Nutri-pharmacogenomics of warfarin anticoagulation therapy: VKORC1 genotype-dependent influence of dietary vitamin K intake.

Warfarin is the most widely prescribed oral anticoagulant, but large interindividual variations exist in the dose required to achieve comparable therapeutic effects. Several clinical and genetic variables have been identified that influence warfarin dosing. However, interactions between genotype and nutrition remain uncertain in terms of dietary vitamin K intake. To investigate genotype-nutrient interactions in warfarin anticoagulation therapy, 202 consecutive outpatients (M/F = 142/60, mean age, 69 years) undergoing treatment with warfarin were enrolled. Prevalent single nucleotide polymorphisms in VKORC1 and CYP2C9 were genotyped, and dietary vitamin K intake during the week preceding the blood sampling was quantitatively estimated by a dietitian-assisted questionnaire. Patients were classified according to low, medium, or high vitamin K intake. The mean daily warfarin dose in subjects with a VKORC1-1639 A/A genotype was significantly smaller than that with a -1639A/G genotype (2.74 vs. 3.91 mg/day, respectively, p < 0.0001). Dose requirements did not differ between subjects with a CYP2C9 *1/*3 genotype versus a CYP2C9 *1/*1 genotype. In subjects with a variant VKORC1-1639 G allele, the mean daily warfarin dose was significantly attenuated by low vitamin K intake compared with medium and high intake after adjustment for covariates (3.4 vs. 5.0 vs. 4.0 mg/day, respectively, p = 0.028). No such genotype effects were observed in homozygous patients for the VKORC1-1639 A allele. The results of the present study suggest that the capacity of dietary vitamin K intake to influence warfarin dose requirements during anticoagulation therapy is VKORC1 genotype-dependent, at least in part.

Synthesis of 3,6-O-(o-xylylene)glucopyranosyl fluoride, an axial-rich glycosyl donor of ß-glycosylation.

Despite the reported complete ß-selectivity in glycosylation with 2,4-di-O-benzyl-3,6-O-(o-xylylene)glucopyranosyl fluoride, its preparation has been inefficient. This paper describes an improved route for the donor, including the formation of the 3,6-bridge on 1,2,4-orthoacetylglucose, the preparation of which was also refined, along with a discovered feature that the 3,6-bridged glucose prefers the furanose form. Although this feature made the synthesis of the desired glucopyranosyl donor difficult, application of thermal glycosylation solved the problem. With a modifiable intermediate, the improved availability of the donor would expand the applications.

Diurnal glycemic fluctuation is associated with severity of coronary artery disease in prediabetic patients: Possible role of nitrotyrosine and glyceraldehyde-derived advanced glycation end products.

BACKGROUND: Glucose fluctuation (GF) is a risk factor for coronary artery disease (CAD). However, it remains unknown whether specific indices of GF are risk factors for CAD. Therefore, we evaluated the relationship between GF, as determined by a continuous glucose monitoring system (CGMS) or the glucose level at 2h after a 75-g oral glucose tolerance test (75g OGTT 120), and the severity of CAD in prediabetic patients. We also evaluated whether nitrotyrosine (NT) and glyceraldehyde-derived advanced glycation end-products (Glycer-AGE) were induced by GF. METHODS: Twenty-eight prediabetic patients underwent coronary angiography (CAG), and the Gensini score and the SYNTAX score were evaluated as the severity of CAD, while the mean amplitude of glycemic excursions (MAGE) by CGMS and 75g OGTT 120 were evaluated. Serum NT and Glycer-AGE were measured. RESULTS: The MAGE was closely associated with the Gensini score (r=0.742, p<0.001) and the SYNTAX score (r=0.776, p<0.001), respectively. The 75g OGTT 120 was not associated with the Gensini score (r=0.36, p=0.06), but it was significantly associated with the SYNTAX score (r=0.413, p=0.036). Multiple linear regression analysis showed that the MAGE was the only independent determinant for the severity of CAD. The levels of NT and Glycer-AGE were significantly higher in the high MAGE group than in the low MAGE group. CONCLUSIONS: Diurnal GF is associated with the severity of CAD, even in prediabetic patients. GF, NT, and Glycer-AGE may play a pathological role in the progression of CAD.

A case of coronary rupture and pseudoaneurysm formation after fracture of implanted paclitaxel-eluting stents.

A 48-year-old man who had undergone implantation of two paclitaxel-eluting stents (PESs) at the right coronary artery was admitted to our hospital with progressive dyspnea. In the coronary care unit, he developed cardiogenic shock due to cardiac tamponade treated by pericardiocentesis. A coronary angiogram showed a large pseudoaneurysm at the site of the previously implanted stents, suggesting coronary rupture due to implanted stent fracture. The pseudoaneurysm was completely sealed by polytetrafluoroethylene-covered stent implantation. Although this case is very rare, coronary rupture by stent fracture should be considered when cardiac tamponade occurs after drug-eluting stent implantation, especially PES.

