CCL2-dependent infiltrating macrophages promote angiogenesis in progressive liver fibrosis

Gut. 2014 Dec;63(12):1960-1971. doi: 10.1136/gutjnl-2013-306294. Epub 2014 Feb 21.


Objectives: In chronic liver injury, angiogenesis, the formation of new blood vessels from pre-existing ones, may contribute to progressive hepatic fibrosis and to development of hepatocellular carcinoma. Although hypoxia-induced expression of vascular endothelial growth factor (VEGF) occurs in advanced fibrosis, we hypothesised that inflammation may endorse hepatic angiogenesis already at early stages of fibrosis.

Design: Angiogenesis in livers of c57BL/6 mice upon carbon tetrachloride- or bile duct ligation-induced chronic hepatic injury was non-invasively monitored using in vivo contrast-enhanced micro computed tomography (µCT) and ex vivo anatomical µCT after hepatic Microfil perfusion. Functional contributions of monocyte-derived macrophage subsets for angiogenesis were explored by pharmacological inhibition of CCL2 using the Spiegelmer mNOX-E36.

Results: Contrast-enhanced in vivo µCT imaging allowed non-invasive monitoring of the close correlation of angiogenesis, reflected by functional hepatic blood vessel expansion, with experimental fibrosis progression. On a cellular level, inflammatory monocyte-derived macrophages massively accumulated in injured livers, colocalised with newly formed vessels in portal tracts and exhibited pro-angiogenic gene profiles including upregulated VEGF and MMP9. Functional in vivo and anatomical ex vivo µCT analyses demonstrated that inhibition of monocyte infiltration by targeting the chemokine CCL2 prevented fibrosis-associated angiogenesis, but not fibrosis progression. Monocyte-derived macrophages primarily fostered sprouting angiogenesis within the portal vein tract. Portal vein diameter as a measure of portal hypertension depended on fibrosis, but not on angiogenesis.

Conclusions: Inflammation-associated angiogenesis is promoted by CCL2-dependent monocytes during fibrosis progression. Innovative in vivo µCT methodology can accurately monitor angiogenesis and antiangiogenic therapy effects in experimental liver fibrosis.


Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aptamers, Nucleotide / pharmacology*
  • Carbon Tetrachloride / pharmacology
  • Chemokine CCL2* / antagonists & inhibitors
  • Chemokine CCL2* / metabolism
  • Disease Models, Animal
  • Disease Progression
  • Inflammation / metabolism
  • Liver / pathology
  • Liver Cirrhosis* / complications
  • Liver Cirrhosis* / etiology
  • Liver Cirrhosis* / metabolism
  • Liver Cirrhosis* / pathology
  • Liver Cirrhosis* / physiopathology
  • Macrophages* / metabolism
  • Macrophages* / pathology
  • Mice
  • Mice, Inbred C57BL
  • Neovascularization, Pathologic* / etiology
  • Neovascularization, Pathologic* / metabolism
  • Neovascularization, Pathologic* / pathology
  • Neovascularization, Pathologic* / prevention & control
  • X-Ray Microtomography / methods


  • Aptamers, Nucleotide
  • Chemokine CCL2
  • NOX-E36-3'PEG, mouse
  • Carbon Tetrachloride