Magnesium corrosion particles do not interfere with the immune function of primary human and murine macrophages

Abstract

Magnesium is currently under investigation as a prospective biodegradable implant material. Biodegradation of magnesium causes a release of magnesium, hydroxide ions and hydrogen gas but it can also lead to the formation of particulate debris. Implant-derived particles may have immunotoxic effects. To investigate the influence of magnesium-derived particles on the immune functions of primary macrophages, up to 500 μg/ml magnesium or magnesium corrosion particles were added to the cell culture medium. No major effects were observed on cell viability and on the release of the proinflammatory cytokine tumor necrosis factor (TNF)α. In addition, the ability of macrophages to stimulate proliferation of allogenic lymphocytes in a mixed leukocyte reaction remained unaffected. When macrophages were incubated with magnesium particles and then infected with the apathogenic Mycobacterium smegmatis, infection-induced TNFα secretion from murine macrophages was inhibited but not from human macrophages. However, the bactericidal activity of either cell type was not influenced. In conclusion, magnesium-related particles did not restrict the immune function of macrophages, suggesting that magnesium implants and corrosion particles derived thereof are highly biocompatible and have a low inflammatory potential.Electronic supplementary materialThe online version of this article (doi:10.1007/s40204-014-0032-9) contains supplementary material, which is available to authorized users.

Alkalization is responsible for antibacterial effects of corroding magnesium

“…Prospective applications for degradable metallic implants in soft tissue are vascular stents to keep blood vessels open until newly formed vessels can overtake their function or in hard tissue, screws or nails to stabilize broken bones until the healing process is completed. Advantages of magnesium alloys that have been reported include bone regenerating, non‐inflammatory as well as antibacterial properties . Such inherent antibacterial activities of implants could antagonize the formation of antibiotic treatment‐resistant bacterial biofilm infections and would therefore be highly relevant .…”

“…Advantages of magnesium alloys that have been reported include bone regenerating, non-inflammatory as well as antibacterial properties. [4][5][6][7][8][9][10][11][12][13] Such inherent antibacterial activities of implants could antagonize the formation of antibiotic treatment-resistant bacterial biofilm infections and would therefore be highly relevant. 14,15 To simplify the analysis of the corrosion products, in this study pure magnesium was used.…”

Phosphate conversion coating reduces the degradation rate and suppresses side effects of metallic magnesium implants in an animal model

“…However, inflammatory or cytotoxic alloy metal corrosion products could accumulate with time and lead to long‐term side effects such that this approach may have serious limitations . After an initial burst of corrosion, magnesium hydroxides as well as molecules from the biological environment such as phosphorus and calcium form a protective coating that slows down the subsequent corrosion process and improves the biological properties of magnesium‐based implants . Therefore, artificial coatings generated in vitro have been investigated to control the corrosion rate in particular during the critical time period immediately after implantation .…”

“…2,17 After an initial burst of corrosion, magnesium hydroxides as well as molecules from the biological environment such as phosphorus and calcium form a protective coating that slows down the subsequent corrosion process and improves the biological properties of magnesium-based implants. [18][19][20][21][22][23] Therefore, artificial coatings generated in vitro have been investigated to control the corrosion rate in particular during the critical time period immediately after implantation. [24][25][26][27][28][29] So far there has been no robust and efficacious coating reported that fulfills the expectations with regard to the absence of toxic components, efficacy and stability in vivo.…”

In vitro study of the inflammatory cells response to biodegradable Mg-based alloy extract

“…Macrophages could regulate the degradation of biomaterials by secreting proteolytic enzymes, matrix metalloproteinases and phagocytosis [ 42 , 43 ]. Macrophages maintained the ability of clearing intracellular mycobacterium segments via phagocytosis under an environment containing magnesium particles [ 44 ]. Our results further revealed the phagocytosis of macrophage could be only affected by high concentration extract of Mg-based alloy.…”