Carnosine is a dipeptide synthesized in the body from β-alanine and L-histidine. It is found in high concentrations in the brain, muscle, and gastrointestinal tissues of humans and is present in all vertebrates. Carnosine has a number of beneficial antioxidant properties. For example, carnosine scavenges reactive oxygen species (ROS) as well as alpha-beta unsaturated aldehydes created by peroxidation of fatty acid cell membranes during oxidative stress. Carnosine can oppose glycation, and it can chelate divalent metal ions. Carnosine alleviates diabetic nephropathy by protecting podocyte and mesangial cells, and can slow down aging. Its component, the amino acid beta-alanine, is particularly interesting as a dietary supplement for athletes because it increases muscle carnosine, and improves effectiveness of exercise and stimulation and contraction in muscles. Carnosine is widely used among athletes in the form of supplements, but rarely in the population of cardiovascular or diabetic patients. Much less is known, if any, about its potential use in enriched food. In the present review, we aimed to provide recent knowledge on carnosine properties and distribution, its metabolism (synthesis and degradation), and analytical methods for carnosine determination, since one of the difficulties is the measurement of carnosine concentration in human samples. Furthermore, the potential mechanisms of carnosine’s biological effects in musculature, metabolism and on immunomodulation are discussed. Finally, this review provides a section on carnosine supplementation in the form of functional food and potential health benefits and up to the present, neglected clinical use of carnosine.

This study aimed to test the effect of n-3 polyunsaturated fatty acid (PUFA)-enriched hen egg consumption on serum lipid and free fatty acid profiles, inflammatory and oxidative stress biomarkers, and microvascular reactivity in patients with coronary artery disease (CAD). Forty CAD patients participated in this study. Of those, 20 patients had acute CAD (Ac-CAD), and 20 patients had chronic CAD (Ch-CAD). The control group (N = 20) consumed three regular hen eggs/daily (249 mg n-3 PUFAs/day), and the n-3 PUFAs group (N = 20) consumed three n-3 PUFA-enriched hen eggs/daily (1053 g n-3 PUFAs/day) for 3 weeks. Serum n-3 PUFA concentration significantly increased (in all CAD patients), while LDL cholesterol and IL-6 (in Ac-CAD patients), and hsCRP and IL-1a (in all CAD patients) significantly decreased in the n-3 PUFAs group. Glutathione peroxidase (GPx) activity significantly decreased, and forearm skin microvascular reactivity in response to vascular occlusion (postocclusive reactive hyperemia (PORH)) remained unchanged in both the n-3 PUFAs and control groups in total CAD, Ac-CAD, and Ch-CAD patients. Potentially, n-3 PUFA-enriched hen eggs can change the free fatty acid profile to a more favorable lower n6/n3 ratio, and to exhibit mild anti-inflammatory effects but not to affect microvascular reactivity in CAD patients.

High salt (HS) dietary intake leads to impaired vascular endothelium-dependent responses to various physiological stimuli, some of which are mediated by arachidonic acid (AA) metabolites. Transgenic Tff3−/− gene knockout mice (Tff3−/−/C57BL/6N) have changes in lipid metabolism which may affect vascular function and outcomes of stroke. We aimed to study the effects of one week of HS diet (4% NaCl) on vascular function and stroke induced by transient occlusion of middle cerebral artery in Tff3−/− and wild type (WT/C57BL/6N) mice. Flow-induced dilation (FID) of carotid artery was reduced in WT-HS mice, but not affected in Tff3−/−-HS mice. Nitric oxide (NO) mediated FID. NO production was decreased with HS diet. On the contrary, acetylcholine-induced dilation was significantly decreased in Tff3−/− mice on both diets and WT-HS mice. HS intake and Tff3 gene depletion affected the structural components of the vessels. Proteomic analysis revealed a significant effect of Tff3 gene deficiency on HS diet-induced changes in neuronal structural proteins and acute innate immune response proteins’ expression and Tff3 depletion, but HS diet did not increase the stroke volume, which is related to proteome modification and upregulation of genes involved mainly in cellular antioxidative defense. In conclusion, Tff3 depletion seems to partially impair vascular function and worsen the outcomes of stroke, which is moderately affected by HS diet.

This study aimed to determine the mechanosensing role of angiotensin II type 1 receptor (AT1R) in flow-induced dilation (FID) and oxidative stress production in middle cerebral arteries (MCA) of Sprague-Dawley rats. Eleven-weeks old, healthy male Sprague-Dawley rats on a standard diet were given the AT1R blocker losartan (1 mg/mL) in drinking water (losartan group) or tap water (control group) ad libitum for 7 days. Blockade of AT1R attenuated FID and acetylcholine-induced dilations was compared to control group. Nitric oxide (NO) synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) and cyclooxygenase inhibitor indomethacin (INDO) significantly reduced FID in control group. The attenuated FID in losartan group was further reduced by INDO only at ∆100 mmHg, whereas L-NAME had no effect. In losartan group, TEMPOL (a superoxide scavenger) restored dilatation, while TEMPOL+L-NAME together significantly reduced FID compared to restored dilatation with TEMPOL alone. Direct fluorescence measurements of NO and reactive oxygen species (ROS) production in MCA, in no-flow conditions revealed significantly reduced vascular NO levels with AT1R blockade compared to control group, while flow increased the NO and ROS production in losartan group and had no effect in control group. In losartan group, TEMPOL decreased ROS production in both no-flow and flow conditions. AT1R blockade elicited increased serum concentrations of AngII, 8-iso-PGF2α, and TBARS, and decreased antioxidant enzyme activity (SOD and CAT). These results suggest that in small isolated cerebral arteries: 1) AT1 receptor maintains dilations in physiological conditions; 2) AT1R blockade leads to increased vascular and systemic oxidative stress, which underlies impaired FID.

Objective: Salt-induced suppression of angiotensin II contributes to impaired endothelium-dependent vascular reactivity. The present study investigated the effect of chronic low-dose angiotensin II (ANG II) supplementation on the mechanisms of flow-induced dilation (FID) and oxidative stress at the cellular and molecular level in middle cerebral arteries (MCA) of male Sprague-Dawley rats fed high salt diet.Methods: Rats (10 weeks old) were randomly assigned to a low salt diet group (0.4% NaCl in rat chow); high salt diet group (7 days 4% NaCl in rat chow) or HSRANG II group [7 days high salt diet with 3 days ANG II administration via osmotic minipumps (100 ng/kg per min on days 4-7)]. FID was determined in absence/presence of the NOS inhibitor L-NAME, the non-selective cyclooxygenase (COX-1,2) inhibitor indomethacin, a selective inhibitor of CYP450 epoxygenase activity (MS-PPOH) and the superoxide dismutase mimetic TEMPOL. Gene expression of antioxidative enzymes, and of genes and proteins involved in FID mechanisms were determined by RT-qPCR and western blot. Vascular nitric oxide and superoxide/reactive oxygen species levels were assessed by direct fluorescence. Serum systemic oxidative stress parameters were measured by spectrophotometry.Results: Chronic low-dose ANG II supplementation in high salt fed rats restored FID of MCAs, which was nitric oxide, prostanoid and epoxyeicosatrienoic acid dependent. ANG II changed the protein/gene expression of COXs, HIF-1a and VEGF and significantly increased GPx4 and EC-SOD antioxidative enzyme expression, decreased systemic oxidative stress, decreased superoxide/ROS levels and increased nitric oxide bioavailability in the vascular wall. Conclusion:Physiological levels of circulating ANG II are crucial to maintain the HIF-1a dependent mechanisms of FID and vascular oxidative balance without affecting mean arterial pressure.