Synergistic effects of green tea polyphenols and alphacalcidol on chronic inflammation-induced bone loss in female rats

Evaluating the ameliorative effect of nano bis-demethoxy curcumin analog against extrapulmonary toxicity in rat induced by inhaled multi-walled carbon nanotube

Carbon nanotubes (CNTs) exposure in human beings through inhalation may affect pulmonary organs and extrapulmonary organs including liver, kidney, brain, spleen, etc. The toxic effects developed as the result of CNTs exposure made us to explore the beneficial effect of nano bis-demethoxy curcumin analog (NBDMCA) towards multi-walled carbon nanotubes (MWCNTs)-induced toxicity in extrapulmonary organs. The current study described the ameliorative effect of NBDMCA against the toxic effects developed by inhaled MWCNTs in the extrapulmonary organs. The rats are exposed to the fixed aerosol concentration of 5 mg/m3 maintained in inhalation exposure chambers MWCNTs for 15 days as per OECD guidelines. After the exposure with MWCNTs, the animals were treated with NBDMCA (5 mg/kg body weight) with different dose frequencies, i.e., 2 doses per week for 1, 2, and 4 weeks. After treatment duration, the blood was drawn from retro-orbital vein and subjected to biochemical and cytokine analysis. Further the animals were euthanized, and the sample tissues were collected and performed oxidative stress and histopathology. The study results revealed that the intravenous administration of NBDMCA suppresses the extrapulmonary toxicity induced by MWCNTs, i.e., annulling the clinical changes and oxidative stress in various extrapulmonary organs at low doses of NBDMCA, evidenced its antioxidant efficacy. Moreover, use of increased doses provides better reduction in toxic symptoms with negligible side effects confirming the dose-dependent efficacy of NBDMCA. Overall, we suggested that NBDMCA may materialize into an effective compound for the reduction of MWCNTs-induced toxicity.

Epigallocatechin gallate attenuates tumor necrosis factor (TNF)-α-induced inhibition of osteoblastic differentiation by up-regulating lncRNA TUG1 in osteoporosis

Promoting osteoblast proliferation and differentiation contributes to the prevention and clinical treatment of osteoporosis. This study was to investigate the effect and mechanism of epigallocatechin gallate (EGCG) on tumor necrosis factor (TNF)-α-caused inhibition of osteoblastic differentiation. First, we cultured mouse embryo osteoblast precursor cells (MC3T3-E1) and induced by TNF-α (0, 2.5, 5, 10 ng/mL). The results revealed that TNF-α significantly inhibited the proliferation, ALP activity and mineralized nodule formation of MC3T3-E1 cells and promoted apoptosis. However, EGCG pretreatment significantly alleviated the inhibitory effect of TNF-α on MC3T3-E1. In addition, TNF-α significantly downregulated the expression of lncRNA TUG1 in MC3T3-E1, while EGCG upregulated the expression of lncRNA TUG1. After overexpression of lncRNA TUG1 in TNF-α-induced MC3T3-E1 cells, it could show similar effects as EGCG. However, interference with lncRNA TUG1 expression diminished the protective effect of EGCG on TNF-α-induced MC3T3-E1 cells. Finally, we found that EGCG inhibited TNF-α-induced activation of the Hippo/YAP signaling pathway, and that low expression of lncRNA TUG1 suppressed this effect. In conclusion, EGCG could suppress Hippo/YAP pathway activity by up-regulating lncRNA TUG1, ultimately improving TNF-α-caused inhibition of osteoblastic differentiation.

