Association study of serum soluble TREM2 with vascular dementia in Chinese Han population

The pivotal role of microglia in injury and the prognosis of subarachnoid hemorrhage

Subarachnoid hemorrhage leads to a series of pathological changes, including vascular spasm, cellular apoptosis, blood-brain barrier damage, cerebral edema, and white matter injury. Microglia, which are the key immune cells in the central nervous system, maintain homeostasis in the neural environment, support neurons, mediate apoptosis, participate in immune regulation, and have neuroprotective effects. Increasing evidence has shown that microglia play a pivotal role in the pathogenesis of subarachnoid hemorrhage and affect the process of injury and the prognosis of subarachnoid hemorrhage. Moreover, microglia play certain neuroprotective roles in the recovery phase of subarachnoid hemorrhage. Several approaches aimed at modulating microglia function are believed to attenuate subarachnoid hemorrhage injury. This provides new targets and ideas for the treatment of subarachnoid hemorrhage. However, an in-depth and comprehensive summary of the role of microglia after subarachnoid hemorrhage is still lacking. This review describes the activation of microglia after subarachnoid hemorrhage and their roles in the pathological processes of vasospasm, neuroinflammation, neuronal apoptosis, blood-brain barrier disruption, cerebral edema, and cerebral white matter lesions. It also discusses the neuroprotective roles of microglia during recovery from subarachnoid hemorrhage and therapeutic advances aimed at modulating microglial function after subarachnoid hemorrhage. Currently, microglia in subarachnoid hemorrhage are targeted with TLR inhibitors, nuclear factor-κB and STAT3 pathway inhibitors, glycine/tyrosine kinases, NLRP3 signaling pathway inhibitors, Gasdermin D inhibitors, vincristine receptor α receptor agonists, ferroptosis inhibitors, genetic modification techniques, stem cell therapies, and traditional Chinese medicine. However, most of these are still being evaluated at the laboratory stage. More clinical studies and data on subarachnoid hemorrhage are required to improve the treatment of subarachnoid hemorrhage.

Tracking neuroinflammatory biomarkers in Alzheimer's disease: a strategy for individualized therapeutic approaches?

BACKGROUND

Recent trials of anti-amyloid-β (Aβ) monoclonal antibodies, including lecanemab and donanemab, in early Alzheimer disease (AD) showed that these drugs have limited clinical benefits and their use comes with a significant risk of serious adverse events. Thus, it seems crucial to explore complementary therapeutic approaches. Genome-wide association studies identified robust associations between AD and several AD risk genes related to immune response, including but not restricted to CD33 and TREM2. Here, we critically reviewed the current knowledge on candidate neuroinflammatory biomarkers and their role in characterizing the pathophysiology of AD.

MAIN BODY

Neuroinflammation is recognized to be a crucial and contributing component of AD pathogenesis. The fact that neuroinflammation is most likely present from earliest pre-stages of AD and co-occurs with the deposition of Aβ reinforces the need to precisely define the sequence and nature of neuroinflammatory events. Numerous clinical trials involving anti-inflammatory drugs previously yielded unfavorable outcomes in early and mild-to-moderate AD. Although the reasons behind these failures remain unclear, these may include the time and the target selected for intervention. Indeed, in our review, we observed a stage-dependent neuroinflammatory process in the AD brain. While the initial activation of glial cells counteracts early brain Aβ deposition, the downregulation in the functional state of microglia occurs at more advanced disease stages. To address this issue, personalized neuroinflammatory modulation therapy is required. The emergence of reliable blood-based neuroinflammatory biomarkers, particularly glial fibrillary acidic protein, a marker of reactive astrocytes, may facilitate the classification of AD patients based on the ATI(N) biomarker framework. This expands upon the traditional classification of Aβ ("A"), tau ("T"), and neurodegeneration ("N"), by incorporating a novel inflammatory component ("I").

