Postmortem Cerebrospinal Fluid Research Articles

Bank vole prion protein extends the use of RT-QuIC assays to detect prions in a range of inherited prion diseases

The cerebrospinal fluid (CSF) real-time quaking-induced conversion assay (RT-QuIC) is an ultrasensitive prion amyloid seeding assay for diagnosis of sporadic Creutzfeldt–Jakob disease (CJD) but several prion strains remain unexplored or resistant to conversion with commonly used recombinant prion protein (rPrP) substrates. Here, bank vole (BV) rPrP was used to study seeding by a wide range of archived post-mortem human CSF samples from cases of sporadic, acquired and various inherited prion diseases in high throughput 384-well format. BV rPrP substrate yielded positive reactions in 70/79 cases of sporadic CJD [Sensitivity 88.6% (95% CI 79.5–94.7%)], 1/2 variant CJD samples, and 9/20 samples from various inherited prion diseases; 5/57 non-prion disease control CSFs had positive reactions, yielding an overall specificity of 91.2% (95% CI 80.1–97.1%). Despite limitations of using post-mortem samples and our results’ discrepancy with other studies, we demonstrated for the first time that BV rPrP is susceptible to conversion by human CSF samples containing certain prion strains not previously responsive in conventional rPrPs, thus justifying further optimisation for wider diagnostic and prognostic use.

Decreased pH in the aging brain and Alzheimer's disease

Using publicly available data sets, we compared pH in the human brain and the cerebrospinal fluid (CSF) of postmortem control and Alzheimer's disease cases. We further investigated the effects of long-term acidosis in vivo in the APP-PS1 mouse model of Alzheimer's disease. We finally examined in vitro whether low pH exposure could modulate the release of proinflammatory cytokines and the uptake of amyloid beta by microglia. In the human brain, pH decreased with aging. Similarly, we observed a reduction of pH in the brain of C57BL/6 mice with age. In addition, independent database analyses revealed that postmortem brain and CSF pH is further reduced in Alzheimer's disease cases compared with controls. Moreover, in vivo experiments showed that low pH CSF infusion increased amyloid beta plaque load in APP-PS1 mice. We further observed that mild acidosis reduced the amyloid beta 42–induced release of tumor necrosis factor–alpha by microglia and their capacity to uptake this peptide. Brain acidosis is associated with aging and might affect pathophysiological processes such as amyloid beta aggregation or inflammation in Alzheimer's disease.

Semiautomated robotic, CT-guided needle placement for postmortem CSF sampling – a Novel application of the Virtobot

The sampling of cerebrospinal fluid (CSF) for chemical analysis is usually performed by a freehand lumbar puncture in a routine clinical procedure, while the suboccipital region is used for postmortem examinations. We introduce a new application for a semiautomated robotic, computed tomography (CT)-guided needle placement for postmortem lumbar and suboccipital CSF sampling. Postmortem computed tomography (PMCT) imaging was performed, and the data were sent to a custom-made Virtopsy Control Center and Virtopsy Planning and Navigation Station. Needle trajectories were planned for both suboccipital and lumbar approaches. Coaxial introducer needles were fully inserted automatically by the robotic system. PMCT was repeated to verify correct placement of the needles. Subsequently, CSF samples were taken using a syringe. By using this new application, the puncture of the spinal canal and cerebellomedullary cistern could be accurately performed to within a millimeter. Thus, failure of puncture and iatrogenic injury of the medulla oblongata may be prevented, and the risk of infection is significantly reduced. An early analysis of the CSF sample allows for a risk assessment in regard to the subsequent autopsy. Our application allows for minimally invasive, fast, efficient and safe CSF sampling prior to autopsy, enabling an analysis for metabolic imbalance, infection, etc.

