Selective effects of genistein, a soybean isoflavone, on B-lymphopoiesis and bone loss caused by estrogen deficiency

Pharmacological Therapies for the Management of Inflammatory Bone Resorption in Periodontal Disease: A Review of Preclinical Studies

Periodontitis, a highly prevalent multicausal chronic inflammatory and destructive disease, develops as a result of complex host-parasite interactions. Dysbiotic bacterial biofilm in contact with the gingival tissues initiates a cascade of inflammatory events, mediated and modulated by the host's immune response, which is characterized by increased expression of several inflammatory mediators such as cytokines and chemokines in the connective tissue. If periodontal disease (PD) is left untreated, it results in the destruction of the supporting tissues around the teeth, including periodontal ligament, cementum, and alveolar bone, which lead to a wide range of disabilities and poor quality of life, thus imposing significant burdens. This process depends on the differentiation and activity of osteoclasts, the cells responsible for reabsorbing the bone tissue. Therefore, the inhibition of differentiation or activity of these cells is a promising strategy for controlling bone resorption. Several pharmacological drugs that target osteoclasts and inflammatory cells with immunomodulatory and anti-inflammatory effects, such as bisphosphonates, anti-RANK-L antibody, strontium ranelate, cathepsin inhibitors, curcumin, flavonoids, specialized proresolving mediators, and probiotics, were already described to manage inflammatory bone resorption during experimental PD progression in preclinical studies. Meantime, a growing number of studies have described the beneficial effects of herbal products in inhibiting bone resorption in experimental PD. Therefore, this review summarizes the role of several pharmacological drugs used for PD prevention and treatment and highlights the targeted action of all those drugs with antiresorptive properties. In addition, our review provides a timely and critical appraisal for the scientific rationale use of the antiresorptive and immunomodulatory medications in preclinical studies, which will help to understand the basis for its clinical application.

Synthesis and characterization of genistein magnetic molecularly imprinted polymers and their application in soy sauce products

In this study, a novel method based on genistein magnetic molecularly imprinted polymers (Gen-MMIPs) was developed utilizing a surface molecular imprinting technique, in which genistein was used as the template molecule and Fe₃O₄ was used as the carrier. The synthesis of Gen-MMIPs was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which indicated that the diameter of the Gen-MMIPs was approximately 500 nm. Via analysis with a vibrating sample magnetometer (VSM), the saturation magnetization of Gen-MMIPs was determined to be 24.79 emu g⁻¹. Fourier transform infrared (FT-IR) spectroscopy showed that polymer groups were on the surface of the magnetic carrier. Adsorption experiments suggested that the genistein adsorption capability of Gen-MMIPs was 5.81 mg g⁻¹, and adsorption equilibrium was achieved within 20 min. Gen-MMIPs as dispersive solid-phase extraction (dSPE) adsorbents combined with HPLC were used to selectively separate genistein in soy sauce samples, and the recoveries ranged from 85.7 to 88.5% with relative standard deviations (RSDs) less than 5%, which proved that this method can be used for the detection of genistein residues in real samples.

The Combination of Soy Isoflavones and Resveratrol Preserve Bone Mineral Density in Hindlimb-Unloaded Mice

It is well known that physical inactivity during space flight or prolonged bed rest causes rapid bone loss. Soy isoflavones (ISOs) and resveratrol (RES) have been reported to be useful to maintain a positive balance for bone turnover. Therefore, we examined the combined effects of ISO and RES on bone loss that was induced by hindlimb-unloading in mice. Female eight-week-old ddY mice were divided into the following six groups (n = 6-8 each): normally housed mice, loading mice, hindlimb-unloading (UL) mice fed a control diet, UL mice fed a 0.16% ISO conjugates, UL mice fed a 0.15% RES diet, and UL mice fed a 0.16% ISO and 0.15% RES diet. After three weeks, femoral bone mineral density was markedly decreased in unloading mice. The combination of ISO and RES prevented bone loss and especially maintained the trabecular bone mineral density more effectively compared with cortical bones. ISO and/or RES inhibited the increase in the RANKL/OPG expression ratio in bone marrow cells in UL mice. These results suggest that the combination of ISO and RES had a preventive effect against bone loss induced by hindlimb-unloading in mice. These osteoprotective effects of ISO and RES may result from the inhibition of bone resorption.

Selective dietary polyphenols induce differentiation of human osteoblasts by adiponectin receptor 1-mediated reprogramming of mitochondrial energy metabolism

Anabolic therapies for osteoporosis including dietary polyphenols promote osteoblast function by influencing its energy metabolism. Among the dietary polyphenols, the beneficial skeletal effects of genistein (an isoflavone), kaempferol (a flavone), resveratrol (RES, a stilbenoid) and epigallocatechin gallate (EGCG, a catechin) have been reported in preclinical studies. We studied the action mechanism of these nutraceuticals on osteoblast bioenergetics. All stimulated differentiation of human fetal osteoblasts (hFOB). However, only EGCG and RES stimulated mitochondrial parameters including basal and maximum respiration, spare respiratory capacity and ATP production (a measure of the activity of electron transport chain/ETC). Increases in these parameters were due to increased mitochondrial biogenesis and consequent upregulation of several mitochondrial proteins including those involved in ETC. Rotenone blocked the osteogenic effect of EGCG and RES suggesting the mediatory action of mitochondria. Both compounds rapidly activated AMPK, and dorsomorphin (an AMPK inhibitor) abolished ATP production stimulated by these compounds. Moreover, EGCG and RES upregulated the mitochondrial biogenesis factor, PGC-1α which is downstream of AMPK activation, and silencing PGC-1α blocked their stimulatory effects on ATP production and hFOB differentiation. Adiponectin receptor 1 (AdipoR1) is an upstream regulator of PGC-1α, and both compounds increased the expression of AdipoR1 but not AdipoR2. Silencing AdipoR1 blocked the upregulation of EGCG/RES-induced PGC-1α and hFOB differentiation. In rat calvarium, both compounds increased AdipoR1, PGC-1α, and RunX2 (the osteoblast transcription factor) with a concomitant increase in mitochondrial copy number and ATP levels. We conclude that EGCG and RES display osteogenic effects by reprogramming osteoblastic bioenergetics by acting as the AdipoR1 agonists.

