Cigarette smoking promotes inflammation in patients with COPD by affecting the polarization and survival of Th/Tregs through up-regulation of muscarinic receptor 3 and 5 expression

Association between serum cotinine concentrations on red blood cell folate concentrations in pregnant women and the mediating role of lymphocytes: an NHANES Study

BACKGROUND

Folate is essential for DNA synthesis and cell division, particularly during pregnancy, where insufficient levels can lead to adverse outcomes like neural tube defects and preterm birth. Tobacco smoke exposure, indicated by serum cotinine levels, is a known risk factor for reduced folate levels. However, the mechanisms underlying this relationship, especially the role of lymphocytes, are not well understood.

OBJECTIVES

This study evaluates the relationship between serum cotinine levels and RBC folate concentrations in pregnant women, explores the mediating role of lymphocyte count, and identifies susceptibility factors that could guide targeted interventions.

METHODS

We conducted a cross-sectional analysis using NHANES data from 1999 to 2018, including 1,021 pregnant women. Serum cotinine levels were used as a biomarker for tobacco exposure, while RBC folate levels indicated long-term folate status. Linear regression, restricted cubic spline, and mediation analyses were performed to assess these relationships.

RESULTS

Serum cotinine levels were significantly negatively correlated with RBC folate concentrations (P < 0.001). A nonlinear relationship revealed more pronounced folate depletion at higher cotinine levels. Mediation analysis showed that elevated lymphocyte count mediated 19.3% of the cotinine-folate association. Factors such as smoking history, advanced maternal age, and heavy alcohol consumption exacerbated this negative effect.

CONCLUSION

Tobacco exposure(as reflected by elevated cotinine levels) significantly reduces folate levels in pregnant women, with lymphocyte count playing a mediating role. These findings underscore the need for targeted public health interventions to mitigate tobacco-related risks during pregnancy.

Differential proteins from EVs identification based on tandem mass tags analysis and effect of Treg-derived EVs on T-lymphocytes in COPD patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a widespread respiratory disease. This study examines extracellular vesicles (EVs) and proteins contained in EVs in COPD.

METHODS

Blood samples were collected from 40 COPD patients and 10 health controls. Cytokines including IFN-γ, TNF-α, IL-1β, IL-6, IL-8, and IL-17, were measured by ELISA. Small EVs samples were extracted from plasma and identified by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), and Western blot. Protein components contained in EVs were analyzed by Tandem Mass Tags (TMT) to identify differential proteins. Treg-derived EV was extracted and added to isolated CD8+, Treg, and Th17 subsets to assess its effect on T-lymphocytes.

RESULTS

ELISA revealed higher levels of all cytokines and flow cytometry suggested a higher proportion of Treg and Th17 cells in COPD patients. After identification, TMT analysis identified 207 unique protein components, including five potential COPD biomarkers: BTRC, TRIM28, CD209, NCOA3, and SSR3. Flow cytometry revealed that Treg-derived EVs inhibited differentiation into CD8+, CD4+, and Th17 cells.

CONCLUSION

The study shows that cytokines, T-lymphocyte subsets differences in COPD and Treg-derived EVs influence T-lymphocyte differentiation. Identified biomarkers may assist in understanding COPD pathogenesis, prognosis, and therapy. The study contributes to COPD biomarker research.

Cigarette Smoking Contributes to Th1/Th2 Cell Dysfunction via the Cytokine Milieu in Chronic Obstructive Pulmonary Disease

Background

Dysregulation and pyroptosis of T-helper (Th) cells and inflammatory cytokines have been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the immune response mechanisms as a consequence of tobacco smoke exposure are not fully understood. We hypothesized that cigarette smoke-induced inflammation could be modulated through the cytokine milieu and T-cell nicotinic acetylcholine receptors (nAChRs).

Methods

The proportions of peripheral blood Th1 and Th2 cells from patients with COPD, smokers without airway obstruction and healthy nonsmokers were analyzed using flow cytometry. The levels of plasma proinflammatory cytokines and their potential association with pulmonary function were also measured. The influence of cigarette smoke extract (CSE) on the conditioned differentiation of T helper cell subsets was further examined in vitro.

