G protein-coupled estrogen receptor 1 ameliorates nonalcoholic steatohepatitis through targeting AMPK-dependent signaling

Nonalcoholic fatty liver disease (NAFLD), especially nonalcoholic steatohepatitis (NASH), has emerged as a prevalent cause of liver cirrhosis and hepatocellular carcinoma, posing severe public health challenges worldwide. The incidence of NASH is highly correlated with an increased prevalence of obesity, insulin resistance, diabetes, and other metabolic diseases. Currently, no approved drugs specifically targeted for the therapies of NASH partially due to the unclear pathophysiological mechanisms. G protein-coupled estrogen receptor 1 (GPER1) is a membrane estrogen receptor involved in the development of metabolic diseases such as obesity and diabetes. However, the function of GPER1 in NAFLD/NASH progression remains unknown. Here, we show that GPER1 exerts a beneficial role in insulin resistance, hepatic lipid accumulation, oxidative stress, or inflammation in vivo and in vitro. In particular, we observed that the lipid accumulation, inflammatory response, fibrosis, or insulin resistance in mouse NAFLD/NASH models were exacerbated by hepatocyte-specific GPER1 knockout but obviously mitigated by hepatic GPER1 activation in female and male mice. Mechanistically, hepatic GPER1 activates AMP-activated protein kinase signaling by inducing cyclic AMP release, thereby exerting its protective effect. These data suggest that GPER1 may be a promising therapeutic target for NASH.

Dihydrotanshinone I attenuates estrogen-deficiency bone loss through RANKL-stimulated NF-κB, ERK and NFATc1 signaling pathways

Postmenopausal osteoporosis, a chronic condition that predominantly affects postmenopausal women, presents a significant impediment to their overall well-being. The condition arises from estrogen deficiency, leading to enhanced osteoclast activity. Salvia miltiorrhiza, a well-established Chinese herbal medicine with a history of clinical use for osteoporosis treatment, contains diverse active constituents that have shown inhibitory effects on osteoclast formation and bone loss. Dihydrotanshinone I (DTI), a phenanthrenonequinone compound derived from the root of Salvia miltiorrhiza, has been identified as a potential therapeutic agent, although its mechanism of action on osteoclasts remains elusive. In this study, we aimed to elucidate the inhibitory potential of DTI on RANKL-induced osteoclastogenesis. We observed the ability of DTI to effectively impede the expression of key osteoclast-specific genes and proteins, as assessed by Real-time PCR and Western Blotting analyses. Mechanistically, DTI exerted its inhibitory effects on osteoclast formation by modulating critical signaling pathways including NF-κB, ERK, and calcium ion signaling. Notably, DTI intervention disrupted the nuclear translocation and subsequent transcriptional activity of the NFATc1, thus providing mechanistic insights into its inhibitory role in osteoclastogenesis. To further assess the therapeutic potential of DTI, we employed an ovariectomized osteoporosis animal model to examine its impact on bone loss. Encouragingly, DTI demonstrated efficacy in mitigating bone loss induced by estrogen deficiency. In conclusion, our investigation elucidates the ability of DTI to regulate multiple signaling pathways activated by RANKL, leading to the inhibition of osteoclast formation and prevention of estrogen-deficiency osteoporosis. Consequently, DTI emerges as a promising candidate for the treatment of osteoporosis.

Safranal inhibits estrogen-deficiency osteoporosis by targeting Sirt1 to interfere with NF-κB acetylation

BACKGROUND

Osteoporosis is a prevalent bone metabolic disease in menopause, and long-term medication is accompanied by serious side effects. Estrogen deficiency-mediated hyperactivated osteoclasts is the initiating factor for bone loss, which is regulated by nuclear factor-κB (NF-κB) signaling. Safranal (Saf) is a monoterpene aldehyde produced from Saffron (Crocus sativus L.) and possesses multiple biological properties, particularly the anti-inflammatory property. However, Saf's role in osteoporosis remains unknown.

PURPOSE

This study aims to validate the role of Saf in osteoporosis and explore the potential mechanism.

STUDY DESIGN

The RANKL-exposed mouse BMM (bone marrow monocytes) and the castration-mediated osteoporosis model were applied to explore the effect and mechanism of Saf in vitro and in vivo.

METHOD

The effect of Saf on osteoclast formation and function were assessed by TRAcP staining, bone-resorptive experiment, qPCR, immunoblotting and immunofluorescence, etc. Micro-CT, HE, TRAcP and immunohistochemical staining were performed to estimate the effects of Saf administration on OVX-mediated osteoporosis in mice at imaging and histological levels.

RESULTS

Saf concentration-dependently inhibited RANKL-mediated osteoclast differentiation without affecting cellular viability. Meanwhile, Saf-mediated anti-osteolytic capacity and Sirt1 upregulation were also found in ovariectomized mice. Mechanistically, Saf interfered with NF-κB signaling by activating Sirt1 to increase p65 deacetylation and inactivating IKK to decrease IκBα degradation.

CONCLUSION

Our results support the potential application of Saf as a therapeutic agent for osteoporosis.

Women With Turner Syndrome Are Both Estrogen and Androgen Deficient: The Impact of Hormone Replacement Therapy

CONTEXT

Women with Turner syndrome (TS) suffer from hypergonadotropic hypogonadism, causing a deficit in gonadal hormone secretion. As a consequence, these women are treated with estrogen from the age of 12 years, and later in combination with progesterone. However, androgens have been given less attention.

OBJECTIVE

To assess sex hormone levels in women with TS, both those treated and those nontreated with hormone replacement therapy (HRT), and investigate the impact of HRT on sex hormone levels.

METHODS

At Aarhus University Hospital, 99 women with TS were followed 3 times from August 2003 to February 2010. Seventeen were lost during follow-up. Control group 1 consisted of 68 healthy age-matched control women seen once during this period. Control group 2 consisted of 28 young, eumenorrheic women sampled 9 times throughout the same menstrual cycle. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17β-estradiol, estrone sulfate, DHEAS, testosterone, free androgen index, androstenedione, 17-OH progesterone, and sex hormone-binding globulin (SHBG) were analyzed.

RESULTS

All androgens, 17-OH progesterone, and sex hormone-binding globulin (SHBG) were 30% to 50% lower in TS compared with controls (P < 0.01). FSH, LH, and estrone sulfate were more than doubled in women with TS compared with controls (P < 0.02). Using principal component analysis, we describe a positive correlation between women with TS receiving HRT, elevated levels of SHBG, and decreased levels of androgens.

CONCLUSION

The sex hormone profile in TS reveals a picture of androgen deficiency, aggravated further by HRT. Conventional HRT does not normalize estradiol levels in TS.

Combination of molecular docking and liver transcription sequencing analysis for the evaluation of salt-processed psoraleae fructus-induced hepatotoxicity in ovariectomized mice

ETHNOPHARMACOLOGICAL RELEVANCE

Salt-processed Psoraleae fructus (SPF) is widely used as a phytoestrogen-like agent in the treatment of osteoporosis. However, SPF-associated hepatotoxicity is a known health hazard. Cholestasis is often associated with SPF-induced hepatotoxicity. Notably, clinical liver injury is a common side effect of SPF in the treatment of osteoporosis; however, the exact mechanism underlying this phenomenon is unclear.

AIM OF THE STUDY

To evaluate SPF-induced hepatotoxicity in an ovariectomized murine model of estrogen deficiency and examine the mechanisms underlying this process.

MATERIALS AND METHODS

To explore the molecular mechanism of SPF-induced cholestatic liver injury, different concentrations of SPF (5 and 10 g/kg) were intragastrically administered to ovariectomized and non-ovariectomized female ICR mice for 30 days.

RESULTS

SPF-treated mice showed noticeably swollen hepatocytes, dilated bile ducts, and elevated levels of serum biochemical markers. Compared to ovariectomized mice, these changes were more prominent in non-ovariectomized mice. According to the sequence data, a total of 6689 mRNAs were identified. Compared with the control group, 1814 differentially expressed mRNAs were identified in the group treated with high SPF doses (SPHD), including 939 upregulated and 875 downregulated mRNAs. Molecular docking and Western blot experiments showed that liver injury was closely related to the estrogen levels. Compared with the negative control group, the expression levels of FXR, Mrp2, CYP7a1, BSEP, SULT1E1, HNF4a, and Nrf2 decreased in the estradiol-treated (E2), low-dose SPF-treated (SPLD), and SPHD groups. Interestingly, the expression levels of FXR, CYP7a1, SULT1E1, and HNF4α were significantly higher in the ovariectomized groups than in the non-ovariectomized groups (#P < 0.05; ###P < 0.001).

CONCLUSIONS

Overall, this study demonstrates that SPF downregulates key enzymes involved in cholesterol and bile acid biosyntheses, posing a risk for cholestatic liver injury. SPF also regulates the FXR-SULT1E signaling pathway via HNF4α, which is an important causative factor of cholestasis. Moreover, the severity of liver damage was significantly lower in the ovariectomized groups than in the non-ovariectomized group. These results suggest that the estrogen level is the most critical factor determining liver injury.

