Hyperinsulinemia adversely affects lung structure and function

Adiposity, immunity, and inflammation: interrelationships in health and disease: a report from 24th Annual Harvard Nutrition Obesity Symposium, June 2023

The rapidly evolving field of immunometabolism explores how changes in local immune environments may affect key metabolic and cellular processes, including that of adipose tissue. Importantly, these changes may contribute to low-grade systemic inflammation. In turn, chronic low-grade inflammation affecting adipose tissue may exacerbate the outcome of metabolic diseases. Novel advances in our understanding of immunometabolic processes may critically lead to interventions to reduce disease severity and progression. An important example in this regard relates to obesity, which has a multifaceted effect on immunity, activating the proinflammatory pathways such as the inflammasome and disrupting cellular homeostasis. This multifaceted effect of obesity can be investigated through study of downstream conditions using cellular and systemic investigative techniques. To further explore this field, the National Institutes of Health P30 Nutrition Obesity Research Center at Harvard, in partnership with Harvard Medical School, assembled experts to present at its 24th Annual Symposium entitled "Adiposity, Immunity, and Inflammation: Interrelationships in Health and Disease" on 7 June, 2023. This manuscript seeks to synthesize and present key findings from the symposium, highlighting new research and novel disease-specific advances in the field. Better understanding the interaction between metabolism and immunity offers promising preventative and treatment therapies for obesity-related immunometabolic diseases.

Influence of SphK1 on Inflammatory Responses in Lipopolysaccharide-Challenged RAW 264.7 Cells

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are serious respiratory disorders caused by a variety of intrapulmonary and extrapulmonary factors. Their incidence is increasing year by year, with high morbidity and mortality rates and lack of effective treatment. Inflammation plays a crucial role in ALI development, with sphingosine kinase 1 (SphK1) being a pivotal enzyme influencing sphingolipid metabolism and participating in inflammatory responses. However, the specific impact and the signaling pathway underlying SphK1 in lipopolysaccharide (LPS)-induced ALI/ARDS are poorly understood. This investigation aimed to explore the influence of SphK1 on inflammation and delve into the mechanistic aspects of inflammation in RAW 264.7 cells during LPS-induced ALI, which is of great importance in providing new targets and strategies for ALI/ARDS treatment.

Mangiferin alleviates diabetic pulmonary fibrosis in mice via inhibiting endothelial-mesenchymal transition through AMPK/FoxO3/SIRT3 axis

Diabetes mellitus results in numerous complications. Diabetic pulmonary fibrosis (DPF), a late pulmonary complication of diabetes, has not attracted as much attention as diabetic nephropathy and cardiomyopathy. Mangiferin (MF) is a natural small molecular compound that exhibits a variety of pharmacological effects including anti-inflammatory, anti-cancer, anti-diabetes, and anti-fibrosis effects. In this study, we investigated whether long-term diabetes shock induces DPF, and explored whether MF had a protective effect against DPF. We first examined the lung tissues and sections of 20 diabetic patients obtained from discarded lung surgical resection specimens and found that pulmonary fibrosis mainly accumulated around the pulmonary vessels, accompanied by significantly enhanced endothelial-mesenchymal transition (EndMT). We established a mouse model of DPF by STZ injections. Ten days after the final STZ injection, the mice were administered MF (20, 60 mg/kg, i.g.) every 3 days for 4 weeks, and kept feeding until 16 weeks and euthanized. We showed that pulmonary fibrotic lesions were developed in the diabetic mice, which began around the pulmonary vessels, while MF administration did not affect long-term blood glucose levels, but dose-dependently alleviated diabetes-induced pulmonary fibrosis. In human umbilical vein endothelial cells (HUVECs), exposure to high glucose (33.3 mM) induced EndMT, which was dose-dependently inhibited by treatment with MF (10, 50 μM). Furthermore, MF treatment promoted SIRT3 expression in high glucose-exposed HUVECs by directly binding to AMPK to enhance the activity of FoxO3, which finally reversed diabetes-induced EndMT. We conclude that MF attenuates DPF by inhibiting EndMT through the AMPK/FoxO3/SIRT3 axis. MF could be a potential candidate for the early prevention and treatment of DPF.

Systemic Inflammation in Asthma: What Are the Risks and Impacts Outside the Airway?

Airway inflammation in asthma has been well recognized for several decades, with general agreement on its role in asthma pathogenesis, symptoms, propensity toward exacerbation, and decline in lung function. This has led to universal recommendation in asthma management guidelines to incorporate the use of inhaled corticosteroid as an anti-inflammatory therapy for all patients with persistent asthma symptoms. However, there has been limited attention paid to the presence and potential impact of systemic inflammation in asthma. Accumulating evidence from epidemiological observations and cohort studies points to a host of downstream organ dysfunction in asthma especially among patients with longstanding or more severe disease, frequent exacerbations, and underlying risk factors for organ dysfunction. Most studies to date have focused on cognitive impairment, depression/anxiety, metabolic syndrome, and cardiovascular abnormalities. In this review, we summarize some of the evidence demonstrating these abnormalities and highlight the proposed mechanisms and potential benefits of treatment in limiting these extrapulmonary abnormalities in patients with asthma. The goal of this commentary is to raise awareness of the importance of recognizing potential extrapulmonary conditions associated with systemic inflammation of asthma. This area of treatment of patients with asthma is a large unmet need.

Effect of Semaglutide and Empagliflozin on Pulmonary Structure and Proteomics in Obese Mice

Objective

This study utilized proteomics to investigate changes in protein expression associated with lung health in obese mice exposed to semaglutide and empagliflozin through a high-fat diet.

Methods

Twenty-eight male C57BL/6JC mice were randomly assigned to two groups: a control diet group (n = 7) and a high-fat diet group (n = 21). The HFD group was further divided into three groups: HFD group (n = 7), Sema group (n = 7), and Empa group (n = 7). Post-treatment, mice underwent assessments including glucose tolerance, lipids, oxidative stress markers, body weight, lung weight, and structure. Proteomics identified differentially expressed proteins (DEPs) in lung tissue, and bioinformatics analyzed the biological processes and functions of these proteins.

Results

Semaglutide and empagliflozin significantly attenuated obesity-induced hyperglycemia, abnormal lipid metabolism, oxidative stress response, and can decrease alveolar wall thickness, enlarge alveolar lumen, and reduce collagen content in lung tissue. Both medications also attenuated lung elastic fibre cracking and disintegration. In the HFD/NCD group, there were 66 DEPs, comprising 30 proteins that were increased and 36 that were decreased. Twenty-three DEPs overlapped between Sema/HFD and Empa/HFD, with 11 up-regulated and 12 down-regulated simultaneously. After analysing DEPs in different groups, four proteins - LYVE1, BRAF, RGCC, and CHMP5 - were all downregulated in the HFD group and upregulated by semaglutide and empagliflozin treatment.

Conclusion

This study demonstrates that obesity induced by a high-fat diet causes a reduction in the expression of LYVE1, BRAF, RGCC, and CHMP5 proteins, potentially affecting lung function and structure in mice. Significantly, the administration of semaglutide and empagliflozin elevates the levels of these proteins, potentially offering therapeutic benefits against lung injury caused by obesity. Merging semaglutide with empagliflozin may exert a more pronounced impact.

Unraveling the Link between Ιnsulin Resistance and Bronchial Asthma

Evidence from large epidemiological studies has shown that obesity may predispose to increased Th2 inflammation and increase the odds of developing asthma. On the other hand, there is growing evidence suggesting that metabolic dysregulation that occurs with obesity, and more specifically hyperglycemia and insulin resistance, may modify immune cell function and in some degree systemic inflammation. Insulin resistance seldom occurs on its own, and in most cases constitutes a clinical component of metabolic syndrome, along with central obesity and dyslipidemia. Despite that, in some cases, hyperinsulinemia associated with insulin resistance has proven to be a stronger risk factor than body mass in developing asthma. This finding has been supported by recent experimental studies showing that insulin resistance may contribute to airway remodeling, promotion of airway smooth muscle (ASM) contractility and proliferation, increase of airway hyper-responsiveness and release of pro-inflammatory mediators from adipose tissue. All these effects indicate the potential impact of hyperinsulinemia on airway structure and function, suggesting the presence of a specific asthma phenotype with insulin resistance. Epidemiologic studies have found that individuals with severe and uncontrolled asthma have a higher prevalence of glycemic dysfunction, whereas longitudinal studies have linked glycemic dysfunction to an increased risk of asthma exacerbations. Since the components of metabolic syndrome interact with one another so much, it is challenging to identify each one's specific role in asthma. This is why, over the last decade, additional studies have been conducted to determine whether treatment of type 2 diabetes mellitus affects comorbid asthma as shown by the incidence of asthma, asthma control and asthma-related exacerbations. The purpose of this review is to present the mechanism of action, and existing preclinical and clinical data, regarding the effect of insulin resistance in asthma.

