Antioxidant activities of estrogens against aqueous and lipophilic radicals; differences between phenol and catechol estrogens

Oxidative balance score and associations with dyslipidemia and mortality among US adults: A mortality follow-up study of a cross-sectional cohort

BACKGROUND

Oxidative stress has been implicated in the pathogenesis and progression of dyslipidemia. We aimed to investigate the association between the oxidative balance score, and dyslipidemia, as well as to assess the mortality risk associated with oxidative balance score in patients with dyslipidemia.

METHODS

We performed a mortality follow-up study of a cross-sectional cohort of 26,118 adults from the National Health and Nutrition Examination Survey 1999-2018. The total oxidative balance score was calculated by 16 dietary nutrients (dietary oxidative balance score) and four lifestyle factors (lifestyle oxidative balance score). Weighted Cox proportional hazard model was applied to determine the relationship between oxidative balance score and all-cause or cardiovascular disease (CVD) mortality within the dyslipidemia group.

RESULTS

During a median follow-up of 118 months, 2448 all-cause deaths (766 CVD-related) occurred. A significant negative correlation was observed between total oxidative balance score, dietary oxidative balance score, lifestyle oxidative balance score, and dyslipidemia. The multivariable-adjusted odds ratios and 95% CIs for dyslipidemia were 0.86 (0.77-0.97), 0.80 (0.72-0.91), and 0.63 (0.56-0.70), respectively, when comparing the second, third, and fourth quartiles of total oxidative balance score to the reference lowest quartile (P for trend <0.0001). Increasing total oxidative balance score was inversely associated with all-cause (hazard ratio [HR] = 0.98, 95% CI 0.98-0.99) and CVD-specific mortality (HR = 0.98, 95% CI 0.97-0.99) in participants with dyslipidemia.

CONCLUSIONS

Oxidative balance score is inversely associated with dyslipidemia and linked to all-cause and CVD-related mortality, highlighting the potentially protective role of an antioxidant-rich diet against dyslipidemia.

The Role of Lifestyle and Dietary Factors in the Development of Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is a condition that arises from dysfunction or early depletion of the ovarian follicle pool accompanied by an earlier-than-normal loss of fertility in young women. Oxidative stress has been suggested as an important factor in the decline of fertility in women and POI. In this review, we discuss the mechanisms of oxidative stress implicated in ovarian ageing and dysfunction in relation to POI, in particular mitochondrial dysfunction, apoptosis and inflammation. Genetic defects, autoimmunity and chemotherapy, are some of the reviewed hallmarks of POI that can lead to increased oxidative stress. Additionally, we highlight lifestyle factors, including diet, low energy availability and BMI, that can increase the risk of POI. The final section of this review discusses dietary factors associated with POI, including consumption of oily fish, mitochondria nutrient therapy, melatonin, dairy and vitamins that can be targeted as potential interventions, especially for at-risk women and in combination with personalised nutrition. Understanding the impact of lifestyle and its implications for POI and oxidative stress holds great promise in reducing the burden of this condition.

Oxidant-antioxidant balance in girls with precocious puberty: a case-control study

This case-control study aims to evaluate the oxidant-antioxidant balance in girls having central precocious puberty (CPP) and premature thelarche (PT). Thirty-four girls having CPP, 24 girls having PT, and 49 healthy growing girls between 7 and 9 years of age admitted to child health supervision were enrolled. Total antioxidant and oxidant capacity, myeloperoxidase, catalase, superoxide dismutase, total thiol, native thiol, and disulfide levels were analyzed in serum samples. Low total oxidant status (<12.0) was found to be highest in the CPP group, lowest in the control group, and the PT group was in between them. After controlling bone age and z score for body mass index, generalized linear models revealed lower oxidative stress index values in the CPP and the PT groups than the control group. Other studied parameters did not differ among groups. Precocious puberty in girls is associated with some changes in the oxidant-antioxidant status.

Dietary transference of 17α-ethinylestradiol changes the biochemical and behavioral biomarkers in adult zebrafish (Danio rerio)

The endocrine disruptors (ED), even in low concentration, can change the homeostasis of an organism through the biochemical and physiological pathways; and are gaining more relevance due to their well-reported presence in the natural environment. EDs mainly affect non-target animals, which can bioaccumulate, leading to changes in metabolism. Another problem is due to several organisms that compose the aquatic biota serving as a basis of the food chain and transferring it to higher trophic levels. Here we evaluated the dietary transference of 17α-ethinylestradiol (EE2), in adult zebrafish chronically fed by EE2-bioaccumulated brine shrimp (BS). For this, we evaluated behavioral biomarkers such as the novel tank test (NTT), social preference test (SPT), mirror-induced aggressivity (MIA), and biochemical biomarkers such as acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CTL), and glutathione-S-transferase (GST) activity, cortisol, and lipid peroxidation levels in adult zebrafish. The behavioral effects can be explained by the changed effects on acetylcholinesterase activity as well as in the antioxidant system mainly affected by the high levels of EE2 identified by HPLC shown that had occurred during a dietary transfer for fish. EE2 has a potential pattern for bioaccumulation and dietary transfer in biological tissue and EE2 can affect the behavior of fish. The observed effects could be dangerous to the environment, affecting, other animals and even human health.

Factors Influencing Skin Aging and the Important Role of Estrogens and Selective Estrogen Receptor Modulators (SERMs)

The narrative for this overview focuses on updating the factors that influence skin aging and the important role estrogens and selective estrogen receptor modulators (SERMs) play in this process (mainly utilizing journal reports and reviews from the last four years). Estrogens have been known and studied for over a century. For many years, it has been recognized that estrogens are important in the maintenance of human skin. Women seek cosmetic and medical treatments to improve dermal health and physical characteristics to enhance their self-perception and inhibit skin aging, particularly in highly visible body areas. The goal: to retain estrogen’s positive benefits while aging and especially at/after menopause where estrogen-deficient skin contributes to the dramatic decline in skin health. In this overview, both background information and recent novel findings are included that cover aging (general mechanisms), skin aging, and factors that influence skin aging (intrinsic, extrinsic, skin microbiome and gut microbiome.) Plus, estrogen’s general role in maintaining skin health is presented through the classical estrogen receptors alpha (α) and beta (β) and non-classical (or non-genomic) estrogen receptor (G protein-coupled seven transmembrane receptor). More importantly, the various benefits of 17β-estradiol in skin health are examined (ie, skin collagen and elastin profiles that follow 17β-estradiol levels during aging and at/after menopause). Finally, a revision of information for estrogenic skin topical applications involving isoflavonoid compounds that act as SERMs, but are classified as endocrine disruptors, and a topical estrogen analog are explored to update the known and unknown characteristics of these treatments. Further study is warranted to understand the biological and molecular mechanisms by which estrogens support and enhance dermal health and wellbeing.

Salt Sensitivity of Blood Pressure in Blacks and Women: A Role of Inflammation, Oxidative Stress, and Epithelial Na+ Channel

Significance: Salt sensitivity of blood pressure (SSBP) is an independent risk factor for mortality and morbidity due to cardiovascular disease, and disproportionately affects blacks and women. Several mechanisms have been proposed, including exaggerated activation of sodium transporters in the kidney leading to salt retention and water. Recent Advances: Recent studies have found that in addition to the renal epithelium, myeloid immune cells can sense sodium via the epithelial Na+ channel (ENaC), which leads to activation of the nicotinamide adenine dinucleotide phosphate oxidase enzyme complex, increased fatty acid oxidation, and production of isolevuglandins (IsoLGs). IsoLGs are immunogenic and contribute to salt-induced hypertension. In addition, aldosterone-mediated activation of ENaC has been attributed to the increased SSBP in women. The goal of this review is to highlight mechanisms contributing to SSBP in blacks and women, including, but not limited to increased activation of ENaC, fatty acid oxidation, and inflammation. Critical Issues: A critical barrier to progress in management of SSBP is that its diagnosis is not feasible in the clinic and is limited to expensive and laborious research protocols, which makes it difficult to investigate. Yet without understanding the underlying mechanisms, this important risk factor remains without treatment. Future Directions: Further studies are needed to understand the mechanisms that contribute to differential blood pressure responses to dietary salt and find feasible diagnostic tools. This is extremely important and may go a long way in mitigating the racial and sex disparities in cardiovascular outcomes. Antioxid. Redox Signal. 35, 1477-1493.

