The mechanism of anti-osteoporosis effects of 3-hydroxybutyrate and derivatives under simulated microgravity

Bone scaffolds loaded with siRNA-Semaphorin4d for the treatment of osteoporosis related bone defects

Osteoporosis is a prominent disorder affecting over 200 million people worldwide. Recently, semaphorins have been implicated in the cell-cell communication between osteoclasts and osteoblasts and have been associated with the progression of osteoporosis. Previously, we demonstrated that knockdown of semaphorin4d (Sema4d) using siRNA delivered with a bone-targeting system prevented bone loss in an osteoporotic animal model. Here, we used this bone-specific technology containing siRNA-Sema4d and fabricated a PLLA scaffold capable of enhancing bone repair following fracture. We investigated the ability of the implant to release siRNA-Sema4d into the surrounding tissues over time and to influence new bone formation in a 3 mm femur osteoporotic defect model in ovariectomized rats. Delivery of the bone-targeting system released from PLLA scaffolds began 2 hours post-implantation, peaked at 1 day, and was sustained over a 21 day period. μCT analysis demonstrated a significantly higher bone volume/total volume bone mineral density and number of osteoblasts in the rats that were transplanted with scaffolds loaded with siRNA-Sema4d. These results confirm the specific role of Sema4d in bone remodeling and demonstrate that significant increases in the speed and quality of new bone formation occur when siRNA-Sema4d is delivered via a PLLA scaffold.

Isolation and characterization of side population cells from the human ovarian cancer cell line SK-OV-3

Ovarian cancer (OC) is the most malignant type of gynecological tumor due to its high recurrence rate following initial treatment. Previous studies have indicated that cancer stem cells (CSCs) may be a potential cause underlying the high proportion of recurrence. Side population (SP) cells isolated from cancer cell lines have been shown to exhibit characteristics associated with CSCs, but studies on SP cells in human ovarian SK-OV-3 cell line are limited. In the present study, the SP cell fraction (4.83% of the total cell population) was isolated using flow cytometry, and analyzed by immunocytochemical analysis and reverse transcription-quantitative polymerase chain reaction. The results showed that SP cells exhibited a high mean fluorescence intensity for CD44, a CSC marker, in addition to elevated expression of the CSCs-associated genes, ATP-binding cassette sub-family G member 2 and Nestin. These findings indicated the stem cell-like features of the SP cells. Furthermore, a colony formation test showed that the isolated SP cells possessed a marked capacity for self-regeneration and proliferation. In addition, a cell cycle assay involving cisplatin indicated that the SP cells were strongly resistant to chemotherapy. In conclusion, the present results suggested that SP cells isolated from the SK-OV-3 cell line exhibited properties typically associated with CSCs. Therefore, the isolated SP cells may be used to provide novel insight into potential therapies against OC.

Effects of Curculigoside on Memory Impairment and Bone Loss via Anti-Oxidative Character in APP/PS1 Mutated Transgenic Mice

Alzheimer's disease (AD) and osteoporosis are two closely related multifactorial progressively degenerative diseases that predominantly affect aged people. These two diseases share many common risk factors, including old age, being female, smoking, excessive drinking, low estrogen, and vitamin D3 levels. Additionally, oxidative damage and the dysfunction of the antioxidant system play important roles in the pathogenesis of osteoporosis and AD. Aβ not only leads to impaired memory but also plays a crucial role in the demineralization process of bone tissues of older people and women with menopause. Curculigoside can promote calcium deposition and increase the levels of ALP and Runx2 in osteoblasts under oxidative stress via anti-oxidative character. Therefore, we investigated the effects of CUR on the spatial learning and memory by the Morris water maze and brain immunohistochemistry, and bone microstructure and material properties of femurs by micro-computed tomography and mechanical testing in APP/PS1 mutated transgenic mice. Oral administration of CUR can significantly enhance learning performance and ameliorate bone loss in APP/PS1 mutated transgenic mice, and the mechanism may be related to its antioxidant effect. Based on these results, CUR has real potential as a new natural resource for developing medicines or dietary supplements for the prevention and treatment of the two closely linked multifactorial progressive degenerative disorders, AD and osteoporosis.

Effects of dietary resveratrol on excess-iron-induced bone loss via antioxidative character

Estrogen deficiency has been considered to be a major cause of osteoporosis, but recent epidemiological evidence and mechanistic studies have indicated that aging and the associated increase in reactive oxygen species (ROS) are the proximal pathogenic factors. Through ROS-mediated reactions, iron can induce disequilibrium of oxidation and antioxidation and can cause bone loss in mice. Therefore, we investigated the effects of resveratrol (RES) on bone mineral density, bone microstructure and the osteoblast functions under iron-overload conditions. Excess iron disrupted the antioxidant/prooxidant equilibrium of the mice and induced the defect and the lesion of the bone trabecula as well as disequilibrium between bone formation and bone resorption in iron-overload mice. Oral administration of RES significantly prevented bone loss in the osteoporotic mice. RES reversed the reduction of Runx2, OCN and type I collagen from excess iron; up-regulated the level of FOXO1; and maintained the antioxidant/prooxidant equilibrium in the mice. RES also reduced the ratio of OPG/RANKL in MC3T3-E1 cells and in mice and significantly inhibited subsequent osteoclastogenesis. These results provide new insights into the antiosteoporosis mechanisms of RES through antioxidative effects, suggesting that RES can be considered a potential natural resource for developing medicines or dietary supplements to prevent and treat osteoporosis.