Metabolic syndrome is associated with increased risk of acute exacerbation of COPD: a preliminary study

Metabolic syndrome in patients with COPD: Causes and pathophysiological consequences

BACKGROUND

Decreased physical activity significantly increases the probability of prevalent metabolic syndrome (MetS) with substantial impact on the expected course of COPD.

OBJECTIVE

Our research aims to assess the metabolic consequences of chronic obstructive pulmonary disease (COPD) and evaluate the prevalence of MetS and its interrelations with age, sex, comorbidities, drug intake, degree of decreased lung function, nutritional status, physical activity and quality of life.

METHODS

A cross-sectional study was performed on a random sample (n = 401) at the Department of Pulmonary Rehabilitation of the National Koranyi Institute of Pulmonology from March 1, 2019 to March 1, 2020 in Budapest, Hungary. Anthropometric and respiratory function tests and laboratory parameters of all patients were registered.

RESULTS

MetS occurred in 59.1% of COPD patients with significant gender difference (male: 49.7% female: 67.6%). Concerning BMI, the prevalence of MetS was higher with BMI≥25 kg m-2 (P < 0.0001). Patients with this syndrome had significantly worse FEV1%pred (43 (30-56) vs. 47 (36-61); P = 0.028), lower quality of life (CAT: 26 (21-32) vs. 24.5 (19-29); P = 0.049) and significantly more frequent exacerbations (2 (1-3) vs.1 (0-2); P < 0.05), than patients without MetS. The prevalence of comorbidities were higher in overweight/obese patients (BMI> 25 kg m-2).

CONCLUSIONS

In COPD patients MetS negatively affect respiratory function and quality of life and promotes exacerbations of the disease. MetS is related to nutritional status and the level of systemic inflammation in COPD patients.

Impact of insomnia and obstructive sleep apnea on the risk of acute exacerbation of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major health burden worldwide. Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is characterized by worsening of patients' respiratory symptoms that requires a modification in medication. This event could accelerate disease progression and increase the risk of hospital admissions and mortality. Both insomnia and obstructive sleep apnea (OSA) are prevalent in patients with COPD, and are linked to increased susceptibility to AECOPD. Improper treatment of insomnia may increase the risk of adverse respiratory outcomes for patients with COPD, while effective continuous positive airway pressure (CPAP) treatment may reduce the risk of AECOPD and mortality in patients with overlap syndrome. Sleep disorders should be considered in clinical management for COPD.

Metabolic Syndrome and Abnormal Peri-Organ or Intra-Organ Fat (APIFat) Deposition in Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disorder with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Systemic inflammation is involved in the pathogenesis of COPD and can also predispose to metabolic disorders (e.g., metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD)). Such comorbidities can negatively affect COPD outcomes, cardiovascular risk, and quality of life. Apart from NAFLD, abnormal peri-organ or intra-organ fat (APIFat) could be considered as markers for cardiometabolic diseases and even for COPD. The present narrative review considers the associations of COPD with MetS, NAFLD, and other APIFat, including epicardial, perirenal, peripancreatic, and intramuscular adipose tissue. Further research is needed to define these relationships and identify any potential clinical implications.

Witnessed sleep apneas together with elevated plasma glucose are predictors of COPD exacerbations

Objective

Sleep apnea and elevated plasma glucose associates with inflammation which associates with the risk of COPD exacerbations. We investigated the risk of exacerbations in individuals with COPD, witnessed sleep apneas, and elevated plasma glucose.

Methods

From the Copenhagen City Heart Study cohort, we identified 564 individuals with COPD (forced expiratory volume in 1 sec divided by forced vital capacity, FEV₁/FVC<0.70), no asthma, above 40 years of age, and more than 10 pack-years of smoking history, with information on witnessed apneas and levels of plasma glucose. We prospectively recorded hospital admissions with COPD exacerbations during maximum available follow-up (26.3 years; mean 10.7 years). Cox-regression analyses were used to analyze the risk of COPD exacerbations.

Results

We identified 74 (13%) individuals with sleep apnea without elevated plasma glucose, 70 (12%) had elevated plasma glucose (above 6.9 mM (>125 mg/dL)) without sleep apnea and 11 individuals had the presence of both conditions. In univariable analysis, witnessed apneas together with elevated plasma glucose had a high risk of exacerbations, hazard ratio (HR) = 5.81 (2.34–14.4, p = 0.0001) compared to those without sleep apnea and without elevated plasma glucose. Multivariable analysis, adjusting for several risk factors of exacerbations, showed a similar result, HR = 3.45 (1.13–10.5, p = 0.03). Both presence of sleep apnea without elevated plasma glucose and the presence of elevated plasma glucose without sleep apnea showed no associations with the risk of exacerbations.

