HGF is secreted by adipose-derived microvessel fragments in 3D constructs and mediates angiogenic sprouting. (a) In vitro analysis of HGF secretion from pre-vascularized engineered constructs. Pre-vascularized engineered constructs were maintained in 20% FBS-DMEM. Media was collected at the indicated time-points and HGF secretion was measured by ELISA (mean ± SEM; one-way ANOVA, Bonferroni correction, p ≤ 0.0001 vs. day 0). (b) Blockage of HGF/c-MET significantly reduces sprouting angiogenesis. Pre-vascularized constructs were maintained in 20% FBS-DMEM containing either anti-HGF antibody (a-HGF), c-MET inhibitor (SU11274), IgG control, or DMSO (vehicle) for 7 days (mean ± SEM; n = 3 one-way ANOVA, Bonferroni correction, anti-HGF p ≤ 0.05, SU11274, p ≤ 0.0001).