Airway endothelial dysfunction in asthma and chronic obstructive pulmonary disease: a challenge for future research

Comparative analysis of central aortic blood pressure, pulse wave velocity & arterial stiffness in patients with obstructive airway disease

BACKGROUND

As the pulmonary system and cardiovascular system are intimately linked, patients with chronic obstructive pulmonary disease (COPD) and asthma have high risk for developing cardiovascular diseases (CVDs) and altered central hemodynamic.

OBJECTIVE

We aim to assess the central aortic blood pressure (CABP) indices, pulse wave velocity (PWV) and other indicators of arterial stiffness in Indian patients with COPD and bronchial asthma.

METHODS

This is a single-center, cross-sectional study conducted in outpatients diagnosed with either chronic stable phase of COPD or bronchial asthma. CABP indices, vascular age, arterial stiffness and central hemodynamics were measured in patients.

RESULTS

Of 193 patients with obstructive airway disease who were enrolled, (n = 81 had COPD and n = 112 had partially-controlled bronchial asthma) the proportion of male patients was higher in both groups. The PWV, augmentation index (AI) and vascular age (VA) were significantly higher in patients with COPD compared to those with bronchial asthma (all, p < 0.05).

CONCLUSION

The study showed that PWV, AI and VA were higher in patients with stable COPD without any cardiac comorbidities compared to bronchial asthma.

Identification of toxicity-induced biomarkers in human non-immune airway cells exposed to respiratory sensitizers: A mechanistic approach

Occupational asthma covers a group of work-related diseases whose clinical manifestations include airway hyperresponsiveness and airflow limitation. Although the chemical respiratory allergy (CRA) induced by Low Molecular Weight (LMW) sensitizers is a major concern, especially in terms of the regulatory framework, to date there are no methods available for preclinically addressing this toxicological outcome, as its mechanistic background is not fully understood at molecular or cellular levels. This paper proposes a mechanistic study applying New Approach Methodologies (NAM) of the pro-inflammatory and functional effects triggered by LMW respiratory allergens in different respiratory tract cell lines, including bronchial epithelial (BEAS-2B), lung fibroblast (MRC-5), and endothelial cells (EA.hy926), and an analysis of the capacity of such chemicals to interact with the mucin protein, to address certain toxicodynamic aspects of such compounds. The results showed that some of the sensitizers evaluated interact with mucin, the main protein mucus component, but the toxicant-mucin complex formation does not seem to be a common feature of different chemical classes of allergens. At a cellular level, sensitizers promoted an increase in IL-8, IL-6, and IL-1β production in the evaluated cell types. It also impaired the MUC1 expression by bronchial cells and activated endothelial cells, thereby increasing the ICAM-I surface expression. Taken together, our results showed that these aforementioned cell types participate in the CRA Adverse Outcome Pathway and must be considered when developing preclinical testing strategies, particularly investigating danger signal production after exposure to LMW sensitizers in different tissue compartments.

Diabetic endothelial microangiopathy and pulmonary dysfunction

Type 2 diabetes mellitus (T2DM) is a widespread metabolic condition with a high global morbidity and mortality rate that affects the whole body. Their primary consequences are mostly caused by the macrovascular and microvascular bed degradation brought on by metabolic, hemodynamic, and inflammatory variables. However, research in recent years has expanded the target organ in T2DM to include the lung. Inflammatory lung diseases also impose a severe financial burden on global healthcare. T2DM has long been recognized as a significant comorbidity that influences the course of various respiratory disorders and their disease progress. The pathogenesis of the glycemic metabolic problem and endothelial microangiopathy of the respiratory disorders have garnered more attention lately, indicating that the two ailments have a shared history. This review aims to outline the connection between T2DM related endothelial cell dysfunction and concomitant respiratory diseases, including Coronavirus disease 2019 (COVID-19), asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF).

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.

Metabolic Syndrome and Its Correlates Among Female Chronic Obstructive Pulmonary Disease Patients at a Rural Tertiary Health Care Center in Northern India

Background: Chronic obstructive pulmonary disease (COPD) is a lung disease that is thought to result from chronic inflammation that may affect other organ systems. Similarly, metabolic syndrome includes central obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), hyperglycemia, and hypertension. The prevalence of metabolic syndrome and its associated factors among female COPD patients in northern India needs to be evaluated.

Aim and objectives: To find the prevalence of metabolic syndrome and its correlates among female chronic obstructive pulmonary disease patients at a rural tertiary health care center in northern India.

Materials and methods: A cross-sectional study was conducted between January 2019 and June 2020 at a rural tertiary health care center in northern India. The female patients who presented with symptoms of COPD and fulfilled the inclusion criteria were included and classified by Global Initiative for Chronic Obstructive Lung Disease (GOLD 2020) guideline while the clinical diagnosis of metabolic syndrome was made according to National Cholesterol Education Program: Adult Treatment Panel III (NCEP: ATP III) criteria.

Results: A total of 210 female COPD patients were included, the mean age of patients who had metabolic syndrome was 63.38±10.54 years. Metabolic syndrome was diagnosed in 60.48% of patients. There was a significant difference between female COPD patients with and without metabolic syndrome regarding body weight, BMI (body mass index), waist circumference, systolic blood pressure (SBP) and diastolic blood pressure (DBP), blood sugar, serum triglyceride, serum HDL-C. Whereas no significant difference was found between patients with and without metabolic syndrome group regarding smoking exposure, biomass fuel exposure, duration of biomass fuel exposure, mMRC (modified Medical Research Council) grading of breathlessness, GOLD grading of airflow limitation, route and duration of corticosteroid used. In our study, we also found a significant association between the severity of airflow limitation of COPD with the duration of biomass fuel exposure and BMI. Also, there was a significant association between biomass fuel exposure and the presence of cough in female COPD patients.

