The Experimental Study on Causal Genesis of Moyamoya Disease

-Correlation with immunological reaction and sympathetic nerve influence for vascular changes-

Abstract

Initial pathological finding in Moyamoya disease is stenotic change at the carotid fork due to some unknown causes. Many discussions have been made on the causal genesis of this change at the carotid fork, but there have been no proof on them nor any experimental study. Based on our study of 100 cases of this disease, we have found that many patients experienced chronic inflammation above the neck, i. e. chronic tonsillitis, neck phlegmon, and that pathological changes in autopsy cases are similar to those of angitis due to immunological reaction such as panarteritis nodosa.
From these facts, we presumed that the causal genesis of Moyamoya disease should be certain immunological arteritis resulted from inflammation. In order to prove our presumption, foreign protein of other animals was injected to mongrel dogs repeatedly for certain period, so that hyperimmune state was obtained. Serial arterial specimen of both groups revealed similar arterial changes of this disease, such as exfoliation of the intima, thickening of the intimal wall, rupturing and winding of the lamina elastica interna, muscle layer necrosis of the media and formation of mural thrombus. These arterial changes were limitedly observed around the carotid fork, i.e. the terminal portion of the internal carotid artery, the proximal portion of the anterior and middle cerebral arteries and posterior communicating artery. It is also characteristic that the distal portion of cerebral arteries had no pathological changes. We supposed that the localized appearance of these pathological changes should have some correlation with autonomic nerve system originating from the superior cervical ganglion, which is easily affected by infected tonsil.
According to Reilly's phenomenon, stimulated sympathetic ganglion would give influences to the arteries innervated from the ganglion. In addition to that, anatomical innervation of the autonomic nervous system is very prominent especially around the carotid fork.
Based on these facts, in other group of dogs unilateral superior cervical ganglionectomy was carried out first, then foreign serum was injected to the residual superior cervical ganglion as well as to the whole body for general sensitization. In these dogs, less arterial changes on the side of ganglionectomy were observed. Therefore, it would be possible to have some correlation with cervical ganglion for the occurrence of arterial changes at the carotid fork. From the results of our experiments, our hypothesis on the causal genesis of this disease is as follows. Inflammation causes immune reaction and stimulate the superior cervical ganglion at the same time, so that the arteritis localized at the carotid fork are induced. Changes of arterial wall resulted from arteritis are organized, and then organic stenosis at the carotid fork progresses gradually.