Osteoprotective Roles of Green Tea Catechins

Osteoporosis is the second most common disease only secondary to cardiovascular disease, with the risk of fracture increasing with age. Osteoporosis is caused by an imbalance between osteoblastogenesis and osteoclastogenesis processes. Osteoclastogenesis may be enhanced, osteoblastogenesis may be reduced, or both may be evident. Inflammation and high reactive oxygen enhance osteoclastogenesis while reducing osteoblastogenesis by inducing osteoblast apoptosis and suppressing osteoblastic proliferation and differentiation. Catechins, the main polyphenols found in green tea with potent anti-oxidant and anti-inflammatory properties, can counteract the deleterious effects of the imbalance of osteoblastogenesis and osteoclastogenesis caused by osteoporosis. Green tea catechins can attenuate osteoclastogenesis by enhancing apoptosis of osteoclasts, hampering osteoclastogenesis, and prohibiting bone resorption in vitro. Catechin effects can be directly exerted on pre-osteoclasts/osteoclasts or indirectly exerted via the modulation of mesenchymal stem cells (MSCs)/stromal cell regulation of pre-osteoclasts through activation of the nuclear factor kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. Catechins also can enhance osteoblastogenesis by enhancing osteogenic differentiation of MSCs and increasing osteoblastic survival, proliferation, differentiation, and mineralization. The in vitro effects of catechins on osteogenesis have been confirmed in several animal models, as well as in epidemiological observational studies on human subjects. Even though randomized control trials have not shown that catechins provide anti-fracture efficacy, safety data in the trials are promising. A large-scale, placebo-controlled, long-term randomized trial with a tea regimen intervention of optimal duration is required to determine anti-fracture efficacy.

Green Tea Catechin (-)-Epigallocatechin-3-Gallate (EGCG) Facilitates Fracture Healing

Green tea drinking can ameliorate postmenopausal osteoporosis by increasing the bone mineral density. (-)-Epigallocatechin-3-gallate (EGCG), the abundant and active compound of tea catechin, was proven to be able to reduce bone loss and ameliorate microarchitecture in female ovariectomized rats. EGCG can also enhance the osteogenic differentiation of murine bone marrow mesenchymal stem cells and inhibit the osteoclastogenesis in RAW264.7 cells by modulation of the receptor activator of nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegrin (OPG) (RANK/RANKL/OPG) pathway. Our previous study also found that EGCG can promote bone defect healing in the distal femur partially via bone morphogenetic protein-2 (BMP-2). Considering the osteoinduction property of BMP-2, we hypothesized that EGCG could accelerate the bone healing process with an increased expression of BMP-2. In this manuscript, we studied whether the local use of EGCG can facilitate tibial fracture healing. Fifty-six 4-month-old rats were randomly assigned to two groups after being weight-matched: a control group with vehicle treatment (Ctrl) and a study group with 10 µmol/L, 40 µL, EGCG treatment (EGCG). Two days after the operation, the rats were treated daily with EGCG or vehicle by percutaneous local injection for 2 weeks. The application of EGCG enhanced callus formation by increasing the bone volume and subsequently improved the mechanical properties of the tibial bone, including the maximal load, break load, stiffness, and Young’s modulus. The results of the histology and BMP-2 immunohistochemistry staining showed that EGCG treatment accelerated the bone matrix formation and produced a stronger expression of BMP-2. Taken together, this study for the first time demonstrated that local treatment of EGCG can accelerate the fracture healing process at least partly via BMP-2.

Myrtus Polyphenols, from Antioxidants to Anti-Inflammatory Molecules: Exploring a Network Involving Cytochromes P450 and Vitamin D

Inflammatory response represents one of the main mechanisms of healing and tissue function restoration. On the other hand, chronic inflammation leads to excessive secretion of pro-inflammatory cytokines involved in the onset of several diseases. Oxidative stress condition may contribute in worsening inflammatory state fall, increasing reactive oxygen species (ROS) production and cytokines release. Polyphenols can counteract inflammation and oxidative stress, modulating the release of toxic molecules and interacting with physiological defenses, such as cytochromes p450 enzymes. In this paper, we aimed at evaluating the anti-inflammatory properties of different concentrations of Myrtus communis L. pulp and seeds extracts, derived from liquor industrial production, on human fibroblasts. We determined ROS production after oxidative stress induction by H2O2 treatment, and the gene expression of different proinflammatory cytokines. We also analyzed the expression of CYP3A4 and CYP27B1 genes, in order to evaluate the capability of Myrtus polyphenols to influence the metabolic regulation of other molecules, including drugs, ROS, and vitamin D. Our results showed that Myrtus extracts exert a synergic effect with vitamin D in reducing inflammation and ROS production, protecting cells from oxidative stress damages. Moreover, the extracts modulate CYPs expression, preventing chronic inflammation and suggesting their use in development of new therapeutic formulations.