Metabolomics in postmortem cerebrospinal fluid diagnostics: a state-of-the-art method to interpret central nervous system\u2013related pathological processes

In the last few years, quantitative analysis of metabolites in body fluids using LC/MS has become an established method in laboratory medicine and toxicology. By preparing metabolite profiles in biological specimens, we are able to understand pathophysiological mechanisms at the biochemical and thus the functional level. An innovative investigative method, which has not yet been used widely in the forensic context, is to use the clinical application of metabolomics. In a metabolomic analysis of 41 samples of postmortem cerebrospinal fluid (CSF) samples divided into cohorts of four different causes of death, namely, cardiovascular fatalities, isoIated torso trauma, traumatic brain injury, and multi-organ failure, we were able to identify relevant differences in the metabolite profile between these individual groups. According to this preliminary assessment, we assume that information on biochemical processes is not gained by differences in the concentration of individual metabolites in CSF, but by a combination of differently distributed metabolites forming the perspective of a new generation of biomarkers for diagnosing (fatal) TBI and associated neuropathological changes in the CNS using CSF samples.

Combining Postmortem Cerebrospinal Fluid Biochemistry With Lung-to-Body Ratio to Aid the Diagnosis of Salt Water Drowning.

Diagnosing drowning as a cause of death can pose many challenges for the forensic pathologist and a number of ancillary tests have been proposed to assist in the diagnosis, whether the body was in salt water or fresh water. Although elevated vitreous humor sodium and chloride is a reliable marker, its limitation to prolonged immersion has resulted in the recent investigation of cerebrospinal fluid (CSF) sodium and chloride as alternative matrix in cases of longer or unknown immersion times. This study investigated postmortem CSF from lumbar puncture (CSF_L_Na_Cl) and ventricular aspiration (CSF_Vent_Na_Cl), as well as lung/body (LB) ratio in the diagnosis of salt water drowning and performed comparison and combination testing of methods to improve diagnostic accuracy of the drowning diagnosis. This study found that CSF_L_Na_Cl was the most accurate method (89%) in the given cohort, but that CSF_Vent_Na_Cl and LB combined was the second most accurate method (83%), exceeding CSF_Vent_Na_Cl (77%) and LB (81%) used alone. These findings are useful for stratifying and prioritizing postmortem samples in the investigation of salt water drowning and also have significance for future studies using this methodology to combine and compare the accuracy of different investigations.

Disease-Specific Changes in Reelin Protein and mRNA in Neurodegenerative Diseases.

Reelin is an extracellular glycoprotein that modulates neuronal function and synaptic plasticity in the adult brain. Decreased levels of Reelin activity have been postulated as a key factor during neurodegeneration in Alzheimer’s disease (AD) and in aging. Thus, changes in levels of full-length Reelin and Reelin fragments have been revealed in cerebrospinal fluid (CSF) and in post-mortem brains samples of AD patients with respect to non-AD patients. However, conflicting studies have reported decreased or unchanged levels of full-length Reelin in AD patients compared to control (nND) cases in post-mortem brains and CSF samples. In addition, a compelling analysis of Reelin levels in neurodegenerative diseases other than AD is missing. In this study, we analyzed brain levels of RELN mRNA and Reelin protein in post-mortem frontal cortex samples from different sporadic AD stages, Parkinson’s disease with dementia (PDD), and Creutzfeldt-Jakob disease (sCJD), obtained from five different Biobanks. In addition, we measured Reelin protein levels in CSF samples of patients with mild cognitive impairment (MCI), dementia, or sCJD diagnosis and a group of neurologically healthy cases. The results indicate an increase in RELN mRNA in the frontal cortex of advanced stages of AD and in sCJD(I) compared to controls. This was not observed in PDD and early AD stages. However, Reelin protein levels in frontal cortex samples were unchanged between nND and advanced AD stages and PDD. Nevertheless, they decreased in the CSF of patients with dementia in comparison to those not suffering with dementia and patients with MCI. With respect to sCJD, there was a tendency to increase in brain samples in comparison to nND and to decrease in the CSF with respect to nND. In conclusion, Reelin levels in CSF cannot be considered as a diagnostic biomarker for AD or PDD. However, we feel that the CSF Reelin changes observed between MCI, patients with dementia, and sCJD might be helpful in generating a biomarker signature in prodromal studies of unidentified dementia and sCJD.

