Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major ... more Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution. Respiratory infections are a major determinant of pulmonary morbidity in chronic obstructive pulmonary disease (COPD) Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, COPD, accounting for approximately three million deaths annually [1-4].
Chronic obstructive pulmonary disease (COPD) is a progressive and devastating chronic lung condit... more Chronic obstructive pulmonary disease (COPD) is a progressive and devastating chronic lung condition that has a significant global burden, both medically and financially. Currently there are no medications that can alter the course of disease. At best, the drugs in clinical practice provide symptomatic relief to suffering patients by alleviating acute exacerbations. Most of current clinical research activities are in late severe disease with lesser attention given to early disease manifestations. There is as yet, a lack of understanding of the underlying mechanisms of disease progression and the molecular switches that are involved in their manifestation. Small airway fibrosis and obliteration are known to cause fixed airflow obstruction in COPD, and the consequential damage to the lung has an early onset. So far, there is little evidence of the mechanisms that underlie this aspect of pathology. However, emerging research confirms that airway epithelial reprogramming or epithelial to mesenchymal transition (EMT) is a key mechanism that drives fibrotic remodelling changes in smokers and patients with COPD. A recent study by Lai et al. further highlights the importance of EMT in smoking-related COPD pathology. The authors identify HB-EGF, an EGFR ligand, as a key driver of EMT and a potential new therapeutic target for the amelioration of EMT and airway remodelling. There are also wider implications in lung cancer prophylaxis, which is another major comorbidity associated with COPD. We consider that improved molecular understanding of the intricate pathways associated with epithelial cell plasticity in smokers and patients with COPD will have major therapeutic implications.
Background: COPD is a common disease characterized by respiratory airflow obstruction. TGF-b1 and... more Background: COPD is a common disease characterized by respiratory airflow obstruction. TGF-b1 and SMAD pathway is believed to play a role in COPD pathogenesis by driving epithelial mesenchymal transition (EMT). Methods: We investigated TGF-b1 signalling and pSmad2/3 and Smad7 activity in resected small airway tissue from patients with; normal lung function and a smoking history (NLFS), current smokers and ex-smokers with COPD GOLD stage 1 and 2 (COPD-CS and COPD-ES) and compared these with normal nonsmoking controls (NC). Using immunohistochemistry, we measured activity for these markers in the epithelium, basal epithelium, and reticular basement membrane (RBM). Tissue was also stained for EMT markers E-cadherin, S100A4 and vimentin. Results: The Staining of pSMAD2/3 was significantly increased in the epithelium, and RBM of all COPD groups compared to NC (p <0.0005). There was a less significant increase in COPD-ES basal cell numbers compared to NC (p= 0.02). SMAD7 staining showed a similar pattern (p <0.0001). All COPD group levels of TGF-b1 in the epithelium, basal cells, and RBM cells were significantly lower than NC (p <0.0001). Ratio analysis showed a disproportionate increase in SMAD7 levels compared to pSMAD2/3 in NLFS, COPD-CS and COPD-ES. pSMAD negatively correlated with small airway calibre (FEF 25-75% ; p= 0.03 r=-0.36).
American Journal of Respiratory Cell and Molecular Biology, Aug 1, 2020
Quantitative computed tomography measures of pectoralis muscle area and disease severity in chron... more Quantitative computed tomography measures of pectoralis muscle area and disease severity in chronic obstructive pulmonary disease: a cross-sectional study.
et al. Increased myofibroblasts in the small airways and relation to remodelling and functional c... more et al. Increased myofibroblasts in the small airways and relation to remodelling and functional changes in smokers and COPD patients: potential role of epithelial-mesenchymal transition (EMT). ERJ Open Res 2021; in press (
Pulmonary macrophages are key to elimination of respiratory pathogens. Oxidative stress and mitoc... more Pulmonary macrophages are key to elimination of respiratory pathogens. Oxidative stress and mitochondrial dysfunction are associated with defective macrophage phagocytosis in COPD, with implications for aberrant cellular metabolism and early cell death.