Soybean isoflavone can protect against osteoarthritis in ovariectomized rats

Osteoarthritis (OA) is a chronic and incurable disease and a leading cause of significant pain and disability that is closely associated with aging and obesity. An appropriate long-term therapy regimen is presently unknown. An estrogen deficiency after menopause increases the incidence and severity of OA in women. Soybean isoflavone have weak estrogenic effects in several organs and have been considered as a potentially safe natural selective estrogen receptor modulator. The present study aimed to determine the effects of isoflavone on cartilage degradation in ovariectomized rats. Six-month-old female Sprague-Dawley (SD) rats (n = 40) were randomly assigned to sham operation (n = 10), ovariectomy (OVX) (n = 15) or OVX + isoflavone (OVXI) (n = 15) groups. The OVXI group was fed with soybean isoflavone (51.0 mg/kg/day) for nine weeks, then knee joints were excised. Cartilage degradation was evaluated by toluidine blue staining joint specimens, and by comparing values for serum C-telopeptides of Type II collagen (CTX-II) and cartilage oligomeric matrix protein (COMP) between baseline and the end of the study. Cartilage damage scored by Toluidine blue staining was significantly lower in the OXVI, than the OVX group (P < 0.016). The CTX-II values before the surgical procedure and the end of experiment, did not significantly differ among the groups. Values for COMP in all samples were below detection limits in all samples. Soy bean isoflavone limited the degeneration of cartilage induced by OVX in rats.

Using okara in diets for growing broilers

This study aimed to evaluate the effects of okara inclusion in diet for growing broilers on performance, carcass yield, blood and bone variables, quality and lipid oxidation of meat, and economic viability. For that, 575 Cobb 21-d-old male broilers were distributed in a completely randomized design with four levels of okara inclusion (25, 50, 75, and 100 g of okara kg−1diet) and a control group with five replicates and 23 birds each. There was no significant difference (P > 0.05) of okara levels on the performance variables, carcass yield, bone variables, and serum triglycerides, calcium and phosphorus at 42-d-old. Serum cholesterol levels showed a quadratic response (P < 0.05), in which the lowest value estimated was 65.3 g of okara kg−1of diet. Okara can be included in diets for broilers up to the level of 100 g kg−1without affecting the performance, carcass yield, bone variables, and lipid oxidation of meat. However, the best economic results were observed up to 50 g of okara kg−1of diet.

Androgens and Androgen Receptor Actions on Bone Health and Disease: From Androgen Deficiency to Androgen Therapy

Androgens are not only essential for bone development but for the maintenance of bone mass. Therefore, conditions with androgen deficiency, such as male hypogonadism, androgen-insensitive syndromes, and prostate cancer with androgen deprivation therapy are strongly associated with bone loss and increased fracture risk. Here we summarize the skeletal effects of androgens—androgen receptors (AR) actions based on in vitro and in vivo studies from animals and humans, and discuss bone loss due to androgens/AR deficiency to clarify the molecular basis for the anabolic action of androgens and AR in bone homeostasis and unravel the functions of androgen/AR signaling in healthy and disease states. Moreover, we provide evidence for the skeletal benefits of androgen therapy and elucidate why androgens are more beneficial than male sexual hormones, highlighting their therapeutic potential as osteoanabolic steroids in improving bone fracture repair. Finally, the application of selective androgen receptor modulators may provide new approaches for the treatment of osteoporosis and fractures as well as building stronger bones in diseases dependent on androgens/AR status.

Estrogen therapy associated with mechanical vibration improves bone microarchitecture and density in osteopenic female mice

We investigated the effects of estrogen therapy (ET) associated with low-intensity and high-frequency mechanical vibration (MV) on bone tissue in osteopenic female mice. Fifty 3-month-old female Swiss mice were ovariectomized (OVX) or sham-operated, and distributed after 4 months into the following groups, with 10 animals per group: Sham; Control, OVX + vehicle solution; MV, OVX + MV; ET, OVX + 17β-estradiol; and MV + ET, OVX + MV and 17β-estradiol. Both vehicle solution and 17β-estradiol (10 μg kg-1  day-1 ) were injected subcutaneously 7 days per week, and vibration (0.6 g, 60 Hz) was delivered 30 min per day, 5 days per week. Bone mineral density (BMD) and body composition were evaluated by densitometry at baseline and after 60 days of treatment when the animals were euthanized, and their femurs underwent histomorphometric and histochemical analyses. The Control group showed increased weight and fat percentage, while the ET and MV + ET groups showed increased lean mass but decreased fat percentage. At the end of the treatment period, the BMD decreased in Control, remained constant in Sham and MV, and increased in ET and MV + ET. The MV + ET group showed the greatest bone volume compared with Sham (129%), Control (350%), MV (304%) and ET (14%). No differences occurred in cortical thickness. The Control group showed the highest content of mature collagen fibers, while the MV + ET group showed the highest content of immature collagen fibers. In conclusion, ET plus MV was effective in improving bone quality in osteopenic female mice, and this improvement is associated with specific changes in trabecular but not cortical bone.