(-)-Epigallocatechin-3-gallate (EGCG) enhances healing of femoral bone defect

BACKGROUND

Previously, we found that (-)-epigallocatechin-3-gallate (EGCG) enhanced osteogenic differentiation of murine bone marrow mesenchymal stem cells by increasing the mRNA expression of osteogenesis-related genes, alkaline phosphatase activity and eventually mineralization. We further found EGCG supplementation preserved bone mass and microarchitecture in female rats during estrogen deficiency in the proximal tibia and lumbar spine at least in part by increasing bone morphogenetic protein-2 (BMP2). BMP2 can enhance de novo bone formation.

PURPOSE

In this study, we evaluate the effect of local EGCG application in de novo bone formation in bone defect healing.

METHODS

Twenty-four rats aged 4 months were weight-matched and randomly allocated to 2 groups: defect control with vehicle treatment (control) and defect with 10 µM EGCG treatment (EGCG). Daily vehicle and EGCG were applied locally by percutaneous local injection 2 days after defect creation for 2 weeks. Four weeks after treatment, animals were sacrificed for micro-computed tomography (μ-CT) and biomechanical analysis.

RESULTS

Local EGCG at femoral defect can enhance de novo bone formation by increasing bone volume and subsequently improve mechanical properties including max load, break point, stiffness, area under the max load curve, area under the break point curve and ultimate stress.

CONCLUSIONS

Local EGCG may enhance bone defect healing via at least partly by the de novo bone formation of BMP-2.

(-)-Epigallocatechin-3-Gallate Decreases Osteoclastogenesis via Modulation of RANKL and Osteoprotegrin

Osteoporosis is the second most common epidemiologic disease in the aging population worldwide. Previous studies have found that frequent tea drinkers have higher bone mineral density and less hip fracture. We previously found that (-)-epigallocatechin gallate (EGCG) (20⁻100 µmol/L) significantly suppressed receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclastogenesis and pit formation via inhibiting NF-κB transcriptional activity and nuclear transport of NF-κB in RAW 264.7 cells and murine primary bone marrow macrophage cells. The most important regulation in osteoclastogenesis is the receptor activator of nuclear factor-kB/RANKL/osteoprotegrin (RANK/RANKL/OPG) pathway. In this study, we used the coculture of RAW 264.7 cells and the feeder cells, ST2, to evaluate how EGCG regulated the RANK/RANKL/OPG pathway in RAW 264.7 cells and ST2 cells. We found EGCG decreased the RANKL/OPG ratio in both mRNA expression and secretory protein levels and eventually decreased osteoclastogenesis by TRAP (+) stain osteoclasts and TRAP activity at low concentrations-1 and 10 µmol/L-via the RANK/RANKL/OPG pathway. The effective concentration can be easily achieved in daily tea consumption. Taken together, our results implicate that EGCG could be an important nutrient in modulating bone resorption.

Tocotrienols for bone health: a translational approach

Osteoporosis, a degenerative bone disease, is characterized by low bone mass and microstructural deterioration of bone tissue resulting in aggravated bone fragility and susceptibility to fractures. The trend of extended life expectancy is accompanied by a rise in the prevalence of osteoporosis and concomitant complications in the elderly population. Epidemiological evidence has shown an association between vitamin E consumption and the prevention of age-related bone loss in elderly women and men. Animal studies show that ingestion of vitamin E, especially tocotrienols, may benefit bone health in terms of maintaining higher bone mineral density and improving bone microstructure and quality. The beneficial effects of tocotrienols on bone health appear to be mediated via antioxidant/anti-inflammatory pathways and/or 3-hydroxy-3-methylglutaryl coenzyme A mechanisms. We discuss (1) an overview of the prevalence and etiology of osteoporosis, (2) types of vitamin E (tocopherols versus tocotrienols), (3) findings of tocotrienols and bone health from published in vitro and animal studies, (4) possible mechanisms involved in bone protection, and (5) challenges and future direction for research.

