Vasculocentric Axonal NfH in Small Vessel Disease

Fluid biomarkers of vascular cognitive Impairment: From vascular pathophysiology to potential clinical applications

Vascular cognitive impairment (VCI) refers to cognitive decline resulting from cerebrovascular pathology, affecting one or more cognitive domains. Chronic vascular risk factors and acute cerebrovascular events contribute significantly to this condition. Identifying fluid biomarkers indicative of vascular injury is crucial for early prevention, accurate diagnosis, and assessing treatment efficacy in VCI. Chronic vascular injury leads to arterial lesions, blood-brain barrier disruption, venous tortuosity and obstructed drainage, enlarged perivascular spaces, and impaired glymphatic drainage. This review explores biomarkers involved in VCI pathogenesis, including neurodegenerative proteins, inflammatory mediators, oxidative stress markers, metabolic byproducts, acute phase reactants, vasoactive neuropeptides, the cerebrospinal fluid/plasma albumin quotient, neurofilament light chain, circulating CD34 + cells, and miRNAs. Most biomarkers are derived from blood and cerebrospinal fluid, with the exception of 8-hydroxydeoxyguanosine, excreted in urine. Combining biomarkers from various fluid sources can enhance diagnostic accuracy for VCI. Given the interplay between blood buffering and renal excretion in biomarker production, we advocate for further research into urine-derived biomarkers. These may offer valuable insights for early detection of vascular changes and ultra-early prediction of VCI.

Review of the mechanism of infection induced cerebral small vessel disease

Cerebral small vessel disease (CSVD) refers to a group of pathological syndromes that affect the brain's microcirculation. These conditions involve damage to small arteries, arterioles, capillaries, venules, and small veins. Cerebrovascular risk factors, immunosenescence, and inflammatory responses contribute to the pathogenesis of cerebral small vessel disease. The global impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has drawn significant attention to chronic inflammation caused by infections. Research into the mechanisms by which infections induce CSVD has made continual advancements. It is imperative to reassess the importance of managing infections and the chronic inflammatory phase that follows, highlighting their critical role in the pathogenesis. Our focus encompasses SARS-CoV-2, Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), Zika Virus(ZIKV), Treponema pallidum, as well as the microbial communities within the gut and oral cavity. These pathogen infections and chronic inflammation can contribute to CSVD through mechanisms such as neuroinflammation, blood-brain barrier disruption, microthrombosis, and endothelial cell damage, thereby promoting the occurrence and progression of the disease. This highlights the need for detailed mechanistic research on CSVD associated with these pathogens. Furthermore, we hope that in the future, we will be able to devise targeted prevention and treatment strategies for CSVD based on the unique characteristics of the pathogenic mechanisms associated with various infections.

Serum neurofilament heavy chain predicts post-stroke cognitive impairment

Serum phosphorylation neurofilament heavy chain (p-NfH) is a marker of axonal injury, and previous research has shown an association between p-NfH and both Alzheimer's disease and frontotemporal dementia. However, there have been no reports on its relationship with post-stroke cognitive impairment (PSCI). The purpose of this study is to investigate whether p-NfH can serve as a predictive biomarker for PSCI following acute ischemic stroke (AIS). From July 2020 to September 2021, a total of 58 cases of first-time acute ischemic stroke (AIS) patients were admitted to the Department of Neurology in the Second Hospital of Hebei Medical University. Additionally, 30 healthy volunteers were randomly selected as the control group. Demographic data, medical history, NIHSS scores, cerebral infarction volume, Fazekas scores for white matter and the serum p-NfH were collected. Follow-up assessments were conducted at 6 and 12 months after AIS. Cognitive function was evaluated using a multi-domain cognitive assessment scale, and patients were categorized into the post-stroke cognitive impairment group (PSCI) and non-post-stroke cognitive impairment group (N-PSCI). Further stratification was done into the progression group (MoCA score decline) and stable group (MoCA score unchanged or improved) based on the difference in MoCA scores between 12 and 6 months. The serum p-NfH levels in the AIS group were significantly higher than those in the control group (p < 0.01). Additionally, p-NfH levels were positively correlated with NIHSS scores and infarct volume. Furthermore, AIS patients with moderate to severe cerebral white matter lesions (Fazekas score ≥ 2) showed higher p-NfH levels compared to AIS patients with no or mild white matter lesions (Fazekas score 0 or 1) (p < 0.01). The PSCI group demonstrated higher p-NfH levels compared to the N-PSCI group, even after accounting for variables such as age, education level, NIHSS, infarct volume, and Fazekas grading (OR = 1.06, 95% CI 1.004-1.11, p = 0.03). Furthermore, the progression group exhibited significantly elevated p-NfH levels in comparison to the stable group. The ROC curve analysis revealed that the ideal cutoff point for p-NfH was determined to be at 166.03 pg/ml. This cutoff point exhibited a sensitivity of 0.774 and a specificity of 0.926 (p < 0.01). Furthermore, the area under the curve was calculated to be 0.881 (95% CI 0.791-0.97, p < 0.01). Serum p-NfH is a potential biomarker for predicting PSCI. Further investigation should explore its potential as an indicator for timely cognitive intervention in stroke patients during follow-up.