Conclusion: Metabolic syndrome is a prevalent entity in female COPD patients among the northern Indian population. Body weight, BMI, waist circumference, SBP, DBP, fasting blood sugar, serum triglyceride, and serum HDL-C have a significant impact on developing metabolic syndrome in female COPD patients. Duration of biomass fuel exposure and BMI also have a significant impact on the severity of airflow limitation in female COPD patients. So early detection and treatment of parameters of metabolic syndrome are important to reduce complications.

Human lung vascular endothelium may limit viral replication and recover in time upon the infection with rhinovirus HRV16

Vascular endothelium is a semi-permeable barrier that regulates the flow of nutrients, ions, cytokines, and immune cells between blood and tissues. Barrier properties of endothelium, its ability to regenerate, and the potential for secretion of inflammatory mediators play a crucial role in maintaining local tissue homeostasis. The lung vascular endothelial cells was shown to be infected by human rhinovirus and generate antiviral, inflammatory and cytopathic responses. The current study reveals that in the long-time manner the lung vascular endothelium may efficiently limit the HRV replication via the IFN-dependent 2'-5'-oligoadenylate synthetase 1 (OAS1) activation. This leads to the restoration of integrity accompanied by the up-regulation of adherens and tight junctions, increase of metabolic activity, and proliferation rate. Secondly, HRV16-infected cells show delayed and transient up-regulation of the expression of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiopoietin 1 and 2, and neurophilin-1 (NRP-1), as well as VEGF receptors. The lung vascular endothelium infected with HRV may limit the infection, recover in time, and regain barrier properties and metabolic functions, thus leading to the restoration of integrated barrier tissue.

Human rhinovirus 16 induces antiviral and inflammatory response in the human vascular endothelium

The effect of rhinovirus on airway epithelium is very well described. However, its influence on the vascular endothelium is unknown. The current study assesses the effect of rhinovirus HRV16 on the antiviral and inflammatory response in the human vascular endothelial cells (ECs). HRV16 increased IFN-β, RANTES, and IP-10 mRNA expression and protein release. HRV16 copy number in ECs reached maximal value 10 h after incubation. Increase in virus copies was accompanied by the enhancement of Toll- and RIG-I-like receptors: TLR3, RIG-I, and MDA5. Additionally, HRV16 increased OAS-1 and PKR mRNA expression, enzymes responsible for virus degradation and inhibition of replication. ICAM-1 blockade decreased HRV16 copy number in ECs and inhibited IFN-β, RANTES, IP-10, OAS1, PKR, TLR3, RIG-I, and MDA5 mRNA expression increase upon subsequent induction with HRV16. The vascular endothelium may be infected by human rhinovirus and generate antiviral and inflammatory innate response. Results of the study indicate the possible involvement of the vascular endothelium in the immunopathology of rhinoviral airway infections.

Regulatory T cells mediated immunomodulation during asthma: a therapeutic standpoint

Asthma is an inflammatory disease of the lung airway network, which is initiated and perpetuated by allergen-specific CD4⁺ T cells, IgE antibodies, and a massive release of Th2 cytokines. The most common clinical manifestations of asthma progression include airway inflammation, pathological airway tissue and microvascular remodeling, which leads to airway hyperresponsiveness (AHR), and reversible airway obstruction. In addition to inflammatory cells, a tiny population of Regulatory T cells (Tregs) control immune homeostasis, suppress allergic responses, and participate in the resolution of inflammation-associated tissue injuries. Preclinical and clinical studies have demonstrated a tremendous therapeutic potential of Tregs in allergic airway disease, which plays a crucial role in immunosuppression, and rejuvenation of inflamed airways. These findings supported to harness the immunotherapeutic potential of Tregs to suppress airway inflammation and airway microvascular reestablishment during the progression of the asthma disease. This review addresses the therapeutic impact of Tregs and how Treg mediated immunomodulation plays a vital role in subduing the development of airway inflammation, and associated airway remodeling during the onset of disease.

Assessment of biventricular function with speckle tracking echocardiography in newly-diagnosed adult-onset asthma

OBJECTIVE

There is limited number of studies on the effect of asthma disease on cardiac functions. The aim of this study was to investigate if there was any association between adult onset asthma and cardiac dysfunction.

METHODS

Total of 83 nonsmoking adult onset asthma patients aged between 18 and 65, and 83 control subjects with comparable age and sex distribution were included in the study.None of the subjects had any chronic cardiovascular or systemic diseases.Two-dimensional, M-mode and tissue Doppler examinations were performed. STE analysis was obtained using the QLAB software. Complete blood count and high-sensitive C-reactive protein (hsCRP) levels were measured.

RESULTS

There was no difference between two groups in terms of standard echocardiography and Doppler parameters. While tricuspid annular plane systolic excursion (TAPSE) was observed to be lower in asthmatics (24.9 ± 2.0 vs. 25.5 ± 2.1, p = 0.043), right ventricular myocardial performance index (RV MPI) was higher (0.36 ± 0.07 vs 0.32 ± 0.06, p˂0.001). There was no significant difference between the groups in terms of left ventricular STE parameters. Measurements of right ventricular global longitudinal strain (RVGLS) and right ventricular free wall strain (RVfree) were observed to be lower in the asthma group (-20.3 ± 2.9 vs -21.5 ± 2.9, p = 0.007; -24.0 ± 3.0 vs 25.1 ± 2.9, p = 0.009, respectively).

