CSF Levels Research Articles

CSF proteomics analysis to investigate the pharmacodynamic response of the S2R modulator CT1812 in Alzheimer’s disease patients from the SPARC clinical trial

AbstractBackgroundCT1812 is an investigational therapeutic that can displace toxic amyloid‐beta oligomers from neuronal receptors and is currently in development for Alzheimer’s disease (AD). SPARC (COG0105; NCT03493282), was a randomized double‐blinded placebo‐controlled clinical trial designed to test the impact of the small molecule sigma‐2 receptor (S2R) modulator CT1812 on safety and synaptic density. Exploratory analyses included discovery proteomics for pharmacodynamic biomarker identification and to understand the impact of CT1812 on CSF proteins detected in mild to moderate AD patients.MethodUnbiased quantification, using tandem‐mass tag mass spectrometry (TMT‐MS), of proteomes from AD patients given the S2R modulator CT1812 or placebo (N=18) was performed on baseline and end of study CSF to test two doses (100 mg, 300 mg) of CT1812 given once daily for 6 months in participants with mild‐moderate AD. Individual CSF proteomes were compared to within‐study pooled AD and non‐demented control CSF reference standards from the Emory ADRC to benchmark protein levels in SPARC participant CSF at baseline and to assess treatment effects, via differential expression analysis (one‐way ANOVA; p<0.05) and pathway analyses.ResultA total of 2,760 CSF proteins were detected across all CSF samples. Strong correlations (r>|0.70|) between TMT‐MS values and clinically validated ELISAs for canonical AD biomarker levels (Tau, NFL) were observed across participants and timepoints, confirming previous findings of TMT‐MS as a quantitative method. Differential expression analyses identified 327 proteins altered (one‐way ANOVA; p<0.05) in CT1812 vs placebo CSF. From a curated list of previously published AD biomarkers representing distinct pathways, a subset of proteins were found to be significantly altered by treatment with CT1812 compared to placebo (p<0.05), and included some proteins known to be genetically linked to AD. Pathway analysis identified statistically significant pathways (p<0.05) altered by CT1812, including that tied to inflammation, amyloid biology, and synaptic function.ConclusionThis study enabled the identification of candidate pharmacodynamic biomarkers that may reflect target/pathway engagement or disease modification, and extends proteomics CSF learnings from previous clinical trials with CT1812. Overall, this data suggest CT1812 may impact key proteins and pathways in AD and provides additional support for CT1812 to be further evaluated as a promising therapy for AD.

Baseline blood amylin levels predict longitudinal cognitive decline in participants at risk for or with mild cognitive impairment and dementia

AbstractBackgroundAmylin is a systemic hormone that is co‐secreted with insulin from pancreatic β‐cells that co‐aggregates with parenchymal and vascular b‐amyloid in the CNS. Cross‐sectional data shows that higher CSF and blood amylin levels are associated with increased frequency of cognitive impairment and dementia. The present study sought to determine whether baseline blood amylin levels are associated with longitudinal cognitive decline.MethodWhole blood amylin levels were ascertained from 83 participants in a longitudinal cohort spanning the cognitive continuum from normal to MCI and dementia who were evaluated initially in 2017 and followed to present. Cognitive change data including MMSE, MoCA, CDR global and sum‐of‐box scores at baseline and longitudinal follow‐up were analyzed in relation to baseline amylin levels.ResultParticipants were followed for a mean 2.0 ± 1.1 years. Baseline whole blood amylin levels varied widely (mean of 8.8 ± 12.2 pg/ml). Seventy‐one participants had complete baseline and follow‐up data were included in this analysis. Of these, 20 had objective evidence for longitudinal decline. Participants with above vs below modal baseline amylin levels scored lower on baseline and follow‐up assessment scores including MMSE, MoCA, CDR global and CDR sum‐of box scores (p‐values all < 0.05). Annualized cognitive change scores (loss) for the MMSE (1.4 ± 2.4 vs. 0.3 ± 1.3; p < 0.05) and MoCA (1.5 ± 2.5 vs. 0.4 ± 1.8; p < 0.05) were greater in the above median baseline amylin level vs below median groups.ConclusionBaseline amylin whole blood levels are predictive of objective decline in MMSE and MoCA scores over periods as short as 2 years. These data suggest that the higher pancreatic hormone amylin may accelerate disease pathogenesis and cognitive decline as a result of altered pancreatic β‐cell function, potentially explaining, at least in part, the strong epidemiologic link between diabetes and dementia found across global observational cohorts. These data further suggest that the use of amylin biomarkers may serve as a useful tool for identifying subjects at high risk for short term cognitive decline. Additional work elucidating the role of amylin in degenerative disease cascades is warranted.

