Effects of oestradiol and oestroprogestin on erythrocyte antioxidative enzyme system activity in postmenopausal women

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.

Ameliorative Effect of Tocotrienols on Perimenopausal-Associated Osteoporosis-A Review

Osteoporosis, or bone loss, is a disease that affects many women globally. As life expectancy increases, the risk of osteoporosis in women also increases, too, and this will create a burden on the healthcare and economic sectors of a country. Osteoporosis was once thought to be a disease that would occur only after menopause. However, many studies have shown that osteoporosis may develop even in the perimenopausal stage. Due to the erratic levels of estrogen and progesterone during the perimenopausal stage, studies suggest that women are exposed to the risk of developing osteoporosis even at this stage. The erratic hormonal changes result in the production of proinflammatory mediators and cause oxidative stress, which leads to the progressive loss of bone-building activities. Tocotrienols, members of vitamin E, have many health-promoting properties. Due to their powerful anti-oxidative and anti-inflammatory properties, tocotrienols have shown positive anti-osteoporotic properties in post-menopausal studies. Hence, we propose here that tocotrienols could also possibly alleviate perimenopausal osteoporosis by discussing in this review the connection between inflammatory mediators produced during perimenopause and the risk of osteoporosis. Tocotrienols could potentially be an anti-osteoporotic agent, but due to their low bioavailability, they have not been as effective as they could be. Several approaches have been evaluated to overcome this issue, as presented in this review. As the anti-osteoporotic effects of tocotrienols were mostly studied in post-menopausal models, we hope that this review could pave the way for more research to be done to evaluate their effect on peri-menopausal models so as to reduce the risk of osteoporosis from an earlier stage.

Are Oxidative Stress and Inflammation Mediators of Bone Loss Due to Estrogen Deficiency? A Review of Current Evidence

Osteoporosis is one of the major health issues associated with menopause-related estrogen deficiency. Various reports suggest that the hormonal changes related to menopausal transition may lead to the derangement of redox homeostasis and ultimately oxidative stress. Estrogen deficiency and oxidative stress may enhance the expression of genes involved in inflammation. All these factors may contribute, in synergy, to the development of postmenopausal osteoporosis. Previous studies suggest that estrogen may act as an antioxidant to protect the bone against oxidative stress, and as an antiinflammatory agent in suppressing pro-inflammatory and pro-osteoclastic cytokines. Thus, the focus of the current review is to examine the relationship between estrogen deficiency, oxidative stress and inflammation, and the impacts of these phenomena on skeletal health in postmenopausal women.

Effect of lycopene on titanium implant osseointegration in ovariectomized rats

Background

Lycopene prevents bone loss in osteopenic models. However, the role of lycopene in the success rate of dental implants under osteopenic conditions remains unknown. The aim of this study was to evaluate whether lycopene prevents delayed implant osseointegration in an ovariectomized (OVX) rat model.

Methods

Thirty female Sprague-Dawley rats were randomly divided into the following groups: OVX with vehicle (OVX group), OVX with lycopene (OVX + lycopene group) and sham-operated with vehicle (sham group). Twelve weeks after ovariectomy or sham operation, titanium implants were placed into the distal metaphysis of the bilateral femurs of each rat. These rats were subsequently gavaged with lycopene (50 mg/kg/day) or vehicle. After 12 weeks of gavage, all rats were sacrificed, and specimens were harvested. Sample osseointegration was evaluated by biomechanical testing, 3D micro-computed tomography (micro-CT) analysis and histomorphometric analysis.

Results

Compared with the OVX group, the OVX + lycopene group showed a 69.3% increase in the maximum push-out force (p < 0.01). Micro-CT data for the femurs in the OVX + lycopene group showed significantly higher bone volume, trabecular thickness and less trabecular space than did those in the OVX group. The bone area (BA) around the implant and bone contact (BC) with the implant were increased by 72.3% (p < 0.01) and 51.4% (p < 0.01) in the OVX + lycopene group, respectively, compared with those in the OVX group. There was no significant difference in the mechanical test, micro-CT scanning and histomorphometric data between the OVX + lycopene and sham groups (p > 0.05).

