title: Monocytes are recruited from venules during arteriogenesis in the murine spinotrapezius ligation model.
abstract: OBJECTIVE
  Chronic arterial occlusion results in arteriogenesis of collateral blood vessels. This process has been shown to be dependent on the recruitment of growth-promoting macrophages to remodeling collaterals. However, the potential role of venules in monocyte recruitment during microvascular arteriogenesis is not well demonstrated. First, we aim to document that arteriogenesis occurs in the mouse spinotrapezius ligation model. Then, we investigate the temporal and spatial distribution, as well as proliferation, of monocytes/macrophages recruited to collateral arterioles in response to elevated fluid shear stress.
  
  
  RESULTS
  Laser speckle flowmetry confirmed a postligation increase in blood velocity within collateral arterioles but not within venules. After 72 hours post ligation, collateral arteriole diameters were increased, proliferating cells were identified in vessel walls of shear-activated collaterals, and perivascular CD206(+) macrophages demonstrated proliferation. A 5-ethynyl-2'-deoxyuridine assay identified proliferation. CD68(+)CD206(+) cells around collaterals were increased 96%, whereas CX3CR1((+/GFP)) cells were increased 126% in ligated versus sham groups after 72 hours. CX3CR1((+/GFP)) cells were predominately venule associated at 6 hours after ligation; and CX3CR1((+/GFP hi)) cells shifted from venule to arteriole associated between 6 and 72 hours after surgery exclusively in ligated muscle. We report accumulation and extravasation of adhered CX3CR1((+/GFP)) cells in and from venules, but not from arterioles, after ligation.
  
  
  CONCLUSIONS
  Our results demonstrate that arteriogenesis occurs in the murine spinotrapezius ligation model and implicate postcapillary venules as the site of tissue entry for circulating monocytes. Local proliferation of macrophages is also documented. These data open up questions about the role of arteriole-venule communication during monocyte recruitment.
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville.
authors: Anthony C
authors: AC
authors: Bruce
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville.
authors: Molly R
authors: MR
authors: Kelly-Goss
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville.
authors: Joshua L
authors: JL
authors: Heuslein
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville.
authors: Joshua K
authors: JK
authors: Meisner
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville.
authors: Richard J
authors: RJ
authors: Price
authors: From the Department of Biomedical Engineering, University of Virginia, Charlottesville. smp6p@virginia.edu.
authors: Shayn M
authors: SM
authors: Peirce
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001160:Arterioles; D000073883:CX3C Chemokine Receptor 1; D002455:Cell Division; D004730:Endothelium, Vascular / Q000473:pathology; D005260:Female; D017930:Genes, Reporter; D018056:Hemorheology; D007511:Ischemia / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry; D037181:Lectins, C-Type / Q000032:analysis; D008026:Ligation; D008297:Male; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000032:analysis; D019707:Receptors, Chemokine / Q000032:analysis / Q000235:genetics; D014699:Venules / Q000473:pathology*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000073883:CX3C Chemokine Receptor 1; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D019707:Receptors, Chemokine; C081026:CD68 protein, mouse; D000097382:CD68 Molecule; C471885:Cx3cr1 protein, mouse
keywords: arterioles; blood flow velocity; macrophages; microvasculature; monocytes