First‐in‐human [18F]D2‐Deprenyl‐PET imaging and GFAP evaluation as biomarkers of reactive astrogliosis in neurodegenerative diseases

AbstractBackgroundNeuroinflammation is a process occurring in neurodegenerative diseases, such as Alzheimer’s Disease (AD) and parkinsonian syndromes. In light of emerging disease modifying trials, objective biomarkers are urgently needed. Here, we target reactive astrogliosis for biomarker development in a pilot cohort of Multiple System Atrophy (MSA), in which key pathology and associated neuroinflammation are regionally more restricted than in AD, but more pronounced than in Parkinson’s Disease (PD). We combine glial fibrillary acidic protein (GFAP) as fluid‐based biomarker with [18F]D2‐Deprenyl‐(DED)‐PET imaging, a novel PET tracer targeting MAO‐B, for comprehensive characterization of reactive astrogliosis in this model disease.MethodGFAP levels were analyzed in plasma samples of 23 MSA and 22 PD patients, as well as in CSF samples of 14 MSA and 14 PD patients. In a subset of patients (4 MSA‐P, 7 MSA‐C and 3 PD), first‐in‐human [18F]DED‐PET imaging was performed. Fluid‐based and PET‐imaging biomarker levels were cross‐sectionally compared, followed by correlation to clinical disease severity as indicated by UMSARS (Unified Multiple System Atrophy Rating Scale) and MDS‐UPDRS (MDS Unified Parkinson’s Disease Rating Scale). Correlation between fluid‐based biomarkers and PET imaging signals was performed. Two additional patients were on rasagiline treatment and proved target engagement of [18F]DED‐PET imaging.Result[18F]DED‐PET imaging showed significantly higher SUVr signals in various regions of MSA when compared to PD. Signal increases were seen in phenotype‐specific target regions with higher putaminal tracer binding in MSA‐P and higher cerebellar tracer binding in MSA‐C patients (Fig. 1). Decreased [18F]DED‐PET tracer signal was detected in patients on rasagiline treatment, indicating sufficient blocking (Fig. 2). While CSF and plasma GFAP levels did not differ between MSA and PD, GFAP levels in both biofluids correlated with disease severity in MSA (p < 0.05), but not in PD.ConclusionWe present first‐in‐human data on a novel PET tracer to detect reactive astrogliosis in MSA. While [18F]DED‐PET imaging identifies disease‐ and entity‐specific regional astrogliosis, fluid biomarkers representing the overall level of astrogliosis appear to reflect clinical disease burden. Translation of these biomarkers into other neurodegenerative diseases, such as AD, should be pursued.

In vivo downregulation of pancreatic amylin improves brain function and reduces brain β amyloid pathology in APP/PS1 mice

AbstractBackgroundAmylin is a systemic hormone that is co‐secreted with insulin from pancreatic β‐cells. Amylin co‐aggregates with brain parenchymal and vascular b‐amyloid in persons with Alzheimer’s dementia. Cross‐sectional data show higher CSF and blood amylin levels are associated with increased frequency of cognitive impairment. The present study sought to determine how in vivo downregulation of amylin influences brain function during the development of Aβ pathology.MethodBecause mouse amylin is nonamyloidogenic, we developed an APP/PS1 mouse model in which the mouse amylin gene is replaced by the human amylin gene and is conditionally regulated by tamoxifen (TMX) injection, intraperitonially. At 3 months of age, human amylin‐expressing male mice were randomly assigned to either amylin downregulation group or control group (maintained amylin expression) (n = 10/group). Two months later, we assessed brain function with the novel object recognition test and performed comparative immunochemical Aβ analyses of hippocampal tissue by using MSD ELISA and immunohistochemistry (IHC).ResultMice with downregulated human amylin show enhanced recognition memory index (p < 0.001) and lower plasma amylin levels (p < 0.001) compared to those that continued to express human amylin. This was associated with decreased hippocampal levels of Aβ42 (p < 0.05) measured by MSD ELISA and decreased number of plaques (P < 0.01) measured by IHC.ConclusionAmylin downregulation in APP/PS1 mice improves memory. Molecular processes associated with improved memory involve decreased hippocampal Aβ pathology. Further studies are needed to understand how altered secretion of pancreatic amylin may influences the balance between brain Aβ accumulation and Aβ elimination from the brain.

Associations between brain iron deposition and structural Alzheimer’s disease signature in cognitively unimpaired adults

AbstractBackgroundIron dyshomeostasis appears to be an early event in the Alzheimer’s continuum. However, little is known how incipient cerebral iron deposition affects brain structure and function in cognitively unimpaired (CU) individuals. Here, we assessed the relationship between mean intensities in subcortical nuclei, a proxy measure for iron content, and regional cortical thickness as well as brain metabolism in middle‐aged CU individuals and sought for interactions with biomarkers of Alzheimer’s pathology.MethodWe included 288 CU adults from the ALFA+ cohort (Table 1). Mean intensities were quantified from T2‐weighted magnetic resonance images in 18 a priori defined subcortical nuclei. Due to the high correlations among regional intensities, we performed a principal component analysis to obtain a single measurement of cerebral iron load (Table 2). Cortical thickness (CT) of the “Alzheimer’s disease (AD) signature” composite region of interest (ROI) was assessed using FreeSurfer v6.0. [18F]fluorodeoxyglucose (FDG) PET scans were used to calculate the standardized uptake value ratio (SUVr) within a meta ROI. We created separate general linear models where cortical thickness and PET meta‐ROIs were the dependent variables, while the first principal component (PC1), age, sex, APOE‐ε4 status, and education level were entered as predictors. In additional models, CSF levels of amyloid‐beta ratio (Aβ42/40) and phosphorylated tau (p‐tau) were entered as covariates. We also tested the interaction between PC1 and CSF Aβ42/40 and pTau status. Statistical significance was set at p<0.05.ResultPC1 explained 47.64% of the variance of mean intensities in subcortical regions with lower values denoting higher iron concentration. Lower PC1 values were negatively associated with AD‐signature thickness (p=0.004), but not with brain glucose metabolism in the meta ROI (p=0.936). (Table 3. Figure 1). These results remained unchanged once AD core CSF biomarkers were entered into the model. No significant interactions with abnormal levels of CSF Aβ or p‐Tau were revealed with AD‐signature thickness or brain metabolism.ConclusionIn CU individuals, higher content of iron deposition is associated with reduced thickness, but not glucose metabolism, in cortical areas that typically show atrophy early in the Alzheimer’s continuum. This association was not modified by the presence of altered biomarkers of AD pathology.