Two interesting publications in the European Respiratory Journal recently by RUSSO et al. [1] and... more Two interesting publications in the European Respiratory Journal recently by RUSSO et al. [1] and LEUNG et al. [2] discuss the possible role of nicotine in this pandemic and the "furious pursuit for better therapeutics". Not surprisingly, the angiotensin-converting enzyme 2 (ACE-2) is known to be the likely host receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further, at a basic level, cellular mechanisms of nicotinic receptor activity promote SARS-CoV-2 entry and proliferation in epithelial cells through co-expression of ACE-2. Hence, this is the theory postulated by OLDS and KABBANI [3] for how nicotine consumption represents a special risk factor in coronavirus disease 2019 (COVID-19). On the other hand, and very surprisingly, Changeux et al. [4] hypothesise that the nicotinic receptor also plays a key role in the pathophysiology and might represent a target for the prevention and control of COVID-19 infection. Again, on a basic level, the hypothesis is that the SARS-CoV-2 virus is a nicotinic agent which competes with nicotine for the receptor. The backbone of this hypothesis proposes that under controlled settings, nicotinic agents (such as nicotine patches) could provide an efficient treatment for an acute infection such as COVID-19. So, tenuously, is the argument centred around the need for data about alternative nicotine delivery systems and their risk/benefit ratio in relation to COVID-19 [5]? Possibly, but are there perhaps other ways…? Soluble ACE-2 might impact viral spread, since binding to soluble receptor has been shown to block SARS-CoV-2 entry. BATLLE et al. [6] argue that, if given in its soluble form as an appropriate recombinant ACE-2 protein, this may represent a new tool to combat the spread of COVID-19. Similarly, GUO et al. [7] opined that exogenous supplement of recombinant human (rh)ACE-2 might be a brilliant idea in the treatment of COVID-19. Here the soluble ACE-2 may act as the bait to neutralise the spike protein on the surface of the SARS-CoV-2, thus inhibiting entry. Further, GUO et al. [7] referenced a recent study that demonstrated fusion protein of rhACE-2 (with an Fc fragment) showing high affinity binding to the receptor-binding domain of SARS-CoV-2. This, again, provides a basis for further drug development as fusion protein technology has been very successfully deployed in various therapeutic areas, such as rheumatology and haemophilia.
International Journal of Chronic Obstructive Pulmonary Disease, 2022
Background: Smokers and patients with COPD are highly susceptible to SARS-CoV-2 infection, leadin... more Background: Smokers and patients with COPD are highly susceptible to SARS-CoV-2 infection, leading to severe COVID-19. Methods: This cross-sectional study involved resected lung tissues from 16 patients with GOLD stage I or II COPD; of which 8 were current smokers COPD (COPD-CS), and 8 ex-smokers COPD (COPD-ES), 7 normal lung function smokers (NLFS), 9 patients with small airways disease (SAD), and 10 were never-smoking normal controls (NC). Immunostaining for ACE2, Furin, and TMPRSS2 was performed and analysed for percent expression in small airway epithelium (SAE) and counts for positively and negatively stained type 2 pneumocytes and alveolar macrophages (AMs) were done using Image ProPlus V7.0. Furthermore, primary small airway epithelial cells (pSAEC) were analysed by immunofluorescence after exposure to cigarette smoke extract (CSE). Results: ACE2, Furin, and TMPRSS2 expression significantly increased in SAE and type 2 pneumocytes in all the subjects (except Furin for NLFS) compared to NC (p < 0.001). Similar significance was observed for ACE2 positive AM (p < 0.002), except COPD-ES, which decreased in ACE2 positive AMs (p < 0.003). Total type 2 pneumocytes and AMs significantly increased in the pathological groups compared to NC (p < 0.01), except SAD (p = 0.08). However, AMs are significantly reduced in COPD-ES (p < 0.003). Significant changes were observed for tissue co-expression of Furin and TMPRSS2 with ACE2 in SAE, type 2 pneumocytes and AMs. These markers also negatively correlated with lung function parameters, such as FEV 1 /FVC % predicted, FEF25-75%, DLCO% predicted. A strong co-localisation and expression for ACE2 (p < 0.0001), Furin (p < 0.01), and TMPRSS2 (p < 0.0001) was observed in pSAEC treated with 1% CSE than controls. Discussion: The increased expression of ACE2, TMPRSS2 and Furin, in the SAE, type 2 pneumocytes and AMs of smokers and COPD are detrimental to lung function and proves that these patient groups could be more susceptible to severe COVID-19 infection. Increased type 2 pneumocytes suggest that these patients are vulnerable to developing post-COVID-19 interstitial pulmonary fibrosis or fibrosis in general. There could be a silently developing interstitial pathology in smokers and patients with COPD. This is the first comprehensive study to report such changes.
We read with great interest the recent original research article by RAYMAKERS et al. [1] publishe... more We read with great interest the recent original research article by RAYMAKERS et al. [1] published in the European Respiratory Journal, regarding the beneficial effects of inhaled corticosteroids (ICS) in reducing the lung cancer risk in patients with chronic obstructive pulmonary disease (COPD). In their discussion, the authors mentioned that the mechanisms by which COPD is associated with an increased risk of lung cancer are not well-established. We do not know which mechanisms ICS inhibit for an appreciable reduction in lung cancer risk. This is a hugely important area and it is encouraging that leading respiratory journals are recognising this. Understanding these interactive mechanisms, we believe, is very important for better future translational approaches to establish early and preventive therapy [2, 3]. We would like to take this further and suggest a broader discussion on the latest findings in COPD pathology involving processes such as epithelial mesenchymal transition (EMT), angiogenesis and airway wall cellularity, and the effects of ICS on these aspects in COPD.