Interleukin-9 regulates macrophage activation in the progressive multiple sclerosis brain

BackgroundMultiple sclerosis (MS) is an immune-mediated, chronic inflammatory, and demyelinating disease of the central nervous system (CNS). Several cytokines are thought to be involved in the regulation of MS pathogenesis. We recently identified interleukin (IL)-9 as a cytokine reducing inflammation and protecting from neurodegeneration in relapsing–remitting MS patients. However, the expression of IL-9 in CNS, and the mechanisms underlying the effect of IL-9 on CNS infiltrating immune cells have never been investigated.MethodsTo address this question, we first analyzed the expression levels of IL-9 in post-mortem cerebrospinal fluid of MS patients and the in situ expression of IL-9 in post-mortem MS brain samples by immunohistochemistry. A complementary investigation focused on identifying which immune cells express IL-9 receptor (IL-9R) by flow cytometry, western blot, and immunohistochemistry. Finally, we explored the effect of IL-9 on IL-9-responsive cells, analyzing the induced signaling pathways and functional properties.ResultsWe found that macrophages, microglia, and CD4 T lymphocytes were the cells expressing the highest levels of IL-9 in the MS brain. Of the immune cells circulating in the blood, monocytes/macrophages were the most responsive to IL-9. We validated the expression of IL-9R by macrophages/microglia in post-mortem brain sections of MS patients. IL-9 induced activation of signal transducer and activator of transcription (STAT)1, STAT3, and STAT5 and reduced the expression of activation markers, such as CD45, CD14, CD68, and CD11b in inflammatory macrophages stimulated in vitro with lipopolysaccharide and interferon (IFN)-γ. Similarly, in situ the number of activated CD68+ macrophages was significantly reduced in areas with high levels of IL-9. Moreover, in the same conditions, IL-9 increased the secretion of the anti-inflammatory cytokine, transforming growth factor (TGF)-β.ConclusionsThese results reveal a new cytokine expressed in the CNS, with a role in the context of MS. We have demonstrated that IL-9 and its receptor are both expressed in CNS. Moreover, we found that IL-9 decreases the activation state and promotes the anti-inflammatory properties of human macrophages. This mechanism may contribute to the beneficial effects of IL-9 that are observed in MS, and may be therapeutically potentiated by modulating IL-9 expression in MS.

Comprehensive quantification of purine and pyrimidine metabolism in Alzheimer's disease postmortem cerebrospinal fluid by LC-MS/MS with metal-free column.

The metabolome presence of nucleobases, nucleosides, nucleotides and related phosphorylated metabolites has been examined for Alzheimer's disease (AD). Although reversed-phase liquid chromatography tandem mass spectrometry (LC-MS/MS) has been used for the determination of these analytes, they were limited in chromatographic signal intensity and reproducibility owing to significant peak tailing caused by complexing with metallic cations and phosphate groups. In this work, we applied LC-MS/MS analysis with a metal-free column for comprehensive quantification of 40 analytes regarding to purine and pyrimidine metabolism in postmortem cerebrospinal fluid (pCSF) from AD patients. For the analytical column, an InertSustain AQ-C18 metal-free PEEK column was used. MS detection was by electrospray positive ionization. The metal-free column allowed for sharp peak detection of highly polar metabolites within a running time of 17 min. In validation, the limits of detection (LOD), the limit of quantitation (LOQ) and recovery value using a pooled pCSF sample are 1-500 nM, 0.5-250 nM and a range of 53.1-144.0% (RSD ranged from 0.4 to 19.6%). The developed LC-MS/MS method utilizing a metal-free column provides an accurate quantification of some metabolites regarding purine and pyrimidine metabolism in pCSF samples obtained from AD patients.

Postmortem serotonin level in cerebrospinal fluid as a marker of the manner of death

Background/Aim. Serotonin [5-hydroxytriptanine (5-HT)], as a neurotransmitter in the central nervous system, is included in the regulation of autonomic and cognitive functions, sensory processing, motor activity, emotions, mood, and almost every kind of behavior. In forensic investigations of death, 5-HT has been studied in different body fluids, regarding the cause of death, particularly in suicides and drug abuse or as a marker of an acute stress response. The aim of this study was to establish 5-HT levels in cerebrospinal fluid (CSF) as a marker of its central activity during fatal event in deaths different in manner, particularly in cases where the victims were aware of the stressful event. Methods. Study sample consisted of 81 postmortem CSF obtained during autopsy. Concentrations of the 5-HT were established regarding natural versus violent (accidents, homicides and suicides) deaths. After preparation, samples were analyzed through the liquid chromatography-tandem mass spectrometry method. Results. Violent deaths had significantly higher 5-HT levels (U = 519.000; p < 0.05). Differences were found in mean values among different causes of death (higher in blunt injury, stabbing and intoxication, while lower in cardiac deaths and hypothermia) but without statistical significance. 5-HT levels significantly differed among age groups (?2 = 13.354; p = 0.001), with the tendency to decrease with age. No differences in 5-HT levels were observed regarding gender, length of agony period, and awareness of impending lethal outcome. The values tended to increase with postmortem interval albeit without significant differences. Conclusion. Serotonin could be a useful postmortem biochemical marker to distinguish natural and violent death, regardless of individual variability in concentrations.

