Obesity, adipokines, and lung disease

Serum leptin and adiponectin function as indicators of allergic sensitization in pediatric adenotonsillar hypertrophy

PURPOSE

Obesity is commonly linked to both adenotonsillar hypertrophy (ATH) and allergic disorders, in which the roles of adipokines are not fully illuminated. This study aims to investigate the levels of leptin and adiponectin and their associations with allergic sensitization in pediatric ATH.

METHODS

Serum levels of specific immunoglobulin E (IgE), leptin and adiponectin were quantified in 35 controls and 111 ATH children, in which 54 were non-atopic and 57 were atopic. Spearman's correlation analysis and polynomial linear trend test were conducted. The odds ratios and 95% confidence intervals were calculated by binary logistic regression after multivariable adjustment.

RESULTS

The serum level of leptin and leptin/adiponectin (L/A) ratio was significantly increased in children with ATH. An increase in leptin level and L/A ratio and a decrease in adiponectin level were observed in atopic children compared with non-atopic children. Among ATH children, the level of adiponectin was negatively while L/A ratio was positively correlated with specific IgE. After multivariable adjustment, leptin was significantly associated with increased risk of atopy to D. pteronyssinus and D. farina, and adiponectin was significantly associated with decreased risk of atopy to willow and mugwort. Leptin was associated with higher odds while adiponectin was associated with lower odds of overall atopy. Besides, significant multiplicative interactions of obesity with leptin and adiponectin on atopy were observed respectively.

CONCLUSION

Leptin and adiponectin were both associated with allergic sensitization and function differently in pediatric ATH. Mechanistic studies are needed to elucidate the involvement of adipokines in allergic sensitization of pediatric ATH.

Sleeve Gastrectomy is Associated with Longitudinal Improvements in Lung Function and Patient-Reported Respiratory Outcomes

PURPOSE

Obesity exerts negative effects on pulmonary function through proven mechanical and biochemical pathways. Multiple studies have suggested that bariatric surgery can improve lung function. However, the timing of these effects on lung function and its association with patient reported outcomes is not known.

MATERIALS AND METHODS

A prospective cohort study of patients undergoing laparoscopic sleeve gastrectomy (LSG) at a tertiary care hospital was undertaken. Spirometry tests, laboratory tests, and self-reported questionnaires on asthma symptoms and asthma control (ACQ and ACT) were administered. All data were recorded pre-operatively (T0) and every 3 months post-operatively for 1 year (T3, T6, T9, T12) and were compared using a mixed-models approach for repeated measures.

RESULTS

For the 23 participants, mean age was 44.2 ± 12.3 years, mean BMI was 45.2 ± 7.2 kg/m2, 18(78%) were female, 9(39%) self-reported as non-white and 6(26%) reported to have asthma. Following LSG, % total body weight loss was significant at all follow-up points (P < 0.0001). Rapid improvement in forced expiratory volume (FEV)% predicted and forced vital capacity (FVC)% predicted was seen at T3. Although the overall ACQ and ACT score remained within normal range throughout the study, shortness of breath declined significantly at 3 months post-op (P < 0.05) and wheezing resolved for all patients by twelve months. Patients also reported reduced frequency of sleep interruption and inability to exercise by the end of the study (P < 0.05).

CONCLUSION

Improvements in objective lung function assessments and patient-reported respiratory outcomes begin as early as 3 months and continue until 12 months after sleeve gastrectomy.

Can adipokines predict clinical prognosis and post-COVID lung sequelae?

BACKGROUND

Adipokines play an important role in the regulation of inflammatory responses toward infections, including COVID-19. This study aimed to investigate the role of chemerin, adiponectin, and leptin in prognosis and post-COVID lung sequelae in hospitalized patients with COVID-19.

METHODS

Serum levels of the three adipokines were measured upon admission of polymerase chain reaction-confirmed patients with COVID-19 who were followed up for 6 months for the clinical outcome and lung sequelae formation.

RESULTS

A total of 77 patients were included in the study. Of the 77 patients, 58.4% were males, and the median age was 63.2 ± 18.3 years. Fifty-one patients (66.2%) had a good prognosis. Among adipokines, only chemerin was significantly lower in the bad prognosis group (P < 0.05), and the serum levels showed a negative correlation with age (rho = -0.238; P < 0.05). Leptin levels were negatively correlated with gamma glutamyl transferase levels, which were significantly higher in the bad prognostic group (rho = -0.240; P < 0.05). Twenty-four patients had no lung sequelae, and 20 developed sequelae within 6 months after infection. Chemerin/adiponectin ratio with a cut-off value of 0.96 and an area under the curve 0.679 (P < 0.05) might predict the sequelae formation.

CONCLUSIONS

Chemerin levels are lower, especially in patients with a bad prognosis, and the chemerin/adiponectin ratio might predict the development of lung sequelae in patients with COVID-19.

Association between abdominal and general obesity and respiratory symptoms, asthma and COPD. Results from the RHINE study

INTRODUCTION

Previous studies on the association between abdominal and general obesity and respiratory disease have provided conflicting results.

AIMS AND OBJECTIVES

We aimed to explore the associations of abdominal obesity with respiratory symptoms, asthma, and chronic obstructive pulmonary disease independently from general obesity in women and men.

METHODS

This cross-sectional study was based on the Respiratory Health in Northern Europe (RHINE) III questionnaire (n = 12 290) conducted in 2010-2012. Abdominal obesity was self-measured waist circumference using a sex-specific standard cut-off point: ≥102 cm in males and ≥88 cm in females. General obesity was defined as self-reported BMI ≥30.0 kg/m².

RESULTS

There were 4261 subjects (63% women) with abdominal obesity and 1837 subjects (50% women) with general obesity. Both abdominal and general obesity was independent of each other and associated with respiratory symptoms (odds ratio (OR) from 1.25 to 2.00)). Asthma was significantly associated with abdominal and general obesity in women, OR (95% CI) 1.56 (1.30-1.87) and 1.95 (1.56-2.43), respectively, but not in men, OR 1.22 (0.97-3.17) and 1.28 (0.97-1.68) respectively. A similar sex difference was found for self-reported chronic obstructive pulmonary disease.

CONCLUSIONS

General and abdominal obesity were independent factors associated with respiratory symptoms in adults. Asthma and chronic obstructive pulmonary disease were independently linked to abdominal and general obesity in women but not men.

An Increase in Plasma Adipsin Levels Is Associated With Higher Cumulative Dust Exposure and Airway Obstruction in Foundry Workers

OBJECTIVE

The aim of the study was to assess whether plasma adipokine levels (adipsin, adiponectin, leptin, and resistin) are associated with pulmonary function in foundry workers.

METHODS

We examined 65 dust-exposed foundry workers and 40 nonexposed controls and analyzed their lung function and plasma adipokine levels at baseline and after approximately 7 years of follow-up.

RESULTS

A higher increase in plasma adipsin was associated with the development of airway obstruction in exposed subjects during follow-up after adjusting for body mass index changes during the follow-up period. Furthermore, the increase in adipsin levels was positively associated with cumulative dust exposure even after adjusting for smoking and body mass index changes during follow-up ( P = 0.015).

CONCLUSION

The results suggest that plasma adipsin is involved in the pathogenesis of subclinical airway inflammation and the development of chronic obstruction and is induced by occupational dust exposure.

Leptin and Asthma: What Are the Interactive Correlations?

Leptin is an adipokine directly correlated with the proinflammatory obese-associated phenotype. Leptin has been demonstrated to inhibit adipogenesis, promote fat demarcation, promote a chronic inflammatory state, increase insulin sensitivity, and promote angiogenesis. Leptin, a regulator of the immune response, is implicated in the pathology of asthma. Studies involved in the key cell reaction and animal models of asthma have provided vital insights into the proinflammatory role of leptin in asthma. Many studies described the immune cell and related cellular pathways activated by leptin, which are beneficial in asthma development and increasing exacerbations. Subsequent studies relating to animal models support the role of leptin in increasing inflammatory cell infiltration, airway hyperresponsiveness, and inflammatory responses. However, the conclusive effects of leptin in asthma are not well elaborated. In the present study, we explored the general functions and the clinical cohort study supporting the association between leptin and asthma. The main objective of our review is to address the knowns and unknowns of leptin on asthma. In this perspective, the arguments about the different faces of leptin in asthma are provided to picture the potential directions, thus yielding a better understanding of asthma development.