CONCLUSIONS

The present review outlines the current knowledge on potential neuroinflammatory biomarkers and, importantly, emphasizes the role of longitudinal analyses, which are needed to accurately monitor the dynamics of cerebral inflammation. Such a precise information on time and place will be required before anti-inflammatory therapeutic interventions can be considered for clinical evaluation. We propose that an effective anti-neuroinflammatory therapy should specifically target microglia and astrocytes, while considering the individual ATI(N) status of patients.

Neuropeptides as Potential Biomarkers in Vascular Dementia

Neuropeptides are endogenous active substances within the central and peripheral nervous systems that play important roles in a wide range of brain functions, including metabolism, food intake, social behavior, reproduction, learning, sleep, and wakefulness. This article reviews recent advances in the involvement of neuropeptides in vascular dementia. Neuropeptides are present in the brain as chemical signals and last for nearly 50 years. Peptide hormones are chemical signals of the endocrine system. Thus, neuropeptides are the most diverse class of signaling molecules in the brain, involving the genomes of many mammals, encoding neuropeptide precursors and many bioactive neuropeptides. Here the aim is to describe the recent advances in classical neuropeptides, as well as putative neuropeptides from other families, in the control of or as diagnostic tools for vascular dementia. Additionally, its molecular mechanisms are described to explore new avenues of treatment and early diagnosis, as there is increasing evidence that dysregulation of vascular processes is associated with different pathological conditions.

Serum proinsulin levels as peripheral blood biomarkers in patients with cognitive impairment

Insulin has long been associated with dementia. Insulin affecting the clearance of amyloid-β peptide and phosphorylation of tau in the CNS. Proinsulin is a precursor of insulin and its elevated serum levels are associated with peripheral insulin resistance that may reduce brain insulin levels. Our study aimed to assess differences in serum proinsulin levels between normal and cognitive impairment groups. Prospective recruitment of elderly participants was initiated from October 2019 to September 2023. Patients were divided into "cognitive impairment" and "normal cognition" group. All participants had blood drawn and serum proinsulin was measured at baseline and 12 months. Neurocognitive testing was performed every 6 months. A total of 121 participants were recruited. Seventy-seven were in the normal cognition group and 44 in the cognitive impairment group. The glycemic control and prevalence of diabetes type 2 was similar between groups. Baseline serum proinsulin levels were higher in the cognitively impaired group compared to the normal group at baseline (p = 0.019) and correlated with worse cognitive scores. We identified cognitive status, age, and BMI as potential factors associated with variations in baseline proinsulin levels. Given the complex interplay between insulin and dementia pathogenesis, serum biomarkers related to insulin metabolism may exhibit abnormalities in cognitive impaired patients. Here we present the proinsulin levels in individuals with normal cognitive function versus those with cognitive impairment and found a significant difference. This observation may help identifying non-diabetic patients suitable for treatment with novel AD drugs that related to insulin pathway.

1,25-Dihydroxy Vitamin D3 Facilitates the M2 Polarization and β-Amyloid Uptake by Human Microglia in a TREM2-Dependent Manner

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia as the primary clinical symptom. The production and accumulation of aggregated β-amyloid (Aβ) in patient brain tissues is one of the hallmarks of AD pathogenesis. Microglia, brain-resident macrophages, produce inflammatory cytokines in response to Aβ oligomers or fibrils exacerbating Aβ pathology in AD. HMO6 cells were treated with Aβ42 in the presence or absence of 1,25-dihydroxy vitamin D₃ (1,25(OH)₂D₃) to determine its potential immunomodulatory effects, and the expression of pro-/anti-inflammatory cytokines, M1/M2-associated markers, Toll-like receptors (TLRs), and triggering receptor expressed on myeloid cells 2 (TREM2) was examined. 1,25(OH)₂D₃ was found to suppress Aβ-induced expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), M1 markers (CD86 and iNOS), and TLR2/4, whilst increasing the expression of anti-inflammatory cytokines (IL-4, IL-10, and CCL17) and M2 markers (CD206 and Arg-1). Furthermore, 1,25(OH)₂D₃ promoted TREM2 expression and Aβ uptake by HMO6 cells, and the enhancement of Aβ uptake and M2 polarization was revealed to be TREM2-dependent. The findings of this study suggest that 1,25(OH)₂D₃ facilitates M2 polarization and Aβ uptake in a TREM2-dependent manner.

