Dataset Information

A multiscale, spatially distributed model of asthmatic airway hyper-responsiveness.

ABSTRACT: We present a multiscale, spatially distributed model of lung and airway behaviour with the goal of furthering the understanding of airway hyper-responsiveness and asthma. The model provides an initial computational framework for linking events at the cellular and molecular levels, such as Ca(2+) and crossbridge dynamics, to events at the level of the entire organ. At the organ level, parenchymal tissue is modelled using a continuum approach as a compressible, hyperelastic material in three dimensions, with expansion and recoil of lung tissue due to tidal breathing. The governing equations of finite elasticity deformation are solved using a finite element method. The airway tree is embedded in this tissue, where each airway is modelled with its own airway wall, smooth muscle and surrounding parenchyma. The tissue model is then linked to models of the crossbridge mechanics and their control by Ca(2+) dynamics, thus providing a link to molecular and cellular mechanisms in airway smooth muscle cells. By incorporating and coupling the models at these scales, we obtain a detailed, computational multiscale model incorporating important physiological phenomena associated with asthma.

SUBMITTER: Politi AZ

PROVIDER: S-EPMC2939299 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A multiscale, spatially distributed model of asthmatic airway hyper-responsiveness.

Politi Antonio Z AZ Donovan Graham M GM Tawhai Merryn H MH Sanderson Michael J MJ Lauzon Anne-Marie AM Bates Jason H T JH Sneyd James J

Journal of theoretical biology 20100804 4

We present a multiscale, spatially distributed model of lung and airway behaviour with the goal of furthering the understanding of airway hyper-responsiveness and asthma. The model provides an initial computational framework for linking events at the cellular and molecular levels, such as Ca(2+) and crossbridge dynamics, to events at the level of the entire organ. At the organ level, parenchymal tissue is modelled using a continuum approach as a compressible, hyperelastic material in three dimen ...[more]

PMID: 20678506

Similar Datasets

Project description:BackgroundAlthough ambient air pollution has been linked to reduced lung function in healthy children, longitudinal analyses of pollution effects in asthmatic patients are lacking.ObjectiveWe sought to investigate pollution effects in a longitudinal asthma study and effect modification by controller medications.MethodsWe examined associations of lung function and methacholine responsiveness (PC20) with ozone, carbon monoxide (CO), nitrogen dioxide, and sulfur dioxide concentrations in 1003 asthmatic children participating in a 4-year clinical trial. We further investigated whether budesonide and nedocromil modified pollution effects. Daily pollutant concentrations were linked to ZIP/postal code of residence. Linear mixed models tested associations of within-subject pollutant concentrations with FEV1 and forced vital capacity (FVC) percent predicted, FEV1/FVC ratio, and PC20, adjusting for seasonality and confounders.ResultsSame-day and 1-week average CO concentrations were negatively associated with postbronchodilator percent predicted FEV1 (change per interquartile range, -0.33 [95% CI, -0.49 to -0.16] and -0.41 [95% CI, -0.62 to -0.21], respectively) and FVC (-0.19 [95% CI, -0.25 to -0.07] and -0.25 [95% CI, -0.43 to -0.07], respectively). Longer-term 4-month CO averages were negatively associated with prebronchodilator percent predicted FEV1 and FVC (-0.36 [95% CI, -0.62 to -0.10] and -0.21 [95% CI, -0.42 to -0.01], respectively). Four-month averaged CO and ozone concentrations were negatively associated with FEV1/FVC ratio (P < .05). Increased 4-month average nitrogen dioxide concentrations were associated with reduced postbronchodilator FEV1 and FVC percent predicted. Long-term exposures to sulfur dioxide were associated with reduced PC20 (percent change per interquartile range, -6% [95% CI, -11% to -1.5%]). Treatment augmented the negative short-term CO effect on PC20.ConclusionsAir pollution adversely influences lung function and PC20 in asthmatic children. Treatment with controller medications might not protect but rather worsens the effects of CO on PC20. This clinical trial design evaluates modification of pollution effects by treatment without confounding by indication.

