Emmanouil Karatzis

Effect of coffee on endothelial function in healthy subjects: the role of caffeine

Coffee is one of the most widely used pharmacologically active beverages. The present study was designed to evaluate the acute effect of coffee ingestion on endothelial function in healthy individuals, and the potential role of caffeine. We studied 17 healthy young adults (28.9+/-3.0 years old; nine men), who were regular non-heavy coffee drinkers. The endothelial performance was estimated by endothelium-dependent FMD (flow-mediated dilatation) of the brachial artery before and 30, 60, 90 and 120 min after ingestion of a cup of caffeinated coffee (80 mg of caffeine) or the corresponding decaffeinated beverage (< 2 mg of caffeine) in two separate sessions, following a randomized single-blind cross-over design. There was no difference in baseline FMD values between the two sessions [7.78 compared with 7.07% after caffeinated and decaffeinated coffee respectively; P = NS (not significant)]. Caffeinated coffee led to a decline of FMD (7.78, 2.86, 2.12, 4.44 and 4.57% at baseline, 30, 60, 90 and 120 min respectively; P < 0.001). This adverse effect was focused at 30 (P = 0.004) and 60 min (P < 0.001). No significant effect on FMD was found with the decaffeinated coffee session (7.07, 6.24, 5.21, 7.41 and 5.20%; P = NS). The composite effect of the type of coffee consumed over time on FMD was significantly different (P = 0.021). In conclusion, coffee exerts an acute unfavourable effect on the endothelial function in healthy adults, lasting for at least 1 h after intake. This effect might be attributed to caffeine, given that decaffeinated coffee was not associated with any change in the endothelial performance.

Red wine's antioxidants counteract acute endothelial dysfunction caused by cigarette smoking in healthy nonsmokers

BACKGROUND Long-term smoking is believed to cause endothelial dysfunction via increased oxidative stress, whereas short-term smoking impairs vasodilatation through an as yet undefined mechanism. However, red wine and its constituents have a powerful antioxidant effect both in long-term and acute consumption. The aim of the current study was to investigate whether red wine, with or without alcohol, influences endothelial dysfunction induced by acute cigarette smoking. METHODS Sixteen healthy volunteers (8 males and 8 females) were recruited for a double-blind, crossover study, comprising 3 study days. Each subject smoked 1 cigarette, or smoked and drank 250 mL of red wine, or smoked and drank 250 mL of dealcoholized red wine. Flow-mediated dilatation (FMD) was measured after fasting and 15, 30, 60, and 90 minutes after each trial (smoke or smoke and drink either beverage). RESULTS Acute smoking of 1 cigarette caused a reduction in FMD (P <.001), which was statistically significant 15, 30, and 60 minutes after the inhalation of smoke compared to baseline levels (P <.001, P <.001, P =.043, respectively). However, simultaneous ingestion of either red wine or dealcoholized red wine with smoking did not lead to a change in FMD. CONCLUSIONS Acute smoking caused a significant impairment in endothelial function. Simultaneous consumption of red wine or dealcoholized red wine with smoking decreased smokes harmful effect on endothelium.

Postprandial Improvement of Endothelial Function by Red Wine and Olive Oil Antioxidants: A Synergistic Effect of Components of the Mediterranean Diet

Objective: Consumption of olive oil may cause postprandial impairment of endothelial function, while acute ingestion of red wine seems to improve it. The purpose of the present study was to investigate the combined postprandial effects of two essential components of the Mediterranean diet, red wine and olive oil, on endothelial function. Methods: Fifteen healthy subjects were enrolled in the study, which was comprised of 4 study days. Subjects were asked to consume a standard meal at each study day containing 50gr of olive oil and 250 ml of wine. Two types of wine (red and white; rich and poor in antioxidants respectively) and two types of olive oil (green and refined; rich and poor in antioxidants respectively) were used in a 2*2 design. Endothelium dependent, flow mediated dilatation (FMD) was measured with a B-Mode ultrasound device at fast and 1, 2 and 3 hours postprandially. Results: Combined consumption of red wine and green olive oil (both rich in antioxidants) improved FMD postprandially (p = 0.002, ANOVA for repeated measures), which remained significant 1 hour (p = 0.002) and 2 hours (0.037) following the meal compared to fasting levels. No other combination of wine and olive oil caused any significant alteration on FMD. Conclusion: Acute consumption of both red wine and green olive oil, rich in antioxidants, led to an improvement in the postprandial endothelial function in healthy subjects. These findings provide an additional favorable effect of components of the Mediterranean diet and of their antioxidant substances on endothelial function, at the postprandial state.

Monitoring of arterial stiffness indices by applanation tonometry and pulse wave analysis: reproducibility at low blood pressures.

