The mediating role of cytokine IL-6 on the relationship of FEV₁ upon 6-minute walk distance in chronic obstructive pulmonary disease

Anti-inflammatory effect of Anadenanthera colubrina var. cebil (Griseb.) Altschul in experimental elastase-induced pulmonary emphysema in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants have shown promise in the search for new treatments of pulmonary emphysema. Anadenanthera colubrina, a species native to the Caatinga biome in northeastern Brazil, is widely recognized and traditionally employed in the treatment of pulmonary diseases. Many studies corroborate popular knowledge about the medicinal applications of A. colubrina, which has demonstrated a remarkable variety of pharmacological properties, however, its anti-inflammatory and antioxidant properties are highlighted.

AIM OF THE STUDY

The objective of this study was to investigate the anti-inflammatory potential of the crude hydroethanolic extract of A. colubrina var. cebil (Griseb.) Altschul on pulmonary emphysema in rats as well as to determine its potential genotoxic and cytotoxic effects using the micronucleus assay.

MATERIALS AND METHODS

The stem bark of the plant was collected in Pimenteiras-PI and sample was extracted by maceration using 70% ethanol. A portion of the extract underwent phytochemical analyses using TLC and HPLC. In this study, 8-week-old, male Wistar rats weighing approximately ±200 g was utilized following approval by local ethics committee for animal experimentation (No. 718/2022). Pulmonary emphysema was induced through orotracheal instillation of elastase, and treatment with A. colubrina extract or dexamethasone (positive control) concomitantly during induction. Twenty-eight days after the initiation of the protocol, plasma was used for cytokine measurement. Bronchoalveolar lavage (BAL) was used for leukocyte count. After euthanasia, lung samples were processed for histological analysis and quantification of oxidative stress markers. The micronucleus test was performed by evaluating the number of polychromatic erythrocytes (PCE) with micronuclei (MNPCE) to verify potential genotoxic effects of A. colubrina. A differential count of PCE and normochromatic erythrocytes (NCE) was performed to verify the potential cytotoxicity of the extract. Parametric data were subjected to normality analysis and subsequently to analysis of variance and Tukey or Dunnett post-test, non-parametric data were treated using the Kruskal-Wallis test with Dunn's post-test for unpaired samples. P value < 0.05 were considered significant.

RESULTS

The A. colubrina extract did not show a significant increase in the number of MNPCE (p > 0.05), demonstrating low genotoxicity. No changes were observed in the PCE/NCE ratio of treated animals, compared with the vehicle, suggesting low cytotoxic potential of the extract. A significant reduction (p < 0.05) in neutrophilic inflammation was observed in the lungs of rats treated with the extract, evidenced by presence of these cells in both the tissue and BAL. The extract also demonstrated pulmonary antioxidant activity, with a significant decrease (p < 0.05) in myeloperoxidase, malondialdehyde, and nitrite levels. TNFα, IL-1β, and IL-6 levels, as well as alveolar damage, were significantly reduced in animals treated with A. colubrina extract. Phytochemical analyses identified the presence of phenolic compounds and hydrolysable tannins in the A. colubrina extract.

CONCLUSIONS

The findings of this study highlights the safety of the hydroethanolic extract of Anadenanthera colubrina, and demonstrates its potential as a therapeutic approach in the treatment of emphysema. The observed properties of this medicinal plant provide an optimistic outlook in the development of therapies for the treatment of pulmonary emphysema.

Mesenchymal stem cells attenuate the proinflammatory cytokine pattern in a guinea pig model of chronic cigarette smoke exposure

AIMS

Cigarette smoke often induces pulmonary and systemic inflammation. In animal models, mesenchymal stem cells (MSC) tend to ameliorate these effects. We aimed to explore the local and systemic expression of cytokines in guinea pigs chronically exposed to cigarette smoke, and their modifications by MSC.

MAIN METHODS

Concentrations of IL-1β, IL-6, IL-8, IL-12, TNF-α, INF-ɣ, TSG-6, MMP-9, TIMP-1, and/or TIMP-2 in serum and bronchoalveolar lavage (BALF) from animals exposed to tobacco smoke (20 cigarettes/day, 5 days/week for 10 weeks) were determined, and mRNA expression of some of them was measured in lung tissue. Intratracheal instillation of allogeneic bone marrow MSC (5x10⁶ cells in 1 ml) was done at week 2.

