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Singh G, van Laarhoven A, Adams R, Reid TD, Combrinck J, van Dorp S, Riou C, Thango N, Enslin J, Kruger S, Figaji AA, Rohlwink UK. The influence of fixation and cryopreservation of cerebrospinal fluid on antigen expression and cell percentages by flow cytometric analysis. Sci Rep 2024; 14:2463. [PMID: 38291295 PMCID: PMC10827736 DOI: 10.1038/s41598-024-52669-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/22/2024] [Indexed: 02/01/2024] Open
Abstract
The pauci-cellular nature of cerebrospinal (CSF), particularly ventricular CSF, and the rapid cell death following sampling, incumbers the use of flow cytometric analysis of these samples in the investigation of central nervous system (CNS) pathologies. Developing a method that allows long-term storage and batched analysis of CSF samples without compromising cell integrity is highly desirable in clinical research, given that CSF is often sampled after hours creating logistical difficulties for fresh processing. We examined percentages and relative proportion of peripheral and brain-derived immune cells in cryopreserved and transfix-treated CSF, compared to freshly processed CSF. Cell proportions were more comparable between Fresh and Cryopreserved CSF (mean of differences = 3.19), than between fresh and transfix-treated CSF (mean of differences = 14.82). No significant differences in cell percentages were observed in fresh versus cryopreserved CSF; however significantly lower cell percentages were observed in transfix-treated CSF compared to Fresh CSF [(CD11b++ (p = 0.01), CD4+ (p = 0.001), CD8+ (p = 0.007), NK cells (p = 0.04), as well as CD69+ activation marker (p = 0.001)]. Furthermore, loss of marker expression of various lymphocyte sub-populations were observed in transfix-treated CSF. Cryopreservation is a feasible option for long-term storage of ventricular CSF and allows accurate immunophenotyping of peripheral and brain-derived cell populations by flow cytometry.
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Affiliation(s)
- Gabriela Singh
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa.
| | - Arjan van Laarhoven
- Department of Internal Medicine and Radboud Center of Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rozanne Adams
- City of Cape Town, Becton Dickinson (BD) Biosciences, Western Cape, South Africa
| | - Timothy Dawson Reid
- South African Tuberculosis Vaccine Initiative (SATVI), Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Jill Combrinck
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Suzanne van Dorp
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catherine Riou
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Nqobile Thango
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Johannes Enslin
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Stefan Kruger
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Anthony Aaron Figaji
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Ursula Karin Rohlwink
- Division of Neurosurgery, Department of Surgery, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
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Takousis P, Devonshire AS, Redshaw N, von Baumgarten L, Whale AS, Jones GM, Fernandez-Gonzalez A, Martin J, Foy CA, Alexopoulos P, Huggett JF, Perneczky R. A standardised methodology for the extraction and quantification of cell-free DNA in cerebrospinal fluid and application to evaluation of Alzheimer's disease and brain cancers. N Biotechnol 2022; 72:97-106. [PMID: 36202346 DOI: 10.1016/j.nbt.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 09/23/2022] [Accepted: 10/01/2022] [Indexed: 11/27/2022]
Abstract
Cerebrospinal fluid (CSF) is a source of diagnostic biomarkers for a range of neurological conditions. Cell-free DNA (cfDNA) is detected in CSF and differences in the concentration of cell-free mitochondrial DNA have been reported in studies of neurodegenerative disorders including Alzheimer's disease (AD). However, the influence of pre-analytical steps has not been investigated for cfDNA in CSF and there is no standardised approach for quantification of total cfDNA (copies of nuclear genome or mitochondria-derived gene targets). In this study, the suitability of four extraction methods was evaluated: QIAamp Circulating Nucleic Acid (Qiagen), Quick-cfDNA Serum & Plasma (Zymo), NucleoSnap® DNA Plasma (Macherey-Nagel) and Plasma/Serum Circulating DNA Purification Mini (Norgen) kits, for cfDNA extraction from CSF of controls and AD dementia patients, utilising a spike-in control for extraction efficiency and fragment size. One of the optimal extraction methods was applied to a comparison of cfDNA concentrations in CSF from control subjects, AD dementia and primary and secondary brain tumour patients. Extraction efficiency based on spike-in recovery was similar in all three groups whilst both endogenous mitochondrial and nucleus-derived cfDNA was significantly higher in CSF from cancer patients compared to control and AD groups, which typically contained < 100 genome copies/mL. This study shows that it is feasible to measure low concentration nuclear and mitochondrial gene targets in CSF and that normalisation of extraction yield can help control pre-analytical variability influencing biomarker measurements.
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Affiliation(s)
- Petros Takousis
- Ageing Epidemiology (AGE) Research Unit, School of Public Health, Imperial College London, London, UK
| | - Alison S Devonshire
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK.
| | - Nicholas Redshaw
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK
| | - Louisa von Baumgarten
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany; Department of Neurosurgery, University Hospital, LMU Munich, Munich, Germany
| | - Alexandra S Whale
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK
| | - Gerwyn M Jones
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK
| | - Ana Fernandez-Gonzalez
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK
| | - Jan Martin
- Department of Anaesthesiology and Intensive Care Medicine, Technical University Munich, Munich, Germany
| | - Carole A Foy
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK
| | - Panagiotis Alexopoulos
- Department of Psychiatry, University of Patras, Rion Patras, Greece; Department of Psychiatry and Psychotherapy, Technical University Munich, Munich, Germany
| | - Jim F Huggett
- Molecular and Cell Biology Team, National Measurement Laboratory, LGC, Teddington, Middlesex, UK; School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Robert Perneczky
- Ageing Epidemiology (AGE) Research Unit, School of Public Health, Imperial College London, London, UK; Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
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