Higher serum β2-microglobulin is a predictive biomarker for cognitive impairment in spinal cord injury

Objective

Recent studies have suggested that high levels of β2-microglobulin are linked to cognitive deterioration; however, it is unclear how this connects to spinal cord injury (SCI). This study sought to determine whether there was any association between cognitive decline and serum β2-microglobulin levels in patients with SCI.

Methods

A total of 96 patients with SCI and 56 healthy volunteers were enrolled as study participants. At the time of enrollment, specific baseline data including age, gender, triglycerides (TG), low-density lipoprotein (LDL), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), smoking, and alcohol use were recorded. Each participant was assessed by a qualified physician using the Montreal cognitive assessment (MoCA) scale. Serum β2-microglobulin levels were measured using an enzyme-linked immunosorbent assay (ELISA) reagent for β2-microglobulin.

Results

A total of 152 participants were enrolled, with 56 in the control group and 96 in the SCI group. There were no significant baseline data differences between the two groups (p > 0.05). The control group had a MoCA score of 27.4 ± 1.1 and the SCI group had a score of 24.3 ± 1.5, with the difference being significant (p < 0.05). The serum ELISA results revealed that the levels of β2-microglobulin in the SCI group were considerably higher (p < 0.05) than those in the control group (2.08 ± 0.17 g/mL compared to 1.57 ± 0.11 g/mL). The serum β2-microglobulin level was used to categorize the patients with SCI into four groups. As serum β2-microglobulin levels increased, the MoCA score reduced (p < 0.05). After adjustment of baseline data, further regression analysis showed that serum β2-microglobulin level remained an independent risk factor for post-SCI cognitive impairment.

Conclusions

Patients with SCI had higher serum levels of β2-microglobulin, which may be a biomarker for cognitive decline following SCI.

Traditional Chinese medicine promotes the control and treatment of dementia

Dementia is a syndrome that impairs learning and memory. To date, there is no effective therapy for dementia. Current prescription drugs, such as cholinesterase inhibitors, fail to improve the condition of dementia and are often accompanied by severe adverse effects. In recent years, the number of studies into the use of traditional Chinese medicine (TCM) for dementia treatment has increased, revealing a formula that could significantly improve memory and cognitive dysfunctions in animal models. TCM showed fewer adverse effects, lower costs, and improved suitability for long-term use compared with currently prescribed drugs. Due to the complexity of ingredients and variations in bioactivity of herbal medicines, the multi-target nature of the traditional Chinese formula affected the outcome of dementia therapy. Innovations in TCM will create a platform for the development of new drugs for the prevention and treatment of dementia, further strengthening and enhancing the current influence of TCM.

The effects and potential of microglial polarization and crosstalk with other cells of the central nervous system in the treatment of Alzheimer's disease

Microglia are resident immune cells in the central nervous system. During the pathogenesis of Alzheimer's disease, stimulatory factors continuously act on the microglia causing abnormal activation and unbalanced phenotypic changes; these events have become a significant and promising area of research. In this review, we summarize the effects of microglial polarization and crosstalk with other cells in the central nervous system in the treatment of Alzheimer's disease. Our literature search found that phenotypic changes occur continuously in Alzheimer's disease and that microglia exhibit extensive crosstalk with astrocytes, oligodendrocytes, neurons, and penetrated peripheral innate immune cells via specific signaling pathways and cytokines. Collectively, unlike previous efforts to modulate microglial phenotypes at a single level, targeting the phenotypes of microglia and the crosstalk with other cells in the central nervous system may be more effective in reducing inflammation in the central nervous system in Alzheimer's disease. This would establish a theoretical basis for reducing neuronal death from central nervous system inflammation and provide an appropriate environment to promote neuronal regeneration in the treatment of Alzheimer's disease.

