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Self-organized patchiness in asthma as a prelude to catastrophic shifts

Abstract

Asthma is a common disease affecting an increasing number of children throughout the world. In asthma, pulmonary airways narrow in response to contraction of surrounding smooth muscle. The precise nature of functional changes during an acute asthma attack is unclear. The tree structure of the pulmonary airways has been linked to complex behaviour in sudden airway narrowing1,2 and avalanche-like reopening3,4. Here we present experimental evidence that bronchoconstriction leads to patchiness in lung ventilation, as well as a computational model that provides interpretation of the experimental data. Using positron emission tomography, we observe that bronchoconstricted asthmatics develop regions of poorly ventilated lung. Using the computational model we show that, even for uniform smooth muscle activation of a symmetric bronchial tree, the presence of minimal heterogeneity breaks the symmetry and leads to large clusters of poorly ventilated lung units. These clusters are generated by interaction of short- and long-range feedback mechanisms, which lead to catastrophic shifts similar to those linked to self-organized patchiness in nature5,6. This work might have implications for the treatment of asthma, and might provide a model for studying diseases of other distributed organs.

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Figure 1: Heterogeneity in bronchoconstriction of an asthmatic's lung.
Figure 2: Modelling of bronchoconstricted lungs.
Figure 3: Tidal volume-dependent hysteresis in regional ventilation distribution to terminal units.
Figure 4: Distributions of ventilation under three conditions.

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References

  1. Suki, B. & Frey, U. Temporal dynamics of recurrent airway symptoms and cellular random walk. J. Appl. Physiol. 95, 2122–2127 (2003)

    Article  Google Scholar 

  2. Mauroy, B., Filoche, M., Weibel, E. R. & Sapoval, B. An optimal bronchial tree may be dangerous. Nature 427, 633–636 (2004)

    Article  ADS  CAS  Google Scholar 

  3. Suki, B., Barabasi, A. L., Hantos, Z., Petak, F. & Stanley, H. E. Avalanches and power-law behaviour in lung inflation. Nature 368, 615–618 (1994)

    Article  ADS  CAS  Google Scholar 

  4. Alencar, A. M. et al. Physiology: Dynamic instabilities in the inflating lung. Nature 417, 809–811 (2002)

    Article  ADS  CAS  Google Scholar 

  5. Judd, S. L. & Silber, M. Simple and superlattice Turing patterns in reaction-diffusion systems: bifurcation, bistability, and parameter collapse. Physica D. 136, 45–65 (2000)

    Article  ADS  MathSciNet  CAS  Google Scholar 

  6. Rietkerk, M., Dekker, S. C., de Ruiter, P. C. & van de Koppel, J. Self-organized patchiness and catastrophic shifts in ecosystems. Science 305, 1926–1929 (2004)

    Article  ADS  CAS  Google Scholar 

  7. Beigelman-Aubry, C. et al. Mild intermittent asthma: CT assessment of bronchial cross-sectional area and lung attenuation at controlled lung volume. Radiology 223, 181–187 (2002)

    Article  Google Scholar 

  8. Lutchen, K. R. et al. Airway constriction pattern is a central component of asthma severity: the role of deep inspirations. Am. J. Respir. Crit. Care Med. 164, 207–215 (2001)

    Article  CAS  Google Scholar 

  9. Samee, S. et al. Imaging the lungs in asthmatic patients by using hyperpolarized helium-3 magnetic resonance: assessment of response to methacholine and exercise challenge. J. Allergy Clin. Immunol. 111, 1205–1211 (2003)

    Article  CAS  Google Scholar 

  10. Klarreich, E. Take a deep breath. Nature 424, 873–874 (2003)

    Article  ADS  CAS  Google Scholar 

  11. Vidal Melo, M. F. et al. Quantification of regional ventilation-perfusion ratios with PET. J. Nucl. Med. 44, 1982–1991 (2003)

    PubMed  Google Scholar 

  12. Anafi, R. C., Beck, K. C. & Wilson, T. A. Impedance, gas mixing, and bimodal ventilation in constricted lungs. J. Appl. Physiol. 94, 1003–1011 (2003)

    Article  Google Scholar 

  13. Anafi, R. C. & Wilson, T. A. Airway stability and heterogeneity in the constricted lung. J. Appl. Physiol. 91, 1185–1192 (2001)

    Article  CAS  Google Scholar 

  14. Lauwerier, H. Fractals: Endlessly Repeated Geometric Figures 71–73 (Princeton Univ. Press, Princeton, 1991)

    MATH  Google Scholar 

  15. Venegas, J. G. & Galletti, G. G. Low-pass filtering, a new method of fractal analysis: application to PET images of pulmonary blood flow. J. Appl. Physiol. 88, 1365–1373 (2000)

    Article  CAS  Google Scholar 

  16. Altemeier, W. A., McKinney, S. & Glenny, R. W. Fractal nature of regional ventilation distribution. J. Appl. Physiol. 88, 1551–1557 (2000)

