Unveiling the Cutting-Edge Impact of Polarized Macrophage-Derived Extracellular Vesicles and MiRNA Signatures on TGF-ß Regulation within Lung Fibroblasts.

Depending on local cues, macrophages can polarize into classically activated (M1) or alternatively activated (M2) phenotypes. This study investigates the impact of polarized macrophage-derived Extracellular Vesicles (EVs) (M1 and M2) and their cargo of miRNA-19a-3p and miRNA-425-5p on TGF-ß production in lung fibroblasts. EVs were isolated from supernatants of M0, M1, and M2 macrophages and quantified using nanoscale flow cytometry prior to fibroblast stimulation. The concentration of TGF-ß in fibroblast supernatants was measured using ELISA assays. The expression levels of miRNA-19a-3p and miRNA-425-5p were assessed via TaqMan-qPCR. TGF-ß production after stimulation with M0-derived EVs and with M1-derived EVs increased significantly compared to untreated fibroblasts. miRNA-425-5p, but not miRNA-19a-3p, was significantly upregulated in M2-derived EVs compared to M0- and M1-derived EVs. This study demonstrates that EVs derived from both M0 and M1 polarized macrophages induce the production of TGF-ß in fibroblasts, with potential regulation by miRNA-425-5p.

Extracellular Vesicles (EVs) as Crucial Mediators of Cell-Cell Interaction in Asthma.

Asthma is the most common chronic respiratory disorder worldwide and accounts for a huge health and economic burden. Its incidence is rapidly increasing but, in parallel, novel personalized approaches have emerged. Indeed, the improved knowledge of cells and molecules mediating asthma pathogenesis has led to the development of targeted therapies that significantly increased our ability to treat asthma patients, especially in severe stages of disease. In such complex scenarios, extracellular vesicles (EVs i.e., anucleated particles transporting nucleic acids, cytokines, and lipids) have gained the spotlight, being considered key sensors and mediators of the mechanisms controlling cell-to-cell interplay. We will herein first revise the existing evidence, mainly by mechanistic studies in vitro and in animal models, that EV content and release is strongly influenced by the specific triggers of asthma. Current studies indicate that EVs are released by potentially all cell subtypes in the asthmatic airways, particularly by bronchial epithelial cells (with different cargoes in the apical and basolateral side) and inflammatory cells. Such studies largely suggest a pro-inflammatory and pro-remodelling role of EVs, whereas a minority of reports indicate protective effects, particularly by mesenchymal cells. The co-existence of several confounding factors-including technical pitfalls and host and environmental confounders-is still a major challenge in human studies. Technical standardization in isolating EVs from different body fluids and careful selection of patients will provide the basis for obtaining reliable results and extend their application as effective biomarkers in asthma.

Low-Blood Lymphocyte Number and Lymphocyte Decline as Key Factors in COPD Outcomes: A Longitudinal Cohort Study.

BACKGROUND: Smokers with and without chronic obstructive pulmonary disease (COPD) are at risk of severe outcomes like exacerbations, cancer, respiratory failure, and decreased survival. The mechanisms for these outcomes are unclear; however, there is evidence that blood lymphocytes (BL) number might play a role. OBJECTIVE: The objective of this study is to investigate the relationship between BL and their possible decline over time with long-term outcomes in smokers with and without COPD. METHODS: In 511 smokers, 302 with COPD (COPD) and 209 without COPD (noCOPD), followed long term, we investigated whether BL number and BL decline over time might be associated with long-term outcomes. Smokers were divided according to BL number in high-BL (≥1,800 cells/µL) and low-BL (<1,800 cells/µL). Clinical features, cancer incidence, and mortality were recorded during follow-up. BL count in multiple samples and BL decline over time were calculated and related to outcomes. RESULTS: BL count was lower in COPD (1,880 cells/µL) than noCOPD (2,300 cells/µL; p < 0.001). 43% of COPD and 23% of noCOPD had low-BL count (p < 0.001). BL decline over time was higher in COPD than noCOPD (p = 0.040). 22.5% of the whole cohort developed cancer which incidence was higher in low-BL subjects and in BL decliners than high-BL (31 vs. 18%; p = 0.001) and no decliners (32 vs. 19%; p = 0.002). 26% in the cohort died during follow-up. Furthermore, low-BL count, BL decline, and age were independent risk factors for mortality by Cox regression analysis. CONCLUSION: BL count and BL decline are related to worse outcomes in smokers with and without COPD, which suggests that BL count and decline might play a mechanistic role in outcomes deterioration. Insights into mechanisms inducing the fall in BL count could improve the understanding of COPD pathogenesis and point toward new therapeutic measures.

