Estrogen receptor alpha and beta polymorphisms: is there an association with bone mineral density, plasma lipids, and response to postmenopausal hormone therapy?

The influence of ESR1 polymorphisms on selected hormonal, metabolic and mineral balance markers in women with hyperandrogenism

Hyperandrogenism is the most common endocrine disorder in women, characterized by an imbalance in normal estrogen and androgen levels in the blood. Androgens influence bone mineral density, body mass composition, muscle mass, mental state, and the regulation of sexual function.. The aim of the study was to assess the effect of estrogen receptor α gene (ESR1) polymorphisms on selected markers of bone metabolism and hormonal parameters in women with hyperandrogenism. The study group included 80 young women with hyperandrogenism who underwent measurements of bone mineral density (BMD), and determination of hormonal and metabolic parameters. Enzyme immunoassays were used to measure leptin, sRANKL (soluble receptor activator of nuclear factor-kB ligand), osteoprotegerin and 25-OH vitamin D total levels. An analysis of ESR1 gene polymorphisms was performed using the real-time PCR method. A relationship was demonstrated between the concentration of free estradiol (FEI) and the concentration of 17-OH-progesterone, and the ESR1 gene polymorphisms: rs3020314 (p = 0.031, p = 0.026 respectively) and rs1884051 (p = 0.033, p = 0.026 respectively). In conclusion, the ESR gene polymorphisms may be associated with hormonal disturbances in the concentration of estrogens and androgens, in hyperandrogenism in young women which may indirectly affect bone mineral density. However, no statistically significant relationships between the studied polymorphisms and the selected parameters of mineral metabolism have been demonstrated..

Association of estrogen receptor β polymorphisms with posterior tibial tendon dysfunction

Posterior tibial tendon (PTT) dysfunction is three times more common in females, and some patients may have a predisposition without a clinically evident cause, suggesting that individual characteristics play an important role in tendinopathy. The present study investigated the association of rs4986938 (+ 1730G > A; AluI RFLP) and rs1256049 (- 1082G > A; RsaI RFLP) single nucleotide polymorphisms (SNPs) of estrogen receptor-beta (ER-β) gene with PTT dysfunction. A total of 400 participants were recruited. The PTT dysfunction group: these patients underwent surgery, with PTT tendinopathy confirmed by histopathology and magnetic resonance image (MRI). The control group was composed of participants with no clinical or MRI evidence of PTT dysfunction. Each group was composed of 100 postmenopausal women, 50 premenopausal women, and 50 men. Genomic DNA was extracted from saliva samples, and genotypes were obtained by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Concerning the ER-β SNP rs4986938, there were significant differences in the frequencies of alleles between test and control groups of all the cases, only postmenopausal women and only men (p < 0.0001, p = 0.0016 and p = 0.0001). Considering the PTT dysfunction group and comparing postmenopausal women versus premenopausal women adding men, the analysis showed significant differences in the allelic distribution (p = 0.0450): the allele A in postmenopausal women is a risk factor. The ER-β SNP rs1256049 did not show differences in the frequencies of alleles and genotypes between groups. The ER-β SNP rs4986938, but not ER -β SNPs rs1256049, may contribute to PTT insufficiency in the Brazilian population, with additional risk in postmenopausal women. Addition, in men the genetic factor could be more determinant.

Estrogen receptor α and β gene polymorphism in relation to bone mineral density and lipid profile in Northeast Indian women

Estrogen regulates bone homeostasis and has a cardio-protective effect. Its physiological functions are mediated through receptors (ER) whose expression can be regulated by presence or absence of polymorphisms. However, the association between ER polymorphisms and BMD as well as lipids are inconsistent. The aim of the study was to investigate whether polymorphisms in ESR are associated with bone mineral density (BMD) and lipids in a cohort of Indian women. We studied PvuII, XbaI polymorphisms in ESR1 and AluI, RsaI polymorphisms in ESR2 genes and their association with bone mineral density (BMD) and lipids in premenopausal (n = 293, mean age: 33.01 ± 5.23 years) and postmenopausal (n = 145, mean age: 56.91 ± 7.1 years) women from Northeast India. AluI and RsaI polymorphisms in ESR2 gene were associated with BMD in postmenopausal women. Logistic regression analysis adjusted for age, BMI, tobacco and alcohol consumption revealed that xx genotype in XbaI polymorphism is associated with osteopenia at spine (OR = 3.3, 95% CI = 1.067-10.204) in postmenopausal women suggesting that allele X is protective (OR = 0.419, 95% CI = 0.177-0.991). Genotype aa in AluI polymorphism, seemed to be protective (OR = 0.092 for osteopenia; OR = 0.152 for osteoporosis) at spine whereas A allele was associated with osteopenia at femur (OR = 2.123, 95% CI = 1.079-4.166) in postmenopausal women. Allele r of RsaI polymorphism, was associated with osteoporosis at spine (OR = 3.222, 95% CI = 1.302-7.96). Thus, AIuI polymorphism of ESR2 gene was associated with spinal and femoral BMD whereas RsaI only with spinal BMD in postmenopausal women and ESR genotypes were not associated with lipids.

