Metformin in severe exacerbations of chronic obstructive pulmonary disease: a randomised controlled trial

Genetic variations in anti-diabetic drug targets and COPD risk: evidence from mendelian randomization

BACKGROUND

Previous research has emphasized the potential benefits of anti-diabetic medications in inhibiting the exacerbation of Chronic Obstructive Pulmonary Disease (COPD), yet the role of anti-diabetic drugs on COPD risk remains uncertain.

METHODS

This study employed a Mendelian randomization (MR) approach to evaluate the causal association of genetic variations related to six classes of anti-diabetic drug targets with COPD. The primary outcome for COPD was obtained from the Global Biobank Meta-analysis Initiative (GBMI) consortium, encompassing a meta-analysis of 12 cohorts with 81,568 cases and 1,310,798 controls. Summary-level data for HbA1c was derived from the UK Biobank, involving 344,182 individuals. Positive control analysis was conducted for Type 2 Diabetes Mellitus (T2DM) to validate the choice of instrumental variables. The study applied Summary-data-based MR (SMR) and two-sample MR for effect estimation and further adopted colocalization analysis to verify evidence of genetic variations.

RESULTS

SMR analysis revealed that elevated KCNJ11 gene expression levels in blood correlated with reduced COPD risk (OR = 0.87, 95% CI = 0.79-0.95; p = 0.002), whereas an increase in DPP4 expression corresponded with an increased COPD incidence (OR = 1.18, 95% CI = 1.03-1.35; p = 0.022). Additionally, the primary method within MR analysis demonstrated a positive correlation between PPARG-mediated HbA1c and both FEV1 (OR = 1.07, 95% CI = 1.02-1.13; P = 0.013) and FEV1/FVC (OR = 1.08, 95% CI = 1.01-1.14; P = 0.007), and a negative association between SLC5A2-mediated HbA1c and FEV1/FVC (OR = 0.86, 95% CI = 0.74-1.00; P = 0.045). No colocalization evidence with outcome phenotypes was detected (all PP.H4 < 0.7).

CONCLUSION

This study provides suggestive evidence for anti-diabetic medications' role in improving COPD and lung function. Further updated MR analyses are warranted in the future, following the acquisition of more extensive and comprehensive data, to validate our results.

Anti-Inflammatory Potential of the Anti-Diabetic Drug Metformin in the Prevention of Inflammatory Complications and Infectious Diseases Including COVID-19: A Narrative Review

Metformin, a widely used first-line anti-diabetic therapy for the treatment of type-2 diabetes, has been shown to lower hyperglycemia levels in the blood by enhancing insulin actions. For several decades this drug has been used globally to successfully control hyperglycemia. Lactic acidosis has been shown to be a major adverse effect of metformin in some type-2 diabetic patients, but several studies suggest that it is a typically well-tolerated and safe drug in most patients. Further, recent studies also indicate its potential to reduce the symptoms associated with various inflammatory complications and infectious diseases including coronavirus disease 2019 (COVID-19). These studies suggest that besides diabetes, metformin could be used as an adjuvant drug to control inflammatory and infectious diseases. In this article, we discuss the current understanding of the role of the anti-diabetic drug metformin in the prevention of various inflammatory complications and infectious diseases in both diabetics and non-diabetics.

Association of Novel Antihyperglycemic Drugs Versus Metformin With a Decrease in Asthma Exacerbations

BACKGROUND

Similar to metformin, dipeptidyl peptidase-4 inhibitors (DPP-4 Is), glucagon-like peptidase 1 receptor agonists (GLP-1 RAs), and sodium glucose co-transporter-2 inhibitors (SGLT-2 Is) may improve control of asthma owing to their multiple potential mechanisms, including differential improvements in glycemic control, direct anti-inflammatory effects, and systemic changes in metabolism.

OBJECTIVE

To investigate whether these novel antihyperglycemic drugs were associated with fewer asthma exacerbations compared with metformin in patients with asthma comorbid with type 2 diabetes.

METHODS

Using a Japanese national administrative database, we constructed 3 active comparators-new user cohorts of 137,173 patients with a history of asthma starting the novel antihyperglycemic drugs and metformin between 2014 and 2022. Patient characteristics were balanced using overlap propensity score weighting. The primary outcome was the first exacerbation requiring systemic corticosteroids, and the secondary outcomes included the number of exacerbations requiring systemic corticosteroids.

RESULTS

DPP-4 Is and GLP-1 RAs were associated with a higher incidence of exacerbations requiring systemic corticosteroids compared with metformin (DPP-4 Is: 18.2 vs 17.4 per 100 person-years, hazard ratio: 1.09, 95% confidence interval [CI]: 1.05-1.14; GLP-1 RAs: 24.9 vs 19.0 per 100 person-years, hazard ratio: 1.14, 95% CI: 1.01-1.28). In contrast, the incidence of exacerbations requiring systemic corticosteroids was similar between the SGLT-2 Is and metformin groups (17.3 vs 18.1 per 100 person-years, hazard ratio: 1.00, 95% CI: 0.97-1.03). While DPP-4 Is and GLP-1 RAs were associated with more exacerbations requiring systemic corticosteroids, SGLT-2 Is were associated with slightly fewer exacerbations requiring systemic corticosteroids (53.7 vs 56.6 per 100 person-years, rate ratio: 0.95, 95% CI: 0.91-0.99).

CONCLUSIONS

While DPP-4 Is and GLP-1 RAs were associated with poorer control of asthma compared with metformin, SGLT-2 Is offered asthma control comparable to that of metformin.

Preclinical evidence using synthetic compounds and natural products indicates that AMPK represents a potential pharmacological target for the therapy of pulmonary diseases

Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a highly conserved eukaryotic enzyme discovered as a key regulator of cellular energy homeostasis, with anti-inflammation, antioxidative stress, anticancer, and antifibrosis beneficial effects. AMPK is dysregulated in human pulmonary diseases such as acute lung injury, nonsmall cell lung cancer, pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. This review provides an overview of the beneficial role of natural, synthetic, and Chinese traditional medicines AMPK modulators in pulmonary diseases, and highlights the role of the AMPK signaling pathway in the lung, emphasizing the importance of finding lead compounds and drugs that can target and modulate AMPK to treat the lung diseases.

Treatment of glucocorticoid- induced hyperglycemia in hospitalized patients - a systematic review and meta- analysis

PURPOSE

Glucocorticoid (GC)-induced hyperglycemia is a frequent issue, however there are no specific guidelines for this diabetes subtype. Although treat-to-target insulin is recommended in general to correct hyperglycemia, it remains unclear which treatment strategy has a positive effect on outcomes. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess whether treating GC-induced hyperglycemia improves clinical outcomes.

