In vivo degradation and endothelialization of an iron bioresorbable scaffold

Abstract

Detection of in vivo biodegradation is critical for development of next-generation medical devices such as bioresorbable stents or scaffolds (BRSs). In particular, it is urgent to establish a nondestructive approach to examine in vivo degradation of a new-generation coronary stent for interventional treatment based on mammal experiments; otherwise it is not available to semi-quantitatively monitor biodegradation in any clinical trial. Herein, we put forward a semi-quantitative approach to measure degradation of a sirolimus-eluting iron bioresorbable scaffold (IBS) based on optical coherence tomography (OCT) images; this approach was confirmed to be consistent with the present weight-loss measurements, which is, however, a destructive approach. The IBS was fabricated by a metal-polymer composite technique with a polylactide coating on an iron stent. The efficacy as a coronary stent of this new bioresorbable scaffold was compared with that of a permanent metal stent with the name of trade mark Xience, which has been widely used in clinic. The endothelial coverage on IBS was found to be greater than on Xience after implantation in a rabbit model; and our well-designed ultrathin stent exhibited less individual variation. We further examined degradation of the IBSs in both minipig coronary artery and rabbit abdominal aorta models. The present result indicated much faster iron degradation of IBS in the rabbit model than in the porcine model. The semi-quantitative approach to detect biodegradation of IBS and the finding of the species difference might be stimulating for fundamental investigation of biodegradable implants and clinical translation of the next-generation coronary stents.

Long-term safety and absorption assessment of a novel bioresorbable nitrided iron scaffold in porcine coronary artery

“…In addition, although complete bioresorption time appears to occur by 5–7 years post-implantation in a healthy porcine coronary artery, there is still room for further improvement of the nitrided iron scaffold. For example, to further shorten complete bioresorption time might be achieved via nitriding technology and be combined with biodegradable polymer to prepare metal-polymer composite scaffolds [ 12 , [28] , [29] , [30] , [31] , [32] ]. Newer iron-based bioresorbable scaffolds may hold promise among BRS.…”

Accelerated biodegradation of iron-based implants via tantalum-implanted surface nanostructures

“…Fe is the most abundant metal in the human body and participates in a wide variety of metabolic processes, such as oxygen transport, energy metabolism, enzyme function, and DNA synthesis [ 11 , 13 , 14 ]. In particular, it is known for its vital role in bone homeostasis, and a deficiency of Fe causes bone disorders and impairs bone mineralization [ 15 ].…”

Advances in coatings on magnesium alloys for cardiovascular stents – A review

“…Although animal experiments have shown that there is no intravascular thrombosis or severe inflammation during the implantation of Fe-based stents (e.g. nitrided Fe-based stents) [ 21 ], they lack the support of clinical trial data. Moreover, the degradation period of Fe-based stents is too long [ 22 ], and they are extremely susceptible to the influence of magnetic fields, which makes it impossible for patients implanted with Fe-based stents to undergo MRI [ 23 ].…”