Disruption of the vascular barrier plays a central role in the onset and progression of diseases, including chronic kidney disease, (vascular) dementia, Alzheimer’s and atherosclerosis. Preventing the disruption or restoring the barrier is thus an attractive target for drug discovery. Here we show how to build 3-dimensional blood vessels that are exposed to important cues, including interaction with an extracellular matrix (ECM) and exposure to flow. To model inflammation blood vessels are exposed to cytokines leading to loss of barrier function, increased ICAM expression and increased attachment of monocytes. Other applications include studying angiogenesis, building a glomerulus or a blood-brain barrier.
- Formation of 96 blood vessels in the OrganoPlate®
- Real-time readout of loss of barrier function
- No artificial membranes; cells are directly against the extracellular matrix
- Immune cell adhesion is a measure for inflammation
An OrganoPlate® 2-lane has been used comprising 96 microfluidic devices. Each microfluidic device consists of two channels: an ‘perfusion’ channel and a ‘gel’ channel separated by a phaseguide (Figure 2a). Collagen-1 gel is seeded as extracellular matrix (ECM). After polymerization, the cells suspension is seeded in the perfusion channel (figure 2b ii). After adhesion of the cells, perfusion is started by placing the device on a the OrganoFlow® platform (figure 2b iii). In 48 hours the cells grow as a confluent monolayer against the collagen gel and channel walls, resulting in a microvessel with a perfusable lumen (figure 2b iv). 48 hr after cell seeding, a confluent vessel of endothelial cells is formed and an apical side (lumen) and basal side (Figure c).
Cells were exposed to concentration ranges of cytokines. Leakage of a FITC labeled dye allows to probe the integrity of the barrier function (Figure 3). Permeability was assessed after 24 hr exposure to IL1ß, IL8, INFy, RA, TNFα and VEGF in 3 different concentrations. This revealed dose dependent loss of barrier function for IL1ß and TNFα.
Further studies of TNFα exposure to blood vessel revealed increased ICAM-1 expression. Addition of monocytes resulted in a dose dependent increase in immune cell adhesion to the blood vessel wall (Figure 4).
See how bloodvessels are used to study angiogenesis.