Association of Serum GFAP with Functional and Neurocognitive Outcome in Sporadic Small Vessel Disease

Characterization of Chitinase 3-like protein 1 spatiotemporal distribution in human post-traumatic brain contusions and other neuropathological scenarios

Chitinase 3-like protein 1 (CHI3L1) is emerging as a promising biomarker for assessing intracranial lesion burden and predicting prognosis in traumatic brain injury (TBI) patients. Following experimental TBI, Chi3l1 transcripts were detected in reactive astrocytes located within the pericontusional cortex. However, the cellular sources of CHI3L1 in response to hemorrhagic contusions in human brain remain unidentified. Hence, we examined a comprehensive collection of histologically defined acute and subacute human cerebral contusions with various surgical intervals using immunohistochemistry, validated through double immunofluorescence for markers such as GFAP, NeuN, MBP, and Iba-1, along with Fluoro-Jade C histofluorescence staining. CHI3L1 was found at meningeal interfaces, showing significant thickening of subpial glial plate. Paradoxically, CHI3L1-positive astrocytes were identified in neuroanatomical locations distant from hemorrhagic foci, where numerous eosinophilic ischemic neurons also exhibited CHI3L1 immunoreactivity. CHI3L1 immunostaining extended into white matter tracts and highlighted various phagocytic or activated microglia forms after delayed surgical decompressions. Given these findings, we advise against using CHI3L1 as a reactive astrogliosis marker due to its expression in multiple cell types, including astrocytes, neurons, oligodendrocytes, ependymocytes, leptomeningeal cells, microglia, and blood vessels. This non-selective response underscores the potential for CHI3L1 elevation patterns in biofluids to reflect the overall lesion burden extent.

Blood biomarkers for vascular cognitive impairment based on neuronal function: a systematic review and meta-analysis

Vascular cognitive impairment (VCI) is increasingly recognized as the second most prevalent cause of dementia, primarily attributed to vascular risk factors and cerebrovascular disease. Numerous studies suggest that blood biomarkers may play a crucial role in the detection and prognosis of VCI. This study conducted a meta-analysis to evaluate the potential of various blood biomarkers associated with neuronal function as indicators of VCI. We searched four major databases-PubMed, Embase, Web of Science, and the Cochrane Library-up to December 31, 2023, for research on blood biomarkers for VCI. Of the 4,043 studies identified, 30 met the inclusion criteria for this review. The nine peripheral biomarkers analyzed for their association with neuronal function include amyloid beta 42 (Aβ42), amyloid beta 40 (Aβ40), Aβ42/Aβ40 ratio, total Tau (t-Tau), phosphorylated tau 181 (p-tau 181), neurofilament light (NfL), brain-derived neurotrophic factor (BDNF), S100B, and soluble receptor for advanced glycation end products (sRAGE). Our findings reveal that peripheral Aβ42, Aβ42/Aβ40 ratio, NfL, and S100B significantly differ between VCI and non-VCI groups, indicating their potential as blood biomarkers for VCI.

Quantitative assessments of white matter hyperintensities and plasma biomarkers can predict cognitive impairment and cerebral microbleeds in cerebral small vessel disease patients