Trends in asthma among adults in the United States, National Health and Nutrition Examination Survey 2005 to 2018

BACKGROUND

Asthma is a common chronic disease in American adults. The prevalence of asthma has varied over time, but there are few studies on the long-term trend of asthma in American adults.

OBJECTIVE

To describe the prevalence and trend of asthma in American adults from 2005 to 2018 and analyze the risk factors for asthma.

METHODS

Data collection was performed from National Health and Nutrition Examination Survey 2005 to 2018. The unweighted number and weighted percentages of normal participants and patients with asthma and the trends of asthma were calculated. Weighted univariate logistic regression was used to analyze the risk factors for asthma.

RESULTS

A total of 39,601 adults were included in this study. From 2005 to 2018, the overall prevalence of asthma in American adults was 8.41%, whereas that in young, middle-aged, and elderly adults was 8.30%, 8.70%, and 7.92%, respectively. The estimated prevalence of asthma in the overall adults and young adults increased with time (P for trend = .03, difference = 0.023 and P for trend = .007, difference = 0.060, respectively), and the estimated prevalence of middle-aged and elderly adults remained stable with time (P for trend = .33, difference = 0.015 and P for trend = .80, difference = -0.024, respectively).

CONCLUSION

Asthma in American adults was on the rise. Female sex, non-Hispanic Blacks, individuals with low annual household income, active smokers, obese patients, patients with hypertension, patients with diabetes, and individuals with positive asthma family history were associated with a higher risk for developing asthma.

Circulating CTRP5 in rheumatoid arthritis: an exploratory biomarker study

Background

Rheumatoid arthritis (RA) is an inflammatory disease that is characterized by the overproduction of cytokines. Among the newly discovered cytokines are the adipokines which are primarily produced by and released from the adipose tissue and some immune cells, as well as synovial cells. they are involved in various immune responses and inflammatory processes. However, there are controversial data regarding the pro-inflammatory or anti-inflammatory effects of adipokines in different conditions. C1q/TNF-related protein 5 (CTRP5) is a newly identified adipokine and adiponectin paralogous protein, which has been shown to be correlated with inflammatory diseases. Accordingly, the present study was designed to investigate the serum levels of CTRP5 in RA patients and evaluate any possible alterations in comparison to healthy individuals.

Methods

Serum CTRP-5 levels were measured in 46 patients and 22 healthy controls by ELISA. The demographic, laboratory, and clinical features of the patients were also evaluated in order to find any correlations.

Results

Serum levels of CTRP-5 were significantly (p < 0.0001) higher in patients with RA (14.88 ± 25.55) compared to healthy controls (4.262 ± 2.374). There was a significant correlation between serum CTRP-5 levels and triglyceride (TG) (r: − 0.3010, p: 0.0498), as well as erythrocyte sedimentation rate (ESR) (r: 0.3139, p: 0.0457), C-reactive protein (CRP) (r: 0.5140, p: 0.0008), and the number of white blood cells (WBC) (r: 0.3380, p: 0.0307), which are considered as the markers indicating the extent of inflammation. Moreover, CTRP-5 was found to be correlated with interstitial lung disease (ILD) (r: 0.3416, p: 0.0385), a comorbidity associated with RA disease.

Conclusion

This study demonstrated the increased level of circulating CTRP-5 in RA patients, which correlated with some inflammation-associated parameters and RA-associated comorbidities. Our observations suggest CTRP-5 as a putative inflammatory biomarker in RA, which may be useful besides the other disease-related markers.

Adiponectin Inhibits the Production of TNF-α, IL-6 and Chemokines by Human Lung Macrophages

Background: Obesity is associated with an elevated risk of severe respiratory infections and inflammatory lung diseases. The objectives were to investigate 1) the production of adiponectin by human lung explants, 2) the expression of the adiponectin receptors AdipoR1 and AdipoR2 by human lung macrophages (LMs), and 3) the impact of recombinant human adiponectin and a small-molecule APN receptor agonist (AdipoRon) on LMs activation. Material and methods: Human parenchyma explants and LMs were isolated from patients operated for carcinoma. The LMs were cultured with recombinant adiponectin or AdipoRon and stimulated with lipopolysaccharide (10 ng ml^-1), poly (I:C) (10 µg ml^-1) or interleukin (IL)-4 (10 ng ml^-1) for 24 h. Cytokines or adiponectin, released by explants or LMs, were measured using ELISAs. The mRNA levels of AdipoR1 and AdipoR2 were determined using real-time quantitative PCR. AdipoRs expression was also assessed with confocal microscopy. Results: Adiponectin was released by lung explants at a level negatively correlated with the donor's body mass index. AdipoR1 and AdipoR2 were both expressed in LMs. Adiponectin (3-30 µg ml^-1) and AdipoRon (25-50 μM) markedly inhibited the LPS- and poly (I:C)-induced release of Tumor Necrosis Factor-α, IL-6 and chemokines (CCL3, CCL4, CCL5, CXCL1, CXCL8, CXCL10) and the IL-4-induced release of chemokines (CCL13, CCL17, CCL22) in a concentration-dependent manner. Recombinant adiponectin produced in mammalian cells (lacking low molecular weight isoforms) had no effects on LMs. Conclusion and implications: The low-molecular-weight isoforms of adiponectin and AdipoRon have an anti-inflammatory activity in the lung environment. Targeting adiponectin receptors may constitute a new means of controlling airways inflammation.

Association of obesity-related inflammatory pathways with lung function and exercise capacity

BACKGROUND

Obesity has multifactorial effects on lung function and exercise capacity. The contributions of obesity-related inflammatory pathways to alterations in lung function remain unclear.

RESEARCH QUESTION

To examine the association of obesity-related inflammatory pathways with pulmonary function, exercise capacity, and pulmonary-specific contributors to exercise intolerance.

METHOD

We examined 695 patients who underwent cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring at Massachusetts General Hospital between December 2006-June 2017. We investigated the association of adiponectin, leptin, resistin, IL-6, CRP, and insulin resistance (HOMA-IR) with pulmonary function and exercise parameters using multivariable linear regression.

RESULTS

Obesity-related inflammatory pathways were associated with worse lung function. Specifically, higher CRP, IL-6, and HOMA-IR were associated with lower percent predicted FEV₁ and FVC with a preserved FEV₁/FVC ratio suggesting a restrictive physiology pattern (P ≤ 0.001 for all). For example, a 1-SD higher natural-logged CRP level was associated with a nearly 5% lower percent predicted FEV₁ and FVC (beta -4.8, s.e. 0.9 for FEV1; beta -4.9, s.e. 0.8 for FVC; P < 0.0001 for both). Obesity-related inflammatory pathways were associated with worse pulmonary vascular distensibility (adiponectin, IL-6, and CRP, P < 0.05 for all), as well as lower pulmonary artery compliance (IL-6 and CRP, P ≤ 0.01 for both).

INTERPRETATION

Our findings highlight the importance of obesity-related inflammatory pathways including inflammation and insulin resistance on pulmonary spirometry and pulmonary vascular function. Specifically, systemic inflammation as ascertained by CRP, IL-6 and insulin resistance are associated with restrictive pulmonary physiology independent of BMI. In addition, inflammatory markers were associated with lower exercise capacity and pulmonary vascular dysfunction.

Impact of obesity on pulmonary function: current understanding and knowledge gaps

PURPOSE OF REVIEW

Obesity is an increasing world-wide public health concern. Obesity both causes respiratory symptoms and contributes to many cardiorespiratory diseases. The effects of obesity on commonly used lung function tests are reviewed.

