CALR mutation burden in essential thrombocythemia and disease outcome.

ABSTRACT: Among 281 patients with essential thrombocythemia and calreticulin (CALR) mutation, we found a variant allele frequency of ≥60% to be associated with significantly shortened myelofibrosis-free survival, mostly apparent with CALR type-1 and CALR type-indeterminate mutations.

Relation of cytochrome P450 2C19 loss-of-function polymorphism to occurrence of drug-eluting coronary stent thrombosis.

Residual platelet reactivity (RPR) to adenosine 5' diphosphate (ADP) was an independent predictor of stent thrombosis (ST) in patients receiving drug-eluting stents on dual-antiplatelet treatment and was associated with the cytochrome P450 (CYP)2C19*2 polymorphism. The aim was to evaluate the role of the CYP2C19*2 polymorphism in the occurrence of ST or the composite end point of ST and cardiac mortality within a 6-month follow-up in patients undergoing percutaneous coronary interventions with drug-eluting stent implantation on dual-antiplatelet treatment enrolled in the RECLOSE trial. Seven hundred seventy-two patients were studied for the CYP2C19*2 polymorphism and RPR (using 10-muM ADP-induced platelet aggregation). Patients with ST or the composite of ST and cardiac mortality showed a higher prevalence of carriers of the rare allele (54.1% vs 31.3%; p = 0.025 and 51.7% vs 31.2%; p = 0.020, respectively). At multivariate logistic regression analysis with ST or ST and cardiac mortality as dependent variables and the CYP2C19*2 polymorphism, ADP RPR, and additional previously shown clinical and procedural risk factors for ST as independent variables, the CYP2C19*2 allele (ST odds ratio [OR] 3.43, 95% confidence interval [CI] 1.01 to 12.78, p = 0.047; ST and cardiac mortality OR 2.70, 95% CI 1.00 to 8.42, p = 0.049) and ADP RPR (ST OR 3.08, 95% CI 1.23 to 7.72, p = 0.016; ST and cardiac mortality OR 2.90, 95% CI 1.08 to 12.98, p = 0.019) were independent risk factors. Subjects with the contemporary presence of the CYP2C19*2 allele and ADP RPR showed a strong risk of ST or ST and cardiac mortality (OR 5.79, 95% CI 1.04 to 39.01, p = 0.033 and OR 11.45, 95% CI 1.84 to 71.27, p = 0.009, respectively). In conclusion, the CYP2C19*2 allele was associated with the occurrence of ST or ST and cardiac mortality in high-risk vascular patients on dual-antiplatelet treatment. These findings could impact on the future design of pharmacogenetic antiaggregant strategies.

Cytochrome P450 2C19 loss-of-function polymorphism, but not CYP3A4 IVS10 + 12G/A and P2Y12 T744C polymorphisms, is associated with response variability to dual antiplatelet treatment in high-risk vascular patients.

OBJECTIVES: The aim of this study was to evaluate the effect of polymorphisms affecting the clopidogrel metabolism (CYP3A4 IVS10+12G/A and CYP2C19*2) and the P2Y12 receptor (P2Y12 T744C) on modulating platelet function in acute coronary syndrome patients on dual antiplatelet treatment. BACKGROUND: Residual platelet reactivity (RPR) phenomenon on antiplatelet therapy requires clarification. P2Y12 T744C, CYP3A4 IVS10+12G/A and, in healthy individuals only, CYP2C19*2 polymorphisms have been investigated; however, the influence on platelet reactivity in a large population of high-risk vascular patients on dual antiplatelet treatment has not yet been elucidated. METHODS: A total of 1419 acute coronary syndrome patients on dual antiplatelet treatment were studied. Platelet function was evaluated by platelet-rich plasma aggregation. Electronic nanochips and restriction-fragment length polymorphism were used for analysis of polymorphisms. RESULTS: Only CYP2C19*2, out of the three investigated polymorphisms, is associated with higher platelet reactivity. Carriers of the *2 allele had significantly higher platelet aggregation values after arachidonic acid (AA; P=0.043), 2 micromol/l adenosine 5' diphosphate (ADP; P<0.0001) and 10 micromol/l ADP (P=0.001) stimuli. The genotype distribution of CYP2C19*2 polymorphism significantly differed between patients with and without RPR, as evaluated by 10-micromol/l ADP-induced platelet aggregation (P=0.002) and by AA-induced platelet aggregation (P=0.045). At the multivariate linear regression analysis, the CYP2C19*2 polymorphism remained a significant and independent risk factor for dual antiplatelet treatment variability. CONCLUSIONS: This study demonstrates, for the first time, that the *2 CYP2C19 allele is associated with higher platelet aggregability and RPR in high-risk vascular patients on dual antiplatelet treatment. These findings can have a significant impact on the future design of pharmacogenetic antiaggregant strategies for high-risk vascular patients on dual antiplatelet treatment.

Predictors of vitamin B6 and folate concentrations in older persons: the InCHIANTI study.