International Journal of Chronic Obstructive Pulmonary Disease, Jul 1, 2019
COPD is a common and highly destructive disease with huge impacts on people and health services t... more COPD is a common and highly destructive disease with huge impacts on people and health services throughout the world. It is mainly caused by cigarette smoking though environmental pollution is also significant. There are no current treatments that affect the overall course of COPD; current drugs focus on symptomatic relief and to some extent reducing exacerbation rates. There is an urgent need for in-depth studies of the fundamental pathogenic mechanisms that underpin COPD. This is vital, given the fact that nearly 40%-60% of the small airway and alveolar damage occurs in COPD well before the first measurable changes in lung function are detected. These individuals are also at a high risk of lung cancer. Current COPD research is mostly centered around late disease and/or innate immune activation within the airway lumen, but the actual damage to the airway wall has early onset. COPD is the end result of complex mechanisms, possibly triggered through initial epithelial activation. To change the disease trajectory, it is crucial to understand the mechanisms in the epithelium that are switched on early in smokers. One such mechanism we believe is the process of epithelial to mesenchymal transition. This article highlights the importance of this profound epithelial cell plasticity in COPD and also its regulation. We consider that understanding early changes in COPD will open new windows for therapy.
Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (C... more Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (COPD) which is correlated with disease severity and negatively impact lung function in these patients. Thus, there is clear unmet clinical need for finding new therapies which can target airway remodeling and disease progression in COPD. Apoptosis signal-regulating kinase 1 (ASK1) is a ubiquitously expressed mitogen-activated protein kinase kinase kinase (MAP3K) activated by various stress stimuli, including reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS) and is known to regulate cell proliferation. ASM cells from COPD patients are hyper-proliferative to mitogens in vitro. However, the role of ASK1 in ASM growth is not established. Here, we aim to determine the effects of ASK1 inhibition on ASM growth and pro-mitogenic signaling using ASM cells from COPD patients. We found greater expression of ASK1 in ASM-bundles of COPD lung when compared with non-COPD. Pre
European Respiratory Journal, which summarises the findings of a Cochrane review on electronic ci... more European Respiratory Journal, which summarises the findings of a Cochrane review on electronic cigarettes for smoking cessation [2]. We strongly agree with PISINGER and VESTBO [1] that the authors have not presented a balanced scientific view and have overlooked the dangers of early, such as e-cigarette or vaping associated lung injury (EVALI), and long-term electronic cigarette use. This is an important public health issue, and we would like to further enhance this discussion.
American Journal of Physiology-lung Cellular and Molecular Physiology, 2022
Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functio... more Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functional abnormalities, with airway obstruction common in both diseases. Asthma COPD overlap (ACO) does not define a single disease but is a descriptive term for clinical use that includes several overlapping clinical phenotypes of chronic airways disease with different underlying mechanisms. This literature review was initiated to describe published studies, identify gaps in knowledge, and propose future research goals regarding the disease pathology of ACO, especially the airway remodeling changes and inflammation aspects. Airway remodeling occurs in asthma and COPD, but there are differences in the structures affected and the prime anatomic site at which they occur. Reticular basement membrane thickening and cellular infiltration with eosinophils and T-helper (CD4+) lymphocytes are prominent features of asthma. Epithelial squamous metaplasia, airway wall fibrosis, emphysema, bronchoalveolar lavage (BAL) neutrophilia, and (CD8+) T-cytotoxic lymphocyte infiltrations in the airway wall are features of COPD. There is no universally accepted definition of ACO, nor are there clearly defined pathological characteristics to differentiate from asthma and COPD. Understanding etiological concepts within the purview of inflammation and airway remodeling changes in ACO would allow better management of these patients.
The International Journal of Biochemistry & Cell Biology, Aug 1, 2021
Following the emergence of electronic cigarette, or vaping product use associated lung injury (EV... more Following the emergence of electronic cigarette, or vaping product use associated lung injury (EVALI) in 2019 in the US, regulation of e-cigarettes has become globally tighter and the collective evidence of the detrimental effects of vaping has grown. The danger of cellular distress and altered homeostasis is heavily associated with the modifiable nature of electronic cigarette devices. An array of harmful chemicals and elevated concentrations of metals have been detected in e-cigarette aerosols which have been linked to various pathogeneses. Vaping is linked to increased inflammation, altered lipid homeostasis and mitochondrial dysfunction whilst also increasing microbial susceptibility whilst the long-term damage is yet to be observed. The scientific evidence is mounting and highlighting that, along with traditional tobacco cigarette smoking, electronic cigarette vaping is not a safe practice.
Expert Review of Respiratory Medicine, Jul 28, 2020
Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible fib... more Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible fibrotic disease associated with respiratory failure. The disease remains idiopathic, but repeated alveolar epithelium injury, disruption of alveolar-capillary integrity, abnormal vascular repair, and pulmonary vascular remodelling are considered possible pathogenic mechanisms. Also, the development of comorbidities such as pulmonary hypertension (PH) could further impact disease outcome, quality of life and survival rates in IPF. Areas Covered: The current review provides a comprehensive literature survey of the mechanisms involved in the development and manifestations of IPF and their links to PH pathology. This review also provides the current understanding of molecular mechanisms that link the two pathologies and will specifically decipher the role of endothelial to mesenchymal transition (EndMT) along with the possible triggers of EndMT. The possibility of targeting EndMT as a therapeutic option in IPF is discussed. Expert Opinion: With a steady increase in prevalence and mortality, IPF is no longer considered a rare disease. Thus, it is of utmost importance and urgency that the underlying profibrotic pathways and mechanisms are fully understood, to enable the development of novel therapeutic strategies.
