Caspase-3-dependent Apoptosis in Middle Cerebral Arteries in Patients with Moyamoya Disease

Moyamoya disease (MMD) is a cerebrovascular occlusive disease characterized by progressive stenosis or occlusion at the distal ends of bilateral internal arteries. In MMD, a decreased number of medial smooth muscle cells in these vessels was previously reported. In this study focusing on the mechanism of remodeling in intracranial arterial walls of patients with MMD, we first collected tiny pieces of the wall of the middle cerebral artery (MCA) from patients with MMD and then analyzed them by immunohistochemical methods.Ten patients underwent surgical procedures for the treatment of standard indications of MMD at Kyoto University Hospital. Specimens of MCA were obtained from these MMD patients during the surgical procedures. MCA samples were also obtained in the same way from control patients. The samples were analyzed by immunohistochemical methods.MCA specimens from MMD patients had a thinner media than control specimens. Immunoreactivities indicating single-stranded DNA and cleaved caspase-3 were higher in MMD samples than in control ones and were located in the smooth muscle cells of the media.Our results indicate that apoptosis, as evidenced by activated caspase-3, occurred in the media of the MCA of MMD patients. Thus, the MCA specimens from MMD patients had thinner vascular walls than specimens from controls.