Warfarin, a commonly prescribed anticoagulant, exhibited large inter-individual and inter-ethnic differences in the dose required for its anticoagulation effect. Asian populations, including Chinese, require a much lower maintenance dose than Caucasians, for which the mechanisms still remain unknown. We determined DNA sequence variants in CYP2C9 and VKORC1 in 16 Chinese patients having warfarin sensitivity (< or = 1.5 mg/day, n = 11) or resistance (> or = 6.0 mg/day, n = 5), 104 randomly selected Chinese patients receiving warfarin, 95 normal Chinese controls and 92 normal Caucasians. We identified three CYP2C9 variants, CYP2C9*3, T299A and P382L, in four warfarin-sensitive patients. A novel VKORC1 promoter polymorphism (-1639 G > A) presented in the homozygous form (genotype AA) was found in all warfarin-sensitive patients. The resistant patients were either AG or GG. Among the 104 randomly selected Chinese patients receiving warfarin, AA genotype also had lower dose than the AG/GG genotype (P < 0.0001). Frequencies of AA, AG and GG genotypes were comparable in Chinese patients receiving warfarin (79.7, 17.6 and 2.7%) and normal Chinese controls (82, 18 and 0%), but differed significantly from Caucasians (14, 47 and 39%) (P < 0.0001). The promoter polymorphism abolished the E-box consensus sequences and dual luciferase assay revealed that VOKRC1 promoter with the G allele had a 44% increase of activity when compared with the A allele. The differences in allele frequencies of A/G allele and its levels of VKORC1 promoter activity may underscore the inter-individual differences in warfarin dosage as well as inter-ethnic differences between Chinese and Caucasians.

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Abstract-Resveratrol is a phytoestrogen naturally found in grapes and is among the major constituents of wine thought to have a cardioprotective effect. Endothelin-1 (ET-1) is a potent vasopressor synthesized by endothelial cells both in culture and in vivo. The aims of this study were to test the hypothesis that resveratrol may alter strain-induced ET-1 gene expression and to identify the putative underlying signaling pathways in endothelial cells. We show that resveratrol indeed potently inhibits strain-induced ET-1 secretion, ET-1 mRNA level, and ET-1 promoter activity. Resveratrol also inhibits strain-increased NADPH oxidase activity, reactive oxygen species formation, and extracellular signal-regulated kinases1/2 (ERK1/2) phosphorylation. Furthermore, pretreating cells with resveratrol or antioxidant N-acetyl-cysteine decreases strain-increased or hydrogen peroxide-increased ET-1 secretion, ET-1 promoter activity, and ET-1 mRNA and ERK1/2 phosphorylation. Using both the electrophoretic mobility shift assay and a reporter gene assay, resveratrol and N-acetyl-cysteine also attenuated the strain-stimulated activator protein-1 binding activity and activator protein-1 reporter activity. In summary, we demonstrate for the first time that resveratrol inhibits strain-induced ET-1 gene expression, partially by interfering with the ERK1/2 pathway through attenuation of reactive oxygen species formation. Thus, this study provides important new insights in the molecular pathways that may contribute to the proposed beneficial effects of resveratrol in the cardiovascular system. any epidemiological studies show a correlation between a low incidence of coronary heart disease and atherosclerosis and a moderate consumption of red wine. 1,2 The vasoprotective effect of red wine, also known as the "French paradox," is currently best exemplified by transresveratrol (trans-3,5,4Ј-hydroxystilbene). 3,4 Resveratrol has many biological activities, including protection from or reduction of the incidence of coronary heart disease. Resveratrol also has been found to protect the heart from ischemiareperfusion injury. 5 Antioxidant properties of resveratrol appear to be partly responsible for this activity. 5-9 Moreover, resveratrol was shown to relax aortic rings in rats through an endothelium-mediated enhancement of the nitric oxide (NO)-cGMP cascade. 10 Subsequent pharmacological studies indicate a direct relaxant effect of resveratrol on vascular smooth muscle that may exert beneficial effects in cardiovascular disease, though the mechanism of these effects is no known. 11 Recently, Orallo et al 12 demonstrated that the characteristic endothelium-dependent vasorelaxant effect of resveratrol in the rat aorta appeared to be caused by the inhibition of vascular NADH/NADPH oxidase and the subsequent decrease in the generation of basal cellular superoxide anions and, therefore, of NO biotransformation. However, little is known about the cellular/molecular mechanisms whereby resveratrol could protect against coronary heart disease. Indee...