APOE4 blood‐brain barrier dysfunction: relation to cognitive impairment and molecular mechanisms

AbstractBackgroundApolipoprotein E4 (APOE4), the major Alzheimer’s disease (AD) susceptibility gene, leads to accelerated BBB breakdown and degeneration of brain capillary pericytes that maintain BBB integrity both in humans and APOE4 transgenic mice. To what extent cerebrovascular effects of APOE4 contribute to preclinical and clinical decline is still understudied. Moreover, a comprehensive large‐scale analysis of cell‐specific mechanisms underlying APOE4 effects on the BBB is still lacking.MethodHere, we use neuroimaging and biomarkers approach in human APOE4 carriers and non‐carriers (ε3/ε3) and “multi‐omics” snRNAseq and proteomics analysis of the BBB in humanized APOE4 and APOE3 knock‐in mice.Result APOE4 carriers are distinguished from APOE3 homozygotes by BBB breakdown in the hippocampus and medial temporal lobe that is not related to CSF or PET measurements of Aβ or tau pathology. High baseline CSF levels of the BBB pericyte injury biomarker sPDGFRβ predicted future cognitive decline in APOE4 carriers but not in non‐carriers. APOE4 compared to APOE3 leads to an early disruption of the BBB transcriptome in APOE4 knock‐in mice followed by dysregulation in signaling networks including proteins regulating cell junctions, cytoskeleton, clathrin‐mediated transport, and translation in brain endothelium which paralleled an early, progressive BBB breakdown.ConclusionBBB breakdown contributes to APOE4 associated cognitive decline in humans independently of AD pathology. Disruption of the BBB cell‐specific signaling mechanisms could be an initial central contributor to APOE4‐mediated cerebrovascular disorder as shown in mouse model.

MR spectroscopic neurometabolite profile in aged rodents: a study in Sprague‐Dawley and Wistar rats, and C57bl/6J mice

AbstractBackgroundCognitive decline and Alzheimer’s disease (AD) are closely related to aging in human population and the need for translational biomarkers is of crucial importance. Several approaches have been proposed to study Alzheimer’s disease in rodent models, including transgenic mice and rats to model either amyloid‐ or tau‐pathologies. We have shown age‐related 1H‐MRS phenotype in female Fisher rats (22‐24 months, Bolognin et al. 2014 Neurobiol Aging:2134‐46) with reduced N‐acetyl aspartate (NAA), GABA and glutamate, and increased myo‐inositol together with other AD‐like biomarkers (increased CSF levels of AbPP and Tau, defect in Morris Water Maze, Khatoon et al 2015 J Alzheimer’s Disease: 557‐564). The aim of this study was to explore if similar 1H‐MRS phenotype is present in other strains of aged rats and mice to allow easier access to cohorts of aged rodents and enable utilization of different strains to model pathology.MethodEighteen male Sprague‐Dawley rats (n=10/8, 4/24 months), 24 male Wistar rats (n=12/12, 3.25 /21.75 months) and 23 male C57Bl/6J mice (n=12/11, 4.75/23 months) were used. Hippocampal MRS was performed at 11.7T magnet using PRESS sequence and metabolites analyzed using LCModel.ResultAlthough the evaluation was done at slightly different ages, all three models shared a similar phenotype in hippocampal metabolites, i.e. decreased GABA and glutamate, and increased glutamine and myo‐inositol. NAA was significantly reduced in aged Wistar rats and C57Bl/6J mice whereas the SD rats showed only non‐significant trend of decrease.ConclusionBased on the current data, the MRS phenotype is remarkably repeatable in aged rats (SD, Wistar) and in aged C57Bl/6J mice. Furthermore, the pattern of increased myo‐inositol with decreased levels of glutamate and NAA is descriptive of human AD. Aged rodents can therefore model biochemical changes potentially related to natural aging/AD.

Validation and utility of plasma neurofilament light as a biomarker for vascular cognitive impairment

AbstractBackgroundNeurofilament light chain (NfL) is a broad marker of neuroaxonal injury that is elevated in the CSF in those with vascular cognitive impairment and dementia (VCID). Blood and CSF levels highly correlate, making it an attractive peripheral marker for VCID pathology. As part of the MarkVCID consortium, we sought to evaluate the instrumental validity of plasma NfL using the Quanterix Simoa platform and assess its validity for risk stratification in clinical trials of VCID.MethodPlasma NfL was measured using HD‐X and HD‐1 Simoa instruments. For instrumental validation, we used samples from the MarkVCID consortium to evaluate intra‐ and inter‐plate reliability, test‐retest repeatability, and inter‐site reproducibility. We used linear regression models to assess the association of NfL with general cognitive function (GCF) as the primary outcome. In secondary analyses we assessed associations with white matter hyperintensities (WMH), an established small vessel disease marker. Models were adjusted for potential confounders. The clinical validation included established cohorts from the CHARGE consortium (i.e., CARDIA, ARIC, FHS, AGES; n=4,772), the UKY ADRC (n=350), and the UCD ADRC (n=196). Additional analyses are underway in MarkVCID sites.ResultWe found low coefficients of variation (average CV<12%), high inter‐site reproducibility (overall ICC = 0.93) and high repeatability in blood samples drawn within 30 days (ICC=0.968). There was high consistency across Quanterix instruments (HD‐X and HD‐1; R2≥0.98) and kits (N4PA and single molecule NfL; ICC≥0.81). We observed consistent significant associations between higher NfL concentrations and worse GCF in CHARGE cohorts (meta‐analysis β=‐0.11; [95% CI ‐0.06; ‐0.17]), the UKY ADRC (β=‐0.16; [95% CI ‐0.27; ‐0.05]) and the UCD ADRC (UCD: β=‐0.28; [95% CI ‐0.48; ‐0.08). Secondary analyses revealed significant associations between elevated NfL concentrations and higher WMH burden in CHARGE cohorts and the UCD ADRC (P<0.01).ConclusionOur results suggest plasma NfL can be reliably measured using the Quanterix platform, making this marker ideal for multi‐site clinical trials. We observed consistent associations for plasma NfL concentrations with cognition and WMH across independent samples, providing evidence that plasma NfL can be a useful biomarker for stratification in VCID trials.

