Fatty acid amide hydrolase deficiency enhances intraplaque neutrophil recruitment in atherosclerotic mice

Arterioscler Thromb Vasc Biol. 2013 Feb;33(2):215-23. doi: 10.1161/ATVBAHA.112.300275. Epub 2012 Dec 13.

Abstract

Objective: Endocannabinoid levels are elevated in human and mouse atherosclerosis, but their causal role is not well understood. Therefore, we studied the involvement of fatty acid amide hydrolase (FAAH) deficiency, the major enzyme responsible for endocannabinoid anandamide degradation, in atherosclerotic plaque vulnerability.

Methods and results: We assessed atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) and ApoE(-/-)FAAH(-/-) mice. Before and after 5, 10, and 15 weeks on high-cholesterol diet, we analyzed weight, serum cholesterol, and endocannabinoid levels, and atherosclerotic lesions in thoracoabdominal aortas and aortic sinuses. Serum levels of FAAH substrates anandamide, palmitoylethanolamide (PEA), and oleoylethanolamide (OEA) were 1.4- to 2-fold higher in case of FAAH deficiency. ApoE(-/-)FAAH(-/-) mice had smaller plaques with significantly lower content of smooth muscle cells, increased matrix metalloproteinase-9 expression, and neutrophil content. Circulating and bone marrow neutrophil counts were comparable between both genotypes, whereas CXC ligand1 levels were locally elevated in aortas of FAAH-deficient mice. We observed enhanced recruitment of neutrophils, but not monocytes, to large arteries of ApoE(-/-) mice treated with FAAH inhibitor URB597. Spleens of ApoE(-/-)FAAH(-/-) mice had reduced CD4+FoxP3+regulatory T-cell content, and in vitro stimulation of splenocytes revealed significantly elevated interferon-γ and tumor necrosis factor-α production in case of FAAH deficiency.

Conclusions: Increased anandamide and related FAAH substrate levels are associated with the development of smaller atherosclerotic plaques with high neutrophil content, accompanied by an increased proinflammatory immune response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidohydrolases / antagonists & inhibitors
  • Amidohydrolases / deficiency*
  • Amidohydrolases / genetics
  • Animals
  • Aorta / drug effects
  • Aorta / enzymology*
  • Aorta / immunology
  • Aorta / pathology
  • Aortic Diseases / enzymology*
  • Aortic Diseases / genetics
  • Aortic Diseases / immunology
  • Aortic Diseases / pathology
  • Apolipoproteins E / deficiency
  • Apolipoproteins E / genetics
  • Arachidonic Acids / blood
  • Atherosclerosis / enzymology*
  • Atherosclerosis / genetics
  • Atherosclerosis / immunology
  • Atherosclerosis / pathology
  • Benzamides / pharmacology
  • Carbamates / pharmacology
  • Cells, Cultured
  • Chemokine CXCL1 / metabolism
  • Cholesterol / blood
  • Disease Models, Animal
  • Endocannabinoids / blood
  • Enzyme Inhibitors / pharmacology
  • Ethanolamines / blood
  • Genotype
  • Inflammation Mediators / metabolism
  • Interferon-gamma / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Muscle, Smooth, Vascular / immunology
  • Muscle, Smooth, Vascular / pathology
  • Neutrophil Infiltration* / drug effects
  • Neutrophils / drug effects
  • Neutrophils / immunology*
  • Oleic Acids / blood
  • Palmitic Acids / blood
  • Phenotype
  • Plaque, Atherosclerotic
  • Polyunsaturated Alkamides / blood
  • Spleen / immunology
  • T-Lymphocytes, Regulatory / immunology
  • Time Factors
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Apolipoproteins E
  • Arachidonic Acids
  • Benzamides
  • Carbamates
  • Chemokine CXCL1
  • Cxcl1 protein, mouse
  • Endocannabinoids
  • Enzyme Inhibitors
  • Ethanolamines
  • Inflammation Mediators
  • Oleic Acids
  • Palmitic Acids
  • Polyunsaturated Alkamides
  • Tumor Necrosis Factor-alpha
  • cyclohexyl carbamic acid 3'-carbamoylbiphenyl-3-yl ester
  • oleoylethanolamide
  • palmidrol
  • Interferon-gamma
  • Cholesterol
  • Matrix Metalloproteinase 9
  • Mmp9 protein, mouse
  • Amidohydrolases
  • fatty-acid amide hydrolase
  • anandamide