RATIONALE Tobacco smoking, via nicotine receptor (α7 nAChR), increases risk for the susceptibilit... more RATIONALE Tobacco smoking, via nicotine receptor (α7 nAChR), increases risk for the susceptibility to infection from SARS-CoV-2 via increased expression of ACE2 in the lung. Given the modifiable nature and high risk of electronic cigarettes, with potential to deliver toxic concentrations of nicotine, we investigated if electronic cigarettes are also a danger in relation to COVID-19. We investigated the cytotoxicity of electronic cigarette exposure and whether flavored vaping has the potential to increase susceptibility to SARS-CoV-2 infection in large and small airway epithelial cells through the upregulation of ACE2. METHODS We exposed bronchial epithelial (BEAS-2B) and primary human small airway epithelial (SAEC) cells to e-cigarette aerosol condensates produced from propylene glycol/vegetable glycerin (PG/VG) or locally bought [Juicius Maximus, watermelon flavor (WM)] e-liquid (± added nicotine), and cigarette smoke extract (CSE). Aerosols were produced from a Drag2 e-cigarette device (Vapoo) operated at 60W, with a 0.4Ω U2 dual coil (Vapoo), and condensates were collected in flasks over dry ice with the aid of a peristaltic pump, then stored at -80°C. We investigated if e-cigarette exposure, alike cigarette smoke, increases the expression of ACE2 in lung epithelial cells. Cytotoxicity (CCK-8), membrane integrity by lactate dehydrogenase (LDH) release, and ACE2 protein expression (immunofluorescence) were measured for both 4- and 24-hour treatments;ACE2 gene expression was measured using qPCR for 4- hour treatment only. RESULTSFor both BEAS-2B cells and SAECs, nicotine-free condensates and higher concentrations of nicotine-containing condensates were highly cytotoxic (PG/VG, JM ± nicotine(60mg);∗∗∗p&lt;0.0001, ∗∗∗p&lt;0.001). Higher LDH release was seen in BEAS-2B cells treated for 24 hours with higher concentrations of nicotine-containing condensates (PG/VG, JM + nicotine(18 or 60mg): ∗∗∗∗p&lt;0.0001, ∗∗p&lt;0.01) indicating that the membrane integrity was disturbed. Cells appear to be under significant distress. Small increases in LDH were also seen with 4 hours treatment (∗∗∗∗p&lt;0.0001, ∗∗∗p&lt;0.001, ∗∗p&lt;0.01∗p&lt;0.05). ACE2 protein expression was observably increased in all treatments compared to media controls, particularly for 24 hours exposures. ACE2 gene expression was significantly increased in cells exposed to WM + 60mg/mL nicotine (∗∗p&lt;0.1) and cigarette smoke extract (∗∗∗∗p&lt;0.0001) compared with media controls. CONCLUSIONS Our study confirms that electronic cigarettes condensates are highly cytotoxic. Data also suggests that vaping can result in an increase in lung ACE2 expression as we have shown for tobacco smoking. The health care community needs to stay alert;vaping and smoking are avoidable risk factors for SARS-CoV-2 infection and should be avoided during and post- the COVID-19 pandemic.
BackgroundCOPD is the third leading cause of death worldwide. Cigarette smoke (CS)-induced chroni... more BackgroundCOPD is the third leading cause of death worldwide. Cigarette smoke (CS)-induced chronic inflammation inducing airway remodelling, emphysema and impaired lung function is the primary cause. Effective therapies are urgently needed. Human chymase (hCMA)1 and its orthologue mCMA1/mouse mast cell protease (mMCP)5 are exocytosed from activated mast cells and have adverse roles in numerous disorders, but their role in COPD is unknown.MethodsWe evaluated hCMA1 levels in lung tissues of COPD patients. We usedmmcp5-deficient (−/−) mice to evaluate this protease's role and potential for therapeutic targeting in CS-induced experimental COPD. In addition, we usedex vivo/in vitrostudies to define mechanisms.ResultsThe levels of hCMA1 mRNA and CMA1+mast cells were increased in lung tissues from severe compared to early/mild COPD patients, non-COPD smokers and healthy controls. Degranulated mast cell numbers and mMCP5 protein were increased in lung tissues of wild-type mice with experimental COPD.mmcp5−/−mice were protected against CS-induced inflammation and macrophage accumulation, airway remodelling, emphysema and impaired lung function in experimental COPD. CS extract challenge of co-cultures of mast cells from wild-type, but notmmcp5−/−mice with wild-type lung macrophages increased in tumour necrosis factor (TNF)-α release. It also caused the release of CMA1 from human mast cells, and recombinant hCMA-1 induced TNF-α release from human macrophages. Treatment with CMA1 inhibitor potently suppressed these hallmark features of experimental COPD.ConclusionCMA1/mMCP5 promotes the pathogenesis of COPD, in part, by inducing TNF-α expression and release from lung macrophages. Inhibiting hCMA1 may be a novel treatment for COPD.
Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major ... more Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution. Respiratory infections are a major determinant of pulmonary morbidity in chronic obstructive pulmonary disease (COPD) Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, COPD, accounting for approximately three million deaths annually [1-4].
Chronic obstructive pulmonary disease (COPD) is a progressive and devastating chronic lung condit... more Chronic obstructive pulmonary disease (COPD) is a progressive and devastating chronic lung condition that has a significant global burden, both medically and financially. Currently there are no medications that can alter the course of disease. At best, the drugs in clinical practice provide symptomatic relief to suffering patients by alleviating acute exacerbations. Most of current clinical research activities are in late severe disease with lesser attention given to early disease manifestations. There is as yet, a lack of understanding of the underlying mechanisms of disease progression and the molecular switches that are involved in their manifestation. Small airway fibrosis and obliteration are known to cause fixed airflow obstruction in COPD, and the consequential damage to the lung has an early onset. So far, there is little evidence of the mechanisms that underlie this aspect of pathology. However, emerging research confirms that airway epithelial reprogramming or epithelial to mesenchymal transition (EMT) is a key mechanism that drives fibrotic remodelling changes in smokers and patients with COPD. A recent study by Lai et al. further highlights the importance of EMT in smoking-related COPD pathology. The authors identify HB-EGF, an EGFR ligand, as a key driver of EMT and a potential new therapeutic target for the amelioration of EMT and airway remodelling. There are also wider implications in lung cancer prophylaxis, which is another major comorbidity associated with COPD. We consider that improved molecular understanding of the intricate pathways associated with epithelial cell plasticity in smokers and patients with COPD will have major therapeutic implications.
Background: COPD is a common disease characterized by respiratory airflow obstruction. TGF-b1 and... more Background: COPD is a common disease characterized by respiratory airflow obstruction. TGF-b1 and SMAD pathway is believed to play a role in COPD pathogenesis by driving epithelial mesenchymal transition (EMT). Methods: We investigated TGF-b1 signalling and pSmad2/3 and Smad7 activity in resected small airway tissue from patients with; normal lung function and a smoking history (NLFS), current smokers and ex-smokers with COPD GOLD stage 1 and 2 (COPD-CS and COPD-ES) and compared these with normal nonsmoking controls (NC). Using immunohistochemistry, we measured activity for these markers in the epithelium, basal epithelium, and reticular basement membrane (RBM). Tissue was also stained for EMT markers E-cadherin, S100A4 and vimentin. Results: The Staining of pSMAD2/3 was significantly increased in the epithelium, and RBM of all COPD groups compared to NC (p <0.0005). There was a less significant increase in COPD-ES basal cell numbers compared to NC (p= 0.02). SMAD7 staining showed a similar pattern (p <0.0001). All COPD group levels of TGF-b1 in the epithelium, basal cells, and RBM cells were significantly lower than NC (p <0.0001). Ratio analysis showed a disproportionate increase in SMAD7 levels compared to pSMAD2/3 in NLFS, COPD-CS and COPD-ES. pSMAD negatively correlated with small airway calibre (FEF 25-75% ; p= 0.03 r=-0.36).
American Journal of Respiratory Cell and Molecular Biology, Aug 1, 2020
Quantitative computed tomography measures of pectoralis muscle area and disease severity in chron... more Quantitative computed tomography measures of pectoralis muscle area and disease severity in chronic obstructive pulmonary disease: a cross-sectional study.
et al. Increased myofibroblasts in the small airways and relation to remodelling and functional c... more et al. Increased myofibroblasts in the small airways and relation to remodelling and functional changes in smokers and COPD patients: potential role of epithelial-mesenchymal transition (EMT). ERJ Open Res 2021; in press (
Pulmonary macrophages are key to elimination of respiratory pathogens. Oxidative stress and mitoc... more Pulmonary macrophages are key to elimination of respiratory pathogens. Oxidative stress and mitochondrial dysfunction are associated with defective macrophage phagocytosis in COPD, with implications for aberrant cellular metabolism and early cell death.
Two interesting publications in the European Respiratory Journal recently by RUSSO et al. [1] and... more Two interesting publications in the European Respiratory Journal recently by RUSSO et al. [1] and LEUNG et al. [2] discuss the possible role of nicotine in this pandemic and the "furious pursuit for better therapeutics". Not surprisingly, the angiotensin-converting enzyme 2 (ACE-2) is known to be the likely host receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further, at a basic level, cellular mechanisms of nicotinic receptor activity promote SARS-CoV-2 entry and proliferation in epithelial cells through co-expression of ACE-2. Hence, this is the theory postulated by OLDS and KABBANI [3] for how nicotine consumption represents a special risk factor in coronavirus disease 2019 (COVID-19). On the other hand, and very surprisingly, Changeux et al. [4] hypothesise that the nicotinic receptor also plays a key role in the pathophysiology and might represent a target for the prevention and control of COVID-19 infection. Again, on a basic level, the hypothesis is that the SARS-CoV-2 virus is a nicotinic agent which competes with nicotine for the receptor. The backbone of this hypothesis proposes that under controlled settings, nicotinic agents (such as nicotine patches) could provide an efficient treatment for an acute infection such as COVID-19. So, tenuously, is the argument centred around the need for data about alternative nicotine delivery systems and their risk/benefit ratio in relation to COVID-19 [5]? Possibly, but are there perhaps other ways…? Soluble ACE-2 might impact viral spread, since binding to soluble receptor has been shown to block SARS-CoV-2 entry. BATLLE et al. [6] argue that, if given in its soluble form as an appropriate recombinant ACE-2 protein, this may represent a new tool to combat the spread of COVID-19. Similarly, GUO et al. [7] opined that exogenous supplement of recombinant human (rh)ACE-2 might be a brilliant idea in the treatment of COVID-19. Here the soluble ACE-2 may act as the bait to neutralise the spike protein on the surface of the SARS-CoV-2, thus inhibiting entry. Further, GUO et al. [7] referenced a recent study that demonstrated fusion protein of rhACE-2 (with an Fc fragment) showing high affinity binding to the receptor-binding domain of SARS-CoV-2. This, again, provides a basis for further drug development as fusion protein technology has been very successfully deployed in various therapeutic areas, such as rheumatology and haemophilia.