Obesity and Insulin Resistance in Asthma Pathogenesis and Clinical Outcomes

Common inflammatory ground links obesity, insulin resistance, and asthma. As recognition of their interplay, one worsening the natural course of the other, is recognised, questions remain about how to adequately address them altogether to improve clinical outcomes. The present manuscript sheds light on the problem, describing possible pathophysiological links, clinical views, and therapeutic challenges, raising questions about what remains to be done, and calling for multidisciplinary treatment of these patients to detect diseases early and adequately address them before they become full-blown and deteriorate their health and quality of life.

Antifibrotic effects of sodium-glucose cotransporter-2 inhibitors: A comprehensive review

BACKGROUND AND AIMS

Scar tissue accumulation in organs is the underlying cause of many fibrotic diseases. Due to the extensive array of organs affected, the long-term nature of fibrotic processes and the large number of people who suffer from the negative impact of these diseases, they constitute a serious health problem for modern medicine and a huge economic burden on society. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a relatively new class of anti-diabetic pharmaceuticals that offer additional benefits over and above their glucose-lowering properties; these medications modulate a variety of diseases, including fibrosis. Herein, we have collated and analyzed all available research on SGLT2is and their effects on organ fibrosis, together with providing a proposed explanation as to the underlying mechanisms.

METHODS

PubMed, ScienceDirect, Google Scholar and Scopus were searched spanning the period from 2012 until April 2023 to find relevant articles describing the antifibrotic effects of SGLT2is.

RESULTS

The majority of reports have shown that SGLT2is are protective against lung, liver, heart and kidney fibrosis as well as arterial stiffness. According to the results of clinical trials and animal studies, many SGLT2 inhibitors are promising candidates for the treatment of fibrosis. Recent studies have demonstrated that SGLT2is affect an array of cellular processes, including hypoxia, inflammation, oxidative stress, the renin-angiotensin system and metabolic activities, all of which have been linked to fibrosis.

CONCLUSION

Extensive evidence indicates that SGLT2is are promising treatments for fibrosis, demonstrating protective effects in various organs and influencing key cellular processes linked to fibrosis.

Association between glycated haemoglobin and the risk of chronic obstructive pulmonary disease: A prospective cohort study in UK biobank

AIMS

To investigate the association between glycated haemoglobin (HbA1c) levels and chronic obstructive pulmonary disease (COPD) incidents in the general population, and the association between HbA1c levels and mortality in patients with COPD.

MATERIALS AND METHODS

We investigated the association of HbA1c levels with COPD risk in the general population in the UK Biobank, using data from 420 065 participants. Survival analysis was conducted for 18 854 patients with COPD. We used restricted cubic spline analysis to assess the dose-response relationship between HbA1c levels and COPD risk and survival. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 12.3 years, 11 556 COPD cases were recorded. HbA1c had a non-linear relationship with COPD risk (p for non-linearity < .05). Compared with the quintile 2 (32.2-<34.3 mmol/mol), those with HbA1c levels above 38.7 mmol/mol (quintile 5) had a 22% (HR, 1.22, 95% CI: 1.15-1.30) higher risk of COPD. Compared with the HbA1c decile 2 (30.5-<32.2 mmol/mol), the HRs (95% CI) of COPD risk were 1.16 (1.03-1.30) and 1.36 (1.24-1.50) in the lowest HbA1c decile (<30.5 mmol/mol) and highest decile (≥41.0 mmol/mol), respectively. The increased COPD risk associated with HbA1c was more pronounced in younger, current smokers, passive smokers, and participants with a higher Townsend deprivation index (all p for interaction < .05). Among patients with COPD, 4569 COPD cases died (488 because of COPD) during a median follow-up of 5.4 years. Regarding COPD survival, HbA1c had a non-linear relationship with all-cause death (p for non-linearity < .05). Those with HbA1c quintile 5 (≥38.7 mmol/mol) had a 23% (HR, 1.23, 95% CI: 1.10-1.37) higher risk of all-cause death compared with the quintile 2 (32.2-<34.3 mmol/mol). Compared with the HbA1c decile 4 (33.3-<34.3 mmol/mol), those in the lowest HbA1c decile (<30.5 mmol/mol) and highest HbA1c decile (≥41.0 mmol/mol) had 22% (HR, 1.22; 95% CI: 1.01-1.47) and 28% (HR, 1.28; 95% CI: 1.11-1.48) higher risk for overall death. However, no significant association was observed between HbA1c levels and the risk of COPD-specific death.

CONCLUSIONS

Our findings indicated that lower and higher HbA1c levels were associated with a higher risk of COPD. In COPD cases, lower and higher HbA1c levels were associated with a higher COPD all-cause death risk.

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.

Mechanistic Links Between Obesity and Airway Pathobiology Inform Therapies for Obesity-Related Asthma

Obesity-related asthma is associated with a high disease burden and a poor response to existent asthma therapies, suggesting that it is a distinct asthma phenotype. The proposed mechanisms that contribute to obesity-related asthma include the effects of the mechanical load of obesity, adipokine perturbations, and immune dysregulation. Each of these influences airway smooth muscle function. Mechanical fat load alters airway smooth muscle stretch affecting airway wall geometry, airway smooth muscle contractility, and agonist delivery; weight loss strategies, including medically induced weight loss, counter these effects. Among the metabolic disturbances, insulin resistance and free fatty acid receptor activation influence distinct signaling pathways in the airway smooth muscle downstream of both the M2 muscarinic receptor and the β2 adrenergic receptor, such as phospholipase C and the extracellular signal-regulated kinase signaling cascade. Medications that decrease insulin resistance and dyslipidemia are associated with a lower asthma disease burden. Leptin resistance is best understood to modulate muscarinic receptors via the neural pathways but there are no specific therapies for leptin resistance. From the immune perspective, monocytes and T helper cells are involved in systemic pro-inflammatory profiles driven by obesity, notably associated with elevated levels of interleukin-6. Clinical trials on tocilizumab, an anti-interleukin antibody, are ongoing for obesity-related asthma. This armamentarium of therapies is distinct from standard asthma medications, and once investigated for its efficacy and safety among children, will serve as a novel therapeutic intervention for pediatric obesity-related asthma. Irrespective of the directionality of the association between asthma and obesity, airway-specific mechanistic studies are needed to identify additional novel therapeutic targets for obesity-related asthma.

Type 2 Diabetes Mellitus and Asthma: Pathomechanisms of Their Association and Clinical Implications

Type 2 diabetes mellitus (T2DM) and asthma are chronic illnesses concomitantly present in a significant percentage of the population. Their comorbidity is associated with poor disease control and lower quality of life, thus imposing a substantial medical and economic burden worldwide. This review investigates the association between asthma and T2DM, in terms of pathogenesis, clinical outcomes, and therapeutic opportunities. Our review found an increased risk of asthma among diabetics, and vice versa. Having diabetes and poor glycemic control is associated with an increased rate of asthma exacerbations and increased mortality among those hospitalized for asthma exacerbations. The mechanisms postulated for the diabetes-asthma association include chronic low-grade inflammation, obesity, hyperinsulinemia, and possibly diabetic pneumopathy. Usage of metformin, which is the first-line drug for type 2 diabetes, was found to be associated with a decreased asthma occurrence, asthma exacerbations, and asthma-related hospitalizations. Glucagon-like peptide 1 receptor agonists were also found to be associated with a lower occurrence of asthma exacerbations. Thiazolidinediones are also associated with lower rates of asthma exacerbations, but their clinical efficacy for the same was suggested to be limited. This literature review supports a partly causative association between asthma and diabetes. This comorbidity leads to poor patient compliance, worse disease outcomes, and poor quality of life. Thus, further studies are warranted to explore the prognostic implications, therapeutic opportunities, and specific clinical practice algorithms for patients with concurrent asthma and type 2 diabetes mellitus.

