Mean Glial Fibrillary Acidic Protein Research Articles

Using Plasma NfL and GFAP to Monitor Response to Anti-CD20 Treatment in MS (P1-3.010)

<h3>Objective:</h3> To compare changes in plasma concentrations of Neurofilament light (NfL) and Glial Fibrillary Acidic Protein (GFAP) in individuals with relapsing multiple sclerosis (RMS) vs progressive multiple sclerosis (PMS), treated with anti-CD20 immunotherapy (rituximab or ocrelizumab) <h3>Background:</h3> Blood biomarkers, especially NfL, can augment clinical and radiographic data in MS treatment monitoring. Few studies have investigated longitudinal change in NfL or GFAP in PMS patients taking anti-CD20s or compared changes in these biomarkers between RMS and PMS. <h3>Design/Methods:</h3> Subjects were selected by MS diagnosis, anti-CD20 treatment for at least 6 months, and presence of multiple blood samples in our Center’s Biorepository. Demographic/clinical information was extracted by chart review. SIMOA plasma assays of NfL and GFAP were conducted at baseline and follow-up (between 3 and 12 months) on Quanterix SR-X. Biomarker concentrations were log transformed. Summary statistics and longitudinal regression analyses, correcting for age, were generated. <h3>Results:</h3> 37 subjects and 67 samples were analyzed (n=7 had no follow-up samples between 3 and 12 months). 64.9% were female. RMS (n=19) had mean(SD) age 38.7(9.2). PMS (n=18) had mean age 56.1(10.4). Age-adjusted mean concentrations of NfL and GFAP did not differ significantly between RMS and PMS at baseline. Geometric mean NfL declined between baseline (6.8, 95%CI 4.2–11.0) and follow-up (4.9, 95%CI 3.3–7.3) in RMS but stayed stable in PMS. Geometric mean GFAP increased between baseline (52.4, 95%CI 35.2–77.9) and follow-up (60.8, 95%CI 40.4–91.4) in PMS but stayed stable in RMS. The changes for both NfL and GFAP differed statistically significantly between MS types. <h3>Conclusions:</h3> With anti-CD20 treatment, plasma NfL levels decreased in RMS by 27.6% while staying stable in PMS; GFAP levels increased in PMS by 16% while remaining stable in RMS. Results correlate with clinical evidence showing greater benefit of anti-CD20 immunotherapy in RMS compared to PMS. Future studies will include more subjects, longer observation, and different immunotherapies. <b>Disclosure:</b> Dr. Gross has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for AP Expert Group. The institution of Stefan Sillau has received research support from Alzheimer’s Association. The institution of Stefan Sillau has received research support from Hewitt Family Foundation; State of Colorado. The institution of Stefan Sillau has received research support from PCORI. The institution of Stefan Sillau has received research support from NINR. The institution of Stefan Sillau has received research support from Michael J. Fox Foundation. The institution of Stefan Sillau has received research support from Department of Defense. The institution of Stefan Sillau has received research support from Colorado Department of Public Health and Environment. The institution of Stefan Sillau has received research support from Benign Essential Blepharospasm Research Foundation. Stefan Sillau has a non-compensated relationship as a Statistician with Novartis that is relevant to AAN interests or activities. Stefan Sillau has a non-compensated relationship as a Statistician with Biogen that is relevant to AAN interests or activities. Sean Selva has nothing to disclose. Mrs. Ritchie has nothing to disclose.

Combining impact monitoring mouthguards and blood biomarkers to monitor head impacts among Muay Thai athletes – A case study

ObjectiveTo investigate the relationship between head impact characteristics and the levels of blood biomarkers associated with brain injury, neurofilament light (NfL) and glial fibrillary acidic protein (GFAP). MethodsFour elite amateur Muay Thai athletes were equipped with impact monitoring mouthguards, collecting linear and rotational acceleration data during a period of eight weeks. Capillary blood samples were collected after each period of sparring sessions to analyse the levels of NfL and GFAP. ResultsOn a group level, mean GFAP levels were negatively correlated to mean impacts per session (p ​< ​0.05). Two athletes had significant correlations between head impact characteristics and the levels of NfL and/or GFAP. ConclusionsThe results indicate that NfL and GFAP might responded differently to linear and rotational accelerations and/or that the effect of different types of accelerations on brain tissue integrity is individual. The methods used could be useful to monitor brain health in different impacts sports.

