Epicardial coronary artery constriction with intravenous ethanol

Climatic and soil factors explain the two-dimensional spectrum of global plant trait variation

Plant functional traits can predict community assembly and ecosystem functioning and are thus widely used in global models of vegetation dynamics and land-climate feedbacks. Still, we lack a global understanding of how land and climate affect plant traits. A previous global analysis of six traits observed two main axes of variation: (1) size variation at the organ and plant level and (2) leaf economics balancing leaf persistence against plant growth potential. The orthogonality of these two axes suggests they are differently influenced by environmental drivers. We find that these axes persist in a global dataset of 17 traits across more than 20,000 species. We find a dominant joint effect of climate and soil on trait variation. Additional independent climate effects are also observed across most traits, whereas independent soil effects are almost exclusively observed for economics traits. Variation in size traits correlates well with a latitudinal gradient related to water or energy limitation. In contrast, variation in economics traits is better explained by interactions of climate with soil fertility. These findings have the potential to improve our understanding of biodiversity patterns and our predictions of climate change impacts on biogeochemical cycles.

Alcohol consumption may not affect the diameter of the coronary arteries in men with chest pain

Objective

The effect of alcohol consumption on the risk of coronary heart disease is controversial. Several studies have assessed the effects of alcohol on the formation of atherosclerotic plaques, but few studies have evaluated the chronic effects of alcohol consumption on the coronary artery diameter. We investigated whether alcohol consumption affects the coronary artery diameter.

Methods

This prospective study enrolled men who were undergoing coronary angiography at the First Affiliated Hospital of Chongqing Medical University from November 2016 to December 2017. The participants were categorized into three groups based on their drinking behavior: heavy drinking (>175 g/week in the last 2 years, n = 70), moderate drinking (>42 to ≤175 g/week in the last 2 years, n = 53), and nondrinking (lifetime alcohol consumption of <98 g, n = 79). The diameters of the left and right coronary arteries were compared among the three groups.

Results

No significant differences in the diameters of the left and right coronary arteries were observed among the three groups.

Conclusions

Alcohol consumption may not affect the diameter of the coronary arteries.

Ethanol enhances endothelial ionic currents and nitric oxide release via intermediate-conductance calcium-activated potassium channel

AIMS

Ethanol is known to induce NO release and coronary vasorelaxation. Evidence suggests that K⁺ channels, especially a Ca²⁺-activated K⁺ channel (K_Ca), may regulate endothelial NO production. We aimed to investigate the ethanol effect on K⁺ currents in human coronary artery endothelial cells (HCAECs), identify the K⁺ channel type/subtype and signaling pathway involved, and demonstrate the relevance to ethanol-induced NO release.

MAIN METHODS

Ionic currents of cultured HCAECs were studied using whole-cell patch clamp technique. NO production were measured using the fluorescent probe, 2,3-diaminonaphthalene.

KEY FINDINGS

We found that ethanol significantly potentiated HCAEC current (maximal increase to 155.68 ± 18.93%, 20 mM ethanol, +80 mV; mean ± SEM, n = 9). Ethanol-induced current was significantly inhibited by blockers of IK_Ca or SK_Ca (intermediate- or small-conductance K_Ca), but not by blocking other K⁺ channels. When other known HCAEC channels were inhibited except IK_Ca, 20 mM ethanol significantly increased IK_Ca current to 198 ± 25.11% (n = 6), but it could not enhance SK_Ca current that was similarly isolated. Moreover, ethanol-induced NO release was prevented by blocking IK_Ca channel, adenosine A_2A receptor (A_2AR), G_s protein, or protein kinase A (PKA).

SIGNIFICANCE

This study was the first to demonstrate that acute ethanol exposure could activate endothelial IK_Ca channel, via A_2AR-G_s-PKA signaling, leading to increased whole-cell current and NO release, which could be an important mechanism underlying ethanol-induced NO release and vasodilation.