Critical Review of the Evolution of Extracellular Vesicles' Knowledge: From 1946 to Today.

Extracellular vesicles (EVs) are a family of particles/vesicles present in blood and body fluids, composed of phospholipid bilayers that carry a variety of molecules that can mediate cell communication, modulating crucial cell processes such as homeostasis, induction/dampening of inflammation, and promotion of repair. Their existence, initially suspected in 1946 and confirmed in 1967, spurred a sharp increase in the number of scientific publications. Paradoxically, the increasing interest for EV content and function progressively reduced the relevance for a precise nomenclature in classifying EVs, therefore leading to a confusing scientific production. The aim of this review was to analyze the evolution of the progress in the knowledge and definition of EVs over the years, with an overview of the methodologies used for the identification of the vesicles, their cell of origin, and the detection of their cargo. The MISEV 2018 guidelines for the proper recognition nomenclature and ways to study EVs are summarized. The review finishes with a "more questions than answers" chapter, in which some of the problems we still face to fully understand the EV function and potential as a diagnostic and therapeutic tool are analyzed.

Clinical and Pathologic Factors Predicting Future Asthma in Wheezing Children. A Longitudinal Study.

Wheeze is a common symptom in infants, but not all wheezers develop asthma. Indeed, up to 50% of wheezing children outgrow their symptoms by school age. How to predict if early wheeze will become asthma is still a matter of vivid debate. In this work, we sought to assess the clinical and pathological factors that might predict the future development of asthma in children. Eighty children (mean age 3.8 ± 1 yr) who underwent a clinically indicated bronchoscopy were followed prospectively for a median of 5 years. At baseline, clinical characteristics with a particular focus on wheezing and its presentation (episodic or multitrigger) were collected, and structural and inflammatory changes were quantified in bronchial biopsies. Follow-up data were available for 74 of the 80 children. Children who presented with multitrigger wheeze were more likely to have asthma at follow-up than those with episodic wheeze (P = 0.04) or without wheeze (P < 0.0001). Children with asthma also had lower birth weights (P = 0.02), a lower prevalence of breastfeeding (P = 0.02), and a trend for increased IgE (P = 0.07) at baseline than those with no asthma. Basement membrane thickness and airway eosinophils at baseline were increased in children who developed asthma at follow-up (P = 0.001 and P = 0.026, respectively). Multivariate analysis showed that among all clinical and pathological factors, multitrigger wheezing, basement membrane thickening, and reduced birth weight were predictive of future asthma development. We conclude that multitrigger wheeze and reduced birth weight are clinical predictors of asthma development. Basement membrane thickening in early childhood is closely associated with asthma development, highlighting the importance of airway remodeling in early life as a risk factor for future asthma.

Dual polarization of human alveolar macrophages progressively increases with smoking and COPD severity.

BACKGROUND: It is known that tissue macrophages derive not only from blood monocytes but also from yolk sac or fetal liver, and the tissue of residence guides their function. When isolated, they lose tissue specific signatures, hence studies of human macrophages should be ideally done directly in the tissue. The aim of this study was to investigate directly in human lung tissue the polarization of alveolar macrophage (AM), classic (M1) or alternative (M2), in health and disease, using COPD as a model. METHODS: Surgical lungs from 53 subjects were studied: 36 smokers whose FEV1 varied from normal to severe COPD, 11 non-smokers and 6 normal donors. iNOS and CD206 immunohistochemistry was used to quantify the percentage of AM polarized as M1 or M2 in lung sections. RESULTS AND DISCUSSION: The percentage of M1 and M2 increased progressively with smoking and COPD severity, from 26% to 84% for M1 and from 7% to 78% for M2. In donors 74% of AM were negative for M1 and 93% for M2. Confocal microscopy showed co-localization of M1 and M2 in the same AM in severe COPD. CONCLUSION: In normal lungs alveolar macrophages were mostly non-polarized. With smoking and COPD severity, M1 and M2 polarization increased significantly and so did the co-expression of M1 and M2 in the same alveolar macrophage.

