Metformin use and health care utilization in patients with coexisting chronic obstructive pulmonary disease and diabetes mellitus

Metformin use is associated with decreased asthma exacerbations in adolescents and young adults

RATIONALE

Metformin is a commonly used antidiabetes medication with suggested anti-inflammatory and antioxidative effects. Metformin use has been associated with lower risk of asthma exacerbations and hospitalizations in adults. Here, we aimed to evaluate how asthma exacerbation rates changed after adolescents and young adults were prescribed metformin, and to learn if those changes were related to metformin prescription adherence.

METHODS

Using secondary data of patients between 12 and 20 years old with asthma diagnosis and a metformin prescription from the Arkansas All Payers Claim Database and Arkansas School body mass index (BMI) database, we estimated the change in annualized asthma exacerbation rates after metformin prescription. We also evaluated the association of prescription adherence to the changes in those rates using univariate and multivariate regression models.

RESULTS

A total of 464 patients met inclusion criteria. Outpatient exacerbation rates decreased after metformin prescription (13.4% only before vs. 7.8% only after, p = .009), and the annualized rate decreased more after metformin prescription as adherence increased (rank r = -.165, p < .001). After adjusting for potential confounders-age, sex, BMI, and inhaled corticoid steroid use-the strength of the association was attenuated.

CONCLUSIONS

Asthma exacerbation rates decreased after metformin prescription, but a larger sample of patients who have experienced exacerbations and including patients with asthma who have not been prescribed metformin is needed to better know whether these decreases are driven by metformin use.

Targeting accelerated pulmonary ageing to treat chronic obstructive pulmonary disease-induced neuropathological comorbidities

Chronic obstructive pulmonary disease (COPD) is a major incurable health burden, ranking as the third leading cause of death worldwide, mainly driven by cigarette smoking. COPD is characterised by persistent airway inflammation, lung function decline and premature ageing with the presence of pulmonary senescent cells. This review proposes that cellular senescence, a state of stable cell cycle arrest linked to ageing, induced by inflammation and oxidative stress in COPD, extends beyond the lungs and affects the systemic circulation. This pulmonary senescent profile will reach other organs via extracellular vesicles contributing to brain inflammation and damage, and increasing the risk of neurological comorbidities, such as stroke, cerebral small vessel disease and Alzheimer's disease. The review explores the role of cellular senescence in COPD-associated brain conditions and investigates the relationship between cellular senescence and circadian rhythm in COPD. Additionally, it discusses potential therapies, including senomorphic and senolytic treatments, as novel strategies to halt or improve the progression of COPD.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.

Effects and safety of metformin in patients with concurrent diabetes mellitus and chronic obstructive pulmonary disease: a systematic review and meta-analysis

Aim

This study aimed to investigate the effects and safety of metformin in patients with concurrent diabetes mellitus (DM) and chronic obstructive pulmonary disease (COPD).

Methods

PubMed, Embase, Web of Science, the China National Knowledge, and Cochrane Database were searched to find studies that examined the effects and safety of metformin in patients with concurrent DM and COPD. We conducted a meta-analysis with a risk ratio (RR) and assessed the quality of included studies and pooled evidence.

Results

Eight studies were involved. Metformin was associated with lower risk of COPD-related hospitalizations (RR: 0.72, 95% CI: 0.53-0.98; I2= 89%) and all-cause mortality (RR: 0.60, 95% CI: 0.36-1.01, I2= 69%) in patients with concurrent DM and COPD, but did not increase the risk of hyperlactatemia (RR: 1.14, 95% CI: 0.92-1.41, I2 = 8%).

Conclusions

Metformin use is associated with lower risk of COPD-related hospitalizations and risk of all-cause mortality without increasing the risk of hyperlactatemia. Considerations should be given to conduct more high-quality randomized trials involving larger samples.