Associations between brain iron deposition and structural Alzheimer’s disease signature in cognitively unimpaired adults

AbstractBackgroundIron dyshomeostasis appears to be an early event in the Alzheimer’s continuum. However, little is known how incipient cerebral iron deposition affects brain structure and function in cognitively unimpaired (CU) individuals. Here, we assessed the relationship between mean intensities in subcortical nuclei, a proxy measure for iron content, and regional cortical thickness as well as brain metabolism in middle‐aged CU individuals and sought for interactions with biomarkers of Alzheimer’s pathology.MethodWe included 288 CU adults from the ALFA+ cohort (Table 1). Mean intensities were quantified from T2‐weighted magnetic resonance images in 18 a priori defined subcortical nuclei. Due to the high correlations among regional intensities, we performed a principal component analysis to obtain a single measurement of cerebral iron load (Table 2). Cortical thickness (CT) of the “Alzheimer’s disease (AD) signature” composite region of interest (ROI) was assessed using FreeSurfer v6.0. [18F]fluorodeoxyglucose (FDG) PET scans were used to calculate the standardized uptake value ratio (SUVr) within a meta ROI. We created separate general linear models where cortical thickness and PET meta‐ROIs were the dependent variables, while the first principal component (PC1), age, sex, APOE‐ε4 status, and education level were entered as predictors. In additional models, CSF levels of amyloid‐beta ratio (Aβ42/40) and phosphorylated tau (p‐tau) were entered as covariates. We also tested the interaction between PC1 and CSF Aβ42/40 and p‐Tau status. Statistical significance was set at p<0.05.ResultPC1 explained 47.64% of the variance of mean intensities in subcortical regions with lower values denoting higher iron concentration. Lower PC1 values were negatively associated with AD‐signature thickness (p=0.004), but not with brain glucose metabolism in the meta ROI (p=0.936). (Table 3. Figure 1). These results remained unchanged once AD core CSF biomarkers were entered into the model. No significant interactions with abnormal levels of CSF Aβ or p‐Tau were revealed with AD‐signature thickness or brain metabolism.ConclusionIn CU individuals, higher content of iron deposition is associated with reduced thickness, but not glucose metabolism, in cortical areas that typically show atrophy early in the Alzheimer’s continuum. This association was not modified by the presence of altered biomarkers of AD pathology.

Soluble TAM receptor biomarkers: Neuroprotection in AD neuroinflammation?"

AbstractBackgroundWhile neuroinflammation is reckoned as a pathological hallmark of AD, research on suitable biomarkers is still ongoing. Here, we report on findings from the DZNE DELCODE, Fundacío ACE and other cohorts demonstrating distinct inflammatory biomarker profiles in CSF and serum. Intriguingly, within these profiles, soluble TAM receptor markers are elevated in neurodegeneration but still relate to protection of cognition and brain structure.MethodWe investigated a panel of 20 experimental biomarkers utilizing customized immunoassays in CSF and serum samples of DELCODE and other cohorts with a total of >1000 subjects, including healthy controls, subjective cognitive decline, mild cognitive impairment, AD relatives and AD patients. Data were analyzed in relation to clinical and biomarker‐based staging as well as cognitive and structural imaging composite scores, adjusted for covariates such as age.ResultVarious inflammatory markers, when measured in CSF, were found to correlate to tau isoforms and other neurodegeneration markers and to be elevated in pre‐dementia stage subjects with already pathological tau levels. Among these, soluble TAM receptors sAXL and sTyro3 were related to preserved cognition and brain structure. In serum, inflammatory markers displayed different interrelations, with individual proteins in serum showing no or modest correlation to their CSF counterparts or other AD biomarkers. Noteworthy, serum soluble AXL increased only in AD subjects and related to decreased structure and function.ConclusionNeurodegeneration in AD is accompanied by a pattern of elevated inflammatory CSF biomarkers. These proteins likely represent cellular responses to neuronal damage and are evident already at pre‐dementia stages of disease. Within this response, upregulation of TAM receptors in the brain could serve to regulate neuroinflammation and promote cellular survival, with receptor turnover resulting in elevated CSF levels. Noteworthy, blood signatures of the same biomarkers, though not without significance, show different patterns of relations towards disease features, likely reflecting distinct peripheral cellular origins and biological functions of the respective proteins. These findings point towards TAM signalling as potential target for future therapeutic intervention, especially in subjects with pre‐dementia neurodegeneration phenotypes. As such, CSF soluble TAM levels might provide promising readout biomarkers.

