Angioarchitecture and CD133^+ tumor stem cell distribution in intracranial hemangiopericytoma A comparative study with meningioma

Angioarchitecture plays an important role in the malignant development of intracranial hemangiopericytoma. It remains poorly understood whether high frequency of hemorrhage during clinical surgery for intracranial hemangiopericytoma is associated with angioarchitecture. The present study utilized hematoxylin-eosin staining, and immunohistochemical staining with epithelial membrane antigen, vimentin, CD34, von Willebrand factor （vWF） and CD133 to observe characteristics of angioarchitecture. In addition, silver stains were used to demonstrate changes in reticular fibers in the wall of vessel channels in intracranial hemangiopericytoma and meningioma. Five patterns of angioarchitecture were identified in intracranial hemangiopericytoma, namely tumor cell islands, vasculogenic mimicry, mosaic blood vessels, sprouting angiogenesis, and intussusceptive angiogenesis. Several CD133＋ tumor cells were found to form tumor cell islands. A connection between vWF ^＋ and vWF channels was detected in the pattern of intussusceptive angiogenesis, and some vimentin^＋ tumor cells were embedded in the periodic acid-Schiff positive channel wall. Incomplete threads of reticular fibers formed the walls of larger pseudo-vascular channels and some tumor clumps or scattered tumor cells were detected ＂floating＂ in them. The angioarchitecture, specific markers and reticular fibers of intracranial hemangiopericytoma were significantly different from meningioma. Angioarchitecture provides a functional vascular network for vascular evolution in intracranial hemangiopericytoma and contributes to significant intra-operative bleeding.

Synchrotron Radiation-Based Three-Dimensional Visualization of Angioarchitectural Remodeling in Hippocampus of Epileptic Rats

Characterizing the three-dimensional (3D) morphological alterations of microvessels under both normal and seizure conditions is crucial for a better understanding of epilepsy. However, conventional imaging techniques cannot detect microvessels on micron/sub-micron scales without angiography. In this study, synchrotron radiation(SR)-based X-ray in-line phase-contrast imaging (ILPCI)and quantitative 3D characterization were used to acquire high-resolution, high-contrast images of rat brain tissue under both normal and seizure conditions. The number of blood microvessels was markedly increased on days 1 and 14, but decreased on day 60 after seizures. The surface area, diameter distribution, mean tortuosity, and number of bifurcations and network segments also showed similar trends. These pathological changes were confirmed by histological tests. Thus, SR-based ILPCI provides systematic and detailed views of cerebrovascular anatomy at the micron level without using contrast-enhancing agents. This holds considerable promise for better diagnosis and understanding of the pathogenesis and development of epilepsy.

Relationships between hemorrhage, angioarchitectural factors and collagen of arteriovenous malformations

Objective While associations between the angioarchitecture of arteriovenous malformations （AVMs） in the brain and pathological features have been described, here we investigated the relationship between the angioarchitecture, the pathological features of the vessel wall, and hemorrhagic events. Methods The study was conducted on 43 patients： 16 with ruptured AVM （rAVM）, 15 with non-ruptured AVM （nrAVM）, 6 with craniocerebral trauma （control） and 6 with epilepsy （control）. The diagnosis of AVM was confirmed by preoperative digital subtraction angiography. Tissues were stained with hematoxylin and eosin and Masson＇s trichrome （for collagen fibers） to evaluate the vessel wall structure and endothelial integrity. The content and distribution of collagen types I and III in the vessel wall were assessed by immunohistochemical staining. Results In the nrAVM group, the nidus had more draining veins than the rAVM group （P 〈0.05）. Severely damaged endothelial cells, significantly fewer smooth muscle cells in the media, and hyperplasic type-I and -III collagen fibers were found in the rAVM group. The content of collagen types I and III in rAVMs was higher than that in the nrAVM （P 〈0.05） and control groups （P 〈0.01）. Conclusion There is an association between angioarchitectural features such as the number of draining veins and the pathological structure of the AVM wall. These abnormalities may contribute to AVM rupture.