Cavallari Eleonora, Lorenzi Elena, Di Gregorio Enza, Ferrauto Giuseppe, Aime Silvio, Vallortigara Giorgio, Bifone Angelo
Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.
Center for Mind/Brain Sciences, University of Trento, Rovereto (TN), Italy.
J Cereb Blood Flow Metab. 2025 May;45(5):977-988. doi: 10.1177/0271678X241309783. Epub 2024 Dec 24.
This study presents the first in vivo measurement of transcytolemmal water exchange in the brain using a novel Magnetic Resonance technique. We extend previous applications of Chemical Exchange Saturation Transfer (CEST) to examine water exchange across cellular membranes in late-stage chicken embryo brains. The immature blood-brain barrier at this stage allows Gadolinium-Based Contrast Agents (GBCAs) to penetrate the brain's interstitial space, sensitizing the CEST effect to water exchange between intra- and extracellular environments. Exchange rates were measured in the awake brain and under different anaesthetic regimens, including isoflurane and ketamine/xylazine. Results show that brain water exchange is dominated by activity-dependent mechanisms, with anaesthesia reducing exchange rates by over an order of magnitude. These findings suggest that anaesthetics may impact neuronal and glial function by interfering with active transport mechanisms, potentially altering brain water homeostasis. This study highlights the utility of CEST MRI for studying dynamic biological processes in vivo.
本研究首次使用一种新型磁共振技术对大脑中的跨细胞膜水交换进行了体内测量。我们扩展了化学交换饱和转移（CEST）的先前应用，以研究晚期鸡胚大脑中跨细胞膜的水交换。此阶段不成熟的血脑屏障允许基于钆的造影剂（GBCAs）穿透大脑的间质空间，使CEST效应对细胞内和细胞外环境之间的水交换敏感。在清醒大脑以及不同麻醉方案（包括异氟烷和氯胺酮/甲苯噻嗪）下测量了交换率。结果表明，大脑水交换主要由活动依赖机制主导，麻醉使交换率降低了一个多数量级。这些发现表明，麻醉剂可能通过干扰主动转运机制影响神经元和神经胶质功能，潜在地改变大脑水稳态。本研究突出了CEST磁共振成像在体内研究动态生物学过程中的实用性。
