Dataset Information

Plasma Glial Fibrillary Acidic Protein Levels Differ Along the Spectra of Amyloid Burden and Clinical Disease Stage.

ABSTRACT:

Background

Measuring plasma glial fibrillary acidic protein (GFAP) alongside cortical amyloid-? (A?) may shed light on astrocytic changes in aging and Alzheimer's disease (AD).

Objective

To examine associations between plasma GFAP and cortical A? deposition in older adults across the typical aging-to-AD dementia spectrum.

Methods

We studied two independent samples from UCSF (Cohort 1, N?=?50; Cohort 2, N?=?37) covering the spectra of clinical severity (CDR Sum of Boxes; CDR-SB) and A?-PET burden. A?-PET was completed with either florbetapir or Pittsburgh Compound B and standardized uptake value ratios were converted to the Centiloid (CL) scale for analyses. All participants with CDR-SB?>?0 were A?-PET positive, while clinically normal participants (CDR-SB?=?0) were a mix of A?-PET positive and negative. Regression analyses evaluated main effect and interaction associations between plasma GFAP, A?-PET, and clinical severity.

Results

In both cohorts, plasma GFAP increased linearly with A?-PET CLs in clinically normal older adults. In Cohort 2, which included participants with more severe clinical dysfunction and A?-PET burden, the association between A? and GFAP became curvilinear (inverted U-shape; quadratic model R2 change?=?0.165, p?=?0.009), and A?-PET interacted with CDR-SB (R2 change?=?0.164, p?=?0.007): older adults with intermediate functional impairment (CDR-SB?=?0.5-4.0) showed a weak (negative) association between A?-PET CLs and plasma GFAP, while older adults with dementia (CDR-SB?>?4.0) showed a strong, negative association of higher A?-PET CLs with lower plasma GFAP.

Conclusion

The relationship between astrocytic integrity and cortical A? may be highly dynamic, with linear, positive associations early in disease that diverge in more severe disease stages.

SUBMITTER: Asken BM

PROVIDER: S-EPMC7727314 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Publications

Plasma Glial Fibrillary Acidic Protein Levels Differ Along the Spectra of Amyloid Burden and Clinical Disease Stage.

Asken Breton M BM Elahi Fanny M FM La Joie Renaud R Strom Amelia A Staffaroni Adam M AM Lindbergh Cutter A CA Apple Alexandra C AC You Michelle M Weiner-Light Sophia S Brathaban Nivetha N Fernandes Nicole N Karydas Anna A Wang Paul P Rojas Julio C JC Boxer Adam L AL Miller Bruce L BL Rabinovici Gil D GD Kramer Joel H JH Casaletto Kaitlin B KB

Journal of Alzheimer's disease : JAD 20200101 1

<h4>Background</h4>Measuring plasma glial fibrillary acidic protein (GFAP) alongside cortical amyloid-β (Aβ) may shed light on astrocytic changes in aging and Alzheimer's disease (AD).<h4>Objective</h4>To examine associations between plasma GFAP and cortical Aβ deposition in older adults across the typical aging-to-AD dementia spectrum.<h4>Methods</h4>We studied two independent samples from UCSF (Cohort 1, N = 50; Cohort 2, N = 37) covering the spectra of clinical severity (CDR Sum of Boxes; CDR ...[more]

PMID: 32986672

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Project description:Background Blood-based biomarkers for Alzheimer’s disease (AD) might facilitate identification of participants for clinical trials targeting amyloid beta (Abeta) accumulation, and aid in AD diagnostics. We examined the potential of plasma markers Abeta(1-42/1-40), glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) to identify cerebral amyloidosis and/or disease severity. Methods We included individuals with a positive (n?=?176: 63?±?7?years, 87 (49%) females) or negative (n?=?76: 61?±?9?years, 27 (36%) females) amyloid PET status, with syndrome diagnosis subjective cognitive decline (18 PET+, 25 PET?), mild cognitive impairment (26 PET+, 24 PET?), or AD-dementia (132 PET+). Plasma Abeta(1-42/1-40), GFAP, and NfL were measured by Simoa. We applied two-way ANOVA adjusted for age and sex to investigate the associations of the plasma markers with amyloid PET status and syndrome diagnosis; logistic regression analysis with Wald’s backward selection to identify an optimal panel that identifies amyloid PET positivity; age, sex, and education-adjusted linear regression analysis to investigate associations between the plasma markers and neuropsychological test performance; and Spearman’s correlation analysis to investigate associations between the plasma markers and medial temporal lobe atrophy (MTA). Results Abeta(1-42/1-40) and GFAP independently associated with amyloid PET status (p?=?0.009 and p?<?0.001 respectively), and GFAP and NfL independently associated with syndrome diagnosis (p?=?0.001 and p?=?0.048 respectively). The optimal panel identifying a positive amyloid status included Abeta(1-42/1-40) and GFAP, alongside age and APOE (AUC?=?88% (95% CI 83–93%), 82% sensitivity, 86% specificity), while excluding NfL and sex. GFAP and NfL robustly associated with cognitive performance on global cognition and all major cognitive domains (GFAP: range standardized ? (s?)?=???0.40 to ??0.26; NfL: range s??=???0.35 to ??0.18; all: p?<?0.002), whereas Abeta(1-42/1-40) associated with global cognition, memory, attention, and executive functioning (range s??=?0.22 – 0.11; all: p?<?0.05) but not language. GFAP and NfL showed moderate positive correlations with MTA (both: Spearman’s rho>?0.33, p?<?0.001). Abeta(1-42/1-40) showed a moderate negative correlation with MTA (Spearman’s rho?=???0.24, p?=?0.001). Discussion and conclusions Combination of plasma Abeta(1-42/1-40) and GFAP provides a valuable tool for the identification of amyloid PET status. Furthermore, plasma GFAP and NfL associate with various disease severity measures suggesting potential for disease monitoring.