CONCLUSION

-We demonstrated that while adult onset mild-stage asthma patients have normal parameters in standard echocardiography, they have reduced right ventricular functions by STE.

Endothelial cells, neutrophils and platelets: getting to the bottom of an inflammatory triangle

Severe fibrotic and thrombotic events permeate the healthcare system, causing suffering for millions of patients with inflammatory disorders. As late-state consequences of chronic inflammation, fibrosis and thrombosis are the culmination of pathological interactions of activated endothelium, neutrophils and platelets after vessel injury. Coupling of these three cell types ensures a pro-coagulant, cytokine-rich environment that promotes the capture, activation and proliferation of circulating immune cells and recruitment of key pro-fibrotic cell types such as myofibroblasts. As the first responders to sterile inflammatory injury, it is important to understand how endothelial cells, neutrophils and platelets help create this environment. There has been a growing interest in this intersection over the past decade that has helped shape the development of therapeutics to target these processes. Here, we review recent insights into how neutrophils, platelets and endothelial cells guide the development of pathological vessel repair that can also result in underlying tissue fibrosis. We further discuss recent efforts that have been made to translate this knowledge into therapeutics and provide perspective as to how a compound or combination therapeutics may be most efficacious when tackling fibrosis and thrombosis that is brought upon by chronic inflammation.

Leukotriene D4 role in allergic asthma pathogenesis from cellular and therapeutic perspectives

Asthma is a chronic inflammatory and allergic disease that is mainly characterized by reversible airway obstruction and bronchial hyperresponsiveness. The incidence of asthma is increasing with more than 350 million people worldwide are affected. Up to now, there is no therapeutic option for asthma and most of the prescribed drugs aim to ameliorate the symptoms of the disease especially during the acute exacerbations after trigger exposure. Asthma is a heterogonous disease that involves interactions between inflammatory mediators and cellular components within the disease microenvironment including inflammatory and structural cells. Cysteinyl leukotrienes (cys-LTs) are inflammatory lipid mediators that have potent roles in asthma pathogenesis. CysLTs consisting of LTC₄, LTD₄, and LTE₄ are mainly secreted by leukocytes and act through three main G-protein coupled receptors (CysLT₁R, CysLT₂R, and CysLT₃R). LTD₄ is the most potent bronchoconstrictor which gives it the priority to be discussed in detail in this review. LTD₄ binds with high affinity to CysLT₁R and many studies showed that using CysLT₁R antagonists such as montelukast has a beneficial effect for asthmatics especially in corticosteroid refractory cases. Since asthma is a heterogeneous inflammatory disease of many cell types involved in the disease pathogenies and LTD₄ has a special role in inflammation and bronchoconstriction, this review highlights the role of LTD₄ on each cellular component in asthma and the benefits of using CysLT₁R antagonists in ameliorating LTD₄-induced effects.

Pulmonary Embolism in Acute Asthma Exacerbation: Clinical Characteristics, Prediction Model and Hospital Outcomes

PURPOSE

Little is known about the characteristics and impact of acute pulmonary embolism (PE) during episodes of asthma exacerbation. We aimed to characterize patients diagnosed with acute PE in the setting of asthma exacerbation, develop a prediction model to help identify future patients and assess the impact of acute PE on hospital outcomes.

METHODS

We included 758 patients who were treated for asthma exacerbation and underwent a computed tomographic pulmonary angiography (CTA) during the same encounter at a university-based hospital between June 2011 and October 2018. We compared clinical characteristics of patients with and without acute PE and developed a machine learning prediction model to classify the PE status based on the clinical variables. We used multivariable regression analysis to evaluate the impact of acute PE on hospital outcomes.

RESULTS

Twenty percent of the asthma exacerbation patients who underwent CTA had an acute PE. Factors associated with acute PE included previous history of PE, high CHA2DS2-VASc score, hyperlipidemia, history of deep vein thrombosis, malignancy, chronic systemic corticosteroids use, high body mass index and atrial fibrillation. Using these factors, we developed a random forest machine learning prediction model which had an 88% accuracy in classifying the acute PE status of the patients (area under the receiver operating characteristic curve = 0.899; 95% confidence interval: 0.885-0.913). Acute PE in asthma exacerbation was associated with longer hospital stay and intensive care unit stay.

CONCLUSION

It is important to consider acute PE, a potentially life-threatening event, in the setting of asthma exacerbation especially when other risk factors are present.

Fractional exhaled breath temperature in patients with asthma, chronic obstructive pulmonary disease, or systemic sclerosis compared to healthy controls

Exhaled breath temperature has been suggested to reflect airway inflammation, and it would be plausible to measure the peripheral airway temperature as a correlate to peripheral airway inflammation. This study aims to explore the relative peripheral airway temperature in patients with asthma, chronic obstructive pulmonary disease (COPD) or systemic sclerosis (SSc) compared to healthy controls, and relate to lung function and exhaled nitric oxide.

Sixty-five subjects (16 asthmatics, 18 COPD patients, 17 SSc patients and 14 healthy subjects) performed fractional exhaled breath temperature measurements using a novel device, fractional exhaled NO measurements, spirometry, impulse oscillometry, body plethysmography and CO-diffusion capacity test.