Objective. Aortic pulse wave analysis (PWA) reveals valuable information related to several hemodynamic characteristics mainly in normotensive and hypertensive patients. The main indices determined by PWA are augmentation index (AI) and reflection time index (RTI), which provide an indirect estimate of arterial stiffness and pulse wave velocity. The objective of the present study was to assess the reproducibility of aortic AI and RTI obtained by an automated and commercially available system (SphygmoCor) applied in patients with low blood pressures where such data are lacking. Methods. The study population consisted of 19 patients with cardiogenic shock due to acute myocardial infarction who underwent mechanical assistance with intraaortic balloon pump. Aortic pressure waveforms were derived from peripheral waveforms—recorded by applanation tonometry of the radial artery—by applying generalized transfer functions. On every occasion, a well-trained operator performed two measurements with 2 min interval. Multiple pairs of measurements were obtained per patient in order to study a wide range of different hemodynamic conditions. Thus, a total of 91 pairs of measurements were performed and analyzed using Bland-Altman plots. Results. AI and RTI ranged within 30–184% and 10–27%, respectively. Within-observer difference was 0.10 ± 5.82% for aortic AI and 0.14 ± 1.2% for RTI. Conclusion. Pulse wave analysis and radial artery tonometry can be used to measure AI and RTI with satisfactory reproducibility even in low blood pressures. Ongoing research is required to establish PWA utility in clinical practice especially at patients with low blood pressures.

Impact of the Metabolic Syndrome on Atrial Size in Patients With New-Onset Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia, and it is strongly related to atrial enlargement. Metabolic syndrome (MetSyn) is associated with increased cardiovascular morbility and mortality. However, the impact of the MetSyn on cardiac arrhythmias is poorly elucidated. The aim of this study was to compare atrial dimensions in patients suffering from nonvalvular paroxysmal AF, with and without MetSyn, trying to identify structural differences that could favor the occurrence of this arrhythmia. The study population consisted of 60 patients who presented with at least 1 episode of paroxysmal AF. From these, 26 patients fulfilled the criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) definition of MetSyn, while the remaining 34 patients did not. Left atrial size was assessed by 2-dimensional echocardiography. Patients with MetSyn had a mean atrial size of 46.2 ∓4.3 mm and those without MetSyn had a mean atrial size of 41.6 ∓1.9 mm, p<0.011. MetSyn may favor the occurrence of paroxysmal AF by increasing atrial size. This concept deserves more research.

Hour-to-hour and week-to-week variability and reproducibility of wave reflection indices derived by aortic pulse wave analysis: implications for studies with repeated measurements.

Background Wave reflections are implicated increasingly in clinical research. Aims The purpose of the present study was to investigate whether wave reflection indices are reproducible when measured repeatedly (more than twice) at longer time intervals, namely hour-to-hour and week-to-week, in healthy subjects; something that has not yet been examined. Methods Bland–Altman plots, the interclass correlation coefficients (ICC) and coefficient of variation were used for this purpose. Two series, with measurements repeated in triplicate, were performed in 22 healthy subjects: the first at intervals of 1 h and the second at 1-week time intervals. Augmentation index (AIx), heart rate-corrected AIx (AI@75) and arrival time of reflected waves at the central aorta (tr) were calculated by aortic pulse wave analysis. Results AIx and AI@75 presented very good to excellent reproducibility (ICC = 0.86) for hour-to-hour repeated measurements, while tr was also highly reproducible (ICC = 0.79). AIx, AI@75 and tr were substantially reproducible when measured repeatedly with 1-week intervals, providing ICCs greater than 0.70. Bland–Altman plots confirmed these results, indicating that more than 90% of AIx, AI@75 and tr measurements fell within two standard deviations of the mean difference. Conclusions Wave reflections are substantially reproducible even when measurements repeated in triplicate are performed at longer time intervals (hours and weeks). A quantifiable amount of variation was reported, which should be taken carefully into consideration in interventional studies with repeated measurements and in observational studies investigating differences or correlations of these indices.

Combined acute effects of red wine consumption and cigarette smoking on haemodynamics of young smokers

Objective Red wine seems to improve haemodynamic variables, while smoking provokes adverse effects. The haemodynamic effects of their combined use is unknown. The purpose of the present study was to examine the acute effects of red wine and its constituents, in combination with the smoking of one cigarette, on haemodynamic parameters, such as blood pressure and wave reflections, in a group of smokers. Methods Twenty smokers (12 males, eight females) participated in a double-blind, crossover study comprised of 3 study days. All subjects either smoked one cigarette, or smoked and drank 250 ml of red wine, or 250 ml of de-alcoholized red wine (containing the same type and similar concentration of antioxidants). Applanation tonometry and generalized transfer functions were used to estimate aortic pressure waveforms at baseline and 30, 60 and 90 min after each trial. The augmentation index (AIx) was used to express wave reflections. Results Smoking increased peripheral systolic blood pressure (P < 0.005) 30 min later, but simultaneous consumption of either type of red wine caused no such effect. Additionally, smoking caused no overall effect on AIx, while smoking and drinking either regular or de-alcoholized red wine reduced AIx (P < 0.001). The reduction of AIx after red wine consumption was significantly greater than the respective reduction after de-alcoholized red wine (P = 0.004). Conclusion Antioxidant substances in red wine counteracted the smoking–induced increase in peripheral systolic blood pressure. Both alcohol and antioxidants in red wine decrease wave reflections in uncomplicated habitual smokers postprandially, indicating an additional favourable effect of red wine.

