Entwicklung und Beurteilung Polydioxanon-basierter Mikrosphären als temporäres Embolisationsmaterial zur kathetergestützten transarteriellen Embolisation im Kaninchen Nierenmodell

Development and evaluation of polydioxanone-based microspheres as temporary embolization material for transarterial embolization in a rabbit kidney model

The objective/aim of the present animal study was to investigate the in-vivo behavior of novel temporary embolization microspheres made of polydioxanone. It is a hypothesis-generating primary study in which the basic properties (feasibility, safety, efficacy, resorbability and biocompatibility) of the newly developed material were examined in a renal embolization model in 16 clinically healthy New Zealand White.
For this purpose, newly size-calibrated (100-150 µm and 90-315 µm) and biodegradable microspheres made of polydioxanone were developed. The selective unilateral embolization of the kidney poles was performed randomized and under fluoroscopic control. The effectiveness of the embolization was confirmed by means of digital subtraction angiography (DSA) and magnetic resonance imaging (MRI).
Three animals (group 0) were euthanized immediately after embolization in order to assess the acute behavior of the particles. The remaining 13 animals were subjected to control imaging (DSA and MRT) after 1, 4, 8, 12 or 16 weeks to assess resorbability and reperfusion. This was followed by euthanasia and laboratory processing of the target organs for the histopathological examination of the resorbability and biocompatibility of the microspheres.
Renal embolization with polydioxanone microspheres was safe to perform in all rabbits. The injection through conventional catheter systems was moderately easy. The embolization resulted in an effective vascular occlusion, which was confirmed by DSA and MRI as well as in histopathology. The DSA and MRT controls after 1, 4, 8, 12, or 16 weeks showed partial to complete reperfusion as an indication of resorbability of the microspheres. The histopathological examination confirmed the resorbability through a microscopically visible and progressive particle degradation over time. The degradation of the microspheres was accompanied by a mild to moderate inflammatory / foreign body reaction with no evidence of tissue intolerance.
In conclusion the novel temporary embolization microspheres made of polydioxanone are characterized by good applicability and safety in the rabbit kidney embolization model, as well as reliable efficacy, resorbability and biocompatibility. In order to enable clinical application, biochemical modifications to the particles with the aim of accelerated degradation behavior and improved injectability are necessary.