Aging of Brain: Role of Estrogen

Role of nutraceuticals in cognition during aging and related disorders

Cognitive abilities are compromised with advancing age posing a great risk for the development of dementia and other related brain disorders. Genetic susceptibility as well as environmental exposures determine the fate of cognitive aging and its transition to pathological states. Emerging epidemiological and observational studies have revealed the importance of lifestyle factors including dietary patterns and nutritional intake in the maintenance of cognitive health and reducing the risk of neurodegenerative disorders. In this context, nutraceutical interventions have gained considerable attention in preventing age-related cognitive deficits and counteracting pathological processes. Nutraceuticals include dietary plants and derivatives, food supplements and processed foods with nutritional and pharmaceutical values. The present review highlights the importance of nutraceuticals in attenuating cognitive aging and its progression to dementia, with specific emphasis on chemical constituents, neurocognitive properties and mechanism of action.

The effect of n-3 long-chain polyunsaturated fatty acids and lipoic acid on the heart in the ovariectomized rat model of menopause

Menopause occurs as consequence of ovarian senescence that leads to a drop of oestrogen hormone. The decreased oestrogen levels combined with the impairment of the redox system may contribute to the increased risk of postmenopausal cardiovascular disease. Supplementation with antioxidants may be an alternative to reduce cardiovascular risk. The study evaluated the effect of dietary supplementation with docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and α-lipoic acid (LA) for a period of 16 weeks on oxidative stress biomarkers in the hearts of ovariectomized 3-month-old rats. Ovariectomy did not increase the level of the damage markers malondialdehyde and carbonyl, and both were decreased by LA supplementation. Ovariectomy increased the levels of the endogenous antioxidants glutathione, vitamin C and H₂O₂ consumption, after restoration by DHA, EPA, and LA supplementation. Vitamin E, glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase are not altered by ovariectomy. Lipid and protein damage are not increased after ovariectomy and a portion of the endogenous antioxidants concomitantly increased, suggesting that hearts may be protected by these antioxidants. DHA, EPA, and LA restored these endogenous antioxidants, showing that all evaluated supplements are effective in modulating the antioxidant redox system in the heart. LA showed additional effect on redox markers, decreasing lipid and protein damage markers.

Complexity Changes in Brain Activity in Healthy Ageing: A Permutation Lempel-Ziv Complexity Study of Magnetoencephalograms

Maturation and ageing, which can be characterised by the dynamic changes in brain morphology, can have an impact on the physiology of the brain. As such, it is possible that these changes can have an impact on the magnetic activity of the brain recorded using magnetoencephalography. In this study changes in the resting state brain (magnetic) activity due to healthy ageing were investigated by estimating the complexity of magnetoencephalogram (MEG) signals. The main aim of this study was to identify if the complexity of background MEG signals changed significantly across the human lifespan for both males and females. A sample of 177 healthy participants (79 males and 98 females aged between 21 and 80 and grouped into 3 categories i.e., early-, mid- and late-adulthood) was used in this investigation. This investigation also extended to evaluating if complexity values remained relatively stable during the 5 min recording. Complexity was estimated using permutation Lempel-Ziv complexity, a recently introduced complexity metric, with a motif length of 5 and a lag of 1. Effects of age and gender were investigated in the MEG channels over 5 brain regions, i.e., anterior, central, left lateral, posterior, and, right lateral, with highest complexity values observed in the signals recorded by the channels over the anterior and central regions of the brain. Results showed that while changes due to age had a significant effect on the complexity of the MEG signals recorded over 5 brain regions, gender did not have a significant effect on complexity values in all age groups investigated. Moreover, although some changes in complexity were observed between the different minutes of recording, due to the small magnitude of the changes it was concluded that practical significance might outweigh statistical significance in this instance. The results from this study can contribute to form a fingerprint of the characteristics of healthy ageing in MEGs that could be useful when investigating changes to the resting state activity due to pathology.