Body Composition and COPD: A New Perspective

The proportion of obese or overweight patients in COPD patients is increasing. Although BMI, WC and other easy to measure indicators have been proven to be related to the risk of COPD, they cannot accurately reflect the distribution and changes of body composition, ignoring the body composition (such as fat distribution, muscle content, water content, etc.), the relationship between it and disease risk may be missed. By analyzing the correlation between different body composition indexes and COPD patients, we can provide new research ideas for the prognosis judgment or intervention of COPD disease.

The interplay between diabetes mellitus and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) and diabetes mellitus (DM) are common and chronic disorders. COPD is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities and it is considered currently the fourth leading cause of death worldwide. DM is a systemic disease characterized by a chronic hyperglycemia associated with inflammation and oxidative stress. The relationship between the two conditions is not completely understood and conflicting results are reported in the literature. Many studies have investigated the mechanisms through with the respiratory disease is associated with an increased risk of metabolic condition or whether the incidence risk of COPD in individuals affected by DM is higher. The link between the two chronic conditions has relevant implications in the management of patients affected by the both of them. Respiratory patients should be screened for diabetes mellitus as a frequent comorbidity of lung disease since therapeutic options should be assessed about risk-to-benefit ratios associated with the indication for the steroid use. Furthermore, the role of hyperglycemia on pulmonary function (e.g. infection or inflammatory processes) should be evaluated in DM. Finally, in presence of both diseases potential treatment interactions should be considered. In this overview we explored the common aspects of both clinical chronic illnesses and investigated the interplay between the two conditions.

Metabolic Contributions to Pathobiology of Asthma

Asthma is a heterogenous disorder driven by inflammatory mechanisms that result in multiple phenotypes. Given the complex nature of this condition, metabolomics is being used to delineate the pathobiology of asthma. Metabolomics is the study of metabolites in biology, which includes biofluids, cells, and tissues. These metabolites have a vital role in a disease as they contribute to the pathogenesis of said condition. This review describes how macrometabolic and micrometabolic studies pertaining to these metabolites have contributed to our current understanding of asthma, as well as its many phenotypes. One of the main phenotypes this review will discuss in further detail is obesity as well as diabetes. Distinct roles of metabolites in endotyping asthma and their translation to potential therapy development for asthma is also discussed in this review.

Pathogenesis of (smoking-related) non-communicable diseases-Evidence for a common underlying pathophysiological pattern

Non-communicable diseases, like diabetes, cardiovascular diseases, cancer, stroke, chronic obstructive pulmonary disease, osteoporosis, arthritis, Alzheimer's disease and other more are a leading cause of death in almost all countries. Lifestyle factors, especially poor diet and tobacco consumption, are considered to be the most important influencing factors in the development of these diseases. The Western diet has been shown to cause a significant distortion of normal physiology, characterized by dysregulation of the sympathetic nervous system, renin-angiotensin aldosterone system, and immune system, as well as disruption of physiological insulin and oxidant/antioxidant homeostasis, all of which play critical roles in the development of these diseases. This paper addresses the question of whether the development of smoking-related non-communicable diseases follows the same pathophysiological pattern. The evidence presented shows that exposure to cigarette smoke and/or nicotine causes the same complex dysregulation of physiology as described above, it further shows that the factors involved are strongly interrelated, and that all of these factors play a key role in the development of a broad spectrum of smoking-related diseases. Since not all smokers develop one or more of these diseases, it is proposed that this disruption of normal physiological balance represents a kind of pathogenetic "basic toolkit" for the potential development of a range of non-communicable diseases, and that the decision of whether and what disease will develop in an individual is determined by other, individual factors ("determinants"), such as the genome, epigenome, exposome, microbiome, and others. The common pathophysiological pattern underlying these diseases may provide an explanation for the often poorly understood links between non-communicable diseases and disease comorbidities. The proposed pathophysiological process offers new insights into the development of non-communicable diseases and may influence the direction of future research in both prevention and therapy.

The Impact of Insulin Resistance on Loss of Lung Function and Response to Treatment in Asthma

Rationale: The role of obesity-associated insulin resistance (IR) in airflow limitation in asthma is uncertain. Objectives: Using data in the Severe Asthma Research Program 3 (SARP-3), we evaluated relationships between homeostatic measure of IR (HOMA-IR), lung function (cross-sectional and longitudinal analyses), and treatment responses to bronchodilators and corticosteroids. Methods: HOMA-IR values were categorized as without (<3.0), moderate (3.0-5.0), or severe (>5.0). Lung function included FEV1 and FVC measured before and after treatment with inhaled albuterol and intramuscular triamcinolone acetonide and yearly for 5 years. Measurements and Main Results: Among 307 participants in SARP-3, 170 (55%) were obese and 140 (46%) had IR. Compared with patients without IR, those with IR had significantly lower values for FEV1 and FVC, and these lower values were not attributable to obesity effects. Compared with patients without IR, those with IR had lower FEV1 responses to β-adrenergic agonists and systemic corticosteroids. The annualized decline in FEV1 was significantly greater in patients with moderate IR (-41 ml/year) and severe IR (-32 ml/year,) than in patients without IR (-13 ml/year, P < 0.001 for both comparisons). Conclusions: IR is common in asthma and is associated with lower lung function, accelerated loss of lung function, and suboptimal lung function responses to bronchodilator and corticosteroid treatments. Clinical trials in patients with asthma and IR are needed to determine if improving IR might also improve lung function.

High Insulin in Early Childhood Is Associated with Subsequent Asthma Risk Independent of Body Mass Index

BACKGROUND

Asthma and obesity are major, interconnected public health challenges that usually have their origins in childhood, and for which the relationship is strengthened among those with insulin resistance.

OBJECTIVE

To determine whether high insulin in early life confers increased longitudinal risk for asthma independent of body mass index.

METHODS

The study used data from the Tucson Children's Respiratory Study (TCRS) and the Avon Longitudinal Study of Parents and Children (ALSPAC). Nonfasting insulin was measured in TCRS participants at age 6 years and fasting insulin in ALSPAC participants at age 8 years. Physician-diagnosed active asthma was determined at baseline and at subsequent assessments up to age 36 years in TCRS and 17 years in ALSPAC.

RESULTS

In TCRS, high insulin (upper quartile) at age 6 years was associated with increased odds of having active asthma from ages 8 to 36 years compared with low insulin (odds ratio,1.98; 95% CI, 1.28-3.05; P = .002). Similarly, in ALSPAC, high insulin was associated with a significantly higher risk of active asthma from ages 11 to 17 years compared with low insulin (odds ratio, 1.59; 95% CI, 1.12-2.27; P = .009). These findings were independent of baseline body mass index in both cohorts, and were not related to other demographic and asthma risk factors nor other tested markers of systemic inflammation and metabolic syndrome.

CONCLUSIONS

In 2 separate birth cohorts, higher blood insulin level in early childhood was associated with increased risk of active asthma through adolescence and adulthood, independent of body mass index. High insulin indicates a novel mechanism for asthma development, which may be a target for intervention.

Changes in the Expression of Insulin Pathway, Neutrophil Elastase and Alpha 1 Antitrypsin Genes from Leukocytes of Young Individuals with Insulin Resistance

BACKGROUND

Chronic hyperinsulinemia is a hallmark of insulin resistance that affects a diversity of cells, including leukocytes modifying the expression of some genes involved in insulin signaling.

PURPOSE

The aim of this study was to evaluate how hyperinsulinemia affects the expression of genes involved in the proximal insulin signaling pathway in leukocytes from 45 young individuals grouped: normal weight with not insulin resistance (NIR), with insulin resistance (IR) and with obesity (OB-IR).

METHODS

qPCR was performed to analyze the expression of insulin receptor (INSR), insulin receptor substrate 1 and 2 (IRS-1 and IRS-2), neutrophil elastase (NE), alpha 1 antitrypsin (A1AT), glucose transporters 1, 3 and 4 (GLUT-1, GLUT-3 and GLUT-4) by the 2^-ΔCt method, and the correlation between the genes was determined by Spearman's test.