The objective of this study is to examine the efficacy of magnetic resonance imaging (MRI) features and peripheral blood biomarkers in assessing cognitive function in patients with cerebral small vessel disease (CSVD). A total of 58 CSVD patients were recruited. Six features of white matter hyperintensities (WMHs) were derived from MRI scans. Additionally, five neurodegenerative biomarkers (Aβ40, Aβ42, t-tau, p-tau181, NfL) and 13 serum inflammatory cytokines (VILIP-1, CCL2, IL-6, IL-18, TNF-α, CX3CL, sTREM-1/2, VEGF, s-RAGE, BNDF, TGF-β1, β-NGF) were quantified. Cognitive assessments were conducted using standardized neuropsychological scales. Spearman analysis revealed that the volumetric characteristics (absolute area, upper area, bottom area, absolute area percentage, upper percentage, and bottom percentage) of WMHs were negatively correlated with performance on all cognitive scale measures except the verbal fluency test (VFT) (r < -0.3, p > 0.05), while they were positively correlated with plasma neurofilament light (NFL) levels (r > 0.4, p < 0.05). Additionally, serum tumor necrosis factor-α (TNF-α) and soluble receptor for advanced glycation end-products (s-RAGE) showed significant correlations with scales of speech function. An integrated model incorporating WMHs features, neurodegenerative biomarkers, and neuroinflammatory markers was developed, demonstrating high predictive accuracy for cognitive impairment with an area under the curve (AUC) of 0.95 (accuracy 0.88, sensitivity 0.87, specificity 0.89). Another integrated model that includes features of WMHs and inflammatory cytokines for predicting cerebral microbleeds (CMBs) achieved an AUC of 0.95 (accuracy 0.88, sensitivity 0.82, specificity 0.92). Our findings suggest that these markers have the potential to be used for the early detection of cognitive decline and CMBs in patients with CSVD.

Interaction Between DHCR24 and hsa_circ_0015335 Facilitates Cognitive Impairment in Cerebral Small Vessel Disease Patients

AIMS

The study attempted to determine the underlying role and regulation mechanism of 3β-hydroxysterol-Δ24 reductase (DHCR24) in the pathophysiology of cerebral small vessel disease-associated cognitive impairment (CSVD-CI). An RNA high-throughput sequencing and independent verification were conducted to identify potential circRNAs becoming the upstream regulator.

METHODS

RNA sequencing was performed in whole-blood samples in cohort 1 (10 CSVD-CI and 8 CSVD with cognitively normal [CSVD-CN] patients). The DHCR24 and candidate circRNAs were verified in an independent cohort 2 (45 CSVD-CI participants and 37 CSVD-CN ones). The study also analyzed comprehensive cognitive assessments, plasma molecular index, and brain structure imaging.

RESULTS

The expression of DHCR24 and has_circ_0015335 in whole-blood samples of CSVD-CI patients was significantly reduced compared to CSVD-CN patients in RNA sequencing and independent verification. Furthermore, the levels of DHCR24 and has_circ_0015335 were significantly related to global cognitive impairment in CSVD-CI patients. Meanwhile, DHCR24 could regulate the correlation between has_circ_0015335 expression and alterations in brain cortex in surface area, thickness, and volume in CSVD-CI patients. Additionally, hsa_circ_0015335 interacted with DHCR24 for plasma 24(S)-hydroxycholesterol levels among CSVD-CI patients.

CONCLUSION

Interaction between DHCR24 and hsa_circ_0015335 cognitively impaired CSVD by affecting brain cholesterol metabolism and brain structural changes.

Perivascular spaces, plasma GFAP, and speeded executive function in neurodegenerative diseases

INTRODUCTION

We investigated the effect of perivascular spaces (PVS) volume on speeded executive function (sEF), as mediated by white matter hyperintensities (WMH) volume and plasma glial fibrillary acidic protein (GFAP) in neurodegenerative diseases.

METHODS

A mediation analysis was performed to assess the relationship between neuroimaging markers and plasma biomarkers on sEF in 333 participants clinically diagnosed with Alzheimer's disease/mild cognitive impairment, frontotemporal dementia, or cerebrovascular disease from the Ontario Neurodegenerative Disease Research Initiative.

RESULTS

PVS was significantly associated with sEF (c = -0.125 ± 0.054, 95% bootstrap confidence interval [CI] [-0.2309, -0.0189], p = 0.021). This effect was mediated by both GFAP and WMH.

DISCUSSION

In this unique clinical cohort of neurodegenerative diseases, we demonstrated that the effect of PVS on sEF was mediated by the presence of elevated plasma GFAP and white matter disease. These findings highlight the potential utility of imaging and plasma biomarkers in the current landscape of therapeutics targeting dementia.

