Rosa C. Gualano

Cigarette smoke worsens lung inflammation and impairs resolution of influenza infection in mice

BackgroundCigarette smoke has both pro-inflammatory and immunosuppressive effects. Both active and passive cigarette smoke exposure are linked to an increased incidence and severity of respiratory virus infections, but underlying mechanisms are not well defined. We hypothesized, based on prior gene expression profiling studies, that upregulation of pro-inflammatory mediators by short term smoke exposure would be protective against a subsequent influenza infection.MethodsBALB/c mice were subjected to whole body smoke exposure with 9 cigarettes/day for 4 days. Mice were then infected with influenza A (H3N1, Mem71 strain), and analyzed 3 and 10 days later (d3, d10). These time points are the peak and resolution (respectively) of influenza infection.ResultsInflammatory cell influx into the bronchoalveolar lavage (BALF), inflammatory mediators, proteases, histopathology, viral titres and T lymphocyte profiles were analyzed. Compared to smoke or influenza alone, mice exposed to smoke and then influenza had more macrophages, neutrophils and total lymphocytes in BALF at d3, more macrophages in BALF at d10, lower net gelatinase activity and increased activity of tissue inhibitor of metalloprotease-1 in BALF at d3, altered profiles of key cytokines and CD4+ and CD8+ T lymphocytes, worse lung pathology and more virus-specific, activated CD8+ T lymphocytes in BALF. Mice smoke exposed before influenza infection had close to 10-fold higher lung virus titres at d3 than influenza alone mice, although all mice had cleared virus by d10, regardless of smoke exposure. Smoke exposure caused temporary weight loss and when smoking ceased after viral infection, smoke and influenza mice regained significantly less weight than smoke alone mice.ConclusionSmoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza. This animal model may be useful in studying how smoke worsens respiratory viral infections.

Epidermal Growth Factor Receptor Signaling to Erk1/2 and STATs Control the Intensity of the Epithelial Inflammatory Responses to Rhinovirus Infection

Rhinovirus infection is the most common cause of acute exacerbations of inflammatory lung diseases, such as asthma and chronic obstructive pulmonary disease, where it provokes steroid refractory and abnormally intense neutrophilic inflammation that can be life threatening. Epidermal growth factor receptor (EGFR) expression correlates with disease severity and neutrophil infiltration in these conditions. However, the role of EGFR signaling in rhinovirus infection is unknown. We measured the key determinants of neutrophilic inflammation interleukin (IL)-8 and ICAM-1 in rhinovirus (RV16 serotype)-infected bronchial epithelial cells, BEAS-2B. RV16 infection stimulated IL-8 and ICAM-1 expression, which was further elevated (2-fold) by transient up-regulation of EGFR levels. Detection of viral RNA by quantitative real time PCR confirmed that enhanced expression was not associated with increased viral replication. EGFR ligands (epiregulin, amphiregulin, and heparin-binding epidermal growth factor) were induced by RV16 infection, and inhibition of metalloproteases responsible for ligand shedding partially suppressed this response. The EGFR inhibitor AG1478, completely blocked IL-8 and ICAM-1 expression to basal levels, as did the specific Erk1/2 inhibitor U0126. The p38 mitogen-activated protein kinase inhibitor SB203580 blocked IL-8 secretion but not ICAM-1 expression, whereas the PI3K inhibitor wortmannin was ineffective in both responses. Kinase inactive K721R EGFR, which is selectively deficient in STAT signaling, reversed RV16 responses associated with EGFR overexpression. In conclusion, RV16 infection rapidly promotes induction of EGFR ligands and utilizes EGFR signaling to increase IL-8 and ICAM-1 levels. These results suggest that targeting EGFR may provide a selective therapy that dampens neutrophil-driven inflammation without compromising essential antiviral pathways mediated by pathogen recognition receptors such as TLR3.

Sexual dimorphism in lung function responses to acute influenza A infection

Please cite this paper as: Larcombe et al. (2011) Sexual dimorphism in lung function responses to acute influenza A infection. Influenza and Other Respiratory Viruses 5(5), 334–342.

Hyperresponsiveness to inhaled but not intravenous methacholine during acute respiratory syncytial virus infection in mice

