Boron Supplementation Promotes Osteogenesis of Tibia by Regulating the Bone Morphogenetic Protein-2 Expression in African Ostrich Chicks

Boric acid and Molybdenum trioxide synergistically stimulate osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells

INTRODUCTION

Metals and their metal ions have been shown to exhibit certain biological functions that make them attractive for use in biomaterials, for example in bone tissue engineering (BTE) applications. Recent data shows that Molybdenum (Mo) is a potent inducer of osteogenic differentiation in human bone marrow-derived mesenchymal stromal cells (BMSCs). On the other hand, while boron (B) has been shown to enhance vascularization in BTE applications, its impact on osteogenic differentiation is volatile: while improved osteogenic differentiation has been described, other data show that B might slow down osteogenic differentiation or reduce the calcification of the extracellular matrix (ECM) when applied in higher doses. Still, the combination of pro-osteogenic Mo and pro-angiogenic B is certainly attractive in the context of biomaterials intended for the use in BTE.

METHODS

Therefore, the combined effect of molybdenum trioxide and boric acid at different ratios was investigated in this study to evaluate the effects on the viability, proliferation, osteogenic differentiation, ECM production and maturation of BMSCs.

RESULTS

Mo ions proved to be stronger osteoinductive compared to B, in fact, while some osteogenic differentiation markers were downregulated in the presence of B, the presence of Mo provided compensation. The combined application of B and Mo indicated a combination of individual effects, partially even enhancing the expected combined performance of the single stimulations.

CONCLUSIONS

The combination of B and Mo might be beneficial for BTE applications since the limited osteogenic properties of B can be compensated by Mo. Furthermore, since B is known to be pro-angiogenic, the combination of both substances may synergistically lead to improved vascularization and bone regeneration. Future studies should assess the angiogenic performance of this combination in greater detail.

Osteogenic Differentiation Capacity of Dental Pulp Stem Cells on 3D Printed Polyurethane/Boric Acid Scaffold

Additive manufacturing is growing in the area of dentistry and orthopedics due to the potential for the fabrication of individual implants. In this study, fused deposition modeling which is the most popular method was used to produce 3D scaffolds having a grid pattern from the polyurethane (PU) filament. Then, this scaffold was coated with boric acid (BA) with the thermionic vacuum arc technique. The microstructure analysis showed the macro-pores having a dimension of ~ 0.16 mm2. The BA coating increased the roughness in adverse decreased the wettability. The presence of BA on the scaffold before and after cell culture was confirmed by FESEM-EDS and ATR-FTIR. The Cell proliferation and osteogenic differentiation capacity of dental pulp stem cells (DPSCs) on uncoated and coated printed 3D PU scaffolds were also investigated. On the third day, cell viability was found to be higher (1.3-fold) in the groups containing BA. However, on the seventh day, the increase in cell proliferation in the PU+BA group was found to be less than in the other groups. According to Ca deposition analysis and Alizarin Red staining, PU+BA increased the calcium accumulation in the cells in both osteogenic induced and non-induced conditions at day 14. According to gene expression analysis, the Runx2 expression was not detected in PU+BA groups with and without differentiation medium (p ≤0.05). The expression of OCN was persistently increased up to 21-fold and 48-fold in cells on PU and PU+BA in osteogenic differentiation medium group after 14 days compared to control group (p ≤0.05). DSPP expression was observed only in PU+BA in osteogenic differentiation medium group. In line with the results that we have obtained, our 3D printed scaffolds have properties to trigger the differentiation of DPSCs cells in terms of osteogenicity.