Blood-Based Biomarkers for Alzheimer's Disease Diagnosis and Progression: An Overview

Alzheimer's Disease (AD) is a progressive neurodegenerative disease characterized by amyloid-β (Aβ) plaque deposition and neurofibrillary tangle accumulation in the brain. Although several studies have been conducted to unravel the complex and interconnected pathophysiology of AD, clinical trial failure rates have been high, and no disease-modifying therapies are presently available. Fluid biomarker discovery for AD is a rapidly expanding field of research aimed at anticipating disease diagnosis and following disease progression over time. Currently, Aβ1-42, phosphorylated tau, and total tau levels in the cerebrospinal fluid are the best-studied fluid biomarkers for AD, but the need for novel, cheap, less-invasive, easily detectable, and more-accessible markers has recently led to the search for new blood-based molecules. However, despite considerable research activity, a comprehensive and up-to-date overview of the main blood-based biomarker candidates is still lacking. In this narrative review, we discuss the role of proteins, lipids, metabolites, oxidative-stress-related molecules, and cytokines as possible disease biomarkers. Furthermore, we highlight the potential of the emerging miRNAs and long non-coding RNAs (lncRNAs) as diagnostic tools, and we briefly present the role of vitamins and gut-microbiome-related molecules as novel candidates for AD detection and monitoring, thus offering new insights into the diagnosis and progression of this devastating disease.

Serum Irisin as a Potential Biomarker for Cognitive Decline in Vascular Dementia

Background: Irisin, a new exercise-related myokine, has been shown to be associated with a variety of diseases including serious neurological disorders. However, whether irisin is involved in the pathogenesis of vascular dementia (VD) has not yet been reported. Our aim is to determine the serum irisin level in patients with VD and investigate its relationship with cognitive function. Methods: The subjects of the study were VD patients and controls with normal cognitive function who were hospitalized in the Neck-Shoulder and Lumbocrural Pain Hospital of Shandong First Medical University from July 2018 to June 2020. Upon admission, a cognitive function assessment was performed. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of irisin in serum. Results: During the study period, 187 subjects (82 controls and 105 VD patients) were included in the analysis. The serum irisin level of VD patients was significantly lower than that of the control group (p < 0.001). Spearman analysis showed that irisin was positively correlated with HLD-C and MoCA, and negatively correlated with all clinical characteristics except for HCY. Logistic regression analysis showed that after adjusting for all clinical characteristics, the serum irisin of VD patients still had a significant correlation with MoCA (β = 0.304, p = 0.029). According to receiver operating characteristic (ROC) curve analysis, the diagnostic accuracy for serum irisin levels on VD was 76% with the sensitivity and 71% with specificity respectively. Conclusions: These data indicate that a decrease in serum irisin levels is a powerful biological marker for cognitive decline in patients with VD, even after adjustment for risk factors. Further multi-center studies need to confirm this connection, which may pave the way for new treatment options.

Decreased Serum NCAM Levels Associated with Cognitive Impairment in Vascular Dementia

Objective

Neural cell adhesion molecule (NCAM), a glycoprotein widely distributed in the brain, has recently been shown to regulate neuroplasticity. However, the role of NCAM in vascular dementia (VaD) is still unclear. The purpose of this study is to determine whether NCAM is involved in the course of VaD.

Methods

Continuous recruitment of VaD patients and control population to join this study. Doctors or nurses are responsible for collecting their clinical characteristics including age, gender, formal education, heart rate, supine systolic blood pressure, supine diastolic blood pressure, fasting glucose, high-density lipoprotein, and low-density lipoprotein. Each participant received the Montreal Cognitive Assessment (MoCA) scale after being enrolled in the group. At the same time, their peripheral blood was collected, and their serum NCAM levels were measured by enzyme-linked immunosorbent assay (ELISA).

