Amino Acid coated uhmw-pe implants modify macrophage migration in the tissue-implant response - biomed 2011

Polyethylene materials used in orthopedic applications are biocompatible and non-immunogenic with host tissues. Recent studies in our laboratory have demonstrated the need for further study of these devices in vivo to further elucidate methods to modulate the tissue-implant response. The purpose of this investigation was to determine macrophage behavior after implantation of ultra high molecular weight polyethylene (UHMW-PE) rinsed with saline (control) and coated with poly-L-lysine (PLL), arginine-glycine-aspartic acid (RGD), and arginine-glycine-glutamic acid (RGE) into 16 adult male rats intraperitoneally (I/P). Implants and surrounding tissue were harvested at 90 days post-implantation. The animals were euthanized; and the UHMW-PE implants and the fibrous tissue capsules surrounding them were harvested. Microscopic examination of routinely stained sections (5 microns, Hematoxylin & Eosin) of the fibrous tissue capsules revealed macrophage counts were highest in the saline coated group (9.75±0.86 cells/high power field). Amino acid coated implants resulted in decreased mean macrophage counts per high power field for RGD (3.51±0.45), RGE (2.86±0.06), and PLL (4.2±0.55) compared to saline and the differences were statistically significant (ANOVA, p < 0.05). These findings indicate macrophage behavior at the tissue-implant interface and in surrounding fibrous tissue can be reduced using various amino acid combination coatings. In addition, these results provide evidence that the intensity of the chronic inflammatory reaction to UHMW-PE can be reduced and controlled to some extent.