Role of Polyphenols in the Metabolism of the Skeletal System in Humans and Animals – A Review

Polyphenols are a group of compounds arousing enormous interest due to their multiple effects on both human and animal health and omnipresence in plants. A number of in vitro and animal model studies have shown that all polyphenols exhibit anti-inflammatory and antioxidant activities, and play a significant role against oxidative stress-related pathologies. They also exert gut promotory effects and prevent chronic degenerative diseases. However, less attention has been paid to the potential influence of polyphenols on bone properties and metabolism. It is well known that proper growth and functioning of the organism depend largely on bone growth and health. Therefore, understanding the action of substances (including polyphenols) that may improve the health and functioning of the skeletal system and bone metabolism is extremely important for the health of the present and future generations of both humans and farm animals. This review provides a comprehensive summary of literature related to causes of bone loss during ageing of the organism (in both humans and animals) and possible effects of dietary polyphenols preventing bone loss and diseases. In particular, the underlying cellular and molecular mechanisms that can modulate skeletal homeostasis and influence the bone modeling and remodeling processes are presented.

Menopause and the Skin: Old Favorites and New Innovations in Cosmeceuticals for Estrogen-Deficient Skin

Estrogen is a pivotal signaling molecule; its production is regulated by the expression of the aromatase (CYP19A1) gene from ovarian and peripheral tissue sites, and it is transmitted via estrogen receptors to influence many important biological functions. However, the narrative for this overview focuses on the decline of 17β-estradiol levels from ovarian sites after menopause. This estrogen-deficient condition is associated with a dramatic reduction in skin health and wellness by negatively impacting dermal cellular and homeostatic mechanisms, as well as other important biological functions. The changes include loss of collagen, elastin, fibroblast function, vascularity, and increased matrix metalloproteinase(s) enzymatic activities, resulting in cellular and extracellular degradation that leads to dryness, wrinkles, atrophy, impaired wound healing/barrier function, decreased antioxidant capacity [i.e., defense against reactive oxygen species (ROS) and oxidative stress], decreased attractiveness and psychological health, and increased perception of aging. While topical estrogen may reverse these changes, the effects of today's low-dose systemic hormone treatments are not well established, raising the need for more concentrated local administration of hormones or newer cosmeceutical agents such as selective estrogen receptor modulators (SERMs), including phytoestrogens that have become major active ingredients for skin care products, especially when addressing estrogen-deficient skin. Two example compounds are presented, an analog of resveratrol (i.e., 4'-acetoxy resveratrol) and the isoflavonoid equol, both of which are involved in a variety of biochemical/molecular actions and mechanisms, as demonstrated via in vitro and clinical studies that enhance human dermal health, especially in estrogen-deficient skin.

Nutraceutical based SIRT3 activators as therapeutic targets in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, and its incidence is increasing worldwide with increased lifespan. Currently, there is no effective treatment to cure or prevent the progression of AD, which indicates the need to develop novel therapeutic targets and agents. Sirtuins, especially SIRT3, a mitochondrial deacetylase, are NAD-dependent histone deacetylases involved in aging and longevity. Accumulating evidence indicates that SIRT3 dysfunction is strongly associated with pathologies of AD, hence, therapeutic modulation of SIRT3 activity may be a novel application to ameliorate the pathologies of AD. Natural products commonly used in traditional medicine have wide utility and appear to have therapeutic benefits for the treatment of neurodegenerative diseases such as AD. The present review summarizes the currently available natural SIRT3 activators and their potentially neuroprotective molecular mechanisms of action that make them a promising agent in the treatment and management of neurodegenerative diseases such as AD.

Copper-assisted oxidation of catechols into quinone derivatives

Catechols are ubiquitous substances often acting as antioxidants, thus of importance in a variety of biological processes. The Fenton and Haber–Weiss processes are thought to transform these molecules into aggressive reactive oxygen species (ROS), a source of oxidative stress and possibly inducing degenerative diseases. Here, using model conditions (ultrahigh vacuum and single crystals), we unveil another process capable of converting catechols into ROSs, namely an intramolecular redox reaction catalysed by a Cu surface. We focus on a tri-catechol, the hexahydroxytriphenylene molecule, and show that this antioxidant is thereby transformed into a semiquinone, as an intermediate product, and then into an even stronger oxidant, a quinone, as final product. We argue that the transformations occur via two intramolecular redox reactions: since the Cu surface cannot oxidise the molecules, the starting catechol and the semiquinone forms each are, at the same time, self-oxidised and self-reduced. Thanks to these reactions, the quinone and semiquinone are able to interact with the substrate by readily accepting electrons donated by the substrate. Our combined experimental surface science and ab initio analysis highlights the key role played by metal nanoparticles in the development of degenerative diseases.

An antioxidant catechol transforms following intramolecular redox reactions into highly reactive oxygen species, a semiquinone and a quinone, on copper.

Estrogen-related mechanisms in sex differences of hypertension and target organ damage

Hypertension (HTN) is a primary risk factor for cardiovascular (CV) events, target organ damage (TOD), premature death and disability worldwide. The pathophysiology of HTN is complex and influenced by many factors including biological sex. Studies show that the prevalence of HTN is higher among adults aged 60 and over, highlighting the increase of HTN after menopause in women. Estrogen (E2) plays an important role in the development of systemic HTN and TOD, exerting several modulatory effects. The influence of E2 leads to alterations in mechanisms regulating the sympathetic nervous system, renin-angiotensin-aldosterone system, body mass, oxidative stress, endothelial function and salt sensitivity; all associated with a crucial inflammatory state and influenced by genetic factors, ultimately resulting in cardiac, vascular and renal damage in HTN. In the present article, we discuss the role of E2 in mechanisms accounting for the development of HTN and TOD in a sex-specific manner. The identification of targets with therapeutic potential would contribute to the development of more efficient treatments according to individual needs.

Inhibitory mechanism of 17β-aminoestrogens in the formation of Aβ aggregates

Alzheimer's disease (AD) is a complex neurodegenerative disorder associated with the aggregation of the amyloid-beta peptide (Aβ) into large oligomers and fibrils that damage healthy brain cells. The predominant peptide fragments in the plaques are mainly formed by the Aβ_1-40 and Aβ_1-42 peptides, albeit the eleven-residue Aβ_25-35 segment is largely used in biological studies because it retains the neurotoxic properties of the longer Aβ peptides. Recent studies indicate that treatment with therapeutic steroid hormones reduces the progress of the disease in AD models. Particularly, treatment with 17β-aminoestrogens (AEs) has shown a significant alleviation of the AD development by inhibiting oxidative stress and neuronal death. Yet, the mechanism by which the AE molecules exhibit their beneficial effects remains speculative. To shed light into the molecular mechanism of inhibition of the AD development by AEs, we investigated the possibility of direct interaction with the Aβ_25-35 peptide. First, we calculate various interacting electronic properties of three AE derivatives as follows: prolame, butolame, and pentolame by performing DFT calculations. To account for the polymorphic nature of the Aβ aggregates, we considered four different Aβ_25-35 systems extracted from AD relevant fibril structures. From the calculation of different electron density properties, specific interacting loci were identified that guided the construction and optimization of various complexes. Interestingly, the results suggest a similar inhibitory mechanism based on the direct interaction between the AEs and the M35 residue that seems to be general and independent of the polymorphic properties of the Aβ aggregates. Our analysis of the complex formation provides a structural framework for understanding the AE therapeutic properties in the molecular inhibitory mechanism of Aβ aggregation.