The estrogen receptor 1 gene affects bone mineral density and osteoporosis treatment efficiency in Slovak postmenopausal women

BACKGROUND

The study investigated the associations of rs9340799:A > G (XbaI) and rs2234693:T > C (PvuII) polymorphisms in the estrogen receptor 1 gene (ESR1) with femoral neck (BMD-FN) and lumbar spine bone mineral density (BMD-LS), biochemical markers of bone turnover, calcium and phosphate levels, fracture prevalence, and a response to two types of anti-osteoporotic therapy in postmenopausal women from southern Slovakia.

METHODS

We analysed 343 postmenopausal Slovak women (62.40 ± 0.46 years). The influence of rs9340799 (AA vs. AG + GG) and rs2234693 (TT vs. TC + CC) genotypes on BMD and biochemical markers was evaluated by covariance analysis adjusted for age and BMI. Binary logistic regression was used to evaluate the genotype effect on fracture prevalence. Pharmacogenetic part of the study included women who received a regular therapy of HT (17ß estradiol with progesterone; 1 mg/day for both; N = 76) or SERMs/raloxifene (60 mg/day; N = 64) during 48 months. The genotype-based BMD change was assessed by variance analysis for repeated measurements.

RESULTS

Women with AA genotype of rs9340799 had higher BMD-FN (+ 0.12 ± 0.57 of T-score) and BMD-LS (+ 0.17 ± 0.08 of T-score) in comparison with AG + GG. The rs2234693 polymorphism did not affect any of the monitored parameters. No effect of any ESR1 polymorphisms was found on fracture prevalence. Both types of anti-osteoporotic therapy had a positive effect on BMD improvement in FN and LS sites. Considering the effect of the ESR1 gene within the HT, the subjects with rs9340799/AA genotype showed worse response than those with GG genotype (- 0.26 ± 0.10 of BMD-FN T-score; - 0.35 ± 0.10 of BMD-LS T-score) and also with AG genotype (- 0.22 ± 0.08 of BMD-LS T-score). The rs2234693/TT genotype responded poorer in BMD-LS in comparison with TC (- 0.22 ± 0.08 of T-score) and CC (- 0.35 ± 0.09 of T-score). The effect of the ESR1 gene on raloxifene therapy was reported only in BMD-LS. Subjects with rs9340799/AA genotype had a - 0.30 ± 0.11 of T-score worse response compared to AG genotype. The rs2234693/TT genotype showed - 0.39 ± 0.11 and - 0.46 ± 0.15 lower T-scores in comparison with TC and CC genotypes, respectively.

CONCLUSIONS

The rs9340799 polymorphism may contribute to decreased BMD in postmenopausal women from southern Slovakia; however, this is not related to higher fracture prevalence. Concurrently, both polymorphisms affected a response to analysed anti-osteoporotic therapies.

Polymorphisms in period genes and bone response to hormone therapy in postmenopausal Korean women

OBJECTIVE

In this study, we aimed to explore the association between polymorphisms in the period (PER) gene and bone response to hormone therapy (HT) in postmenopausal Korean women.

METHODS

The PER1 c.2284C > G, c.2247C > T, PER2 c.3731G > A, PER3 c.2592G > A, c.3083T > C polymorphisms, and PER3 54bp variable number of tandem repeats (VNTR) were analyzed in 509 postmenopausal Korean women who received HT. Bone mineral density (BMD) at the lumbar spine and femoral neck before and after 1 year of HT and serum levels of osteoprotegerin (OPG), soluble receptor activator of the nuclear factor-κB ligand (sRANKL) and bone turnover markers were measured after 6 months of HT.

RESULTS

The PER1 c.2884 C > G polymorphism and PER3 54bp VNTR were associated with annual percent changes in BMD of the femoral neck after 1 year of HT (p < 0.05). Changes in BMD at the femoral neck in the non-CC genotype of the PER1 c.2884C > G polymorphism and in the 4-repeat homozygote of PER3 54bp VNTR were significantly lower than those in CC genotype and non-4-repeat homozygote, respectively. The PER1 c.2884C > G polymorphism was associated with the non-response (>3% BMD loss/year after HT) of HT. The non-CC genotype of the PER1 c.2884C > G polymorphism showed a 1.92-times higher risk of non-response at the lumbar spine and/or femoral neck (p = 0.01) compared with the CC genotype. No significant changes in bone markers after 6 months of HT were noted according to the PER1 c.2884C > G polymorphism.

CONCLUSIONS

The PER1 c.2884C > G polymorphism may be associated with risk of non-response to HT in postmenopausal Korean women.

Pharmacogenomics of osteoporosis: a pathway approach

Osteoporosis is frequent in postmenopausal women and old men. As with other prevalent disorders, it is the consequence of complex interactions between genetic and acquired factors. Candidate gene and genome-wide association studies have pointed to several genes as determinants of the risk of osteoporosis. Some of them were previously unsuspected and may help to find new therapeutic targets. Several drugs already available are very effective in increasing bone mass and decreasing fracture risk. However, not all patients respond properly and some of them suffer fragility fractures despite therapy. Investigators have tried to identify the genetic features influencing the response to antiosteoporotic therapy. In this article we will review recent data providing insight into new genes involved in osteoporosis and the pharmacogenetic data currently available.

PvuII and XbaI polymorphisms of estrogen receptor-α and the results of estroprogestagen therapy in girls with functional hypothalamic amenorrhea - preliminary study

INTRODUCTION

The aim of this study was the long-term prospective evaluation of the effects of estroprogestagen (EP) therapy on the bone mineral density (BMD) of girls with functional hypothalamic amenorrhea (FHA) carrying various PvuII and XbaI polymorphisms of ER-α.