Results

98 VaD patients and 83 age- and sex-matched controls were enrolled. There was no significant statistical difference between the VaD group and the control group in terms of the comparison of clinical characteristics (p > 0.05). The MoCA score of VaD patients was significantly lower than that of the controls (27.9 ± 1.4 vs. 23.0 ± 2.1 points, p < 0.001). In addition, the circulating NCAM level of VaD patients was also significantly lower than that of controls (21.7 ± 3.8 vs. 17.6 ± 4.2 ng/mL, p < 0.001). The circulating NCAM level of VaD patients was significantly positively correlated with MoCA score (r = 0.285, p = 0.026). After adjusting for clinical characteristics, circulating NCAM levels are still an independent pathogenic factor of VaD (regression coefficient = 0.223, p = 0.034).

Conclusions

VaD patients have low circulating NCAM levels, which can be used as a potential predictor of VaD.

Microglia Biomarkers in Alzheimer's Disease

Early detection and clinical diagnosis of Alzheimer's disease (AD) have become an extremely important link in the prevention and treatment of AD. Because of the occult onset, the diagnosis and treatment of AD based on clinical symptoms are increasingly challenged by current severe situations. Therefore, molecular diagnosis models based on early AD pathological markers have received more attention. Among the possible pathological mechanisms, microglia which are necessary for normal brain function are highly expected and have been continuously studied in various models. Several AD biomarkers already exist, but currently there is a paucity of specific and sensitive microglia biomarkers which can accurately measure preclinical AD. Bringing microglia biomarkers into the molecular diagnostic system which is based on fluid and neuroimaging will play an important role in future scientific research and clinical practice. Furthermore, developing novel, more specific, and sensitive microglia biomarkers will make it possible to pharmaceutically target chemical pathways that preserve beneficial microglial functions in response to AD pathology. This review discusses microglia biomarkers in the context of AD.

IL-33 as a Novel Serum Prognostic Marker of Intracerebral Hemorrhage

Objective

Interleukin 33 (IL-33) is a key cytokine involved in inflammation and oxidative stress. The significance of serum IL-33 levels on the prognosis of patients with intracerebral hemorrhage (ICH) has not been well studied. The purpose of this study is to determine whether there is a relationship between the serum IL-33 level and the prognosis of patients with ICH upon admission.

Methods

A total of 402 patients with confirmed ICH were included in this study. Their demographic data, medical history, laboratory data, imaging data, and clinical scores on admission were collected. At the same time, enzyme-linked immunoassay (ELISA) was used to detect the serum IL-33 levels of patients. The prognosis of patients was evaluated by mRS scale after 3 months, and mRS > 2 was defined as poor prognosis.

Results

Among 402 patients with ICH, the number of patients with good prognosis and poor prognosis after 3 months was 148 and 254, respectively. Compared with the ICH group with poor prognosis, the ICH group with good prognosis had lower baseline NHISS scores (p = 0.039) and hematoma volume (p = 0.025) and higher GCS scores (p < 0.001) and serum IL-33 levels (p < 0.001). The results of linear correlation analysis showed that serum IL-33 levels were significantly negatively correlated with baseline NHISS scores (r = −0.224, p = 0.033) and hematoma volume (r = −0.253, p = 0.046) but were significantly positively correlated with baseline GCS scores (r = 0.296, p = 0.020). The receiver operating characteristic curve (ROC) analysis showed that the sensitivity and specificity of serum IL-33 level in evaluating the prognosis of ICH were 72.1% and 74.3%, respectively. A cut-off value of serum IL-33 level < 109.3 pg/mL may indicate a poor prognosis for ICH.

Conclusions

Serum IL-33 level on admission may be a prognostic indicator of ICH, and its underlying mechanism needs further study.

Serum ICAM-1 as a Predictor of Prognosis in Patients with Acute Ischemic Stroke

Objective

Inflammation is one of the key mechanisms involved in functional impairment after stroke. Intercellular adhesion molecule-1 (ICAM-1) is an important inflammatory molecule in the body. The purpose of our study was to determine the correlation between ICAM-1 and the prognosis of acute ischemic stroke (AIS).