RESULTS

The mRNA expression analysis of all genes between NIR and IR individuals revealed no differences. However, when comparing NIR and IR individuals with OB-IR, an increase in NE and A1AT expression and a clear trend towards a decrease in IRS-2 expression was observed, whereas the comparison of IR and OB-IR showed a decrease in GLUT-3 expression. Overall, the correlation analysis showed that in the IR group there was a positive correlation only between NE with IRS-1 (r = 0.72, p = 0.003), while in the OB-IR group, there was a positive correlation between the NE and A1AT with INSR (r = 0.62, p = 0.01 and r = 0.74, p = 0.002, respectively) and with IRS-2 (r = 0.74, p = 0.002 and r = 0.76, p = 0.001, respectively).

CONCLUSION

These results suggest that hyperinsulinemia and obesity are associated with changes in the expression of genes in leukocytes involved in the insulin pathway that are related to NE and A1AT.

Nonrespiratory Comorbidities in Asthma

Asthma is a chronic heterogeneous airway disease. Common comorbid conditions are often disproportionately present in severe asthma. Optimal care of patients with asthma requires the recognition and treatment of these comorbid conditions. This review outlines the pathophysiological mechanisms between nonrespiratory comorbid conditions and asthma and their effect on asthma outcomes. They include: type 2 diabetes mellitus, hypertension, atherosclerotic cardiovascular disease, adrenal and thyroid gland diseases, pregnancy, osteoporosis, adverse effects from medications, and mental health disorders. Studies indicate how poor glycemic control of type 2 diabetes mellitus is associated with not only greater health care utilization but poorer asthma outcomes. Also, a large health care claims database indicates that a substantial proportion of pregnant women have uncontrolled asthma and are prescribed suboptimal controller therapy. Additional data about these nonrespiratory comorbidities and medications known to benefit both nonrespiratory comorbidities and asthma are necessary.

Nutrition, Obesity and Asthma Inception in Children. The Role of Lung Function

Obesity is an important public health problem. WHO estimates that about 39 million children younger than 5 years of age are overweighted or obese. On the other hand, asthma is the most prevalent chronic disease in childhood, and thus, many children share those two conditions. In the present paper we review the epidemiology of children with asthma and obesity, as well as the consequences of being obese on the respiratory system. On the one hand obesity produces an underlying T-helper 2 (TH2) low inflammation state in which numerous cytokines, which could have an impact in the respiratory system play, a role. On the other hand, some respiratory changes have been described in obese children and, specially, the development of the so called “dysanapsis” (the disproportionate scaling of airway dimensions to lung volume) which seems to be common during the first stages of life, probably related to the early development of this condition. Finally, this review deals with the role of adipokines and insulin resistance in the inception and worsening of asthma in the obese child.

Insulin resistance-related differences in the relationship between left ventricular hypertrophy and cardiorespiratory fitness in hypertensive Black sub-Saharan Africans

BACKGROUND

Left ventricular hypertrophy (LVH) is associated with impaired cardiorespiratory fitness (CRF), a surrogate marker of poor outcome. Insulin resistance (IR) plays a central role in all stages of cardiovascular disease continuum. This study evaluates IR-related differences in the relationship between left ventricular mass (LVM) and CRF in asymptomatic newly diagnosed hypertensive Black sub-Saharan Africans.

METHODS

In this cross-sectional observational study, 126 asymptomatic newly diagnosed hypertensive participants (50.5 ± 9.5 years) underwent comprehensive resting transthoracic echocardiographic examination and maximal incremental cardiopulmonary exercise test (CPET). CRF was estimated in maximal oxygen uptake (VO2max). CPET results were compared between participants with and without LVH. Multivariate analysis examined the influence of IR on the observed differences.

RESULTS

Those with LVH had lower VO2max (15.7 ± 5.5 mL min^-1 kg^-1 vs. 18.4 ± 3.7 mL min^-1 kg^-1; P = 0.001) than those without LVH. In patients with IR, LVM (r = -0.261, P = 0.012), LVM indexed to body surface area (LVMIbsa; r = -0.229, P = 0.027), and LVM indexed to height to an allometric power of 2.7 (LVMIh^2.7; r = -0.351, P = 0.001), and VO2max were negatively correlated. In hypertensive patients without IR, these same parameters and VO2max have no significant correlation. Body mass index (BMI), LVM, and LVMIbsa emerged as independent determinants of VO2max, explaining 46.9% of its variability (overall P = 0.001) in IR participants, a relationship not found in participants without IR.

CONCLUSIONS

IR may participate in the deterioration of CRF associated with LVH. Measures to improve insulin sensitivity should be considered for improving CRF and therefore the prognosis of insulin-resistant hypertensive patients. Targeting IR in hypertensive patients with LVH could improve prognosis.

Pediatric Obesity-Related Asthma: The Role of Nutrition and Nutrients in Prevention and Treatment

Childhood obesity rates have dramatically risen in numerous countries worldwide. Obesity is likely a factor in increased asthma risk, which is already one of the most widespread chronic respiratory pathologies. The pathogenic mechanism of asthma risk has still not yet been fully elucidated. Moreover, the role of obesity-related inflammation and pulmonary overreaction to environmental triggers, which ultimately result in asthma-like symptoms, and the importance of dietary characteristics is well recognized. Diet is an important adjustable element in the asthma development. Food-specific composition of the diet, in particular fat, sugar, and low-quality nutrients, is likely to promote the chronic inflammatory state seen in asthmatic patients with obesity. An unbalanced diet or supplementation as a way to control asthma more efficiently has been described. A personalized dietary intervention may improve respiratory symptoms and signs and therapeutic response. In this narrative review, we presented and discussed more recent literature on asthma associated with obesity among children, focusing on the risk of asthma among children with obesity, asthma as a result of obesity focusing on the role of adipose tissue as a mediator of systemic and local airway inflammation implicated in asthma regulation, and the impact of nutrition and nutrients in the development and treatment of asthma. Appropriate early nutritional intervention could possibly be critical in preventing and managing asthma associated with obesity among children.

Association of Pulmonary Function Decline over Time with Longitudinal Change of Glycated Hemoglobin in Participants without Diabetes Mellitus

Pulmonary damage and function impairment were frequently noted in patients with diabetes mellitus (DM). However, the relationship between lung function and glycemic status in non-DM subjects was not well-known. Here, we evaluated the association of longitudinal changes of lung function parameters with longitudinal changes of glycated hemoglobin (HbA1c) in non-DM participants. The study enrolled participants without prior type 2 DM, hypertension, and chronic obstructive pulmonary disease (COPD) from the Taiwan Biobank database. Laboratory profiles and pulmonary function parameters, including forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), were examined at baseline and follow-up. Finally, 7055 participants were selected in this study. During a mean 3.9-year follow-up, FVC and FEV1 were significantly decreased over time (both p < 0.001). In the multivariable analysis, the baseline (unstandardized coefficient β = −0.032, p < 0.001) and longitudinal change (unstandardized coefficient β = −0.025, p = 0.026) of FVC were negatively associated with the baseline and longitudinal change of HbA1c, respectively. Additionally, the longitudinal change of FVC was negatively associated with the risk of newly diagnosed type 2 DM (p = 0.018). During a mean 3.9-year follow-up, our present study, including participants without type 2 DM, hypertension, and COPD, demonstrated that the baseline and longitudinal change of FVC were negatively and respectively correlated with the baseline and longitudinal change of HbA1c. Furthermore, compared to those without new-onset DM, participants with new-onset DM had a more pronounced decline of FVC over time.

Cardio-metabolic risk factors during childhood in relation to lung function and asthma

BACKGROUND

Cardio-metabolic risk factors might have an adverse effect on respiratory outcomes, but associations in children are unknown. We aimed to study the longitudinal associations of cardio-metabolic risk factors with lung function and asthma at school age. We also examined whether any association was explained by child's body mass index (BMI).

METHODS

In a population-based cohort study among 4988 children, cardio-metabolic risk factors were measured at 6 and 10 years and included blood pressure, cholesterol, triglycerides, insulin, and C-reactive protein (CRP) concentrations. At age 10 years, lung function was measured by spirometry and current physician-diagnosed asthma was assessed by questionnaire.