RECENT FINDINGS

The effects of obesity on lung function are attributed both to mechanical factors and to complex metabolic effects that contribute to a pro-inflammatory state. The effects of obesity on lung function correlate with BMI and correlate even better when the distribution of excess adipose tissue is taken into account, with central obesity associated with more prominent abnormalities. Obesity is associated with marked decreases in expiratory reserve volume and functional residual capacity. Total lung capacity, residual volume, and spirometry are less affected by obesity and are generally within the normal range except with severe obesity. Obesity decreases total respiratory system compliance primarily because of decreased lung compliance, with only mild effects on chest wall compliance. Obesity is associated with impaired gas transfer with decreases in oxygenation and varied but usually mild effects on diffusing capacity for carbon monoxide, while the carbon monoxide transfer coefficient is often increased.

SUMMARY

Obesity has significant effects on lung function. The relative contribution of the mechanical effects of obesity and the production of inflammatory cytokines by adipose tissue on lung function needs further study.

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

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

Obesity is a risk factor for exercise-induced bronchospasm in asthmatic adolescents

INTRODUCTION

Exercise-induced bronchospasm (EIB) is common in young asthmatics and obesity is becoming an epidemic in this population. Both conditions can give rise to or worsen respiratory symptoms upon exercise and may interfere with recreational and sports activities.

OBJECTIVE

To investigate the association between obesity and the risk and severity of EIB in asthmatic children and adolescents.

METHODS

This study included data from asthmatic patients aged between 7 and 19 years undergoing treadmill running tests to evaluate EIB, defined as a reduction greater than or equal to 10% in forced expiratory volume in the first second (FEV₁ ) compared to baseline. Eutrophic, obese, and overweight individuals were categorized according to body mass index z-score (eutrophic, -0.5 < z ≤ 1; overweight, 1 < z < 2; and obese, z ≥ 2).

RESULTS

Of the 156 individuals studied (42% female), 58% were eutrophic, 22% overweight, and 19% obese. Seventy-three individuals (47%) presented with EIB, with higher risk among obese (OR, 2.86; 95% CI, 1.00-8.14; P = .05). Asthma severity was another independent risk factor for EIB (OR, 2.95; 95% CI, 1.36-6.42; P = .006). The number of patients in whom FEV₁ returned to baseline values (difference less than 10% from baseline) at the 13th minute after challenge was lower in obese individuals compared to eutrophic and overweight ones (P = .04). Baseline FEV₁ , gender, or age were not found to be risk factors for EIB in any of the groups.

CONCLUSION

Obese youngsters with asthma present a greater risk for EIB with slower recovery than their nonobese peers. Clinicians should be aware of this association, especially in those with more severe disease, for adequate recognition and treatment.

Somatotypes trajectories during adulthood and their association with COPD phenotypes

RATIONALE

Chronic obstructive pulmonary disease (COPD) comprises distinct phenotypes, all characterised by airflow limitation.

OBJECTIVES

We hypothesised that somatotype changes - as a surrogate of adiposity - from early adulthood follow different trajectories to reach distinct phenotypes.

METHODS

Using the validated Stunkard's Pictogram, 356 COPD patients chose the somatotype that best reflects their current body build and those at ages 18, 30, 40 and 50 years. An unbiased group-based trajectory modelling was used to determine somatotype trajectories. We then compared the current COPD-related clinical and phenotypic characteristics of subjects belonging to each trajectory.

MEASUREMENTS AND MAIN RESULTS

At 18 years of age, 88% of the participants described having a lean or medium somatotype (estimated body mass index (BMI) between 19 and 23 kg·m-2) while the other 12% a heavier somatotype (estimated BMI between 25 and 27 kg·m-2). From age 18 onwards, five distinct trajectories were observed. Four of them demonstrating a continuous increase in adiposity throughout adulthood with the exception of one, where the initial increase was followed by loss of adiposity after age 40. Patients with this trajectory were primarily females with low BMI and D LCO (diffusing capacity of the lung for carbon monoxide). A persistently lean trajectory was seen in 14% of the cohort. This group had significantly lower forced expiratory volume in 1 s (FEV1), D LCO, more emphysema and a worse BODE (BMI, airflow obstruction, dyspnoea and exercise capacity) score thus resembling the multiple organ loss of tissue (MOLT) phenotype.

CONCLUSIONS

COPD patients have distinct somatotype trajectories throughout adulthood. Those with the MOLT phenotype maintain a lean trajectory throughout life. Smoking subjects with this lean phenotype in early adulthood deserve particular attention as they seem to develop more severe COPD.

Contentious role of 'Good Adiponectin' in pulmonary and cardiovascular diseases: Is adiponectin directed therapy a boon or a bane?

After two decades of its discovery, numerous facts of adiponectin (APN) biology has been uncovered, yet, APN remains an elusive adipokine. Findings from clinical studies and animal models established APN's ameliorative role in cardiovascular disease (CVD) and pulmonary disease (PD) but the same condition is prognostic for mortality in the same set of patients which cornered APN towards a dubious state. A repertoire of mechanisms associated with the positive association of APN in both lean/cachectic or obese CVD and PD patients from past publications are evaluated. Newer pharmacological agent may be explored to regulate elevated blood APN concentration in COPD or CHF patients whereas administration of recombinant APN as well as growth hormone may augment blood APN concentration in obese subjects associated with low blood and intracellular APN concentration. However, some APN directed therapy in clinical as well as in pre-clinical setup has pronounced some contentious effects. After reviewing the mechanisms of the contentious role of APN functioning in pathologic conditions of CVD and PD in both lean and obese conditions, the authors came to conclusion that APN directed therapy may be utilized with caution keeping in mind the different age group, sex and the different CVD as well as pulmonary diseases they are suffering from.

Characterising a Weight Loss Intervention in Obese Asthmatic Children

The prevalence of obesity in asthmatic children is high and is associated with worse clinical outcomes. We have previously reported that weight loss leads to improvements in lung function and asthma control in obese asthmatic children. The objectives of this secondary analysis were to examine: (1) changes in diet quality and (2) associations between the baseline subject characteristics and the degree of weight loss following the intervention. Twenty-eight obese asthmatic children, aged 8–17 years, completed a 10-week diet-induced weight loss intervention. Dietary intake, nutritional biomarkers, anthropometry, lung function, asthma control, and clinical outcomes were analysed before and after the intervention. Following the intervention, the body mass index (BMI) z-score decreased (Δ = 0.18 ± 0.04; p < 0.001), %energy from protein increased (Δ = 4.3 ± 0.9%; p = 0.002), and sugar intake decreased (Δ = 23.2 ± 9.3 g; p= 0.025). Baseline lung function and physical activity level were inversely associated with Δ% fat mass. The ΔBMI z-score was negatively associated with physical activity duration at baseline. Dietary intervention is effective in achieving acute weight loss in obese asthmatic children, with significant improvements in diet quality and body composition. Lower lung function and physical engagement at baseline were associated with lesser weight loss, highlighting that subjects with these attributes may require greater support to achieve weight loss goals.

Obesity, but not metabolic syndrome, as a risk factor for late-onset asthma in Japanese women

BACKGROUND

Several cross-sectional studies have suggested an association between obesity and asthma. However, few studies have investigated this relationship longitudinally, especially in middle-aged subjects. Although metabolic syndrome is a well-known risk factor for many non-communicable diseases, its contribution to asthma remains controversial.

METHODS

From 2008, specific health checkups for metabolic syndrome have been conducted throughout Japan. To seek relationships of obesity and metabolic syndrome with late-onset asthma in Japan, we analyzed data collected from health insurance claims and specific health checkups for metabolic syndrome at three large health insurance societies. Among subjects aged 40-64 years (n = 9888), multivariate logistic regression analyses were performed to investigate the relationships of obesity and metabolic syndrome in fiscal year 2012 (from April 2012 to March 2013) with the incidence of late-onset asthma in the following two years (from April 2013 to March 2015).

