China
Africa
Explore chapters and articles related to this topic
Tocotrienol Vitamin E and Neurodegenerative Disorders
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
PD is a neurodegenerative disease of the central nervous system resulting from the loss of the dopaminergic neurons. Oxidative stress and increased dopamine oxidation plays an important role in the etiology and development of PD [61]. In this diseases, natural vitamins E forms have shown protective effects against neuronal cell death (Table 14.1). In recent research, it has been reported that oral administration of δ-tocotrienol vitamin E is a suitable agent in the treatment of PD (Figure 14.3). Estrogen receptor-β (ERβ) is a candidate target for the neuroprotection activity of δ-tocotrienol. ERβ-mediated neuroprotective effects of δ-tocotrienol in PD were investigated in in-vivo mice model. ERβ was expressed in neuronal cells with dopaminergic neurons. Oral supplementation of δ-tocotrienol inhibited the loss of dopaminergic neurons. Furthermore, δ-tocotrienol administration enhanced the performance of the PD mice model in the wheel running activity [11].
Current and emerging pharmacological agents in the treatment of osteoporosis
Published in Peter V. Giannoudis, Thomas A. Einhorn, Surgical and Medical Treatment of Osteoporosis, 2020
James X. Liu, Thomas A. Einhorn
Raloxifene exerts its action as either an estrogen agonist or antagonist depending on the specific tissue that it targets. There are two primary isoforms of estrogen receptors: estrogen receptor alpha (ERα), which is primarily an activating receptor, and estrogen receptor beta (ERβ), which is primarily an inhibiting receptor (6). ERβ exerts its inhibitory action on ERα by forming a heterodimer. Thus, the levels of expression that are unique to a particular tissue type have different levels of isoforms that will direct cellular responsiveness to estrogens. In general, raloxifene functions as an estrogen agonist in bone and lipid metabolism and functions as an estrogen antagonist in breast and uterine tissue.
The Role of Epigenetics in Breast Cancer: Implications for Diagnosis, Prognosis, and Treatment
Published in Brian Leyland-Jones, Pharmacogenetics of Breast Cancer, 2020
Amy M. Dworkin, Tim H.-M. Huang, Amanda E. Toland
Along with other genes, the estrogen receptors (ERs) ERα and ERβ have been implicated in breast cancer development. ERβ is encoded by ESR1, and when estrogen is activated, it stimulates cell proliferation. ERβ is encoded by ESR2 and is known to inhibit the proliferation and invasion of breast cancer cells. ERα and ERβ both have promoter-associated CpG islands that can be abnormally methylated in breast cancer, but ESR2 methylation has been less well studied (16,18). Almost all breast cancers show some degree of DNA methylation of the ESR1 gene promoter, but this methylation is only associated with gene repression in ˜30% of tumors (16,18). Approximately 66% of breast cancers express ERα. A fraction of breast cancers that are initially ERα positive lose ER expression during tumor progression, but it is unclear if this is due to methylation or other causes (18).
Impacts of menopause hormone therapy on mood disorders among postmenopausal women
Published in Climacteric, 2022
P. Feng, L. Lin, Y. Wang, L. Chen, J. Min, Y. Xie, M. Liu, S. Wei, S. Lin, Q. Yu
MHT is a critical medical intervention in the health management of postmenopausal women. Emotional disorders tend to occur during the period of sex hormone fluctuations. However, there are also different points of view that menopause will not directly lead to emotional problems and that neurotransmitters cause emotional disorders [3]. Existed studies have been mainly devoted to exploring the emotional disorders during menopausal transition or early menopausal stages and the role of MHT in improving emotional disorders. At present, most studies have confirmed that MHT could improve mood disorders in the perimenopausal period [11,14]. Amygdala, hippocampal and several non-mesial temporal structures are the central areas involved in emotional regulation [3]. Estrogen therapy could protect the aforementioned structural changes during menopausal and postmenopausal periods and improve depression [41]. Estrogen receptor (ER) subtypes mainly consist of ERα and ERβ. Different subtypes of receptors have various actions on anxiety. ERα has an anxiety effect, while ERβ has a universal antianxiety impact [2,42]. We also found that long-term use of MHT could improve the emotional problems of postmenopausal women. For depression, there was a significant difference in CES-D scores between the two groups. In terms of anxiety status, no significant difference between the two groups was detected. Plasma estrogen levels were reported to be significantly lower in depressed women, suggesting that low estrogen could potentially lead to mood disorders or related symptoms [43].
Novel daidzein molecules exhibited anti-prostate cancer activity through nuclear receptor ERβ modulation, in vitro and in vivo studies
Published in Journal of Chemotherapy, 2021
R. Ranjithkumar, K. Saravanan, B. Balaji, S. Hima, S. Sreeja, S. R. Timane, M. Ram Pravin Kumar, S. Kabilan, M. Ramanathan
Estrogen receptor β (ERβ) is involved in the differentiation of prostatic epithelial cells and numerous antiproliferative actions on prostate cancer cells. ERβ splice variants have been associated with prostate cancer (PCa) initiation and progression mechanisms. ERβ targeting is promising as an anticancer therapy and in the prevention of prostate cancer. The role of ERβ in PCa initiation has been supported by studies using the ER-knockout (ERKO) mice. ERα-knockout mice do not develop prostate cancer after testosterone and/or estrogen treatment, whereas mice lacking ERβ receptor develop prostate cancer after the addition of sex hormones, similarly to wild-type mice. This antiproliferative role of ERβ also concurs with immunohistochemical findings in human PCa tissue samples, suggesting that ERβ expression is lost in tumours. The promise of ERβ activation, as a potential targeted therapy, is based on concurrent activation of multiple tumour suppressor pathways with few side effects compared to chemotherapy. Thus, ERβ is a nuclear receptor with broad-spectrum tumour suppressor activity, which could serve as a potential treatment target in a variety of human cancers including prostate cancer and breast cancer.38,44
Interactions between estradiol, diabetes, and brain aging and the risk for cognitive impairment
Published in Climacteric, 2021
C. E. Hugenschmidt, T. Duran, M. A. Espeland
The two primary estrogen receptors (ERs), ERα and ERβ, appear to have distinct and complementary roles in regulating the metabolic effects of estrogen40,46. The effects of signaling through ERα and ERβ are nuanced, and may differ based on the tissue type and cellular compartment40,46. However, generally speaking, signaling through ERα appears to have overall anti-diabetic effects, including increasing insulin sensitivity in multiple tissues and improving the lipid profile41,46. ERβ signaling is not as well understood, but can have both pro-diabetic and anti-diabetic effects, depending on the tissue type, cellular compartment, and receptor subtype40. The balance of ER subtypes changes with age, which results in an overall decrease in ERα expression and an increasing number of splice variants for ERβ47. The consequences of these alterations in ER type and distribution are not yet fully understood40,47. However, postmenopausal alterations in ER variants and distribution are hypothesized as a factor to explain the effects of timing in response to estrogen48.