No abstract

Polymorphisms in the VKORC1 gene have the strongest effects on warfarin dose, followed by CYP2C9*3. In addition, our results showed that CYP2C18, PROC and EPHX1 have small but significant associations with warfarin dose. In multiple regression analysis, PROC and EPHX1 explained 3% of the dose variation. The incorporation of these two genes into warfarin dosing algorithms could improve the accuracy of prediction in the Han-Chinese population.

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Intracellular pH (pH(i)) exerts considerable influence on cardiac contractility and rhythm. Over the last few years, extensive progress has been made in understanding the system that controls pH(i) in animal cardiomyocytes. In addition to the housekeeping Na(+)-H(+) exchanger (NHE), the Na(+)-HCO(3)(-) symporter (NHS) has been demonstrated in animal cardiomyocytes as another acid extruder. However, whether the NHE and NHS functions exist in human atrial cardiomyocytes remains unclear. We therefore investigated the mechanism of pH(i) recovery from intracellular acidosis (induced by NH(4)Cl prepulse) using intracellular 2',7'-bis(2-carboxethyl)-5(6)-carboxy-fluorescein fluorescence in human atrial myocardium. In HEPES (nominally HCO(3)(-)-free) Tyrode solution, pH(i) recovery from induced intracellular acidosis could be blocked completely by 30 microM 3-methylsulfonyl-4-piperidinobenzoyl, guanidine hydrochloride (HOE 694), a specific NHE inhibitor, or by removing extracellular Na(+). In 3% CO(2)-HCO(3)(-) Tyrode solution, HOE 694 only slowed the pH(i) recovery, while addition of HOE 694 together with 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (an NHS inhibitor) or removal of extracellular Na(+) inhibited the acid extrusion entirely. Therefore, in the present study, we provided evidence that two acid extruders involved in acid extrusion in human atrial myocytes, one which is HCO(3)(-) independent and one which is HCO(3)(-) dependent, are mostly likely NHE and NHS, respectively. When we checked the percentage of contribution of these two carriers to pH(i) recovery following induced acidosis, we found that the activity of NHE increased steeply in the acid direction, while that of NHS did not change. Our present data indicate for the first time that two acid extruders, NHE and NHS, exist functionally and pH(i) dependently in human atrial cardiomyocytes.

Activating transcription factor 3 (ATF3), a cAMP response element-binding protein/ATF family transcription factors member, has been implicated in the cardiovascular and inflammatory system and is rapidly induced by ischemic-reperfusion injuries. We performed transverse aortic banding (TAB) experiments using ATF3 gene-deleted mice (ATF3 2/2 ) and wild-type (WT) mice to determine what effect it might have on heart failure induced by pressure overloading. Compared with the WT mice, ATF3 2/2 mice were found by echocardiography to have decreased left ventricular contractility with loss of normal cardiac hypertrophic remodeling. The ATF3 2/2 mice had greater numbers of terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling-positive cells and higher levels of activated caspase-3, as well as more apoptosis. Restoration of ATF3 expression in the heart of ATF3 2/2 mice by adenovirus-induced ATF3 treatment significantly improved cardiac contractility after TAB. The results from molecular and biochemical analyses, including chromatin immune-precipitation and in vitro /in vivo promoter assays, showed that ATF3 bound to the ATF/cAMP response element of the Beclin-1 promoter and that ATF3 reduced autophagy via suppression of the Beclin-1-dependent pathway. Furthermore, infusion of tert-butylhydroquinone (tBHQ), a selective ATF3 inducer, increased the expression of ATF3 via the nuclear factor erythroid 2-related transcriptional factor, inhibited TABinduced cardiac dilatation, and increased left ventricular contractility, thereby rescuing heart failure. Our study identified a new epigenetic regulation mediated by the stress-inducible gene ATF3 on TAB-induced cardiac dysfunction. These findings suggest that the ATF3 activator tBHQ may have therapeutic potential for the treatment of pressure-overload heart failure induced by chronic hypertension or other pressure overload mechanisms.