Nitroso-redox status and vascular function in marginal and severe ascorbate deficiency.

Unlabelled: Marginal vitamin C (ascorbic acid) deficiency is a prevalent yet underappreciated risk factor for cardiovascular disease. Along with glutathione, ascorbate plays important roles in antioxidant defense and redox signaling. Production of nitric oxide (NO) and reactive oxygen species and their interaction, giving rise to nitroso and nitrosyl product formation, are key components of the redox regulation/signaling network.

An integrated approach to assessing nitroso-redox balance in systemic inflammation.

Most studies examining the metabolic fate of NO during systemic inflammation have focused on measuring the quantitatively predominating, stable anions nitrite and nitrate within the circulation. However, these are not necessarily the NO-related products that govern NO metabolism and signaling in tissues. We assessed all major NO derivatives temporally in blood and vital organs during inflammation and explored their relationship to insult severity and redox status.

Tissue processing of nitrite in hypoxia: an intricate interplay of nitric oxide-generating and -scavenging systems.

Although nitrite (NO(2)(-)) and nitrate (NO(3)(-)) have been considered traditionally inert byproducts of nitric oxide (NO) metabolism, recent studies indicate that NO(2)(-) represents an important source of NO for processes ranging from angiogenesis through hypoxic vasodilation to ischemic organ protection. Despite intense investigation, the mechanisms through which NO(2)(-) exerts its physiological/pharmacological effects remain incompletely understood. We sought to systematically investigate the fate of NO(2)(-) in hypoxia from cellular uptake in vitro to tissue utilization in vivo using the Wistar rat as a mammalian model.

Nitrite is a signaling molecule and regulator of gene expression in mammalian tissues.

Mammalian tissues produce nitric oxide (NO) to modify proteins at heme and sulfhydryl sites, thereby regulating vital cell functions. The majority of NO produced is widely assumed to be neutralized into supposedly inert oxidation products including nitrite (NO2(-)). Here we show that nitrite, also ubiquitous in dietary sources, is remarkably efficient at modifying the same protein sites, and that physiological nitrite concentrations account for the basal levels of these modifications in vivo.

Effects of chronic quercetin treatment in experimental renovascular hypertension.

The aims of the present study were to analyse the effects of an oral daily dose (10 mg/kg) of the dietary flavonoid quercetin for five weeks in two-kidney, one-clip (2K1C) Goldblatt (GB) hypertensive rats. The evolution of systolic blood pressure was followed by weekly measurements, and morphological variables, proteinuria, plasma nitrates plus nitrites (NOx) and thiobarbituric acid reactive substances (TBARS), liver oxidative stress markers and endothelial function were determined at the end of the experimental period. Quercetin treatment reduced systolic blood pressure of GB rats, producing no effect in control animals.

Effects of the dietary flavonoid chrysin in isolated rat mesenteric vascular bed.

In the present study, the effects of the bioflavonoid chrysin (5,7-dihydroxyflavone) were analyzed on the perfusion pressure of isolated mesenteric vascular bed. The vasorelaxant effects of chrysin were more potent on intact endothelium than on denuded vessels. This endothelium-dependent response induced by chrysin was inhibited in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME), KCl, tetraethylammonium (TEA), BaCl(2), TEA plus L-NAME, and ouabain plus BaCl(2), while incubations with indomethacin and glibenclamide did not modify the response induced by this bioflavonoid.

Effects of chronic quercetin treatment on antioxidant defence system and oxidative status of deoxycorticosterone acetate-salt-hypertensive rats.

We investigated the potential of chronic administration of an oral daily dose (10 mg/kg) of the dietary flavonoid quercetin to prevent hypertension and oxidative stress induced by deoxycorticosterone acetate (DOCA)-salt in rats. We have compared its effects to those produced by the well-known anti-hypertensive drug verapamil, administered orally (20 mg/kg/day). Quercetin and verapamil treatments reduced systolic blood pressure of DOCA-salt rats in approximately 67.

Effects of quercetin treatment on vascular function in deoxycorticosterone acetate-salt hypertensive rats. Comparative study with verapamil.

This study analysed and compared the effects of chronic oral treatment with quercetin or verapamil on systolic blood pressure and vascular function in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Quercetin and verapamil inhibited the development of DOCA-salt-induced hypertension in a similar manner. DOCA-salt-hypertensive rats showed potassium depletion and oxidative stress, prevented only by concomitant quercetin administration.

Effects of chronic chrysin treatment in spontaneously hypertensive rats.

The effects of an oral daily dose (20 mg kg(-1)) of the flavonoid chrysin for 6 weeks in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto rats (WKY) were analysed. Chrysin reduces SHR elevated blood pressure, cardiac hypertrophy and functional vascular changes, but is without effect in WKY. These protective effects were associated with a reduced oxidative status due to the antioxidant properties of the drug.