title: Temperature-sensitive poly(N-isopropylacrylamide-co-butyl methylacrylate) nanogel as an embolic agent: distribution, durability of vascular occlusion, and inflammatory reactions in the renal artery of rabbits.
abstract: OBJECTIVE
  We have developed a new thermosensitive liquid embolic agent, PIB nanogel, that can be solidified at body temperature. We thus further investigated the distribution, durability of vascular occlusion, and inflammatory reactions of PIB in embolization of the renal artery of rabbits.
  
  
  METHODS
  The bilateral renal arteries of 9 rabbits were first embolized with PIB at different injection rates. The distribution pattern of PIB was investigated by contact radiography and histology 1 hour after embolization. The right renal arteries of 20 rabbits were then embolized with PIB at the proper injection rate. Angiography and pathologic examination of the kidneys were performed at 1 week and 1, 2, and 3 months after embolization to evaluate the long-term outcomes.
  
  
  RESULTS
  With the injection rate increasing, PIB could reach the more distal branch of the renal artery. The proper injection rate was chosen as 0.10 mL/s due to the homogeneous distribution of PIB from the main renal artery to the precapillary level at this rate. During a 3-month follow-up observation period, no angiographic recanalization was observed. Histologically, we found no disruption of the vessel wall or subintimal bleeding, no extravasation of PIB, and no evidence of neovascularization. Moreover, there was only a mild inflammatory response, manifested by few lymphocytic and monocellular infiltration, without foreign body granuloma formation.
  
  
  CONCLUSIONS
  Embolization of the renal artery with PIB was easy and controllable, which could lead to a homogeneous and persistent occlusion without severe inflammatory changes. PIB might be a suitable material for intravascular embolization.
authors.affiliation: Department of Radiology, Union Hospital, Tongji Medical College, Wuhan, China.
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.forename: C
authors.initials: C
authors.lastname: Zheng
authors.forename: G
authors.initials: G
authors.lastname: Feng
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: H
authors.initials: H
authors.lastname: Liang
authors.forename: H
authors.initials: H
authors.lastname: Wu
authors.forename: G
authors.initials: G
authors.lastname: Zhou
authors.forename: B
authors.initials: B
authors.lastname: Liang
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Xia
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000009:adverse effects; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000379:methods*; D005782:Gels / Q000008:administration & dosage / Q000009:adverse effects; D006490:Hemostatics / Q000008:administration & dosage / Q000009:adverse effects; D053758:Nanoparticles / Q000008:administration & dosage* / Q000009:adverse effects; D011109:Polymethacrylic Acids / Q000627:therapeutic use*; D011817:Rabbits; D011859:Radiography; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging / Q000628:therapy*; D013696:Temperature; D016896:Treatment Outcome; D014657:Vasculitis / Q000209:etiology
chemical_list: D003692:Delayed-Action Preparations; D005782:Gels; D006490:Hemostatics; D011109:Polymethacrylic Acids; C084450:poly(N-isopropylacrylamide-co-butyl methacrylate)