Results

Significantly higher Th1 cell and plasma IFN-γ and IL-18 levels but lower levels of Th2 cells were found in the peripheral blood from patients with COPD. The increased plasma levels of IFN-γ and IL-18 were negatively correlated with pulmonary function (FEV1% predicted value). Pyroptosis participates in COPD development probably through the activation of the NLRP3 inflammasome upon exposure to CSE. CSE does not directly induce the differentiation of T helper cells; however, under conditioned medium, CSE promotes Th1 development through α7 nAChR modification, while it does not substantially interfere with Th2 differentiation.

Conclusion

The differences in the cytokine milieu play a key role in the effects of CSE on the immune response in patients with COPD.

Decreased programmed cell death ligand 2-positive monocytic myeloid-derived suppressor cells and programmed cell death protein 1-positive T-regulatory cells in patients with type 2 diabetes: implications for immunopathogenesis

Objectives

The activation of immune cells plays a significant role in the progression of type 2 diabetes. This study aimed to investigate the potential role of myeloid-derived suppressor cells (MDSCs) and T-regulatory cells (Tregs) in type 2 diabetes.

Methods

A total of 61 patients diagnosed with type 2 diabetes were recruited. Clinical characteristics were reviewed and peripheral blood samples were collected. We calculated the percentage of different cells. Frequencies of MDSC subsets refered to the percentage of G-MDSCs (CD15+CD33+CD11b+CD14-HLA-DR-/low) in CD45 positive cells and the percentage of M-MDSCs (CD14+CD15-CD11b+CD33+HLA-DR-/low) in lymphocytes plus monocytes.

Results

Frequencies of programmed cell death ligand 1-positive granulocytic MDSCs (PD-L1+ G-MDSCs), programmed cell death ligand 2-positive monocytic MDSCs (PD-L2+ M-MDSCs), PD-L2+ G-MDSC, and programmed cell death protein 1-positive Tregs (PD-1+Tregs) were decreased in patients with type 2 diabetes. The frequency of PD-1+ Tregs was positively related to PD-L2+ M-MDSCs (r= 0.357, P = 0.009) and negatively related to HbA1c (r = -0.265, P = 0.042), fasting insulin level (r = -0.260, P = 0.047), and waist circumference (r = -0.373, P = 0.005).

Conclusions

Decreased PD-L2+ M-MDSCs and PD-1+ Tregs may promote effector T cell activation, leading to chronic low-grade inflammation in type 2 diabetes. These findings highlight the contribution of MDSCs and Tregs to the immunopathogenesis of type 2 diabetes and suggest their potential as targets for new therapeutic approaches.

Immunological Insights into Cigarette Smoking-Induced Cardiovascular Disease Risk

Smoking is one of the most prominent addictions of the modern world, and one of the leading preventable causes of death worldwide. Although the number of tobacco smokers is believed to be at a historic low, electronic cigarette use has been on a dramatic rise over the past decades. Used as a replacement for cigarette smoking, electronic cigarettes were thought to reduce the negative effects of burning tobacco. Nonetheless, the delivery of nicotine by electronic cigarettes, the most prominent component of cigarette smoke (CS) is still delivering the same negative outcomes, albeit to a lesser extent than CS. Smoking has been shown to affect both the structural and functional aspects of major organs, including the lungs and vasculature. Although the deleterious effects of smoking on these organs individually is well-known, it is likely that the adverse effects of smoking on these organs will have long-lasting effects on the cardiovascular system. In addition, smoking has been shown to play an independent role in the homeostasis of the immune system, leading to major sequela. Both the adaptive and the innate immune system have been explored regarding CS and have been demonstrated to be altered in a way that promotes inflammatory signals, leading to an increase in autoimmune diseases, inflammatory diseases, and cancer. Although the mechanism of action of CS has not been fully understood, disease pathways have been explored in both branches of the immune system. The pathophysiologically altered immune system during smoking and its correlation with cardiovascular diseases is not fully understood. Here we highlight some of the important pathological mechanisms that involve cigarette smoking and its many components on cardiovascular disease and the immune systems in order to have a better understanding of the mechanisms at play.

