Lidija Rašić

Adrenergic System Activation Mediates Changes in Cardiovascular and Psychomotoric Reactions in Young Individuals after Red Bull© Energy Drink Consumption

Objectives. To assess the effect of Red Bull© on (1) blood glucose and catecholamine levels, (2) cardiovascular and respiratory function changes before, during, and after exercise, (3) reaction time, (4) cognitive functions, and (5) response to mental stress test and emotions in young healthy individuals (N=38). Methods. Heart rate (HR) and arterial blood pressure (ABP), blood glucose, adrenaline, and noradrenalin plasma levels were measured before and after Red Bull© intake. Participants were subjected to 4 different study protocols by randomized order, before and 30 minutes after consumption of 500 mL of Red Bull©. Results. Mean ABP and HR were significantly increased at rest after Red Bull© intake. Blood glucose level and plasma catecholamine levels significantly increased after Red Bull© consumption. Heart rate, respiration rate, and respiratory flow rate were significantly increased during exercise after Red Bull© consumption compared to control condition. Intake of Red Bull© significantly improved reaction time, performance in immediate memory test, verbal fluency, and subjects attention as well as performance in mental stress test. Conclusion. This study demonstrated that Red Bull© has beneficial effect on some cognitive functions and effect on cardiovascular and respiratory system at rest and during exercise by increasing activity of the sympathetic nervous system.

Acute Hyperbaric Oxygenation, Contrary to Intermittent Hyperbaric Oxygenation, Adversely Affects Vasorelaxation in Healthy Sprague-Dawley Rats due to Increased Oxidative Stress

The present study was aimed at assessing endothelium-dependent vasorelaxation, at measuring superoxide production in the aorta and femoral artery, and at determining antioxidative enzyme expression and activity in aortas of male Sprague-Dawley rats (N = 135), randomized to an A-HBO2 group exposed to a single hyperbaric oxygenation session (120′ of 100% O2 at 2.0 bars), a 24H-HBO2 group (single session, examined 24 h after exposure), a 4D-HBO2 group (4 consecutive days of single sessions), and a CTRL group (untreated group). Vasorelaxation of aortic rings in response to acetylcholine (AChIR) and to reduced pO2 (HIR) was tested in vitro in the absence/presence of NOS inhibitor L-NAME and superoxide scavenger TEMPOL. eNOS, iNOS, antioxidative enzyme, and NADPH oxidase mRNA expression was assessed by qPCR. Serum oxidative stress markers and enzyme activity were assessed by spectrometry, and superoxide production was determined by DHE fluorescence. Impaired AChIR and HIR in the A-HBO2 group were restored by TEMPOL. L-NAME inhibited AChIR in all groups. Serum oxidative stress and superoxide production were increased in the A-HBO2 group compared to all other groups. The mRNA expression of iNOS was decreased in the A-HBO2 and 24H-HBO2 groups while SOD1 and 3 and NADPH oxidase were increased in the 4D-HBO2 group. The expression and activity of catalase and glutathione peroxidase were increased in the 4D-HBO2 group as well. AChIR was NO dependent. Acute HBO2 transiently impaired vasorelaxation due to increased oxidative stress. Vasorelaxation was restored and oxidative stress was normalized 24 h after the treatment.

7D.04: ACUTE SALT LOADING AFFECTS VASCULAR FUNCTION WITHOUT SIGNIFICANT CHANGE IN BODY FLUID STATUS AND BODY COMPOSITION IN YOUNG HEALTHY WOMEN.

