Impact of obesity in asthma: Possible future therapies

Functional insights into PTGS2 rs689466 polymorphism associated to asthma in West Bengal, India

BACKGROUND

Asthma is characterized by bronchoconstriction and airway hyperresponsiveness. Interplay of environmental and genetic factors led to significant rise in asthma prevalence in India during past decades.

OBJECTIVE

This study investigated functional insights of prostaglandin-endoperoxide synthase 2 (PTGS2) rs689466 polymorphism among 155 pollen-induced patients and 155 controls in West Bengal population, India.

METHODS

Genotyping was performed using Polymerase chain reaction-Restriction fragment length polymorphism. Transcription Factors (TFs) for promoter region corresponding to the polymorphism location were searched by SNP2TFBS. DNA structures were docked with TFs in HDOCK. Protein-DNA interface was analysed by DNAproDB. Relative abundance of PTGS2 mRNA in controls and different polymorphic genotypes was obtained using Real time PCR. Protein expression was analyzed by western blot.

RESULTS

Genotype and allele frequencies differed significantly between study groups (P = 0.01 and 0.03 respectively). Frequency of GG and AG genotype was significantly higher in patients (P = 0.02 and 0.04 respectively). Significant differences in FEV1/FVC were obtained in different polymorphic genotypes of patients (P < 0.0001) whereas no difference was found in controls (P = 0.08). It was predicted PTGS2 expression decreased due to altered interactions between DNA and TFs in promoter region harbouring the polymorphism. PTGS2 mRNA expression was upregulated in patients bearing AA genotype whereas downregulated in patients with AG and GG genotypes. Protein expression was reduced in AG and GG carrying patients compared to patients bearing AA genotype.

CONCLUSION

This study is the first one to report association of PTGS2 rs689466 polymorphism in Indian population. This will help in gene-based therapy for improved asthma management in future.

Obesity-driven airway eosinophilia and neutrophilia in asthma

OBJECTIVE

Asthma patients with comorbid obesity tend to have more severe, difficult-to-control asthma than lean asthma patients. This increase in asthma severity may be due, in part, to obesity-related adipokines, such as leptin, which contribute to airway hyperresponsiveness, sustained subclinical chronic inflammation, and treatment resistance. This narrative literature review aims to elucidate the differences in airway eosinophilia and neutrophilia profiles between asthma patients with and without obesity.

METHODS

A PubMed search of full journal articles published between 1992 and 2024 was performed in April 2024 using the terms "asthma", "tissue eosinophilia" and "obesity" combined with the Boolean operator "AND". Articles detailing airway tissue eosinophilia and neutrophilia in asthma patients or mice were included. Only articles in English were included.

RESULTS

To date, several studies have reported increased airway tissue eosinophilia in obese mouse asthma models (four studies) and in asthma patients with obesity (three studies). Airway tissue eosinophilia in asthma patients with obesity is driven by altered and elevated levels of adipokines, pro-inflammatory cytokines, and eosinophil-stimulating chemokines such as eotaxin. Leptin and eotaxin levels are increased in asthma with obesity and contribute to enhanced eosinophil recruitment, migration, adhesion to airway smooth muscles and fibroblasts, and reduced apoptosis.

CONCLUSIONS

Airway tissue eosinophilia is an important feature of obesity-associated asthma. Airway tissue eosinophilia is mainly driven by obesity-related homeostatic changes. These increased airway tissue eosinophils contribute to a more severe disease.

The role of periostin, eosinophil cationic protein (ECP), nesfatin-1, and NUCB2 in asthma and obesity

BACKGROUND

Obesity has a significant impact on asthma incidence and control. Nesfatin-1, encoded by the nucleobindin-2 (NUCB2) gene, regulates energy balance. This study aimed to evaluate NUCB2 gene polymorphism (rs757081 C > G) and its association with serum levels of nesfatin-1 and inflammatory cytokines in obese and non-obese patients with asthma.

METHODS

Obese (n = 43) and non-obese (n = 44) patients diagnosed with asthma and 45 control subjects were included. Nesfatin-1, eosinophil cationic protein (ECP), and periostin were studied in serum samples using the ELISA method. NUCB2 polymorphism was studied by PCR method.