Inducible Costimulator-C-X-C Motif Chemokine Receptor 3 Signaling is Involved in Chronic Obstructive Pulmonary Disease Pathogenesis

Background

The role of inducible costimulator (ICOS) signaling in chronic obstructive pulmonary disease (COPD) has not been fully elucidated.

Methods

We compared the percentages of ICOS⁺ T cells and ICOS⁺ regulatory T (Treg) cells in CD4⁺ T cells and CD4⁺CD25⁺FOXP3⁺ Tregs, respectively, in the peripheral blood of smokers with or without COPD to those in healthy controls. We further characterized their phenotypes using flow cytometry. To investigate the influence of ICOS signaling on C-X-C motif chemokine receptor 3 (CXCR3) expression in COPD, we evaluated the expression levels of ICOS and CXCR3 in vivo and in vitro.

Results

ICOS expression was elevated on peripheral CD4⁺ T cells and CD4⁺ Tregs of COPD patients, which positively correlated with the severity of lung function impairment in patients with stable COPD (SCOPD), but not in patients with acute exacerbation of COPD (AECOPD). ICOS⁺CD4⁺ Tregs in patients with SCOPD expressed higher levels of coinhibitors, programmed cell death protein 1 (PD-1) and T-cell immunoreceptor with Ig and ITIM domains (TIGIT), than ICOS⁻CD4⁺ Tregs, whereas ICOS⁺CD4⁺ T cells mostly exhibited a central memory (CD45RA⁻CCR7⁺) or effector memory (CD45RA⁻CCR7⁻) phenotype, ensuring their superior potential to respond potently and quickly to pathogen invasion. Furthermore, increased percentages of CXCR3⁺CD4⁺ T cells and CXCR3⁺CD4⁺ Tregs were observed in the peripheral blood of patients with SCOPD, and the expression level of CXCR3 was higher in ICOS⁺CD4⁺ T cells than in ICOS⁻CD4⁺ T cells. The percentage of CXCR3⁺CD4⁺ T cells was even higher in the bronchoalveolar lavage fluid than in matched peripheral blood in SCOPD group. Lastly, in vitro experiments showed that ICOS induced CXCR3 expression on CD4⁺ T cells.

Conclusions

ICOS signaling is upregulated in COPD, which induces CXCR3 expression. This may contribute to increased numbers of CXCR3⁺ Th1 cells in the lungs of patients with COPD, causing inflammation and tissue damage.

The mechanistic role of neutrophil lymphocyte ratio perturbations in the leading non communicable lifestyle diseases

Inflammation plays a critical role in the development and progression of chronic diseases like type 2 diabetes mellitus, coronary artery disease, and chronic obstructive pulmonary disease. Inflammatory responses are indispensable for pathogen control and tissue repair, but they also cause collateral damage. A chronically activated immune system and the resultant immune dysregulation mediated inflammatory surge may cause multiple negative effects, requiring tight regulation and dampening of the immune response to minimize host injury.  While chronic diseases are characterized by systemic inflammation, the mechanistic relationship of neutrophils and lymphocytes to inflammation and its correlation with the clinical outcomes is yet to be elucidated. The neutrophil to lymphocyte ratio (NLR) is an easy-to-measure laboratory marker used to assess systemic inflammation. Understanding the mechanisms of NLR perturbations in chronic diseases is crucial for risk stratification, early intervention, and finding novel therapeutic targets. We investigated the correlation between NLR and prevalent chronic conditions as a measure of systemic inflammation. In addition to predicting the risk of impending chronic conditions, NLR may also provide insight into their progression. This review summarizes the mechanisms of NLR perturbations at cellular and molecular levels, and the key inflammatory signaling pathways involved in the progression of chronic diseases. We have also explored preclinical studies investigating these pathways and the effect of quelling inflammation in chronic disease as reported by a few in vitro, in vivo studies, and clinical trials.

