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Direct Observation of Phagocytosis and NET-formation by Neutrophils in Infected Lungs using 2-photon Microscopy
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Neutrophil retention during a single transit through the pulmonary circulation

J C Hogg1, C M Doerschuk, B Wiggs

  • 1Pulmonary Research Laboratory, University of British Columbia, Vancouver, Canada.

Journal of Applied Physiology (Bethesda, Md. : 1985)
|October 1, 1992
PubMed

Insights

Pulmonary circulation retains polymorphonuclear cells (PMNs) similarly to erythrocytes (RBCs) in both animals and humans. Gamma camera imaging previously underestimated PMN retention, but corrected analysis aligns findings across species.

Area of Science:

  • Pulmonary circulation
  • Hematology
  • Medical imaging techniques

Background:

  • Previous studies reported significant differences in polymorphonuclear cell (PMN) retention versus erythrocytes (RBCs) during lung passage between dogs (70-80% delay) and humans (5-15% delay).
  • These discrepancies may stem from the use of different methodologies: direct blood sampling in animals and gamma camera imaging in humans.

Purpose of the Study:

  • To reconcile the divergent findings on PMN retention in pulmonary circulation.
  • To determine if measurement technique, rather than species-specific physiology, accounts for observed differences in PMN vs. RBC transit through the lungs.

Main Methods:

  • A single species was used to directly compare direct blood sampling and gamma camera imaging techniques.
  • Data from gamma camera imaging were re-analyzed to assess the impact of analytical methods on PMN retention measurements.

Main Results:

  • The gamma camera technique, as previously applied to human studies, was found to underestimate PMN retention relative to RBCs in a single lung pass.
  • Modified analysis of gamma camera data demonstrated that the technique can accurately reflect PMN retention, comparable to direct sampling methods.
  • Corrected gamma camera analysis revealed similar degrees of PMN retention in pulmonary circulation for both species.

Conclusions:

  • The previously reported significant interspecies differences in PMN retention were largely an artifact of measurement technique.
  • Pulmonary circulation retains polymorphonuclear cells with respect to erythrocytes to a comparable extent in both animal models and humans.
  • Accurate analysis of gamma camera imaging data is crucial for reliable assessment of PMN transit through the lungs.

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