Gut microbiota and butyrate contribute to nonalcoholic fatty liver disease in premenopause due to estrogen deficiency

The incidence of nonalcoholic fatty liver disease (NAFLD) in postmenopausal women has increased significantly. Estrogen plays a very important role in NAFLD, but whether NAFLD in premenopausal women was caused by estrogen deficiency was unknown. Thus, it is of great clinical significance to explore the mechanism of NAFLD in premenopausal women. Gut microbiota and its metabolites short chain fatty acids (SCFA) have been shown to play important roles in the development of NAFLD. In this study, we investigated the impact of gut microbiota and SCFA in NAFLD patients and mice caused by estrogen deficiency. We showed that premenopause NAFLD patients had much lower estrogen levels. Estrogen deficient mice, due to ovariectomy (OVX), suffered more severe liver steatosis with an elevated body weight, abdominal fat weight, serum triglycerides and deterioration in hepatic steatosis. Altered gut microbiota composition and decreased butyrate content were found in NAFLD patients and in OVX mice. Furthermore, fecal microbiota transplantation (FMT) or supplementing with butyrate alleviated NAFLD in OVX mice. The production of antimicrobial peptides (AMP) Reg3ɣ, β-defensins and the expression of intestinal epithelial tight junction, including ZO-1 and Occluding-5, were decreased in the OVX mice compared to control mice. Upregulation of PPAR-ɣ and VLDLR, downregulation of PPAR-ɑ indicated that OVX mice suffered from abnormal lipid metabolism. These data indicate that changes in the gut microbiota and SCFA caused by estrogen reduction, together with a disorder in AMP production and lipid metabolism, promote NAFLD, thus provide SCFAs derived from microbiota as new therapeutic targets for the clinical prevention and treatment of NAFLD.

Unique Transcriptomic Changes Underlie Hormonal Interactions During Mammary Histomorphogenesis in Female Pigs

Successful lactation and the risk for developing breast cancer depend on growth and differentiation of the mammary gland (MG) epithelium that is regulated by ovarian steroids (17β-estradiol [E] and progesterone [P]) and pituitary-derived prolactin (PRL). Given that the MG of pigs share histomorphogenic features present in the normal human breast, we sought to define the transcriptional responses within the MG of pigs following exposure to all combinations of these hormones. Hormone-ablated female pigs were administered combinations of E, medroxyprogesterone 17-acetate (source of P), and either haloperidol (to induce PRL) or 2-bromo-α-ergocryptine. We subsequently monitored phenotypic changes in the MG including mitosis, receptors for E and P (ESR1 and PGR), level of phosphorylated STAT5 (pSTAT5), and the frequency of terminal ductal lobular unit (TDLU) subtypes; these changes were then associated with all transcriptomic changes. Estrogen altered the expression of approximately 20% of all genes that were mostly associated with mitosis, whereas PRL stimulated elements of fatty acid metabolism and an inflammatory response. Several outcomes, including increased pSTAT5, highlighted the ability of E to enhance PRL action. Regression of transcriptomic changes against several MG phenotypes revealed 1669 genes correlated with proliferation, among which 29 were E inducible. Additional gene expression signatures were associated with TDLU formation and the frequency of ESR1 or PGR. These data provide a link between the hormone-regulated genome and phenome of the MG in a species having a complex histoarchitecture like that in the human breast, and highlight an underexplored synergy between the actions of E and PRL during MG development.

Osteoporosis Due to Hormone Imbalance: An Overview of the Effects of Estrogen Deficiency and Glucocorticoid Overuse on Bone Turnover

Osteoporosis is a serious health issue among aging postmenopausal women. The majority of postmenopausal women with osteoporosis have bone loss related to estrogen deficiency. The rapid bone loss results from an increase in bone turnover with an imbalance between bone resorption and bone formation. Osteoporosis can also result from excessive glucocorticoid usage, which induces bone demineralization with significant changes of spatial heterogeneities of bone at microscale, indicating potential risk of fracture. This review is a summary of current literature about the molecular mechanisms of actions, the risk factors, and treatment of estrogen deficiency related osteoporosis (EDOP) and glucocorticoid induced osteoporosis (GIOP). Estrogen binds with estrogen receptor to promote the expression of osteoprotegerin (OPG), and to suppress the action of nuclear factor-κβ ligand (RANKL), thus inhibiting osteoclast formation and bone resorptive activity. It can also activate Wnt/β-catenin signaling to increase osteogenesis, and upregulate BMP signaling to promote mesenchymal stem cell differentiation from pre-osteoblasts to osteoblasts, rather than adipocytes. The lack of estrogen will alter the expression of estrogen target genes, increasing the secretion of IL-1, IL-6, and tumor necrosis factor (TNF). On the other hand, excessive glucocorticoids interfere the canonical BMP pathway and inhibit Wnt protein production, causing mesenchymal progenitor cells to differentiate toward adipocytes rather than osteoblasts. It can also increase RANKL/OPG ratio to promote bone resorption by enhancing the maturation and activation of osteoclast. Moreover, excess glucocorticoids are associated with osteoblast and osteocyte apoptosis, resulting in declined bone formation. The main focuses of treatment for EDOP and GIOP are somewhat different. Avoiding excessive glucocorticoid use is mandatory in patients with GIOP. In contrast, appropriate estrogen supplement is deemed the primary treatment for females with EDOP of various causes. Other pharmacological treatments include bisphosphonate, teriparatide, and RANKL inhibitors. Nevertheless, more detailed actions of EDOP and GIOP along with the safety and effectiveness of medications for treating osteoporosis warrant further investigation.

Voluntary wheel running alters markers of amyloid-beta precursor protein processing in an ovarian hormone depleted model

INTRODUCTION

Aberrant cleavage of the transmembrane protein, amyloid-beta precursor protein (ABPP), results in the overproduction of amyloid-beta (AB) peptides which can form senile plaques in the brain. These plaques can get lodged within synapses and disrupt neuronal communication ultimately leading to rampant neuron death. The rate-limiting enzyme in AB production is beta-site ABPP cleaving enzyme 1 (BACE1). In females, estrogen loss is associated with increases in AB and BACE1 content and activity. Exercise is known to have anti-amyloidogenic effects and may be able to alter BACE1 in cases of ovarian hormone depletion. This study aimed to examine the effects of physical activity on BACE1 in intact and ovariectomized female mice.

METHODS

Female C57BL/6 mice (24 weeks old) underwent bilateral ovariectomy (OVX; n=20) or SHAM surgery (SHAM; n=20). Mice were assigned to one of four groups (n=10/group) for 8 weeks: (1) sham (SHAM), (2) sham with a wheel (SHAM VWR), (3) ovariectomized (OVX), or (4) ovariectomized with a wheel (OVX VWR).

RESULTS

Novel object recognition testing demonstrated that OVX mice had a lower percentage of novel object investigation time compared to SHAM. OVX mice also had higher prefrontal cortex BACE1 activity compared to SHAM (p<0.0001), while the OVX+VWR activity was not different from SHAM.

DISCUSSIONS

Our results demonstrate that voluntary wheel running in an ovariectomized model prevented increases in BACE1 activity, maintained memory recall, and may provide a method of slowing the progression of Alzheimer's disease.

The relationship of telmisartan with sclerostin in the osteoporosis model induced by ovariectomy in rats

OBJECTIVES

Our aim is to explain the relationship between Ang II and Scl in osteoporotic (OP) rats and the contribution of Scl in the antiosteoporotic effect mechanism of angiotensin receptor blockers (ARB).

METHODS

This study consists of two sub-studies conducted on 4th and 12th weeks after ovariectomy. In study 1, treatment was started immediately after bilateral ovariectomy (OVX), while, in study 2, treatment was started 2 months after OVX. Two different doses of telmisartan (5 and 10 mg/kg) were administered with the aid of gavage for 30 days in both sub-study groups.

RESULTS

Serum and tissue Scl, osteocalcin, osteopontin and tartrate-resistant acid phosphatase mRNA expressions were higher and bone mineral densities (BMD) and bone-specific alkaline phosphatase (BALP) mRNA expressions were found to be lower in the OVX groups compared with the sham group. In OVX groups where two different doses of telmisartan were administered, BMD and BALP mRNA expressions increased and serum and tissue Scl decreased.

CONCLUSION

There may be a close relationship between angiotensin II and sclerostin in the development of osteoporosis. In this study, telmisartan administration showed an antiosteoporotic effect and significantly decreased the level of sclerostin. These results strongly support this relationship.

Estrogen-dependent KCa1.1 modulation is essential for retaining neuroexcitation of female-specific subpopulation of myelinated Ah-type baroreceptor neurons in rats

Female-specific subpopulation of myelinated Ah-type baroreceptor neurons (BRNs) in nodose ganglia is the neuroanatomical base of sexual-dimorphic autonomic control of blood pressure regulation, and KCa1.1 is a key player in modulating the neuroexcitation in nodose ganglia. In this study we investigated the exact mechanisms underlying KCa1.1-mediated neuroexcitation of myelinated Ah-type BRNs in the presence or absence of estrogen. BRNs were isolated from adult ovary intact (OVI) or ovariectomized (OVX) female rats, and identified electrophysiologically and fluorescently. Action potential (AP) and potassium currents were recorded using whole-cell recording. Consistently, myelinated Ah-type BRNs displayed a characteristic discharge pattern and significantly reduced excitability after OVX with narrowed AP duration and faster repolarization largely due to an upregulated iberiotoxin (IbTX)-sensitive component; the changes in AP waveform and repetitive discharge of Ah-types from OVX female rats were reversed by G1 (a selective agonist for estrogen membrane receptor GPR30, 100 nM) and/or IbTX (100 nM). In addition, the effect of G1 on repetitive discharge could be completely blocked by G15 (a selective antagonist for estrogen membrane receptor GPR30, 3 μM). These data suggest that estrogen deficiency by removing ovaries upregulates KCa1.1 channel protein in Ah-type BRNs, and subsequently increases AP repolarization and blunts neuroexcitation through estrogen membrane receptor signaling. Intriguingly, this upregulated KCa1.1 predicted electrophysiologically was confirmed by increased mean fluorescent intensity that was abolished by estrogen treatment. These electrophysiological findings combined with immunostaining and pharmacological manipulations reveal the crucial role of KCa1.1 in modulation of neuroexcitation especially in female-specific subpopulation of myelinated Ah-type BRNs and extend our current understanding of sexual dimorphism of neurocontrol of BP regulation.