Implications of the Immune Landscape in COPD and Lung Cancer: Smoking Versus Other Causes

Cigarette smoking is reported in about one third of adults worldwide. A strong relationship between cigarette smoke exposure and chronic obstructive pulmonary disease (COPD) as well as lung cancer has been proven. However, about 15% of lung cancer cases, and between one fourth and one third of COPD cases, occur in never-smokers. The effects of cigarette smoke on the innate as well as the adaptive immune system have been widely investigated. It is assumed that certain immunologic features contribute to lung cancer and COPD development in the absence of smoking as the major risk factor. In this article, we review different immunological aspects of lung cancer and COPD with a special focus on non-smoking related risk factors.

Effects of Vitamin D on Respiratory Function and Immune Status for Patients with Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis

BACKGROUND

Many studies have demonstrated that vitamin D has clinical benefits when used to treat patients with chronic obstructive pulmonary disease (COPD). However, most of these studies have insufficient samples or inconsistent results. The aim of this meta-analysis was to evaluate the effects of vitamin D therapy in patients with COPD.

METHODS

We performed a comprehensive retrieval in the following electronic databases: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, and Chinese Scientific Journals Database (VIP). Two trained reviewers identified relevant studies, extracted data information, and then assessed the methodical quality by the Cochrane risk of bias assessment tool, independently. Then, the meta-analyses were conducted by RevMan 5.4, binary variables were represented by risks ratio (RR), and continuous variables were represented by mean difference (MD) or standardized mean difference (SMD) to assess the efficacy of vitamin D therapy in patients with COPD. Then, publication bias assessment was conducted by funnel plot analysis. Finally, the quality of evidence was assessed by the GRADE system.

RESULTS

A total of 15 articles involving 1598 participants were included in this study. The overall results showed a statistical significance of vitamin D therapy in patients with COPD which can significantly improve forced expiratory volume in 1 second (FEV1) (MD: 5.69, 95% CI: 5.01-6.38,P < 0.00001,I2 = 51%) and FEV1/FVC (SMD:0.49, 95% CI: 0.39-0.60,P < 0.00001,I2 = 84%); and serum 25 (OH)D (SMD:1.21, 95% CI:1.07-1.34,P < 0.00001,I2 = 98%) also increase CD3+ Tcells (MD: 6.67, 95% CI: 5.34-8.00,P < 0.00001,I2 = 78%) and CD4+ T cells (MD: 6.00, 95% CI: 5.01-7.00,P < 0.00001,I2 = 65%); and T lymphocyte CD4+/CD8+ ratio (MD: 0.41, 95% CI: 0.20-0.61,P = 0.0001,I2 = 95%) obviously decrease CD8+ Tcells(SMD: -0.83, 95% CI: -1.05- -0.06,P < 0.00001,I2 = 82%), the times of acute exacerbation (RR: 0.40, 95% CI: 0.28-0.59,P < 0.00001,I2 = 0%), and COPD assessment test (CAT) score (MD: -3.77, 95% CI: -5.86 - -1.68,P = 0.0004,I2 = 79%).

CONCLUSIONS

Our analysis indicated that vitamin D used in patients with COPD could improve the lung function (FEV1 and FEV1/FVC), the serum 25(OH)D, CD3+ T cells, CD4 + T cells, and T lymphocyte CD4+/CD8+ ratio and reduce CD8+ T cells, acute exacerbation, and CAT scores.

Efficacy of nalmefene with noninvasive positive-pressure ventilation on elderly patients with chronic obstructive pulmonary disease combining with type II respiratory failure

OBJECTIVE

To investigate the therapeutic effect of nalmefene combined with noninvasive positive-pressure mechanical ventilation (NIPPV) on elderly patients with chronic obstructive pulmonary disease (COPD) complicated with type II respiratory failure and to explore its influence on TGF-β1/Smads signaling pathway.

METHODS

In this retrospective study, data of 106 COPD patients with type II respiratory failure were collected and divided into a research group and a control group based on different treatment, with 53 cases in each group. Both groups were given NIPPV. Besides, the control group was treated with conventional therapy and the research group was treated with nalmefene for 7 days. The changes of heart rate, respiratory rate, clinical efficacy, pulmonary arterial pressure (PAP), serum inflammatory parameters, levels of TGF-β1/Smads signaling pathway related molecules and the incidences of adverse reactions of both groups were compared.

