Osteoprotective Roles of Green Tea Catechins

The potential protective effect of Camellia Sinensis in mitigating monosodium glutamate-induced neurotoxicity: biochemical and histological study in male albino rats

Monosodium glutamate (MSG) is the sodium compound derived from glutamic acid. Excessive daily ingestion of MSG leads to elevated amounts of glutamic acid in the bloodstream, which can be detrimental to brain structures. Camellia sinensis, often known as green tea (GT), is a rich source of essential hexogen antioxidants that are necessary for the body. Thirty-two adult male albino rats were divided into four groups (n = 8). Group 1 served as a control -ve group. Group 2 was given GT (1.5 ml/rat/day). Group 3 was given MSG (600 mg/kg/day). Group 4 was given MSG (600 mg/kg/day) and GT (1.5 ml/rat/day). All treatments were given orally for 28 days. MSG administration resulted in significant neurotoxicity in rats that was revealed by the significant reduction of serum concentration of glutathione peroxidase (GPx) and nitric oxide (NO), and the significant elevation of total antioxidant capacity (TAC) accompanied by the significant reduction of levels of serum monoamines (dopamine, serotonin, and norepinephrine) and histological changes in the hippocampus area CA1, dentate gyrus, and cerebellar cortex and positive immunohistochemical staining of glial fibrillary acidic proteins (GFAP) and calretinin. Administration of GT with MSG counteracted the MSG-mediated oxidative stress by significantly increasing serum concentrations of GPX and NO and significantly decreasing concentrations of TAC. Furthermore, GT significantly increased levels of serum monoamines (dopamine, serotonin, and norepinephrine). Moreover, it ameliorated the histological changes, GFAP, and calretinin immunostaining in brain tissues. It is envisaged that GT will serve as a viable protective choice for the inclusion of the neurotoxicity treatment procedure.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Pleiotropic effects of trisomy and pharmacologic modulation on structural, functional, molecular, and genetic systems in a Down syndrome mouse model

Down syndrome (DS) is characterized by skeletal and brain structural malformations, cognitive impairment, altered hippocampal metabolite concentration and gene expression imbalance. These alterations were usually investigated separately, and the potential rescuing effects of green tea extracts enriched in epigallocatechin-3-gallate (GTE-EGCG) provided disparate results due to different experimental conditions. We overcame these limitations by conducting the first longitudinal controlled experiment evaluating genotype and GTE-EGCG prenatal chronic treatment effects before and after treatment discontinuation. Our findings revealed that the Ts65Dn mouse model reflected the pleiotropic nature of DS, exhibiting brachycephalic skull, ventriculomegaly, neurodevelopmental delay, hyperactivity, and impaired memory robustness with altered hippocampal metabolite concentration and gene expression. GTE-EGCG treatment modulated most systems simultaneously but did not rescue DS phenotypes. On the contrary, the treatment exacerbated trisomic phenotypes including body weight, tibia microarchitecture, neurodevelopment, adult cognition, and metabolite concentration, not supporting the therapeutic use of GTE-EGCG as a prenatal chronic treatment. Our results highlight the importance of longitudinal experiments assessing the co-modulation of multiple systems throughout development when characterizing preclinical models in complex disorders and evaluating the pleiotropic effects and general safety of pharmacological treatments.

Planar catechin increases bone mass by regulating differentiation of osteoclasts in mice

OBJECTIVES

While catechins have been reported to exhibit potential to benefit osteoporosis patients, the effects of planar catechin (PCat), synthesized during the development of drugs for Alzheimer's disease, have not been clearly elucidated. Here, we examined the effects of PCat on mouse bone metabolism both in vivo and in vitro.

METHODS

Six week old female mice were orally administered PCat (30 mg/kg) every other day for four weeks, and their femurs were analyzed using micro-computed tomography imaging. Osteoclasts and osteoblasts were collected from mice and cultured with PCat. Subsequently, osteoclast formation and differentiation and osteoblast differentiation were observed.

