Meso-cortical pathway damage in cognition, apathy and gait in cerebral small vessel disease

Inhibition of Mitochondrial Oxidative Stress and Apoptosis in the Protection of Ginkgo biloba extract 50 Against Cognitive Impairment

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L., a traditional medicinal plant with a long history of use in China, has been widely employed to promote blood circulation, relieve asthma, and enhance memory. It is also used in the management of cardiovascular and cerebrovascular conditions in various traditional practices. Although Ginkgo biloba shows promise in improving cognitive function and vascular health, its specific efficacy and underlying mechanism in cerebral small vessel disease remain unclear.

AIM OF THE STUDY

Cerebral small vessel disease (CSVD), a leading cause of cognitive decline and dementia, currently lacks effective treatment options. As a new generation extract of Ginkgo biloba L., Ginkgo biloba extract 50 (GBE50) was developed to investigate its potential therapeutic effects on CSVD and the underlying mechanisms.

MATERIALS AND METHODS

The bilateral carotid artery stenosis (BCAS) model was established in mice using microcoils, followed by therapeutic intervention. Cognitive function was assessed via the Morris water maze and Y-maze tests, while motor activity was evaluated using the open-field test. White matter and neuronal damage were analyzed through MRI, Luxol Fast Blue staining, and Nissl staining. The blood-active ingredients of GBE50 were identified using UPLC-Q-TOF-MS. Network pharmacology was applied to predict potential therapeutic targets of GBE50 against CSVD, and molecular docking was conducted to evaluate the binding interactions between key compounds and related proteins. The predicted targets and pathways were further validated through reverse transcription quantitative PCR (RT-qPCR, Western blot, and biochemical assays).

RESULTS

GBE50 significantly improved cognitive impairment in BCAS mice. MRI and histological analyses confirmed that GBE50 alleviated white matter lesions and hippocampal neuronal loss. Twenty ingredients, including quercetin, kaempferol, and isorhamnetin, were identified in GBE50, with 80 potential therapeutic targets. Molecular docking revealed strong binding affinities between key GBE50 compounds and apoptosis-related proteins such as CASP3, CASP9, BAX, BCL-2, and Cytochrome c. Twenty key genes were also validated by RT-qPCR. BCAS induced oxidative stress, inflammation, and mitochondrial apoptosis-related gene expression, which were mitigated by GBE50. BCAS increased malondialdehyde (MDA) levels and the NADP+/NADPH ratio while decreasing superoxide dismutase (SOD), and these imbalances were reversed by GBE50. Expression of Cytochrome c, BAX, and CASP3 was elevated, whereas BCL-2 was reduced in BCAS mice, effects counteracted by GBE50.

CONCLUSIONS

GBE50 alleviates cognitive impairment, white matter lesions, and neuronal loss in CSVD, potentially by inhibiting mitochondrial oxidative stress and apoptosis.

Emerging non-invasive MRI techniques for glymphatic system assessment in neurodegenerative disease

The discovery of the glymphatic system has revolutionized our understanding of brain physiology, particularly in waste clearance and fluid dynamics within the central nervous system. This pathway, essential for nutrient distribution and waste removal, operates predominantly during sleep and has been implicated in neurodegenerative diseases like Alzheimer's and Parkinson's. Recent advances in non-invasive MRI techniques, including diffusion tensor imaging along the perivascular space (DTI-ALPS), perivascular space (PVS) analysis, and free water (FW) indices, have improved our ability to study glymphatic function and its alterations in disease states. This review discusses the glymphatic system's ultrastructure, physiology, and the latest imaging methods to assess this critical pathway. We highlight how these non-invasive MRI techniques can enhance the understanding of glymphatic function in health and disease, with a focus on neurodegenerative conditions. By integrating insights from current research, this review underscores the diagnostic and therapeutic implications of glymphatic dysfunction. Understanding these mechanisms can pave the way for novel strategies to enhance waste clearance and improve neurological health, offering potential benefits for early diagnosis and intervention in neurodegenerative diseases.

Imaging brain fluid dynamics and waste clearance involving perivascular spaces in cerebral small vessel disease

Cerebral small vessel disease (SVD) is recognized as a major vascular contributor to cognitive decline, ultimately leading to dementia and stroke. While the pathogenesis of SVD remains unclear, emerging evidence suggests that waste clearance involving perivascular space (PVS) - also known as the glymphatic system - dysfunction may play a role. Among SVD radiological markers, the increased presence of dilated PVS is recognized as a marker of waste clearance disruption. Recently developed neuroimaging methods have been proposed as indirect measures of brain fluid dynamics, but they currently lack formal validation. Here, we provide a comprehensive overview of the latest neuroimaging advancements for assessing brain fluid dynamics, including waste clearance involving PVS function in SVD. We review the mechanisms by which clearance dysfunction might contribute to SVD. Finally, we argue that robust, multimodal, and longitudinal studies are essential for understanding the waste clearance (involving PVS) function and for establishing a diagnostic gold standard. HIGHLIGHTS: The majority of PVS are not visible on MRI, making it crucial to understand how and why they become dilated. The origin of waste clearance involving PVS disruption in SVD may be multifactorial. The BBB and waste clearance (involving PVS) dysfunction likely affect each other, forming a vicious cycle, promoting further amyloid beta accumulation. Yet their direct association in humans over time remains to be studied. Comparative studies can aid in the standardization of methods for assessing waste clearance involving PVS function.

