Glial Fibrillary Acid Research Articles

Ameliorative Effects of FMRFamide on 3,4-Methylenedioxyl-Methamphetamine /Tramadol-Induced Neurodegeneration in the Hippocampus

Objective: Tramadol and 3,4-methylenedioxy-methamphetamine (MDMA) use over an extended period is linked to deficits in memory encoding and retrieval. We aimed to determine the neurotoxic effects of co-administration of MDMA and tramadol (TRAM) on hippocampal function and investigate the potential of FMRFamide in attenuating resulting alterations in the Wistar rat model. Methods: Thirty adult male Wistar rats were grouped into six (n=5): Control, FMRFamide, TRAM, MDMA, TRAM+MDMA, and TRAM + MDMA + FMRFamide groups. The opiates were administered orally at 20mg/kg each, while 2mg/kg of FMRFamide was administered intraperitoneally for 12 days using normal saline as a vehicle. The Barnes and Morris water mazes were used to evaluate spatial learning and memory functions, followed by H&E staining, and immunohistochemical staining for glial fibrillary acid protein (GFAP). Results: The opiates significantly increased total latencies in the Barnes Maze test, indicating that short- and long-term memory functions were impaired. Also, high levels of escape latency were observed following MDMA administration, suggesting that MDMA reduced the spatial navigation ability of the animals. These discrepancies were noticeably extreme in animals that received co-administration of opiates. However, FMRFamide showed significant potential in attenuating the damage induced by opiates, thus repairing and restoring memory formation and retention functions. Conclusion: FMRFamide may attenuate the Tramadol- and MDMA-mediated memory dysfunction by enhancing cholinergic and glutaminergic synthesis and transporting and restoring exploratory and navigational abilities in the hippocampus of male Wistar rats.

Post‐mortem MRI white matter hyperintensities are associated with cortical astrocytopathy and water channel expression in the oldest‐old

AbstractBackgroundCerebrovascular small vessel disease, a common cause of cognitive impairment in older individuals, is characterized by the presence of MRI white matter hyperintensities (WMH). Our previous MRI‐targeted histopathological studies have found WMHs and the surrounding NAWM penumbra to be associated with glial markers. This study aims to assess the relationship between cortical markers of glial dysfunction and post‐mortem (PM) MRI WMH.MethodLeft brain hemispheres were obtained from 45 Oregon Alzheimer’s Disease Research Center subjects >/ = 80 years of age without significant AD pathology. Intact and sliced hemispheres were scanned at 7T MRI. MRI scans were used to target histological sampling. Slides were stained for glial fibrillary acid protein (GFAP), ionized calcium binding adapter molecule‐1 (IBA1), aquaporin‐1 (AQP1), aquaporin‐4 (AQP4), vimentin and amyloid‐beta (ABETA). Slides were co‐registered to MRI. Tissue masks were hand‐drawn to delineate white matter and cortex. Cortical ROIs were quantified for mean pixel value (AQP1, AQP4, GFAP, and Vimentin) or area coverage (IBA1, ABETA). Cassettes with no local WMH were compared with those in the top third of slide WMH coverage (187 cassettes). Global WMH burden was dichotomized at the mean. Linear mixed‐effects models regressed stain quantification on local WMH (in slide) and global WMH burden, with a random effect for staining batch (levels = 4). The final model controlled for age at death and ABETA expression within a slide. Interactions between local and global WMH were included where appropriate.ResultHigh local WMH burden was associated with greater cortical vimentin (p = 0.036), GFAP (p = 0.066), and AQP4 (p = 0.004), while high global WMH burden was associated with greater IBA1 (p = 0.034) and AQP1 (p = 0.071). An interaction was identified between local and global WMH burden for AQP1 (p<0.10), such that in subjects with high global WMH burden, high local WMH burden was associated with higher AQP1. Greater local cortical ABETA was associated with cortical AQP1 (p = 0.004) expression.ConclusionIn oldest‐old individuals without significant AD pathology, high local and global PM‐MRI WMH burden is associated with cortical astrocytopathy, including increased water channel expression and inflammation. Findings implicate WMH as a state marker of widespread cortical pathology that may confer increased vulnerability to cognitive decline with advanced age.

Plasma‐based biomarkers of Alzheimer’s Disease in a multi‐ethnic population: A Cross‐Sectional analysis from the WHICAP Study

