Autosomal dominant polycystic kidney disease (ADPKD) is due to mutations in genes PKD1 and PKD2 encoding polycystin-1 and -2, which transduce flow variations into cellular signals in the renal epithelium but also in vascular endothelium. However, the impact of polycystin deficiency on the release of endothelium-derived factors during flow variations is unknown. In 21 normotensive ADPKD patients with normal kidney function and 21 control subjects, radial artery diameter and blood flow were measured during hand skin heating and post-ischemic hyperaemia. Local blood samples were drawn during heating to quantify plasma nitrite, indicator of nitric oxide (NO) availability, epoxyeicosatrienoic acids (EETs) and endothelin-1. Basal inflammatory and oxidative stress markers were similar between groups. Flow-mediated dilatation was lower in ADPKD patients than in controls during heating (16.1±1.1 vs. 23.2±1.0

<正>研究人员试图运用功能和生物学方法确定环氧花生四烯酸、一氧化氮/活性氧平衡及内皮素1在原发性高血压患者传导性动脉内皮功能紊乱中所起的作用。方法与结果:研究对象为未经治疗的原发性高血压患者28例和正常血压者30名,测定其由于手部皮肤加

The mechanisms involved in the endothelial dysfunction of conduit arteries, which is an independent contributor to the high incidence of cardiovascular events during essential hypertension, remains to be fully elucidated. Radial artery diameter, blood flow and mean wall shear stress were determined in 28 non-treated essential hypertensive patients and 30 normotensive control subjects, during endothelium-dependent flow-mediated dilatation (FMD) induced by hand skin heating. The role of epoxyeico-satrienoic acids (EETs) and NO was assessed during heating using the brachial infusion of inhibitors of cytochrome P450 epoxygenases (fluconazole) and NO-synthase (L-NMMA). First, as compared with controls, hypertensive patients exhibited a decreased FMD in response to post-ischemic hyperemia as well as to heating, as shown by the lesser slope of their diameter-shear stress relationship, with no modification in endothelium-independent dilatation. In controls, heating-induced FMD was reduced by fluconazole, L-NMMA and, to a larger extent, by L-NMMA+fluconazole. In patients, FMD was not affected by fluconazole and was reduced by L-NMMA and L-NMMA+fluconazole to a lesser extent than in controls. Local plasma EETs level increased during heating in controls (an effect diminished by fluconazole), but not in patients. Plasma nitrite level, an indicator of NO availability, increased during heating in controls (an effect abolished by L-NMMA), and to a lesser extent in patients. Plasma endothelin-1 level decreased during heating in controls but not in patients. These results show that an impaired role of EETs contributes with alteration in NO and endothelin-1 pathways to conduit artery endothelial dysfunction in essential hypertension.

Background— We sought to clarify, using functional and biological approaches, the role of epoxyeicosatrienoic acids, nitric oxide (NO)/reactive oxygen species balance, and endothelin-1 in conduit artery endothelial dysfunction during essential hypertension. Methods and Results— Radial artery diameter and mean wall shear stress were determined in 28 untreated patients with essential hypertension and 30 normotensive control subjects during endothelium-dependent flow-mediated dilatation induced by hand skin heating. The role of epoxyeicosatrienoic acids and NO was assessed with the brachial infusion of inhibitors of cytochrome P450 epoxygenases (fluconazole) and NO synthase ( N G -monomethyl- l -arginine [L-NMMA]). Compared with controls, hypertensive patients exhibited a decreased flow-mediated dilatation in response to postischemic hyperemia as well as to heating, as shown by the lesser slope of their diameter–shear stress relationship. In controls, heating-induced flow-mediated dilatation was reduced by fluconazole, L-NMMA, and, to a larger extent, by L-NMMA+fluconazole. In patients, flow-mediated dilatation was not affected by fluconazole and was reduced by L-NMMA and L-NMMA+fluconazole to a lesser extent than in controls. Furthermore, local plasma epoxyeicosatrienoic acids increased during heating in controls (an effect diminished by fluconazole) but not in patients. Plasma nitrite, an indicator of NO availability, increased during heating in controls (an effect abolished by L-NMMA) and, to a lesser extent, in patients, whereas, inversely, reactive oxygen species increased more in patients (an effect diminished by L-NMMA). Plasma endothelin-1 decreased during heating in controls but not in patients. Conclusions— These results show that an impaired role of epoxyeicosatrienoic acids contributes, together with an alteration in NO/reactive oxygen species balance and endothelin-1 pathway, to conduit artery endothelial dysfunction in essential hypertension. Clinical Trial Registration— https://www.eudract.ema.europa.eu . Unique identifier: RCB2007-A001–10-53.

