Obesity and lung inflammation

Omega-3 Fatty Acids and Chronic Lung Diseases: A Narrative Review of Impacts from Womb to Tomb

The lungs are a mucosal organ constantly exposed to potentially harmful compounds and pathogens. Beyond their role in gas exchange, they must perform a well-orchestrated protective response against foreign invaders. The lungs identify these foreign compounds, respond to them by eliciting an inflammatory response, and restore tissue homeostasis after inflammation to ensure the lungs continue to function. In addition, lung function can be affected by genetics, environmental exposures, and age, leading to pulmonary diseases that infringe on quality of life. Recent studies indicate that diet can influence pulmonary health including the incidence and/or severity of lung diseases. Specifically, long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) have gained attention because of their potential to reduce inflammation and promote resolution of inflammation. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two potentially beneficial n-3 PUFAs primarily acquired through dietary intake. Here we review current literature examining the role of n-3 PUFAs and the biological mechanisms by which these fatty acids alter the incidence and pathologies of chronic lung diseases including asthma, chronic obstructive pulmonary disease (COPD), and Interstitial Lung Disease (ILD). We also highlight the role of n-3 PUFAs in vulnerable populations such as pre/post-natal children, those with obesity, and the elderly. Lastly, we review the impact of n-3 PUFA intake and supplementation to evaluate if increasing consumption can mitigate mechanisms driving chronic lung diseases.

A Systematic Review of Metabolic Syndrome: Key Correlated Pathologies and Non-Invasive Diagnostic Approaches

Background and Objectives: Metabolic syndrome (MetS) is a condition marked by a complex array of physiological, biochemical, and metabolic abnormalities, including central obesity, insulin resistance, high blood pressure, and dyslipidemia (characterized by elevated triglycerides and reduced levels of high-density lipoproteins). The pathogenesis develops from the accumulation of lipid droplets in the hepatocyte (steatosis). This accumulation, in genetically predisposed subjects and with other external stimuli (intestinal dysbiosis, high caloric diet, physical inactivity, stress), activates the production of pro-inflammatory molecules, alter autophagy, and turn on the activity of hepatic stellate cells (HSCs), provoking the low grade chronic inflammation and the fibrosis. This syndrome is associated with a significantly increased risk of developing type 2 diabetes mellitus (T2D), cardiovascular diseases (CVD), vascular, renal, pneumologic, rheumatological, sexual, cutaneous syndromes and overall mortality, with the risk rising five- to seven-fold for T2DM, three-fold for CVD, and one and a half-fold for all-cause mortality. The purpose of this narrative review is to examine metabolic syndrome as a "systemic disease" and its interaction with major internal medicine conditions such as CVD, diabetes, renal failure, and respiratory failure. It is essential for internal medicine practitioners to approach this widespread condition in a "holistic" rather than a fragmented manner, particularly in Western countries. Additionally, it is important to be aware of the non-invasive tools available for assessing this condition. Materials and Methods: We conducted an exhaustive search on PubMed up to July 2024, focusing on terms related to metabolic syndrome and other pathologies (heart, Lung (COPD, asthma, pulmonary hypertension, OSAS) and kidney failure, vascular, rheumatological (osteoarthritis, rheumatoid arthritis), endocrinological, sexual pathologies and neoplastic risks. The review was managed in accordance with the PRISMA statement. Finally, we selected 300 studies (233 papers for the first search strategy and 67 for the second one). Our review included studies that provided insights into metabolic syndrome and non-invasive techniques for evaluating liver fibrosis and steatosis. Studies that were not conducted on humans, were published in languages other than English, or did not assess changes related to heart failure were excluded. Results: The findings revealed a clear correlation between metabolic syndrome and all the pathologies above described, indicating that non-invasive assessments of hepatic fibrosis and steatosis could potentially serve as markers for the severity and progression of the diseases. Conclusions: Metabolic syndrome is a multisystem disorder that impacts organs beyond the liver and disrupts the functioning of various organs. Notably, it is linked to a higher incidence of cardiovascular diseases, independent of traditional cardiovascular risk factors. Non-invasive assessments of hepatic fibrosis and fibrosis allow clinicians to evaluate cardiovascular risk. Additionally, the ability to assess liver steatosis may open new diagnostic, therapeutic, and prognostic avenues for managing metabolic syndrome and its complications, particularly cardiovascular disease, which is the leading cause of death in these patients.

Peripheral biomarkers as a predictor of poor prognosis in severe cases of COVID-19

We evaluated glycemia and triglyceride, hepatic, muscular, and renal damage markers, redox profile, and leptin and ghrelin hormone levels in COVID-19 patients. We also conducted statistical analysis to verify the potential of biomarkers to predict poor prognosis and the correlation between them in severe cases. We assessed glycemia and the levels of triglycerides, hepatic, muscular, and renal markers in automatized biochemical analyzer. The leptin and ghrelin hormones were assessed by the ELISA assay. Severe cases presented high glycemia and triglyceride levels. Hepatic, muscular, and renal biomarkers were altered in severe patients. Oxidative stress status was found in severe COVID-19 patients. Severe cases also had increased levels of leptin. The ROC curves indicated many biomarkers as poor prognosis predictors in severe cases. The Spearman analysis showed that biomarkers correlate between themselves. Patients with COVID-19 showed significant dysregulation in the levels of several peripheral biomarkers. We bring to light that a robust panel of peripheral biomarkers and hormones predict poor prognosis in severe cases of COVID-19 and biomarkers correlate with each other. Early monitoring of these biomarkers may lead to appropriate clinical interventions in patients infected by SARS-CoV2.

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.

Preserved Ratio Impaired Spirometry (PRISm): A Global Epidemiological Overview, Radiographic Characteristics, Comorbid Associations, and Differentiation from Chronic Obstructive Pulmonary Disease

Preserved Ratio Impaired Spirometry (PRISm) manifests notable epidemiological disparities across the globe, with its prevalence and influential factors showcasing pronounced diversities among various geographical territories and demographics. The prevalence of PRISm fluctuates considerably among regions such as Latin America, the United States, and Asian nations, potentially correlating with a myriad of determinants, including socioeconomic status, environmental factors, and lifestyle modalities. Concurrently, the link between PRISm and health risks and other disorders, especially its distinction and interrelation with chronic obstructive pulmonary disease (COPD), has become a pivotal subject of scientific enquiry. Radiographic anomalies, such as perturbations in the pulmonary parenchyma and structural alterations, are posited as salient characteristics of PRISm. Furthermore, PRISm unveils intricate associations with multiple comorbidities, inclusive of hypertension and type 2 diabetes, thereby amplifying the intricacy in comprehending and managing this condition. In this review, we aim to holistically elucidate the epidemiological peculiarities of PRISm, its potential aetiological contributors, its nexus with COPD, and its association with radiographic aberrations and other comorbidities. An integrative understanding of these dimensions will provide pivotal insights for the formulation of more precise and personalised preventative and therapeutic strategies.

Diabetes Mellitus, Energy Metabolism, and COVID-19

Obesity, diabetes mellitus (mostly type 2), and COVID-19 show mutual interactions because they are not only risk factors for both acute and chronic COVID-19 manifestations, but also because COVID-19 alters energy metabolism. Such metabolic alterations can lead to dysglycemia and long-lasting effects. Thus, the COVID-19 pandemic has the potential for a further rise of the diabetes pandemic. This review outlines how preexisting metabolic alterations spanning from excess visceral adipose tissue to hyperglycemia and overt diabetes may exacerbate COVID-19 severity. We also summarize the different effects of SARS-CoV-2 infection on the key organs and tissues orchestrating energy metabolism, including adipose tissue, liver, skeletal muscle, and pancreas. Last, we provide an integrative view of the metabolic derangements that occur during COVID-19. Altogether, this review allows for better understanding of the metabolic derangements occurring when a fire starts from a small flame, and thereby help reducing the impact of the COVID-19 pandemic.

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

Ultrastructural changes of lung tissue under conditions of experimental obesity and smoking

Obesity can cause respiratory disorders inflicted by adipose tissue accumulation and the numerous cytokines adipocytes produce. Smoking is, first of all, associated with a wide range of lung diseases characterized by diffuse changes in the lung tissue and a decrease in the respiratory volume of the lungs. The study aimed to investigate the ultrastructural changes in the lungs of sexually mature male rats under conditions of experimental obesity and smoking. The total sample of experimental animals consisted of 120 rats, divided into four groups: the control group (n=30) - conditionally healthy rats fed on a standard diet; a group of rats subjected to isolated exposure to tobacco smoke (n=30); a group of experimentally obese rats (n=30) and a group of experimentally obese rats simultaneously exposed to tobacco smoke (n=30) - feeding using a high-fat diet with exposure to a chamber with tobacco smoke. The revealed ultrastructural features of the lungs in the group of rats with experimental obesity and the group of rats with experimental obesity that were simultaneously exposed to tobacco smoke did not differ qualitatively, which indicates that pathological changes in the ultrastructure of the lung tissue developed regardless of the presence or absence of a direct damaging effect on the lung tissue of passive smoking.