Suppression Effect of Astaxanthin on Osteoclast Formation In Vitro and Bone Loss In Vivo

Osteoporosis is characterized by a reduction of the bone mineral density (BMD) and microarchitectural deterioration of the bone, which lead to bone fragility and susceptibility to fracture. Astaxanthin (AST) has a variety of biological activities, such as a protective effect against asthma or neuroinflammation, antioxidant effect, and decrease of the osteoclast number in the right mandibles in the periodontitis model. Although treatment with AST is known to have an effect on inflammation, no studies on the effect of AST exposure on bone loss have been performed. Thus, in the present study, we examined the antiosteoporotic effect of AST on bone mass in ovariectomized (OVX) mice and its possible mechanism of action. The administration of AST (5, 10 mg/kg) for 6 weeks suppressed the enhancement of serum calcium, inorganic phosphorus, alkaline phosphatase, total cholesterol, and tartrate-resistant acid phosphatase (TRAP) activity. The bone mineral density (BMD) and bone microarchitecture of the trabecular bone in the tibia and femur were recovered by AST exposure. Moreover, in the in vitro experiment, we demonstrated that AST inhibits osteoclast formation through the expression of the nuclear factor of activated T cells (NFAT) c1, dendritic cell-specific transmembrane protein (DC-STAMP), TRAP, and cathepsin K without any cytotoxic effects on bone marrow-derived macrophages (BMMs). Therefore, we suggest that AST may have therapeutic potential for the treatment of postmenopausal osteoporosis.

A Major Population of Functional KLRG1- ILC2s in Female Lungs Contributes to a Sex Bias in ILC2 Numbers

Humans show significant sex differences in the incidence and severity of respiratory diseases, including asthma and virus infection. Sex hormones contribute to the female sex bias in type 2 inflammation associated with respiratory diseases, consistent with recent reports that female lungs harbor greater numbers of GATA-3-dependent group 2 innate lymphoid cells (ILC2s). In this study, we determined whether sex hormone levels govern sex differences in the numbers, phenotype, and function of ILC2s in the murine lung and bone marrow (BM). Our data show that lungs of female mice harbor significantly greater ILC2 numbers in homeostasis, in part due to a major subset of ILC2s lacking killer-cell lectin like receptor G1 (KLRG1), a population largely absent in male lungs. The KLRG1^- ILC2s were capable of type 2 cytokine production and increased with age after sexual maturity, suggesting that a unique functional subset exists in females. Experiments with gonadectomized mice or mice bearing either global or lymphocyte restricted estrogen receptor α (Esr1) deficiency showed that androgens rather than estrogens regulated numbers of the KLRG1^- ILC2 subset and ILC2 functional capacity in the lung and BM, as well as levels of GATA-3 expression in BM ILC2s. Furthermore, the frequency of BM PLZF⁺ ILC precursors was higher in males and increased by excess androgens, suggesting that androgens act to inhibit the transition of ILC precursors to ILC2s. Taken together, these data show that a functional subset of KLRG1^- ILC2s in females contributes to the sex bias in lung ILC2s that is observed after reproductive age.

Lutein Enhances Bone Mass by Stimulating Bone Formation and Suppressing Bone Resorption in Growing Mice

Lutein is a member of the xanthophyll family of carotenoids, which are known to prevent hypoxia-induced cell damage in the eye by removing free radicals. However, its role in other tissues is controversial, and the effects of lutein on bone tissues are unknown. To identify a possible role of lutein in bone tissues, we examined the effects of lutein on bone formation and bone resorption and on femoral bone mass in mice. Lutein enhanced the formation of mineralized bone nodules in cultures of osteoblasts. On the other hand, lutein clearly suppressed 1α, 25-dihydroxyvitamin D₃-induced bone resorption as measured by pit formation in organ culture of mouse calvaria. In co-cultures of bone marrow cells and osteoblasts, lutein suppressed 1α, 25-dihydroxyvitamin D₃-induced osteoclast formation. In cultures of bone marrow macrophages, lutein suppressed soluble RANKL, the receptor activator of nuclear factor-kappaB (NF-κB) ligand, induced osteoclast formation. When five-week-old male mice were orally administered lutein for 4 weeks, the femoral bone mass was clearly enhanced in cortical bone, as measured by bone mineral density in dual X-ray absorptiometry and micro computed tomography (µCT) analyses. The present study indicates that lutein enhances bone mass in growing mice by suppressing bone resorption and stimulating bone formation. Lutein may be a natural agent that promotes bone turnover and may be beneficial for bone health in humans.

Effects of combined treatment with fermented soybean (natto) intake and exercise on bone metabolism in ovariectomized rats

OBJECTIVES

Using ovariectomized rats, we examined the influence of combined exercise tolerance and natto intake on the bone loss inhibitory effect.

METHODS

We divided female Wistar rats into the following groups: Ovariectomy, Ovariectomy + Exercise, Ovariectomy + Natto Intake, Ovariectomy + Exercise + Natto Intake, and Pseudo-operative (Sham group). After conducting experiments on each group, we collected the tissues and performed morphological and molecular biological analyses.

RESULTS

In comparison with the Ovariectomy group, only in the Ovariectomy + Exercise group was there a significant bone loss inhibitory effect in the femoral cancellous bone. Although there was a tendency toward this trend seen in the Natto Intake and Exercise + Natto Intake groups, these differences were not significant. The increase in messenger RNA expression levels of alkaline phosphatase (osteoblast marker) in the bone marrow caused by ovariectomy was suppressed by individual factors, and by those in combination. However, messenger RNA expression levels of estrogen receptor alpha in the bone marrow showed a decreasing tendency with each factor, and decreased significantly with the combination, similar to the Sham group.

CONCLUSION

This suggests that natto intake and exercise maintain bone mass by different molecular mechanisms and that these two factors do not simply act synergistically in combination to maintain bone mass.