RESULTS

Mice orally administered PCat displayed significantly increased femur bone mass compared to the control group. Quantitative polymerase chain reaction findings indicated that PCat addition to osteoclast progenitor cultures suppressed osteoclast formation and decreased osteoclast marker expression without affecting the proliferative potential of the osteoclast progenitor cells. Addition of PCat to osteoblast cultures increased osteoblast marker expression.

CONCLUSIONS

PCat inhibits osteoclast differentiation and promotes osteoblast differentiation, resulting in increased bone mass in mice. These results suggest that PCat administration is a promising treatment option for conditions associated with bone loss, including osteoporosis.

Isolation of Pro-Osteogenic Compounds from Euptelea polyandra That Reciprocally Regulate Osteoblast and Osteoclast Differentiation

Plants contain a large number of small-molecule compounds that are useful for targeting human health and in drug discovery. Healthy bone metabolism depends on the balance between bone-forming osteoblast activity and bone-resorbing osteoclast activity. In an ongoing study searching for 22 plant extracts effective against osteoporosis, we found that the crude extract of Euptelea polyandra Sieb. et Zucc (E. polyandra) had osteogenic bioactivity. In this study, we isolated two compounds, isoquercitrin (1) and astragalin (2), responsible for osteogenic bioactivity in osteoblastic MC3T3-E1 cells from the leaf of E. polyandra using column chromatography and the spectroscopic technique. This is the first report to isolate astragalin from E. polyandra. Compounds (1) and (2) promoted osteoblast differentiation by increasing alkaline phosphatase (ALP) activity and alizarin red S stain-positive calcium deposition, while simultaneously suppressing tartrate-resistant acid phosphatase (TRAP)-positive osteoclast differentiation in RAW264.7 cells at non-cytotoxic concentrations. Isoquercitrin (1) and astragalin (2) increased the expression of osteoblastic differentiation genes, Osterix, ALP, and Osteoprotegerin in the MC3T3-E1 cells, while suppressing osteoclast differentiation genes, TRAP, Cathepsin K, and MMP 9 in the RAW264.7 cells. These compounds may be ideal targets for the treatment of osteoporosis due to their dual function of promoting bone formation and inhibiting bone resorption.

N-Acetyl-l-cysteine-Derived Carbonized Polymer Dots with ROS Scavenging via Keap1-Nrf2 Pathway Regulate Alveolar Bone Homeostasis in Periodontitis

Periodontitis is a type of chronic inflammatory oral disease characterized by the destruction of periodontal connective tissue and progressive alveolar bone resorption. As oxidative stress is the key cause of periodontitis in the early periodontal microenvironment, antioxidative therapy has been considered a viable treatment for periodontitis. However, more stable and effective reactive oxygen species (ROS)-scavenging nanomedicines are still highly needed due to the instability of traditional antioxidants. Herein, a new type of N-acetyl-l-cysteine (NAC)-derived red fluorescent carbonized polymer dots (CPDs) has been synthesized with excellent biocompatibility, which can serve as an extracellular antioxidant to scavenge ROS effectively. Moreover, NAC-CPDs can promote osteogenic differentiation in human periodontal ligament cells (hPDLCs) under H2 O2 stimulation. In addition, NAC-CPDs are capable of targeted accumulation in alveolar bone in vivo, reducing the level of alveolar bone resorption in periodontitis mice, as well as performing fluorescence imaging in vitro and in vivo. In terms of mechanism, NAC-CPDs may regulate redox homeostasis and promote bone formation in the periodontitis microenvironment by modulating the kelch-like ECH-associated protein l (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. This study provides a new strategy for the application of CPDs theranostic nanoplatform for periodontitis.

Maternal Exposure to Red Rooibos Does Not Alter Bone Development in Male or Female Sprague-Dawley Rat Offspring

Maternal diet during pregnancy and/or throughout lactation provides a potential opportunity for nutritional programming of offspring bone development. Objectives of this study were to determine whether maternal consumption of red rooibos (RR) throughout pregnancy and lactation improved bone mineral density (BMD), bone structure, and bone strength in offspring and to determine potential sex-specific responses. Female Sprague-Dawley rats were randomly assigned to control water or RR in water (2600 mg/kg body weight/d) from prepregnancy through to the end of lactation. At weaning, offspring were fed AIN-93G diet until age 3 mo. Longitudinal assessment of the tibia demonstrated that maternal exposure to RR did not alter the trajectory of BMD or bone structure in male or female offspring compared with sex-specific controls at age 1, 2, or 3 mo or bone strength at age 3 mo. In conclusion, maternal exposure to RR did not program bone development in male or female offspring.