Baseline White Matter Neuroinflammation Predicts Cognitive Decline in Alzheimer Disease

AbstractBackgroundNeuroinflammation, an intrinsic immune response of the nervous system, is important in an early phase of Alzheimer Disease (AD) pathogenesis. However, it is largely unclear how neuroinflammation promotes the clinical progression of AD. Extracellular water edema (ECW) from Neuro‐inflammation imaging (NII), a diffusion‐based MRI approach for neuroinflammation, has been utilized to asses white matter (WM) neuroinflammation in AD. This study aims to investigate the relationship between WM neuroinflammation and longitudinal cognitive changes in AD.MethodThis study included 286 participants who were enrolled in ongoing research at the Knight ADRC at Washington University in Saint Louis. The CSF levels of Aβ42/Aβ40 and ptau181 measured with the automated Lumipulse platform were used to categorize the participants as being positive or negative amyloid (A) and tau (T), respectively (Table 1). As measures of cognitive performance, the Knight ADRC Preclinical Alzheimer Cognitive Composite (Knight ADRC‐PACC) and a Global composite score were employed for each individual. The rates of change of cognitive measures were calculated for each individual. The NII was acquired with a multi‐b value scheme (bmax =1400s/mm2 and 25 directions). The total WM neuroinflammation (NII‐ECW) was obtained using the TBSS (http://www.fmrib.ox.ac.uk/fsl) based WM skeleton. Randomise in FSL was utilized to examine voxel‐wise relationships between NII‐ECW and the rate of change of cognitive measures. Non‐parametric Kruskal‐Wallis and Chi‐square tests were employed for comparing continuous and categorical variables of the participants’ demographics, respectively. The group differences of NII‐ECW were tested using one‐way ANOVA. All statistical tests were conducted in R (R Core Team, 2020). Age, sex, and APOE ε4 carrier status were adjusted as covariates.Result Table 1 summarizes demographic data. When compared to the A‐T‐ group, the A+T+CDR0 and A+T+CDR0.5 groups had higher NII‐ECW (Figure 1). When the A+T+CDR1 group was compared to the other groups, there was no group difference in NII‐ECW. There were substantial negative associations between the NII‐ECW and the rates of change of cognitive measures in the widespread WM regions (Figure 2).ConclusionOur data suggest that neuroinflammation increases early in preclinical AD and decreases later in the disease. Furthermore, baseline neuroinflammation as measured by NII‐ECW predicts cognitive decline in AD.

ABCA7‐reducing mutation carriers have reduced CSF amyloid biomarker levels, suggestive of increased amyloid deposition

AbstractBackgroundThe Alzheimer’s disease (AD) risk gene ABCA7 has suggested functions in lipid metabolism and the immune system. Rare premature termination codon (PTC) mutations and an expansion of a variable number of tandem repeats (VNTR) polymorphism in the gene, both likely cause a lower ABCA7 expression and hereby increased risk for AD. However, the exact mechanism‐of‐action remains unclear. By studying CSF biomarkers reflecting different types of AD‐related pathological processes, we aim to get a better insight in those processes and establish a biomarker profile of mutation carriers.MethodThe study population consisted of 228 AD patients (27 PTC mutation and 16 pathogenic expansion carriers) for whom CSF was available and ABCA7 sequencing and VNTR genotyping had been performed. CSF levels of amyloid β (Aβ) 40 and 42, sAPP‐α and ‐β, YKL‐40 and hFABP were determined using ELISA and Meso Scale Discovery assays. We compared differences in levels of these biomarkers AD patients with or without an ABCA7 PTC mutation or expansion, and further stratified on APOE e4 status.ResultCarriers of ABCA7 mutations/expansions had significantly lower Aβ42 levels (p= 0.0031) and amyloid ratio (p=0.020) compared to non‐carrier patients, and were threefold more likely to have abnormal Aβ42 values. The effect on amyloid biomarkers remained significant when considering PTC mutations or VNTR expansions separately. APOE e4 carriers had significantly lower Aβ42 (p=0.0013) and amyloid ratio (p<0.001) compared to non‐APOE e4 carriers. When combined, both APOE e4 allele and ABCA7 carrier status influenced amyloid ratio and Aβ42 levels. Remarkably, within non‐APOE e4 carriers, ABCA7 mutation/expansion carriers did have significantly reduced Aβ42 levels (mean=540 pg/mL) compared to ABCA7 non‐carriers (812 pg/mL; p=0.0051), attaining lower levels as e4 carriers (612 pg/mL). Finally, in carriers of the pathogenic expansion we observed lower YKL40 levels (p=0.011), suggesting reduced neuroinflammation.ConclusionOur results highlight that carriers of ABCA7 PTC mutations and repeat expansions show more pronounced abnormalities in CSF amyloid beta markers than non‐carrier patients, especially in non‐APOE e4 carriers. Expansion carriers also had a decrease in neuroinflammation marker YKL40. Our results suggest that reduced ABCA7 expression leads to increase in amyloid pathology and potentially a reduced inflammatory response to damage.