Objective: Our previous study demonstrated that one week of salt loading significantly impaired skin microvascular reactivity without changes in blood pressure (BP) levels. The aim of this study was to evaluate whether one week of high-salt (HS) diet changes body fluid status and body composition subsequently affecting vascular reactivity. Design and method: 10 healthy women (age range 20–23) took a 7-days low-salt (LS) diet (<40mmol Na/day) and 7-days HS diet (∼240mmol of Na/day). Salt resistance, defined as a <5 mmHg change in BP determined while on the LS and HS diets was confirmed in all subjects. Skin microvascular post occlusive reactive hyperemic (PORH) blood flow (indicator of endothelial function) was assessed by laser Doppler flowmetry (LDF) before and after each diet protocol. Plasma Renin Activity (PRA), plasma aldosterone, plasma and 24h-urine sodium, potassium, urea and creatinine levels were measured before and after diets. Body composition was assessed with a four-terminal portable impedance analyzer (Maltron Bioscan 920-II). Body Mass Index (BMI), Fat Free Mass% (FFM%), Fat Mass% (FM%), Total Body Water% (TBW%), Extracellular Water% (ECW%), Intracellular Water (ICW%), ECW/ICW, Plasma Fluid (PF), Interstitial Fluid (IF) and Body Density Mass (BDM) were calculated. Results: Changes in 24 h urinary sodium, PRA and plasma aldosterone levels confirmed subjects conformed to the diet. There was no change in BP and HR before and after both diet protocols. HS diet caused significant impairment in microvascular reactivity (PORH) (R-O LS diet 156 ± 23% vs. HS diet 100 ± 12%, P = 0.040). One week HS diet did not induce any significant change in body composition parameters BMI, FFM%, FM% and BDM, compared to LS diet. Body fluid components (TBW%, ECW%, ICW%, ECW/ICW, PF and IF) were not different in LS compared to HS group. Conclusions: This study confirmed that even one week of HS diet significantly altered microvascular reactivity in young healthy normotensive and salt-resistant women, without changes in BP. Furthermore, our results indicate that vascular changes after HS diet are independent of body composition and body fluid status just as they are pressure independent, but are consequence of unique effect of HS on endothelial function.

IS THERE A SEX-RELATED DIFFERENCE IN ENDOTHELIUM-DEPENDENT MICROVASCULAR RESPONSE TO ACUTE SALT LOADING IN YOUNG HEALTHY INDIVIDUALS?

Objective: We have earlier reported that acute salt loading affects acetylcholine (ACh) induced vasodilation (endothelium-dependent) in forearm skin microcirculation in young healthy women independently of blood pressure (BP) changes. The aim of the present study was to test is there a sex-related difference in endothelium-dependent forearm skin microvascular response to acute salt loading in young healthy individuals. Design and method: 16 young healthy men participated in this study (age range 19–24). All subjects took 7-days low-salt (LS) diet – washout period (<3.2 g salt/day) followed by 7-days HS diet (∼14 g salt/day). Skin microvascular blood flow measurement was done using Laser Doppler Flowmetry in response to iontophoresis of acetylcholine (ACh) before and after diet protocols. BP and heart rate (HR) were measured at the beginning of each visit (mean of three repeated measurements). 24h-urine sodium, potassium, urea and creatinine levels were measured before and after diet protocols. Salt intake was estimated based on calculation of 24-hour urinary sodium excretion. Results: Changes in 24 h urinary sodium excretion and calculated salt intake confirmed that subjects conformed to the diet protocols. There was no significant difference in BMI and WHR before and after HS diet. There was no change in BP and HR before and after HS diet. In accordance with our earlier results obtained in young healthy women (flow change compared to basic flow: before HS diet 1797 ± 523 vs. after HS diet 1309 ± 751, P = 0.024; Physiology 2016), ACh induced dilation was significantly impaired after HS diet protocol in young healthy men as well (flow change compared to basic flow: before HS diet 2157 ± 1048 vs. after HS diet 1592 ± 586, P = 0.014). Conclusions: The results of the present study demonstrated that 7-days HS diet impairs forearm skin microvascular ACh-induced dilation independently of BP changes in young healthy men, just as we earlier reported in women. Eventhough there are many known sex-related differences in various cardiovascular responses even in healthy individuals, the results of this study suggesst that one week HS loading affects endothelium-dependent vasodilation in peripheral microcirculation correspondingly in young healthy men and women.

