Development of intimal thickening in superficial temporal arteries in patients with moyamoya disease.

To investigate the possible mechanism of neointimal formation in Moyamoya disease, we histologically examined the superficial temporal arteries and also investigated cultured smooth muscle cells (SMCs) from the arteries. Intimal thickening of the scalp arteries developed significantly at an early age in Moyamoya patients compared with control subjects. The histopathological findings of the neointima in scalp arteries were almost similar to those in intracranial arteries in Moyamoya patients. SMCs cultured from Moyamoya arteries responded significantly less to serum mitogens, especially to platelet derived growth factor (PDGF), than those of control patients, the finding of which was explained by the reduced number of PDGF receptor on Moyamoya SMCs. Our findings indicate the presence of systemic factors that promote migration and proliferation of SMCs from the media to the intima in Moyamoya disease. Our results suggest that alteration in vascular cells may contribute to the development of intimal thickening in Moyamoya disease.