The Renin-Angiotensin-Aldosterone System in Postmenopausal Women: The Promise of Hormone Therapy

Estradiol (E2) plays an underrecognized role in modulating body-wide systems, including important interactions with the renin-angiotensin-aldosterone system (RAAS). The RAAS is an immunomodulating system that is critical for maintaining homeostasis across multiple organ systems. The diverse interactions between E2 and the RAAS help maintain cardiometabolic homeostasis, including successful physiologic responses to trauma and infectious pathogens. Estradiol deficiency (ie, menopause) results in impaired responses and increased susceptibility to infectious pathogens. Both immune and cardiometabolic function decline with reduced E2 production, in part because the RAAS becomes dysregulated by E2 deficiency, leaving RAAS predominantly in its proinflammatory state and predisposing to systemic low-grade inflammation. Estradiol deficiency and RAAS dysregulation contribute to impaired immune responses and increased incidence of cardiac hypertrophy, hypertension, atherosclerotic cardiovascular disease, arrhythmias, and heart failure. The RAAS consists of dual, counterbalancing pathways-proinflammatory and anti-inflammatory. Estradiol is a signaling agent that plays a major role in determining which RAAS pathway predominates. The proinflammatory pathway is activated early in response to infection or trauma, followed by up-regulation of the anti-inflammatory pathway, to resolve inflammation and to restore homeostasis. Estradiol influences activation of the "switch" to restore the anti-inflammatory state. The dysregulated RAAS is a primary target of current cardiovascular therapeutics focused on blocking portions of its proinflammatory pathway. However, RAAS-modifying pharmaceuticals often provide imperfect solutions to these physiologic disruptions and underscore the need for improved approaches to menopausal medicine. Estradiol therapy and optimal lifestyle practices combined with RAAS-modifying pharmaceuticals may be an ideal strategy to optimize postmenopausal health.

Osteocytes and Estrogen Deficiency

PURPOSE OF REVIEW

Postmenopausal osteoporosis reduces circulating estrogen levels, which leads to osteoclast resorption, bone loss, and fracture. This review addresses emerging evidence that osteoporosis is not simply a disease of bone loss but that mechanosensitive osteocytes that regulate both osteoclasts and osteoblasts are also impacted by estrogen deficiency.

RECENT FINDINGS

At the onset of estrogen deficiency, the osteocyte mechanical environment is altered, which coincides with temporal changes in bone tissue composition. The osteocyte microenvironment is also altered, apoptosis is more prevalent, and hypermineralization occurs. The mechanobiological responses of osteocytes are impaired under estrogen deficiency, which exacerbates osteocyte paracrine regulation of osteoclasts. Recent research reveals changes in osteocytes during estrogen deficiency that may play a critical role in the etiology of the disease. A paradigm change for osteoporosis therapy requires an advanced understanding of such changes to establish the efficacy of osteocyte-targeted therapies to inhibit resorption and secondary mineralization.

Influence of hormonal imbalance on the integrity of seminiferous epithelium in the testes of adult rats chronically exposed to letrozole and rats exposed to soya isoflavones during the prenatal period, lactation, and up to sexual maturity

The structural integrity of the germ cells in the seminiferous epithelium and the correct process of spermatogenesis are made possible by proteins that participate in the formation of different types of junctions. This study was performed on samples of the testes of 4 groups (2 experimental and 2 corresponding control) of male Wistar rats. In the first experimental group, the adult rats received letrozole - a nonsteroidal inhibitor of cytochrome P450 aromatase (P450arom). The second experimental group was exposed to soya isoflavones during the prenatal period, lactation, and up to sexual maturity. The aim of this study was to examine the immunoexpression of β-catenin, N-cadherin, occludin, connexin43, annexin V, and advanced glycation end products (AGE) in the seminiferous epithelium of rat testes with chronic estrogen deficiency and of rats exposed to soya isoflavones. Series of sections of the testes were stained using PAS and silver impregnation. Moreover, immunohistochemistry tests were performed. A semi-quantitative determination of protein immunoexpression was performed using Image J. The number of annexin V positive Sertoli cells per tubule were counted manually. Comparisons between the experimental and corresponding control groups were performed using a non-parametric Mann-Whitney U test. The most common alterations were prematurely sloughed germ cells in the lumen of the seminiferous tubules and invaginations of the seminiferous tubules. We observed a lower number of annexin V positive Sertoli cells and a lower expression of N-cadherin and occludin in the seminiferous epithelium of both groups of rats with hormonal imbalances. Moreover, a higher expression of AGE, a lower expression of connexin 43 and a lower amount of reticular fibers in the basal lamina of seminiferous tubules was present in rats treated with letrozole and a higher expression of β-catenin was found in rats exposed to soya isoflavones. The hormonal imbalance between androgens and estrogens resulted in a decreased number of annexin V positive Sertoli cells. This may be associated with a failed clearance of apoptotic germ cells that leads to disturbances in the blood-testis-barrier (BTB) by affecting the expression of junctional proteins in the seminiferous epithelium. Moreover, a decreased level of estrogens was also associated with an increased expression of AGEs and with a changed composition of basal lamina in the seminiferous tubules of rats. These changes could lead to germ cell sloughing and invaginations of the seminiferous tubules.

Phytoestrogens (Resveratrol and Equol) for Estrogen-Deficient Skin-Controversies/Misinformation versus Anti-Aging In Vitro and Clinical Evidence via Nutraceutical-Cosmetics

The overarching theme for this review is perspective. Superfoods (a marketing term for fruits and vegetables, etc.) have a positive connotation, while many superfoods contain phytoestrogens, a term that is alarming to the public and has a negative connotation because phytoestrogens are endocrine-disruptors, even though they are strong antioxidants that have many health benefits. To understand phytoestrogens, this paper provides a brief summary of the characteristics of: (a) estrogens, (b) estrogen receptors (ER), (c) estrogen-deficient skin, (d) how perspective(s) get off track, (e) phytoestrogen food sources, and (f) misconceptions of phytoestrogens and food safety, in general, that influence person(s) away from what is true. Finally, a brief history of cosmetics to nutraceuticals is covered plus the characteristics of phytoestrogens, resveratrol and equol on: (g) estrogen receptor binding, (h) topical and oral dosing, and (i) in vitro, molecular mechanisms and select clinical evidence, where both phytoestrogens (resveratrol and equol) demonstrate promising applications to improve skin health is presented along with future directions of nutraceuticals. Perspective is paramount in understanding the controversies associated with superfoods, phytoestrogens, and endocrine-disruptors because they have both positive and negative connotations. Everyone is exposed to and consumes these molecules everyday regardless of age, gender, or geographic location around the world, and how we understand this is a matter of perspective.

Clinical manifestations and evaluation of postmenopausal vulvovaginal atrophy

INTRODUCTION

It is estimated that 50% of women will suffer a severe form of vulvovaginal atrophy (VVA) related to menopause. Equally, young women may temporarily present this clinical problem while receiving various pharmacological or endocrine treatments or radiotherapy.

AIM

To determine clinical and diagnostic exams required to confirm the presence of VVA (also referred to as atrophic vaginitis, urogenital atrophy, or genitourinary syndrome of menopause) and rule out other genital or pelvic clinical conditions.

MATERIALS AND METHODS

Literature review searches were carried out on the main scientific article search engines (PubMed, SciELO, Cochrane) using different clinical terms, treatments or interventions and comorbidity related to VVA.

RESULTS

The development and severity of VVA depend mainly on the duration of hypoestrogenism. Hypoestrogenism causes changes in the urogenital tissue, generating signs and symptoms, such as dryness, burning, soreness, itching, and irritation of the genital skin. The diagnosis can be made through anamnesis (patient history), questionnaires, physical exam, and, sometimes, complementary exams. Objective vaginal assessment is essential and can be completed with the Vaginal Health Index, the Vaginal Maturation Index, or vaginal pH in the absence of infection or semen. The exclusion of other vulvovaginal organic pathology is essential to reach an accurate diagnosis and provide adequate treatment.

CONCLUSIONS

The specialist should be able to identify VVA, rule out other pathologies that make a differential diagnosis and conduct proper management.

The mechanism of pyrroloquinoline quinone influencing the fracture healing process of estrogen-deficient mice by inhibiting oxidative stress

It is reported that oxidative stress plays a detrimental role in the process of bone fracture healing. And pyrroloquinoline quinone (PQQ) is used as antioxidant. However, there is no report about whether PQQ supplementation can promote fracture healing by eliminating oxidative stress. To investigate the protective effect of PQQ on fracture healing, open mid-diaphyseal femur fractures model were created in sham, ovariectomized (OVX) mice and PQQ-treated OVX mice. Our results confirmed that PQQ played a preventive and protective role in OVX-induced delay of bone fracture healing by inhibiting oxidative stress, subsequently promoting osteoblastic bone formation and inhibiting osteoclastic bone resorption. The findings of this study not only revealed the mechanism of PQQ supplementation in promoting fracture healing, but also provide experimental and theoretical basis for the clinical application of PQQ in the treatment of bone fracture.

T-Cell Mediated Inflammation in Postmenopausal Osteoporosis

Osteoporosis is the most prevalent metabolic bone disease that affects half the women in the sixth and seventh decade of life. Osteoporosis is characterized by uncoupled bone resorption that leads to low bone mass, compromised microarchitecture and structural deterioration that increases the likelihood of fracture with minimal trauma, known as fragility fractures. Several factors contribute to osteoporosis in men and women. In women, menopause - the cessation of ovarian function, is one of the leading causes of primary osteoporosis. Over the past three decades there has been growing appreciation that the adaptive immune system plays a fundamental role in the development of postmenopausal osteoporosis, both in humans and in mouse models. In this review, we highlight recent data on the interactions between T cells and the skeletal system in the context of postmenopausal osteoporosis. Finally, we review recent studies on the interventions to ameliorate osteoporosis.