RESULTS

In women, BMI 25-29.9 kg/m² or ≥30 kg/m², waist circumference ≥90 cm, and waist-to-height ratio ≥0.5 were shown to be significant risk factors for asthma, with adjusted odds ratios (95% CI) of 1.92 (1.35-2.75), 2.24 (1.23-4.09), 1.89 (1.30-2.75), and 1.53 (1.15-2.03), respectively. Significance was retained even after adjustment for metabolic syndrome, and there were no significant relationships between metabolic syndrome itself and the incidence of asthma in men or women.

CONCLUSIONS

Only the obesity measures, not metabolic syndrome, were shown to be significant risk factors for the incidence of late-onset asthma but only in middle-aged Japanese women, and not in men.

Imaging-based clusters in current smokers of the COPD cohort associate with clinical characteristics: the SubPopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

BACKGROUND

Classification of COPD is usually based on the severity of airflow, which may not sensitively differentiate subpopulations. Using a multiscale imaging-based cluster analysis (MICA), we aim to identify subpopulations for current smokers with COPD.

METHODS

Among the SPIROMICS subjects, we analyzed computed tomography images at total lung capacity (TLC) and residual volume (RV) of 284 current smokers. Functional variables were derived from registration of TLC and RV images, e.g. functional small airways disease (fSAD%). Structural variables were assessed at TLC images, e.g. emphysema and airway wall thickness and diameter. We employed an unsupervised method for clustering.

RESULTS

Four clusters were identified. Cluster 1 had relatively normal airway structures; Cluster 2 had an increase of fSAD% and wall thickness; Cluster 3 exhibited a further increase of fSAD% but a decrease of wall thickness and airway diameter; Cluster 4 had a significant increase of fSAD% and emphysema. Clinically, Cluster 1 showed normal FEV1/FVC and low exacerbations. Cluster 4 showed relatively low FEV1/FVC and high exacerbations. While Cluster 2 and Cluster 3 showed similar exacerbations, Cluster 2 had the highest BMI among all clusters.

CONCLUSIONS

Association of imaging-based clusters with existing clinical metrics suggests the sensitivity of MICA in differentiating subpopulations.

Pulmonary vascular dysfunction in metabolic syndrome

Metabolic syndrome is a critically important precursor to the onset of many diseases, such as cardiovascular disease, and cardiovascular disease is the leading cause of death worldwide. The primary risk factors of metabolic syndrome include hyperglycaemia, abdominal obesity, dyslipidaemia, and high blood pressure. It has been well documented that metabolic syndrome alters vascular endothelial and smooth muscle cell functions in the heart, brain, kidney and peripheral vessels. However, there is less information available regarding how metabolic syndrome can affect pulmonary vascular function and ultimately increase an individual's risk of developing various pulmonary vascular diseases, such as pulmonary hypertension. Here, we review in detail how metabolic syndrome affects pulmonary vascular function.

Dual effects of leptin in perioperative gas exchange of morbidly obese patients

Leptin has shown positive effects on respiratory function in experimental settings. The role of leptin on perioperative respiratory function in morbidly obese patients has not been established. We performed a retrospective analysis of morbidly obese patients undergoing laparoscopic sleeve gastrectomy. Fasting serum leptin and interleukin (IL)-6 were measured preoperatively, and arterial blood gases were obtained pre- and postoperatively. Outcome variables were arterial partial pressure of oxygen (PaO₂), arterial partial pressure of carbon dioxide (PaCO₂), and differences in PaO₂ and PaCO₂ between pre- and postoperative values (ΔPaO₂, ΔPaCO₂; postoperative minus preoperative). Patients with lower (<40 μg/L) and higher (≥40 μg/L) leptin levels were compared. Bravais-Pearson’s correlation, multiple linear regression, and logistic regression analysis were performed. A total of 112 morbidly obese patients were included. Serum leptin was significantly higher in females than in males (42.86±12.89 vs. 30.67±13.39 μg/L, p<0.0001). Leptin was positively correlated with body mass index (r = 0.238; p = 0.011), IL-6 (r = 0.473; p<0.0001), and ΔPaO₂ (r = 0.312; p = 0.0008). Leptin was negatively correlated with preoperative PaO₂ (r = -0.199; p = 0.035). Preoperative PaO₂ was lower, ΔPaCO₂ was smaller, and ΔPaO₂ was greater in the high leptin group than in the low leptin group. In multiple regression analysis, leptin was negatively associated with preoperative PaO₂ (estimate coefficient = -0.147; p = 0.023). In logistic regression analysis, leptin was associated with improved ΔPaO₂ (odds ratio [OR] = 1.104; p = 0.0138) and ΔPaCO₂ (OR = 0.968; p = 0.0334). Leptin appears to have dual effects related to perioperative gas exchange in obese patients undergoing bariatric surgery. It is associated with worse preoperative oxygenation but improved respiratory function after surgery.

Leptin/Osteopontin Axis Regulated Type 2T Helper Cell Response in Allergic Rhinitis with Obesity

The prevalence of allergic rhinitis (AR) and obesity in children increased concurrently during recent decades. However, the molecular pathway involved in the interaction between obesity and AR is still unclear. We aimed to investigate the interaction between leptin and osteopontin (OPN) and their effect on T helper (T_H) response in the development of AR in children. Thirty AR and 30 healthy children with or without obesity were enrolled. Serum leptin and OPN levels were measured and their relationship with T_H1/2 cytokines was analyzed. T_H cell differentiation and cytokine production in peripheral blood mononuclear cells (PBMCs) stimulated by leptin and/or OPN were analyzed by enzyme linked immunosorbent assay (ELISA). Obese AR mice models were established to verify the effect of obesity on leptin and OPN as well T_H regulation. Immunoprecipitation was performed to confirm the interaction between OPN and leptin in CD4+ T cells. Our results showed elevated serum leptin and OPN in AR children correlated with T_H2 cytokines expression. Leptin and OPN enhanced T_H2 inflammation in house dust mite stimulated PBMCs from AR children synergistically. Obese AR mice showed as more severe inflammatory reaction, symptoms and expression of nasal leptin and OPN compared with other groups. Immunoprecipitation suggested that OPN and leptin may interact with each other and this process may be mediated by α4 integrin and PI3K/AKT pathway in CD4+ T cells. Our data provide evidence that leptin-mediated OPN upregulation promote T_H2 inflammation in AR and this process is achieved through the α4 integrin and PI3K/AKT signaling pathways.

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Previous studies suggested that both leptin and osteopontin are increased in allergic rhinitis patients and related to the severity of disease. We also provide evidence that leptin and osteopontin contributes to T_H2-skewed airway diseases. In the present study, our data suggested that obesity and allergic rhinitis interacted closely through leptin and OPN, and these cytokines may be used as potential biomarkers for disease severity of allergic rhinitis despite that more studies were needed.

Obese asthmatics are characterized by altered adipose tissue macrophage activation

BACKGROUND

Adipose tissue-derived inflammation is linked to obesity-related comorbidities. This study aimed to quantify and immuno-phenotype adipose tissue macrophages (ATMs) from obese asthmatics and obese non-asthmatics and to examine associations between adipose tissue, systemic and airway inflammation.

METHODS

Visceral (VAT) adipose tissue and subcutaneous (SAT) adipose tissue were collected from obese adults undergoing bariatric surgery and processed to obtain the stromovascular fraction. Pro-inflammatory (M1) and anti-inflammatory (M2) macrophages were quantified by flow cytometry. Cytospins of induced sputum were stained for differential cell counts. Plasma C-reactive protein (CRP) and CD163 were measured by ELISA.

