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Published on: June 12, 2021

Phagocytosis of ultrasound contrast agent microbubbles by Kupffer cells

Kyosuke Yanagisawa1, Fuminori Moriyasu, Takeo Miyahara

  • 1Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.

Ultrasound in Medicine & Biology
|January 9, 2007
PubMed

Insights

Kupffer cells, the liver's macrophages, engulf ultrasound contrast agent microbubbles. This phagocytosis is responsible for the delayed parenchymal liver images seen in contrast-enhanced ultrasound.

Area of Science:

  • Hepatology
  • Radiology
  • Immunology

Background:

  • Delayed parenchymal phase liver images in ultrasound contrast imaging are linked to macrophage phagocytosis of microbubbles.
  • The specific role of liver-resident macrophages (Kupffer cells) in this process remains to be fully elucidated.

Purpose of the Study:

  • To investigate whether Kupffer cells phagocytose ultrasound contrast agents.
  • To determine if Kupffer cell elimination impacts delayed liver parenchymal phase imaging.

Main Methods:

  • In vitro phase-contrast microscopy to observe Kupffer cell phagocytosis of various ultrasound contrast agents.
  • In vivo Kupffer cell depletion using gadolinium chloride (GdCl(3)).
  • Assessment of delayed liver parenchymal phase imaging intensity following contrast agent administration in control and Kupffer cell-depleted mice.

Main Results:

  • Kupffer cells demonstrated in vitro phagocytosis of Sonazoid, Optison, Levovist, and SonoVue, with varying efficiencies (99% for Sonazoid/Optison, 47% for Levovist, 7.3% for SonoVue).
  • In vivo Kupffer cell elimination led to reduced delayed parenchymal image intensity with Sonazoid and Levovist.
  • No significant changes in delayed imaging were observed with SonoVue after Kupffer cell depletion.

Conclusions:

  • Kupffer cells actively phagocytose ultrasound contrast agents.
  • Kupffer cell phagocytosis is a key mechanism responsible for the delayed parenchymal phase liver images in contrast-enhanced ultrasound.
  • The degree of Kupffer cell involvement varies depending on the specific ultrasound contrast agent used.

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