Embolic effects of superabsorbent polymer microspheres in rabbit renal model: comparison with tris-acryl gelatin microspheres and polyvinyl alcohol.
OBJECTIVE
We have developed a spherical embolic agent, superabsorbent polymer microspheres (SAP-MS). The aim of this study was to examine the embolic effects of SAP-MS in comparison with polyvinyl alcohol (PVA) particles and tris-acryl gelatin microsphere (Embosphere Microsphere; EM) in a rabbit renal model.


METHODS
The right kidneys of nine rabbits were embolized with the given agents: PVA (180-300 microm) (n=3), EM (100-300 microm) (n=3), and SAP-MS (106-150 microm) (n=3). The embolized kidneys were evaluated by angiography and histology after one week.


RESULTS
Renal artery occlusion and prominent coagulative necrosis were confirmed regardless of agent. PVA aggregated in the proximal vessels with tiny fragments migrating into glomeruli. Both EM and SAP-MS traveled distally up to the interlobular artery level, and a single particle achieved cross-sectional vessel occlusion. SAP-MS was markedly swollen, deformed, and conformed to the vessel lumen compared with the constantly spherical EM. Mild perivascular reaction was seen with both microspheres.


CONCLUSIONS
SAP-MS resulted in targeted end-organ infarction in the rabbit renal model and showed different mechanical properties from other agents.
Khankan
Azzam A
AA
Received February 13, 2004; revision accepted April 22, 2004. Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Osuga
Keigo
K
Hori
Shinichi
S
Morii
Eiichi
E
Murakami
Takamichi
T
Nakamura
Hironobu
H
D000180:Acrylic Resins; D000792:Angiography; D000818:Animals; D003287:Contrast Media; D004621:Embolization, Therapeutic; D005780:Gelatin; D007485:Ioxaglic Acid; D007672:Kidney Cortex / Q000000981:diagnostic imaging / Q000473:pathology; D007678:Kidney Glomerulus / Q000000981:diagnostic imaging / Q000473:pathology; D008863:Microspheres; D023421:Models, Animal; D010316:Particle Size; D011108:Polymers; D011142:Polyvinyl Alcohol; D011817:Rabbits; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D013499:Surface Properties
D000180:Acrylic Resins; D003287:Contrast Media; D011108:Polymers; C496735:trisacryl gelatin microspheres; D005780:Gelatin; D011142:Polyvinyl Alcohol; D007485:Ioxaglic Acid