The effects of Levovist and DD-723 in activating platelets and damaging hepatic cells of rats.
OBJECTIVE
The purpose of this study was to compare platelet activation and hepatic cell damage produced by 2 ultrasonographic contrast agents with flow cytometric and ultrastructural analysis.


METHODS
Suspension samples were made by mixing Levovist (SH U508A; Schering AG, Berlin, Germany) or DD-723 (Nycomed; Amersham Health, Princeton, NJ) with whole blood. The final concentrations of Levovist in citrated whole blood were 0, 15, and 75 mg/mL, and those of DD-723 were 0, 5, and 50 microL/mL. After exposure to ultrasound in vitro, flow cytometric analysis was performed to determine the concentration of the CD62P activation-specific antigen. To compare the hepatic cell damage associated with these 2 agents, we divided 15 rats into 5 groups as follows: group 1, sham operation; group 2, Levovist injection only; group 3, DD-723 injection only; group 4, Levovist injection (contrast agent) and ultrasound exposure; and group 5, DD-723 injection and ultrasound exposure. The ultrasonographic contrast agents Levovist and DD-723 were administered through the femoral vein and sonicated continuously for the first minute; this was followed by sweeping for 5 minutes 10 seconds after the contrast agent was injected. The rats were perfused via the heart with a fixative solution immediately after the sweeping, and then the liver was excised; the specimens were studied with electron and light microscopy.


RESULTS
The percentage of CD62P-expressing platelets increased in both contrast agent-ultrasound exposure groups, and the percentage of CD62P-expressing platelets was greater in the Levovist group. We observed vacuolation and round deposits in the hepatocytes in both contrast agent-ultrasound exposure groups. Microbubbles were observed in the rat Kupffer cells, and a few hepatocytes were seen unexpectedly in the DD-723 group but were found in neither the Kupffer cells nor the hepatocytes in the Levovist group.


CONCLUSIONS
Both contrast agents, Levovist and DD-723, produced platelet activation and structural change in the rat hepatic cells, but only the microbubbles of DD-723 were taken up by the Kupffer cells and a few hepatocytes.
Department of Clinical Laboratory Medicine, Jichi Medial School, Kawachi-gun, Tochigi-ken 329-0498, Japan. shigeta@jichi.ac.jp
Kouichirou
K
Shigeta
Kouichi
K
Itoh
Shigeo
S
Ookawara
Nobuyuki
N
Taniguchi
Kiyoka
K
Omoto
D000818:Animals; D003287:Contrast Media / Q000009:adverse effects / Q000494:pharmacology*; D005268:Femoral Vein; D005290:Ferric Compounds / Q000009:adverse effects / Q000494:pharmacology*; D005434:Flow Cytometry / Q000379:methods; D022781:Hepatocytes / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000648:ultrastructure; D066298:In Vitro Techniques; D007501:Iron / Q000009:adverse effects / Q000494:pharmacology*; D008099:Liver / Q000601:surgery; D008297:Male; D045423:Microbubbles; D008854:Microscopy, Electron / Q000379:methods; D010087:Oxides / Q000009:adverse effects / Q000494:pharmacology*; D019007:P-Selectin / Q000187:drug effects; D015539:Platelet Activation / Q000187:drug effects*; D011134:Polysaccharides / Q000009:adverse effects / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014463:Ultrasonography
D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; D019007:P-Selectin; D011134:Polysaccharides; C069727:Sonazoid; C059891:SHU 508; D007501:Iron