Browsing by Author "Ihrie, Mark D"

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Exogenous leptin enhances markers of airway fibrosis in a mouse model of chronic allergic airways disease.
    (Respiratory research, 2022-05-24) Ihrie, Mark D; McQuade, Victoria L; Womble, Jack T; Hegde, Akhil; McCravy, Matthew S; Lacuesta, Cyrus Victor G; Tighe, Robert M; Que, Loretta G; Walker, Julia KL; Ingram, Jennifer L

    Background

    Asthma patients with comorbid obesity exhibit increased disease severity, in part, due to airway remodeling, which is also observed in mouse models of asthma and obesity. A mediator of remodeling that is increased in obesity is leptin. We hypothesized that in a mouse model of allergic airways disease, mice receiving exogenous leptin would display increased airway inflammation and fibrosis.

    Methods

    Five-week-old male and female C57BL/6J mice were challenged with intranasal house dust mite (HDM) allergen or saline 5 days per week for 6 weeks (n = 6-9 per sex, per group). Following each HDM exposure, mice received subcutaneous recombinant human leptin or saline. At 48 h after the final HDM challenge, lung mechanics were evaluated and the mice were sacrificed. Bronchoalveolar lavage was performed and differential cell counts were determined. Lung tissue was stained with Masson's trichrome, periodic acid-Schiff, and hematoxylin and eosin stains. Mouse lung fibroblasts were cultured, and whole lung mRNA was isolated.

    Results

    Leptin did not affect mouse body weight, but HDM+leptin increased baseline blood glucose. In mixed-sex groups, leptin increased mouse lung fibroblast invasiveness and increased lung Col1a1 mRNA expression. Total lung resistance and tissue damping were increased with HDM+leptin treatment, but not leptin or HDM alone. Female mice exhibited enhanced airway responsiveness to methacholine with HDM+leptin treatment, while leptin alone decreased total respiratory system resistance in male mice.

    Conclusions

    In HDM-induced allergic airways disease, administration of exogenous leptin to mice enhanced lung resistance and increased markers of fibrosis, with differing effects between males and females.
  • Thumbnail Image
    ItemOpen Access
    Imbalanced Coagulation in the Airway of Type-2 High Asthma with Comorbid Obesity.
    (Journal of asthma and allergy, 2021-01) Womble, Jack T; McQuade, Victoria L; Ihrie, Mark D; Ingram, Jennifer L
    Asthma is a common, chronic airway inflammatory disease marked by airway hyperresponsiveness, inflammation, and remodeling. Asthma incidence has increased rapidly in the past few decades and recent multicenter analyses have revealed several unique asthma endotypes. Of these, type-2 high asthma with comorbid obesity presents a unique clinical challenge marked by increased resistance to standard therapies and exacerbated disease development. The extrinsic coagulation pathway plays a significant role in both type-2 high asthma and obesity. The type-2 high asthma airway is marked by increased procoagulant potential, which is readily activated following damage to airway tissue. In this review, we summarize the current understanding of the role the extrinsic coagulation pathway plays in the airway of type-2 high asthma with comorbid obesity. We propose that asthma control is worsened in obesity as a result of a systemic and local airway shift towards a procoagulant and anti-fibrinolytic environment. Lastly, we hypothesize bariatric surgery as a treatment for improved asthma management in type-2 high asthma with comorbid obesity, facilitated by normalization of systemic procoagulant and pro-inflammatory mediators. A better understanding of attenuated coagulation parameters in the airway following bariatric surgery will advance our knowledge of biomolecular pathways driving asthma pathobiology in patients with obesity.
  • Thumbnail Image
    ItemOpen Access
    Orchestrating Airway Smooth Muscle Cell Migration: GMFγ Phosphorylation Is the Key.
    (American journal of respiratory cell and molecular biology, 2019-08) Ihrie, Mark D; Ingram, Jennifer L
  • Thumbnail Image
    ItemOpen Access
    Vertical sleeve gastrectomy associates with airway hyperresponsiveness in a murine model of allergic airway disease and obesity.
    (Frontiers in endocrinology, 2023-01) Womble, Jack T; Ihrie, Mark D; McQuade, Victoria L; Hegde, Akhil; McCravy, Matthew S; Phatak, Sanat; Tighe, Robert M; Que, Loretta G; D'Alessio, David; Walker, Julia KL; Ingram, Jennifer L

    Introduction

    Asthma is a chronic airway inflammatory disease marked by airway inflammation, remodeling and hyperresponsiveness to allergens. Allergic asthma is normally well controlled through the use of beta-2-adrenergic agonists and inhaled corticosteroids; however, a subset of patients with comorbid obesity experience resistance to currently available therapeutics. Patients with asthma and comorbid obesity are also at a greater risk for severe disease, contributing to increased risk of hospitalization. Bariatric surgery improves asthma control and airway hyperresponsiveness in patients with asthma and comorbid obesity, however, the underlying mechanisms for these improvements remain to be elucidated. We hypothesized that vertical sleeve gastrectomy (VSG), a model of metabolic surgery in mice, would improve glucose tolerance and airway inflammation, resistance, and fibrosis induced by chronic allergen challenge and obesity.

    Methods

    Male C57BL/6J mice were fed a high fat diet (HFD) for 13 weeks with intermittent house dust mite (HDM) allergen administration to induce allergic asthma, or saline as control. At week 11, a subset of mice underwent VSG or Sham surgery with one week recovery. A separate group of mice did not undergo surgery. Mice were then challenged with HDM or saline along with concurrent HFD feeding for 1-1.5 weeks before measurement of lung mechanics and harvesting of tissues, both of which occurred 24 hours after the final HDM challenge. Systemic and pulmonary cytokine profiles, lung histology and gene expression were analyzed.

    Results

    High fat diet contributed to increased body weight, serum leptin levels and development of glucose intolerance for both HDM and saline treatment groups. When compared to saline-treated mice, HDM-challenged mice exhibited greater weight gain. VSG improved glucose tolerance in both saline and HDM-challenged mice. HDM-challenged VSG mice exhibited an increase in airway hyperresponsiveness to methacholine when compared to the non-surgery group.

    Discussion

    The data presented here indicate increased airway hyperresponsiveness in allergic mice undergoing bariatric surgery.