Methods

286 AIS patients treated at Beijing Tiantan Hospital were continuously included in the study. The demographic data of the patients were collected, and the fasting blood within 24 hours of admission was collected to detect the clinical indicators. The functional prognosis was measured using the modified Rankin Scale (mRS) 3 months after stroke. The poor prognosis is defined as mRS ≥ 3. The enzyme-linked immunosorbent assay (ELISA) was used to determine the serum ICAM-1 levels.

Results

The serum ICAM-1 levels of patients with poor prognosis were significantly higher than that of patients with good prognosis (144.2 ± 14.8 vs 117.5 ± 12.1 pg/ml). Receiver operating characteristic curve (ROC) analysis showed that the sensitivity and specificity of serum ICAM-1 for predicting the prognosis of AIS were 74% and 76%, respectively. In logistic regression analysis, the serum ICAM-1 level is still an independent predictor of poor prognosis (odds ratio [OR]: 0.52; 95% confidence interval [CI]: 0.318-0.839).

Conclusions

Higher serum ICAM-1 levels on admission in AIS patients might increase the risk of poor prognosis.

The Relationship between Serum Amyloid A Level and Cognitive Dysfunction in Patients with Vascular Dementia: Preliminary Findings

OBJECTIVE

This study was aimed at investigating the relationship between serum amyloid A (SAA) levels and cognitive dysfunction in patients with vascular dementia (VAD).

METHODS

Using cross-sectional research methods, 146 patients with VAD were selected as the VAD group and 70 normal people were selected as the NC group. Upon admission, the clinical and biochemical characteristics of the two groups of study subjects were collected, and the MMSE scale was used to assess cognitive function. A sandwich enzyme-linked immunosorbent assay was used to detect SAA levels.

RESULTS

There was no significant difference in clinical data and biochemical characteristics in the VAD group (p > 0.05). Compared with the VAD group, the NC group has a higher level of education (p < 0.05). The SAA level of the VAD group was higher than that of the NC group, and there was a significant difference (p < 0.05). Spearman correlation analysis showed that SAA and MMSE in the VAD group were negatively correlated. Further multiple regression analysis showed that the serum amyloid A level is an independent risk factor for cognitive dysfunction in VAD patients.

CONCLUSION

The level of SAA in VAD patients is significantly increased, which can be used as a potential peripheral blood marker to predict cognitive impairment in VAD patients.

Repressor Element 1 Silencing Transcription Factor (REST) Governs Microglia-Like BV2 Cell Migration via Progranulin (PGRN)

Microglia activation contributes to Alzheimer's disease (AD) etiology, and microglia migration is a fundamental function during microglia activation. The repressor element-1 silencing transcription factor (REST), a powerful transcriptional factor, was found to play a neuroprotective role in AD. Despite its possible role in disease progression, little is known about whether REST participates in microglia migration. In this study, we aimed to explore the function of REST and its molecular basis during microglia migration under Aβ 1-42-treated pathological conditions. When treated by Aβ 1-42 REST was upregulated through JAK2/STAT3 signal pathway in BV2 cells. And transwell coculture system was used to evaluate cell migration function of microglia-like BV2. Small interfering RNA (siRNA) targeting progranulin (PGRN) were delivered into BV2 cells, and results showed that PGRN functions to promote BV2 migration. REST expression was inhibited by sh-RNA, which induced BV2 cell migration obviously. On the contrary, REST was overexpressed by REST recombinant plasmid transfection, which repressed BV2 cell migration, indicating that REST may act as a repressor of cell migration. To more comprehensively examine the molecular basis, we analyzed the promoter sequence of PGRN and found that it has the potential binding site of REST. Moreover, knocking-down of REST can increase the expression of PGRN, which confirms the inhibiting effect of REST on PGRN expression. Further detection of double luciferase reporter gene also confirmed the inhibition of REST on the activity of PGRN promoter, indicating that REST may be an inhibitory transcription factor of PGRN which governs microglia-like BV2 cell migration. In conclusion, the present study demonstrates that transcription factor REST may act as a repressor of microglia migration through PGRN.

