请将下方内容用更为地道、更为科学的英文表达出来：The formation of vascular networks by HUVECs as assessed by the area of vessel positivity was progressively augmented with the increasing proportion of fibrin in the hydrogel

The vascular network formation by human umbilical vein endothelial cells (HUVECs), as determined by the vessel positivity area, was found to be progressively enhanced with the increasing proportion of fibrin in the hydrogel.