Spectroscopic investigation and computational studies on the interaction of Acriflavine with various estrogens

The fluorescence quenching of Acriflavine (AFN) by certain estrogens was examined in aqueous media by employing steady state and time-resolved fluorescence measurements. The absorption spectra of AFN change with significant bathochromic shift in presence of quencher molecules. The quenching behavior was examined by correlating the bimolecular quenching rate constant (k_q) with the free energy change (ΔG). The decrease in quenching rate constant depends on the increase in oxidation potential of quencher molecules. The fluorescence quenching experiments were carried out in different solvents of varying polarities and reveals the possibility of charge transfer quenching mechanism. Lifetime measurements indicate static quenching. The quenching behavior is addressed from bond dissociation enthalpy (BDE) calculations. The antioxidant activity of estrogen compounds were evaluated by deoxyribose oxidation assay.

Gender differences in mRNA expression of aquaporin 8 and glutathione peroxidase in cataractous lens following intake of an antioxidant supplement

Antioxidants can decrease oxidative damage and prevent age-related ocular disease. Our previous investigation on human aqueous humor following intake of a lutein-containing antioxidant supplement reported an increase in the scavenging activity of superoxide in both genders and an increase in the amount of hydrogen peroxide (H₂O₂) in females. Aquaporin 8 (AQP8) is a diffusion facilitator of H₂O₂ and glutathione peroxidase (Gpx) is a H₂O₂ scavenging enzyme. The correlation between AQP8 and Gpx may be the key to determining how oxidative stress in the aqueous humor affects the lens after intake of antioxidant supplements. In this study, 24 patients with the same grade of binocular cataract were included. Anterior capsule samples, including lens epithelial cells (LECs), were collected during cataract surgery before (as pre-intake samples) and after 6 weeks of oral intake of Ocuvite Lutein ^® (as post-intake samples). The mRNA expression of APQ8 and Gpx was measured using real-time polymerase chain reaction. Among males, AQP8 expression decreased significantly after the supplementation (P = .03), while there was no statistical change among females. AQP8 expression was significantly correlated to that of Gpx in post-intake samples among females (R = 0.69, P = .02), while no correlation was evident among males. The results suggest antioxidant supplementation may work by different mechanisms on LECs between genders. After supplementation, a decrease in AQP8 in LECs may inhibit the influx of H₂O₂ from the aqueous humor in males. In females however, the correlation between AQP8 and Gpx in LECs may indicate an increase in Gpx activity following the influx of H₂O₂ from the aqueous humor and further scavenging of H₂O₂.

Estrogen-mediated protection of the organotin-degrading strain Metarhizium robertsii against oxidative stress promoted by monobutyltin

Dibutyltin (DBT) is a global pollutant characterized by pro-oxidative properties. The fungal strain Metarhizium robertsii can eliminate high levels of DBT efficiently. In this study, induction of oxidative stress as well as its alleviation through the application of natural estrogens during the elimination of DBT by M. robertsii were evaluated. During the first 24 h of incubation, the initial concentration of DBT (20 mg l^-1) was reduced to 3.1 mg l^-1, with simultaneous formation of a major byproduct - monobutyltin (MBT). In the presence of estrone (E1) or 17β-estradiol (E2), the amounts of dibutyltin residues in the fungal cultures were found to be approximately 2-fold higher compared to cultures without estrogens, which was associated with the simultaneous utilization of the compounds by cytochrome P450 enzymes. On the other hand, MBT levels were approximately 2.5 times lower in the fungal cultures with the addition of one of the estrogens. MBT (not DBT) promotes the generation of O₂^-, H₂O₂, and NO at levels 65.89 ± 18.08, 4.04 ± 3.62, and 27.92 ± 1.95, respectively. Superoxide dismutase and catalase activities did not show any response of the M. robertsii strain against the overproduction of superoxide anion and hydrogen peroxide. Application of E1 as well as E2 ensured non-enzymatic defense against nitrosative and oxidative stress through scavenging of nitrogen and oxygen reactive species, and limited their levels from 1.5-fold to 21-fold, depending on the used estrogen.

Vascular Aging: Implications for Cardiovascular Disease and Therapy

The incidence and prevalence of cardiovascular disease is highest among the elderly, in part, due to deleterious effects of advancing age on the heart and blood vessels. Aging, a known cardiovascular risk factor, is progressively associated with structural and functional changes to the vasculature including hemodynamic disturbance due to increased oxidative stress, premature cellular senescence and impairments in synthesis and/or secretion of endothelium-derived vasoactive molecules. These molecular and physiological changes lead to vessel wall stiffening and thickening, as well as other vascular complications that culminate to loss of vascular tone regulation and endothelial function. Intriguingly, the vessel wall, a biochemically active structure composed of collagen, connective tissue, smooth muscle and endothelial cells, is adversely affected by processes involved in premature or normal aging. Notably, the inner most layer of the vessel wall, the endothelium, becomes senescent and dysfunctional with advancing age. As a result, its ability to release vasoactive molecules such as acetylcholine (ACh), prostacyclin (PGI2), endothelium-derived hyperpolarizing factor (EDHF), and nitric oxide (NO) is reduced and the cellular response to these molecules is also impaired. By contrast, the vascular endothelium increases its generation and release of reactive oxygen (ROS) and nitrogen (RNS) species, vasoconstrictors such as endothelin (ET) and angiotensin (AT), and endogenous inhibitors of NO synthases (NOSs) to block NO. This skews the balance of the endothelium in favor of the release of highly tissue reactive and harmful molecules that promote DNA damage, telomere erosion, senescence, as well as stiffened and hardened vessel wall that is prone to the development of hypertension, diabetes, atherosclerosis and other cardiovascular risk factors. This Review discusses the impact of advancing age on cardiovascular health, and highlights the cellular and molecular mechanisms that underlie age-associated vascular changes. In addition, the role of pharmacological interventions in preventing or delaying age-related cardiovascular disease is discussed.

Resistance or aerobic training decreases blood pressure and improves cardiovascular autonomic control and oxidative stress in hypertensive menopausal rats

We investigated whether resistance training (RT) vs. aerobic training (AT) differentially impacts on arterial pressure and related mechanisms in ovariectomized spontaneously hypertensive rats (SHRs). Female SHRs were ovariectomized and assigned to one of the following groups: sedentary, AT, or RT; sham sedentary SHR were used as control group. AT was performed on a treadmill, whereas RT was performed on a vertical ladder. Both exercise protocols were performed for 8 wk, 5 days/wk. Arterial pressure, baroreflex sensitivity, autonomic modulation, and cardiac oxidative stress parameters (lipid peroxidation, protein oxidation, redox balance, NADPH oxidase, and antioxidant enzymes activities) were analyzed. Ovariectomy increased mean arterial pressure (∼9 mmHg), sympathetic modulation (∼40%), and oxidative stress in sedentary rats. Both RT and AT reduced mean arterial pressure (∼20 and ∼8 mmHg, respectively) and improved baroreflex sensitivity compared with sedentary ovariectomized rats. However, RT-induced arterial pressure decrease was significantly less pronounced than AT. Lipid peroxidation and protein oxidation were decreased while antioxidant enzymes were increased in both trained groups vs. sedentaries. The reduced gluthatione was higher after AT vs. other groups, whereas oxidized gluthatione was lower after RT vs. AT. Moreover, sympathetic and parasympathetic modulations were highly correlated with cardiac oxidative stress parameters. In conclusion, both RT and AT can decrease arterial pressure in a model of hypertension and menopause; although, at different magnitudes this decrease was related to attenuated autonomic dysfunction in association with cardiac oxidative stress improvement in both exercise protocols.

Relationship between serum DHEAS and oxidative stress levels of body mass index in healthy postmenopausal women

OBJECTIVES

Menopause is a natural step in the process of aging. Postmenopausal women have decreased levels of antioxidants and increased oxidative stress, the latter of which plays an important role in atherogenesis. The aim of the present study was to evaluate the relationship of the body mass index (BMI) with serum catalase activity, malondialdehyde (MDA), and dehydroepiandrosterone sulfate (DHEAS) levels in healthy postmenopausal women and estimate whether the MDA/DHEAS ratio is a possible marker of oxidative stress for determining cardiovascular risk in these women.