Risk of developing cerebral β-amyloid plaques with posttranslational modification among HIV-infected adults.

Evidence of accelerated brain aging among HIV-infected adults argues for the increased risk of developing cerebral β-amyloid (Aβ) plaques. We compared the frequency of Aβ plaque-bearing cases in our HIV cohort with that in a general cohort reported by Braak et al. We explored posttranslationally modified Aβ forms (N3pE, E22P, phospho-Ser8) in plaques and E22P-Aβ in the postmortem cerebrospinal fluid (CSF) in the HIV cohort. Clinicopathological study of HIV-infected adults. To assess frontal Aβ plaque deposition, we conducted immunohistochemistry for generic Aβ (4G8) and three modified Aβ forms. We determined CSF E22P-Aβ levels by ELISA. We found 4G8-Aβ plaques in 29% of 279 HIV-infected cases. Within the age range of 31-70 years, the frequency of 4G8-Aβ plaque-bearing cases was higher in our HIV cohort (n = 273) compared with the general cohort (n = 1110) overall (29.3 vs. 25.8%) and across four age groups by decade (odds ratio 2.35, P < 0.0001). In HIV-infected cases with (n = 37) and without (n = 12) 4G8-Aβ plaques, modified Aβ forms occurred in order: N3pE, E22P, and phospho-Ser8. In CSF assays of HIV-infected cases with (n = 27; 17 focal, 10 widespread) and without (n = 11) 4G8-Aβ plaques, the median E22P-Aβ/Aβ40 ratio was higher among cases with widespread plaques than in cases with focal or absent plaques (P = 0.047). Our findings suggest HIV-infected adults are at increased risk of developing cerebral Aβ plaques. The occurrence of modified Aβ forms in order suggests the progression stages of Aβ plaque deposition. The potential for E22P-Aβ as a CSF biomarker of cerebral Aβ plaques should be investigated.

4-Repeat tau seeds and templating subtypes as brain and CSF biomarkers of frontotemporal lobar degeneration.

To address the need for more meaningful biomarkers of tauopathies, we have developed an ultrasensitive tau seed amplification assay (4R RT-QuIC) for the 4-repeat (4R) tau aggregates of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and other diseases with 4R tauopathy. The assay detected seeds in 106-109-fold dilutions of 4R tauopathy brain tissue but was orders of magnitude less responsive to brain with other types of tauopathy, such as from Alzheimer's disease cases. The analytical sensitivity for synthetic 4R tau fibrils was ~ 50fM or 2fg/sample. A novel dimension of this tau RT-QuIC testing was the identification of three disease-associated classes of 4R tau seeds; these classes were revealed by conformational variations in the in vitro amplified tau fibrils as detected by thioflavin T fluorescence amplitudes and FTIR spectroscopy. Tau seeds were detected in postmortem cerebrospinal fluid (CSF) from all neuropathologically confirmed PSP and CBD cases but not in controls. CSF from living subjects had weaker seeding activities; however, mean assay responses for cases clinically diagnosed as PSP and CBD/corticobasal syndrome were significantly higher than those from control cases. Altogether, 4R RT-QuIC provides a practical cell-free method of detecting and subtyping pathologic 4R tau aggregates as biomarkers.

Elevation of Postmortem Cerebrospinal Fluid Sodium and Chloride Levels Is a Potential Adjunct Test in the Diagnosis of Salt Water Drowning.

