Sanja Novak

Hyperbaric oxygenation modulates vascular reactivity to angiotensin-(1-7) in diabetic rats: potential role of epoxyeicosatrienoic acids.

Previously, a facilitating effect of hyperbaric oxygenation (HBO2) on aortic ring responses to angiotensin-(1-7) in healthy rats was reported, with epoxyeicosatrienoic acids (EETs) possibly playing an important role. The aim of this study was to assess whether HBO2 exerts similar effects in diabetic rats and to further explore the role of specific cytochrome P450 (CYP) enzymes in changes induced by HBO2. Aortic relaxation to angiotensin-(1-7) was significantly higher in HBO2 diabetic rats compared to control diabetic rats, while HBO2 had no effect on angiotensin II contraction. N-methylsulphonyl-6-(2-propargyloxyphenyl/hexanamide inhibited the facilitation of angiotensin-(1-7) responses in HBO2 rats, suggesting an important role of EETs in this modulation. mRNA expression of CYP2J3 and protein expression of CYP2C11 were significantly upregulated in HBO2 diabetic rats, whereas CYP4A1, CYP4A2 and CYP4A3 mRNA and CYP2J3 protein expression was similar between groups. Mean arterial pressure, ferric reducing ability of plasma and Thiobarbituric Acid Reactive Substances levels and serum angiotensin-(1-7) concentrations were not significantly changed.

Attenuated flow-induced dilatation of middle cerebral arteries is related to increased vascular oxidative stress in rats on a short-term high salt diet.

Recent studies have shown that high salt (HS) intake leads to endothelial dysfunction and impaired vascular reactivity in different vascular beds in both animal and human models, due to increased oxidative stress. The objective of this study was to assess vascular response to flow‐induced dilatation (FID) and to elucidate the role of vascular oxidative stress/antioxidative capacity in middle cerebral arteries (MCAs) of HS‐fed rats in vitro. The novelty of this study is in demonstrating impaired flow‐induced dilatation of MCAs and down‐regulation of vascular antioxidant genes with HS intake, leading to increased levels of oxidative stress in blood vessels and peripheral lymph organs, which together contribute to impaired FID. In addition, results show increased oxidative stress in leukocytes of peripheral lymph organs, suggesting the occurrence of inflammatory processes due to HS intake. Recirculation of leukocytes might additionally increase vascular oxidative stress in vivo.

Reduced Dietary Selenium Impairs Vascular Function by Increasing Oxidative Stress in Sprague-Dawley Rat Aortas

This study aimed to determine whether low dietary Se content affects the function and mechanisms mediating the vascular relaxation of rat aortas, and to test the role of oxidative stress in observed differences. Male Sprague Dawley (SD) rats were maintained for 10 weeks on low Se (low-Se group; N = 20) or normal Se content (norm-Se group; N = 20) rat chow. Dose responses to acetylcholine (ACh; 10−9–10−5M) and the response to reduced pO2 were tested in noradrenaline-precontracted aortic rings in the absence/presence of the nitric oxide synthase (NOS) inhibitor nitro-l-arginine methyl ester (l-NAME), the cyclooxygenase 1 and 2 (COX-1, 2) inhibitor Indomethacin, and the antioxidative agent Tempol in tissue bath. mRNA expression of glutathione peroxidase 1 (GPx1), catalase (CAT), and Cu/Zn superoxide dismutase (SOD) was measured in rat aortas. Oxidative stress (Thiobarbituric Acid Reactive Substances; TBARS), antioxidative plasma capacity (ferric reducing ability of plasma assay; FRAP), and protein levels of GPx1 were measured in plasma and serum samples, respectively. Reduced ACh-induced relaxation (AChIR) (dominantly mediated by NO) in the low-Se group compared to the norm-Se group was restored by Tempol administration. Hypoxia-induced relaxation (HIR) (dominantly mediated by COX-1, 2), TBARS, and FRAP as well as GPx1 serum concentrations were similar between the groups. mRNA GPx1 expression in rat aortas was significantly decreased in the low-Se compared to the norm-Se group. These data suggest that low dietary Se content increases the local oxidative stress level, which subsequently affects the NO-mediated vascular response.

Hyperbaric oxygenation and 20- hydroxyeicosatetreanoic acid inhibition reduce stroke volume in female diabetic Sprague–Dawley rats

What is the central question of this study? Is there a beneficial effect and what are the mechanisms of acute and multiple hyperbaric oxygenation (HBO2) exposures on the outcome of cerebral tissue injury induced by a transient middle cerebral artery occlusion model in diabetic female rats? Are 20‐hydroxyeicosatetreanoic acid and epoxyeicosatrienoic acids involved? What is the main finding and its importance? Equal reduction of cortical and total infarct size in rats treated with HBO2 and HET0016 (20‐hydroxyeicosatetreanoic acid production inhibitor) and significant mRNA upregulation of epoxyeicosatrienoic acid‐producing enzymes (Cyp2J3 and Cyp2C11) in treated groups suggest that HBO2 and HET0016 are highly effective stroke treatments and that cytochrome P450 metabolites are involved in this therapeutic effect.

