In vivo demonstration of blood-brain barrier impairment in Moyamoya disease

BackgroundMoyamoya disease (MMD) is a cerebrovascular disorder characterized by fragile vascular system. Previous studies suggested that the blood-brain barrier (BBB) destabilizing cytokine angiopoietin-2 plays a critical role in increasing vascular plasticity and endothelial disintegration in MMD. The aim of this study was to assess cerebrovascular integrity in vivo in patients affected by MMD.MethodsWe retrospectively analyzed 11 patients that underwent bypass for MMD (MMD group), 11 patients that underwent bypass for atherosclerotic cerebrovascular disease (ACVDcontrol group I), and 5 patients that underwent clipping for unruptured aneurysms (non-ischemiccontrol group II). Sodium fluorescein (NaFL) extravasation was evaluated during videoangiography when checking for bypass patency. A grading system (0, +, ++, +++) was used to define the extent of extravasation. Frequency and intensity of leakage was compared among different groups.ResultsNaFL extravasation appeared in 10/11 (91%) patients with MMD and in 8/11 (73%) patients with ACVD during bypass procedures. Extravasation was observed in none of the patients undergoing clipping for unruptured aneurysms. Although both chronic ischemic patient groups showed a comparably high incidence of NaFL extravasation, the MMD group was characterized by a much greater intensity of NaFL extravasation (grade +++ in 82%) than the ACVD group (grade +++ in 27%, p<0.05).ConclusionsWe demonstrate blood-brain barrier impairment in MMD patients for the first time in vivo. This may be due to mechanisms intrinsic to the unique pathology of MMD, probably explaining the higher association with hemorrhage and post-operative hyperperfusion.