International Journal of Chronic Obstructive Pulmonary Disease, 2022
Background: Smokers and patients with COPD are highly susceptible to SARS-CoV-2 infection, leadin... more Background: Smokers and patients with COPD are highly susceptible to SARS-CoV-2 infection, leading to severe COVID-19. Methods: This cross-sectional study involved resected lung tissues from 16 patients with GOLD stage I or II COPD; of which 8 were current smokers COPD (COPD-CS), and 8 ex-smokers COPD (COPD-ES), 7 normal lung function smokers (NLFS), 9 patients with small airways disease (SAD), and 10 were never-smoking normal controls (NC). Immunostaining for ACE2, Furin, and TMPRSS2 was performed and analysed for percent expression in small airway epithelium (SAE) and counts for positively and negatively stained type 2 pneumocytes and alveolar macrophages (AMs) were done using Image ProPlus V7.0. Furthermore, primary small airway epithelial cells (pSAEC) were analysed by immunofluorescence after exposure to cigarette smoke extract (CSE). Results: ACE2, Furin, and TMPRSS2 expression significantly increased in SAE and type 2 pneumocytes in all the subjects (except Furin for NLFS) compared to NC (p < 0.001). Similar significance was observed for ACE2 positive AM (p < 0.002), except COPD-ES, which decreased in ACE2 positive AMs (p < 0.003). Total type 2 pneumocytes and AMs significantly increased in the pathological groups compared to NC (p < 0.01), except SAD (p = 0.08). However, AMs are significantly reduced in COPD-ES (p < 0.003). Significant changes were observed for tissue co-expression of Furin and TMPRSS2 with ACE2 in SAE, type 2 pneumocytes and AMs. These markers also negatively correlated with lung function parameters, such as FEV 1 /FVC % predicted, FEF25-75%, DLCO% predicted. A strong co-localisation and expression for ACE2 (p < 0.0001), Furin (p < 0.01), and TMPRSS2 (p < 0.0001) was observed in pSAEC treated with 1% CSE than controls. Discussion: The increased expression of ACE2, TMPRSS2 and Furin, in the SAE, type 2 pneumocytes and AMs of smokers and COPD are detrimental to lung function and proves that these patient groups could be more susceptible to severe COVID-19 infection. Increased type 2 pneumocytes suggest that these patients are vulnerable to developing post-COVID-19 interstitial pulmonary fibrosis or fibrosis in general. There could be a silently developing interstitial pathology in smokers and patients with COPD. This is the first comprehensive study to report such changes.
We read with great interest the recent original research article by RAYMAKERS et al. [1] publishe... more We read with great interest the recent original research article by RAYMAKERS et al. [1] published in the European Respiratory Journal, regarding the beneficial effects of inhaled corticosteroids (ICS) in reducing the lung cancer risk in patients with chronic obstructive pulmonary disease (COPD). In their discussion, the authors mentioned that the mechanisms by which COPD is associated with an increased risk of lung cancer are not well-established. We do not know which mechanisms ICS inhibit for an appreciable reduction in lung cancer risk. This is a hugely important area and it is encouraging that leading respiratory journals are recognising this. Understanding these interactive mechanisms, we believe, is very important for better future translational approaches to establish early and preventive therapy [2, 3]. We would like to take this further and suggest a broader discussion on the latest findings in COPD pathology involving processes such as epithelial mesenchymal transition (EMT), angiogenesis and airway wall cellularity, and the effects of ICS on these aspects in COPD.