Glial fibrillary acidic protein level on admission can predict severe traumatic brain injury in patients with severe multiple trauma: A single-center retrospective observational study.

This study aimed to clarify whether the glial fibrillary acidic protein (GFAP) and soluble protein-100β (S100β) can predict severe traumatic brain injury (TBI) in patients with severe multiple trauma. This is a single-center retrospective observational study of 179 patients with severe multiple trauma. The GFAP and S100β were measured upon patient arrival at the hospital. We divided the patients into the severe TBI group (with a Traumatic Coma Data Bank classification of ≥III), the non-severe TBI group (non-TBI group [absence of abnormality on the computed tomography scan and extracranial injury], and the mild to moderate TBI group [TCDB classification I and II]). We compared biomarker levels between the two groups and then evaluated the accuracy of predicting severe TBI using a receiver operating characteristic curve. A total of 41 patients had severe TBI, and 138 had non-severe TBI. Mean GFAP levels were significantly higher in the severe TBI group (median, 6000pg/mL; interquartile range [IQR], 651-15,548pg/mL) than in the non-severe TBI group (median, 149pg/mL; IQR, 0-695pg/mL) (p<0.0001). In contrast, there was no significant difference in S100β levels between the severe TBI group (median, 64pg/mL; IQR, 0-536pg/mL) and non-severe TBI group (median, 117pg/mL; IQR, 0-403pg/mL) (p=0.637). The area under the receiver operating characteristic curve was 0.810 (p<0.0001) for GFAP and 0.476 (p=0.908) for S100β. For the GFAP, the optimal cutoff value for detecting severe TBI was 947pg/mL (sensitivity, 75.6%; specificity, 78.3%). In patients with severe multiple trauma, the GFAP level at hospital arrival could predict severe TBI, whereas the S100β level was not a useful predictor.

Astrogliosis and episodic memory in late life: higher GFAP is related to worse memory and white matter microstructure in healthy aging and Alzheimer's disease

Astrocytes play a formative role in memory consolidation during physiological conditions; when dysregulated, astrocytes release glial fibrillary acidic protein (GFAP), which has been linked with negative memory outcomes in animal studies. We examined the association between blood GFAP, memory, and white matter (WM) integrity, accounting for blood markers of AD pathology (i.e., Aβ42) and neurodegeneration (i.e., total tau; neurofilament light chain) in 114 older adults (asymptomatic, n = 69; MCI/AD dementia, n = 45). Higher levels of GFAP were associated with lower memory scores (p < 0.0001), such that for 1 SD increase in mean GFAP values, the memory composite score decreased on average by 0.49 (Standard error = 0.071). These results remained significant after controlling for diagnostic status and AD-related blood biomarkers. Higher GFAP was also related to lower WM integrity in regions vulnerable to AD pathology; however, WM integrity did not account for the association between GFAP and memory. Study findings suggest that higher blood levels of a marker of astrogliosis may reflect impoverished memory functions and white matter health, independent of markers of amyloid or neurodegeneration.

Hepatoprotective Effect of Amygdalin (Vit B17) Against Phenolphthalein Induced liver injury; involvement of Glial fibrillary acidic protein (GFAP)