Anti-Inflammatory Effects of Hyperbaric Oxygenation during DSS-Induced Colitis in BALB/c Mice Include Changes in Gene Expression of HIF-1α, Proinflammatory Cytokines, and Antioxidative Enzymes

Reactive oxygen species (ROS) and nitrogen species have an indispensable role in regulating cell signalling pathways, including transcriptional control via hypoxia inducible factor-1α (HIF-1α). Hyperbaric oxygenation treatment (HBO2) increases tissue oxygen content and leads to enhanced ROS production. In the present study DSS-induced colitis has been employed in BALB/c mice as an experimental model of gut mucosa inflammation to investigate the effects of HBO2 on HIF-1α, antioxidative enzyme, and proinflammatory cytokine genes during the colonic inflammation. Here we report that HBO2 significantly reduces severity of DSS-induced colitis, as evidenced by the clinical features, histological assessment, impaired immune cell expansion and mobilization, and reversal of IL-1β, IL-2, and IL-6 gene expression. Gene expression and antioxidative enzyme activity were changed by the HBO2 and the inflammatory microenvironment in the gut mucosa. Strong correlation of HIF-1α mRNA level to GPx1, SOD1, and IL-6 mRNA expression suggests involvement of HIF-1α in transcriptional regulation of these genes during colonic inflammation and HBO2. This is further confirmed by a strong correlation of HIF-1α with known target genes VEGF and PGK1. Results demonstrate that HBO2 has an anti-inflammatory effect in DSS-induced colitis in mice, and this effect is at least partly dependent on expression of HIF-1α and antioxidative genes.

Hyperbaric oxygenation and 20‐HETE inhibition reduce stroke volume in female diabetic Sprague–Dawley rats

What is the central question of this study? Is there a beneficial effect and what are the mechanisms of acute and multiple hyperbaric oxygenation (HBO2) exposures on the outcome of cerebral tissue injury induced by a transient middle cerebral artery occlusion model in diabetic female rats? Are 20‐hydroxyeicosatetreanoic acid and epoxyeicosatrienoic acids involved? What is the main finding and its importance? Equal reduction of cortical and total infarct size in rats treated with HBO2 and HET0016 (20‐hydroxyeicosatetreanoic acid production inhibitor) and significant mRNA upregulation of epoxyeicosatrienoic acid‐producing enzymes (Cyp2J3 and Cyp2C11) in treated groups suggest that HBO2 and HET0016 are highly effective stroke treatments and that cytochrome P450 metabolites are involved in this therapeutic effect.

Is shorter transient middle cerebral artery occlusion (t-MCAO) duration better in stroke experiments on diabetic female Sprague Dawely rats?

Abstract Aim: To determine optimal duration of transient middle cerebral artery occlusion (t-MCAO) for a stroke model in female diabetic Sprague-Dawley (SD) rats. Methods: Streptozotocin-induced type-1 diabetic SD female rats (n = 25, 12 weeks old, five groups; n = 5 per group) were subjected to different duration of t-MCAO (20, 30, 45, 60 and 90 minutes) followed by reperfusion. A control group of rats without diabetes (n = 5) was subjected to 30 minutes of t-MCAO followed by reperfusion. Twenty-four hours after reperfusion, infarct volumes were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Results: Intra-ischaemic reductions of regional cerebral blood flow (rCBF) were similar in all groups (68–75% of baseline values). Reperfusion was significantly impaired in the 90-minute ischaemia group (56–62% vs 80–125% in other groups). Twenty minutes of t-MCAO induced a small infarct (3 ± 5% of ischaemic hemisphere). Thirty minutes of ischaemia produced a significantly larger infarct (46 ± 6%). In the 45 and 60 minute groups, ischaemia infarct was 52 ± 5% and 59 ± 3% of the ischaemic hemisphere, respectively. Ischaemia of 90’ led to a massive stroke (89 ± 6% of ischaemic hemisphere encompassing the whole striatum (22 ± 3%) and almost the whole MCA irrigated cortex area (67 ± 6%)). Thirty minutes of t-MCAO did not produce stroke in the control group. Conclusion: The diabetic rat stroke model should be different from the non-diabetic, because female type-1 diabetic SD rats are highly sensitive to brain ischaemia and it is necessary to significantly shorten the duration of t-MCAO, optimally to 30 minutes.

The Effect of Dietary Intake of Omega-3 Polyunsaturated Fatty Acids on Cardiovascular Health: Revealing Potentials of Functional Food

Functional food is a food containing components that show beneficial effects on one or more body functions and improve general condition and health or significantly affect lowering of disease risks. This chapter is aimed to examine the effect of dietary intake of omega‐3 polyunsaturated fatty acids (n3‐PUFA) on cardiovascular health. This chapter presents current knowledge on functional poultry products and the reasons to consume them, omega‐3 enrichment of eggs and poultry meat, and the differences in profile of fatty acids in conventional and omega‐3–enriched eggs. The second part of the chapter focuses on the metabolism of fatty acids and effectiveness of n‐3 PUFA in the improvement of endothelial function, improvement of elasticity of the vascular wall and the anti‐inflammatory effects in patients with chronic diseases, such as metabolic syndrome, diabetes mellitus and hypercholesterolemia, and overall effect on cardiovascular health and protection. To achieve long‐term protective effects, the functional food should be consumed on daily basis. There are no specific constrains in taking functional food ; even more, it can be recommended to athletes and cardiovascular patients. General population can also benefit from eating functional food enriched with n‐3 PUFA due to their anti‐inflammatory and vascular‐protective effects.

Visfatin serum level and expression in subcutaneous and visceral adipose tissue in prepubertal boys

The biological role of visfatin in humans, especially in eutrophic and healthy children, is not understood yet, except for its link to obesity‐related disorders in adolescents and adults.

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.