HIGHLIGHTS

Perivascular spaces (PVS) and white matter hyperintensities (WMH) are imaging markers of small vessel disease. Plasma glial fibrillary protein acidic protein (GFAP) is a biomarker of astroglial injury. PVS, WMH, and GFAP are relevant in executive dysfunction from neurodegeneration. PVS's effect on executive function was mediated by GFAP and white matter disease.

NFL and GFAP in (pre)symptomatic RVCL-S carriers: a monogenic cerebral small vessel disease

BACKGROUND

Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) have emerged as biomarkers for cerebral small vessel disease (SVD). We investigated their role in a hereditary SVD model, retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S).

METHODS

NfL and GFAP levels of 17 pre-symptomatic, 22 symptomatic RVCL-S mutation carriers and 69 controls were measured using a Simoa assay. We assessed the association of serum and cerebrospinal fluid (CSF) levels of NfL and GFAP with RVCL-S symptomatology and neuropsychological functioning.

RESULTS

Serum and CSF NfL levels were higher in symptomatic RVCL-S compared to controls ≥ 45 years (33.5 pg/mL vs. 9.2 pg/mL, p < 0.01; 8.5*102 pg/mL vs. 3.9*102 pg/mL, p < 0.01, respectively). Serum NfL levels were higher in symptomatic RVCL-S than pre-symptomatic carriers (33.5 pg/mL vs. 5.9 pg/mL, p = 0.02). Pre-symptomatic RVCL-S carriers had increased CSF NfL levels compared to controls < 45 years (5.2*102 pg/mL vs. 1.9*102 pg/mL, p < 0.01). No differences were found in GFAP levels across groups, but in RVCL-S carriers higher serum levels of both NfL and GFAP were linked to poorer global cognitive functioning (β[95%CI] = - 2.86 [- 5.58 to - 0.13], p = 0.04 and β[95%CI] =  - 6.85 [- 11.54 to - 2.15], p = 0.01, respectively) and prolonged psychomotor test times (β[95%CI] = 6.71 [0.78-12.65], p = 0.03 and β[95%CI] = 13.84 [3.09-24.60], p = 0.01).

DISCUSSION

Higher levels of serum NfL and GFAP are associated with worse cognitive functioning in RVCL-S carriers and may serve as marker for disease progression. CSF NfL levels may serve as early marker as pre-symptomatic RVCL-S patients already show differences compared to young controls.

Inferior Frontal Sulcal Hyperintensity on Fluid-Attenuated Inversion Recovery Is Related to Cerebrospinal Fluid Clearance via Putative Meningeal Lymphatics

Inferior frontal sulcal hyperintensity (IFSH) on FLAIR sequence may indicate elevated cerebrospinal fluid (CSF) wastes. The objective of this study was to investigate its association with the clearance function of putative meningeal lymphatic vessels (mLVs). We included patients who underwent FLAIR sequence and dynamic contrast MRI with intrathecal administration of contrast agent. The visibility of IFSH was quantitatively assessed by measuring the mean signal intensity of inferior frontal sulci on 2D FLAIR. The clearance function of putative mLVs was defined as the percentage change of signal unite ratio in the parasagittal dura from baseline to 4.5, 15 and 39 hours after intrathecal injection on dynamic contrast MRI. Additionally, imaging markers of cerebral small vessel disease, including white matter hyperintensities and enlarged perivascular spaces, were measured. Correlation analysis and linear regression were employed to verify the association of IFSH with the clearance function of mLVs. A total of 76 patients were included in the study. The visibility of IFSH was found to be associated with the percentage change of signal unite ratio in parasagittal dura from baseline to 15 and 39 hours in adjusted analyses. Furthermore, the visibility of IFSH was positively related to the age, scores of both periventricular and deep white matter hyperintensities, and the grade of enlarged perivascular spaces in centrum semiovale. These findings suggest that the visibility of IFSH on 2D FLAIR may serve as an indicator of clearance dysfunction of mLVs and may be implicated in the development of cerebral small vessel disease.