BackgroundPhenolphthalein (PTH) is an odorless and colorless chemical of laxative action and multiple side effects referred mostly to the production of free . It is primarily metabolized in the liver, hence its main adverse effects occur. Amygdalin (Vit B17) have antifibrotic, antiinflammatory and antitumor activities. The histopathological and functional changes in the liver together with the postulated protective hepatoprotective effect of Amygdalin were investigated in this study. Glial fibrillary acidic protein (GFAP) was considered as a marker of liver pathological changes.Material and methods30 adult male albino rats were divided into 3 groups. Group I was the control, group II received PTH alone and group III received both PTH and Amygdalin. At day 21, the levels of serum GFAP, total protein, total bilirubin and the activities of AST and ALT and liver hydroxyproline were estimated. The liver tissue samples were examined H&amp;E, Masson’s trichrome and anti‐GFAP immunoreactive stains, and electron microscopic examination.ResultsThe liver enzymes, total bilirubin, hydroxyproline, and serum GFAP were significantly increased in group II compared with the control and in group III compared to group II. The total proteins were significantly decreased in group II in comparison to the controls and highly significantly increased in group III compared to group II. Group II showed disturbed hepatic architecture with extensive congestion, degeneration with inflammatory cell infiltration and marked collagen deposition. Group III showed preserved hepatic parenchyma and scanty inflammatory cells infiltration with decreased collagen. Group II had strong and diffuse immunoexpression and group III liver tissues were similar to the controls. The mean area percentage of GFAP immune staining showed a highly significant increased immunopositivity in group II when compared to the group I and a significant decsrease in group III compared to group II. The ultrastructure of hepatic stellate cells of group II showed dilated rough endoplasmic reticulum and loss of lipid droplets. Group III were similar to the controls.ConclusionAmygdalin treatment had a hepatoprotective effect against PTH induced liver injury and fibrosis and GFAP level could be a predictor for HSCs activation.Graphical AbstractFigure 1GFAP immune staining of the liver section of the control group (A) showing positive staining of the stellate cell and the endothelium of the sinusoids. The endothelium of the central veins is negatively stained. B: the PTH group showing strong and diffuse immunoexpression mostly perisinusoidal. C: The PTH‐Amg. group showed less marked dye expression. D: Diagram of the mean GFAP stained area percentage of the 3 animal groupsFigure 2

Glial Fibrillary Acidic Protein Serum Level as a Predictor of Clinical Outcome in Ischemic Stroke.

BACKGROUND:Glial Fibrillary Acidic Protein (GFAP) is a protein produced by astrocytes in response to brain injury, which then penetrates the cerebrospinal fluid and the blood stream.AIM:We sought to determine whether GFAP serum level in acute ischemic stroke could predict clinical outcome.METHODS:As much as 64 patients with first-ever ischemic stroke had their GFAP serum level measured at 72 hours after onset. The National Institute of Health Stroke Scale (NIHSS) was assessed during the 72 hours of onset, the seventh day, and followed up 1 month after.RESULTS:There were 46 men and 18 women included in the study. Mean age was 58.3 years old, and nearly half of them (46.9%) were between 50-59 years old. More than half (58.7%) presented with moderate to a severe stroke and mean GFAP serum level was 0.113 ± 0.029 ng/mL. GFAP serum levels had a significant correlation with NIHSS after 1 month (p = 0.04, r = 0.259).CONCLUSION:There is a significant correlation between GFAP serum levels with stroke severity scale after 1 month of stroke onset.

Diagnostic value of serum glial fibrillary acidic protein and S100B serum levels in emergency medicine patients with traumatic versus nontraumatic intracerebral hemorrhage.

Glial fibrillary acidic protein (GFAP) is a brain-specific astroglial protein that is released into the blood soon after traumatic brain injury by mature astrocytes. S100B is rapidly released into the cerebrospinal fluid and bloodstream after brain damage. We compared the serum concentrations of these proteins in patients with severe head trauma (bleeding and/or fracture) or nontraumatic intracerebral hemorrhage and healthy individuals. The study included 63 patients (33 males and 30 females) with traumatic cerebral hemorrhage and/or cranial bone fractures or nontraumatic cerebral hemorrhage and 30 healthy control subjects. The reasons for attending the emergency department were as follows: fall from a height (n = 32), traffic accident (n = 18), nontraumatic intracerebral hemorrhage (n = 6), animal kick to the head (n = 4), and blow to the head (n = 3). Of the 63 patients included in the study, 33 (52.4%) were male and 30 (47.6%) were female. Of the 30 healthy controls, 12 (40%) were male and 18 (60%) were female. The average age of the patients was 27 years (range, 1 month to 86 years) and the average age of the control group was 21 years (range, 18-30 years). The mean serum GFAP concentrations were 86.37 ng/mL in the patients and 38.07 ng/mL in the controls (P < 0.05). The mean serum S100B concentrations were 428.37 pg/mL in the patients and 103.44 pg/mL in the controls (P < 0.05). Eight (12.7%) patients died in the hospital; of those, the mean GCS score was 4.6, and the mean GFAP and S100B levels were 127.8 ng/mL and 860.6 pg/mL, respectively. The GFAP and S100B concentrations were significantly higher in patients with traumatic or nontraumatic brain injury than in healthy individuals, indicating that serum levels of these biomarkers may provide an alternative to computed tomography for the diagnosis of brain injury.