RESULTS

VAT contained a higher number of ATMs compared to SAT. A higher percentage of M1 ATMs was observed in VAT of obese asthmatics compared to obese non-asthmatics. The M1:M2 ratio in VAT was negatively associated with FEV₁ %. Sputum macrophage count was correlated positively with M1 ATMs and negatively with M2 ATMs in VAT. In obese asthmatics, CRP was positively associated with M1:M2 ratio in VAT. There were no associations with CD163. An elevated ratio of M1:M2 ATMs was observed in VAT of obese asthmatics with increased disease severity.

CONCLUSIONS AND CLINICAL RELEVANCE

Visceral inflammation with increased pro-inflammatory macrophages (M1) occurs in obese asthma and may be a determinant of systemic inflammation and asthma severity.

What do polymorphisms tell us about the mechanisms of COPD?

COPD (chronic obstructive pulmonary disease) is characterized by irreversible lung airflow obstruction. Cigarette smoke is the major risk factor for COPD development. However, only a minority number of smokers develop COPD, and there are substantial variations in lung function among smokers, suggesting that genetic determinants in COPD susceptibility. During the past decade, genome-wide association studies and exome sequencing have been instrumental to identify the genetic determinants of complex traits, including COPD. Focused studies have revealed mechanisms by which genetic variants contribute to COPD and have led to novel insights in COPD pathogenesis. Through functional investigations of causal variants in COPD, from the proteinase-antiproteinase theory to emerging roles of developmental pathways (such as Hedgehog and Wnt pathways) in COPD, we have greatly expanded our understanding on this complex pulmonary disease. In this review, we critically review functional investigations on roles of genetic polymorphisms in COPD, and discuss future challenges and opportunities in discovering novel mechanisms of functional variants.

Rapid decline in lung function is temporally associated with greater metabolically active adiposity in a longitudinal study of healthy adults

RATIONALE

Adiposity is associated with low lung function, but the longitudinal relationship between lung function and adiposity is inadequately studied.

OBJECTIVE

To examine the bidirectional longitudinal associations between rapid decline in lung function and adiposity phenotypes in healthy adults.

METHODS

This secondary analysis used a 25-year longitudinal dataset from the Coronary Artery Risk Development in Young Adults (CARDIA) study that enrolled 5115 participants.

MEASUREMENTS

In the first analysis, metabolic syndrome at or before CARDIA year (Y) 10 (Y10) was the predictor, and subsequent rapid decline in forced vital capacity (FVC) or forced expiratory volume in 1 s (FEV1) between Y10 and Y20 was the outcome. In the second analysis, rapid decline was the predictor, and incident metabolic syndrome at Y20 and/or Y25 was the outcome. In the third analysis, rapid decline was the predictor, and subsequent CT-assessed regional fat depots at Y25 were the outcome.

RESULTS

Metabolic syndrome at or before Y10 is temporally associated with rapid decline in FVC between Y10 and Y20 (adjusted p=0.04), but this association was explained by body mass index (BMI) at Y10. Rapid decline in FVC or FEV1 is temporally associated with greater incident metabolic syndrome at Y20 and/or Y25 (adjusted OR 2.10 (1.69, 2.61); p<0.001, and 1.56 (1.26, 1.94); p<0.001, respectively) and greater CT-assessed intrathoracic visceral adiposity at Y25 (adjusted standardised β 0.09; p<0.001 for both analyses). These associations were not explained by BMI levels prior to the outcome measurement.

CONCLUSIONS

Healthy adults with rapid decline in lung function are at risk for developing metabolic syndrome and for disproportionate accumulation of intrathoracic visceral fat. Metabolic abnormalities may be an early extrapulmonary manifestation of lung impairment that may be preventable by improving lung health.

Innate lymphoid cells at the interface between obesity and asthma

Obesity and asthma prevalence has dramatically and concomitantly increased over the last 25 years, and many epidemiological studies have highlighted obesity as an important risk factor for asthma. Although many studies have been performed, the underlying mechanisms remain poorly understood. Innate mechanisms have been involved in both diseases, in particular through the recently described innate lymphoid cells (ILCs). ILCs are subdivided into three groups that are defined by their cytokine production and by their master transcription factor expression, in sharp correlation with their T helper counterparts. However, unlike T helper cells, ILCs do not express antigen-specific receptors, but respond to damage-induced signals. ILCs have been found in target tissues of both diseases, and data have implicated these cells in the pathogenesis of both diseases. In particular group 2 ILCs (ILC2) are activated in both the adipose and lung tissues under the effect of interleukin-33 and interleukin-25 expression. However, counter-intuitively to the well-known association between obesity and asthma, ILC2 are beneficial for obesity but deleterious for asthma. This review will examine the roles of ILCs in each disease and recent data highlighting ILCs as a putative link between obesity and asthma.

Impact of overweight and obesity on acute exacerbations of COPD - subgroup analysis of the Taiwan Obstructive Lung Disease cohort

Purpose

A low body mass index (BMI) is a poor prognostic marker of acute exacerbations and mortality in patients with COPD. However, the impact of overweight and obesity on COPD-related outcomes is uncertain. The aim of this study was to examine whether a high BMI is associated with the frequent exacerbator phenotype (≥2/year) in Taiwanese patients with COPD.

Patients and methods

Data were obtained from the Taiwan Obstructive Lung Disease study, a retrospective, observational nationwide survey of COPD patients conducted at 12 hospitals in Taiwan. Multivariate logistic regression models were used to explore the association between BMI and other factors with the frequency of COPD exacerbations in these patients.

Results

Among the whole study cohort (n=1,096), 735 (67.1%) had no exacerbations and 148 (13.5%) were frequent exacerbators in the previous year. The BMI values of the patients with 0, 1, and ≥2 exacerbations were 23.6, 23.5, and 22.6 kg/m², respectively. In all, 256 (23.4%) and 196 (17.9%) patients were overweight (27 kg/m² > BMI ≥24 kg/m²) and obese (BMI ≥27 kg/m²), respectively. Even after adjusting for multiple factors, overweight and obesity were associated with the frequency of exacerbations (odds ratio [95% confidence interval] 0.49 [0.28–0.87, P=0.015] and 0.49 [0.26–0.94, P=0.033], respectively).

Conclusion

Our results suggest that overweight and obesity are associated with a lower frequency of COPD exacerbations in Taiwan.

Ozone Exposure, Cardiopulmonary Health, and Obesity: A Substantive Review

From 1999-2014, obesity prevalence increased among adults and youth. Obese individuals may be uniquely susceptible to the proinflammatory effects of ozone because obese humans and animals have been shown to experience a greater decline in lung function than normal-weight subjects. Obesity is independently associated with limitations in lung mechanics with increased ozone dose. However, few epidemiologic studies have examined the interaction between excess weight and ozone exposure among adults. Using PubMed keyword searches and reference lists, we reviewed epidemiologic evidence to identify potential response-modifying factors and determine if obese or overweight adults are at increased risk of ozone-related health effects. We initially identified 170 studies, of which seven studies met the criteria of examining the interaction of excess weight and ozone exposure on cardiopulmonary outcomes in adults, including four short-term ozone exposure studies in controlled laboratory settings and three community epidemiologic studies. In the studies identified, obesity was associated with decreased lung function and increased inflammatory mediators. Results were inconclusive about the effect modification when data were stratified by sex. Obese and overweight populations should be considered as candidate at-risk groups for epidemiologic studies of cardiopulmonary health related to air pollution exposures. Air pollution is a modifiable risk factor that may decrease lung function among obese individuals with implications for environmental and occupational health policy.

Risk Factors for Chronic Cough Among 14,669 Individuals From the General Population

BACKGROUND

Risk factors for chronic cough in the general population have not been described systematically. We identified and ranked chronic cough risk factors at the individual and community level using data from 14,669 individuals from the Copenhagen General Population Study.

METHODS

Severity of chronic cough was assessed using the Leicester Cough Questionnaire (LCQ). We ranked chronic cough risk factors based on magnitude of age-adjusted ORs at the individual level and of the population attributable risks (PARs) at the community level.

