Expression of enzymes involved in synthesis and metabolism of estradiol in human breast as studied by immunocytochemistry and in situ hybridization

Antioxidants (selenium and garlic) alleviated the adverse effects of tramadol on the reproductive system and oxidative stress markers in male rabbits

Tramadol has been used by millions of patients as an analgesic drug to relief the severe pain caused by cancers and other diseases. The current study aimed to investigate the protective effects of antioxidants (garlic and selenium) against the toxic effects of tramadol on semen characteristics, steroid hormones, the protein expressions of different cytochrome P450 isozymes [CYP 21A2, CYP 19, and 11A1], and on antioxidant enzyme activities in testes of rabbits. Western immunoblotting, spectrophotometric, and histological methods were used in this study. Tramadol (1.5 mg/kg body weight) was administered orally to male rabbits for up to three months (three times/week), and after pretreatment of rabbits with garlic (800 mg/kg) and/or selenium (1 mg/kg body weight) by 2 h. The present study showed that motilities, semen volumes, morphologies, sperm counts, testosterone, and estrogen levels were significantly decreased after 4, 8, and 12 weeks of tramadol treatment. In addition, the protein expressions of CYP 21A2, CYP 19, and 11A1 were down-regulated in the testes of the tramadol-treated rabbits. On the other hand, pretreatment of rabbits with garlic, selenium, and/or garlic-selenium for 2 h before administration of tramadol restored the downregulated CYP 21A2 and 11A1 to their normal levels after 12 weeks of tramadol treatment. Activities of antioxidant enzymes including glutathione reductase, glutathione peroxidase, glutathione S-transferase, catalase, superoxide dismutase, and levels of glutathione were inhibited in the testes of tramadol-treated rabbits. On the other hand, free radical levels were significantly increased in the testes of tramadol-treated rabbits for 12 weeks. Interestingly, such changes in the activities of antioxidant enzymes as well as free radical levels caused by tramadol were restored to their normal levels in the rabbits pretreated with either selenium, garlic, and/or their combination. Histopathological investigations showed that tramadol caused substantial vacuolization with the presence of damaged immature spermatozoid in the testes. However, selenium and garlic treatments showed an increase in healthy sperm production with normal mitotic and meiotic divisions. The present study illustrated for the first time the mechanisms of low steroid hormone levels in the testes of tramadol-treated rabbits which could be due to the downregulation of CYPs proteins, induction of oxidative stress, and inhibition of antioxidant enzyme activities. In addition, the present data showed that such toxic effects of tramadol were attenuated and restored to their normal levels after pretreatment of rabbits with garlic, selenium, and/or their combination. This finding may pave the way for a new approach to reducing the toxicity of tramadol.

A humanized pattern of aromatase expression is associated with mammary hyperplasia in mice

Aromatase is essential for estrogen production and is the target of aromatase inhibitors, the most effective endocrine treatment for postmenopausal breast cancer. Peripheral tissues in women, including the breast, express aromatase via alternative promoters. Female mice lack the promoters that drive aromatase expression in peripheral tissues; thus, we generated a transgenic humanized aromatase (Arom(hum)) mouse line containing a single copy of the human aromatase gene to study the link between aromatase expression in mammary adipose tissue and breast pathology. Arom(hum) mice expressed human aromatase, driven by the proximal human promoters II and I.3 and the distal promoter I.4, in breast adipose fibroblasts and myoepithelial cells. Estrogen levels in the breast tissue of Arom(hum) mice were higher than in wild-type mice, whereas circulating levels were similar. Arom(hum) mice exhibited accelerated mammary duct elongation at puberty and an increased incidence of lobuloalveolar breast hyperplasia associated with increased signal transducer and activator of transcription-5 phosphorylation at 24 and 64 wk. Hyperplastic epithelial cells showed remarkably increased proliferative activity. Thus, we demonstrated that the human aromatase gene can be expressed via its native promoters in a wide variety of mouse tissues and in a distribution pattern nearly identical to that of humans. Locally increased tissue levels, but not circulating levels, of estrogen appeared to exert hyperplastic effects on the mammary gland. This novel mouse model will be valuable for developing tissue-specific aromatase inhibition strategies.