Conclusions

Witnessed sleep apneas in COPD are associated with increased risk of exacerbations, but only among those with elevated plasma glucose.

Metabolic Syndrome in Early Chronic Obstructive Pulmonary Disease: Gender Differences and Impact on Exacerbation and Medical Costs

Background

Metabolic syndrome (MetS) is a well-known comorbidity of chronic obstructive pulmonary disease (COPD). However, their interrelationship, particularly in early COPD, remains unclear. Therefore, we aimed to assess the prevalence and clinical characteristics of MetS in patients with early COPD, and to explore the impact of MetS on the frequency of COPD exacerbations and associated medical costs.

Patients and methods

We retrospectively enrolled 43,874 subjects from the KNHANES, including 2164 patients with early COPD (≥40 years old), recorded smoking history, and Global Initiative for Chronic Obstructive Lung Disease spirometric grade I or II, with data linked to the NHI database. We extracted and analyzed data regarding health-care utilization and medical costs for 5 years (2007 to 2012).

Results

Among 2164 patients with early COPD, the prevalence of MetS was 31.2%, and it was higher in women than in men (35.1% vs. 26.6%; P<0.001). Patients with MetS were older and had lower pulmonary function and greater number of comorbidities. The frequency of moderate-to-severe COPD exacerbations for 5 years was significantly higher in women with MetS than in those without MetS (5.8/year vs. 4.9/year; P=0.02). After adjusting for confounding factors, the risk for moderate-to-severe exacerbation was significantly greater in women with MetS (IRR, 1.17; 95% CI, 1.01 to 1.36; P=0.03). COPD exacerbations leading to hospitalization and medical expenses were also higher in women with MetS than in those without MetS.

Conclusion

MetS is more prevalent in women with early COPD. MetS increased the frequency of exacerbations and the medical costs in women with early COPD.

Metformin use mitigates the adverse prognostic effect of diabetes mellitus in chronic obstructive pulmonary disease

Background and objective

Among patients with chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM) is a common comorbidity and is probably associated with increased systemic inflammation and worse prognosis. Metformin, with its pleiotropic anti-inflammatory and antioxidant actions, may offer theoretical benefits in COPD patients with DM. Thus, this study aimed to investigate the effects of DM and metformin use on mortality in the clinical trajectory of COPD.

Methods

This was a retrospective cohort study comprising patients with spirometry-confirmed COPD and an age of ≥40 years from 2008 to 2014. The primary outcome of interest was all-cause mortality. We evaluated the effects of DM on mortality through the clinical course of COPD and we also assessed the impact of metformin use on survival of the COPD population.

Results

Among 4231 COPD patients, 556 (13%) had DM, and these patients had 1.62 times higher hazards of 2-year mortality than those without DM (95% confidence interval [CI], 1.15–2.28) after adjusting for age, gender, COPD stage, comorbidities and prior COPD hospitalization. Over a 2-year period, metformin users had a significantly lower risk of death (hazard ratio, 0.46; 95% CI, 0.23–0.92) compared with non-metformin users in patients with coexistent COPD and DM. Moreover, metformin users had similar survival to COPD patients without DM.

Conclusions

This study shows that DM is associated with an increased risk of death in COPD patients and metformin use seems to mitigate the hazard. Our findings suggest a potential role of metformin in the management of DM in COPD.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1035-9) contains supplementary material, which is available to authorized users.

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

Dapagliflozin-lowered blood glucose reduces respiratory Pseudomonas aeruginosa infection in diabetic mice

BACKGROUND AND PURPOSE

Hyperglycaemia increases glucose concentrations in airway surface liquid and increases the risk of pulmonary Pseudomonas aeruginosa infection. We determined whether reduction of blood and airway glucose concentrations by the anti-diabetic drug dapagliflozin could reduce P. aeruginosa growth/survival in the lungs of diabetic mice.

