The antibacterial and angiogenic effect of magnesium oxide in a hydroxyapatite bone substitute

Abstract

Bone graft infections are serious complications in orthopaedics and the growing resistance to antibiotics is increasing the need for antibacterial strategies. The use of magnesium oxide (MgO) is an interesting alternative since it possesses broad-spectrum antibacterial activity. Additionally, magnesium ions also play a role in bone regeneration, which makes MgO more appealing than other metal oxides. Therefore, a bone substitute composed of hydroxyapatite and MgO (HAp/MgO) spherical granules was developed using different sintering heat-treatment cycles to optimize its features. Depending on the sintering temperature, HAp/MgO spherical granules exhibited distinct surface topographies, mechanical strength and degradation profiles, that influenced the in vitro antibacterial activity and cytocompatibility. A proper balance between antibacterial activity and cytocompatibility was achieved with HAp/MgO spherical granules sintered at 1100 ºC. The presence of MgO in these granules was able to significantly reduce bacterial proliferation and simultaneously provide a suitable environment for osteoblasts growth. The angiogenic and inflammation potentials were also assessed using the in vivo chicken embryo chorioallantoic membrane (CAM) model and the spherical granules containing MgO stimulated angiogenesis without increasing inflammation. The outcomes of this study evidence a dual effect of MgO for bone regenerative applications making this material a promising antibacterial bone substitute.

Mechanical and Biological Properties of Magnesium- and Silicon-Substituted Hydroxyapatite Scaffolds

“…HA-Mg and HA-Si showed almost similar weight loss around 1.8%. These results imply that Mg and Si ion substitution does not alter the biostability of scaffolds much, since the amount of substitution is very less compared to other works [26][27][28]. To evaluate the biostability, the synthesized scaffolds were immersed in Tris-HCl at 37 °C for different time intervals of 3, 7, 14 and 28 days of immersion.…”

Nano artificial periosteum PLGA/MgO/Quercetin accelerates repair of bone defects through promoting osteogenic − angiogenic coupling effect via Wnt/ β-catenin pathway

“…Therefore, well-designed artificial periosteum should have the coupling effect of “osteogenesis-angiogenesis”. Some magnesium-containing scaffolds also confirmed the promoting effect of “osteogenesis-angiogenesis” coupling on bone regeneration [ 9 , 16 , 40 ]. A sustainable releasing of Mg 2+ was proved in artificial periosteum we constructed in this project.…”

“…PLGA scaffolds with magnesium oxide (MgO) promoted osteogenesis by sustained release of Mg 2+ [ [12] , [13] , [14] ]. MgO nanoparticles have also been shown to promote bone regeneration and angiogenesis [ 15 , 16 ].…”

Effects of Zinc, Magnesium, and Iron Ions on Bone Tissue Engineering

“…94 Coelho et al showed a significant increase in the number of newly formed vessels at the implantation sites of HAp/MgO spherical granules as compared to pure HAp granules. 95 The mechanism of how magnesium promotes angiogenesis has been studied by Gu et al They found that Mg ions could stimulate proliferation and migration of endothelial cells through G protein-coupled receptor pathway. Mg ions entered into the endothelial cells by caveolin-1-mediated endocytosis, diminishing the level of caveolin-1 and enhancing the activity of eNOS, which promoted angiogenesis.…”

“…Angiogenesis plays an important role in bone tissue’s maturation process and development, and in this process, the vascular endothelial growth factor (VEGF) acts as an important mediator. , Yoshizawa et al found that 10 mM MgSO 4 could enhance the expression of VEGF in BMSCs through stimulation of both HIF-1α and HIF-2α . Coelho et al showed a significant increase in the number of newly formed vessels at the implantation sites of HAp/MgO spherical granules as compared to pure HAp granules . The mechanism of how magnesium promotes angiogenesis has been studied by Gu et al They found that Mg ions could stimulate proliferation and migration of endothelial cells through G protein-coupled receptor pathway.…”