Levels and Age Dependency of Neurofilament Light and Glial Fibrillary Acidic Protein in Healthy Individuals and Their Relation to the Brain Parenchymal Fraction.

BackgroundNeurofilament light (NFL) and Glial Fibrillary Acidic Protein (GFAP) are integral parts of the axonal and astrocytal cytoskeletons respectively and are released into the cerebrospinal fluid (CSF) in cases of cellular damage. In order to interpret the levels of these biomarkers in disease states, knowledge on normal levels in the healthy is required. Another biomarker for neurodegeneration is brain atrophy, commonly measured as brain parenchymal fraction (BPF) using magnetic resonance imaging (MRI). Potential correlations between levels of NFL, GFAP and BPF in healthy individuals have not been investigated.ObjectivesTo present levels of NFL and GFAP in healthy individuals stratified for age, and investigate the correlation between them as well as their correlation with BPF.MethodsThe CSF was analysed in 53 healthy volunteers aged 21 to 70 (1 sample missing for GFAP analysis) and 48 of the volunteers underwent determination of BPF using MRI.ResultsMean (±SD) NFL was 355 ng/L (±214), mean GFAP was 421 ng/L (±129) and mean BPF was 0.867 (±0.035). All three biomarkers correlated with age. NFL also correlated with both GFAP and BPF. When controlled for age, only the correlation between NFL and GFAP retained statistical significance.ConclusionsThis study presents data on age-stratified levels of NFL and GFAP in the CSF of healthy individuals. There is a correlation between levels of NFL and GFAP and both increase with age. A correlation between NFL and BPF was also found, but did not retain statistical significance if controlled for age.

Longitudinal changes in the DTI measures, anti-GFAP expression and levels of serum inflammatory cytokines following mild traumatic brain injury

The majority of human mild traumatic brain injuries (mTBI; 70%) lack radiological evidence of injury, yet may present long term cognitive, and behavioral dysfunctions. With the hypothesis of evident damaged neural tissue and immunological consequences during acute phase of mTBI, we used closed skull weight-drop TBI model to address human mTBI condition. Serum cytokines (TNF-α, IL-10) and glial fibrillary acidic protein (GFAP) expression were examined at day 0 (control, pre-injury), 4h, day 1, day 3 and day 5 post injury (PI). Diffusion tensor imaging (DTI) was performed at similar timepoints to identify neuroinflammation translation into imaging abnormalities and monitor injury progression. DTI indices including mean diffusivity (MD), radial diffusivity (RD), fractional anisotropy and axial diffusivity values were quantified from cortex (CTX), hippocampus and corpus callosum regions. One way ANOVA showed significant increase in TNF-α at 4h and IL-10 at day 1 PI as compared to control. GFAP+ cells were significantly increased at day 3 and day 5 as compared to control in CTX. Repeated measures ANOVA revealed significant decreases in MD, RD values in CTX at day 3 and day 5 as compared to day 0. A significant, inverse correlation was observed between cortical MD (r=−0.74, p=0.01), AD (r=−0.60, p=0.03) and RD (r=−0.72, p=0.01) values with mean GFAP+ cells in the cortical region. These findings suggest that mTBI leads to elevated cytokine expression and subsequent hypertrophy of astrocytic processes. The increased numbers of reactive glial cells contribute diffusion restrictions in the CNS leading to reduced MD and RD values. These findings are in line with the deficits and pathologies associated with clinical mTBI, and support the use of mTBI model to address pathology and therapeutic options.