A significant overall difference among all the patient groups was seen in both the Tmax (= peak values of the entire exhalation) and T3max (= peak value of the last fraction of the exhaled volume). A significant difference in T3/T1 ratio (= the ratio of peripheral versus central air temperature) was found between asthmatic subjects and those with COPD or SSc. In addition, T1max (= temperature in the central), T3max (= peripheral airways) and the T3/T1ratio related to several volumetric measurements (both in absolute values and as percent predicted), such as vital capacity, total lung capacity, forced expiratory volume in 1 s, and diffusion capacity.

The temperature ratio of the peripheral versus central airways was lower in patients with COPD or SSc compared to asthmatics, who in turn presented similar levels as the controls. There was also a large overlap between the groups. Overall, the airway temperatures were related to absolute lung volumes, and specifically, the peripheral temperature was related to the gas diffusion capacity (% predicted), suggesting a link to the vascular component.

Endothelial Activation, Innate Immune Activation, and Inflammation Are Associated With Postbronchodilator Airflow Limitation and Obstruction Among Adolescents Living With HIV

BACKGROUND

Chronic inflammation, innate immune activation, T-cell imbalance and endothelial activation have been linked with lung diseases. We sought to determine whether markers of these pathophysiologic pathways were associated with spirometry and chest computed tomography (CT) abnormalities among adolescents living with HIV (ALWH).

SETTING

Coptic Hope Center for Infectious Diseases in Nairobi, Kenya.

METHODS

We performed a cross-sectional study of ALWH (10-19 years old). Participants underwent chest CT, spirometry, and venipuncture for serum biomarkers. We also collected demographic, anthropometric, T-cell subset, antiretroviral therapy, and exposure data. We compared characteristics and biomarkers by airflow obstruction [postbronchodilator FEV1/FVC z-score (zFEV1/FVC) < -1.64]. We used multivariable linear regression to determine associations of log10-transformed biomarkers and chest CT abnormalities with lower postbronchodilator zFEV1/FVC (airflow limitation). We performed exploratory principal components analysis on biomarkers, and determined associations of factors with postbronchodilator zFEV1/FVC and chest CT abnormalities.

RESULTS

Of 47 participants with acceptable quality spirometry, 21 (45%) were female, median age was 13 years and 96% had perinatally-acquired HIV. Median CD4 was 672 cells/µL. Overall, 28% had airflow obstruction and 78% had a chest CT abnormality; airflow obstruction was associated with mosaic attenuation (P = 0.001). Higher endothelial activation (sVCAM-1, sICAM-1), inflammation and innate immune activation (serum amyloid-A, sTREM-1, sCD163), and T-cell imbalance (lower CD4/CD8) markers were associated with airflow limitation. Factors comprising endothelial and innate immune activation were associated with airflow limitation.

CONCLUSIONS

Endothelial activation, innate immune activation, T-cell imbalance, and chronic inflammation are associated with airflow limitation and obstruction, providing insights into chronic lung disease pathophysiology among ALWH.

Pulmonary Embolism and Severe Asthma: Case Report and Literature Review

Pulmonary embolism is a life-threatening disease. Its development is generally thought to be due to causes collectively known as the Virchow's triad. Chronic inflammations are associated with the activation of coagulation and increased risks of venous thromboembolic events. Asthma is one of the chronic inflammatory diseases associated with procoagulants and antifibrinolytic activities in the airways. Coagulation is activated in patients with asthma with the following steps of pathophysiology: Increased tissue factor expression in various cell types, decreased activity of the anticoagulant protein C system and inhibition of fibrinolysis through over-production of plasminogen activator inhibitor type 1 (PAI-1). Asthma is therefore likely a risk factor for pulmonary embolism, especially in those patients with severe disease conditions together with frequent exacerbation. Here we present a case of severe asthma associated with coagulopathy and complicated by massive pulmonary embolism, presented with typical S1Q3T3 on electrocardiography (ECG) and massive thrombosis on computed tomography angiography, successfully treated with directed catheter thrombolytic therapy.

Molecular Characteristics and Treatment of Endothelial Dysfunction in Patients with COPD: A Review Article

Patients with chronic obstructive pulmonary disease (COPD) show systemic consequences, such as chronic systemic inflammation leading to changes in the airway, airway penetrability, and endothelial function. Endothelial dysfunction is characterized by a list of alterations of endothelium towards reduced vasodilation, proinflammatory state, detachment and apoptosis of endothelial cells, and development of atherosclerosis. COPD-induced endothelial dysfunction is associated with elevated cardiovascular risk. The increment of physical activities such as pulmonary rehabilitation (PR) training have a significant effect on COPD, thus, PR can be an integrative part of COPD treatment. In this narrative review the focus is on the function of endothelial inflammatory mediators [cytokines, chemokines, and cellular proteases] and pulmonary endothelial cells and endothelial dysfunction in COPD as well as the effects of dysfunction of the endothelium may play in COPD-related pulmonary hypertension. The relationship between smoking and endothelial dysfunction is also discussed. The connection between different pulmonary rehabilitation programs, arterial stiffness and pulse wave velocity (PWV) is presented. Endothelial dysfunction is a significant prognostic factor of COPD, which can be characterized by PWV. We discuss future considerations, like training programs, as an important part of the treatment that has a favorable impact on the endothelial function.

