1:Biodonostia Institute

The lymphatic system is crucial for maintaining homeostasis, nutrient transport, and immune surveillance within adult tissues, and is also relevant in the promotion of cancer metastasis. Lymphatic endothelial progenitor cells (LEPCs) promote lymphangiogenesis in vitro and in vivo, and represent a suitable cell source for the in vitro engineering of lymphatic vessels. Although LEPC express transmembrane glycoproteins such as Podoplanin, CD31 and LYVE-1, the optimal strategy for the extraction of LEPCs from solid tissues and their subsequent use for cellular therapy remains to be established. In this work, we aimed to establish a reliable source of LEPCs to be used in tissue engineering and cell therapy, as well as characterize their lymphangiogenic behaviour in vitro. To this end, primary cells were extracted from the bone marrow, dermis and vascular stromal fractions (VSF) of C57BL/6 adult mice (N=22) and analysed for the expression of Podoplanin, CD31 and LYVE-1  by flow cytometry, at day 0 and after 4 days of culture in the presence of lymphangiogenic medium. The results showed that VSF and bone marrow outperformed the dermis as the optimal tissue sources of LEPCs. The establishment of a reliable LEPC tissue source will favour the development of patient-specific cellular therapies.