Quantification of angiogenesis. Vessel density in the three implants was analyzed showing the significant effect of liposomal PlGF-1 release from MLCs on angiogenesis. At day 2, no vessel development is observed, while at day 5, the highest vessel density is seen in (3). At day 10, vessel density stabilizes in (3) due to loss of immature vessels, while it finally starts to increase in (1). A moderate increase in vessel density is seen in (2) from day 5 to day 10. Different Greek letters indicate statistically significant differences.