EXPERIMENTAL APPROACH

The effect of dapagliflozin on blood and airway glucose concentration, the inflammatory response and infection were investigated in C57BL/6J (wild type, WT) or leptin receptor-deficient (db/db) mice, treated orally with dapagliflozin prior to intranasal dosing with LPS or inoculation with P. aeruginosa. Pulmonary glucose transport and fluid absorption were investigated in Wistar rats using the perfused fluid-filled lung technique.

KEY RESULTS

Fasting blood, airway glucose and lactate concentrations were elevated in the db/db mouse lung. LPS challenge increased inflammatory cells in bronchoalveolar lavage fluid from WT and db/db mice with and without dapagliflozin treatment. P. aeruginosa colony-forming units (CFU) were increased in db/db lungs. Pretreatment with dapagliflozin reduced blood and bronchoalveolar lavage glucose concentrations and P. aeruginosa CFU in db/db mice towards those seen in WT. Dapagliflozin had no adverse effects on the inflammatory response in the mouse or pulmonary glucose transport or fluid absorption in the rat lung.

CONCLUSION AND IMPLICATIONS

Pharmacological lowering of blood glucose with dapagliflozin effectively reduced P. aeruginosa infection in the lungs of diabetic mice and had no adverse pulmonary effects in the rat. Dapagliflozin has potential to reduce the use, or augment the effect, of antimicrobials in the prevention or treatment of pulmonary infection.

Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease with high prevalence and substantial associated economical burden. A significant determinant of quality of life, long-term survival, and health care costs is an acute exacerbation of COPD. Acute exacerbations are provoked by respiratory viruses, altered airway microbiome, and environmental factors. The current treatment options are limited. In order to develop specific therapeutic measures, it is important to understand how acute exacerbations evolve. This review focuses on pathophysiology of stable and exacerbated COPD.

The Level of Cholesterol in COPD Patients with Severe and Very Severe Stage of the Disease

BACKGROUND

High blood cholesterol is part of metabolic syndrome and can be caused by medical conditions or bad dietary habits.

AIM

The aim of the study was to investigate the prevalence of hypercholesterolemia in privies diagnosed patients with the severe and very severe stage of COPD, which were stable.

MATERIAL AND METHODS

We investigated 100 subjects, all of them smokers, with smoking status >10 years, stratified into two groups: with severe and very severe stage of the disease. It was clinical, randomized, cross-sectional study. Besides demographic parameters and functional parameters, body mass index, cholesterol, LDL, and HDL were investigated.

RESULTS

In the group of patients with very severe COPD were recorded significantly higher average values of cholesterol (6.16 ± 1.5 vs. 5.61 ± 1.1, p = 0.039). As independent significant factors influencing cholesterol in the group with a very severe COPD were confirmed the age of the patients (p = 0.005), LDL (p = 0.004) and HDL (p = 0.002). In the group with severe COPD, only LDL was confirmed as an independent significant factor that has an impact on cholesterol (p < 0.0001).

CONCLUSION

The results of our survey demonstrated a high level of blood cholesterol and LDL, and low level of blood HDL in both investigated group's patients with COPD.

The chronic obstructive pulmonary disease comorbidity spectrum in Japan differs from that in western countries

Patients with Chronic Obstructive Pulmonary Disease (COPD) frequently suffer from various comorbidities, such as cardiovascular disease, osteoporosis, depression, malnutrition, metabolic syndrome, diabetes, and lung cancer. These comorbidities have a significant impact on disease severity and survival. In fact, guidelines from both the Global Initiative for Chronic Obstructive Lung Disease and the Japanese Respiratory Society recommend that physicians take comorbidities into account when they evaluate COPD severity. These guidelines also emphasize the importance of managing comorbidities alongside airway obstruction in COPD. The mechanisms by which the many COPD-related comorbidities develop are still unclear. Aging and smoking are well-established as major factors. However, systemic inflammation may also contribute to the disease process. Having developed from the classical theory to differentiate COPD patients into "pink puffers" and "blue bloaters", COPD is now generally considered as a heterogeneous condition. On this point, we have noticed that the characteristics of Japanese COPD patients tend to differ from those of Westerners. Specifically, Japanese patients tend to be older, to have lower body mass index, to suffer from emphysema-dominant lung disease, and to experience exacerbations less frequently. The comorbidity spectrum of Japanese COPD patients also seems to differ from that of Westerners. For instance, in Japanese patients, cardiovascular disease and metabolic syndrome are less prevalent, whereas osteoporosis and malnutrition are more frequent. In order to treat Japanese COPD patients optimally, we must pay particular attention to their unique demographics and comorbidity spectrum, which contrast with those of Western COPD patients.