Acute combined effects of olive oil and wine on pressure wave reflections: another beneficial influence of the Mediterranean diet antioxidants?

Objectives Combined consumption of olive oil and wine is common in the Mediterranean diet, but there are no data concerning their synergistic haemodynamic response. We sought to determine the combined postprandial effects of wine and olive oil on wave reflections and central haemodynamics. Methods Fifteen healthy subjects consumed four standard meals on different days, containing 50 g of olive oil and 250 ml of wine, in a randomized cross-over study design. Two types of wine [red (R) and white (W)] and two types of olive oil [green (G) and refined (O) (rich and poor in antioxidants, respectively)] were used in all possible combinations (RO, RG, WO and WG). Applanation tonometry and aortic pulse wave analysis were performed when fasting and 1, 2 and 3 h postprandially. A second group of 15 healthy individuals matched for age, gender and body mass index served as the control group. Results All meals decreased AIx (RO and RG, P < 0.001; WO, P = 0.007; and WG, P = 0.039). The AIx reduction after RG, RO, WO and WG was significantly different from the respective AIx response of the control group. No difference was observed in the reduction of AIx between sessions, but a significantly earlier peak decrease in AIx, as well as a more prolonged decreasing effect, was observed after RG and RO consumption compared to WO and WG. Central systolic and diastolic pressures were diminished after all four combinations of wine and olive oil (P < 0.05). Conclusions Combined consumption of wine and olive oil provided beneficial postprandial effects on haemodynamics. These findings reveal an additional favourable effect of components of the Mediterranean diet on haemodynamics in the postprandial state.

Acute Smoking Induces Endothelial Dysfunction in Healthy Smokers. Is This Reversible by Red Wine's Antioxidant Constituents?

Objective: Acute smoking causes endothelial dysfunction through impairment of nitric oxide (NO) production, or increased oxidative stress, but the exact mechanism still needs to be elucidated. In healthy non-smokers acute endothelial dysfunction caused by smoking one cigarette was counterbalanced by red wines antioxidants. The aim of the present study is to investigate whether red wines antioxidant substances could counteract the acute endothelial dysfunction induced by acute cigarette smoking in healthy smokers as well. Methods: Twenty healthy volunteers (12 males) participated in a double-blind, cross-over study, comprised of three study days. All subjects either smoked one cigarette, or smoked and drank 250 ml of red wine, or smoked and drank 250 ml of dealcoholized red wine in each one of the study days. Flow mediated dilatation (FMD) was measured at fast and 30, 60 and 90 minutes after each trial. Results: Smoking one cigarette induced a significant decrease in FMD (p < 0.001), which remained significant 30 (p < 0.001), and 60 (p = 0.003) minutes after the end of smoking. FMD remained statistically unchanged after consumption of either regular red wine, or dealcoholized red wine together with smoking. Conclusions: The observed endothelial dysfunction following smoking of one cigarette was counterbalanced by consumption of either red wine or dealcoholized red wine in healthy smokers. It is possible that acute endothelial dysfunction caused by smoking could be attributed to increased oxidative stress and red wines antioxidants counteract these acute effects of smoke on endothelium.

Endothelial dysfunction and type of cigarette smoked: the impact of 'light' versus regular cigarette smoking

Acute cigarette smoking leads to temporary endothelial dysfunction, which is an early event in atherogenesis. Sufficient data concerning the effect of cigarettes with low tar and nicotine yield are lacking. Seventeen healthy individuals (nine women, eight men, aged 27.8 3.6 years) were subjected to evaluation of endothelial function by means of endothelium-dependent, flow-mediated dilatation (FMD) of the brachial artery, before, immediately after and 30, 60 and 90 min after smoking a regular cigarette (nicotine 0.9 mg, tar 12 mg) or the corresponding ‘light’ cigarette (nicotine 0.6 mg, tar 8 mg). The following day, measurements were repeated after smoking the opposite kind of cigarette. Baseline FMD was 6.1 1.6% and 7.2 2.0% in the light and regular cigarette groups, respectively (p 1/4 NS). The overall effect of the regular cigarette over time on FMD compared with the light cigarette was significantly different (F 1/4 3.039, p 1/4 0.023). FMD was significantly depressed after smoking both types (light: F 1/4 8.192, p < 0.001; regular: F 1/4 16.698, p < 0.001). Immediately after smoking, FMD declined in both groups (light: 3.0 2.4% and regular: 1.6 3.2%, p < 0.001 and p < 0.001, respectively), and it remained significantly depressed in the regular cigarette group at 30 min (0.75 1.5%, p < 0.001) and 60 min (3.5 3.1%, p 1/4 0.024), while in the light cigarette group FMD differences were abolished at 30, 60 and 90 min after smoking. In conclusion, acute smoking of both regular and light cigarettes leads to temporary vasomotor dysfunction; its duration is shorter after smoking a ‘light’ cigarette.