Isoflavones improve vascular reactivity in post-menopausal women with hypercholesterolemia

This randomized clinical trial was designed to assess the effects of dietary isoflavones on vascular reactivity, lipid levels, and markers of inflammation in post-menopausal women. Epidemiological studies have revealed that populations consuming large amounts of soy protein have lower cardiovascular morbidity and mortality. The benefits of soy protein may be due to its hypolipidemic effects; its anti-oxidant properties; its high content of L-arginine; and=or or its phytoestrogen content. Two putative mediators of the effects of soy protein are the isoflavones genistein and daidzein. Forty post-menopausal, hypercholesterolemic women who did not take estrogen replacement therapy were recruited for this study of isoflavone supplementation. Baseline flow-mediated vasodilation and response to nitroglycerin were measured, along with urinary isoflavone and nitrite=nitrate levels and serum lipids. After 6 weeks of 90 mg of isoflavones daily versus placebo, women receiving isoflavones demonstrated improved responsiveness to nitroglycerin, an assessment of endothelium-independent vasodilation, with an effect size (percentage points change from baseline) of 7.2 1.9 versus 1.2 1.3; p = 0.01. There was a trend towards improvement of flow-mediated vasodilation, which is an endothelium-dependent response (effect size: 3.4 2.0% versus -0.6 1.7%; p = 0.12). Lipid levels were unchanged after isoflavone treatment. In conclusion, dietary isoflavones may have cardiovascular benefit in the form of improved vascular reactivity, but not by lowering cholesterol, for women who do not take estrogen replacement therapy.

Kanamycin inhibits daidzein metabolism and abilities of the metabolites to prevent bone loss in ovariectomized mice

BACKGROUND

Daidzein is an isoflavone derived from soybeans that exerts preventive effects on bone loss in ovariectomized (OVX) animals. These effects have been correlated with increasing serum equol levels. In the present study, we investigated the effects of antibiotic intake on equol metabolism from daidzein, and the corresponding levels of bone loss in OVX mice.

METHODS

Eight-week-old female ddY mice (n = 42) were either ovariectomized (OVX) or subjected to a sham operation (sham). OVX mice were then divided into six dietary subgroups: control diet (control), 0.3 % kanamycin diet (KN), 0.1 % daidzein diet (Dz), 0.1 % daidzein and 0.0375 % kanamycin diet (Dz+KN3.75), 0.1 % daidzein and 0.075 % kanamycin diet (Dz+KN7.5), and 0.1 % daidzein and 0.3 % kanamycin diet (Dz+KN30). The mice were fed their respective diets for 4 weeks.

RESULTS

Uterine weight and femoral bone mineral density (BMD) were significantly lower in the OVX mice compared in the sham mice. No significant differences in uterine weight were observed among all OVX dietary subgroups. The Dz subgroup was found to exhibit higher plasma equol and O-desmethylangolensin (O-DMA) concentrations, as well as greater femoral BMD, compared to all other OVX subgroups. Furthermore, when compared to the Dz group, kanamycin intake decreased plasma equol and O-DMA concentrations, as well as femoral BMD in the OVX mice.

CONCLUSIONS

These results suggest that kanamycin intake inhibited the conversion of daidzein to equol and O-DMA, blocking the preventive effects of daidzein on bone loss in OVX mice. Therefore, the bone-protective effects of daidzein intake may be predominantly associated with increased plasma concentrations of either equol or O-DMA.

Preclinical studies and clinical evaluation of compounds from the genus Epimedium for osteoporosis and bone health

The morbidity and mortality associated with fractures due to osteoporosis or "porous bone" contributes significantly to global healthcare costs and will increase exponentially with ageing populations. In menopausal women, the onset of menopause and rapid estrogen withdrawal leads to osteoporotic fractures. Healthy bone requires the coordinated remodeling function of osteoclasts, osteoblasts, and osteocytes in the basic bone multicellular unit, regulated by estrogen, RANKL/OPG, ROS, growth factors, and other kinase signaling pathways. Anti-osteoporotic drugs in current use such as hormone replacement therapy, selective estrogen receptor modulators, and bisphosphonates are designed to target these pathways, but all have their limitations. Extracts of the dried aerial parts of the traditional Chinese medicinal plant Epimedium (Berberidaceae) has long been used for bone health. Some nine Epimedium prenylflavonoid compounds have been reported to target estrogen signaling and other bone morphogenesis pathways in mesenchymal stem cell, osteoblast, and osteoclast cell lineages. Epimedium prenylflavonoids and enriched extracts can exert beneficial effects on bone health in estrogen-deficient and other osteoporosis animal models. The development of sensitive and rapid mass chromatographic techniques to quantify compounds extracted from Epimedium, including icariin and icaritin, has been used to standardize production and to study the pharmacokinetics and metabolism of Epimedium in animal models and humans. Recent clinical trials have reported positive effects on bone health, suggesting that compounds or extracts of Epimedium have the potential to be developed as agents, alone or in combination with other drugs, to prevent or delay the onset of osteoporosis and reduce the risk of hip fractures.

Combined effects of soy isoflavones and milk basic protein on bone mineral density in hind-limb unloaded mice

We examined whether the combination of isoflavone and milk basic protein both are reported to be effective for bone metabolism, prevents bone loss induced by skeletal hind-limb unloading in mice. Female ddY strain mice, aged 8 weeks, were divided into six groups (n = 6–8 each): (1) normally housed group, (2) loading group, (3) hind-limb unloading group fed a control diet, (4) hind-limb unloading group fed a 0.2% isoflavone conjugates diet, (5) hind-limb unloading group fed a 1.0% milk basic protein diet, and (6) hind-limb unloading group fed a 0.2% isoflavone conjugates and 1.0% milk basic protein diet. After 3 weeks, femoral bone mineral density was markedly reduced in unloading mice. The combination of isoflavone and milk basic protein showed cooperative effects in preventing bone loss and milk basic protein inhibited the increased expression of osteogenic genes in bone marrow cells in unloading mice. These results suggest that the combination of soy isoflavone and milk basic protein may be useful for bone health in subjects with disabling conditions as well as astronauts.

The Effects of Probiotic Soymilk Fortified with Omega-3 on Blood Glucose, Lipid Profile, Haematological and Oxidative Stress, and Inflammatory Parameters in Streptozotocin Nicotinamide-Induced Diabetic Rats

OBJECTIVE

The aim of the present study was to evaluate the effects of probiotic soymilk fortified with omega-3 in diabetic rats.