RESULTS

After treatment, the heart rate, respiratory rate, PAP, IL-6 and TNF-α concentrations in both groups were lower than those before treatment (P<0.05). The levels of PaO₂ and SaO₂ were higher and the levels of PaCO₂ were lower than those before treatment in both groups (P<0.05). The expression levels of TGF-β1 and Smad2 in the research group were significantly lower than those in the control group (P<0.05). And all the above indicators in the research group were better than those in the control group after treatment (P<0.05). Besides, the incidence of adverse reactions in the research group was lower than that in the control group (P<0.05).

CONCLUSION

Nalmefene combined with NIPPV can significantly improve the level of PaO₂ and reduce inflammatory response in elderly COPD patients with type II respiratory failure, and the mechanism may be related to the inhibition of TGF-β1 and Smads expressions.

N-Acetylcysteine Improves Inflammatory Response in COPD Patients by Regulating Th17/Treg Balance through Hypoxia Inducible Factor-1α Pathway

Introduction

This study was aimed to investigate the effects of N-acetylcysteine (NAC) on chronic obstructive pulmonary disease (COPD) and the change of Th17/Treg cytokine imbalance. Material and Methods. A total of 121 patients with stable COPD at the stage of C or D were consecutively enrolled and randomly divided into 2 groups. Patients in the treatment group received NAC granules (0.2 g × 10 bags, 0.4 g each time, 3 times/d) for half a year. The control group was treated with the same amount of placebo therapy. The peripheral blood of the patient was collected and the cytokine, T lymphocyte subsets were detected.

Results

We found the oral administration of NAC could regulate Th17/Treg balance to resist inflammation in COPD patients. Serum testing showed that the proportion of Treg in CD4+ T cells has increased and the Th17/Treg ratio has decreased during the NAC treatment. In vitro studies, we found that NAC regulated Th17/Treg balance through Hypoxia Inducible Factor-1α pathway.

Conclusions

Our result could provide new diagnosis and treatment for elderly patients with COPD from the perspective of immunity ideas.

The elastin peptide VGVAPG increases CD4+ T-cell IL-4 production in patients with chronic obstructive pulmonary disease

Background

In chronic obstructive pulmonary disease (COPD), lung-infiltrating inflammatory cells secrete proteases and participate in elastin breakdown and genesis of elastin-derived peptides (EP). In the present study, we hypothesized that the pattern of T lymphocytes cytokine expression may be modulated by EP in COPD patients.

Methods

CD4⁺ and CD8⁺ T-cells, sorted from peripheral blood mononuclear cells (PBMC) collected from COPD patients (n = 29) and controls (n = 13) were cultured with or without EP. Cytokine expression in T-cell phenotypes was analyzed by multicolor flow cytometry, whereas desmosine concentration, a specific marker of elastin degradation, was measured in sera.

Results

Compared with control, the percentage of IL-4 (Th2) producing CD4⁺ T-cells was decreased in COPD patients (35.3 ± 3.4% and 26.3 ± 2.4%, respectively, p < 0.05), whereas no significant differences were found with IFN-γ (Th1) and IL-17A (Th17). Among COPD patients, two subpopulations were observed based on the percentage of IL-4 (Th2) producing CD4⁺ T-cells, of which only one expressed high IL-4 levels in association with high levels of desmosine and strong smoking exposure (n = 7). Upon stimulation with VGVAPG, a bioactive EP motif, the percentage of CD4⁺ T cells expressing IL-4 significantly increased in COPD patients (p < 0.05), but not in controls. The VGVAPG-induced increase in IL-4 was inhibited in the presence of analogous peptide antagonizing VGVAPG/elastin receptor (S-gal) interactions.

Conclusions

The present study demonstrates that the VGVAPG elastin peptide modulates CD4⁺ T-cells IL-4 production in COPD. Monitoring IL-4 in circulating CD4⁺ T-cells may help to better characterize COPD phenotypes and could open a new pharmacologic opportunity through CD4⁺ T-cells stimulation via the VGVAPG/S-gal receptor in order to favor an anti-inflammatory response in those COPD patients.

