Thrombolysis by thienopyridines and their congeners.
We propose that anti-platelet thienopyridines, such as ticlopidine or clopidogrel, are thrombolytic owing to endothelial release of prostacyclin (PGI2) and tissue plasminogen activator (t-PA). In this study we used anaesthetised Wistar rats with extracorporal circulation in which arterial blood superfused thrombi which adhered to a strip of collagen. Weight of thrombi was continuously monitored. When administered intravenously, clopidogrel or its R enantiomer deprived of anti-platelet action, both at doses of 3 mg x kg(-1), produced lost in weight of thrombi by 14.1 +/- 1.3% or 16.0 +/- 1.4% (n = 9), and at doses 10 mg x kg(-1) by 28.3 +/- 2.3% or 30.4 +/- 1.9% (n = 8), respectively. Maximum of thrombolysis occurred 30-45 min following the drug administration. Ticlopidine at a dose of 30 mg x kg(-1) reduced weight of thrombi by 33.7 +/- 1.7% (n = 32). Thrombolytic action of ticlopidine was accompanied by a rise in 6!keto-PGF1alpha blood levels from 0.42 +/- 0.10 to 1.58 +/- 0.29 ng x ml(-1) and t-PA antigen plasma levels from 4.70 +/- 1.00 to 12.90 +/- 1.15 ng x ml(-1) (n = 7). Five out of eleven tested thienopyridine congeners with pyrimidine or pyrimidinone instead of pyridine rings had thrombolytic potencies similar to that of clopidogrel (ED30s at a range of 6.2-11.4 mg x kg(-1)). A substantial increase in thrombolytic potency (ED30s at a range of 0.3-2.1 mg x kg(-1)) was observed for congeners in which thienyl ring was condensed with an additional cyclopentyl, cyclohexyl or cycloheptyl structures or in which thienopyridine complex was replaced for a pyridopyrimidine one. We claim that thienopyridines, independently of their delayed anti-platelet action, do produce immediate thrombolysis in vivo. This new activity emulates capacity of their native, non-metabolised molecules to release prostacyclin and tissue plasminogen activator. We have also shown that structural changes in molecules of thienopyridines may intensify their thrombolytic potency.
Gryglewski
R J
RJ
Chair of Pharmacology, Medical College of Jagiellonian University, Cracow, Poland.
Dupin
J P
JP
Uracz
W
W
Swiês
J
J
Madej
J
J
Hou
G
G
Gravier
D
D
Casadebaig
F
F
D000818:Animals; D000077144:Clopidogrel; D005112:Extracorporeal Circulation; D005343:Fibrinolytic Agents / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008297:Male; D015394:Molecular Structure; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine