Microvascular response to calcium phosphate bone substitutes: an intravital microscopy analysis

Objectives The purpose was to evaluate inflammatory and microcirculatory reactions after implantation of various calcium phosphate bone substitutes in an in vivo model. Methods Calcium phosphate-based bone substitutes were implanted in dorsal skinfold chambers of mice. Intravital fluorescence microscopy was performed to measure inflammatory and microcirculatory reactions based on functional vessel density (FVD), capillaiy leakage, and relative white blood cell velocity (rWBCV). Results An increase of FVD was observed in all groups and the capillary leakage grew with a level of significance (p<0.001). The fraction of rolling and sticking leukocytes (rWBCV) was highest at the beginning of the trial and decreased during the course. Conclusions There are differences in microvascular soft tissue reactions between various calcium phosphate bone substitutes, but inflammatory reactions were moderate, and the results revealed no reasons which explain the sporadic failure of the tested substances under clinical conditions.