Baseline White Matter Neuroinflammation Predicts Cognitive Decline in Alzheimer Disease

AbstractBackgroundNeuroinflammation, an intrinsic immune response of the nervous system, is important in an early phase of Alzheimer Disease (AD) pathogenesis. However, it is largely unclear how neuroinflammation promotes the clinical progression of AD. Extracellular water edema (ECW) from Neuro‐inflammation imaging (NII), a diffusion‐based MRI approach for neuroinflammation, has been utilized to asses white matter (WM) neuroinflammation in AD. This study aims to investigate the relationship between WM neuroinflammation and longitudinal cognitive changes in AD.MethodThis study included 286 participants who were enrolled in ongoing research at the Knight ADRC at Washington University in Saint Louis. The CSF levels of Aβ42/Aβ40 and ptau181 measured with the automated Lumipulse platform were used to categorize participants as being positive or negative amyloid (A) and tau (T), respectively (Table 1). As measures of cognitive performance, the Knight ADRC Preclinical Alzheimer Cognitive Composite (Knight ADRC‐PACC) and a Global composite score were employed for each individual. The rates of change of cognitive measures were calculated for each individual. The NII was acquired with a multi‐b value scheme (bmax =1400s/mm2 and 25 directions). The total WM neuroinflammation (NII‐ECW) was obtained using TBSS (http://www.fmrib.ox.ac.uk/fsl) based WM skeleton. Randomise in FSL was utilized to examine voxel‐wise relationships between NII‐ECW and the rate of change of cognitive measures. Non‐parametric Kruskal‐Wallis and Chi‐square tests were employed for comparing continuous and categorical variables of the participants’ demographics, respectively. The group differences of NII‐ECW were tested using one‐way ANOVA. All statistical tests were conducted in R (R Core Team, 2020). Age, sex, and APOE ε4 carrier status were adjusted as covariates.ResultTable 1 summarizes demographic data. When compared to the A‐T‐ group, the A+T+CDR0 and A+T+CDR0.5 groups had higher NII‐ECW (Figure 1). When the A+T+CDR1 group was compared to the other groups, there was no group difference in NII‐ECW. There were substantial negative associations between the NII‐ECW and the rates of change of cognitive measures in the widespread WM regions (Figure 2).ConclusionOur data suggest that neuroinflammation increases early in preclinical AD and decreases later in the disease. Furthermore, baseline neuroinflammation as measured by NII‐ECW predicts cognitive decline in AD.

Relationship between cytokines and β‐amyloid and Tau protein in the CSF of patients with Alzheimer's disease, amnestic mild cognitive impairment, and individuals without subjective cognitive impairment

AbstractBackgroundThe neuroinflammation process is one of the main pathological features of Alzheimer's disease (AD). In the course of AD, the deposits of β‐amyloid plaques and neurofibrillary tangles lead to over‐activation of the microglia, resulting in increased production of pro‐inflammatory and anti‐inflammatory cytokines that may contribute to neuronal dysfunction and cell death. Currently, several efforts have been made to discover the role of cytokines in AD's pathogenesis and the relationship between these inflammatory factors and the presence of AD's main biological markers (1). The present study aimed to determine the quantitative correlation between cytokines, β‐amyloid, and Tau proteins and the cognitive status of the participants.MethodCSF was collected by lumbar puncture from 80 older individuals with clinically defined AD (n=36), with amnestic mild cognitive impairment (aMCI) (n=24), and without objective cognitive impairment (n=20). CSF levels of β‐amyloid and p‐tau and t‐Tau and 27 cytokines were determined using the Luminex xMAP technique. Correlations were made between the cytokines, the β‐amyloid and Tau proteins levels, and the Mini‐Mental State test (MEEM).Resultconsidering all individuals, there was a significant positive correlation between Aβ42, IL‐4 and IL‐8; p‐Tau positively correlated with G‐CSF and GM‐CSF and finally p‐Tau/Aβ42 negatively correlated with IL8. The MEEM was correlated negatively with Eotaxin, IL‐6 and IL‐15. Focusing only in the AD group, there was a positive correlation for Aβ42 with IL‐4, IL‐8 and negatively with IL‐17; t‐Tau correlated negatively with IL‐1ra and IL‐5; p‐Tau/Aβ42 positively correlated with IL‐17 and negatively with IL‐8 and IP10. The MEEM showed a positive correlation with IL‐4. In the control group, Aβ42 and VEGF had a negative correlation; p‐Tau negatively correlated with TNF‐α; p‐Tau/Aβ42 were correlated positively with GM‐CSF, IL‐1β and IL‐6. The MEEM did not present any correlation. Between the aMCI group, t‐Tau was correlated positively with PDGF‐BB, and the MEEM was correlated negatively with Eotaxin.ConclusionChanges in the neuroinflammatory profile are more prominent in AD patients compared to individuals without subjective cognitive impairment and those with aMCI.

The level of homocysteine in amyotrophic lateral sclerosis: a systematic review and meta-analysis.

To investigate the differences of the level of homocysteine (Hcy) between ALS patients and controls. PubMed, EMBASE, OVID, and other databases were searched systematically up to October 2022 for relevant reports about the level of Hcy, folic acid, and vitamin B12 (VB12) among ALS patients. Two reviewers screened and selected the titles and abstracts of the studies independently during the database searches and performed full-text reviews and extracted available data. The MD (mean difference) and 95%CI (credibility interval) of the level of Hcy, folic acid, and VB12 between ALS group and control group were calculated. Pooled results of nine studies including 812 ALS patients and 2632 controls showed that the MD in plasma levels of HCY between ALS patients and controls was 1.56 (95%CI: - 0.07, 3.19) μmol/L with remarkable heterogeneity (I2 = 94%). The mean CSF levels of Hcy among ALS patients were significantly higher than that of controls (MD: 0.23, 95%CI: 0.21, 0.24μmol/L) with no significant heterogeneity (I2 = 0%). No significant difference in the plasma level of folic acid (MD: - 0.52, 95%CI: - 1.89, 0.84ng/mL) or VB12 (MD: - 9.76, 95%CI: - 83.41, 63.89) was found between ALS patients and controls. There was no significant difference in the plasma level of Hcy, folic acid, or VB12 between ALS patients and controls. The CSF level of Hcy among ALS population was remarkably higher than that among controls. Vitamin supplements including folate and VB12 might be recommended to ALS patients with the complication of deficiencies.