Postmortem vitreous humor biochemistry is a useful test in the diagnosis of salt water drowning (SWD). A significant limitation of vitreous humor is the potential effect of prolonged immersion. A recent animal study and case report suggested that cerebrospinal fluid biochemistry may be an alternative to vitreous because it is more resistant to the effects of immersion, given its protected anatomical location. This study compared postmortem cerebrospinal fluid sodium and chloride (PMCSC) levels collected via ventricular aspiration (PMCSC_V) and via lumbar puncture (PMCSC_L) in 13 SWD and 31 nonimmersion deaths. It showed a significant elevation in PMCSC levels in SWD deaths for both PMCSC_V and PMCSC_L (P < 0.05). The areas under the curve on the receiver operating characteristic curves for PMCSC_V and PMCSC_L were 0.73 and 0.83, respectively. The optimal cutoff for PMCSC_V was 216 mmol/L (sensitivity, 0.60; specificity, 0.72; likelihood ratio, 1.80; positive predictive value, 0.45) and for PMCSC_L was 241 mmol/L (sensitivity, 0.78; specificity, 0.73; likelihood ratio, 2.89; positive predictive value, 0.46). This study supports PMCSC levels as another biochemical test that can potentially aid in the diagnosis of SWD, particularly in cases where vitreous humor samples are unavailable or uninterpretable.

Post-mortem biochemistry differences between vitreous humour and cerebrospinal fluid

ABSTRACT Cerebrospinal fluid (CSF) and vitreous humour (VH) can be biochemically analysed post-mortem. CSF can be aspirated from the ventricular system (VA) and from lumbar puncture (LP), whereas, VH is aspirated from the orbits. This study compared the biochemical constituents between CSF and VH in 20 post-mortem subjects as well as the effect post-mortem interval and subject age have on these variables. VH samples had significantly higher sodium (Na) and chloride (Cl) and lower magnesium (Mg), potassium (K), urea (Ur) and creatinine (Cr) compared with CSF samples. No statistically significant difference was demonstrated with beta-hydroxybutyrate (BHB) and glucose levels in both VH and both CSF samples. Interestingly, some of the differences in the biochemical analysis correlated with age, but none with post-mortem interval. In addition to sampling and pre-analytical sample processing differences, there may also be ante- and post-mortem factors explaining these observations. This study suggests that post-mortem CSF and VH are biochemically different and reference ranges for VH are not recommended for use in CSF samples.

Post-mortem cerebrospinal fluid diagnostics: cytology and immunocytochemistry method suitable for routine use to interpret pathological processes in the central nervous system.

Due to its protected anatomical location, cerebrospinal fluid (CSF) is a very stable fluid which undergoes comparatively little change in the early post-mortem phase. While many immunohistochemical markers already established for clinical diagnostic issues in tissue samples obtained by biopsy could meanwhile be translated also to post-mortem tissue, no systematic immunocytochemical investigations have generally been conducted on post-mortem body fluids and for CSF specifically, have not been established at all. CSF as the fluid directly surrounding the brain should also be examined to allow a more detailed characterization of processes in the central nervous system. Comparing traumatized tissue and CSF can complete forensic assessment and complement neuropathological evaluation.

Differences in Sampling Site on Postmortem Cerebrospinal Fluid Biochemistry: A Preliminary Study.

Cerebrospinal fluid (CSF) is often analyzed at postmortem. The presented preliminary study compared postmortem CSF samples for biochemical analysis from the subarachnoid space around the spinal cord and ventricular space of the brain. This study compared 15 paired CSF samples in which the CSF from the subarachnoid space via lumbar puncture had higher sodium and chloride levels and lower magnesium and potassium levels than CSF from the ventricles. The differences correlated significantly with the deceased's age and had a similar trend with postmortem interval. This study suggests that CSF from different collection sites has different electrolyte concentrations, which are age and possibly postmortem interval dependent. When collecting CSF, the pathologist should document the collection site, age, and postmortem interval, and the mixing of CSF samples from different sites should be avoided. Further studies are warranted to clarify other possible reasons to explain the observed differences.