Enhanced Risk of Osteoporotic Fracture in Patients with Sarcopenia: A National Population-Based Study in Taiwan

Sarcopenia is a progressive and generalized skeletal muscle disorder associated with poor health outcomes in older adults. However, its association with the risk of fracture risk is yet to be clarified. Therefore, this study aimed to assess the incidence and consequence of osteoporosis-related fractures among patients with sarcopenia in Taiwan. A retrospective, population-based study on 616 patients with sarcopenia, aged >40 years, and 1232 individuals without sarcopenia was conducted to evaluate claims data from Taiwan’s National Health Insurance Research Database collected in the period January 2000−December 2013. The incidence rate of osteoporosis-related fracture was 18.13 and 14.61 per 1000 person years in the patients with sarcopenia and comparison cohort, respectively. Patients with sarcopenia had a greater osteoporotic fracture risk (adjusted hazard ratio [HR] 2.11; 95% confidence interval [CI] 1.47−3.04) after correcting for possible confounding. Additionally, females showed statistically significant correlations of sarcopenia with osteoporosis-related fracture risk (HR 1.53; CI 0.83−2.8 for males and HR 2.40, CI 1.51−3.81 for females). During this retrospective study on the fracture risk in Taiwan, an adverse impact of sarcopenia was observed, which substantiates the need to work toward sarcopenia prevention and interventions to reverse fracture susceptibility in patients with sarcopenia.

COPD and diabetes mellitus: down the rabbit hole

Abstract:

: One of the important comorbidities that has a longstanding research history in COPD is diabetes. Although there are multiple studies on COPD and diabetes the exact links between these two conditions is still controversial. The exact prevalence of diabetes in COPD varies between 2 and 37 %. The true nature of this relationship is complex and may be partially related to the traditional risk factors for diabetes such as smoking, cardiovascular disease and use of steroids. However, COPD is a disease that has multiple phenotypes and is no longer regarded as a homogeneous condition. It seems that some COPD patients who have overlap with asthma or the obese phenotype at a particular risk for T2DM. The aim of this review is to analyze the prevalence, risk factors and possible interactions between COPD and diabetes mellitus.

Identifying COPD in routinely collected electronic health records: a systematic scoping review

Although routinely collected electronic health records (EHRs) are widely used to examine outcomes related to COPD, consensus regarding the identification of cases from electronic healthcare databases is lacking. We systematically examine and summarise approaches from the recent literature. MEDLINE via EBSCOhost was searched for COPD-related studies using EHRs published from January 1, 2018 to November 30, 2019. Data were extracted relating to the case definition of COPD and determination of COPD severity and phenotypes. From 185 eligible studies, we found widespread variation in the definitions used to identify people with COPD in terms of code sets used (with 20 different code sets in use based on the ICD-10 classification alone) and requirement of additional criteria (relating to age (n=139), medication (n=31), multiplicity of events (n=21), spirometry (n=19) and smoking status (n=9)). Only seven studies used a case definition which had been validated against a reference standard in the same dataset. Various proxies of disease severity were used since spirometry results and patient-reported outcomes were not often available. To enable the research community to draw reliable insights from EHRs and aid comparability between studies, clear reporting and greater consistency of the definitions used to identify COPD and related outcome measures is key.

Combination therapies with thiazolidinediones are associated with a lower risk of acute exacerbations in new-onset COPD patients with advanced diabetic mellitus: a cohort-based case-control study

BACKGROUND

The effects of oral antihyperglycaemic drugs (OADs) for type 2 diabetes mellitus (T2DM) on the outcomes of co-existing chronic obstructive pulmonary disease (COPD) patients are not well studied. We examined the association of combinational OADs and the risk of acute exacerbations of COPD (AECOPD) in T2DM patients with co-existing COPD.

METHODS

A cohort-based case-control study was conducted using data from the National Health Insurance Research Database of Taiwan. Among new-onset COPD-T2DM patients, 65,370 were prescribed metformin and 2nd-line OADs before the date of COPD onset. Each AECOPD case was matched to 4 randomly selected controls according to the propensity score estimated by the patient's baseline characteristics. Conditional logistic regression analysis was performed to estimate the association between AECOPD risk and OAD use.

RESULTS

Among COPD-T2DM patients, 3355 AECOPD cases and 13,420 matched controls were selected. Of the patients treated with a double combination of oral OADs (n = 12,916), those treated with sulfonylurea (SU) and thiazolidinediones (TZD) had a lower AECOPD risk than the patients who received metformin (MET) and SU, with an adjusted odds ratio (OR) of 0.69 (95% confidence interval [CI] 0.51-0.94, P = 0.02). Of the patients with a triple combination of oral OADs (n = 3859), we found that those treated with MET, SU and TZD had a lower risk of AECOPD (adjusted OR 0.81 (0.68-0.96, P = 0.01) than a combination of MET, SU and α-glucosidase inhibitors (AGIs) regardless of the level of COPD complexity.

