A: AlamarBlue reduction assay was used to measure viability and growth of endothelial cells (ECs), seeded onto the luminal space of the bioprinted e-HT constructs under flow. B-Left: Bioprinted e-HT construct integrated in a custom-printed bioreactor housing. B-Right: CAD model of the e-HT structure. Zones 1 and 2 highlight the areas used for immunohistochemical (IHC) analysis. C: IHC imaging of zones 1 (top) and 2 (bottom) within the bioprinted cellular e-HT constructs, performed after 14 days of in vitro dynamic culture. From left to right, columns show immunostaining results for DAPI, CD31, connexin43, and merged, respectively. D: AlamarBlue assay demonstrating EC viability and growth on the luminal space of bioprinted e-HT constructs under dynamic flow. B-Left: Bioprinted f-LV construct in the bioreactor housing. B-Right: CAD model of the f-LV structure. Zones 1 and 2 highlight the areas used for the IHC analysis. C: IHC imaging of zones 1 (top) and 2 (bottom) in the bioprinted cellular f-LV constructs after 14 days of dynamic culture. From left to right, columns show immunostaining results for DAPI, CD31, connexin43, and merged, respectively. Note: * p < 0.05; ** p < 0.01; *** p < 0.001; and **** p < 0.0001. p value demonstrates statistically significant difference compared to value in the same group at day 1. Results are based on n = 4 constructs for the AlamarBlue assay and n = 3 per group for IHC.