Regulation of interstitial fluid flow in adventitia along vasculature by heartbeat and respiration

• Published in: iScience Vol. 27; no. 4; p. 109407
• Main Authors: Li, Hongyi, Li, Bei, Luo, Wenqi, Qi, Xi, Hao, You, Yang, Chaozhi, Li, Wenqing, Li, Jiazheng, Hua, Zhen, Guo, Tan, Zheng, Zhijian, Yu, Xue, Liu, Lei, Zhao, Jianping, Li, Tiantian, Huang, Dahai, Hu, Jun, Li, Zongmin, Wang, Fang, Li, Hua, Ma, Chao, Ji, Fusui
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.04.2024; Elsevier
• Subjects: Animal physiology; Biological sciences; Physiology; Biological sciences; Physiology; Animal physiology
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2024.109407

Converging studies showed interstitial fluid (ISF) adjacent to blood vessels flows in adventitia along vasculature into heart and lungs. We aim to reveal circulatory pathways and regulatory mechanism of such adventitial ISF flow in rat model. By MRI, real-time fluorescent imaging, micro-CT, and histological analysis, ISF was found to flow in adventitial matrix surrounded by fascia and along systemic vessels into heart, then flow into lungs via pulmonary arteries and back to heart via pulmonary veins, which was neither perivascular tissues nor blood or lymphatic vessels. Under physiological conditions, speckle-like adventitial ISF flow rate was positively correlated with heart rate, increased when holding breath, became pulsative during heavy breathing. During cardiac or respiratory cycle, each dilation or contraction of heart or lungs can generate to-and-fro adventitial ISF flow along femoral veins. Discovered regulatory mechanisms of adventitial ISF flow along vasculature by heart and lungs will revolutionize understanding of cardiovascular system. [Display omitted] •Synergistic actions of heart and lungs generate a to-and-fro flow of adventitial ISF•Heartbeat and respiration regulate adventitial ISF to flow along vasculature•ISF flows in “matrix-membranes channels” rather than a vascular conduit•Cardiovascular system can also transport and regulate ISF through the body Biological sciences; Physiology; Animal physiology