Association between dietary phytoestrogen intake and bone mineral density varied with estrogen receptor alpha gene polymorphisms in southern Chinese postmenopausal women

Polyphenols as potential preventers of osteoporosis: A comprehensive review on antioxidant and anti-inflammatory effects, molecular mechanisms, and signal pathways in bone metabolism

Osteoporosis (OP) is a skeletal disorder characterized by decreased bone density, alterations in bone microstructure, and increased damage to the bones. As the population ages and life expectancy increases, OP has become a global epidemic, drawing attention from scientists and doctors. Because of polyphenols have favorable antioxidant and anti-allergy effects, which are regarded as potential methods to prevent angiocardipathy and OP. Polyphenols offer a promising approach to preventing and treating OP by affecting bone metabolism, reducing bone resolution, maintaining bone density, and lowering the differentiation level of osteoclasts (OC). There are multiple ways in which polyphenols affect bone metabolism. This article provides an overview of how polyphenols inhibit oxidative stress, exert antibacterial effects, and prevent the occurrence of OP. Furthermore, we will explore the regulatory mechanisms and signaling pathways implicated in this process.

Anti-osteoporosis effects of mammalian lignans and their precursors from flaxseed and safflower seed using zebrafish model

Secoisolariciresinol diglucoside (SDG) and tracheloside (TCL) are the main lignan components of flaxseed cake and safflower seed cake, which are by-products of oil extraction. Both SDG and TCL are metabolized into mammalian lignan enterolactone (EL) with the involvement of intestinal bacteria. In this research, we evaluated the anti-osteoporosis effects of SDG and the in vivo metabolites EL and enterodiol (ED) prepared in our previous work, as well as the newly isolated chemical constituents from safflower seed, including TCL, the lactone ring opening product of TCL (OTCL) and two alkaloids on the alloxan-induced zebrafish model. All the compounds showed significant anti-osteoporosis effects at 80 µM, with p < 0.05 for EL and p < 0.001 for other compounds compared with the model. SDG and TCL showed the most significant and concentration-dependent effects, with p < 0.001 compared with model at 20 µM. The alkaloids, N-coumaroylserotonin glucoside and N-feruloylserotonin glucoside, also showed anti-osteoporosis at 20 µM with p < 0.01, whereas EL, ED, and OTCL showed no significant effects. Quantitative real-time polymerase chain reaction revealed that SDG and TCL upregulated the expression of osteogenic genes Runx2, SP7, OPG, Col1a1a, Alp, ON, OPN, and OCN in alloxan-treated zebrafish. The in vivo metabolite of lignans, EL, showed significant anti-inflammatory effect (p < 0.01) at 20 µM, which might also help to combat osteoporosis and other complications caused by excessive immune response in the body. The results provided scientific data for using the oil extraction by-products as sources of anti-osteoporosis compounds. PRACTICAL APPLICATION: This study found that lignans in flaxseed cake and safflower seed cake exhibited anti-osteoporosis effects by upregulating the expression of osteogenic genes, making the oil extraction by-products sources of anti-osteoporosis compounds.

Dietary Assessment Methods to Estimate (Poly)phenol Intake in Epidemiological Studies: A Systematic Review

Nutritional epidemiological studies have frequently reported associations between higher (poly)phenol intake and a decrease in the risk or incidence of noncommunicable diseases. However, the assessment methods that have been used to quantify the intakes of these compounds in large-population samples are highly variable. This systematic review aims to characterize the methods used to assess dietary (poly)phenol intake in observational studies, report the validation status of the methods, and give recommendations on method selection and data reporting. Three databases were searched for publications that have used dietary assessment methods to measure (poly)phenol intake and 549 eligible full texts were identified. Food-frequency questionnaires were found to be the most commonly used tool to assess dietary (poly)phenol intake (73%). Published data from peer-reviewed journals were the major source of (poly)phenol content data (25%). An increasing number of studies used open-access databases such as Phenol-Explorer and USDA databases on flavonoid content since their inception, which accounted for 11% and 23% of the data sources, respectively. Only 16% of the studies reported a method that had been validated for measuring the target (poly)phenols. For future research we recommend: 1) selecting a validated dietary assessment tool according to the target compounds and target period of measurement; 2) applying and combining comprehensive (poly)phenol content databases such as USDA and Phenol-Explorer; 3) detailing the methods used to assess (poly)phenol intake, including dietary assessment method, (poly)phenol content data source; 4) follow the Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut) framework; and 5) complementing dietary intake assessment based on questionnaires with measurement of (poly)phenols in biofluids using appropriate and validated analytical methods.

Estimation and projection about the standardized prevalence of osteoporosis in mainland China

We performed a systematic analysis of the standardized prevalence of osteoporosis in mainland China from 1990 to 2050.

INTRODUCTION

Osteoporosis is the most common bone disease. We aimed to investigate the standardized prevalence of osteoporosis in mainland China at the national and regional levels, with projections until 2050.

METHODS

A comprehensive literature search was performed in PubMed, EMBASE, Cochrane Library, CNKI, Wanfang, and CBM-SinoMed. We constructed resample sets to calculate the standardized prevalence in each study. Multilevel mixed-effects logistic regression was used to estimate the age-specific and sex-specific prevalence. The United Nations Population Division (UNPD) data and regional population data from the fifth and sixth censuses in mainland China were used to estimate and project the national and regional prevalence of osteoporosis.