CONCLUSION

Combination therapies with TZD were associated with a reduced risk of AECOPD in advanced T2DM patients with co-existing COPD.

Glycated Hemoglobin (HbA1c) as a Predictor of Outcomes during Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Systemic inflammation may be the common denominator between COPD and type 2 diabetes and may explain the correlation in both diseases' development and progress. The aim of this prospective observational study is to examine the prognostic value of glycated hemoglobin levels (HbA1c) and HbA1c-adjusted glycemic variables (glycemic gap, stress hyperglycemia ratio και modified stress hyperglycemia ratio) in an acute exacerbation of COPD (AECOPD) as well as in COPD disease's morbidity and mortality during the following year. We evaluated patients hospitalized only for COPD exacerbations. Levels of HbA1c and HbA1c-adjusted glycemic variables were recorded upon admission. The study outcomes included duration of hospital stay, need for mechanical ventilation and exacerbation outcome. All subjects were followed up for one year. A total of 156 patients were included in the study (74.4% men, age [mean ± SD] 72 ± 7 years). Patients (21.8%) had type 2 diabetes and 67.9% of patients were receiving ICS treatment. The median value of HbA1c was 5.9 (IQR: 5.4, 6.5). Necessity for mechanical ventilation was significantly higher for patients with lower values of HbA1c [median: 5.3 (IQR 5.02, 6.3) vs. 5.9 (IQR 5.5, 6.5), p = .038]. However, duration of hospitalization, death during hospitalization as well as the number of new exacerbation events, time to next exacerbation and mortality during the following year did not differ significantly. Moreover, none of the HbA1c-adjusted glycemic variables examined, demonstrated any statistical significance. In conclusion neither the preceding nor the present glycemic state exhibit a predictive value regarding short- or long-term outcomes of an AECOPD.

Use of antidiabetic medications and risk of chronic obstructive pulmonary disease exacerbation requiring hospitalization: a disease risk score-matched nested case-control study

BACKGROUND

Exacerbation of chronic obstructive pulmonary disease (COPD) severely impacts the quality of life and causes high mortality and morbidity. COPD is involved with systemic and pulmonary inflammation, which may be attenuated with antidiabetic agents exerting anti-inflammatory effects. Real-world evidence is scant regarding the effects of antidiabetic agents on COPD exacerbation. Accordingly, we conducted a disease risk score (DRS)-matched nested case-control study to systemically assess the association between each class of oral hypoglycemic agents (OHAs) and risk of severe COPD exacerbation in a nationwide COPD population co-diagnosed with diabetes mellitus (DM).

METHODS

We enrolled 23,875 COPD patients receiving at least one OHA for management of DM by analyzing the Taiwan National Health Insurance claims database between January 1, 2000, and December 31, 2015. Cases of severe exacerbation were defined as those who had the first hospital admission for COPD. Each case was individually matched with four randomly-selected controls by cohort entry date, DRS (the estimated probability of encountering a severe COPD exacerbation), and COPD medication regimens using the incidence density sampling approach. Conditional logistic regressions were performed to estimate odds ratios (OR) of severe COPD exacerbation for each type of OHAs.

RESULTS

We analyzed 2700 cases of severe COPD exacerbation and 9272 corresponding controls after DRS matching. Current use of metformin versus other OHAs was associated with a 15% (adjusted OR [aOR], 0.85; 95% confidence interval [CI] 0.75-0.95) reduced risk of severe COPD exacerbation, whereas the reduced risk was not observed with other types of antidiabetic agents. When considering the duration of antidiabetic medication therapy, current use of metformin for 91-180 and 181-365 days was associated with a 28% (aOR, 0.72; 95% CI 0.58-0.89) and 37% (aOR, 0.63; 95% CI 0.51-0.77) reduced risk of severe COPD exacerbation, respectively. Similarly, 91-180 days of sulfonylureas therapy led to a 28% (aOR, 0.72; 95% CI 0.58-0.90) lower risk, and longer treatments consistently yielded 24-30% lower risks. Current use of thiazolidinediones for more than 181 days yielded an approximately 40% decreased risk.

CONCLUSIONS

Duration-dependent beneficial effects of current metformin, sulfonylurea, and thiazolidinedione use on severe COPD exacerbation were observed in patients with COPD and DM.

