OCR Text |
Show SCHOOL OF MEDICINE AND HEALTH SCIENCES Roy Bloebaum 116 QUANTITATIVE ANALYSIS OF PERIPROSTHETIC COLLAGEN CONTENT AROUND THE PERCUTANEOUS IMPLANT Taylor Ford (Roy Bloebaum, Sujee Jeyapalina) Department of Orthopaedics University of Utah Achievement of infection-free skin seal with percutaneous implants would allow significant advances in maintaining an internal access from external environment while retaining the homeostasis of the site. To date, none of the percutaneous devices claim to prevent infection indefinitely. Lack of understanding and directed research of implant-soft tissue interaction m a y well be the limiting factor in achieving this ultimate goal. Moreover, previous literature suggested that the periprosthetic tissue mainly m a d e of granulation tissue type and epithelium does continue to migrate along this matrix to exteriorize the implant. It is known that the collagen matrix formation (granulation tissue) and remodeling (dermis formation) are vital parts of the w o u n d healing process. Granulation tissue is mainly m a d e of collagen III and it is the matrix that is initially deposited. With the progression of w o u n d healing, it then remodels into mature dermis with the deposition of collagen I. Thus, it was hypothesized that the composition of these collagen types within the periprosthetic tissue, as a ratio of collagen I to III, could be used to measure the maturity of the granulation tissue and hence the degree of biocompatibility of the implant surfaces. The periprosthetic tissue samples with different biomimetic coatings (keratin and HA) from an ongoing animal model were collected and analyzed to prove this concept. The skin tissue samples taken at the interfaces (both at surgery and necropsy) were flash frozen, sectioned, stained with the appropriate antibodies for collagen I and III visualization, and imaged using confocal microscopy. Periprosthetic granulation tissues from these sections were identified and carefully teased out from the rest of the tissue, digested in pepsin, subjected to ELISA analysis, and the collagen hill ratios were computed.The data indicated that there were differences in the collagen contents within the granulation tissue with respect to the coating type. It appeared that there was more collagen III in the granulation tissue in the post-necropsy samples. Additionally, there was a trend found that the HA coating had weaker collagen III immunofluorescence signals in the granulation bed, perhaps indicating that the periprosthetic tissue was continuing to remodel. The data from ELISA analyses of collagen I and III was found that the ratio differed with the bio-mimetic coating types. The keratin coating showed a ratio of 1.4:1, while the H A coating showed an increase in collagen I with a ratio of 5.11:1. In contrast, the control showed a ratio of 1:111 of 0.6:1. The ELISA analyses indicated that H A coated implants had a more mature granulation bed compared to the other two coating types. It was concluded that a refined method based on this study could be used as a biocompatibility assessment tool for future biomaterial selection. |