Comorbidities and Chronic Obstructive Pulmonary Disease: Prevalence, Influence on Outcomes, and Management

Comorbidities impact a large proportion of patients with chronic obstructive pulmonary disease (COPD), with over 80% of patients with COPD estimated to have at least one comorbid chronic condition. Guidelines for the treatment of COPD are just now incorporating comorbidities to their management recommendations of COPD, and it is becoming increasingly clear that multimorbidity as well as specific comorbidities have strong associations with mortality and clinical outcomes in COPD, including dyspnea, exercise capacity, quality of life, healthcare utilization, and exacerbation risk. Appropriately, there has been an increased focus upon describing the burden of comorbidity in the COPD population and incorporating this information into existing efforts to better understand the clinical and phenotypic heterogeneity of this group. In this article, we summarize existing knowledge about comorbidity burden and specific comorbidities in COPD, focusing on prevalence estimates, association with outcomes, and existing knowledge about treatment strategies.

Metabolic syndrome in hospitalized patients with chronic obstructive pulmonary disease

Introduction. The metabolic syndrome (MS) affects 21-53% of patients with chronic obstructive pulmonary disease (COPD) with a higher prevalence in the early stages of COPD, with results being highly variable between studies. MS may also affect natural course of COPD-number of exacerbations, quality of life and lung function. Aim. To examine the prevalence of MS and its correlation with comorbidities and COPD characteristics in patients with COPD admitted for exacerbation. Material and methods. 152 patients with COPD admitted for exacerbation were studied for presence of MS. All of them were also assessed for vitamin D status and diabetes mellitus type 2 (DM). Data were gathered for smoking status and exacerbations during the last year. All patients completed CAT (COPD assessment test) and mMRC (Modified Medical Research Council Dyspnea scale) questionnaires and underwent spirometry. Duration of current hospital stay was recorded. Results. 25% of patients have MS. 23.1% of the male and 29.5% of the female patients have MS (p > 0.05). The prevalence of MS in this study is significantly lower when compared to a national representative study (44.6% in subjects over 45 years). 69.1% of all patients and 97.4% from MS patients have arterial hypertension. The presence of MS is associated with significantly worse cough and sleep (1st and 7th CAT questions; p = 0.002 and p = 0.001 respectively) and higher total CAT score (p = 0.017). Average BMI is 27.31. None of the patients have MS and BMI <25. There is a correlation between the presence of MS and DM (p = 0.008) and with the number of exacerbations in the last year (p = 0.015). There is no correlation between the presence of MS and the pulmonary function. Conclusion. This study among hospitalized COPD patients finds comparable but relatively low prevalence of MS (25%) compared to previously published data (21-53%) and lower prevalence compared to general population (44.6%). MS may impact quality of life and the number of exacerbations of COPD. Having in mind that MS is more common in the early stages and decreases with COPD progression, the COPD patients admitted for exacerbation may be considered as having advanced COPD.

The existence of bronchiectasis predicts worse prognosis in patients with COPD

Bronchiectasis is prevalent in patients with COPD. The objective of this study was to assess the clinical characteristics and prognostic value of bronchiectasis in patients with COPD in China. Data from patients diagnosed with COPD at the Shanghai Pulmonary Hospital between January 2009 and December 2013 were retrospectively collected and analyzed. SPSS statistical software was used to analyze the data. Data from 896 patients with COPD were analyzed. Bronchiectasis was present in 311 patients. The isolation of pseudomonas aeruginosa (PA) from sputum was the variable most significantly associated with the presence of bronchiectasis in patients with COPD (hazard ratio (HR), 2.93; 95% confidence interval (CI), 1.35–6.37; P = 0.007). During follow-up (median of 21 months; interquartile range: 10-39 months), there were 75 deaths, of which 39 were in the bronchiectasis group. The presence of bronchiectasis (HR, 1.77; 95% CI, 1.02–3.08; P = 0.043) was associated with an increase in all-cause mortality in patients with COPD. These results suggest that bronchiectasis in patients with COPD was associated with the isolation of PA from the sputum. Bronchiectasis was an independent risk factor for all-cause mortality in patients with COPD.

Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid

Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection.

