Genetic determinants of acenocoumarol and warfarin maintenance dose requirements in Slavic population: a potential role of CYP4F2 and GGCX polymorphisms.

INTRODUCTION: VKORC1 and cytochrome CYP2C9 genetic variants contribute largely to inter-individual variations in vitamin K antagonists (VKAs) dose requirements. Cytochrome P450 4F2 isoform (CYP4F2), gamma-glutamyl carboxylase (GGCX) and apolipoprotein E (APOE) polymorphisms have been suggested to be of minor significance. MATERIALS AND METHODS: We sought to assess the impact of those polymorphisms on dose requirements in Central-Eastern European cohort of 479 patients receiving acenocoumarol (n=260) or warfarin (n=219). RESULTS: There were no differences between the acenocoumarol and warfarin groups with regard to the gender, age, body mass index and international normalized ratio. The VKORC1 c.-1639A allele carriers required a lower dose of acenocoumarol and warfarin than the non-carriers (28.0 [21.0-35.0] vs. 42.0 [28.0-56.0] mg/week, p<0.0001; 35.0 [28.0-52.0] vs. 52.0 [35.0-70.0] mg/week, p=0.0001, respectively). Carriers of 2 and/or 3 variant alleles for CYP2C9 also required a lower dose of warfarin as compared with 1 1 carriers (35.0 [31.5-52.5] vs. 43.8 [35.0-60.2] mg/week, p=0.02; 35.0 [23.5-35.0] vs. 43.8 [35.0-60.2] mg/week, p<0.0001, respectively). Similarly, possession of G allele of GGCX c.2084+45 polymorphism was associated with lower warfarin dose (35.0 [26.3-39.2] vs. 45.5 [35.0-65.1] mg/week, p=0.03). No effect of CYP2C9*2,-*3 and GGCX c.2084+45G>C polymorphisms on acenocoumarol dosage was observed. Interestingly, carriers of CYP4F2 c.1297A variant required a higher dose of acenocoumarol and warfarin than non-carriers (43.8 [35.0-60.2] vs. 35.0 [35.0-52.5] mg/week, p=0.01; 35.0 [28.0-52.5] vs. 28.0 [28.0-42.0] mg/week, p=0.05). CONCLUSIONS: We have shown for the first time, that besides VKORC1 and CYP2C9 genetic variants, the CYP4F2 c.1297A and GGCX c.2084+45G have a moderate effect on VKAs dose requirements in Slavic population from Central-Eastern Europe.

Very rare minor homozygous GG genotype of tissue factor +5466A>G mutation in a patient with two cryptogenic cerebrovascular ischemic events.

We identified a male Polish patient with a very rare minor homozygous GG genotype of the tissue factor (TF) +5466A>G polymorphism, who within two months experienced a transient ischemic attack (TIA) and ischemic stroke of unknown origin associated with the presence of patent foramen ovale below 40 years of age. A relationship between the TF +5466GG genotype and cerebrovascular thromboembolic events could be explained by detectable coagulant TF activity determined in a clotting assay and increased immunoreactive TF levels detected in plasma 5 years after the previous TIA and stroke. Given the role of TF-induced pathway in blood coagulation, it might be speculated that the TF +5466A>G polymorphism, especially in the homozygous GG form, predisposes to increased risk of cerebrovascular ischemic events. There is a need to conduct a prospective study on the effect of TF +5466A>G polymorphism on the risk of cryptogenic stroke.

[Optimalisation of treatment with vitamin K antagonists--the role of gene polymorphisms]. / Optymalizacja leczenia antagonistami witaminy K--rola polimorfizmów genowych.

The magnitude of a maintenance vitamin K antagonist (VKA) dose during anticoagulant therapy depends not only on clinical, environmental, and demographic factors, but also on genetic factors. Known genetic polymorphisms explain 40-50% of the variance in VKA dosing. Polymorphisms of two genes encoding enzymes involved in vitamin K and/or VKA metabolism such as vitamin K epoxide reductase complex subunit 1 (VKORC1) and cytochrome P450 2C9 isoform (CYP2C9) play a key role in this variance. Polymorphisms of cytochrome P450 4F2 isoform (CYP4F2), apolipoprotein E (APOE) and gamma-glutamyl carboxylase (GGCX) are of minor or negligible importance. In European populations, 3 haplotypes of VKORC1, VKORC1*2, VKORC1*3 and VKORC1*4--have been identified and they determined 99% of genetic variability of this enzyme. The presence of -1639G > A VKORC1 polymorphism is associated with increased VKA dose requirements. Allelic variants of CYP2C9*2 and CYP2C9*3 (found in 8-12% and 3-8% of individuals, respectively) increase the risk of haemorrhage due to slow VKA metabolism, especially at the therapy initiation. Pharmacogenetic algorithms incorporating VKORC1 and CYP2C9 genotypes help to predict the VKA dosage, particularly if the dose requirements are low or moderate. However, there is no compelling evidence showing reduced risk for clinical adverse events during VKA therapy following the identification of the patient's genetic profile.

