title: Characterizing patterns of endothelialization following coil embolization: a whole-mount, dual immunostaining approach.
abstract: BACKGROUND
  The extent, rate, and source of endothelialization following coil embolization of saccular aneurysms remains poorly understood. We performed a whole tissue mount, dual immunohistochemical analysis of experimental aneurysms to characterize the state of endothelialization over time after platinum coil embolization.
  
  
  METHODS
  Elastase-induced rabbit aneurysms were created and treated with bare platinum coils. Samples were harvested at 4 and 8 weeks (n=6 for each). En face whole tissue mount staining with antibodies to CD31 and α-smooth muscle actin was used to identify endothelial cells and smooth muscle cells, respectively. Sytox green stain was used to demonstrate nuclear morphology for identification of inflammatory cells. The extent of endothelialization was measured in relation to the aneurysm neck-parent artery interface.
  
  
  RESULTS
  At 4 weeks after coil embolization, very localized membranous tissue and neoendothelial cells were detected on the coil loops immediately adjacent to the parent artery-neck interface, but the remainder of the coil loops remained devoid of endothelial cells. At 8 weeks neoendothelial cells were more confluent over the coils than at 4 weeks, and extended up to 900 µm from the parent artery-neck interface. However, the surfaces of the coils farther away than this region harbored no endothelial cells. Scattered inflammatory cells, including neutrophils and monocytes, were seen on the coil surface at the neck central area, where the coil surface was bare at the 4 and 8 weeks' follow-up.
  
  
  CONCLUSIONS
  Platinum coil embolization supports gradual but limited endothelialization, where endothelial cells migrate directly from the adjacent parent artery.
authors: Neuroradiology Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Daying
authors: D
authors: Dai
authors: Neuroradiology Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Yong-Hong
authors: YH
authors: Ding
authors: Neuroradiology Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Issa
authors: I
authors: Rezek
authors: Neuroradiology Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: David F
authors: DF
authors: Kallmes
authors: Neuroradiology Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Ramanathan
authors: R
authors: Kadirvel
mesh_terms: D000783:Aneurysm / Q000139:chemically induced / Q000175:diagnosis* / Q000601:surgery*; D000818:Animals; D004621:Embolization, Therapeutic / Q000639:trends*; D005260:Female; D010196:Pancreatic Elastase / Q000633:toxicity*; D010984:Platinum; D011817:Rabbits; D013194:Staining and Labeling / Q000379:methods*; D015607:Stents
chemical_list: D010984:Platinum; D010196:Pancreatic Elastase
keywords: Aneurysm; Vessel Wall
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