AbstractBackgroundBlood‐based biomarkers have the unique potential to make diagnoses along the Alzheimer’s Disease (AD) continuum. The value of these plasma‐based biomarkers in AD among different race and ethnicity, sex, and genetic status groups needs to be evaluated.MethodThe study included 603 participants of the Washington Heights Inwood Columbia Aging Project, a community‐based cohort study. We measured six AD biomarkers, including phosphorylated Tau‐181 (PTau181), total Tau, Amyloid Beta (Aβ) 40, Aβ42, Glial Fibrillary Acid Protein (GFAP), and Neurofilament Light Chain (NfL). We compared the biomarker levels among 95 individuals clinically diagnosed with AD, 167 individuals with Mild Cognitive Impairment (MCI), and 341 cognitively unimpaired individuals using linear regression models, adjusting for age, sex, race and ethnicity, years of education, APOE ɛ4 status, and sample storage time. We further examined whether the association between biomarkers and clinical diagnosis differed by racial and ethnic groups, sex, and APOE ɛ4 status.ResultThe participants were on average 80.23 (SD = 6.77) years old. Participants self‐identified as non‐Hispanic White (24.03%), non‐Hispanic Black (24.70%), or Hispanic (51.21%), with 414 women (68.66%). AD participants had elevated total tau levels (β = 0.303, p = 0.029), NfL (β = 0.472, p <0.001), and GFAP (β = 0.467, p < 0.001) compared to cognitively unimpaired participants. Individuals with MCI also had higher levels of total tau (β = 0.258, p = 0.016), NfL (β = 0.234, p = 0.035), and GFAP (β = 0.248, p = 0.02) than controls. Stratified analyses showed that men with MCI had higher NfL levels than cognitively unimpaired individuals (β = 0.123, p = 0.008). In women, there were no observable differences in NfL levels between individuals with MCI and controls (β = 0.014, p = 0.669). Among APOE e4 carriers, individuals with MCI had higher levels of NfL than unimpaired controls (β = 0.157, p = 0.006). This was not observed in APOE e4 non‐carriers (β = 0.025, p = 0.397).ConclusionConsistent with the literature, we found plasma AD biomarkers including total tau, NfL, and GFAP were higher in MCI and AD compared with cognitively unimpaired individuals. Among men and APOE e4 carriers, we found higher NfL levels in MCI individuals than in cognitively unimpaired individuals.

Longitudinal change of plasma biomarkers with incident mild cognitive impairment or Alzheimer’s disease in a multi‐ethnic cohort

AbstractBackgroundThe utility of plasma‐based Alzheimer’s biomarkers in differentiating cognitively healthy individuals from those with Mild Cognitive Impairment (MCI) or Alzheimer’s disease (AD) has been widely investigated in cross‐sectional studies. There are fewer data on longitudinal change of these biomarkers over time, particularly in multi‐ethnic cohorts.MethodBased on a community‐based, multi‐ethnic cohort study, the Washington Heights Inwood Columbia Aging Project, we included 610 cognitively normal individuals with three plasma samples collected over a mean period of 6.7 years. We used AD biomarkers, including Aβ40, Aβ42, tau, phosphorylated tau‐181 (P‐tau181), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL), and two calculated ratio measures (Aβ42/Aβ40, P‐tau181/Aβ42). During the follow‐up, 156 individuals developed MCI, 50 developed AD, and 404 remained cognitively unimpaired. We used generalized estimating equations to examine whether those who developed MCI and AD had different rates of change in plasma biomarkers than controls. Analyses were adjusted for age, years of education, sex, race and ethnicity, and APOE ɛ4 status. Similar analyses were performed to examine whether the rate of biomarker change differed by race and ethnicity, sex, and APOE ɛ4 status.ResultThe initial mean age of individuals was 73.1 (SD = 5.6) years, 419 (69%) were women, and 25.9% carried APOE e4. Individuals self‐identified as non‐Hispanic White (28.9%), non‐Hispanic Black (25.4%), or Hispanic (45.7%). Compared to controls, individuals with incident MCI had an accelerated increase in P‐tau181 (b = 0.029, p = 0.048), NfL (b = 0.027, p = 0.010), GFAP (b = 0.029, p = 0.002), and a more rapid decrease in Aβ42/Aβ40 ratio (b = ‐0.015, p = 0.033). Individuals with incident AD also had a greater increase in NfL (b = 0.041, p = 0.027) and GFAP (b = 0.04, p = 0.006) than controls. Hispanics had a faster increase in NfL (b = 0.033, p = 0.002) and GFAP (b = 0.034, p<0.001), and Black participants had a faster increase in NfL (b = 0.028, p = 0.023), compared to Whites. Neither sex nor APOE ɛ4 genotype affected rates of biomarker changes.ConclusionLongitudinal change in plasma biomarkers may have clinical utility, since incident MCI and AD are accompanied by faster increases in P‐tau181, NfL, and GFAP, and a faster decrease in Aβ42/ Aβ40 ratio. The trajectories of AD biomarker change may also vary by race and ethnicity.

Evaluation of the association between circulatory markers of neuroinflammation and Alzheimer’s disease pathology

AbstractBackgroundIncreasing evidence suggests that neuroinflammation and astrogliosis have a prominent role in the spread of pathology and the development of cognitive impairment in Alzheimer’s disease (AD). Circulating plasma markers of neuroinflammation, such as the glial fibrillary acid protein (GFAP), have recently become available, and early observations suggest a robust association with brain pathology. Positron emission tomography (PET) is a molecular imaging technique that allows visualisation and quantification of AD pathology in vivo. The aim of this study was to evaluate the association between GFAP and AD pathology, and its interaction with cognitive decline.Method121 subjects from the Geneva Memory Centre underwent amyloid and tau PET, blood collection, and mini‐mental state examination (MMSE). Amyloid uptake was calculated as centiloid whereas tau was quantified as standardised uptake value ratio. Association of centiloid and tau with GFAP was assessed using a multivariate linear regression model, corrected for age, gender, and MMSE. Mediation analysis described the mediating effect of GFAP on the association between centiloid and tau. Ninety‐four subjects had a follow‐up MMSE after at least 12 months. Linear regression was used to assess the effect of GFAP on the annual rate of change of MMSE (corrected for centiloid, global tau, age, and gender). Mediation analysis was used to test whether the relationship between rate of MMSE change and tau could be explained by a mediation of GFAP.ResultThe mean (SD) age of the participants was 72.6 (7.6) years, and 61 of 121 subjects were men. GFAP was significantly associated with increased tau, but not with centiloid. GFAP partially mediated the effect of centiloid on global tau (mediated proportion = 14%, p = 0.03). The rate of MMSE change was significantly associated with GFAP, and global tau, but not with centiloid. Moreover, GFAP partially mediated the effect between global tau SUVR and change of MMSE scores (52%, p<0.01).ConclusionElevated GFAP is associated with tau. GFAP also partially explains the effect of amyloid pathology on tau accumulation and of tau pathology on subsequent cognitive decline. These results support neuroinflammation and astrogliosis as a relevant contributor to AD pathology, which can be monitored in blood.