Non-neurological surgery and cerebrospinal fluid biomarkers for neuronal and astroglial integrity

Non-neurological surgery has both acute and long-term effects on the brain. Markers for Alzheimer pathology may be used to study surgically induced neurological changes relevant for postoperative confusion, asthenia or cognitive decline. Inflammatory biomarkers, total tau (T-tau) and phosphorylated tau (P-tau) were recently shown to increase progressively in the cerebrospinal fluid (CSF) during surgery for nasal CSF leak, suggesting a neuroinflammatory response with signs of neuronal damage. We used a study group of 35 patients, undergoing knee arthroplasty with a spinal blockade and propofol sedation, to replicate this finding. Five CSF biomarkers were analyzed before, 3h after and on the morning after the interventions: T-tau and P-tau for cortical axonal integrity and tangle pathology, respectively, the 42 amino acids form of amyloid β (Aβ42) for plaque formation, neurofilament light (NFL) for the integrity of large-caliber myelinated axons and glial fibrillary acidic protein (GFAp) for astroglial cell integrity. CSF T-tau concentrations increased significantly during and after surgery (p=0.028) and were significantly correlated with the administered doses of bupivacaine. P-tau, Aβ42 and NFL remained unchanged, while the mean GFAp concentration increased with a large standard deviation. CSF T-tau and P-tau correlated significantly with the CSF/serum albumin ratios as an indicator of blood-brain barrier permeability. Findings from earlier studies showing a significant increase in biomarkers for Alzheimer's pathology during surgery were partly replicated, as neurochemical signs of impaired cortical axonal integrity during non-neurological surgery were detected. Bupivacaine may be involved in these reactions.

“Super p53” Mice Display Retinal Astroglial Changes

Tumour-suppressor genes, such as the p53 gene, produce proteins that inhibit cell division under adverse conditions, as in the case of DNA damage, radiation, hypoxia, or oxidative stress (OS). The p53 gene can arrest proliferation and trigger death by apoptosis subsequent to several factors. In astrocytes, p53 promotes cell-cycle arrest and is involved in oxidative stress-mediated astrocyte cell death. Increasingly, astrocytic p53 is proving fundamental in orchestrating neurodegenerative disease pathogenesis. In terms of ocular disease, p53 may play a role in hypoxia due to ischaemia and may be involved in the retinal response to oxidative stress (OS). We studied the influence of the p53 gene in the structural and quantitative characteristics of astrocytes in the retina. Adult mice of the C57BL/6 strain (12 months old) were distributed into two groups: 1) mice with two extra copies of p53 (“super p53”; n = 6) and 2) wild-type p53 age-matched control, as the control group (WT; n = 6). Retinas from each group were immunohistochemically processed to locate the glial fibrillary acidic protein (GFAP). GFAP+ astrocytes were manually counted and the mean area occupied for one astrocyte was quantified. Retinal-astrocyte distribution followed established patterns; however, morphological changes were seen through the retinas in relation to p53 availability. The mean GFAP+ area occupied by one astrocyte in “super p53” eyes was significantly higher (p<0.05; Student’s t-test) than in the WT. In addition, astroglial density was significantly higher in the “super p53” retinas than in the WT ones, both in the whole-retina (p<0,01 Student’s t-test) and in the intermediate and peripheral concentric areas of the retina (p<0.05 Student’s t-test). This fact might improve the resistance of the retinal cells against OS and its downstream signalling pathways.

Glial Fibrillary Acidic Protein is Highly Correlated With Brain Injury

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein found in the cytoskeleton of astroglia. Recent work has indicated that GFAP may serve as a serum marker of traumatic brain injury (TBI) that is released after central nervous system cell damage. Serum from 51 critically injured trauma patients was prospectively collected on admission and on hospital day 2. All patients underwent an admission head computed tomography (CT) scan as a part of their clinical evaluation. Patients with facial fractures in the absence of documented TBI and patients with spinal cord injury were excluded. Demographic and outcome data were collected prospectively. Serum GFAP was measured in duplicate using enzyme-linked immunosorbent assay techniques. Thirty-nine (76%) of the 51 patients had CT-documented TBI. The study cohort was 72.5% men with a mean age of 43 years and mean Injury Severity Score (ISS) of 30.2. There were no statistically significant demographic differences between the two groups. At admission day, the mean GFAP level in non-TBI patients was 0.07 pg/mL compared with 6.77 pg/mL in TBI patients (p = 0.002). On day 2 the mean GFAP level was 0.02 in non-TBI patients compared with 2.17 in TBI patients (p = 0.003). Using regression analysis to control for age, sex, and ISS, the Head Abbreviated Injury Scale was predictive of the level of GFAP on both days 1 and 2 (p values 0.006 and 0.026, respectively). Although GFAP levels were not predictive of increased hospital length of stay, intensive care unit length of stay, or ventilator days, high GFAP levels on hospital day 2 were predictive of mortality when controlling for age, sex, and ISS (odds ratio 1.45, p value 0.028). The area under the receiver operating characteristic curve for GFAP was 0.90 for day 1 and 0.88 for day 2. A GFAP cutoff point of 1 pg/mL yielded 100% specificity and 50% to 60% sensitivity for TBI. GFAP is a serum marker of TBI, and persistent elevation on day 2 is predictive of increased mortality. Excellent specificity for CT-documented brain injury was found using a cutoff point of 1 pg/mL.