Conclusions

Lycopene improved implant osseointegration, fixation and bone formation under osteopenic conditions, suggesting that lycopene is a promising therapeutic agent to prevent delayed implant osseointegration and bone loss under osteopenic conditions.

Perturbed adipose tissue hydrogen peroxide metabolism in centrally obese men: Association with insulin resistance

Objective

Although adipose tissue hydrogen peroxide (H₂O₂) and its metabolizing enzymes have been linked to obesity and insulin resistance in animal studies, this relation remains to be evaluated in humans.

Methods

Non-diabetic men (N = 43, median age, 49 (37, 54 y)) undergoing abdominal surgeries were studied. Participants were classified by body mass index (BMI) into normal-weight (N = 19), or overweight/obese (Ow/Ob; BMI ≥25; N = 24). Centrally obese men were identified by waist-height ratio ≥0.5. H₂O₂ and activities of superoxide dismutase, catalase and glutathione peroxidase enzymes were assayed in subcutaneous fat samples, and visceral fat (available from N = 33), and their associations with anthropometric parameters, fasting serum lipids, and the homeostasis model of insulin resistance (HOMA-IR) were tested using correlations and multivariate linear regression.

Results

H₂O₂ concentrations and catalase activity were increased in visceral fat from Ow/Ob men, compared to normal-weight subjects (+32%, P = 0.038 and +51%, P = 0.043 respectively). Centrally obese subjects had >2-fold higher superoxide dismutase activity (P = 0.005), 46% higher H₂O₂ (P = 0.028), and 89% higher catalase activity (P = 0.009) in visceral fat, compared to lean subjects. Central obesity did not alter these markers in subcutaneous fat, apart from a 50% increase in catalase, and did not affect glutathione peroxidase in either fat depot. H₂O₂ in visceral fat positively correlated with insulin resistance (r = 0.40, P = 0.032). Catalase activity in visceral fat was an independent determinant of HOMA-IR, explaining ~18% of the variance (ß = 0.42, P = 0.016), after adjustment for age and BMI.

Conclusion

These findings suggest that adipose tissue catalase shows compensatory up-regulation in response to obesity-induced H₂O₂ accumulation, and that perturbed H₂O₂ metabolism in visceral fat is linked to insulin resistance in obese humans.

Oxidant/antioxidant status, paraoxonase activity, and lipid profile in plasma of ovariectomized rats under the influence of estrogen, estrogen combined with progesterone, and genistein

INTRODUCTION

The aim of this study was to investigate whether estradiol (E2), E2 combined with progesterone (Prog) (E2/Prog), and genistein (Gen) treatment had antioxidative and anti-hyperlipidemic effects in the plasma of ovariectomized (OVX) rats.

MATERIALS AND METHODS

Adult female Sprague-Dawley rats were divided into five groups. Rats in all groups, except for those in a sham group, underwent bilateral ovariectomy under general anesthesia. The groups were as follows: sham group; control OVX group; group treated with estrogen (0.014 mg/kg 17-β E2); group treated with a combination of E2 and Prog (0.014 mg/kg 17-β E2 plus 0.028 mg/kg drospirenone), and group treated with Gen (10 mg/kg/day). Plasma of rats of each treatment group was analyzed to determine the total antioxidant status, total oxidant status, paraoxonase activity, lipid profile, high-density lipoprotein (HDL-chol), low-density lipoprotein (LDL-chol), total cholesterol (Total-C), triacylglycerols, lipoprotein (a), and oxidative stress index.

RESULTS

Plasma Total-C levels and body weight increased in all the OVX groups compared with the sham group (P<0.005). The group treated with E2 had significantly elevated total oxidant status, oxidative stress index, LDL-chol, and Total-C compared with the control group (P<0.005). Gen treatment might lead to lower LDL-chol and Total-C levels compared with E2 treatment.

CONCLUSIONS

Gen treatment might be preferred to E2 treatment for treatment of menopausal symptoms in patients at risk for cardiovascular diseases. However, considering the small sample size of this study, larger studies are needed in this area.

