Urinary 2/16 estrogen metabolite ratio levels in healthy women: a review of the literature

Effectiveness of 3,3'-Diindolylmethane Supplements on Favoring the Benign Estrogen Metabolism Pathway and Decreasing Body Fat in Premenopausal Women

The Estrogen Metabolites (2-hydroxyestrogens: 16α-hydroxyestrone) Urine Ratio (EMUR) has been negatively associated with breast cancer; Mexican women have a lower EMUR than other populations. We evaluated the effectiveness of 3,3'-diindolylmethane (DIM) supplementation on increasing EMUR in premenopausal women. A randomized, double-blind clinical trial (NCT02525159 at ClinicalTrial.gov) was carried out on 60 women with an EMUR below 0.9. Patients were assigned randomly to receive a placebo or 75 mg of DIM a day (administered as 300 mg of DIM-BR®) for 30 day. Urine samples were obtained at baseline, at 30 day of supplementation, and 30 day after finishing supplementation. A Mann-Whitney U test was used to compare the EMUR; an ANOVA was used to analyze differences in body composition. EMUR was analyzed using ESTRAMET™ kits. While DIM-treated subjects did not increase their EMUR at 30 day of supplementation (p > 0.05), there was a non-significant positive trend 30 day once supplementation ended (p = 0.06). The DIM group saw a more significant decrease in body fat percentage than the placebo group (p = 0.04). In premenopausal Mexican women, 75 mg of the daily DIM supplement was ineffective in increasing EMUR; further studies are needed to evaluate the effective dosage, time frames, and effect on body fat.

Associations of established breast cancer risk factors with urinary estrogens in postmenopausal women

PURPOSE

Circulating estrogens are an established risk factor for postmenopausal breast cancer (BCa). We describe the distribution of urinary estrogens, their metabolites, and relevant metabolic pathway ratios among healthy postmenopausal women and examine associations of several known BCa factors with these estrogen measures.

METHODS

Eligible postmenopausal women (n = 167) had no history of hormone use (previous 6 months) and cancer/metabolic disorders and had a body mass index (BMI) ≤ 35 kg/m². Estrogens were quantified in spot urine samples with liquid chromatography-high-resolution mass spectrometry and corrected for creatinine. We assessed overall distributions of estrogens and associations of age, BMI, race/ethnicity, parity/age at first birth, age at menarche, alcohol, and smoking with log-transformed estrogen measures using multivariate regression.

RESULTS

BMI was positively associated with estrone (β per unit = 0.04, 95% Confidence Interval [CI] 0.00; 0.07), combined parent estrogens (β = 0.04, 95% CI 0.01; 0.07), and E2:total estrogens (β = 0.04, 95% CI 0.02; 0.06), and inversely associated with 4-MeOE1 (β = - 0.17, 95% CI - 0.33; - 0.02), E3:parent estrogens (β = - 0.04, 95% CI - 0.07; - 0.00), and 16-pathway:parent (β = - 0.04, 95% CI - 0.07; - 0.01). Being African American vs. white was associated with higher levels of 4-MeOE1 (β = 3.41, 95% CI 0.74; 6.08), 17-epiE3 (β = 1.19, 95% CI 0.07; 2.31), 2-pathway:parent (β = 0.54, 95% CI 0.04; 1.04), and lower levels of E2:total estrogens (β = - 0.48, 95% CI - 0.83; - 0.13). Having < 7 alcohol drinks/week vs. none was associated with higher levels of 16-ketoE2 (β = 1.32, 95% CI 0.36; 2.27), 16-epiE3 (β = 1.02, 95% CI 0.24; 1.79), and 17-epiE3 (β = 0.55, 95% CI 0.02; 1.08). Smoking was positively associated with E3:parent (β = 0.29, 95% CI 0.01; 0.57), 16-pathway:parent (β = 0.25, 95% CI 0.01; 0.49), and inversely associated with estradiol (β = - 0.52, 95% CI - 0.93; - 0.10). As compared to nulliparous, parous women with age at first birth ≥ 25 years had lower levels of estrone, combined parent estrogens, 2-OHE1, and 2-OHE2.

CONCLUSION

Our findings suggest that BMI, race/ethnicity, and some reproductive and lifestyle factors may contribute to postmenopausal BCa through their effects on circulating estrogens.