Project description:IntroductionCeramide is the central substrate of sphingolipid metabolism and plays a key role in cellular signal transduction pathways, regulating apoptosis, differentiation, and chemotaxis. Alterations in airway ceramide levels are observed in multiple pulmonary diseases and recent human genetic association studies have linked dysregulation of sphingolipid regulatory genes with asthma pathogenesis.MethodsUtilizing myriocin, a potent inhibitor of sphingolipid synthesis, we evaluated the immune regulatory role of de novo ceramide generation in vitro and in vivo. Intratracheal myriocin was administered alone or during house dust mite sensitization (HDM) of BALB/C mice and airway hyper-responsiveness (AHR) was evaluated by invasive plethysmography followed by bronchial lavage (BAL) cytology and cytokine quantification.ResultsMyriocin inhibits and HDM exposure activates de novo ceramide synthesis in bone marrow-derived dendritic cells. Mice receiving intratracheal myriocin developed a mild airway neutrophilic infiltrate without inducing a significant increase in AHR. CXCL1 was elevated in the BAL fluid of myriocin-treated mice while the neutrophilic chemotactic factors anaphylatoxin C5a, leukotriene B4, and IL-17 were unaffected. HDM treatment combined with myriocin led to a dramatic enhancement of AHR (63% increase over HDM alone, p < 0.001) and increased granulocyte pulmonary infiltrates versus HDM or myriocin alone. Elevated Th2 T cell counts and Th2 cytokines/chemokines (IL5, IL13, CCL17) were observed in mice treated with combined HDM/myriocin compared to HDM alone. Myriocin-treated pulmonary CD11c+ cells stimulated with HDM secreted significantly more CXCL1 than cells stimulated with HDM alone while HDM stimulated airway epithelial cells showed no change in CXCL1 secretion following myriocin treatment.ConclusionsIntratracheal myriocin, likely acting via ceramide synthesis inhibition, enhances allergen-induced airway inflammation, granulocyte and Th2 lymphocyte recruitment, and allergen-induced AHR. Sphingolipid pathways may represent novel targets for possible future anti-inflammatory asthma medications.

Project description:Selective stimulation of IL-4 receptor on smooth muscle induces airway hyper-responsiveness in mice. Abstract: Production of the cytokines IL-4 and IL-13 is increased in both human asthma and mouse asthma models and Stat6 activation by the common IL-4/IL-13R drives most mouse model pathophysiology, including airway hyperresponsiveness (AHR). However, the precise cellular mechanisms through which IL-4Rα induces AHR remain unclear. Overzealous bronchial smooth muscle constriction is thought to underlie AHR in human asthma, but the smooth muscle contribution to AHR has never been directly assessed. Furthermore, differences in mouse vs. human airway anatomy and observations that selective IL-13 stimulation of Stat6 in airway epithelium induces murine AHR raise questions about the importance of direct IL-4R effects on smooth muscle in murine asthma models and relevance of these models to human asthma. Using transgenic mice in which smooth muscle is the only cell type that expresses or fails to express IL-4Rα, we demonstrate that direct smooth muscle activation by IL-4, IL-13, or allergen is sufficient, but not necessary, to induce AHR and show that 5 genes known to promote smooth muscle migration, proliferation and contractility are activated by IL-13 in smooth muscle in vivo. These observations demonstrate that IL-4Rα promotes AHR through multiple mechanisms and provide a model for testing smooth muscle-directed asthma therapeutics. For the microarray aspect of of the study, there were three groups of mice: 1. IL4R gene knockout (KO) mice 2. WT mice 3. IL4R KO mice that were also transgenic for a gene construct that expressed IL4R under the control of the smooth muscle-specific promoter from the SMP8 gene All mice were subjected to intratracheal IL13 exposure for 7 days, and whole lung RNA was prepared for microarray analysis 24 hours after the last instillation. Per treatment and genotype: Two RNA pools were made from four mice each. These were labeled and hybridized to make a total of 6 microarrays. RNA was labeled with the standard Affymetrix 3' labeling protocol to make cDNA that was hybridized to Mouse MOE 430 plus 2.0 GeneChips. Gene transcripts were identified that differed in their relative expression as a function of IL4R expression on the smooth muscle cells.

Dataset Information

A multiscale, spatially distributed model of asthmatic airway hyper-responsiveness.

Publications

A multiscale, spatially distributed model of asthmatic airway hyper-responsiveness.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets