Prospects for Diminishing the Impact of Nonamyloid Small-Vessel Diseases of the Brain

Integrating clinical and biochemical markers: a novel nomogram for predicting lacunes in cerebral small vessel disease

Background

Lacunes, a characteristic feature of cerebral small vessel disease (CSVD), are critical public health concerns, especially in the aging population. Traditional neuroimaging techniques often fall short in early lacune detection, prompting the need for more precise predictive models.

Methods

In this retrospective study, 587 patients from the Neurology Department of the Affiliated Hospital of Hebei University who underwent cranial MRI were assessed. A nomogram for predicting lacune incidence was developed using LASSO regression and binary logistic regression analysis for variable selection. The nomogram's performance was quantitatively assessed using AUC-ROC, calibration plots, and decision curve analysis (DCA) in both training (n = 412) and testing (n = 175) cohorts.

Results

Independent predictors identified included age, gender, history of stroke, carotid atherosclerosis, hypertension, creatinine, and homocysteine levels. The nomogram showed an AUC-ROC of 0.814 (95% CI: 0.791-0.870) for the training set and 0.805 (95% CI: 0.782-0.843) for the testing set. Calibration and DCA corroborated the model's clinical value.

Conclusion

This study introduces a clinically useful nomogram, derived from binary logistic regression, that significantly enhances the prediction of lacunes in patients undergoing brain MRI for various indications, potentially advancing early diagnosis and intervention. While promising, its retrospective design and single-center context are limitations that warrant further research, including multi-center validation.

Epimedium flavonoids improve cerebral white matter lesions by inhibiting neuroinflammation and activating neurotrophic factor signal pathways in spontaneously hypertensive rats

Cerebral small vessel disease (CSVD) is one of the most common nervous system diseases. Hypertension and neuroinflammation are considered important risk factors for the development of CSVD and white matter (WM) lesions. We used the spontaneously hypertensive rat (SHR) as a model of early-onset CSVD and administered epimedium flavonoids (EF) for three months. The learning and memorization abilities were tested by new object recognition test. The pathological changes of WM were assessed using magnetic resonance imaging, transmission electron microscopy (TEM), Luxol fast blue and Black Gold staining. Oligodendrocytes (OLs) and myelin basic protein were detected by immunohistochemistry. The ultrastructure of the tight junctions was examined using TEM. Microglia and astrocytes were detected by immunofluorescence. RNA-seq was performed on the corpus callosum of rats. The results revealed that EF could significantly improve the learning and memory impairments in SHR, alleviate the injury and demyelination of WM nerve fibers, promote the differentiation of oligodendrocyte precursor cells (OPCs) into mature OLs, inhibit the activation of microglia and astrocytes, inhibit the expression of p38 MAPK/NF-κB p65/NLRP3 and inflammatory cytokines, and increase the expression of tight-junction related proteins ZO-1, occludin, and claudin-5. RNA-seq analysis showed that the neurotrophin signaling pathway played an important role in the disease. RT-qPCR and WB results showed that EF could regulate the expression of nerve growth factor and brain-derived neurotrophic factor and their downstream related proteins in the neurotrophin signaling pathway, which might explain the potential mechanism of EF's effects on the cognitive impairment and WM damage caused by hypertension.

Epidermal Growth Factor Receptors in Vascular Endothelial Cells Contribute to Functional Hyperemia in the Brain

Functional hyperemia-activity-dependent increases in local blood perfusion-underlies the on-demand delivery of blood to regions of enhanced neuronal activity, a process that is crucial for brain health. Importantly, functional hyperemia deficits have been linked to multiple dementia risk factors, including aging, chronic hypertension, and cerebral small vessel disease (cSVD). We previously reported crippled functional hyperemia in a mouse model of genetic cSVD that was likely caused by depletion of phosphatidylinositol 4,5-bisphosphate (PIP2) in capillary endothelial cells (EC) downstream of impaired epidermal growth factor receptor (EGFR) signaling. Here, using EC-specific EGFR-knockout (KO) mice, we directly examined the role of endothelial EGFR signaling in functional hyperemia, assessed by measuring increases in cerebral blood flow in response to contralateral whisker stimulation using laser Doppler flowmetry. Molecular characterizations showed that EGFR expression was dramatically decreased in freshly isolated capillaries from EC-EGFR-KO mice, as expected. Notably, whisker stimulation-induced functional hyperemia was significantly impaired in these mice, an effect that was rescued by administration of PIP2, but not by the EGFR ligand, HB-EGF. These data suggest that the deletion of the EGFR specifically in ECs attenuates functional hyperemia, likely via depleting PIP2 and subsequently incapacitating Kir2.1 channel functionality in capillary ECs. Thus, our study underscores the role of endothelial EGFR signaling in functional hyperemia of the brain.