Pneumosepsis survival in the setting of obesity leads to persistent steatohepatitis and metabolic dysfunction

BACKGROUND

As critical care practice evolves, the sepsis survivor population continues to expand, often with lingering inflammation in many organs, including the liver. Given the concurrently increasing population of patients with NAFLD, in this study, we aimed to understand the long-term effect of sepsis on pre-existing NAFLD and hyperglycemia.

METHODS

Male mice were randomized to a high-fat diet or a control diet (CD). After 24 weeks on diet, mice were inoculated with Klebsiella pneumoniae (Kpa). Serial glucose tolerance tests, and insulin and pyruvate challenge tests were performed 1 week before infection and at 2 and 6 weeks after infection. Whole tissue RNA sequencing and histological evaluation of the liver were performed. To test whether persistent inflammation could be reproduced in other abnormal liver environments, mice were also challenged with Kpa after exposure to a methionine-choline-deficient high-fat diet. Finally, a retrospective cohort of 65,139 patients was analyzed to evaluate whether obesity was associated with liver injury after sepsis.

RESULTS

After Kpa inoculation, high-fat diet mice had normalized fasting blood glucose without a change in insulin sensitivity but with a notable decrease in pyruvate utilization. Liver examination revealed focal macrophage collections and a unique inflammatory gene signature on RNA analysis. In the clinical cohort, preobesity, and class 1 and class 2 obesity were associated with increased odds of elevated aminotransferase levels 1-2 years after sepsis.

CONCLUSIONS

The combination of diet-induced obesity and pneumosepsis survival in a murine model resulted in unique changes in gluconeogenesis and liver inflammation, consistent with the progression of benign steatosis to steatohepatitis. In a cohort study, obese patients had an increased risk of elevated aminotransferase levels 1-2 years following sepsis.

Development of New Donor-Specific and Human Leukocyte Antigen Antibodies After Transfusion in Adult Lung Transplantation

OBJECTIVES

The development of new human leukocyte antigens (HLAs) and donor-specific antibodies (DSAs) in patients are associated with worse outcomes following lung transplantation. The authors aimed to examine the relationship between blood product transfusion in the first 72 hours after lung transplantation and the development of HLA antibodies, including DSAs.

DESIGN

A retrospective observational study.

SETTING

At a single academic tertiary center.

PARTICIPANTS

Adult lung transplant recipients who underwent transplantation between September 2014 and June 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 380 patients were included in this study, and 87 (23%) developed de novo donor-specific antibodies in the first year after transplantation. Eighty-five patients (22%) developed new HLA antibodies that were not donor-specific, and 208 patients (55%) did not develop new HLA antibodies in the first year after transplantation. Factors associated with increased HLA and DSA development included donor pulmonary infection, non-infectious indication for transplant, increased recipient body mass index, and a preoperative calculated panel reactive antibody value above 0. Multivariate analysis identified platelet transfusion associated with an increased risk of de novo HLA antibody development compared to the negative group (odds ratio [OR; 95% CI] 1.18 [1.02-1.36]; p = 0.025). Cryoprecipitate transfusion was associated with de novo DSA development compared to the negative group (OR [95% CI] 2.21 [1.32-3.69] for 1 v 0 units; p = 0.002).

CONCLUSIONS

Increased perioperative transfusion of platelets and cryoprecipitate are associated with de novo HLA and DSA development, respectively, in lung transplant recipients during the first year after transplantation.

A role of STING signaling in obesity-induced lung inflammation

BACKGROUND

It is established that pulmonary disorders are comorbid with metabolic disorders such as obesity. Previous studies show that the stimulator of interferon genes (STING) signaling plays crucial roles in obesity-induced chronic inflammation via TANK-binding kinase 1 (TBK1) pathways. However, it remains unknown whether and how the STING signaling is implicated in the inflammatory processes in the lung in obesity.

METHODS

Human lung tissues were obtained from obese patients (n = 3) and controls (n = 3). Mice were fed with the high-fat diet or regular control diet to establish the diet-induced obese (DIO) and lean mice, and were treated with C-176 (a specific STING inhibitor) or vehicle respectively. The lung macrophages were exposed to palmitic acid (PA) in vitro. The levels of STING singaling and metabolic inflammation factors were detected and anlyzed.

RESULTS

We find that STING+/CD68+ macrophages are increased in lung tissues in patients with obesity. Our data also show that the expressions of STING and the levels of proinflammatory cytokines are increased both in lung tissues and bronchoalveolar lavage fluid (BALF) in obesity compared to controls, and inhibition of the STING blunted the obesity-induced lung inflammation. Mechanistically, our data demonstrate that the STING signaling pathway is involved in the PA-induced inflammation through the STING-TBK1-IRF3 (interferon regulatory factor 3)/NF-κB (nuclear factor kappa B) pathways in the lung macrophages.

CONCLUSIONS

Our results collectively suggest that the STING signaling contributes to obesity-associated inflammation by stimulating proinflammatory processes in lung macrophages, one that may serve as a therapeutic target in ameliorating obesity-related lung dysfunctions.

Airway microbiota and immune mediator relationships differ in obesity and asthma

BACKGROUND

Asthma and obesity are both complex conditions characterized by chronic inflammation, and obesity-related severe asthma has been associated with differences in the microbiome. However, whether the airway microbiome and microbiota-immune response relationships differ between obese persons with or without nonsevere asthma is unestablished.

OBJECTIVE

We compared the airway microbiome and microbiota-immune mediator relationships between obese and nonobese subjects, with and without mild-moderate asthma.

METHODS

We performed cross-sectional analyses of the airway (induced sputum) microbiome and cytokine profiles from blood and sputum using 16S ribosomal RNA gene and internal transcribed spacer region sequencing to profile bacteria and fungi, and multiplex immunoassays. Analysis tools included QIIME 2, linear discriminant analysis effect size (aka LEfSe), Piphillin, and Sparse inverse covariance estimation for ecological association inference (aka SPIEC-EASI).

RESULTS

Obesity, irrespective of asthma status, was associated with significant differences in sputum bacterial community structure and composition (unweighted UniFrac permutational analysis of variance, P = .02), including a higher relative abundance of Prevotella, Gemella, and Streptococcus species. Among subjects with asthma, additional differences in sputum bacterial composition and fungal richness were identified between obese and nonobese individuals. Correlation network analyses demonstrated differences between obese and nonobese asthma in relationships between cytokine mediators, and these together with specific airway bacteria involving blood PAI-1, sputum IL-1β, GM-CSF, IL-8, TNF-α, and several Prevotella species.

CONCLUSION

Obesity itself is associated with an altered sputum microbiome, which further differs in those with mild-moderate asthma. The distinct differences in airway microbiota and immune marker relationships in obese asthma suggest potential involvement of airway microbes that may affect mechanisms or outcomes of obese asthma.

Association of body mass index and weight change with pneumonia mortality in a Japanese population: Japan Public Health Center-based Prospective Study

BACKGROUND

Accumulating evidence suggests that pneumonia mortality is lower for individuals with high body mass index (BMI) compared to normal BMI, but it remains unclear whether weight change during adulthood influences subsequent mortality due to pneumonia in Asian populations, who have a relatively lean body mass. This study aimed to examine the association of BMI and weight change over 5 years with the subsequent risk of pneumonia mortality in a Japanese population.

METHODS

The present analysis included 79,564 Japan Public Health Center (JPHC)-based Prospective Study participants who completed a questionnaire between 1995 and 1998 were followed for death through 2016. BMI was categorized into four groups: underweight (<18.5 kg/m²), normal weight (BMI: 18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obese (BMI: ≥30.0 kg/m²). Weight change was defined as the difference of body weight between questionnaire surveys with a 5-year interval. Cox proportional hazards regression was used to estimate hazard ratios of baseline BMI and weight change for pneumonia mortality.

RESULTS

During a median follow-up of 18.9 y, we identified 994 deaths from pneumonia. Compared with participants with normal weight, an elevated risk was observed among those who were underweight (hazard ratio = 2.29, 95% confidence interval [CI]: 1.83-2.87), whereas a decreased risk was found among those who were overweight (hazard ratio = 0.63, 95% CI: 0.53-0.75). Regarding weight change, the multivariable-adjusted hazard ratio (95% CI) of pneumonia mortality for a weight loss of 5 kg or more versus a weight change of less than 2.5 kg was 1.75 (1.46-2.10), whereas that for a weight gain of 5 kg or more was 1.59 (1.27-2.00).