Age-associated Cognitive Decline: Insights into Molecular Switches and Recovery Avenues

Age-associated cognitive decline is an inevitable phenomenon that predisposes individuals for neurological and psychiatric disorders eventually affecting the quality of life. Scientists have endeavored to identify the key molecular switches that drive cognitive decline with advancing age. These newly identified molecules are then targeted as recovery of cognitive aging and related disorders. Cognitive decline during aging is multi-factorial and amongst several factors influencing this trajectory, gene expression changes are pivotal. Identifying these genes would elucidate the neurobiological underpinnings as well as offer clues that make certain individuals resilient to withstand the inevitable age-related deteriorations. Our laboratory has focused on this aspect and investigated a wide spectrum of genes involved in crucial brain functions that attribute to senescence induced cognitive deficits. We have recently identified master switches in the epigenome regulating gene expression alteration during brain aging. Interestingly, these factors when manipulated by chemical or genetic strategies successfully reverse the age-related cognitive impairments. In the present article, we review findings from our laboratory and others combined with supporting literary evidences on molecular switches of brain aging and their potential as recovery targets.

Analysis of Interaction of Estradiol with Estrogen Receptor by NMR Spectroscopy

Following binding to estradiol, estrogen receptors (ER) α and ERβ recruit a number of interacting proteins and mediate a plethora of functions. The binding of estrogen with the receptors shows changes in the resonance structure and movement of protons. We cloned ERβ and its trans-activation domain (TAD) and ligand-binding domain (LBD), expressed them in prokaryotic expression vectors, purified them, and studied their interaction with estradiol. In this chapter, a detailed method of preparation of recombinant proteins, SDS-PAGE, silver staining, and NMR are described. Such methods are useful to check the biological activity of bacterially expressed proteins and are applicable to basic and applied research.

Analysis of estrogen receptor β interacting proteins using pull-down assay and MALDI-MS methods

Estrogen mediates a plethora of functions through well-characterized estrogen receptor (ER)α and ERβ after recruiting a number of interacting proteins. Various laboratories including ours have focused on the identification of ERβ interacting proteins using different methods including matrix-assisted laser desorptive ionization (MALDI), which is a powerful technique in proteomics to identify new proteins present in low abundance. We have identified ERβ interacting proteins resolved by one-dimensional preparatory sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and two-dimensional SDS-PAGE followed by MALDI-MS. In this chapter, a detailed method of pull-down assay, SDS-PAGE, MALDI-MS, and immunoblotting along with the use of software for identification of interacting proteins have been described. Such methods are useful to identify the interacting proteins, which may predict the function and molecular mechanism of action that is helpful for developing therapeutic strategies.

Oestrogen receptor α agonist improved long-term ovariectomy-induced spatial cognition deficit in young rats

Ovariectomy is known as 'surgical menopause' with decreased levels of oestrogen in female rodents and its reported risks and adverse effects include cognitive impairment. In the brain, oestrogen exerts effects through its receptors, oestrogen receptor α (ERα) and β (ERβ). However, the role of ERα or ERβ in ovariectomy-induced cognitive impairment needs further investigation. Here, we observed that bilaterally ovariectomized 3-month-old rats showed obvious spatial learning and memory deficits in the Morris water maze with significant loss of neurons and synapses in the hippocampus. In addition to the rapid decline in serum oestradiol levels, the expression of ERα, but not ERβ, was decreased in the hippocampus starting 1 wk after ovariectomy. Prompt 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT) treatment (1 mg/kg.d), an agonist of ERα, improved the spatial learning and memory ability of ovariectomized rats and rescued ovariectomy-induced neuron loss by up-regulating the level of BCLxl, an important anti-apoptosis protein. Furthermore, PPT treatment also improved ovariectomy-induced hippocampal synapse loss and up-regulated the levels of synaptic proteins (synapsin I, NR2A and GluR1) and the activates of CaMK Πα, ERK and Akt. Thus, these results demonstrated that ERα plays an important role in neuroprotection and that prompt ERα rescue is effective to improve hippocampal-dependent cognition deficit after long-term ovariectomy.