COPD beyond proximal bronchial obstruction: phenotyping and related tools at the bedside

Chronic obstructive pulmonary disease (COPD) is characterised by nonreversible proximal bronchial obstruction leading to major respiratory disability. However, patient phenotypes better capture the heterogeneously reported complaints and symptoms of COPD. Recent studies provided evidence that classical bronchial obstruction does not properly reflect respiratory disability, and symptoms now form the new paradigm for assessment of disease severity and guidance of therapeutic strategies. The aim of this review was to explore pathways addressing COPD pathogenesis beyond proximal bronchial obstruction and to highlight innovative and promising tools for phenotyping and bedside assessment. Distal small airways imaging allows quantitative characterisation of emphysema and functional air trapping. Micro-computed tomography and parametric response mapping suggest small airways disease precedes emphysema destruction. Small airways can be assessed functionally using nitrogen washout, probing ventilation at conductive or acinar levels, and forced oscillation technique. These tests may better correlate with respiratory symptoms and may well capture bronchodilation effects beyond proximal obstruction.Knowledge of inflammation-based processes has not provided well-identified targets so far, and eosinophils probably play a minor role. Adaptative immunity or specific small airways secretory protein may provide new therapeutic targets. Pulmonary vasculature is involved in emphysema through capillary loss, microvascular lesions or hypoxia-induced remodelling, thereby impacting respiratory disability.

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.

Reactive Oxygen Species in COPD-Related Vascular Remodeling

The pathogenesis of chronic obstructive pulmonary disease (COPD) is a multifaceted process involving the alteration of pulmonary vasculature. Such vascular remodeling can be associated with inflammation, shear stress, and hypoxia-conditions commonly seen in patients with lung diseases. Particularly, the overproduction of reactive oxygen species (ROS) in the diseased lungs contributes greatly to pulmonary vascular remodeling. ROS play an important role in vascular homeostasis, yet excessive ROS can alter pulmonary vasculature and impair lung function, as implicated in COPD at all stages. Increased inflammatory cell infiltration and endothelial dysfunction both correspond to the severity of COPD. As a byproduct of vascular remodeling, pulmonary hypertension negatively affects the long-term survival rate of COPD patients. While there is currently no cure for COPD, several treatment options have focused on alleviating COPD symptoms. Interventions such as long-term oxygen therapy, endothelium-targeted treatment, and pharmacological therapies show promising results in improving the life span of COPD patients and attenuating the progression of pulmonary hypertension. In this chapter, we aim to discuss the contributing factors of pulmonary vascular remodeling in COPD with an emphasis on the ROS, as well as potential redox treatments for COPD-related vascular remodeling.

Airway and Pulmonary β2-Adrenergic Vasodilatory Function in Current Smokers and Never Smokers

BACKGROUND

Cigarette smoking has been associated with diminished vasodilatory function in the airway circulation. It is possible that cigarette smoking similarly affects the pulmonary circulation before resting pulmonary circulatory abnormalities become manifested. The aim of this study was to compare the acute effect of inhaled albuterol on airway and pulmonary hemodynamic function as an index of β₂-adrenoceptor-mediated vasodilation in smokers and never smokers.

METHODS

In 30 adults, airway and pulmonary vascular function was assessed before and 15 min after albuterol inhalation (270 μg). From mean systemic arterial pressure, cardiac output, airway blood flow, and mean pulmonary arterial pressure, airway vascular resistance (AVR) and pulmonary vascular resistance (PVR) were derived.

RESULTS

Albuterol induced a substantial drop in mean (± SE) PVR (-67.2% ± 5%), with no difference between groups. In contrast, the albuterol-induced decrease in AVR was significantly greater in never smokers than in smokers (-28.6% ± 3% vs -3.1% ± 6%; P < .02).

CONCLUSIONS

These results are consistent with a dysfunction in a β₂-adrenergic signaling pathway mediating vasorelaxation in the airway circulation of current smokers. The vasodilatory deficit in the airway circulation but not in the pulmonary circulation could be related to local differences in the impact of cigarette smoke on the vascular endothelium.

Endocan and the respiratory system: a review

Endocan, formerly called endothelial cell-specific molecule 1, is an endothelial cell-associated proteoglycan that is preferentially expressed by renal and pulmonary endothelium. It is upregulated by proangiogenic molecules as well as by pro-inflammatory cytokines, and since it reflects endothelial activation and dysfunction, it is regarded as a novel tissue and blood-based relevant biomarker. As such, it is increasingly being researched and evaluated in a wide spectrum of healthy and disease pathophysiological processes. Here, we review the present scientific knowledge on endocan, with emphasis on the evidence that underlines its possible clinical value as a prognostic marker in several malignant, inflammatory and obstructive disorders of the respiratory system.

Oscillations of Skin Microvascular Blood Flow in Patients with Asthma

OBJECTIVE

This research is aimed at studying the features of skin blood flow oscillations in patients with severe persistent atopic BA during a period of fine control over symptoms.

METHODS

The study of microcirculation was carried out by LDF at rest and in response to a transient ischemia in 20 patients. The time-amplitude adaptive wavelet analysis of the blood flow oscillations was conducted to elucidate the peculiarities of microcirculatory regulation system functioning.

RESULTS

No significant changes were revealed for SBP and the oscillation amplitudes in the cardiac (0.6-2 Hz) and respiratory (0.145-0.6 Hz) intervals, both at rest and in response to transient ischemia, in patients compared to the control group. A consistent twofold decrease in the oscillation amplitudes was found in the neurogenic (0.021-0.052 Hz) interval at rest, as well as in the myogenic (0.052-0.145 Hz) and NO-dependent endothelial (0.0095-0.021 Hz) intervals both at rest and during the postocclusive reactive hyperemia in patients with lung obstruction (FEV1 < 80%) in comparison with a control group.

CONCLUSIONS

The amplitudes of skin blood flow oscillations in the myogenic, neurogenic and NO-dependent endothelial intervals in patients with obstruction are different from those in patients without obstruction.