RESULTS

After adjustment for confounders, child's BMI, and multiple testing, we observed that a higher diastolic blood pressure at the age of 6 years was associated with a higher forced vital capacity (FVC) at the age of 10 years (Z-score difference (95% CI): 0.05 (0.01, 0.08), per SDS increase in diastolic blood pressure). Also, child's CRP concentrations above the 75th percentile at both ages 6 and 10 years were related to a lower FVC as compared to CRP concentrations below the 75th percentile at both ages (Z-score difference (95% CI) -0.21 (-0.36, -0.06)). No consistent associations of other cardio-metabolic risk factors with respiratory outcomes were observed.

CONCLUSION

Blood pressure and CRP, but not lipids and insulin, were associated with lower lung function but not with asthma. The underlying mechanisms and long-term effects of these associations require further investigation.

Asthmatic Eosinophils Promote Contractility and Migration of Airway Smooth Muscle Cells and Pulmonary Fibroblasts In Vitro

Enhanced contractility and migration of airway smooth muscle cells (ASMC) and pulmonary fibroblasts (PF) are part of airway remodeling in asthma. Eosinophils are the central inflammatory cells that participate in airway inflammation. However, the role of asthmatic eosinophils in ASMC and PF contractility, migration, and differentiation to contractile phenotype has not yet been precisely described. A total of 38 individuals were included in this study: 13 steroid-free non-severe allergic asthma (AA) patients, 11 severe non-allergic eosinophilic asthma (SNEA) patients, and 14 healthy subjects (HS). For AA patients and HS groups, a bronchial allergen challenge with D. pteronyssinus was performed. Individual combined cell cultures were prepared from isolated peripheral blood eosinophils and immortalized ASMC or commercial PF cell lines separately. The migration of ASMC and PF was evaluated using wound healing assay and contractility using collagen gel assay. Gene expression of contractile apparatus proteins, COL1A1, COL5A1, and FN, in ASMC and PF was evaluated using qRT-PCR. We found that contractility and migration of ASMC and PF significantly increased after incubation with asthmatic eosinophils compared to HS eosinophils, p < 0.05, and SNEA eosinophils demonstrated the highest effect on contractility of ASMC and migration of both cell lines, p < 0.05. AA and SNEA eosinophils significantly increased gene expression of contractile apparatus proteins, COL1A1 and FN, in both cell lines, p < 0.05. Furthermore, the allergen-activated AA eosinophils significantly increased the contractility of ASMC, and migration and gene expression in ASMC and PF, p < 0.05. Thus, asthmatic eosinophils change ASMC and PF behavior by increasing their contractility and migration, contributing to airway remodeling.

Silencing a disintegrin and metalloproteinase‑33 attenuates the proliferation of vascular smooth muscle cells via PI3K/AKT pathway: Implications in the pathogenesis of airway vascular remodeling

Accumulating evidence suggests that pulmonary expression of a disintegrin and metalloproteinase-33 (ADAM33) serves a key role in the pathogenesis of airway remodeling-related diseases, including asthma. Airway vascular proliferation has been recognized as a key feature of airway remodeling. Our previous study showed that ADAM33 is constitutively expressed in airway vascular smooth muscle cells in patients with asthma, suggesting a potential role of ADAM33 in regulating airway vascular remodeling. Using in vitro human aortic smooth muscle cells (HASMCs) and lentiviral vector carrying short hairpin RNA for ADAM33, the present study aimed to evaluate the influence of ADAM33 silencing on the proliferation and apoptosis of HASMCs and the underlying molecular pathways. Cellular proliferation was observed using the Cell Counting Kit-8 method. Cellular apoptosis was evaluated with Annexin V-PE/7-AAD staining and flow cytometry. Reverse transcription-quantitative PCR and western blotting were used to evaluate the changes in mRNA and protein levels of involved signaling molecules. It was found that silencing of ADAM33 expression in HASMCs significantly inhibited proliferation, but induced the apoptosis of HASMCs. These changes were accompanied by inhibition of the PI3K/AKT/ERK pathway and Bcl-2, but an increase in Bax expression. These results suggested that constitutive expression of ADAM33 may be important to maintain a proliferative phenotype in HASMCs. The influences of ADAM33 on proliferation and apoptosis of HASMCs may involve regulation of PI3K/AKT/ERK and Bax/Bcl-2 pathways. These findings suggested an important role of ADAM33 in airway vascular remodeling and potential therapeutic significance of ADAM33 inhibition in airway remodeling-related diseases.

T2-"Low" Asthma: Overview and Management Strategies

Although the term "asthma" has been applied to all patients with airway lability and variable chest symptoms for centuries, phenotypes of asthma with distinct clinical and molecular features that may warrant different treatment approaches are well recognized. Patients with type 2 (T2)-"high" asthma are characterized by upregulation of T2 immune pathways (ie, IL-4 and IL-13 gene sets) and eosinophilic airway inflammation, whereas these features are absent in patients with T2-"low" asthma and may contribute to poor responsiveness to corticosteroid treatment. This review details definitions and clinical features of T2-"low" asthma, potential mechanisms and metabolic aspects, pediatric considerations, and potential treatment approaches. Priority research questions for T2-"low" asthma are also discussed.

[Change in the expression of gene transcription negative regulator SOCS1 in the patients with bronchial asthma and metabolic disorders]

AIM

Comprehensive study of the negative regulation components of cell signaling in the bronchial asthma (BA) patients with metabolic disorders.

MATERIALS AND METHODS

113 people were examined: 63 patients with allergic BA (ABA), 50 patients with a non-allergic variant of the disease (NABA). SOCS1 mRNA expression was evaluated by reverse transcription PCR (RT-PCR). SOCS1 protein expression was investigated by immunoblotting. The determination of cytokine levels was carried out according to the standard protocol on a Bio-Plex flow fluorimeter.

RESULTS

A significant and multidirectional change in the expression of SOCS1 mRNA was found at a body mass index 25 (greater than normal) in ABA and NABA. The positive correlations between SOCS1 mRNA expression and body mass index indicate the regulatory role of SOCS1 in leptin signaling. The spectra of correlations in ABA and NABA are different, it indicates the probable existence of specificity in the pathogenesis of these variants of the diseases.

CONCLUSION

The obtained data allow us to consider the complexity of regulation disorders occurring at different levels of cell signaling. The multifunctionality of the SOCS1 regulator provides complex control of cytokine signaling simultaneously in different signaling pathways in the BA with metabolic disorders.

Glucagon-like peptide-1 (GLP-1) improved diabetic lung fibrosis via AMPK and microRNA-27a (miR-27a)

Background

Extracellular matrix proliferation is an issue which leads to lung tissue damage in diabetes mellitus. Glucagon-like peptide-1 (GLP-1) analogues can improve the proliferation of extracellular matrix in diabetic pulmonary disease. In this study, we investigated the effect of GLP-1 on pulmonary fibrosis through the AMPK/microRNA-27a (miR-27a) pathway.

Methods

Human embryonic lung fibroblast (MRC-5) cells were cultured with a high-glucose medium, and were treated with miR-27a inhibitor, GLP-1 analogues, and AMPK inhibitor. Cell Counting Kit-8 (CCK-8) detected the proliferation of MRC-5 cells. The fibrosis-related genes were analyzed, including Col-IV, fibronectin, NF-κB p65, α-SMA, and TGF-β1. Bioinformatics and dual-luciferase reporter assays were used to identify the targets for miR-27a.

Results

Compared with the control group, the expression of miR-27a in the hyperglycemic group was significantly up-regulated (P<0.01) and the expression of peroxisome proliferator-activated receptor γ (PPARγ) significantly down-regulated (P<0.01). The expression of Col-IV, fibronectin, NF-κB p65, α-SMA and TGF-β1 increased significantly (P<0.01). The expression level of apoptosis factor caspase-3 decreased significantly (P<0.01). MiR-27a inhibitor could reverse the expression of these proteins. The effect of GLP-1 on miR-27a was time- and concentration-dependent. After pretreating MRC-5 cells via GLP-1, with or without compound C (AMPK inhibitor), the expression of miR-27a in the GLP-1 treated group was significantly lower than that in Vehicle group. The expression of miR-27a was increased after inhibition of the AMPK pathway. A predictive TargetScan algorithm showed that the PPARγ gene was a potential target of miR-27a. MiR-27a was also shown to target 3'-UTR of PPARγ.