Estrogen receptor α in mature osteoblasts regulates the late stage of bone regeneration

Estrogen deficiency impairs fracture healing and homeostasis of bone tissue. OVX-induced estrogen deficiency in mice attenuates fracture healing and changes the expression ratio of estrogen receptor (ER) α and ERβ in callus during the process of fracture healing. Therefore, ERs may be involved in the regulation of fracture healing. However, the roles of ERs in fracture healing are largely unknown. The purpose of this study was to clarify the significance of ERs during fracture healing using osteoblast-specific ER knockout mice in a mono-cortical drill hole bone regeneration model. The mature osteoblast-specific ER knockout mice were generated using osteocalcin (OCN)-Cre mice, and ERα and ERβ flox mice (OCN-Cre; ERαf/f, ERαΔOb/ΔOb and OCN-Cre; ERβf/f, ERβΔOb/ΔOb). Drill hole surgery was conducted on the tibiae of 8-week-old female mice. The mice were sacrificed 10 or 14 days after surgery and the bones were analyzed by DXA, μCT and bone histomorphometry. DXA analysis revealed that intact femoral BMD was significantly decreased in ERαΔOb/ΔOb mice compared with ERαf/f mice, but there was no difference in bone mass between ERβΔOb/ΔOb and ERβf/f mice. Micro CT analyses showed that the callus volume at the restricted drill hole site in tibiae was significantly less in ERαΔOb/ΔOb compared to ERαf/f mice only at day 14 but not at day 10. In addition to femoral BMD, there was no significant difference in callus volume between ERβΔOb/ΔOb and ERβf/f mice. Bone histomorphometric analyses showed that Ob.S/BS and N.Ob/B.Pm were significantly less in ERαΔOb/ΔOb mice compared with ERαf/f mice only at day 10. In addition, Oc.S/BS and N.Oc/B.Pm were significantly less in ERαΔOb/ΔOb mice compared with ERαf/f mice only at day 14. These results suggest that ERα but not ERβ in osteocalcin-positive osteoblasts may contribute to the late stage of bone regeneration.

Treadmill Exercise Reverses the Change of Dendritic Morphology and Activates BNDF-mTOR Signaling Pathway in the Hippocampus and Cerebral Cortex of Ovariectomized Mice

A decline of estrogen level leads to spatial learning and memory impairments, which mediated by hippocampus and cortex. Accumulating evidences demonstrated that aerobic exercise improved memory of postmenopausal women and ovariectomized (OVX) mice. However, the molecular mechanisms for this protection of exercise are not completely clear. Accordingly, the present study was designed to examine the effect of aerobic exercise on the dendritic morphology in the hippocampus and cerebral cortex, as well as the BNDF-mTOR signaling pathway of OVX mice. Adult female C57BL/6 mice were divided into four groups (n = 10/group): sham-operated (SHAM/CON), sham-operated with 8-week treadmill exercise (SHAM/EX), ovariectomized operated (OVX/CON), and ovariectomized operated with exercise (OVX/EX). Aerobic exercise improved the impairment of dendritic morphology significantly induced by OVX that was tested by Golgi staining, and it also upregulated the synaptic plasticity-related protein expression of PSD95 and GluR1 as well as activated BDNF-mTOR signaling pathway in the hippocampus and cerebral cortex. In conclusion, aerobic exercise reversed the change of dendritic morphology and increased the synaptic plasticity-related protein expression in the hippocampus and cerebral cortex of OVX mice. The positive effects induced by exercise might be mediated through the BDNF-mTOR signaling pathway.

Estrogens in schizophrenia: progress, current challenges and opportunities

PURPOSE OF REVIEW

Schizophrenia is a heterogeneous psychiatric disorder with a different, but not necessarily milder clinical presentation in women as compared to men. These sex differences have largely been attributed to the protective role of estrogens. This article reviews the current state of estrogen research in schizophrenia.

RECENT FINDINGS

Estrogens regulate important pathophysiological pathways in schizophrenia, including dopamine activity, mitochondrial function, and the stress system. Estrogen deficiency is common in both sexes and is associated with increases in psychotic symptoms. Hyperprolactinemia causes secondary estrogen deficiency and can be a reaction to stress, or secondary to prolactin-raising antipsychotics. Therefore, prolactin-sparing antipsychotics should be preferred especially in premenopausal women, who are more prone to hyperprolactinemia. Premenopausal women furthermore require lower doses of antipsychotics than men, since estrogens raise the availability and efficacy of antipsychotics.

SUMMARY

The past years have established the importance of estrogens in the pathophysiology of schizophrenia and have shown its relevance to clinical practice through its influence on antipsychotic drug efficacy. Future research should focus on the neurobiological and clinical effect of contraceptives in premenopausal women with schizophrenia. Furthermore, the potential of estrogen-like augmentation with raloxifene and phytoestrogens in schizophrenia should be established in the coming years.

Effects of estrogen deficiency on liver function and uterine development: assessments of Medicago sativa's activities as estrogenic, anti-lipidemic, and antioxidant agents using an ovariectomized mouse model

We investigated the effects of Medicago sativa supplementation on the lipid profiles and antioxidant capacities of ovariectomized mice.The study was performed on white Swiss female mice that were divided into five groups: control, treated with Medicago sativa (0.75 g/kg/day), ovariectomized, ovariectomized treated with β-estradiol (1 μg/day) or with Medicago sativa. The mice were sacrificed after 3 and 8 weeks of treatment.Ovariectomy induced a decrease in overall growth, uterine atrophy, and hyperlipidemia demonstrated by increased cholesterol, triglycerides, and decreased HDL. We have shown the involvement of oxidative stress in this hepatic lesion proven by increased levels of TBARS, GPX, and GSH, and decreased levels of SOD and catalase.Treatment with Medicago sativa restores lipid balance, the activity of antioxidant enzymes and improves lipid peroxidation. This is probably due to the richness of this plant in polyphenols and flavonoids considered as an antioxidant and phytoestrogenic elements.

Increased cholinergic activity under conditions of low estrogen leads to adverse cardiac remodeling

Cholinesterase inhibitors are used in postmenopausal women for the treatment of neurodegenerative diseases. Despite their widespread use in the clinical practice, little is known about the impact of augmented cholinergic signaling on cardiac function under reduced estrogen conditions. To address this gap, we subjected a genetically engineered murine model of systemic vesicular acetylcholine transporter overexpression (Chat-ChR2) to ovariectomy and evaluated cardiac parameters. Left-ventricular function was similar between Chat-ChR2 and wild-type (WT) mice. Following ovariectomy, WT mice showed signs of cardiac hypertrophy. Conversely, ovariectomized (OVX) Chat-ChR2 mice evolved to cardiac dilation and failure. Transcript levels for cardiac stress markers atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) were similarly upregulated in WT/OVX and Chat-ChR2/OVX mice. 17β-Estradiol (E2) treatment normalized cardiac parameters in Chat-ChR2/OVX to the Chat-ChR2/SHAM levels, providing a link between E2 status and the aggravated cardiac response in this model. To investigate the cellular basis underlying the cardiac alterations, ventricular myocytes were isolated and their cellular area and contractility were assessed. Myocytes from WT/OVX mice were wider than WT/SHAM, an indicative of concentric hypertrophy, but their fractional shortening was similar. Conversely, Chat-ChR2/OVX myocytes were elongated and presented contractile dysfunction. E2 treatment again prevented the structural and functional changes in Chat-ChR2/OVX myocytes. We conclude that hypercholinergic mice under reduced estrogen conditions do not develop concentric hypertrophy, a critical compensatory adaptation, evolving toward cardiac dilation and failure. This study emphasizes the importance of understanding the consequences of cholinesterase inhibition, used clinically to treat dementia, for cardiac function in postmenopausal women.

Impact of estrogen deficiency on diaphragm and leg muscle contractile function in female mdx mice

Female carriers of Duchenne muscular dystrophy (DMD) presenting with DMD symptomology similar to males with DMD, such as skeletal muscle weakness and cardiomyopathy, are termed manifesting carriers. There is phenotypic variability among manifesting carriers including the age of onset, which can range from the first to fourth decade of life. In females, estrogen levels typically begin to decline during the fourth decade of life and estrogen deficiency contributes to loss of muscle strength and recovery of strength following injury. Thus, we questioned whether the decline of estrogen impacts the development of DMD symptoms in females. To address this question, we studied 6-8 month-old homozygous mdx female mice randomly assigned to a sham or ovariectomy (OVX) surgical group. In vivo whole-body plethysmography assessed ventilatory function and diaphragm muscle strength was measured in vitro before and after fatigue. Anterior crural muscles were analyzed in vivo for contractile function, fatigue, and in response to eccentric contraction (ECC)-induced injury. For the latter, 50 maximal ECCs were performed by the anterior crural muscles to induce injury. Body mass, uterine mass, hypoxia-hypercapnia ventilatory response, and fatigue index were analyzed by a pooled unpaired t-test. A two-way ANOVA was used to analyze ventilatory measurements. Fatigue and ECC-injury recovery experiments were analyzed by a two-way repeated-measures ANOVA. Results show no differences between sham and OVX mdx mice in ventilatory function, strength, or recovery of strength after fatigue in the diaphragm muscle or anterior crural muscles (p ≥ 0.078). However, OVX mice had significantly greater eccentric torque loss and blunted recovery of strength after ECC-induced injury compared to sham mice (p ≤ 0.019). Although the results show that loss of estrogen has minimal impact on skeletal muscle contractile function in female mdx mice, a key finding suggests that estrogen is important in muscle recovery in female mdx mice after injury.