METHODS

MEDLINE and EMBASE were systematically searched for RCTs on adults reporting treatment and outcomes of GC-induced hyperglycemia since the beginning of the data bases until October 21, 2023. Glucose-lowering strategies as compared to usual care were investigated.

RESULTS

We found 17 RCTs with 808 patients and included seven trials in the quantitative analysis. Patients with an intensive glucose-lowering strategy had lower standardized mean glucose levels of - 0.29 mmol/l (95%CI -0.64 to -0.05) compared to usual care group patients. There was no increase in hypoglycemic events in the intensively treated groups (RR 0.91, 95%CI 0.70-1.17). Overall, we did not have enough trials reporting clinical outcomes for a quantitative analysis with only one trial reporting mortality.

CONCLUSION

In GC-induced hyperglycemia, tight glucose control has a moderate effect on mean glucose levels with no apparent harmful effect regarding hypoglycemia. There is insufficient data whether insulin treatment improves clinical outcomes, and data on non-insulin based treatment regimens are currently too sparse to draw any conclusions.

SYSTEMATIC REVIEW REGISTRATION

Registered as CRD42020147409 at PROSPERO ( https://www.crd.york.ac.uk/prospero/ ) on April 28, 2020.

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.

Hyperglycaemia and Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) may coexist with type 2 diabetes mellitus (T2DM). Patients with COPD have an increased risk of developing T2DM compared with a control but, on the other side, hyperglycaemia and DM have been associated with reduced predicted levels of lung function. The mechanistic relationships between these two diseases are complicated, multifaceted, and little understood, yet they can impact treatment strategy. The potential risks and benefits for patients with T2DM treated with pulmonary drugs and the potential pulmonary risks and benefits for patients with COPD when taking antidiabetic drugs should always be considered. The interaction between the presence and/or treatment of COPD, risk of infection, presence and/or treatment of T2DM and risk of acute exacerbations of COPD (AECOPDs) can be represented as a vicious circle; however, several strategies may help to break this circle. The most effective approach to simultaneously treating T2DM and COPD is to interfere with the shared inflammatory substrate, thus targeting both lung inflammation (COPD) and vascular inflammation (DM). In any case, it is always crucial to establish glycaemic management since the reduction in lung function found in people with diabetes might decrease the threshold for clinical manifestations of COPD. In this article, we examine possible connections between COPD and T2DM as well as pharmacological strategies that could focus on these connections.

COPD and multimorbidity: recognising and addressing a syndemic occurrence

Most patients with chronic obstructive pulmonary disease (COPD) have at least one additional, clinically relevant chronic disease. Those with the most severe airflow obstruction will die from respiratory failure, but most patients with COPD die from non-respiratory disorders, particularly cardiovascular diseases and cancer. As many chronic diseases have shared risk factors (eg, ageing, smoking, pollution, inactivity, and poverty), we argue that a shift from the current paradigm in which COPD is considered as a single disease with comorbidities, to one in which COPD is considered as part of a multimorbid state-with co-occurring diseases potentially sharing pathobiological mechanisms-is needed to advance disease prevention, diagnosis, and management. The term syndemics is used to describe the co-occurrence of diseases with shared mechanisms and risk factors, a novel concept that we propose helps to explain the clustering of certain morbidities in patients diagnosed with COPD. A syndemics approach to understanding COPD could have important clinical implications, in which the complex disease presentations in these patients are addressed through proactive diagnosis, assessment of severity, and integrated management of the COPD multimorbid state, with a patient-centred rather than a single-disease approach.

Current and future developments in the pharmacology of asthma and COPD: ERS seminar, Naples 2022

Pharmacological management of airway obstructive diseases is a fast-evolving field. Several advances in unravelling disease mechanisms as well as intracellular and molecular pathways of drug action have been accomplished. While the clinical translation and implementation of in vitro results to the bedside remains challenging, advances in comprehending the mechanisms of respiratory medication are expected to assist clinicians and scientists in identifying meaningful read-outs and designing clinical studies. This European Respiratory Society Research Seminar, held in Naples, Italy, 5-6 May 2022, focused on current and future developments of the drugs used to treat asthma and COPD; on mechanisms of drug action, steroid resistance, comorbidities and drug interactions; on prognostic and therapeutic biomarkers; on developing novel drug targets based on tissue remodelling and regeneration; and on pharmacogenomics and emerging biosimilars. Related European Medicines Agency regulations are also discussed, as well as the seminar's position on the above aspects.

Senotherapy for lung diseases

Increasing evidence suggests that there is acceleration of lung ageing in chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), with the accumulation of senescent cells in the lung. Senescent cells fail to repair tissue damage and release an array of inflammatory proteins, known as the senescence-associated secretory phenotype, which drive further senescence and disease progression. This suggests that targeting cellular senescence with senotherapies may treat the underlying disease process in COPD and IPF and thus reduce disease progression and mortality. Several existing or future drugs may inhibit the development of cellular senescence which is driven by chronic oxidative stress (senostatics), including inhibitors of PI3K-mTOR signalling pathways, antagomirs of critical microRNAs and novel antioxidants. Other drugs (senolytics) selectively remove senescent cells by promoting apoptosis. Clinical studies with senotherapies are already underway in chronic lung diseases.

Drugs against metabolic diseases as potential senotherapeutics for aging-related respiratory diseases

Recent advances in aging research have provided novel insights for the development of senotherapy, which utilizes cellular senescence as a therapeutic target. Cellular senescence is involved in the pathogenesis of various chronic diseases, including metabolic and respiratory diseases. Senotherapy is a potential therapeutic strategy for aging-related pathologies. Senotherapy can be classified into senolytics (induce cell death in senescent cells) and senomorphics (ameliorate the adverse effects of senescent cells represented by the senescence-associated secretory phenotype). Although the precise mechanism has not been elucidated, various drugs against metabolic diseases may function as senotherapeutics, which has piqued the interest of the scientific community. Cellular senescence is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), which are aging-related respiratory diseases. Large-scale observational studies have reported that several drugs, such as metformin and statins, may ameliorate the progression of COPD and IPF. Recent studies have reported that drugs against metabolic diseases may exert a pharmacological effect on aging-related respiratory diseases that can be different from their original effect on metabolic diseases. However, high non-physiological concentrations are needed to determine the efficacy of these drugs under experimental conditions. Inhalation therapy may increase the local concentration of drugs in the lungs without exerting systemic adverse effects. Thus, the clinical application of drugs against metabolic diseases, especially through an inhalation treatment modality, can be a novel therapeutic approach for aging-related respiratory diseases. This review summarizes and discusses accumulating evidence on the mechanisms of aging, as well as on cellular senescence and senotherapeutics, including drugs against metabolic diseases. We propose a developmental strategy for a senotherapeutic approach for aging-related respiratory diseases with a special focus on COPD and IPF.