Effects of ethanol on the tonicity of corporal tissue and the intracellular Ca2+ concentration of human corporal smooth muscle cells

Heavy alcohol consumption is associated with an increased risk of erectile dysfunction (ED); however, the acute effects of ethanol (EtOH) on penile tissue are not fully understood. We sought to investigate the effects of EtOH on corporal tissue tonicity, as well as the intracellular Ca(2+) concentration ([Ca(2+)](i)) and potassium channel activity of corporal smooth muscle. Strips of corpus cavernosum (CC) from rabbits were mounted in organ baths for isometric tension studies. Electrical field stimulation (EFS) was applied to strips precontracted with 10 μmol L(-1) phenylephrine as a control. EtOH was then added to the organ bath and incubated before EFS. The [Ca(2+)](i) levels were monitored by the ratio of fura-2 fluorescence intensities using the fura-2 loading method. Single-channel and whole-cell currents were recorded by the conventional patch-clamp technique in short-term cultured smooth muscle cells from human CC tissue. The corpus cavernosal relaxant response of EFS was decreased in proportion to the concentration of EtOH. EtOH induced a sustained increase in [Ca(2+)](i) in a dose-dependent manner, Extracellular application of EtOH significantly increased whole-cell K(+) currents in a concentration-dependent manner (P < 0.05). EtOH also increased the open probability in cell-attached patches; however, in inside-out patches, the application of EtOH to the intracellular aspect of the patches induced slight inhibition of Ca(2+)-activated potassium channel (KCa) activity. EtOH caused a dose-dependent increase in cavernosal tension by alterations to [Ca(2+)](i). Although EtOH did not affect KCa channels directly, it increased the channel activity by increasing [Ca(2+)](i). The increased corpus cavernosal tone caused by EtOH might be one of the mechanisms of ED after heavy drinking.

Cocaine and ethanol: combined effects on coronary artery blood flow and myocardial function in dogs

OBJECTIVES

In combination, cocaine and ethanol are more cardiotoxic than is either substance alone. These substances together constitute a drug abuse combination that commonly results in fatality. Previously the authors have demonstrated that cardiotoxicity of cocaine and ethanol is in part due to synergistic myocardial-depressant effects. However, it remains unclear whether this myocardial depression is associated with concomitant adverse effects on coronary blood flow in relation to these substances. The aim of this study was to investigate combined effects of cocaine and ethanol on myocardial blood flow, in relation to indices of myocardial function.

METHODS

Anesthetized dogs were instrumented for hemodynamic monitoring with Doppler flow probes placed on the circumflex and left anterior descending (LAD) coronary arteries. Dogs were randomized to three groups (each n = 6): ethanol (E, 1.5 g/kg followed by placebo), cocaine (C, placebo followed by cocaine, 7.5 mg/kg IV), or cocaine plus ethanol (C + E). All measurements were made at control, after placebo or ethanol, and then at fixed time intervals after cocaine or placebo bolus over 3 hours.

RESULTS

In both the C + E and the C groups, circumflex blood flow (CBF) decreased by 71% (95% confidence interval [CI] = 56% to 85%) and 57% (95% CI = 43% to 72%, both p < 0.04 vs. baseline) immediately after cocaine bolus. This was associated with transient depression of cardiac output, myocardial contractile function, and rate-pressure product (RPP), all indices of myocardial oxygen demand. A subsequent rebound increase of coronary sinus blood flow (CSBF) of 56% (95% CI = 26% to 137%, p < 0.03) compared to baseline occurred only in the C group and was associated with increases of myocardial contractile function and RPP. In the C + E group, 2 hours after drug administration, there was a decrease in CSBF of 49% (95% CI = 32% to 67%; p < 0.01) compared to baseline, which was associated with concomitant numerical decreases of the indices of myocardial oxygen demand and accumulation of cocaethylene.