Alpha-1 Antitrypsin Deficiency Today: New Insights in the Immunological Pathways.

More than 50 years ago, the observation that absence of the α1 band from protein electrophoresis is associated with severe emphysema established the link between α1-antitrypsin deficiency (AATD) and lung damage. From this discovery, the classic paradigm of protease/antiprotease imbalance was derived, linking lung destruction in patients with AATD to the unopposed effect of proteases. By extension, this paradigm was also applied to patients with 'common' chronic obstructive pulmonary disease, in whom large increases in smoke-induced proteases could overwhelm the antiprotease capability of AAT. However, it has become increasingly evident that AAT has important anti-inflammatory and immunoregulatory activities which, beside its antiprotease function, may be critically involved in lung destruction. From this perspective, we will consider recent evidence, based on epidemiological, clinical and immunopathological studies, suggesting that it is time to move on from the original protease/antiprotease paradigm toward a more complex view of the condition, which embraces its immunomodulating functions. Of importance, the potent immunoregulatory, tolerogenic role of AAT may support its therapeutic use in a number of diseases other than AATD, particularly in immune-related disorders.

Immune activation in α1-antitrypsin-deficiency emphysema. Beyond the protease-antiprotease paradigm.

RATIONALE: α1-Antitrypsin (AAT) is a potent protease inhibitor, deficiency of which is associated with the presence of emphysema. An imbalance of elastase and antielastase, along with innate inflammation in the lung, is believed to cause lung destruction in α1-antitrypsin deficiency (AATD). It is now apparent that AAT has important immune-regulatory roles that would be lost in AATD, yet adaptive immune responses in the lung have not been investigated in patients with AATD. OBJECTIVES: To assess the adaptive immune response in severe AATD emphysema and compare it with that present in "usual" chronic obstructive pulmonary disease (COPD). METHODS: The immune inflammatory response in explanted lungs from 10 subjects with AATD was characterized and quantified, and the results were compared with those of 26 subjects with usual COPD and those of 17 smoking and 11 nonsmoking control subjects with normal lung function. MEASUREMENTS AND MAIN RESULTS: Lymphoid follicles (LFs) in AATD and usual COPD were markedly increased when compared with control groups. Molecular analysis of B lymphocytes in LFs showed predominantly mono/oligoclonality. LF number correlated negatively with FEV1/FVC. B lymphocytes and CD4(+) and CD8(+) T lymphocytes were significantly increased in AATD and usual COPD when compared with control groups. IL-32, an important cytokine in induction of autoimmunity, was markedly up-regulated in AATD and usual COPD. CONCLUSIONS: An important adaptive immune inflammation, comprising B, CD4(+), and CD8(+) lymphocytes, and LFs, is a prominent feature in AATD. These results change the paradigm of the mechanism of AATD-induced emphysema from a pure elastase-antielastase imbalance to a much more complex one involving the adaptive immune system, similarly to what occurs in usual COPD.

Suppressor of cytokine signaling-3 expression and its regulation in relation to inflammation in Chronic Obstructive Pulmonary Disease.

Background: The family of Suppressor of Cytokine Signaling (SOCS) acts as a controller of the duration and intensity of cytokine function by negatively regulating the JAK-STAT signaling pathway. SOCS' role in inflammatory diseases in animal models is well demonstrated. However, its role in the development of human disease is still under investigation. SOCS3 plays an important role in tumor development where its downregulation has been implicated in the pathogenesis of various solid tumors such as triple-negative breast cancer. Aim: The aim of this work was to study (1) the expression of SOCS3 in smokers' lungs and its relation to the degree of inflammation and (2) SOCS3 regulation by microRNA (miRNA) in alveolar-macrophage (AM)-derived extracellular vesicles (EVs) in bronchoalveolar lavage (BAL). Methods: Group A: 35 smokers' [19 with COPD (SC) and 16 without COPD (S)] and 9 nonsmokers (NS); SOCS3, TNFα in AM, and CD8+ T cells were quantified by immunohistochemistry, in lung tissue. Group B: additional 9 SC, 11 S, and 5 NS; AM-EVs expressing SOCS3 (CD14+SOCS3+) and SOCS3 suppressors miRNA-19a-3p and 221-3p in EVs were quantified by flow cytometry and PCR, in BAL. Results: The percentage of SOCS3+ AM was higher in SC [68 (6.6-99)%] and S [48 (8-100)%] than in NS [9.6 (1.9-61)%; p = 0.002; p = 0.03] and correlated with % of TNFα+AM (r = 0.48; p = 0.0009) and CD8+ T cells (r = 0.44; p = 0.0029). In BAL, the CD14+SOCS3+ EVs/µL were increased in SC [33 (21-74)] compared to S [16 (8-37); p = 0.03] and NS [9 (7-21); p = 0.003]. Conversely, miRNA-19a-3p and miRNA-221-3p expression were increased in S when compared to SC [19 (2-53) vs. 3 (0.6-8); p = 0.03 and 3 (0.005-9.6) vs. 0.2 (0.08-0.7); p = 0.05]. Conclusions: The suppressor function of SOCS3 in COPD seems to be overridden by other factors and does not follow the animal-model paradigm. Expression of SOCS3 in BAL macrophage-derived EVs might be useful to assess the degree of inflammation and possible progression of COPD. Downregulation of SOCS3, by miRNA, in smokers without COPD might contribute to the risk of developing cancer in these patients.