The protective effect of lycopene intake on bone loss in ovariectomized rats

Antioxidant lycopene supplementation has been shown to decrease oxidative stress and have beneficial effects on bone health. However, it remains unclear whether lycopene exerts its beneficial effect on bone metabolism through mitigation of oxidative stress in vivo. The aim of this study was to investigate whether lycopene intake protects against bone loss by reducing oxidative stress in ovariectomized rats. Female Sprague-Dawley 6-week-old rats were ovariectomized and randomly divided into four groups according to the lycopene content of their diet: 0, 50, 100, and 200 ppm. The tibial bone mineral density (BMD) in the 50, 100, and 200 ppm groups was significantly higher than that in the 0 ppm group. Serum and urinary bone resorption marker levels were significantly lower in the 50, 100, and 200 ppm groups than in the 0 ppm group. There was no significant difference in systemic oxidative stress markers among all groups. However, systemic oxidative stress levels were inversely correlated with the tibial BMD. Our findings suggest that lycopene intake significantly inhibits bone loss by suppressing bone resorption in ovariectomized rats. Further studies are necessary to clarify the effect of lycopene on oxidative stress in local tissues such as bone tissue.

Effects of estrogen on glutathione and catalase levels in human erythrocyte during menstrual cycle

The present study evaluated the effects of physiological serum estrogen during the menstrual cycle on glutathione (GSH) and catalase activities. The sample included 43 healthy females between the ages of 22 and 51 years. The subjects were divided into two groups according to the stage of the menstrual cycle. Group A consisted of 16 samples extracted between days 10 and 20 from the first day of menstruation when estrogen levels were considered to be at their highest. Group B consisted of 27 samples extracted during other times of the estimated 30 days of menstruation. Data showed that the estrogen level in group A (184±106 pg/ml) was higher than that in group B (105±56 pg/ml) (P<0.01). The GSH and catalase levels in group A (4.4±2.3 µg/mg and 210±72 IU/mg, respectively) were also significantly higher compared to the levels in group B (3.2±1.8 µg/mg and 168±62 IU/mg, respectively) (P <0.05). Spearman's rank correlation showed that the expression of catalase in red blood cells significantly correlated with serum estrogen level but not with GSH. However, the changes in estrogen plasma levels, erythrocyte GSH level and catalase activity suggested that the consumption of GSH and catalase in erythrocyte during the menstrual cycle may be associated with the level of estrogen present in the bloodstream.

Protective Effects of Tualang Honey against Oxidative Stress and Anxiety-Like Behaviour in Stressed Ovariectomized Rats

The present study aims to evaluate the antioxidant and anxiolytic-like effect of Tualang honey in stressed ovariectomized (OVX) rats. The animals were divided into; (i) nonstressed sham-operated control rats, (ii) sham-operated control rats exposed to stress, (iii) nonstressed OVX rats, (iv) OVX rats exposed to stress, (v) OVX rats exposed to stress and treated with 17 β-oestradiol (E2) (20 μg daily, sc), and (vi) OVX rats exposed to stress and treated with Tualang honey (0.2 g/kg body weight, orally). The open field test was used to evaluate the anxiety-like behaviour and ELISA kits were used to measure oxidant/antioxidant status of the brain homogenates. The result showed that anxiety-like behavior was significantly increased in stressed OVX compared to other groups, and administering either E2 or Tualang honey significantly decreased anxiety-like behaviour in stressed OVX rats. The levels of malondialdehyde (MDA) and protein carbonyl (PCO) were significantly decreased while the levels/activities of superoxide dismutase (SOD), glutathione S-transferases (GST), glutathione peroxidase (GPx), and glutathione reductase (GR) were significantly increased in the brain homogenates of treated stressed OVX groups compared to untreated stressed OVX. In conclusion, Tualang honey has protective effects against brain oxidative stress and may be useful alternative anxiolytic agent especially for postmenopausal women.

