Cytocompatibility of magnesium alloys with adult human endothelial cells

Biodegradable materials such as magnesium alloys have raised great interest in the last few years, since long-term implants such as intravascular stents are associated with various side effects. However, ions released from these alloys can exhibit cytotoxicity, which may have a severe impact on healing after implantation. The authors investigated the cytological effects of eight different magnesium alloys containing varying amounts of aluminum, zinc, neodymium and yttrium. Magnesium alloys were incubated either directly or indirectly with the endothelial cell line EA.Hy926 or primary endothelial cells from different patients, and cell viability was measured. In addition, the concentrations of released metal ions from the alloys were determined. Dependent on the magnesium alloys used and the incubation period, direct or indirect contact with endothelial cells led to various reactions in cell viability. Only the MgAl9Zn1alloy was found to exhibit tolerable cytotoxicity on all endothelial cells tested. The in vitro study revealed that the cytocompatibility of biodegradable magnesium alloys is not predictable only by determining the ion release or by testing the alloys with immortalized cell lines. These data suggest that cytocompatibility properties of new biodegradable material should be tested using primary cells of various donors in order to guarantee safe in vivo application and avoid interindividual differences.