Grubb Søren
Department of Neuroscience and Center for Translational Neuromedicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Vasc Biol. 2023 Dec 1;5(1). doi: 10.1530/VB-23-0011. Print 2023 Jan 1.
Neurons communicate with vasculature to regulate blood flow in the brain, a process maintained by the neurovascular unit (NVU). This interaction, termed neurovascular coupling, is believed to involve astrocytes or molecules capable of traversing the astrocytic endfeet. The precise mechanism, however, remains elusive. Using large 3D electron microscopy datasets, we can now study the entire NVU in context of vascular hierarchy. This study presents evidence supporting the role of precapillary sphincters as a nexus for neurovascular coupling and endothelial transcytosis. It also highlights the role of fibroblast-synthesized collagen in fortifying first-order capillaries. Furthermore, I demonstrate how astrocytic endfeet establish a barrier for fluid flow and reveal that the cortex's microvasculature is semicircled by an unexpected arrangement of parenchymal neuronal processes around penetrating arterioles and arterial-end capillaries in both mouse and human brains. These discoveries offer insights into the NVU's structure and its operational mechanisms, potentially aiding researchers in devising new strategies for preserving cognitive function and promoting healthy aging.
神经元与血管系统相互作用以调节大脑中的血流，这一过程由神经血管单元（NVU）维持。这种相互作用，即神经血管耦合，被认为涉及星形胶质细胞或能够穿过星形胶质细胞终足的分子。然而，确切的机制仍然难以捉摸。利用大型三维电子显微镜数据集，我们现在可以在血管层级的背景下研究整个神经血管单元。这项研究提供了证据，支持毛细血管前括约肌作为神经血管耦合和内皮转胞吞作用的连接点的作用。它还强调了成纤维细胞合成的胶原蛋白在强化一级毛细血管方面的作用。此外，我展示了星形胶质细胞终足如何为流体流动建立屏障，并揭示了在小鼠和人类大脑中，皮质的微血管被围绕穿透小动脉和动脉端毛细血管的实质神经元过程的意外排列半包围。这些发现为神经血管单元的结构及其运作机制提供了见解，可能有助于研究人员设计新的策略来保持认知功能和促进健康衰老。
