A promising biodegradable magnesium alloy suitable for clinical vascular stent application

Abstract

We report a Mg alloy Mg-2.2Nd-0.1Zn-0.4Zr (wt.%, denoted as JDBM-2) showing great potential in clinical vascular stent application by integrating the advantages of traditional medical stainless steel and polymer. This alloy exhibits high yield strength and elongation of 276 ± 6 MPa and 34.3 ± 3.4% respectively. The JDBM-2 with a stable degradation surface results in a highly homogeneous degradation mechanism and long-term structural and mechanical durability. In vitro cytotoxicity test of the Mg extract via human vascular endothelial cells (HUVECs) indicates that the corrosion products are well tolerated by the tested cells and potentially negligible toxic effect on arterial vessel walls. This alloy also exhibits compromised foreign body response (FBR) determined by human peripheral blood derived macrophage adhesion, foreign body giant cell (FBGC) formation and inflammatory cytokine and chemokine secretion. Finally, vascular stents manufactured from the JDBM-2 were implanted into rabbits for long-term evaluation. The results confirm excellent tissue compatibility and up to 6-month structural and mechanical integrity of the stent in vivo. Thus, the JDBM-2 stent with up to 6-month structural and mechanical integrity and excellent tissue compatibility represents a major breakthrough in this field and a promising alternative to traditional medical stainless steel and polymer for the clinical application.

Building towards a standardised approach to biocorrosion studies: a review of factors influencing Mg corrosion in vitro pertinent to in vivo corrosion

“…Additionally, a similar phenomenon has also been reported for stents where a layer of endothelium coated the struts of a Mg stent implanted into the abdominal aorta of New Zealand white rabbits [134]. Tissue encapsulation appears to be an expected result of contact with blood [98,135].…”

In vitro and in vivo cytocompatibility evaluation of biodegradable magnesium-based stents: a review

“…Supporting the in vitro results, the Mg-based stents in vivo also promote the proliferation of endothelium because complete endothelialization occurs in approximately 30 days for bare Mg-based stents [32,36,39] while in 40-60 days for the drug-eluting Mgbased stents [38,39]. The biodegradable Mg-based vascular stent barely induces in-stent thrombosis [30,31,35,36,39], restenosis or occlusion [13,26,30,[33][34][35][36][37]39,45] after implantation into animal arteries. A reasonable explanation for the lack of thrombotic complications is that Mg-based alloys are electronegative and provide hypothrombogenic surfaces [36,125].…”

“…There were no or just slight signs of inflammation in most stented arteries [13,30,33,36,39,124], as a few inflammatory cells accumulated around the stent and subsided in the late-stage implantation. The minor inflammatory reaction in arteries can be reasonably attributed to the re-endothelialization and neointimal coverage on the stent struts [30].…”

“…. . clude right coronary artery (RCA), left anterior descending (LAD) and left anterior circumflex (LCX) in the consideration of mimicking the most frequent clinical cardiovascular occlusions, as well as the other sites such as abdominal aorta [30], femoral artery [13,26,31] iliac artery [32], renal artery [32] and so on.…”

“…For in vivo animal studies, the different candidate Mg-based stents were implanted into the arteries without atherosclerotic lesion at various sites. Most of the results were positive about the cellular and tissue response surrounding the stents [13,26,[29][30][31][32][33][34][35][36][37][38][39][40]. It means that the applications of Mg-based stents in the vessels are safe for the body.…”