Identification of Primo Vascular System in Murine Tumors and Viscera

In the past decade, researchers at Seoul National University of South Korea have validated the existence of the primo-vascular system using animal models, which was originally reported by Bonghan Kim in the 1960s. After exploring a variety of dye stains, Kwang-Sup Soh, et al. found that trypan blue is an effective dye for staining structures of the primo vessels and nodes. Most of the studies reported so far have used relatively large animal models such as rabbits. In this study, we explored the potential of visualizing primo-vascular system in murine models. As compared to conventional models used for primo-vascular studies, murine models are more versatile and affordable. In mice, we found primo vessels extended to and from abdominal viscera, often disappearing in layers of adipose tissue before resurfacing in a more distal region. In addition, we found potential primo-vascular structures on the tumor surface. These structures were loosely attached to the surface of the tumor and some segments appear to be within the clear serosal tissue or invading into the tumor. The experience of identifying primo-vascular system in rodents empowers us to investigate the detailed relationship of primo-vessels and cancer in future studies. A breakthrough in elucidating the complete anatomical and physiological description of the primo-vascular system holds great promise of unraveling the molecular basis of various human diseases.