Epicatechin gallate promotes vascularization in co-culture of human osteoblasts and outgrowth endothelial cells

Prevascularization is crucial for the survival of tissue-engineered bone and further bone repair/regeneration. Since epicatechin gallate (ECG), the most abundant flavanol in green tea, shows potential beneficial effects on endothelial cells and bone cells, we decided to investigate whether it promotes vascularization/angiogenesis and osteogenesis using a co-culture system containing human primary osteoblasts (POBs) and outgrowth endothelial cells (OECs). We found that treatment with ECG (1) significantly enhanced microvessel formation in co-culture of POB and OECs, (2) improved cell viability/proliferation and the angiogenic/osteogenic capacities of OEC/POBs, (3) significantly increased the levels of E-selectin, IL-6, TNF-α, IFN-γ, VEGF, and PDGF-BB in co-cultures of POB and OEC, and (4) upregulated HIF-1α, HIF-2α, NF-κB, iNOS, GLUT1, VEGF, and Ang1/2 but downregulated PHD1 in monocultures of OEC or POB. Our findings demonstrate that ECG promotes angiogenesis and osteogenesis (probably via HIF signaling) in co-cultures of OECs and POBs. ECG thus has potential applications in the promotion of angiogenesis/vascularization in many tissue constructs including those of bone.

Oxidative Stress and Natural Antioxidants in Osteoporosis: Novel Preventive and Therapeutic Approaches

This review reports in detail the cellular and molecular mechanisms which regulate the bone remodeling process in relation to oxidative stress (OS), inflammatory factors, and estrogen deficiency. OS is considered an important pathogenic factor of osteoporosis, inducing osteocyte apoptosis and varying levels of specific factors, such as receptor activator κB ligand (RANKL), sclerostin, and, according to recent evidence, fibroblast growth factor 23, with consequent impairment of bone remodeling and high bone resorption. Bone loss increases the risk of fragility fractures, and the most commonly used treatments are antiresorptive drugs, followed by anabolic drugs or those with a double effect. In addition, recent data show that natural antioxidants contained in the diet are efficient in preventing and reducing the negative effects of OS on bone remodeling and osteocytes through the involvement of sirtuin type 1 enzyme. Indeed, osteocytes and some of their molecular factors are considered potential biological targets on which antioxidants can act to prevent and reduce bone loss, as well as to promote bone anabolic and regenerative processes by restoring physiological bone remodeling. Several data suggest including antioxidants in novel therapeutic approaches to develop better management strategies for the prevention and treatment of osteoporosis and OS-related bone diseases. In particular, anthocyanins, as well as resveratrol, lycopene, oleuropein, some vitamins, and thiol antioxidants, could have protective and therapeutic anti-osteoporotic effects.

Regulatory Effects and Mechanism of Action of Green Tea Polyphenols on Osteogenesis and Adipogenesis in Human Adipose Tissue-Derived Stem Cells

We previously showed that green tea polyphenols (GTPs) exert antiadipogenic effects on preadipocyte proliferation. Here, we investigated the regulatory effects of GTPs on osteogenesis and adipogenesis during early differentiation of human adipose tissue-derived stem cells (hADSC). Adipogenesis of hADSCs was determined by oil-red-O staining and triglycerides synthesis measurement. Osteoporosis of hADSC was measured using alkaline phosphatase assays and intracellular calcium levels. Immunofluorescence staining and qRT-PCR were used to detect PPARγ-CEBPA regulated adipogenic pathway regulated by PPAR-CEBPA and the osteogenic pathway mediated by RUNX2-BMP2. We found that GTPs treatment significantly decreased lipid accumulation and cellular triglyceride synthesis in mature adipocytes and attenuated pioglitazone-induced adipogenesis in a dose-dependent manner. GTPs downregulated protein and mRNA expression of Pparγ and attenuated pioglitazone-stimulated-Cebpa expression. GTPs treatment significantly enhanced hADSCs differentiation into osteoblasts compared to control and pioglitazone-treated cells. GTPs upregulated RunX2 and Bmp2 proteins and mRNA expression compared to control and significantly attenuated decreased RunX2 and Bmp2 mRNA expression by pioglitazone. In conclusion, our data demonstrates GTPs possesses great ability to facilitate osteogenesis and simultaneously inhibits hADSC differentiation into adipogenic lineage by upregulating the RUNX2-BMP2 mediated osteogenic pathway and suppressing PPARγ-induced signaling of adipogenesis. These findings highlight GTPs' potential to combat osteoporosis associated with obesity.

