Vitalization of Porous Polyethylene (Medpor ® ) with Chondrocytes Promotes Early Implant Vascularization and Incorporation into the Host Tissue

Abstract

Porous polyethylene (Medpor^®) is frequently used in craniofacial reconstructive surgery. The successful incorporation of this alloplastic biomaterial depends on adequate vascularization. Here, we analyzed whether the early vascularization of porous polyethylene can be accelerated by vitalization with human chondrocytes. For this purpose, small polyethylene samples were coated with platelet-rich plasma (PRP) or a suspension of PRP and human chondrocytes. Uncoated polyethylene samples served as controls. Subsequently, the samples were implanted into the dorsal skinfold chamber of CD-1 nude mice to repetitively analyze their vascularization and biocompatibility by means of intravital fluorescence microscopy. PRP-chondrocyte-coated polyethylene exhibited an accelerated and improved vascularization when compared with the other two groups. This was indicated by a significantly higher functional capillary density of the microvascular network developing around the implants. Moreover, a leukocyte-endothelial cell interaction was found in a physiological range at the implantation site of all three groups, demonstrating that the vitalization with PRP and chondrocytes did not affect the good biocompatibility of the alloplastic material. Additional histological, immunohistochemical, and in situ hybridization analyses revealed that the chondrocytes formed a bioprotective tissue layer, which prevented the accumulation of macrophages and foreign body giant cells on the polyethylene surface. These findings clearly indicate that vitalization of polyethylene with chondrocytes promotes early implant vascularization and incorporation into the host tissue and, thus, may be a promising approach that prevents postoperative complications such as implant extrusion, migration, and infection.