Multilocus Analysis of Genetic Susceptibility to Myocardial Infarction in Russians: Replication Study.

In search of genetic markers of myocardial infarction (MI) risk, which have prognostic significance for Russians, we performed a replication study of MI association with genetic variants of PCSK9 (rs562556), APOE (epsilon polymorphism, rs7412 and rs429358), LPL (rs320), MTHFR (rs1801133), eNOS (rs2070744), and the 9p21 region (rs1333049) in 405 patients with MI and 198 controls. Significant MI association was observed with variants of the lipid metabolism genes (PCSK9, APOE and LPL), and of eNOS. The SNPs in the MTHFR gene and the 9p21 region were not significantly associated with MI one by one but were included in several different MI-associated allelic combinations identified by multilocus analysis. Since we have not revealed nonlinear epistatic interactions between the components of the identified combinations, we postulate that the cumulative effect of genes that form a combination arises from the summation of their small independent contributions. The prognostic significance of the additive composite model built from the PCSK9, APOE, LPL, and eNOS genes as genetic markers was assessed using ROC analysis. After we included these markers in the previously published composite model of individual genetic risk of MI, the prognostic efficacy in our sample reached AUC = 0.676. However, the results obtained in this study certainly need to be replicated in an independent sample of Russians.

Platelet subpopulation bearing leukocyte specific antigen and tissue factor.

Platelets bearing leukocyte antigen CD45 were identified in the blood of patients with myocardial infarction (MI) and healthy donors by flow cytofluorimetry. Part of these platelets contained tissue factor (TF)-primary initiator of blood clotting. The number of CD45+ and CD45+/TF+ platelets in MI patients at the first day was comparable with their level in healthy donors, but was increased at 8-12 days after MI onset. At that time in some patients the amount of CD45+ and CD45+/TF+ platelets reached 5-6 and 2-3% of their total number. It is assumed that CD45+/TF+ platelets could be formed as a result of platelet interaction with leukocytes or leukocyte produced membrane microparticles.

[Combined Effect of Genetic Factors, Age, and Smoking on the Risk of Developing Myocardial Infarction].

OBJECTIVE: to elaborate a complex model for myocardial infarction (MI) risk assessment considering the combined effect of genetic predisposition, age and smoking. MATERIALS AND METHODS: The study included two independent samples of ethnic Russians: 325 patients with MI and 185 individuals without history of cardiovascular diseases (controls) from the Moscow region, and 220 patients and 197 controls from the Republic of Bashkortostan. Genotyping of polymorphic loci of genes CRP (rs1130864), IFNG (rs2430561), TGFB1 (rs1982073), FGB (rs1800788) and PTGS1 (rs3842787) was performed. To construct the predictive models, we used logistic regression with stepwise inclusion of variables. The predictive value was evaluated by the area under the curve (AUC) in a ROC-analysis. The factor was considered as a marker at pAUC <0.05 calculated by the method of DeLong. The marker was considered effective at AUC >0.60. RESULTS: Three separate genetic variants FGB rs1800788*T, TGFB1 rs1982073*TT, CRP rs1130864*TT, and biallelic combination IFNG rs2430561*A + PTGS1 rs3842787*T whose association with MI we described earlier, were used to construct the composite genetic marker (AUC=0.66 in the training and test samples) by the logistic regression method. Adding to the obtained composite genetic marker such parameters as age and smoking allowed to create a complex MI risk marker, which was characterized by the predictive value stability (AUC=0.77 in the training sample and 0.82 in the test sample). CONCLUSION: The obtained complex model for MI risk assessment was reproduced in two independent samples of Russian ethnicity individuals from different regions of Russia with different gender identities, and allowed to have a reasonable chance (about 80%) of distinguishing patients and healthy individuals.

[Comparison of Atherosclerotic Lesions in Patients With Acute Myocardial Infarction and Stable Angina Pectoris Using Intravascular Ultrasound].