The +405 GG variant of vascular endothelial growth factor polymorphism is associated with poor prognosis in patients undergoing coronary artery bypass graft surgery.

INTRODUCTION: Coronary artery bypass graft (CABG) surgery is associated with systemic response and increased concentrations of numerous cytokines. Vascular endothelial growth factor (VEGF) related pathway also seems to be involved in inflammatory response induced by CABG. OBJECTIVES: The aim of this study was to analyze the association between the VEGF gene +405 G>C polymorphism (linked to serum VEGF production), and the short-term clinical outcome during the in-hospital period (30 days) in patients undergoing CABG. PATIENTS AND METHODS: Genotyping for VEGF gene +405 G>C polymorphism was performed in 64 patients with coronary artery disease at a mean age of 66 years (76.6% males), with a mean EuroSCORE (European System for Cardiac Operative Risk Evaluation) of 2.5 (0-2 points: 50% patients, 3-4: 25%, > or =5 points: 25%), who underwent CABG surgery. RESULTS: Twenty-one (33%) patients were homozygous for the +405 G allele, 40 (63%) were heterozygous, and 3 were homozygous for the +405 C allele. Ten patients died during the 30-day follow-up (7 subjects with +405 GG genotype, and the other 3 carriers of the +405 C allele). Using multivariate logistic regression analysis, the risk of death after CABG was increased in patients with +405 GG genotype (odds ratio [OR] = 6.7; 95% confidence interval [CI] 1.5-29.4) and with EuroSCORE > or =5 points (OR = 4.4; 95% CI 1.1-18.1). CONCLUSIONS: The VEGF gene +405 G>C polymorphism might be a prognostic factor of an adverse postoperative course in patients undergoing CABG surgery. Apart from its proangiogenic action, VEGF may have additional, possibly proinflammatory properties.

FcepsilonRIalpha gene -18483A>C polymorphism affects transcriptional activity through YY1 binding.

Three frequent genetic polymorphisms in the human high-affinity IgE receptor alpha-subunit (FcepsilonRIalpha) were shown to be associated with allergic disorders and/or total serum IgE levels in allergic patients. Two of these were previously demonstrated to affect FcepsilonRIalpha expression while the third -18483A>C (rs2494262) has not yet been subjected to functional studies. We hypothesized that the -18483A>C variant affects transcriptional activity of the FcepsilonRIalpha distal promoter in monocytes in which FcepsilonRIalpha transcription is driven through that regulatory region. Indeed, we confirmed preferential binding of the YY1 transcription factor to the -18483C allele, resulting in lower transcriptional activity when compared with the -18483A allele.

Thrombin formation and platelet activation at the site of vascular injury in patients with coronary artery disease treated with clopidogrel combined with aspirin.

BACKGROUND: Data on the effects of oral antiplatelet agents on blood coagulation in vivo are conflicting. The platelet glycoprotein (GP) IIIa PlA2 allele has been suggested to modulate antithrombotic actions of clopidogrel. AIM: We investigated whether clopidogrel combined with aspirin affects local thrombin formation and platelet activation triggered by vascular injury. METHOD: We studied patients with stable coronary artery disease on chronic aspirin therapy randomised to addition of clopidogrel 75 mg/d (n = 30) or continuation of aspirin 100 mg/d (n = 30) for 4 weeks. Markers of thrombin generation [thrombin-antithrombin complexes (TAT) and prothrombin 1.2 fragments (F1.2)] and markers of platelet activation [soluble CD40 ligand (sCD40L) and P-selectin] were determined in the supernatant of blood samples obtained from a microvascular injury site. RESULTS: Total amounts of thrombin markers produced at the site of injury were similar before and after addition of clopidogrel, whereas platelet release of sCD40L and P-selectin was lower during treatment with aspirin + clopidogrel by 33.8% and 27.8% (p < 0.001), respectively. Patients in the highest tertile of reduction in platelet activation had previous myocardial infarction and peripheral arterial disease and released the highest amounts of sCD40L and P-selectin at baseline. TAT and F1.2 generation as well as sCD40L or P-selectin release were not influenced by the presence of the PlA2 allele. CONCLUSION: Our study shows that clopidogrel combined with aspirin does not reduce thrombin formation following vascular injury, but attenuates platelet sCD40L and P-selectin release.

[Factors influencing thrombin generation measured as thrombin-antithrombin complexes levels and using calibrated automated thrombogram in patients with advanced coronary artery disease]. / Czynniki wplywajace na generacje trombiny mierzona jako stezenie kompleksów trombina-antytrombina i metoda automatycznego skalibrowanego trombogramu u chorych z zaawansowana choroba wiencowa.