Ceramide expression and cell homeostasis in chronic obstructive pulmonary disease.

BACKGROUND: Increased expression of ceramide has been detected in emphysema. Ceramide promotes autophagy and apoptosis, which concur with cellular homeostasis. OBJECTIVES: To determine whether ceramide expression is associated with the development of chronic obstructive pulmonary disease (COPD) and with altered cellular homeostasis in lung parenchyma. METHODS: We studied 10 subjects with severe COPD, 13 with mild/moderate COPD, 11 with idiopathic pulmonary fibrosis (IPF), 12 non-COPD smokers, and 11 nonsmoking controls. The immunoreactivity for ceramide along with markers of autophagy (LC3B), apoptosis (cleaved caspase-3), and cell proliferation (MIB1) was quantified in alveolar walls. RESULTS: Ceramide expression was increased in COPD patients compared with control smokers and was related to the impairment of gas exchange but not to the degree of airflow limitation. In COPD, an important activation of apoptosis and autophagy pathways was observed, particularly in patients with severe disease, that was not counterbalanced by cell proliferation. Upregulation of ceramide was observed even in subjects with IPF in whom activation of apoptosis and autophagy was negligible and cell proliferation was instead the most prominent feature. CONCLUSIONS: Ceramide expression, which is increased in COPD and even more so in IPF, appears to be neither specific nor related to COPD severity, probably representing a broader marker of lung damage. In contrast, apoptosis and autophagy are characteristics of the COPD pathology, particularly in its most severe stage.

Mast cell infiltration discriminates between histopathological phenotypes of chronic obstructive pulmonary disease.

RATIONALE: COPD is a complex disease with heterogeneous manifestations. Attempts have been made to define different phenotypes that could guide toward better disease understanding. We described before that smokers can develop either panlobular (PLE) or centrilobular emphysema (CLE). The latter has worse small airways remodeling and narrowing, which account for the airflow obstruction similar to asthma. OBJECTIVES: Because of the small airways involvement in CLE similar to asthma, we hypothesized a role for mast cells in CLE but not in PLE. Hence, we investigated mast cell infiltration, along with overall inflammation, and their relation with hyperreactivity and emphysema type in COPD. METHODS: We studied lung function, emphysema type, mast cells, and overall inflammation in small airways and alveolar walls, along with alveolar wall thickening in 67 subjects undergoing lung resection (59 smokers, 8 nonsmokers). MEASUREMENTS AND MAIN RESULTS: Twenty-seven smokers had CLE, 24 had PLE, and 8 had no emphysema. Mast cells were significantly increased in CLE compared with PLE and control subjects. Especially relevant was the mast cell increase in airway smooth muscle in CLE, which related significantly to airway hyperreactivity. CD4(+)T cells, neutrophils, and macrophages, but not eosinophils and CD8(+)T cells, were significantly higher in CLE than PLE. Alveolar wall thickness was increased in all smokers, but significantly more in CLE. CONCLUSIONS: The pathological phenotypes of COPD CLE and PLE show important differences in their overall inflammation with a protagonism of mast cells, which are related to airway reactivity. These findings highlight the distinctness of these COPD phenotypes and the role of mast cells in the pathophysiology of COPD.

Deficient antiviral immune responses in childhood: distinct roles of atopy and asthma.

