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Menze R, Hesse B, Kusmierczuk M, Chen D, Weitkamp T, Bettink S, Scheller B. Synchrotron microtomography reveals insights into the degradation kinetics of bio-degradable coronary magnesium scaffolds. Bioact Mater 2024; 32:1-11. [PMID: 37771679 PMCID: PMC10522944 DOI: 10.1016/j.bioactmat.2023.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/18/2023] [Accepted: 09/12/2023] [Indexed: 09/30/2023] Open
Abstract
Bioresorbable magnesium scaffolds are a promising future treatment option for coronary artery stenosis, especially for young adults. Due to the degradation of these scaffolds (<1 year), long-term device-related clinical events could be reduced compared to treatments with conventional drug eluting stents. First clinical trials indicate a return of vasomotion after one year, which may be associated with improved long-term clinical outcomes. However, even after decades of development, the degradation process, ideal degradation time and biological response in vivo are still not fully understood. The present study investigates the in vivo degradation of magnesium scaffolds in the coronary arteries of pigs influenced by different strut thicknesses and the presence of antiproliferative drugs. Due to high 3D image contrast of synchrotron-based micro-CT with phase contrast (SR-μCT), a qualitative and quantitative evaluation of the degradation morphology of magnesium scaffolds was obtained. For the segmentation of the μCT images a convolutional network architecture (U-net) was exploited, demonstrating the huge potential of merging high resolution SR-μCT with deep learning (DL) supported data analysis. In total, 30 scaffolds, made of the rare earth alloy Resoloy®, with different strut designs were implanted into the coronary arteries of 10 domestic pigs for 28 days using drug-coated or uncoated angioplasty balloons for post-dilatation. The degradation morphology was analyzed using scanning electron microscopy, energy dispersive x-ray spectroscopy and SR-μCT. The data from these methods were then related to data from angiography, optical coherence tomography and histology. A thinner strut size (95 vs. 130 μm) and the presence of paclitaxel indicated a slower degradation rate at 28 d in vivo, which positively influences the late lumen loss (0.5 and 0.6 mm vs. 1.0 and 1.1 mm) and recoil values (0 and 1.7% vs. 6.1 and 22%).
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Affiliation(s)
- Roman Menze
- MeKo Manufacturing e.K., Im Kirchenfelde 12-14, 31157, Sarstedt, Germany
| | - Bernhard Hesse
- Xploraytion GmbH, Bismarckstr. 10-12, 10625, Berlin, Germany
| | | | - Duote Chen
- Xploraytion GmbH, Bismarckstr. 10-12, 10625, Berlin, Germany
| | - Timm Weitkamp
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190, Saint-Aubin, France
| | | | - Bruno Scheller
- Universität des Saarlandes, Campus Homburg, 66421, Homburg, Germany
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Schilling T, Cebotari S, Kaufeld T, Tudorache I, Brandes G, Hartung D, Wacker F, Bauer M, Haverich A, Hassel T. Stabilizing A Vascularized Autologous Matrix with Flexible Magnesium Scaffolds to Reconstruct Dysfunctional Left Ventricular Myocardium in a Large-Animal Feasibility Study. J Funct Biomater 2023; 14:jfb14020073. [PMID: 36826872 PMCID: PMC9963522 DOI: 10.3390/jfb14020073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/15/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
The surgical reconstruction of dysfunctional myocardium is necessary for patients with severe heart failure. Autologous biomaterials, such as vascularized patch materials, have a regenerative potential due to in vivo remodeling. However, additional temporary mechanical stabilization of the biomaterials is required to prevent aneurysms or rupture. Degradable magnesium scaffolds could prevent these life-threatening risks. A left ventricular transmural defect was reconstructed in minipigs with a piece of the autologous stomach. Geometrically adaptable and degradable scaffolds made of magnesium alloy LA63 were affixed on the epicardium to stabilize the stomach tissue. The degradation of the magnesium structures, their biocompatibility, physiological remodeling of the stomach, and the heart's function were examined six months after the procedure via MRI (Magnetic Resonance Imaging), angiography, µ-CT, and light microscopy. All animals survived the surgery. Stable physiological integration of the stomach patch could be detected. No ruptures of the grafts occurred. The magnesium scaffolds showed good biocompatibility. Regenerative surgical approaches for treating severe heart failure are a promising therapeutic alternative to the currently available, far from optimal options. The temporary mechanical stabilization of viable, vascularized grafts facilitates their applicability in clinical scenarios.
