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Extracellular Mitochondria in Cerebrospinal Fluid and Neurological Recovery After Subarachnoid Hemorrhage.

ABSTRACT: Recent studies suggest that extracellular mitochondria may be involved in the pathophysiology of stroke. In this study, we assessed the functional relevance of endogenous extracellular mitochondria in cerebrospinal fluid (CSF) in rats and humans after subarachnoid hemorrhage (SAH).A standard rat model of SAH was used, where an intraluminal suture was used to perforate a cerebral artery, thus leading to blood extravasation into subarachnoid space. At 24 and 72 hours after SAH, neurological outcomes were measured, and the standard JC1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-benzimidazolylcarbocyanineiodide) assay was used to quantify mitochondrial membrane potentials in the CSF. To further support the rat model experiments, CSF samples were obtained from 41 patients with SAH and 27 control subjects. Mitochondrial membrane potentials were measured with the JC1 assay, and correlations with clinical outcomes were assessed at 3 months.In the standard rat model of SAH, extracellular mitochondria was detected in CSF at 24 and 72 hours after injury. JC1 assays demonstrated that mitochondrial membrane potentials in CSF were decreased after SAH compared with sham-operated controls. In human CSF samples, extracellular mitochondria were also detected, and JC1 levels were also reduced after SAH. Furthermore, higher mitochondrial membrane potentials in the CSF were correlated with good clinical recovery at 3 months after SAH onset.This proof-of-concept study suggests that extracellular mitochondria may provide a biomarker-like glimpse into brain integrity and recovery after injury.

SUBMITTER: Chou SH

PROVIDER: S-EPMC5526718 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Extracellular Mitochondria in Cerebrospinal Fluid and Neurological Recovery After Subarachnoid Hemorrhage.

Chou Sherry H-Y SH Lan Jing J Esposito Elga E Ning MingMing M Balaj Leonora L Ji Xunming X Lo Eng H EH Hayakawa Kazuhide K

Stroke 20170629 8

<h4>Background and purpose</h4>Recent studies suggest that extracellular mitochondria may be involved in the pathophysiology of stroke. In this study, we assessed the functional relevance of endogenous extracellular mitochondria in cerebrospinal fluid (CSF) in rats and humans after subarachnoid hemorrhage (SAH).<h4>Methods</h4>A standard rat model of SAH was used, where an intraluminal suture was used to perforate a cerebral artery, thus leading to blood extravasation into subarachnoid space. At ...[more]

PMID: 28663512

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Project description:Biological aging may occur at different rates than chronological aging due to genetic, social, and environmental factors. DNA methylation (DNAm) age is thought to be a reliable measure of accelerated biological aging which has been linked to an array of poor health outcomes. Given the importance of chronological age in recovery following aneurysmal subarachnoid hemorrhage (aSAH), a type of stroke, DNAm age may also be an important biomarker of outcomes, further improving predictive models. Cerebrospinal fluid (CSF) is a unique tissue representing the local central nervous system environment post-aSAH. However, the validity of CSF DNAm age is unknown, and it is unclear which epigenetic clock is ideal to compute CSF DNAm age, particularly given changes in cell type heterogeneity (CTH) during the acute recovery period. Further, the stability of DNAm age post-aSAH, specifically, has not been examined and may improve our understanding of patient recovery post-aSAH. Therefore, the purpose of this study was to characterize CSF DNAm age over 14 days post-aSAH using four epigenetic clocks. Genome-wide DNAm data were available for two tissues: (1) CSF for N = 273 participants with serial sampling over 14 days post-aSAH (N = 850 samples) and (2) blood for a subset of n = 72 participants at one time point post-aSAH. DNAm age was calculated using the Horvath, Hannum, Levine, and "Improved Precision" (Zhang) epigenetic clocks. "Age acceleration" was computed as the residuals of DNAm age regressed on chronological age both with and without correcting for CTH. Using scatterplots, Pearson correlations, and group-based trajectory analysis, we examined the relationships between CSF DNAm age and chronological age, the concordance between DNAm ages calculated from CSF versus blood, and the stability (i.e., trajectories) of CSF DNAm age acceleration over time during recovery from aSAH. We observed moderate to strong correlations between CSF DNAm age and chronological age (R = 0.66 [Levine] to R = 0.97 [Zhang]), moderate to strong correlations between DNAm age in CSF versus blood (R = 0.69 [Levine] to R = 0.98 [Zhang]), and stable CSF age acceleration trajectories over 14 days post-aSAH in the Horvath and Zhang clocks (unadjusted for CTH), as well as the Hannum clock (adjusted for CTH). CSF DNAm age was generally stable post-aSAH. Although correlated, CSF DNAm age differs from blood DNAm age in the Horvath, Hannum, and Levine clocks, but not in the Zhang clock. Taken together, our results suggest that, of the clocks examined here, the Zhang clock is the most robust to CTH and is recommended for use in complex tissues such as CSF.

Project description:Object: The aim of this study was to investigate metabolite levels in cerebrospinal fluid (CSF) in their time-dependent course after aneurysmal subarachnoid hemorrhage (aSAH) comparing them to patients harboring unruptured intracranial aneurysms. Methods: Eighty CSF samples of 16 patients were analyzed. The study population included patients undergoing endovascular/microsurgical treatment of ruptured intracranial aneurysms (n = 8), which were assessed for 9 days after aSAH. Control samples were collected from the basal cisterns in elective aneurysm surgery (n = 8). The CSF samples were consecutively collected with extraventricular drain (EVD) placement/intraoperatively, 6 h later, and daily thereafter (day 1-9). The endogenous metabolites were analyzed with a targeted quantitative and quality controlled metabolomics approach using the AbsoluteIDQ®p180Kit. Differences inbetween timepoints and compared to the control group were evaluated. Results: Numerous alterations of amino acid (AA) levels were detected within the first hours after bleeding. The highest mean concentrations occurred 1 week after aSAH. AA levels were continuously increasing over time starting 6 h after aSAH. Taurine concentration was highest briefly after aSAH starting to decrease already after 6 h (vs. day 1-9, p = 0.02). The levels of sphingomyelins/ phosphatidylcholines/ lysophosphatidylcholines/mono-unsaturated fatty acid chain were highly elevated on day 0 (compared to other timepoints or controls, p < 0.01) and decreased over the next several days to concentrations comparable to the control group. Carnitine concentrations were decreased after SAH (vs. day 7, p < 0.01), while they recovered within the next day. The Fischer ratio of branched-chain AA to aromatic AA was lowest immediately after SAH and increased in 7 days (p < 0.001). Conclusion: AA levels in CSF increased overtime and often differ from patients without SAH. There was a peak concentration of structural AA within the first 6 h after aneurysm treatment. Time-dependent alterations of CSF metabolites and compounds may elucidate pathophysiological processes after aSAH, providing potential predictors assessed non-invasively by routine lab testing.

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Dataset Information

Extracellular Mitochondria in Cerebrospinal Fluid and Neurological Recovery After Subarachnoid Hemorrhage.

Publications

Extracellular Mitochondria in Cerebrospinal Fluid and Neurological Recovery After Subarachnoid Hemorrhage.

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