Pl(A2) polymorphism of beta(3) integrins is associated with enhanced thrombin generation and impaired antithrombotic action of aspirin at the site of microvascular injury.
BACKGROUND
Mechanisms by which the Pl(A2) (Leu33Pro) polymorphism of beta(3) integrins could lead to an increased risk for coronary events are unclear. This study was designed to examine the effect of this polymorphism on blood coagulation.


RESULTS
In normal subjects (12 with Pl(A1A1), 9 with Pl(A1A2), and 3 with Pl(A2A2)), we evaluated the activation of prothrombin, factor V, and factor XIII and fibrinogen removal by quantitative immunoblotting; thrombin-antithrombin III complex generation using ELISA; and levels of fibrinopeptide A and B by high-performance liquid chromatography in blood collected every 30 seconds at sites of standardized microvascular injury before and after 7 days of aspirin ingestion (75 mg/d). Compared with the Pl(A1A1) subjects, the Pl(A2) carriers exhibited higher maximum rates of thrombin B-chain generation (by 31.6%; P=0.005), thrombin-antithrombin III complex generation (by 30.7%; P=0.003), fibrinogen consumption (by 31.3%; P=0.002), prothrombin consumption (by 26.1%; P=0.011), and activation of factor V (by 14.1%; P=0.033) and factor XIII (by 27.0%; P=0.012). In the Pl(A1A1) homozygotes, aspirin ingestion resulted in reductions in the velocity of thrombin B-chain formation (by 32.1%; P=0.007), prothrombin consumption (by 30.4%; P=0.018), factor Va generation (by 28.9%; P=0.014), fibrinogen removal (by 41.2%; P=0.001), and factor XIII activation (by 22.6%; P=0.026). In the Pl(A2) carriers, aspirin did not alter the velocity of all these processes. After aspirin ingestion, fibrinopeptide A and B concentrations in the last 30-second interval were significantly reduced, but only in the Pl(A1A1) subjects.


CONCLUSIONS
The presence of the Pl(A2) allele is associated with enhanced thrombin formation and an impaired antithrombotic action of aspirin, which might favor coronary thrombosis in the Pl(A2) carriers.
Undas
A
A
Department of Medicine, Jagellonian University School of Medicine, Krakow, Poland.
Brummel
K
K
Musial
J
J
Mann
K G
KG
Szczeklik
A
A
D000328:Adult; D000483:Alleles; D015703:Antigens, CD / Q000378:metabolism*; D001241:Aspirin / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects / Q000235:genetics*; D001780:Blood Coagulation Tests; D003328:Coronary Thrombosis / Q000235:genetics* / Q000378:metabolism; D005165:Factor V / Q000378:metabolism; D005176:Factor XIII / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D005343:Fibrinolytic Agents / Q000494:pharmacology; D005820:Genetic Testing; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D039661:Integrin beta3; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D010741:Phospholipases A / Q000235:genetics* / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D011110:Polymorphism, Genetic; D011516:Prothrombin / Q000378:metabolism; D012867:Skin / Q000098:blood supply; D013917:Thrombin / Q000096:biosynthesis*
D015703:Antigens, CD; D005343:Fibrinolytic Agents; D039661:Integrin beta3; D010980:Platelet Membrane Glycoproteins; D005165:Factor V; D011516:Prothrombin; D005340:Fibrinogen; D005176:Factor XIII; D010741:Phospholipases A; D013917:Thrombin; D001241:Aspirin