Prevalence and Risk Factors of Cerebral Small Vessel Disease from a Population-Based Cohort in China

INTRODUCTION

Cerebral small vessel disease (CSVD) is a significant burden of morbidity and mortality among elderly people around the world. Epidemiological data with complete CSVD evaluations and a large sample size in the general population are still limited.

METHODS

Community-dwelling residents in Lishui city in China from the cross-sectional survey of the Polyvascular Evaluation for Cognitive Impairment and Vascular Events (PRECISE) study were included in this study from 2017 to 2019. All participants underwent 3 Tesla brain magnetic resonance images to assess CSVD imaging markers. Demographic and risk factor data were collected. The general and age-specific prevalence of lacune, confluent white matter hyperintensity (WMH), moderate-severe enlarged perivascular spaces (EPVS), cerebral microbleed (CMB), and total CSVD score (an ordinal scale from 0 to 4, counting the presence of four imaging markers of CSVD) was evaluated. Associations between vascular risk factors and these markers were analyzed by multivariable logistic regression.

RESULTS

A total of 3,063 participants were enrolled. The mean age was 61.2 years and 46.5% were men. The most prevalent CSVD marker was confluent WMH (16.7%), followed by CMB (10.2%), moderate-severe EPVS in the basal ganglia (BG-EPVS) (9.8%), and lacune (5.6%). 30.5% of the participants have at least one of the four markers (total CSVD score ≥1 points). The prevalence of CSVD markers increases as age increases. Age and hypertension were independent risk factors for four CSVD markers and the total CSVD score.

CONCLUSIONS

In this Chinese cohort with community-based adults aged 50-75 years, our findings showed a prevalence of 30.5% for CSVD. The most prevalent CSVD marker was confluent WMH, followed by CMB, moderate-severe BG-EPVS, and lacune. The risk factors for CSVD must be strictly screened and controlled in adults living in the community.

Negative correlation between serum pyruvate kinase M2 and cognitive function in patients with cerebral small vessel disease

OBJECTIVE

Cerebral small vessel disease (CSVD) is one of the main contributing factors to vascular cognitive impairment (VCI), with an increasing incidence rate. However, the genesis of CSVD cognitive impairment remains unknown. Inflammation and metabolic disorders are considered important pathogenesis of CSVD. In addition to acting as the key regulator of aerobic glycolysis, pyruvate kinase muscle isozyme 2 (PKM2) is a proinflammatory mediator transcriptional activator that can promote an inflammatory response. This study explored whether serum PKM2 is associated with cognitive impairment in CSVD patients.

METHODS

The demographic data, history of risk factors, laboratory data, and cognitive function scale assessment of 219 CSVD patients were analyzed, and the correlation between the CSVD clinical data and neuroimaging parameters with serum PKM2 was further explored. The serum PKM2 level was determined by enzyme-linked immunosorbent assay using the collected serum samples. Insulin resistance (IR) was assessed with reference to the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). HOMA-IR was calculated using the formula HOMA-IR = fasting plasma glucose (FPG, mmol/L) × fasting insulin (FINS, μU/mL)/22.5. A binomial logistic regression model was referred to infer the risk factors for VCI, and the ability of serum PKM2 to diagnose VCI was assessed by using a ROC curve.