Tea flavonoids for bone health: from animals to humans

Osteoporosis is a skeletal disease characterized by a deterioration of bone mass and bone quality that predisposes an individual to a higher risk of fragility fractures. Emerging evidence has shown that the risk for low bone mass and osteoporosis-related fractures can be reduced by nutritional approaches aiming to improve bone microstructure, bone mineral density, and strength. Tea and its flavonoids, especially those of black tea and green tea, have been suggested to protect against bone loss and to reduce risk of fracture, due to tea's antioxidant and anti-inflammatory properties. Based on the results of animal studies, moderate intake of tea has shown to benefit bone health as shown by mitigation of bone loss and microstructural deterioration as well as improvement of bone strength and quality. Epidemiological studies have reported positive, insignificant, and negative impacts on bone mineral density at multiple skeletal sites and risk of fracture in humans with habitual tea consumption. There are limited human clinical trials that objectively and quantitatively assessed tea consumption and bone efficacy using validated outcome measures in a population at high risk for osteoporosis, along with safety monitoring approach. This review summarizes the current state of knowledge of laboratory animal research, epidemiological observational studies, and clinical trials assessing the skeletal effects of tea and its active flavonoids, along with discussion of relevant future directions in translational research.

Rabbiteye blueberry prevents osteoporosis in ovariectomized rats

Objective

It has been forecasted that the rabbiteye blueberry could inhibit osteoporosis. However, the inhibition and prevention of osteoporosis via rabbiteye blueberry are still elusive. This study was aim to evaluate the anti-osteoporosis effects of rabbiteye blueberry in ovariectomized rats.

Methods

Thirty rats were randomly divided into three groups of ten rats each as follows: sham-operated group (SG), ovariectomized model control group (OMG), and ovariectomized rabbiteye blueberry treatment group (OBG). The blood mineral levels, the alkaline phosphatase (ALP) activity, and osteoprotegerin (OPG) level were determined. The expression analyses of type I collagen, integrin-β1, and focal adhesion kinase (FAK) were performed. Besides, the bone mineral density (BMD) and bone histomorphometry (BH) were measured.

Results

The ALP activity in SG and OBG was significantly lower than that in OMG. For the OPG level, the significant increase of OPG level in OBG was indicated compared with the other groups. The mRNA expression levels of type I collagen, integrin-β1, and FAK in OMG were significantly lower than those in other groups. The BMD in OMG were all significantly lower than those in SG and OBG. For BH, blueberry significantly improved the trabecular bone volume fraction, trabecular thickness, mean trabecular bone number, and bone formation rate, and decreased the trabecular separation, the percent of bone resorption perimeter, and mean osteoclast number in OBG compared with OMG.

Conclusions

The rabbiteye blueberries had an effective inhibition in bone resorption, bone loss, and reduction of bone strength of ovariectomized rats and could improve the BMD, osteogenic activity, and trabecular bone structure.

Green Tea Extract (GTE) improves differentiation in human osteoblasts during oxidative stress

Background

Oxidative stress is involved in the pathogenesis of bone diseases such as osteoporosis, which has a high coincidence with fractures in elderly. Several studies showed positive effects of herbal bioactive substances on oxidative stress. This study analyses the effect of green tea extract (GTE) Sunphenon 90LB on primary human osteoblasts differentiation and viability during H₂O₂-induced oxidative stress. Moreover, it was analyzed, whether GTE acts during the HO-1 signaling pathway.

Methods

Human osteoblasts were isolated from femoral heads of patients undergoing total hip replacement. Beneficial effects of GTE on osteoblasts were examined in a dose- and time-dependent manner. Furthermore, GTE was given before, simultaneous with and after induction of oxidative stress with 1 mM H₂O₂ to simulate prophylactic, acute and therapeutic use, respectively. Cell damage was measured by LDH leakage and cell viability by MTT assay. Flow cytometry was applied to measure formation of Reactive Oxygen Species by using 2`7`-dichlorofluorescein-diacetate. The formation of Extracellular Matrix after differentiation with GTE supplementation during oxidative stress was visualized with von Kossa and Alizarin Red staining. Last one was additionally photometrically quantified. To assess the effects of H₂O₂ and GTE on the osteogenic genes, RT-PCR was performed. To evaluate the intramolecular influence of GTE after the stimulation the protein levels of HO-1 were analyzed.

Results

Stimulation of primary human osteoblasts with low doses of GTE during oxidative stress over 21 days improved mineralization. Furthermore, GTE supplementation in combination with H₂O₂ leads to a higher gene expression of osteocalcin and collagen1α1 during osteoblasts differentiation. Both are important for bone quality. Pre-incubation, co-incubation and post-incubation of osteoblasts with high doses of GTE protect the osteoblasts against acute oxidative stress as shown by increased cell viability, decreased LDH leakage, and reduced production of intracellular free radicals. Functional analysis revealed an increased HO-1 protein synthesis after stimulation with GTE.