CONCLUSION

Underweight and greater weight change was associated with an increase in the risk of pneumonia mortality in Japanese adults.

Associations of cardiorespiratory fitness and body mass index with incident restrictive spirometry pattern

OBJECTIVES

Restrictive spirometry pattern (RSP) suggests an impairment of lung function associated with a significantly increased risk of premature mortality. We evaluated the independent and joint associations of cardiorespiratory fitness (CRF) and body mass index with incident RSP.

METHODS

Data from the Aerobics Centre Longitudinal Study included 12 360 participants (18-82 years). CRF was assessed by maximal treadmill test and categorised into five groups. Body mass index was categorised into normal weight (<25.0 kg/m²), overweight (25.0-29.9 kg/m²) or obesity (≥30.0 kg/m²). RSP was defined as the simultaneous occurrence of forced expiratory volume in 1 s/force vital capacity ≥lower limit of normal and forced vital capacity <lower limit of normal.

RESULTS

There were 900 (7.3%) cases of RSP (mean follow-up: 6.9 years). Compared with category 1 ('least fit'), HRs (95% CIs) of RSP were 0.78 (0.63 to 0.96), 0.68 (0.54 to 0.86), 0.70 (0.55 to 0.88) and 0.59 (0.45 to 0.77) in categories 2, 3, 4 and 5 (most fit), respectively, after adjusting for confounders including body mass index. Compared with normal weight, HRs (95% CIs) of RSP were 1.06 (0.91 to 1.23) and 1.30 (1.03 to 1.64) in overweight and obese, respectively. However, the association between obesity and RSP was attenuated when additionally adjusting for CRF (HR 1.08, 95% CI 0.84 to 1.39). Compared with the 'unfit and overweight/obese' group, HRs (95% CIs) for RSP were 1.35 (0.98 to 1.85), 0.77 (0.63 to 0.96) and 0.70 (0.56 to 0.87) in the 'unfit and normal weight,' 'fit and overweight/obese' and 'fit and normal weight' groups, respectively.

CONCLUSIONS

Low CRF was associated with a greater incidence of RSP, irrespective of body mass index. Future studies are needed to explore potential underlying mechanisms of this association and to prospectively evaluate if improving CRF reduces the risk of developing RSP.

Relationship among Body Composition, Adipocytokines, and Irisin on Exercise Capacity and Quality of Life in COPD: A Pilot Study

Adipose tissue is an endocrine organ that interferes with the severity of chronic obstructive pulmonary disease (COPD). Although inflammatory markers, body composition, and nutritional status have a significant impact on pulmonary function, the real contribution of adipocytokines and myokines in COPD is still controversial. We aimed to evaluate the role played by the body composition, leptin, adiponectin, haptoglobin, and irisin on the functional exercise capacity, respiratory function, and quality of life (QoL) in COPD. In 25 COPD (20% GOLD-1; 60% GOLD-2; 20% GOLD-3) patients and 26 matched control subjects, we find that leptin, total adiponectin and haptoglobin are significantly increased whereas the 6 min walk test (6MWT) and physical functioning scores are significantly decreased in COPD versus controls. A significant positive relationship is found between leptin and fat mass and between 6MWT and the good health indicators of nutritional status. A significant inverse relationship is found between 6MWT and leptin and fat mass, FEV₁ and haptoglobin, and irisin and haptoglobin. Phase angle and leptin level are significant predictors for functional exercise capacity assessed with 6MWT. Taken altogether, the results of this pilot study further support the role played by body composition and adipocytokines on exercise capacity respiratory function and QoL in COPD.

Association between Pulmonary Function and Body Composition in Children and Adolescents with and without Obesity

Lung function in children and adolescents with obesity must consider the coexistence of two complex and related phenomena: obesity and growth. The assessment of body composition can identify changes in respiratory dynamics arising, exclusively or jointly, from adiposity and lean body mass. This study aimed to compare pulmonary function and the dysanapsis indices of children and adolescents without asthma, with and without obesity, considering body composition, pubertal development, and physical activity practice. We performed a cross-sectional study with 69 participants, 41 (59.42%) of whom have obesity. All participants carried out spirometry and the assessment of, respectively, body composition by dual-energy X-ray absorptiometry, vital signs, pubertal development, and physical activity practice. In our data, the group with obesity had higher values of forced vital capacity (FVC) and lower values of the ratio between forced expiratory volume in one second and FVC (FEV1/FVC). Analyzing the entire sample, we found a positive correlation between FVC and a negative correlation between FEV1/FVC with fat mass markers. At the same time, inspiratory capacity, expiratory reserve volume, and peak expiratory flow were correlated with lean body mass markers. In addition, participants with obesity presented a lower dysanapsis index. In conclusion, children and adolescents with obesity showed increased FVC and reduced FEV1/FVC. Our findings are possibly related to the increase in fat mass, not to lean body mass. We hypothesize that these findings are associated with the dysanaptic growth pattern, which is higher in obesity, evidenced by the reduction of the dysanapsis index.

Microbiome, Metabolism, and Immunoregulation of Asthma: An American Thoracic Society and National Institute of Allergy and Infectious Diseases Workshop Report

This report presents the proceedings from a workshop titled "Microbiome, Metabolism and Immunoregulation of Asthma" that was held virtually May 13 and 14, 2021. The workshop was jointly sponsored by the American Thoracic Society (Assembly on Allergy, Immunology, and Inflammation) and the National Institute of Allergy and Infectious Diseases. It convened an interdisciplinary group of experts with backgrounds in asthma immunology, microbiome science, metabolomics, computational biology, and translational pulmonary research. The main purpose was to identify key scientific gaps and needs to further advance research on microbial and metabolic mechanisms that may contribute to variable immune responses and disease heterogeneity in asthma. Discussions were structured around several topics, including 1) immune and microbial mechanisms of asthma pathogenesis in murine models, 2) the role of microbes in pediatric asthma exacerbations, 3) dysregulated metabolic pathways in asthma associated with obesity, 4) metabolism effects on macrophage function in adipose tissue and the lungs, 5) computational approaches to dissect microbiome-metabolite links, and 6) potential confounders of microbiome-disease associations in human studies. This report summarizes the major points of discussion, which included identification of specific knowledge gaps, challenges, and suggested directions for future research. These include questions surrounding mechanisms by which microbiota and metabolites shape host health versus an allergic or asthmatic state; direct and indirect influences of other biological factors, exposures, and comorbidities on these interactions; and ongoing technical and analytical gaps for clinical translation.

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

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

Association between Smoking Status and Incident Non-Cystic Fibrosis Bronchiectasis in Young Adults: A Nationwide Population-Based Study

Smoking traditionally has not been considered as a cause of bronchiectasis. However, few studies have evaluated the association between smoking and bronchiectasis. This study aimed to investigate the association between smoking status and bronchiectasis development in young adults. This study included 6,861,282 adults aged 20−39 years from the Korean National Health Insurance Service database 2009−2012 who were followed-up until the date of development of bronchiectasis, death, or 31 December 2018. We evaluated the incidence of bronchiectasis according to smoking status. During a mean of 7.4 years of follow-up, 23,609 (0.3%) participants developed bronchiectasis. In multivariable Cox regression analysis, ex-smokers (adjusted hazard ratio (aHR) = 1.07, 95% confidence interval (CI) = 1.03−1.13) and current-smokers (aHR = 1.06, 95% CI = 1.02−1.10) were associated with incident bronchiectasis, with the highest HR in ≥ 10 pack-years current smokers (aHR = 1.12, 95% CI = 1.06−1.16). The association of smoking with bronchiectasis was more profound in females than in males (p for interaction < 0.001), in younger than in older participants (p for interaction = 0.036), and in the overweight and obese than in the normal weight or underweight (p for interaction = 0.023). In conclusion, our study shows that smoking is associated with incident bronchiectasis in young adults. The association of smoking with bronchiectasis development was stronger in females, 20−29 year-olds, and the overweight and obese than in males, 30−40-year-olds, and the normal weight or underweight, respectively.