MATERIAL AND METHODS

Prospective observation included 84 FHA girls and 50 controls. The FHA patients were subjected to 4-year sequential therapy with 17β estradiol (2 mg from the 2(nd) to 25(th) day of the menstrual cycle) and dydrogesterone (10 mg from the 16(th) to the 25(th) day). Hormonal parameters, serum concentration of the bone fraction of alkaline phosphatase (BALP), urine concentration of cross-linked n-telopeptide of type I collagen (Ntx) and BMD were determined before and after the treatment.

RESULTS

Six-month treatment resulted in a marked increase in estradiol (p = 0.001), testosterone and prolactin levels (p = 0.01 both) and a significant decrease in BALP and Ntx (p = 0.001 both). Patients with the PP polymorphism had significantly lower baseline BMD compared to carriers of other polymorphic variants of PvuII (p = 0.003). A significant increase in BMD was observed throughout the entire therapy period, with no significant differences in the yearly dynamics of BMD changes observed amongst various polymorphic variants and haplotypes of ER-α.

CONCLUSIONS

The EP therapy is effective in the treatment of BMD disorders associated with FHA, and treatment results do not depend on PvuII and XbaI polymorphisms of ER-α.

Serum lipid levels and bone mineral density in Greek postmenopausal women

Contradictory results have been reported regarding a relationship between serum lipid levels and bone mineral density. The purpose of this study was to further investigate a possible relationship between those parameters in Greek postmenopausal women. A total of 591 patients followed at a tertiary hospital were examined for seven different lipid factors in relation to dual-emission X-ray absorptiometry measurements at the lumbar spine. Lipoprotein-a was the only lipid measurement that univariately showed an almost significant trend of association with bone mass category (analysis of variance [ANOVA] p value 0.062 for Ln(Lipoprotein-a)). In multiple regression, it was noted that a non-significant negative trend of association of high density lipoprotein (HDL) cholesterol and Apolipoprotein AI with lumbar T-score (p value 0.058 and 0.075, respectively). In age subgroup analysis, Lipoprotein-a and Ln(Lipoprotein-a) presented a negative correlation with lumbar T-score for women with age ≥ 53 years (p value 0.043 and 0.070, respectively), while a negative correlation of HDL and Apolipoprotein AI levels with lumbar T-score remained in women with age < 53 years (p value 0.039 and 0.052, respectively). The findings do not support a strong relationship between lipid levels and bone mass measurements.

Are polymorphisms in oestrogen receptors genes associated with lipid levels in response to hormone therapy?

BACKGROUND

Polymorphisms in the oestrogen receptor 1 (ESR1) and oestrogen receptor 2 (ESR2) genes are associated with intermediate or endpoint markers of cardiovascular disease and with the efficacy of postmenopausal hormone therapy (HT). Contradictory findings have been described in the past and the role of these genetics variants remains unclear.

METHODS

A cross-sectional study was carried out with 266 postmenopausal women, of whom 115 received oral HT (HT+) and 151 did not receive any HT (HT-). We analysed three single-nucleotide polymorphisms (SNPs) in ESR1 (rs1801132, rs7757956 and rs2813544) and two in ESR2 (rs3020450 and rs7154455) and derived haplotypes with three additional polymorphisms that had been previously investigated by our group (ESR1 rs2234693 and ESR2 rs1256049 and rs4986938).

RESULTS

The ESR1 rs2813544 polymorphism was associated with low-density lipoprotein cholesterol (LDL-C) in HT+ postmenopausal women (p = 0.044; pC = 0.388), while one ESR2 gene haplotype was associated with total cholesterol (T-chol) (p = 0.015; pC = 0.090) and LDL-C in HT+ postmenopausal women (p = 0.021; pC = 0.126).

CONCLUSION

Our findings suggest that, in HT+ postmenopausal women, the rs2813544 polymorphism may influence LDL-C levels and, as previously described, ESR2 rs1256049 is associated with T-chol and LDL-C. No previous study has investigated the association of this SNP set with lipoprotein levels in women while taking into account the hormonal status of the patients.

Association of estrogen receptor beta variants and serum levels of estradiol with risk of colorectal cancer: a case control study

Background

Endogenous estrogens may play a vital role in colorectal tumorigenesis. Estrogen receptor beta is the predominant subtype which mediates the biological effect of estrogens, while loss of expression of estrogen receptor beta has been indicated as a common step in the development of colorectal cancer (CRC). Epidemiological studies have revealed several functional polymorphisms of estrogen receptor beta (ESR2) for cancer risk, but relevant study in CRC is limited, particularly in men. This study aimed to investigate the association of circulating estradiol and variations of ESR2 with CRC risk in men.

Methods

We initiated a case–control study consisting of 390 patients with CRC and 445 healthy controls in men only. We genotyped ESR2 single nucleotide polymorphisms (SNPs) rs1256049 and rs4986938 and measured serum estradiol concentration using chemilluminescence immunoassay. Multivariable logistic regression model was performed to evaluate the associations between these variables and CRC risk.