RESULTS

Prevalence of chronic cough in the general population was 4% overall and 3% in never smokers, 4% in former smokers, and 8% in current smokers. Median score of the LCQ was 5.8 (25th-75th percentile, 5.0-6.3) for physical domain, 5.6 (25th-75th percentile, 4.6-6.3) for psychologic domain, 6.3 (25th-75th percentile, 5.5-6.8) for social domain, and 17.3 (25th- 75th percentile, 15.4-18.9) in total. At the level of the individual, age-adjusted ORs for the three top-ranked risk factors were 5.0 (95% CI, 1.4-18) for bronchiectasis, 2.6 (95% CI, 1.7-3.9) for asthma and 2.3 (95% CI, 1.5-3.4) for gastroesophageal reflux disease in never smokers, 7.1 (95% CI, 2.6-20) for bronchiectasis, 3.1 (95% CI, 2.2-4.4) for asthma and 2.2 (95% CI, 1.5-3.2) for occupational exposure to dust/fumes in former smokers, and 1.9 (95% CI, 1.3-2.9) for airflow limitation in current smokers. At the level of the community, the three top-ranked risk factors were female sex (PAR, 19%), asthma (PAR, 10%), and gastroesophageal reflux disease (PAR, 8%) in never smokers; abdominal obesity (PAR, 20%), low income (PAR, 20%), and asthma (PAR, 13%) in former smokers; and airflow limitation (PAR, 23%) in current smokers.

CONCLUSIONS

Risk factors for chronic cough differ at the level of the individual and community, and by smoking status. Strategies to prevent and treat modifiable chronic cough risk factors should be tailored accordingly.

Obesity Is Associated With Increased Morbidity in Moderate to Severe COPD

BACKGROUND

Obesity is prevalent in the United States; however, the impact of obesity on COPD morbidity is unclear. We hypothesized that obesity is associated with worse outcomes in COPD.

METHODS

We examined 3,631 participants from the multicenter prospective cohort study Genetic Epidemiology of COPD (COPDGene) who had spirometry-confirmed COPD, a postbronchodilator FEV₁ < 80% predicted, and a BMI ≥ 18.5 kg/m². We conducted logistic and linear regression analyses to determine the association between COPD outcomes and obesity class, adjusting for relevant confounders. The referent for obesity classes included normal/overweight individuals (BMI range, 18.5-29.9 kg/m²).

RESULTS

Overall, 35% of participants were obese, with 21% class I (BMI range, 30-34.9 kg/m²), 9% class II (BMI range, 35-39.9 kg/m²), and 5% class III (BMI ≥ 40 kg/m²). The number of comorbidities increased with increasing obesity class (P < .001). Increasing obesity class was independently associated with worse respiratory-specific and general quality of life (QOL) (St. George's Respiratory Questionnaire score and Short Form-36 score version 2, respectively), reduced 6-min walk distance (6MWD), increased dyspnea (Modified Medical Research Council score ≥ 2), and greater odds of severe acute exacerbation of COPD (AECOPD). The associations between obesity and worse outcomes were independent of the presence of comorbidities, except in the case of SF-36 and severe exacerbations.

CONCLUSIONS

Obesity is prevalent among individuals with COPD and associated with worse COPD-related outcomes, ranging from QOL and dyspnea to 6MWD and severe AECOPD. These associations were strengthened when obesity was analyzed as a dose-dependent response. Obesity in patients with COPD may contribute to a worse COPD-related course.

Adiposity influences airway wall thickness and the asthma phenotype of HIV-associated obstructive lung disease: a cross-sectional study

Background

Airflow obstruction, which encompasses several phenotypes, is common among HIV-infected individuals. Obesity and adipose-related inflammation are associated with both COPD (fixed airflow obstruction) and asthma (reversible airflow obstruction) in HIV-uninfected persons, but the relationship to airway inflammation and airflow obstruction in HIV-infected persons is unknown. The objective of this study was to determine if adiposity and adipose-associated inflammation are associated with airway obstruction phenotypes in HIV-infected persons.

Methods

We performed a cross-sectional analysis of 121 HIV-infected individuals assessed with pulmonary function testing, chest CT scans for measures of airway wall thickness (wall area percent [WA%]) and adipose tissue volumes (mediastinal and subcutaneous), as well as HIV- and adipose-related inflammatory markers. Participants were defined as COPD phenotype (post-bronchodilator FEV₁/FVC < lower limit of normal) or asthma phenotype (doctor-diagnosed asthma or bronchodilator response). Pearson correlation coefficients were calculated between adipose measurements, WA%, and pulmonary function. Multivariable logistic and linear regression models were used to determine associations of airflow obstruction and airway remodeling (WA%) with adipose measurements and participant characteristics.

Results

Twenty-three (19 %) participants were classified as the COPD phenotype and 33 (27 %) were classified as the asthma phenotype. Body mass index (BMI) was similar between those with and without COPD, but higher in those with asthma compared to those without (mean [SD] 30.7 kg/m² [8.1] vs. 26.5 kg/m² [5.3], p = 0.008). WA% correlated with greater BMI (r = 0.55, p < 0.001) and volume of adipose tissue (subcutaneous, r = 0.40; p < 0.001; mediastinal, r = 0.25; p = 0.005). Multivariable regression found the COPD phenotype associated with greater age and pack-years smoking; the asthma phenotype with younger age, female gender, smoking history, and lower adiponectin levels; and greater WA% with greater BMI, younger age, higher soluble CD163, and higher CD4 counts.

Conclusions

Adiposity and adipose-related inflammation are associated with an asthma phenotype, but not a COPD phenotype, of obstructive lung disease in HIV-infected persons. Airway wall thickness is associated with adiposity and inflammation. Adipose-related inflammation may play a role in HIV-associated asthma.

Patient stratification and the unmet need in asthma

Asthma is often described as an inflammatory disease of the lungs and in most patients symptomatic treatment with bronchodilators or inhaled corticosteroids is sufficient to control disease. Unfortunately there are a proportion of patients who fail to achieve control despite treatment with the best current treatment. These severe asthma patients have been considered a homogeneous group of patients that represent the unmet therapeutic need in asthma. Many novel therapies have been tested in unselected asthma patients and the effects have often been disappointing, particularly for the highly specific monoclonal antibody-based drugs such as anti-IL-13 and anti-IL-5. More recently, it has become clear that asthma is a syndrome with many different disease drivers. Clinical trials of anti-IL-13 and anti-IL-5 have focused on biomarker-defined patient groups and these trials have driven the clinical progression of these drugs. Work on asthma phenotyping indicates that there is a group of asthma patients where T helper cell type 2 (Th2) cytokines and inflammation predominate and these type 2 high (T2-high) patients can be defined by biomarkers and response to therapies targeting this type of immunity, including anti-IL-5 and anti-IL-13. However, there is still a subset of T2-low patients that do not respond to these new therapies. This T2-low group will represent the new unmet medical need now that the T2-high-targeting therapies have made it to the market. This review will examine the current thinking on patient stratification in asthma and the identification of the T2-high subset. It will also look at the T2-low patients and examine what may be the drivers of disease in these patients.

Obesity and Functioning Among Individuals with Chronic Obstructive Pulmonary Disease (COPD)

In COPD, body composition studies have focused primarily on low BMI. We examined obesity (BMI ≥ 30 kg/m(2)) as a risk factor for poor function and longitudinal functional decline. Data from a longitudinal cohort of adults with COPD (n = 1096) and an age- and sex-matched comparison group collected in two in-person visits ∼49 months apart were analyzed. Two measures of functioning were examined: six-minute walk distance (6MWD) and Short Physical Performance Battery (SPPB). Multivariate regression analyses examined relationships of obesity with functioning. Secondary analyses stratified by GOLD classification (GOLD-0/1, GOLD-2, GOLD-3/4). Obesity (53% of COPD cohort) was associated cross-sectionally with 6MWD and SPPB in COPD, and only with 6MWD in the comparison group. Obesity predicted significant functional decline in 6MWD for individuals with COPD (odds ratio (OR) for decline [95% CI] 1.8 [1.1, 2.9]), but not the comparison group. Secondary analyses revealed that the risk of decline was significant only in those with more severe COPD (GOLD 3/4, OR = 2.3 [1.0, 5.4]). Obesity was highly prevalent and was associated with poor function concurrently and with subsequent decline in 6MWD in COPD. Obesity in COPD should be considered a risk not only for more co-morbidities and greater health care use, but also for functional decline.

