Bioabsorbable, elastomer-coated magnesium alloy coils for treating saccular cerebrovascular aneurysms

Seungil Kim; Kamil W Nowicki; Sangho Ye; Kyeongwoo Jang; Moataz Elsisy; Mohamed Ibrahim; Youngjae Chun; Bradley A Gross; Robert M Friedlander; William R Wagner

doi:10.1016/j.biomaterials.2022.121857

Bioabsorbable, elastomer-coated magnesium alloy coils for treating saccular cerebrovascular aneurysms

Biomaterials. 2022 Nov:290:121857. doi: 10.1016/j.biomaterials.2022.121857. Epub 2022 Oct 17.

Authors

Affiliations

¹ McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
² Department of Neurosurgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
³ Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
⁴ Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
⁵ McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
⁶ McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: wagnerwr@upmc.edu.

PMID: 36326510
DOI: 10.1016/j.biomaterials.2022.121857

Abstract

Cerebral aneurysm embolization is a therapeutic approach to prevent rupture and resultant clinical sequelae. Current, non-biodegradable metallic coils (platinum or tungsten) are the first-line choice to secure cerebral aneurysms. However, clinical studies report that up to 17% of aneurysms recur within 1 year after coiling, leading to retreatment and additional surgery. It would be ideal for the aneurysm coiling material to induce acute thrombotic occlusion, contribute to a tissue development process to fortify the degenerated vessel wall, and ultimately resorb to avoid leaving a permanent foreign body. With these properties in mind, a new fatty amide-based polyurethane urea (PHEUU) elastomer was synthesized and coated on biodegradable metallic (Mg alloy) coils to prepare a bioabsorbable cerebral saccular aneurysm embolization device. The chemical structure of PHEUU was confirmed using two-dimensional nuclear magnetic resonance spectroscopy. PHEUU showed comparable physical properties to elastomeric biodegradable polyurethanes lacking fatty amide immobilization, modest enzymatic degradation profiles in the first 8 wks, inherent antioxidant activity (>70% at 48 h), no cytotoxicity, and better protection for the underlying Mg alloy than poly(lactic-co-glycolic acid) (PLGA) against surface corrosion and cracking. Rat aortic smooth muscle cell attachment and platelet deposition were higher with the PHEUUs compared to bare or PLGA coated Mg alloy in vitro. PHEUU-coated Mg alloy coils showed the potential to design a fully bioabsorbable embolization coil amenable to clinical placement conditions based on computational mechanics modeling and blood-contacting test using an in vitro aneurysm model. In vivo studies using a mouse aneurysm model elicited comparable inflammatory cytokine expression to a commercially available platinum coil.

Keywords: Bioabsorbable magnesium alloy embolization coil; Saccular aneurysm embolization; Unsaturated fatty amide-based polyurethane urea.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Absorbable Implants
Alloys
Amides
Animals
Cerebral Angiography
Elastomers
Intracranial Aneurysm* / therapy
Magnesium*
Platinum
Rats
Treatment Outcome

Substances

Magnesium
Platinum
Alloys
Elastomers
Amides