Effect of acupoint application on T lymphocyte subsets in patients with chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

The development of chronic obstructive pulmonary disease (COPD) is related to the T lymphocyte mediated inflammatory immune response and immune imbalance. The purpose of this systematic review was to evaluate the clinical efficacy and safety of acupoint application on T lymphocyte subsets in patients with COPD.

METHODS

We searched CNKI, Wan fang, Chongqing VIP, China Biology Medicine disc, PubMed, the Cochrane Library, and EMBASE for studies published as of Oct. 31, 2019. All randomized controlled trials of acupoint application on COPD patients that met the inclusion criteria were included. The Cochrane bias risk assessment tool was used for literature evaluation. RevMan5.3 software was used for meta-analysis.

RESULTS

Eight studies (combined n = 524) qualified based on the inclusion criteria. Compared with routine treatment alone, acupoint application combined with routine treatment can significantly increase the T lymphocyte CD4/CD8 ratio (MD 0.12, 95% CI 0.03-0.21, P < .01, I = 49%), reduce CD8 T-cells (MD-0.99, 95% CI-1.70-0.28, P < .001, I = 37%), reduce the times of acute exacerbations (MD-0.28, 95% CI-0.35-0.21, P < .001, I = 0), and improve the clinical efficacy (MD 1.30, 95% CI 1.14-1.48, P < .001, I = 39%).

CONCLUSION

Acupoint application can improve the CD4/CD8 ratio and CD8 T-cells in patients with COPD and has an auxiliary effect in reducing the times of acute exacerbations and improving clinical efficacy.

Immunodeficiency in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), characterized by progressive airway inflammation and irreversible airflow limitation, leads to serious decline in life quality. The acute exacerbation of COPD (AECOPD) results in high healthcare costs as well as a significant mortality rate. The most common cause of acute exacerbation is infection. Immune deficiency, which induces dysfunction of anti-infection, plays an important role in the pathogenesis of acute exacerbation. As described in this review, the immune dysfunction in patients with AECOPD can be a major focus of efforts to therapeutic strategy.

Cytokine-induced alterations of BAMBI mediate the reciprocal regulation of human Th17/Treg cells in response to cigarette smoke extract

In CD4+ T helper (Th) cells, transforming growth factor β (TGF‑β) is indispensable for the induction of both regulatory T (Treg) and interleukin‑17‑producing effector T helper (Th17) cells. Although BMP and activin membrane‑bound inhibitor (BAMBI) is part of a rheostat‑like mechanism for the regulation of TGF‑β signalling and autoimmune arthritis in mouse models, the underlying activity of BAMBI on the human Th17/Treg cell axis, particularly during exposure to cigarette smoke, remains to be elucidated. The present study aimed to further characterize BAMBI expression in human CD4+ cells, as well as immune imbalance during activation and cigarette smoke exposure. Results from the present study indicated that exposure to cigarette smoke extract partially suppressed Treg differentiation and promoted Th17 cell generation under stimulation by anti‑CD3/28 antibodies and TGF‑β1. Additionally, exposure to cigarette smoke induced an inhibition of phosphorylated‑Smad2/Smad3, which may have arisen from a concomitant enhancement of BAMBI expression. In conclusion, human BAMBI may function as a molecular switch to control TGF‑β signalling strength and the Th17/Treg cell balance, which may be used not only as a biomarker but also as a target of new treatment strategies for maintaining immune tolerance and for the treatment of smoking‑induced immune disorders.

Impacts of cigarette smoking on immune responsiveness: Up and down or upside down?

