules on their surface, specific to the parental cell, giving them the ability to be biomarkers and bio-effectors. MP are present in circulating blood, tissues and many biological fluids. Circulating MP levels can change during the course of many diseases. They have been the subject of many studies in the fields of cardiovascular disease and oncology. In the lungs, they are present in circulating blood and in the airways. They seem to have a role in pulmonary homeostasis in physiological situations and also in the expression of several disease processes. In this review of the literature, we were interested in the quantitative and qualitative variations in MP and their impact in airway diseases like chronic obstructive pulmonary disease (COPD) and asthma, pulmonary fibrosis and pulmonary hypertension.

Inflammatory responses to acute elevations of carbon dioxide in mice

Health risks are described from elevated indoor air carbon dioxide (CO₂), which often ranges from 1,000 to 4,000 ppm, but the mechanisms are unknown. Here, we demonstrate that mice exposed for 2 h to 2,000 or 4,000 ppm CO₂ exhibit, respectively, 3.4 ± 0.9-fold (SE, n = 6) and 4.1 ± 0.7-fold (n = 10) elevations in circulating microparticles (MPs); neutrophil and platelet activation, and vascular leak in brain, muscle, and distal colon. Interleukin (IL)-1β content of MPs also increases after 2,000 ppm by 3.8 ± 0.6-fold (n = 6) and after 4,000 ppm CO₂ by 9.3 ± 1.1-fold (n = 10) greater than control. CO₂-induced vascular damage is abrogated by treating mice with an antibody to IL-1β or an IL-1β receptor inhibitor. Injecting naïve mice with CO₂-induced MPs expressing a protein found on mature neutrophils recapitulates vascular damage as seen with elevated CO₂, and destruction of MPs in CO₂-exposed mice abrogates vascular injuries without altering neutrophil or platelet activation. We conclude that environmentally relevant elevations of CO₂ trigger neutrophils to generate MPs containing high concentrations of IL-1β that cause diffuse inflammatory vascular injury.NEW & NOTEWORTHY Elevated levels of CO₂ are often found in indoor air and cause adverse health effects, but the mechanisms have not been identified. In a murine model, environmentally relevant levels of CO₂ were found to cause diffuse vascular damage because neutrophils are stimulated to produce microparticles that contain high concentrations of interleukin-1β.

Cell-derived microparticles and the lung

Cell-derived microparticles are small (0.1-1 μm) vesicles shed by most eukaryotic cells upon activation or during apoptosis. Microparticles carry on their surface, and enclose within their cytoplasm, molecules derived from the parental cell, including proteins, DNA, RNA, microRNA and phospholipids. Microparticles are now considered functional units that represent a disseminated storage pool of bioactive effectors and participate both in the maintenance of homeostasis and in the pathogenesis of diseases. The mechanisms involved in microparticle generation include intracellular calcium mobilisation, cytoskeleton rearrangement, kinase phosphorylation and activation of the nuclear factor-κB. The role of microparticles in blood coagulation and inflammation, including airway inflammation, is well established in in vitro and animal models. The role of microparticles in human pulmonary diseases, both as pathogenic determinants and biomarkers, is being actively investigated. Microparticles of endothelial origin, suggestive of apoptosis, have been demonstrated in the peripheral blood of patients with emphysema, lending support to the hypothesis that endothelial dysfunction and apoptosis are involved in the pathogenesis of the disease and represent a link with cardiovascular comorbidities. Microparticles also have potential roles in patients with asthma, diffuse parenchymal lung disease, thromboembolism, lung cancer and pulmonary arterial hypertension.

The role of the endothelium in asthma and chronic obstructive pulmonary disease (COPD)

COPD and asthma are important chronic inflammatory disorders with a high associated morbidity. Much research has concentrated on the role of inflammatory cells, such as the neutrophil, in these diseases, but relatively little focus has been given to the endothelial tissue, through which inflammatory cells must transmigrate to reach the lung parenchyma and cause damage. There is evidence that there is an abnormal amount of endothelial tissue in COPD and asthma and that this tissue and its’ progenitor cells behave in a dysfunctional manner. This article reviews the evidence of the involvement of pulmonary endothelium in COPD and asthma and potential treatment options for this.

