title: Contrast Ultrasound Imaging Does Not Affect Heat Shock Protein 70 Expression in Cholesterol-Fed Rabbit Aorta.
abstract: OBJECTIVE
  Diagnostic ultrasound imaging is enhanced by the use of circulating microbubble contrast agents (UCAs), but the interactions between ultrasound, UCAs, and vascular tissue are not fully understood. We hypothesized that ultrasound with a UCA would stress the vascular tissue and increase levels of heat shock protein 70 (Hsp70), a cellular stress protein.
  
  
  METHODS
  Male New Zealand White rabbits (n = 32) were fed a standard chow diet (n = 4) or a 1% cholesterol, 10% fat, and 0.11% magnesium diet (n = 28). At 21 days, 24 rabbits on the cholesterol diet were either exposed to ultrasound (3.2-MHz f/3 transducer; 2.1 MPa; mechanical index, 1.17; 10 Hz pulse repetition frequency; 1.6 microseconds pulse duration; 2 minutes exposure duration at 4 sites along the aorta) with the UCA Definity (1× concentration, 1 mL/min; Lantheus Medical Imaging, North Billerica, MA) or sham exposed with a saline vehicle injection (n = 12 per group). Four rabbits on the cholesterol diet and 4 on the chow diet served as cage controls and were not exposed to ultrasound or restrained for blood sample collection. Animals were euthanized 24 hours after exposure, and aortas were quickly isolated and frozen in liquid nitrogen. Aorta lysates from the area of ultrasound exposure were analyzed for Hsp70 level by Western blot. Blood plasma was analyzed for cholesterol, Hsp70, and von Willebrand factor, a marker of endothelial function.
  
  
  RESULTS
  Plasma total cholesterol levels increased to an average of 705 mg/dL. Ultrasound did not affect plasma von Willebrand factor, plasma Hsp70, or aorta Hsp70. Restraint increased Hsp70 (P < .001, analysis of variance).
  
  
  CONCLUSIONS
  Restraint, but not ultrasound with the UCA or cholesterol feeding, significantly increased Hsp70.
authors.affiliation: Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (B.W.S., R.J.M., W.D.O.), Division of Nutritional Sciences (B.W.S., J.W.E., W.D.O.), and Departments of Statistics (D.G.S.) and Food Science and Human Nutrition (J.W.E.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
authors.forename: Brendon W
authors.initials: BW
authors.lastname: Smith
authors.affiliation: Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (B.W.S., R.J.M., W.D.O.), Division of Nutritional Sciences (B.W.S., J.W.E., W.D.O.), and Departments of Statistics (D.G.S.) and Food Science and Human Nutrition (J.W.E.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Simpson
authors.affiliation: Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (B.W.S., R.J.M., W.D.O.), Division of Nutritional Sciences (B.W.S., J.W.E., W.D.O.), and Departments of Statistics (D.G.S.) and Food Science and Human Nutrition (J.W.E.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
authors.forename: Rita J
authors.initials: RJ
authors.lastname: Miller
authors.affiliation: Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (B.W.S., R.J.M., W.D.O.), Division of Nutritional Sciences (B.W.S., J.W.E., W.D.O.), and Departments of Statistics (D.G.S.) and Food Science and Human Nutrition (J.W.E.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Erdman
authors.affiliation: Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (B.W.S., R.J.M., W.D.O.), Division of Nutritional Sciences (B.W.S., J.W.E., W.D.O.), and Departments of Statistics (D.G.S.) and Food Science and Human Nutrition (J.W.E.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA. wdo@uiuc.edu.
authors.forename: William D
authors.initials: WD
authors.lastname: O'Brien
mesh_terms: D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging*; D015153:Blotting, Western; D002784:Cholesterol / Q000008:administration & dosage* / Q000097:blood*; D003287:Contrast Media / Q000378:metabolism*; D004032:Diet / Q000379:methods*; D018840:HSP70 Heat-Shock Proteins / Q000097:blood*; D007089:Image Enhancement; D008297:Male; D045423:Microbubbles; D011817:Rabbits; D014463:Ultrasonography; D014841:von Willebrand Factor
chemical_list: D003287:Contrast Media; D018840:HSP70 Heat-Shock Proteins; D014841:von Willebrand Factor; D002784:Cholesterol
keywords: atherosclerosis; cardiovascular disease; contrast agents; endothelium; heat shock protein 70; microbubbles; ultrasound