Results

ESR2 rs1256049 CT/TT genotypes were associated with reduced risk of CRC (odds ratio [OR], 0.7, 95% confidence interval [CI], 0.5–1.0), while rs4986938 CT/TT genotypes were associated with increased risk of CRC (OR, 1.5, 95% CI, 1.0–2.1). In addition, the CRC risk increased with the number of risk genotypes of these two SNPs in a dose–response manner (P_trend, 0.003). Specifically, subjects carrying risk genotypes of both SNPs had the highest risk of CRC (OR, 2.0, 95% CI, 1.3–3.3.). Moreover, serum estradiol concentration alone was associated with risk of CRC in men (OR, 1.2, 95% CI, 1.0–1.3). However, individuals presenting both rs4986938 CT/TT genotypes and high level of serum estradiol had a high risk of CRC (OR, 2.3, 95% CI, 1.4–3.9), compared with those presenting CC genotype and low level of serum estradiol. The similar joint results were not observed for SNP rs1256049.

Conclusions

These results suggest that endogenous estrogen and genetic variations in ESR2 may individually, or more likely jointly, affect CRC risk in male Han Chinese population, while larger studies are needed to validate our findings.

Hormone treatment, estrogen receptor polymorphisms and mortality: a prospective cohort study

BACKGROUND

The association between hormone treatment (HT) and mortality remains controversial. This study aimed to determine whether the risk of mortality associated with HT use varies depending on the specific characteristics of treatment and genetic variability in terms of the estrogen receptor.

METHODOLOGY/PRINCIPAL FINDINGS

A prospective, population-based study of 5135 women aged 65 years and older who were recruited from three cities in France and followed over six years. Detailed information related to HT use was obtained and five estrogen receptor polymorphisms were genotyped. The total follow-up was 25,436 person-years and during this time 352 women died. Cancer (36.4%) and cardiovascular disease (19.3%) were the major causes of death. Cox proportional hazards models adjusted for age, education, centre, living situation, comorbidity, depression, physical and mental incapacities, indicated no significant association between HT and mortality, regardless of the type or duration of treatment, or the age at initiation. However, the association between HT and all-cause or cancer-related mortality varied across women, with significant interactions identified with three estrogen receptor polymorphisms (p-values = 0.004 to 0.03) in adjusted analyses. Women carrying the C allele of ESR1 rs2234693 had a decreased risk of all-cause mortality with HT (HR: 0.42, 95% CI: 0.18-0.97), while in stark contrast, those homozygous for the T allele had a significantly increased risk of cancer-related mortality (HR: 3.18, 95% CI: 1.23-8.20). The findings were similar for ESR1 rs9340799 and ESR2 rs1271572.

CONCLUSIONS/SIGNIFICANCE

The risk of mortality was not associated with HT duration, type or age at initiation. It was however not equal across all women, with some women appearing genetically more vulnerable to the effects of HT in terms of their estrogen receptor genotype. These findings, if confirmed in another independent study, may help explain the differential susceptibility of women to the beneficial or adverse effects of HT.

Estrogen receptor alpha gene variants and major depressive episodes

BACKGROUND

Despite evidence of estrogen's mood-enhancing effects, the association between estrogen receptor (ER) gene variants and lifetime major depression has been insufficiently studied.

METHODS

3987 community-dwelling women aged 65years and over were recruited in France as part of the Three City Study. Current and past major depressive disorders (MDD) were diagnosed using the Mini-International Neuropsychiatry Interview, according to DSM-IV criteria. The association between two common estrogen receptor alpha (ESR1) polymorphisms with lifetime MDD was examined using adjusted logistic regression models, taking into account the age at first depressive episode and the recurrence of depression.

RESULTS

Women homozygous for the variant G allele of ESR1 rs9340799 had a 1.6-fold increased risk of MDD across their lifetime compared with women who were homozygous for the A allele (p=0.009). There was a similar non-significant trend for the C allele of rs2234693 being associated with an increased risk (p=0.09). Polytomous regression analysis further indicated that the GG genotype of rs9340799 was specifically associated with an increased risk of recurrent depressive episodes, regardless of the age at first onset of depression relative to the menopause.

LIMITATIONS

The duration and severity of depressive episodes was not considered in the analysis.

CONCLUSIONS

This is the first study to examine the association between ESR1 gene variants and lifetime MDD. Our findings indicate a significant association between common variants and the risk of recurrent depressive episodes. This suggests that certain depressed women could be most responsive to hormone-based treatment.

Short-term hormone therapy improves sCD40L and endothelial function in early menopausal women: potential role of estrogen receptor polymorphisms

OBJECTIVE

Hormone therapy (HT) has been suggested to improve vascular function and inflammation in menopausal women, although not consistently. We aimed to investigate the effects of HT on endothelial function and inflammation, especially sCD40L, in early menopausal women, and the effect of common estrogen receptor (ER) polymorphisms on vascular responses to HT.

STUDY DESIGN

Eighty-four early menopausal women (<3 years in menopause) with menopausal complaints eligible for HT. Forty women received transdermal 17β-estradiol plus cyclical micronized progesterone for 3 months while 44 did not (controls).

MAIN OUTCOME MEASURES

Brachial artery flow-mediated dilation (FMD) and vascular inflammation markers (sICAM, sP-Selectin and sCD40L). Genetic polymorphisms of ERα (PvuII 454-397T>C and XbaI 454-351A>G) and ERβ (AluI 1730A>G) were also assessed.

RESULTS

The two groups did not differ at baseline. Following HT, vasomotor complaints' severity, blood pressure, LDL, sCD40L, sICAM and sP-Selectin decreased and FMD increased compared to controls (P<0.05 for all). ERβ AluI A allele presence was the most important independent predictor of HT-induced increase in FMD while ERα XbaI A allele was the only independent predictor of decrease in sCD40L.