RESULTS

The standardized prevalence of osteoporosis ranged from 5.04% (2.12~11.34%) to 7.46% (3.13~16.32%) in males aged ≥ 50 years and from 26.28% (15.38~40.40%) to 39.19% (25.74~53.95%) in females aged ≥ 50 years from 1990 to 2050. Moreover, we did not find a significant difference in the standardized prevalence among three geographic regions (Central China, West China, and East China).

CONCLUSION

We found that osteoporosis is a serious public health challenge in mainland China. The findings in our study add insight into the epidemiology of osteoporosis and would be beneficial for the prevention and treatment of osteoporosis in mainland China.

Estrogenic properties of coumarins and meroterpene from the fruits of Cullen corylifolium: Experimental and computational studies

Coumarins and meroterpene from the fruits of Cullen corylifolium were evaluated for their ability to bind and activate human estrogen receptor α (hERα) by a combination of in vitro studies and molecular dynamics simulations. The recombinant hERα ligand binding domain (hERα-LBD) was produced in BL21 (DE3)pLysS and the fluorescence polarization (FP) assay was performed to determine the binding affinities of coumarins and meroterpene with receptor protein. These compounds displayed distinct binding potency toward hERα-LBD, generally increased with their increasing molecular length and Connolly solvent-excluded volume (CSEV). In an estrogen response element-luciferase (ERE-Luc) reporter gene assay, coumarins and meroterpene acted as agonists of human estrogen receptor α. Subsequently, molecular docking was conducted to elucidate the molecular mechanism behind their agonistic activities. Coumarins and meroterpene adopted an agonist conformation within the cavity of hERα-LBD. The hydrophobic and hydrogen-bonding interactions were dominant forces to stabilize their binding. The structure-activity relationship analysis suggested that the presence of hydroxyl groups and prenyl group were crucial for possessing estrogenic activities. Comparison of the calculated binding energies with the determined binding affinities yielded a good correlation (R² = 0.9727). In conclusion, molecular modeling techniques can potentially be applied for in silico screening of selective estrogen receptor modulators (SERMs) from undescribed compounds.

Identification of aberrantly expressed long non-coding RNAs in postmenopausal osteoporosis

Postmenopausal osteoporosis (PMOP) is a common skeletal disorder in postmenopausal women. The present study aimed to identify the key long non‑coding RNAs (lncRNAs) in PMOP through RNA sequencing. RNA sequencing was performed to obtain the expression profile of lncRNAs and mRNAs in blood samples of patients with PMOP and normal controls (NCs). Following the identification of differentially expressed mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs), the DElncRNA-DEmRNA co‑expression network was constructed. A search was performed for the DEGs transcribed within a 100‑kb window upstream or downstream of DElncRNAs, which served as nearby DEmRNAs of DElncRNAs. Functional annotation of the DEmRNAs co‑expressed with DElncRNAs was performed. The GSE56815 dataset was used to verify the expression of selected DEmRNAs and DElncRNAs. Three blood samples from patients with PMOP and two blood samples from NCs were used for RNA sequencing. Compared with the NC group, a total of 185 DEmRNAs and 51 DElncRNAs were obtained in PMOP. A total of 3,057 co‑expression DElncRNA‑DEmRNA pairs and 97 DElncRNA‑nearby DEmRNA pairs were obtained. Six DEmRNAs [diacylglycerol O‑acyltransferase 2, potassium voltage‑gated channel subfamily S member 1, peptidase inhibitor 3, secretory leukocyte peptidase inhibitor, galectin‑related protein and alkaline phosphatase, liver/bone/kidney (ALPL)] were nearby co‑expressed genes of four DElncRNAs, including LOC105376834, LOC101929866, LOC105374771 and LOC100506113. Three PMOP-associated DEmRNAs, including ALPL, suppressor of cytokine signaling 3 and adrenomedullin, were co‑expressed with the hub DElncRNAs (LINC00963, LOC105378415, LOC105377067, HCG27, LOC101928143 and LINC01094) of the positively and negatively co‑expressed DElncRNA‑DEmRNA interaction network. The expression of selected DEmRNAs and DElncRNAs was consistent with the RNA‑sequencing results. In conclusion, the present study identified the key DEmRNAs and DElncRNAs in PMOP, which may provide clues for understanding the mechanism and developing novel biomarkers for PMOP.

Risks and benefits related to alimentary exposure to xenoestrogens

Xenoestrogens are widely diffused in the environment and in food, thus a large portion of human population worldwide is exposed to them. Among alimentary xenoestrogens, phytoestrogens (PhyEs) are increasingly being consumed because of their potential health benefits, although there are also important risks associated to their ingestion. Furthermore, other xenoestrogens that may be present in food are represented by other chemicals possessing estrogenic activities, that are commonly defined as endocrine disrupting chemicals (EDCs). EDCs pose a serious health concern since they may cause a wide range of health problems, starting from pre-birth till adult lifelong exposure. We herein provide an overview of the main classes of xenoestrogens, which are classified on the basis of their origin, their structures and their occurrence in the food chain. Furthermore, their either beneficial or toxic effects on human health are discussed in this review.