Community-based Lung Cancer Screening Results in Relation to Patient and Radiologist Characteristics: The PROSPR Consortium

Rationale: Lung-RADS classification was developed to standardize reporting and management of lung cancer screening using low-dose computed tomographic (LDCT) imaging. Although variation in Lung-RADS distribution between healthcare systems has been reported, it is unclear if this is explained by patient characteristics, radiologist experience with lung cancer screening, or other factors. Objectives: Our objective was to determine if patient or radiologist factors are associated with Lung-RADS score. Methods: In the Population-based Research to Optimize the Screening Process (PROSPR) Lung consortium, we conducted a study of patients who received their first screening LDCT imaging at one of the five healthcare systems in the PROSPR Lung Research Center from May 1, 2014, through December 31, 2017. Data on LDCT scans, patient factors, and radiologist characteristics were obtained via electronic health records. LDCT scan findings were categorized using Lung-RADS (negative [1], benign [2], probably benign [3], or suspicious [4]). We used generalized estimating equations with a multinomial distribution to compare the odds of Lung-RADS 3, and separately Lung-RADS 4, versus Lung-RADS 1 or 2 and estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between Lung-RADS assignment and patient and radiologist characteristics. Results: Analyses included 8,556 patients; 24% were assigned Lung-RADS 1, 60% Lung-RADS 2, 10% Lung-RADS 3, and 5% Lung-RADS 4. Age was positively associated with Lung-RADS 3 (OR, 1.02; 95% CI, 1.01-1.03) and 4 (OR, 1.03; 95% CI, 1.01-1.05); chronic obstructive pulmonary disease (COPD) was positively associated with Lung-RADS 4 (OR, 1.78; 95% CI, 1.45-2.20); obesity was inversely associated with Lung-RADS 3 (OR, 0.70; 95% CI, 0.58-0.84) and 4 (OR, 0.58; 95% CI, 0.45-0.75). There was no association between sex, race, ethnicity, education, or smoking status and Lung-RADS assignment. Radiologist volume of interpreting screening LDCT scans, years in practice, and thoracic specialty were also not associated with Lung-RADS assignment. Conclusions: Healthcare systems that are comprised of patients with an older age distribution or higher levels of COPD will have a greater proportion of screening LDCT scans with Lung-RADS 3 or 4 findings and should plan for additional resources to support appropriate and timely management of noted positive findings.

The Promising Mechanisms of Low Molecular Weight Compounds of Panax Ginseng C.A. Meyer in Alleviating COVID-19: A Network Pharmacology Analysis

Panax Ginseng C.A. Meyer (PGCAM) is a well-known phytomedicine, but most of its compounds, such as ginsenoside derivatives, have poor absorption and bioavailability profile due to high molecular weight (≥500 Daltons), which is the major hurdle for their clinical application. Hence, this research explored the efficiency of low molecular weight compounds (LMWCs) (<500 Daltons) screened from PGCAM and their anti-COVID-19 mechanisms through network pharmacology. Molecular compounds from PGCAM were identified using public databases and filtered out by the drug-likeness evaluation. Genes interacted with these filtered compounds, and COVID-19-related genes were extracted from public databases. In addition, overlapping genes between compounds and interactive genes were identified using the Venn diagram. In parallel, the networking between compounds and overlapping genes was analyzed by RStudio. The pathway enrichment analysis of overlapping genes was determined by STRING. Finally, the key bioactive compounds were documented through virtual screening. The bubble chart suggested that the mechanisms of PGCAM against COVID-19 were related to 28 signaling pathways. The key molecular anti-COVID-19 mechanisms might be the anti-inflammation, anti-permeability, and pro-apoptosis by inactivating the PI3K-Akt signaling pathway. The six key genes and the five compounds related to the PI3K-Akt signaling pathway were RELA-paeonol, NFKB1-frutinone A, IL6-nepetin, MCL1-ramalic acid, VEGFA-trifolirhizin, and IL2-trifolirhizin. The docking between these key genes and compounds demonstrated promising binding affinity with a good binding score. Overall, our proposed LMWCs from PGCAM provide a fundamental basis with noteworthy pharmacological evidence to support the therapeutic efficacy of PGCAM in relieving the main symptoms of COVID-19.

Mortality and Exacerbation Risk by Body Mass Index in Patients with COPD in TIOSPIR and UPLIFT

Rationale: There is an association between body mass index (BMI) and mortality in chronic obstructive pulmonary disease (COPD), with underweight individuals having higher mortality risk. Mortality and exacerbation risks among individuals with higher BMI are unclear. Objectives: To examine the relationship between BMI and adverse outcomes in COPD. Methods: This post hoc analysis included data from TIOSPIR (Tiotropium Safety and Performance in Respimat) (N = 17,116) and tiotropium-treated patients in UPLIFT (Understanding Potential Long-term Impacts on Function with Tiotropium) (N = 2,986). BMI classes (underweight [BMI < 20 kg/m2], normal weight [BMI 20 to <25 kg/m2], overweight [BMI 25 to <30 kg/m2], obesity class I [BMI 30 to <35 kg/m2], obesity class II [BMI 35 to <40 kg/m2], and obesity class III [BMI ⩾ 40 kg/m2]) were examined for adjusted associations with mortality, exacerbation, and nonfatal cardiovascular event risk using over 50,000 patient-years of cumulative follow-up data. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox regression models. Results: In TIOSPIR, obesity prevalence was 22%, overweight 32%, and underweight 12%. The proportion of females was highest in obesity classes II and III. Overweight and obese participants had better baseline lung function versus other BMI classes; underweight participants were more likely to be current smokers. Underweight participants had a significantly higher risk of death (HR, 1.88; 95% CI, 1.62-2.20; P < 0.0001) and severe exacerbations (HR, 1.31; 95% CI, 1.16-1.47; P < 0.0001) versus normal-weight participants; however, overweight and obese participants were at lower to no additional risk. Results from UPLIFT were similar to TIOSPIR. Conclusions: These results suggest that there is a strong association between body weight, COPD events, and risk of death. A holistic management approach taking into account respiratory and cardiovascular risk factors and nutritional status is needed to improve the general well-being of patients with COPD.

Mechanisms contributing to adverse outcomes of COVID-19 in obesity

A growing amount of epidemiological data from multiple countries indicate an increased prevalence of obesity, more importantly central obesity, among hospitalized subjects with COVID-19. This suggests that obesity is a major factor contributing to adverse outcome of the disease. As it is a metabolic disorder with dysregulated immune and endocrine function, it is logical that dysfunctional metabolism contributes to the mechanisms behind obesity being a risk factor for adverse outcome in COVID-19. Emerging data suggest that in obese subjects, (a) the molecular mechanisms of viral entry and spread mediated through ACE2 receptor, a multifunctional host cell protein which links to cellular homeostasis mechanisms, are affected. This includes perturbation of the physiological renin-angiotensin system pathway causing pro-inflammatory and pro-thrombotic challenges (b) existent metabolic overload and ER stress-induced UPR pathway make obese subjects vulnerable to severe COVID-19, (c) host cell response is altered involving reprogramming of metabolism and epigenetic mechanisms involving microRNAs in line with changes in obesity, and (d) adiposopathy with altered endocrine, adipokine, and cytokine profile contributes to altered immune cell metabolism, systemic inflammation, and vascular endothelial dysfunction, exacerbating COVID-19 pathology. In this review, we have examined the available literature on the underlying mechanisms contributing to obesity being a risk for adverse outcome in COVID-19.

Diet-induced obesity in mice impairs host defense against Klebsiella pneumonia in vivo and glucose transport and bactericidal functions in neutrophils in vitro

Obesity impairs host defense against Klebsiella pneumoniae, but responsible mechanisms are incompletely understood. To determine the impact of diet-induced obesity on pulmonary host defense against K. pneumoniae, we fed 6-wk-old male C57BL/6j mice a normal diet (ND) or high-fat diet (HFD) (13% vs. 60% fat, respectively) for 16 wk. Mice were intratracheally infected with Klebsiella, assayed at 24 or 48 h for bacterial colony-forming units, lung cytokines, and leukocytes from alveolar spaces, lung parenchyma, and gonadal adipose tissue were assessed using flow cytometry. Neutrophils from uninfected mice were cultured with and without 2-deoxy-d-glucose (2-DG) and assessed for phagocytosis, killing, reactive oxygen intermediates (ROI), transport of 2-DG, and glucose transporter (GLUT1-4) transcripts, and protein expression of GLUT1 and GLUT3. HFD mice had higher lung and splenic bacterial burdens. In HFD mice, baseline lung homogenate concentrations of IL-1β, IL-6, IL-17, IFN-γ, CXCL2, and TNF-α were reduced relative to ND mice, but following infection were greater for IL-6, CCL2, CXCL2, and IL-1β (24 h only). Despite equivalent lung homogenate leukocytes, HFD mice had fewer intraalveolar neutrophils. HFD neutrophils exhibited decreased Klebsiella phagocytosis and killing and reduced ROI to heat-killed Klebsiella in vitro. 2-DG transport was lower in HFD neutrophils, with reduced GLUT1 and GLUT3 transcripts and protein (GLUT3 only). Blocking glycolysis with 2-DG impaired bacterial killing and ROI production in neutrophils from mice fed ND but not HFD. Diet-induced obesity impairs pulmonary Klebsiella clearance and augments blood dissemination by reducing neutrophil killing and ROI due to impaired glucose transport.

BMI as a risk factor for the development of chronic rhinosinusitis: a prospective population-based study

PURPOSE

Obesity is a growing, global health problem and previous cross-sectional studies have demonstrated an association between obesity and chronic rhinosinusitis (CRS). There is, however, a lack of prospective studies regarding the impact of obesity on developing (new-onset) CRS.

METHODS

Questionnaire-based data (n = 5769) relating to new-onset CRS and Body Mass Index (BMI) were collected in 2013 and 2018 from the Telemark population study in Telemark, Norway. Odds ratios for the risk of new-onset CRS in 2018 in relation to BMI in 2013 were calculated, adjusted for smoking habits, asthma, gender and age.

RESULTS

When comparing the group with normal weight (18.5 ≤ BMI < 25) with the obese group (BMI ≥ 30), the odds of new-onset CRS was 53% higher [OR 1.53 (1.11, 2.10)] in the obese group.

CONCLUSION

CRS is a multifactorial disease with different phenotypes and it is important to consider obesity when assessing patients with CRS in a clinical setting.

25-Hydroxy vitamin D and body composition are associated with pulmonary function in non-cystic fibrosis bronchiectasis: A cross-sectional study

BACKGROUND

Previous studies have emphasized the effects of vitamin D on the lung function of cystic fibrosis (CF) adult patients. The main aim of the present study sought to determine the association between circulating 25-hydroxyvitamin D (25-OH D) concentration and clinical outcomes in non-cystic fibrosis (non-CF) bronchiectasis subjects. Secondary, we assessed the possible relationship between body composition and respiratory dysfunction in these patients.

MATERIALS AND METHODS

Sixty-two non-CF bronchiectasis patients (24 male/38 female), aged 18-72, were recruited in this cross-sectional study. Anthropometric indices, lung function tests, and bronchiectasis severity valuations were determined. Body composition, including Mid-arm muscle circumference (MAMC, cm) was calculated using triceps skinfold (TSF,mm) and mid-arm circumference (MAC,cm) under the reference formula. Then serum 25-hydroxyvitamin D concentration and C-reactive protein level were measured. The correlation between vitamin D level and pulmonary function and disease exacerbation tests was primarily assessed. Additionally, we evaluated the correlation between body composition and lung function tests.

RESULTS

Circulating 25-hydroxyvitamin D status positively was correlated with lung function tests, including FEV₁ (r = 0.30, p value = 0.035) and FVC (r = 0.36, p value = 0.011), and also be associated with the extent of pulmonary involvement (r = -0.34, p value = 0.03). There was a significant negative correlation between percentage body fat and respiratory function, FEV₁/FVC ratio (r = -0.43, p value < 0.001). In contrast, there was a strong correlation between skeletal muscle mass and pulmonary function tests (r = 0.26, p value = 0.04).

CONCLUSION

There is a positive association between low 25-hydroxyvitamin D status and lung dysfunction in participants with non-CF bronchiectasis. The pulmonary dysfunction also correlated with more percentage body fat and low skeletal muscle mass in these patients. Therefore, the evaluation of body composition and serum vitamin D are suggested in the disease management of the patients with non-CF bronchiectasis. However, these associations should be interpreted with caution due to the likelihood of reverse causation. More high-quality prospective studies are warranted to confirm our observations and determine the mechanisms underlying these findings.

Association between Dietary Patterns and Chronic Obstructive Pulmonary Disease in Korean Adults: The Korean Genome and Epidemiology Study

In addition to smoking, dietary habits may contribute to the development of chronic obstructive pulmonary disease (COPD). This study aimed to examine the association between dietary patterns and lung function in a Korean community cohort. A total of 5436 participants were included from the Ansan–Ansung cohort study. To identify the dietary patterns, we performed principal component factor analysis using the results of a semi-quantitative food frequency questionnaire. The forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio were measured by spirometry. Multiple logistic regression models were used to evaluate the association between dietary patterns and lung function after adjusting for confounders. We identified four major dietary patterns; ‘prudent’, ‘coffee, fat, and sweet’, ‘westernized’, and ‘white rice’. After adjusting for potential confounders, the ‘coffee, fat, and sweet’ dietary pattern was negatively associated with lung function, particularly the FEV1/FVC ratio. Participants with high scores for the ‘coffee, fat and sweet’ pattern had a higher risk of COPD among men but not women. Therefore, these results indicate that the ‘coffee, fat and sweet’ dietary pattern is inversely related to lung function in Korean adults. Our results indicate that dietary habits may be modifiable risk factors for COPD.

Hyperlipidemia and Obesity's Role in Immune Dysregulation Underlying the Severity of COVID-19 Infection

Obesity and hyperlipidemia are known to be risk factors for various pathological disorders, including various forms of infectious respiratory disease, including the current Coronavirus outbreak termed Coronavirus Disease 19 (COVID-19). This review studies the effects of hyperlipidemia and obesity on enhancing the inflammatory response seen in COVID-19 and potential therapeutic pathways related to these processes. In order to better understand the underlying processes of cytokine and chemokine-induced inflammation, we must further investigate the immunomodulatory effects of agents such as Vitamin D and the reduced form of glutathione as adjunctive therapies for COVID-19 disease.

Impact of obesity and ovariectomy on respiratory function in female mice

Obesity and the corresponding variations in female sex hormones are associated with severe lung disease. We determined the potential effects of obesity and sex hormones in female mice by investigating changes in lung structure and respiratory function in an obesity model induced by postnatal overnutrition. Obese female mice exhibited pronounced weight gain, abdominal fat accumulation and collagen type I deposition in the airways. However, neither elastic tissue nor estrogen receptors-α/-β were affected in obese female mice after ovariectomy or sham-operated mice. Bronchoconstriction in response to methacholine challenge in obese sham-operated mice was higher than in the obese group after ovariectomy. Our results suggest that the coexistence of obesity and ovariectomy impacted on respiratory system and airway resistance (attenuates bronchoconstriction after methacholine), on collagen I deposition and on airway estrogen β-receptors of mice.

Obesity and Health-Related Quality of Life in Children Hospitalized for Acute Respiratory Illness

OBJECTIVES

Obesity has rapidly become a major problem for children that has adverse effects on respiratory health. We sought to assess the impact of obesity on health-related quality of life (HRQOL) and hospital outcomes for children hospitalized with asthma or pneumonia.

METHODS

In this multicenter prospective cohort study, we evaluated children (aged 2-16 years) hospitalized with an acute asthma exacerbation or pneumonia between July 1, 2014, and June 30, 2016. Subjects or their family completed surveys for child HRQOL (PedsQL Physical Functioning and Psychosocial Functioning Scales, with scores ranging from 0 to 100) on hospital presentation and 2-6 weeks after discharge. BMI categories were defined as normal weight, overweight, and obesity on the basis of BMI percentiles for age and sex per national guidelines. Multivariable regression models were used to examine associations between BMI category and HRQOL, length of stay, and 30-day reuse.

RESULTS

Among 716 children, 82 (11.4%) were classified as having overweight and 138 (19.3%) as having obesity. For children hospitalized with asthma or pneumonia, obesity was not associated with worse HRQOL at presentation or 2-6 weeks after discharge, hospital length of stay, or 30-day reuse.

CONCLUSIONS

Nearly 1 in 3 children seen in the hospital for an acute asthma exacerbation or pneumonia had overweight or obesity; however, among the population of children in our study, obesity alone does not appear to be associated with worse HRQOL or hospital outcomes.

Association between abdominal obesity and pulmonary function in apparently healthy adults: A systematic review

BACKGROUND

Obesity, especially abdominal obesity as a chronic disorder is associated with a high risk of developing non-communicable diseases such as respiratory diseases. Impaired lung function is a sign of early respiratory injury. This review summarizes the current knowledge of the effects of abdominal obesity on pulmonary function in apparently healthy adults.

METHODS

Google Scholar, PubMed, Science Direct, and Scopus databases were searched from 2014 up to August 2020 using relevant keywords. All original articles written in English evaluating the effects of abdominal obesity on pulmonary function in apparently healthy adults were eligible for this review.

RESULTS

A total of 26 studies (23 cross-sectional and three cohort) involving 68,024 participants were included in this review. More than 88% of the included studies reported that abdominal obesity significantly inversely was associated with pulmonary function.

CONCLUSION

The findings indicate that in subjects with abdominal obesity respiratory function decline possibly due to mechanical compression and obesity-induced airway inflammation. Therefore, nutrition and lifestyle interventions are required for the reduction of abdominal obesity that leads to improving pulmonary function and metabolic disease.