CONCLUSIONS

Short-term HT in early menopausal women improved endothelial function and inflammation. Specific ER polymorphisms that were found to be main determinants of HT-induced effects on endothelium could identify subgroups of women who may benefit the most from HT.

Estrogen receptor gene variants are associated with anxiety disorders in older women

BACKGROUND

Estrogen is thought to play a key role in anxiety, but it remains unknown whether genetic variants in the estrogen receptors (ERs) can influence the risk of anxiety. This study investigated whether ESR1 and ESR2 gene variants were associated with specific anxiety disorders in postmenopausal women and evaluated the potential modifying effect of hormone treatment (HT) on these associations.

METHODS

One thousand and ninety-two community-dwelling women aged 65 years and older were recruited as part of the ESPRIT Study in Montpellier, France. Anxiety was assessed using the Mini-International Neuropsychiatry Interview (MINI), according to DSM-IV criteria. Two ESR1 and three ESR2 polymorphisms were genotyped.

RESULTS

The most common anxiety disorders were phobia (14.2%) and generalised anxiety disorder (GAD, 8%). The A allele of ESR2 rs1256049 was associated with an increased risk of GAD [OR: 2.06, 95% CI: 1.09-3.87], while both ESR1 polymorphisms were specifically associated with phobia. The C allele of ESR1 rs2234693 decreased the risk of phobia by 42% [95% CI: 0.41-0.83], and this remained significant even after Bonferroni correction. The G allele of ESR1 rs9340799 was associated with a 31% decreased phobia risk [95% CI: 0.49-0.96]. There was also evidence of a significant gene-environment interaction, where only women who were currently using HT had a reduced risk of phobia with these ESR1 gene variants.

CONCLUSIONS

This study confirms earlier findings of an association between ESR1 and global anxiety in older women, however these associations varied depending on the anxiety syndrome and the use of HT. The results also suggest that the ESR2 may contribute to the genetic vulnerability to GAD, but these findings require further confirmation.

Oestrogen receptor polymorphisms and late-life depression

BACKGROUND

Evidence suggests a role for oestrogen in depression but the involvement of oestrogen receptor polymorphisms remains unknown.

AIMS

To determine the association between oestrogen receptor polymorphisms and late-life depression and the modifying effect of hormone treatment.

METHOD

Depression was assessed using the Mini-International Neuropsychiatric Interview, according to DSM-IV criteria and the Centre for Epidemiologic Studies - Depression Scale. The association between oestrogen receptor α and β (ER-α and ER-β) polymorphisms with severe depression was examined in 6017 community-dwelling elderly people using multivariate logistic regression.

RESULTS

In women, the ER-α rs2234693 and rs9340799 polymorphisms were significantly associated with the risk of late-life depression. The A allele of ER-β rs1256049 increased the risk of depression, but only for non-current users of hormone treatment. In men, only the ER-β rs4986938 polymorphism showed a weak association with depression risk.

CONCLUSIONS

Oestrogen receptor polymorphisms are associated with severe late-life depression risk in women only.

Association between Wnt signaling pathway gene polymorphisms and bone response to hormone therapy in postmenopausal Korean women

OBJECTIVE

The aim of this study was to explore the association between Wnt signaling pathway gene polymorphisms and response to hormone therapy (HT) as related to bone mineral density (BMD) in postmenopausal Korean women.

METHODS

The BMD and serum levels of osteoprotegerin, the soluble receptor activator of the nuclear factor κB ligand, and bone turnover markers were measured in 308 postmenopausal women receiving sequential estrogen + progestogen therapy. Results were analyzed according to the low-density lipoprotein receptor--related protein (LRP5) 5 c.266A > G, c.3893C > T, frizzled receptor 6 gene c.1033A > C, axin II c.148C > T, adenomatous polyposis coli c.5645T > A, and T-cell factor 1 c.766G > A polymorphisms.

RESULTS

The rates of 1-year changes in BMD and changes at 6 months in osteoprotegerin, soluble receptor activator of the nuclear factor κB ligand, and bone turnover markers after HT did not differ significantly between all single and haplotype genotypes of the genes studied. When a nonresponder was defined as a woman who had lost more than 3% of BMD per year after HT, women with T allele of the LRP5 c.3893C > T polymorphism showed a significantly higher risk of nonresponse at both the lumbar spine and femoral neck than did women with C allele. The risk of nonresponse at the lumbar spine was significantly higher in women with G allele of the LRP5 c.266A > G polymorphism than that in women with A allele, and the c.266G/c.3893T (GT) haplotype allele showed a similar trend.

CONCLUSIONS

The LRP5 c.266A > G and c.3893C > T polymorphisms may be associated with risk of nonresponse to HT in postmenopausal Korean women.

