Real-time imaging reveals endothelium-mediated leukocyte retention in LPS-treated lung microvessels

Kathirvel Kandasamy, Geetaram Sahu, Kaushik Parthasarathi

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Endotoxemia, a major feature of sepsis, is a common cause of acute lung injury and initiates rapid accumulation of leukocytes in the lung vasculature. Endothelial mechanisms that underlie this accumulation remain unclear, as current experimental models of endotoxemia are less suitable for targeted activation of the endothelium. Toward elucidating this, we used the isolated blood-perfused rat lung preparation. With a microcatheter inserted through a left atrial cannula, we cleared blood cells from a small lung region and then infused lipopolysaccharide (LPS) into microvessels. After a Ringer's wash to remove residual LPS, we infused fluorescently-labeled autologous leukocytes and imaged their transit through the treated microvessels. Image analysis revealed that leukocytes infused 90. min after LPS treatment were retained more in treated venules and capillaries than untreated vessels. Further, pretreatment with either the intercellular adhesion molecule-1 (ICAM-1) mAb or polymyxin-B blunted LPS-induced leukocyte retention in both microvessel segments. In addition, retention of leukocytes treated ex vivo with LPS in LPS-treated microvessels was higher compared to retention of untreated leukocytes. In situ immunofluorescence experiments revealed that LPS significantly increased microvessel ICAM-1 expression at 90. min post treatment. Polymyxin pretreatment inhibited this increase. Taken together, the data suggest that LPS increased leukocyte retention in both venules and capillaries and this response was mediated by the increased expression of endothelial ICAM-1. Thus, endothelial mechanisms may themselves play a major role in LPS-induced leukocyte retention in lung microvessels. Blunting the endothelial responses may mitigate endotoxin-induced morbidity.

Original languageEnglish (US)
Pages (from-to)323-331
Number of pages9
JournalMicrovascular Research
Volume83
Issue number3
DOIs
StatePublished - May 1 2012

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Microvessels
Endothelium
Lipopolysaccharides
Leukocytes
Imaging techniques
Lung
Intercellular Adhesion Molecule-1
Endotoxemia
Venules
Blood
Polymyxins
Polymyxin B
Acute Lung Injury
Endotoxins
Image analysis
Fluorescent Antibody Technique
Rats
Blood Cells
Sepsis
Theoretical Models

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cardiology and Cardiovascular Medicine
  • Cell Biology

Cite this

Real-time imaging reveals endothelium-mediated leukocyte retention in LPS-treated lung microvessels. / Kandasamy, Kathirvel; Sahu, Geetaram; Parthasarathi, Kaushik.

In: Microvascular Research, Vol. 83, No. 3, 01.05.2012, p. 323-331.

Research output: Contribution to journalArticle

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