Chronic total occlusions of the right coronary and left anterior descending coronary arteries in a young adult patient with antiphospholipid syndrome.

A 36-year-old male appeared to have an old myocardial infarction on electrocardiogram, and coronary angiography (CAG) was performed. The CAG showed total occlusions of the right coronary artery and left anterior descending artery. He was successfully treated with drug-eluting stent implantation for both occluded coronary arteries. Such serious coronary lesions are uncommon for his young age. The patient was diagnosed as having antiphospholipid syndrome (APS) based on elevation of anticardiolipin antibody and anti-ß2 glycoprotein I antibody. Two years after stent implantation, the patient was well without ischemia or thrombosis. APS should be considered a potential cause of serious coronary disease in young adults. .

Increased levels of the oxidative stress marker, nitrotyrosine in patients with provocation test-induced coronary vasospasm.

BACKGROUND: Endothelial dysfunction of the coronary arteries caused by oxidative stress plays an important role in the pathogenesis of coronary vasospasm. However, it is not clear whether circulating biomarkers for oxidative stress are altered after coronary vasospasm. We investigated temporal changes in the levels of oxidative stress biomarkers after coronary vasospasm induced by intracoronary acetylcholine provocation testing, resulting in transient myocardial ischemia. METHODS AND RESULTS: Thirty consecutive patients with suspected vasospastic angina pectoris (VSAP) were enrolled in the study. Patients were categorized into the VSAP-positive group (n=14) and the VSAP-negative group (n=16) on the basis of test results. Serum samples were examined for the levels of the oxidative stress markers 4-hydroxynonenal (HNE) and nitrotyrosine (NT) before, and 15min, 3h, and 12h after the provocation test. The serum HNE levels did not change in either group after the test. The serum NT levels in the VSAP-positive group significantly increased at 3h and 12h after the test (11.3±3.3µg/ml at 3h, p=0.015, and 12.1±5.7µg/ml at 12h, p=0.03), as compared with baseline (8.1±3.2µg/ml). In the VSAP-negative group, the serum NT levels significantly decreased from baseline at each of the 3 time points. CONCLUSIONS: Serum NT significantly increased after coronary vasospasm induced by acetylcholine provocation, suggesting that serum NT could be a biomarker of transient myocardial ischemia and could contribute to the development of VSAP.

Serum deoxyribonuclease I activity can be a useful diagnostic marker for the early diagnosis of unstable angina pectoris or non-ST-segment elevation myocardial infarction.

BACKGROUND AND PURPOSE: Recently, serum deoxyribonuclease I (DNase I) activity has been highlighted as a potential diagnostic marker for transient myocardial ischemia. To evaluate whether serum DNase I activity can be a useful biomarker for diagnosing unstable angina pectoris (UAP) or non-ST-segment elevation myocardial infarction (NSTEMI), we investigated serial changes in DNase I levels after chest pain in UAP and NSTEMI (UAP/NSTEMI) patients. METHODS AND RESULTS: Thirty-three and ten patients classified into the UAP/NSTEMI and the chest pain syndrome (CPS) group, respectively, were enrolled. The serum DNase I activity levels within 3h after chest pain and the absolute median value of percentage differences in serum DNase I activity levels from admission to 3h after hospitalization in the UAP/NSTEMI patients was significantly higher than those in the CPS patients. We evaluated the patients to show positive results for DNase I activity if the serum levels or percentage differences exceeded the corresponding cut-off values. The sensitivity and specificity of DNase I within 6h after chest pain in the UAP/NSTEMI patients without elevated levels of cardiac troponin T and the MB isoenzyme of creatine kinase were 89% and 88%, respectively. CONCLUSIONS: Serum DNase I activity can be a useful marker for the early diagnosis of UAP/NSTEMI after the onset of chest pain, irrespective of the evidence of myocardial injury.

Place of pitavastatin in the statin armamentarium: promising evidence for a role in diabetes mellitus.

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, known as statins, have revolutionized the treatment of hypercholesterolemia and coronary artery disease prevention. However, there are considerable issues regarding statin safety and further development of residual risk control, particularly for diabetic and metabolic syndrome patients. Pitavastatin is a potent statin with low-density lipoprotein (LDL) cholesterol-lowering effects comparable to those of atorvastatin or rosuvastatin. Pitavastatin has a high-density lipoprotein (HDL) cholesterol raising effect, may improve insulin resistance, and has little influence on glucose metabolism. Considering these factors along with its unique pharmacokinetic properties, which suggest minimal drug-drug interaction, pitavastatin could provide an alternative treatment choice, especially in patients with glucose intolerance or diabetes mellitus. Many clinical trials are now underway to test the clinical efficacy of pitavastatin in various settings and are expected to provide further information.