Functional lung rejuvenation in obese patients after bariatric surgery

OBJECTIVE

To determine the lung age (LA) in obese people before and after bariatric surgery, compare the LA with the chronological age (CA) before and after the peration, and verify whether there was a functional pulmonary rejuvenation after it.

METHODS

A prospective longitudinal study including 43 morbidly obese patients who underwent bariatric surgery. The patients underwent clinical and spirometric evaluation in two stages, before and after the surgery. In both stages, LA, CA and spirometric variables were measured.

RESULTS

A significant improvement in the spirometric variables (FVC; FEV1; and FEV1/FVC ratio) was found after the operation (p≤ 0.0001). Comparing the LA before (50.93±13.36 years) and after the surgery (39.02±12.95 years), there was an important reduction of 11.90±9.12 years (95CI:9.10-14.71; p≤0.0001) in LA after surgery. The difference between LA and CA before surgery was 12.20± 11.71 years (95CI:8.60-15.81) with significant difference (p≤0.0001), and the difference between LA and CA after surgery was -1.95±11.83 years (95CI: -5.59-1.69) with no significant difference (p≤0.28). Regarding LA, we observed a pulmonary aging of 12.20±11.71 years before the surgery and a pulmonary rejuvenation of 11.90±9.12 years after it.

CONCLUSION

Morbid obesity is responsible for early damage and functional accelerated pulmonary aging. After the correction of the body weight by surgery, there is a functional pulmonary rejuvenation demonstrated by the normalization of LA in relation to CA.

MicroRNAs are associated with blood-pressure effects of exposure to particulate matter: Results from a mediated moderation analysis

AIMS

Exposure to particulate air pollution is associated with increased blood pressure (BP), a well-established risk factor for cardiovascular disease. To elucidate the mechanisms underlying this relationship, we investigated whether the effects of particulate matter of less than 10μm in aerodynamic diameter (PM10) on BP are mediated by microRNAs.

METHODS AND RESULTS

We recruited 90 obese individuals and we assessed their PM10 exposure 24 and 48h before the recruitment day. We performed multivariate linear regression models to investigate the effects of PM10 on BP. Using the TaqMan® Low-Density Array, we experimentally evaluated and technically validated the expression levels of 377 human miRNAs in peripheral blood. We developed a mediated moderation analysis to estimate the proportion of PM10 effects on BP that was mediated by miRNA expression. PM10 exposure 24 and 48h before the recruitment day was associated with increased systolic BP (β=1.22mmHg, P=0.019; β=1.24mmHg, P=0.019, respectively) and diastolic BP (β=0.67mmHg, P=0.044; β=0.91mmHg, P=0.007, respectively). We identified nine miRNAs associated with PM10 levels 48h after exposure. A conditional indirect effect (CIE=-0.1431) of PM10 on diastolic BP, which was mediated by microRNA-101, was found in individuals with lower values of mean body mass index.

CONCLUSIONS

Our data provide evidence that miRNAs are a molecular mechanism underlying the BP-related effects of air pollution exposure, and indicate miR-101 as epigenetic mechanism to be further investigated.

Visceral adiposity is associated with cytokines and decrease in lung function in women with persistent asthma

Abdominal obesity is associated with a risk of cardiovascular diseases, metabolic syndrome and decreased lung function. However, it is not known whether asthma control is influenced by the accumulation of adipose tissue in the various abdominal compartments.

OBJECTIVE

To determine associations among abdominal adiposity distribution, asthma control, lung function and cytokines in women.

METHODS AND DESIGN

In this cross-sectional study of asthmatic women, data on demographic variables, comorbid conditions, disease history, anthropometric and spirometric measurements were collected. Subcutaneous (SAT) and visceral (VAT) adipose tissues were measured by ultrasound, and the steatosis level was obtained. Asthma control was assessed according to Global Initiative for Asthma (GINA) criteria. Atopy was defined on the basis of allergen-specific Immunoglobulin E and/or skin prick testing. Cytokine levels were determined using enzyme-linked immunosorbant assays (ELISAs).

RESULTS

Eighty-three asthmatic women were included, 37% of whom had uncontrolled asthma. After controlling for variables, a negative association between asthma control and VAT and the VAT/SAT ratio was observed. VAT was negatively associated with respiratory parameters after controlling for explanatory variables. In an adjusted model, body mass index (BMI) and SAT were inversely associated with the adiponectin serum level and VAT was associated with the interleukin 6 level. In conclusion, visceral obesity was negatively associated with asthma control and lung function; and positively associated with increased levels of interleukin 6 in women. We hypothesize that women should be studied as a separate group, and we suggest further studies with a control group to know if the uncontrolled asthmatic group is directly affected by visceral adipose inflammatory markers.

DNA methylation and genetic polymorphisms of the Leptin gene interact to influence lung function outcomes and asthma at 18 years of age

The leptin gene (LEP) plays a regulatory role in satiety, inflammation, and allergy. Prior findings linking leptin to asthma motivated us to investigate whether DNA methylation (DNA-M) of CpG (cytosine-phosphate-guanine) sites in concert with single nucleotide polymorphisms (SNPs) of LEP can explain the risk of asthma and lung function. Methylation of CpG sites was assessed using the Illumina Infinium Human Methylation 450 beadchip in blood samples collected from 10- and 18-year-old boys and girls from the Isle of Wight (IOW) birth cohort (UK). Four LEP SNPs were genotyped. Linear and log linear models were used for the analysis, adjusting for false discovery rate (FDR). The analyses were repeated in the BAMSE cohort (Sweden). In the IOW study, the interaction of cg00666422 and rs11763517 (CT vs TT and CC) was associated with FEV1 (FDR-adjusted p-value: 0.03), FEV1/FVC ratio (FDR-adjusted p-value: 0.0096), and FEF25-75% (FDR-adjusted p-value: 0.00048) such that they decreased with increasing DNA-M. The interaction of the same CpG-SNP pair was also associated with increased risk of asthma at age 18. We replicated the findings for FEV1/FVC and FEF25-75% in a smaller sample of 34 participants at age 10. Regarding the BAMSE cohort, although, the interaction of cg00666422 and rs11763517 on lung function were not significant, the direction of the effect was the same as in IOW cohort. Thus, penetrance of LEP genotype seems to be modified by methylation at cg00666422 and is linked to airway obstruction and asthma.

Murine models of cardiovascular comorbidity in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk for cardiovascular disease (CVD). Currently, COPD patients with atherosclerosis (i.e., the most important underlying cause of CVD) receive COPD therapy complemented with standard CVD therapy. This may, however, not be the most optimal treatment. To investigate the link between COPD and atherosclerosis and to develop specific therapeutic strategies for COPD patients with atherosclerosis, a substantial number of preclinical studies using murine models have been performed. In this review, we summarize the currently used murine models of COPD and atherosclerosis, both individually and combined, and discuss the relevance of these models for studying the pathogenesis and development of new treatments for COPD patients with atherosclerosis. Murine and clinical studies have provided complementary information showing a prominent role for systemic inflammation and oxidative stress in the link between COPD and atherosclerosis. These and other studies showed that murine models for COPD and atherosclerosis are useful tools and can provide important insights relevant to understanding the link between COPD and CVD. More importantly, murine studies provide good platforms for studying the potential of promising (new) therapeutic strategies for COPD patients with CVD.