BackgroundTo characterise the acute physiological and inflammatory changes induced by low-dose RSV infection in mice.MethodsBALB/c mice were infected as adults (8 wk) or weanlings (3 wk) with 1 × 105 pfu of RSV A2 or vehicle (intranasal, 30 μl). Inflammation, cytokines and inflammatory markers in bronchoalveolar lavage fluid (BALF) and airway and tissue responses to inhaled methacholine (MCh; 0.001 – 30 mg/ml) were measured 5, 7, 10 and 21 days post infection. Responsiveness to iv MCh (6 – 96 μg/min/kg) in vivo and to electrical field stimulation (EFS) and MCh in vitro were measured at 7 d. Epithelial permeability was measured by Evans Blue dye leakage into BALF at 7 d. Respiratory mechanics were measured using low frequency forced oscillation in tracheostomised and ventilated (450 bpm, flexiVent) mice. Low frequency impedance spectra were calculated (0.5 – 20 Hz) and a model, consisting of an airway compartment [airway resistance (Raw) and inertance (Iaw)] and a constant-phase tissue compartment [coefficients of tissue damping (G) and elastance (H)] was fitted to the data.ResultsInflammation in adult mouse BALF peaked at 7 d (RSV 15.6 (4.7 SE) vs. control 3.7 (0.7) × 104 cells/ml; p < 0.001), resolving by 21 d, with no increase in weanlings at any timepoint. RSV-infected mice were hyperresponsive to aerosolised MCh at 5 and 7 d (PC200 Raw adults: RSV 0.02 (0.005) vs. control 1.1 (0.41) mg/ml; p = 0.003) (PC200 Raw weanlings: RSV 0.19 (0.12) vs. control 10.2 (6.0) mg/ml MCh; p = 0.001). Increased responsiveness to aerosolised MCh was matched by elevated levels of cysLT at 5 d and elevated VEGF and PGE2 at 7 d in BALF from both adult and weanling mice. Responsiveness was not increased in response to iv MCh in vivo or EFS or MCh challenge in vitro. Increased epithelial permeability was not detected at 7 d.ConclusionInfection with 1 × 105 pfu RSV induced extreme hyperresponsiveness to aerosolised MCh during the acute phase of infection in adult and weanling mice. The route-specificity of hyperresponsiveness suggests that epithelial mechanisms were important in determining the physiological effects. Inflammatory changes were dissociated from physiological changes, particularly in weanling mice.

Glutathione Peroxidase-1 Reduces Influenza A Virus–Induced Lung Inflammation

Oxidative stress caused by excessive reactive oxygen species production is implicated in influenza A virus-induced lung disease. Glutathione peroxidase (GPx)-1 is an antioxidant enzyme that may protect lungs from such damage. The objective of this study was to determine if GPx-1 protects the lung against influenza A virus-induced lung inflammation in vivo. Male wild-type (WT) or GPx-1(-/-) mice were inoculated with HKx31 (H3N2, 1 × 10(4) plaque-forming units), and bronchoalveolar lavage fluid (BALF)/lung compartments were analyzed on Days 3 and 7 after infection for inflammatory marker expression, histology, and viral titer. WT mice infected with HKx31 had significantly more BALF total cells, macrophages, neutrophils, and lymphocytes at Days 3 and 7 compared with naive WT animals (n = 5-8; P < 0.05). However, infected GPx-1(-/-) mice had significantly more BALF inflammation, which included more total cells, macrophages, and neutrophils, compared with WT mice, and this was abolished by treatment with the GPx mimetic ebselen. BALF inflammation persisted in GPx-1(-/-) mice on Day 10 after infection, and GPx-1(-/-) mice had significantly more influenza-specific CD8(+) T cells in spleen compared with WT mice (n = 3-4; P < 0.05). Infected GPx-1(-/-) mice had greater peribronchial and parenchymal inflammation than WT mice, and viral titer was significantly reduced in GPx-1(-/-) mice at Day 3 (n = 5; P < 0.05). Gene expression analysis revealed that infected GPx-1(-/-) mice had higher whole lung TNF-α, macrophage inflammatory protein (MIP)-1α, MIP-2, KC, and matrix metalloproteinase (MMP)-12 mRNA compared with infected WT mice. GPx-1(-/-) mice had more MIP-2 protein in BALF at Day 3 and more active MMP-9 protease in BALF at Days 3 and 7 than WT mice. These data indicate that GPx-1 reduces influenza A virus-induced lung inflammation.

Reliability and validity of the Edinburgh Postnatal Depression Scale (EPDS) for detecting perinatal common mental disorders (PCMDs) among women in low-and lower-middle-income countries: a systematic review

BackgroundThe Edinburgh Postnatal Depression Scale (EPDS), originally developed in Britain, is one of the most widely used screening instruments for assessing symptoms of the Perinatal Common Mental Disorders (PCMDs) of depression and anxiety. However, its potential to detect PCMDs in culturally diverse low- and lower-middle income countries (LALMICs) is unclear. This systematic review aimed to appraise formally validated local language versions of the EPDS from these resource-constrained settings.MethodsFollowing the PRISMA protocol, we searched MEDLINE-OVID, CINAHL-Plus and PUBMED to identify studies reporting translation, cultural adaptation and formal validation of the EPDS to detect PCMDs among women in LALMICs. The quality of the studies meeting inclusion criteria was assessed using standard criteria and a new process-based criteria; which was developed specifically for this study.ResultsWe identified 1281 records among which 16 met inclusion criteria; three further papers were identified by hand-searching reference lists. The publications reported findings from 12 LALMICs in14 native languages. Most of these local language versions of the EPDS (LLV-EPDS) had lower precision for identifying true cases of PCMDs among women in the general perinatal population compared to the original English version. Only one study met all criteria for culturally sensitive translation, the others had not established the comprehensibility of the local version amongst representative groups of women in pre-testing. Many studies tested the LLV-EPDS only amongst convenience samples recruited at single health facilities. Diagnostic interviews for confirmation of mental disorders could have been influenced by the mental health professionals’ lack of blinding to the initial screening results. Additionally, even when diagnostic-interviews were carried out in the local language, questions might not have been understood as most studies followed standard diagnostic protocol which had not been culturally adapted.ConclusionsMost of the LLV-EPDS from non-English speaking low- and middle-income-countries did not meet all criteria for formal validation of a screening instrument. Psychometric properties of LLV-EPDS could be enhanced by adopting the new process-based criteria for translation, adaptation and validation.

