METHODS: A case-control study was nested in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 2008 incident invasive breast cancer cases (estrogen receptor (ER)+, n = 1622; ER-, n = 386), matched 1:1 to controls, were included in the analysis. Women were predominantly postmenopausal at blood collection (77%); postmenopausal women included users and non-users of postmenopausal hormone therapy (HT). Serum OPG was quantified with an electrochemiluminescence assay. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression.

RESULTS: The associations between OPG and ER+ and ER- breast cancer differed significantly. Higher concentrations of OPG were associated with increased risk of ER- breast cancer (top vs. bottom tertile RR = 1.93 [95% CI 1.24-3.02]; p trend = 0.03). We observed a suggestive inverse association for ER+ disease overall and among women premenopausal at blood collection. Results for ER- disease did not differ by menopausal status at blood collection (p het = 0.97), and we observed no heterogeneity by HT use at blood collection (p het ≥ 0.43) or age at breast cancer diagnosis (p het ≥ 0.30).

METHODS: The osteogenic potential of the OPG-chitosan gel was evaluated in rabbits. Critical-sized defects were created in the calvarial bone, which were either left unfilled (control; group I), or filled with chitosan gel (group II) or OPG-chitosan gel (group III), with rabbits sacrificed at 6 and 12 weeks. Bone samples from the surgical area were decalcified and treated with routine histological and immunohistochemical protocols using OC, OPN, and cathepsin K (osteoclast marker) antibodies. The toxicity of the OPG-chitosan gel was evaluated by biochemical assays (liver and kidney function tests).

METHODS: Thirty-two female Wistar rats were randomly divided into four groups: Sham-operated (Sham), ovariectomized control (OVXC), ovariectomized with Labisia pumila var. alata (LPva) and ovariectomized with ERT (Premarin) (ERT). The LPva and ERT were administered via daily oral gavages at doses of 17.5 mg/kg and 64.5 μg/kg, respectively. Following two months of treatment, the rats were euthanized and the gene expressions of BMP-2, OPG, RANKL and MCSF in the femoral bones were measured using a branch - DNA technique.

RESULTS: The RANKL gene expression was increased while the OPG and BMP-2 gene expressions were reduced in the OVXC group compared to the SHAM group. There were no significant changes in the MCSF gene expressions among the groups. Treatment with either LPva or ERT was able to prevent these ovariectomy-induced changes in the gene expressions in ovariectomized rats with similar efficacy.

METHODS: MC3T3-E1 cells were seeded on HA and treated with recombinant IL-6 or rIL-17A or combination of the two cytokines. Cell proliferation and differentiation activity were measured by MTS and alkaline phosphatase assays respectively. Observation of cell adhesion and proliferation was examined by scanning electron microscopy. Gene and protein expressions were performed on RANKL and OPG using qPCR, Western blot and ELISA.

METHODS: Forty-two female Sprage-Dawley rats were randomized into 7 groups (6 in each group). The ovariectomized (OVX) and OVX + 6%, 3%, and 1.5% EBN and OVX +estrogen groups were given standard rat chow alone, standard rat chow +6%, 3%, and 1.5% EBN, or standard rat chow +estrogen therapy (0.2mg/kg per day), respectively. The sham-operation group was surgically opened without removing the ovaries. The control group did not have any surgical intervention. After 12 weeks of intervention, blood samples were taken for serum estrogen, osteocalcin, and osteoprotegerin, as well as the measurement of magnesium, calcium abd zinc concentrations. While femurs were removed from the surrounding muscles to measure bone mass density using the X-ray edge detection technique, then collected for histology and estrogen receptor (ER) immunohistochemistry.

RESULTS: Ovariectomy altered serum estrogen levels resulting in increased food intake and weight gain, while estrogen and EBN supplementation attenuated these changes. Ovariectomy also reduced bone ER expression and density, and the production of osteopcalcin and osteorotegerin, which are important pro-osteoplastic hormones that promote bone mineraliztion and density. Conversely, estrogen and EBN increased serum estrogen levels leading to increased bone ER expression, pro-osteoplastic hormone production and bone density (all P<0.05).