To assess the prevention of recanalization at embolized sites in
cerebral arteriovenous malformations, the authors devised a novel embolic material,
hydrogel microspheres prepared from
poly(ethylene glycol) diacrylate impregnated with
basic fibroblast growth factor. In this article, preparation of the
microspheres, and preliminary study of in vitro and in vivo performance are discussed.
Poly(ethylene glycol) diacrylate, prepared from end capping of poly(
ethylene glycol) (molecular weights, 1,000, 2,000, and 4,000) with
acryloyl chloride and
benzophenone derived poly(
ethylene glycol), prepared from poly(
ethylene glycol) (molecular weight, 2,000) with benzoyl
benzoic acid chloride as a photoinitiator, were dissolved in a
buffer solution with or without
basic fibroblast growth factor. The mixed
solution was dropped stepwise into
liquid paraffin with stirring. Ultraviolet light irradiation resulted in the formation of relatively rigid
hydrogel microspheres (diameter, 100-400 microm). The in vitro study showed that the higher the molecular weight of
poly(ethylene glycol) diacrylate used, the faster the release rate of immobilized
protein. Canine kidneys were embolized with these
microspheres via the femoral artery using a microcatheter. Histologic examination showed that
microspheres occluded arterioles. The degree of accumulation of fibroblasts and extracellular matrix were larger for
basic fibroblast growth factor impregnated
microspheres than for nonimpregnated ones.
Basic fibroblast growth factor released from
microspheres may help regenerate tissues at
arteriovenous malformation sites, and recanalization is expected to be prevented.