Targeting Aging Pathways in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) has become a global epidemic and is the third leading cause of death worldwide. COPD is characterized by chronic airway inflammation, loss of alveolar-capillary units, and progressive decline in lung function. Major risk factors for COPD are cigarette smoking and aging. COPD-associated pathomechanisms include multiple aging pathways such as telomere attrition, epigenetic alterations, altered nutrient sensing, mitochondrial dysfunction, cell senescence, stem cell exhaustion and chronic inflammation. In this review, we will highlight the current literature that focuses on the role of age and aging-associated signaling pathways as well as their impact on current treatment strategies in the pathogenesis of COPD. Furthermore, we will discuss established and experimental COPD treatments including senolytic and anti-aging therapies and their potential use as novel treatment strategies in COPD.

Identification and validation of metformin protects against PM2.5-induced macrophages cytotoxicity by targeting toll like receptor pathway

Fine particle matter (PM_2.5) has been extensively reported to contribute to the pathogenesis of pulmonary diseases. Recently, metformin has been reported to attenuate PM_2.5 associated respiratory and cardiovascular injury, but the underling mechanism has not been discovered. Here, we performed comprehensively bioinformatics analysis and fully validation experiment to investigate the protection role of metformin and underling mechanism with RNAseq profile in GEO database. A combination of various bioinformatics tools including edgeR, principal component analysis (PCA), K-Means clustering, Gene Set Enrichment Analysis (GSEA), GO and KEGG enrichment were performed to identify the TLRs/MyD88/NF-κB axis functional as the key signaling transduction during PM_2.5 associated toxicity. PM_2.5 activated TLRs/MyD88/NF-κB pathway and resulted in significantly generation of IL-6, TNF-α, mitochondrial damage, decreasing of cell viability and increased LDH activity in RAW264.7 cells. Metformin significantly attenuated the production of IL-6, mitochondrial damage, cell viability and LDH activity by limiting TLRs/MyD88/NF-κB pathway. The siRNA against AMPKα2 or negative control were transfected to RAW264.7 cells to identify whether metformin protects PM_2.5-induced cytotoxicity in an AMPKα2-dependent manner. Pretreatment with metformin significantly attenuated PM_2.5 induced decreasing of cell viability and increased LDH activity, as well as inhibited the TLRs/MyD88/NF-κB pathway in both siControl or siAMPKα2 cells. Taken together, our results indicate that metformin protects against PM_2.5-induced mitochondrial damage and cell cytotoxicity by inhibiting TLRs/MyD88/NF-κB signaling pathway in an AMPKα2 independent manner.

Respiratory outcomes of metformin use in patients with type 2 diabetes and chronic obstructive pulmonary disease

Few studies investigated the respiratory outcomes of metformin use in patients with coexistent type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD). We want to compare the long-term respiratory endpoints of metformin use and nonuse in patients with T2DM and COPD. This retrospective cohort study enrolled patients with T2DM and COPD from Taiwan’s National Health Insurance Program between January 1, 2000, and December 31, 2012. Main outcomes were hospitalized bacterial pneumonia, hospitalization for COPD, noninvasive positive pressure ventilation (NIPPV), invasive mechanical ventilation (IMV), and lung cancer. In total, 20,644 propensity score-matched metformin users and nonusers were assessed. The adjusted hazard ratios (95% confidence intervals) of metformin use relative to nonuse for bacterial pneumonia, hospitalization for COPD, NIPPV, IMV, and lung cancer were 1.17 (1.11–1.23), 1.34 (1.26–1.43), 0.99 (0.89–1.10), 1.10 (1.03–1.17), and 1.12 (0.96–1.30). Metformin use also exhibited significant dose–response relationship with respect to the risks of bacterial pneumonia, hospitalization for COPD and IMV. Consistent results were found in the sensitivity test. This nationwide cohort study demonstrated that in patients with T2DM and COPD, metformin use was associated with higher risks of pneumonia, hospitalization for COPD, and IMV. If patients with COPD use metformin, vigilance with regard to their pulmonary condition may be required.