Asthma-Chronic Obstructive Pulmonary Disease Overlap Syndrome Associated with Risk of Pulmonary Embolism

Purpose

We conducted a cohort study to clarify this relationship between asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) and pulmonary embolism (PE).

Methods

From the National Health Insurance Research Database of Taiwan, we identified patients who had a diagnosis of asthma and a diagnosis of COPD (defined as ACOS) and concurrent treatment between January 1999 and December 2009 (ACOS cohort: n = 14,150; non-ACOS cohort: n = 55,876). Cox proportional hazards regression analysis was performed to determine the adjusted hazard ratios (aHRs) for PE of the ACOS cohort compared with the non-ACOS cohort.

Results

Comparing the ACOS cohort with the non-ACOS cohort, the aHR of PE was 2.08 (95% confidence intervals [CIs]: 1.56–2.76). The risk of PE was higher in ACOS cohort than non-ACOS cohort, regardless of age, sex, comorbidity, inhaled corticosteroids (ICSs) and oral steroids (OSs) used. For ages ranging from 20 to 65 years, the aHR of PE was 2.53 (95% CI: 1.44–4.44) in the ACOS cohort. ACOS patients using ICSs (aHR: 1.97, 95% CI: 1.29–3.01) or OSs (aHR: 1.97, 95% CI: 1.46–2.65), the risk of PE was higher than in the non-ACOS cohort. The risk of PE increased with the number of outpatient visits and hospitalizations necessitated, ranging from 2.32 (95% CI: 1.54–3.52) in patients having 3–9 visits to 4.20 (95% CI: 2.74–6.44) for those having >9 visits.

Conclusions

ACOS is associated with increased risk of PE, particularly patients with a high frequency of AE—even in young adults or people without comorbidities.

Nanomedicines for Endothelial Disorders

The endothelium lines the internal surfaces of blood and lymphatic vessels and has a critical role in maintaining homeostasis. Endothelial dysfunction is involved in the pathology of many diseases and conditions, including disorders such as diabetes, cardiovascular diseases, and cancer. Given this common etiology in a range of diseases, medicines targeting an impaired endothelium can strengthen the arsenal of therapeutics. Nanomedicine - the application of nanotechnology to healthcare - presents novel opportunities and potential for the treatment of diseases associated with an impaired endothelium. This review discusses therapies currently available for the treatment of these disorders and highlights the application of nanomedicine for the therapy of these major disease complications.

Acute effect of an inhaled glucocorticosteroid on albuterol-induced bronchodilation in patients with moderately severe asthma

BACKGROUND

We have previously shown that in patients with asthma a single dose of an inhaled glucocorticosteroid (ICS) acutely potentiates inhaled albuterol-induced airway vascular smooth muscle relaxation through a nongenomic action. An effect on airway smooth muscle was not seen, presumably because the patients had normal lung function. The purpose of the present study was to conduct a similar study in patients with asthma with airflow obstruction to determine if an ICS could acutely also potentiate albuterol-induced airway smooth muscle relaxation in them.

METHODS

In 15 adult patients with asthma (mean ± SE baseline FEV1, 62% ± 3%), the response to inhaled albuterol (180 μg) was assessed by determining the change in FEV1 (ΔFEV1) for airway smooth muscle and in airway blood flow (ΔQaw) for airway vascular smooth muscle measured 15 min after drug inhalation. Using a double-blind design, the patients inhaled a single dose of the ICS mometasone (400 μg) or placebo simultaneously with or 30 min before albuterol inhalation.

RESULTS

After simultaneous drug administration, mean ΔFEV1 was 0.20 ± 0.05 L (10%) after placebo and 0.32 ± 0.04 L (19%) after mometasone (P < .05); mean ΔQaw was -2% after placebo and 30% after mometasone (P < .005). When mometasone or placebo was administered 30 min before albuterol, there was a lesser and insignificant difference in ΔFEV1 between the two treatments, whereas the difference in ΔQaw remained significant.

CONCLUSIONS

This pilot study showed that in adult patients with asthma with airflow obstruction, a single standard dose of an ICS can acutely increase the FEV1 response to a standard dose of inhaled albuterol administered simultaneously. The associated potentiation of albuterol-induced vasodilation in the airway was of greater magnitude and retained when the ICS was administered 30 min before albuterol. The clinical significance of this observation will have to be established by a study involving a larger patient cohort.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01210170; URL: www.clinicaltrials.gov.

Effect of airway acidosis and alkalosis on airway vascular smooth muscle responsiveness to albuterol

Background

In vitro and animal experiments have shown that the transport and signaling of β₂-adrenergic agonists are pH-sensitive. Inhaled albuterol, a hydrophilic β₂-adrenergic agonist, is widely used for the treatment of obstructive airway diseases. Acute exacerbations of obstructive airway diseases can be associated with changes in ventilation leading to either respiratory acidosis or alkalosis thereby affecting albuterol responsiveness in the airway. The purpose of this study was to determine if airway pH has an effect on albuterol-induced vasodilation in the airway.

Methods

Ten healthy volunteers performed the following respiratory maneuvers: quiet breathing, hypocapnic hyperventilation, hypercapnic hyperventilation, and eucapnic hyperventilation (to dissociate the effect of pH from the effect of ventilation). During these breathing maneuvers, exhaled breath condensate (EBC) pH and airway blood flow response to inhaled albuterol (ΔQ̇_aw) were assessed.