METHODS

We investigated serum catalase activity, MDA, and DHEAS levels, parity history, age, and BMI in 96 healthy postmenopausal women aged 50-82 years. The serum MDA levels and catalase activity were measured spectrophotometrically. The serum DHEAS levels were measured using an enzyme-linked immunosorbent assay. The ratio percentage of the serum DHEAS levels to serum MDA levels was designated as a biomarker for oxidative stress.

RESULTS

The mean BMI of the patients was 31.72 ± 6.16 kg/m(2) (range = 20.5-47.94). The MDA/DHEAS ratio was significantly decreased in patients with a BMI over 30 compared to that of patients with a BMI between 25 and 30 (P = 0.025). Moreover, BMI was positively correlated with serum DHEAS levels (r = 0.285, P < 0.01) and negatively correlated with the MDA/DHEAS ratio (r = -0.241, P < 0.05) in postmenopausal women. Furthermore, BMI was observed to be a potential predictor of the MDA/DHEAS ratio based on covariance analysis (P = 0.039).

CONCLUSIONS

Our results indicate that healthy, obese, postmenopausal women have a decreased MDA/DHEAS ratio. Additionally, BMI was observed to be a potential predictor of the MDA/DHEAS ratio.

Increased Expression of Interleukin-18 in Lenses of Ovariectomized Rats

Previous studies showed an increased prevalence of cataracts in postmenopausal women. In this study, we investigated changes in the levels of calcium ion (Ca(2+)) and interleukin (IL)-18, which are factors in cataract development, in the lenses of ovariectomized (OVX) rats, a model of postmenopausal woman. Although the Ca(2+) content in the blood of OVX rats increased 1 month after ovariectomy and subsequently decreased, the Ca(2+) content in the lenses was unchanged in OVX rats 1-3 months after ovariectomy. The Ca(2+)-ATPase activity in the lenses of OVX rats peaked 1 month after ovariectomy, and the behavior of Ca(2+)-ATPase activity in lenses of OVX rats was similar to that of the Ca(2+) concentration in the blood. It is possible that hypercalcemia increases the Ca(2+) inflow into the lens; however, the enhanced Ca(2+)-ATPase activity prevents the Ca(2+) level from rising. On the other hand, we found that the levels of both IL-18 and interferon (IFN)-γ in the lenses of OVX rats were significantly increased as compared with the lenses of sham (control) rats during the period 1-3 months after surgery. These results suggest that the expression of IFN-γ via IL-18 in the lenses of OVX rats is induced by ovariectomy, and that excessive IL-18 and IFN-γ production in the lenses may be related to cataract development in postmenopausal women. These findings support those of previous studies that assessed lens opacification in postmenopausal women.

Novel structural features increase the antioxidant effect of estrogen analogues on low density lipoprotein

Many known estrogens, both natural and synthetic, may act as antioxidants. We designed and synthesized 22 novel estrogen analogues with different ring junctions or substitutions, such as fluorine. We studied the antioxidant capacity in vitro of 35 synthetic estrogen analogues in aqueous lipoprotein solution by monitoring the formation of conjugated dienes. In addition to a free C-3 hydroxyl group, the two most active antioxidants had either a methyl group at C-4 and a six-carbon D-ring, or a fluorine atom at C-2 and an unsaturated B-ring. Extension of the D-ring increased the antioxidant capacity of 6-oxa estrogens. Compounds with a fluorine atom at C-2 were similar or more potent antioxidants compared with the principal endogenous estrogen, 17β-estradiol. In compounds with a substituted C-3 hydroxyl group, the antioxidant capacity could be significantly increased by additional double bonds in the C- or D-rings. In conclusion, we show that the antioxidant capacity of estrogen analogues could be increased by structural changes.

Estrogen alleviates acetic acid-induced gastric or colonic damage via both ERα- and ERβ-mediated and direct antioxidant mechanisms in rats

In order to demonstrate the possible protective effects of estrogen receptor (ER)-α and ERβ receptor subtypes in the pathogenesis of colonic and gastric oxidant damage, experimental ulcer and colitis were induced by acetic acid, and the animals were randomly divided as colitis, ulcer, and their corresponding non-ulcer and non-colitis control groups. Each group of rats was treated intramuscularly with the vehicle, selective ERα agonist propylpyrazole-triol (1 mg/kg), ERβ agonist diarylpropionitrile (1 mg/kg), non-selective ER agonist 17β estradiol (E2; 1 mg/kg), or E2 plus non-selective ER antagonist ICI-182780 (1 mg/kg). The results revealed that induction of ulcer or colitis resulted in systemic inflammation as assessed by increased levels of plasma TNF-α and IL-6 levels. In both tissues, the presence of oxidant damage was verified by histological analysis and elevated myleoperoxidase activity. In the colitis and ulcer groups, both ER agonists and the non-selective E2 reversed the oxidative damage in a similar manner. These findings indicate that estrogen acts via both ERα- and ERβ-mediated and direct antioxidant mechanisms, where both ER subtypes play equal and efficient roles in the anti-inflammatory action of estrogen, in limiting the migration of neutrophils to the inflamed tissue, reducing the release and activation of cytokines and thereby alleviating tissue damage.

Protective effect of 17β-estradiol on serum deprivation-induced apoptosis and oxidative stress in bone marrow-derived mesenchymal stem cells

Stem cell transplantation has indicated great promise for cell therapy in a wide range of diseases, but poor and insufficient viability of cells within damaged tissues has limited its potential therapeutic effects. 17 β-Estradiol (E2) is a steroid hormone that plays an important role in expression of many genes and regulating proliferation, viability, and intracellular redox status in different cell types. In this study, we aimed to assess the effect of E2 on bone marrow-derived mesenchymal stem cells (BM-MSCs). Apoptosis was induced by serum deprivation (SD), and cells were exposed to E2 in the presence or absence of serum for varying periods of time, after which cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Expression of proapoptotic and antiapoptotic proteins after exposure to E2 was examined by Western blotting. The ability of E2 to prevent reactive oxygen species (ROS) production was also measured. The results indicated that E2 significantly enhanced the viability of the cells and protected BM-MSCs against SD-induced overproduction of ROS. It could reduce lipid peroxidation, total antioxidant power, and also Bax/Bcl-2 ratio as well as expression of caspase-3. Taken together, our data support that E2 treatment protects BM-MSCs against SD-induced damage by regulating ROS production and upregulation of antiapoptotic/proapoptotic proteins ratio.

Cardiovascular autonomic dysfunction and oxidative stress induced by fructose overload in an experimental model of hypertension and menopause

Background

Metabolic syndrome is characterized by the association of 3 or more risk factors, including: abdominal obesity associated with an excess of abdominal fat, insulin resistance, type 2 diabetes, dyslipidemia and hypertension. Moreover, the prevalence of hypertension and metabolic dysfunctions sharply increases after the menopause. However, the mechanisms involved in these changes are not well understood. Thus, the aim of this study was to assess the effects of fructose overload on cardiovascular autonomic modulation, inflammation and cardiac oxidative stress in an experimental model of hypertension and menopause.

Methods

Female SHR rats were divided into (n = 8/group): hypertensive (H), hypertensive ovariectomized (HO) and hypertensive ovariectomized undergoing fructose overload (100 g/L in drinking water) (FHO). Arterial pressure (AP) signals were directly recorded. Cardiac autonomic modulation was evaluated by spectral analysis. Oxidative stress was evaluated in cardiac tissue.

Results

AP was higher in the FHO group when compared to the other groups. Fructose overload promoted an increase in body and fat weight, triglyceride concentration and a reduction in insulin sensitivity. IL-10 was reduced in the FHO group when compared to the H group. TNF-α was higher in the FHO when compared to all other groups. Lipoperoxidation was higher and glutathione redox balance was reduced in the FHO group when compared to other groups, an indication of increased oxidative stress. A negative correlation was found between IL-10 and adipose tissue.