INTRODUCTION: Haemostatic factors play an important role in atherothrombosis. Thrombin generation is a crucial stage of blood coagulation. OBJECTIVES: Comparison of different thrombin generation markers: thrombin-antithrombin complex (TAT) generation and calibrated automated thrombogram method (CAT). Identification of factors influencing thrombin generation in patients with stable angina (SA) enrolled to the coronary artery bypass grafting (CABG) surgery. Analysis of traditional (age, gender, hypertension and diabetes) and novel (fibrinogen and C-reactive protein [CRP]) risk factors and the antiplatelet therapy (aspirin 75-150 mg/d) in relation to coagulation. PATIENTS AND METHODS: In 135 SA patients with left main coronary artery stenosis (> 50%) or major epicardial artery stenosis (> 70%), plasma TAT levels, maximal thrombin concentration (C(max)) and endogenous thrombin potential (ETP) were determined. A marker of the platelet activation (beta-thromboglobulin) was also measured. RESULTS: No correlations among TAT, C(max), ETP, risk factors and beta-thromboglobulin were observed. Linear regression model showed that independent predictors of TAT levels were age (beta = 0.5; p = < 0.0001), male gender and diabetes (beta = 0.36; p = 0.02). CRP independently predicted TAT and ETP (beta = -0.24 and beta = 0.22; p < 0.05, respectively), while fibrinogen predicted C(max) (beta = 0.21; p < 0.05). Independent predictors of beta-thromboglobulin were a male gender and aspirin use cessation (beta = 0.46; p = 0.01). Aspirin treatment had no effect on thrombin generation. CONCLUSIONS: Age, higher fibrinogen, CRP, diabetes and male gender influence thrombin generation and/or coagulation activation in SA patients. Plasma levels of thrombin-antithrombin complexes do not correlate with the parameters obtained using the calibrated automated thrombogram method (C(max), ETP).

[The thrombin generation is associated with the PIA1/A2 beta3, integrin polymorphism in aspirin-treated patients with coronary artery disease: a role of statins]. / Allel PIA1/A2 beta3 integryny wiaze sie ze zwiekszona generacja trombiny u pacjentów z choroba wiencowa leczonych kwasem acetylosalicylowym: wplyw leczenia statynami.

INTRODUCTION: The PIA2 allele is present in about 20-30% of European population. This allele has been associated with resistance to the antithrombotic action of aspirin in healthy PIA2 carriers. OBJECTIVES: To evaluate the functional association of the PIA1/A2 polymorphism of beta3 intergrins with increased thrombin generation and platelet activation in patients with coronary artery disease (CAD), treated with low-dose aspirin and whether the effect of this polymorphism is modulated by statin administration. PATIENTS AND METHODS: In 31 patients (25 M, 6 F) with CAD, aged 47 to 76 years, the thrombin-antithrombin complex generation (TAT) and the soluble form of CD40 ligand level (sCD40L) in blood collected every 60 seconds at sites of standardized microvascular injury were determined. RESULTS: Coronary angiography revealed > or = 1 major epicardial artery stenosis (> or = 50%) in all patients. Genotyping determined 18 subjects homozygous for PIA1 and 13 PIA2 heterozygous carriers. Homozygous PIA1 subjects exhibited increased fibrinogen levels compared with PIA2 carriers (4.2 [IQ 2.39] g/l vs. 2.5 [0.73] g/l, p <0.05). Maximal TAT level observed 6 min after microvascular injury was higher in PIA2 carriers (p = 0.01). Maximal sCD40L did not differ between PIA1/A1 subjects and PIA2 carriers. The PIA2 allele did not alter the velocity of TAT production and sCD40L release. The analysis of the area under the concentration vs. time curve for TAT revealed that PIA2 carriers exhibited increased thrombin generation compared with PIA1A1 subjects (by 17.5%, p <0.05). Subjects treated with statins (n = 12) had lower TAT generation and sCD40L release than non-treated (by 20%, p <0.005 and 23%, p <0.005, respectively). This effect was not altered by the PIA2 presence. CONCLUSIONS: In a model of microvascular injury the PIA1/A2 polymorphism influenced thrombin formation but not platelet activation in CAD patients treated with low-dose aspirin. The PIA2 allele did not alter the beneficial effect of statins on blood coagulation.

[Chlamydia pneumoniae infections--diagnostic methods]. / Zakazenia Chlamydia pneumoniae--metody diagnostyczne.

Gram-negative bacteria Chlamydia pneumonia was found in 1989 to cause acute and chronic respiratory tract infections. This agent has been as well associated with other disease: atherogenesis and coronary heart disease. This study is aimed both at making an introduction to the issues related to C. pneumoniae diagnosis and presenting contemporary laboratory methods. Given the limitations of traditional diagnostics methods, serodiagnosis (EIA) and nucleic acids amplification (PCR, hybridisation) provide the most convincing evidence of C. pneumoniae infections. Culture and direct fluorescence antibody (DFA) may be useful in confirming these results. A variety of methods applied can provide an opportunity to detect bacteria in different clinical samples--incl. sputum, nasopharyngeal and throat swabs, bronchoalveolar lavage (BAL) and tissues from biopsy and autopsy.