Clinical considerations in providing intravenous sedation with midazolam for obese patients in dentistry

The widespread prevalence of obesity continues to rise. Obesity and dental disease share common risk factors and so the demand for dental care for obese patients is escalating. For some of these patients, there is a corresponding need to be able to provide intravenous sedation safely when it is necessary and appropriate to do so. However, obesity often presents with multiple comorbidities and airway complexities, leading to more challenging management and potentially increased risk. The risk assessment process as well as patient monitoring and management strategies will be explored in this article. By reviewing the literature from dentistry and other medical specialties, we also aim to establish the potential benefit in administering supplemental oxygen and the use of capnography in monitoring this cohort of patients.

Causal Effects of Body Mass Index on Airflow Obstruction and Forced Mid-Expiratory Flow: A Mendelian Randomization Study Taking Interactions and Age-Specific Instruments Into Consideration Toward a Life Course Perspective

Obesity has complex links to respiratory health. Mendelian randomization (MR) enables assessment of causality of body mass index (BMI) effects on airflow obstruction and mid-expiratory flow. In the adult SAPALDIA cohort, recruiting 9,651 population-representative samples aged 18–60 years at baseline (female 51%), BMI and the ratio of forced expiratory volume in 1 second (FEV₁) to forced vital capacity (FVC) as well as forced mid-expiratory flow (FEF25–75%) were measured three times over 20 follow-up years. The causal effects of BMI in childhood and adulthood on FEV1/FVC and FEF25–75% were assessed in predictive (BMI averaged over 1st and 2nd, lung function (LF) averaged over 2nd and 3rd follow-up; N = 2,850) and long-term cross-sectional models (BMI and LF averaged over all follow-ups; N = 2,728) by Mendelian Randomization analyses with the use of weighted BMI allele score as an instrument variable and two-stage least squares (2SLS) method. Three different BMI allele scores were applied to specifically capture the part of BMI in adulthood that likely reflects tracking of genetically determined BMI in childhood. The main causal effects were derived from models containing BMI (instrumented by BMI genetic score), age, sex, height, and packyears smoked as covariates. BMI interactions were instrumented by the product of the instrument (BMI genetic score) and the relevant concomitant variable. Causal effects of BMI on FEV1/FVC and FEF25–75% were observed in both the predictive and long-term cross-sectional models. The causal BMI- LF effects were negative and attenuated with increasing age, and stronger if instrumented by gene scores associated with childhood BMI. This non-standard MR approach interrogating causal effects of multiplicative interaction suggests that the genetically rooted part of BMI patterns in childhood may be of particular relevance for the level of small airway function and airflow obstruction later in life. The methodological relevance of the results is first to point to the importance of a life course perspective in studies on the etiological role of BMI in respiratory health, and second to point out novel methodological aspects to be considered in future MR studies on the causal effects of obesity related phenotypes.

A systematic review and meta-analysis of obesity and COVID-19 outcomes

Some studies report that obesity is associated with more severe symptoms following SARS-CoV-2 infection and worse COVID-19 outcomes, however many other studies have not reproduced these findings. Therefore, it is uncertain whether obesity is in fact associated with worse COVID-19 outcomes compared to non-obese individuals. We conducted a systematic search of PubMed (including MEDLINE) and Google Scholar on May 18, 2020 to identify published studies on COVID-19 outcomes in non-obese and obese patients, covering studies published during the first 6 months of the pandemic. Meta-analyses with random effects modeling was used to determine unadjusted odds ratios (OR) and 95% confidence intervals (CI) for various COVID-19 outcomes in obese versus non-obese patients. By quantitative analyses of 22 studies from 7 countries in North America, Europe, and Asia, we found that obesity is associated with an increased likelihood of presenting with more severe COVID-19 symptoms (OR 3.03, 95% CI 1.45-6.28, P = 0.003; 4 studies, n = 974), developing acute respiratory distress syndrome (ARDS; OR 2.89, 95% CI 1.14-7.34, P = 0.025; 2 studies, n = 96), requiring hospitalization (OR 1.68, 95% CI 1.14-1.59, P < 0.001; 4 studies, n = 6611), being admitted to an intensive care unit (ICU; OR 1.35, 95% CI 1.15-1.65, P = 0.001; 9 studies, n = 5298), and undergoing invasive mechanical ventilation (IMV; OR 1.76, 95% CI 1.29-2.40, P < 0.001; 7 studies, n = 1558) compared to non-obese patients. However, obese patients had similar likelihoods of death from COVID-19 as non-obese patients (OR 0.96, 95% CI 0.74-1.25, P = 0.750; 9 studies, n = 20,597). Collectively, these data from the first 6 months of the pandemic suggested that obesity is associated with a more severe COVID-19 disease course but may not be associated with increased mortality.

Effects of Obesity on Airway and Systemic Inflammation in Asthmatic Children

BACKGROUND

Obese asthma is a complex syndrome with certain phenotypes that differ in children and adults. There is no clear evidence regarding the presence of additive or synergistic pathological interaction between obesity and asthma in children.

OBJECTIVES

Our aim was to demonstrate the interaction of obesity and asthma in children in terms of airway and systemic inflammation by a controlled observational study.

METHODS

Four groups were formed: asthma obese (AO), asthma nonobese (ANO), non-AO (NAO), nonasthma nonobese (NANO). Spirometry test, fractional exhaled nitric oxide (FeNO) test, skin prick test, serum inflammatory biomarkers (C-reactive protein, C3, C4, adiponectin, leptin, resistin, periostin, YKL-40, Type 1, and Type 2 cytokines) were conducted and evaluated in all participants. Sputum inflammatory cells (sputum eosinophils and neutrophils) were evaluated in patients who could produce induced sputum and obesity-asthma interactions were determined.

RESULTS

A total of 153 participants aged 6-18 years were included in the study, including the AO group (n = 46), the ANO group (n = 45), the NAO group (n = 30), and the NANO group (n = 32). IL-4 (p < 0.001), IL-5 (p < 0.001), IL-13 (p < 0.001), resistin (p < 0.001), and YKL-40 (p < 0.001) levels were higher in patients with asthma independent of obesity. The lowest adiponectin level was found in the AO group and obesity-asthma interaction was detected (p < 0.001). Sputum eosinophilia (p < 0.01), sputum neutrophilia (p < 0.01), and FeNO levels (p = 0.07) were higher in asthmatic patients independent of obesity. In the group with paucigranulocytic inflammation, resistin and YKL-40 levels were significantly lower than in the group without paucigranulocytic inflammation (p < 0.01).

CONCLUSION

No interaction was found between obesity and asthma in terms of airway inflammation. Interaction between obesity and asthma was shown in terms of adiponectin level and resistin/adiponectin and leptin/adiponectin ratios. It was found that serum YKL-40 and resistin levels could be associated with airway inflammation.

Ketogenic Diet as a Preventive and Supportive Care for COVID-19 Patients

Severe obesity is associated with an increased risk of admission to intensive care units and need for invasive mechanical ventilation in patients with COVID-19. The association of obesity and COVID-19 prognosis may be related to many different factors, such as chronic systemic inflammation, the predisposition to severe respiratory conditions and viral infections. The ketogenic diet is an approach that can be extremely effective in reducing body weight and visceral fat in the short term, preserving the lean mass and reducing systemic inflammation. Therefore, it is a precious preventive measure for severely obese people and may be considered as an adjuvant therapy for patients with respiratory compromise.

Obesity is associated with severe COVID-19 but not death: a dose-response meta-analysis

The coronavirus disease 2019 (COVID-19) epidemic is spreading globally. Studies revealed that obesity may affect the progression and prognosis of COVID-19 patients. The aim of the meta-analysis is to identify the prevalence and impact of obesity on COVID-19. Studies on obese COVID-19 patients were obtained by searching PubMed, Cochrane Library databases and Web of Science databases, up to date to 5 June 2020. And the prevalence rate and the odds ratio (OR) of obesity with 95% confidence interval (CI) were used as comprehensive indicators for analysis using a random-effects model. A total of 6081 patients in 11 studies were included. The prevalence of obesity in patients with COVID-19 was 30% (95% CI 21-39%). Obese patients were 1.79 times more likely to develop severe COVID-19 than non-obese patients (OR 1.79, 95% CI 1.52-2.11, P < 0.0001, I2 = 0%). However obesity was not associated with death in COVID-19 patients (OR 1.05, 95% CI 0.65-1.71, P = 0.84, I2 = 66.6%). In dose-response analysis, it was estimated that COVID-19 patients had a 16% increased risk of invasive mechanical ventilation (OR 1.16, 95% CI 1.10-1.23, P < 0.0001) and a 20% increased risk of admission to ICU (OR 1.20, 95% CI 1.11-1.30, P < 0.0001) per 5 kg/m2 increase in BMI. In conclusion, obesity in COVID-19 patients is associated with severity, but not mortality.