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Affiliation(s)
- Tobias Schilling
- Department of Cardiothoracic, Transplantation, and Vascular Surgery, Medical School Hannover, 30625 Hannover, Germany
- Correspondence:
| | - Serghei Cebotari
- Institut National de Chirurgie Cardiaque et de Cardiologie Interventionelle, 1210 Luxembourg, Luxembourg
| | - Tim Kaufeld
- Department of Cardiothoracic, Transplantation, and Vascular Surgery, Medical School Hannover, 30625 Hannover, Germany
| | - Igor Tudorache
- Department of Cardiac Surgery, Universitätsspital Zürich, 8091 Zürich, Switzerland
| | - Gudrun Brandes
- Institute of Neuroanatomy and Cell Biology in the Center of Anatomy, Medical School Hannover, 30625 Hannover, Germany
| | - Dagmar Hartung
- Institute for Radiology, Hannover Medical School, 30625 Hannover, Germany
| | - Frank Wacker
- Institute for Radiology, Hannover Medical School, 30625 Hannover, Germany
| | | | - Axel Haverich
- Department of Cardiothoracic, Transplantation, and Vascular Surgery, Medical School Hannover, 30625 Hannover, Germany
| | - Thomas Hassel
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen, Germany
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Durisin M, Reifenrath J, Weber CM, Eifler R, Maier HJ, Lenarz T, Seitz JM. Biodegradable nasal stents (MgF 2 -coated Mg-2 wt %Nd alloy)-A long-term in vivo study. J Biomed Mater Res B Appl Biomater 2015; 105:350-365. [PMID: 26511430 DOI: 10.1002/jbm.b.33559] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 08/28/2015] [Accepted: 10/11/2015] [Indexed: 12/21/2022]
Abstract
Despite innovative surgical techniques and use of current frontal sinus stents from different materials, the problem of treatment failure with consecutive reoperation remains present. The aim of our study is to investigate biocompatibility, degradation kinetics, and functionality of a newly developed fluoride-coated magnesium-based nasal stent. A minipig anatomy of frontal sinus adapted design and an external surgical approach were developed and established. The functionality of the stents was evaluated endoscopically. The stent-tissue blocks were analysed after 90 and 180 days using microcomputed tomography (µ-CT), histology, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Functional evaluation revealed an unobstructed stent lumen in all cases. Histological analysis showed moderate mucosal hyperplasia with a mild, nonspecific inflammatory response, and nonosteoconductive effect. Rejection reactions or necrosis did not occur. The volumetric analysis of the stents showed 51% volume loss after 180 days. The EDS analysis did not detect any neodymium (Nd) in the mucosa or bone. The Mg-2 wt % Nd stents are a promising option when treating the narrow passages following paranasal sinus surgery. In particular, its good biocompatibility and good functionality facilitate the re-epithelization of these constricted passages. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 350-365, 2017.