Ablation of Discoidin Domain Receptor 1 Provokes an Osteopenic Phenotype by Regulating Osteoblast/Osteocyte Autophagy and Apoptosis

Discoidin domain receptor 1 (DDR1) is a collagen receptor that belongs to the receptor tyrosine kinase family. We have previously shown that DDR1 plays a crucial role during bone development, resulting in dwarfism and a short stature in osteoblast-specific knockout mice (OKO mice). However, the detailed pathophysiological effects of DDR1 on bone development throughout adulthood have remained unclear. This study aims to identify how DDR1 regulates osteoblast and osteocyte functions in vivo and in vitro during bone development in adulthood. The metabolic changes in bone tissues were analyzed using Micro-CT and immunohistochemistry staining (IHC) in vivo; the role of DDR1 in regulating osteoblasts was examined in MC3T3-E1 cells in vitro. The Micro-CT analysis results demonstrated that OKO mice showed a 10% reduction in bone-related parameters from 10 to 14 weeks old and a significant reduction in cortical thickness and diameter compared with flox/flox control mice (FF) mice. These results indicated that DDR1 knockout in OKO mice exhibiting significant bone loss provokes an osteopenic phenotype. The IHC staining revealed a significant decrease in osteogenesis-related genes, including RUNX2, osteocalcin, and osterix. We noted that DDR1 knockout significantly induced osteoblast/osteocyte apoptosis and markedly decreased autophagy activity in vivo. Additionally, the results of the gain- and loss-of-function of the DDR1 assay in MC3T3-E1 cells indicated that DDR1 can regulate the osteoblast differentiation through activating autophagy by regulating the phosphorylation of the mechanistic target of rapamycin (p-mTOR), light chain 3 (LC3), and beclin-1. In conclusion, our study highlights that the ablation of DDR1 results in cancellous bone loss by regulating osteoblast/osteocyte autophagy. These results suggest that DDR1 can act as a potential therapeutic target for managing cancellous bone loss.

Polyphenols: Bioavailability, Microbiome Interactions and Cellular Effects on Health in Humans and Animals

Polyphenolic compounds have a variety of functions in plants including protecting them from a range of abiotic and biotic stresses such as pathogenic infections, ionising radiation and as signalling molecules. They are common constituents of human and animal diets, undergoing extensive metabolism by gut microbiota in many cases prior to entering circulation. They are linked to a range of positive health effects, including anti-oxidant, anti-inflammatory, antibiotic and disease-specific activities but the relationships between polyphenol bio-transformation products and their interactions in vivo are less well understood. Here we review the state of knowledge in this area, specifically what happens to dietary polyphenols after ingestion and how this is linked to health effects in humans and animals; paying particular attention to farm animals and pigs. We focus on the chemical transformation of polyphenols after ingestion, through microbial transformation, conjugation, absorption, entry into circulation and uptake by cells and tissues, focusing on recent findings in relation to bone. We review what is known about how these processes affect polyphenol bioactivity, highlighting gaps in knowledge. The implications of extending the use of polyphenols to treat specific pathogenic infections and other illnesses is explored.