Association between ER-α polymorphisms and bone mineral density in patients with Turner syndrome subjected to estroprogestagen treatment--a pilot study

Reduced bone mineral density (BMD) is present in many women with Turner syndrome (TS), and hypo-estrogenism is known to play a vital role in bone mineralization disturbances. It has been suggested that genetic factors play an important role in the regulation of BMD. The aim of this study was to analyze the association between Pvu II and XbaI ER-α polymorphisms and BMD in TS patients subjected to estroprogestagen (EP) treatment. Thirty-two TS patients aged 17-38 (mean age 22.7 ± 8.2) along with 82 healthy controls were the subjects for this study. Baseline values of hormonal parameters, BMD and bone density markers were measured in the subjects. Subsequently, TS patients underwent 4 years of EP therapy. The results of laboratory parameters and BMD were analyzed in regard to PvuII and XbaI polymorphic variants of the ER-α gene. The increase in BMD of TS subjects was the highest in the 1st (7.5%, p = 0.013) and 2nd (6.6%, p = 0.008) years of treatment. Four years of EP therapy was reflected by a significant increase in BMD z-scores in patients with xx and Xx genotypes of the XbaI gene and in those with with the pp and Pp genotypes of PvuII. In patients with haplotypes other than XXPP, BMD z-scores were significantly higher compared to their baseline after 2 (p = 0.002), 3 (p < 0.001) and 4 (p < 0.001) years of treatment. In conclusion, genotypes xx and pp were shown to be prognostic markers of a good response to EP treatment, whereas the XXPP haplotype carriers were revealed to have the risk factors for insufficient responsiveness against EP treatment in BMD control.

The effect of ESR1 and ESR2 gene polymorphisms on the outcome of rheumatoid arthritis treatment with leflunomide

AIM

Leflunomide is the drug used in the therapy for rheumatoid arthritis (RA). Previous studies indicated that the efficacy of the therapy with antirheumatic drugs is more effective in men than in women. Moreover, estrogens can decrease the anti-inflammatory action of leflunomide. Estrogens act through the estrogen receptors ESR1 and ESR2. In ESR1 and ESR2 genes, several polymorphisms have been detected. The aim of the present study was to examine the association between polymorphisms in the ESR1 and ESR2 genes and the response to treatment of RA patients with leflunomide.

MATERIALS & METHODS

The study was carried out on 115 women, mean age 54.1 ± 11.0 years, diagnosed with RA and treated with leflunomide (20 mg daily).

RESULTS

Our results indicated a better response to treatment in patients with ESR1 rs9340799 AA and rs2234693 TT genotypes after 12 months of therapy. In these patients, the improvement of erythrocyte sedimentation rate, patient's global assessment of disease activity on a 100 mm visual analog scale and disease activity score values was greater than in patients with other genotypes. The ESR1 rs9340799-rs2234693 A-T haplotype was associated with a better response to treatment, the G-C haplotype with a worse response and the A-C haplotype was neutral. There were no statistically significant associations of response to treatment with ESR2 gene rs4986938 and rs1256049 polymorphisms.

CONCLUSION

The results of the present study suggest that ESR1 gene polymorphisms in females with RA may be associated with the response to treatment with leflunomide.

Effect of estrogen receptor β A1730G polymorphism on ABCA1 gene expression response to postmenopausal hormone replacement therapy

The estrogen receptor β (ERβ) mediates the action of estrogen on metabolism of lipids and lipoprotein. Therefore, its gene is a promising candidate gene for cardiovascular disease. The aim of the present study was to investigate whether the ERβ A1730G polymorphism modifies the metabolic response to hormone replacement therapy (HRT) in postmenopausal women. The population included 60 normolipidemic postmenopausal women with equal numbers of each A1730G genotype followed during a 90-day experimental period. All subjects received oral estrogen together with a progestin therapy during the HRT. ABCA1 gene expression and serum lipid and lipoprotein concentrations were measured at the beginning and end of the HRT trial. At baseline, ABCA1 gene expression, lipid or lipoprotein concentrations were not significantly different among the ERβ A1730G genotype groups. After HRT, however, subjects with GG genotype had a greater increase in ABCA1 gene expression (p = 0.002) and a trend toward greater increase in apoA-I (p = 0.058) than subjects carrying the A allele. An interaction effect between genotype and HRT effect was observed on ABCA1 gene expression. In conclusion, the positive changes of ABCA1 gene expression and apoA-I were affected by the ERβ A1730G polymorphism in women taking estrogen-progesterone therapy.

Genotypes and haplotypes of the estrogen receptor genes, but not the retinoblastoma-interacting zinc finger protein 1 gene, are associated with osteoporosis

Osteoporosis is a common age-related disease with a strong genetic influence. Polymorphisms of ESR1 have consistently been shown to be associated with bone mineral density (BMD) and fracture; however, in regulating bone metabolism, ESR1 interacts with both ESR2 and RIZ1. We therefore examined the effects of polymorphisms in the ESR1, ESR2, and RIZ1 genes and their haplotypes on vertebral fractures and BMD in a case-control study comprising 462 osteoporotic patients and 336 controls. In ESR1, we found the variant C allele of the XbaI polymorphism to be associated with decreased risk of vertebral fractures in women (P < 0.01), whereas in men, the T allele seemed protective (P = 0.05). The variant G allele of the PvuII polymorphism decreased the risk of vertebral fractures independently of lumbar spine BMD in women (P = 0.04) but had no effect in men. Haplotype X-P-H (XbaI:C, PvuII:G, and a high number of TA repeats) was associated with decreased risk of vertebral fractures in women (P = 0.04) but not men. In ESR2, the G allele of the AluI polymorphism was associated with increased fracture risk (P = 0.04), and the haplotype that comprises rs1256031:T and AluI:A increased lumbar spine BMD by 0.04 +/- 0.02 g/cm(2) (P < 0.05) and decreased the risk of vertebral fractures (P = 0.04). There was no effect of the RIZ1 polymorphism on BMD or fracture risk and no evidence of interaction between the polymorphisms and haplotypes thereof. We confirm that genetic variants in ESR1 and ESR2, but not RIZ1, are important in osteoporosis. We found no evidence of interaction between polymorphisms, but we found that the effects of genetic variants in ESR1 might be sex dependent.

