ELM: a new, simple, and economic assay to measure motility of lymphatic endothelial cells

Background. Relative few attempts have been made to set up an assay that allows the measurement of lymphatic endothelial cells (LECs) motility. Nowadays the most widely used methods involve adaptation of the Boyden chamber method or the wound scratch assay, both of them showing some limitations due to long and expensive setup and high variability. Methods and Results. We propose a new, economic, and Easy to setup LEC Motility (ELM) assay that will contribute to the study of lymphangiogenesis. The experimental set-up consists in extending the coating of the flask with extracellular matrix (ECM) proteins also at the area opposite to the cap, where the LECs will be initially seeded at various densities. The day after, the flasks will be inclined at an angle of about 20 degrees in order to cover the entire coated surface. 24 hours later, flasks will be moved to the standard position, and the motility of the cells will be easily observed. Using the ELM assay we were able to compare the motility rate of LECs isolated from different origins, or seeded on different substrates. Conclusion. We propose the use of a new method to evaluate the motility of LECs: the ELM assay. This cost-effective analysis has several advantages: can be easily setup in any cell biology laboratory, can be carried out rapidly, and allows the monitoring of cellular motility for a long period.