Impact of High-Altitude Hypoxia on Bone Defect Repair: A Review of Molecular Mechanisms and Therapeutic Implications

Reaching areas at altitudes over 2,500–3,000 m above sea level has become increasingly common due to commerce, military deployment, tourism, and entertainment. The high-altitude environment exerts systemic effects on humans that represent a series of compensatory reactions and affects the activity of bone cells. Cellular structures closely related to oxygen-sensing produce corresponding functional changes, resulting in decreased tissue vascularization, declined repair ability of bone defects, and longer healing time. This review focuses on the impact of high-altitude hypoxia on bone defect repair and discusses the possible mechanisms related to ion channels, reactive oxygen species production, mitochondrial function, autophagy, and epigenetics. Based on the key pathogenic mechanisms, potential therapeutic strategies have also been suggested. This review contributes novel insights into the mechanisms of abnormal bone defect repair in hypoxic environments, along with therapeutic applications. We aim to provide a foundation for future targeted, personalized, and precise bone regeneration therapies according to the adaptation of patients to high altitudes.

Antiosteoporosis Studies of 20 Medicine Food Homology Plants Containing Quercetin, Rutin, and Kaempferol: TCM Characteristics, In Vivo and In Vitro Activities, Potential Mechanisms, and Food Functions

Dietary nutraceutical compounds have been evidenced as backbone for bone health in recent years. It is reported that medicine food homology (MFH) plants have multiple nutraceutical compounds. Based on our literature research, 20 MFH plants caught our attention because they contain three popular antiosteoporosis compounds simultaneously: quercetin, rutin, and kaempferol. According to traditional Chinese medicine (TCM), their characteristics including natures, flavors, attributive to meridian tropism, and efficacies were listed. The relationships between TCM efficacies, such as “heat clearing,” “tonic,” and “the interior warming,” and antiosteoporosis pharmacological actions such as antioxidant and immune regulation were discussed. The in vivo antiosteoporosis effects of the 20 MFH plants were summarized. The in vitro antiosteoporosis activities and related mechanisms of the 20 plants and quercetin, rutin, kaempferol were detailed. The TGF-β-Smad signaling, fibroblast growth factor, and Wnt/β-catenin signaling on bone formation and the RANKL signaling, NF-κB signaling, and macrophage-colony-stimulating factor on bone resorption were identified. From food point, these 20 MFH plants could be classified as condiment, vegetable, fruit, tea and related products, beverage, etc. Based on the above discussion, these 20 MFH plants could be used as daily food supplements for the prevention and treatment against osteoporosis.

Increased dosage and treatment time of Epigallocatechin-3-gallate (EGCG) negatively affects skeletal parameters in normal mice and Down syndrome mouse models

Bone abnormalities affect all individuals with Down syndrome (DS) and are linked to abnormal expression of DYRK1A, a gene found in three copies in people with DS and Ts65Dn DS model mice. Previous work in Ts65Dn male mice demonstrated that both genetic normalization of Dyrk1a and treatment with ~9 mg/kg/day Epigallocatechin-3-gallate (EGCG), the main polyphenol found in green tea and putative DYRK1A inhibitor, improved some skeletal deficits. Because EGCG treatment improved mostly trabecular skeletal deficits, we hypothesized that increasing EGCG treatment dosage and length of administration would positively affect both trabecular and cortical bone in Ts65Dn mice. Treatment of individuals with DS with green tea extract (GTE) containing EGCG also showed some weight loss in individuals with DS, and we hypothesized that weights would be affected in Ts65Dn mice after EGCG treatment. Treatment with ~20 mg/kg/day EGCG for seven weeks showed no improvements in male Ts65Dn trabecular bone and only limited improvements in cortical measures. Comparing skeletal analyses after ~20mg/kg/day EGCG treatment with previously published treatments with ~9, 50, and 200 mg/kg/day EGCG showed that increased dosage and treatment time increased cortical structural deficits leading to weaker appendicular bones in male mice. Weight was not affected by treatment in mice, except for those given a high dose of EGCG by oral gavage. These data indicate that high doses of EGCG, similar to those reported in some treatment studies of DS and other disorders, may impair long bone structure and strength. Skeletal phenotypes should be monitored when high doses of EGCG are administered therapeutically.

Protective effects of apple polyphenols on bone loss in mice with high fat diet-induced obesity

Obesity-induced inflammation can lead to an imbalance in bone formation and resorption. Our previous studies have demonstrated that apple polyphenols (AP) can reduce body weight and inflammation. But its effect...