Signaling Interplay between Bone Marrow Adipose Tissue and Multiple Myeloma cells

In the year 2000, Hanahan and Weinberg (1) defined the six Hallmarks of Cancer as: self-sufficiency in growth signals, evasion of apoptosis, insensitivity to antigrowth mechanisms, tissue invasion and metastasis, limitless replicative potential, and sustained angiogenesis. Eleven years later, two new Hallmarks were added to the list (avoiding immune destruction and reprograming energy metabolism) and two new tumor characteristics (tumor-promoting inflammation and genome instability and mutation) (2). In multiple myeloma (MM), a destructive cancer of the plasma cell that grows predominantly in the bone marrow (BM), it is clear that all these hallmarks and characteristics are in play, contributing to tumor initiation, drug resistance, disease progression, and relapse. Bone marrow adipose tissue (BMAT) is a newly recognized contributor to MM oncogenesis and disease progression, potentially affecting MM cell metabolism, immune action, inflammation, and influences on angiogenesis. In this review, we discuss the confirmed and hypothetical contributions of BMAT to MM development and disease progression. BMAT has been understudied due to technical challenges and a previous lack of appreciation for the endocrine function of this tissue. In this review, we define the dynamic, responsive, metabolically active BM adipocyte. We then describe how BMAT influences MM in terms of: lipids/metabolism, hypoxia/angiogenesis, paracrine or endocrine signaling, and bone disease. We then discuss the connection between BMAT and systemic inflammation and potential treatments to inhibit the feedback loops between BM adipocytes and MM cells that support MM progression. We aim for researchers to use this review to guide and help prioritize their experiments to develop better treatments or a cure for cancers, such as MM, that associate with and may depend on BMAT.

Influence of Body Composition on Lung Function and Respiratory Muscle Strength in Children With Obesity

Background

Obesity affects lung function and respiratory muscle strength. The aim of the present study was to assess lung function and respiratory muscle strength in children with obesity and determine the influence of body composition on these variables.

Methods

A cross-sectional study was conducted involving 75 children (40 with obesity and 35 within the ideal weight range) aged 6 - 10 years. Body mass index, z score, waist circumference, body composition (tetrapolar bioimpedance), respiratory muscle strength and lung function (spirometry) were evaluated.

Results

Children with obesity exhibited larger quantities of both lean and fat mass in comparison to those in the ideal weight range. No significant differences were found between groups regarding the respective reference values for respiratory muscle strength. Male children with obesity demonstrated significantly lower lung function values (forced expiratory volume in the first second % (FEV₁%) and FEV₁/forced vital capacity % (FVC%) : 93.76 ± 9.78 and 92.29 ± 3.8, respectively) in comparison to males in the ideal weight range (99.87 ± 9.72 and 96.31 ± 4.82, respectively). The regression models demonstrated that the spirometric variables were influenced by all body composition variables.

Conclusion

Children with obesity demonstrated a reduction in lung volume and capacity. Thus, anthropometric and body composition characteristics may be predictive factors for altered lung function.

Adipokine CTRP-5 as a Potential Novel Inflammatory Biomarker in Chronic Obstructive Pulmonary Disease

Local and systemic inflammation often present in chronic obstructive pulmonary disease (COPD). Adipokines are secretory protein mediators by adipose tissue, which have been found to involve in inflammatory responses in many chronic inflammatory diseases. Therefore, we performed this preliminary clinical study to investigate the possible association between 2 adipokines, C1q/tumor necrosis factor-related protein-3 and -5 (CTRP-3 and CTRP-5), with lung function and other markers of inflammation in COPD. Serum CTRP-3 and CTRP-5 levels were measured in 73 COPD patients and 54 health controls, together with lung function and levels of adiponectin, CRP, TNF-α, and MPO in both groups. Pearson's partial correlation was used to analyze the correlations between CTRPs and other serum markers or lung function. Serum CTRP-5 was significantly elevated in COPD patients (0.41 ± 0.35 versus 0.29 ± 0.28 μg/ml, P = 0.01) and correlated inversely with FEV1/FVC ratio in all patients (r = -0.31, P = 0.001). In COPD patients, CTRP-5 was also correlated negatively with FEV1% predicted (r = -0.464, P < 0.001) and had a positive association with CRP levels (r = 0.262, P = 0.04). However, serum CTRP-3 levels were not correlated with measures of lung function or systemic inflammation. In conclusion, circulating CTRP-5 was associated with the severity of airflow obstruction and systemic inflammation in patients with COPD, which suggests that it may be used as a potential novel inflammatory biomarker in COPD. Further studies should be performed to clarify the exact role of CTRP-5 on the pathogenesis and outcomes of COPD.

Influence of Anthropometric Measurements in Lung Function in Patients With Asthma

Background:

Obesity is commonly regarded as a risk factor for asthma development, poor asthma control, and poor response to asthma therapy.

Methods:

In a cross-sectional study, 85 asthmatics (37 male and 48 female) participated. Pulmonary function tests (PFTs) and anthropometric parameters were measured for each patient.

Results:

Mean age and median duration were 43.9 ± 10.61 and 6 (3–14) years, respectively. Among anthropometric parameters, only waist-to-hip ratio (WHR) indicated significant correlation with PFTs in both sex (P < 0.05). There were negative associations between waist circumference, hip circumference and WHR with PFTs only in overweight and obese women (P < 0.05).

Conclusions:

Some anthropometric parameters affected lung function, and it seems that gender differentially contributes to this effect.

The mediating effect of body mass index on the relationship between cigarette smoking and atopic sensitization in Chinese adults

BACKGROUND

It is unclear whether the relationship between cigarette smoking and atopy is mediated by body fat mass, such as the Body Mass Index (BMI). We assessed the mediating role of BMI on the relationship between smoking and atopy in Chinese adults.

METHODS

A hospital-based case-control study of 786 atopic cases and 2771 controls was conducted in adults aged 18 years or older from March 2010 to September 2014 in Harbin, China. Mediation models were used to estimate the indirect effects of smoking on atopic sensitization through BMI.

RESULTS

Compared to non-smokers, light smokers and moderate smokers had a lower risk of inhalant allergen sensitization. The indirect effect of smoking and sensitization to aeroallergens were only observed in light smokers (point estimate, -0.026; 95% CI, -0.062 to -0.004). The mediating roles of BMI on the relationships between smoking and other types of allergic sensitization were not statistically significant.

CONCLUSION

BMI appeared to partially mediate the effect of light smoking on sensitization to aeroallergens. However, considering the other harmful health effects of cigarette smoking, the effective method to lower the incidence of atopy would be to decrease body fat mass by physical exercise and employing other more healthy ways of living rather than smoking.

Association of serum adiponectin with asthma and pulmonary function in the Japanese population

Conflicting findings have been reported regarding the role of adiponectin in asthma. The aim of this study was to evaluate the association of adiponectin with pulmonary functions and asthma in the Japanese population. First, among a general population that participated in a previous study (group 1), we selected 329 subjects after excluding those with asthma, chronic obstructive pulmonary disease, and a smoking history and examined the associations of the serum total adiponectin levels with pulmonary functions. In a second cohort (group 2) consisting of 61 asthmatic patients and 175 control non-asthmatic subjects, we examined the associations between asthma and the levels of total, high (HMW), middle (MMW) and low (LMW) molecular weight adiponectin isoforms as well as the ratio of each isoform to total adiponectin level. Although the total adiponectin levels were not significantly different between the asthmatic and control subjects in group 2, the levels were significantly and positively associated with the forced expiratory volume in 1 s after adjustments for confounding factors (P < 0.05) in women in group 1. In group 2, the LMW adiponectin level was significantly higher and the MMW/total adiponectin ratio was significantly lower among the asthmatic subjects than among the control subjects after adjustments for confounding factors in both sexes (P < 0.05). The present study showed that a low total adiponectin level may lead to airway narrowing compatible with asthmatic airways in women, and higher LMW adiponectin levels and lower MMW/total adiponectin ratio are significantly associated with current asthma in both sexes.