title: Ultrasound-enhanced thrombolytic effect of tissue plasminogen activator-loaded echogenic liposomes in an in vivo rabbit aorta thrombus model--brief report.
abstract: OBJECTIVE
  Ultrasound enhances thrombolysis when combined with a thrombolytic and a contrast agent. This study aimed to evaluate the thrombolytic effect of our tissue plasminogen activator (tPA)-loaded echogenic liposomes (ELIP) in an in vivo clot model, with and without ultrasound treatment.
  
  
  RESULTS
  The femoral arteries of New Zealand White rabbits (n=4 per group) were cannulated. The abdominal aortas were denuded, and thrombi were created using a solution of sodium ricinoleate plus thrombin. Rabbits were then randomly selected to receive tPA-loaded ELIP (200 μg of tPA/5 mg of lipid) or empty ELIP with or without pulsed (color) Doppler ultrasound (5.7 MHz) for 2 minutes. Thrombus was imaged and echogenicity analyzed before and after ELIP injection. Blood flow velocities were measured at baseline, after clot formation, and serially after treatment up to 15 minutes. tPA-loaded ELIP highlighted thrombus in the abdominal aorta more effectively than empty ELIP (P<0.05). Ultrasound enhanced the thrombolytic effect of tPA-loaded ELIP, resulting in earlier and more complete recanalization rates (P<0.001).
  
  
  CONCLUSIONS
  This study demonstrates effective highlighting of clots and thrombolytic effect of tPA-loaded ELIP in an in vivo rabbit aorta clot model. Doppler ultrasound treatment enhances this thrombolytic effect, resulting in earlier and more complete recanalization rates.
authors: Division of Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA. susan.t.laing@uth.tmc.edu
authors: Susan T
authors: ST
authors: Laing
authors: Melanie
authors: M
authors: Moody
authors: Beverly
authors: B
authors: Smulevitz
authors: Hyunggun
authors: H
authors: Kim
authors: Patrick
authors: P
authors: Kee
authors: Shaoling
authors: S
authors: Huang
authors: Christy K
authors: CK
authors: Holland
authors: David D
authors: DD
authors: McPherson
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal; D001018:Aortic Diseases / Q000628:therapy*; D008081:Liposomes; D008297:Male; D011817:Rabbits; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000628:therapy*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D014464:Ultrasonic Therapy
chemical_list: D008081:Liposomes; D010959:Tissue Plasminogen Activator