Conclusion

Fructose overload promoted an impairment in cardiac autonomic modulation associated with inflammation and oxidative stress in hypertensive rats undergoing ovarian hormone deprivation.

The gender-differentiated antioxidant effects of a lutein-containing supplement in the aqueous humor of patients with senile cataracts

Antioxidant supplements are expected to decrease oxidative damage and prevent ocular diseases. In this study, changes in the anti-oxidative ability and oxidative status in the aqueous humor before and after intake of a lutein-containing supplement were measured. Forty patients who all had identical grades of cataracts in both eyes were included. The aqueous humor was collected as pre-intake samples during cataract surgery. Ocuvite + Lutein(Ⓡ), an antioxidant supplement, was administered orally beginning the day after surgery. Six weeks later, the aqueous humor was collected as a post-intake sample during cataract surgery of the opposite eye. To determine the anti-oxidative ability, the levels of superoxide (O2(*-)) scavenging activity were measured. To determine the oxidative status, the levels of hydrogen peroxide (H2O2) and total amount of hydroperoxides (TH, including H2O2 and peroxides of lipids, proteins, and nucleic acids) were measured. In post-intake samples, the O2(*-) scavenging activities were significantly higher in both genders (p < 0.05). The levels of H2O2 were significantly higher (p < 0.01) while the levels of TH were significantly lower (p < 0.01) only in females. The level of H2O2 was significantly negatively correlated to the TH in the post-intake samples of both genders (r = -0.50 and p < 0.05 for males; r = -0.59 and p < 0.01 for females) while the level of H2O2 was significantly positively correlated to the O2(*-) scavenging activity in both pre- and post-intake aqueous humor in females only (r = 0.66 and p < 0.01 for pre-intake samples, r = 0.71 and p < 0.01 for post-intake samples). After the introduction of the antioxidant supplement, O2(*-) scavenging activity increased while H2O2 levels remained the same in males, suggesting that scavenging rates are proportional. In postmenopausal females, the superoxide scavenging activity also increased, however unlike in males, the H2O2 levels also increased meaning H2O2 was not completely scavenged. H2O2 is a non-free radical and can be excreted from the aqueous humor to prevent further oxidation of lipids, proteins, and nucleic acids, which was confirmed by the low levels of TH in post-intake samples. Antioxidant supplements are suggested to be effective in reducing oxidation in the aqueous humor by different mechanisms in both genders.

Gender differences in the association between serum γ-glutamyltransferase and blood pressure change: a prospective community-based cohort study

We evaluated the gender differences in the relation of baseline serum γ-glutamyltransferase (GGT) levels to blood pressure (BP) change during 4 yr. 4,025 normotensive subjects (1,945 men and 2,080 women) who aged 40-69 yr at baseline participated in the Ansung-Ansan cohort of the Korean Genome Epidemiology Study were included. The associations of GGT with baseline BP or 4-yr change of BP were evaluated. GGT levels were associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) at baseline after adjusting for age, body mass index (BMI), HDL-cholesterol, triglyceride, C-reactive protein (CRP), current smoking status and alcohol intake (SBP, β=1.28, P<0.001; DBP, β=1.41, P<0.001). GGT levels were also associated with 4-yr change in BP after adjusting for age, BMI, HDL-cholesterol, triglyceride, CRP, current smoking status, alcohol intake and SBP (SBP, β=1.08, P=0.001; DBP, β=0.64, P=0.003). This association was statistically significant in men (SBP, β=1.82, P<0.001; DBP, β=1.05, P=0.001), but not in women (SBP, β=0.38, P=0.466; DBP, β=-0.37, P=0.304). Remarkably, this association between GGT and BP was significant in men at 40-49 yr of age. In summary, we found positive associations between GGT levels at baseline and the change of BP. The relation of GGT level and the change of BP was only significant in men, not in women, which warrants further studies to elucidate the biologic mechanisms.

Molecular mechanism of 17α-ethinylestradiol cytotoxicity in isolated rat hepatocytes

17α-Ethinylestradiol (17-EE) is used in formulations of contraceptives and hormone replacement therapy because it is an estradiol derivative. However, it has been associated with an increase in the risk of liver cancers and injury. The carcinogenic properties of 17-EE are similar to that of other estrogens, but the molecular mechanism of liver injury is still unclear. It is important to identify any secondary toxic mechanisms that can be used to prevent or treat the toxicity. The LC50 of 17-EE toward isolated rat hepatocytes was determined to be 150 ± 8 μmol/L. Accelerated cytotoxicity mechanism screening (ACMS) techniques using isolated rat hepatocytes showed that CYP1A inhibitors decreased cytotoxicity, whereas tyrosinase increased toxicity; this suggests that the toxic mechanism involved is the oxidation of 17-EE. A hepatocyte inflammation model also increased 17-EE-induced mitochondrial toxicity, as well as the formation of ROS and H2O2. Cytotoxicity was increased when inhibitors of quinone reduction, catechol-O-methylation, glucuronidation, glutathione conjugation, and sulfation were co-incubated with 17-EE. The hepatocytes could be rescued with antioxidants and quinone trapping agents, thereby suggesting a role for quinoid moiety induced oxidative stress in 17-EE induced cytotoxicity. These mechanisms for 17-EE hepatotoxicity could provide a new perspective for the treating 17-EE-induced liver injury.

Quantitative structure-activity relationships predicting the antioxidant potency of 17β-estradiol-related polycyclic phenols to inhibit lipid peroxidation

The antioxidant potency of 17β-estradiol and related polycyclic phenols has been well established. This property is an important component of the complex events by which these types of agents are capable to protect neurons against the detrimental consequences of oxidative stress. In order to relate their molecular structure and properties with their capacity to inhibit lipid peroxidation, a marker of oxidative stress, quantitative structure-activity relationship (QSAR) studies were conducted. The inhibition of Fe³⁺-induced lipid peroxidation in rat brain homogenate, measured through an assay detecting thiobarbituric acid reactive substances for about seventy compounds were correlated with various molecular descriptors. We found that lipophilicity (modeled by the logarithm of the n-octanol/water partition coefficient, logP) was the property that influenced most profoundly the potency of these compounds to inhibit lipid peroxidation in the biological medium studied. Additionally, the important contribution of the bond dissociation enthalpy of the phenolic O–H group, a shape index, the solvent-accessible surface area and the energy required to remove an electron from the highest occupied molecular orbital were also confirmed. Several QSAR equations were validated as potentially useful exploratory tools for identifying or designing novel phenolic antioxidants incorporating the structural backbone of 17β-estradiol to assist therapy development against oxidative stress-associated neurodegeneration.

Impact of Serum Estradiol on Biomarkers of Oxidative Stress in Polycystic Ovary Syndrome and Ovulatory Women

Background

Estrogens are thought to possess antioxidant properties in vivo, with estradiol being the most biologically active and available. Unlike ovulatory women, those with polycystic ovary syndrome (PCOS) have a relative steady-state serum estradiol concentration across a typical month. To better understand the antioxidant role of serum estradiol in premenopausal women, we evaluated biomarkers of oxidative stress at two time points in both ovulatory and anovulatory cycles (ie, women with PCOS).

Methods

A total of 16 women (7 PCOS, 9 ovulatory) completed this study. Ovulatory women were tested on cycle day 3, and again on cycle day 21. Women with PCOS were tested at a random time and returned to the clinic 14 days later. At each visit, blood was collected for determination of malondialdehyde (MDA), hydrogen peroxide (H2O2) and Trolox Equivalent Antioxidant Capacity (TEAC). Estradiol, progesterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were also measured.

Results

There were no significant differences observed in any oxidative stress biomarker between ovulatory and PCOS women. Estradiol levels were positively correlated with TEAC in women with PCOS (r = 0.57; P = 0.03), but not in ovulatory women. While not statistically significant, negative correlations were noted between estradiol and MDA and estradiol and H2O2 in women with PCOS but not in ovulatory subjects.