LC-HRMS of derivatized urinary estrogens and estrogen metabolites in postmenopausal women

In order to undertake an epidemiologic study relating levels of parent estrogens (estrone and estradiol) and estrogen metabolites (EMs) to other breast cancer risk factors, we have optimized methods for EM quantification with ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). A two-step approach was adopted; the first step comprised method development and evaluation of the method performance. The second step consisted of applying this method to quantify estrogens in postmenopausal women and determine if the observed patterns are consistent with the existing literature and prior knowledge of estrogen metabolism. First, 1-methylimidazole-2-sulfonyl chloride (MIS) was used to derivatize endogenous estrogens and estrogen metabolites in urine from study participants. Since C18 reversed phase columns have not been able to separate all the structurally related EMs, we used a C18-pentafluorophenyl (PFP) column. The parent estrogens and EMs were baseline resolved with distinct retention times on this C18-PFP column using a 30 min gradient. This method was used to quantify the parent estrogens and 13 EMs in urine samples collected in an initial pilot study involving males as well as pre- and peri-menopausal females to assess a range of EM levels in urine samples and enable comparison to the previous literature for assay evaluation. Detection limits ranged from 1 - 20 pg/mL depending on the EM. We evaluated matrix effects and interference as well as the intra- and inter-batch reproducibility including hydrolysis, extraction, derivatization and LC-MS analysis using charcoal-stripped human urine as a matrix. Methods were then applied to the measurement of estrogens in urine samples from 169 postmenopausal women enrolled in an epidemiological study to examine relationships between breast cancer risk, the intestinal microbiome, and urinary EMs. The results from our cohort are comparable to previous reports on urinary EMs in postmenopausal women and enabled thorough evaluation of the method.

Elevation of C-reactive protein during the luteal phase in healthy adolescents

INTRODUCTION

Variations in inflammatory markers have been reported in adult women during the luteal phase, but whether these findings are observed during adolescence is unknown. We postulate that higher ultrasensitive C-reactive protein (usCRP) and lower 2-hydroxyestrone (2OHE) levels, an estrogen metabolite with cardioprotective actions, are present during the luteal phase in young women.

AIM

To evaluate usCRP levels during the menstrual cycle and to determine its association with 2OHE and 16α-hydroxyestrone (16OHE) in adolescents.

METHODS

Healthy postmenarcheal adolescents (N = 37) were studied during one menstrual cycle in follicular phase (FP) and luteal phase-like period (LP-L).

RESULTS

Elevations in usCRP levels in the LP-L were observed in the entire group and in anovulatory cycles (1.9 ± 1.1 mg/L in FP to 2.5 ± 1.8 mg/L in LP-L; p < 0.0001). Increases in estrone, estradiol, free and bioavailable estradiol, testosterone, usCRP and 2OHE levels were observed in LP-L compared with FP (p < 0.01), with a borderline elevation in IFG-I levels (p = 0.06).

CONCLUSIONS

We report an elevation of usCRP and 2OHE levels during the luteal phase in healthy adolescents. Elevations of this inflammatory marker in anovulatory adolescents without an increase in 2OHE may play a role in metabolic risks associated with chronic anovulation.

Fruit intake associated with urinary estrogen metabolites in healthy premenopausal women

Urinary concentrations of 2:16-hydroxyestrone (2:16-OHE₁) approximate concentrations of 2-OHE₁ and 16α -OHE₁ in breast tissue. As estrogens are purported to be involved in breast cancer development, the 2:16-OHE₁ ratio can provide an indication of estrogen metabolite exposure in the breast. With prior studies observing associations between urinary estrogen metabolites and dietary intake of fruits, vegetables, and fiber ascertained from food questionnaires, we examined associations between dietary factors ascertained through 3-day food records and urinary 2:16-OHE₁ in 191 pre-menopausal healthy women. Fruit consumption was positively associated with 2:16-OHE₁ after adjustment for total energy, ethnicity, body mass index, parity, smoking history, and serum estradiol (p= 0.003). Fruit consumption was positively associated with 2- OHE₁ concentrations (p=0.006), but was not associated with 16α-OHE₁ (p=0.92). The Musaceae botanical grouping (comprised primarily of bananas) was positively associated with the 2:16-OHE₁ ratio, and Rosaceae (comprised of citrus fruits) and Musaceae botanical groupings were positively associated with 2-OHE₁ (but not 16α-OHE₁) concentrations, after adjustment for confounders. Our data suggest that dietary fruit intake is associated with urinary 2- OHE₁ and the 2:16-OHE₁ ratio and that breast tissue exposure to estrogen metabolites may thus be influenced by diet.