Identification of the canonical and noncanonical role of miR-143/145 in estrogen-deficient bone loss

Rationale: Postmenopausal-induced bone loss is mainly caused by declining core transcription factors (TFs) of bone mesenchymal stem cells (BMSCs), but little is known about how miRNAs regulate chromatin structure remodeling of TFs gene to maintain BMSCs function in bone homeostasis. Methods: We examined the serum, salivary and bone samples from Pre- and Post-menopause women by paired analysis and confirmed canonical ceRNA role of MIR143HG and miR-143/145 complexes in cytoplasm and noncanonical role for SOX2 transcription in nucleus (FISH, qRT-PCR, immunostaining, Luciferase assays and ChIP). Moreover, we took advantage of transgenic mice under OVX-induced osteoporosis, studying the in vitro and in vivo effect of miR-143/145 deletion on BMSCs function and bone homeostasis. Last, using miRNA antagonism, antagomiR-143/145 were delivered into bone marrow to treat estrogen-deficient bone loss. Results: Here, we identified miR-143/145 as potential diagnostic candidates for postmenopausal osteoporosis, and miR-143/145 overexpression impaired BMSCs self-renewing and differentiation function. Mechanistically, we confirmed that cytoplasmic miR-143/145 and LncRNA MIR143HG, that controlled by ERβ, cooperatively regulated pluripotency genes translation via canonical ceRNA pathway, and MIR143HG cooperates with miR‑143 to nuclear translocation for co-activation of SOX2 transcription via opening promoter chromatin. Meanwhile, miR‑143/145 were shuttled into osteoclasts in extracellular vesicles and triggered osteoclastic activity by targeting Cd226 and Srgap2. Furthermore, miR-143/145-/- mice or using chemically‑modified antagomiR-143/145 significantly alleviated estrogen-deficient osteoporosis. Conclusions: Our findings reveal a canonical and noncanonical role of miR-143/145 in controlling BMSCs pluripotency and unfold their dual effect on bone formation and bone resorption, suggesting miR-143/145 as promising therapeutic targets for treating estrogen-deficient bone loss.

Improvements in estrogen deficiency-induced hypercholesterolemia by Hypericum perforatum L. extract are associated with gut microbiota and related metabolites in ovariectomized (OVX) rats

Hypericum perforatum L. (HP), a well-known natural medicine, has a potential effect on menopausal hypercholesterolemia. However, the effect of HP extract on gut microbiota and related metabolites, which play vital roles in metabolic disease occurrence, in the context of estrogen deficiency have not yet been reported. The aims of the present study were to investigate the effects of HP extract on gut microbial composition and related metabolite profiles in ovariectomized (OVX) rats and reveal the relationships between pathological indicators and alterations in both gut microbial composition at the genus level and metabolites. Body weight, serum parameters, liver lipids and histomorphology were determined. Microbial composition was analyzed using 16S rRNA sequencing. Fecal short-chain fatty acids (SCFAs) and serum bile acids were quantitatively measured. Correlations between pathological indicators and alteration in gut microbiota and metabolites were investigated using Spearman's rank correlation test. Gene expression of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase (CYP7A1) and cholesterol 27-hydroxylase (CYP27A1) in the liver and G protein-coupled receptors (GPCRs; GPR43 and GPR41), ZO-1 and occludin in the cecum were determined by PCR. Microbial composition and metabolite profiles were significantly changed in OVX rats compared with sham rats. Twelve bacterial genera, 5 SCFAs and 12 bile acids were identified as differential biomarkers. Differential genera, SCFAs and bile acids were closely associated with weight, total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). In OVX rats, HP administration can significantly reverse the pathological symptoms of body weight gain, serum lipid disorders and hepatic steatosis, at the meanwhile, reestablish gut microbial composition and metabolite profiles. Moreover, HP administration significantly upregulated the levels of CYP7A1, GPR43 and GPR41. In conclusion, HP can ameliorate estrogen deficiency-induced hypercholesterolemia. The underlying mechanism may be associated with improvements in gut microbiota composition and the profile of related metabolites as well as increases in bile acid secretion.

Icariin ameliorates estrogen-deficiency induced bone loss by enhancing IGF-I signaling via its crosstalk with non-genomic ERα signaling

BACKGROUND

Rapid, non-genomic estrogen receptor (ER) signaling plays an integral role in mediating the tissue selective properties of ER modulators. Icariin, a bone bioactive flavonoid, has been reported to selectively activate non-genomic ERα signaling in in vitro and in vivo studies.

PURPOSE

The mechanisms underlying the estrogen-like bone protective effects of icariin are not fully understood, especially those that are related to insulin-like growth factor I (IGF-1) signaling. The bone protective effects of icariin were investigated in female mature ovariectomized (OVX) rats and the signaling of IGF-IR- ERα cross-talk was determined in osteoblastic cells.

STUDY DESIGN AND METHODS

Icariin at 3 different dosages (50, 500 and 3000 ppm) were orally administrated to rats for 3 months through daily intake of phytoestrogen-free animal diets containing icariin. Bone marrow stromal cells (BMSCs) and osteoclast precursors from femurs were harvested for experiments and RNA-sequencing. The interactions between IGF-IR and non-genomic ERα signaling were examined in pre-osteoblastic MC3T3-E1 cells and mature osteoblasts differentiated from BMSCs.

RESULTS

Our results show that chronic administration of icariin to OVX rats significantly protected them against bone loss at the long bone and lumbar spine without inducing any uterotrophic effects. Ex vivo studies using BMSCs and osteoclast precursors confirmed the stimulatory effects of icariin on osteoblastogenesis and its inhibitory effects on osteoclastogenesis, respectively. RNA-sequencing analysis of mRNA from BMSCs revealed that icariin at 500 ppm significantly altered IGF-1 signaling as well as PI3K-Akt pathways. Our results demonstrated for the first time the rapid induction of interactions between IGF-IR and ERα as well as IGF-IR signaling and the downstream Akt phosphorylation by icariin in MC3T3-E1 cells. The activation of ERα and Akt phosphorylation by icariin in MC3T3-E1 cells and the osteogenic effects of icariin on ALP activity in mature osteoblasts were shown to be IGF-IR-dependent.

CONCLUSION

Our findings reveal that icariin activates both ERα and Akt via enhancing rapid induction of IGF-1 signaling in osteoblastic cells for osteogenesis and might be regarded as a novel pathway-selective phytoestrogen for management of postmenopausal osteoporosis.

Connexin Gap Junctions and Hemichannels Link Oxidative Stress to Skeletal Physiology and Pathology

PURPOSE OF REVIEW

The goal of this review is to provide an overview of the impact and underlying mechanism of oxidative stress on connexin channel function, and their roles in skeletal aging, estrogen deficiency, and glucocorticoid excess associated bone loss.

RECENT FINDINGS

Connexin hemichannel opening is increased under oxidative stress conditions, which confers a cell protective role against oxidative stress-induced cell death. Oxidative stress acts as a key contributor to aging, estrogen deficiency, and glucocorticoid excess-induced osteoporosis and impairs osteocytic network and connexin gap junction communication. This paper reviews the current knowledge for the role of oxidative stress and connexin channels in the pathogenesis of osteoporosis and physiological and pathological responses of connexin channels to oxidative stress. Oxidative stress decreases osteocyte viability and impairs the balance of anabolic and catabolic responses. Connexin 43 (Cx43) channels play a critical role in bone remodeling, mechanotransduction, and survival of osteocytes. Under oxidative stress conditions, there is a consistent reduction of Cx43 expression, while the opening of Cx43 hemichannels protects osteocytes against cell injury caused by oxidative stress.

Arecanut (Areca catechu L.) Seed Polyphenol-Ameliorated Osteoporosis by Altering Gut Microbiome via LYZ and the Immune System in Estrogen-Deficient Rats

Polyphenol can improve osteoporosis and is closely associated with gut microbiota, while the mechanism and the relationship among polyphenol, osteoporosis, and gut microbiota colonization remain unclear. Here, an osteoporosis rat model established by ovariectomy was employed to investigate the improving mechanism of arecanut (Areca catechu L.) seed polyphenol (ACP) on osteoporosis by regulating gut microbiota. We analyzed the bone microstructure, Paneth cells, regulating microbial protein (lysozyme (LYZ)), proinflammatory cytokines, macrophage infiltration levels, and gut microbial communities in a rat. ACP improved the trabecular microstructure compared to OVX, including the increased trabecular number (Tb.N) (P < 0.01) and trabecular thickness (Tb.Th) (P < 0.001) and decreased trabecular separation (Tb.Sp) (P < 0.01). At the phylum level, Bacteroidetes was increased after ovariectomy (P < 0.001) and Firmicutes and Proteobacteria were increased in ACP (P < 0.001). Antiosteoporosis groups with lower LYZ and Paneth cells (P < 0.001) showed that the microbiota Alistipes, which have a negative effect on bone metabolism were decreased in ACP (P < 0.001). Altogether, these studies showed that the estrogen deficiency could induce the shedding of Paneth cells, which leads to the decrease of LYZ, while ACP could increase the LYZ expression by maintaining the population of Paneth cells in an estrogen-deficient host, which were implicated in gut microbiota regulation and improved osteoporosis by controlling the inflammatory reaction.

Inhibition of Lipoxygenases Showed No Benefit for the Musculoskeletal System in Estrogen Deficient Rats

BACKGROUND

In previous studies, we reported the beneficial impact of two lipoxygenase-inhibitors, Baicalein and Zileuton, on osteoporotic bone in a postmenopausal rat model. Whereas subcutaneous Baicalein predominantly improved cortical bone, Zileuton enhanced vertebral and femoral trabecular bone. In this study, we aimed to reveal whether the oral administration of Baicalein caused similar effects on bone and whether a combined administration of Baicalein and Zileuton could act synergistically to ameliorate the formerly reported effects in the musculoskeletal system.