CONCLUSIONS

Acute decreases in myocardial flow secondary to cocaine, and cocaine and ethanol in combination, were similar and temporally associated with cocaine's direct myocardial-depressant effects. Rebound increases in myocardial function and blood flow due to cocaine were attenuated by ethanol. Delayed myocardial depression and decreases in myocardial blood flow were observed only with coadministration of cocaine and ethanol.

Binge drinking and mortality after acute myocardial infarction

BACKGROUND

Moderate drinkers have a lower risk of mortality after myocardial infarction (MI). Although binge drinking has been associated with a higher risk of MI in some studies, its relation to prognosis after MI is uncertain.

METHODS AND RESULTS

In a prospective, inception cohort study conducted at 45 US hospitals, 1935 patients hospitalized with a confirmed MI between 1989 and 1994 underwent detailed personal interviews. Patients reported their usual frequency of binge drinking of beer, wine, and liquor, defined as intake of 3 or more drinks within 1 to 2 hours, and were followed up for mortality for a median of 3.8 years. Of 1919 eligible patients, 250 (94% men) reported binge drinking during the prior year, and a total of 318 patients died during follow-up. Binge drinkers had a 2-fold higher risk of mortality than drinkers who did not binge (hazard ratio, 2.0; 95% confidence interval, 1.3 to 3.0). A comparison of 192 binge drinkers and 192 other patients matched on propensity scores yielded a similar result. The association between binge drinking and total mortality tended to be similar among patients whose usual alcohol intake was light or heavier and for binge drinkers who consumed beer, wine, or liquor. Usual alcohol intake was inversely associated with mortality, but binge drinking completely attenuated this relation.

CONCLUSIONS

Our results suggest that alcohol consumption may be linked to potential hazards among patients who survive acute MI. Although moderate intake has been associated with lower mortality, binge drinking, even among light drinkers, appears to be associated with 2-fold higher mortality.

Effects of red wine, alcohol, and quercetin on coronary resistance and conductance arteries

Moderate consumption of alcoholic beverages is associated with a reduced risk of coronary heart disease (CHD). Some evidence suggests that red wine is particularly beneficial in this regard and may account in part for the French paradox, although the mechanism of this effect is unknown. We assessed the effects of red wine, ethanol, and quercetin, a major flavonoid constituent of red wine, in coronary resistance vessels (80-150 microm, i.d.) and conductance vessels (300-525 microm, i.d.) of the rabbit. Vessel wall tension was measured in isolated segments maintained in a wire-type myograph (37 degrees C) and preconstricted with 30 mM K+. At an alcohol concentration (14 mM) equivalent to moderate consumption, red wine evoked a small, transient constrictor effect in resistance and conductance vessels (9+/-4%, n = 5; 8+/-1%, n = 7, respectively; p < 0.05). Ethanol alone at this concentration was without effect. Quercetin (5.6, 8, and 30 microM) significantly relaxed resistance (-32+/-4%, n = 10; -47+/-2%, n = 7; -82+/-6%, n = 8, respectively) and conductance (-20+/-3%, n = 8; -32+/-4%, n = 8; -72+/-7%, n = 8, respectively) coronary arteries. Vasorelaxation by quercetin was endothelium-independent and was significantly greater in resistance than in conductance vessels. These data suggest that red wine and ethanol do not evoke relaxation in small coronary arteries at concentrations associated with moderate consumption. Quercetin elicits marked coronary vasorelaxation that is endothelium-independent. However, the concentrations of quercetin necessary to achieve this action are not attained with moderate red wine consumption.

Acute heavy alcohol intake increases silent myocardial ischaemia in patients with stable angina pectoris

OBJECTIVE

To evaluate the effect of acute alcohol ingestion on myocardial ischaemia in patients with coronary heart disease and stable angina.

DESIGN

Randomised crossover study using fruit juice with and without ethanol.

SETTING

Division of cardiology in a university hospital.

PATIENTS

20 patients with stable exertional angina and > or = 50% luminal diameter narrowing of at least one major coronary artery.