KEY FINDINGS

After cigarette smoke, IL-6 and IFN-γ increased in serum and BALF, while IL-1β and IL-12 decreased in serum, and TSG-6 and TIMP-2 increased in BALF. IL-1β had a paradoxical increase in BALF. MSC had an almost null effect in unexposed animals. The intratracheal administration of MSC in guinea pigs exposed to cigarette smoke was associated with a statistically significant decrease of IL-12 and TSG-6 in serum, as well as a decrease of IL-1β and IFN-γ and an increase in TIMP-1 in BALF. Concerning mRNA expression in lung tissue, cigarette smoke did not modify the relative amount of the studied transcripts, but even so, MSC decreased the IL-12 mRNA and increased the TIMP-1 mRNA.

SIGNIFICANCE

A single intratracheal instillation of MSC reduces the pulmonary and systemic proinflammatory pattern induced by chronic exposure to cigarette smoke in guinea pigs.

TRIAL REGISTRATION

Not applicable.

Is Frailty Diagnosis Important in Patients with COPD? A Narrative Review of the Literature

Frailty is prevalent in older adults and is related to a worsening functionality, quality of life, and health outcomes. Though there is an increasing interest in this field, the relationship between frailty and worsening COPD outcomes remains unknown. A narrative review of the literature with studies published between 2018 and 2022 was carried out to address three questions: the prevalence of frailty and other geriatric syndromes in COPD patients, the link between frailty and worsening health outcomes in COPD patients, and the non-pharmacological interventions performed in order to reverse frailty in these patients. A total of 25 articles were selected. Frailty prevalence ranged from 6% and 85.9%, depending on the COPD severity and the frailty measurement tool used. Frailty in COPD patients was related to a high prevalence of geriatric syndromes and to a high incidence of adverse events such as exacerbations, admissions, readmissions, and mortality. One study showed improvements in functionality after physical intervention. In conclusion, the prevalence of frailty is associated with a high incidence of geriatric syndromes and adverse events in COPD patients. The use of frailty screenings and a comprehensive geriatric assessment of COPD patients is advisable in order to detect associated problems and to establish individualized approaches for better outcomes.

Endothelial dysfunction: The possible link between cardiovascular comorbidities and phenomenon of inflammaging from COPD

Aging is a risk factor for many chronic noncommunicable diseases, including chronic obstructive pulmonary disease (COPD), which is often associated with cardiovascular disease (CVD). Moreover, aging is associated with a mild form of systemic inflammation. The aim of our study was to analyze the relationship between age, systemic and vascular inflammation, and the presence of CVD comorbidities in a stable COPD population. Forty COPD patients were divided into 2 age groups (<65 and ≥65 years of age), from which we collected the following inflammatory biomarkers: C-reactive protein, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and endothelin-1 (ET-1). Elderly COPD patients had more frequent exacerbation events per year (2 vs 1, P = .06), a higher prevalence of CVD (3 vs 2, P = .04), more limited exercise tolerance (6-minute walking test distance, 343 [283-403] vs 434 [384-484]; P = .02), and mild systemic inflammation (TNF-α, 9.02 [7.08-10.96] vs 6.48 [5.21-7.76]; P = .03; ET-1, 2.24 [1.76-2.71] vs 1.67 [1.36-1.98] pg/mL; P = .04). A weak correlation between age and ET-1 (r = 0.32, P = .04) was observed. Mild systemic inflammation, characterized by a slightly increased level of TNF-α, and endothelial dysfunction, marked by elevated ET-1, could be liaisons between aging, COPD, and CVD comorbidities.

Mapping the global research landscape and hotspot of exercise therapy and chronic obstructive pulmonary disease: A bibliometric study based on the web of science database from 2011 to 2020

Background: The application of exercise therapy (ET) in chronic obstructive pulmonary disease (COPD) is generating increasing clinical efficacy and social-economic value. In this study, research trends, evolutionary processes and hot topics in this field are detailed, as well as predictions of future development directions.

Methods: Search for literature in the field of COPD and ET and analyze data to generate knowledge graphs using VOSiewer and CiteSpace software. The time frame for the search was from 2011 to January 2021. Then we extracted full-text key information (such as title, journal category, publication date, author, country and institution, abstract, and keyword) and obtained the co-citation analysis. Use hierarchal clustering analysis software developed by VOSviewer to map common citations, and use Citespace software to plot trend networks.