International Journal of Chronic Obstructive Pulmonary Disease, Jul 1, 2019
COPD is a common and highly destructive disease with huge impacts on people and health services t... more COPD is a common and highly destructive disease with huge impacts on people and health services throughout the world. It is mainly caused by cigarette smoking though environmental pollution is also significant. There are no current treatments that affect the overall course of COPD; current drugs focus on symptomatic relief and to some extent reducing exacerbation rates. There is an urgent need for in-depth studies of the fundamental pathogenic mechanisms that underpin COPD. This is vital, given the fact that nearly 40%-60% of the small airway and alveolar damage occurs in COPD well before the first measurable changes in lung function are detected. These individuals are also at a high risk of lung cancer. Current COPD research is mostly centered around late disease and/or innate immune activation within the airway lumen, but the actual damage to the airway wall has early onset. COPD is the end result of complex mechanisms, possibly triggered through initial epithelial activation. To change the disease trajectory, it is crucial to understand the mechanisms in the epithelium that are switched on early in smokers. One such mechanism we believe is the process of epithelial to mesenchymal transition. This article highlights the importance of this profound epithelial cell plasticity in COPD and also its regulation. We consider that understanding early changes in COPD will open new windows for therapy.
Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (C... more Increased airway smooth muscle (ASM) mass is observed in chronic obstructive pulmonary disease (COPD) which is correlated with disease severity and negatively impact lung function in these patients. Thus, there is clear unmet clinical need for finding new therapies which can target airway remodeling and disease progression in COPD. Apoptosis signal-regulating kinase 1 (ASK1) is a ubiquitously expressed mitogen-activated protein kinase kinase kinase (MAP3K) activated by various stress stimuli, including reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS) and is known to regulate cell proliferation. ASM cells from COPD patients are hyper-proliferative to mitogens in vitro. However, the role of ASK1 in ASM growth is not established. Here, we aim to determine the effects of ASK1 inhibition on ASM growth and pro-mitogenic signaling using ASM cells from COPD patients. We found greater expression of ASK1 in ASM-bundles of COPD lung when compared with non-COPD. Pre
European Respiratory Journal, which summarises the findings of a Cochrane review on electronic ci... more European Respiratory Journal, which summarises the findings of a Cochrane review on electronic cigarettes for smoking cessation [2]. We strongly agree with PISINGER and VESTBO [1] that the authors have not presented a balanced scientific view and have overlooked the dangers of early, such as e-cigarette or vaping associated lung injury (EVALI), and long-term electronic cigarette use. This is an important public health issue, and we would like to further enhance this discussion.
American Journal of Physiology-lung Cellular and Molecular Physiology, 2022
Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functio... more Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functional abnormalities, with airway obstruction common in both diseases. Asthma COPD overlap (ACO) does not define a single disease but is a descriptive term for clinical use that includes several overlapping clinical phenotypes of chronic airways disease with different underlying mechanisms. This literature review was initiated to describe published studies, identify gaps in knowledge, and propose future research goals regarding the disease pathology of ACO, especially the airway remodeling changes and inflammation aspects. Airway remodeling occurs in asthma and COPD, but there are differences in the structures affected and the prime anatomic site at which they occur. Reticular basement membrane thickening and cellular infiltration with eosinophils and T-helper (CD4+) lymphocytes are prominent features of asthma. Epithelial squamous metaplasia, airway wall fibrosis, emphysema, bronchoalveolar lavage (BAL) neutrophilia, and (CD8+) T-cytotoxic lymphocyte infiltrations in the airway wall are features of COPD. There is no universally accepted definition of ACO, nor are there clearly defined pathological characteristics to differentiate from asthma and COPD. Understanding etiological concepts within the purview of inflammation and airway remodeling changes in ACO would allow better management of these patients.
The International Journal of Biochemistry & Cell Biology, Aug 1, 2021
Following the emergence of electronic cigarette, or vaping product use associated lung injury (EV... more Following the emergence of electronic cigarette, or vaping product use associated lung injury (EVALI) in 2019 in the US, regulation of e-cigarettes has become globally tighter and the collective evidence of the detrimental effects of vaping has grown. The danger of cellular distress and altered homeostasis is heavily associated with the modifiable nature of electronic cigarette devices. An array of harmful chemicals and elevated concentrations of metals have been detected in e-cigarette aerosols which have been linked to various pathogeneses. Vaping is linked to increased inflammation, altered lipid homeostasis and mitochondrial dysfunction whilst also increasing microbial susceptibility whilst the long-term damage is yet to be observed. The scientific evidence is mounting and highlighting that, along with traditional tobacco cigarette smoking, electronic cigarette vaping is not a safe practice.
Expert Review of Respiratory Medicine, Jul 28, 2020
Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible fib... more Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible fibrotic disease associated with respiratory failure. The disease remains idiopathic, but repeated alveolar epithelium injury, disruption of alveolar-capillary integrity, abnormal vascular repair, and pulmonary vascular remodelling are considered possible pathogenic mechanisms. Also, the development of comorbidities such as pulmonary hypertension (PH) could further impact disease outcome, quality of life and survival rates in IPF. Areas Covered: The current review provides a comprehensive literature survey of the mechanisms involved in the development and manifestations of IPF and their links to PH pathology. This review also provides the current understanding of molecular mechanisms that link the two pathologies and will specifically decipher the role of endothelial to mesenchymal transition (EndMT) along with the possible triggers of EndMT. The possibility of targeting EndMT as a therapeutic option in IPF is discussed. Expert Opinion: With a steady increase in prevalence and mortality, IPF is no longer considered a rare disease. Thus, it is of utmost importance and urgency that the underlying profibrotic pathways and mechanisms are fully understood, to enable the development of novel therapeutic strategies.