BACKGROUND: Low dietary intake and low serum concentrations of vitamin B6 and/or folate are associated with increased risk of vascular events, possibly because of their association with inflammation, which plays a crucial role in the pathogenesis of cardiovascular diseases. METHODS: Using data from 1320 participants in the population-based InCHIANTI study (586 men and 734 women; median age, 69 years; range, 21-102 years) for whom complete data on folate, vitamin B6, inflammatory markers, 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T sequence variant, and important covariates were available, we evaluated the association of inflammatory markers with circulating concentrations of vitamin B6 and folate, independently of dietary vitamin intake, circulating vitamin concentrations, and MTHFR C677T sequence variant. RESULTS: According to multiple linear regression analysis, C-reactive protein and interleukin-6 receptor were strongly and negatively associated with circulating vitamin B6 but not with folate concentrations, independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, dietary nutrient intake, and circulating homocysteine and vitamin concentrations. Serum folate concentrations were related to MTHFR 677 TT genotype in persons with folate intake in the lowest tertile (< 221.2 microg/day). Vitamin C and retinol intakes were strongly and positively associated with serum folate concentrations independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, homocysteine plasma concentrations, dietary nutrient intakes, serum vitamin B6 and vitamin B12 concentrations, and MTHFR C677T sequence variant. CONCLUSIONS: Low serum vitamin B6, but not serum folate, concentrations are independent correlates of the proinflammatory state, and both are influenced by antioxidant reserves.

eNOS G894T polymorphism as a mild predisposing factor for abdominal aortic aneurysm.

OBJECTIVE: Abdominal aortic aneurysm (AAA) represents a chronic degenerative condition associated with atherosclerosis. Actually, data from experimental and clinical studies suggest that nitric oxide (NO) is a modulator in maintaining endothelial function and antithrombotic intravascular environment. Reduced vascular NO generation in subjects carrying the rare variants of the eNOS gene might predispose to AAA. No information is available about the influence of the eNOS gene T-786C, G894T, and 4a/4b polymorphisms in the susceptibility to the disease. METHODS: In this study, we evaluated the role of these polymorphisms in the predisposition to AAA and their influence in hypertensive and normotensive patients. We studied 250 consecutive patients with AAA referred to the Unit of Vascular Surgery of the University of Florence compared with 250 truly healthy subjects with a negative history of vascular diseases. All subjects, patients, and controls, underwent duplex scanning examination, and to assess the presence of other atherosclerotic localizations, all patients underwent clinical and instrumental examinations. RESULTS: A significant difference in genotype distribution and allele frequency was observed for eNOS G894T but not for T-786C and 4a/4b polymorphisms. At the multivariate analysis after adjustment for traditional vascular risk factors and other atherosclerotic localizations, the eNOS 894T variant was significantly associated with AAA, according to dominant and recessive models (dominant model odds ratio [OR]: 2.2, 95% confidence interval [CI]: 1.21-3.93, P = .007; recessive model OR: 2.7, 95% CI: 1.42-5.20, P = .002). When patients with other atherosclerotic localizations were excluded from the analysis, the 894T variant still remained associated with the predisposition to AAA, according to the models considered (dominant model OR: 2.1, 95%CI: 1.23-3.92, P = .007; recessive model OR: 2.8, 95%CI: 1.45-5.24, P = .002). CONCLUSIONS: The present study showed that the eNOS G894T polymorphism is a mild modulator of the predisposition to AAA apart from traditional risk factors, suggesting a genetic influence on the molecular mechanisms responsible for this complex disease.

Low protein Z plasma levels are independently associated with acute coronary syndromes.

Protein Z (PZ) is a single chain vitamin-K-dependent glycoprotein synthesized by the liver. Studies in vivo and in vitro suggest that PZ plays an important role in inhibiting coagulation as it serves as cofactor for the inactivation of factor Xa by forming a complex with the plasma PZ-dependent protease inhibitor. Recently, conflicting findings on plasma PZ levels in patients with ischemic stroke have been published. Aim of our study was to investigate the role of PZ in acute coronary syndromes (ACS). PZ plasma levels were determined in 223 (189 M; 34 F) patients with ACS referring to the Coronary Intensive Therapy Unit of University of Florence and in 265 (219 M; 46 F) healthy subjects. Patients under oral anticoagulation treatment as well as subjects with positivity for antiphospholipid antibodies were excluded. None had liver or kidney dysfunction. The mean PZ plasma level was lower in patients (1508 +/- 730 ng/mL) than in controls (1728 +/- 594 ng/mL) (p < 0.0001). PZ levels below the 5th percentile (565 ng/mL) of normal values distribution in control subjects were found in 15.7% of patients and in 4.9% of controls (p <0.0001). At multivariate analysis, PZ levels below 565 ng/mL were associated with ACS (OR=3.3; 99%CI 1.1-9.7; p = 0.004). The contemporary presence of low PZ levels and smoking habit leads to an increased risk of ACS (OR=9.5; 99%CI 2.4-37.2; p < 0.0001). In conclusion, our results suggest a possible role of PZ in the occurrence of arterial thrombosis.