Exploring the Utility of Biofluid‐Based Biomarkers in Early‐Onset Alzheimer’s Disease

AbstractBackgroundOne goal of the longitudinal early onset Alzheimer’s disease study (LEADS) is to define fluid biomarker characteristics of early‐onset Alzheimer’s disease (EOAD). In this mid‐study cross sectional analysis, participants have undergone clinical and cognitive assessments, magnetic resonance imaging (MRI), positron emission tomography (PET), lumbar puncture, and blood draws. There is limited data available concerning comprehensive analysis of fluid biomarkers in an EOAD population and this study represents first results from the mid‐study analysis of a large multi‐site cohort.MethodLEADS is an observational study with N = 371 subjects included in the mid‐study analysis (N = 165 with CSF and N = 324 with plasma biomarker data). CSF levels of Aβ1‐40, Aβ1‐42, tTau, pTau181, VILIP‐1, SNAP‐25, neurogranin (Ng), neurofilament light chain (NfL), and YKL‐40 were measured by immunoassay. Plasma levels of Aβ1‐40, Aβ1‐42, NfL, pTau231, and glial fibrillary acid protein (GFAP) were measured by immunoassay. Differences by diagnostic group and Spearman’s correlations with cognitive measures (MOCA, CDR‐SB, ADAS‐Cog) were evaluated for each fluid biomarker. Diagnostic accuracies were determined using area under the curve of receiver operating characteristics curve analysis which included APOE4 carrier status, age and sex in logistic regression models.ResultLevels of CSF Aβ42/40, pTau181, tTau, SNAP25, and Ng in the EOAD group were significantly different from both cognitively normal and early‐onset non‐AD dementia groups; CSF NfL, YKL‐40 and VILIP‐1 did not vary by diagnosis. The combination of APOE ε4 carrier status, age, sex and CSF Aβ42/40 and pTau181 (Figure 1A) or plasma Aβ42/40 and pTau231 (Figure 1B) separated the EOAD group from CN and EOnonAD with Area Under the ROC curves of 0.99 and 0.89 respectively. The diagnostic accuracies of plasma Aβ42/40 or pTau231 were 0.80 and 0.86 respectively. In the pooled analysis, all CSF biomarkers except SNAP25 were correlated with cognition (Figure 2A). Within the EOAD group only CSF Aβ42/40, NfL, Ng, and SNAP25 were correlated with at least one cognitive measure (Figure 2B).ConclusionThis study provides the first comprehensive analysis of fluid biomarkers in sporadic EOAD and will inform clinical trial designs that incorporate fluid biomarkers in patient selection, or as biomarker endpoints.

Diagnostic of Novel Plasma Biomarkers in Controls, SCD and MCI Subjects

AbstractBackgroundAlzheimer’s disease (AD) is the most common cause of dementia, and a challenging disease for the development of plasma biomarkers. Blood samples are the most easily collectable samples for medical diagnosis. This study evaluates the potential of plasma biomarkers in identifying early stages of AD.Method189 participants were recruited at the NYU Alzheimer Disease Research Center. This cohort includes n = 75 with normal cognition (NL), n = 77 with subjective cognitive decline (SCD), n = 37 with mild cognitive impairment (MCI). Comprehensive neuropsychological and magnetic resonance imaging evaluations were conducted for all patients. Plasma biomarkers assays (total tau [t‐tau], neurofilament light [NfL], glial fibrillary acid protein [GFAP], ubiquitin carboxyl‐terminal hydrolase L1 [UCH‐L1], Aβ1‐42, Aβ1‐40 and pTau181) were measured using the SIMOA SR‐X, a novel technology that employs highly sensitive immunoassays with a limit of detection (LOD) under 100 fg/ml.ResultThe levels of NfL, t‐Tau, GFAP and UCH‐L1 were measured using the Neurology 4‐plex A. NfL levels showed a significant difference between NL and SCD (one tailed t‐ test p = 0.0459). GFAP showed statistically significant differences between NL and MCI, (one tailed t‐test p = 0.0369). Aβ1‐42 showed a significant difference between SCD and MCI (one tailed t‐test p = 0.0493). pTau181 levels showed a significant difference between NL, SCD and NL, MCI (p = 0.0447 and p = 0.0439, respectively). The ratio of pTau181/Aβ1‐42 shows a significant difference between NL and MCI (one tailed t‐test p = 0.0187). Correlation of these biomarkers with brain imaging and cognitive measures is underway.ConclusionBiomarker levels of NfL, GFAP, Aβ1‐42, pTau181 and Ratio pTau181/Aβ1‐42 in plasma samples showed several significant differences between the three groups of subjects. Plasma biomarkers can be useful for the diagnosis of AD related pathology at early stages.