RESULTS

No difference was found between groups regarding NUCB2 polymorphism (CC, CG, GG) (p = 0.497). Nesfatin-1 levels were higher in the obese asthmatics than in the control (median 1.69 ng/ml vs 1.36 ng/ml, p = 0.004). ECP levels were higher in the obese asthmatics (median 7.67 ng/ml) compared to non-obese asthmatic (median 1.98 ng/ml) and control (median 1.45 ng/ml) (p < 0.001, p < 0.001 respectively). Periostin was found to be lower in both obese (median 0.34 ng/ml) and non-obese asthmatics (median 0.35 ng/ml) compared to control (median 1.2 ng/ml) (p = 0.001, p < 0.001, respectively). There was a positive correlation between BMI and nesfatin-1 (r = 0.33, p < 0.001) and ECP (r = 0.58, p < 0.001). In regression analysis, ECP (95% CI: 0.19 to 0.75, p = 0.005) and periostin (95% CI: 4.5 to 375.1, p = 0.003) were independent predictors for asthma.

CONCLUSION

Nesfatin-1 and ECP have been shown to be increased in obese asthmatics. ECP and periostin have been identified as a predictor of asthma independent of obesity.

Obesity: Next game changer of allergic airway diseases?

Obesity and allergic diseases are global health concerns, both of which are seeing an increase in prevalence in recent years. Obesity has been recognised as an important comorbidity in subpopulations with allergic airway diseases, which represents a unique phenotype and endotype. Obesity-related allergic airway diseases are associated with exacerbated clinical symptom burden, altered immune response, increased disease severity and compromised predictive capability of conventional biomarkers for evaluating endotype and prognosis. Moreover, treatment of obesity-related allergic airway diseases is challenging because this unique endotype and phenotype is associated with poor response to standard therapeutic strategies. Therapeutic regimen that involves weight loss by non-surgical and surgical interventions, gut microbiome-targeted treatment, glucagon-like peptide-1 receptor agonist and other agents should be considered in this population. In this review, we outline the current knowledge of the impact of obesity on prevalence, endotypes, clinical symptom and management of allergic airway diseases. Increased understanding of the implications of obesity may contribute to better treatment options for the obesity-related refractory airway inflammation, particularly in precision medicine. KEY POINTS: Obesity can increase the prevalence of allergic airway diseases such as asthma, AR, and CRSwNP. Obesity alters the immune endotype and exacerbates clinical symptoms of respiratory allergic diseases. Obesity-related allergic airway diseases exhibit therapeutic resistance to standard treatment. Obesity-related allergic airway diseases constitute a distinct category of endotypes and phenotypes, requiring further in-depth research and novel therapeutic approaches.

Food for thought: optimal diet in patients with asthma and chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Nutritional intake plays a major role in the management of lung health. This review provides the latest perspective on how dietary choices can modulate lung function in patients with chronic obstructive pulmonary disease (COPD) and asthma.

RECENT FINDINGS

The pathophysiology of COPD and asthma is driven by oxidative stress and inflammation of the airways, which is exacerbated by modifiable risk factors such as cigarette smoking and diet. Various foods can influence patient symptoms; highly processed foods increase the production of reactive oxygen species that augment airway inflammation, whereas foods rich in antioxidants, fiber and protein combat oxidative stress and muscle wastage. Patients with COPD or asthma are at increased risk of developing metabolic comorbidities, including cachexia and obesity that complicate disease phenotypes, leading to greater symptom severity. While clinical findings suggest a role for antioxidant and macronutrient support of lung function, comprehensive translational and clinical studies are necessary to better understand the mechanisms underlying nutrient interaction and lung structure-function.

SUMMARY

Understanding the nutritional requirements that protect lung health and support weight management in COPD and asthma is imperative to providing personalized dietary recommendations and reducing patient morbidity.

Molecular mechanisms and clinical impact of biologic therapies in severe asthma

Severe asthma is a critical condition for patients with asthma, characterized by frequent exacerbations, decreased pulmonary function, and unstable symptoms related to asthma. Consequently, the administration of systemic corticosteroids, which cause secondary damage because of their adverse effects, is considered. Recently, several types of molecular-targeted biological therapies have become available for patients with severe asthma, and they have a capacity to improve the pathophysiology of severe asthma. However, several clinical reports indicate that the effects differ depending on the biological targets of asthma in individual patients. In this review, the molecular mechanisms and clinical impact of biologic therapies in severe asthma are described. In addition, molecules targeted by possible future biologics are also addressed. Better understanding of the mechanistic basis for the role of biologics in severe asthma could lead to new therapeutic options for these patients.