Blood-based biomarkers of cerebral small vessel disease

Age-associated cerebral small vessel disease (CSVD) represents a clinically heterogenous condition, arising from diverse microvascular mechanisms. These lead to chronic cerebrovascular dysfunction and carry a substantial risk of subsequent stroke and vascular cognitive impairment in aging populations. Owing to advances in neuroimaging, in vivo visualization of cerebral vasculature abnormities and detection of CSVD, including lacunes, microinfarcts, microbleeds and white matter lesions, is now possible, but remains a resource-, skills- and time-intensive approach. As a result, there has been a recent proliferation of blood-based biomarker studies for CSVD aimed at developing accessible screening tools for early detection and risk stratification. However, a good understanding of the pathophysiological processes underpinning CSVD is needed to identify and assess clinically useful biomarkers. Here, we provide an overview of processes associated with CSVD pathogenesis, including endothelial injury and dysfunction, neuroinflammation, oxidative stress, perivascular neuronal damage as well as cardiovascular dysfunction. Then, we review clinical studies of the key biomolecules involved in the aforementioned processes. Lastly, we outline future trends and directions for CSVD biomarker discovery and clinical validation.

Fluid biomarkers of the neurovascular unit in cerebrovascular disease and vascular cognitive disorders: A systematic review and meta-analysis

Background

The disruption of the neurovascular unit (NVU), which maintains the integrity of the blood brain barrier (BBB), has been identified as a critical mechanism in the development of cerebrovascular and neurodegenerative disorders. However, the understanding of the pathophysiological mechanisms linking NVU dysfunction to the disorders is incomplete, and reliable blood biomarkers to measure NVU dysfunction are yet to be established. This systematic review and meta-analysis aimed to identify biomarkers associated with BBB dysfunction in large vessel disease, small vessel disease (SVD) and vascular cognitive disorders (VCD).

Methods

A literature search was conducted in PubMed, EMBASE, Scopus and PsychINFO to identify blood biomarkers related to dysfunction of the NVU in disorders with vascular pathologies published until 20 November 2023. Studies that assayed one or more specific markers in human serum or plasma were included. Quality of studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. Effects were pooled and methodological heterogeneity examined using the random effects model.

Results

A total of 112 studies were included in this review. Where study numbers allowed, biomarkers were analysed using random effect meta-analysis for VCD (1 biomarker; 5 studies) and cerebrovascular disorders, including stroke and SVD (9 biomarkers; 29 studies) while all remaining biomarkers (n = 17 biomarkers; 78 studies) were examined through qualitative analysis. Results of the meta-analysis revealed that cerebrospinal fluid/serum albumin quotient (Q-Alb) reliably differentiates VCD patients from healthy controls (MD = 2.77; 95 % CI = 1.97-3.57; p < 0.0001) while commonly measured biomarkers of endothelial dysfunction (VEGF, VCAM-1, ICAM-1, vWF and E-selectin) and neuronal injury (NfL) were significantly elevated in vascular pathologies. A qualitative assessment of non-meta-analysed biomarkers revealed NSE, NfL, vWF, ICAM-1, VCAM-1, lipocalin-2, MMP-2 and MMP-9 levels to be upregulated in VCD, although these findings were not consistently replicated.

Conclusions

This review identifies several promising biomarkers of NVU dysfunction which require further validation. A panel of biomarkers representing multiple pathophysiological pathways may offer greater discriminative power in distinguishing possible disease mechanisms of VCD.

Vascular risk, gait, behavioral, and plasma indicators of VCID

INTRODUCTION

Cost-effective screening tools for vascular contributions to cognitive impairment and dementia (VCID) has significant implications. We evaluated non-imaging indicators of VCID using magnetic resonance imaging (MRI)-measured white matter (WM) damage and hypothesized that these indicators differ based on age.

