Early arteriosclerotic changes of the carotid artery wall induced by electrostimulation. A study by scanning and transmission electron microscopy.

Using the method described by Betz and Schlote, 1979, it is possible to produce local smooth muscle cell proliferation in the intima of arterial walls by electrostimulation. If local electrostimulation is combined with a high cholesterol diet, atheromatous plaques arise at the anodal region of the stimulation electrodes. This is achieved by implanting a cuff around the common carotid artery of rabbits. By means of the electrodes which are situated in the cuff, DC-impulses are applied. The advantages of the described method are the following: the site of alteration can be determined, the stimulation intensity can be exactly adjusted and an initially induced coarse endothelial injury can be avoided. In this study the very first morphological changes have been observed by scanning and transmission electron microscopy. After an initial enlargement of the subendothelial space a migration of myocytes into this space is seen followed by a transformation of smooth muscle cells into modified cells. They develop a more active metabolism, undergo mitosis and produce proliferations after 4 days of stimulation. The development of the plaques shows a striking agreement with the results of other authors, although the used methods are completely different. Therefore, it can be assumed that the walls of arteries respond to various types of alterations with an unspecific and uniform reaction. Concerning our results, at least, an endothelial desquamation is not a prerequisite for a proliferative reaction of arterial smooth muscle cells. It can be concluded that, at the beginning of the arteriosclerotic development, a functional event predominates, which depends in our experiments on the electrical charge applied to the artery wall at the anode. Because of its functional character, this triggering mechanism cannot be investigated by morphological methods alone.