Acute exacerbation of COPD: is it the "stroke of the lungs"?

Chronic obstructive pulmonary disease (COPD) is one of the top five major causes of morbidity and mortality worldwide. Despite worldwide health care efforts, costs, and medical research, COPD figures demonstrate a continuously increasing tendency in mortality. This is contrary to other top causes of death, such as neoplasm, accidents, and cardiovascular disease. A major factor affecting COPD-related mortality is the acute exacerbation of COPD (AECOPD). Exacerbations and comorbidities contribute to the overall severity in individual patients. Despite the underestimation by the physicians and the patients themselves, AECOPD is a really devastating event during the course of the disease, similar to acute myocardial infarction in patients suffering from coronary heart disease. In this review, we focus on the evidence that supports the claim that AECOPD is the “stroke of the lungs”. AECOPD can be viewed as: a Semicolon or disease’s full-stop period, Triggering a catastrophic cascade, usually a Relapsing and Overwhelming event, acting as a Killer, needing Emergent treatment.

MicroRNAs as Therapeutic Targets in Lung Disease: Prospects and Challenges

MicroRNAs (miRNAs) are small non-coding RNAs that regulate multiple target genes providing fine-tuned coordinated expression. Growing evidence suggests that miRNAs play important roles in lung development and the pathogenesis of lung disease and that they have great potential as novel therapeutic targets for the treatment of diseases such as lung cancer, asthma, pulmonary fibrosis, and chronic obstructive pulmonary disease (COPD). We have previously shown that miR-146a is a promising therapeutic target for controlling abnormal inflammatory response in COPD through a series of in vitro experiments in lung fibroblasts. However, further investigations in in vivo experimental models are needed to explore the role of miR-146a in the pathogenesis and therapy of COPD. Recently, miRNAs encapsulated in extracellular vesicles (EVs) have been recognized as modulators of intercellular communication. EVs, therefore, may also have therapeutic potential and show promise for use as biomarkers for various lung diseases. In addition to miRNAs, we briefly discuss a specific long non-coding RNA (lncRNA) that may contribute to the pathogenesis of COPD. The application of miRNA-based therapeutics faces several challenges related to mode of delivery, stability, and tissue specificity. However, recent advances in nanotechnology are expected to prove valuable for the development of miRNA-based therapeutics to treat lung disease.

Persistent endothelial dysfunction turns the frequent exacerbator COPD from respiratory disorder into a progressive pulmonary and systemic vascular disease

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death in developed countries of the world, while the main cause of mortality and morbidity in COPD patients are acute exacerbations and cardiovascular diseases. With regard to the frequency of exacerbations the phenotype "frequent exacerbators" has been defined, which, besides a more severe clinical course and a significantly higher total mortality, is also characterised by an elevated risk of cardiovascular mortality, as some indicators show us. It is notable that during the exacerbation of COPD, next to other changes, a significant aggravation of endothelial function occurs while the ED and COPD relationship seems very complex and is still in greater part unknown. Making the pathophysiological link between the frequency of exacerbations of COPD and ED could change our understanding of the character of this type of pulmonary disease. We hypothesize that frequent exacerbator COPD is a progressive and generalised vascular disease, not only an isolated respiratory disorder with ancillary systemic effects. Our opinion is that differences in COPD phenotype do not only determine the clinical picture but could also be of key importance in defining the progressivity of the disease. ED, which in these patients persists between frequent exacerbations, could be the main cause of the progression of pulmonary disease, and not only of the high cardiovascular risk of these patients. Such a persistent ED in FE COPD, with its pro-inflammatory, vasoconstrictory and prothrombotic mechanisms, could contemporaneously induce new exacerbations of COPD, the progression of pulmonary changes and the development of systemic atherosclerosis as a main extrapulmonary manifestation in these patients. Such a model defines endothelium as a common soil of progressive pulmonary and cardiovascular changes in FE COPD. It can fully explain all the elements of the clinical course and co-morbidity in FE COPD, for which we still do not have adequate explanation.