Impact of sex hormone metabolism on the vascular effects of menopausal hormone therapy in cardiovascular disease

Epidemiological studies have shown that cardiovascular disease (CVD) is less common in pre-menopausal women (Pre-MW) compared to men of the same age or post-menopausal women (Post-MW), suggesting cardiovascular benefits of estrogen. Estrogen receptors (ERs) have been identified in the vasculature, and experimental studies have demonstrated vasodilator effects of estrogen/ER on the endothelium, vascular smooth muscle (VSM) and extracellular matrix. Several natural and synthetic estrogenic preparations have been developed for relief of menopausal vasomotor symptoms. However, whether menopausal hormone therapy (MHT) is beneficial in postmenopausal CVD remains controversial. Despite reports of vascular benefits of MHT from observational and experimental studies, randomized clinical trials (RCTs), such as the Heart and Estrogen/progestin Replacement Study (HERS) and the Women's Health Initiative (WHI), have suggested that, contrary to expectations, MHT may increase the risk of CVD. These discrepancies could be due to agerelated changes in sex hormone synthesis and metabolism, which would influence the effective dose of MHT and the sex hormone environment in Post-MW. Age-related changes in the vascular ER subtype, structure, expression, distribution, and post-ER signaling pathways in the endothelium and VSM, along with factors related to the design of RCTs, preexisting CVD condition, and structural changes in the blood vessels architecture have also been suggested as possible causes of MHT failure in CVD. Careful examination of these factors should help in identifying the causes of the changes in the vascular effects of estrogen with age. The sex hormone metabolic pathways, the active versus inactive estrogen metabolites, and their effects on vascular function, the mitochondria, the inflammatory process and angiogenesis should be further examined. Also, the genomic and non-genomic effects of estrogenic compounds should be viewed as integrated rather than discrete responses. The complex interactions between these factors highlight the importance of careful design of MHT RCTs, and the need of a more customized approach for each individual patient in order to enhance the vascular benefits of MHT in postmenopausal CVD.

Estrogen metabolite ratio: Is the 2-hydroxyestrone to 16α-hydroxyestrone ratio predictive for breast cancer?

Experimental studies have shown that two main estrogen metabolites hydroxylated by CYP1A1 and CYP1B1 in the breast differentially affect breast cell proliferation and carcinogenesis. Although 16α-hydroxyestrone (16αOHE1) exerts estrogenic activity through covalent estrogen receptor (ER) binding, 2-hydroxyestrone (2OHE1) presumably has antiestrogenic capabilities. The ratio of 2OHE1 to 16αOHE1 represents the relative dominance of one pathway over the other and is believed to be modifiable by diet. It was hypothesized that women with or at high risk of breast cancer have a lower estrogen metabolite ratio (EMR) compared with women without breast cancer. We conducted a systematic review on the EMR as a predictor for breast cancer. A total of nine studies (six prospective and three retrospective) matched our inclusion criteria, comprising 682 premenopausal cases (1027 controls) and 1189 postmenopausal cases (1888 controls). For the highest compared with the lowest quantile of urinary EMR, nonsignificant associations suggested at best a weak protective effect in premenopausal but not in postmenopausal breast cancer (range of odds ratios: 0.50-0.75 for premenopausal and 0.71-1.31 for postmenopausal). Circulating serum/plasma EMR was not associated with breast cancer risk. Associations were inconclusive for receptor subtypes of breast cancer. Uncontrolled factors known to be involved in breast carcinogenesis, such as 4-hydroxyestrone (4OHE1) concentration, may have confounded results for EMR. Results of the prospective studies do not support the hypothesis that EMR can be used as a predictive marker for breast cancer risk. Future research should concentrate on profiles of estrogen metabolites, including 4OHE1, to gain a more complete picture of the relative importance of single metabolites for breast cancer.