Fluid preservation in brain banking: a review

Bibliographic Details
Title: Fluid preservation in brain banking: a review
Authors: Andrew McKenzie, Oge Nnadi, Kat D. Slagell, Emma L. Thorn, Kurt Farrell, John F. Crary
Source: Free Neuropathology, Vol 5 (2024)
Publisher Information: University of Münster / Open Journals System, 2024.
Publication Year: 2024
Collection: LCC:Neurosciences. Biological psychiatry. Neuropsychiatry
Subject Terms: Biobanking, Postmortem brain, Fluid preservation, Formaldehyde, Overfixation, Storage artifact, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
More Details: Fluid preservation is nearly universally used in brain banking to store fixed tissue specimens for future research applications. However, the effects of long-term immersion on neural circuitry and biomolecules are not well characterized. As a result, there is a need to synthesize studies investigating fluid preservation of brain tissue. We searched PubMed and other databases to identify studies measuring the effects of fluid preservation in nervous system tissue. We categorized studies based on the fluid preservative used: formaldehyde solutions, buffer solutions, alcohol solutions, storage after tissue clearing, and cryoprotectant solutions. We identified 91 studies containing 197 independent observations of the effects of long-term storage on cellular morphology. Most studies did not report any significant alterations due to long-term storage. When present, the most frequent alteration was decreased antigenicity, commonly attributed to progressive crosslinking by aldehydes that renders biomolecules increasingly inaccessible over time. To build a mechanistic understanding, we discuss biochemical aspects of long-term fluid preservation. A subset of lipids appears to be chemical altered or extracted over time due to incomplete retention in the crosslinked gel. Alternative storage fluids mitigate the problem of antigen masking but have not been extensively characterized and may have other downsides. We also compare fluid preservation to cryopreservation, paraffin embedding, and resin embedding. Overall, existing evidence suggests that fluid preservation provides maintenance of neural architecture for decades, including precise structural details. However, to avoid the well-established problem of overfixation caused by storage in high concentration formaldehyde solutions, fluid preservation procedures can use an initial fixation step followed by an alternative long-term storage fluid. Further research is warranted on optimizing protocols and characterizing the generalizability of the storage artifacts that have been identified.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2699-4445
Relation: https://www.uni-muenster.de/Ejournals/index.php/fnp/article/view/5373; https://doaj.org/toc/2699-4445
DOI: 10.17879/freeneuropathology-2024-5373
Access URL: https://doaj.org/article/9b23608f44054914bf11f55f38374b32
Accession Number: edsdoj.9b23608f44054914bf11f55f38374b32
Database: Directory of Open Access Journals
More Details
ISSN:26994445
DOI:10.17879/freeneuropathology-2024-5373
Published in:Free Neuropathology
Language:English