Role of cellular senescence in inflammatory lung diseases

Cellular senescence, a characteristic sign of aging, classically refers to permanent cell proliferation arrest and is a vital contributor to the pathogenesis of cancer and age-related illnesses. A lot of imperative scientific research has shown that senescent cell aggregation and the release of senescence-associated secretory phenotype (SASP) components can cause lung inflammatory diseases as well. In this study, the most recent scientific progress on cellular senescence and phenotypes was reviewed, including their impact on lung inflammation and the contributions of these findings to understanding the underlying mechanisms and clinical relevance of cell and developmental biology. Within a dozen pro-senescent stimuli, the irreparable DNA damage, oxidative stress, and telomere erosion are all crucial in the long-term accumulation of senescent cells, resulting in sustained inflammatory stress activation in the respiratory system. An emerging role for cellular senescence in inflammatory lung diseases was proposed in this review, followed by the identification of the main ambiguities, thus further understanding this event and the potential to control cellular senescence and pro-inflammatory response activation. In addition, novel therapeutic strategies for the modulation of cellular senescence that might help to attenuate inflammatory lung conditions and improve disease outcomes were also presented in this research.

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.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

Senescence: Pathogenic Driver in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is recognized as a disease of accelerated lung aging. Over the past two decades, mounting evidence suggests an accumulation of senescent cells within the lungs of patients with COPD that contributes to dysregulated tissue repair and the secretion of multiple inflammatory proteins, termed the senescence-associated secretory phenotype (SASP). Cellular senescence in COPD is linked to telomere dysfunction, DNA damage, and oxidative stress. This review gives an overview of the mechanistic contributions and pathologic consequences of cellular senescence in COPD and discusses potential therapeutic approaches targeting senescence-associated signaling in COPD.

Exaggerated Ventilator-Induced Lung Injury in an Animal Model of Type 2 Diabetes Mellitus: A Randomized Experimental Study

Although ventilator-induced lung injury (VILI) often develops after prolonged mechanical ventilation in normal lungs, pulmonary disorders may aggravate the development of adverse symptoms. VILI exaggeration can be anticipated in type 2 diabetes mellitus (T2DM) due to its adverse pulmonary consequences. Therefore, we determined whether T2DM modulates VILI and evaluated how T2DM therapy affects adverse pulmonary changes. Rats were randomly assigned into the untreated T2DM group receiving low-dose streptozotocin with high-fat diet (T2DM, n = 8), T2DM group supplemented with metformin therapy (MET, n = 8), and control group (CTRL, n = 8). In each animal, VILI was induced by mechanical ventilation for 4 h with high tidal volume (23 ml/kg) and low positive end-expiratory pressure (0 cmH2O). Arterial and venous blood samples were analyzed to measure the arterial partial pressure of oxygen (PaO2), oxygen saturation (SaO2), and the intrapulmonary shunt fraction (Qs/Qt). Airway and respiratory tissue mechanics were evaluated by forced oscillations. Lung histology samples were analyzed to determine injury level. Significant worsening of VILI, in terms of PaO2, SaO2, and Qs/Qt, was observed in the T2DM group, without differences in the respiratory mechanics. These functional changes were also reflected in lung injury score. The MET group showed no difference compared with the CTRL group. Gas exchange impairment without significant mechanical changes suggests that untreated diabetes exaggerates VILI by augmenting the damage of the alveolar–capillary barrier. Controlled hyperglycemia with metformin may reduce the manifestations of respiratory defects during prolonged mechanical ventilation.

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.

Reduced decline of lung diffusing capacity in COPD patients with diabetes and metformin treatment

We studied whether in patients with COPD the use of metformin for diabetes treatment was linked to a pattern of lung function decline consistent with the hypothesis of anti-aging effects of metformin. Patients of GOLD grades 1–4 of the COSYCONET cohort with follow-up data of up to 4.5 y were included. The annual decline in lung function (FEV₁, FVC) and CO diffusing capacity (KCO, TLCO) in %predicted at baseline was evaluated for associations with age, sex, BMI, pack-years, smoking status, baseline lung function, exacerbation risk, respiratory symptoms, cardiac disease, as well as metformin-containing therapy compared to patients without diabetes and metformin. Among 2741 patients, 1541 (mean age 64.4 y, 601 female) fulfilled the inclusion criteria. In the group with metformin treatment vs. non-diabetes the mean annual decline in KCO and TLCO was significantly lower (0.2 vs 2.3, 0.8 vs. 2.8%predicted, respectively; p < 0.05 each), but not the decline of FEV₁ and FVC. These results were confirmed using multiple regression and propensity score analyses. Our findings demonstrate an association between the annual decline of lung diffusing capacity and the intake of metformin in patients with COPD consistent with the hypothesis of anti-aging effects of metformin as reflected in a surrogate marker of emphysema.

Glucose control after glucocorticoid administration in hospitalized patients - a retrospective analysis

BACKGROUND

Glucocorticoid (GC)-induced hyperglycemia is a frequent adverse effect in hospitalized patients. Guidelines recommend insulin treatment to a target range of 6-10 mmol/L (108-180 mg/dl), but efficacies of particular regimes have not been well-studied.

METHODS

In this retrospective cohort study, hospitalized patients receiving GCs at the medical ward were analyzed by treatment (basal-bolus vs. bolus-only vs. pre-mixed insulin) and compared to a non-insulin-therapy reference group. Coefficients of glucose variation (CV), percentage of glucose readings in range (4-10 mmol/L (72-180 mg/dl)) and hypoglycemia (< 4 mmol/L (< 72 mg/dl)) were evaluated.

RESULTS

Of 2424 hospitalized patients receiving systemic GCs, 875 (36%) developed GC-induced hyperglycemia. 427 patients (17%) had a previous diagnosis of diabetes. Adjusted relative risk ratios (RRR) for the top tertile of CV (> 29%) were 1.47 (95% Cl 1.01-2.15) for bolus-only insulin, 4.77 (95% CI 2.67-8.51) for basal-bolus insulin, and 4.98 (95% CI 2.02-12.31) for premixed insulin, respectively. Adjusted RRR for percentages of glucose readings in range were 0.98 (95% Cl 0.97-0.99) for basal-bolus insulin, 0.99 (95% Cl 0.98-1.00) for premixed insulin, and 1.01 (95% Cl 1.00-1.01) for bolus-only insulin, respectively. Adjusted RRR for hypoglycemia was 13.17 (95% Cl 4.35-39.90) for basal-bolus insulin, 8.92 (95% Cl 2.60-30.63) for premixed insulin, and 2.99 (95% Cl 1.01-8.87) for bolus-only insulin, respectively.

