Assessment of aquaporin-4 role in brain activity detected by diffusion magnetic resonance imaging

Autor: Yagüe, Balbino, Guadilla, Irene, Cerdán, Sebastián, Lizarbe, Blanca, López-Larrubia, Pilar
Rok vydání: 2021
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
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Popis: Trabajo presentado en el 1st ISMRM Iberian Chapter Annual Meeting, celebrado en Portugal del 16 al 17 de junio de 2021.
Aquaporin-4 (AQP4) is a transmembrane water channel highly expressed in central nervous system, regulating fluid exchange [1] by water transport between two sides of plasmatic membrane, and depending on concentration gradients of solutes [2]. Previously, we have shown that functional diffusion MRI can detect cellular swelling associated to glucose uptake [3]. On these grounds, role of APQ4 in this process was studied. AQP4 inhibitor TGN-020 [4] was used to assess cerebral changes after glucose bolus administration in C57BL6/J adult male mice with TGN administration plus glucose, saline administration plus glucose, and saline administration only (Figure 1). Diffusion tensor imaging studies were acquired in a 7T equipment and mean diffusivity (MD) and fractional anisotropy (FA) were measured in hypothalamus, hippocampus, and cortex regions. In a parallel cohort, we acquired 1H High Resolution Magic Angle Spinning (HRMAS) spectra in a 11.7T system. Glucose group experienced a decreased in MD 30 minutes after glucose injection. However, this response seems to be partially inhibited in TGN group, especially in hypothalamus. Metabolic studies show a decreased glutamate concentration in cortex and hippocampus of TGN group, as compared to glucose and control groups, while GABA concentration is higher. Glucose administration induces a cerebral response detectable with DTI. Use of TGN inhibits AQP4 and partially avoids its function, noting that AQP4 is involved in cellular volume regulation. Metabolic results correspond with an alteration of the glutamate cycle due to AQP4 obstruction, that yield a net increase of this metabolite concentration. (247 of 250 words)
Databáze: OpenAIRE
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