Prevention of Exacerbations in Chronic Obstructive Pulmonary Disease: Knowns and Unknowns

The 2011 recommendations of the Global initiative for chronic Obstructive Lung Disease (GOLD) constituted a major paradigm shift in COPD management since they set 2 major goals for the assessment and management of patients: (1) the reduction of their current level of symptoms (i.e., treat the patient today); and (2) the reduction of their risk of exacerbations (i.e., prevent them tomorrow). Exacerbations are not only an important clinical endpoint in patients with COPD, but they are also a risk factor themselves for additional adverse outcomes since they have been shown to increase the risk for mortality, to accelerate the decline in pulmonary function, and to decrease health status and quality of life. Despite their importance, many unanswered questions related to exacerbations remain. The purpose of this review is to discuss: (1)knowns and unknowns in our current understanding of exacerbations, (2) what known factors increase their risk, and (3) how to best prevent them.

COPD patients with and without metabolic syndrome: clinical and functional differences

Chronic obstructive pulmonary disease (COPD) and the metabolic syndrome (MetS) are considered public health challenges of the 21st century. The coexistence of MetS in COPD patients and any clinical differences between COPD patients with and without MetS have not been extensively studied. We aimed to describe the clinical characteristics of patients with MetS and COPD. An observational, multicenter study of 375 patients hospitalized for a COPD exacerbation with spirometric confirmation was performed. We measured the components of the MetS and collected comorbidity information using the Charlson index and other conditions. Dyspnea, use of steroids, exacerbations, and hospitalizations were also investigated. The overall prevalence of MetS in COPD patients was 42.9 %, was more frequent in women (59.5 %) than men (40.8 %), p = 0.02, but with no differences in age and smoking history. COPD patients with MetS had greater % predicted FEV1, more dyspnea, and more comorbidity and used more inhaled steroids (all p < 0.05). Diabetes, osteoporosis, coronary artery disease, and heart failure were more frequent in patients with MetS. They had been hospitalized more frequently for any cause but not for COPD. In multivariate analysis, the presence of MetS was independently associated with greater FEV1, inhaled steroids use, osteoporosis, diabetes, and heart failure. MetS is a frequent condition in COPD patients, and it is associated with greater FEV1, more dyspnea, and more comorbidities.

Endogenous testosterone level and testosterone supplementation therapy in chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis

OBJECTIVE

Low testosterone level may be a reversible risk factor for functional disability and deterioration in patients with chronic obstructive pulmonary disease (COPD). We sought to systematically assess the endogenous testosterone levels and effect of testosterone therapy on exercise capacity and health-related quality of life (HRQoL) outcomes in COPD patients, as well as to inform guidelines and practice.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched PubMed, Scopus, Cochrane Library, CINAHL, Health Source Nursing and PsychINFO and the reference lists of retrieved articles published before May 2012.

INCLUSION CRITERIA

Observational studies on endogenous testosterone levels in people with chronic lung disease compared with controls, or randomised controlled trials (RCTs) on testosterone therapy for exercise capacity and/or HRQoL outcomes in COPD patients were eligible.

DATA EXTRACTION AND ANALYSIS

Data on the mean difference in endogenous total testosterone (TT) values, and the mean difference in exercise capacity and HRQoL values were extracted and pooled using random effects meta-analysis.

RESULTS

Nine observational studies in 2918 men with COPD reported consistently lower levels of TT compared with controls (weighted mean difference was -3.21 nmol/L (95% CI -5.18 to -1.23)). Six RCTs in 287 participants yielded five studies on peak muscle strength and peak cardiorespiratory fitness outcomes (peak oxygen uptake (VO2) and workload) and three studies on HRQoL outcomes. Testosterone therapies significantly improved peak muscle strength (standardised mean difference (SMD) was 0.31 (95% CI 0.05 to 0.56)) and peak workload (SMD was 0.27 (95% CI 0.01 to 0.52)) compared with control conditions (all but one used placebo), but not peak VO2 (SMD was 0.21 (95% CI -0.15 to 0.56)) or HRQoL (SMD was -0.03 (95% CI -0.32 to 0.25)).

CONCLUSIONS

Men with COPD have clinically relevant lower than normal TT levels. Insufficient evidence from short-term studies in predominately male COPD patients suggests that testosterone therapy improves exercise capacity outcomes, namely peak muscle strength and peak workload.