Project description:ImportanceGlial fibrillary acidic protein (GFAP) is a marker of reactive astrogliosis that increases in the cerebrospinal fluid (CSF) and blood of individuals with Alzheimer disease (AD). However, it is not known whether there are differences in blood GFAP levels across the entire AD continuum and whether its performance is similar to that of CSF GFAP.ObjectiveTo evaluate plasma GFAP levels throughout the entire AD continuum, from preclinical AD to AD dementia, compared with CSF GFAP.Design, setting, and participantsThis observational, cross-sectional study collected data from July 29, 2014, to January 31, 2020, from 3 centers. The Translational Biomarkers in Aging and Dementia (TRIAD) cohort (Montreal, Canada) included individuals in the entire AD continuum. Results were confirmed in the Alzheimer's and Families (ALFA+) study (Barcelona, Spain), which included individuals with preclinical AD, and the BioCogBank Paris Lariboisière cohort (Paris, France), which included individuals with symptomatic AD.Main outcomes and measuresPlasma and CSF GFAP levels measured with a Simoa assay were the main outcome. Other measurements included levels of CSF amyloid-β 42/40 (Aβ42/40), phosphorylated tau181 (p-tau181), neurofilament light (NfL), Chitinase-3-like protein 1 (YKL40), and soluble triggering receptor expressed on myeloid cells 2 (sTREM2) and levels of plasma p-tau181 and NfL. Results of amyloid positron emission tomography (PET) were available in TRIAD and ALFA+, and results of tau PET were available in TRIAD.ResultsA total of 300 TRIAD participants (177 women [59.0%]; mean [SD] age, 64.6 [17.6] years), 384 ALFA+ participants (234 women [60.9%]; mean [SD] age, 61.1 [4.7] years), and 187 BioCogBank Paris Lariboisière participants (116 women [62.0%]; mean [SD] age, 69.9 [9.2] years) were included. Plasma GFAP levels were significantly higher in individuals with preclinical AD in comparison with cognitively unimpaired (CU) Aβ-negative individuals (TRIAD: Aβ-negative mean [SD], 185.1 [93.5] pg/mL, Aβ-positive mean [SD], 285.0 [142.6] pg/mL; ALFA+: Aβ-negative mean [SD], 121.9 [42.4] pg/mL, Aβ-positive mean [SD], 169.9 [78.5] pg/mL). Plasma GFAP levels were also higher among individuals in symptomatic stages of the AD continuum (TRIAD: CU Aβ-positive mean [SD], 285.0 [142.6] pg/mL, mild cognitive impairment [MCI] Aβ-positive mean [SD], 332.5 [153.6] pg/mL; AD mean [SD], 388.1 [152.8] pg/mL vs CU Aβ-negative mean [SD], 185.1 [93.5] pg/mL; Paris: MCI Aβ-positive, mean [SD], 368.6 [158.5] pg/mL; AD dementia, mean [SD], 376.4 [179.6] pg/mL vs CU Aβ-negative mean [SD], 161.2 [67.1] pg/mL). Plasma GFAP magnitude changes were consistently higher than those of CSF GFAP. Plasma GFAP more accurately discriminated Aβ-positive from Aβ-negative individuals than CSF GFAP (area under the curve for plasma GFAP, 0.69-0.86; area under the curve for CSF GFAP, 0.59-0.76). Moreover, plasma GFAP levels were positively associated with tau pathology only among individuals with concomitant Aβ pathology.Conclusions and relevanceThis study suggests that plasma GFAP is a sensitive biomarker for detecting and tracking reactive astrogliosis and Aβ pathology even among individuals in the early stages of AD.