Involvement of interferon gamma signaling in spinal trigeminal caudal subnucleus astrocyte in orofacial neuropathic pain in rats with infraorbital nerve injury.

Background: Trigeminal nerve injury causes orofacial pain that can interfere with activities of daily life. However, the underlying mechanism remains unknown, and the appropriate treatment has not been established yet. This study aimed to examine the involvement of interferon gamma (IFN-γ) signaling in the spinal trigeminal caudal subnucleus (Vc) in orofacial neuropathic pain. Methods: Infraorbital nerve (ION) injury (IONI) was performed in rats by partial ION ligation. The head-withdrawal reflex threshold (HWT) to mechanical stimulation of the whisker pad skin was measured in IONI or sham rats, as well as following a continuous intracisterna magna administration of IFN-γ and a mixture of IFN-γ and fluorocitrate (inhibitor of astrocytes activation) in naïve rats, or an IFN-γ antagonist in IONI rats. The IFN-γ receptor immunohistochemistry and IFN-γ Western blotting were analyzed in the Vc after IONI or sham treatment. The glial fibrillary acid protein (GFAP) immunohistochemistry and Western blotting were also analyzed after administration of IFN-γ and the mixture of IFN-γ and fluorocitrate. Moreover, the change in single neuronal activity in the Vc was examined in the IONI, sham, and IONI group administered IFN-γ antagonist. Results: The HWT decreased after IONI. The IFN-γ and IFN-γ receptor were upregulated after IONI, and the IFN-γ receptor was expressed in Vc astrocytes. IFN-γ administration decreased the HWT, whereas the mixture of IFN-γ and fluorocitrate recovered the decrement of HWT. IFN-γ administration upregulated GFAP expression, while the mixture of IFN-γ and fluorocitrate recovered the upregulation of GFAP expression. IONI significantly enhanced the neuronal activity of the mechanical-evoked responses, and administration of an IFN-γ antagonist significantly inhibited these enhancements. Conclusions: IFN-γ signaling through the receptor in astrocytes is a key mechanism underlying orofacial neuropathic pain associated with trigeminal nerve injury. These findings will aid in the development of therapeutics for orofacial neuropathic pain.

Associations between depressive symptoms, glial fibrillary acid protein, and cognitive decline in a population‐based study

AbstractBackgroundDepressive symptoms are a known risk factor for dementia, and higher concentrations of glial fibrillary acid protein (GFAP) is associated with a faster rate of cognitive decline. However, it is unknown whether the two risk factors increase the risk of cognitive decline additively.MethodThis investigation is based on 1,169 participants from the Chicago Health and Aging Project (CHAP), a population‐based cohort study, who completed at least two cognitive performance assessments with baseline serum GFAP measurement. Depressive symptoms were determined utilizing a modified version of the Center for Epidemiologic Studies‐Depression Scale. A composite global cognitive function score was calculated using cognitive performance testing. Linear mixed effects regression models were conducted to examine the association of depressive symptoms and GFAP concentrations on baseline global cognitive function and the annual rate of cognitive decline. Regression models also adjusted for age, race, sex, education, chronic medical conditions, and their interactions with time.ResultOur study sample consisted of 60% African American participants and 63% female participants and had an average age of 77 (SD = 6.0) years. In our sample, 21% had few depressive symptoms (0‐2), and the remaining 79% had more depressive symptoms (3‐10). We found a statistically significant interaction between depressive symptoms and GFAP (β = ‐111 (SE = .039), p = .005) on global cognitive function. Stratified analysis showed that the associations between the log of GFAP and global cognitive function were statistically significant for participants with few (0‐2) depressive symptoms (β = ‐.223 (SE = .087), p = .010) and more (3‐10) depressive symptoms (β = ‐.781 (SE = .198), p = .000). Statistically significant associations were also observed between the log of GFAP and global cognitive decline for participants with few (β = ‐.069 (SE = .017), p = .000) and more (β = ‐.100 (SE = .040), p = .012) depressive symptoms.ConclusionOur findings show additive effects of depressive symptoms in the association between the log of GFAP with baseline global cognitive function and rate of cognitive decline. Prevention and treatment of depression in old age can significantly impact the risk of progressive cognitive decline, especially among individuals with higher concentrations of GFAP.

Mechanisms behind changes of neurodegeneration biomarkers in plasma induced by sleep deprivation.