Increased Levels of Serum Neuregulin 1 Associated with Cognitive Impairment in Vascular Dementia

Objective

Neuregulin 1 (NRG 1) is a member of the epidermal growth factor (EGF) family and is believed to play an important role in neuroplasticity. However, the relationship between NRG 1 and vascular dementia (VaD) is poorly understood. The purpose of this study is to explore the correlation between neuregulin 1 and VaD. Patients and Methods. From October 2018 to September 2020, 93 VaD patients and 79 control populations who attended Liaocheng People's Hospital were included in the study. Baseline characteristics including age, gender, years of education, HDL, LDL, FBG, SBP, and DBP are collected. At the same time, peripheral blood was collected, and the concentration of serum NRG 1 was detected by enzyme-linked immunosorbent assay (ELISA). All research subjects received professional cognitive function assessment.

Results

A total of 93 VaD patients and 79 controls were enrolled. There was no significant difference in age, gender, years of education, HDL, LDL, FBG, SBP, and DBP between the two groups (p > 0.05). However, compared with the control group, VaD patients have lower MoCA and higher serum NRG 1 levels, and the difference is statistically significant (p < 0.001). The correlation analysis of MoCA and baseline characteristics showed that the MoCA score in VaD was significantly negatively correlated with serum NRG 1 (r = −0.374, p = 0.036). The results of multivariate regression showed that the MoCA score of VaD patients was only associated with NRG 1 (β = 0.258, p = 0.012).

Conclusions

The concentration of serum NRG 1 in VaD patients is significantly increased, which may be an independent risk factor for cognitive impairment in VaD patients.

Elevated Levels of Serum Neurofilament Light Chain Associated with Cognitive Impairment in Vascular Dementia

Objective

Vascular dementia (VaD) is a progressive neurodegenerative disease with cognitive decline caused by cerebrovascular factors. Despite the great progress made in the past decade, VaD still lacks effective treatments and peripheral blood biomarkers. In this study, we tested the level of peripheral blood neurofilament light chain (NfL) in VaD patients and explored its relationship with cognitive impairment.

Method

A total of 176 study subjects including 80 normal controls (NC) and 96 VaD patients were included in our study. Upon admission, we collected clinical and biochemical characteristics of all research subjects. We also evaluate the Montreal cognitive assessment scale (MoCA) scores of all subjects. The serum NfL level was measured by the single-molecule array (Simoa) method.

Results

The years of education in the NC group and VaD group were (11.65 ± 3.04) years and (10.53 ± 3.87) years, respectively. Compared with VaD patients, the NC group has a higher level of education (p = 0.037). Furthermore, the results of Simoa indicated that VaD subjects had higher serum NfL levels compared with the NC group [(8.49 ± 2.37) pg/ml vs. (19.26 ± 4.71) pg/ml, p < 0.001]. In terms of other clinical and biochemical characteristics, there was no significant difference between VaD and NC. The Spearman correlation analysis indicated that educational years have a significant positive correlation with MoCA scores (r = 0.238, p = 0.041), while age and serum NfL levels have a significantly negative correlation with MoCA scores (age: r = -0.213, p = 0.040; NfL: r = -0.395, p = 0.027). However, further multiple regression analysis showed that only serum NfL level might serve as an independent risk factor for cognitive decline in VaD (β = 0.317, p = 0.021).

Conclusion

The serum NfL levels in VaD subjects are significantly elevated, which may be used as a potential peripheral blood marker for predicting cognitive impairment in patients with VaD.

Association between serum NPTX2 and cognitive function in patients with vascular dementia

OBJECTIVE

Neuronal Pentraxin 2 (NPTX2) has recently been widely reported as a novel biomarker for Alzheimer's disease (AD), but its correlation with vascular dementia (VaD) has not been elucidated. This study aimed to explore the correlation between NPTX2 and the cognitive function of VaD patients.