ACUTE DIETARY SALT MODULATION INDUCES CHANGES IN DYNAMICS OF MONOCYTES SUBSETS IN YOUNG HEALTHY WOMEN

Objective: Our earlier studies have demonstrated that 7-days high-salt (HS) intake alters micro- and macrovascular response, and increases oxidative stress level in young healthy women independently of blood pressure (BP) changes. Still, it is not clarified whether such HS-induced endothelial dysfunction also involves changes in the immune system response which finally leads to vascular inflammation. Thus, the aim of this study was to assess the effect of 7-days salt intake modulation on monocyte subpopulations distribution and its activation in peripheral blood of young healthy women. Design and method: 15 young healthy women who all took 7-days low-salt (LS) diet (<3.2 g salt/day) followed by 7-days HS diet (∼14 g salt/day) participated in this study. Blood pressure (BP) was measured, and 24 h urine samples were analyzed for sodium, potassium, urea and creatinine levels before and after diet protocols. Flow cytometry analysis of circulating monocyte subpopulations distribution was assessed by determination of ‘classical’, ‘non-classical’ and ‘inflammatory’ monocytes based on CD14 and CD16 molecule expression in peripheral blood of young healthy women. Also, monocytes activation was assessed by measurement of lymphocyte function-associated antigen 1 (LFA-1, Cd 11a) expression which is known as ligand for endothelial cell adhesion molecules (ICAM-1). Results: Changes in 24 h urinary sodium confirmed subjects conformed to the diet protocol. There was no change in BP after HS diet. CD14+CD16++ gated (non-classical) monocytes from peripheral blood significantly decreased after HS diet compared to the LS diet. Distribution of CD14++CD16+ (intermediate) and CD14++CD16- (classical) gated monocytes from peripheral blood did not change after HS diet compared to the LS diet. CD11a expression on all three gated monocyte subpopulations was significantly decreased after HS diet compared to LS diet measurement. Conclusions: The results of the present study demonstrated that 7-days HS loading decreased CD14+CD16++ monocytes subpopulation (non-classical monocytes) which usually acts as endothelium housekeepers, and also decreased total monocytes (all three subpopulations) expressing high level of CD11a in young healthy women, probably due to activated monocytes adhesion and migration through endothelium layer to the place of endothelial injury.

VASCULAR NO AND SUPROXIDE PRODUCTION IS INFLUENCED BY HIGH DIETARY SALT INTAKE IN TFF3−/− MICE

Objective: Arachidonic acid metabolism and products are shown to affect vascular reactivity mechanism. TFF3−/− mice have protective phenotype of favorable ratio of &ohgr;6/&ohgr;-3 fatty acids and modified metabolism of arachidonic acid. However, the role of TFF3 peptide in hypertension and vascular function is still underinvestigated. The aim of this study was to asses the effect of high salt diet on flow-induced endothelial NO and superoxide production in carotid arteries of wild type mice of mixed background C57Bl6/Sv/129 (WT) and TFF3−/− knock out mice with the same background. Design and method: Eleven weeks old male TFF3−/− or WT mice were divided in 2 groups (N = 4 per group): low salt (LS) and high salt (HS; 4% NaCl for 7 days). Following dietary protocol, mice were anaesthetized with ketamine (75 mg/kg) and midazolam (2.5 mg/kg). Carotid arteries were isolated and cannulated on pressure myograph with or without flow (at delta 80 mmHg), in the absence/presence of the NOS inhibitor L-NAME. NO production was determined by DAF-2DA to DAF-2T conversion fluorescence assay. To assess the production of superoxide radicals, the carotid arteries were loaded with dihydroethidine (DHE, 20 &mgr;M). All experimental procedures conformed to the European Guidelines for the Care and Use of Laboratory Animals (directive 86/609) and were approved by institutional Ethical Committee. p < 0.05 was significant. Results: Basal NO production in no-flow condition was similar among groups. L-NAME blocked the production of NO in all groups. Flow-induced NO production was decreased in HS-WT group compared to no-flow conditions in HS-WT group, and compared to LS-WT group and LS-TFF3−/− group (p < 0.05). There were no changes in endothelial NO production in TFF3−/− mice. Superoxide production was increased in LS-TFF3−/− no-flow group compared to LS-WT in no-flow condition Flow-induced superoxide production was increased in both HS-WT and HS-TFF3−/− groups compared to corresponding LS groups. Conclusions: HS intake decreases flow-induced vascular NO production in WT mice probably due to increased oxidative stress. However, HS intake does not affect NO production in TFF3−/− mice eventhough superoxide levels are increased in basal levels and in flow conditions, suggesting protective role of this phenotype on NO bioavailability.