Effects of two common polymorphisms in the 3' untranslated regions of estrogen receptor beta on mRNA stability and translatability

BACKGROUND

The present study represents the first attempt to functionally characterize two common single nucleotide polymorphisms (SNPs) in the 3'untranslated regions (3'UTRs) of estrogen receptor beta (ERbeta), focusing on the differences between alleles with regard to mRNA stability and translatability. These two ERbeta SNPs have been investigated for association with disease in a large number of reports.

RESULTS

Here we examined allelic expression in breast tumor samples from heterozygous individuals. A significant difference in mRNA levels of the two alleles was observed for one of the SNPs. A cell model system was employed to further investigate potential molecular effects of the two SNPs. We used a modified plasmid, containing the ERbeta promoter and ERbeta 3'UTRs which include the different alleles of investigated SNPs. Quantitative Real-Time PCR was used to determine mRNA levels after inhibition of transcription by actinomycin D, and a luciferase assay was used to determine protein levels. The obtained results suggested that there was no difference in mRNA stability or translatability between the alleles of investigated SNPs.

CONCLUSION

Our results indicate that observed associations between ERbeta 3'UTR SNPs and disease susceptibility are due to linkage disequilibrium with another gene variant, rather than the variant itself being the susceptibility factor.

Lipid profile and inflammatory markers associated with estrogen receptor alpha PvuII and XbaI gene polymorphisms

Estrogen is established to influence lipoprotein metabolism and inflammatory markers. Alternations in estrogen receptor alpha (ESR1) expression and function may affect the role of estrogen in this regard. The aim of this study was to determine whether ESR1 PvuII and XbaI gene polymorphisms have effects on lipoprotein (a) as well as inflammatory variables in an Iranian population. Three hundred and ninety seven consecutive participants (228 men, 57.4%) who were admitted at our center for elective coronary angiography because of symptoms related to coronary artery disease (CAD) were enrolled in our study. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, and triglyceride levels were determined by standard methods using commercial kits. Low-density lipoprotein (LDL)-cholesterol was calculated according to the Friedewald formula. The lipoprotein (a) levels were measured by ELISA method using Biopool kit, and the CRP concentrations were determined by Latex Immunoturbidometry. The presence of PvuII and XbaI polymorphisms within the ESR gene were analyzed using polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP). The frequency of homozygous and heterozygous were 25.9% and 50.1%, for PvuII genotypes, and the frequency was 23.7% and 48.6%, for XbaI genotypes, respectively. After adjusting for CAD and age, no impacts of ESR1 PvuII and XbaI polymorphisms were found on lipid profile, lipoprotein (a) level, and quantitative CRP either in total population or in subgroups stratified by gender. In conclusion, our data demonstrate that ESR1 PvuII and XbaI gene polymorphisms did not seem to have an effect on lipoprotein metabolism or on inflammatory variables such as CRP.

Do Estrogen Receptor beta Polymorphisms Play A Role in the Pharmacogenetics of Estrogen Signaling?

Estrogen hormones play critical roles in the regulation of many tissue functions. The effects of estrogens are primarily mediated by the estrogen receptors (ER) alpha and beta. ERs are ligand-activated transcription factors that regulate a complex array of genomic events that orchestrate cellular growth, differentiation and death. Although many factors contribute to their etiology, estrogens are thought to be the primary agents for the development and/or progression of target tissue malignancies. Many of the current modalities for the treatment of estrogen target tissue malignancies are based on agents with diverse pharmacology that alter or prevent ER functions by acting as estrogen competitors. Although these compounds have been successfully used in clinical settings, the efficacy of treatment shows variability. An increasing body of evidence implicates ERalpha polymorphisms as one of the contributory factors for differential responses to estrogen competitors. This review aims to highlight the recent findings on polymorphisms of the lately identified ERbeta in order to provide a functional perspective with potential pharmacogenomic implications.

ESR1 polymorphism is associated with plasma lipid and apolipoprotein levels in Caucasians of the Rochester Family Heart Study

We evaluated six estrogen receptor 1 (ESR1) polymorphisms for association with ten plasma lipid and apolipoprotein traits in 1,847 individuals (941 females and 906 males) in the multi-generation Rochester Family Heart Study using a generalized estimating equation approach. Apolipoprotein A-I (apoA-I), apoA-II, and HDL-cholesterol (HDL-C) were associated with exon 4 rs1801132 (Pro325Pro) genotype (P = 0.0044, P = 0.0048, and P = 0.0035, respectively). Positive correlation between levels of apoA-I, apoA-II, and HDL-C and the number of G alleles was observed in females (P = 0.0120, P = 0.0032, and P = 0.0030), but not males (P > 0.05). Because few studies have evaluated the effect of ESR1 gene polymorphisms on lipid traits in children, we also stratified our sample at the age of 15 years. There was evidence of association between intron 1 single-nucleotide polymorphisms rs9322331 and rs9340799 and apoC-II, and triglycerides (TGs) in youths 15 years and younger. In youths, evidence of association between rs9322331 and rs9340799 and apoC-II was stronger in males (P = 0.0036 and P = 0.0124) than in females (P > 0.05), whereas evidence of association with TG was stronger in females (P = 0.0030 and P = 0.0024) than in males (P > 0.05). These findings suggest that ESR1 variation plays an age- and sex-dependent role in determining plasma lipid and apolipoprotein levels.