Opening up the window into "chemobrain": a neuroimaging review

As more chemotherapy-treated cancer patients are reaching survivorship, side-effects such as cognitive impairment warrant research attention. The advent of neuroimaging has helped uncover a neural basis for these deficits. This paper offers a review of neuroimaging investigations in chemotherapy-treated adult cancer patients, discussing the benefits and limitations of each technique and study design. Additionally, despite the assumption given by the chemobrain label that chemotherapy is the only causative agent of these deficits, other factors will be considered. Suggestions are made on how to more comprehensively study these cognitive changes using imaging techniques, thereby promoting generalizability of the results to clinical applications. Continued investigations may yield better long-term quality of life outcomes by supporting patients' self-reports, and revealing brain regions being affected by chemotherapy.

Changes in oestrogen receptor-β mRNA expression in male rat brain with age

Oestrogen has important roles not only in the regulation of reproductive function, but also with respect to other functions, such as cognition, emotion and cardiovascular regulation. Oestrogen acts mainly via its oestrogen receptor (ER), namely, ERα and ERβ in target tissues, including the brain. During ageing, the actions of oestrogen are altered in both females and males, raising the possibility that the expression level of ER may be altered with age. Age-related changes in ER expression in female rat brain have been well demonstrated with regard to reproductive ageing, whereas very little is known about the effects of age on the expression of ERs, especially ERβ, in males. In the present study, which aimed to elucidate the effects of ageing on ERβ expression in the male brain at the transcriptional level, we performed in situ hybridisation using young (10weeks), middle-aged (12months) and old (24 months) gonadally-intact male rats. We revealed a wide distribution of ERβ mRNA-positive cells throughout the brain, and found that the number of ERβ mRNA-positive cells was reduced in several brain regions in males with ageing. ERβ mRNA-positive cells were decreased with age in layer 6 of the cerebral cortex, hippocampal CA1/CA3 regions, the dorsal endopiriform nucleus, the medial septal nucleus, various subregions of the amygdala (central, lateral, anterior cortical and posterolateral cortical subnuclei), the anteroventral periventricular nucleus, the substantia nigra pars compacta, the raphe magnus nucleus and the locus coeruleus. These results suggest that ERβ expression in male rat brain decreases with age at the transcriptional level and that these ageing effects are region-specific.

17-β estradiol in the acetylcholinesterase activity and lipid peroxidation in the brain and blood of ovariectomized adult and middle-aged rats

AIMS

To investigate the 17-β estradiol in the acetylcholinesterase activity and lipid peroxidation in the brain and blood of ovariectomized rats of different ages.

MAIN METHODS

Animals were randomly assigned into three experimental groups of each age (n=6). Control groups consisted of adult (sham-A) and middle-aged (sham-MA) female rats, ovariectomized adult (OVX-A) and middle-aged (OVX-MA) rats without estrogen therapy reposition, and ovariectomized adult (OVX+E2-A) and middle-aged (OVX+E2-MA) rats treated with 17-β estradiol for 30days. After this period, AChE activity and lipid peroxidation were measured in the brain and blood.

KEY FINDINGS

The AChE activity increased (p<0.05) in striatum (ST) in OVX-A, OVX+E2-A and OVX-MA, and hippocampus (HP) in OVX-MA. The enzyme activity decreased (p<0.05) in ST of OVX+E2-MA, and cerebral cortex (CC) in OVX+E2-A, OVX-MA and OVX+E2-MA. Blood AChE activity increased (p<0.05) in OVX+E2-A and decreased (p<0.05) in OVX-MA. Lymphocyte AChE activity increased (p<0.05) in OVX-A and OVX+E2-A and decreased (p<0.05) in OVX-MA. Lipid peroxidation increased (p<0.05) in ST of OVX-A, CC of OVX-A and OVX-MA, HP of OVX-A, and cerebellum (CE) of OVX-A, OVX-MA, and OVX+E2-MA. Lipid peroxidation decreased (p<0.05) in ST, CC and CE of OVX+E2-A, and ST and HP of OVX+E2-MA. Similar values of lipid peroxidation to control groups were found in ST and HP of OVX-MA, HP of OVX+E2-A and CC of OVX+E2-MA.