Conclusions

Incubation of human primary osteoblasts with GTE significantly reduces oxidative stress and improves cell viability. GTE also has a beneficial effect on ECM production which might improve the bone quality. Our findings suggest that dietary supplementation of GTE might reduce inflammatory events in bone-associated diseases such as osteoporosis.

Clearance of free silica in rat lungs by spraying with chinese herbal kombucha

The effects of spraying with kombucha and Chinese herbal kombucha were compared with treatments with tetrandrine in a rat silicosis model. Silica dust (50 mg) was injected into the lungs of rats, which were then treated with one of the experimental treatments for a month. The rats were then killed and the effects of the treatments were evaluated by examining the extent and severity of the histopathological lesions in the animals' lungs, measuring their organ coefficients and lung collagen contents, determining the dry and wet weights of their lungs, and measuring the free silica content of the dried lungs. In addition, lavage was performed on whole lungs taken from selected rats, and the numbers and types of cells in the lavage fluid were counted. The most effective treatment in terms of the ability to reduce lung collagen content and minimize the formation of pulmonary histopathological lesions was tetrandrine treatment, followed by Chinese herbal kombucha and non-Chinese herbal kombucha. However, the lavage fluid cell counts indicated that tetrandrine treatment had severe adverse effects on macrophage viability. This effect was much less pronounced for the kombucha and Chinese herbal kombucha treatments. Moreover, the free silica levels in the lungs of animals treated with Chinese herbal kombucha were significantly lower than those for any other silica-exposed group. These preliminary results indicate that spraying with Chinese herbal kombucha preparations can effectively promote the discharge of silica dust from lung tissues. Chinese herbal kombucha inhalation may thus be a useful new treatment for silicosis and other pneumoconiosis diseases.

Phytonutrients for bone health during ageing

Osteoporosis is a skeletal disease characterized by a decrease in bone mass and bone quality that predispose an individual to an increased risk of fragility fractures. Evidence demonstrating a positive link between certain dietary patterns (e.g. Mediterranean diet or high consumption of fruits and vegetables) and bone health highlights an opportunity to investigate their potential to protect against the deterioration of bone tissue during ageing. While the list of these phytonutrients is extensive, this review summarizes evidence on some which are commonly consumed and have gained increasing attention over recent years, including lycopene and various polyphenols (e.g. polyphenols from tea, grape seed, citrus fruit, olive and dried plum). Evidence to define a clear link between these phytonutrients and bone health is currently insufficient to generate precise dietary recommendations, owing to mixed findings or a scarcity in clinical data. Moreover, their consumption typically occurs within the context of a diet consisting of a mix of phytonutrients and other nutrients rather than in isolation. Future clinical trials that can apply a robust set of outcome measurements, including the determinants of bone strength, such as bone quantity (i.e. bone mineral density) and bone quality (i.e. bone turnover and bone microarchitecture), will help to provide a more comprehensive outlook on how bone responds to these various phytonutrients. Moreover, future trials that combine these phytonutrients with established bone nutrients (i.e. calcium and vitamin D) are needed to determine whether combined strategies can produce more robust effects on skeletal health.

Celastrus and its bioactive celastrol protect against bone damage in autoimmune arthritis by modulating osteoimmune cross-talk

