Background and Purpose: Cardiovascular disease (CVD) affects up to half of the patients with chronic obstructive pulmonary disease (COPD), which exerts deleterious impact on health outcomes and survivability. Vascular endothelial dysfunction marks the onset of cardiovascular disease. The present study examined the effect of a potent NADPH Oxidase (NOX) inhibitor and free-radical scavenger, apocynin, on COPD-related CVD. Experimental Approach: Male BALB/c mice were exposed to either room air (Sham) or cigarette smoke (CS) generated from 9 cigarettes per day, 5 days a week for up to 24 weeks with or without apocynin treatment (5 mg·kg-1·day-1, intraperitoneal injection). Key Results: Eight-weeks of apocynin treatment reduced airway neutrophil infiltration (by 42%) and completely preserved endothelial function and endothelial nitric oxide synthase (eNOS) activity against the oxidative insults of CS exposure. These preservative effects were maintained up until the 24-week time point. 24-week of apocynin treatment exhibited marked benefits on airway inflammation (reduced infiltration of macrophage, neutrophil and lymphocyte) and lung function decline (hyperinflation), and prevented airway collagen deposition by CS exposure. Conclusion and Implications: Limiting NOX activity may slow COPD progression and lower CVD risk, particularly when signs of oxidative stress become evident.

Background and Purpose: People with COPD are susceptible to respiratory infections which exacerbate pulmonary and/or cardiovascular complications, increasing their likelihood of death. The mechanisms driving these complications remain unknown but increased oxidative stress has been implicated. Here we investigated whether influenza A virus (IAV) infection, following chronic cigarette smoke (CS) exposure, worsens vascular function and if so, whether the antioxidant ebselen alleviates this vascular dysfunction. Experimental Approach: Male BALB/c mice were exposed to either room air or CS for 8 weeks followed by inoculation with IAV (Mem71, 1 x 104.5 pfu)). Mice were treated with ebselen (10 mg/kg) or vehicle (5% w/v CM-cellulose in water) daily. Mice were culled 3- and 10-days post-infection, and their lungs lavaged to assess inflammation. The thoracic aorta was excised to investigate endothelial and smooth muscle dilator responses, expression of key vasodilatory and oxidative stress modulators and infiltrating immune cells. Key Results: CS increased lung inflammation and caused significant vascular endothelial dysfunction, which was worsened by IAV infection. CS-driven increases in vascular oxidative stress and suppression of eNOS were not affected by IAV infection. CS and IAV infection significantly enhanced T-cell recruitment into the aortic wall. Ebselen abolished the exaggerated lung inflammation, vascular dysfunction and increased aortic T-cell infiltration in CS and IAV-infected mice. Conclusion and Implications: Ebselen abolished vascular dysfunction in IAV-induced exacerbations of cigarette smoke-induced lung inflammation indicating it may have potential for the treatment of cardiovascular comorbidities seen in acute exacerbations of COPD.

Background and Purpose: Cigarette smoking (CS) is the major risk factor for developing COPD and related skeletal muscle dysfunction. It has been postulated that CS exposure may directly causes muscle dysfunction via the induction of oxidative stress. The present study examined the effect of a potent Nox inhibitor and ROS scavenger, apocynin on CS-induced muscle dysfunction. Experimental Approach: Male BALB/c mice were exposed to either room air (sham) or CS generated from 9 cigarettes per day, 5 days a week for 8 weeks with or without apocynin treatment (5 mg·kg-1 w/v, intraperitoneal injection). C2C12 myotubes exposed to either hydrogen peroxide (H2O2) or water-soluble cigarette smoke extract (CSE) with or without apocynin (500 nM), was set up as an experimental model in vitro. Key Results: Eight weeks of CS exposure caused significant lung inflammation and muscle dysfunction in mice; evidenced by a 10% loss in muscle mass and 54% loss in contractile function of tibialis anterior, attributable to altered myogenic homeostasis and protein oxidation. These effects were prevented by apocynin administration. In C2C12 myotubes, direct exposure to H2O2 or CSE caused myofiber wasting, which was associated with altered myogenic homeostasis marked by ~50% loss in muscle-derived insulin-like growth factor (IGF)-1 and 1.5-fold increase in myostatin expression. Apocynin treatment completely attenuated CSE-induced Nox2 expression, preserving muscle-derived IGF-1 expression and downstream mammalian target of rapamycin (mTOR) signaling pathway, thereby preventing myofiber wasting. Conclusion and Implications: Targeted pharmacological inhibition of Nox-derived ROS may alleviate the lung and systemic manifestations in smokers with COPD.

Background and Purpose: It is well established that both smokers and patients with COPD are at a significantly heightened risk of cardiovascular disease (CVD), although the mechanisms underpinning the onset and progression of comorbid CVD are largely unknown. Here, we explored whether cigarette smoke (CS) exposure impairs vascular function in mice and given the well-known pathological role for oxidative stress in COPD, whether the antioxidant compound ebselen prevents CS-induced vascular dysfunction in mice. Experimental Approach: Male BALB/c mice were exposed to either room air (sham) or CS generated from 9 cigarettes per day, 5 days a week for 8 weeks. Mice were treated with ebselen (10mg/kg, oral gavage once daily) or vehicle (5% w/v CM cellulose in water) 1 h prior to the first CS exposure of the day. Upon sacrifice, bronchoalveolar lavage fluid (BALF) was collected to assess pulmonary inflammation and the thoracic aorta was excised to investigate vascular endothelial and smooth muscle dilator responses ex-vivo. Key Results: CS exposure caused a significant increase in lung inflammation which was reduced by ebselen. CS also caused significant endothelial dysfunction in the thoracic aorta which was attributed to a downregulation of eNOS expression and increased vascular oxidative stress. Ebselen abolished the aortic endothelial dysfunction seen in CS-exposed mice by reducing the oxidative burden and preserving eNOS expression. Conclusion and Implications: Targeting CS-induced oxidative stress with ebselen may provide a novel means for treating the life-threatening pulmonary and cardiovascular manifestations associated with cigarette smoking and COPD.