Dietary Silicon Deficiency Does Not Exacerbate Diet-Induced Fatty Lesions in Female ApoE Knockout Mice

Effects of Silicon Compounds on Biomineralization, Osteogenesis, and Hard Tissue Formation

Bioinspired stem cell-based hard tissue engineering includes numerous aspects: The synthesis and fabrication of appropriate scaffold materials, their analytical characterization, and guided osteogenesis using the sustained release of osteoinducing and/or osteoconducting drugs for mesenchymal stem cell differentiation, growth, and proliferation. Here, the effect of silicon- and silicate-containing materials on osteogenesis at the molecular level has been a particular focus within the last decade. This review summarizes recently published scientific results, including material developments and analysis, with a special focus on silicon hybrid bone composites. First, the sources, bioavailability, and functions of silicon on various tissues are discussed. The second focus is on the effects of calcium-silicate biomineralization and corresponding analytical methods in investigating osteogenesis and bone formation. Finally, recent developments in the manufacturing of Si-containing scaffolds are discussed, including in vitro and in vivo studies, as well as recently filed patents that focus on the influence of silicon on hard tissue formation.

Synthesis, mechanical properties and corrosion behavior of powder metallurgy processed Fe/Mg2Si composites for biodegradable implant applications

Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg₂Si particles were proposed. The initial powders were prepared by different combinations of mixing and milling processes, and finally consolidated by hot rolling. The influence of the microstructure on mechanical properties and corrosion behavior of Fe/Mg₂Si was investigated. Scanning electron microscopy and X-ray diffraction were used for the assessment of the composite structure. Tensile and hardness tests were performed to characterize the mechanical properties. Potentiodynamic and static corrosion tests were carried out to investigate the corrosion behavior in a pseudo-physiological environment. Samples with smaller Mg₂Si particles showed a more homogenous distribution of the reinforcement. Yield and ultimate tensile strength increased when compared to those of pure Fe (from 400MPa and 416MPa to 523MPa and 630MPa, respectively). Electrochemical measurements and immersion tests indicated that the addition of Mg₂Si could increase the corrosion rate of Fe even twice (from 0.14 to 0.28mm·year^-1). It was found that the preparation method of the initial composite powders played a major role in the corrosion process as well as in the corrosion mechanism of the final composite.

Lowering effects of aspirin eugenol ester on blood lipids in rats with high fat diet

BACKGROUND

Aspirin and eugenol were esterified to synthesize aspirin eugenol ester (AEE). As a pale yellow and odourless crystal, AEE reduced the gastrointestinal damage of aspirin and vulnerability of eugenol. The study was conducted to evaluate the preventive effects of AEE on blood lipids in rats with high fat diet (HFD).

METHODS

Suspensions of AEE and simvastatin were prepared in 5% carboxymethyl cellulose sodium (CMC-Na). In order to observe the intervention effects, the drugs and HFD were administrated at the same time. Based on individual weekly body weight (BW), AEE was intragastrically administrated at the dosage of 18, 36 and 54 mg/kg. Simvastatin (10 mg/kg) and CMC-Na (20 mg/kg) were used as control drug. After 6 weeks of administration, the changes of BW and blood lipid indices including triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL) and total cholesterol (TCH) were determined in the experiment.

RESULTS

The rat blood lipids profile in model group was remarkably different after feeding 6-weeks HFD. TG, TCH and LDL indexes in model group were increased significantly compared with those in control group (p < 0.01). AEE at the dosage of 54 mg/kg significantly decreased levels of TG, TCH and LDL (p < 0.01), and slowed the rate of BW gain in comparison with model group (p < 0.05). Moreover, high dose AEE showed better effects than simvastatin on reducing TCH level and similar effects on TG, HDL and LDL.

CONCLUSION

AEE could remarkably reduce levels of TG, TCH and LDL in rats with high fat diet, and slow the rate of body weight gain. It was conducted that AEE was a potential candidate on reducing blood lipids level. The mechanism of action of AEE should be investigated in further studies.

Arterial Stiffness and Trace Elements in Apparently Healthy Population- A Cross-sectional Study

INTRODUCTION

Stiffening of arteries is a natural ageing process. Any diseases/disorders or risk factors that escalate oxidative stress, microvascular inflammation and endothelial damage may promote to premature vascular stiffening. Any imbalance in these trace element levels may independently contribute to the changes in the components in the arterial wall and thus, arterial stiffness via one or more mechanisms.

AIM

To evaluate the severity of arterial stiffness in apparently healthy population and also to evaluate role of various risk factors and trace elements in the severity of arterial stiffness.

MATERIALS AND METHODS

Male and female subjects living in urban and rural areas of Nellore district, Andhra Pradesh, India, between 20-60 years, apparently normal as judged by the clinician basing on clinical and laboratory findings, were studied. Carotid-Femoral Pulse Wave Velocity (cf-PWV) a marker of arterial stiffness was assessed using non-invasive blood pressure curve monitoring (periscope). Furthermore, we also estimated serum levels of Copper (Cu), Zinc (Zn), Selenium (Se), chromium (Cr), Aluminium (Al), silicon (Si), Manganese (Mn), Molybdenum (Mb), Vanadium (Vn) and lead (Pb) using atomic absorption spectrophotometer. ANOVA and Chi-Square test were used to study the clinical correlations between severity of arterial stiffness, risk factors and trace elements.

RESULTS

A total of 737 apparently healthy subjects participated in this cross-sectional study. Of the total 542 (73.5%) were from rural and the remaining 195 (26.5%) were living in urban areas, 328 (44.5%) were males, and 409 (55.5%) were females. A 63.5% (468/737) had normal arterial stiffness followed by 14.5% (107/737) with mild stiffness, 7% (57/737) had moderate stiffness and 14.2% (105/737) had severe arterial stiffness. Smoking, alcohol, blood pressures, fasting blood sugar, and total cholesterol, Cu, Al and Vn correlated (p<0.05) with different grades of arterial stiffness.

CONCLUSION

A 36.5% had high arterial stiffness despite being apparently healthy. Smoking, alcohol, blood pressures, fasting blood sugars, and total cholesterol, Cu, Al and Vn could have contributed for such an abnormality. Caution has to be executed while understanding the study results since the pathophysiological process is complex.