Results

Mean ± SE EBC pH (units) and ΔQ̇_aw (μl.min^-1.mL^-1) were 6.4 ± 0.1 and 16.8 ± 1.9 during quiet breathing, 6.3 ± 0.1 and 14.5 ± 2.4 during eucapnic hyperventilation, 6.6 ± 0.2 and -0.2 ± 1.8 during hypocapnic hyperventilation (p = 0.02 and <0.01 vs. quiet breathing), and 5.9 ± 0.1 and 2.0 ± 1.5 during hypercapnic hyperventilation (p = 0.02 and <0.02 vs quiet breathing).

Conclusions

Albuterol responsiveness in the airway as assessed by ΔQ̇_aw is pH sensitive. The breathing maneuver associated with decreased and increased EBC pH both resulted in a decreased responsiveness independent of the level of ventilation. These findings suggest an attenuated response to hydrophilic β₂-adrenergic agonists during airway disease exacerbations associated with changes in pH.

Trial registration

Registered at clinicaltrials.gov: NCT01216748.

Chronic obstructive pulmonary disease and the metabolic syndrome: Consequences of a dual threat

The metabolic syndrome is found to be more frequent in chronic obstructive pulmonary disease (COPD). The presence of inflammatory markers in circulation, sputum, and broncho-alveolar fluid suggest systemic inflammation is one of the potential mechanisms responsible for both COPD and metabolic syndrome. Physical inactivity, skeletal muscle dysfunction, hypogonadism, and steroid use are also important causes of the metabolic syndrome in COPD. Obesity and insulin resistance is found to be more common in mild to moderate stages (I and II) of COPD. Patients with COPD and the metabolic syndrome have increase risk of morbidity and mortality due to cardiovascular disease. This review describes in details the various components of metabolic syndrome and its impact on long outcomes in COPD patients.

Inhaled budesonide protects against chronic asthma-induced neuroinflammation in mouse brain

Chronic asthma is one of the most common respiratory diseases, characterized by airway inflammation. However, little is known whether asthma-induced airway inflammation might influence the brain. We found that chronic asthma not only resulted in peripheral inflammation, but also induced neuroinflammation which was characterized by microglial activations and increased levels of TNFα and IL-1β in the hippocampus and prefrontal cortex. Simultaneously, we found that there was significant neuronal loss in the asthmatic mouse brain. Inhaled budesonide, the classic therapeutic drug for chronic asthma, could inhibit asthma-induced microglial activation, down-regulate TNFα and IL-1β but up-regulate TGFβ and IL-10 of mouse brain, and thereby attenuate neuronal loss. Further study showed that chronic asthma increased the expressions of TLR4 and p65/NFκB in the brain, which could be reversed by budesonide treatment. Therefore, the present study reveals that inhaled budesonide protects against asthma-induced neuroinflammation in mouse brain, which might be contributed to attenuate neuronal loss.

The role of dendritic cells in the pathogenesis of cigarette smoke-induced emphysema in mice

Chronic Obstructive Pulmonary Disease (COPD) is an important lung and airway disease which affects the lives of around 200 million people worldwide. The pathological hallmark of COPD is emphysema and bronchiolitis and is based on the inflammatory response of the innate and adaptive immune system to the inhalation of toxic particles and gases. The inflamed airways of COPD patients contain several inflammatory cells including neutrophils, macrophages, T lymphocytes, and dendritic cells (DC). The potential role of DCs as mediators of inflammation in the airways of smokers and COPD patients is poorly understood. The current study investigated the role of DC subsets in an animal model of cigarette smoke-induced lung emphysema through the expansion or depletion of DC subsets. Expansion of both myeloid DC (mDC) and plasmacytoid DC (pDC) by Flt3L treatment induced a decline in macrophage numbers and increased the levels of fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) in the bronchoalveolar lavage (BAL) fluid of smoke-exposed animals. The increase in the mean linear intercept (Lm) following Flt3L treatment was decreased by pDC depletion. In conclusion, pharmacological modulation of DC subsets may have an effect on the development of airway responses and emphysema as indicated by the decline in macrophage numbers and the increase in FGF and VEGF levels in the bronchoalveolar lavage fluid. Moreover, the depletion of pDCs decreased the Lm which might suggest a role for pDC in the pathogenesis of lung emphysema.

Serum methylarginines and spirometry-measured lung function in older adults

Rationale

Methylarginines are endogenous nitric oxide synthase inhibitors that have been implicated in animal models of lung disease but have not previously been examined for their association with spirometric measures of lung function in humans.

Objectives

This study measured serum concentrations of asymmetric and symmetric dimethylarginine in a representative sample of older community-dwelling adults and determined their association with spirometric lung function measures.

Methods

Data on clinical, lifestyle, and demographic characteristics, methylated arginines, and L-arginine (measured using LC-MS/MS) were collected from a population-based sample of older Australian adults from the Hunter Community Study. The five key lung function measures included as outcomes were Forced Expiratory Volume in 1 second, Forced Vital Capacity, Forced Expiratory Volume in 1 second to Forced Vital Capacity ratio, Percent Predicted Forced Expiratory Volume in 1 second, and Percent Predicted Forced Vital Capacity.

Measurements and Main Results

In adjusted analyses there were statistically significant independent associations between a) higher asymmetric dimethylarginine, lower Forced Expiratory Volume in 1 second and lower Forced Vital Capacity; and b) lower L-arginine/asymmetric dimethylarginine ratio, lower Forced Expiratory Volume in 1 second, lower Percent Predicted Forced Expiratory Volume in 1 second and lower Percent Predicted Forced Vital Capacity. By contrast, no significant associations were observed between symmetric dimethylarginine and lung function.