METHODS

Soymilk (SM), fermented soymilk (FSM), and fermented soymilk fortified with omega-3 (FSM + omega-3) were prepared. Rats were randomly assigned to five groups of 13 animals per group. Diabetes was induced by a single injection of streptozotocin (STZ) 15 min after the intraperitoneal administration of nicotinamide (NA). Normal control (NC) and diabetic control (DC) rats received 1 mL/day of distilled water and three groups of diabetic rats were given 1 mL/day of SM, FSM, and FSM + omega-3 products by oral gavage for 28 days.

RESULTS

Three products significantly (P < 0.05) reduced blood glucose, total cholesterol (TC), triglyceride (TG), and malondialdehyde (MDA) concentrations compared to the DC group, with the maximum reduction seen in the FSM + omega-3 group. Body weight, red blood cells (RBC), haemoglobin (Hb), haematocrit, and superoxide dismutase (SOD) also significantly increased in the FSM + omega-3 group. In the FSM + omega-3 group, MDA level compared with the SM and FSM groups and high sensitivity C-reactive protein (hs-CRP) concentrations compared with the DC and FSM groups were significantly lower (P < 0.05).

CONCLUSION

Fermented soymilk fortified with omega-3 may be beneficial in diabetes.

Effects of Fermentation Temperature on the Content and Composition of Isoflavones and β-Glucosidase Activity in Sufu

Sufu is a popular fermented tofu product in China. The low quality of sufu produced in the hot summer is a big problem in sufu manufacture, so we prepared sufu at two different temperatures, 26 degrees C as normal and 32 degrees C as high temperature, and the effects of temperature on isoflavones and beta-glucosidase activity were investigated. Fermentation temperature did not cause significant differences in the recovery of isoflavones, but resulted in a different redistribution of isoflavone isomers in sufu. Sufu fermented at 26 degrees C was richer in isoflavone aglycones than at 32 degrees C; the enrichment of isoflavone aglycones might have the advantage of enhancing the physiological function. No 6''-O-malonyl-glucosides were detected in sufu fermented at 26 degrees C, whereas some 6''-O-malonyl-glucosides were found at 32 degrees C. A fermentation temperature of 26 degrees C benefited the beta-glucosidase production by fungi, which contributed to valid conversion from beta-glucosides to aglycones. It was also found that beta-glucosidase converted beta-glucosides more effectively than 6''-O-malonyl-glucosides and 6''-O-acetyl-glucosides into aglycones.

Osteoprotective effect of soybean and sesame oils in ovariectomized rats via estrogen-like mechanism

The purpose of the present study was to investigate the osteoprotective effects of soybean oil (SbO) and sesame oil (SO) in ovarictomized (OVX) rats. The results indicated that the OVX rats exhibited a significant decrease in Ca and P level in both serum and bone, the activities of the antioxidant enzymes SOD and CAT and the antioxidant biomarker GSH accompanied with a marked increase in the oxidative stress markers MDA and PC, the inflammatory indices (TNF-α, CRP levels, WBCs counts and ACP activity) in, both, bone and serum. Supplementating the diet of the OVX rats with SbO (15 % w/w) or SO (10 % w/w) for 2 months to resulted in modulation of the alterations in all tested parameters and succeeded to restore minerals, antioxidant enzymes, antioxidant biomarkers, oxidative stress markers, inflammatory indices, and WBCs counts. It could be concluded that the consumption of diets supplemented with SbO or SO might be useful for preventing bone loss caused by estrogen deficiency in ovariectomy status.

The role of estrogen and androgen receptors in bone health and disease

Mouse models with cell-specific deletion of the estrogen receptor (ER) α, the androgen receptor (AR) or the receptor activator of nuclear factor κB ligand (RANKL), as well as cascade-selective estrogenic compounds have provided novel insights into the function and signalling of ERα and AR. The studies reveal that the effects of estrogens on trabecular versus cortical bone mass are mediated by direct effects on osteoclasts and osteoblasts, respectively. The protection of cortical bone mass by estrogens is mediated via ERα, using a non-nucleus-initiated mechanism. By contrast, the AR of mature osteoblasts is indispensable for the maintenance of trabecular bone mass in male mammals, but not required for the anabolic effects of androgens on cortical bone. Most unexpectedly, and independently of estrogens, ERα in osteoblast progenitors stimulates Wnt signalling and periosteal bone accrual in response to mechanical strain. RANKL expression in B lymphocytes, but not T lymphocytes, contributes to the loss of trabecular bone caused by estrogen deficiency. In this Review, we summarize this evidence and discuss its implications for understanding the regulation of trabecular and cortical bone mass; the integration of hormonal and mechanical signals; the relative importance of estrogens versus androgens in the male skeleton; and, finally, the pathogenesis and treatment of osteoporosis.

Deficiency of retinaldehyde dehydrogenase 1 induces BMP2 and increases bone mass in vivo