Release of glial fibrillary acidic protein is related to the neurovascular status in acute ischemic stroke

This study aimed at an analysis of glial fibrillary acidic protein (GFAP) in acute ischemic stroke, its association with the neurovascular status and its potential value as monitoring parameter. In 53 consecutive patients, serial venous blood samples were taken on admission, 6, 12, 18, 24, 48, 72, 96, and 120 h after stroke onset. The neurovascular status was assessed by repetitive extracranial and transcranial duplex sonography. Neurologic deficits were quantified by the National Institutes of Health stroke scale, and functional outcome was assessed with the modified Rankin Scale. Mean GFAP values were elevated from admission on with highest levels 48 h after stroke onset. GFAP release was highly correlated with severity of neurologic deficits and infarct volume. In patients with persistent middle cerebral artery occlusion, GFAP increased significantly compared with patients with normal sonographic findings (P = 0.019) and recanalization after thrombolysis resulted in a significant reduced increase (P = 0.038). GFAP concentrations were associated with the functional outcome after 3 months. Release kinetics of GFAP are associated with patients clinical deficits and infarct volume, depend on the neurovascular status on admission and on early recanalization after thrombolysis, and may be used as an additional predictor of the early course and functional outcome.

Glial fibrillary acidic protein mRNA levels in the cingulate cortex of individuals with depression, bipolar disorder and schizophrenia

Recent studies have shown a decrease in glial number and glial fibrillary acidic protein (GFAP) levels in the frontal and cingulate cortices of individuals with mood disorders and schizophrenia. In an attempt to verify and expand these findings we examined GFAP messenger ribonucleic acid (mRNA) levels in postmortem sections of the anterior cingulate cortex (ACC) from the Stanley Neuropathology Consortium (SNC). The consortium consists of 15 cases in each of four groups (schizophrenia, bipolar disorder, non-psychotic depression and unaffected controls). By in situ hybridization, we found higher levels of GFAP mRNA in white matter and at the pial surface as compared with gray matter levels in all cases. In the white matter of ACC we detected a significant effect of diagnosis ( P<0.04) with GFAP mRNA levels decreased in individuals with schizophrenia and bipolar disorder as compared with normal controls. In the gray matter there was a significant effect of layer ( P<0.01) with the highest levels of GFAP mRNA in layer VI in all groups. As in the white matter, the mean GFAP mRNA levels were decreased in individuals with schizophrenia and bipolar disorder as compared with the unaffected controls, however the difference failed to reach statistical significance. Thus, astrocytes positive for GFAP may contribute to the decrease in glial density previously described in subjects with major mental illness, however the relative contribution of astrocytes may vary with diagnosis.

HLA-DR4 influences glial activity in Alzheimer's disease hippocampus.

The importance of inflammatory/immune mechanisms in Alzheimer's disease is supported by evidence that the human leukocyte antigen (HLA)-DR genotype influences risk of the disease, with a protective effect associated with the HLA-DR4 allele. We investigated the influence of the HLA-DR4 allele on glial activity, assessed by quantification of glial fibrillary acidic protein (GFAP), in hippocampal tissue from subjects with Alzheimer's disease. The mean GFAP level was significantly higher in Alzheimer's disease hippocampal specimens lacking the HLA-DR4 allele compared to specimens with similar neuropathological findings that were HLA-DR4 positive. Apolipoprotein E genotype had no influence on GFAP levels. These results indicate that HLA-DR4 may exert a protective influence on Alzheimer's disease via modulation of glial activity.