Reward Decision Network Disconnection in Poststroke Apathy: A Prospective Multimodality Imaging Study

Apathy is a common neuropsychiatric symptom following stroke, characterized by reduced goal-directed behavior. The reward decision network (RDN), which plays a crucial role in regulating goal-directed behaviors, is closely associated with apathy. However, the relationship between poststroke apathy (PSA) and RDN dysfunction remains unclear due to apathy heterogeneity, the confounding effect of depression and individual variability in lesion impacts. This study aims to dissect the heterogeneity of PSA and explore the link between lesion-induced RDN damage and PSA. We prospectively recruited 207 patients with acute ischemic infarction and 60 demographically matched healthy controls. Participants underwent neuroimaging and longitudinal neuropsychiatric assessments. To characterize PSA heterogeneity, we employed multivariate analysis and clustering algorithms based on whole-brain functional connectivity and clinical assessments to classify patients into different PSA biotypes. We embedded each patient's lesion into a structural connectome atlas to obtain white matter (WM) disconnection maps. On this basis, WM disconnection scores were calculated for each brain region to quantify lesion-induced WM damage. We employed the XGBoost model to predict PSA biotypes based on WM disconnection scores, comparing the performance of models focusing on RDN-specific versus whole-brain WM disconnection. Additionally, we explored WM damage patterns across different biotypes by comparing disconnection scores in critical brain regions. We identified four PSA biotypes with unique clinical trajectories and neurobiological underpinnings. Biotype 4 was characterized by persistent apathy with depressive symptoms. Biotype 2 showed persistent apathy. Biotype 3 was non-apathetic. Biotype 1 exhibited delayed-onset apathy. The XGBoost models, when focused on the RDN-specific WM disconnection, performed significantly better in predicting PSA biotypes compared to the whole-brain WM disconnection model (t(164.66) = 8.871, p < 0.001). Analysis of WM disconnection patterns revealed that Biotype 4 exhibited more extensive RDN damage in crucial regions, Biotype 1 had a unique pattern of damage in the anterior cingulate cortex (t(61) = 1.874, p = 0.032), and Biotype 2 had a unique pattern of damage in the orbitofrontal cortex (t(53)= 1.827, p = 0.036). This study dissected PSA heterogeneity and demonstrated that RDN damage is a critical factor in PSA variability. We found that lesion-induced WM disconnections in anterior cingulate cortex and orbitofrontal cortex can lead to delayed-onset and persistent apathy, respectively. Furthermore, our findings revealed that apathy not only has distinct pathogenic mechanisms, but also shares neurobiological substrates with depression.

Potential biomarkers for cerebral small vessel disease with cognitive impairment: a systematic review and meta-analysis

Cerebral small vessel disease (CSVD) is a common factor in age-related diseases such as stroke and dementia, and about half of dementia patients worldwide are caused by CSVD. CSVD-related cognitive impairment (CSVD-CI) affects more and more elderly people, resulting in economic losses and burdens on families and society. In recent years, circulating biomarkers have made breakthroughs and played an increasingly important role in the diagnosis, progression, and prognosis of CSVD-associated cognitive impairment, and are expected to be applied to the early clinical detection, diagnosis, and treatment of patients with cerebral small vessel disease. Through a systematic review and meta-analysis, this study aimed to assess the relationship between circulating factors and cognitive impairment associated with cerebral small vessel disease, especially the possibility of becoming the potential biomarkers for diagnosis. Articles published before November 2023 were searched in four databases, PubMed, Web of Science, Embase, and Cochrane Library, to identify all relevant studies reporting circulating markers in patients with CSVD. Twenty-nine articles out of 2,911 were finalized for this study. We meta-analyzed 2 or more articles that were jointly considered to be circulating biomarkers of CSVD-CI and summarized a total of 4 possible biomarkers: homocysteine (Hcy), high-sensitivity C-reactive protein (hs-CRP), lipoprotein-associated phospholipase A2 (Lp-PLA2), and neurofilament protein light chain (NfL). The results revealed that patients in the CSVD-related cognitive impairment group had significantly higher levels of Hcy and hs-CRP than those in the CSVD-without cognitive impairment group, whereas there was no statistically significant difference in Lp-PLA2 and NfL between the two groups. Therefore, Hcy, hs-CRP may be considered circulating markers of cognitive impairment associated with cerebral small vessel disease.

Artificial intelligence-assisted oculo-gait measurements for cognitive impairment in cerebral small vessel disease

INTRODUCTION

Oculomotor and gait dysfunctions are closely associated with cognition. However, oculo-gait patterns and their correlation with cognition in cerebral small vessel disease (CSVD) remain unclear.

METHODS

Patients with CSVD from a hospital-based cohort (n = 194) and individuals with presumed early CSVD from a community-based cohort (n = 319) were included. Oculo-gait patterns were measured using the artificial intelligence (AI) -assisted 'EyeKnow' eye-tracking and 'ReadyGo' motor evaluation systems. Multivariable linear and logistic regression models were employed to investigate the association between the oculo-gait parameters and cognition.

RESULTS

Anti-saccade accuracy, stride velocity, and swing velocity were significantly associated with cognition in both patients and community dwellers with CSVD, and could identify cognitive impairment in CSVD with moderate accuracy (area under the curve [AUC]: hospital cohort, 0.787; community cohort, 0.810) after adjusting for age and education.

DISCUSSION

The evaluation of oculo-gait features (anti-saccade accuracy, stride velocity, and swing velocity) may help screen cognitive impairment in CSVD.

HIGHLIGHTS

Oculo-gait features (lower anti-saccade accuracy, stride velocity, and swing velocity) were associated with cognitive impairment in cerebral small vessel disease (CSVD). Logistic model integrating the oculo-gait features, age, and education level moderately distinguished cognitive status in CSVD. Artificial intelligence-assisted oculomotor and gait measurements provide quick and accurate evaluation in hospital and community settings.