The effects of retinoids, the structural derivatives of vitamin A (retinol), on post-natal peak bone density acquisition and skeletal remodeling are complex and compartment specific. Emerging data indicates that retinoids, such as all trans retinoic acid (ATRA) and its precursor all trans retinaldehyde (Rald), exhibit distinct and divergent transcriptional effects in metabolism. Despite these observations, the role of enzymes that control retinoid metabolism in bone remains undefined. In this study, we examined the skeletal phenotype of mice deficient in retinaldehyde dehydrogenase 1 (Aldh1a1), the enzyme responsible for converting Rald to ATRA in adult animals. Bone densitometry and micro-computed tomography (µCT) demonstrated that Aldh1a1-deficient (Aldh1a1^−/−) female mice had higher trabecular and cortical bone mass compared to age and sex-matched control C57Bl/6 wild type (WT) mice at multiple time points. Histomorphometry confirmed increased cortical bone thickness and demonstrated significantly higher bone marrow adiposity in Aldh1a1^−/− mice. In serum assays, Aldh1a1^−/− mice also had higher serum IGF-1 levels. In vitro, primary Aldh1a1^−/− mesenchymal stem cells (MSCs) expressed significantly higher levels of bone morphogenetic protein 2 (BMP2) and demonstrated enhanced osteoblastogenesis and adipogenesis versus WT MSCs. BMP2 was also expressed at higher levels in the femurs and tibias of Aldh1a1^−/− mice with accompanying induction of BMP2-regulated responses, including expression of Runx2 and alkaline phosphatase, and Smad phosphorylation. In vitro, Rald, which accumulates in Aldh1a1^−/− mice, potently induced BMP2 in WT MSCs in a retinoic acid receptor (RAR)-dependent manner, suggesting that Rald is involved in the BMP2 increases seen in Aldh1a1 deficiency in vivo. Collectively, these data implicate Aldh1a1 as a novel determinant of cortical bone density and marrow adiposity in the skeleton in vivo through modulation of BMP signaling.

Phytoestrogens and bone health at different reproductive stages

BACKGROUND

Isoflavones are an alternative to hormonal therapy for the relief of menopausal symptoms. Since isoflavones interact with estrogen receptors it has been hypothesized that such substances may have an effect on bone health.

OBJECTIVE

To clarify the effect of isoflavones on bone at experimental and clinical level, and to identify areas that require further clarification and research.

METHOD

A systematic review of studies involving isoflavones and bone health was performed, and a specific search on isoflavone's mechanism of action and the importance of equol production was made based on Internet search engines, MEDLINE (1966-October 2012) and the Cochrane Controlled Clinical Trials Register. This search was supplemented by a handsearch of reference lists of selected papers.

RESULTS

In vitro and animal studies show a positive effect of isoflavones on bone which has not been clearly confirmed by long-term human trials. Equol producers seem to present a more positive response to isoflavone intervention. Isoflavone rich diets could help maintain peak bone mass in premenopausal women. The effect of isoflavones in perimenopausal women is insufficiently studied but it seems to attenuate bone loss in the menopausal transition. In postmenopause, isoflavones may present a modest benefit but its clinical relevance in preventing osteoporotic fractures remains to be determined.

CONCLUSIONS

The present review suggests that isoflavone increase bone mineral density and decrease the bone turnover resorption markers. The effect of soy isoflavones on BMD is mediated by equol production, reproductive status, supplement type, isoflavone dose and intervention duration.

Possible role of S-equol on bone loss via amelioration of inflammatory indices in ovariectomized mice

S-equol is a natural metabolite of the soy isoflavone, daidzein, produced by intestinal bacteria. S-equol has been shown to have greater estrogenic activity than other soy isoflavones and prevent bone loss in post-menopausal women. Estrogen regulates both bone remodeling and hemopoiesis in the bone marrow, these processes that communicate closely with each other. In this study, we investigated the effect of S-equol on bone mass and gene expression of bone marrow cells in ovariectomized (OVX) mice. Female ddY strain mice, aged 12 weeks, were either sham operated or OVX. The OVX mice were randomly divided into two groups: (1) OVX control and (2) OVX fed a 0.06% (w/w) S-equol supplemented diet. After 2 weeks, the trabecular bone volume of the femoral distal metaphysis was markedly reduced in OVX mice. However, treatment with equol was observed to ameliorate this. Expression of inflammatory-, osteoclastogenesis- and adipogenesis-related genes was increased in OVX mice compared with sham mice, and equol was observed to suppress their expression. The present study demonstrates that equol might ameliorate bone loss caused by estrogen deficiency through regulating hemopoiesis and production of inflammatory cytokines in bone marrow cells.

Isoflavone metabolism and bone-sparing effects of daidzein-metabolites

Several dietary phytochemicals exhibit anti-oxidative, anti-inflammatory and anti-osteoporotic activities relevant to prevention of chronic diseases, including lifestyle-related diseases. Soybean isoflavones are similar in structure to estrogen and have received considerable attention as potential alternatives to hormone replacement therapy. Daidzein, a major isoflavone found in soybean, is metabolized to equol by intestinal microflora; this metabolite exhibits stronger estrogenic activity than daidzein. Recent studies suggest that the clinical effectiveness of isoflavones might be due to their ability to produce equol in the gut. This review focused on the metabolic pathway of equol and possible bioactivities of equol and O-desmethylangolensin, another metabolite of daidzein, with regard to bone metabolism and the status of intestinal microflora. Furthermore, we considered risk-benefit analyses of isoflavones and their metabolites.

Isoflavones suppress the expression of the FcεRI high-affinity immunoglobulin E receptor independent of the estrogen receptor

Isoflavones found in soybeans and soy products possess clinically relevant properties. However, the anti-allergic effect of isoflavones has been poorly studied. We examined the effects of isoflavones, genistein, daidzein, and equol, on the expression of the high-affinity immunoglobulin E (IgE) receptor, FcεRI, which plays a central role in IgE-mediated allergic response. Flow cytometric analysis showed that all of these isoflavones reduced the cell surface expression of FcεRI on mouse bone-marrow-derived mast cells and human basophilic KU812 cells. All isoflavones decreased the levels of the FcεRIα mRNA in the cells. Genistein reduced the mRNA expression of the β chain, and daidzein and equol downregulated that of the γ chain. The suppressive effects of isoflavones on FcεRI expression were unaffected by ICI 182,780, an estrogen receptor antagonist, suggesting that these effects were independent of estrogen receptors.

