In vivo response of AZ31 alloy as biliary stents: a 6 months evaluation in rabbits

Abstract

Mg-based metallic materials have been making continuing progress as vascular stents. However, the research of Mg-based materials as non-vascular stents is still at its primary stage. AZ31 stents hereby were implanted into the common bile duct of rabbits for 6 months. The results revealed an existence of 93.82 ± 1.36% and 30.89 ± 2.46% of the original volume after 1 and 3 month, respectively. Whole blood tests indicated an inflammation decreasing to normal level after 3 month implantation. A benign host response was observed via H&E staining. Nonuniform corrosion at the two ends of the stents was observed and considered the results of flow or local inflammation. Moreover, the application of Mg-based materials for different stenting treatment were reviewed and compared. Esophagus was hypothesized most destructive, whilst blood vessel and bile duct considered similar and less destructive. Trachea and nasal cavity were thought to be mildest.

The current trends of Mg alloys in biomedical applications—A review

“…Similarly, both the serum magnesium and urea nitrogen had an increase during implantation but came back to normal after 6 months. The study concluded the biosafety of Mg alloy AZ31 stent but pointed out the need to improve the corrosion resistance . In another study, Mg and AZ31 craniofacial bone screws were compared by implanting them in the rabbits.…”

“…There are few studies that discuss the in vivo response of Mg–Al alloys, particularly AZ31 . Liu et al investigated the corrosion and biosafety of AZ31 biliary stents in rabbits.…”

“…There are few studies that discuss the in vivo response of Mg–Al alloys, particularly AZ31 . Liu et al investigated the corrosion and biosafety of AZ31 biliary stents in rabbits. After 1, 3, and 6 months of implantations, the computed tomography (CT) scans were conducted to observe the corrosion analysis and healing process.…”

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

“…It was also noted in this study that human urine is much more variable in ionic composition between patients than blood or blood plasma [99]. Another application that could be considered is that of a Mg biliary stent, which has recently been investigated in vivo [100]. If future in vitro tests prove necessary for this application, a simulated bile solution would seem appropriate for in vitro biocorrosion testing.…”

A poly(L‐lactic acid) monofilament with high mechanical properties for application in biodegradable biliary stents

“…Initial animal experiments have proven that BBS are not only feasible, but also have unique advantages for example, no need for subsequent removal. [10][11][12] Nowadays, a listed product (ELLA-CS, Hradec Kralove, Czech Republic) made from polydioxanone (PDO) has been tested in small-scale clinical trials, showing promising results in treating some simple biliary structures. 13,14 However, PDO has poor mechanical properties, especially much lower Young's modulus than that of other stent materials, 15,16 which can only equip stent with limited radial force and may restrict the widespread application of BBS in treating more complex biliary strictures.…”