RESULTS

Serum PKM2 level was positively correlated with HOMA-IR (r = 0.206, P = 0.002), negatively correlated with MMSE and MOCA on the cognitive scale in CSVD patients, and higher in CSVD patients with white matter hyperintensities (WMH) (P < 0.001). When compared with patients without cognitive impairment, the serum PKM2 levels were elevated in cases with suspected dementia, mild dementia, mild to moderate dementia, and moderate to severe dementia, and the differences were statistically significant (P < 0.05). Serum PKM2 levels were correlated with cognitive screening test scores in CSVD.

CONCLUSION

The present findings indicated that the serum PKM2 level was positively correlated with HOMA-IR, WMH, and enlarged perivascular spaces and negatively correlated with cognitive function in CSVD patients.

Active immunotherapy reduces NOTCH3 deposition in brain capillaries in a CADASIL mouse model

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of familial small vessel disease; no preventive or curative therapy is available. CADASIL is caused by mutations in the NOTCH3 gene, resulting in a mutated NOTCH3 receptor, with aggregation of the NOTCH3 extracellular domain (ECD) around vascular smooth muscle cells. In this study, we have developed a novel active immunization therapy specifically targeting CADASIL-like aggregated NOTCH3 ECD. Immunizing CADASIL TgN3R182C¹⁵⁰ mice with aggregates composed of CADASIL-R133C mutated and wild-type EGF_1-5 repeats for a total of 4 months resulted in a marked reduction (38-48%) in NOTCH3 deposition around brain capillaries, increased microglia activation and lowered serum levels of NOTCH3 ECD. Active immunization did not impact body weight, general behavior, the number and integrity of vascular smooth muscle cells in the retina, neuronal survival, or inflammation or the renal system, suggesting that the therapy is tolerable. This is the first therapeutic study reporting a successful reduction of NOTCH3 accumulation in a CADASIL mouse model supporting further development towards clinical application for the benefit of CADASIL patients.

CD8+ T cells induce interferon-responsive oligodendrocytes and microglia in white matter aging

A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. In the present study, we found age-related alterations of oligodendrocyte cell state with a reduction in total oligodendrocyte density in aging murine white matter. Using single-cell RNA-sequencing, we identified interferon (IFN)-responsive oligodendrocytes, which localize in proximity to CD8+ T cells in aging white matter. Absence of functional lymphocytes decreased the number of IFN-responsive oligodendrocytes and rescued oligodendrocyte loss, whereas T-cell checkpoint inhibition worsened the aging response. In addition, we identified a subpopulation of lymphocyte-dependent, IFN-responsive microglia in the vicinity of the CD8+ T cells in aging white matter. In summary, we provide evidence that CD8+ T-cell-induced, IFN-responsive oligodendrocytes and microglia are important modifiers of white matter aging.

Perspectives on Cognitive Phenotypes and Models of Vascular Disease

Clinical investigations have established that vascular-associated medical conditions are significant risk factors for various kinds of dementia. And yet, we are unable to associate certain types of vascular deficiencies with specific cognitive impairments. The reasons for this are many, not the least of which are that most vascular disorders are multi-factorial and the development of vascular dementia in humans is often a multi-year or multi-decade progression. To better study vascular disease and its underlying causes, the National Heart, Lung, and Blood Institute of the National Institutes of Health has invested considerable resources in the development of animal models that recapitulate various aspects of human vascular disease. Many of these models, mainly in the mouse, are based on genetic mutations, frequently using single-gene mutations to examine the role of specific proteins in vascular function. These models could serve as useful tools for understanding the association of specific vascular signaling pathways with specific neurological and cognitive impairments related to dementia. To advance the state of the vascular dementia field and improve the information sharing between the vascular biology and neurobehavioral research communities, National Heart, Lung, and Blood Institute convened a workshop to bring in scientists from these knowledge domains to discuss the potential utility of establishing a comprehensive phenotypic cognitive assessment of a selected set of existing mouse models, representative of the spectrum of vascular disorders, with particular attention focused on age, sex, and rigor and reproducibility. The workshop highlighted the potential of associating well-characterized vascular disease models, with validated cognitive outcomes, that can be used to link specific vascular signaling pathways with specific cognitive and neurobehavioral deficits.