CONCLUSIONS

Current guidelines recommend a basal-bolus regimen for treatment of GC-induced hyperglycemia, but we found similar outcomes with pre-mixed and bolus-only insulin regimens. As GC-induced hyperglycemia is a frequent issue in hospitalized patients, it might be reasonable to prospectively study the ideal regimen.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin’s effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin’s adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Unravelling the mechanisms driving multimorbidity in COPD to develop holistic approaches to patient-centred care

COPD is a major cause of morbidity and mortality worldwide. Multimorbidity is common in COPD patients and a key modifiable factor, which requires timely identification and targeted holistic management strategies to improve outcomes and reduce the burden of disease.We discuss the use of integrative approaches, such as cluster analysis and network-based theory, to understand the common and novel pathobiological mechanisms underlying COPD and comorbid disease, which are likely to be key to informing new management strategies.Furthermore, we discuss the current understanding of mechanistic drivers to multimorbidity in COPD, including hypotheses such as multimorbidity as a result of shared common exposure to noxious stimuli (e.g. tobacco smoke), or as a consequence of loss of function following the development of pulmonary disease. In addition, we explore the links to pulmonary disease processes such as systemic overspill of pulmonary inflammation, immune cell priming within the inflamed COPD lung and targeted messengers such as extracellular vesicles as a result of local damage as a cause for multimorbidity in COPD.Finally, we focus on current and new management strategies which may target these underlying mechanisms, with the aim of holistic, patient-centred treatment rather than single disease management.

PI3K signalling in chronic obstructive pulmonary disease and opportunities for therapy

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterised by airway inflammation and progressive obstruction of the lung airflow. Current pharmacological treatments include bronchodilators, alone or in combination with steroids, or other anti-inflammatory agents, which have only partially contributed to the inhibition of disease progression and mortality. Therefore, further research unravelling the underlying mechanisms is necessary to develop new anti-COPD drugs with both lower toxicity and higher efficacy. Extrinsic signalling pathways play crucial roles in COPD development and exacerbations. In particular, phosphoinositide 3-kinase (PI3K) signalling has recently been shown to be a major driver of the COPD phenotype. Therefore, several small-molecule inhibitors have been identified to block the hyperactivation of this signalling pathway in COPD patients, many of them showing promising outcomes in both preclinical animal models of COPD and human clinical trials. In this review, we discuss the critically important roles played by hyperactivated PI3K signalling in the pathogenesis of COPD. We also critically review current therapeutics based on PI3K inhibition, and provide suggestions focusing on PI3K signalling for the further improvement of the COPD phenotype. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Glucagon-Like Peptide 1 Receptor Agonists and Chronic Lower Respiratory Disease Exacerbations Among Patients With Type 2 Diabetes

OBJECTIVE

Emerging data from animal and human pilot studies suggest potential benefits of glucagon-like peptide 1 receptor agonists (GLP-1RA) on lung function. We aimed to assess the association of GLP-1RA and chronic lower respiratory disease (CLRD) exacerbation in a population with comorbid type 2 diabetes (T2D) and CLRD.

RESEARCH DESIGN AND METHODS

A new-user active-comparator analysis was conducted with use of a national claims database of beneficiaries with employer-sponsored health insurance spanning 2005-2017. We included adults with T2D and CLRD who initiated GLP-1RA or dipeptidyl peptidase 4 inhibitors (DPP-4I) as an add-on therapy to their antidiabetes regimen. The primary outcome was time to first hospital admission for CLRD. The secondary outcome was a count of any CLRD exacerbation associated with an inpatient or outpatient visit. We estimated incidence rates using inverse probability of treatment weighting for each study group and compared via risk ratios.

RESULTS

The study sample consisted of 4,150 GLP-1RA and 12,540 DPP-4I new users with comorbid T2D and CLRD. The adjusted incidence rate of first CLRD admission during follow-up was 10.7 and 20.3 per 1,000 person-years for GLP-1RA and DPP-4I users, respectively, resulting in an adjusted hazard ratio of 0.52 (95% CI 0.32-0.85). For the secondary outcome, the adjusted incidence rate ratio was 0.70 (95% CI 0.57-0.87).

CONCLUSIONS

GLP-1RA users had fewer CLRD exacerbations in comparison with DPP-4I users. Considering both plausible mechanistic pathways and this real-world evidence, potential beneficial effects of GLP-1RA may be considered in selection of an antidiabetes treatment regimen. Randomized clinical trials are warranted to confirm our findings.

Metformin use and respiratory outcomes in asthma-COPD overlap

Background

Metformin is associated with improved respiratory outcomes in asthma; however, metformin in COPD and asthma-COPD overlap (ACO) remains unexplored.

Objective

To determine the association between metformin use and respiratory outcomes in COPD and ACO.

Study design and methods

Participants with COPD (FEV1/FVC < 0.70) in the Genetic Epidemiology of COPD study (COPDGene®) were categorized as ACO (n = 510), defined as concurrent physician-diagnosed asthma before age 40 years, or COPD alone (n = 3459). We estimated the association of baseline metformin use with (1) rate of total and severe respiratory exacerbations during follow-up, (2) cross-sectional St. George’s Respiratory Questionnaire (SGRQ) score, six-minute walk distance (6MWD), and post-bronchodilator FEV1 percent predicted (FEV1pp), and (3) 5-year change in SGRQ, 6MWD, and FEV1pp. We also examined change in SGRQ, 6MWD and FEV1pp among participants who initiated metformin during follow-up (n = 108) compared to persistent metformin non-users (n = 2080). Analyses were adjusted for sociodemographic factors, medications, and comorbidities.

Results

Among participants with ACO, metformin use was associated with lower rate of total (adjusted incidence rate ratio [aIRR] 0.3; 95% confidence interval [95%CI] 0.11, 0.77) and severe exacerbations (aIRR 0.29; 95%CI 0.10, 0.89). Among participants with COPD alone, there was no association between metformin use with total (aIRR 0.98; 95%CI 0.62, 1.5) or severe exacerbations (aIRR 1.3; 95% CI 0.68, 2.4) (p-interaction < 0.05). Metformin use was associated with lower baseline SGRQ score (adjusted mean difference [aMD] − 2.7; 95%CI − 5.3, − 0.2) overall. Metformin initiation was associated with improved SGRQ score (aMD –10.0; 95% CI − 18.7, − 1.2) among participants with ACO but not COPD alone (p-interaction < 0.05). There was no association between metformin use and 6MWD or FEV1pp in any comparison.

