Division of Neurotoxicology, HFT-132, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA.
Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
Mol Neurobiol. 2018 Jan;55(1):156-163. doi: 10.1007/s12035-017-0729-6.
The neurovascular unit (NVU) can be conceptualized as a functional entity consisting of neurons, astrocytes, pericytes, and endothelial and smooth muscle cells that operate in concert to affect blood flow to a very circumscribed area. Although we are currently in a "golden era" of bioengineering, there are, as yet, no living NVUs-on-a-chip modules available and the development of a neural chip that would mimic NVUs is a seemingly lofty goal. The sexually dimorphic nucleus of the preoptic area (SDN-POA) is a tiny brain structure (between 0.001~0.007 mm in rats) with an assessable biological function (i.e., male sexual behavior). The present effort was undertaken to determine whether there are identifiable NVUs in the SDN-POA by assessing its vasculature relative to its known neural components. First, a thorough and systematic review of thousands of histologic and immunofluorescent images from 201 weanling and adult rats was undertaken to define the characteristics of the vessels supplying the SDN-POA: its primary supply artery/arteriole and capillaries are physically inseparable from their neural elements. A subsequent immunofluorescent study targeting α-smooth muscle actin confirmed the identity of an artery/arteriole supplying the SDN-POA. In reality, the predominant components of the SDN-POA are calbindin D28k-positive neurons that are comingled with tyrosine hydroxylase-positive projections. Finally, a schematic of an SDN-POA NVU is proposed as a working model of the basic building block of the CNS. Such modules could serve the study of neurovascular mechanisms and potentially inform the development of next generation bioengineered neural transplants, i.e., the construct of an NVU neural chip.
神经血管单元（NVU）可以被概念化为一个由神经元、星形胶质细胞、周细胞、内皮和平滑肌细胞组成的功能实体，它们协同作用以影响非常局限的区域的血流。尽管我们目前正处于生物工程的“黄金时代”，但尚未有可用的活体 NVU 芯片模块，并且开发出模拟 NVU 的神经芯片似乎是一个高不可攀的目标。视前区正中核（SDN-POA）的性别二态性核是一个微小的脑结构（在大鼠中为 0.001~0.007 毫米），具有可评估的生物学功能（即雄性性行为）。目前的努力旨在通过评估其血管系统相对于其已知的神经成分来确定 SDN-POA 中是否存在可识别的 NVU。首先，对 201 只断奶和成年大鼠的数千张组织学和免疫荧光图像进行了彻底和系统的回顾，以定义供应 SDN-POA 的血管的特征：其主要供应动脉/小动脉和毛细血管与其神经元素在物理上是不可分离的。随后的一项针对α-平滑肌肌动蛋白的免疫荧光研究证实了供应 SDN-POA 的动脉/小动脉的身份。实际上，SDN-POA 的主要成分是与酪氨酸羟化酶阳性投射物混合的 calbindin D28k 阳性神经元。最后，提出了 SDN-POA 的 NVU 示意图作为 CNS 基本构建块的工作模型。这些模块可以用于研究神经血管机制，并为下一代生物工程神经移植的发展提供信息，即 NVU 神经芯片的构建。