Biomarkers Unveiling the Interplay of Mind, Nervous System, and Immunity

The field of psychoneuroimmunology has significantly expanded in the last few decades and so has our understanding of the bidirectional communications between the immune and central nervous systems (CNS). There is a preponderance of evidence supporting the fact that immunological pathways and neuroinflammation are involved in the pathophysiology of multiple neurological and mental health conditions. In this chapter, we have explored various neuroimmunological biomarkers involved in these pathways, responsible for developing and perpetuating different neuropsychiatric disorders. This chapter will examine inflammatory biomarkers and those associated with intestinal homeostasis, blood-brain barrier (BBB) permeability, glial cells, and neuronal injury. A range of tests has been developed to evaluate these markers, and we will also explore the existing methods currently employed for these techniques. Further studies of these inflammatory and neurological markers are needed to support their utility as biomarkers for diagnosis and prognosis and to inform treatment strategies for various neuropsychiatric disorders.

The promise of molecular science in brain health. What breakthroughs are anticipated in the next 20 years?

Brain health means optimal physiological brain function across the normal life-course. It encompasses not only healthy brain aging but also brain diseases, their diagnosis and treatment. In all these areas, molecular science has advanced our understanding. This multi-disciplinary review combines viewpoints from laboratory science, clinical medicine and the bioscience industry. First, we review the advances that molecular science has brought to brain health in the past twenty years. These include therapeutic antibodies for CNS diseases (multiple sclerosis, Alzheimer disease) and the dramatic introduction of RNA-targeted therapeutics. Second, we highlight areas where greater molecular understanding is needed. Salient examples are the relation of brain structure to cognitive symptoms, and molecular biomarkers for diagnosis, target discovery and testing of interventions. Finally, we speculate on aspects of molecular science that are likely to advance brain health in the next twenty years. These include: cell senescence and chronobiology; gene editing (notably, CRISPR) and RNA targeting (RNA interference, miRNA manipulation); brain-immune interactions; novel drug targets (AQP4, HIF1, Toll-like receptors); and novel chemistry to make new drugs (molecular machines, quantum molecular modelling and "click" chemistry). Early testing of the relationships between molecular pathways and clinical manifestations will drive much-needed breakthroughs in neurology and psychiatry.

Cerebral Small Vessel Disease, Hypertension, and Vascular Contributions to Cognitive Impairment and Dementia