Results: The United States topped the list with 27.91% of the number of articles posted, followed by the UK at 25.44%. Imperial College London was the highest number of article publications in institutions, followed by Maastricht University and the University of Toronto. The Royal Brompton Harefield NHS Foundation Trust was one of many research institutions and currently holds the highest average citations per item (ACI) value, followed by Imperial College London and the University of Leuven. Judging from the number of publications related to ET and COPD, it is mainly published in cell biology, respiratory pulmonary diseases, and rehabilitation experiments study medicine. The European Respiration Journal is the most widely published in this field, followed by the International Journal of Chronic Obstructive Pulmonary Disease and Respiratory Medicine.

Conclusion: COPD combined with ET is widely used in clinical practice and is on the rise. A distinctive feature of the field is multidisciplinary integration. Rehabilitation research for COPD involves multidisciplinary collaboration, tissue engineering, and molecular biology mechanism studies to help patients remodel healthy breathing. Multidisciplinary rehabilitation measures provide a solid foundation for advancing clinical efficacy in the field of COPD.

Frailty Assessment in a Stable COPD Cohort: Is There a COPD-Frail Phenotype?

The frailty syndrome increases the morbidity/mortality in older adults, and several studies have shown a higher prevalence of this syndrome in patients with Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to identify the characteristics of frail patients with COPD to define a new phenotype called "COPD-frail." We conducted a cross-sectional study in a cohort of patients with stable COPD, classified as either frail, pre-frail, or non-frail. Sociodemographic, clinical, and biochemical variables were compared between the three groups of patients. The study included 127 patients, of which 31 were frail, 64 were pre-frail, and 32 non-frail. All subjects had FEV1/FVC below the lower limit of normal (range Z-score: -1.66 and -5.32). Patients in the frail group showed significantly higher scores in the mMRC (modified Medical Research Council) scale, the CAT (COPD Assessment Test), and the BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity) index. They also showed differences in symptoms according to GOLD (Global Initiative for Chronic Obstructive Lung Disease), as well as more COPD exacerbations, less physical activity, more anxiety and depression symptoms based on HADS (Hospital Anxiety and Depression Scale), and lower hemoglobin, hematocrit, and 25-hydroxycholecalciferol levels. Variables with independent association with frailty included the mMRC score, the HAD index for depression and age. In summary, differential characteristics of frail patients with COPD encourage the definition of a "COPD-frail" phenotype that-if identified early-would allow performing interventions to prevent a negative impact on the morbidity/mortality of these patients.

Clinical significance of changes in serum inflammatory factors in patients with chronic obstructive pulmonary disease and pulmonary infection

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is often accompanied by pulmonary infection, inflammatory responses, decreased immunity, and decreased lung function. The relationships among the pulmonary inflammation index (PII), lung function, and immunity in COPD patients with pulmonary infection remain unclear.

METHODS

This retrospective observational study enrolled 234 participants (patients with COPD and pulmonary infection, patients with COPD without pulmonary infection, and healthy individuals) from January 2017 to December 2019.

RESULTS

Levels of interleukin (IL)-6 were lower and levels of IL-8 were higher in patients with COPD and pulmonary infection. Levels of white blood cells (WBCs), C-reactive protein (CRP), IL-6, IL-8, tumor necrosis factor (TNF)-α and CD8+ cells were higher, while levels of CD3+ and CD4+ cells, the CD4+/CD8+ ratio, forced expiratory volume in 1 s (FEV1), FEV1 % predicted (FEV1%pred), and FEV1/forced vital capacity (FVC) (FEV1%FVC) were lower in patients with COPD and pulmonary infection. Levels of WBCs, CRP, IL-6, IL-8, and TNF-α were negatively associated with FEV1, FEV1%pred and FEV1%FVC.

CONCLUSIONS

Patients with COPD and pulmonary infection have high PIIs, decreased immunity, and poor lung function. PII is closely related to lung function and may represent a useful biomarker for the assessment of patients with COPD and pulmonary infection.

Circulating Interleukin-6 (but Not Other Immune Mediators) Associates with Criteria for Fried's Frailty among Very Old Adults

Methods

One hundred and sixty-one very old patients (aged ≥80 years) devoid of cognitive decline were eligible for analyses. Clinical and biochemical data along with physical and cognitive assessments encompassing dual-energy X-ray scans and hand dynamometry were adopted to investigate frailty criteria, while circulating immune mediators (IFNγ, IL-2, IL-4, IL-6, IL-10, and TNFα) were assessed using high-throughput flow cytometry.