Cigarette smoking is associated with numerous diseases and poses a serious challenge to the current healthcare system worldwide. Smoking impacts both innate and adaptive immunity and plays dual roles in regulating immunity by either exacerbation of pathogenic immune responses or attenuation of defensive immunity. Adaptive immune cells affected by smoking mainly include T helper cells (Th1/Th2/Th17), CD4+CD25+ regulatory T cells, CD8+ T cells, B cells and memory T/B lymphocytes while innate immune cells impacted by smoking are mostly DCs, macrophages and NK cells. Complex roles of cigarette smoke have resulted in numerous diseases, including cardiovascular, respiratory and autoimmune diseases, allergies, cancers and transplant rejection etc. Although previous reviews have described the effects of smoking on various diseases and regional immunity associated with specific diseases, a comprehensive and updated review is rarely seen to demonstrate impacts of smoking on general immunity and, especially on major components of immune cells. Here, we aim to systematically and objectively review the influence of smoking on major components of both innate and adaptive immune cells, and summarize cellular and molecular mechanisms underlying effects of cigarette smoking on the immune system. The molecular pathways impacted by cigarette smoking involve NFκB, MAP kinases and histone modification. Further investigations are warranted to understand the exact mechanisms responsible for smoking-mediated immunopathology and to answer lingering questions over why cigarette smoking is always harmful rather than beneficial even though it exerts dual effects on immune responses.

Gut-lung axis: The microbial contributions and clinical implications

Gut microbiota interacts with host immune system in ways that influence the development of disease. Advances in respiratory immune system also broaden our knowledge of the interaction between host and microbiome in the lung. Increasing evidence indicated the intimate relationship between the gastrointestinal tract and respiratory tract. Exacerbations of chronic gut and lung disease have been shown to share key conceptual features with the disorder and dysregulation of the microbial ecosystem. In this review, we discuss the impact of gut and lung microbiota on disease exacerbation and progression, and the recent understanding of the immunological link between the gut and the lung, the gut-lung axis.

TGF-β/BAMBI pathway dysfunction contributes to peripheral Th17/Treg imbalance in chronic obstructive pulmonary disease

BMP and activin membrane-bound inhibitor (BAMBI) is postulated to inhibit or modulate transforming growth factor β (TGF-β) signaling. Furthermore, strong upregulation of BAMBI expression following in vitro infection of chronic obstructive pulmonary disease (COPD) lung tissue has been demonstrated. In this study, we investigated whether TGF-β/BAMBI pathway is associated with COPD. Blood samples were obtained from 27 healthy controls (HC), 24 healthy smokers (HS) and 29 COPD patients. Elevated Th17/Treg ratios, and increased levels of BAMBI protein and mRNA (in plasma and CD4(+) T cells respectively), were observed in COPD compared with HC and HS. BAMBI expression was first observed on human CD4(+) T cells, with a typical membrane-bound pattern. The enhanced plasma BAMBI levels in COPD positively correlated with the increased plasma TGF-β1 levels and Th17/Treg ratio. Together, an impaired TGF-β/BAMBI pathway may promote the inflammation leading to Th17/Treg imbalance, which is a new mechanism in smokers who develop COPD.

Imbalance between subsets of CD8(+) peripheral blood T cells in patients with chronic obstructive pulmonary disease

Background. CD8⁺ T lymphocytes are known to play a critical role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, systematic analyses of CD8⁺ T cell (Cytotoxic T cells, Tc) subsets in COPD patients have yet to be well conducted.

Methods. The whole Tc subsets, including Tc1/2/10/17, CD8⁺ regulatory T cells (Tregs) and CD8⁺α7⁺ T cells, were quantified by flow cytometry in peripheral blood from 24 stable COPD subjects (SCOPD), 14 patients during acute exacerbations (AECOPD), and 14 healthy nonsmokers (HN).

Results. Acute exacerbations of COPD were accompanied by elevated levels of circulating CD8⁺ T cells. Tc1 cells were increased in both SCOPD and AECOPD patients, whereas the percentage of Tc2 cells was decreased in SCOPD patients but remained normal in AECOPD patients. Tc17 cells were increased only in AECOPD patients, and the percentage of Tc10 cells was reduced in both SCOPD and AECOPD patients. The imbalances of pro/anti-inflammatory Tc subsets observed in COPD may be caused by the lack of Tc10 cells and the impaired anti-inflammatory capacity of CD8⁺ Tregs.

Conclusions. The imbalances between subsets of CD8⁺ peripheral blood T cells contribute to the immune response dysfunction in COPD pathogenesis.

