Histopathological Findings in Experimental Aneurysms Embolized with Conventional and Thrombogenic/Antithrombolytic Guglielmi Coils

Abstract

We studied the short- and long-term histological responses induced by conventional and modified electronically detachable coils (GDCs) in experimental aneurysms. Eighteen carotid bifurcation aneurysms were produced microsurgically in rabbits. Six animals each were treated either with conventional or with GDCs coated with a mixture of tissue-thromboplastin to enhance intra-aneurysmal thrombus formation and of plasminogen activator inhibitor type-1 (PAI-1) in inhibit intra-aneurysmal clot fibrinolysis. Six served as untreated controls. Follow-up angiograms were obtained immediately and at 3, 6, 9, 12, 17, and 24 weeks after embolization prior to sacrifice of the animals. All aneurysms were studied macroscopically and histopathologically with the coils in situ. Five of six control aneurysms remained patent. Endovascular occlusion rates between > 90% and 100% were achieved in nine of twelve coiled aneurysms. Follow-up angiography demonstrated recanalization and coil compaction in 5 of them. Gross and microscopic histopathological examination revealed a membrane covering the orifice, intra-aneurysmal scar formation, and development of a neo-intima in both treatment groups at 17 and 24 weeks postembolization. The granulation tissue response appeared to be equally distributed in aneurysms treated with either uncoated or coated coils. Further quantitative morphometric studies are needed to prove if a thrombogenic/antithrombolytic coil-coating might be of value in providing a more enduring anatomic result after GDC-treatment of human brain aneurysms.

In Vivo Experimental Intracranial Aneurysm Models: A Systematic Review

“…Inspired by the pioneering work of German and Black (1954), 12 surgical constructions in rabbits, swine, and dogs varied in complexity, from lateral wall types by end-to-side suturing of a segment of vein to carotid arteries, [13][14][15] to bifurcation aneurysms, anastomosing the right and left carotid arteries at the site of venous pouch implantation. 8,[16][17][18][19] (For a review, see Massoud et al 1994. 20 ) The elastase-induced aneurysm model, most frequently used in rabbits, 21,22 has been modified in various ways.…”

Controlled release of osteopontin and interleukin-10 from modified endovascular coil promote cerebral aneurysm healing

“…Matrix coils are platinum coils coated with bioabsorbable polymers that are designed to improve tissue growth and further aneurysm occlusion [21]. Since fibroblast invasion and thrombus formation has play a fundamental role in aneurysm healing, coils coated with fibroblast and thrombogenic/antithrombolytic molecules have also been tested in animal models including rabbits and rats showing promising improvement in aneurysm healing [22,23]. More creative studies have used fibroblast as vectors to deliver proteins to treat aneurysm by generating special platinum coils coated with virus-transfected fibroblast [24].…”

Improved Microsurgical Creation of Venous Pouch Arterial Bifurcation Aneurysms in Rabbits

“…2 Thus, experimental animal studies are crucial to test new and better endovascular devices, to improve long-term aneurysm occlusion. [3][4][5] The choice of the model is essential for the comparability of experimental findings with human conditions. 6 In a comparison of the currently used animal models in rats, rabbits, canines, and swine, [7][8][9] the rabbit model showed advantageous comparability with the human coagulation system and the best cost-effectiveness.…”