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by bone erosion and cartilage destruction in the joints. Many of the conventional antiarthritic drugs are effective in suppressing inflammation, but they do not offer protection against bone damage. Furthermore, the prolonged use of these drugs is associated with severe adverse reactions. Thus, new therapeutic agents that can control both inflammation and bone damage but with minimal side effects are sought. Celastrus is a Chinese herb that has been used for centuries in folk medicine for the treatment of various inflammatory diseases. However, its utility for protection against inflammation-induced bone damage in arthritis and the mechanisms involved therein have not been examined. We tested celastrus and its bioactive component celastrol for this attribute in the adjuvant-induced arthritis model of RA. The treatment of arthritic rats with celastrus/celastrol suppressed inflammatory arthritis and reduced bone and cartilage damage in the joints as demonstrated by histology and bone histomorphometry. The protective effects against bone damage are mediated primarily via the inhibition of defined mediators of osteoclastic bone remodeling (e.g. receptor activator of nuclear factor-κB ligand (RANKL)), the deviation of RANKL/osteoprotegerin ratio in favor of antiosteoclastic activity, and the reduction in osteoclast numbers. Furthermore, both the upstream inducers (proinflammatory cytokines) and the downstream effectors (MMP-9) of the osteoclastogenic mediators were altered. Thus, celastrus and celastrol controlled inflammation-induced bone damage by modulating the osteoimmune cross-talk. These natural products deserve further consideration and evaluation as adjuncts to conventional therapy for RA.

Bone turnover markers correlate with implant fixation in a rat model using LPS-doped particles to induced implant loosening

Revision surgery for particle-induced implant loosening in total joint replacement is expected to increase dramatically over the next few decades. This study was designed to investigate if local tissue and serum markers of bone remodeling reflect implant fixation following administration of lipopolysaccharide (LPS)-doped polyethylene (PE) particles in a rat model. Twenty-four rats received bilateral implantation of intramedullary titanium rods in the distal femur, followed by weekly bilateral intra-articular injection of either LPS-doped PE particles (n = 12) or vehicle that contained no particles (n = 12) for 12 weeks. The group in which the particles were injected had increased serum C-terminal telopeptide of type I collagen (CTX-I), decreased serum osteocalcin (OC), increased peri-implant eroded surface, decreased peri-implant bone volume, and decreased mechanical pull-out strength compared to the controls. Implant fixation strength was positively correlated with peri-implant bone volume and serum OC and inversely correlated with serum CTX-I, while energy to yield was positively correlated with serum OC and inversely correlated with the number of tartrate-resistant acid phosphatase positive cells at the interface and the amount of peri-implant eroded surface. There was no effect on trabecular bone volume at a remote site. Thus, the particle-induced impaired fixation in this rat model was directly associated with local and serum markers of elevated bone resorption and depressed bone formation, supporting the rationale of exploring both anticatabolic and anabolic strategies to treat and prevent particle-related implant osteolysis and loosening, and indicating that serum markers may prove useful in tracking implant fixation.

Green tea and bone health: Evidence from laboratory studies

Osteoporosis is a major health problem in the elderly. Epidemiological evidence has shown an association between tea consumption and the prevention of bone loss in the elderly population. Ingestion of green tea and green tea bioactive compounds may be beneficial in mitigating bone loss of this population and decreasing their risk of osteoporotic fractures. This review describes the effect of green tea with its bioactive components on bone health with an emphasis on the following: (i) the etiology of osteoporosis, (ii) evidence of osteo-protective impacts of green tea on bone mass and microarchitecture in various bone loss models in which induced by aging, sex hormone deficiency, and chronic inflammation, (iii) discussion of impacts of green tea on bone mass in two obesity models, (iv) observation of short-term green tea supplementation given to postmenopausal women with low bone mass, (v) possible mechanisms for the osteo-protective effects of green tea bioactive compounds, and (vi) a summary and future research direction of green tea and bone health.

Immunomodulation of Autoimmune Arthritis by Herbal CAM

Rheumatoid arthritis (RA) is a debilitating autoimmune disease of global prevalence. The disease is characterized by synovial inflammation leading to cartilage and bone damage. Most of the conventional drugs used for the treatment of RA have severe adverse reactions and are quite expensive. Over the years, increasing proportion of patients with RA and other immune disorders are resorting to complementary and alternative medicine (CAM) for their health needs. Natural plant products comprise one of the most popular CAM for inflammatory and immune disorders. These herbal CAM belong to diverse traditional systems of medicine, including traditional Chinese medicine, Kampo, and Ayurvedic medicine. In this paper, we have outlined the major immunological pathways involved in the induction and regulation of autoimmune arthritis and described various herbal CAM that can effectively modulate these immune pathways. Most of the information about the mechanisms of action of herbal products in the experimental models of RA is relevant to arthritis patients as well. The study of immunological pathways coupled with the emerging application of genomics and proteomics in CAM research is likely to provide novel insights into the mechanisms of action of different CAM modalities.