Pharmacogenetics of bone treatments: the VDR and ERalpha gene story

Osteoporosis is a common skeletal disease with a strong genetic component characterized by reduced bone mass and increased risk of fragility fractures. Although osteoporosis is a worldwide problem, there are many differences in human ethnics regarding both disease morbidity and drug treatment efficacy. Polymorphisms of vitamin D receptor (VDR) and estrogen receptor-alpha (ERalpha) loci are proposed as genetic determinants of bone quality, skeletal geometry and bone turnover markers. Furthermore, varying responsiveness to vitamin D and estrogen-based treatments may reflect allele variation in their signaling pathway genes (e.g., VDR or ERalpha). Because of their specific ethnic distribution, VDR and ERalpha polymorphisms may be involved in reported human differences of osteoporosis treatment responses.

Molecular genetic studies of gene identification for osteoporosis

This review comprehensively summarizes the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of September 2007. It is intended to constitute a sequential update of our previously published reviews covering the available data up to the end of 2004. Evidence from candidate gene-association studies, genome-wide linkage and association studies, as well as functional genomic studies (including gene-expression microarray and proteomics) on osteogenesis and osteoporosis, are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. The major results of all studies are tabulated for comparison and ease of reference. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.

Genetics and pharmacogenetics of estrogen response

Estrogens are a steroid hormone group distributed widely in animals and human beings. Estrogens diffuse across cell phospholipidic membranes and interact with estrogen receptors. Their highest concentration is found in target tissues with reproductive function (breast, ovary, vagina and uterus). High estrogen levels are usually associated with tumor onset and progression, while loss of estrogen or its receptor(s) contributes to development and/or progression of various diseases (osteoporosis, neurodegenerative disease and cardiovascular disease). Despite the numerous efforts to highlight estrogen's mechanism of action, recent discoveries showed an unexpected degree of complexity of estrogenic response.

Steroid hormone receptor gene polymorphisms and osteoporosis: a pharmacogenomic review

Osteoporosis is a common skeletal disorder with a strong genetic component. In recent years, significant progress has been made in understanding the genetic basis of osteoporosis. Given the biological significance of signalling through steroid hormone receptors, bone biology and calcium homeostasis, alleles of steroid hormone receptor genes have been postulated to contribute to the well-documented genetic predisposition to osteoporosis; and in different studies, these alleles have been associated with variation in bone mass and fracture risk. Even though results are still conflicting and the molecular mechanisms by which these polymorphisms influence receptor activity remain, in part, to be investigated, an additional important issue is represented by potential pharmacogenomic (the investigation of variations of DNA or RNA characteristics as related to drug response) or pharmacogenetic (the influence of variations of DNA sequence on drug response) implications. In fact, steroid hormone receptors actually mediate the action of several compounds known to positively or negatively affect bone homeostasis, such as vitamin D, estrogen and glucocorticoids. This review analyses major pharmacogenetic studies of polymorphisms in steroid hormone receptor genes.

Lipid, haemostatic and inflammatory variables in relation to the estrogen receptor alpha (ESR1) PvuII and XbaI gene polymorphisms

BACKGROUND

Estrogen is known to affect lipoprotein metabolism, the haemostatic system and inflammatory markers. Our aim was to determine whether estrogen receptor alpha (ESR1) PvuII and XbaI gene polymorphisms can influence lipid, haemostatic and inflammatory variables in healthy Caucasian women and men of reproductive age.

METHODS

58 healthy women (aged between 18 and 45 years) and 55 healthy men (aged between 21 and 45 years) of reproductive age were enrolled in our study. FSH levels, lipid (total cholesterol, triglyceride, HDL cholesterol, lipoprotein(a), apo A-I, apo B), haemostatic (prothrombin time, activated partial thromboplastin time (aPTT), thrombin time, fibrinogen, factor V, VII, VIII, protein C, protein S, antithrombin III) and inflammatory (CRP) variables were measured on autoanalyzers using commercially available kits. Serum VLDL and LDL cholesterol concentrations were calculated with the equation of Friedewald. The ESR1 PvuII and XbaI genotypes were determined with PCR-RFLP method.

RESULTS

In the total group, the ESR1 XbaI GG genotype carriers had significantly higher serum lipoprotein(a) concentrations than the AA or AG genotype carriers. Serum total cholesterol concentrations were significantly higher in healthy women with the PvuII CC genotype than in those with the TT or TC genotypes, whereas healthy women with the GG genotype of the ESR1 XbaI polymorphism had significantly higher serum total cholesterol and LDL cholesterol levels compared to those with the AA or AG genotypes. No other effects of the ESR1 PvuII and XbaI polymorphisms were found on the investigated lipid, haemostatic and inflammatory variables either in the total group or in women and men separately.

CONCLUSIONS

The ESR1 PvuII and XbaI gene polymorphisms seem to affect lipoprotein metabolism in healthy subjects of peak reproductive age. However, further studies are needed to determine the molecular mechanisms by which the two polymorphisms could influence serum lipid levels.