Hypertension-associated cerebral small vessel disease is a common finding in older people. Strongly associated with age and hypertension, small vessel disease is found at autopsy in over 50% of people aged ≥65 years, with a spectrum of clinical manifestations. It is the main cause of lacunar stroke and a major source of vascular contributions to cognitive impairment and dementia. The brain areas affected are subcortical and periventricular white matter and deep gray nuclei. Neuropathological sequelae are diffuse white matter lesions (seen as white matter hyperintensities on T2-weighted magnetic resonance imaging), small ischemic foci (lacunes or microinfarcts), and less commonly, subcortical microhemorrhages. The most common form of cerebral small vessel disease is concentric, fibrotic thickening of small penetrating arteries (up to 300 microns outer diameter) termed arteriolosclerosis. Less common forms are small artery atheroma and lipohyalinosis (the lesions described by C. Miller Fisher adjacent to lacunes). Other microvascular lesions that are not reviewed here include cerebral amyloid angiopathy and venous collagenosis. Here, we review the epidemiology, neuropathology, clinical management, genetics, preclinical models, and pathogenesis of hypertensive small vessel disease. Knowledge gaps include initiating factors, molecular pathogenesis, relationships between arterial pathology and tissue damage, possible reversibility, pharmacological targets, and molecular biomarkers. Progress is anticipated from multicell transcriptomic and proteomic profiling, novel experimental models and further target-finding and interventional clinical studies.

The Neurovasculome: Key Roles in Brain Health and Cognitive Impairment: A Scientific Statement From the American Heart Association/American Stroke Association

BACKGROUND

Preservation of brain health has emerged as a leading public health priority for the aging world population. Advances in neurovascular biology have revealed an intricate relationship among brain cells, meninges, and the hematic and lymphatic vasculature (the neurovasculome) that is highly relevant to the maintenance of cognitive function. In this scientific statement, a multidisciplinary team of experts examines these advances, assesses their relevance to brain health and disease, identifies knowledge gaps, and provides future directions.

METHODS

Authors with relevant expertise were selected in accordance with the American Heart Association conflict-of-interest management policy. They were assigned topics pertaining to their areas of expertise, reviewed the literature, and summarized the available data.

RESULTS

The neurovasculome, composed of extracranial, intracranial, and meningeal vessels, as well as lymphatics and associated cells, subserves critical homeostatic functions vital for brain health. These include delivering O2 and nutrients through blood flow and regulating immune trafficking, as well as clearing pathogenic proteins through perivascular spaces and dural lymphatics. Single-cell omics technologies have unveiled an unprecedented molecular heterogeneity in the cellular components of the neurovasculome and have identified novel reciprocal interactions with brain cells. The evidence suggests a previously unappreciated diversity of the pathogenic mechanisms by which disruption of the neurovasculome contributes to cognitive dysfunction in neurovascular and neurodegenerative diseases, providing new opportunities for the prevention, recognition, and treatment of these conditions.

CONCLUSIONS

These advances shed new light on the symbiotic relationship between the brain and its vessels and promise to provide new diagnostic and therapeutic approaches for brain disorders associated with cognitive dysfunction.

The 2022 Lady Estelle Wolfson lectureship on neurofilaments

Neurofilament proteins (Nf) have been validated and established as a reliable body fluid biomarker for neurodegenerative pathology. This review covers seven Nf isoforms, Nf light (NfL), two splicing variants of Nf medium (NfM), two splicing variants of Nf heavy (NfH),α -internexin (INA) and peripherin (PRPH). The genetic and epigenetic aspects of Nf are discussed as relevant for neurodegenerative diseases and oncology. The comprehensive list of mutations for all Nf isoforms covers Amyotrophic Lateral Sclerosis, Charcot-Marie Tooth disease, Spinal muscular atrophy, Parkinson Disease and Lewy Body Dementia. Next, emphasis is given to the expanding field of post-translational modifications (PTM) of the Nf amino acid residues. Protein structural aspects are reviewed alongside PTMs causing neurodegenerative pathology and human autoimmunity. Molecular visualisations of NF PTMs, assembly and stoichiometry make use of Alphafold2 modelling. The implications for Nf function on the cellular level and axonal transport are discussed. Neurofilament aggregate formation and proteolytic breakdown are reviewed as relevant for biomarker tests and disease. Likewise, Nf stoichiometry is reviewed with regard to in vitro experiments and as a compensatory mechanism in neurodegeneration. The review of Nf across a spectrum of 87 diseases from all parts of medicine is followed by a critical appraisal of 33 meta-analyses on Nf body fluid levels. The review concludes with considerations for clinical trial design and an outlook for future research.