    Article  CAS  Google Scholar 

  17. Fredberg, J. J. Bronchospasm and its biophysical basis in airway smooth muscle. Respir. Res. 5, 2 (2004)

    Article  Google Scholar 

  18. Latourelle, J., Fabry, B. & Fredberg, J. J. Dynamic equilibration of airway smooth muscle contraction during physiological loading. J. Appl. Physiol. 92, 771–779 (2002)

    Article  Google Scholar 

  19. Skloot, G., Permutt, S. & Togias, A. Airway hyperresponsiveness in asthma: a problem of limited smooth muscle relaxation with inspiration. J. Clin. Invest. 96, 2393–2403 (1995)

    Article  CAS  Google Scholar 

  20. Bates, J. H. Bronchoconstriction and broken symmetry. Comments Theor. Biol. 3, 397–415 (1995)

    Google Scholar 

  21. Wagers, S. Polarized helium: changing our view of asthma. J. Allergy Clin. Immunol. 111, 1201–1202 (2003)

    Article  Google Scholar 

  22. Laurent, F., Latrabe, V., Raherison, C., Marthan, R. & Tunon-de-Lara, J. M. Functional significance of air trapping detected in moderate asthma. Eur. Radiol. 10, 1404–1410 (2000)

    Article  CAS  Google Scholar 

  23. Newman, K. B., Lynch, D. A., Newman, L. S., Ellegood, D. & Newell, J. D. Jr Quantitative computed tomography detects air trapping due to asthma. Chest 106, 105–109 (1994)

    Article  CAS  Google Scholar 

  24. Cox, P. G., Miller, J., Mitzner, W. & Leff, A. R. Radiofrequency ablation of airway smooth muscle for sustained treatment of asthma: preliminary investigations. Eur. Respir. J. 24, 659–663 (2004)

    Article  CAS  Google Scholar 

  25. Danek, C. J. et al. Reduction in airway hyperresponsiveness to methacholine by the application of RF energy in dogs. J. Appl. Physiol. 97, 1946–1953 (2004)

    Article  CAS  Google Scholar 

  26. Smith, D. et al. Intravenous epinephrine in life-threatening asthma. Ann. Emerg. Med. 41, 706–711 (2003)

    Article  Google Scholar 

  27. Musch, G. et al. Topographical distribution of pulmonary perfusion and ventilation, assessed by PET in supine and prone humans. J. Appl. Physiol. 93, 1841–1851 (2002)

    Article  Google Scholar 

  28. Weibel, E. R. Morphometry of the Human Lung 115–126 (Berlin, Springer, 1963)

    Book  Google Scholar 

  29. Smith, J. C., Butler, J. P. & Hoppin, F. G. Jr Contribution of tree structures in the lung to lung elastic recoil. J. Appl. Physiol. 57, 1422–1429 (1984)

    Article  CAS  Google Scholar 

  30. Gunst, S. J. & Stropp, J. Q. Pressure-volume and length-stress relationships in canine bronchi in vitro . J. Appl. Physiol. 64, 2522–2531 (1988)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We are grateful to T. A. Wilson, K. M. Miller, E. Lowenstein, B. Suki, J. P. Butler, M. Reitkerk and J. J. Fredberg for their suggestions and comments during the preparation of the manuscript. J. A. Correia and W. M. Bucelewicz are thanked for their help with technical aspects of the tracer preparation. This work was funded by an NIH HLBI grant.Authors' contributions J.G.V. and T.W. contributed equally to the theoretical aspects of this work. All authors contributed to experimental components of this work.

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Correspondence to Jose G. Venegas.

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The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Methods S1

Details of PET imaging of Bronchoconstriction and the Model of Bronchoconstriction in an Airway Tree (PDF 134 kb)

Supplementary Video Legends S2

Legends to accompany the below Supplementary Videos. (PDF 46 kb)

Supplementary Video S3

Regional kinetics of the 13NN tracer in an asthmatic subject at baseline illustrates an almost complete removal of the tracer by the end of a washout period. (MPG 687 kb)

Supplementary Video S4

Regional kinetics of the 13NN tracer in an asthmatic subject during bronchoconstriction shows a substantially reduced washout from large contiguous 'ventilation defects'. (MPG 645 kb)

Supplementary Figure S5

Full set of PET images from an asthmatic subject during bronchoconstriction showing the residual tracer before and after deep inspiration. (PDF 317 kb)

Supplementary Video S6

Spatial distribution and histogram of terminal unit ventilation in the network model during a slow steady increase in smooth muscle relative activation from 0 to 1. (MPG 5997 kb)

Supplementary Figure S7

Complex dynamics of ventilation within the model during the simulation as a function of smooth muscle activation level. (PDF 611 kb)

Supplementary Figure S8

Fraction of clusters size and fraction of severely obstructed units as a function of tidal volume. (PDF 56 kb)

Supplementary Figure S9

Airway radius, normalized by the corresponding radius in relaxed conditions, versus generation number for each of the model's 12 generations. (PDF 334 kb)

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Venegas, J., Winkler, T., Musch, G. et al. Self-organized patchiness in asthma as a prelude to catastrophic shifts. Nature 434, 777–782 (2005). https://doi.org/10.1038/nature03490

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