Polypharmacy in older patients with asthma: hidden risks and opportunities for improvement

INTRODUCTION

Polypharmacy can be considered the norm in elderly patients, because older individuals experience an increasing number of concomitant respiratory and non-respiratory diseases other than asthma, carrying the risk of drug-to-drug-interactions and drug-to-comorbidities interactions. In this context, asthma in older adults, conventionally aging >65 years of age, cannot be adequately managed without considering their individual characteristics, as these challenge the traditional therapeutic algorithms/management strategies commonly applied to younger populations.

AREAS COVERED

The current article aims at addressing pitfalls and advantages of current pharmacological strategies in older individuals with asthma. Comorbidities become more common with increasing age and are also more frequent in adults with asthma than in those without it. Multiple medications are often needed to control asthma symptoms and prevent asthma exacerbations, and older patients with asthma may also take multiple medications for common comorbidities and complex health conditions, such as chronic cardiometabolic diseases. Polypharmacy is an emerging concern in the elderly population.

EXPERT OPINION

A patient-centered approach is crucial and polypharmacy in asthma requires careful management. A multidisciplinary approach will allow for a more holistic care and will ensure that all aspects of a patient's health are considered, optimizing medication management.

Association between advanced lung cancer inflammation index and unstable asthma: a population-based study from the NHANES 2007-2018

Background

Asthma exacerbation is associated with obesity and systemic inflammatory diseases, and advanced lung cancer inflammation index (ALI) is a novel biomarker of nutritional inflammation. The purpose of this study was to investigate the potential relationship between ALI and unstable asthma.

Methods

This cross-sectional study utilized data from the 2007-2018 National Health and Nutrition Examination Survey (NHANES). Asthma was assessed through self-reported questionnaires. Multifactorial logistic regression, subgroup analyses, interaction assessments, smoothed curve fitting, and threshold effect analysis models were conducted to investigate the association between ALI and unstable asthma.

Results

The study included 1,822 subjects with current asthma, and we found a linear positive association between ALI and unstable asthma, with higher levels of ALI significantly associated with an increased risk of asthma exacerbations in fully corrected models. However, the associations were not entirely consistent across subgroups. In subgroup analyses by body mass index (BMI) and race, unstable asthma and ALI were independently significant in the BMI (25-29.9) range and the Non-Hispanic White group. Interaction analysis suggested that BMI moderated the relationship between ALI and unstable asthma. Furthermore, smoothed curve fitting showed an inverted U-shaped relationship between log ALI and unstable asthma in subjects with a BMI <25 and male individuals, with inflection points observed at 1.53 and 2.13, respectively.

Conclusion

We found a linear positive association between ALI and unstable asthma, which remained constant in the fully adjusted model. These findings suggest that higher levels of ALI were significantly associated with an increased risk of asthma exacerbation, particularly in asthmatic populations with BMI in the 25-29.9 range. However, more prospective studies are required to confirm our findings.

A clinician's guide to effects of obesity on childhood asthma and into adulthood

INTRODUCTION

Obesity, one of the most common chronic conditions affecting the human race globally, affects several organ systems, including the respiratory system, where it contributes to onset and high burden of asthma. Childhood onset of obesity-related asthma is associated with high persistent morbidity into adulthood.

AREAS COVERED

In this review, we discuss the disease burden in children and adults to highlight the overlap between symptoms and pulmonary function deficits associated with obesity-related asthma in both age ranges, and then discuss the potential role of three distinct mechanisms, that of mechanical fat load, immune perturbations, and of metabolic perturbations on the disease burden. We also discuss interventions, including medical interventions for weight loss such as diet modification, that of antibiotics and anti-inflammatory therapies, as well as that of surgical intervention on amelioration of burden of obesity-related asthma.

