Non-Invasive Assessment of Lymphatic Pumping Pressure in a Rat Tail Model Utilizing Near-Infrared Imaging

The lymphatic vasculature consists of a network of vessels that promote unidirectional transport of fluid, proteins, and cells from the interstitium back into the blood, providing functions essential for maintaining fluid balance, immune cell trafficking, and lipid absorption from the intestine. The lymphatics generate flow through both extrinsic pumping mechanisms, such as contraction of surrounding skeletal muscle, and through the intrinsic contractility of each lymphatic vessel unit known as a lymphangion. Specialized lymphatic muscle, working in coordination with uni-directional valves separating each lymphangion, serves to contract up to 80% of the vessel diameter and drive flow from the interstitium back to the venous circulation.