Recent Advances in Molecular Basis of Lung Aging and Its Associated Diseases

Aging is often viewed as a progressive decline in fitness due to cumulative deleterious alterations of biological functions in the living system. Recently, our understanding of the molecular mechanisms underlying aging biology has significantly advanced. Interestingly, many of the pivotal molecular features of aging biology are also found to contribute to the pathogenesis of chronic lung disorders such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis, for which advanced age is the most crucial risk factor. Thus, an enhanced understanding of how molecular features of aging biology are intertwined with the pathobiology of these aging-related lung disorders has paramount significance and may provide an opportunity for the development of novel therapeutics for these major unmet medical needs. To serve the purpose of integrating molecular understanding of aging biology with pulmonary medicine, in this review, recent findings obtained from the studies of aging-associated lung disorders are summarized and interpreted through the perspective of molecular biology of aging.

Diabetes Mellitus and Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disease with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Apart from cigarette smoking, certain occupational and environmental exposures, low socioeconomic status and genetic factors may contribute to the pathogenesis of COPD. Comorbidities, e. g. diabetes mellitus (DM), can negatively affect quality of life, COPD outcomes and cardiovascular risk. The present narrative review considers the potential links between COPD and DM, such as systemic inflammation, oxidative stress, hypoxaemia and hyperglycaemia. The effects of antidiabetic drugs on lung function and COPD outcomes, as well as the possibility of common therapeutic modalities are also briefly considered. Further research is needed in this field to elucidate these relationships as well as their potential clinical implications in daily practice.

Diabetic lung disease: fact or fiction?

Diabetes mellitus is a chronic, progressive, incompletely understood metabolic disorder whose prevalence has been increasing steadily worldwide. Even though little attention has been paid to lung disorders in the context of diabetes, its prevalence has recently been challenged by newer studies of disease development. In this review, we summarize and discuss the role of diabetes mellitus involved in the progression of pulmonary diseases, with the main focus on pulmonary fibrosis, which represents a chronic and progressive disease with high mortality and limited therapeutic options.

Reduced mortality from lower respiratory tract disease in adult diabetic patients treated with metformin

BACKGROUND AND OBJECTIVE

Chronic lower respiratory diseases (CLRD) increase the risk of type 2 diabetes, which in turn may worsen lung function. Metformin, a common antidiabetic with anti-inflammatory and antioxidant properties, may improve respiratory outcomes. Therefore, we examined the association of metformin use with the risk of mortality from CLRD.

METHODS

We analysed data from the National Health and Nutrition Examination Survey during 1988-1994 and 1999-2010 for participants aged 40 years or older who had diabetes and were followed up for mortality through 2011. Information on prescription medicine was collected at baseline and CLRD-related mortality during follow-up was defined using the 10th Revision of the International Classification of Diseases (ICD-10). Cox proportional hazards modelling was used to determine the mortality hazard ratio (HR) associated with metformin use, adjusting for relevant covariates.

RESULTS

A total of 5266 participants with a median follow-up of 6.1 years were included. The prevalence of metformin use was 31.9% and 1869 participants died during follow-up, including 72 of CLRD. In the adjusted Cox proportional regression analysis, metformin was associated with a decreased risk of CLRD mortality in the overall population (HR: 0.39, 95% CI: 0.15-0.99) and among participants with baseline CLRD (HR: 0.30, 95% CI: 0.10-0.93), after adjusting for age, gender, race/ethnicity, cigarette smoking, body mass index, current asthma and chronic obstructive pulmonary disease (COPD), insulin and other diabetic medications, and glycohaemoglobin level. We found no association between other antidiabetic medications and CLRD mortality.

CONCLUSION

In this sample representative of the U.S. population, metformin was associated with lower CLRD mortality in adults with diabetes.

Long-term observational study on the impact of GLP-1R agonists on lung function in diabetic patients

INTRODUCTION

Preclinical research suggests a role of Glucagon Like Peptide-1 Receptors (GLP-1R) on the regulation of human bronchial tone. We investigated the effect of GLP-1R agonists on lung function of Type 2 Diabetes Mellitus (T2DM) population without co-existing chronic obstructive respiratory disorders.

METHODS

This was a prospective cohort study that examined change in lung function measurements over two years of T2DM patients (n = 32) treated with metformin monotherapy (control cohort), metformin plus GLP-1R agonists (GLP-1R agonists cohort), or metformin plus insulin (insulin cohort).