Project description:BackgroundAstrocytes play an essential role in neuroinflammation and are involved in the pathogenesis of neurodenegerative diseases. Studies of glial fibrillary acidic protein (GFAP), an astrocytic damage marker, may help advance our understanding of different neurodegenerative diseases. In this study, we investigated the diagnostic performance of plasma GFAP (pGFAP), plasma neurofilament light chain (pNfL) and their combination for frontotemporal dementia (FTD) and Alzheimer's disease (AD) and their clinical utility in predicting disease progression.MethodspGFAP and pNfL concentrations were measured in 72 FTD, 56 AD and 83 cognitively normal (CN) participants using the Single Molecule Array technology. Of the 211 participants, 199 underwent cerebrospinal (CSF) analysis and 122 had magnetic resonance imaging. We compared cross-sectional biomarker levels between groups, studied their diagnostic performance and assessed correlation between CSF biomarkers, cognitive performance and cortical thickness. The prognostic performance was investigated, analyzing cognitive decline through group comparisons by tertile.ResultsUnlike pNfL, which was increased similarly in both clinical groups, pGFAP was increased in FTD but lower than in AD (all P < 0.01). Combination of both plasma markers improved the diagnostic performance to discriminate FTD from AD (area under the curve [AUC]: combination 0.78; pGFAP 0.7; pNfL 0.61, all P < 0.05). In FTD, pGFAP correlated with cognition, CSF and plasma NfL, and cortical thickness (all P < 0.05). The higher tertile of pGFAP was associated with greater change in MMSE score and poor cognitive outcome during follow-up both in FTD (1.40 points annually, hazard ratio [HR] 3.82, P < 0.005) and in AD (1.20 points annually, HR 2.26, P < 0.005).ConclusionspGFAP and pNfL levels differ in FTD and AD, and their combination is useful for distinguishing between the two diseases. pGFAP could also be used to track disease severity and predict greater cognitive decline during follow-up in patients with FTD.

Project description:Background: Neurofilament light chain (NfL) and glial fibrilliary acidic protein (GFAP) have been suggested to be biomarkers of the pathophysiological process of neuromyelitis optica spectrum disorders (NMOSD), but the relationship between the plasma levels of these molecules with disease activity and treatment is incompletely understood. Objective: To investigate the treatment effects of disease-modifying drugs on plasma neurofilament light chain (pNfL) and plasma glial fibrillary acidic protein (pGFAP) and explore the predictive value of pNfL and pGFAP in the activity of NMOSD. Methods: pNfL and pGFAP levels were measured using single-molecule arrays in 72 patients with NMOSD and 38 healthy controls (HCs). Patients with NMOSD received tocilizumab (n = 29), rituximab (n = 23), oral prednisone (n = 16), and oral azathioprine or mycophenolate mofetil (n = 4). Results: NMOSD patients had significantly higher pNfL and pGFAP levels than HCs (pNfL, 18.3 (11.2–39.3) versus 11.5 (7.0–23.3) pg/mL; p = 0.001; pGFAP, 149.7 (88.6–406.5) versus 68.7 (59.4–80.8) pg/mL; p < 0.001). Multivariable regression analyses indicated that baseline pNfL concentration was associated with age (p = 0.017), Expanded Disability Status Scale (EDSS) score (p = 0.002), and recent relapses (p < 0.001). Baseline pGFAP concentration was also associated with EDSS (p < 0.001) and recent relapses (p < 0.001). Compared with prednisone, tocilizumab and rituximab significantly reduced pNfL [tocilizumab, exp(β), 0.65; 95% confidence interval (CI), 0.56–0.75; p < 0.001; rituximab, exp(β), 0.79; 95% CI = 0.68–0.93; p = 0.005] and pGFAP levels [tocilizumab, exp(β), 0.64; 95% CI, 0.51–0.80; p < 0.001; rituximab, exp(β), 0.77; 95% CI, 0.61–0.98; p = 0.041] at the end of the study. The pNfL levels in the tocilizumab and rituximab groups were reduced to those of HCs [tocilizumab, 8.5 (7.06–17.90) pg/mL; p = 0.426; rituximab, 14.0 (9.94–21.80) pg/mL; p = 0.216]. However, the pGFAP levels did not decrease to those of HCs in NMOSD patients at the end of study [tocilizumab, 88.9 (63.4–131.8) pg/mL; p = 0.012; rituximab, 141.7 (90.8–192.7) pg/mL; p < 0.001]. Conclusion: pNfL and pGFAP may serve as biomarkers for NMOSD disease activity and treatment effects.

Dataset Information

Plasma Glial Fibrillary Acidic Protein Levels Differ Along the Spectra of Amyloid Burden and Clinical Disease Stage.

Background

Objective

Methods

Results

Conclusion

Publications

Plasma Glial Fibrillary Acidic Protein Levels Differ Along the Spectra of Amyloid Burden and Clinical Disease Stage.

Similar Datasets

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