Grgo Gunjaca

Antioxidant and vasodilatory effects of blackberry and grape wines.

In contrast to the well-described various biological effects of grape wines, the potential effects of commonly consumed blackberry wine have not been studied. We examined in vitro antioxidant and vasodilatory effects of four blackberry wines and compared them with the effects of two red and two white grape wines. Although some blackberry wines had lower total phenolic content relative to the red grape wines, their antioxidant capacity was stronger, which may be related to a higher content of non-flavonoid compounds (most notably gallic acid) in blackberry wines. Although maximal vasodilation induced by blackberry wines was generally similar to that of red wines, blackberry wines were less potent vasodilators. Vasodilatory activity of all wines, in addition to their flavonoid and total phenolic content, was most significantly associated with their content of anthocyanins. No association of vasodilation with any individual polyphenolic compound was found. Our results indicate the biological potential of blackberry wines, which deserves deeper scientific attention.

Comparison of acute effects of red wine, beer and vodka against hyperoxia-induced oxidative stress and increase in arterial stiffness in healthy humans

OBJECTIVE We determined and compared acute effects of different alcoholic beverages on oxygen-induced increase in oxidative stress plasma marker and arterial stiffness in healthy humans. METHODS Ten males randomly consumed one of four tested beverages: red wine (RW), vodka, beer (0.32 g ethanol/kg body wt) and water as control. Every beverage was consumed once, a week apart, in a cross-over design. The volunteers breathed 100% normobaric O(2) between 60th and 90th min of 3h study protocol. Plasma lipid peroxides (LOOH) and uric acid (UA) concentration, blood alcohol concentration (BAC) and arterial stiffness (indicated by augmentation index, AIx) were measured before and 30, 60, 90, 120 and 180 min after beverage consumption. RESULTS Intake of all alcoholic beverages caused a similar increase of BAC. The oxygen-induced elevation in AIx was similarly reduced in all three groups relative to the control (3.4 ± 1.3%, 5.4 ± 2.2% and 0.2 ± 1.6% vs. 13.7 ± 2.6% for red wine, vodka, beer and control, respectively, 60 min after intake). Exposure to oxygen resulted in increased plasma LOOH in all groups. However, in RW group this increase was lowest (1.1 ± 0.5) in comparison to the vodka (2.1 ± 0.5), beer (1.6±0.3) and control (2.5 ± 0.4μM/L H(2)O(2)). 60 min after intake of RW and beer plasma UA significantly increased (34 ± 4 and 15 ± 3) in contrast to vodka and control (-6 ± 2 and -8 ± 2μmol/L). CONCLUSION All three alcoholic beverages provided similar protection against oxygen-induced increase in arterial stiffness, probably due to central vasodilatatory effect of alcohol itself, but only RW provided protection against oxygen-induced oxidative stress.

Sex-specific association of anthropometric measures of body composition with arterial stiffness in a healthy population

Summary Background Anthropometric measures of body composition and arterial stiffness are commonly used as indicators of cardiovascular risk. Little is known, however, about the association of the anthropometric measures with arterial stiffness, especially in a healthy, generally non-obese population. Material/Methods In a sample of 352 healthy subjects (200 premenopausal women), 3 arterial stiffness indices were analyzed (pulse wave velocity, augmentation index and central systolic blood pressure) in relation to 5 anthropometric measures of body composition (body mass index – BMI, body fat percentage by skinfold measurements –%BF, waist circumference – WC, waist-hip ratio – WHpR, and waist-height ratio – WHtR). Data were analyzed using correlation and regression analyses, with adjustment for the following confounders: age, blood pressures, height, heart rate, blood lipids and smoking. Results Most correlations between anthropometric measures and arterial stiffness indices were significant and positive in both sex groups (r=0.14–0.40, P<0.05). After adjustment for confounding effects, BMI, WC and WHtR remained significant (but inverse) predictors of arterial stiffness (β from −0.06 to −0.16; P<0.05) in the females, while in the males BMI was the only measure inversely predicting arterial stiffness (β from −0.09 to −0.13; P<0.05). Conclusions Measures of body composition are weak and inverse predictors of arterial stiffness and their influence is sex-dependent. BMI, WC and WHtR were key predictors of arterial stiffness in the females, while BMI was the principal predictor in the males. The associations of anthropometric measures with arterial stiffness are strongly and differently confounded by various factors that have to be taken into account when explaining results of similar studies.