Acute exhaustive rowing exercise reduces skin microvascular dilator function in young adult rowing athletes

PurposeThe effect of acute exhaustive exercise session on skin microvascular reactivity was assessed in professional rowers and sedentary subjects. A potential involvement of altered hemodynamic parameters and/or oxidative stress level in the regulation of skin microvascular blood flow by acute exercise were determined.MethodsAnthropometric, biochemical, and hemodynamic parameters were measured in 18 young healthy sedentary men and 20 professional rowers who underwent a single acute exercise session. Post-occlusive reactive hyperemia (PORH), endothelium-dependent acetylcholine (ACh), and endothelium-independent sodium nitroprusside (SNP) microvascular responses were assessed by laser Doppler flowmetry in skin microcirculation before and after acute exercise. Serum lipid peroxidation products and plasma antioxidant capacity were measured using spectrophotometry.ResultsAt baseline, rowers had significantly lower diastolic blood pressure (DBP) and heart rate (HR), and higher stroke volume (SV), PORH, and endothelium-dependent vasodilation than sedentary. Acute exercise caused a significant increase in systolic blood pressure, DBP, HR, and SV and a decrease in total peripheral resistance in both groups. Acute exercise induced a significant impairment in PORH and ACh-induced response in rowers, but not in sedentary, whereas the SNP-induced vasodilation was not affected by acute exercise in any group. Antioxidant capacity significantly increased only in sedentary after acute exercise.ConclusionSingle acute exercise session impaired microvascular reactivity and endothelial function in rowers but not in sedentary, possibly due to (1) more rowing grades and higher exercise intensity achieved by rowers; (2) a higher increase in arterial pressure in rowers than in sedentary men; and (3) a lower antioxidant capacity in rowers.

Omega-3 Polyunsaturated Fatty Acids Enriched Hen Eggs Consumption Enhances Microvascular Reactivity in Young Healthy Individuals

The beneficial effect of omega-3 polyunsaturated fatty acids (PUFA) supplementation on the cardiovascular (CV) system is well supported in CV patients; however, the effect of the consumption of omega-3 PUFA-enriched functional food in healthy individuals is still not fully elucidated. This study aimed to determine the effect of the consumption of omega-3 PUFA-enriched hen eggs on the microvascular reactivity (primary outcome), blood pressure (BP), and serum lipid profile in young healthy individuals. The control group (N = 16) ate 3 ordinary hen eggs (277 mg of omega-3 PUFAs/day), and the OMEGA-3 group (N = 20) ate 3 omega-3 PUFA-enriched eggs containing 259 mg of omega-3 PUFAs/egg daily (α-linolenic acid (ALA), 167 mg/egg; eicosapentaenoic acid (EPA), 7 mg/egg; docosahexaenoic acid (DHA), 84 mg/egg) for 3 weeks (777 mg of omega-3 PUFA/day). Postocclusive reactive hyperemia (PORH) in skin microcirculation assessed by laser Doppler flowmetry, serum lipid profile, fasting blood glucose, high-sensitivity C-reactive protein (hsCRP), and arterial BP were measured in all subjects before and after the protocol. PORH was significantly enhanced, and triglycerides, hsCRP, and BP were significantly decreased in the OMEGA-3 group compared with baseline measurements, whereas there was no significant difference in the control group after the protocol when compared with baseline. To the best of our knowledge, this is the first study to demonstrate that consumption of a mixture of omega-3 PUFA (ALA + EPA + DHA), provided via enriched hen eggs, elicits changes in the microvascular reactivity, BP, and triglyceride level in healthy subjects that are associated with CV benefits, thus suggesting that daily consumption of omega-3 PUFA-enriched eggs in healthy individuals may potentially contribute to CV risk factor attenuation and disease prevention.