Hepatoprotective effects of methanolic extract of green tea against Thioacetamide-Induced liver injury in Sprague Dawley rats

ETHNOPHARMACOLOGICAL RELEVANCE

Since ancient times, herbal medicines have been applied in the treatment of cancer. Tea, derivative from the dried leaves of Camellia sinensis (L.) Kuntze plant is the most popular beverage globally after water and is available in various forms. Green tea has been expansively investigated for its beneficial properties of cancer prevention and therapy. The goal of the research: The current study was conducted to evaluate the hepaprotective character of methanolic green tea extract and its mechanism of action contrary to thioacetamide (TAA)-produced liver fibrosis of Sprague Dawley rats.

MATERIALS AND METHODS

Thirty rodents were equally placed in 5 clusters including normal control, TAA group as a positive control, silymarin as standard drug control, and treatment groups consisting of high dose and a low dose Camellia sinensis. Rats in experimental clusters by mouth fed with C. sinensis at 250 mg/kg or 500 mg/kg daily for 2 months. After 60 days, all rats were sacrificed. Blood specimens were gathered for liver biochemical examination. Livers of all groups were dissected out and subjected to histopathological examination through the Hematoxylin and Eosin stain, Masson trichrome, and immunohistochemistry stains (PCNA). Liver tissue homogenate was also analyzed for antioxidant activity parameters.

RESULTS

Gross morphological examination showed a regular liver architecture in C. sinensis fed collections compared to the TAA sets. Histology of rat's liver fed with C. sinensis showed an important decrease in the liver index with hepatic cells propagation, mild cellular injury, and immunostaining showed significant down-expression of proliferating cell nuclear antigen (PCNA). TAA produced liver fibrosis through a significant increase in serum alanine transferase, aspartate aminotransferase, alkaline phosphatase, and bilirubin. Total protein and albumin also decreased in the TAA group. Moreover, the reduction of antioxidant enzyme activity including superoxide dismutase and catalase as well as the increase in malondialdehyde was detected in the TAA control group. Meanwhile, an abnormal level of liver biochemical parameters was restored closer to the normal levels in serum of the C. sinensis-fed clusters. In addition, C. sinensis fed assemblies showed elevated antioxidative enzymes activity with a reduction in malondialdehyde level comparable to the levels in silymarin-treated rats.

CONCLUSIONS

Green tea potentially inhibited the progression of liver cirrhosis, down -regulation of PCNA proliferation, prevented oxidation of hepatocytes, recovered SOD and CAT enzymes, condensed MDA and reduced cellular inflammation.

Quebecol Shows Potential to Alleviate Periodontal Tissue Damage and Promote Bone Formation in In Vitro Models

Quebecol is a polyphenolic compound initially isolated from Canadian maple syrup in 2011. Recently, our group demonstrated in a macrophage model that quebecol inhibits the secretion of pro-inflammatory cytokines and reduces the activation of the NF-κB transcription factor. In this study, we further explored the therapeutic potential of quebecol against periodontal disease, an inflammatory disorder of bacterial origin affecting tooth-supporting tissues. More specifically, the effects of this natural compound on matrix metalloproteinase (MMP) activity and macrophage secretion, as well as on the mineralization activity of osteoblasts (bone-forming cells), were investigated. Results showed that exposing lipopolysaccharide (LPS)-treated macrophages to quebecol led to a significant decrease in the secretion of MMP-8 and MMP-9. In addition, quebecol dose dependently inhibited the catalytic activity of MMP-9. Quebecol also enhanced the mineralization activity of osteoblasts. This study brought forward additional evidence to support the potential of quebecol as a nutraceutical agent against periodontitis.