Chlormethiazole is a sedative and anticonvulsive drug used in the treatment of alcohol withdrawal. Because it had been reported that chlormethiazole inhibits the alcohol-inducible cytochrome P450 2E1 in rat liver, we investigated the in vivo and in vitro effect of this drug on cytochrome P450 2E1 in human beings. The activity of this cytochrome was assessed using chlorzoxazone as a probe. The 6-hydroxychlorzoxazone- chlorzoxazone blood concentration ratio, reflecting the cytochrome P450 2E1 activity, was determined in 10 controls and in 24 alcoholic patients who had entered a hospital for detoxification. Alcoholic patients were administered either chlormethiazole (1.3-2.3 g/d) or chlorazepate (100-300 mg/d) as a sedative. Cytochrome P450 2E1 activity was significantly increased in alcoholic patients treated with chlorazepate (1.16 ± 0.40 vs. 0.27 ± 0.03, P < .05). In contrast, chlormethiazole treatment inhibited chlorzoxazone hydroxylation almost totally (0.046 ± 0.03, P < .001). After 7-14 days of ethanol withdrawal, alcoholic patients treated with chlorazepate had ratio values similar to those of controls (0.31 ± 0.05), whereas values from alcoholic patients treated with chlormethiazole remained low (0.049 ± 0.01) even though chlormethiazole doses were gradually decreased. Pharmacokinetic studies in controls showed that chlormethiazole-mediated inhibition was present even when chlormethiazole was not detectable in the blood. In addition, the effect of chlormethiazole on cytochrome P450 2E1 was studied in vitro using human liver microsomes. Dixon plot analyses showed a noncompetitive inhibition (Ki = 12 µmol/L). These data clearly show that chlormethiazole is an efficient inhibitor of chlorzoxazone metabolism and thus of cytochrome P450 2E1 activity in human beings. Because cytochrome P450 2E1 induction after chronic ethanol consumption has detrimental effects on the liver through free radical formation, treatment of alcohol detoxification with chlormethiazole may be beneficial.

A simple and sensitive method is proposed for the measurement of acetaldehyde in human blood. Venous blood samples were collected in EDTA Vacutainer tubes, and treated immediately with 0.6 M ice-cold perchloric acid in saline. After centrifugation at 4°C, the supernatants were treated with dinitrophenylhydrazine reagent. After addition of the internal standard (crotonaldehyde dinitrophenylhydrazone) and 3 M sodium acetate, the derivatives were extracted and analysed by high-performance liquid chromatography (HPLC) using an Ultrasphere ODS column. The compounds were separated using acetonitrile—water as the mobile phase and detected at 356 nm. A blank determination was carried out for each analysis and subtracted from the results. The specificity of the method was tested by UV and mass spectrometry and the purity of the derivatives by capillary gas chromatography. The recovery of blood acetaldehyde was 98%. Interference from ethanol was minimized by using the tripotassium salt of EDTA as an anticoagulant. The sensitivity of the method can be increased dramatically using microbore HPLC. The level of acetaldehyde was found to be 0.41 ± 0.13 μM (mean ± S.D.) for eight fasting controls and 0.91 ± 0.73 μM for fourteen alcoholics (p<0.05). At 30 min after oral administration of ethanol (0.8 g/kg), the ethanol levels were 16.3 ± 2.8 and 17.7 ± 2.5 mM and the acetaldehyde levels were 1.67 ± 0.35 and 3.13 ± 2.43 μM (p<0.05) for the controls and alcoholics, respectively.

The in vitro effects of acetaldehyde treatment on the binding of phenytoin and diazepam to human serum albumin (HSA) and human serum proteins (HSP) have been investigated. The incorporation of acetaldehyde into proteins following incubation with different concentrations of [1,2-14 C]-acetaldehyde (0.5, 25, 100 mmol/l) was carried out. The proteins were then dialyzed so that only the stable adduct was retained. Binding of phenytoin and diazepam was then studied. Scatchard plot analysis showed a slight decrease (p less than 0.01 for HSP and 25 mmol/l acetaldehyde) in the number of binding sites for phenytoin when the acetaldehyde/protein ratio was increased. The affinity constant was also increased (p less than 0.01) with 100 mmol/l acetaldehyde. No change could be demonstrated in the number of diazepam binding sites on HSA; an increase in the binding capacity of HSP was shown following incubation with 25 mmol/l acetaldehyde. The fraction of drug bound at therapeutic levels has been also calculated for both drugs. An increase for diazepam but no change for phenytoin can be observed before or after treatment of proteins with acetaldehyde.