Conclusions

Metformin use was associated with fewer respiratory exacerbations and improved quality of life among individuals with ACO but not COPD alone. Results suggest a potential role for metformin in ACO which requires further prospective study.

Trial Registry: NCT00608764

Analysis of prevalence and prognosis of type 2 diabetes mellitus in patients with acute exacerbation of COPD

BACKGROUND

For patients with acute exacerbation of COPD (AECOPD), type 2 diabetes mellitus (T2DM) as comorbidity have poor outcomes. However, data on the impact of previously diagnosed and new- diagnosed T2DM in such a patient population is lacking.

METHODS

Inpatients diagnosed with AECOPD in the department of Pulmonary and Critical Care Medicine of The First Hospital of China Medical University during 2011-2017 were enrolled. Data on demography, prevalence of type 2 DM, other comorbidities, hospital stays and laboratory tests (including arterial partial pressure of oxygen [PaO2]) results were recorded. Results were compared with AECOPD patients having previously diagnosed and new-diagnosed type 2 diabetes. Markers associated with development of type 2 DM and the prognosis of AECOPD patients were identified.

RESULTS

Of the 196 patients enrolled in this study, the overall prevalence of T2DM was 26%. The PaO2 in the newly diagnosed T2DM group was considerably lower versus non-diabetic group. The T2DM group had a longer hospital stay and higher troponin level versus the non-diabetic group. AECOPD patients with T2DM were found to be correlated with hypertension. Age, need for assisted ventilation, increased troponin, and elevated fasting blood glucose on admission were risk factors for death in hospitalized AECOPD patients.

CONCLUSIONS

AECOPD patients had a higher prevalence of T2DM than the general population; T2DM comorbidity caused lower PaO2, longer hospital stays, and increased troponin. Poor blood glucose control may increase the risk of death in AECOPD patients.

Oral treatment for diabetes using α-glucosidase inhibitors was a risk factor for chronic obstructive pulmonary disease: a cohort study

Objectives: Currently, diabetes mellitus (DM) and chronic obstructive pulmonary disease (COPD) have proven to be risk factors for each other. This study aimed to determine the risk relationship between COPD and five common oral medications for DM among patients with DM. Methods: This population-based cohort study was conducted from 2008 to 2013. Patient data were retrieved from the Longitudinal Health Insurance Database (LHID) of the National Health Insurance Research Database (NHIRD). After pairing by gender, age, and index date, time-to-event analysis and multiple regression analysis were performed to determine the factors associated with COPD in patients taking oral medication for DM, including age, gender, income, and comorbidities. We identified 1,028 patients who took oral medication for DM and 1,028 controls who did not take oral medication for DM. Results: We observed that the use of α-glucosidase inhibitors was associated with a higher risk of COPD (hazard ratio [HR]: 1.964, 95% confidence interval [CI]: 1.207-2.380). Furthermore, compared with the control group, α-glucosidase inhibitor users had a higher risk of COPD (HR: 2.295, 95% CI: 1.304-4.038), and no significant difference was observed in other oral medications for DM. Conclusions: Based on present results, we could suggest that patients with DM who used α-glucosidase inhibitors are probably a higher risk of COPD. We recommend that in the future, treatment with α-glucosidase inhibitors upregulate the occurrence of COPD might through gastrointestinal side effects and malnutrition.

Diabetic Pneumopathy-A New Diabetes-Associated Complication: Mechanisms, Consequences and Treatment Considerations

Patients with diabetes are over-represented among the total cases reported with "idiopathic" pulmonary fibrosis (IPF). This raises the question, whether this is an association only or whether diabetes itself can cause pulmonary fibrosis. Recent studies in mouse models of type 1 and type 2 diabetes demonstrated that diabetes causes pulmonary fibrosis. Both types of diabetes trigger a cascade, starting with increased DNA damage, an impaired DNA repair, and leading to persistent DNA damage signaling. This response, in turn, induces senescence, a senescence-associated-secretory phenotype (SASP), marked by the release of pro-inflammatory cytokines and growth factors, finally resulting in fibrosis. Restoring DNA repair drives fibrosis into remission, thus proving causality. These data can be translated clinically to patients with type 2 diabetes, characterized by long-term diabetes and albuminuria. Hence there are several arguments, to substitute the term "idiopathic" pulmonary fibrosis (IPF) in patients with diabetes (and exclusion of other causes of lung diseases) by the term "diabetes-induced pulmonary fibrosis" (DiPF). However, future studies are required to establish this term and to study whether patients with diabetes respond to the established therapies similar to non-diabetic patients.

Targeting cellular senescence as a new approach to chronic obstructive pulmonary disease therapy

Increasing evidence suggests that there is acceleration of normal lung ageing in chronic obstructive pulmonary disease (COPD), with the accumulation of senescent cells in the lung, which release an array of inflammatory proteins, which drive further senescence and disease progression. This suggests that drugs that target cellular senescence (senotherapies) may treat the underlying disease process in COPD and reduce disease progression and mortality. Several existing or future drugs may inhibit the development of cellular senescence, which is driven by chronic oxidative stress (senostatics), whereas other drugs selectively remove senescent cells (senolytics). Clinical studies of senotherapies have commenced in several age-related diseases, and these approaches appear to be safe and feasible, although no clinical studies in COPD patients have yet been reported.

FN3K expression in COPD: a potential comorbidity factor for cardiovascular disease

INTRODUCTION

Cigarette smoking and oxidative stress are common risk factors for the multi-morbidities associated with chronic obstructive pulmonary disease (COPD). Elevated levels of advanced glycation endproducts (AGE) increase the risk of cardiovascular disease (CVD) comorbidity and mortality. The enzyme fructosamine-3-kinase (FN3K) reduces this risk by lowering AGE levels.

METHODS

The distribution and expression of FN3K protein in lung tissues from stable COPD and control subjects, as well as an animal model of COPD, was assessed by immunohistochemistry. Serum FN3K protein and AGE levels were assessed by ELISA in patients with COPD exacerbations receiving metformin. Genetic variants within the FN3K and FN3K-RP genes were evaluated for associations with cardiorespiratory function in the Subpopulations and Intermediate Outcome Measures in COPD Study cohort.

RESULTS

This pilot study demonstrates that FN3K expression in the blood and human lung epithelium is distributed at either high or low levels irrespective of disease status. The percentage of lung epithelial cells expressing FN3K was higher in control smokers with normal lung function, but this induction was not observed in COPD patients nor in a smoking model of COPD. The top five nominal FN3K polymorphisms with possible association to decreased cardiorespiratory function (p<0.008-0.02), all failed to reach the threshold (p<0.0028) to be considered highly significant following multi-comparison analysis. Metformin enhanced systemic levels of FN3K in COPD subjects independent of their high-expression or low-expression status.