AIM: to compare noninfarct-related lesions in patients with acute myocardial infarction (MI) with culprit and non-culprit lesions in patients with stable angina pectoris (SAP) using intravascular ultrasound virtual histology (VH-IVUS). MATERIAL AND METHODS: Overall 70 patients were enrolled: 38 with ST elevation (STE) MI and 32 with stable angina pectoris (SAP). All patients underwent three-vessel coronary angiography and gray-scale and VH-IVUS after percutaneous coronary intervention (PCI) of infarct-related lesion in STEMI or culprit lesion in SAP. RESULTS: A total of 130 plaques were examined: 70 in patients with STEMI and 60 in patients with SAP. Noninfarct-related lesions in acute MI compared with non-culprit lesions in SAP had significantly larger plaque burden and plaque volume, smaller minimum lumen area, and more positive remodeling. STEMI, hyperlipidemia, plaque burden, and hypertension were independent predictors of unstable plaques.

[Comparison of Atherosclerotic Lesions in Patients With Acute Myocardial Infarction and Stable Angina Pectoris Using Intravascular Ultrasound].

AIM: to compare noninfarct-related lesions in patients with acute myocardial infarction (MI) with culprit and non-culprit lesions in patients with stable angina pectoris (SAP) using intravascular ultrasound virtual histology (VH-IVUS). MATERIAL AND METHODS: Overall 70 patients were enrolled: 38 with ST elevation (STE) MI and 32 with stable angina pectoris (SAP). All patients underwent three-vessel coronary angiography and gray-scale and VH-IVUS after percutaneous coronary intervention (PCI) of infarct-related lesion in STEMI or culprit lesion in SAP.

Spontaneous platelet aggregation in patients with acute coronary syndrome.

Spontaneous platelet aggregation was evaluated in patients with acute coronary syndrome on days 1, 3-5, and 8-12 of the disease. On day 1, aggregation was analyzed after aspirin, but before clopidogrel administration; during other periods after both antiaggregants. The mean levels of spontaneous aggregation after antithrombotic therapy did not change during different periods after the onset of acute coronary syndrome, in contrast to ADP-induced aggregation that decreased after the development of clopidogrel effects (days 3-5 and 8-12). Spontaneous aggregation during different periods directly correlated (r>0.4, p<0.01) with spontaneous and ADP-induced aggregation during different periods (r=0.372, r=0.447, and r=0.543 on days 1, 3-5, and 8-12, respectively; p<0.01). No relationship between spontaneous aggregation and plasma concentration of von Willebrand's factor was detected. Spontaneous aggregation was completely suppressed after in vitro addition of prostaglandin E1 (platelet activation inhibitor), slightly (by ≈20%) decreased in the presence of antibodies to glycoprotein Ib, blocking its reactions with von Willebrand's factor, and did not change in the presence of aptamer inhibiting thrombin activity.

Glycoprotein IIb-IIIa content and platelet aggregation in healthy volunteers and patients with acute coronary syndrome.

Glycoprotein (GP) IIb-IIIa (αIIbß3-integrin) is the central receptor of platelet aggregation. Activated GP IIb-IIIa binds fibrinogen or von Willebrand factor, which forms molecular bridges between aggregating platelets. This review summarizes data on the relationship between GP IIb-IIIa expression on the platelet surface and platelet aggregating activity. GP IIb-IIIa number, measured as maximal binding of complex-specific monoclonal antibody, varied by approximately two fold in both healthy volunteers (n = 35) and patients with acute coronary syndrome (ACS) (n = 65). In healthy volunteers positive associations were observed between GP IIb-IIIa number and the level of ADP-induced aggregation when this relationship was analysed in untreated platelet-rich plasma (PRP) as well as upon in vitro addition of aspirin or non-saturating concentrations of GP IIb-IIIa blockers. In the same group of volunteers almost no differences in aggregating activity were detected between donors carrying the GP IIIa Pro33 allele (n = 15) and those with the GP IIIa Leu33Leu33 genotype (n = 20). No significant relationships were revealed between platelet aggregability and variations of plasma fibrinogen concentration. Positive correlation of the level of ADP-induced aggregation and GP IIb-IIIa content was detected in patients with ACS within the first hour upon admission to the hospital when they had already received aspirin, but not clopidogrel. However, there were no correlations between these parameters at days 3-5 and days 8-12 (before discharge). At these time points patients were treated not only with aspirin but were saturated with clopidogrel as well. In ACS patients we also evaluated the expression of another platelet adhesive receptor, GP Ib, and found a significant positive correlation between GP IIb-IIIa and GP Ib content. A strong association was also revealed between the number of both receptors and mean platelet volume. The latter observation indicated that individual variations of the number of glycoprotein molecules are mainly affected by platelet size but not the density of their expression on the platelet membrane. Possible usefulness of measuring GP IIb-IIIa content as a marker of increased platelet reactivity is discussed.