Results

Preliminarily, IL-6 correlated positively with waist-to-hip ratio and C-reactive protein and negatively with glycemia. In analyses controlled for these factors, serum levels of IL-6 were comparatively augmented among the very old participants with reduced grip strength (OR = 3.299; 95% CI 1.08–6.09; p=0.032) and among those with slow walk speed (OR = 2.460; 95% CI 1.16–7.05; p=0.022).

Conclusions

Our study shows a strong negative correlation of IL-6 levels with Fried's frailty components of grip strength and walk speed in very old adults, regardless of confounding factors.

Pathobiology of frailty in lung disease

Frailty is a clinical state of vulnerability to stressors resulting from cumulative alterations in multiple physiological and molecular systems. Frailty assessment in patients with chronic disease is useful for identifying those who are at increased risk for poor clinical and patient reported outcomes. Due to biobehavioral changes purported to cause both frailty and certain chronic lung diseases, patients with lung disease appear susceptible to frailty and prone to developing it decades earlier than community dwelling healthy populations. Herein, we review the literature and potential pathobiological mechanisms underpinning associations between frailty in lung disease and age, sex, comorbidity and symptom burden, severity of lung disease, inflammatory biomarkers, various clinical parameters, body composition measures, and physical activity levels. We also propose a multipronged program of future research focused on improving the accuracy and precision of frailty measurement in lung disease, identifying blood-based biomarkers and measures of body composition for frailty, determining whether subphenotypes of frailty with distinct pathobiology exist, and developing personalized interventions that target the specific underlying mechanisms causing frailty.

Shared mechanisms of multimorbidity in COPD, atherosclerosis and type-2 diabetes: the neutrophil as a potential inflammatory target

Multimorbidity is increasingly common and current healthcare strategies are not always aligned to treat this complex burden of disease. COPD, type-2 diabetes mellitus (T2D) and cardiovascular disease, especially atherosclerosis, occur more frequently together than expected, even when risk factors such as smoking, obesity, inactivity and poverty are considered. This supports the possibility of unifying mechanisms that contribute to the pathogenesis or progression of each condition.Neutrophilic inflammation is causally associated with COPD, and increasingly recognised in the pathogenesis of atherosclerosis and T2D, potentially forming an aetiological link between conditions. This link might reflect an overspill of inflammation from one affected organ into the systemic circulation, exposing all organs to an increased milieu of proinflammatory cytokines. Additionally, increasing evidence supports the involvement of other processes in chronic disease pathogenesis, such as cellular senescence or changes in cellular phenotypes.This review explores the current scientific evidence for inflammation, cellular ageing and cellular processes, such as reactive oxygen species production and phenotypic changes in the pathogenesis of COPD, T2D and atherosclerosis; highlighting common mechanisms shared across these diseases. We identify emerging therapeutic approaches that target these areas, but also where more work is still required to improve our understanding of the underlying cellular biology in a multimorbid disease setting.

What is the impact of different spirometric criteria on the prevalence of spirometrically defined COPD and its comorbidities? Results from the population-based KORA study

Background

There is an ongoing debate about the appropriate spirometric criterion for airway obstruction to detect COPD. Furthermore, the association of different criteria with comorbidity prevalence and inflammatory biomarkers in advanced age is unclear.

Materials and methods

Spirometry was performed in a population-based study (n=2,256) covering an age range of 41–90 years. COPD was spirometrically determined either by a fixed ratio (FR) of <0.7 for forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) or by FEV₁/FVC below the lower limit of normal (LLN). Comorbidity prevalences and circulating biomarker levels (C-reactive protein [CRP], interleukin [IL]-6) were compared between subjects with or without COPD by the two criteria using logistic and multiple regression models, adjusting for sex and age.

Results

The prevalence of spirometrically defined COPD by FR increased with age from 10% in subjects aged <65 years to 26% in subjects aged ≥75 years. For LLN-defined COPD, it remained below 10% for all age groups. Overall, COPD diagnosis was not associated with specific comorbidities, except for a lower prevalence of obesity in both FR- and LLN-defined cases. Both CRP and IL-6 tended to be higher in cases by both criteria.

Conclusion

In a population-based cohort of adults up to the age of 90 years, the prevalence of spirometrically defined COPD was higher for the FR criterion than for the LLN criterion. This difference increased with age. Neither prevalences of common comorbidities nor levels of the biomarkers, CRP or IL-6, were conclusively associated with the selection of the COPD criterion. Results have to be considered in light of the predominantly mild cases of airway obstruction in the examined study population.