DISCUSSION

The data highlight that low and high FN3K expressors exist within our study cohort and metformin induces FN3K levels, highlighting a potential mechanism to reduce the risk of CVD comorbidity and mortality.

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.

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.

Cellular Senescence as a Mechanism and Target in Chronic Lung Diseases

Cellular senescence is now considered an important driving mechanism for chronic lung diseases, particularly chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis. Cellular senescence is due to replicative and stress-related senescence with activation of p53 and p16^INK4a, respectively, leading to activation of p21^CIP1 and cell cycle arrest. Senescent cells secrete multiple inflammatory proteins known as the senescence-associated secretory phenotype, leading to low-grade chronic inflammation, which further drives senescence. Loss of key antiaging molecules sirtuin-1 and sirtuin-6 may be important in acceleration of aging and arises from oxidative stress reducing phosphatase PTEN (phosphatase tensin homolog), thereby activating PI3K (phosphoinositide-3-kinase) and mTOR (mammalian target of rapamycin). MicroRNA-34a (miR-34a), which is regulated by PI3K-mTOR signaling, plays a pivotal role in reducing sirtuin-1/6, and its inhibition with an antagomir results in their restoration, reducing markers of senescence, reducing senescence-associated secretory phenotype, and reversing cell cycle arrest in epithelial cells from peripheral airways of patients with COPD. miR-570 is also involved in reduction of sirtuin-1 and cellular senescence and is activated by p38 mitogen-activated protein kinase. These miRNAs may be released from cells in extracellular vesicles that are taken up by other cells, thereby spreading senescence locally within the lung but also outside the lung through the circulation; this may account for comorbidities of COPD and other lung diseases. Understanding the mechanisms of cellular senescence may result in new treatments for chronic lung disease, either by inhibiting PI3K-mTOR signaling, by inhibiting specific miRNAs, or by deletion of senescent cells with senolytic therapies, already shown to be effective in experimental lung fibrosis.

Targeting defective pulmonary innate immunity - A new therapeutic option?

Chronic pulmonary conditions now account for 1 in 15 deaths in the US and mortality is increasing. Chronic obstructive pulmonary disease (COPD) is due to become the 3rd largest cause of mortality by 2030 and mortality from other respiratory conditions such as asthma, idiopathic pulmonary fibrosis and cystic fibrosis are not reducing. There is an urgent need for novel therapies to address this problem as many of the current strategies targeting inflammation are not sufficient. The innate immune system of the lung is an important defence against invading pathogens, but in many chronic pulmonary diseases, this system mounts an inappropriate response. In COPD, macrophages are increased in number, but fail to clear pathogens correctly and become highly activated. This leads to increased damage and remodelling of the airways. In idiopathic fibrosis, there is a switch of macrophage phenotype to a cell that promotes abnormal repair. Neutrophils also display dysfunction in COPD where aberrant migratory profiles may lead to increased damage to lung tissue and emphysema; while in cystic fibrosis the proteolytic lung environment damages neutrophil receptors leading to ineffective phagocytosis and migration. Targeting the innate immune system to restore 'normal function' could have enormous benefits. Improving phagocytosis of pathogens could reduce exacerbations and hence the associated decline in lung function, and novel therapeutics such as sulforaphane appear to do this in vitro. Other natural products such as resveratrol and derivatives also have anti-inflammatory properties. Statins have traditionally been used to manage cholesterol levels in hypercholesterolaemia, however these molecules also have beneficial effects on the innate immune cells. Statins have been shown to be anti-inflammatory and restore aberrant neutrophil chemotaxis in aged cells. Other possible agents that may be efficacious are senolytics. These compounds include natural products such as quercetin which have anti-inflammatory properties but can also suppress viral replication. As viruses have been shown to suppress phagocytosis of macrophages, it is possible that these compounds could have benefit during viral exacerbations to protect this innate response. These compounds demonstrate that it is possible to address defective innate responses in the lung but a better understanding of the mechanisms driving defective innate immunity in pulmonary disease may lead to improved therapeutics.

Role of Metabolic Reprogramming in Pulmonary Innate Immunity and Its Impact on Lung Diseases

Lung innate immunity is the first line of defence against inhaled allergens, pathogens and environmental pollutants. Cellular metabolism plays a key role in innate immunity. Catabolic pathways, including glycolysis and fatty acid oxidation (FAO), are interconnected with biosynthetic and redox pathways. Innate immune cell activation and differentiation trigger extensive metabolic changes that are required to support their function. Pro-inflammatory polarisation of macrophages and activation of dendritic cells, mast cells and neutrophils are associated with increased glycolysis and a shift towards the pentose phosphate pathway and fatty acid synthesis. These changes provide the macromolecules required for proliferation and inflammatory mediator production and reactive oxygen species for anti-microbial effects. Conversely, anti-inflammatory macrophages use primarily FAO and oxidative phosphorylation to ensure efficient energy production and redox balance required for prolonged survival. Deregulation of metabolic reprogramming in lung diseases, such as asthma and chronic obstructive pulmonary disease, may contribute to impaired innate immune cell function. Understanding how innate immune cell metabolism is altered in lung disease may lead to identification of new therapeutic targets. This is important as drugs targeting a number of metabolic pathways are already in clinical development for the treatment of other diseases such as cancer.

Role of metformin in treatment of patients with chronic obstructive pulmonary disease: a systematic review

Chronic obstructive pulmonary disease (COPD) is commonly associated with type 2 diabetes mellitus (T2DM). Metformin is a first-line treatment for most patients with T2DM, and may have antiaging, antioxidant, and anti-tumour effects. A few published studies report the use of metformin for the treatment of COPD in patients with or without T2DM, but the results are inconsistent. This study aimed to confirm the effectiveness and safety of metformin as a treatment option in patients with COPD. We performed a systematic search of PubMed, EMBASE, and the Cochrane database from their starting date to December 2017. Randomised controlled trials (RCTs), controlled clinical trials, and retrospective researches reporting the use of metformin for treating patients with COPD were identified. We included a total of six articles (involving 3,467 participants) and found that metformin may benefit patients with COPD and T2DM by improving health status and symptoms, hospitalisations, and mortality. There was no effect on patients with COPD without T2DM. Metformin causes minimal increases in plasma lactate concentrations without lactic acidosis and has little impact on blood glucose and minor adverse events. Metformin is safe and effective for treating COPD in patients with concomitant T2DM.

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.

Diabetes and Lung Disease: A Neglected Relationship

BACKGROUND

Diabetes mellitus is a systemic disorder associated with inflammation and oxidative stress which may target many organs such as the kidney, retina, and the vascular system. The pathophysiology, mechanisms, and consequences of diabetes on these organs have been studied widely. However, no work has been done on the concept of the lung as a target organ for diabetes and its implications for lung diseases.