Acute sleep deprivation has been shown to affect cerebrospinal fluid and plasma concentrations of biomarkers associated with neurodegeneration, though the mechanistic underpinnings remain unknown. This study compared individuals who, for one night, were either subject to total sleep deprivation or free sleep, (i) examining plasma concentrations of neurodegeneration biomarkers the morning after sleep deprivation or free sleep and (ii) determining how overnight changes in biomarkers plasma concentrations correlate with indices of meningeal lymphatic and glymphatic clearance functions. Plasma concentrations of amyloid-β 40 and 42, phosphorylated tau peptide 181, glial fibrillary acid protein and neurofilament light were measured longitudinally in subjects who from Day 1 to Day 2 either underwent total sleep deprivation (n = 7) or were allowed free sleep (n = 21). The magnetic resonance imaging contrast agent gadobutrol was injected intrathecally, serving as a cerebrospinal fluid tracer. Population pharmacokinetic model parameters of gadobutrol cerebrospinal fluid-to-blood clearance were utilized as a proxy of meningeal lymphatic clearance capacity and intrathecal contrast-enhanced magnetic resonance imaging as a proxy of glymphatic function. After one night of acute sleep deprivation, the plasma concentrations of amyloid-β 40 and 42 were reduced, but not the ratio, and concentrations of the other biomarkers were unchanged. The overnight change in amyloid-β 40 and 42 plasma concentrations in the sleep group correlated significantly with indices of meningeal lymphatic clearance capacity, while this was not seen for the other neurodegeneration biomarkers. However, overnight change in plasma concentrations of amyloid-β 40 and 42 did not correlate with the glymphatic marker. On the other hand, the overnight change in plasma concentration of phosphorylated tau peptide 181 correlated significantly with the marker of glymphatic function in the sleep deprivation group but not in the sleep group. The present data add to the evidence of the role of sleep and sleep deprivation on plasma neurodegeneration concentrations; however, the various neurodegeneration biomarkers respond differently with different mechanisms behind sleep-induced alterations in amyloid-β and tau plasma concentrations. Clearance capacity of meningeal lymphatics seems more important for sleep-induced changes in amyloid-β 40 and 42 plasma concentrations, while glymphatic function seems most important for change in plasma concentration of phosphorylated tau peptide 181 during sleep deprivation. Altogether, the present data highlight diverse mechanisms behind sleep-induced effects on concentrations of plasma neurodegeneration biomarkers.

Mesoscopic Assessment of Microstructure in Glioblastomas and Metastases by Merging Advanced Diffusion Imaging with Immunohistopathology.

Glioblastomas and metastases are the most common malignant intra-axial brain tumors in adults and can be difficult to distinguish on conventional MR imaging due to similar imaging features. We used advanced diffusion techniques and structural histopathology to distinguish these tumor entities on the basis of microstructural axonal and fibrillar signatures in the contrast-enhancing tumor component. Contrast-enhancing tumor components were analyzed in 22 glioblastomas and 21 brain metastases on 3T MR imaging using DTI-fractional anisotropy, neurite orientation dispersion and density imaging-orientation dispersion, and diffusion microstructural imaging-micro-fractional anisotropy. Available histopathologic specimens (10 glioblastomas and 9 metastases) were assessed for the presence of axonal structures and scored using 4-level scales for Bielschowsky staining (0: no axonal structures, 1: minimal axonal fragments preserved, 2: decreased axonal density, 3: no axonal loss) and glial fibrillary acid protein expression (0: no glial fibrillary acid protein positivity, 1: limited expression, 2: equivalent to surrounding parenchyma, 3: increased expression). When we compared glioblastomas and metastases, fractional anisotropy was significantly increased and orientation dispersion was decreased in glioblastomas (each P < .001), with a significant shift toward increased glial fibrillary acid protein and Bielschowsky scores. Positive associations of fractional anisotropy and negative associations of orientation dispersion with glial fibrillary acid protein and Bielschowsky scores were revealed, whereas no association between micro-fractional anisotropy with glial fibrillary acid protein and Bielschowsky scores was detected. Receiver operating characteristic curves revealed high predictive values of both fractional anisotropy (area under the curve = 0.8463) and orientation dispersion (area under the curve = 0.8398) regarding the presence of a glioblastoma. Diffusion imaging fractional anisotropy and orientation dispersion metrics correlated with histopathologic markers of directionality and may serve as imaging biomarkers in contrast-enhancing tumor components.

Microscopic anatomy of the subcommissural organ in the brain of the adult greater cane rat (Rodentia: Thryonomyidae).

The subcommissural organ (SCO) is a well-developed gland present in the brain of vertebrates. The SCO secretes glycoproteins into the circulating cerebrospinal fluid and these assemble to form Reissner's fibre. It also plays an important function in neurogenesis and axonal guidance during embryogenesis. This study delves into the microscopic anatomy of the SCO in the adult greater cane rat (GCR), shedding light on its histoarchitectural characteristics. By utilizing histological techniques and microscopic analysis, we investigated the SCO's location and cellular composition within the brain of adult GCR. Our findings showed that the SCO in this species is located ventrally to the posterior commissure (PC) and dorsally to the third ventricle. The SCO consists of specialized ependymal or nuclear cell layer and apical processes lining the third ventricle. Moreover, the SCO's proximity to the PC and the third ventricle highlights its strategic position within the brain's ventricular system. With immunohistochemical analyses, the SCO cells expressed glial fibrillary protein when immunolabelled with Glial fibrillary acid protein (GFAP) antibody, a marker for astrocytes/astrocytic-like cells. Few microglia-like cells were immuno-positive for Ionized calcium-binding adapter molecule 1 (Iba1) antibody, that are existing within the SCO. However, the SCO in the GCR showed a negative immunostaining to NeuN antibody. This study contributes to our understanding of the microscopic anatomy of the SCO in a lesser-studied mammalian species. Further research into the SCO's functional significance especially during development in the GCR, may hold promise for more insights into neurological health and pathology.