BACKGROUND: Impaired immune response to viral infections in atopic asthmatic patients has been recently reported and debated. Whether this condition is present in childhood and whether it is affected by atopy per se deserves further investigation. OBJECTIVE: We sought to investigate airway interferon production in response to rhinovirus infection in children who are asthmatic, atopic, or both and its correlation with the airway inflammatory profile. METHODS: Bronchial biopsy specimens and epithelial cells were obtained from 47 children (mean age, 5 ± 0.5 years) undergoing bronchoscopy. The study population included asthmatic children who were either atopic or nonatopic, atopic children without asthma, and children without atopy or asthma. Rhinovirus type 16 induction of IFN-λ and IFN-ß mRNA and protein levels was assessed in bronchial epithelial cell cultures. The immunoinflammatory profile was evaluated by means of immunohistochemistry in bronchial biopsy specimens. RESULTS: Rhinovirus type 16-induced interferon production was significantly reduced in atopic asthmatic, nonatopic asthmatic, and atopic nonasthmatic children compared with that seen in nonatopic nonasthmatic children (all P < .05). Increased rhinovirus viral RNA levels paralleled this deficient interferon induction. Additionally, IFN-λ and IFN-ß induction correlated inversely with the airway T(H)2 immunopathologic profile (eosinophilia and IL-4 positivity: P < .05 and r = -0.38 and P < .05 and r = -0.58, respectively) and with epithelial damage (P < .05 and r = -0.55). Furthermore, total serum IgE levels correlated negatively with rhinovirus-induced IFN-λ mRNA levels (P < .05 and r = -0.41) and positively with rhinovirus viral RNA levels (P < .05 and r = 0.44). CONCLUSIONS: Deficient interferon responses to rhinovirus infection are present in childhood in asthmatic subjects irrespective of their atopic status and in atopic patients without asthma. These findings suggest that deficient immune responses to viral infections are not limited to patients with atopic asthma but are present in those with other T(H)2-oriented conditions.

Extracellular Vesicles in Lung Cancer: Bystanders or Main Characters?

Lung cancer still represents the main cause of cancer death worldwide. The poor survival is mainly related to the diagnosis which is often obtained in advanced stages when the disease is unresectable and characterized by the worst prognosis. Only in the last decades have great discoveries led to the development of new therapies targeted to oncogenes and to boost the host immune response against the tumor. Tumor identification and molecular/immunological characterization rely on bioptic samples which represent the gold standard for diagnosis. Nonetheless, less invasive procedures providing small samples will be more and more common in the future. Extracellular vesicles (EV), submicron particles released by any cell type, are candidates for diagnostic and prognostic biomarkers. EV are mediators of intercellular communication and can convey cytokines, miRNAs, antigens, and many other factors of tumorigenesis. This review summarizes the most appealing findings on lung-cancer-related EV, debating the evidence on circulating versus airway EV as potential biomarkers in disease management and the main studies on the role of these particles on lung cancer pathogenesis. Overall, the available results point toward a wide range of possible applications, supported by the promising achievements of genotyping on BAL fluid EV and proteomic analysis on pleural effusion EV. Nonetheless, the study of lung EV is still affected by remarkable methodological issues, especially when in vitro evidence is translated into humans. Whether EV still represent an "information fog" or can be useful in lung cancer management will be discussed, with possible hints on how to improve their usage.

Clinical Applications of Endobronchial Ultrasound (EBUS) Scope: Challenges and Opportunities.

Endobronchial Ultrasound (EBUS) has been widely used to stage lung tumors and to diagnose mediastinal diseases. In the last decade, this procedure has evolved in several technical aspects, with new tools available to optimize tissue sampling and to increase its diagnostic yield, like elastography, different types of needles and, most recently, miniforceps and cryobiopsy. Accordingly, the indications for the use of the EBUS scope into the airways to perform the Endobronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) has also extended beyond the endobronchial and thoracic boundaries to sample lesions from the liver, left adrenal gland and retroperitoneal lymph nodes via the gastroesophageal tract, performing the Endoscopic UltraSound with Bronchoscope-guided Fine Needle Aspiration (EUS-B-FNA). In this review, we summarize and critically discuss the main indication for the use of the EBUS scope, even the more uncommon, to underline its utility and versatility in clinical practice.

