Iohexol, platelet activation and thrombosis. I. Iohexol-induced platelet secretion does not affect thrombus formation in native blood.
BACKGROUND
The nonionic monomer iohexol triggers in vitro platelet secretion of beta-thromboglobulin (beta-TG). This iohexol platelet activation may promote intravascular thrombosis. We studied this relationship by employing a human model of collagen-induced platelet thrombus formation at arterial flow. The ionic dimer ioxaglate, the nonionic dimer iodixanol, and glucose were included.


RESULTS
In vitro platelet activation as measured by beta-TG secretion following a 1-min incubation of native blood with 50 vol% of iohexol was significant. Glucose solutions of 300, 580 and 825 mosmol, corresponding to the osmolalities of respectively iodixanol, ioxaglate and iohexol, increased the beta-TG secretion in parallel with the osmolalities. Ioxaglate and iodixanol were virtually inert. Continuous infusion of iohexol or 580 or 825 mosmol glucose (40 vol%) into flowing native blood at an arterial wall shear rate of 2600 s-1 in an ex vivo collagen-induced platelet thrombus formation device triggered pronounced secretion of beta-TG. However, the platelet thrombus formation in blood mixed with iohexol was within the same range as that observed with ioxaglate or iodixanol. Increasing glucose osmolality induced increasing beta-TG secretion, which paralleled gradually decreasing platelet thrombus formation.


CONCLUSIONS
Iohexol and 580 or 825 mosmol glucose trigger platelet secretion of beta-TG. This secretion is not associated with enhanced collagen-induced platelet thrombus formation at high arterial shear.
Sakariassen
K S
KS
Nycomed Imaging AS, Bioreg Research, Oslo, Norway.
Barstad
R M
RM
Hamers
M J
MJ
Stormorken
H
H
D001782:Blood Donors; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism*; D003094:Collagen; D003287:Contrast Media / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D007472:Iohexol / Q000494:pharmacology*; D007485:Ioxaglic Acid / Q000494:pharmacology; D008297:Male; D015539:Platelet Activation / Q000187:drug effects*; D013927:Thrombosis / Q000097:blood / Q000139:chemically induced*; D014283:Triiodobenzoic Acids / Q000494:pharmacology; D001620:beta-Thromboglobulin / Q000032:analysis / Q000187:drug effects / Q000378:metabolism
D003287:Contrast Media; D014283:Triiodobenzoic Acids; D001620:beta-Thromboglobulin; D007472:Iohexol; D003094:Collagen; C044834:iodixanol; D007485:Ioxaglic Acid