Conclusions

After adjusting for clinical, demographic, biochemical, and pharmacological confounders, higher serum asymmetric dimethylarginine was independently associated with a reduction in key measures of lung function. Further research is needed to determine if methylarginines predict the decline in lung function.

The epidemiology of vascular dysfunction relating to chronic obstructive pulmonary disease and emphysema

Cor pulmonale has long been described in very severe chronic obstructive pulmonary disease (COPD) and emphysema. Cross-sectional results from population-based studies show that left ventricular filling and a variety of vascular measures in the systemic circulation are abnormal in preclinical COPD and emphysema and that a predominant vascular change in COPD and emphysema is endothelial and microvascular dysfunction. These findings suggest that pulmonary vascular changes may occur early in COPD and emphysema and might contribute to pathogenesis. However, longitudinal epidemiologic studies with direct measures of the pulmonary vasculature are lacking; therefore, inferences are limited at present. New imaging-based approaches to the assessment of the pulmonary vasculature are applicable to epidemiologic studies and may help in defining the relationship of pulmonary vascular damage to progression of COPD and emphysema. These measures may also provide imaging-based surrogate markers, and novel therapeutics targeted to the pulmonary vasculature might reduce symptoms and improve function in these common diseases.

Role of Inhaled Steroids in Vascular Airway Remodelling in Asthma and COPD

In chronic obstructive airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), changes in bronchial microvasculature are present in response to inflammatory stimuli. Vascular changes may significantly contribute to airway wall remodelling. Angiogenesis and vascular leakage are prevalent in asthma, while vasodilation and vascular leakage dominate in COPD. An endothelial dysfunction may be present both in asthma and in COPD. Vascular changes may occur simultaneously with the thickening of the airway wall and the narrowing of the bronchial lumen. Consequently, pharmacological control of bronchial vascular remodelling may be crucial for symptom control in asthma and COPD. In asthmatic airways, inhaled steroids can downregulate vascular remodelling by acting on proangiogenic factors. Additionally, studies on combination therapy with long-acting β2-agonists and inhaled steroids have provided evidence of a possible synergistic action on components of vascular remodelling in asthma. In COPD, there is less experimental evidence on the effect of inhaled steroids on airway microvascular changes. Importantly, vascular endothelial growth factor (VEGF), the most specific growth factor for vascular endothelium, is crucially involved in the pathophysiology of airway vascular remodelling, both in asthma and COPD. The inhibition of VEGF and its receptor may be useful in the treatment of the vascular changes in the airway wall.

Update in chronic obstructive pulmonary disease: role of antioxidant and metabolizing gene polymorphisms

Chronic obstructive pulmonary disease (COPD) is characterized by systemic and local chronic inflammation and oxidative stress. The sources of the increased oxidative stress in COPD patients derive from the increased burden of inhaled oxidants such as cigarette smoke and other forms of particulate or gaseous air pollution and from the increase in reactive oxygen species (ROS) generated by several inflammatory, immune, and structural airways cells. There is increasing evidence that genetic factors may also contribute to the pathogenesis if COPD, particularly antioxidant genes, which may confer a susceptibility to environmental insults such as cigarette smoke and thereafter development of COPD. Consequently, heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), microsomal epoxide hydrolase (EPHX1), and cytochrome P450 (CYP) genetic polymorphisms may have an important role in COPD pathogenesis. In this review the authors summarized the most recent findings dealing with these antioxidant genes contributing to the free radical neutralization and xenobiotic enzymes playing a role in different phases of cell detoxification reactions related to the redox status imbalance in COPD, with an emphasis on their possible roles in disease progression.

COPD/emphysema: The vascular story

In this perspective, we review published data which support the concept that many or most chronic and progressive lung diseases also involve the lung vessels and that microvascular abnormalities and endothelial cell death contribute to the pathobiology of emphysema. Lung vessel maintenance depends on Vascular Endothelial Growth Factor signaling and both are compromised in the emphysematous lung tissue. Although hypoxic pulmonary vasoconstriction has been considered as an important factor contributing to the vascular remodeling in chronic obstructive pulmonary disease (COPD) (COPD/emphysema, it is now clear that inhaled cigarette smoke can damage the lung vessels independent of the lung vascular tone. We propose that a "sick lung circulation" rather than the right heart afterload may better explain the cardiac abnormalities in COPD patients which are usually summarized with the term "cor pulmonale." The mechanisms and causes of pulmonary hypertension are likely complex and include vessel loss, in situ thrombosis, and endothelial cell dysfunction. Assessment of the functional importance of pulmonary hypertension in COPD requires hemodynamic measurements during exercise.

Nox enzymes in allergic airway inflammation

Chronic airway diseases such as asthma are linked to oxidative environmental factors and are associated with increased production of reactive oxygen species (ROS). Therefore, it is commonly assumed that oxidative stress is an important contributing factor to asthma disease pathogenesis and that antioxidant strategies may be useful in the treatment of asthma. A primary source of ROS production in biological systems is NADPH oxidase (NOX), originally associated primarily with inflammatory cells but currently widely appreciated as an important enzyme system in many cell types, with a wide array of functional properties ranging from antimicrobial host defense to immune regulation and cell proliferation, differentiation and apoptosis. Given the complex nature of asthma disease pathology, involving many lung cell types that all express NOX homologs, it is not surprising that the contributions of NOX-derived ROS to various aspects of asthma development and progression are highly diverse and multifactorial. It is the purpose of the present review to summarize the current knowledge with respect to the functional aspects of NOX enzymes in various pulmonary cell types, and to discuss their potential importance in asthma pathogenesis. This article is part of a Special Issue entitled: Biochemistry of Asthma.