Conclusions

Our data indicate that oxidative stress biomarkers do not differ between PCOS and ovulatory women. The changing estrogen level that occurs throughout ovulatory cycles does not appear to impact overall oxidative status when compared to the relative steady-state estradiol levels in PCOS subjects in our study. Furthermore, estradiol may be associated with antioxidant status and biomarkers of oxidative stress in women with PCOS but not in those with regular menstrual cycles.

Influence of ovariectomy on cardiac oxidative stress in a renovascular hypertension model

The aim of this study was to evaluate the potential influence of endogenous ovarian hormones on cardiac oxidative stress in renovascular hypertension. Female Wistar rats (N = 10 per group) were divided among 4 groups: (i) normotensive control; (ii) hypertensive control; (iii) normotensive ovariectomized; and (iv) hypertensive ovariectomized rats. To induce hypertension, 2-kidney 1-clip (2K1C) Goldblatt's method was followed. Blood pressure (BP) was enhanced (25%) in 2K1C and it was not further altered in hypertensive ovariectomized animals. Lipid peroxidation (measured by thiobarbituric acid reactive substances; TBARS) increased in heart homogenates after ovariectomy (253%) and was additionally augmented when associated with hypertension (by 28%). Superoxide dismutase and catalase activities were similar in both hypertensive groups. Hypertension enhanced glutathione peroxidase activity (75%), but the association with ovariectomy prevented this change. Total radical trapping antioxidant potential (TRAP) decreased in hypertensive rats (34%) and was recovered when associated with ovariectomy. However, this adaptation seems not to be sufficient to avoid the increased oxidative damage in ovariectomized hypertensive animals. These results suggest a protective role for physiological ovarian hormones in the cardiac oxidative stress induced by 2K1C hypertension.

Catalase and estradiol inhibit mitochondrial protein S-glutathionylation

Regulation and downstream effects of mitochondrial protein S-glutathionylation in response to oxidative stress are poorly understood. The study aim was to determine whether anti-oxidants such as catalase and estradiol alter mitochondrial protein S-glutathionylation and in turn affect apoptosis following ultraviolet B (UV-B) light irradiation. HeLa cells were transduced with increasing amounts of adenovirus encoding catalase (Ad-Cat) and β-galactosidase (Ad-Lac Z) or pre-incubated with estradiol before induction of apoptosis by UV-B light exposure. Inhibition of mitochondrial protein S-glutathionylation was assessed using autoantibodies specific for the non-S-glutathionylated form of PDC-E2. The percentage of apoptotic cells following UV-B irradiation were not significantly different between mock cells (cells with no virus infection) and Ad-Cat and Ad-Lac Z infected cells at all viral doses (all p > 0.050). Autoantibody staining of non-S-glutathionylated PDC-E2 in apoptotic cells was three times greater in only Ad-Cat infected cells compared to only Ad-Lac Z infected cells (81.3 ± 16.7 vs 26 ± 7.2 %, respectively, p = 0.030). Similarly estradiol treatment (33 and 100 nM) also significantly increased PDC-E2 staining in apoptotic cells compared to non-treated cells (both p < 0.010). The percentage of apoptotic cells was not significantly different with any of the estradiol concentrations (all p > 0.100). The observed procaspase 12 cleavage following UV-B irradiation suggests that a mitochondrial-independent apoptotic pathway was activated. In conclusion, following an apoptotic stimulus, estradiol may inhibit mitochondrial protein S-glutathionylation without inhibiting apoptosis. This effect may play a role in ninefold greater prevalence of autoantibodies against PDC-E2 in women with primary biliary cirrhosis.

Effects of antioxidant supplementation on mRNA expression of glucose-6-phosphate dehydrogenase, β-actin and 18S rRNA in the anterior capsule of the lens in cataract patients

This was a preliminary study of the effects of antioxidant supplementation on the peroxidation status of the lens by investigating mRNA expression of anti-oxidative enzymes in the lens. The mRNA expression levels of glucose-6-phosphate dehydrogenase (G6PDH), β-actin (β-ACT) and 18S rRNA (18S) were measured in this study because they are common reference genes for measuring mRNA levels by means of a real-time reverse transcription polymerase chain reaction (RT-PCR) in various tissues. Thirteen patients with binocular cataracts of the same grade were included in the study after giving informed consent. A piece of the anterior capsule, along with a sample of lenticular epithelial cells (LECs), was collected as a pre-intake sample during cataract surgery. Ocuvite + Lutein(®), an antioxidant supplement, was administered orally beginning the day after surgery. Six weeks later, a piece of the anterior capsule along with a sample of LECs, was collected as a post-intake sample during cataract surgery of the opposite eye. RNA was purified from the homogenized samples, and cDNA was reverse transcribed to measure mRNA levels. The expression levels of G6PDH, 18S and β-ACT were measured using RT-PCR. The expression levels of G6PDH and 18S were significantly higher in the post-intake samples than they were in the pre-intake samples. Significant positive correlations between the expression levels of G6PDH and 18S were observed in both the pre- and post-intake samples. Following gender-specific analyses, the expression levels of G6PDH and 18S in the post-intake samples were found to be significantly higher among the female patients. A significant positive correlation between the expression levels of G6PDH and 18S was observed in the post-intake samples from the male patients. There were no significant changes in the gene expression levels of β-ACT after supplementation among male or female patients. β-ACT has been verified for use as a reference gene for measuring the effects of antioxidant supplementation in the lens by RT-PCR. Antioxidant supplementation was noted to increase G6PDH in the pentose phosphate cycle and 18S rRNA in the ribosome.

Energy expenditure and plasma F2-isoprostanes across the menstrual cycle

INTRODUCTION

Habitual energy expenditure seems to favorably alter oxidant/antioxidant balance. Sparse evidence suggests that hormones that fluctuate during the menstrual cycle, particularly estrogens, may influence concentrations of oxidative biomarkers and their relation to energy expenditure.

METHODS

We investigated the relation between energy expenditure and plasma free F2-isoprostane concentrations in 259 healthy, regularly menstruating 18- to 44-yr-old participants of the BioCycle Study. Habitual energy expenditure was measured using a baseline International Physical Activity Questionnaire and categorized as low, moderate, or high. Women were followed for one or two subsequent menstrual cycles. Past-week and past-day physical activity were measured during follow-up using questionnaires and diaries, respectively. F2-isoprostane concentrations were measured in blood samples collected at both menses (approximate cycle day 2; low serum estradiol concentration) and the late follicular phase (approximate cycle day 12; peak estradiol concentration). Generalized estimating equations were used to model the energy expenditure/isoprostane association, adjusting for confounders.

RESULTS

Habitual energy expenditure was positively associated with F2-isoprostane concentration (adjusted difference in median F2-isoprostane, high versus low energy expenditure: 17.4%; 95% confidence interval (CI)=3.3%-31.4%). This association was not modified by cycle phase (interaction, P=0.61) or differences in peak estradiol concentration across women (interaction, P=0.20). Past-week and past-day physical activity measures were not associated with F2-isoprostane concentration (category trend, P=0.50 and P=0.18, respectively).

CONCLUSIONS

These results suggest that higher habitual energy expenditure may be associated with higher concentration of F2-isoprostanes in healthy, reproductive-aged women. Estradiol concentration changes during the menstrual cycle do not seem to influence this relationship.

Lower postprandial oxidative stress in women compared with men

BACKGROUND

Previous studies indicate that oxidative stress is increased following intake of a high-fat meal, mediated in large part by the triglyceride (TG) response to feeding as well as fasting oxidative stress values. It has been suggested that women may process TG more efficiently after high-fat meals, based on the antilipidemic properties of estrogen. It has also been reported that women present with lower fasting oxidative stress values than do men. It is possible that women experience attenuated postprandial oxidative stress compared with men.

OBJECTIVE

The purpose of this study was to compare the postprandial TG and oxidative stress response after a lipid meal in healthy men and women.

METHODS

This study was conducted at The University of Memphis in Memphis, Tennessee, from October to December 2008. Blood samples were collected before (in a 10-hour fasted state), and at 1, 2, 4, and 6 hours after ingestion of a lipid load (heavy whipping cream at 1 g · kg(-1)). Blood samples were analyzed for TG, malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), and nitrate/nitrite (NOx). The AUC was calculated for each variable and results were compared using a t test. Effect-size calculations were performed using Cohen's d.

RESULTS

Samples from 10 men and 10 women, aged 18 to 47 years (17 subjects aged <37 years), were compared. AUC data were not significantly different for TG (mean [SEM] 330 [48] vs 354 [34] mg · dL(-1) · 6h(-1) for men and women, respectively; effect size = 0.09) or NOx (165 [25] vs 152 [17] μmol · L(-1) · 6h(-1) for men and women; effect size = 0.09). However, significant differences were noted for MDA (10.7 [1.3] vs 6.1 [0.5] μmol · L(-1) · 6h(-1) for men and women, respectively; P = 0.002; effect size = 0.61) and H(2)O(2) (154 [23] vs 86 [8] μmol · L(-1) · 6h(-1) for men and women; P = 0.013; effect size = 0.53).

CONCLUSIONS

These data indicate that women experience lower oxidative stress than do men, with regard to MDA and H(2)O(2), after ingestion of a lipid load in the form of heavy whipping cream. Considering the strong association between oxidative stress and cardiovascular disease, lower postprandial oxidative stress may be one mechanism associated with decreased risk of cardiovascular disease in women compared with men. Further research is needed to confirm this hypothesis.

The assessment of non-feminizing estrogens for use in neuroprotection

Menopause is associated with a precipitous decline in circulating estrogens and a resulting loss of the neuroprotective actions of this steroid hormone. In view of the results of the Women's Health Initiative and the preceding knowledge that orally administered estrogens has a variety of adverse side effects, likely through actions on peripheral estrogen receptor alpha (ERα), we initiated a program of research to synthesis and assess a group of non-feminizing estrogens that lack ability to interact with ERs but retain much of the neuroprotective action of feminizing estrogens. This program of research is aimed at the identification of compounds which do not stimulate ERs but are potentially neuroprotective in vitro and in animal models of neuronal cell death. We discovered that the most effective non-feminizing estrogens were those with large bulky groups in the 2 and/or 4 carbon of the phenolic A ring of the steroid. These compounds were 8- to 114-fold more potent than 17 β-estradiol (βE2), but lacked ER binding capacity in vitro and feminizing effects in vivo. The success of this program of research suggests that strategies to optimize non-feminizing estrogens for use in postmenopausal women can be successful.

The effects of polymicrobial sepsis with diabetes mellitus on kidney tissues in ovariectomized rats

OBJECTIVES

Sepsis model was used to understand the role of sustained hyperglycemia and ovariectomy, either separately or concomitantly, on the response of the activity of the nuclear factor kappa B (NF-kappaB) and the oxidative response in kidney.

SUBJECTS

Polymicrobial sepsis was induced by cecal ligation and puncture (CLP). Diabetes was induced in female rats using administration of alloxan. The rats were divided into five groups: sham control (group 1), ovariectomy (group 2), ovariectomy + sepsis (group 3), ovariectomy + diabetes (group 4), and ovariectomy + diabetic + sepsis (group 5).

RESULTS

In kidney tissues, the levels of lipid peroxidation (LPO) and glutathione (GSH) and the activity of catalase (CAT) were higher for groups 3, 4, 5 than the control groups. Superoxide dismutase (SOD) activity was lower for groups 3, 4, 5 than the control groups. We determined that CLP produced injury evident in the kidneys of rats when compared to the control group, whereas the severity of the injury was higher in the diabetes + ovariectomy + CLP group when compared to the CLP group. In immunohistochemical staining, we determined that CLP operation increased NF-kappaB activation. In the ovariectomized, septic, and diabetic group, NF-kappaB activation was significantly higher than other groups.

CONCLUSIONS

Hyperglycemia and ovariectomy severely increased NF-kappaB activation and oxidant levels with the stages of our sepsis model. Ovariectomy resulted in general changes in metabolism, which are seen in the kidney with diabetes under sepsis conditions.

Influence of endogenous reproductive hormones on F2-isoprostane levels in premenopausal women: the BioCycle Study

Endogenous reproductive hormones and oxidative stress have been independently linked to risk of chronic disease but mostly in postmenopausal women. The interplay between endogenous reproductive hormones and oxidative stress among premenopausal women, however, has yet to be clearly elucidated. The objective of this study was to investigate the association between endogenous reproductive hormones and F(2)-isoprostanes in the BioCycle Study. Women aged 18-44 years from western New York State were followed prospectively for up to 2 menstrual cycles (n = 259) during 2005-2007. Estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, sex hormone-binding globulin, F(2)-isoprostanes, and thiobarbituric acid-reactive substances were measured up to 8 times per cycle at clinic visits timed by using fertility monitors. F(2)-Isoprostane levels had an independent positive association with estradiol (beta = 0.02, 95% confidence interval: 0.01, 0.03) and inverse associations with sex hormone-binding globulin and follicle-stimulating hormone (beta = -0.04, 95% confidence interval: -0.07, -0.003; beta = -0.02, 95% confidence interval: -0.03, -0.002, respectively) after adjustment for age, race, age at menarche, gamma-tocopherol, beta-carotene, total cholesterol, and homocysteine by inverse probability weighting. Thiobarbituric acid-reactive substances, a less specific marker of oxidative stress, had similar associations. If F(2)-isoprostanes are specific markers of oxidative stress, these results call into question the commonly held hypothesis that endogenous estradiol reduces oxidative stress.

Impact of serum estradiol on postprandial lipemia, oxidative stress, and inflammation across a single menstrual cycle

BACKGROUND

An abrupt rise in circulating lipids, oxidative stress, and inflammatory biomarkers is a common finding after ingestion of a high-fat meal. Estradiol, typically provided via hormone replacement therapy to postmenopausal women, has been reported to possess lipidemic, antioxidant, and antiinflammatory properties, all of which may minimize postprandial oxidative stress.

OBJECTIVE

The purpose of this study was to compare the postprandial triglyceride (TG), oxidative stress, and inflammatory responses after a lipid meal in menstruating women during the early follicular (days 1-3) and preovulatory (day 14) phases of the menstrual cycle.

METHODS

Healthy normolipidemic women (fasting blood TG, <200 mg/dL) with regular menstrual cycles reported to the Cardiorespiratory/Metabolic Laboratory at the University of Memphis, Memphis, Tennessee (October-December 2008) and consumed an identical lipid meal (heavy whipping cream and water) on 2 separate days during the menstrual cycle. Blood samples were collected premeal and 1, 2, 4, and 6 hours postmeal, then assayed for TG, malondialdehyde (MDA), hydrogen peroxide, Trolox equivalent antioxidant capacity (TEAL), nitrate/nitrite, and C-reactive protein (CRP). The AUC was calculated for each variable, and a 2 (menstrual cycle phase) x 5 (time) ANOVA with Tukey post hoc testing was also conducted. Estradiol concentration was measured in premeal samples for verification of cycle phase.

RESULTS

Ten women (mean [SD] age, 29 [11] years; 8 white, 2 black; body mass index, 22 [3] kg/m(2)) participated in the study. Despite a higher serum estradiol concentration on day 14 (113 [56] pg/mL) compared with the early follicular phase (61 [34] pg/mL), the TG, oxidative stress, and inflammatory AUC responses to feeding were not significantly different. TG (P = 0.03), MDA (P = 0.02), and hydrogen peroxide (P < 0.001) were significantly increased in response to feeding (time effect), whereas nitrate/nitrite was decreased (P = 0.01). TEAC and CRP were not significantly affected.

CONCLUSIONS

These data indicate that estradiol, at the concentrations noted in the present study, had no significant effect on postprandial TG or biomarkers of oxidative stress or inflammation in a sample of young, healthy women. It is possible that a greater divergence in circulating estradiol may be needed for significant differences to be detected, as may be the case with chronic hormone replacement therapy in postmenopausal women.

