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Background Epidemiological studies have suggested an association between selenium (Se) and diabetes mellitus (DM). However, different studies have reported conflicting results. Therefore, we performed a comprehensive meta-analysis to clarify the impact of Se on DM. Methods We searched the PubMed database for studies on the association between Se and DM from inception to June 2018. Results Twenty articles evaluating 47,930 participants were included in the analysis. The meta-analysis found that high levels of Se were significantly associated with the presence of DM (pooled odds ratios [ORs], 1.88; 95% confidence interval [CI], 1.44 to 2.45). However, significant heterogeneity was found ( I 2 =82%). Subgroup analyses were performed based on the Se measurement methods used in each study. A significant association was found between high Se levels and the presence of DM in the studies that used blood (OR, 2.17; 95% CI, 1.60 to 2.93; I 2 =77%), diet (OR, 1.61; 95% CI, 1.10 to 2.36; I 2 =0%), and urine (OR, 1.49; 95% CI, 1.02 to 2.17; I 2 =0%) as samples to estimate Se levels, but not in studies on nails (OR, 1.24; 95% CI, 0.52 to 2.98; I 2 =91%). Because of significant heterogeneity in the studies with blood, we conducted a sensitivity analysis and tested the publication bias. The results were consistent after adjustment based on the sensitivity analysis as well as the trim and fill analysis for publication bias. Conclusion This meta-analysis demonstrates that high levels of Se are associated with the presence of DM. Further prospective and randomized controlled trials are warranted to elucidate the link better.

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ObjectivesOsteoporosis is a disease of bones that is thought to result from an imbalance between bone resorption and bone formation. Although osteoporosis itself has no symptoms, osteoporosis caused by osteoclasts leads to an increased risk of fracture. Here we examined the effects of cornus officinalis on receptor activator of nuclear factor-kappaB ligand (RANKL)-mediated osteoclast differentiation.MethodsWe evaluated the effects of cornus officinalis on RANKL-induced osteoclast differentiation from bone marrow-derived macrophages (BMMs) and performed a cytotoxicity assay, reverse transcriptase-polymerase chain reaction (RT-PCR), and Western blot analysis.ResultsCornus officinalis significantly inhibits RANKL-mediated osteoclast differentiation in a dose-dependent manner, but without cytotoxicity against BMMs. The mRNA expression of tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), c-Fos, and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) in BMMs treated with RANKL was considerably inhibited by cornus officinalis treatment. Also, cornus officinalis inhibits the protein expression of c-Fos and NFATc1. Cornus officinalis greatly inhibits RANKL-induced phosphorylation of p38 and c-JUN N-terminal kinase (JNK). Also, cornus officinalis significantly suppresses RANKL-induced degradation of I-κB.ConclusionsTaken together, our results suggest that cornus officinalis may be a useful the treatment of osteoporosis.

Based on an inhibitory activity-guided fractionation for the high glucose-induced proliferation of glomerular mesangial cells (GMCs), chloroform extracts of the roots of Phytolacca americana were found to contain alpha-spinasterol (C (29)H (48)O), a delta (7)-sterol. This phytosterol proved to be a potent inhibitor (IC (50) = 3.9 x 10 (-12) g/mL, 9.5 pmol/L) of glomerular mesangial cell proliferation caused by high-ambient glucose (5.6 mM vs. 25 mM), and its inhibitory potency was about 1,000 times higher than that of simvastatin, an HMG-CoA reductase inhibitor used as a positive control. alpha-Spinasterol also significantly reduced the increases of serum triglycerides, renal weight and urinary protein excretion in streptozotocin-induced diabetic mice, and these were comparable to the results observed in insulin-treated diabetic mice. Therefore, the results obtained in this study suggest that alpha-spinasterol has a significant therapeutic potential to modulate the development and/or progression of diabetic nephropathy.

Dendrobium moniliforme (DM) is a well-known plant-derived extract that is widely used in Oriental medicine. DM and its chemical constituents have been reported to have a variety of pharmacological effects, including anti-oxidative, anti-inflammatory, and anti-tumor activities; however, no reports discuss the beneficial effects of DM on bone diseases such as osteoporosis. Thus, we investigated the relationship between DM and osteoclasts, cells that function in bone resorption. We found that DM significantly reduced receptor activator of nuclear factor kappa-B ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP)-positive osteoclast formation; DM directly induced the down-regulation of c-Fos and nuclear factor of activated T cells c1 (NFATc1) without affecting other RANKL-dependent transduction pathways. In the later stages of osteoclast maturation, DM negatively regulated the organization of filamentous actin (F-actin), resulting in impaired bone-resorbing activity by the mature osteoclasts. In addition, micro-computed tomography (µ-CT) analysis of the murine model revealed that DM had a beneficial effect on lipopolysaccharide (LPS)-mediated bone erosion. Histological analysis showed that DM attenuated the degradation of trabecular bone matrix and formation of TRAP-positive osteoclasts in bone tissues. These results suggest that DM is a potential candidate for the treatment of metabolic bone disorders such as osteoporosis.

Costunolide, a sesquiterpene lactone, exhibits anti-inflammatory and anti-oxidant properties and mediates apoptosis. However, its effects and mechanism of action in osteoclasts remain unknown. Herein, we found that costunolide significantly inhibited RANKL-induced BMM differentiation into osteoclasts in a dose-dependent manner without affecting cytotoxicity. Costunolide did not regulate the early signaling pathways of RANKL, including the mitogen-activated protein kinase and NF-κB pathways. However, costunolide suppressed nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) expression via inhibition of c-Fos transcriptional activity without affecting RANKL-induced c-Fos expression. The inhibitory effects of costunolide were rescued by overexpression of constitutively active (CA)-NFATc1. Taken together, our results suggest that costunolide inhibited RANKL-induced osteoclast differentiation by suppressing RANKL-mediated c-Fos transcriptional activity.

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