Pathomorphological Study on the Changes of Human Intra-abdominal Umbilical Artery with Aging

The human intra-abdominal umbilical artery by the ligation of the umbilical cord soon after the birth becomes a lateral umbilical ligament in adults. The specimens of the human intra-abdominal umbilical artery obtained from cases ranging in age from 18 weeks of menstrual age to 74 years old were examined light and electron microscopically in search of changes as part of the series of study on the vascular aging phenomena. On the other hand, the vein, the artery in the vulval cyst wall, and the pulmonary vessels of the cases of bronchiectasis and lung cancer were also examined for comparison. In the adventitia in the umbilical and intermediate parts of the intra-abdominal umbilical artery, smooth muscle cells appeared and then became involuted. Since smooth muscle cells were observed in the adventitia of the above artery and pulmonary vessels examined, the artery might react to produce smooth muscle cell bundles in the adventitia. Moreover, since the vein physiologically contains smooth muscle cell bundles, the presence of smooth muscle cell bundles in the artery may suggest that the artery became similar to the vein. In the media of the umbilical and intermediate parts, elastosis was noted and smooth muscle cells were artophied. Complete obliteration was barely induced so as to see patent lumen even in aged cases. The narrowing of the lumen was due to intimal thickening and thrombi. The internal iliac arterial part showed only intimal thickening and no other remarkable changes