METHODS

In 745 participants from the Mayo Clinic Study of Aging (≥50 years of age) with serial WM assessments from diffusion MRI and fluid-attenuated inversion recovery (FLAIR)-MRI, we examined associations between baseline non-imaging indicators (demographics, vascular risk factors [VRFs], gait, behavioral, plasma glial fibrillary acidic protein [GFAP], and plasma neurofilament light chain [NfL]) and WM damage across three age tertiles.

RESULTS

VRFs and gait were associated with diffusion changes even in low age strata. All measures (VRFs, gait, behavioral, plasma GFAP, plasma NfL) were associated with white matter hyperintensities (WMHs) but mainly in intermediate and high age strata.

DISCUSSION

Non-imaging indicators of VCID were related to WM damage and may aid in screening participants and assessing outcomes for VCID.

HIGHLIGHTS

Non-imaging indicators of VCID can aid in prediction of MRI-measured WM damage but their importance differed by age. Vascular risk and gait measures were associated with early VCID changes measured using diffusion MRI. Plasma markers explained variability in WMH across age strata. Most non-imaging measures explained variability in WMH and vascular WM scores in intermediate and older age groups. The framework developed here can be used to evaluate new non-imaging VCID indicators proposed in the future.

Efficacy of enhanced extracorporeal counterpulsation combined with atorvastatin in the treatment of cognitive impairment after stroke

BACKGROUND

Cerebral apoplexy patients are prone to cognitive impairment, and it is very important to choose appropriate treatment methods to improve their cognitive impairment after stroke.

AIM

To evaluate the effects of enhanced external counterpulsation (EECP) in conjunction with atorvastatin on cognitive function, neurotransmitter levels, and the repair of brain tissue damage in patients with cognitive impairment due to stroke.

METHODS

In this retrospective study, data from 60 patients with poststroke cognitive impairment due to stroke who were treated in our hospital from February 2021 to July 2022 were analyzed and divided into a treatment group (n = 30) and a control group (n = 30) according to the different nursing methods applied. Patients in the treatment group received EECP in addition to atorvastatin, while those in the control group received atorvastatin alone. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and activities of daily living (ADL) scale scores were compared between the two groups. Additionally, the two groups were compared in terms of serum acetylcholine (ACh), acetylcholinesterase (AChE), nitric oxide (NO), endothelin-1 (ET-1), β2-microglobulin (β2-MG), glial fibrillary acidic protein (GFAP), and visinin-like protein 1 (VILIP-1) in the serum. Blood flow measurements from the anterior cerebral artery (ACA), middle cerebral artery (MCA) and posterior cerebral artery (PCA) were compared between the two groups before and after treatment, and the pulsatility index (PI) and resistance index (RI) of each artery were determined.

RESULTS

MMSE, MoCA, and ADL scores all improved in both groups following treatment, with the study group showing more improvement than the control group (P < 0.05). After treatment, there were statistically significant increases in both ACh and NO levels, whereas decreases occurred in AChE, ET-1, β2-MG, VILIP-1, and GFAP, levels and the PI and RI of the left-ACA, right-ACA, left-MCA, right-MCA, left-PCA, and right-PCA. The study group showed greater gains in all metrics than the control group (P < 0.05).

CONCLUSION

EECP combined with atorvastatin is effective in the treatment of cognitive impairment after stroke and can effectively improve the cognitive function, neurotransmitter levels, and brain tissue damage status of patients.

