EVALUATION OF ARTECOLL POLYMETHYLMETHACRYLATE IMPLANT FOR SOFT-TISSUEAUGMENTATION - BIOCOMPATIBILITY AND CHEMICAL CHARACTERIZATION

Artecoll polymethylmethacrylate implant (Artecoll) is a combination of polymethylmethacrylate beads suspended in 3.5% atelocollagen and has been designed for use in soft-tissue augmentation applications. The bi ocompatibility and immunogenicity of Artecoll were evaluated to assess the safety of this product for use in tile dermis. To characterize th e collagen component, chemical analysis was performed including trypsi n sensitivity, differential scanning calorimetry, and pepsin content. Particle size analysis was also per-fanned on the polymethylmethacryla te beads. The ability of this material to elicit an immunologic respon se was measured in a sensitized and nonsensitized guinea pig intraderm al model. In these studies, 24 guinea pigs were injected intradermally with either Artecoll or Zyderm, a bovine collagen product fur soft-ti ssue augmentation. Sis sites were evaluated for each material at 3, 7, and 28 days after injection. In the sensitized model, 60 guinea pigs were divided into five groups, and each group received a sensitizing d ose (in conjunction with Freund's adjuvant) of Zyderm, Artecoll, or a nonsensitizing dose of the same materials, The fifth group served as a nontreatment control. After the animals were sensitized, they were ch allenged with intradermal injections of various antigens to evaluate d elayed type hyperse nsitivity reactions. Chemical characterization ind icated polymethylmethacrylate beads of varying sizes, including many l ess than 35 microns, and a vehicle of extensively denatured and impure collagen. In vivo evaluations indicated that Artecoll elicited an imm une response in guinea pigs, including delayed type hypersensitivity a nd antibody reactions. Histological assessment demonstrated particle p hagocytosis and transepidermal elimination. Following immunization wit h Artecoll, guinea pigs were also found to he sensitized to pepsin, an impurity found in the collagen carrier. Tile biocompatibility of this material was compared with thar of bovine dermal collagen (Zyderm col lagen implant), which is widely used and accepted as biocompatible. Th e results of this evaluation indicate that Artecoll polymethylmethacry late implant has tile potential to elicit an immune response in humans . and polymethylmethacrylate beads are susceptible to phagocytosis and elimination.