Widely targeted metabolomics of Alzheimer's disease postmortem cerebrospinal fluid based on 9-fluorenylmethyl chloroformate derivatized ultra-high performance liquid chromatography tandem mass spectrometry

Confirmed biomarkers of postmortem cerebrospinal fluid (pCSF) are used to differentiate between Alzheimer's disease (AD) patients and healthy seniors with high diagnostic accuracy. However, the extent to which the performance of specific metabolic profiling facilitates reliable estimations of the concentrations of the different pCSF biomarkers and their ratios remains unclear. The interpretation of the lower levels of molecules of metabolic profiling and their concentration ratios in pCSF related to brain disorders could facilitate an unchallenging detection of peripheral biomarkers of AD stages and other dementia types. In this study, we proposed the use of widely targeted metabolomics for pCSF metabolic profiling using 9-fluorenylmethyl chloroformate- (FMOC) derivatized ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to evaluate the diversity of 97 amine-mediated metabolic patterns and pathways from confirmed diagnosis based on AD brain pathology. Our results identified the metabolites that contributed toward and mutually influenced the principal component analysis plot with integrated analytes. Furthermore, the AD group showed a significant variation in several analyte concentration levels compared to those of control subjects. These trends of the concentration levels expressed by the amine metabolic pathways indicated the decreased activity of polyamine and tryptophan-kynurenine (Trp-Kyn) metabolisms. Moreover, increased metabolites such as methionine sulfoxide, 3-methoxy-anthranilate, cadaverine, guanine, and histamine were observed by widely targeted metabolomics of pCSF from the AD subjects. According to their metabolic pathway analysis using FMOC-derivatized UHPLC-MS/MS assay, we supposed that the involvement of polyamine and Trp-Kyn metabolisms was observed in the pCSF samples.

25.3 OLIGODENDROCYTES MEDIATE ENERGY METABOLISM ALTERATIONS IN SCHIZOPHRENIA: A PROTEOMIC STUDY

BackgroundWhile comparing the proteomes and subproteomes of 8 post-mortem brain regions and cerebrospinal fluid from schizophrenia patients to controls, we consistently observed alterations in energy metabolism, cell growth and maintenance, synaptic function, and myelinization processes. Considering the nature of these analyses, it was not possible to reveal which particular cell types display such alterations. This is essential information given increasing evidence of glia cells as pivotal players in schizophrenia. With this in mind, we analyzed the proteomes and phosphoproteomes of cultured astrocytes, oligodendrocytes and neurons treated with MK-801, a NMDA-receptor antagonist which impairs glutamatergic transmission as postulated in schizophrenia. We also analyzed biochemical pathways modulated by typical and atypical antipsychotics in human oligodendrocytes. Results led us to employ induced pluripotent stem cell-derived cerebral organoids to deepen our understanding of the data. The central aim of this study is to depict which cell type(s) present proteome changes similarly to those we found in our earlier analysis of human brain tissue as well as identify key pathways for an effective antipsychotic response.MethodsCell line cultures (astrocytes, oligodendrocytes and neurons) were treated with MK-801 and oligodendrocytes were also treated with a range of typical and atypical antipsychotics. In addition, human embryonic stem cells reprogramed from schizophrenia patients and controls fibroblasts were cultured in mTeSR1 media on Matrigel coated surface and then differentiated into cerebral organoids. All pre-clinical models here employed were submitted to state-of-the art large-scale proteomic analyses. In silico systems biology was employed to identify key pathways in the studied processes.ResultsMK-801-treated astrocytes, and especially MK-801-treated oligodendrocytes displayed several proteins differentially expressed which overlapped with previous findings of schizophrenia human brains. On the other hand, MK801-treated neurons displayed very few differences in their proteome, an overlap with previous findings in human brain tissue below 10%. More interestingly, the dysregulation of glycolytic enzymes in MK801-treated oligodendrocytes are very similar to our observations in schizophrenia brain tissue, corroborating with recent findings about of the importance of oligodendrocytes in the energy status of the brain. In oligodendrocytes, antipsychotics displayed differences in translational machinery and eIF2 signaling. Findings on cerebral organoids also showed overlaps with previous postmortem data, mainly on synaptic proteins and specially energy metabolism-associated pathways.DiscussionThese findings hold potential for the investigation of developmental and evolutionary features of schizophrenia brains and provides targets to be drug-screened as well as leads to the schizophrenia pathobiology.

Cerebrospinal fluid Lyme multiplex assay results are not diagnostic in horses with neuroborreliosis.

