Tu Jian, Stoodley Marcus A, Morgan Michael K, Storer Kingsley P
Prince of Wales Medical Research Institute, University of New South Wales, New South Wales, Australia.
Neurosurgery. 2006 May;58(5):961-70; discussion 961-70. doi: 10.1227/01.NEU.0000210248.39504.B5.
The ultrastructure of perinidal capillaries in cerebral arteriovenous malformations (AVMs) was examined to clarify their pathomorphological features.
Fifteen AVM specimens were dissected and divided into perinidal and intranidal groups and processed for ultrastructural study immediately after surgical removal. Eleven of the patients had presented with hemorrhage. Tissue from four normal controls was also studied. Electron microscopy was used to compare features of the blood-brain barrier and endothelial cells (ECs) of capillaries in perinidal, intranidal, and controls.
Perinidal capillaries demonstrated abnormal ultrastructure of the blood-brain barrier with no basement membranes and astrocytic foot processes. ECs had fenestrated luminal surfaces. Large gaps were observed at endothelial intercellular junctions. ECs contained numerous filopodia, large numbers of cytoplasmic processes, numerous micropinocytotic vesicles, and the cytoplasm contained more filaments than those observed in controls. Pericytes were rich in pinocytotic vesicles, vacuoles, and filaments. Their processes were in close contact with ECs. Weibel-Palade bodies were present in perinidal ECs.
The absence of blood-brain barrier components in perinidal capillaries may contribute to extravasation of red blood cells into the surrounding brain in the absence of major hemorrhage and explain the gliosis and hemosiderin occasionally seen around AVMs. Cellular differentiation and proliferation in perinidal capillaries should be included in a systematic study aimed at a better understanding of the mechanisms underlying the recurrence of surgically removed AVMs.
研究脑动静脉畸形（AVM）病灶周围毛细血管的超微结构，以明确其病理形态学特征。
解剖15例AVM标本，分为病灶周围组和病灶内组，手术切除后立即进行超微结构研究。其中11例患者有出血表现。还研究了4例正常对照的组织。采用电子显微镜比较病灶周围、病灶内毛细血管以及对照毛细血管的血脑屏障和内皮细胞（ECs）特征。
病灶周围毛细血管显示出血脑屏障超微结构异常，无基底膜和星形胶质细胞足突。内皮细胞腔面有窗孔。在内皮细胞间连接处观察到较大间隙。内皮细胞含有大量丝状伪足、大量细胞质突起、大量微吞饮小泡，且细胞质中含有的细丝比对照组更多。周细胞富含吞饮小泡、空泡和细丝。其突起与内皮细胞紧密接触。病灶周围内皮细胞中有Weibel-Palade小体。
病灶周围毛细血管中血脑屏障成分的缺失可能导致红细胞在无大出血情况下渗入周围脑组织，并解释了AVM周围偶尔出现的胶质增生和含铁血黄素沉积。在旨在更好地理解手术切除AVM复发机制的系统研究中，应纳入病灶周围毛细血管的细胞分化和增殖情况。