RATIONALE Tobacco smoking, via nicotine receptor (α7 nAChR), increases risk for the susceptibilit... more RATIONALE Tobacco smoking, via nicotine receptor (α7 nAChR), increases risk for the susceptibility to infection from SARS-CoV-2 via increased expression of ACE2 in the lung. Given the modifiable nature and high risk of electronic cigarettes, with potential to deliver toxic concentrations of nicotine, we investigated if electronic cigarettes are also a danger in relation to COVID-19. We investigated the cytotoxicity of electronic cigarette exposure and whether flavored vaping has the potential to increase susceptibility to SARS-CoV-2 infection in large and small airway epithelial cells through the upregulation of ACE2. METHODS We exposed bronchial epithelial (BEAS-2B) and primary human small airway epithelial (SAEC) cells to e-cigarette aerosol condensates produced from propylene glycol/vegetable glycerin (PG/VG) or locally bought [Juicius Maximus, watermelon flavor (WM)] e-liquid (± added nicotine), and cigarette smoke extract (CSE). Aerosols were produced from a Drag2 e-cigarette device (Vapoo) operated at 60W, with a 0.4Ω U2 dual coil (Vapoo), and condensates were collected in flasks over dry ice with the aid of a peristaltic pump, then stored at -80°C. We investigated if e-cigarette exposure, alike cigarette smoke, increases the expression of ACE2 in lung epithelial cells. Cytotoxicity (CCK-8), membrane integrity by lactate dehydrogenase (LDH) release, and ACE2 protein expression (immunofluorescence) were measured for both 4- and 24-hour treatments;ACE2 gene expression was measured using qPCR for 4- hour treatment only. RESULTSFor both BEAS-2B cells and SAECs, nicotine-free condensates and higher concentrations of nicotine-containing condensates were highly cytotoxic (PG/VG, JM ± nicotine(60mg);∗∗∗p&lt;0.0001, ∗∗∗p&lt;0.001). Higher LDH release was seen in BEAS-2B cells treated for 24 hours with higher concentrations of nicotine-containing condensates (PG/VG, JM + nicotine(18 or 60mg): ∗∗∗∗p&lt;0.0001, ∗∗p&lt;0.01) indicating that the membrane integrity was disturbed. Cells appear to be under significant distress. Small increases in LDH were also seen with 4 hours treatment (∗∗∗∗p&lt;0.0001, ∗∗∗p&lt;0.001, ∗∗p&lt;0.01∗p&lt;0.05). ACE2 protein expression was observably increased in all treatments compared to media controls, particularly for 24 hours exposures. ACE2 gene expression was significantly increased in cells exposed to WM + 60mg/mL nicotine (∗∗p&lt;0.1) and cigarette smoke extract (∗∗∗∗p&lt;0.0001) compared with media controls. CONCLUSIONS Our study confirms that electronic cigarettes condensates are highly cytotoxic. Data also suggests that vaping can result in an increase in lung ACE2 expression as we have shown for tobacco smoking. The health care community needs to stay alert;vaping and smoking are avoidable risk factors for SARS-CoV-2 infection and should be avoided during and post- the COVID-19 pandemic.
BackgroundCOPD is the third leading cause of death worldwide. Cigarette smoke (CS)-induced chroni... more BackgroundCOPD is the third leading cause of death worldwide. Cigarette smoke (CS)-induced chronic inflammation inducing airway remodelling, emphysema and impaired lung function is the primary cause. Effective therapies are urgently needed. Human chymase (hCMA)1 and its orthologue mCMA1/mouse mast cell protease (mMCP)5 are exocytosed from activated mast cells and have adverse roles in numerous disorders, but their role in COPD is unknown.MethodsWe evaluated hCMA1 levels in lung tissues of COPD patients. We usedmmcp5-deficient (−/−) mice to evaluate this protease's role and potential for therapeutic targeting in CS-induced experimental COPD. In addition, we usedex vivo/in vitrostudies to define mechanisms.ResultsThe levels of hCMA1 mRNA and CMA1+mast cells were increased in lung tissues from severe compared to early/mild COPD patients, non-COPD smokers and healthy controls. Degranulated mast cell numbers and mMCP5 protein were increased in lung tissues of wild-type mice with experimental COPD.mmcp5−/−mice were protected against CS-induced inflammation and macrophage accumulation, airway remodelling, emphysema and impaired lung function in experimental COPD. CS extract challenge of co-cultures of mast cells from wild-type, but notmmcp5−/−mice with wild-type lung macrophages increased in tumour necrosis factor (TNF)-α release. It also caused the release of CMA1 from human mast cells, and recombinant hCMA-1 induced TNF-α release from human macrophages. Treatment with CMA1 inhibitor potently suppressed these hallmark features of experimental COPD.ConclusionCMA1/mMCP5 promotes the pathogenesis of COPD, in part, by inducing TNF-α expression and release from lung macrophages. Inhibiting hCMA1 may be a novel treatment for COPD.
Uploads
Papers by Mathew Eapen