Neovascularization And Macrophage Behavior Under The Influence Of Androgens In The Tissue-Implant Response.

: Macrophages and blood vessels are critical components in the biocompatibility and functionality of implantable ceramic materials used in drug delivery applications. The purpose of this study was to examine the correlation of macrophage and neovascularization by further defining their presence, relationship, and correlation in the fibrous tissue capsule of calcium phosphate (TCP) ceramic drug delivery systems. Sixteen animals in four experimental groups were implanted with one TCP bioceramic each. Group I animals were implanted with a TCP ceramic not containing a biologic (control group). Group II animals received the testosterone loaded TCP ceramic. Group III animals were implanted with the dihydrotestosterone loaded ceramic. Group IV animals received the androstenedione ceramic. At 90 days post-implantation, the animals were euthanized. Implants and fibrous tissue capsules were collected. Determination of macrophage populations and neovascularity was conducted microscopically following H&E staining and aided by ImagePro digital analysis software. Androgens have varying effects on vascularity and macrophage populations. Overall, macrophage counts were highly and significantly correlated with vascularity (p<0.05), particularly in Groups II, III, and IV. Correlations for Group I was not statistically significant. These findings suggest that presence of macrophages is be directly related to neovascularity, especially in the presence of exogenous androgens.