Receptor activator of nuclear factor κB ligand (RANKL) protein expression by B lymphocytes contributes to ovariectomy-induced bone loss

Production of the cytokine receptor activator of NFκB ligand (RANKL) by lymphocytes has been proposed as a mechanism by which sex steroid deficiency causes bone loss. However, there have been no studies that functionally link RANKL expression in lymphocytes with bone loss in this condition. Herein, we examined whether RANKL expression in either B or T lymphocytes contributes to ovariectomy-induced bone loss in mice. Mice harboring a conditional RANKL allele were crossed with CD19-Cre or Lck-Cre mice to delete RANKL in B or T lymphocytes, respectively. Deletion of RANKL from either cell type had no impact on bone mass in estrogen-replete mice up to 7 months of age. However, mice lacking RANKL in B lymphocytes were partially protected from the bone loss caused by ovariectomy. This protection occurred in cancellous, but not cortical, bone and was associated with a failure to increase osteoclast numbers in the conditional knock-out mice. Deletion of RANKL from T lymphocytes had no impact on ovariectomy-induced bone loss. These results demonstrate that lymphocyte RANKL is not involved in basal bone remodeling, but B cell RANKL does contribute to the increase in osteoclasts and cancellous bone loss that occurs after loss of estrogen.

Daidzein prevents the increase in CD4+CD28null T cells and B lymphopoesis in ovariectomized mice: a key mechanism for anti-osteoclastogenic effect

Estrogen deficiency leads to an upregulation of TNF-α producing T cells and B-lymphopoesis which augments osteoclastogenesis. Estrogen deficiency also increases the population of premature senescent CD4⁺ CD28null T cells which secrete a higher amount of TNF-α thus leading to enhanced osteoclastogenesis. Isoflavonoids like daidzein and genistein are found mostly in soybeans, legumes, and peas. These share structural similarity with 17β-stradiol (E2) and have osteoprotective role. This study explores the effect of daidzein (Daid) on the proliferation of TNF-α producing T cells, premature senescent T cells and B cell lymphopoesis under estrogen deficient conditions. For this study adult Balb/c mice were treated with Daid at 10 mg/kg body weight dose by oral gavage daily post ovariectomy (Ovx). After six weeks animals were autopsied and bone marrow and spleen cells were collected for FACS analysis. Blood serum was collected for ELISA. It was observed that Ovx mice treated with Daid for six weeks show reduction in Ovx induced expansion of CD4⁺ T cells in bone marrow and spleen when analysed by flow cytometry. Estrogen deficiency led to increased prevalence of TNF-α secreting CD4⁺CD28null T cells, however, treatment with Daid increased the percentage of CD4⁺CD28⁺ T cells. Co-culture of CD4⁺CD28null T cells and bone marrow resulted in enhanced osteoclastogenesis as evident by increased tartarate resistant acid phosphatase (TRAP) expression, an osteoclast marker. However, treatment with Daid resulted in reduced osteoclastogenesis in CD4⁺CD28null T cells and bone marrow cell co-culture. Daid also regulated B lymphopoesis and decreased mRNA levels of RANKL in B220⁺ cells. Taken together, we propose that one of the mechanisms by which Daid prevents bone loss is by reversing the detrimental immune changes as a result of estrogen deficiency.

Comparison of three thermostable β-glucosidases for application in the hydrolysis of soybean isoflavone glycosides

A novel thermostable β-glucosidase (Te-BglA) from Thermoanaerobacter ethanolicus JW200 was cloned, characterized and compared for its activity against isoflavone glycosides with two β-glucosidases (Tm-BglA, Tm-BglB) from Thermotoga maritima. Te-BglA exhibited maximum hydrolytic activity toward pNP-β-d-glucopyranoside (pNPG) at 80 °C and pH 7.0, was stable for a pH range of 4.6-7.8 and at 65 °C for 3 h, and had the lowest K(m) for the natural glycoside salicin and the highest relative substrate specificity (k(cat)/K(m))((salicin))/(k(cat)/K(m))((pNPG)) among the three enzymes. It converted isoflavone glycosides, including malonyl glycosides, in soybean flour to their aglycons more efficiently than Tm-BglA and Tm-BglB. After 3 h of incubation at 65 °C, Te-BglA produced complete hydrolysis of four isoflavone glycosides (namely, daidzin, genistin and their malonylated forms), exhibiting higher productivity of genistein and daidzein than the other two β-glucosidases. Our results suggest that Te-BglA is preferable to Tm-BglA and Tm-BglB, but all three enzymes have great potential applications in converting isoflavone glycosides into their aglycons.

The effects of native and synthetic estrogenic compounds as well as vitamin D less-calcemic analogs on adipocytes content in rat bone marrow

BACKGROUND

We demonstrated previously that phytoestrogens and vitamin D analogs like estradiol-17β (E2) modulate bone morphology in rat female model.

AIM

We now analyze the effects of phytoestrogens, E2, selective E2 re ceptor modulators, and the less-calcemic analogs of vitamin D: JKF1624F2-2 (JKF) or QW1624F2-2 (QW) on fat content in bone marrow (BM) from long bones in ovariectomized female rats (OVX).

MATERIALS AND METHODS

OVX rats were injected with treatments known to affect bone formation, 5 days per week for 2.5 month for analysis of fat content in BM.

RESULTS

In OVX young adults there is a decreased bone formation and a 10-fold increase in fat cells content in BM. Treatment with E2, raloxifene (Ral) or DT56a resulted in almost completely abolishment of fat cells content. Daidzein (D) decreased fat cells content by 80%, genistein (G) or biochainin A (BA) did not change fat cells content and carboxy BA (cBA) had a small but significant effect. JKF or QW did not affect fat cells content, whereas combined treatment of JKF or QW with E2 resulted in complete abolishment of fat cells content. These changes in fat cells content are inversely correlated with changes in bone formation.

CONCLUSIONS

Our results demonstrate that adipogenesis induced by OVX is a reversible process which can be corrected by hormonal treatments. The awareness of a relationship between fat and bone at the marrow level might provide a better understanding of the pathophysiology of bone loss as well as a novel approach to diagnosis and treatment of postmenopausal osteoporosis.

