Differential airway remodeling changes were observed in patients with asthma COPD overlap compared to patients with asthma and COPD alone.

Management of patients with asthma COPD overlap (ACO) is clinically challenging due to insufficient evidence of pathological changes in these patients. In this cross-sectional study, we evaluated airway remodeling in endobronchial biopsies from a total of 90 subjects, which included 12 ACO, 14 patients with asthma, 12 COPD exsmokers (ES), 11 current smokers (CS), 28 healthy controls (HC), and 13 normal lung function smokers (NLFS). Tissue was stained with Masson's trichrome. Epithelium, goblet cells, reticular basement membrane (RBM), cellularity, lamina propria (LP), and smooth muscle (SM) changes were measured using Image-Pro Plus v7 software. Differential airway remodeling pattern was seen in patients with ACO. A limited change was noted in the ACO epithelium compared with other pathological groups. RBM was substantially thicker in patients with ACO than in HC (P < 0.0002) and tended to be thicker than in patients with asthma and NLFS. The total RBM cells were higher in ACO than in the HC (P < 0.0001), COPD-CS (P = 0.0559), -ES (P = 0.0345), and NLFS (P < 0.0002), but did not differ from patients with asthma. Goblet cells were higher in the ACO than in the HC (P = 0.0028) and COPD-ES (P = 0.0081). The total LP cells in ACO appeared to be higher than in HC, COPD-CS, and NLFS but appeared to be lower than in patients with asthma. Finally, SM area was significantly lower in the ACO than in patients with asthma (P = 0.001), COPD-CS (=0.0290), and NLFS (P = 0.0011). This first comprehensive study suggests that patients with ACO had distinguishable tissue remodeling that appeared to be more severe than patients with asthma and COPD. This study will help in informed decision-making for better patient management in clinical practice.

Transforming growth factor-ß1 and SMAD signalling pathway in the small airways of smokers and patients with COPD: potential role in driving fibrotic type-2 epithelial mesenchymal transition.

Background: COPD is a common disease characterized by respiratory airflow obstruction. TGF-ß1 and SMAD pathway is believed to play a role in COPD pathogenesis by driving epithelial mesenchymal transition (EMT). Methods: We investigated TGF-ß1 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 non-smoking 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-ß1 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 (FEF25-75%; p= 0.03 r= -0.36). EMT markers were active in the small airway epithelium of all the pathological groups compared to patients with COPD. Conclusion: Activation of the SMAD pathway via pSMAD2/3 is triggered by smoking and active in patients with mild to moderate COPD. These changes correlated to decline in lung function. Activation of the SMADs in the small airways is independent of TGF-ß1, suggesting factors other than TGF-ß1 are driving these pathways. These factors may have implications for small airway pathology in smokers and COPD through the process of EMT, however more mechanistic work is needed to prove these correlations.

SARS-CoV-2 (COVID-19) Adhesion Site Protein Upregulation in Small Airways, Type 2 Pneumocytes, and Alveolar Macrophages of Smokers and COPD - Possible Implications for Interstitial Fibrosis.

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 FEV1/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.

Angiotensin-Converting Enzyme 2 (ACE2), Transmembrane Peptidase Serine 2 (TMPRSS2), and Furin Expression Increases in the Lungs of Patients with Idiopathic Pulmonary Fibrosis (IPF) and Lymphangioleiomyomatosis (LAM): Implications for SARS-CoV-2 (COVID-19) Infections.

We previously reported higher ACE2 levels in smokers and patients with COPD. The current study investigates if patients with interstitial lung diseases (ILDs) such as IPF and LAM have elevated ACE2, TMPRSS2, and Furin levels, increasing their risk for SARS-CoV-2 infection and development of COVID-19. Surgically resected lung tissue from IPF, LAM patients, and healthy controls (HC) was immunostained for ACE2, TMPRSS2, and Furin. Percentage ACE2, TMPRSS2, and Furin expression was measured in small airway epithelium (SAE) and alveolar areas using computer-assisted Image-Pro Plus 7.0 software. IPF and LAM tissue was also immunostained for myofibroblast marker α-smooth muscle actin (α-SMA) and growth factor transforming growth factor beta1 (TGF-ß1). Compared to HC, ACE2, TMPRSS2 and Furin expression were significantly upregulated in the SAE of IPF (p < 0.01) and LAM (p < 0.001) patients, and in the alveolar areas of IPF (p < 0.001) and LAM (p < 0.01). There was a significant positive correlation between smoking history and ACE2 expression in the IPF cohort for SAE (r = 0.812, p < 0.05) and alveolar areas (r = 0.941, p < 0.01). This, to our knowledge, is the first study to compare ACE2, TMPRSS2, and Furin expression in patients with IPF and LAM compared to HC. Descriptive images show that α-SMA and TGF-ß1 increase in the IPF and LAM tissue. Our data suggests that patients with ILDs are at a higher risk of developing severe COVID-19 infection and post-COVID-19 interstitial pulmonary fibrosis. Growth factors secreted by the myofibroblasts, and surrounding tissue could further affect COVID-19 adhesion proteins/cofactors and post-COVID-19 interstitial pulmonary fibrosis. Smoking seems to be the major driving factor in patients with IPF.

Smoking Upregulates Angiotensin-Converting Enzyme-2 Receptor: A Potential Adhesion Site for Novel Coronavirus SARS-CoV-2 (Covid-19).

The epicenter of the original outbreak in China has high male smoking rates of around 50%, and early reported death rates have an emphasis on older males, therefore the likelihood of smokers being overrepresented in fatalities is high. In Iran, China, Italy, and South Korea, female smoking rates are much lower than males. Fewer females have contracted the virus. If this analysis is correct, then Indonesia would be expected to begin experiencing high rates of Covid-19 because its male smoking rate is over 60% (Tobacco Atlas). Smokers are vulnerable to respiratory viruses. Smoking can upregulate angiotensin-converting enzyme-2 (ACE2) receptor, the known receptor for both the severe acute respiratory syndrome (SARS)-coronavirus (SARS-CoV) and the human respiratory coronavirus NL638. This could also be true for new electronic smoking devices such as electronic cigarettes and "heat-not-burn" IQOS devices. ACE2 could be a novel adhesion molecule for SARS-CoV-2 causing Covid-19 and a potential therapeutic target for the prevention of fatal microbial infections, and therefore it should be fast tracked and prioritized for research and investigation. Data on smoking status should be collected on all identified cases of Covid-19.