<i>In vivo</i> comparison of shape memory polymer foam‐coated and bare metal coils for aneurysm occlusion in the rabbit elastase model

Herting, Scott M.; Ding, Yuqin; Boyle, Anthony J.; Dai, Daying; Nash, Landon D.; Asnafi, Solmaz; Jakaitis, Daniel R.; Johnson, Collin R.; Graul, Lance M.; Yeh, Chung Hsin; Kallmes, David F.; Kadirvel, Ramanathan; Maitland, Duncan J.

doi:10.1002/jbm.b.34337

Cited by 33 publications

(72 citation statements)

References 32 publications

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“…In doing so, we have a better sense of whether or not the host response to the device is remodeling and transitioning toward a healing response. This quantitative assessment comparing three circumferential regions throughout the dome builds upon and adds to the inflammation assessment described by Herting et al (), which focused solely on a qualitative assessment that regionally only compared inflammation at the aneurysm dome and wall across groups.…”

Section: Discussionmentioning

confidence: 98%

Micro‐CT and histopathology methods to assess host response of aneurysms treated with shape memory polymer foam‐coated coils versus bare metal coil occlusion devices

et al. 2020

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Recent studies utilizing shape memory polymer foams to coat embolizing coils have shown potential benefits over current aneurysm treatments. In the current study utilizing a rabbit-elastase aneurysm model, the performance of test article (foam-coated coil [FCC]) and control (bare platinum coils [BPCs]) devices were compared at 30, 90, and 180 days using micro-CT and histological assessments. The host response was measured by identifying the cells regionally present within the aneurysm, and assessing the degree of residual debris and connective tissue. The 3D reconstructions of aneurysms provided context for histologic findings, and aided in the overall aneurysm assessment. At all time points, >75% of the cells categorized in each aneurysm were associated with a bioactive yet biocompatible host response (vs. the remainder of cells that were associated with acute inflammation). The extracellular matrix exhibited a transition from residual fibrin at 30 days to a greater degree of connective tissue at 90 and 180 days. Although the control BPC-treated aneurysms exhibited a greater degree of connective tissue at the earliest time point examined (30 days), by 180 days, the FCC-treated aneurysms had more connective tissue and less debris overall than the control aneurysms. When considering cell types and extracellular matrix composition, the overall host response scores were significantly better in FCC-treated aneurysms at the later time point. Based on the results of these metrics, the FCC device may lead to an advanced tissue remodeling response over BPC occlusion devices. K E Y W O R D Shealing metric, histopathology, micro-CT, occlusion devices, shape memory polymer

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Section: Discussionmentioning

confidence: 98%

Micro‐CT and histopathology methods to assess host response of aneurysms treated with shape memory polymer foam‐coated coils versus bare metal coil occlusion devices

et al. 2020

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“…33 Coil treatment itself increases the inflammatory response in the rabbit model. 34 Our findings indicate that M1 and M2 macrophage levels are due to tissue responses to coil implants. This study has several limitations.…”

Section: Discussionmentioning

confidence: 59%

“…19 Some of the rabbits used in this study were originally part of another investigation, in which bare platinum coils were used to treat the aneurysms. The original investigation was entirely unrelated to this project, 20 and did not interfere with the goals of this study.…”

Section: Aneurysm Creation and Tissue Harvestmentioning

confidence: 99%

The Distribution and Role of M1 and M2 Macrophages in Aneurysm Healing after Platinum Coil Embolization

Khashim

Daying

Hong

et al. 2020

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Impairment of macrophage polarization from a proinflammatory macrophage type 1 (M1) population to an anti-inflammatory macrophage type 2 (M2) population is a hallmark of poor wound healing. In this study, we aimed to evaluate the distribution of M1 and M2 macrophages and to analyze their association with healing in aneurysms embolized by endovascular coiling. MATERIALS AND METHODS: Elastase-induced aneurysms were created in female rabbits and subsequently embolized with platinum coils. Aneurysm occlusions were evaluated with angiographic imaging at 1 (n ¼ 6), 3 (n ¼ 5), or 6 (n ¼ 6) months. Aneurysm tissues were harvested for histologic analysis, quantification of M1 and M2 macrophages by immunofluorescence, and collagen deposition determined by Masson trichrome staining. Histologic grading of aneurysm healing was also performed. Untreated aneurysms were used as controls (n ¼ 6). RESULTS: The M1 macrophage population was highest at 1 month posttreatment, progressively decreasing at 3 and 6 months. The M2 macrophage population progressively increased at 3 and 6 months posttreatment. The highest collagen deposition was at 6 months posttreatment. We found a moderate-to-weak direct correlation between the percentage of M2 macrophages and collagen deposition, as well as total histologic scores overall, and a strongly positive direct correlation between the percentage of M2 macrophages and total histologic scores at 6 months posttreatment.

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“…In a subsequent aneurysm occlusion in vivo test in a rabbit elastase model, Herting et al. [ 166 ] found that a coil coated with a porous SMP foam could promote neointima formation in the aneurysm neck, which in turn led to a full recovery. Metzger et al.…”

Section: Recent Advances In Applications Of Smps and Smpcsmentioning

confidence: 99%

A Review of Shape Memory Polymers and Composites: Mechanisms, Materials, and Applications

et al. 2020

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Over the past decades, interest in shape memory polymers (SMPs) has persisted, and immense efforts have been dedicated to developing SMPs and their multifunctional composites. As a class of stimuli‐responsive polymers, SMPs can return to their initial shape from a programmed temporary shape under external stimuli, such as light, heat, magnetism, and electricity. The introduction of functional materials and nanostructures results in shape memory polymer composites (SMPCs) with large recoverable deformation, enhanced mechanical properties, and controllable remote actuation. Because of these unique features, SMPCs have a broad application prospect in many fields covering aerospace engineering, biomedical devices, flexible electronics, soft robotics, shape memory arrays, and 4D printing. Herein, a comprehensive analysis of the shape recovery mechanisms, multifunctionality, applications, and recent advances in SMPs and SMPCs is presented. Specifically, the combination of functional, reversible, multiple, and controllable shape recovery processes is discussed. Further, established products from such materials are highlighted. Finally, potential directions for the future advancement of SMPs are proposed.

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In vivo comparison of shape memory polymer foam‐coated and bare metal coils for aneurysm occlusion in the rabbit elastase model

Cited by 33 publications

References 32 publications

Micro‐CT and histopathology methods to assess host response of aneurysms treated with shape memory polymer foam‐coated coils versus bare metal coil occlusion devices

Micro‐CT and histopathology methods to assess host response of aneurysms treated with shape memory polymer foam‐coated coils versus bare metal coil occlusion devices

The Distribution and Role of M1 and M2 Macrophages in Aneurysm Healing after Platinum Coil Embolization

A Review of Shape Memory Polymers and Composites: Mechanisms, Materials, and Applications

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