Conclusions

MiR-27a plays an important regulatory role in diabetic pulmonary fibrosis. GLP-1 could down-regulate the expression level of miR-27a by activating AMPK. Furthermore, the target gene PPARγ was up-regulated, consequently improving extracellular matrix proliferation in MRC-5 cells.

Novel Aspects of Insulin-like Growth Factor 1/insulin Network in Chronic Inflammatory Airway Disease

At least a proportion of patients suffering from chronic inflammatory airway diseases respond poorly to the bronchodilator and corticosteroid therapies. There is a need for the development of improved anti-inflammatory treatment. Insulin Growth Factor 1 (IGF1) and insulin participate in not only metabolism and glucose homeostasis, but also many other physiological and pathophysiological processes, including growth and inflammation. Recently, it was shown that not only the classical IGF1 and IGF1 Receptor (IGF1R), but also the other molecules in the IGF1/insulin network, including insulin, insulin-like growth factor-binding protein (IGFBP), and IGFBP protease, have roles in chronic inflammatory airway diseases. This review aims to provide a comprehensive insight into recent endeavors devoted to the role of the IGF1/insulin network in chronic inflammatory airway diseases. Its participation in airway inflammation, remodeling, and hyper-responsiveness (AHR), as well as acute exacerbation, has been conclusively demonstrated. Its possible relation to glucocorticoid insensitivity has also been indicated. A better understanding of the IGF1/insulin network by further bench-to-bedside research may provide us with rational clinical therapeutic approaches against chronic inflammatory airway diseases.

Association between Asthma and Type 2 Diabetes Mellitus: Mechanisms and Impact on Asthma Control-A Literature Review

The study aimed to analyze the scientific production on the association between asthma and type 2 diabetes mellitus (T2DM) in adults, the mechanisms that explain this association, and its impact on asthma control. A literature review of scientific articles indexed in the MEDLINE/PUBMED, BVS, CINAHL, Cochrane Library, and Web of Science databases was carried out, considering publications from January 2009 to December 2019, using the following descriptors: "asthma", "type 2 diabetes", "adult," and "association". Of 962 articles found, 18 were included because they met the eligibility criteria. It is suggested that the association between asthma and T2DM is caused by low-grade systemic inflammation (7 articles) or the use of corticosteroids (7 articles). It is noticed that there is a limited scientific production regarding the consequences of this association for the control of asthma (5 articles). It is concluded that asthma and T2DM are two common chronic conditions of increasing prevalence and that often coexist in the same patient. It is suggested that this coexistence worsens asthma control. Therefore, the study may support public policies and clinical health practices that value the approach of comorbidities associated with asthma such as T2DM, in order to minimize additional health risks and reduce the quality of life.

Genetic Correlation and Bidirectional Causal Association Between Type 2 Diabetes and Pulmonary Function

BACKGROUND

Observational studies have shown possible bidirectional association between type 2 diabetes (T2D) and pulmonary function, but the causality is not well defined. The purpose of this study is to investigate genetic correlation and causal relationship of T2D and glycemic traits with pulmonary function.

METHODS

By leveraging summary statistics from large-scale genome-wide association studies, linkage disequilibrium score regression was first implemented to quantify genetic correlations between T2D, glycemic traits, and several spirometry indices. Then both univariable and multivariable Mendelian randomization analyses along with multiple pleiotropy-robust methods were performed in two directions to assess the causal nature of these relationships.

RESULTS

Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) showed significant genetic correlations with T2D and fasting insulin levels and suggestive genetic correlations with fasting glucose and hemoglobin A1c. In Mendelian randomization analyses, genetically predicted higher FEV1 (OR = 0.77; 95% CI = 0.63, 0.94) and FVC (OR = 0.82; 95% CI = 0.68, 0.99) were significantly associated with lower risk of T2D. Conversely, genetic predisposition to higher risk of T2D exhibited strong association with reduced FEV1 (beta = -0.062; 95% CI = -0.100, -0.024) and FEV1 (beta = -0.088; 95% CI = -0.126, -0.050) and increased FEV1/FVC ratio (beta = 0.045; 95% CI = 0.012, 0.078). We also found a suggestive causal effect of fasting glucose on pulmonary function and of pulmonary function on fasting insulin and proinsulin.

CONCLUSIONS

The present study provided supportive evidence for genetic correlation and bidirectional causal association between T2D and pulmonary function. Further studies are warranted to clarify possible mechanisms related to lung dysfunction and T2D, thus offering a new strategy for the management of the two comorbid diseases.

Obesity and diabetes: similar respiratory mechanical but different gas exchange defects

Diabetes mellitus increases smooth muscle tone and causes tissue remodeling, affecting elastin and collagen. Although the lung is dominated by these elements, diabetes is expected to modify the airway function and respiratory tissue mechanics. Therefore, we characterized the respiratory function in patients with diabetes with and without associated obesity. Mechanically ventilated patients with normal body shapes were divided into the control nondiabetic (n = 73) and diabetic (n = 31) groups. The other two groups included obese patients without diabetes (n = 43) or with diabetes (n = 30). The mechanical properties of the respiratory system were determined by forced oscillation technique. Airway resistance (Raw), tissue damping (G), and tissue elastance (H) were assessed by forced oscillation. Capnography was applied to determine phase 3 slopes and dead space indices. The intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (Pa_O2/FI_O2) were estimated from arterial and central venous blood samples. Compared with the corresponding control groups, diabetes alone increased the Raw (7.6 ± 6 cmH₂O.s/l vs. 3.1 ± 1.9 cmH₂O.s/l), G (11.7 ± 5.5 cmH₂O/l vs. 6.5 ± 2.8 cmH₂O/l), and H (31.5 ± 11.8 cmH₂O/l vs. 24.2 ± 7.2 cmH₂O/l (P < 0.001 for all). Diabetes increased the capnographic phase 3 slope, whereas Pa_O2/FI_O2 or Qs/Qt was not affected. Obesity alone caused similar detrimental changes in respiratory mechanics and alveolar heterogeneity, but these alterations also compromised gas exchange. We conclude that diabetes-induced intrinsic mechanical abnormalities are counterbalanced by hypoxic pulmonary vasoconstriction, which maintained intrapulmonary shunt fraction and oxygenation ability of the lungs.

Metabolic Dysfunction and Asthma: Current Perspectives

The increasing knowledge of the mechanisms involved in metabolism is shifting the paradigms by which the pathophysiology of many pulmonary diseases is understood. Metabolic dysfunction is recognized in obesity-associated asthma, but other metabolic conditions have been shown to be independently related to asthma. Novel insights have also recently been brought by metabolomics in this filed. The purpose of this review is to discuss current perspectives regarding metabolic dysfunction in asthma, from obesity-related asthma to other metabolic conditions and the role of current pharmacological therapeutic strategies and lifestyle interventions. Obesity is a well-recognized risk factor for asthma across the lifespan, which is generally associated with poorer response to current available treatments, rendering a more severe, refractory disease status. Besides the epidemiological and clinical link, untargeted metabolomics studies have recently supported the obesity-associated asthma phenotype at the molecular level. Not only obesity-related, but also other aspects of metabolic dysregulation can be independently linked to asthma. These include hyperinsulinemia, dyslipidemia and hypertension, which need to be taken into account, even in the non-obese patient. Untargeted metabolomics studies have further highlighted several other metabolic pathways that can be altered in asthma, namely regarding oxidative stress and systemic inflammation, and also suggesting the importance of microbiota in asthma pathogenesis. Considering the reduced response to corticosteroids, other pharmacologic treatments have been shown to be effective regardless of body mass index. Non-pharmacologic treatments (namely weight reduction and dietary changes) may bring substantial benefit to the asthmatic patient. Taken together, this evidence points towards the need to improve our knowledge in this filed and, in particular, to address the influence of environmental factors in metabolic dysfunction and asthma development. Personalized medicine is definitely needed to optimize treatment, including a holistic view of the asthmatic patient in order to set accurate pharmacologic therapy together with dietary, physical exercise and lifestyle interventions.