Is obesity the missing link between COVID-19 severity and air pollution?

In the previous publication "Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?" Conticini et al. hypothesized that the surplus of lethality of the novel SARS-CoV-2 in Northern Italy may be at least in part explained by the evidence of highest pollution reported in this area, as both severe COVID-19 and smog exposure are correlated to an innate immune system hyper-activation with subsequent lung inflammation and injury. Since this hypothesis alone does not fully explain why specific subgroups of patients are at major risk, we hypothesized that obesity may be one of the links between COVID-19 severity and high level of air pollution. First, obesity is a predisposing factor for SARS-Cov-2 infection and worse COVID-19 outcomes, and unequivocal evidence demonstrated that fat mass excess is independently associated with several pulmonary diseases and lung inflammation. Moreover, it has been shown that obesity may intensify the detrimental effects of air pollution on the lungs, and this is not surprising if we consider that these conditions share an excessive activation of the immune system and a lung inflammatory infiltrate. Finally, fat mass excess has also been speculated to be itself a consequence of air pollutants exposure, which has been proved to induce metabolic disruption and weight gain in murine models. In conclusion, although many variables must be taken into account in the analysis of the pandemic, our observations suggest that obesity may act as effect modifier of smog-induced lung-injury, and the concomitant presence of these two factors could better explain the higher virulence, faster spread and greater mortality of SARS-CoV-2 in Northern Italy compared to the rest of the country.

The Effect of Adiposity Markers on Fractional Exhaled Nitric Oxide (FeNO) and Pulmonary Function Measurements

Background

The effect of increasing body weight on pulmonary function and the fractional exhaled nitric oxide (FeNO) remains controversial and the role of different body compositions in the relationship between obesity with pulmonary function and FeNO is still unrevealed. Thus, we aim to determine the effect of overweight/obesity on lung function and FeNO, focusing on the relationship with different body compositions.

Methods

Eighty-two non-smoker students (20 ± 1.9 years) were divided into two groups: 38 subjects with normal weight (BMI = 18.5–24.99) and 44 overweight/obese subjects (BMI ≥ 25). Spirometric parameters and FeNO were measured and compared between groups and were correlated with different adiposity markers.

Results

FeNO measurements were elevated in the overweight/obese group [median (IQR) 19.5 (13)] in comparison to the normal weight group [11 (10), p value = 0.017]. A positive correlation was found between FeNO measurements and body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, and visceral fat percentage (all p values < 0.01). The absolute values of forced vital capacity (FVC) forced expiratory volume in the first second (FEV₁), peak expiratory flow (PEF), forced expiratory flow during mid-expiration (FEF_25–75%), and FEV₁/FVC ratio showed no significant differences between groups. However, the percentage of the predicted values of FEV₁ and FVC was significantly higher and the value of percentage predicted FEF_25–75% was reduced significantly in the overweight/obese subjects.

Conclusion

Increase in BMI could significantly increase airway inflammation as measured by FeNO, as well as on distal airway function as determined by the percentage predicted values of FEF_25–75%. A significant correlation was also identified between visceral fat and FeNO measurement.

Lung function in obese children and adolescents without respiratory disease: a systematic review

BACKGROUND

Obesity in children and adolescents is associated with increased morbidity and mortality due to multisystemic impairment, including deleterious changes in lung function, which are poorly understood.

OBJECTIVES

To perform a systematic review to assess lung function in children and adolescents affected by obesity and to verify the presence of pulmonary changes due to obesity in individuals without previous or current respiratory diseases.

METHODS

A systematic search was performed in the MEDLINE-PubMed (Medical Literature Analysis and Retrieval System Online), Embase (Excerpta Medica Database) and VHL (Virtual Health Library/Brazil) databases using the terms "Lung Function" and "Pediatric Obesity" and their corresponding synonyms in each database. A period of 10 years was considered, starting in February/2008. After the application of the filters, 33 articles were selected. Using the PICOS strategy, the following information was achieved: (Patient) children and adolescents; (Intervention/exposure) obesity; (Control) healthy children and adolescents; (Outcome) pulmonary function alterations; (Studies) randomized controlled trial, longitudinal studies (prospective and retrospective studies), cross-over studies and cross-sectional studies.

RESULTS

Articles from 18 countries were included. Spirometry was the most widely used tool to assess lung function. There was high variability in lung function values, with a trend towards reduced lung function markers (FEV1/FVC, FRC, ERV and RV) in obese children and adolescents.

CONCLUSION

Lung function, measured by several tools, shows numerous markers with contradictory alterations. Differences concerning the reported results of lung function do not allow us to reach a consensus on lung function changes in children and adolescents with obesity, highlighting the need for more publications on this topic with a standardized methodology.

High-fat diet-induced obesity affects alpha 7 nicotine acetylcholine receptor expressions in mouse lung myeloid cells

Ample evidence indicates that obesity causes dysfunctions in the lung. Previous studies also show that cholinergic anti-inflammatory pathways play crucial roles in obesity-induced chronic inflammation via α7 nicotinic acetylcholine receptor (α7nAChR) signaling. However, it remains unclear whether and how obesity affects the expressions of α7nAChR in myeloid cells in the lung. To address this question, we treated regular chow diet-fed mice or high-fat diet induced obese mice with lipopolysaccharide (LPS) or vehicle via endotracheal injections. By using a multicolor flow cytometry approach to analyze and characterize differential cell subpopulations and α7nAChR expressions, we find no detectable α7nAChR in granulocytes, monocytes and alveolar macrophages, and low expression levels of α7nAChR were detected in interstitial macrophages. Interestingly, we find that a challenge with LPS treatment significantly increased expression levels of α7nAChR in monocytes, alveolar and interstitial macrophages. Meanwhile, we observed that the expression levels of α7nAChR in alveolar and interstitial macrophages in high-fat diet induced obese mice were lower than regular chow diet-fed mice challenged by the LPS. Together, our findings indicate that obesity alters the expressions of α7nAChR in differential lung myeloid cells.

Scientific evidence underlying contraindications to the ketogenic diet: An update

First identified as a feasible treatment for intractable epilepsy, the ketogenic diet (KD) has recently gained popularity thanks to growing evidence on applications such as weight loss, most importantly, but also NAFLD, cancer, neurologic conditions and chronic pain. As with any treatment, whether pharmacologic or not, the KD might not be an appropriate intervention for every individual, and a number of contraindications have been proposed, now deeply rooted into clinical practice, excluding de facto many patients that could benefit from its use. However, many of these concerns were expressed due to the absence of clinical studies conducted on fragile populations, and an assessment of lately emerged evidence relative to KD safety is currently lacking and much needed. We herein provide a critical revision of the literature behind each safety alert, in order to guide through the treatment options in the case of subjects with an indication to the KD and a borderline safe situation. Based on available evidence, the possible use of this diet as a therapeutic intervention should be assessed on a patient-to-patient basis by adequately skilled medical doctors, keeping in mind current recommendations, but reading them through the knowledge of the current state of the art.

Obesity and SARS-CoV-2: A population to safeguard

Evidence has lately emerged regarding an increased risk of SARS-CoV-2 with worse prognosis in patients with obesity, especially among the young. Weight excess is a well-established respiratory disease risk factor, and the newly reported correlation is therefore unsurprising. The underlying pathophysiology is likely multi-stranded, ranging from complement system hyperactivation, increased Interleukin-6 secretion, chronic inflammation, presence of comorbidities such as diabetes and hypertension, and a possible local, detrimental effect within the lung. Further understanding the link between obesity and SARS-CoV-2 is crucial, as this could aid proper tailoring of immunomodulatory treatments, together with improving stratification among those possibly requiring critical care.

Ambient air pollution and body weight status in adults: A systematic review and meta-analysis

Overweight and obesity have become a global epidemic and concern, and contributed to at least 4.0 million deaths each year worldwide. However, current evidence regarding the impact of air pollution on body weight status remains inconsistent. We therefore conducted a systematic review and meta-analysis to evaluate the effect of long-term exposure to ambient air pollutants on body weight status in adults. Three databases were searched up to Dec 31, 2019 for articles investigating the association of gaseous (sulfur dioxide, nitrogen dioxide, ozone) and particulate (diameter ≤ 10 μm or ≤ 2.5 μm) air pollutants with body weight status. Random effect models were used to estimate the pooled odds ratios (ORs), regression coefficients (β) and their 95% confidence intervals (95% CIs) associated with air pollution. Among twelve studies that were eligible in the systematic review, ten were used to estimate the pooled effect size, and most of them were cross-sectional studies. We identified that ambient air pollution had adverse effects on body weight status. For example, elevated PM_2.5 and O₃ were associated with higher level of body mass index, with the pooled β (95% CIs) of 0.34 (0.30-0.38) and 0.21 (0.17-0.24) per 10 μg/m³ increment, respectively. In addition, increased NO₂, SO₂ and O₃ were associated with higher risk of having overweight/obesity, with the corresponding pooled OR (95% CI) of 1.13 (1.01-1.26), 1.04 (1.01-1.06) and 1.07 (1.02-1.13) per 10 μg/m³ increment. Overall, air pollution is a potential risk factor for body weight status in adults, and more high-quality studies, especially prospective studies from severely polluted regions, are warranted for comprehensive understanding of its health effects.