METHODS

112 VaD patients and 76 healthy controls were included in the study. Upon admission, clinical baseline data for all subjects were collected. Serum NPTX2 levels were determined using enzyme-linked immunosorbent assay (ELISA). At the same time, the Montreal cognitive assessment (MoCA) scale was used to measure cognitive function. Multivariate regression analysis was used to determine the relationship between serum NPTX2 level and the cognitive function of VaD patients.

RESULTS

Compared with healthy controls, VaD patients had lower serum NPTX2 levels (p < .001). The results of Spearman's correlation analysis showed that serum NPTX2 levels in VaD patients were positively correlated with MoCA scores (r = .347, p = .042). The results of multivariate regression analysis showed that after adjusting for common risk factors, serum NPTX2 levels in VaD patients were still significantly associated with MoCA scores (β = 0.346, p = .039).

CONCLUSIONS

Serum NPTX2 level was independently associated with cognitive function in patients with VaD. Serum NPTX2 level may be a novel predictor for cognitive function in VaD.

Association of Serum FAM19A5 with Cognitive Impairment in Vascular Dementia

Objective

Family with sequence similarity 19 member A5 (FAM19A5), a novel chemokine-like peptide, is a secreted protein mainly expressed in the brain. FAM19A5 was recently found to be involved in a variety of neurological diseases; however, its correlation with vascular dementia (VaD) remains unclear. The aim of the study is to explore the association between serum FAM19A5 and cognitive impairment in subjects with VaD.

Method

136 VaD subjects and 81 normal controls were recruited in the study. Their demographic and clinical baseline data were collected on admission. All subjects received Mini-Mental State Examination (MMSE) evaluation, which was used to test their cognitive functions. A sandwich enzyme-linked immunosorbent assay (ELISA) was applied to detect the serum levels of FAM19A5.

Results

No significant differences were found between the two groups regarding the demographic and clinical baseline data (p > 0.05). The serum FAM19A5 levels were significantly higher compared to normal controls (p < 0.001). The Spearman correlation analysis indicated that serum FAM19A5 levels and MMSE scores have a significant negative correlation in VaD patients (r = −0.414, <0.001). Further multiple regression analysis indicated that serum FAM19A5 levels were independent risk predictors for cognitive functions in VaD (β = 0.419, p = 0.031).

Conclusion

The serum FAM19A5 level of VaD patients is significantly increased, which may serve as a biomarker to predict cognitive function of VaD.

TREM2 Overexpression Attenuates Cognitive Deficits in Experimental Models of Vascular Dementia

Neuroinflammation plays a prominent role in the pathogenesis of vascular dementia (VD). Triggering receptor expressed on myeloid cells 2 (TREM2) is a transmembrane receptor mainly expressed on microglia and has been known for its anti-inflammatory properties during immune response. However, data evaluating the effects of TREM2 in VD are lacking. Therefore, the present study is aimed at investigating the role of TREM2 in VD. In this study, the mouse model of VD was induced by transient bilateral common carotid artery occlusion (BCCAO). We compared the hippocampal gene and protein expressions of TREM2 between the VD mice and sham-operated mice at different time points. The TREM2 mRNA and protein expression levels in the VD mice were higher than those in the sham-operated mice. The cognitive deficits of VD mice were observed in the Morris water maze test. Interestingly, overexpression of TREM2 by intracerebroventricular injection of a lentiviral vector that encoded TREM2 (LV-TREM2) significantly improved the spatial learning and memory and attenuated the hippocampal neural loss in VD mice. Further mechanistic study revealed that overexpression of TREM2 significantly inhibited microglia M1 polarization by decreasing inducible nitric oxide synthase (iNOS) and proinflammatory cytokines expression levels and conversely enhanced microglia M2 polarization by increasing Arginase-1 (Arg-1) and anti-inflammatory cytokine expression levels. These results strongly suggest that TREM2 provides a protective effect in VD via modulating the phenotype of activated microglia and may serve as a novel potential therapeutic target for VD.