SIGNIFICANCE

17-β estradiol is able to modulate the AChE activity and non-neuronal cholinergic response as well as to reduce lipid peroxidation. Its response is dependent on the age and brain structure analyzed.

Soy content of basal diets determines the effects of supplemental selenium in male mice

The effects of supplemental Se in rodent models may depend upon composition of the basal diet to which it is added. Wild-type male littermates of Transgenic Adenocarcinoma of Mouse Prostate mice were fed until 18 wk of age 1 of 2 Se-adequate stock diets high in soy (HS) or low in phytoestrogens (LP) or the same diets supplemented with 3.0 mg Se/kg diet as seleno-methylselenocysteine. Body and abdominal fat pad weights were lower (P < 0.01) in mice fed the HS diet. Supplemental Se reduced fat pad weights in mice receiving the LP diet but increased body and fat pad weights in mice consuming the HS formulation (P-interaction < 0.005). Serum free triiodothyronine concentrations were unaffected by supplemental Se in mice fed the LP diet but were decreased by Se supplementation of mice given the HS feed (P-interaction < 0.02). Free thyroxine concentrations were higher in mice consuming the HS diet regardless of Se intake (P < 0.001). Hepatic mRNA for iodothyronine deiodinase I was lower (P < 0.001) in mice fed the HS diet. Supplementation of Se increased this mRNA (P < 0.001) in both diet groups. Results from this study show a significant interaction between the composition of basal diets and the effects of supplemental Se with respect to body composition. These findings have important implications for future studies in rodent models of the effects of supplemental Se on heart disease, cancer, diabetes, and other conditions related to body weight and composition.

Effect of soybean supplementation on the memory of alprazolam-induced amnesic mice

Soybean, Glycine max (L.) Merr. (Leguminoseae), is known as golden bean. It contains vegetable protein, oligosaccharide, dietary fiber, vitamins, isoflavones and minerals. Earlier studies have demonstrated a cholesterol lowering, skin protective, antitumour, antidiabetic and antioxidative potential of soybean. Soy isoflavones are also utilized as estrogen replacement therapy in postmenopausal women. The present study was undertaken to investigate the effect of soybean on memory of mice when consumed along with diet. Soybean was administered chronically for 60 consecutive days as three soybean diets viz. Soy2, Soy5, Soy10. These diet contains soybean in normal diet at concentration of 2%, 5%, 10% w/w respectively. Passive avoidance paradigm and elevated plus maze served as exteroceptive behavioral models for testing memory. Alprazolam (0.5 mg/kg; i.p.) induced amnesia served as interoceptive behavioral model. The administration of soybean significantly reversed alprazolam-induced amnesia in a dose-dependent manner as indicated by the increased step down latency of mice using passive avoidance paradigm and increased transfer latency using elevated plus maze. Theses results suggest that consumption of soybean in diet may not only improve memory but also reverse the memory deficits, owing to its multifarious activities. It would be worthwhile to explore the potential of this nutrient in the management of Alzheimer's disease.

Expression of Trk A and Src and their interaction with ERβ ligand binding domain show age and sex dependent alteration in mouse brain

Following the binding of estrogen to estrogen receptor (ER)β ligand binding domain (LBD) and its interaction with the target genes, a host of nuclear proteins is recruited to regulate the expression of specific genes(s). It is not known which proteins interact with ERβLBD and whether they vary with age and sex in the brain. Therefore, using pull down assay, immunoprecipitation and immunoblotting, we report that cell signaling molecules Trk A and Src interacted with ERβLBD, and showed alteration in the level of interaction and expression in the brain of AKR strain young (6 weeks), adult (25 weeks) and old (70 weeks) mice of both sexes. Trk A showed decreasing interaction with age, and lower expression in adult as compared to young and old males, whereas female mice exhibited decline in both interaction and expression as a function of age. On the other hand, Src interaction with ERβLBD decreased, but its expression increased with age in males, whereas the interaction and expression was lower in adult but higher in old as compared to young females. These findings suggest the implication of Trk A and Src in ERβ mediated brain functions and related disorders during aging.

