Heistad D D, Marcus M L
Blood Vessels. 1979;16(5):225-38. doi: 10.1159/000158209.
The media of arteries is virtually avascular. Thus, oxygen and nutrients must reach the cells of the media by diffusion from the lumen of the vessel and from adventitial vessels. The thickness of the thoracic aorta of man and dog exceeds the effective diffusion distance of oxygen, but nutrition is supplemented by vasa vasorum which enter into the outer layers of the media. Occlusion of vasa vasorum in dogs produces medial necrosis, which indicates that these vessels are essential for the nourishment of the aorta. Recently the microsphere method has been used to provide the first measurements of blood flow through vasa vasorum. There is substantial flow to the outer layers of media of the thoracic aorta in dogs, with virtually no blood flow in the inner layers. The vessels are very responsive to physiological stimuli: they dilate during infusion of adenosine and constrict during stimulation of sympathetic nerves. During acute increases in arterial pressure, blood flow to the media decreases probably from distortion of vasa vasorum. Vasa vasorum may play role in disease states. Insufficient blood flow through vasa vasorum may contribute to medial necrosis of the aorta and to aortic atherosclerosis. A role of vasa vasorum in aortic changes in hypertension and other vascular diseases merits further study.
动脉的中膜实际上是无血管的。因此，氧气和营养物质必须通过从血管腔和外膜血管扩散才能到达中膜的细胞。人和狗的胸主动脉厚度超过了氧气的有效扩散距离，但有进入中膜外层的血管滋养补充营养。阻断狗的血管滋养血管会导致中膜坏死，这表明这些血管对主动脉的营养至关重要。最近，微球法已被用于首次测量通过血管滋养血管的血流量。狗的胸主动脉中膜外层有大量血流，而内层几乎没有血流。这些血管对生理刺激非常敏感：在输注腺苷时扩张，在交感神经刺激时收缩。在动脉压急性升高期间，流向中膜的血流量可能因血管滋养血管的扭曲而减少。血管滋养血管可能在疾病状态中起作用。通过血管滋养血管的血流不足可能导致主动脉中膜坏死和主动脉动脉粥样硬化。血管滋养血管在高血压和其他血管疾病的主动脉变化中的作用值得进一步研究。
