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Main Authors: Mougel, Eloise, Palombo, Marco, Valette, Julien
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.16014
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author Mougel, Eloise
Palombo, Marco
Valette, Julien
author_facet Mougel, Eloise
Palombo, Marco
Valette, Julien
contents Lactate is crucial in the brain, as it is involved in neuronal activity and memory formation. This is thought to be related to the astrocyte-neuron lactate shuttle hypothesis (ANLS), which has been debated for 30 years, not least because it is difficult to measure lactate compartmentation and exchange in vivo. In particular, while ANLS requires transfer of lactate via the extracellular space, intracellular/extracellular exchange rate remains unknown. In this work, we propose to use time-dependent diffusion MRS to assess lactate exchange and lactate compartmentation in mouse brain gray matter in vivo. First, by comparing lactate time-dependent diffusivity and kurtosis with those of water and purely intracellular metabolites (which exhibit "fast" and "no" exchange signatures, respectively), we estimate that lactate exchange is slow (i.e. on the order of hundreds of milliseconds). Then, using biophysical models neglecting exchange, we estimate extracellular, neuronal and astrocytic lactate fractions compatible with the ANLS hypothesis.
format Preprint
id arxiv_https___arxiv_org_abs_2412_16014
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Probing lactate exchange and compartmentation in Gray Matter via time-dependent diffusion-weighted MRS
Mougel, Eloise
Palombo, Marco
Valette, Julien
Medical Physics
Lactate is crucial in the brain, as it is involved in neuronal activity and memory formation. This is thought to be related to the astrocyte-neuron lactate shuttle hypothesis (ANLS), which has been debated for 30 years, not least because it is difficult to measure lactate compartmentation and exchange in vivo. In particular, while ANLS requires transfer of lactate via the extracellular space, intracellular/extracellular exchange rate remains unknown. In this work, we propose to use time-dependent diffusion MRS to assess lactate exchange and lactate compartmentation in mouse brain gray matter in vivo. First, by comparing lactate time-dependent diffusivity and kurtosis with those of water and purely intracellular metabolites (which exhibit "fast" and "no" exchange signatures, respectively), we estimate that lactate exchange is slow (i.e. on the order of hundreds of milliseconds). Then, using biophysical models neglecting exchange, we estimate extracellular, neuronal and astrocytic lactate fractions compatible with the ANLS hypothesis.
title Probing lactate exchange and compartmentation in Gray Matter via time-dependent diffusion-weighted MRS
topic Medical Physics
url https://arxiv.org/abs/2412.16014