Testosterone upregulates glial cell line-derived neurotrophic factor (GDNF) and promotes neuroinflammation to enhance glioma cell survival and proliferation

BackgroundTestosterone contributes to male organism development, such as bone density, muscle development, and fat repartition. Estrogen (derived from testosterone) also contributes to female reproductive system development. Here, we investigated the effect of testosterone on glioma cells and brain neuron inflammation essential for cancer development and progression.MethodsThe human astrocyte and glioma cell lines were treated with 6 ng/ml exogenous testosterone in vitro. We performed cell counting kit-8, transwell, and wound healing assays to determine the effect of testosterone on glioma cell proliferation, migration, and invasion. The glioma cells were injected into the xenograft and treated with 5 µl concentrated testosterone. Transcriptional suppression of glial cell line-derived neurotrophic factor (GDNF) was performed to evaluate brain neuron inflammation and survival. The tumor tissues were assessed by hematoxylin–eosin staining and immunohistochemistry.ResultsTestosterone upregulates GDNF to stimulate proliferation, migration, and invasion of glioma cells. Pathologically, the augmentation of GDNF and cyclophilin A contributed to neuroprotection when treated with testosterone. Our investigation showed that testosterone contributes to brain neuron and astrocyte inflammation through the upregulation of nuclear factor erythroid 2-related factor 2 (NRF2), glial fibrillary acid protein (GFAP), and sirtuin 5 (SIRT5), resulting in pro-inflammatory macrophages recruitments into the neural microenvironment. Mechanically, testosterone treatment regulates GDNF translocation from the glioma cells and astrocyte nuclei to the cytoplasm.ConclusionTestosterone upregulates GDNF in glioma cells and astrocytes essential for microglial proliferation, migration, and invasion. Testosterone contributes to brain tumor growth via GDNF and inflammation.Graphical The contribution of testosterone, macrophages, and astrocytes, in old neuron rescue, survival, and proliferation. During brain neuron inflammation, the organism activates and stimulates the neuron rescue through the enrichment of the old neuron microenvironment with growth factors such as GDNF, BDNF, SOX1/2, and MAPK secreted by the surrounding neurons and glial cells to maintain the damaged neuron by inflammation alive even if the axon is dead. The immune response also contributes to brain cell survival through the secretion of proinflammatory cytokines, resulting in inflammation maintenance. The rescued old neuron interaction with infiltrated macrophages contributes to angiogenesis to supplement the old neuron with more nutrients leading to metabolism activation and surrounding cell uncontrollable cell growth.

GFAP serves as a structural element of tunneling nanotubes between glioblastoma cells and could play a role in the intercellular transfer of mitochondria.

Tunneling nanotubes (TNTs) are long F-actin-positive plasma membrane bridges connecting distant cells, allowing the intercellular transfer of cellular cargoes, and are found to be involved in glioblastoma (GBM) intercellular crosstalk. Glial fibrillary acid protein (GFAP) is a key intermediate filament protein of glial cells involved in cytoskeleton remodeling and linked to GBM progression. Whether GFAP plays a role in TNT structure and function in GBM is unknown. Here, analyzing F-actin and GFAP localization by laser-scan confocal microscopy followed by 3D reconstruction (3D-LSCM) and mitochondria dynamic by live-cell time-lapse fluorescence microscopy, we show the presence of GFAP in TNTs containing functional mitochondria connecting distant human GBM cells. Taking advantage of super-resolution 3D-LSCM, we show the presence of GFAP-positive TNT-like structures in resected human GBM as well. Using H2O2 or the pro-apoptotic toxin staurosporine (STS), we show that GFAP-positive TNTs strongly increase during oxidative stress and apoptosis in the GBM cell line. Culturing GBM cells with STS-treated GBM cells, we show that STS triggers the formation of GFAP-positive TNTs between them. Finally, we provide evidence that mitochondria co-localize with GFAP at the tip of close-ended GFAP-positive TNTs and inside receiving STS-GBM cells. Summarizing, here we found that GFAP is a structural component of TNTs generated by GBM cells, that GFAP-positive TNTs are upregulated in response to oxidative stress and pro-apoptotic stress, and that GFAP interacts with mitochondria during the intercellular transfer. These findings contribute to elucidate the molecular structure of TNTs generated by GBM cells, highlighting the structural role of GFAP in TNTs and suggesting a functional role of this intermediate filament component in the intercellular mitochondria transfer between GBM cells in response to pro-apoptotic stimuli.

Immunohistochemical Characteristics of Glial Cells Reorganization in Neocortex as a Result of Severe Traumatic Brain Injury

The aim was to study the reorganization of gliocytes and GFAP expression of the rat neocortex using histological, immunomorphological and morphometric methods (in particular fractal analysis) after severe traumatic brain injury (STBI).Material and methods. Modeling of STBI was performed using a patented device with a shock mechanism based on the principle of transferring kinetic energy of a falling cylindrical load. During the experiment, the rats were divided into 2 groups: main (n=30) and control (intact, n=6). The brain of rats was extracted after 1, 3, 7, 14 and 30 days after heavy traumatic brain injury. The assessment of the glia of layers III and V of the sensorimotor cortex (SMC) was carried out by analyzing histological preparations of the rat brain (stained with hematoxylin-eosin and thionin) using light microscopy, immunohistochemical reaction to glial fibrillary acid protein (GFAP) and morphometric processing in the Image 1.53 program. Fractal analysis was performed using the FracLac 2.5 plugin to evaluate the astrocyte network. Statistical processing of the data obtained was carried out using nonparametric methods of information processing of the application package Statistica 10.0 programs.Results. Throughout the post-traumatic period, changes in the SMC neurons were accompanied by an increase in the numerical density of gliocytes. The maximum peak of the microglyocyte content was higher already 1 day after HTBI: by 13.4% in layer III of the SMC and by 24.2% in layer V of the SMC. The minimum indicator of the numerical density of oligodendrocytes was observed 30 days after HTBI: in layer III of the SMC by 32.2%, and in layer V of the SMC – 43.9%. 1 day after the injury, there was a statistically significant increase in the numerical density of astrocytes in layers III and V of the SMC above the control values. During 30 days, the content of gliocytes decreased: in layer III of the SMC – 23%, and in layer V of the SMC – 26.8%. When GFAP was expressed, protoplasmic and fibrous astrocytes differing in body size and length of processes were found in layer III and V of the SMC. The indicators characterizing the appendages as a spatial object changed statistically significantly in comparison with the control and in the post-traumatic period between terms. The fractal dimension changed the most and a high lacunarity was observed in layer III of the SMC. For 14 days, the indicator was less than the reference value, and by this time it was already recovering in layer V of the SMC. Taken together, all this indicated a higher reactive reorganization of the processes of astrocytes of the small cell layer of the III SMC.Conclusion. After a heavy traumatic brain injury, a heterogeneous reorganization of the neuroglial complex was observed in the sensorimotor cortex (SMC). The detected changes in the numerical density of gliocytes in layers III and V of the SMC throughout the post-traumatic period were heterochronous. Morphometric analysis data confirmed the spatial reorganization of astrocytes, active proliferation of microglyocytes and oligodendrocytes – changes that contribute to the compensatory protection of the structures of the nervous tissue of the SMC in the post-traumatic period.

