The Thoracic Lymphatic Vasculature: Interorgan Strategies to Achieve an Optimal Tissue Function

In thoracic tissues, the lymphatic vasculature not only contributes to fluid and solute homeostasis but also plays a critical role in shaping overall tissue physiology. Although the general morphology of lymphatic vessels and their organization within the vascular circuit are largely conserved inter-organs, thoracic lymphatics exhibit highly specialized structural features, such as the presence of stomata and large lacunae, which are exclusively found in pleural and peritoneal mesothelia. These distinct anatomical specializations characterize thoracic lymphatics, which extensively supply organs such as the lung and the heart, as well as serosal compartments including the pleural space and the suprahepatic subdiaphragmatic peritoneal regions, and are associated with equally specialized mechanisms that sustain lymph formation and propulsion. While lymph flow in all tissues may rely on spontaneous contraction of the lymphatic muscles located within the vessel wall and/or on extrinsic tissue motion, the thoracic lymphatic vasculature displays an exceptional diversity of morphological and functional solutions that allow these mechanisms to be exploited with high efficiency, in close adaptation to local anatomical and mechanical environments. Accordingly, this Review focuses on the inter-organ strategies developed by thoracic lymphatics to match local drainage requirements, highlighting how structural specialization and mechanical integration with surrounding tissues optimize lymphatic function and, ultimately, overall tissue performance.