PlA2 Polymorphism in Glycoprotein IIb/IIIa Modulates the Morphology and Nanomechanics of Platelets.

Glycoprotein IIb/IIIa (GPIIb/IIIa) is the most abundant platelet surface receptor for fibrinogen and von Willebrand factor. Polymorphism PlA1/A2 in the gene of GPIIb/IIIa is among the risk factors for the development of arterial and venous thrombosis. The aim of this study is to evaluate the effect of the carriage of PlA1/A2 on the size, topographic features, and membrane stiffness of platelets from healthy controls and patients with deep venous thrombosis (DVT). Atomic force microscopy (AFM) imaging and nanoindentation (force-distance curves) were applied to investigate the morphological and nanomechanical properties (Young's modulus) of platelets immobilized on glass surface. The surface roughness ( Ra) and height ( h) of platelets from patients with DVT, carriers of mutant allele PlA2 ( Ra = 30.2 ± 6 nm; h = 766 ± 182 nm) and noncarriers ( Ra = 28.6 ± 6 nm; h = 865 ± 290 nm), were lower than those of healthy carriers of allele PlA2 ( Ra = 48.1 ± 12 nm; h = 1072 ± 338 nm) and healthy noncarriers ( Ra = 49.7 ± 14 nm; h = 1021 ± 433 nm), respectively. Platelets isolated from patients with DVT, both carriers and noncarriers, exhibit much higher degree of stiffness at the stage of spreading ( E = 327 ± 85 kPa and 341 ± 102 kPa, respectively) compared to healthy noncarriers ( E = 198 ± 50 kPa). In addition, more pronounced level of platelet activation was found in polymorphism carriers. In conclusion, the carriage of PlA2 allele modulates the activation state, morphology, and membrane elasticity of platelets.

Rs5918ITGB3 Polymorphism, Smoking, and BMI as Risk Factors for Early Onset and Recurrence of DVT in Young Women.

OBJECTIVE: To evaluate the contribution of rs5918ITGB3 on the incidence and recurrence of deep venous thrombosis (DVT) in women and the relationship with body mass index (BMI) and smoking and to compare with data in men. RESULTS: Rs5918(C) polymorphism in ITGB3 gene was assessed in 224 patients diagnosed with DVT and 216 controls. Thrombophilic genetic variant rs5918(C) was significantly pronounced in women (χ2 =7.565, P = .008) and total patients (χ2 = 9.266, P = .002) but not in men. Women patients (<45 years) who were carriers of rs5918ITGB3 polymorphism had an early onset of DVT (34.5 vs 39.4 years, χ2 = 7.027, P = .008) as analyzed by Kaplan-Meier and a higher risk of the recurrent event (χ2 = 3.405, odds ratio = 2.581, P = .044). The period before recurrent venous thromboembolism event was related to smoking status and BMI in young female who were carriers of rs5918 polymorphism but not in the males. CONCLUSIONS: Carriage of genetic variant rs5918(C) polymorphism in ITGB3 gene in women contributes to higher risk of single and recurrent DVT events at younger age.