The role of oxidative stress in menopause

This review will discuss the concept of reproductive aging, which includes the definition of menopause, its symptoms, and predisposing conditions. It will elaborate upon the contributory factors implicated in the pathogenesis of menopause, focusing most prominently on oxidative stress. Specifically, this paper will explain how oxidative stress, in the form of free radicals and antioxidant deficiencies, has been directly linked to the decline of estrogen during reproductive aging. Additionally, this paper will elaborate upon the treatment options aimed at mitigating the menopausal symptoms and hormonal deficiencies that can lead to various disease processes. Treatment options such as hormonal therapy, antioxidant supplementation, and lifestyle modification have been explored for their effectiveness in treating and preventing the symptoms and sequelae of menopause. The majority of information in this review was obtained through PubMed and the National Library of Medicine. While most references in this paper are original research articles, a limited number of references are comprehensive reviews on the topic.

Erythrocyte antioxidant protection of rose hips (Rosa spp.)

Rose hips are popular in health promoting products as the fruits contain high content of bioactive compounds. The aim of this study was to investigate whether health benefits are attributable to ascorbic acid, phenols, or other rose-hip-derived compounds. Freeze-dried powder of rose hips was preextracted with metaphosphoric acid and the sample was then sequentially eluted on a C₁₈ column. The degree of amelioration of oxidative damage was determined in an erythrocyte in vitro bioassay by comparing the effects of a reducing agent on erythrocytes alone or on erythrocytes pretreated with berry extracts. The maximum protection against oxidative stress, 59.4 ± 4.0% (mean ± standard deviation), was achieved when incubating the cells with the first eluted meta-phosphoric extract. Removal of ascorbic acid from this extract increased the protection against oxidative stress to 67.9 ± 1.9%. The protection from the 20% and 100% methanol extracts was 20.8 ± 8.2% and 5.0 ± 3.2%, respectively. Antioxidant uptake was confirmed by measurement of catechin by HPLC-ESI-MS in the 20% methanol extract. The fact that all sequentially eluted extracts studied contributed to protective effects on the erythrocytes indicates that rose hips contain a promising level of clinically relevant antioxidant protection.

Estrogen status alters tissue distribution and metabolism of selenium in female rats

A reported association between estrogen and selenium status may be important in the regulation of selenium metabolism. In this study, the effect of estrogen status on the metabolism of orally administered (75)Se-selenite and tissue selenium status was investigated. Female Sprague-Dawley rats were bilaterally ovariectomized at 7 weeks of age and implanted with either a placebo pellet (OVX) or pellet containing estradiol (OVX+E2), or were sham operated (Sham). At 12 weeks of age, 60 µCi of (75)Se as selenite was orally administered to OVX and OVX+E2 rats. Blood and organs were collected 1, 3, 6 and 24 h after dosing. Estrogen status was associated with time-dependent differences in distribution of (75)Se in plasma, red blood cell (RBC), liver, heart, kidney, spleen, brain and thymus and incorporation of (75)Se into plasma selenoprotein P (Sepp1) and glutathione peroxidase (GPx). Estrogen treatment also significantly increased selenium concentration and GPx activity in plasma, liver and brain, selenium concentration in RBC and hepatic Sepp1 and GPx1 messenger RNA. These results suggest that estrogen status affects tissue distribution of selenium by modulating Sepp1, as this protein plays a central role in selenium transport.

The effect of gonadectomy and estradiol on sensitivity to oxidative stress

The sexual dimorphism of life span and caloric restriction effects in numerous species suggest that estradiol (E2) is protective against oxidative damage. The only direct test of E2's protective effect in mice against in vivo oxidative stress to date may have been confounded by E2's direct chemical action as an antioxidant because it was administered at very high dosages. Therefore, we have identified a low yet physiologically effective dose of E2. We then administered this dose using subcutaneous time-release pellets to ovariectomized mice. Two weeks after E2 pellet implantation, sham-operated, ovariectomized, and ovariectomized E2-supplemented female mice were injected with a lethal dose of paraquat and their survival was followed. It was observed that ovariectomy exacerbates paraquat-induced mortality and is rescued by E2 supplementation. An equivalent experiment was performed on sham-operated, orchidectomized, and E2-supplemented orchidectomized male mice. The survival of male mice was improved by orchidectomy, and E2 gave no further benefit. We interpret the results to mean that E2 is protective against oxidative stress through its regulatory role and that testosterone diminishes protection against oxidative stress.