METHODS

We treated ovariectomized (OVX) female Sprague-Dawley rats either with Baicalein (10mg/kg BW), Zileuton (10mg/kg BW) or a combination of both (each 10mg/kg BW) for 13 weeks and compared with untreated OVX and NON-OVX groups (n=12-16 rats per group). Lumbar vertebral bodies and femora were analyzed. Tibiae were osteotomized, plate-stabilized (at week 8 after OVX) and likewise analyzed by biomechanical, histological, micro-computed tomographical and ashing tests. The skeletal muscle structure was analyzed.

RESULTS

Oral administration of Baicalein did not confirm the reported favorable cortical effects in neither vertebra nor femur. Zileuton showed a beneficial effect on trabecular vertebra, while the femur was negatively affected. Callus formation was enhanced by all treatments; however, its density and biomechanical properties were unaltered. Lipoxygenase inhibition did not show a beneficial effect on skeletal muscle. The combination therapy did not ameliorate OVX-induced osteoporosis but induced even more bone loss.

CONCLUSIONS

The preventive anti-osteoporotic treatments with two lipoxygenase inhibitors applied either alone or in combination showed no benefit for the musculoskeletal system in estrogen deficient rats.

Mechanical stress regulates bone regulatory gene expression independent of estrogen and vitamin D deficiency in rats

Mechanical stress determines bone mass and structure. It is not known whether mechanical loading affects expression of bone regulatory genes in a combined deficiency of estrogen and vitamin D. We studied the effect of mechanical loading on the messenger RNA (mRNA) expression of bone regulatory genes during vitamin D and/or estrogen deficiency. We performed a single bout in vivo axial loading with 14 N peak load, 2 Hz frequency and 360 cycles in right ulnae of nineteen weeks old female control Wistar rats with or without ovariectomy (OVX), vitamin D deficiency and the combination of OVX and vitamin D deficiency (N = 10/group). Total bone RNA was isolated 6 hours after loading, and mRNA expression was detected of Mepe, Fgf23, Dmp1, Phex, Sost, Col1a1, Cyp27b1, Vdr, and Esr1. Serum levels of 25(OH)D, 1,25(OH)2 D and estradiol were also measured at this time point. The effect of loading, vitamin D and estrogen deficiency and their interaction on bone gene expression was tested using a mixed effect model analysis. Mechanical loading significantly increased the mRNA expression of Mepe, and Sost, whereas it decreased the mRNA expression of Fgf23 and Esr1. Mechanical loading showed a significant interaction with vitamin D deficiency with regard to mRNA expression of Vdr and Esr1. Mechanical loading affected gene expression of Mepe, Fgf23, Sost, and Esr1 independently of vitamin D or estrogen, indicating that mechanical loading may affect bone turnover even during vitamin D deficiency and after menopause.

Kefir Peptides Prevent Estrogen Deficiency-Induced Bone Loss and Modulate the Structure of the Gut Microbiota in Ovariectomized Mice

Osteoporosis is a major skeletal disease associated with estrogen deficiency in postmenopausal women. Kefir-fermented peptides (KPs) are bioactive peptides with health-promoting benefits that are produced from the degradation of dairy milk proteins by the probiotic microflora in kefir grains. This study aimed to evaluate the effects of KPs on osteoporosis prevention and the modulation of the composition of the gut microbiota in ovariectomized (OVX) mice. OVX mice receiving an 8-week oral gavage of 100 mg of KPs and 100 mg of KPs + 10 mg Ca exhibited lower trabecular separation (Tb. Sp), and higher bone mineral density (BMD), trabecular number (Tb. N) and bone volume (BV/TV), than OVX groups receiving Ca alone and untreated mice, and these effects were also reflected in bones with better mechanical properties of strength and fracture toughness. The gut microbiota of the cecal contents was examined by 16S rDNA amplicon sequencing. α-Diversity analysis indicated that the gut microbiota of OVX mice was enriched more than that of sham mice, but the diversity was not changed significantly. Treatment with KPs caused increased microbiota richness and diversity in OVX mice compared with those in sham mice. The microbiota composition changed markedly in OVX mice compared with that in sham mice. Following the oral administration of KPs for 8 weeks, the abundances of Alloprevotella, Anaerostipes, Parasutterella, Romboutsia, Ruminococcus_1 and Streptococcus genera were restored to levels close to those in the sham group. However, the correlation of these bacterial populations with bone metabolism needs further investigation. Taken together, KPs prevent menopausal osteoporosis and mildly modulate the structure of the gut microbiota in OVX mice.

NAFLD and NASH in Postmenopausal Women: Implications for Diagnosis and Treatment

Nonalcoholic fatty liver disease (NAFLD) prevalence in women is increasing worldwide. Women of reproductive age have lower rates of NAFLD compared with men; however, this protection is lost following the menopausal transition when NAFLD prevalence in postmenopausal women becomes similar to or surpasses that in age-matched male counterparts. Ongoing epidemiological, clinical, and experimental studies indicate greater NAFLD risk and higher rates of severe hepatic fibrosis in postmenopausal women relative to premenopausal women, and that older women with NAFLD experience greater mortality than men. Investigations involving ovariectomized animal models demonstrate a causal relationship between estrogen deficiency and heightened susceptibility to the development of fatty liver and steatohepatitis, although dietary factors may exacerbate this complex relationship. The accumulated findings suggest that a better understanding of the interplay among menopausal status, metabolic comorbidities, and sex steroids in NAFLD pathogenesis is needed. Further, the mechanisms underlying the difference in NAFLD risk between postmenopausal and premenopausal women remain incompletely understood. The goals of this review are to summarize studies of NAFLD risk in postmenopausal women, discuss results from animal models of estrogen deficiency, and explore the development of NAFD within the context of altered sex hormone profiles resulting from the menopausal transition. Potential implications for the prevention, diagnosis, and treatment of NAFLD in this relatively understudied cohort are also addressed.

Effects of estrogen deficiency followed by streptozotocin-induced diabetes on periodontal tissues of female rats

Although both estrogen deficiency and diabetes contribute to periodontal tissue deterioration, the combined effects of these conditions on periodontium is unknown. Thus, we analyzed the combined effects of ovariectomy followed by streptozotocin (STZ)-induced diabetes on periodontal tissues of rats. Twenty adult rats were ovariectomized (OVX) or SHAM-operated (SHAM). After 3 weeks, the rats received an intraperitoneal injection of STZ (60 mg/kg/body weight) to induce diabetes or vehicle (blank) solution. The groups were assigned as follows (n = 5): SHAM-vehicle (SHAM), OVX-vehicle (OVX), SHAM + STZ (SHAM-Di), and OVX + STZ (OVX-Di). Seven weeks post-diabetes induction, the rats were euthanized. Blood samples were collected for glucose measurements and maxillae were processed for paraffin embedding. Sections stained with hematoxylin/eosin, Masson's trichrome, and picrosirius-red were used for alveolar bone loss and collagen fiber analysis in the lamina propria. Immunohistochemistry was performed for runt-related transcription factor 2 (Runx2), matrix metalloproteinase 9 (MMP-9), and tryptase detection. Alveolar bone loss and fewer collagen fibers were observed in the OVX-Di group, collagen fibers with irregular organization, and MMP-9 immunoreactivity were more evident in diabetic groups, and MMP-9-positive osteoclasts on alveolar bone surface were noticed in all groups. The OVX-Di group showed lower Runx2 immunoreactivity (osteoblast formation marker), and more tryptase-positive cells (mast cell marker) in the alveolar bone marrow. Our results indicate that estrogen depletion, followed by STZ-induced diabetes, promotes periodontal tissue deterioration that is more evident than both interventions applied alone. Furthermore, our results points to a possible participation of bone-derived mast cells in this process.

JAK2/STAT3 regulates estrogen-related senescence of bone marrow stem cells

Emerging evidence has indicated that estrogen deficiency contributes to osteoporosis by affecting the level of inflammation. The inflammation microenvironment affects many cellular physiological processes, one of which may be cellular senescence according to previous studies. Senescent cells cannot function normally and secrete inflammatory cytokines and degradative proteins, which are referred to as senescence-associated secretory phenotype (SASP) factors, inducing further senescence and inflammation. Thus, stopping this vicious cycle may be helpful for postmenopausal osteoporosis treatment. Here, we used ovariectomized (OVX) mice as an estrogen-deficient model and confirmed that OVX bone marrow mesenchymal stem cells (BMSCs) displayed a senescent phenotype and upregulated SASP factor secretion both in vitro and in vivo. Furthermore, JAK2/STAT3, an important cytokine secretion-related signalling pathway that is associated with SASP secretion, was activated. Estrogen addition and estrogen receptor blockade confirmed that the JAK2/STAT3 axis participated in OVX BMSC senescence by mediating SASP factors. And JAK inhibition reduced SASP factor expression, alleviated senescence and enhanced osteogenic differentiation. Intraperitoneal injection of a JAK inhibitor, ruxolitinib, prevented bone loss in OVX mice. Collectively, our results revealed that JAK2/STAT3 plays an important role in the inflammation-senescence-SASP feedback loop in OVX BMSCs and that JAK inhibition could be a new method for treating postmenopausal osteoporosis.

Decreased bone mineral density and reproductive axis dysfunction: more than oestrogen

Decreased bone mineral density (BMD) in oestrogendeficient states has long been thought to be a direct outcome of the reduction in oestrogen. In physiologic and many pathologic hypo-oestrogenic states, oestrogen supplementation improves BMD. However, the relationship between oestrogen replacement and BMD is less clear in the case of reproductive axis dysfunction secondary to decreased caloric intake or increased energy expenditure, such as in female athletes or anorexia nervosa. This decrease in oestrogen is associated with decreased BMD, but oestrogen replacement in these states fails to conclusively improve BMD. This suggests that the decrease in BMD in these states is not driven solely by low oestrogen. Cortisol and other markers of inflammation may play a role in BMD reduction but further research is needed. What is clear is that increased caloric consumption and restoration of menses and the reproductive axis are essential to improving BMD, while pharmacologic therapy, including oestrogen replacement through hormone therapy or contraceptives, does not provide conclusive benefit.