BackgroundThe accuracy of the Lyme multiplex assay for the diagnosis of neuroborreliosis in horses is unknown.Hypothesis/ObjectivesTo describe Lyme multiplex results in horses with a postmortem diagnosis of neuroborreliosis. The hypothesis was that paired serum and cerebrospinal fluid (CSF) results and a CSF : serum ratio would allow differentiation of horses with neuroborreliosis from those with other neurologic diseases.AnimalsNinety horses that had neurologic examinations, serum and CSF Lyme multiplex analyses, and postmortem examination of the nervous system performed.MethodsRetrospective study. Data collected included signalment, ante‐ and postmortem diagnoses, and serum and CSF Lyme multiplex results. The CSF : serum ratio was calculated by dividing CSF median fluorescent intensity (MFI) by serum MFI for each result.ResultsTen horses had a final diagnosis of neuroborreliosis, 70 were diagnosed with other neurologic diseases, and 10 had no neurologic disease. Not all horses with neuroborreliosis had positive results: 4/10 had at least 1 positive serum result, 5/10 had at least 1 positive CSF result, and 3/10 had at least 1 CSF result 4‐fold higher than the corresponding serum result. Results were similar for the 70 horses with other neurologic diseases: 53% had at least 1 positive serum result, 50% had at least 1 positive CSF result, and 16% had at least 1 CSF result 4‐fold higher than the corresponding serum result.Conclusions and Clinical ImportancePositive Lyme multiplex results were common in horses with neurologic diseases and did not adequately differentiate horses with neuroborreliosis from horses with other disorders.

Calmodulin-like skin protein is downregulated in human cerebrospinal fluids of Alzheimer's disease patients with apolipoprotein E4; a pilot study using postmortem samples

AbstractObjective: Calmodulin-like skin protein (CLSP) is a secreted peptide that inhibits neuronal cell death, linked to Alzheimer’s disease (AD), by binding to the heterotrimeric humanin receptor and activating an intracellular survival pathway. CLSP is only expressed in skin keratinocytes and related epithelial cells, circulates in the blood stream, and passes the blood–cerebrospinal fluid (CSF) barrier. In the current study, we addressed the issues as to whether CLSP functions in the central nervous system and whether the concentration of CLSP is reduced in the CSFs of AD patients.Methods: Mice were intraperitoneally injected with 5 nmol of recombinant human CLSP. At 1h after the injection, the mice were sacrificed for the analysis of the existence of human CLSP in blood and interstitial fluid (ISF)-containing brain samples. Using postmortem CSF samples, we next determined the concentrations of CLSP in CSFs of human AD and control cases.Results: Intraperitoneally administered recombinant human CLSP ci...

CCL11 is increased in the CNS in chronic traumatic encephalopathy but not in Alzheimer's disease.

CCL11, a protein previously associated with age-associated cognitive decline, is observed to be increased in the brain and cerebrospinal fluid (CSF) in chronic traumatic encephalopathy (CTE) compared to Alzheimer’s disease (AD). Using a cohort of 23 deceased American football players with neuropathologically verified CTE, 50 subjects with neuropathologically diagnosed AD, and 18 non-athlete controls, CCL11 was measured with ELISA in the dorsolateral frontal cortex (DLFC) and CSF. CCL11 levels were significantly increased in the DLFC in subjects with CTE (fold change = 1.234, p < 0.050) compared to non-athlete controls and AD subjects with out a history of head trauma. This increase was also seen to correlate with years of exposure to American football (β = 0.426, p = 0.048) independent of age (β = -0.046, p = 0.824). Preliminary analyses of a subset of subjects with available post-mortem CSF showed a trend for increased CCL11 among individuals with CTE (p = 0.069) mirroring the increase in the DLFC. Furthermore, an association between CSF CCL11 levels and the number of years exposed to football (β = 0.685, p = 0.040) was observed independent of age (β = -0.103, p = 0.716). Finally, a receiver operating characteristic (ROC) curve analysis demonstrated CSF CCL11 accurately distinguished CTE subjects from non-athlete controls and AD subjects (AUC = 0.839, 95% CI 0.62–1.058, p = 0.028). Overall, the current findings provide preliminary evidence that CCL11 may be a novel target for future CTE biomarker studies.