The Quantitive Analysis of Cell Motility in Cultures of Smooth Muscle Cells, Endothelial Cells and Monocyte/Macrophages in Individual and Co-Culture Systems, Using Time-Lapse Video-Microscopy in Correlation with Progression of Atherosclerosis

Summary

Time-lapse video-microscopy was used to analyse smooth muscle cell migration, proliferation and morphology. While earlier experiments with smooth muscle cells obtained from acute hypertensive animals had shown activated cell migration and proliferation, longer duration of 6 weeks hypertension resulted in a reduction of cellular proliferation and a normalisation of migration. The cells became larger and their metabolism may have increased. It is proposed that vascular wall cells are activated during the early phase of atherogenesis in their migratory and proliferative behaviour during a short phase of up to 3 weeks, while longer duration results in an activation of their metabolism.

In addition, the interaction of leucocytes and endothelial cells was analysed in a co-culture system. Isolated granulocytes or monocytes/macrophages were added to confluent endothelial cell cultures. The migratory behavior of the blood cells was subsequently analysed using video direct visualization and morphometry. Using this technology the active migration of blood cells through the confluent endothelial layer in both directions could be shown. All monocytes migrated from the top of the endothelial layer underneath the endothelial cells and remained there. Granulocytes showed a differentiated migration pattern. One third remained on top of the endothelium, about 50% passed through the endothelium and remained there, the rest changed sides several times, up to 5 times per hour. The migratory speed of granulocytes was 1166 µm/h, about twice as fast as the speed of monocytes at 608 µm/h. The differentiation between the migratory speed of granulocytes on top or underneath the endothelial cells revealed a marked acceleration underneath the endothelial cells with a speed of 1519 µm/h compared to 671 µm/h on top of the endothelium. These results could be interpreted to mean that special extracellular matrix components produced by the endothelial cells activate the migratory behavior of blood cells.