Oseltamivir treatment of mice before or after mild influenza infection reduced cellular and cytokine inflammation in the lung

Please cite this paper as: Wong et al. (2011) Oseltamivir treatment of mice before or after mild influenza infection reduced cellular and cytokine inflammation in the lung. Influenza and Other Respiratory Viruses 5(5), 343–350.

Acute Influenza A infection induces bronchial hyper-responsiveness in mice

This study aimed to determine whether the route of administration of methacholine (MCh) influenced the pattern of airway hyper-responsiveness (AHR) in mice. BALB/c mice were inoculated with a 50-microL volume containing 10(4.5)-pfu Influenza virus A/Mem/1/71(H3N1) or media. MCh responsiveness in vivo [inhaled (0.01-30 mg/mL), i.v. MCh (6-48 microg/min/kg)] and in vitro were measured at day 4 post-infection (D4) during acute lower respiratory infection (LRI) and following resolution of infection at day 20 (D20) using a low-frequency, forced oscillation technique. Inflammation was assessed in bronchoalveolar lavage fluid. Infected mice had pulmonary inflammation and heightened responsiveness to both inhaled (p<0.03) and intravenous (p<0.02) MCh on D4, but not on D20. In vitro responsiveness was not altered at either time point. Influenza A LRI results in AHR during acute infection associated with a marked inflammatory response and increased permeability of the alveolar-capillary barrier. These data suggest that intrinsic muscle properties are not altered but MCh has greater access to airway smooth muscle during acute infection.

What is the contribution of respiratory viruses and lung proteases to airway remodelling in asthma and chronic obstructive pulmonary disease

Abstract It is well known that the lungs of asthmatics show airway wall remodelling and that asthma exacerbations are linked to respiratory infections. There is some evidence that respiratory infections in early childhood may increase the risk of developing asthma later in life. Chronic obstructive pulmonary disease (COPD), by definition, involves structural changes to the airways. However, very little is known about what role virus infections play in the development of this remodelling. This review considers the role of matrix metalloproteases and neutrophil elastase in remodelling, and whether the induction of proteases and other mediators during respiratory virus infections may contribute to the development of airway remodelling.

The lung inflammation and skeletal muscle wasting induced by subchronic cigarette smoke exposure are not altered by a high-fat diet in mice.

Obesity and cigarette smoking independently constitute major preventable causes of morbidity and mortality and obesity is known to worsen lung inflammation in asthma. Paradoxically, higher body mass index (BMI) is associated with reduced mortality in smoking induced COPD whereas low BMI increases mortality risk. To date, no study has investigated the effect of a dietary-induced obesity and cigarette smoke exposure on the lung inflammation and loss of skeletal muscle mass in mice. Male BALB/c mice were exposed to 4 cigarettes/day, 6 days/week for 7 weeks, or sham handled. Mice consumed either standard laboratory chow (3.5 kcal/g, 12% fat) or a high fat diet (HFD, 4.3 kcal/g, 32% fat). Mice exposed to cigarette smoke for 7 weeks had significantly more inflammatory cells in the BALF (P<0.05) and the mRNA expression of pro-inflammatory cytokines and chemokines was significantly increased (P<0.05); HFD had no effect on these parameters. Sham- and smoke-exposed mice consuming the HFD were significantly heavier than chow fed animals (12 and 13%, respectively; P<0.05). Conversely, chow and HFD fed mice exposed to cigarette smoke weighed 16 and 15% less, respectively, compared to sham animals (P<0.05). The skeletal muscles (soleus, tibialis anterior and gastrocnemius) of cigarette smoke-exposed mice weighed significantly less than sham-exposed mice (P<0.05) and the HFD had no protective effect. For the first time we report that cigarette smoke exposure significantly decreased insulin-like growth factor-1 (IGF-1) mRNA expression in the gastrocnemius and tibialis anterior and IGF-1 protein in the gastrocnemius (P<0.05). We have also shown that cigarette smoke exposure reduced circulating IGF-1 levels. IL-6 mRNA expression was significantly elevated in all three skeletal muscles of chow fed smoke-exposed mice (P<0.05). In conclusion, these findings suggest that a down-regulation in local IGF-1 may be responsible for the loss of skeletal muscle mass following cigarette smoke exposure in mice.