Figure 6.

Influence of serum-borne heparin and sFlt-1 on VEGF release. (A) Time for 50% release, t₅₀, calculated for 1.6% VBP and VBP_WT microspheres releasing bound VEGF into medium containing albumin-only solution with or without supplemented heparin. Briefly, microspheres were incubated in an albumin-only solution containing VEGF with or without heparin. Subsequent release was measured in albumin-only solution with or without heparin. t₅₀ values were calculated as described in the Materials and Methods section. Data is shown for VBP (black bars) and VBP_WT microspheres (white bars) for both treatment groups described on the x-axis. Scramble and Blank microspheres were omitted because data could not be modeled using logarithmic regression analysis. Statistical significance was only observed between VBP and VBP_WT in albumin-only solution at p-value <0.05 and denoted by asterisk (*). No significant differences were observed between t₅₀ values for VEGF release into albumin-only medium with or without heparin. (B) Normalized t₅₀ values for VEGF release from VBP and VBP_WT microspheres in albumin-only solution with 1 or 10 ng mL^–1 sFlt-1. Values were normalized to t₅₀ in 1 ng mL^–1 sFlt-1 for comparison. Statistical significance was observed for VEGF release from VBP microspheres (p-value <0.05), denoted by an asterisk (*).