EXPERT OPINION

With increase in obesity-related asthma due to increasing burden of obesity, it is evident that it is a disease entity distinct from asthma among lean individuals. The time is ripe to investigate the underlying mechanisms, focusing on identifying novel therapeutic targets as well as consideration to repurpose medications effective for other obesity-mediated complications, such as insulin resistance, dyslipidemia and systemic inflammation.

Impact of Overweight on Response to Dupilumab Treatment in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) significantly impacts quality of life and often presents therapeutic challenges, with biologics like dupilumab showing promise in managing severe, uncontrolled cases. The aim of this study was to assess the influence of overweight on the effectiveness of dupilumab in patients with uncontrolled CRSwNP. This retrospective study analyzed treatment outcomes of 75 CRSwNP patients receiving dupilumab, categorizing them into underweight/normal-weight (BMI ≤ 24.9 kg/m2) and overweight/obese (BMI ≥ 25 kg/m2) groups. Outcome measures included changes in nasal polyp score (NPS) and sinonasal outcome test (SNOT-22) scores. Results demonstrated that the underweight/normal-weight group experienced significantly greater improvements in NPS and a higher rate of total NPS improvement compared to the overweight/obese group. While SNOT-22 scores improved in both groups, no significant differences were observed. Among patients with comorbid asthma, the underweight/normal-weight subgroup also showed significantly better outcomes, including greater reductions in both NPS and SNOT-22 scores. Multiple regression analysis identified BMI as an independent prognostic factor for NPS outcomes. The findings suggest that overweight/obesity adversely affects the response to dupilumab in CRSwNP, emphasizing the need for personalized treatment strategies considering BMI.

Time-Restricted Eating Benefits on Pulmonary Function and Postural Balance in Overweight or Obese Women

This study aimed to evaluate the impact of time-restricted eating (TRE) on neuro-physiological parameters, objective and subjective sleep, pulmonary capacity, and postural balance among women with excess body weight.

METHODS

Thirty-one participants were assigned to either a TRE group (n = 15, 28.74 ± 9.25 years, 88.32 ± 13.38 kg, and 32.71 ± 5.15 kg/m2), engaging in ad libitum 16 h fasting over a 12-week period, or a control group (CG, n = 16, 36.25 ± 11.52 years, 90.88 ± 19.01 kg, and 33.66 ± 6.18 kg/m2). The assessment of heart rate variability (HRV), spirometric parameters (forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/ FVC ratio, objective and subjective sleep assessments employing actigraphy and the Epworth Sleepiness Scale, and postural balance using the Y balance test (YBT) were conducted before and after the intervention.

RESULTS

No significant negative effects of TRE were observed for HRV and objective sleep parameters. Only the TRE group improved FEV1 in both sitting (p < 0.0005) and supine positions (p = 0.001). Furthermore, the TRE group showed improvement in postural balance performance compared to the CG in anterior (p = 0.03), postero-medial (p = 0.04), and postero-lateral directions (p = 0.003).

CONCLUSION

This study highlights TRE as a feasible and safe dietary intervention with significant improvements in postural balance and pulmonary function, without any negative impact on HRV or objective sleep assessments among overweight or obese women.

Statin administration or blocking PCSK9 alleviates airway hyperresponsiveness and lung fibrosis in high-fat diet-induced obese mice

BACKGROUND

Obesity is associated with airway hyperresponsiveness and lung fibrosis, which may reduce the effectiveness of standard asthma treatment in individuals suffering from both conditions. Statins and proprotein convertase subtilisin/kexin-9 inhibitors not only reduce serum cholesterol, free fatty acids but also diminish renin-angiotensin system activity and exhibit anti-inflammatory effects. These mechanisms may play a role in mitigating lung pathologies associated with obesity.

METHODS

Male C57BL/6 mice were induced to develop obesity through high-fat diet for 16 weeks. Conditional TGF-β1 transgenic mice were fed a normal diet. These mice were given either atorvastatin or proprotein convertase subtilisin/kexin-9 inhibitor (alirocumab), and the impact on airway hyperresponsiveness and lung pathologies was assessed.

