CONDITIONED MEDIA FROM IMPLANT REVISION MEMBRANES ENHANCE MACROPHAGE TARTRATE RESISTANT ACID PHOSPHATASE SECRETION IN VITRO

Abstract

The effect of conditioned media from implant revision membranes on tartrate resistant acid phosphatase (TRAP) secretion following PE exposure was investigated. Human Monocytes were cultured on PE/collagen coverslips, and 50 uls of culture media, conditioned media from implant revision membranes, or conditioned media from synovium was added. Cultured media were collected, and analyzed for TRAP activity. Statistical analysis showed significantly greater release of TRAP in the media with the supplement of the conditioned media from implant revision membranes, indicating that the unknown factors in the conditioned media could accelerate monocyte-macrophage TRAP secretion. Identifying and blocking of the factors would be beneficial for long-term implant performance.

The purpose of this study was to investigate the effect of conditioned media from implant revision membranes on monocyte-macrophage tartrate resistant acid phosphatase (TRAP) secretion.

Conditioned media from implant revision membranes significantly enhanced monocyte-macrophage TRAP secretion following PE exposure in vitro.

Since TRAP has been related to bone resorption, identifying and blocking factors stimulating monocyte-macrophage TRAP section would be beneficial for preventing peri-implant bone resorption.

Monocytes isolated from human blood were cultured on PE/collagen coverslips, and 50 uls of fresh culture media, conditioned media from implant revision membrane, or conditioned media from synovium was added at time zero, day two and four. Cultured media were collected at day two, four and six, and analyzed for TRAP activity. As previously reported the conditioned media from the revision membranes contained TRAP activity greater than synovial membranes. Therefore the accumulative TRAP activity after culturing macrophages with PE was corrected by subtracting TRAP activity measured in the conditioned media prior to DNA normalization. Statistical analysis showed significantly greater release of TRAP in media with addition of the conditioned media from implant revision membrane when compared with either conditioned media from synovium or fresh culture media (p< 0.01, n=3). This result indicates that certain unknown soluble factors in the conditioned media from implant revision membrane could accelerate monocyte-macrophage TRAP secretion. Since TRAP enzyme has been related to bone resorption, greater TRAP secretion could lead to peri-implant osteolysis and subsequent implant loosening. Identifying and blocking of those factors would be ultimately beneficial for implant long-term clinical performance.

Funding: Canadian Orthopaedic Research Foundation and Arthritis Society