Study of CSF C-Reactive Protein for the Differentiation of Bacterial Meningitis from Aseptic Meningitis in Children

Background: Acute meningitis is a major cause of death, and disability worldwide. Differentiating bacterial from nonbacterial meningitis is very important in deciding on treatment. Bacterial meningitis is a life-threatening neurological condition, and needs prompt parenteral antibiotics, compared to viral, and aseptic meningitis which carries relatively better outcomes. Objective: To identify the importance of Cerebrospinal fluid C- reactive protein (CSF-CRP) to establish the diagnosis of ABM. Method: This study was conducted from 01 January 2017 to 30th June 2017 at the indoor department of Pediatric Medicine at Bangladesh Sishu Hospital & Institute (BSH & I) to the measure of CSF C-Reactive protein for the differentiation of bacterial meningitis from aseptic meningitis in children. One hundred patients had participated after meeting the inclusion, and exclusion criteria. Patients were selected by purposive sampling. Ethical clearance was obtained from the National Health Research Ethics Committee, BangladeshShishu Hospital& Institute, Dhaka. Results: Out of 57 cases of bacterial meningitis, 22 cases were culture-negative, and 35 cases were culture-positive. 22 cases (62.85%) out of 35 cases culture positive were Streptococcus Pneumoniae followed by 08 cases (22.85%) were Neisseria Meningitis, Haemophilus Influenza 3 cases (8.57%), E.coli were 02 cases (5.71%). WBC count & PMN (%) were increased significantly in bacterial meningitis, compared to aseptic meningitis. Protein and glucose levels in CSF were not significantly different between bacterial meningitis, and the aseptic meningitis group (Table 2). In the case of bacterial meningitis, in 51(89.47%) cases out of 57, the CSF CRP test was truly positive, mean±SD 21.7±10.9, and false negative were only 6 cases (10.52%). In aseptic meningitis 39 cases (90.69%) out of 43 cases, the CSF-CRP test was truly negative, and false positives were 04 cases (9.30%). (Table-4) shows outcome in the meningitis group showed .....

How to Treat Isolated Leptomeningeal Relapse of Multiple Myeloma 11 Years after Autologous Stem Cell Transplantation (ASCT)

Post transplant relapse of Multiple Myeloma (MM) in the central nervous system (CNS) is rare and it is almost always associated with systematic relapse and in most instances, shortly after initial treatment. We did not encounter reports of relapse isolated to the CNS ten years post-transplant. In October 2009, a 49-year-old male presented with an IgG lambda MM, ISS II. He was treated with Bortezomib/Dexamethasone, autologous PBSCT, followed by two years maintenance with Lenalidomide, attaining stringent CR, confirmed by PET/CT. He discontinued follow up and returned after 11y/8m progression free survival, in June 2021 with paraplegia due to cauda equina syndrome. NMR consistent with leptomeningeal infiltration, single focal intramedullary lesion at L1 level without bone affectation. No MM defining criteria (CRAB). Normal levels of serum Immunoglobulins (IGs), serum and urine immunofixation, and serum free light chains. Flow cytometry negative in bone marrow. Spinal tap was unsuccessful and through an Ommaya reservoir, that was placed after NMR showed evidence of cranial leptomeningeal involvement, CSF showed infiltration by countless malignant plasma cells. Patient received immediate conformational radiotherapy and biweekly IT methotrexate and hydrocortisone. A month later his course was complicated by left leg proximal deep vein thrombosis and pulmonary embolism which was treated with Apixaban. Given the rarity of this type of relapse, we questioned the appropriateness of the treatment and searched the literature with respect to the accessibility of the CNS by the different novel drugs used to treat MM in order to determine the most effective strategy. In addition to corticosteroids, there is clinical evidence that thalidomide crosses the blood-brain barrier (BBB), in murine models pomalidomide also has good penetration into the CNS. Both have a penetration of 30 to 40% into the CSF. Among proteasome inhibitors, only marizomib has been observed to cross the BBB in a murine model, while bortezomib does not. With respect to anti CD38 monoclonal antibodies, mass spectrometry at 12, 15, and 19 days after daratumumab infusion showed antibody levels in CSF 71 times less than in serum on the three sample days. It is not known if weekly doses of daratumumab could attain therapeutic levels in CSF. We found only 14 cases of isolated CNS relapse in patients with MM treated with ASCT with a median interval between transplant and relapse of 3 months (0.5-96m), with only one reported relapse 7.5 years after autologous transplant and the median overall survival was only 3 months. Two cases died in less than a month and only one case survived for a year after the CNS relapse.To date, our patient has received 12 cycles of Pomalidomide/dexamethasone with progressive improvement, now he is able to carry on his life unassisted and there is no evidence of MM relapse anywhere. The rarity of this case scenario highlights the lack of knowledge regarding the best approach to CNS MM relapse. There is no evidence of the effectiveness of methotrexate and Ara C, in MM, and no novel drug can be instilled into the CSF. We conclude that the systemic use of pomalidomide and dexamethasone should be the best approach of MM isolated CNS relapse. Further investigations will clarify if other novel drugs are active in this context.