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Affiliation(s)
- Martin Durisin
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, 30625, Germany
| | - Janin Reifenrath
- Department of Orthopedic Surgery, CrossBIT-Center of Biocompatibility and Implant-Immunology, Hannover Medical School, Hannover, 30625, Germany
| | - Constantin M Weber
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, 30625, Germany
| | - Rainer Eifler
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, Hannover, 30823, Germany
| | - Hans J Maier
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, Hannover, 30823, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, 30625, Germany
| | - Jan-Marten Seitz
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, Hannover, 30823, Germany.,Department of Materials Science and Engineering, Michigan Technological University, Houghton, Michigan, 49931.,Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan, 49931
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Durisin M, Seitz JM, Reifenrath J, Weber CM, Eifler R, Maier HJ, Lenarz T, Klose C. A novel biodegradable frontal sinus stent (MgNd2): a long-term animal study. Eur Arch Otorhinolaryngol 2015; 273:1455-67. [PMID: 26341887 DOI: 10.1007/s00405-015-3774-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/28/2015] [Indexed: 12/27/2022]
Abstract
The frontal sinus recess consists of anatomically narrow passages that are prone to stenosis in endonasal frontal sinus surgery for chronic sinus disease. Over the past 100 years, diverse frontal sinus stents have been developed and evaluated in clinical and animal studies. However, superinfection, formation of granulations tissue, stent dislocation and late stenosis of the duct have remained challenges and subject of debate in the literature. Currently developed biodegradable materials, including rare earth-containing magnesium alloys are promising candidates for application as temporary implant materials. The Mg 2 % wt Nd alloy (MgNd2) was used to design a nasal stent that fit the porcine anatomy. In the current study, we evaluate biocompatibility, biodegradation and functionality of a frontal sinus stent in 16 minipigs over 6 months. Intraoperative endoscopy revealed free stent lumen in all cases. Blood examination and clinical examinations indicated no systematic or local inflammation signs. The histopathology and elements analysis showed a very good biocompatibility. The μ-computed tomography-based volumetric analysis showed substantial stent degradation within 6 months. Our MgNd2 based stent appears to be a promising, solid basis for the development of a frontal sinus stent for clinical use.
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Affiliation(s)
- M Durisin
- Department of Otorhinolaryngology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.
| | - J M Seitz
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823, Hannover, Germany.,Department of Materials Science and Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, 49931, USA
| | - J Reifenrath
- Department of Orthopedic Surgery, CrossBIT, Center of Biocompatibility and Implant-Immunology, Hannover Medical School, Feodor-Lynen-Straßee 31, 30625, Hannover, Germany
| | - C M Weber
- Department of Otorhinolaryngology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - R Eifler
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823, Hannover, Germany
| | - H J Maier
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823, Hannover, Germany
| | - T Lenarz
- Department of Otorhinolaryngology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany
| | - C Klose
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823, Hannover, Germany
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Weber CM, Eifler R, Seitz JM, Maier HJ, Reifenrath J, Lenarz T, Durisin M. Biocompatibility of MgF2-coated MgNd2 specimens in contact with mucosa of the nasal sinus - a long term study. Acta Biomater 2015; 18:249-61. [PMID: 25769231 DOI: 10.1016/j.actbio.2015.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 01/26/2015] [Accepted: 03/04/2015] [Indexed: 12/28/2022]
Abstract
Up to now, different surgical techniques and stent systems have already been developed and tested for the continuous and adequate ventilation of the frontal sinuses. However, the results achieved still remain poor. Magnesium-based implants have been successfully used in numerous clinical applications. Offering excellent biocompatibility and biodegradability it may be the ideal material for the development of novel implants of the nasal sinus. Here, we present for the first time results on the behaviour of magnesium alloy in a unique environment, i.e. in contact to the nasal mucosa, air and nasal secretion. In a prospective longitudinal study, magnesium fluoride-coated MgNd2 specimens were implanted in the frontal sinuses of 12 minipigs for the investigation of biocompatibility and of the interface between the implant and the mucosa. Endoscopic examinations, histopathological evaluation and EDX measurements were performed regularly up to 180days. Endoscopic evaluation showed focal mucosal reaction, however, without affecting the patency of the sinus. In addition, no signs of bacterial infections were observed. The EDX analyses showed a marginal but steady increase in the Mg concentration in the mucosa over 180days. Histological analysis revealed a locally confined moderate mucosal hyperplasia and unspecific inflammatory reaction. Furthermore, we did not find any osteoinductive effects of the magnesium alloy. The results indicate the excellent biocompatibility of the MgNd2 alloy in contact with nasal mucosa and provide a novel material compound and solid proof-of-principle for the development of magnesium-based nasal stents.
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