Molecular characterization of glioblastoma cell differentiation.

Induction of cellular differentiation continues to be an attractive therapeutic strategy for malignant glioma. The purpose of this study was to develop a convenient in vitro model system for glioblastoma differentiation and to then characterize it using conventional techniques and flow cytometry. A subline of U138 MG cells ("U138B") was treated with 0 to 4 mmol/L sodium butyrate (or serum deprivation) for up to 96 hours. Cells were initially studied for effects on proliferation, morphology, and glial fibrillary acidic protein (GFAP) staining. Northern blot and immunoblot analyses of c-myc expression were performed. Multiparameter flow cytometry was then used to analyze GFAP, c-myc protein, and total cellular protein fluorescence and to relate them to changes in cell cycle distribution. Butyrate treatment produced a dose-dependent inhibition of cellular proliferation and changes in morphology, GFAP staining, and c-myc expression consistent with a differentiation response. Detailed flow cytometric studies, including subpopulation analysis, showed that during 72 hours of treatment with 2 mmol/L butyrate, mean GFAP fluorescence increased to 420%, whereas c-myc protein decreased to 45 +/- 13% and total cellular protein increased to 181 +/- 17%. The effects of butyrate were distinct from those of serum deprivation and were not simply the result of cells shifting into Gzero/G1. The butyrate-induced responses of the U138B cell line provide a convenient model system for studying the molecular events accompanying the differentiation of glioblastoma cells. Multiparameter flow cytometry is a useful technique for characterizing such differentiation.

Increased cerebrospinal fluid levels of glial fibrillary acidic protein (GFAp) in Lyme neuroborreliosis.

Glial fibrillary acidic protein (GFAp), the main protein constituent of the intermediate filaments of astrocytes, was analysed in the cerebrospinal fluid (CSF) of 20 patients with Lyme neuroborreliosis as a marker of the astroglial reaction. The mean GFAp level before antibiotic treatment in the study group was significantly elevated (592 pg/ml +/- 596 [SD]) compared to that in 24 healthy controls (121 +/- 87 [SD]) (p < 0.01). The highest CSF-GFAp levels were seen in the patients with the most severe disease, but the levels were also increased in patients with peripheral paresis, such as facial palsy with no or only minor encephalitic symptoms. This implies that the infection was not limited to radix dorsalis or the meningeal tissues, but affected the central nervous system as well. Furthermore, the astroglial reaction seemed to occur early in Lyme neuroborreliosis since CSF-GFAp levels were elevated also in patients with recent (< 3 weeks) onset of disease. After antibiotic treatment, the GFAp levels decreased. It is suggested the CSF-GFAp concentrations might be useful for monitoring CNS involvement in Lyme neuroborreliosis.

Analysis of glial fibrillary acidic protein in the cerebrospinal fluid of children investigated for encephalopathy.

The clinical application of a newly developed highly sensitive ELISA method (20) to assay glial fibrillary acidic protein (GFAP) in the cerebrospinal fluid (CSF) was investigated in children and adolescents with neurological disorders. GFAP analysis was explored as a tool to differentiate disorders with ongoing astrocytosis. A consecutive series of 34 subjects, 17 boys and 17 girls, with nonprogressive and progressive neurological encephalopathies was compared to 10 healthy controls. The mean CSF GFAP concentration of the controls was 60.6 +/- 54 ng/l (SD). The group of 24 subjects (12 boys and 12 girls) with progressive neurologic disorders had higher mean CSF GFAP levels than the group of 10 subjects (5 boys and 5 girls) with non-progressive disorders, 222.6 +/- 186 and 127.5 +/- 86 ng/l, respectively. The progressive encephalopathies differed significantly from controls (p < 0.01) while the non-progressive did not. The mean GFAP concentration of the epilepsy cases (n = 18) and non-epilepsy cases (n = 16) was 212.9 +/- 196 and 174.0 +/- 132 ng/l, respectively. The epilepsy cases differed significantly from controls which could be explained by the dominance of progressive cases (15 out of 18).(ABSTRACT TRUNCATED AT 250 WORDS)