Sex-related Differences in Correlation of Overweight/Obesity Markers to Blood Pressure in Prepubertal Children in Osijek-Baranja County - a Cross-sectional Study

Background: The aim was to assess prevalence of overweight/obesity and evaluate their relations to blood pressure and blood glucose concentrations in prepubertal school children. Design and method: Third grade elementary school children were included (total 111-53 girls, 58 boys; 9±1 years). Height, weight, body mass index (BMI), waist circumference (WC), upper arm and thigh skin fold (ASF, TSF) and systolic (SBP) and diastolic blood pressure (DBP) and fasting blood glucose concentrations (fBGC) were measured. Results: 13.51% subjects were overweight (BMI>85th percentile; 3 girls and 12 boys) and 15.32% subjects were obese (BMI>95th percentile;7 girls and 10 boys). Boys had significantly higher SBP than girls. Overweight/obese boys had significantly thicker ASF and TSF, higher SB, higher DBP (and higher fBGC compared to normal-weight boys; 5 boys and 4 girls were hypertensive (SBP>95th percentile). In boys, there were significant positive correlations of BMI and WC with SBP, DBP, ASF and TSF. Overweight/ obese girls had significantly thicker ASF and TSF and greater WC compared to normal-weight girls. SBP, DBP or fBGC were not significantly different between OW/OB and normal-weight girls. In girls, BMI and WC significantly positively correlated with ASF and TSF, but no correlations to BP were observed. WC positively correlated to fBGC in both, boys and girls. Conclusions: Significant association of OW/OB to arterial BP levels in prepubertal boys and a lack of associations among OW/OB markers and arterial BP levels in girls suggest that OW/OB might not be as important risk factors in development of hypertension in adulthood in females as in males.

[OP.5A.06] HIGH SALT DIET-INDUCED MICROVASCULAR DYSFUNCTION IS ASSOCIATED WITH REDUCED ANTIOXIDANT CAPACITY IN YOUNG HEALTHY WOMEN

Objective: Our previous study demonstrated that one week of high salt (HS) loading significantly impaired skin microvascular reactivity without changes in blood pressure (BP) levels. The aim of this study was to evaluate if this HS diet-induced microvascular dysfunction is associated with changes in antioxidant capacity in young healthy women. Design and method: Young healthy women (N = 33) were assigned to take HS diet (about 14 g of NaCl/day) for 7 days. BP and heart rate (HR) were measured before and after diet protocol. Post-occlusive reactive hyperemia (PORH) in the skin microcirculation was assessed by laser Doppler flowmetry (LDF). Plasma and 24 h-urine sodium were measured before and after diet protocol. Compliance to the prescribed diet was assessed by calculating salt intake from 24 h-urinary sodium excretion. As an idicator of antioxidant capacity, the ferric reducing ability of plasma - the FRAP assay with Trolox used as standard (mM Trolox) (spectrophotometric method) was detected before and after diet protocol. Results: There was no change in BP and HR before and after diet protocol. Changes in 24 h urinary sodium and calculated salt intake (salt intake/g before HSD 6.4 ± 2.6 vs. post HS diet 11.8 ± 5.9, P < 0.001) confirmed subjects conformed to the diet. HS diet caused significant impairment in PORH (R-O before HS diet 136 ± 49% vs. post HS diet 110 ± 29%, P = 0.017). One week of HS diet significantly reduced FRAP (antioxitant capacity) (FRAP mM/L before HS diet 0.68 ± 0.29 vs. after HS diet 0.61 ± 0.27, P = 0.019). We found positive correlation between R-O value (measure of PORH) and FRAP (antioxidant capacity) (r = 0.454, P < 0.001), while there was negative correlation between salt intake and FRAP (r = -0.262, P = 0,031) just as between salt intake and R-O (r = -0.324, P = 0.007). Conclusions: This study confirmed our previous results that one week HS diet significantly altered microvascular reactivity in young healthy normotensive women, without changes in BP. Furthermore, our results have shown that HS diet significantly reduced antioxidant capacity which can be associated with microvascular dysfunction, since there is positive correlation between microvascular reactivity and FRAP assay in young healthy women.