Fig. 5

Monocyte circulation facilitates increased transmigration and adhesion compared to static conditions. (a) 3D volume reconstruction of confocal image stacks showing adhered (white) and transmigrated (orange) monocytes after 24 h of either static culture or circulation (50 μl/min) in fluidic hToC devices with endothelial barriers. 100 ng/ml MCP-1 was added to the bottom channel and compared to a control condition without MCP-1. (b) Quantification of transmigrated monocytes, normalized over the total image volume. Results demonstrate increased levels of monocyte transmigration in response to MCP-1 in the circulating condition, compared to non-significant changes in static culture. (c) xy slice at the membrane displaying monocytes adhered to the endothelium. (d) Quantification of adhered monocytes, normalized over the total image area. Circulating flow resulted in a significant increase (p = 0.0248) in monocyte adhesion. (e) Confocal images of adhered (white) and transmigrated (orange) monocytes after 24 h of flow (50 μl/min) in fluidic hToC devices with or without an endothelial barrier. In the corresponding phase images, the -EC condition displays the membrane with 5 µm pores and a collagen backfill, and the + EC condition demonstrates a representative EC monolayer prior to the introduction of monocytes. (f) Quantification of the total number of transmigrated monocytes, exhibiting a significant increase in monocyte transmigration in devices with an EC monolayer. One-way ANOVA with Tukey’s post-hoc test was used, *p < 0.05, ***p < 0.001.