Macrophages-derived Factor XIII links coagulation to inflammation in COPD.

Background: The local, extravascular, activation of the coagulation system in response to injury is a key factor mediating the resulting inflammatory response. Coagulation Factor XIIIA (FXIIIA) found in alveolar macrophages (AM) and dendritic cells (DC), by influencing fibrin stability, might be an inflammatory modifier in COPD. Aims: To study the expression of FXIIIA in AM and Langerin+DC (DC-1) and their relation to the inflammatory response and disease progression in COPD. Methods: In 47 surgical lungs, 36 from smokers (22 COPD and 14 no-COPD) and 11 from non-smokers we quantified by immunohistochemistry FXIIIA expression in AM and DC-1 along with numbers of CD8+Tcells and CXCR3 expression in lung parenchyma and airways. Lung function was measured prior to surgery. Results: The percentage of AM expressing FXIII (%FXIII+AM) was higher in COPD than no-COPD and non-smokers. DC-1 expressed FXIIIA and their numbers were higher in COPD than no-COPD and non-smokers. DC-1 positively correlated with %FXIII+AM (r=0.43; p<0.018). CD8+Tcells, which were higher in COPD than in no-COPD, were correlated with DC-1 (p<0.01) and %FXIII+AM. CXCR3+ cells were increased in COPD and correlated with %FXIII+AM (p<0.05). Both %FXIII+AM (r=-0.6; p=0.001) and DC-1 (r=-0.7; p=0.001) correlated inversely with FEV1. Conclusion: FXIIIA, an important link between the extravascular coagulation cascade and inflammatory response, is significantly expressed in alveolar macrophages and dendritic cells of smokers with COPD, suggesting that it could play an important role in the adaptive inflammatory reaction characteristic of the disease.

Pathophysiology of the small airways in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterized by a persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases. From a pathological point of view, COPD is characterized by two distinct and frequently coexisting aspects: small airway abnormalities and parenchymal destruction (or emphysema). When pathological changes are localized in lung parenchyma, they will contribute to airflow limitation by reducing the elastic recoil of the lung through parenchymal destruction, as well as by reducing the elastic load applied to the airways through destruction of alveolar attachments. Conversely, when pathological changes involve the small airways, they will contribute to airflow limitation by narrowing and obliterating the lumen and by actively constricting the airways, therefore increasing the resistance. In this article we will review the structural abnormalities in small airways and their relationship with the disordered pulmonary function in COPD, in the attempt to disentangle the mechanisms contributing to the development and progression of airflow limitation in smokers. We will start by describing the normal structure of the small airways, and then observe the main pathological alterations that accumulate in this site and how they parallel pulmonary function derangement.

Symptomatic smokers without COPD have physiological changes heralding the development of COPD.

Background: COPD is a major health problem, mainly due to cigarette smoking. Most studies in COPD are dedicated to fully developed COPD in older subjects, even though development of COPD may start soon after smoking initiation. Therefore, there is a need to diagnose this "early disease" by detecting the initial events responsible for ultimate development of COPD. Methods: Measurement of maximum mid expiratory flow between 25 and 75% of vital capacity (MMEF) in a routine spirometry, which detects small airways disease, was used to investigate if MMEF abnormalities in smokers without COPD (noCOPD) would relate to respiratory symptoms and identify smokers that might progress to COPD. For this purpose we studied 511 smokers, 302 COPD and 209 noCOPD, followed long term with spirometry including MMEF, diffusing capacity of the lung for carbon monoxide (D LCO), 6-min walk test (6MWT), Medical Research Council Dyspnoea Scale and COPD Assessment Test. Three spirometries V1,V2 and V3 (5±2.5 and 10±4 years apart from V1) were performed to assess functional decline and development of COPD. Results: 65% of noCOPD had an abnormal MMEF (<80%) and 38% an abnormal D LCO. The NoCOPD with MMEF <80% group performed worse in the 6MWT (p=0.01), was more dyspnoeic (p=0.01) and had higher prevalence of chronic bronchitis than the noCOPD with MMEF>80% group (p=0.04). 21% of noCOPD with MMEF <80% and 2.7% with MMEF>80% developed COPD by V3 (p=0.0004). Conclusions: The MMEF, a functional test available in a routine spirometry, can detect early lung abnormalities and identify the subset of symptomatic smokers with pathological changes that might lead to COPD.