AIM

In this review, we aimed to investigate the effects of diabetes and hypoglycemic agent on lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, and lung cancer. We also reviewed the potential mechanisms by which these effects may affect lung disease patients.

RESULTS

Our results suggest that diabetes can affect the severity and clinical course of several lung diseases.

CONCLUSIONS

Although the diabetes-lung association is epidemiologically and clinically well-established, especially in asthma, the underlying mechanism and pathophysiology are not been fully understood. Several mechanisms have been suggested, mainly associated with the pro-inflammatory and proliferative properties of diabetes, but also in relation to micro- and macrovascular effects of diabetes on the pulmonary vasculature. Also, hypoglycemic drugs may influence lung diseases in different ways. For example, metformin was considered a potential therapeutic agent in lung diseases, while insulin was shown to exacerbate lung diseases; this suggests that their effects extend beyond their hypoglycemic properties.

Pulmonary Diseases and Ageing

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis are regarded as a diseases of accelerated lung ageing and show all of the hallmarks of ageing, including telomere shortening, cellular senescence, activation of PI3 kinase-mTOR signaling, impaired autophagy, mitochondrial dysfunction, stem cell exhaustion, epigenetic changes, abnormal microRNA profiles, immunosenescence and a low grade chronic inflammation due to senescence-associated secretory phenotype (SASP). Many of these ageing mechanisms are driven by exogenous and endogenous oxidative stress. There is also a reduction in anti-ageing molecules, such as sirtuins and Klotho, which further accelerate the ageing process. Understanding these molecular mechanisms has identified several novel therapeutic targets and several drugs and dietary interventions are now in development to treat chronic lung disease.

Effects of metformin use on total mortality in patients with type 2 diabetes and chronic obstructive pulmonary disease: A matched-subject design

BACKGROUNDS

Few studies have investigated the therapeutic effects of metformin in patients with type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD). We compared the risk of all-cause mortality between metformin users and nonusers.

METHODS

We conducted a retrospective cohort study for patients with T2DM and COPD who were enrolled between January 1, 2000 and June 30, 2012. Individuals with exacerbated symptoms who were hospitalized or sent to the emergency department (ED) were identified as having exacerbated COPD; outpatient claims were identified as having stable COPD. A total of 40,597 metformin users and 39,529 nonusers comprised the cohort of stable COPD; 14,001 metformin users and 21,613 nonusers comprised the cohort of exacerbated COPD. Users and nonusers were matched using propensity score (1:1). Our primary outcome was all-cause mortality.

RESULTS

A total of 19,505 metformin users were matched to 19,505 nonusers in the cohort of diabetes with stable COPD. The mean follow-up time was 3.91 years. All-cause mortality was reported in 1326 and 1609 metformin users and nonusers, respectively. After multivariate adjustment, metformin users had lower risk of mortality (adjusted hazard ratio [aHR] = 0.84, p < 0.0001). Metformin users had significantly lower risk of noncardiovascular death (aHR = 0.86, p = 0.0008). A total of 7721 metformin users were matched to 7721 nonusers in the cohort of diabetes with exacerbated COPD. The mean follow-up time was 3.18 years. All-cause mortality was reported in 1567 and 1865 metformin users and nonusers, respectively. After multivariate adjustment, metformin users had significantly lower risk of mortality (aHR = 0.89, p = 0.002) and cardiovascular death (aHR = 0.70, p = 0.01).

CONCLUSION

This large-series, nationwide cohort study demonstrated that metformin use could significantly lower the risk of all-cause mortality in patients with T2DM and either stable or exacerbated COPD.

Type 2 diabetes: A protective factor for COPD?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and type 2 diabetes (T2DM) are common comorbidities. COPD is a known risk factor for incident T2DM, however few studies have examined the relationship in reverse. The primary aim of this study was to compare the incidence of COPD in people with and without T2DM.

MATERIALS AND METHODS

We conducted a retrospective case-control study using a long-established English general practice network database (n=894,646). We matched 29,217 cases of T2DM with controls, adjusting for age, gender, smoking status, BMI and social deprivation, to achieve 1:1 propensity matching and compared the rate of incident COPD over eight years of follow-up. We performed a secondary analysis to investigate the effect of insulin, metformin and sulphonylureas on COPD incidence.

RESULTS

People with T2DM had a reduced risk of COPD compared to matched controls over the follow-up period (HR 0.89, 95%CI 0.79-0.93). 48.5% of those with T2DM were ex-smokers compared with 27.3% of those without T2DM. Active smoking rates were 20.4% and 23.7% respectively. Insulin, metformin and sulphonylureas were not associated with incident COPD.

CONCLUSIONS

People with T2DM are less likely to be diagnosed with COPD than matched controls. This may be due to positive lifestyle changes, such as smoking cessation in those with T2DM.

Role of airway glucose in bacterial infections in patients with chronic obstructive pulmonary disease

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) have increased susceptibility to respiratory tract infection, which contributes to disease progression and mortality, but mechanisms of increased susceptibility to infection remain unclear.

OBJECTIVES

The aim of this study was to determine whether glucose concentrations were increased in airway samples (nasal lavage fluid, sputum, and bronchoalveolar lavage fluid) from patients with stable COPD and to determine the effects of viral infection on sputum glucose concentrations and how airway glucose concentrations relate to bacterial infection.

METHODS

We measured glucose concentrations in airway samples collected from patients with stable COPD and smokers and nonsmokers with normal lung function. Glucose concentrations were measured in patients with experimentally induced COPD exacerbations, and these results were validated in patients with naturally acquired COPD exacerbations. Relationships between sputum glucose concentrations, inflammatory markers, and bacterial load were examined.

RESULTS

Sputum glucose concentrations were significantly higher in patients with stable COPD compared with those in control subjects without COPD. In both experimental virus-induced and naturally acquired COPD exacerbations, sputum and nasal lavage fluid glucose concentrations were increased over baseline values. There were significant correlations between sputum glucose concentrations and sputum inflammatory markers, viral load, and bacterial load. Airway samples with higher glucose concentrations supported more Pseudomonas aeruginosa growth in vitro.

CONCLUSIONS

Airway glucose concentrations are increased in patients with stable COPD and further increased during COPD exacerbations. Increased airway glucose concentrations might contribute to bacterial infections in both patients with stable and those with exacerbated COPD. This has important implications for the development of nonantibiotic therapeutic strategies for the prevention or treatment of bacterial infection in patients with COPD.