PI3K/Akt signaling pathway mediates the effect of low-dose boron on barrier function, proliferation and apoptosis in rat intestinal epithelial cells

Boron is an essential trace element with roles in growth, development, and physiological functions; however, its mechanism of action is still unclear. In this study, the regulatory roles of the PI3K/Akt signaling pathway on boron-induced changes in barrier function, proliferation, and apoptosis in rat intestinal epithelial cells were evaluated. Occludin levels, the proportion of cells in the G2/M phase, cell proliferation rate, and mRNA and protein expression levels of PCNA were higher, while the proportions of cells in the G0/G1 and S phases, apoptosis rate, and caspase-3 mRNA and protein expression levels were lower in cells treated with 0.8 mmol/L boron than in control IEC-6 cells (P < 0.01 or P < 0.05). However, 40 mmol/L boron decreased ZO-1 and Occludin levels, the proportion of cells in the G2/M phase, cell proliferation rate, and mRNA and protein levels of PCNA and increased the apoptosis rate and caspase-3 mRNA expression (P < 0.01 or P < 0.05). After specifically blocking PI3K and Akt signals (using LY294002 and MK-2206 2HCL), 0.8 mmol/L boron had no effects on Occludin, PCNA level, apoptosis rates, and caspase-3 levels (P < 0.05); however, the proliferation rate and PCNA levels decreased significantly (P < 0.01 or P < 0.05). The addition of 40 mmol/L boron did not affect ZO-1 and Occludin levels and did not affect the apoptosis rate or PCNA and caspase-3 levels. These results suggested that the PI3K/Akt signaling pathway mediates the effects of low-dose boron on IEC-6 cells.

Boron enhances adaptive responses and biological performance via hormetic mechanisms

Boron is shown in the present review to induce hormetic dose responses in a broad range of biological models, organ systems and endpoints. Of particular importance is that numerous hormetic findings have been reported with whole animal studies, with extensive dose response evaluations with the optimal dosing being similar across multiple organ systems. These findings appear to be underappreciated and suggest that boron may have clinically significant systemic effects beyond that of its putative and more subtle essentiality functions. The re-exploration of boron's bioactivity as seen through hormetic mechanisms may also underscore the value of this approach to the assessment of micronutrient effects in human health and disease.

Zebrafish as a Model to Unveil the Pro-Osteogenic Effects of Boron-Vitamin D3 Synergism

The micronutrient boron (B) plays a key role during the ossification process as suggested by various in vitro and in vivo studies. To deepen our understanding of the molecular mechanism involved in the osteogenicity of B and its possible interaction with vitamin D3 (VD), wild-type AB zebrafish (Danio rerio) were used for morphometric analysis and transcriptomic analysis in addition to taking advantage of the availability of specific zebrafish osteoblast reporter lines. First, osteoactive concentrations of B, VD, and their combinations were established by morphometric analysis of the opercular bone in alizarin red-stained zebrafish larvae exposed to two selected concentrations of B (10 and 100 ng/ml), one concentration of VD (10 pg/ml), and their respective combinations. Bone formation, as measured by opercular bone growth, was significantly increased in the two combination treatments than VD alone. Subsequently, a transcriptomic approach was adopted to unveil the molecular key regulators involved in the synergy. Clustering of differentially expressed genes revealed enrichment toward bone and skeletal functions in the groups co-treated with B and VD. Downstream analysis confirmed mitogen-activated protein kinase as the most regulated pathway by the synergy groups in addition to transforming growth factor-β signaling, focal adhesion, and calcium signaling. The best-performing synergistic treatment, B at 10 ng/ml and VD at 10 pg/ml, was applied to two zebrafish transgenic lines, Tg(sp7:mCherry) and Tg(bglap:EGFP), at multiple time points to further explore the results of the transcriptomic analysis. The synergistic treatment with B and VD induced enrichment of intermediate (sp7+) osteoblast at 6 and 9 days post fertilization (dpf) and of mature (bglap +) osteoblasts at 15 dpf. The results obtained validate the role of B in VD-dependent control over bone mineralization and can help to widen the spectrum of therapeutic approaches to alleviate pathological conditions caused by VD deficiency by using low concentrations of B as a nutritional additive.