Treating influenza with statins and other immunomodulatory agents

Statins not only reduce levels of LDL-cholesterol, they counteract the inflammatory changes associated with acute coronary syndrome and improve survival. Similarly, in patients hospitalized with laboratory-confirmed seasonal influenza, statin treatment is associated with a 41% reduction in 30-day mortality. Most patients of any age who are at increased risk of influenza mortality have chronic low-grade inflammation characteristic of metabolic syndrome. Moreover, differences in the immune responses of children and adults seem responsible for the low mortality in children and high mortality in adults seen in the 1918 influenza pandemic and in other acute infectious and non-infectious conditions. These differences probably reflect human evolutionary development. Thus the host response to influenza seems to be the major determinant of outcome. Outpatient statins are associated with reductions in hospitalizations and deaths due to sepsis and pneumonia. Inpatient statins are also associated with reductions in short-term pneumonia mortality. Other immunomodulatory agents--ACE inhibitors (ACEIs), angiotensin receptor blockers (ARBs), PPARγ and PPARα agonists (glitazones and fibrates) and AMPK agonists (metformin)--also reduce mortality in patients with pneumonia (ACEIs, ARBs) or in mouse models of influenza (PPAR and AMPK agonists). In experimental studies, treatment has not increased virus replication. Thus effective management of influenza may not always require targeting the virus with vaccines or antiviral agents. Clinical investigators, not systems biologists, have been the first to suggest that immunomodulatory agents might be used to treat influenza patients, but randomized controlled trials will be needed to provide convincing evidence that they work. To guide the choice of which agent(s) to study, we need new types of laboratory research in animal models and clinical and epidemiological research in patients with critical illness. These studies will have crucial implications for global public health. During the 2009 H1N1 influenza pandemic, timely and affordable supplies of vaccines and antiviral agents were unavailable to more than 90% of the world's people. In contrast, statins and other immunomodulatory agents are currently produced as inexpensive generics, global supplies are huge, and they would be available to treat patients in any country with a basic health care system on the first pandemic day. Treatment with statins and other immunomodulatory agents represents a new approach to reducing mortality caused by seasonal and pandemic influenza.

COPD and the metabolic syndrome: an intriguing association

Chronic Obstructive Pulmonary Disease (COPD) has been recently recognized as a condition involving more than the lungs. The presence of common factors in COPD and in other chronic extra-pulmonary diseases, as well as the co-existence of these conditions in the same adult individual, supports the hypothesis of a shared pathogenetic pathway. We will here review the interplay between coexisting COPD and the metabolic syndrome (MS), based on the most updated knowledge. We will discuss this clinical condition from the definition, to the pathophysiology and to the clinical implications. Basically, MS is more likely to be present in a COPD patients, and increased levels of circulatory pro-inflammatory proteins from both the lung and adipose tissue coincide in these patients. The relative impact of the coexisting COPD and MS may depend on several factors: the presence of physical inactivity and of systemic inflammation related to a smoking habit, sedentary lifestyle, airway inflammation and obstruction, adipose tissue and inflammatory marker activation. More studies will be required to elucidate the association between COPD and MS and to formulate individualized management approaches for this specific disease phenotype.

Metformin reduces airway glucose permeability and hyperglycaemia-induced Staphylococcus aureus load independently of effects on blood glucose

BACKGROUND

Diabetes is a risk factor for respiratory infection, and hyperglycaemia is associated with increased glucose in airway surface liquid and risk of Staphylococcus aureus infection.

OBJECTIVES

To investigate whether elevation of basolateral/blood glucose concentration promotes airway Staphylococcus aureus growth and whether pretreatment with the antidiabetic drug metformin affects this relationship.

METHODS

Human airway epithelial cells grown at air-liquid interface (±18 h pre-treatment, 30 μM-1 mM metformin) were inoculated with 5×10(5) colony-forming units (CFU)/cm(2) S aureus 8325-4 or JE2 or Pseudomonas aeruginosa PA01 on the apical surface and incubated for 7 h. Wild-type C57BL/6 or db/db (leptin receptor-deficient) mice, 6-10 weeks old, were treated with intraperitoneal phosphate-buffered saline or 40 mg/kg metformin for 2 days before intranasal inoculation with 1×10(7) CFU S aureus. Mice were culled 24 h after infection and bronchoalveolar lavage fluid collected.