Coronary Microvascular Dysfunction and Estrogen Receptor Signaling

Chest pain with non-obstructive coronary artery disease (NOCAD) occurs more frequently in women than in men and is mainly related to coronary microvascular disease (CMD). The majority of CMD patients are postmenopausal women, suggesting a role for lack of estrogens in the development and progression of CMD. Patients are often discharged without a clear treatment plan due to the limited understanding of etiology and diagnostic parameters of CMD and have significantly higher rates of future cardiovascular events. Thus, there is a need for a better understanding of the underlying biology, and CMD-specific diagnostic tests and therapies. In this article, we reviewed recent studies on CMD, estrogen action in coronary microvasculature, and diagnosis and treatment options for CMD in postmenopausal women.

NRF2 deficiency increases obesity susceptibility in a mouse menopausal model

The risk of metabolic abnormalities in menopausal women increases significantly due to the decline in estrogen level. Nuclear factor E2-related factor 2 (NRF2) is an important oxidative stress sensor that plays regulatory role in energy metabolism. Therefore, an ovariectomized menopausal model in Nrf2-knockout (KO) mice was applied to evaluate the effect of Nrf2 deficiency on metabolism in menopausal females. The mice were divided into four groups according to their genotypes and treatments. Blood samples and bodyweights were obtained preoperatively and in the first to ninth postoperative weeks after overnight fasting. Serum levels of triglycerides (TG), total cholesterol (T-CHO), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and glucose (GLU) were measured at postoperative weeks 0, 1, 3, 5, 7, and 9. Neurotransmitter dopamine (DA) and serotonin (5-HT) was analyzed in brain tissues after sacrifice at postoperative week 9. The results demonstrated that, compared with the corresponding wild-type (WT) mice, KO ovariectomized mice had a greater bodyweight gain (P<0.01). Serum analysis showed that the serum GLU, T-CHO, and TG were significantly lower (P<0.05) but LDL was significantly higher (P<0.05) in the KO control mice than that in WT control mice. However, different from the WT counterparts, an increase in blood GLU level (P<0.05), unchanged T-CHO, TG, and HDL levels, and a significant reduction in LDL (P<0.01) was found in the KO ovariectomized mice. In addition, the level of 5-HT was significantly reduced (P<0.05) in the KO mice after ovariectomy. In conclusion, the combination of Nrf2 deletion and a decline in estrogen level induced a significant increase in bodyweight, which may be associated with their altered glucose and LDL metabolism and decreased 5-HT levels. From a clinical perspective, women with antioxidant defense deficiency may have an increased risk of metabolic abnormalities after menopause.

Are Oxidative Stress and Inflammation Mediators of Bone Loss Due to Estrogen Deficiency? A Review of Current Evidence

Osteoporosis is one of the major health issues associated with menopause-related estrogen deficiency. Various reports suggest that the hormonal changes related to menopausal transition may lead to the derangement of redox homeostasis and ultimately oxidative stress. Estrogen deficiency and oxidative stress may enhance the expression of genes involved in inflammation. All these factors may contribute, in synergy, to the development of postmenopausal osteoporosis. Previous studies suggest that estrogen may act as an antioxidant to protect the bone against oxidative stress, and as an antiinflammatory agent in suppressing pro-inflammatory and pro-osteoclastic cytokines. Thus, the focus of the current review is to examine the relationship between estrogen deficiency, oxidative stress and inflammation, and the impacts of these phenomena on skeletal health in postmenopausal women.

Estrogen deficiency induces memory loss via altered hippocampal HB-EGF and autophagy

Estrogen deficiency reduces estrogen receptor-alpha (ERα) and promotes apoptosis in the hippocampus, inducing learning-memory deficits; however, underlying mechanisms remain less understood. Here, we explored the molecular mechanism in an ovariectomized (OVX) rat model, hypothesizing participation of autophagy and growth factor signaling that relate with apoptosis. We observed enhanced hippocampal autophagy in OVX rats, characterized by increased levels of autophagy proteins, presence of autophagosomes and inhibition of AKT-mTOR signaling. Investigating upstream effectors of reduced AKT-mTOR signaling revealed a decrease in hippocampal heparin-binding epidermal growth factor (HB-EGF) and p-EGFR. Moreover, 17β-estradiol and HB-EGF treatments restored hippocampal EGFR activation and alleviated downstream autophagy process and neuronal loss in OVX rats. In vitro studies using estrogen receptor (ERα)-silenced primary hippocampal neurons further corroborated the in vivo observations. Additionally, in vivo and in vitro studies suggested the participation of an attenuated hippocampal neuronal HB-EGF and enhanced autophagy in apoptosis of hippocampal neurons in estrogen- and ERα-deficient conditions. Subsequently, we found evidence of mitochondrial loss and mitophagy in hippocampal neurons of OVX rats and ERα-silenced cells. The ERα-silenced cells also showed a reduction in ATP production and an HB-EGF-mediated restoration. Finally in concordance with molecular studies, inhibition of autophagy and treatment with HB-EGF in OVX rats restored cognitive performances, assessed through Y-Maze and passive avoidance tasks. Overall, our study, for the first time, links neuronal HB-EGF/EGFR signaling and autophagy with ERα and memory performance, disrupted in estrogen-deficient condition.

Pisidium coreanum Inhibits Multinucleated Osteoclast Formation and Prevents Estrogen-Deficient Osteoporosis

Mollusks have served as important sources of human food and medicine for a long time. Raw Pisidium coreanum, a freshwater bivalve of the phylum Mollusca, is used in traditional therapies in parts of Asia. However, the therapeutic effects of Pisidium coreanum on bone diseases are not known. We investigated the functional roles of Pisidium coreanum in osteoporotic bone diseases. Pisidium coreanum inhibited the differentiation of bone marrow-derived monocytic cells into mature osteoclasts in vitro. The ovariectomized mice that received oral administration of Pisidium coreanum showed improvements in both trabecular and cortical bones. This preventive activity of Pisidium coreanum against bone loss was due to limited osteoclast maturation with reduced osteoclast surface extent in trabecular bone tissue. The formation of large multinucleated osteoclasts in vitro was significantly decreased in response to Pisidium coreanum, consistent with the reduced expression levels of osteoclast markers and fusion-related genes, such as NFATc1, p65, integrinαvβ3, DC-STAMP, OC-STAMP, Atp6v0d2, FAK, CD44, and MFR. These data suggest that Pisidium coreanum inhibits osteoclast differentiation by negatively regulating the fusion of mononuclear osteoclast precursors. Thus, our data demonstrate the ability of Pisidium coreanum to effectively prevent estrogen-deficient osteoporosis through inhibition of multinucleated osteoclast formation.

Evaluation of Efficacy of a Skin Care Regimen Containing Methyl Estradiolpropanoate (MEP) for Treating Estrogen Deficient Skin

BACKGROUND: Aging is a complex process due to the interplay of intrinsic factors (such as genetics and hormones) and extrinsic factors (including ultraviolet radiation and pollution). A significant cause of intrinsic aging in women is the loss of estrogen as a result of the onset of menopause. OBJECTIVE: A single site experience trial to assess the efficacy of Emepelle (Biopelle, Ferndale Pharma Group, Ferndale, MI), a skin care regimen containing Methyl Estradiolpropanoate (MEP)®, for the treatment of Estrogen Deficient Skin (EDS). The secondary objective was to assess patient tolerability and satisfaction. METHODS: Fourteen female subjects aged 53-68 years who were amenorrheic for 1-10 years (mean, 5 years), with at least a Grade II in Wrinkling (fine to moderate-depth wrinkles, moderate number of lines) and score of at least 5 (of 9; moderate-to-severe) in elastosis on the clinician-assessed Fitzpatrick-Goldman Classification of Wrinkling and Elastosis Scale, and a 3 or greater on the Investigator Facial Skin Hydration Scale, were included in the study. The subjects were instructed to apply the product Emepelle Serum in the morning, and the product Emepelle Night Cream in the evening to the entire freshly washed and dried face. Follow up visits were performed at 8 weeks, 14 weeks, and 20 weeks to evaluate efficacy and safety. Canfield Visia Complexion Analysis and standard photography was performed at baseline and at each follow up visit. RESULTS: On a 0-4 Facial Hydration Scale, 100% of study participants by week 20 showed at least one-grade improvement and 93% saw two grades or more improvement in hydration. 100% of study participants showed aesthetic improvements per investigator-assessed Global Aesthetic Improvement Scale (GAIS) at week 14. By week 20, 93% of study participants responded that the combination of Emepelle Serum and Night Cream regimen helped improve wrinkles, texture, and color, and 86% of study participants responded that Emepelle helped improve sun-damage, thickness, and integrity. In the Quality of Life questionnaire, 86% responded that Emepelle helped alleviate some or all of the skin issues they developed since entering menopause. Investigator clinical assessment scored patients with a 53% improvement in texture, 21% improvement in keratoses, and 15% improvement in laxity on the Alexiades-Armenakas Comprehensive Grading Scale for Assessment of Skin Aging and Photodamage by the end of the study at week 20. CONCLUSIONS: Patients in the study indicated satisfaction with the formulations of Emepelle Serum and Night Cream. Younger patients showed significant improvement by about 8 weeks. For patients who have been in menopause longer, significant improvement was seen by week 20, suggesting MEP’s potential ability to reactivate dormant estrogen receptors. J Drugs Dermatol. 2019;18(12):1226-1230.