RESULTS

High-fat diet-induced obesity enhanced airway hyperresponsiveness, lung fibrosis, macrophages in bronchoalveolar lavage fluid, and pro-inflammatory mediators in the lung. These lipid-lowering agents attenuated airway hyperresponsiveness, macrophages in BALF, lung fibrosis, serum leptin, free fatty acids, TGF-β1, IL-1β, IL-6, and IL-17a in the lung. Furthermore, the increased RAS, NLRP3 inflammasome, and cholecystokinin in lung tissue of obese mice were reduced with statin or alirocumab. These agents also suppressed the pro-inflammatory immune responses and lung fibrosis in TGF-β1 over-expressed transgenic mice with normal diet.

CONCLUSIONS

Lipid-lowering treatment has the potential to alleviate obesity-induced airway hyperresponsiveness and lung fibrosis by inhibiting the NLRP3 inflammasome, RAS and cholecystokinin activity.

Associations of obesity with chronic inflammatory airway diseases and mortality in adults: a population-based investigation

BACKGROUND

The association between obesity and respiratory diseases has been confirmed. However, few studies have reported the relationship between obesity and the risk and mortality of chronic inflammatory airway disease (CIAD). The aim of this study was to reveal the association between obesity and the risk of CIAD, and mortality in patients with CIAD.

METHODS

The study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 2013 to 2018 among adults aged 20 years and above. All participants were grouped according to body mass index (BMI) and waist circumference (WC) levels to study the relationship between obesity and CIAD. Multivariate logistic regression analysis was utilized to examine the connection between CIAD and obesity in a cross-sectional study. The association between obesity and all-cause mortality in individuals with CIAD was examined using multiple cox regression models and smooth curve fitting in a prospective cohort study.

RESULTS

When stratified based on BMI in comparison to the normal weight group, the ORs with 95%CIs of CIAD for underweight and obesity were 1.39 (1.01-1.93) and 1.42 (1.27-1.58), respectively. The OR with 95%CI of CIAD for obesity was 1.20 (1.09-1.31) when stratified according to WC. Additionally, underweight was associated with a higher mortality (HR = 2.44, 95% CI = 1.31-4.55), whereas overweight (HR = 0.58,95% CI = 0.39-0.87) and obesity (HR = 0.59,95% CI = 0.4-0.87) were associated with a lower mortality (P for trend < 0.05). There was a non-linear association between BMI and all-cause mortality (P for non-linear = 0.001). An analysis of a segmentation regression model between BMI and all-cause mortality revealed a BMI turning point value of 32.4 kg/m2. The mortality of CIAD patients was lowest when BMI was 32.4 kg/m2. When BMI ≤ 32.4 kg/m2, BMI was inversely associated with all-cause mortality in patients with CIAD (HR: 0.92, 95%CI:0.88-0.97). However, when BMI > 32.4 kg/m2, there was no association between BMI and all-cause mortality (HR:1.02, 95%CI:0.97-1.06).

CONCLUSION

Compared to normal weight, underweight and obesity were associated with the increased risk of CIAD. Underweight was associated with increased all-cause mortality, while overweight was associated with reduced all-cause mortality. There was a non-linear association between BMI and all-cause mortality in patients with CIAD. The all-cause mortality was lowest when BMI was 32.4 kg/m2.

The Role of Peptides in Asthma-Obesity Phenotype

The co-occurrence of asthma and obesity is becoming an increasingly common health problem. It became clear that both diseases are closely related, since overweight/obesity are associated with an increased risk of asthma development, and more than half of the subjects with severe or difficult-to-treat asthma are obese. Currently, there are no specific guidelines for the treatment of this group of patients. The mechanisms involved in the asthma-obesity phenotype include low-grade chronic inflammation and changes in pulmonary physiology. However, genetic predispositions, gender differences, comorbid conditions, and gut microbiota also seem to be important. Regulatory peptides affect many processes related to the functioning of the respiratory tract and adipose tissue. Adipokines such as leptin, adiponectin, resistin, and the less studied omentin, chemerin, and visfatin, as well as the gastrointestinal hormones ghrelin, cholecystokinin, glucagon-like peptide-1, and neuropeptides, including substance P or neuropeptide Y, can play a significant role in asthma with obesity. The aim of this article is to provide a concise review of the contribution of particular peptides in inflammatory reactions, obesity, asthma, and a combination of both diseases, as well as emphasize their potential role in the effective treatment of the asthma-obesity phenotype in the future.