Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA059

Poster Communications

A free-fluid transport pathway of fibrous connective tissues connecting the extremity end with the heart surfaces in a human gross anatomic study

H. Lee2, C. Yang5, F. Wang1, M. Chen5, F. Ji1, L. Xu5, N. Wang3, W. Liu4, D. Zhang3, Z. Ao4, L. Dai4, S. Su3, C. Ma3, D. Han4, H. Li6

1. Cardiology department, Beijing Hospital, Beijing, China. 2. Cardiology Department, Beijing Hospital, Beijing, China. 3. Department of Human Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, Peking Union Medical Collage, Beijing, China. 4. National Center for Nanoscience and Technology, Beijing, China. 5. Beijing Hospital, Beijing, China. 6. Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China.

  • Fig. 1. The fluorescent pathway and lymphatic vessels in right hand of two cadavers (A and B). A1, a fluorescent pathway originated from the injection point and was clearly seen on the skin. A2 showed the hypodermic tissues of the inner side of A1 that were significantly stained by fluorescein. There was a venous vessel pointed by the arrow head in A2. A3 was the frozen section of A2 and displayed both the dermis and the hypodermis tissues were stained by fluorescein. B showed the collecting lymphatic vessels (pointed by arrows) near the venous vessels (pointed by arrow heads). These pictures displayed the fluorescent pathway was neither the vein nor the lymphatic vessel.

A pathway of oriented fibrous connective tissues was revealed by fluorescein from ankle dermis, which argued against that free-fluid be entrapped within interstitium. Here, we speculate oriented fibrous tissues constitute a free-fluid transport pathway, connecting the distal end of extremities with fibrous tissues on heart, and verify this conjecture in human cadavers. 14 human cadavers were tested from 2016 to 2018. To visualize free-fluid pathway, 0.2ml fluorescein sodium was injected into distal end of right thumb of 10 subjects to observe fluorescein movements for 2.5 hrs firstly. Secondly, continuous chest compressions were performed right on heart for subsequent 2.5hrs by automatic chest compressions device with120bpm. The fluorescent pathways in right hand, forearm, upper arm, axilla and thorax were dissected layer-by-layer. Interesting samples were studied by histological methods. Another 3 subjects were injected by a paramagnetic tracer. The other 1 subject was injected by India ink for lymphatic vessels. There was only local confusion of fluorescein around injection point during first 2.5hrs of 10 subjects. After 2.5hrs repeated chest compressions, a longitudinally fluorescent pathway from thumb to heart surfaces was found in 7 subjects, but not in the 3 subjects with severe cachexia. By layered dissection, fluorescein pathways in hand and forearm was clearly seen in dermis, hypodermis, fascia on tendon or muscles, superficial tissues surrounding veins. In cubital fossa, upper arm, axilla and thorax, fluorescein pathways stained superficial tissues surrounding cephalic vein, axillary sheath around axillary vein, outer walls of superior vena cava, superficial tissues on right atrium. The transport course of fluorescein coincided with MRI findings. By histological analysis, fluorescent pathways were fibrous connective tissues and NOT blood or lymphatic vessels. By microCT and laser confocal microscopy, the intrinsic architecture of fluorescent pathway was longitudinally running fibers, upon which, free-fluid could flow and be visualized by fluorescein. Together with explorations on interstitium for decades, the anatomic studies testified a systemic free-fluid transport pathway of fibrous connective tissues, connecting superficial tissues of extremity end with a visceral organ. The intrinsic meshwork of fibrous connective tissues over the whole body probably constitute a huge interfacial transport system of body fluid between vascular conduits and cells. Both their interfacial dynamics and physiological/pathophysiological functions require extensive studies in life science.

Where applicable, experiments conform with Society ethical requirements