INTERVENTIONS

Each patient was studied on two separate days, once after administration of 1.25 g of ethanol per kilogram of body weight diluted to 15% in juice, and once after an equivalent volume of juice; both tests were in the evening and lasted 90 minutes. The patients were scheduled to have 8 periods of walking for 10 min according to a time table. An ambulatory electrocardiogram and the occurrence of anginal attacks were recorded and blood pressure and blood ethanol concentration were measured until the next morning.

RESULTS

The blood ethanol concentration (mean (SD)) rose to 28.8 mmol/l (1.3 (0.4)/1000). Alcohol raised the systolic blood pressure from 132 (16) to 141 (14) mm Hg (P < 0.05 compared with juice). The mean heart rate increased from 57 (7) to 64 (8) beats/min (P < 0.05) for 13 hours after ethanol ingestion compared with juice. The total duration of ischaemia during the ethanol test was 3.5 (median, range 0-80) min, compared with 0 (range 0-67) min for the juice test (P < 0.05). The difference resulted mainly from more silent ischaemia after ethanol ingestion (2.3 (0-80) v 0 (0-67) min; P < 0.05). The ST segment depression time integral increased during the ethanol test (4.4 (0-170) mm x min) relative to that during the juice test (0 (0-103) mm x min; P < 0.01) and especially during the following 13 hours after alcohol (3.5 (0-123) mm x min) compared with juice (0 (0-67) mm x min; P < 0.005). There were no changes in the number, duration, or ST segment depression time integral of the episodes of symptomatic angina, indicating that ethanol augmented the appearance of silent ischaemia.

CONCLUSIONS

Acute heavy ethanol drinking aggravates myocardial ischaemia in patients with stable angina pectoris.

Pressor effect of ethanol in the isolated perfused human placental lobule

Pharmacologically relevant concentrations of ethanol (0.01-0.3 g/%) were perfused via the fetal circulation in isolated human placental lobules. This resulted in a dose-related rise in fetal arterial pressure, which at 0.3 g/% ethanol, was 10.1 +/- 1.1 mmHg above the pre-drug baseline. The pressor responses to ethanol were (i) rapid in onset, reaching a stable plateau within 5-10 min following administration, (ii) readily reversible by perfusion with drug-free media, (iii) non-tachyphylactic and (iv) largely inhibited by the cyclo-oxygenase inhibitor, inhibitor, indomethacin (5 microM). This pressor action of ethanol in the fetal circulation may contribute to the pathogenesis of the fetal alcohol syndrome as well as represent an underlying mechanism of ethanol-induced hypertension.

Effects of acute ingestion of ethanol on hemodynamics and hypoxic pulmonary vasoconstriction in dogs--role of leukotrienes

The effects of acute intragastric administration of ethanol on hemodynamics and hypoxic pulmonary vasoconstriction were studied in spontaneously breathing dogs. The dogs were given 0.5 g/kg of 10% ethanol (v/v) in 5 min. Hemodynamic measurements were obtained before and 30 min after ingestion of ethanol. Mean pulmonary arterial pressure and pulmonary vascular resistance increased markedly after ingestion of ethanol, and hypoxic pulmonary vasoconstriction was augmented significantly by ethanol as well. Diethylcarbamazine citrate (DEC), a lipoxygenase inhibitor, inhibited these effects of ethanol in a dosage of 200 mg/kg. The above findings suggest that ethanol can induce pulmonary vasoconstriction, which may be predominantly mediated by leukotrienes (LTs).

The effect of ethanol on responses of the isolated rabbit ileocolic artery

Antagonist drugs were used to separate the purinergic and adrenergic contributions involved in the sympathetic vasopressor responses produced by electrical field stimulation in the ileocolic artery of the rabbit. Blocking drugs were applied either alone or in various combinations and sequences. The effect of ethanol was studied in conditions of alpha-adrenoceptor blockade, P2x purinoceptor desensitisation, or in the absence of antagonists. From these studies it is concluded that ethanol has a selective potentiating effect on alpha-adrenoceptor-mediated responses.