Postmenopausal hormone use impact on emotion processing circuitry

Despite considerable evidence for potential effects of estrogen on emotional processing, several studies of postmenopausal women who began hormone therapy (HT) remote from menopause report no effects of HT on emotional measures. As early HT initiation may preserve brain mechanisms, we examined effects of HT on emotional processing in postmenopausal women who started HT early after menopause. We performed a cross-sectional comparison of 52 postmenopausal women 66±5 years old, including 15 users of conjugated equine estrogen, 20 users of conjugated equine estrogen plus medroxyprogesterone acetate, and 17 who never used hormones (NT). All hormone users started therapy within two years of menopause, and received at least 10 years of continuous therapy. Outcomes were fMRI-detected brain activity and behavioral measures during an emotional processing picture rating task. During processing of positive pictures, NT women had greater activation than estrogen treated women in medial prefrontal cortex extending to the anterior cingulate, and more activation than estrogen plus progestin treated women in the insula. During processing of negative pictures, estrogen treated women had higher activation than NT women in the entorhinal cortex. Current compared to past HT users showed greater activation in the hippocampus and higher emotion recognition accuracy of neutral stimuli. Estrogen plus progestin treated women had slower response time than NT women when rating all pictures. In conclusion, hormone use was associated with differences in brain functional responses during emotional processing. These fMRI effects were more prominent than those observed for behavioral measures and involved brain regions implicated in cognitive-emotional integration.

Soybean supplementation helps reverse age- and scopolamine-induced memory deficits in mice

Phytoestrogens are nonsteroidal plant compounds that are able to exert estrogenic effects. Soybean is a rich source of phytoestrogens, especially isoflavones. Soy isoflavones are utilized for estrogen replacement therapy. Estrogen is reported to influence several areas of brain that are involved in cognition and behavior. Therefore, the present study was undertaken to examine whether dietary supplementation with soybean improves the cognitive function of mice. Soybean was administered in three different concentrations (2%, 5% and 10% [wt/wt]) in the normal diet to young and mature mice for 60 successive days. The passive avoidance paradigm and the elevated plus maze served as the exteroceptive behavioral models, whereas scopolamine (1.4 mg/kg, i.p.) served as the interoceptive behavioral model. The brain acetylcholinesterase activity (AChE) activity, brain thiobarbituric acid-reactive substances (TBARS), reduced glutathione (GSH), and total blood cholesterol levels were also measured in the present study. The administration of soybean for 60 consecutive days protected (P < .05) the animals from developing memory impairment. Soybean administration also resulted in diminished brain AChE activity, decrease in brain TBARS, and increase in GSH levels, thereby indicating facilitated cholinergic transmission, reduced free radical generation, and enhanced scavenging of free radicals. Thus, soybean appears to be a useful remedy for improving memory and for the management of cognitive deficits owing to its pro-estrogenic, antioxidant, procholinergic, and/or neuroprotective properties.

Interaction of Estrogen Receptor Associated Protein (ERAP) 140 with ER beta decreases but its expression increases in aging mouse cerebral cortex

Following binding to cognate ligand, estrogen receptor (ER) beta interacts with specific responsive elements of the target genes and recruits a host of nuclear proteins for hormone dependent gene regulation. However, it is poorly known which proteins interact with ER beta in mouse brain and whether their interaction and expression change with age. In this report, we have used his-tag mouse ER beta for interaction with nuclear proteins of cerebral cortex of young (6 +/- 1 weeks), adult (25 +/- 2 weeks), and old (70 +/- 5 weeks) female mice. We have identified estrogen receptor-associated protein (ERAP) 140 as one of the interacting proteins and studied its interaction by pull down immunoblotting, far-Western blotting and immunoprecipitation, and expression by western blotting. The data show that ERAP 140 interacts with ER beta and its interaction decreases but its expression increases with age in mouse cerebral cortex, suggesting its role in estrogen-mediated brain functions during aging.