Predictors of breast discomfort among women initiating menopausal hormone therapy

OBJECTIVE

The aim of this study was to analyze the determinants of breast discomfort among postmenopausal women initiating menopausal hormone therapy (HT).

METHODS

We analyzed questionnaire, anthropometric, and serum estrone data from the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial, a randomized trial comparing placebo, conjugated equine estrogens (CEE) alone, or CEE with a progestogen (continuous or cyclical medroxyprogesterone acetate or cyclical micronized progesterone) among postmenopausal women. HT users could join the PEPI Trial after stopping HT for 2 months. We modeled the relation between smoking, body weight, alcohol consumption, age, quitting HT for the PEPI Trial, physical activity, and alpha-tocopherol consumption and new-onset breast discomfort at the 12-month follow-up among 662 participants without baseline breast discomfort.

RESULTS

The associations of new-onset breast discomfort with weight and with strenuous exercise varied by treatment assignment. Among women assigned to CEE + progestogen, strenuous exercise was associated with a 49% lower odds of new-onset breast discomfort (odds ratio, 0.51; 95% CI, 0.29-0.89; P = 0.02), whereas among women assigned to placebo or CEE alone, strenuous exercise was not significantly associated with new-onset breast discomfort. Surprisingly, among women taking CEE alone, each kilogram higher weight was associated with a 6% lower odds of new-onset breast discomfort (P = 0.04), whereas among women taking placebo, the association was in the opposite direction (P = 0.04). Adjustment for estrone level had negligible effects on odds ratios. alpha-Tocopherol intake, age, smoking, and alcohol intake were not significantly associated with new-onset breast discomfort in adjusted analyses.

CONCLUSIONS

Strenuous exercise and higher body weight may decrease the odds of new-onset breast discomfort among postmenopausal women initiating HT.

Analysis of estrogens in serum and plasma from postmenopausal women: past present, and future

Previous studies have shown that the selection of women who are at high breast cancer risk for treatment with chemoprevention agents leads to an enhanced benefit/risk ratio. However, further efforts to implement this strategy will require the development of new models to predict the breast cancer risk of particular individuals. Postmenopausal women with elevated plasma or serum estrogens are at increased risk for breast cancer. Therefore, the roles of various enzymes involved in the biosynthesis of estrogens in postmenopausal women have been reviewed in detail. In addition, the potential genotoxic and/or proliferative effects of the different estrogen metabolites as risk factors in the etiology of breast cancer have been examined. Unfortunately, much of the current bioanalytical methodology employed for the analysis of plasma and serum estrogens has proved to be problematic. Major advances in risk assessment would be possible if reliable methodology were available to quantify estradiol and its major metabolites in the plasma or serum of postmenopausal women. High performance liquid chromatography (HPLC) coupled with radioimmunoassay (RIA) currently provides the most sensitive and best validated immunoassay method for the analysis of estrone and estradiol in serum samples from postmenopausal women. However, inter-individual differences in specificity observed with many other immunoassays have caused significant problems when interpreting epidemiologic studies of breast cancer. It is almost impossible to overcome the inherent assay problems involved in using RIA-based methodology, particularly for multiple estrogens. For reliable measurements of multiple estrogens in plasma or serum, it will be necessary to employ stable isotope dilution methodology in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Extremely high sensitivity can be obtained with pre-ionized estrogen derivatives when employed in combination with a modern triple quadrupole mass spectrometer and nanoflow LC. Using [(13)C(6)]-estrone as the internal standard it has proved possible to analyze estrone as its pre-ionized Girard T (GT) derivative in sub-fg (low amol) amounts on column. This suggests that in the future it will be possible to routinely conduct LC-MS assays of multiple estrogen metabolites in serum and plasma at even lower concentrations than the current lower limit of quantitation of 0.4pg/mL (1.6pmol/L). The ease with which the pre-ionization derivatization strategy can be implemented will make it possible to readily introduce high sensitivity stable isotope dilution methodology in laboratories that are currently employing LC-MS/MS methodology. This will help conserve important plasma and serum samples as it will be possible to conduct high sensitivity analyses using low sample volumes.