Nutritional intake and bone health

Osteoporotic or fragility fractures affect one in two women and one in five men who are older than 50. These events are associated with substantial morbidity, increased mortality, and an impaired quality of life. Recommended general measures for fragility fracture prevention include a balanced diet with an optimal protein and calcium intake and vitamin D sufficiency, together with regular weight-bearing physical exercise. In this narrative Review, we discuss the role of nutrients, foods, and dietary patterns in maintaining bone health. Much of this information comes from observational studies. Bone mineral density, microstructure-estimated bone strength, and trabecular and cortical microstructure are positively associated with total protein intake. Several studies indicate that fracture risk might be lower with a higher dietary protein intake, provided that the calcium supply is sufficient. Dairy products are a valuable source of these two nutrients. Hip fracture risk appears to be lower in consumers of dairy products, particularly fermented dairy products. Consuming less than five servings per day of fruit and vegetables is associated with a higher hip fracture risk. Adherence to a Mediterranean diet or to a prudent diet is associated with a lower fracture risk. These various nutrients and dietary patterns influence gut microbiota composition or function, or both. The conclusions of this Review emphasise the importance of a balanced diet including minerals, protein, and fruit and vegetables for bone health and in the prevention of fragility fractures.

Raloxifene Ameliorates Glucosamine-Induced Insulin Resistance in Ovariectomized Rats

Osteoarthritis (OA) and osteoporosis (OP) are common among older women, especially postmenopausal women. Glucosamine (GlcN) is a common medication for OA, but it may induce insulin resistance and β-cell dysfunction, especially if ovarian hormones are lacking. Raloxifene (RLX) is a selective estrogen receptor modulator and also an OP drug. Previously, we found that estrogen could improve GlcN-induced insulin resistance in ovariectomized (OVX) rats. Here, we further hypothesized that RLX, similarly to estrogen, can ameliorate GlcN-induced insulin resistance in OVX rats. We used GlcN to induce insulin resistance in OVX rats as a model for evaluating the protective effects of RLX in vivo. We used a pancreatic β-cell line, MIN-6, to study the mechanisms underlying the effect of RLX in GlcN-induced β-cell dysfunction in vitro. Increases in fasting plasma glucose, insulin, and homeostasis model assessments of insulin resistance in OVX Sprague Dawley rats treated with GlcN were reversed by RLX treatment (n = 8 in each group). Skeletal muscle GLUT-4 increased, liver PEPCK decreased, pancreatic islet hypertrophy, and β-cell apoptosis in OVX rats treated with GlcN was ameliorated by RLX. The negative effects of GlcN on insulin secretion and cell viability in MIN-6 cells were related to the upregulation of reticulum (ER) stress-associated proteins (C/EBP homologous protein, phospho-extracellular signal-regulated kinase, phospho-c-JunN-terminal kinase), the expression of which was reduced by RLX. Pretreatment with estrogen receptor antagonists reversed the protective effects of RLX. GlcN can induce insulin resistance, β-cell dysfunction, and apoptosis in OVX rats and increase ER stress-related proteins in β-cells, whereas RLX can reverse these adverse effects. The effects of RLX act mainly through estrogen receptor α; therefore, RLX may be a candidate drug for postmenopausal women with OA and OP.

Controlled killing of human cervical cancer cells by combined action of blue light and C-doped TiO2 nanoparticles

In this study, C-doped TiO₂ nanoparticles (C-TiO₂) were prepared and tested as a photosensitizer for visible-light-driven photodynamic therapy against cervical cancer cells (HeLa). X-ray diffraction and Transmission Electron Microscopy confirmed the anatase form of nanoparticles, spherical shape, and size distribution from 5 to 15 nm. Ultraviolet-visible light spectroscopy showed that C doping of TiO₂ enhances the optical absorption in the visible light range caused by a bandgap narrowing. The photo-cytotoxic activity of C-TiO₂ was investigated in vitro against HeLa cells. The lack of dark cytotoxicity indicates good biocompatibility of C-TiO₂. In contrast, a combination with blue light significantly reduced the survival of HeLa cells: illumination only decreased cell viability by 30% (15 min of illumination, 120 µW power), and 60% when HeLa cells were preincubated with C-TiO₂. We have also confirmed blue light-induced C-TiO₂-catalyzed generation of reactive oxygen species in vitro and intracellularly. Oxidative stress triggered by C-TiO₂/blue light was the leading cause of HeLa cell death. Fluorescent labeling of treated HeLa cells showed distinct morphological changes after the C-TiO₂/blue light treatment. Unlike blue light illumination, which caused the appearance of large necrotic cells with deformed nuclei, cytoplasm swelling, and membrane blebbing, a combination of C-TiO₂/blue light leads to controlled cell death, thus providing a better outcome of local anticancer therapy.