Estradiol and the relationship between dendritic spines, NR2B containing NMDA receptors, and the magnitude of long-term potentiation at hippocampal CA3-CA1 synapses

When circulating estrogen levels decline as a natural consequence of menopause and aging in women, there is an increased incidence of deficits in working memory. In many cases, these deficits are rescued by estrogen replacement therapy. These clinical data therefore highlight the importance of defining the biological pathways linking estrogen to the cellular substrates of learning and memory. It has been known for nearly two decades that estrogen enhances dendritic spine density on apical dendrites of CA1 pyramidal cells in hippocampus, a brain region required for learning. Interestingly, at synapses between CA3-CA1 pyramidal cells, estrogen has also been shown to enhance synaptic NMDA receptor current and the magnitude of long-term potentiation, a cellular correlate of learning and memory. Given that synapse density, NMDAR function, and long-term potentiation at CA3-CA1 synapses in hippocampus are associated with normal learning, it is likely that modulation of these parameters by estrogen facilitates the improvement in learning observed in rats, primates and humans following estrogen replacement. To facilitate the design of clinical strategies to potentially prevent or reverse the age-related decline in learning and memory during menopause, the relationship between the estrogen-induced morphological and functional changes in hippocampus must be defined and the role these changes play in facilitating learning must be elucidated. The aim of this report is to provide a summary of the proposed mechanisms by which this hormone increases synaptic function and in doing so, it briefly addresses potential mechanisms contributing to the estrogen-induced increase in synaptic morphology and plasticity, as well as important future directions.

Interaction of estrogen receptor-alpha ligand binding domain with nuclear proteins of aging mouse brain

After the interaction of estrogen with the ligand binding domain (LBD) of mouse estrogen receptor-alpha (mERalpha) and hormone-responsive elements of target genes, many nuclear proteins are recruited to regulate the expression of specific genes. Because it is not known which brain proteins interact with LBD or whether these proteins vary with age and sex, we used pull-down assay and far Western blotting to detect five nuclear proteins of 160, 140, 87, 60, and 46 kD in the mouse brain. These interacting proteins were identified as PELP1, RIP140, PGC1alpha, BAF60, and ADA3, respectively. The level of PELP1, RIP140, PGC1alpha, and BAF60 decreased drastically in old compared with adult male mice, whereas the ADA3 level showed no significant change. PELP1, PGC1alpha, and BAF60 levels were lower in old male compared with female mice. Thus we report the identification and interaction of five nuclear proteins with mERalpha-LBD, indicating their role in estrogen signaling and brain functions during aging.

Interaction of estrogen receptor-alpha transactivation domain with nuclear proteins of mouse brain: p68 RNA helicase shows age- and sex-specific change

Estrogen receptor (ER)-alpha interacts with nuclear proteins to mediate its multiple functions in the brain. However, it is not known which proteins interact with the ERalpha-transactivation domain (TAD) in mouse brain and whether they change with age and sex. Therefore, we have used affinity-purified GST-tagged mouse ERalpha-TAD fusion protein for interaction with nuclear proteins from the mouse brain. The pull-down assay and far-Western blotting detected four nuclear proteins of 100, 80, 68, and 50 kD. We have recently identified the 80-kD protein as MTA1 and demonstrated its decrease in old age. Here we report alteration in the interaction and expression of the 68-kD protein of adult and old mice of both sexes. This protein was identified as p68 RNA helicase through NCBI database search, immunoprecipitation, and immunoblotting. Further analysis showed that the extent of its interaction was relatively lower in old mice of both sexes and in male mice of both ages compared with their counterparts. However, the expression of p68 was significantly lower in old males compared with adult males, although other groups did not show significant changes. Such age- and sex-specific interaction of p68 suggests its implication in ERalpha-mediated brain functions during aging.

