Dehydroepiandrosterone protects against oxidative stress-induced endothelial dysfunction in ovariectomized rats.

Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of S˜ao Paulo, SP, Brazil.
The Journal of Physiology (Impact Factor: 4.38). 05/2011; 589(Pt 10):2585-96. DOI: 10.1113/jphysiol.2011.206078
Source: PubMed

ABSTRACT Cardiovascular disease is less frequent in premenopausal women than in age-matched men or postmenopausal women. Moreover, the marked age-related decline in serum dehydroepiandrosterone (DHEA) level has been associated to cardiovascular disease. The aim of this study was to evaluate the effects of DHEA treatment on vascular function in ovariectomized rats. At 8 weeks of age, female Wistar rats were ovariectomized (OVX) or sham (SHAM) operated and 8 weeks after surgery both groups were treated with vehicle or DHEA (10mg kg⁻¹ week⁻¹) for 3 weeks. Aortic rings were used to evaluate the vasoconstrictor response to phenylephrine (PHE) and the relaxation responses to acetylcholine (ACh) and sodium nitroprusside (SNP). Tissue reactive oxygen species (ROS) production and SOD, NADPH oxidase and eNOS protein expression were analysed. PHE-induced contraction was increased in aortic rings from OVX compared to SHAM, associated with a reduction in NO bioavailability. Furthermore, the relaxation induced by ACh was reduced in arteries from OVX, while SNP relaxation did not change. The incubation of aortic rings with SOD or apocynin restored the enhanced PHE-contraction and the impaired ACh-relaxation only in OVX. DHEA treatment corrected the increased PHE contraction and the impaired ACh-induced relaxation observed in OVX by an increment in NO bioavailability and decrease in ROS production. Besides, DHEA treatment restores the reduced Cu/Zn-SOD protein expression and eNOS phosphorylation and the increased NADPH oxidase protein expression in the aorta of OVX rats. The present results suggest an important action of DHEA, improving endothelial function in OVX rats by acting as an antioxidant and enhancing the NO bioavailability.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Rhizome of Ligusticum chuanxiong Hort. (LC), also known as Chuanxiong, is a very common herb widely used to treat cardiovascular and cerebrovascular diseases. It is also used as a major ingredient in soups for regular consumption to promote good health. To study the protective effect of LC ethanolic extract (LCEE, 600 mg/kg/day, p.o.) on the integrity of the vascular system, ovariectomized (OVX) rats were fed with a high-fat diet (HFD) plus LCEE for 12 weeks. The animal model mimics the dyslipidemic condition seen in postmenopausal women. LCEE was found to significantly reduce the body weight gain, improve serum lipid profiles (lowering total cholesterol and low density lipoprotein cholesterol but raising high density lipoprotein cholesterol) and protect vascular endothelium in the HFD-fed OVX rats. It is postulated that LCEE could provide its vascular protective effect through multiple targets by (1) improving serum lipid profiles to reduce the detrimental effects given by cholesterol; (2) reducing ROS level inside the body via enhancing hepatic anti-oxidative activity or antioxidant level to scavenge the reactive oxygen species generated in the postmenopausal hypercholestemic condition; (3) stimulating eNOS-derived nitric oxide production; and (4) counteracting the up-regulation of inflammatory cytokine (TNF-α, VCAM-1 and ICAM-1) expressions so as to reduce endothelium damage.
    07/2014; 5(10). DOI:10.1039/C4FO00211C
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background The adrenal sex hormone dehydroepiandrosterone (DHEA), which is present in serum mainly as the sulfate DHEA-S, is the most abundant steroid hormone in human blood. Its levels decline dramatically with age. Despite the great amount of literature on vascular and metabolic actions of DHEA/-S, evidence for an association between DHEA/-S levels and cardiovascular events is contradictory. Objectives This study tested the hypothesis that serum DHEA and DHEA-S are predictors of major coronary heart disease (CHD) and/or cerebrovascular disease (CBD) events in a large cohort of elderly men. Methods We used gas and liquid chromatography-mass spectrometry to analyze baseline levels of DHEA and DHEA-S in the prospective population-based Osteoporotic Fractures in Men study in Sweden (2,416 men, ages 69 to 81 years). Complete cardiovascular clinical outcomes were available from national Swedish registers. Results During the 5-year follow-up, 302 participants experienced a CHD event, and 225 had a CBD event. Both DHEA and DHEA-S levels were inversely associated with the age-adjusted risk of a CHD event; the hazard ratios and 95% confidence intervals per SD increase were 0.82 (0.73 to 0.93) and 0.86 (0.77 to 0.97), respectively. In contrast, DHEA/-S showed no statistically significant association with the risk of CBD events. The association between DHEA and CHD risk remained significant after adjustment for traditional cardiovascular risk factors, serum total testosterone and estradiol, C-reactive protein, and renal function, and remained unchanged after exclusion of the first 2.6 years of follow-up to reduce reverse causality. Conclusions Low serum levels of DHEA and its sulfate predict an increased risk of CHD, but not CBD, events in elderly men.
    Journal of the American College of Cardiology 10/2014; 64(17):1801–1810. DOI:10.1016/j.jacc.2014.05.076 · 15.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The brain has high energy requirements to maintain neuronal activity. Consequently impaired mitochondrial function will lead to disease. Normal aging is associated with several alterations in neurosteroid production and secretion. Decreases in neurosteroid levels might contribute to brain aging and loss of important nervous functions, such as memory. Up to now, extensive studies only focused on estradiol as a promising neurosteroid compound that is able to ameliorate cellular bioenergetics, while the effects of other steroids on brain mitochondria are poorly understood or not investigated at all. Thus, we aimed to characterize the bioenergetic modulating profile of a panel of seven structurally diverse neurosteroids (progesterone, estradiol, estrone, testosterone, 3α-androstanediol, DHEA and allopregnanolone), known to be involved in brain function regulation. Of note, most of the steroids tested were able to improve bioenergetic activity in neuronal cells by increasing ATP levels, mitochondrial membrane potential and basal mitochondrial respiration. In parallel, they modulated redox homeostasis by increasing antioxidant activity, probably as a compensatory mechanism to a slight enhancement of ROS which might result from the rise in oxygen consumption. Thereby, neurosteroids appeared to act via their corresponding receptors and exhibited specific bioenergetic profiles. Taken together, our results indicate that the ability to boost mitochondria is not unique to estradiol, but seems to be a rather common mechanism of different steroids in the brain. Thus, neurosteroids may act upon neuronal bioenergetics in a delicate balance and an age-related steroid disturbance might be involved in mitochondrial dysfunction underlying neurodegenerative disorders.
    Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease 09/2014; DOI:10.1016/j.bbadis.2014.09.013 · 5.09 Impact Factor

Full-text (2 Sources)

Available from
May 20, 2014