Genistein and a soy extract differentially affect three-dimensional bone parameters and bone-specific gene expression in ovariectomized mice

Soy isoflavone preparations, such as purified genistein and a soy extract (Novasoy), were reported previously to exert beneficial effects on bones. Our purpose in this study was to compare the effects of genistein and Novasoy on 3-dimensional trabecular bone parameters and the expression of bone-specific genes in ovariectomized (OVX) mice. The sham-operated mice were fed the control diet and OVX mice were fed diets containing genistein or Novasoy or the control diet, with or without 17beta-estradiol treatment, for 5 wk. Trabecular bone parameters of tibias were measured by microcomputed tomography and gene expression was assayed by real-time PCR. Consumption of diets containing genistein or Novasoy partially prevented the ovariectomy-induced increase in body weight but did not alter the uterus weight of the OVX mice. Novasoy, but not purified genistein, significantly preserved trabecular bone mass, bone volume, and trabecular bone separation in the proximal tibial metaphysis. Purified genistein decreased mRNA expression of receptor activator of nuclear factor-kappaB ligand (RANKL), carbonic anhydrase II, and cathepsin K and enhanced the ratio of osteoprotegrin:RANKL mRNA expression in the tibial head of the OVX mice. In contrast, the diet containing Novasoy suppressed the OVX-induced increase in serum alkaline phosphatase but did not alter bone-specific gene expression of tibia. Our study demonstrated that a soy extract containing a similar level of genistein in the form of Novasoy is more effective than purified genistein in improving tibial trabecular bone quality in OVX mice, but the mechanism of action might be distinct from that of genistein.

A longitudinal study of the effect of genistein on bone in two different murine models of diminished estrogen-producing capacity

This experiment was designed to assess the capacity of dietary genistein (GEN), to attenuate bone loss in ovariectomized (OVX) and ovary-intact VCD-treated mice. Pretreatment of mice with 4-vinylcyclohexene diepoxide (VCD) gradually and selectively destroys ovarian follicles whilst leaving ovarian androgen-producing cells largely intact. VCD induces a perimenopause-like condition prior to the onset of reproductive acyclicity. Sixteen-week-old C57BL/6J mice were randomized to five treatment groups: sham(SHM), OVX, SHM + VCD, OVX + GEN, and SHM + VCD + GEN. In vivo, blood samples were drawn for hormone and isoflavone analyses, estrous cycles were monitored, and X-ray imaging was performed to assess changes in bone parameters. Following sacrifice, ovaries were assessed histologically, bone microarchitecture was evaluated via microcomputed tomography, and bone mechanical properties were measured. Some effects of GEN were observed in OVX mice, but GEN effects were not able to be evaluated in VCD-treated mice due to the subtle diminution of bone during the 4 months of this experiment.

Oral bovine lactoferrin improves bone status of ovariectomized mice

The aim of the present study was to evaluate the effect of dietary lactoferrin on bone metabolism in vivo using a postmenopausal animal model. We investigated whether bovine lactoferrin (bLF) ingestion could prevent bone loss in ovariectomized mice. Twelve-week-old female C3H mice either ovariectomized or sham operated were fed for 27 wk with the control diet (AIN-93M with 140 g of total milk protein as a protein source per kg of diet). Four groups of ovariectomized mice received diets including different concentrations of bLF (1, 5, 10, or 20 g of total milk protein were replaced by bLF). Ovariectomy induced a decreased uterine weight and a smaller gain of bone mineral density. Immunoreactive bLF was detected in the peripheral blood, and its concentration was related to the amount of bLF ingestion. bLF supplementation to the diet improved bone mineral density (BMD) and femoral failure load in a dose-dependent manner. We confirmed the direct effects of bLF in vitro using established and primary cultures of murine bone cells. Addition of bLF to the culture medium at a concentration of between 1 and 1,000 microg/ml stimulated both cell growth and differentiation of osteoblastic MC3T3 cells while inhibiting the growth of preosteoclastic RAW 267.4 cells. In primary culture of mixed bone cells, an enhanced osteoblast differentiation was associated with an inhibition of osteoclast differentiation at lower bLF concentrations (1-10 microg/ml). In conclusion, these findings suggest that dietary lactoferrin supplementation can have a beneficial effect on postmenopausal bone loss by modulating bone formation and resorption.

Inhibition of adipocyte differentiation by phytoestrogen genistein through a potential downregulation of extracellular signal-regulated kinases 1/2 activity

In the current study, we investigated the effects of genistein on adipogenic differentiation of mouse bone marrow-derived mesenchymal stem cell (BMSC) cultures and its potential signaling pathway. The terminal adipogenic differentiation was assessed by western-blotting analysis of adipogenic-specific proteins such as PPARgamma, C/EBPalpha, and aP2 and the formation of adipocytes. Treatment of mouse BMSC cultures with adipogenic cocktail resulted in sustained activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), which are members of the mitogen-activated protein kinase (MAPK) family, at the early phase of adipogenesis (from days 3 to 9). Inhibition of ERK1/2 activation by PD98059, a specific MEK inhibitor, reversed the induced adipogenic differentiation. Genistein dose-dependently decreased the phosphorylation of ERK1/2 in mouse BMSC cultures. Genistein incubation for the entire culture period, as well as that applied during the early phase of the culture period, significantly inhibited the adipogenic differentiation of mouse BMSC cultures. While genistein was incubated at the late stage (after day 9), no inhibitory effect on adipogenic differentiation was observed. BMSC cultures treated with genistein in the presence of fibroblast growth factor-2 (FGF-2), an activator of the ERK1/2 signaling pathway, expressed normal levels of ERK1/2 activity, and, in so doing, are capable of undergoing adipogenesis. Our results suggest that activation of the ERK1/2 signaling pathway during the early phase of adipogenesis (from days 3 to 9) is essential to adipogenic differentiation of BMSC cultures, and that genistein inhibits the adipogenic differentiation through a potential downregulation of ERK1/2 activity at this early phase of adipogenesis.