PS2 protein expression is upregulated by sex steroids in the cerebral cortex of aging mice

Mutations in presenilin (PS) genes cause majority of early onset Alzheimer's disease (AD), an age related neurodegenerative disorder. PS proteins undergo proteolytic cleavage to produce biologically active fragments, which constitute the catalytic core of the gamma-secretase enzyme. This enzyme cleaves beta-amyloid precursor protein (betaAPP) to generate Abeta peptides, which are influenced by sex steroids. Recently we have reported the downregulation of PS1 expression by sex steroids in the brain of adult mice. Here we have examined the effect of gonadectomy and subsequent administration of gonadal hormones 17beta-estradiol and testosterone on the level of PS2 C-terminal fragment (CTF) in the cerebral cortex of adult and old AKR strain mice of both sexes. PS2 expression was downregulated following gonadectomy, but upregulated by supplementation of gonadal steroids in both age groups and sexes. Thus these results demonstrate up-regulation of PS2 protein expression by sex steroids, which in turn may influence PS2 associated brain functions.

The interactions between GPR30 and the major biomarkers in infiltrating ductal carcinoma of the breast in an Asian population

OBJECTIVE

G-protein-coupled receptor 30 (GPR30) has been reported to be a novel estrogen receptor alpha (ERalpha) in vitro. Therefore, the interactions among GPR30, ERalpha, progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2/neu), and their prognostic utilities in the infiltrating ductal carcinoma (IDC) of the breast were evaluated.

MATERIALS AND METHODS

Messenger RNA (mRNA) levels of GPR30, ERalpha, PR and HER-2/neu in the tumor samples of 118 Taiwanese IDC patients and 27 non-tumor mammary tissues were measured via quantitative polymerase chain reaction analyses. The correlations of GPR30 mRNA levels with clinical parameters, i.e. tumor/non-tumor, ERalpha, PR, HER-2/neu, age, lymph node metastasis, lymph-vascular invasion, grade, stage and patient survival, were assessed by using appropriate statistical analyses.

RESULTS

GPR30 expression was observed to be lower in IDC (p < 0.001) than in non-tumor mammary tissues. Importantly, GPR30 mRNA level was positively correlated with that of ERalpha (p = 0.001) and PR (p = 0.001) but not correlated with that of HER-2/neu when they were analyzed as continuous variables. However, lower GPR30 was noticed in tumors with HER-2/neu protein overexpression. GPR30 expression was not correlated with age, lymph node metastasis, lymph-vascular invasion, grade and stage in IDC. GPR30 expression was not an independent prognostic factor for patient survival.

CONCLUSION

GPR30 expression is downregulated in IDC. GPR30 is preferentially co-expressed with ER and/or PR but is lowly expressed in HER-2/neu(+) tumors. The correlation of GPR30 expression with clinical parameters, including patient survival, was not evident in this cohort.

Age-related changes in the expression of ER-beta mRNA in the female rat brain

Estrogen is important for numerous physiological actions, most of which are mediated via the nuclear estrogen receptors (ERs), ER-alpha and ER-beta, which modulate the transcription of target genes following estrogen binding. Estrogen functions change with age. In the present study, to reveal the effects of normal aging on ER-beta expression in the brain, we examined ER-beta expression at the transcriptional level using young (10 weeks), middle-aged (12 months) and old (24 months) intact female rats. In situ hybridization using a digoxigenin-labeled RNA probe was used to assess the number of ER-beta mRNA-positive cells in each region in whole brain. ER-beta mRNA-positive cells were detected throughout the brain in young female rats and were reduced in number in the olfactory bulb, cerebral cortex, hippocampus, accumbens nucleus, part of the amygdala and raphe nucleus of middle-aged rats but did not decline further in number in aged animals. By contrast, the number of ER-beta mRNA-positive cells in the hippocampus, caudate putamen, claustrum, accumbens nucleus, substantia nigra and cerebellum was not significantly different between young and middle-aged rats but was decreased in old rats. These results indicate that the expression of ER-beta mRNA in the female rat brain is differentially modulated during aging and that the changes are region specific.