RESULTS

Apical S aureus growth increased with basolateral glucose concentration in an in vitro airway epithelia-bacteria co-culture model. S aureus reduced transepithelial electrical resistance (RT) and increased paracellular glucose flux. Metformin inhibited the glucose-induced growth of S aureus, increased RT and decreased glucose flux. Diabetic (db/db) mice infected with S aureus exhibited a higher bacterial load in their airways than control mice after 2 days and metformin treatment reversed this effect. Metformin did not decrease blood glucose but reduced paracellular flux across ex vivo murine tracheas.

CONCLUSIONS

Hyperglycaemia promotes respiratory S aureus infection, and metformin modifies glucose flux across the airway epithelium to limit hyperglycaemia-induced bacterial growth. Metformin might, therefore, be of additional benefit in the prevention and treatment of respiratory infection.

Mechanisms of acute exacerbation of respiratory symptoms in chronic obstructive pulmonary disease

Exacerbations of chronic obstructive respiratory disease (ECOPD) are acute events characterized by worsening of the patient's respiratory symptoms, particularly dyspnoea, leading to change in medical treatment and/or hospitalisation. AECOP are considered respiratory diseases, with reference to the respiratory nature of symptoms and to the involvement of airways and lung. Indeed respiratory infections and/or air pollution are the main causes of ECOPD. They cause an acute inflammation of the airways and the lung on top of the chronic inflammation that is associated with COPD. This acute inflammation is responsible of the development of acute respiratory symptoms (in these cases the term ECOPD is appropriate). However, the acute inflammation caused by infections/pollutants is almost associated with systemic inflammation, that may cause acute respiratory symptoms through decompensation of concomitant chronic diseases (eg acute heart failure, thromboembolism, etc) almost invariably associated with COPD. Most concomitant chronic diseases share with COPD not only the underlying chronic inflammation of the target organs (i.e. lungs, myocardium, vessels, adipose tissue), but also clinical manifestations like fatigue and dyspnoea. For this reason, in patients with multi-morbidity (eg COPD with chronic heart failure and hypertension, etc), the exacerbation of respiratory symptoms may be particularly difficult to investigate, as it may be caused by exacerbation of COPD and/or ≥ comorbidity, (e.g. decompensated heart failure, arrhythmias, thromboembolisms) without necessarily involving the airways and lung. In these cases the term ECOPD is inappropriate and misleading.

Inflammation in COPD: implications for management

Chronic obstructive pulmonary disease (COPD) is recognized by the Global Initiative for Chronic Obstructive Lung Disease guidelines as an inflammatory disease state, and treatment rationales are provided accordingly. However, not all physicians follow or are even aware of these guidelines. Research has shown that COPD inflammation involves multiple inflammatory cells and mediators and the underlying pathology differs from asthma inflammation. For these reasons, therapeutic agents that are effective in asthma patients may not be optimal in COPD patients. COPD exacerbations are intensified inflammatory events compared with stable COPD. The clinical and systemic consequences believed to result from the chronic inflammation observed in COPD suggest that inflammation intensity is a key factor in COPD and exacerbation severity and frequency. Although inhaled corticosteroids are commonly used and are essential in asthma management, their efficacy in COPD is limited, with only a modest effect at reducing exacerbations. The importance of inflammation in COPD needs to be better understood by clinicians, and the differences in inflammation in COPD versus asthma should be considered carefully to optimize the use of anti-inflammatory agents.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.

The association of low bone mineral density with systemic inflammation in clinically stable COPD

Chronic obstructive pulmonary disease (COPD) is known to be a systemic inflammatory disease which affects the function of many organs, and the low bone mineral density (BMD) may be the result of systemic inflammation. The aim of the present study was to explore the association of BMD with systemic inflammation in patients with clinically stable COPD. BMD and inflammatory markers, including C-reactive protein, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), were determined in all the recruited patients with clinically stable COPD. The patients were classified according to T scores, and the relationship between BMD with markers of systemic inflammation and that with other osteoporosis risk factors was assessed. There were no differences in age, female sex, body composition, tobacco exposure, and the use of respiratory medications among these groups. As the abnormality of BMD went severer, COPD patients with osteoporosis had significantly higher levels of systemic inflammation than those with either normal BMD or osteopenia. The presence of systemic inflammation was associated with a greater likelihood of low BMD, and multivariate logistic regression analysis showed that TNF-α and IL-6 were independent predictors of low BMD. It can be concluded that systemic inflammation is a significantly independent predictor of low BMD in patients with clinically stable COPD.