Insulin sensitivity in long-lived growth hormone-releasing hormone knockout mice

Our previous studies showed that loss-of-function mutation of growth hormone releasing hormone (GHRH) results in increased longevity and enhanced insulin sensitivity in mice. However, the details of improved insulin action and tissue-specific insulin signaling are largely unknown in this healthy-aging mouse model. We conducted hyperinsulinemic-euglycemic clamp to investigate mechanisms underlying enhanced insulin sensitivity in growth hormone (GH) deficient mice. Further, we assessed in vivo tissue-specific insulin activity via activation of PI3K-AKT and MAPK-ERK1/2 cascades using western blot. Clamp results showed that the glucose infusion rate required for maintaining euglycemia was much higher in GHRH^-/- mice compared to WT controls. Insulin-mediated glucose production was largely suppressed, whereas glucose uptake in skeletal muscle and brown adipose tissue were significant enhanced in GHRH^-/- mice compared to WT controls. Enhanced capacity of insulin-induced activation of the PI3K-AKT and MAPK-ERK1/2 signaling were observed in a tissue-specific manner in GHRH^-/- mice. Enhanced systemic insulin sensitivity in long-lived GHRH^-/- mice is associated with differential activation of insulin signaling cascades among various organs. Improved action of insulin in the insulin sensitive tissues is likely to mediate the prolonged longevity and healthy-aging effects of GH deficiency in mice.

Glycated Hemoglobin A1c, Lung Function, and Hospitalizations Among Adults with Asthma

BACKGROUND

Insulin resistance and metabolic dysfunction have been associated with asthma risk and asthma severity.

OBJECTIVE

To examine the association between glycated hemoglobin A_1c (HbA_1c), asthma-related hospitalizations, and lung function measures among adults in the United Kingdom.

METHODS

A cross-sectional study was conducted of 47,606 adults aged 40 to 69 years who participated in the UK Biobank and had asthma but no diagnosis of diabetes mellitus. HbA_1c level was analyzed as a continuous measure and also categorized as normal (<42 mmol/mol) or as consistent with prediabetes/diabetes (≥42 mmol/mol). An asthma-related hospitalization was defined as ever having had a hospitalization with an International Classification of Diseases, Ninth/Tenth Revision, Clinical Modification code of a main diagnosis compatible with asthma (International Classification of Diseases, Ninth Revision, Clinical Modification code 493.x or International Classification of Diseases, Tenth Revision, Clinical Modification codes J45.x and J46.x). Logistic or linear regression was used for the multivariable analysis of asthma hospitalizations and lung function measures (FEV₁, forced vital capacity [FVC], and FEV₁/FVC). All models were adjusted for age, sex, ethnic background, body mass index, average annual household income, current smoking status, pack-years of smoking, fasting time, and C-reactive protein level.

RESULTS

Both HbA_1c level (odds ratio, 1.03; 95% CI, 1.01-1.04) and an HbA_1c level in the prediabetes/diabetes range (odds ratio, 1.68; 95% CI, 1.18-2.41) were associated with 1 or more asthma hospitalizations. Moreover, both HbA_1c level and an HbA_1c level in the prediabetes/diabetes range were significantly and inversely associated with FEV₁ and FVC.

CONCLUSIONS

HbA_1c is linked to asthma-related hospitalizations and small decrements in FEV₁ and FVC among British adults with asthma but no diagnosis of diabetes mellitus.

Effect of Subcutaneous Insulin on Spirometric Maneuvers in Patients with Type 1 Diabetes: A Case-Control Study

In order to compare spirometric maneuvers in adults according to the presence of type 1 diabetes, a case-control study including 75 patients with type 1 diabetes and 75 controls matched by sex, age, and body mass index were designed. In addition, 75 patients with type 1 diabetes were added to examine the potential the impact of subcutaneous insulin therapy on pulmonary function. Lung function measurements were assessed according to the global initiative for chronic obstructive lung disease guidelines. Basal insulin included long-acting insulin analogues and the delivered background insulin in patients with pump therapy. Bolus insulin included rapid-acting insulin analogues and the delivered insulin to cover postprandial hyperglycemias. Patients with type 1 diabetes showed lower spirometric values in comparison to the control group, together with a higher prevalence of forced expiratory volume in the first second (FEV1) <80% (10.7% vs. 2.7%, p = 0.044) and restrictive ventilatory pattern (10.7% vs. 0%, p = 0.006) The dose of basal insulin (U/kg/day) showed a negative correlation with forced vital capacity (FVC) (r = −0.205, p = 0.012) and FEV1 (r = −0.182, p = 0.026). The optimal cut-off value for identifying patients with a restrictive spirometric pattern was 0.5 U/kg/day of basal insulin. Additionally, basal insulin (U/kg/day) independently predicted the presence of both a restrictive spirometric pattern (OR = 77.1 (3.2 to 1816.6), p = 0.007) and an abnormal FEV1 (OR = 29.9 (1.5 to 562.8), p = 0.023). In patients with type 1 diabetes, higher basal insulin dosage seems to be related with an impairment of pulmonary function.

Preserving Airway Smooth Muscle Contraction in Precision-Cut Lung Slices

Precision-cut lung slices (PCLS) are ideal for measuring small airway contraction. However, these measurements are currently limited to acute exposure scenarios that typically last a few minutes to a few hours. Using an insulin-supplemented culture medium, we prolong the small airway contractility in mouse PCLS for up to two weeks. Compared to conventional culture medium, insulin-supplemented culture medium provides no additional benefit in preserving cellular viability or airway structure. However, it protects the airway smooth muscle (ASM) against a loss of smooth muscle myosin heavy chain (SMMHC) expression. We elucidate the significance of this new culture medium for chronic disease modeling of IL-13-induced airway hyper-responsiveness.

Lung volume dependence of respiratory function in rodent models of diabetes mellitus

Background

Diabetes mellitus causes the deterioration of smooth muscle cells and interstitial matrix proteins, including collagen. Collagen and smooth muscle cells are abundant in the lungs, but the effect of diabetes on airway function and viscoelastic respiratory tissue mechanics has not been characterized. This study investigated the impact of diabetes on respiratory function, bronchial responsiveness, and gas exchange parameters.

Methods

Rats were allocated randomly to three groups: a model of type 1 diabetes that received a high dose of streptozotocin (DM1, n = 13); a model of type 2 diabetes that received a low dose of streptozotocin with a high-fat diet (DM2, n = 14); and a control group with no treatment (C, n = 14). Forced oscillations were applied to assess airway resistance (Raw), respiratory tissue damping (G), and elastance (H). The arterial partial pressure of oxygen to the inspired oxygen fraction (PaO₂/FiO₂) and intrapulmonary shunt fraction (Qs/Qt) were determined from blood gas samples at positive end-expiratory pressures (PEEPs) of 0, 3, and 6 cmH₂O. Lung responsiveness to methacholine was also assessed. Collagen fibers in lung tissue were quantified by histology.

Results

The rats in groups DM1 and DM2 exhibited elevated Raw, G, H, and Qs/Qt, compromised PaO₂/FiO₂, and diminished airway responsiveness. The severity of adverse tissue mechanical change correlated with excessive lung collagen expression. Increased PEEP normalized the respiratory mechanics, but the gas exchange abnormalities remained.

Conclusions

These findings indicate that diabetes reduces airway and lung tissue viscoelasticity, resulting in alveolar collapsibility that can be compensated by increasing PEEP. Diabetes also induces persistent alveolo-capillary dysfunction and abnormal adaptation ability of the airways to exogenous constrictor stimuli.

Downregulated level of insulin in COPD patients during AE; role beyond glucose control?

Objective

The purpose of this study was to explore the insulin level in the serum of chronic obstructive pulmonary disease (COPD) patients during acute exacerbation (AE).

Methods

The study population consisted of 22 acute exacerbation chronic obstructive pulmonary disease (AECOPD) patients, 20 COPD patients and 20 healthy controls. Fasting blood glucose, insulin and serum lipid levels were measured. After the patients recovered from AE, the insulin and glucose levels were also analyzed.