Index of consciousness monitoring during general anesthesia may effectively enhance rehabilitation in elderly patients undergoing laparoscopic urological surgery: a randomized controlled clinical trial

BackgroundBased on electroencephalogram (EEG) analysis, index of consciousness (IoC) monitoring is a new technique for monitoring anesthesia depth. IoC is divided into IoC1 (depth of sedation) and IoC2 (depth of analgesia). The potential for concurrent monitoring of IoC1 and IoC2 to expedite postoperative convalescence remains to be elucidated. We investigated whether combined monitoring of IoC1 and IoC2 can effectively enhances postoperative recovery compared with bispectral index (BIS) in elderly patients undergoing laparoscopic urological surgery under general anesthesia.MethodsIn this prospective, controlled, double-blinded trail, 120 patients aged 65 years or older were arbitrarily assigned to either the IoC group or the control group (BIS monitoring). All patients underwent blood gas analysis at T1 (before anesthesia induction) and T2 (the end of operation). The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were administered to all patients at T0 (1 day before surgery) and T4 (7 days after surgery). Serum concentrations of C-reactive protein (CRP) and glial fibrillary acid protein (GFAP) were assessed at T1, T2, and T3 (24 h after surgery). Postoperative complications and the duration of hospitalization were subjected to comparative evaluation.ResultsThe incidence of postoperative cognitive dysfunction (POCD) was notably lower in the IoC group (10%) than in the control group (31.7%) (P = 0.003). Postoperative serum CRP and GFAP concentrations exhibited significant differences at time points T2 (CRP: P = 0.000; GFAP: P = 0.000) and T3 (CRP: P = 0.003; GFAP: P = 0.008). Postoperative blood glucose levels (P = 0.000) and the overall rate of complications (P = 0.037) were significantly lower in Group IoC than in Group control.ConclusionThe employment of IoC monitoring for the management of elderly surgical patients can accelerate postoperative convalescence by mitigating intraoperative stress and reducing peripheral and central inflammatory injury.Trial registrationChinese Clinical Trial Registry Identifier: ChiCTR1900025241 (17/08/2019).

Diclofenac sodium and dexamethasone co-therapy restores brain neuron-specific enolase (NSE), S-100 Beta and glial fibrillary acid protein (GFAP) proteins in experimental rat's model: A possible inhibition of P-glycoprotein.

Non-steroidal anti-inflammatory drugs decrease pain and fever while corticosteroids regulate inflammation and immune response, both are prescribed to reduce inflammation and control pain. The present study aimed to study the effects of their monotherapy and co-administration on the brain tissue structure of experimental rats. P-glycoprotein (PGP), a transporter membrane protein, plays an important role in various physiological and physio-pathological conditions, drug-drug and drug-food interactions, and multi-drug resistance. Male rats were divided into four groups and received normal saline, dexamethasone, diclofenac sodium and their dual therapy respectively, then after one-month rats were sacrificed and brain tissues proceeded for hematoxylin and eosin staining to study their histopathology and immunohistochemically staining of NSE, S100-B and GFAP biomarkers were performed. Additionally, in silico molecular docking studies were conducted to elucidate interactions between PGP and used compounds. Resultsshowed that dexamethasone or diclofenac sodium treatments showed abnormalities like edema, neuronal vacuoles, astrocytes hyperplasia and microglial cells with positive reaction to NSE, S100 and GFAP antibodies while the dual therapy displayed less edema and other signs of damage with negative and weak positive staining of NSE, S100 and GFAP antibodies respectively. The molecular docking showed that there were different affinities toward the involved PGP active site. These interaction results were great with Dexamethasone -9.6 kcal/mol forming hydrophobic interactions with the highest affinity when compared with Diclofenac sodium which gave -8.4 kcal/mol. In conclusion, the side effects of the two types of anti-inflammatory drugs may be minimized through their interactions. However, Molecular Dynamic Simulations studies are required to explain the exact dynamic behaviors and protein-ligand stability.