A Novel Rodent Model of Hypertensive Cerebral Small Vessel Disease with White Matter Hyperintensities and Peripheral Oxidative Stress

Cerebral small vessel disease (CSVD) is the second most common cause of stroke and a major contributor to dementia. Manifestations of CSVD include cerebral microbleeds, intracerebral hemorrhages (ICH), lacunar infarcts, white matter hyperintensities (WMH) and enlarged perivascular spaces. Chronic hypertensive models have been found to reproduce most key features of the disease. Nevertheless, no animal models have been identified to reflect all different aspects of the human disease. Here, we described a novel model for CSVD using salt-sensitive ‘Sabra’ hypertension-prone rats (SBH/y), which display chronic hypertension and enhanced peripheral oxidative stress. SBH/y rats were either administered deoxycorticosteroid acetate (DOCA) (referred to as SBH/y-DOCA rats) or sham-operated and provided with 1% NaCl in drinking water. Rats underwent neurological assessment and behavioral testing, followed by ex vivo MRI and biochemical and histological analyses. SBH/y-DOCA rats show a neurological decline and cognitive impairment and present multiple cerebrovascular pathologies associated with CSVD, such as ICH, lacunes, enlarged perivascular spaces, blood vessel stenosis, BBB permeability and inflammation. Remarkably, SBH/y-DOCA rats show severe white matter pathology as well as WMH, which are rarely reported in commonly used models. Our model may serve as a novel platform for further understanding the mechanisms underlying CSVD and for testing novel therapeutics.

Notch signaling pathway: architecture, disease, and therapeutics

The NOTCH gene was identified approximately 110 years ago. Classical studies have revealed that NOTCH signaling is an evolutionarily conserved pathway. NOTCH receptors undergo three cleavages and translocate into the nucleus to regulate the transcription of target genes. NOTCH signaling deeply participates in the development and homeostasis of multiple tissues and organs, the aberration of which results in cancerous and noncancerous diseases. However, recent studies indicate that the outcomes of NOTCH signaling are changeable and highly dependent on context. In terms of cancers, NOTCH signaling can both promote and inhibit tumor development in various types of cancer. The overall performance of NOTCH-targeted therapies in clinical trials has failed to meet expectations. Additionally, NOTCH mutation has been proposed as a predictive biomarker for immune checkpoint blockade therapy in many cancers. Collectively, the NOTCH pathway needs to be integrally assessed with new perspectives to inspire discoveries and applications. In this review, we focus on both classical and the latest findings related to NOTCH signaling to illustrate the history, architecture, regulatory mechanisms, contributions to physiological development, related diseases, and therapeutic applications of the NOTCH pathway. The contributions of NOTCH signaling to the tumor immune microenvironment and cancer immunotherapy are also highlighted. We hope this review will help not only beginners but also experts to systematically and thoroughly understand the NOTCH signaling pathway.

Differential restoration of functional hyperemia by antihypertensive drug classes in hypertension-related cerebral small vessel disease

Dementia resulting from small vessel diseases (SVDs) of the brain is an emerging epidemic for which there is no treatment. Hypertension is the major risk factor for SVDs, but how hypertension damages the brain microcirculation is unclear. Here, we show that chronic hypertension in a mouse model progressively disrupts on-demand delivery of blood to metabolically active areas of the brain (functional hyperemia) through diminished activity of the capillary endothelial cell inward-rectifier potassium channel, Kir2.1. Despite similar efficacy in reducing blood pressure, amlodipine, a voltage-dependent calcium-channel blocker, prevented hypertension-related damage to functional hyperemia whereas losartan, an angiotensin II type 1 receptor blocker, did not. We attribute this drug class effect to losartan-induced aldosterone breakthrough, a phenomenon triggered by pharmacological interruption of the renin-angiotensin pathway leading to elevated plasma aldosterone levels. This hypothesis is supported by the finding that combining losartan with the aldosterone receptor antagonist eplerenone prevented the hypertension-related decline in functional hyperemia. Collectively, these data suggest Kir2.1 as a possible therapeutic target in vascular dementia and indicate that concurrent mineralocorticoid aldosterone receptor blockade may aid in protecting against late-life cognitive decline in hypertensive patients treated with angiotensin II type 1 receptor blockers.