Influence of obesity on remodeling of lung tissue and organization of extracellular matrix after blunt thorax trauma

Background

Previously, it has been shown that obesity is a risk factor for recovery, regeneration, and tissue repair after blunt trauma and can affect the rate of muscle recovery and collagen deposition after trauma. To date, lung tissue regeneration and extracellular matrix regulation in obese mice after injury has not been investigated in detail yet.

Methods

This study uses an established blunt thorax trauma model to analyze morphological changes and alterations on gene and protein level in lean or obese (diet-induced obesity for 16 ± 1 week) male C57BL/6 J mice at various time-points after trauma induction (1 h, 6 h, 24 h, 72 h and 192 h).

Results

Morphological analysis after injury showed lung parenchyma damage at early time-points in both lean and obese mice. At later time-points a better regenerative capacity of lean mice was observed, since obese animals still exhibited alveoli collapse, wall thickness as well as remaining filled alveoli structures. Although lean mice showed significantly increased collagen and fibronectin gene levels, analysis of collagen deposition showed no difference based on colorimetric quantification of collagen and visual assessment of Sirius red staining. When investigating the organization of the ECM on gene level, a decreased response of obese mice after trauma regarding extracellular matrix composition and organization was detectable. Differences in the lung tissue between the diets regarding early responding MMPs (MMP8/9) and late responding MMPs (MMP2) could be observed on gene and protein level. Obese mice show differences in regulation of extracellular matrix components compared to normal weight mice, which results in a decreased total MMP activity in obese animals during the whole regeneration phase. Starting at 6 h post traumatic injury, lean mice show a 50% increase in total MMP activity compared to control animals, while MMP activity in obese mice drops to 50%.

Conclusions

In conclusion, abnormal regulation of the levels of extracellular matrix genes in the lung may contribute to an aberrant regeneration after trauma induction with a delay of repair and pathological changes of the lung tissue in obese mice.

Obesity and COVID-19: Molecular Mechanisms Linking Both Pandemics

The coronavirus disease 2019 COVID-19 pandemic is rapidly spreading worldwide and is becoming a major public health crisis. Increasing evidence demonstrates a strong correlation between obesity and the COVID-19 disease. We have summarized recent studies and addressed the impact of obesity on COVID-19 in terms of hospitalization, severity, mortality, and patient outcome. We discuss the potential molecular mechanisms whereby obesity contributes to the pathogenesis of COVID-19. In addition to obesity-related deregulated immune response, chronic inflammation, endothelium imbalance, metabolic dysfunction, and its associated comorbidities, dysfunctional mesenchymal stem cells/adipose-derived mesenchymal stem cells may also play crucial roles in fueling systemic inflammation contributing to the cytokine storm and promoting pulmonary fibrosis causing lung functional failure, characteristic of severe COVID-19. Moreover, obesity may also compromise motile cilia on airway epithelial cells and impair functioning of the mucociliary escalators, reducing the clearance of severe acute respiratory syndrome coronavirus (SARS-CoV-2). Obese diseased adipose tissues overexpress the receptors and proteases for the SARS-CoV-2 entry, implicating its possible roles as virus reservoir and accelerator reinforcing violent systemic inflammation and immune response. Finally, anti-inflammatory cytokines like anti-interleukin 6 and administration of mesenchymal stromal/stem cells may serve as potential immune modulatory therapies for supportively combating COVID-19. Obesity is conversely related to the development of COVID-19 through numerous molecular mechanisms and individuals with obesity belong to the COVID-19-susceptible population requiring more protective measures.

Obesity-Driven Deficiencies of Specialized Pro-resolving Mediators May Drive Adverse Outcomes During SARS-CoV-2 Infection

Obesity is a major independent risk factor for increased morbidity and mortality upon infection with Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2), which is responsible for the current coronavirus disease pandemic (COVID-19). Therefore, there is a critical need to identify underlying metabolic factors associated with obesity that could be contributing toward increased susceptibility to SARS-CoV-2 in this vulnerable population. Here, we focus on the critical role of potent endogenous lipid metabolites known as specialized pro-resolving mediators (SPMs) that are synthesized from polyunsaturated fatty acids. SPMs are generated during the transition of inflammation to resolution and have a vital role in directing damaged tissues to homeostasis; furthermore, SPMs display anti-viral activity in the context of influenza infection without being immunosuppressive. We cover evidence from rodent and human studies to show that obesity, and its co-morbidities, induce a signature of SPM deficiency across immunometabolic tissues. We further discuss how the effects of obesity upon SARS-CoV-2 infection are likely exacerbated with environmental exposures that promote chronic pulmonary inflammation and augment SPM deficits. Finally, we highlight potential approaches to overcome the loss of SPMs using dietary and pharmacological interventions. Collectively, this mini-review underscores the need for mechanistic studies on how SPM deficiencies driven by obesity and environmental exposures may exacerbate the response to SARS-CoV-2.

Emerging Human Coronavirus Infections (SARS, MERS, and COVID-19): Where They Are Leading Us

Coronavirus infections are responsible for mild, moderate, and severe infections in birds and mammals. These were first isolated in humans as causal microorganisms responsible for common cold. The 2002-2003 SARS epidemic caused by SARS-CoV and 2012 MERS epidemic (64 countries affected) caused by MERS-CoV showed their acute and fatal side. These two CoV infections killed thousands of patients infected worldwide. However, WHO has still reported the MERS case in December 2019 in middle-eastern country (Saudi Arabia), indicating the MERS epidemic has not ended completely yet. Although we have not yet understood completely these two CoV epidemics, a third most dangerous and severe CoV infection has been originated in the Wuhan city, Hubei district of China in December 2019. This CoV infection called COVID-19 or SARS-CoV2 infection has now spread to 210 countries and territories around the world. COVID-19 has now been declared a pandemic by the World Health Organization (WHO). It has infected more than 16.69 million people with more than 663,540 deaths across the world. Thus the current manuscript aims to describe all three (SARS, MERS, and COVID-19) in terms of their causal organisms (SARS-CoV, MERS-CoV, and SARS-CoV2), similarities and differences in their clinical symptoms, outcomes, immunology, and immunopathogenesis, and possible future therapeutic approaches.

Hypercoagulopathy and Adipose Tissue Exacerbated Inflammation May Explain Higher Mortality in COVID-19 Patients With Obesity

COVID-19, caused by SARS-CoV-2, is characterized by pneumonia, lymphopenia, exhausted lymphocytes and a cytokine storm. Several reports from around the world have identified obesity and severe obesity as one of the strongest risk factors for COVID-19 hospitalization and mechanical ventilation. Moreover, countries with greater obesity prevalence have a higher morbidity and mortality risk of developing serious outcomes from COVID-19. The understanding of how this increased susceptibility of the people with obesity to develop severe forms of the SARS-CoV-2 infection occurs is crucial for implementing appropriate public health and therapeutic strategies to avoid COVID-19 severe symptoms and complications in people living with obesity. We hypothesize here that increased ACE2 expression in adipose tissue displayed by people with obesity may increase SARS-CoV-2 infection and accessibility to this tissue. Individuals with obesity have increased white adipose tissue, which may act as a reservoir for a more extensive viral spread with increased shedding, immune activation and pro-inflammatory cytokine amplification. Here we discuss how obesity is related to a pro-inflammatory and metabolic dysregulation, increased SARS-CoV-2 host cell entry in adipose tissue and induction of hypercoagulopathy, leading people with obesity to develop severe forms of COVID-19 and also death. Taken together, it may be crucial to better explore the role of visceral adipose tissue in the inflammatory response to SARS-CoV-2 infection and investigate the potential therapeutic effect of using specific target anti-inflammatories (canakinumab or anakinra for IL-1β inhibition; anti-IL-6 antibodies for IL-6 inhibition), anticoagulant or anti-diabetic drugs in COVID-19 treatment of people with obesity. Defining the immunopathological changes in COVID-19 patients with obesity can provide prominent targets for drug discovery and clinical management improvement.