Long-term estrogen deprivation changes the response to antianxiety drugs in mice in the elevated plus maze test

Estrogen deficiency increases the incidence of female anxiety disorders; however, whether estrogen deficiency alters responses to anxiolytic drugs is unknown. We studied whether long-term estrogen deprivation (ovariectomy, OVX) changes the behavior of mice to anxiolytic drugs (buspirone, diazepam, and venlafaxine), using the elevated plus maze (EPM) test. The percentages of EPM open-arm time and EPM open-arm entries of the OVX mice decreased significantly compared to control, and sham mice 2 months after OVX. The response to buspirone increased in the OVX mice at 1 week, while OVX decreased the response to diazepam at 2 months. Moreover, we found the efficacy of diazepam was significantly decreased, compared to buspirone and venlafaxine, at 2 months. These results suggest that OVX may change responses to different anxiolytic drugs. Not all anti-anxiety drugs appear to be suitable for anxiety caused by estrogen deficiency.

Anomalous bone changes in ovariectomized type 2 diabetic rats: inappropriately low bone turnover with bone loss in an estrogen-deficient condition

Estrogen deprivation accelerates bone resorption, leading to imbalance of bone remodeling and osteoporosis in postmenopausal women. In the elderly, type 2 diabetes mellitus (T2DM) frequently coexists as an independent factor of bone loss. However, little is known about the skeletal changes in a combined condition of estrogen deficiency and T2DM. Herein, we performed ovariectomy (OVX) in nonobese Goto-Kakizaki (GK) T2DM rats to examine changes associated with calcium and phosphate metabolism and bone microstructures and strength. As expected, wild-type (WT) rats subjected to ovariectomy (OVX-WT) had low trabecular bone volume and serum calcium with increased dynamic histomorphometric and serum bone markers, consistent with the high turnover state. T2DM in GK rats also led to low trabecular volume and serum calcium. However, the dynamic histomorphometric markers of bone remodeling were unaffected in these GK rats, indicating the distinct mechanism of T2DM-induced bone loss. Interestingly, OVX-GK rats were found to have anomalous and unique changes in bone turnover-related parameters, i.e., decreased osteoblast and osteoclast surfaces with lower COOH-terminal telopeptide of type I collagen levels compared with OVX-WT rats. Furthermore, the levels of calciotropic hormones, i.e., parathyroid hormone and 1,25(OH)₂D₃, were significantly decreased in OVX-GK rats. Although the OVX-induced bone loss did not further worsen in GK rats, a three-point bending test indicated that OVX-GK bones exhibited a decrease in bone elasticity. In conclusion, T2DM and estrogen deficiency both led to microstructural bone loss, the appearance of which did not differ from each factor alone. Nevertheless, the combination worsened the integrity and suppressed the turnover, which might eventually result in adynamic bone disease.

Female-Specific Role of Progranulin to Suppress Bone Formation

Progranulin (PGRN) is best known as a glial protein for which deficiency leads to the most common inherited form of frontotemporal dementia. Recently, PGRN has been found to be an adipokine associated with diet-induced obesity and insulin resistance. Therefore, PGRN may have homeostatic effects on bone because PGRN is reported to promote the differentiation of bone-resorbing osteoclasts. We investigated the actions of PGRN on bone using PGRN gene (Grn) knockout (KO) mice and transgenic mice with PGRN mutation and surprisingly found that loss of PGRN prevented the bone loss in female mice induced by aging and estrogen deficiency, whereas it had no effect on male bones during aging. Strikingly, bone formation was increased in female (but not male) PGRN KO mice. We also found that loss of PGRN inhibited bone resorption and osteoclastogenesis in both male and female mice and promoted the production of osteogenic factors in osteoclast lineage cells. These results indicate that PGRN serves to uncouple bone turnover in female mice by promoting bone resorption and suppressing bone formation. Furthermore, we demonstrated that microglial cells/macrophages, but not adipocytes, are an important source of PGRN in producing negative skeletal effects in females. Targeting PGRN production by microglial cells/macrophage-lineage cells may provide a therapeutic approach for the treatment of osteoporosis in females.

A critical assessment of case reports describing absent uterus in subjects with oestrogen deficiency

OBJECTIVE

The dual diagnosis of hypoplastic uterus in association with ovarian dysgenesis is regularly reported but the pathogenesis of the association is unclear. The uterus, however, may be invisible to all imaging modalities without at least six months of exogenous oestrogen exposure in complete ovarian failure. We assessed all available case reports in this category to estimate whether the apparent association between primary ovarian insufficiency or Turner syndrome and Mullerian agenesis can be largely accounted for by oestrogen deficiency.

DESIGN

A literature review of all cases in which an association between ovarian insufficiency or Turner syndrome and hypoplastic uterus has been reported.

PATIENTS

PubMed was searched for all case reports associated with relevant key terms. In total, 22 publications with a total of 25 patients were identified and reviewed; 14 subjects had the normal female karyotype (46,XX), and 11 subjects had Turner Syndrome.

MEASUREMENTS

Proportion of subjects who had been exposed to adequate oestrogen prior to the absent uterine diagnosis.

RESULTS

A diagnosis of absent uterus was made prior to exposure to exogenous oestrogen in 22/25 (88%) of subjects with primary hypogonadism including 14/14 females with normal karyotype and 8/11 females with Turner syndrome.

CONCLUSIONS

Oestrogen deficiency is a possible explanation for most subjects being reported as having Mullerian agenesis in association with Turner syndrome or primary ovarian insufficiency. In the presence of oestrogen deficiency, no conclusion can be made about the status of the uterus until adequate exposure to exogenous oestrogen has been completed and we suggest reassessment of the uterus when full adult dose has been reached towards the end of induction of puberty.

Aging of the musculoskeletal system: How the loss of estrogen impacts muscle strength

Skeletal muscle weakness occurs with aging and in females this is compounded by the loss of estrogen with ovarian failure. Estrogen deficiency mediates decrements in muscle strength from both inadequate preservation of skeletal muscle mass and decrements in the quality of the remaining skeletal muscle. Processes and components of skeletal muscle that are affected by estrogens are beginning to be identified. This review focuses on mechanisms that contribute to the loss of muscle force generation when estrogen is low in females, and conversely the maintenance of strength by estrogen. Evidence is accumulating that estrogen deficiency induces apoptosis in skeletal muscle contributing to loss of mass and thus strength. Estrogen sensitive processes that affect quality, i.e., force generating capacity of muscle, include myosin phosphorylation and satellite cell function. Further detailing these mechanisms and identifying additional mechanisms that underlie estrogenic effects on skeletal muscle is important foundation for the design of therapeutic strategies to minimize skeletal muscle pathologies, such as sarcopenia and dynapenia.

Estrogen Modulates Cartilage and Subchondral Bone Remodeling in an Ovariectomized Rat Model of Postmenopausal Osteoarthritis

BACKGROUND Estrogen levels regulate changes in osteoarthritis (OA) by inhibiting degradation of the extracellular matrix. Recent in vitro studies have also shown the role of microRNA-140-5p (miR-140-5p). This study aimed to investigate the role of estrogen deficiency, selective modulation of expression of the estrogen receptor (ER), and expression of miR-140-5p in cartilage and subchondral bone remodeling in an ovariectomized rat model of postmenopausal OA. MATERIAL AND METHODS Female Sprague-Dawley rats included two model groups, ovariectomized (OVX) rats and rats with destabilization of the medial meniscus (DMM) rats. Two months after surgery, estrogen levels were measured by the enzyme-linked immunosorbent assay (ELISA). Three-dimensional (3D) micro-computed tomography (micro-CT) was used to image the knee joints. Rats were treated with subcutaneous injection of estrogen (E2) or the selective estrogen receptor modulator (SERM), raloxifene (RAL), for one month. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-140-5p in serum, and histology of the knee joint cartilage and bone was performed. RESULTS In the ovariectomized rat model of OA, estrogen therapy reduced the degree of cartilaginous degeneration, while treatment with raloxifene showed no significant effect. Expression levels of miR-140-5p in the OA model group were significantly lower than the control group. Micro-CT showed that in the model group, anterior cruciate ligament dislocation and subchondral bone density were significantly reduced. CONCLUSIONS In an ovariectomized rat model of postmenopausal OA, estrogen deficiency resulted in resorption of subchondral bone and degeneration of articular cartilage.

Exercise training improves vascular reactivity in ovariectomized rats subjected to myocardial infarction

The aim of this study was to evaluate the effects of exercise training (ET) on the aortic vascular reactivity of ovariectomized and infarcted rats. The animals were divided into 5 groups: Control, Ovariectomized + SHAM sedentary (OVX+SHAMSED), OVX+SHAM and ET (OVX+SHAMET), OVX + Myocardial Infarction sedentary (OVX+MISED), and OVX + MI and ET (OVX+MIET). ET protocol (60 minutes/day, 5x/week) in a motorized treadmill began 15 days after MI and lasted 8 weeks. The endothelium-dependent and endothelium-independent vascular reactivity were evaluated as well as the role of the reactive oxygen species (ROS). Superoxide and nitric oxide (NO) production were analyzed in situ using DHE and DAF-2 fluorescence, respectively. The expression of gp91phox and of the antioxidant enzymes were evaluated by western blotting in the thoracic aorta samples. MI promoted a significant increase in the contractile response and impaired endothelium-mediated relaxation. However, ET prevented the impairment in the vascular reactivity in MI animals. In addition, the protein expression of gp91phox and superoxide production increased and the NO production decreased in the OVX+MISED group but not in the OVX+MIET group. Therefore, ET improves vascular reactivity in MI ovariectomized rats by preventing the increase in the expression of gp91phox and the decrease in the antioxidant enzymes, resulting in a normal ROS and NO production. Thus, ET can be an effective therapeutic strategy for improving the MI-induced vascular alterations in estrogen deficiency condition.