iScience (Apr 2024)

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

  • Hongyi Li,
  • Bei Li,
  • Wenqi Luo,
  • Xi Qi,
  • You Hao,
  • Chaozhi Yang,
  • Wenqing Li,
  • Jiazheng Li,
  • Zhen Hua,
  • Tan Guo,
  • Zhijian Zheng,
  • Xue Yu,
  • Lei Liu,
  • Jianping Zhao,
  • Tiantian Li,
  • Dahai Huang,
  • Jun Hu,
  • Zongmin Li,
  • Fang Wang,
  • Hua Li,
  • Chao Ma,
  • Fusui Ji

Journal volume & issue
Vol. 27, no. 4
p. 109407

Abstract

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Summary: 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.

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