A complex pattern of agreement between oscillometric and tonometric measurement of arterial stiffness in a population-based sample

Objective: Arterial stiffness can be estimated by several noninvasive methods. In a large population-based sample we performed an agreement analysis of the set of arterial stiffness indices (ASIs) measured by tonometric (SphygmoCor) and oscillometric (Arteriograph) techniques. Methods: Central augmentation index (cAIx) and peripheral augmentation index (pAIx), as well as central SBP (cSBP) were measured in 1012 participants from a population-based study. Data were analyzed using Bland–Altman agreement analysis, multivariate adaptive regression splines and Fishers linear discriminant analysis. Results: In contrast to high initial correlation between two devices (r = 0.87 for pAIx, 0.88 for cAIx and 0.95 for cSBP), plotting against each other the values of measured ASIs revealed their uneven distribution and grouping into three distinctive clusters of participants. The strongest cluster discriminators were age and DBP (cluster 1: age <40, DBP 70.42 ± 7.41; cluster 2: age >40, DBP 77.36 ± 10.16; cluster 3: age >60, DBP 82.56 ± 9.48). Bland–Altman analysis of clusters showed complex differences in agreement pattern for cAIx and pAIx. For cAIx SphygmoCor gives lower readings, especially in cluster 1, whereas for pAIx Arteriograph gives lower readings in cluster 1 and higher readings in clusters 2 and 3. The agreement for pAIx was better in younger participants and the same for cAIx in older participants. Conclusion: ASIs obtained by SphygmoCor and Arteriograph cannot be interchangeably used as they seem to be differently influenced by predictors of arterial stiffness, predominantly by age. Different pattern of pAIx and cAIx agreement across clusters demonstrates importance of distinguishing cAIx and pAIx. Homogeneity of the study population for age should be considered when interpreting results of the studies investigating ASI.

Acute application of antioxidants protects against hyperoxia-induced reduction of plasma nitrite concentration.

We investigated the effects of acute intake of antioxidants on hyperoxia‐induced oxidative stress, reduction of plasma nitrite and change in arterial stiffness. Twelve healthy males randomly consumed either placebo or an oral antioxidant cocktail (vitamin C, 1000 mg; vitamin E, 600 IU; alpha‐lipoic acid, 600 mg). Every therapy was consumed once, a week apart, in a cross‐over design, 30 min before the experiment. The volunteers breathed 100% normobaric oxygen between 30th and 60th min of 1‐h study protocol. Plasma levels of nitrite, lipid peroxides (LOOH) and vitamin C, arterial stiffness (indicated by augmentation index, AIx) and arterial oxygen (PtcO2) pressure were measured before and after hyperoxia. Exposure to oxygen caused a similar increase of PtcO2 in both placebo and antioxidants groups, confirming comparable exposure to hyperoxia (438 ± 100 versus 455 ± 83 mm Hg). Vitamin C was increased in the antioxidants group confirming successful application of antioxidants (69 ± 14 versus 57 ± 15 μm). Hyperoxia resulted in increased AIx and LOOH and decreased nitrite in placebo (−32 ± 11 versus −47 ± 13%, 72 ± 7 versus 62 ± 6 μm H2O2 and 758 ± 184 versus 920 ± 191 nm, respectively), but not in the antioxidants group (−42 ± 13 versus −50 ± 13%, 64 ± 9 versus 61 ± 8 μm H2O2 and 847 ± 156 versus 936 ± 201 nm, respectively). The acute intake of selected antioxidants was effective in preserving bioavailabity of ˙NO and vascular function, against hyperoxia‐induced oxidative stress.

Normative equations for central augmentation index: assessment of inter-population applicability and how it could be improved

Common reference values of arterial stiffness indices could be effective screening tool in detecting vascular phenotypes at risk. However, populations of the same ethnicity may differ in vascular phenotype due to different environmental pressure. We examined applicability of normative equations for central augmentation index (cAIx) derived from Danish population with low cardiovascular risk on the corresponding Croatian population from the Mediterranean area. Disagreement between measured and predicted cAIx was assessed by Bland-Altman analysis. Both, cAIx-age distribution and normative equation fitted on Croatian data were highly comparable to Danish low-risk sample. Contrarily, Bland-Altman analysis of cAIx disagreement revealed a curvilinear deviation from the line of full agreement indicating that the equations were not equally applicable across age ranges. Stratification of individual data into age decades eliminated curvilinearity in all but the 30–39 (men) and 40–49 (women) decades. In other decades, linear disagreement independent of age persisted indicating that cAIx determinants other than age were not envisaged/compensated for by proposed equations. Therefore, established normative equations are equally applicable to both Nordic and Mediterranean populations but are of limited use. If designed for narrower age ranges, the equations’ sensitivity in detecting vascular phenotypes at risk and applicability to different populations could be improved.

The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function

Self‐contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer‐lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive.