Formation and characterization of a 3D
vascular channel network
composed of HMVECs and SCs. (A) Comparison of vascular networks stained
by CD31 (red) after 10 DIV, composed of HMVECs only (left), HMVECs
plus HDFs at 5:1 ratio (middle), and HMVECs plus SCs at 5:1 ratio
(right). Scale bar represents 100 μm and applies to all images.
(B) Quantification of vessel area (top left), vessel length (top right),
vessel density (bottom left), and branching density (bottom right)
formed in co-cultures of HMVECs with either SCs (black bars) or HDFs
(gray bars). The bars represent the mean ± standard deviation
(SD) of two experiments using ≥4 replicates per condition.
For the image analysis, we took at least five images per sample. Statistics
were performed using an unpaired t-test, where ****p < 0.0001, *p < 0.05, and ns denotes p > 0.05. (C, D) Micrographs depict an intimate association
between vessels (CD31; red, top row) and SCs (S100; green, middle
left) that also express α smooth muscle actin (αSMA; green,
middle right). The bottom row shows the merged images. Scale bars
represent 50 μm and apply to panels in the same column. (E)
Vascular vessels resulting from the co-culture of HMVECs and SCs stained
with the traditional markers (white in the respective panels): VE-cadherin
(top left), laminin (top right), vWF (bottom left), and col IV (bottom
right). CD31 is shown in red and DAPI in blue. Scale bars represent
50 μm. (F) Comparison of a cytokine array present in SC- (left
column) versus HDF-conditioned medium (right column). The secreted
amount of each cytokine was normalized to a normal, control medium.
The value of the ratio between conditioned and normal medium for each
cytokine was translated to a color code, denoted 0–0.99 (black),
1.00–1.99 (light green), 2.00–2.99 (dark green), 3.00–3.99
(yellow), 4.00–4.99 (red), and 5.00–10.00 (dark red).
Cytokines were organized into categories representing their most prominent
function, such as pro-angiogenic, neuromodulatory, immunomodulatory,
or wound healing. (G) Reconstruction of a vascular network stained
by CD31 (red) showing the formation of well-defined, 3D interconnected
vessels with lumens (inset, average diameter of 4.6 μm). Scale
bar in the network overview represents 500 μm and in the inset,
5 μm.