Beneficial Effects of Green Tea Catechins on Female Reproductive Disorders: A Review

Tea is one of the most widely consumed beverages worldwide after water, and green tea accounts for 20% of the total tea consumption. The health benefits of green tea are attributed to its natural antioxidants, namely, catechins, which are phenolic compounds with diverse beneficial effects on human health. The beneficial effects of green tea and its major bioactive component, (-)-epigallocatechin-3-gallate (EGCG), on health include high antioxidative, osteoprotective, neuroprotective, anti-cancer, anti-hyperlipidemia and anti-diabetic effects. However, the review of green tea's benefits on female reproductive disorders, including polycystic ovary syndrome (PCOS), endometriosis and dysmenorrhea, remains scarce. Thus, this review summarises current knowledge on the beneficial effects of green tea catechins on selected female reproductive disorders. Green tea or its derivative, EGCG, improves endometriosis mainly through anti-angiogenic, anti-fibrotic, anti-proliferative and proapoptotic mechanisms. Moreover, green tea enhances ovulation and reduces cyst formation in PCOS while improving generalised hyperalgesia, and reduces plasma corticosterone levels and uterine contractility in dysmenorrhea. However, information on clinical trials is inadequate for translating excellent findings on green tea benefits in animal endometriosis models. Thus, future clinical intervention studies are needed to provide clear evidence of the green tea benefits with regard to these diseases.

Impact of Cigarette Smoking on the Risk of Osteoporosis in Inflammatory Bowel Diseases

Cigarette smoking constitutes one of the most important modifiable factors of osteoporosis, as well as contributes to an early death, tumors, and numerous chronic diseases. The group with an increased risk of a lower bone mineral density are patients suffering from inflammatory bowel diseases. In fact, tobacco smoke, which contains more than 7000 chemical compounds, affects bone mineral density (BMD) both directly and indirectly, as it has an impact on the RANK-RANKL-OPG pathway, intestinal microbiota composition, and calcium-phosphate balance. Constant cigarette use interferes with the production of protective mucus and inhibits the repair processes in the intestinal mucus. Nicotine as well as the other compounds of the cigarette smoke are important risk factors of the inflammatory bowel disease and osteoporosis. Additionally, cigarette smoking may decrease BMD in the IBD patients. Interestingly, it affects patients with Crohn's disease and ulcerative colitis in different ways-on the one hand it protects against ulcerative colitis, whereas on the other it increases the risk of Crohn's disease development. Nevertheless, all patients should be encouraged to cease smoking in order to decrease the risk of developing other disorders.

Intra-Articular Injection of (-)-Epigallocatechin 3-Gallate to Attenuate Articular Cartilage Degeneration by Enhancing Autophagy in a Post-Traumatic Osteoarthritis Rat Model

(-)-Epigallocatechin 3-gallate (EGCG) is the main active green tea catechin and has a wide variety of benefits for health. Post-traumatic osteoarthritis (PTOA) occurs as a consequence of joint injuries that commonly happen in the young population. In this study, we investigated the effects of EGCG on PTOA prevention by using the anterior cruciate ligament transection (ACLT)–OA model and further investigated the roles of autophagy in OA treatment. Our results showed that intra-articular injection of EGCG significantly improved the functional performances and decreased cartilage degradation. EGCG treatment attenuated the inflammation on synovial tissue and cartilage through less immunostained cyclooxygenase-2 and matrix metalloproteinase-13. We further noted EGCG may modulate the chondrocyte apoptosis by activation of the cytoprotective autophagy through reducing the expression of the mTOR and enhancing the expression of microtubule-associated protein light chain 3, beclin-1, and p62. In conclusion, intra-articular injection of EGCG after ACL injury inhibited the joint inflammation and cartilage degradation, thereby increasing joint function. EGCG treatment also reduced the chondrocyte apoptosis, possibly by activating autophagy. These findings suggested that EGCG may be a potential disease-modifying drug for preventing OA progression.