Biochemical markers of neurodegeneration in patients with cerebral small vessel disease and Alzheimer's disease

Introduction. Cerebral small vessel disease (CSVD) as well as the Alzheimer's disease (AD) and their comorbidities are the most common causes of cognitive impairments (CIs).&#x0D; Objective: to evaluate the predictive power of the biochemical neurodegeneration markers in patients with CSVD and AD.&#x0D; Materials and methods. We assessed the following neurodegeneration markers in 68 patients with CSVD (61.0 8.6 years; 60.3% males), 17 patients with AD (65.2 8.3 years; 35.3% males), and 26 healthy volunteers (59.9 6.7 years; 38.5% males): neuron-specific enolase (NSE), glial fibrillary acid protein (GFAP), neurofilament light polypeptide (NEFL) in blood (for all patients) and in cerebrospinal fluid (CSF; in patients with CSVD and AD). We assessed the predictive power of those markers with ROC analysis.&#x0D; Results. As compared to the control group, serum GFAP in patients with CSVD showed its predictive power at 0.155 ng/ml (sensitivity 74%; specificity 70%). Serum NEFL 0.0185 ng/ml (sensitivity 82%; specificity 96%) and NSE 4.95 g/ml (sensitivity 77%; specificity 71%) showed their predictive power in patients with AD. CSF GFAP 1.03 ng/ml (sensitivity 84%; specificity 88%), CSF NSE 19.10 g/ml (sensitivity 88%; specificity 91%), serum NEFL 0.021 ng/ml (sensitivity 71%; specificity 76%), serum NSE /CSF NSE ratio 0.273 ng/ml (sensitivity 87%; specificity 88%) help differentiate CSVD from AD.&#x0D; Conclusions. We found that serum GFAP can be a useful diagnostic marker in patients with CSVD, while serum NEFL and serum NSE can help identify the AD. In addition, CSF GFAP and CSF NSE as well as serum NEFL and serum NSE/CSF NSE can help differentiate CSVD from AD. We can use those markers in clinical and research practice to identify the vascular and neurodegenerative causes of CIs and their comorbidities, which is of a great importance in developing specific treatment and predicting the course of the disease.

Neurobiomarker and body temperature responses to recreational marathon running

ObjectivesTo assess how biomarkers indicating central nervous system insult (neurobiomarkers) vary in peripheral blood with exertional-heat stress from prolonged endurance exercise. DesignObservational study of changes in neuron specific enolase (NSE), S100 calcium-binding protein B (S100β), Glial Fibrillary Acid Protein (GFAP) and Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) at Brighton Marathon 2022. MethodsIn 38 marathoners with in-race core temperature (Tc) monitoring, exposure (High, Intermediate or Low) was classified by cumulative hyperthermia – calculated as area under curve of Time × Tc > 38 °C – and also by running duration (finishing time). Blood was sampled for neurobiomarkers, cortisol and fluid-regulatory stress surrogates, including copeptin and creatinine (at rested baseline; within 30 min of finishing; and at 24 h). ResultsFinishing in 236 ± 40 min, runners showed stable GFAP and UCH-L1 across the marathon and next-day. Significant (P < 0.05) increases from baseline were shown post-marathon and at 24 h for S100β (8.52 [3.65, 22.95] vs 39.0 [26.48, 52.33] vs 80.3 [49.1, 99.7] ng·L−1) and post-marathon only for NSE (3.73 [3.30, 4.32] vs 4.85 [4.45, 5.80] μg·L−1, P < 0.0001). Whilst differential response to hyperthermia was observed for cortisol, copeptin and creatinine, neurobiomarker responses did not vary. Post-marathon, only NSE differed by exercise duration (High vs Low, 5.81 ± 1.77 vs. 4.69 ± 0.73 μg·L−1, adjusted P = 0.0358). ConclusionsSuccessful marathon performance did not associate with evidence for substantial neuronal insult. To account for variation in neurobiomarkers with prolonged endurance exercise, factors additional to hyperthermia, such as exercise duration and intensity, should be further investigated.

Early Alzheimer's Disease Screening Approach Using Plasma Biomarkers.

Alzheimer's disease (AD) is the most prevalent dementia, but it shows similar initial symptoms to other neurocognitive diseases (Lewy body disease (LBD) and frontotemporal dementia (FTD)). Thus, the identification of reliable AD plasma biomarkers is required. The aim of this work is to evaluate the use of a few plasma biomarkers to develop an early and specific AD screening method. Plasma p-Tau181, neurofilament light (NfL), and glial fibrillary acid protein (GFAP) were determined by Single Molecule Assay (SIMOA® Quanterix, Billerica, MA, USA) in patients with mild cognitive impairment due to AD (MCI-AD, n = 50), AD dementia (n = 10), FTD (n = 20), LBD (n = 5), and subjective cognitive impairment (SCI (n = 21)). Plasma p-Tau181 and GFAP showed the highest levels in AD dementia, and significant correlations with clinical AD characteristics; meanwhile, NfL showed the highest levels in FTD, but no significant correlations with AD. The partial least squares (PLS) diagnosis model developed between the AD and SCI groups showed good accuracy with a receiver operating characteristic (ROC) area under curve (AUC) of 0.935 (CI 95% 0.87-0.98), sensitivity of 86%, and specificity of 88%. In a first screen, NfL plasma levels could identify FTD patients among subjects with cognitive impairment. Then, the developed PLS model including p-Tau181 and GFAP levels could identify AD patients, constituting a simple, early, and specific diagnosis approach.