COPD immunopathology

The immunopathology of chronic obstructive pulmonary disease (COPD) is based on the innate and adaptive inflammatory immune responses to the chronic inhalation of cigarette smoking. In the last quarter of the century, the analysis of specimens obtained from the lower airways of COPD patients compared with those from a control group of age-matched smokers with normal lung function has provided novel insights on the potential pathogenetic role of the different cells of the innate and acquired immune responses and their pro/anti-inflammatory mediators and intracellular signalling pathways, contributing to a better knowledge of the immunopathology of COPD both during its stable phase and during its exacerbations. This also has provided a scientific rationale for new drugs discovery and targeting to the lower airways. This review summarises and discusses the immunopathology of COPD patients, of different severity, compared with control smokers with normal lung function.

Cigarette Smoke Disturbs the Survival of CD8+ Tc/Tregs Partially through Muscarinic Receptors-Dependent Mechanisms in Chronic Obstructive Pulmonary Disease

BACKGROUND

CD8+ T cells (Cytotoxic T cells, Tc) are known to play a critical role in the pathogenesis of smoking related airway inflammation including chronic obstructive pulmonary disease (COPD). However, how cigarette smoke directly impacts systematic CD8+ T cell and regulatory T cell (Treg) subsets, especially by modulating muscarinic acetylcholine receptors (MRs), has yet to be well elucidated.

METHODS

Circulating CD8+ Tc/Tregs in healthy nonsmokers (n = 15), healthy smokers (n = 15) and COPD patients (n = 18) were evaluated by flow cytometry after incubating with anti-CD3, anti-CD8, anti-CD25, anti-Foxp3 antibodies. Peripheral blood T cells (PBT cells) from healthy nonsmokers were cultured in the presence of cigarette smoke extract (CSE) alone or combined with MRs agonist/antagonist for 5 days. Proliferation and apoptosis were evaluated by flow cytometry using Ki-67/Annexin-V antibodies to measure the effects of CSE on the survival of CD8+ Tc/Tregs.

RESULTS

While COPD patients have elevated circulating percentage of CD8+ T cells, healthy smokers have higher frequency of CD8+ Tregs. Elevated percentages of CD8+ T cells correlated inversely with declined FEV1 in COPD. CSE promoted the proliferation and inhibited the apoptosis of CD8+ T cells, while facilitated both the proliferation and apoptosis of CD8+ Tregs. Notably, the effects of CSE on CD8+ Tc/Tregs can be mostly simulated or attenuated by muscarine and atropine, the MR agonist and antagonist, respectively. However, neither muscarine nor atropine influenced the apoptosis of CD8+ Tregs.

CONCLUSION

The results imply that cigarette smoking likely facilitates a proinflammatory state in smokers, which is partially mediated by MR dysfunction. The MR antagonist may be a beneficial drug candidate for cigarette smoke-induced chronic airway inflammation.

The effect of SCF and ouabain on small intestinal motility dysfunction induced by gastric cancer peritoneal metastasis

The interstitial cells of Cajal (ICCs) play an important role in maintaining the normal function of gastrointestinal dynamics. In our previous study, we reported that, in advanced gastric cancer, the frequency of bowel movement is always reduced, due in part to the decreased number of ICCs. To investigate the impact of ICCs in gastric cancer, we established a mouse model of gastric cancer peritoneal metastasis using SGC-7901 gastric adenocarcinoma cells and their supernatant. Then, stem cell factor (SCF) and ouabain were used as therapeutic agents to improve gut dynamics. Our data showed that, compared with the normal mice, treatment with SGC-7901 cells and their supernatant led to a significant reduction of the muscle layer thickness, a decreased number of ICCs, broadened gaps between ICCs and surrounding cells, degeneration and necrosis of smooth muscle cells (SMCs), and infiltration of inflammatory cells. In contrast to SGC-7901 cell and supernatant treatment, SCF intervention caused mild submucosal edema and mitochondrial proliferation in the ICCs and SMCs. Additionally, ouabain treatment led to inflammatory cells infiltration into the submucosa and a decreased volume of ICCs. In conclusion, our data illustrated that, under the condition of gastric cancer peritoneal metastasis, the dysfunction of intestinal peristalsis may be related to pathological changes in ICCs. Moreover, we demonstrated that SCF treatment may help to improve intestinal dynamics by regulating the number and function of ICCs.