Results

Insulin level, glucose level and homeostasis model assessment of insulin resistance (HOMA-IR) of AECOPD patients were higher than healthy controls (7.19±6.02 vs 3.28±1.09 μIU/mL, P<0.05, 126.61±50.92 vs 96.21±12.66 mg/dL, P<0.05, 2.66±2.72 vs 0.78±0.26, P<0.05). For stable COPD patients, the insulin level, glucose level and HOMA-IR were 6.52±2.56 μIU/mL, 95.58±11.44 mg/dL, and 1.52±0.53, respectively. The triglyceride (TG) level, total cholesterol (CHOL) level and low-density lipoprotein cholesterol (LDL-CHOL) level were decreased in AECOPD patients (0.78±0.33 vs 1.05±0.35 mmol/L, P<0.05, 3.88±0.72 vs 4.49±0.7 mmol/L, P<0.05, 2.01±0.59 vs 2.59±0.58 mmol/L, P<0.05). When the patients had recovered from AE, the insulin levels increased (10.67±6.22 vs 7.12±6.19 μIU/mL, P<0.05) and the glucose levels decreased (122.69±41.41 vs 134.08±53.19 mg/dL, P>0.05).

Conclusion

A high insulin level and a high HOMA-IR status in COPD patients were demonstrated. Downregulated levels of insulin during AE compared with the convalescent state were detected, while the variation in the glucose level was not as great as expected, indicating a potentially important role for insulin in AECOPD.

Empagliflozin and Dulaglutide are Effective against Obesity-induced Airway Hyperresponsiveness and Fibrosis in A Murine Model

Patients with asthma with obesity experience severe symptoms, are unresponsive to conventional asthma treatment, and lack proper pharmacotherapy. Empagliflozin and dulaglutide, developed for diabetes, reduce weight, decrease insulin resistance, and exert additive effects. We evaluated the efficacy of empagliflozin, dulaglutide, and their combination on obesity-induced airway hyperresponsiveness (AHR) and lung fibrosis using a murine model. We assigned C57BL/6J mice to five groups: control, high-fat diet (HFD), and HFD with empagliflozin, dulaglutide, or both. Mice received a 12-week HFD, empagliflozin (5 days/week, oral gavage), and dulaglutide (once weekly, intraperitoneally). Both drugs significantly attenuated HFD-induced weight increase, abnormal glucose metabolism, and abnormal serum levels of leptin and insulin, and co-treatment was more effective. Both drugs significantly alleviated HFD-induced AHR, increased macrophages in bronchoalveolar lavage fluid (BALF), and co-treatment was more effective on AHR. HFD-induced lung fibrosis was decreased by both drugs alone and combined. HFD induced interleukin (IL)-17, transforming growth factor (TGF)-β1, and IL-1β mRNA and protein expression, which was significantly reduced by empagliflozin, dulaglutide, and their combination. Tumour necrosis factor (TNF)-α and IL-6 showed similar patterns without significant differences. HFD-enhanced T helper (Th) 1 and Th17 cell differentiation was improved by both drugs. Empagliflozin and dulaglutide could be a promising therapy for obesity-induced asthma and showed additive effects in combination.

Association of pediatric obesity and asthma, pulmonary physiology, metabolic dysregulation, and atopy; and the role of weight management

Introduction: Obesity affects about 40% of US adults and 18% of children. Its impact on the pulmonary system is best described for asthma. Areas covered: We reviewed the literature on PubMed and Google Scholar databases and summarize the effect of obesity, its associated metabolic dysregulation and altered systemic immune responses, and that of weight gain and loss on pulmonary mechanics, asthma inception, and disease burden. We include a distinct approach for diagnosing and managing the disease, including pulmonary function deficits inherent to obesity-related asthma, in light of its poor response to current asthma medications. Expert opinion: Given the projected increase in obesity, obesity-related asthma needs to be addressed now. Research on the contribution of metabolic abnormalities and systemic immune responses, intricately linked with truncal adiposity, and that of lack of atopy, to asthma disease burden, and pulmonary function deficits among obese children is fairly consistent. Since current asthma medications are more effective for atopic asthma, investigation for atopy will guide management by distinguishing asthma responsive to current medications from the non-responsive disease. Future research is needed to elucidate mechanisms by which obesity-mediated metabolic abnormalities and immune responses cause medication non-responsive asthma, which will inform repurposing of medications and drug discovery.

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.

Lung function measurements in the prediabetes stage: data from the ILERVAS Project

AIMS

Patients with type 2 diabetes have been considered a susceptible group for pulmonary dysfunction. Our aim was to assess pulmonary function on the prediabetes stage.

METHODS

Pulmonary function was assessed in 4,459 non-diabetic subjects, aged between 45 and 70 years, without cardiovascular disease or chronic pulmonary obstructive disease from the ongoing study ILERVAS. A "restrictive spirometric pattern", an "abnormal FEV1" and an "obstructive ventilatory defect" were assessed. Prediabetes was defined by glycosylated hemoglobin (HbA1c) between 5.7 and 6.4% according to the American Diabetes Association criteria.

RESULTS

Population was composed of 52.1% women, aged 57 [53;63] years, a BMI of 28.6 [25.8;31.8] kg/m², and with a prevalence of prediabetes of 29.9% (n = 1392). Subjects with prediabetes had lower forced vital capacity (FVC: 93 [82;105] vs. 96 [84;106], p < 0.001) and lower forced expired volume in the first second (FEV1: 94 [82;107] vs. 96 [84;108], p = 0.011), as well as a higher percentage of the restrictive spirometric pattern (16.5% vs. 13.6%, p = 0.015) and FEV1 < 80% (20.3% vs. 17.2%, p = 0.017) compared to non-prediabetes group. In the prediabetes group, HbA1c was negatively correlated with both pulmonary parameters (FVC: r = - 0.113, p < 0.001; FEV1: r = - 0.079, p = 0.003). The multivariable logistic regression model in the whole population showed that there was a significant and independent association between HbA1c with both restrictive spirometric pattern [OR = 1.42 (1.10-1.83), p = 0.008] and FEV1 < 80% [OR = 1.50 (1.19-1.90), p = 0.001].

CONCLUSIONS

The deleterious effect of type 2 diabetes on pulmonary function appears to be initiated in prediabetes, and it is related to metabolic control. TRIAL REGISTRATION CLINICALTRIALS.GOV: NCT03228459.

Insulin resistance mediates high-fat diet-induced pulmonary fibrosis and airway hyperresponsiveness through the TGF-β1 pathway

Prior studies have reported the presence of lung fibrosis and enhanced airway hyperresponsiveness (AHR) in mice with high-fat-diet (HFD)-induced obesity. This study evaluated the role of TGF-β1 in HFD-induced AHR and lung fibrosis in a murine model. We generated HFD-induced obesity mice and performed glucose and insulin tolerance tests. HFD mice with or without ovalbumin sensitization and challenge were also treated with an anti-TGF-β1 neutralizing antibody. AHR to methacholine, inflammatory cells in the bronchoalveolar lavage fluid (BALF), and histological features were evaluated. Insulin was intranasally administered to normal diet (ND) mice, and in vitro insulin stimulation of BEAS-2b cells was performed. HFD-induced obesity mice had increased insulin resistance, enhanced AHR, peribronchial and perivascular fibrosis, and increased numbers of macrophages in the BALF. However, they did not have meaningful eosinophilic or neutrophilic inflammation in the lungs compared with ND mice. The HFD enhanced TGF-β1 expression in the bronchial epithelium, but we found no differences in the expression of interleukin (IL)-4 or IL-5 in lung homogenates. Administration of the anti-TGF-β1 antibody attenuated HFD-induced AHR and lung fibrosis. It also attenuated goblet cell hyperplasia, but did not affect the AHR and inflammatory cell infiltration induced by OVA challenge. The intranasal administration of insulin enhanced TGF-β1 expression in the bronchial epithelium and lung fibrosis. Stimulating BEAS-2b cells with insulin also increased TGF-β1 production by 24 h. We concluded that HFD-induced obesity-associated insulin resistance enhances TGF-β1 expression in the bronchial epithelium, which may play an important role in the development of lung fibrosis and AHR in obesity.

Obesity and severe asthma

Obesity is an important global health issue for both children and adults. Obesity increases the prevalence and incidence of asthma and also increases the risk for severe asthma. Here we describe the features of severe asthma phenotypes for which obesity is a defining characteristic, including steroid resistance, airway inflammation, and co-morbidities. We also review current concepts regarding the mechanistic basis for the impact of obesity in severe asthma, including possible roles for vitamin D deficiency, systemic inflammation, and the microbiome. Finally, we describe data indicating a role for diet, weight loss, and exercise in the treatment of severe asthma with obesity. Better understanding of the mechanistic basis for the role of obesity in severe asthma could lead to new therapeutic options for this population.