Influence of ripeness and drying process on the polyphenols and tocopherols of Pistacia vera L

This paper highlights, for the first time, the changes in the phenolics fraction (anthocyanins, flavonoids and stilbenes) and tocopherols of unpeeled Pistacia vera L. var. bianca with ripening, and the effect of the sun-drying process. The total polyphenol levels in pistachios, measured as mg of Gallic Acid Equivalent (GAE), were: 201 +/- 10.1, 349 +/- 18.3 and 184.7 +/- 6.2 mg GAE/100 g DM in unripe, ripe and dried ripe samples, respectively. Most phenolics in ripe pistachios were found to be anthocyanins. They increased with ripening, while the sun drying process caused a susbtantial loss. Flavonoids found in all pistachio samples were daidzein, genistein, daidzin, quercetin, eriodictyol, luteolin, genistin and naringenin, which decreased both with ripening and drying. Before the drying process both unripe and ripe pistachios showed a higher content of trans-resveratrol than dried ripe samples. gamma-Tocopherol was the major vitamin E isomer found in pistachios. The total content (of alpha- and gamma-tocopherols) decreased, both during ripening and during the drying process. These results suggested that unpeeled pistachios can be considered an important source of phenolics, particularly of anthocyanins. Moreover, in order to preserve these healthy characteristics, new and more efficient drying processes should be adopted.

Oestradiol protects against the harmful effects of fluoride more by increasing thiol group levels than scavenging hydroxyl radicals

The aim of the study was to investigate the role of oestrogens in free radical detoxication upon exposure to fluoride. Interactions between xenobiotics and oestrogens need to be investigated, especially as many chemicals interact with the oestrogen receptor. It is still unknown whether free radical-generating xenobiotics can influence the antioxidative ability of oestradiol (E(2)). In an in vitro examination of human placental mitochondria, thiobarbituric active reagent species (TBARS), hydroxyl radical ((*)OH) generation and protein thiol (-SH) groups were detected. 17beta-E(2) was examined in physiological (0.15-0.73 nM) and experimental (1-10 microM) concentrations and sodium fluoride (NaF) in concentrations of 6-24 microM. E(2) in all the concentrations significantly decreased lipid peroxidation measured as the TBARS level, in contrast to NaF, which increased lipid peroxidation. Lipid peroxidation induced by NaF was decreased by E(2). The influence of E(2) on (*)OH generation was not very significant and depended on the E(2 )concentration. The main mechanism of E(2) protection in NaF exposure appeared to be connected with the influence of E(2 )on thiol group levels, not (*)OH scavenging ability. The E(2) in concentrations 0.44-0.73 nM and 1-10 microM significantly increased the levels of -SH groups, in contrast to NaF, which significantly decreased them. E(2) at every concentration reversed the harmful effects of NaF on -SH group levels. No unfavourable interactions in the influence of E(2) and NaF on TBARS production, (*)OH generation, or -SH group levels were observed. The results suggest that postmenopausal women could be more sensitive to NaF-initiated oxidative stress.

Correlation of increased oxidative stress to body weight in disease-free post menopausal women

OBJECTIVES

Oxidative stress increases postmenopausally, an effect attributed to aging. Increase in body weight generally accompanies menopause. Obesity per se also seems to increase oxidative stress. The question is whether postmenopausal increase in oxidative stress is related to body weight, or is only a function of age.

DESIGN AND METHODS

Age, body weight, and superoxide dismutase (SOD), catalase (CAT) and malonyldialdehyde (MDA) in erythrocytes of a cross-section of 90 disease-free women aged 25-65 years, divided into three groups of n=30 each of normally menstruating Controls (C), perimenopausal (periM) and postmenopausal women (postM) were recorded.

RESULTS

PostM had the highest oxidative stress and body weight. SOD, CAT and MDA correlated significantly with body weight (-0.74, 0.64 and 0.69 respectively). The odds of having a lower SOD (OR9.5, 95% CI:2.9-30.8) and higher CAT (OR6.2, 95% CI:1.6-23.0) and MDA (OR6.8, 95% CI:2.7-16.8) for weight >60 kg was highly significant.

CONCLUSIONS

Oxidative stress is enhanced as body weight increases.

Balance of beneficial and deleterious health effects of quinones: a case study of the chemical properties of genistein and estrone quinones

Substances containing a phenolic moiety are often metabolized to quinones whose high reactivity makes them difficult to study. Some of these precursors have clear health benefits, and some quinones themselves are used in cancer therapy, whereas others are deleterious. For example, dietary intake of phytoestrogen, genistein (Gen), seems to play a preventive role in breast cancer (BC) whereas prolonged exposure to chemically similar mammalian estrogens is clearly associated with elevated incidence of BC. Although both can be metabolized to reactive quinones, the catechol estrogen quinones (CEQs) modify DNA by redox cycling and/or depurination via a Michael addition. Here, we report an investigation of the chemical reactivity of Gen and estrone quinones to determine the chemical differences of these two biologically important molecules. The catechol genistein quinone (CGenQ), has a half-life of 4 +/- 1 s under physiological condition, as determined by glutathione trapping. It disappears by reacting with H2O to give a dihydrate, CGenQ x (H2O)2, whose structure was proved by NMR. Under reductive conditions, CGenQ x (H2O)2 is readily reduced to reform the catechol genistein (CGen). This reversible oxidation of CGen to CGenQ and the prompt moderation of its reactivity by hydration to CGenQ x (H2O)2 effectively hinders any redox cycling or depurination reaction of CGenQ with DNA. Catechol estrogen quinones, on the other hand, are sufficiently long-lived that they can damage DNA via a Michael addition or by redox cycling. Although the reactivity of CEQ in a nonaqueous solvent is similar to that of CGenQ, its reactivity in aqueous media with the free Ade base is more than 600 times that of CGenQ. These results suggest that rapid hydration of a quinone can moderate its reactivity toward biomolecules, allowing them to express, for example, estrogen-like properties without exhibiting the deleterious properties of redox cycling or directly damaging DNA via depurination reactions.

Estrogen deficiency-induced alterations of vascular MMP-2, MT1-MMP, and TIMP-2 in ovariectomized rats

BACKGROUND

Matrix metalloproteinases (MMPs) activity may modulate hypertension-related accumulation of extracellular matrix (ECM) in arteries. We tested whether estrogen deficiency induces alterations of vascular collagen, MMP-2, membrane-type 1-MMP (MT1-MMP), or tissue inhibitor of metalloproteinases-2 (TIMP-2) expression in ovariectomized rats, which may be associated with postmenopausal hypertension.

METHODS

Estrogen deficiency was induced by ovariectomy (Ovx) in female rats. Time-course changes of aortic MMPs protein expression were evaluated. Treatment with tempol or aminoguanidine was used to examine the role of oxidative stress and nitric oxide (NO) on these changes.

RESULTS

The level of the active-form MMP-2 was markedly reduced during 1-4 weeks after Ovx, with a significant increase in collagen accumulation and increased MT1-MMP expression. Although active-form MMP-2 and collagen progressively returned to normal levels, the markedly increased collagen deposition appeared again at 8 weeks and persisted until 12 weeks, followed by induction of MMP-2 and MT1-MMP at 12 weeks. The TIMP-2 level reduced for 2 weeks after Ovx, but soon returned to normal. Treatment with 17beta-estradiol (E(2)), tempol, or aminoguanidine for 6 weeks prevented Ovx-induced blood pressure elevation and apparently reversed the MMPs changes.

CONCLUSIONS

In an initial period, E(2) deficiency induces a reduction of active-form MMP-2 leading to collagen accumulation, and induction of MT1-MMP, which may be a compensatory response to degrade collagen. At a latter stage, the concurrent elevation of active-form MMP-2 and MT1-MMP expression may be adaptive responses to regulate ECM composition in the vascular wall. Oxidative stress and NO contribute to activity modulation of vascular MMPs in Ovx rats.