Inhalational supplementation of metformin butyrate: A strategy for prevention and cure of various pulmonary disorders

The management of chronic lung diseases such as cancer, asthma, COPD and pulmonary hypertension remains unsatisfactory till date, and several strategies are being tried to control the same. Metformin, a popular anti-diabetic drug has shown promising effects in pre-clinical studies and has been subject to several trials in patients with debilitating pulmonary diseases. However, the clinical evidence for the use of metformin in these conditions is disappointing. Recent observations suggest that metformin use in diabetic patients is associated with an increase in butyrate-producing bacteria in the gut microbiome. Butyrate, similar to metformin, shows beneficial effects in pathological conditions found in pulmonary diseases. Further, the pharmacokinetic data of metformin suggests that metformin is predominantly concentrated in the gut, even after absorption. Butyrate, on the other hand, has a short half-life and thus oral supplementation of butyrate and metformin is unlikely to result in high concentrations of these drugs in the lung. In this paper, we review the pre-clinical studies of metformin and butyrate pertaining to pathologies commonly encountered in chronic lung diseases and underscore the need to administer these drugs directly to the lung via the inhalational route.

Metformin and risk of chronic obstructive pulmonary disease in diabetes patients

PURPOSE

This study aimed to investigate whether metformin can affect risk of chronic obstructive pulmonary disease (COPD) in type 2 diabetes (T2D) patients.

METHODS

T2D patients newly diagnosed during 1999-2005 were enrolled from the reimbursement database of Taiwan's National Health Insurance system and followed up to 31 December 2011. Analyses were conducted in an unmatched cohort (92,272 ever-users and 10,697 never-users of metformin) and a propensity score (PS) matched pair cohort (10,697 ever-users and 10,697 never-users). Cox regression incorporated into the inverse probability of treatment weighting using the PS was used to estimate hazard ratios (HRs).

RESULTS

In the unmatched cohort, 2573 never-users and 13,840 ever-users developed COPD with respective incidences of 5994.64 and 3393.19 per 100,000 person-years. The overall HR was 0.560 (95% confidence interval [CI]: 0.537-0.584). HRs for the first (<25.27months), second (25.27-55.97months) and third (>55.97months) tertiles of cumulative duration were 1.021 (0.975-1.070), 0.575 (0.548-0.603) and 0.265 (0.252-0.280), respectively. Analyses of the matched cohort showed an overall HR of 0.643 (0.605-0.682), with HRs of 1.212 (1.122-1.309), 0.631 (0.578-0.689) and 0.305 (0.273-0.340) for the respective tertiles.

CONCLUSION

A reduced risk of COPD is observed in metformin users with T2D.

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

Background

Chronic obstructive pulmonary disease (COPD) is associated with persistent systemic inflammation. Anti-inflammatory therapies have been shown to decrease acute exacerbations of COPD. The antidiabetic medication metformin decreases oxidative stress and inflammation and may benefit patients with COPD. We aimed at investigating the effect of metformin on health care utilizations in patients with coexisting COPD and diabetes mellitus (DM).

Methods

We studied 5% Medicare beneficiaries with coexisting COPD and DM prescribed metformin or other antidiabetics during the period 2007-2010. The primary outcome was COPD-specific emergency room (ER) visits and hospitalizations; the secondary outcome was all-cause ER visits and hospitalizations over the 2-year follow-up after the index antidiabetic prescription. The effects of metformin were examined by COPD complexity and compared with the effects of other antidiabetic medications.

Results

Among 11,260 patients, 3,193 were metformin users and 8,067 were nonusers. Metformin users were younger, were less sick, were less likely to be on oxygen, and had fewer hospitalizations in the prior year compared with the nonusers. Over a 2-year period, metformin users had lower COPD-specific and all-cause ER visits and hospitalizations (7.11% vs 9.61%, p<0.0001; and 61.63% vs 71.27%, p<0.0001, respectively). In a stratified multivariable analysis, the odds of COPD-specific ER visits and hospitalizations were lower in patients with low-complexity COPD (adjusted odds ratio =0.66, 95% confidence interval =0.52-0.85). However, patients with all COPD complexities get benefits of metformin on all-cause ER visits and hospitalizations.

Conclusion

The use of metformin in patients with coexisting COPD and DM was associated with fewer COPD-specific ER visits and hospitalizations, especially in low-complexity COPD.

Pleiotropic effects of hypoglycemic agents: implications in asthma and COPD

Diabetes mellitus (DM) is a complex multifactorial disease due to the interaction between environmental noxae and genetic predisposition. Furthermore, an increased association between DM, especially Type 2 diabetes mellitus (T2DM), and the onset of pulmonary function impairment with a bronchial hyperresponsiveness has been documented. DM is a risk factor for accelerated decline in FEV₁ and the development of asthma and COPD. The increased blood glucose concentrations along with higher levels of oxidative stress and inflammation can influence the pulmonary function and, since hypoglycemic drugs can act on these different defects we can hypothesize their direct effect on obstructive pulmonary diseases. Metformin, a biguanide, is the molecule having several evidences of its action on asthma and COPD in patients with T2DM. In this population, Metformin can ameliorate pulmonary outcomes reducing high glucose concentrations, inflammation through the activation of the AMP-activated protein kinase, leading to the decreased production of pro-inflammatory cytokines and blunting allergic eosinophilic airway inflammation. There are evidences of Pioglitazone role on asthma, since the activation of PPARγ Pioglitazone might inhibit the synthesis and release of pro-inflammatory cytokines. Indeed, Pioglitazone can improve symptoms associated with asthma reducing episodes of exacerbation and oral steroid prescription. Finally, randomized clinical trials using hypoglycemic agents on patients with asthma and COPD with and without DM should be proposed as well as the implementation of a new formulation of hypoglycemic agents to make it possible to administer it via aerosol.

Drug repurposing to treat asthma and allergic disorders: Progress and prospects

Allergy and atopic asthma have continued to become more prevalent in modern society despite the advent of new treatments, representing a major global health problem. Common medications such as antihistamines and steroids can have undesirable long-term side-effects and lack efficacy in some resistant patients. Biologic medications are increasingly given to treatment-resistant patients, but they can represent high costs, complex dosing and management, and are not widely available around the world. The field needs new, cheap, and convenient treatment options in order to bring better symptom relief to patients. Beyond continued research and development of new drugs, a focus on drug repurposing could alleviate this problem by repositioning effective and safe small-molecule drugs from other fields of medicine and applying them toward the treatment for asthma and allergy. Herein, preclinical models, case reports, and clinical trials of drug repurposing efficacy in allergic disease are reviewed. Novel drugs are also proposed for repositioning based on their mechanism of action to treat asthma and allergy. Overall, drug repurposing could become increasingly important as a way of advancing allergy and atopic asthma therapy, filling a need in treatment of patients today.