Protective effects of early exercise on neuroinflammation, and neurotoxicity associated by traumatic brain injury: a behavioral and neurochemical approach

Objective The benefits of exercise in TBI have been proven. However, the time-dependent effects of exercise initiation and the involved mechanisms are controversial. We investigated the effects of preconditioning, continuous, early, and delayed treadmill exercise on motor behavior, brain edema, inflammation, and oxidative stress in experimental traumatic brain injury (TBI). Materials and Methods 48 male rats were assigned into two groups: sedentary control (Sham and TBI) and exercise groups: 1MB (preconditioning, initiation beginning at 1 month before trauma), 1MBA (continuous, initiation beginning at 1 month before and continuing 1 month after trauma), 24hA (early, initiation beginning at 24 h after trauma), and 1WA (delay, initiation beginning at 1 week after trauma). The rats in exercise groups were forced to run on a treadmill five days a week for 30 min per day. Rotarod and open file were used to assess motor behavior. ELISA was also used to measure total antioxidant capacity (TAC), tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) in serum and CSF. Results Exercise significantly decreased neurological impairments, motor deficits, and apoptosis compared with the sedentary group. Early (within 24 h) and ongoing (1 MBA) exercise significantly improved motor behavior after TBI. In addition, these exercise programs inhibited brain edema and the number of apoptotic cells. MDA and TNF-α levels increased in all exercise groups, but the effects were greater after early exercise than after delayed exercise, resulting in a significant decrease in TAC levels in serum and CSF. We discovered a positive correlation between MDA, TAC, and TNF-α concentration in serum and CSF. Conclusion Our finding suggests that early exercise (24hA) and 1MBA groups afford neuroprotection and reduce the second injury consequence, probably by reducing neuronal apoptosis and oxidative stress.

A Plasma Circular RNA Profile Differentiates Subjects with Alzheimer's Disease and Mild Cognitive Impairment from Healthy Controls.

The most frequently used biomarkers to support the diagnosis of Alzheimer's Disease (AD) are Aβ42, total-Tau, and phospho-tau protein levels in CSF. Moreover, magnetic resonance imaging is used to assess hippocampal atrophy, 18F-FDG PET to identify abnormal brain metabolism, and PET imaging for amyloid deposition. These tests are rather complex and invasive and not easily applicable to clinical practice. Circulating non-coding RNAs, which are inherently stable and easy to manage, have been reported as promising biomarkers for central nervous system conditions. Recently, circular RNAs (circRNAs) as a novel class of ncRNAs have gained attention. We carried out a pilot study on five participants with AD and five healthy controls (HC) investigating circRNAs by Arraystar Human Circular RNA Microarray V2.0. Among them, 26 circRNAs were differentially expressed (FC ≥ 1.5, p < 0.05) in participants with AD compared to HC. From a top 10 of differentially expressed circRNAs, a validation study was carried out on four up-regulated (hsa_circRNA_050263, hsa_circRNA_403959, hsa_circRNA_003022, hsa_circRNA_100837) and two down-regulated (hsa_circRNA_102049, hsa_circRNA_102619) circRNAs in a larger population. Moreover, five subjects with mild cognitive impairment (MCI) were investigated. The analysis confirmed the upregulation of hsa_circRNA_050263, hsa_circRNA_403959, and hsa_circRNA_003022 both in subjects with AD and in MCI compared to HCs. We also investigated all microRNAs potentially interacting with the studied circRNAs. The GO enrichment analysis shows they are involved in the development of the nervous system, and in the cellular response to nerve growth factor stimuli, protein phosphorylation, apoptotic processes, and inflammation pathways, all of which are processes related to the pathology of AD.

Deferoxamine Prevents Neonatal Posthemorrhagic Hydrocephalus Through Choroid Plexus-Mediated Iron Clearance.

Posthemorrhagic hydrocephalus occurs in up to 30% of infants with high-grade intraventricular hemorrhage and is associated with the worst neurocognitive outcomes in preterm infants. The mechanisms of posthemorrhagic hydrocephalus after intraventricular hemorrhage are unknown; however, CSF levels of iron metabolic pathway proteins including hemoglobin have been implicated in its pathogenesis. Here, we develop an animal model of intraventricular hemorrhage using intraventricular injection of hemoglobin at post-natal day 4 that results in acute and chronichydrocephalus, pathologic choroid plexus iron accumulation, and subsequent choroid plexus injury at post-natal days 5, 7, and 15. This model alsoresults in increased expression ofaquaporin-1, Na+/K+/Cl- cotransporter 1, andNa+/K+/ATPase on the apical surface of the choroid plexus 24h post-intraventricular hemorrhage. We use this model to evaluate a clinically relevant treatment strategy for the prevention of neurological sequelae afterintraventricular hemorrhageusing intraventricular administration of the iron chelator deferoxamine at the time of hemorrhage. Deferoxamine treatment prevented posthemorrhagic hydrocephalus for up to 11days after intraventricular hemorrhage and prevented the development of sensorimotor gating deficits. In addition, deferoxamine treatment facilitated acute iron clearance through the choroid plexus and subsequentlyreduced choroid plexus iron levels at 24hwith reversal of hemoglobin-induced aquaporin-1 upregulation on the apical surface of the choroid plexus. Intraventricular administration of deferoxamine at the time of intraventricular hemorrhage may be a clinically relevant treatment strategy for preventing posthemorrhagic hydrocephalus and likely acts through promoting iron clearance through the choroid plexus to prevent hemoglobin-induced injury.