RESULTS

After 24 months of treatment, the forced expiratory volume in 1 s (FEV₁) significantly (p < 0.05) increased from baseline in the GLP-1R agonists cohort (218 ml [95%CI 88-246]), but not in the control and insulin cohorts (94 ml [95%CI -28 - 216] and 26 ml [95%CI -174 - 226], respectively; p > 0.05 vs. baseline). The average increase in FEV₁ in the GLP-1R agonists cohort was significantly greater than that in the control and insulin cohorts (delta: 110 ml [95%CI 18-202] and 177 ml [95%CI 85-270], respectively, p < 0.05). The forced vital capacity (FVC) also increased significantly more in the GLP-1R agonists cohort than in the control and insulin cohorts (overall delta FVC: 183 ml [95%CI 72-295], p < 0.05). The maximal expiratory flow at 50-75% significantly (p < 0.05) improved from baseline in the GLP-1R agonists cohort, but not in the control and insulin cohorts (p > 0.05).

CONCLUSION

Our preliminary results suggest a potential new therapeutic perspective to treat airway disorders with GLP-1R agonists.

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.

Accelerated lung aging and chronic obstructive pulmonary disease

INTRODUCTION

The prevalence of chronic obstructive pulmonary disease (COPD) increases exponentially with aging. Its pathogenesis, however, is not well known and aside from smoking cessation, there are no disease-modifying treatments for this disease. Areas covered: COPD is associated with accelerating aging and aging-related diseases. In this review, we will discuss the hallmarks of aging including genomic instability, telomere attrition, epigenetic alteration, loss of proteostasis, mitochondrial dysfunction, deregulated nutrient sensing, cellular senescence, stem cell exhaustion, and altered intercellular communication, which may be involved in COPD pathogenesis. Expert commentary: COPD and the aging process share similar molecular and cellular changes. Aging-related molecular pathways may represent novel therapeutic targets and biomarkers for COPD.

Metformin inhibits IgE- and aryl hydrocarbon receptor-mediated mast cell activation in vitro and in vivo

Metformin, an anti-diabetic drug, possesses anti-inflammatory property beyond its glucose-lowering activity, but its regulatory effect on mast cells and allergic responses remains unknown, wherein the aryl hydrocarbon receptor (AhR)-ligand axis is critical in controlling mast cell activation. Herein, we provide evidence supporting the role of metformin in modulating mast cell activation by FcεR1-, AhR-mediated signaling or their combination. Metformin at relatively low doses was shown to suppress FcεR1-mediated degranulation, IL-13, TNF-α and sphingosine-1-phosphate (S1P) secretion in murine bone marrow-derived mast cells (BMMCs). In contrast, metformin at the same doses potently inhibited all parameters in mast cells stimulated with an AhR ligand, 5,11-dihydroindolo[3,2-b]carbazole-6-carbaldehyde (FICZ). Further, metformin was shown to inhibit FcεR1- and AhR-mediated passive cutaneous anaphylaxis (PCA) in vivo, reversible by a S1P receptor 2 antagonist, JTE-013. Using AhR reporter cells, Huh7-DRE-Luc cells, a human mast cell line, HMC-1, and BMMCs, metformin's inhibitory effect was mediated through the suppression of FICZ-induced AhR activity, calcium mobilization and ROS generation. Notably, FICZ-mediated oxidation of S1P lyase (S1PL) and its reduced activity were reversed by metformin, resulting in decreased levels of S1P. Collectively, these results suggested the potential utility of metformin in treating allergic diseases, particularly in cases with comorbid type II diabetes mellitus.

Relationship between diabetes and respiratory diseases-Clinical and therapeutic aspects

Diabetes is a common metabolic disorder affecting the entire body with high morbidity and mortality worldwide. The major complications related to diabetes are mostly due to the macrovascular and microvascular bed impairment due to metabolic, hemodynamic and inflammatory factors. However, studies over the past decades have added also the lung as a target organ in both type 1 and type 2 diabetes. Diabetes has always been addressed as a major comorbidity conditioning the disease behaviour and the natural history of several respiratory diseases. Increased interest has recently focused on the pathophysiology of the metabolic glycaemic disorder and the respiratory diseases suggesting a similar background shared by the two conditions. The true relationship between pulmonary diseases and diabetes mellitus has not been clarified, this review aims to summarize the link between diabetes and coexisting respiratory diseases such as asthma, chronic obstructive pulmonary disease, respiratory infections, cystic fibrosis, lung cancer and obstructive sleep apnea from a pathogenetic and therapeutic point of view.