Molecular biomarkers for vascular cognitive impairment and dementia

As disease-specific interventions for dementia are being developed, the ability to identify the underlying pathology and dementia subtypes is increasingly important. Vascular cognitive impairment and dementia (VCID) is the second most common cause of dementia after Alzheimer disease, but progress in identifying molecular biomarkers for accurate diagnosis of VCID has been relatively limited. In this Review, we examine the roles of large and small vessel disease in VCID, considering the underlying pathophysiological processes that lead to vascular brain injury, including atherosclerosis, arteriolosclerosis, ischaemic injury, haemorrhage, hypoperfusion, endothelial dysfunction, blood-brain barrier breakdown, inflammation, oxidative stress, hypoxia, and neuronal and glial degeneration. We consider the key molecules in these processes, including proteins and peptides, metabolites, lipids and circulating RNA, and consider their potential as molecular biomarkers alone and in combination. We also discuss the challenges in translating the promise of these biomarkers into clinical application.

Magnetic resonance imaging of white matter in Alzheimer's disease: a global bibliometric analysis from 1990 to 2022

Background

Alzheimer's disease (AD) is a common, progressive, irreversible, and fatal neurodegenerative disorder with rapidly increasing worldwide incidence. Although much research on magnetic resonance imaging (MRI) of the white matter (WM) in AD has been published, no bibliometric analysis study has investigated this issue. Thus, this study aimed to provide an overview of the current status, hotspots, and trends in MRI of WM in AD.

Methods

We searched for records related to MRI studies of WM in AD from 1990 to 2022 in the Web of Science Core Collection (WOSCC) database. CiteSpace (version 5.1.R8) and VOSviewer (version 1.6.19) software were used for bibliometric analyses.

Results

A total of 2,199 articles were obtained from this study. From 1990 to 2022, the number of published articles showed exponential growth of y = 4.1374e^0.1294x, with an average of 17.9 articles per year. The top country and institutions were the United States and the University of California Davis, accounting for 44.52 and 5.32% of the total studies, respectively. The most productive journal was Neurology, and the most co-cited journal was Lancet Neurology. Decarli C was the most productive author. The current research frontier trend focuses on the association between small vessel disease and AD, the clinical application and exploration of diffusion MRI, and related markers.

Conclusion

This study provides an in-depth overview of publications on MRI of WM in AD, identifying the current research status, hotspots, and frontier trends in the field.

Serum YKL-40 Levels and White Matter Hyperintensities in Patients with Acute Ischemic Stroke

Background

White matter hyperintensity (WMH) is associated with risk of acute ischemic stroke (AIS) and poor outcomes after AIS. The purpose of this prospective study was to evaluate the association between serum YKL-40 levels and WMH burden in patients with AIS.

Methods

From February 2020 to March 2021, a total of 672 consecutive AIS patients with magnetic resonance imaging data were prospectively recruited form two centers. Serum YKL-40 levels were quantified using enzyme-linked immunosorbent assay. The burden of WMH was semiquantitatively measured by the Fazekas visual grading scale. According to severity of overall WMH, patients were dichotomized into none-mild WMH group (Fazekas score 0-2) or moderate-severe WMH group (Fazekas score 3-6). Besides, based on severity of periventricular WMH (PV-WMH) and deep WMH (D-WMH), patients were categorized as none-mild (Fazekas score 0-1) or moderate-severe (Fazekas score 2-3).

Results

Among the 672 patients, 335 (49.9%) participants were identified with moderate-severe overall WMH, 326 (48.5%) with moderate-severe PV-WMH and 262 (39.0%) with moderate-severe D-WMH. Compared with the first quartile of serum YKL-40, the adjusted odds ratio (OR) of the fourth quartile for moderate-severe PV-WMH was 2.473 (95% confidence interval [CI] 1.316-4.646; P=0.005). No significant association was observed between YKL-40 and overall WMH (OR 0.762; 95% CI 0.434-1.336; P=0.343) or D-WMH (OR 0.695; 95% CI 0.413-1.171; P=0.172).

Conclusion

Our results suggested that higher YKL-40 levels appeared to be associated with PV-WMH, but not with overall WMH or D-WMH in patients with AIS.