[Glycoprotein IIb-IIIa antagonist Monafram in primary angioplasty of patients with acute coronary syndrome without st segment elevation].

Glycoprotein (GP) llb-llla anagonist monafram is the F(ab)2 fragments of anti GP llb llla monoclonal antibody FraMon (CRC64). Efficacy and safety of monafram in primary coronary angioplasty of patients with acute coronary syndrome without ST segment elevation (non ST ACS) was evaluated in this study. Monafram was introduced intravenously to 284 patients just before angioplasty at standard dosage - 0.25 mg/kg as single i.v. bolus. Control group included 203 patients. All patients received aspirin (loading dose 300 mg and then 75 mg daily) and more than 90% - clopidogrel (loading dose 300-600 mg and then 75 mg daily). Within 30 days of follow up period monafram decreased by more than 2.5 fold the total amount of unfavorable outcomes (cardiovascular death, myocardial infarction and indications for repeat revascularization due to angina recurrence) - from 19.2% to 7.4% (p<0.001). The rate of indications for revascularization was most strongly decreased - by more than 7 times - from 7.9% to 1.1% (p<0.001). The number of myocardial infarctions was reduced by more than 2 times - from 8.4% to 3.9% (p=0.057). The amount of lethal outcomes did not differ between two groups (2.9% and 2.4% in the control and monafram groups, respectively). In the control group 8.9% patients received monafram during primary angioplasty due to urgent indications. Monafram did not cause any allergic reaction in all tested patients. Major bleeding was registered in one (less than 0.5%) and deep thrombocytopenia (<20000 platelets per 1 ul) - in 3 (1.1%) out of 284 patients. The data obtained indicated that monafram decreased the number of thrombotic complications in non ST ACS patients undergoing angioplasty upon the dual antiplatelet therapy (aspirin+clopidogrel) and without significant increase of dangerous side effects.

Safety, inhibition of platelet aggregation and pharmacokinetics of Fab'2 fragments of the anti-glycoprotein IIb-IIIa monoclonal antibody FRaMon in high-risk coronary angioplasty.

The purpose of the study was to evaluate safety, effects on platelet aggregation and pharmacokinetics of F(ab')(2) fragments of anti-glycoprotein (GP) IIb-IIIa murine monoclonal antibody FRaMon (F(ab')(2) FRaMon) upon its intravenous administration in patients undergoing high-risk coronary angioplasty. Patients were treated before angioplasty with F(ab')(2) FRaMon at 0.2 mg/kg (n = 17) and 0.25 mg/kg (n = 12) bolus or with abciximab at 0.25 mg/kg bolus + 12 h infusion at 0.125 microg/kg per min (n = 29). F(ab')(2) FRaMon at both doses decreased platelet aggregation induced by 20 microM ADP to <10, <20, <40 and <70% of the predrug level at 1, 12, 24 and 72 h after injection, respectively. No significant differences were observed between F(ab')(2) FRaMon and abciximab antiaggregatory effects. In none of the patients did F(ab')(2) FRaMon cause allergic reactions, major bleedings or deep thrombocytopenia. Antibodies against F(ab')(2) FRaMon were detected in one patient. Free F(ab')(2) FRaMon was cleared from plasma within 12 h, while platelet-bound preparation occupied >95, 70-80 and 40-50% of GP IIb-IIIa at 1 and 12-24 h and 3 days after injection, respectively. Thrombotic complications within the first month after angioplasty in groups treated with F(ab')(2) FRaMon and abciximab were observed in one and two patients, respectively. The data obtained have shown that F(ab')(2) FRaMon at bolus administration to patients undergoing coronary angioplasty caused no serious side effects and at comparative dosage inhibited platelet aggregation with the same efficacy as abciximab at bolus + infusion administration.