Assessing pulsatile waveforms of paravascular cerebrospinal fluid dynamics within the glymphatic pathways using dynamic diffusion-weighted imaging (dDWI)

NeuroImage, Год журнала: 2022, Номер 260, С. 119464 - 119464

Опубликована: Июль 12, 2022

Cerebrospinal fluid (CSF) in the paravascular spaces of surface arteries (sPVS) is a vital pathway brain waste clearance. Arterial pulsations may be driving force flow, but its pulsatile pattern remains poorly characterized, and no clinically practical method for measuring dynamics human available. In this work, we introduce an imaging quantification framework in-vivo non-invasive assessment sPVS. It used dynamic Diffusion-Weighted Imaging (dDWI) at lower b-values 150s/mm2 retrospective gating to detect slow flow CSF while suppressing fast adjacent arterial blood. The waveform over cardiac cycle was revealed by synchronizing measurements with heartbeat. A data-driven approach developed identify sPVS allow automatic whole-brain waveforms. We applied dDWI twenty-five participants aged 18-82 y/o. Results demonstrated that waveforms across showed explicit cardiac-cycle dependency, good agreement vascular pumping hypothesis. Furthermore, shape closely resembled pressure artery wall, suggesting tightly related wall mechanics. Finally, aging strong age effect, significantly wider systolic peak observed older relative younger participants. widening associated compromised compliance vessel stiffening brain. Overall, results demonstrate feasibility, reproducibility, sensitivity detecting Our preliminary data suggest age-related alterations pumping. With acquisition time under six minutes, can readily study normal physiological conditions cerebrovascular/neurodegenerative diseases.

Язык: Английский

---

Neuroimaging at 7 Tesla: a pictorial narrative review

Quantitative Imaging in Medicine and Surgery, Год журнала: 2022, Номер 12(6), С. 3406 - 3435

Опубликована: Март 28, 2022

Neuroimaging using the 7-Tesla (7T) human magnetic resonance (MR) system is rapidly gaining popularity after being approved for clinical use in European Union and USA. This trend same functional MR imaging (MRI). The primary advantages of 7T over lower fields are its higher signal-to-noise contrast-to-noise ratios, which provide high-resolution acquisitions better contrast, making it easier to detect lesions structural changes brain disorders. Another advantage capability measure a greater number neurochemicals by virtue increased spectral resolution. Many studies have been conducted visualize details white matter layers cortex hippocampus, subnucleus or regions putamen, globus pallidus, thalamus substantia nigra, small structures, such as subthalamic nucleus, habenula, perforating arteries, perivascular space, that difficult observe at field strengths. target disorders neuroimaging range from tumoral diseases vascular, neurodegenerative, psychiatric disorders, including Alzheimer's disease, Parkinson's multiple sclerosis, epilepsy, major depressive disorder, schizophrenia. spectroscopy has also used research because chemical shift separates overlapping peaks resolves more effectively than field. paper presents narrative review these topics an illustrative presentation images obtained 7T. We expect new biomarker various

Язык: Английский

---

The meningeal lymphatic vessels and the glymphatic system: Potential therapeutic targets in neurological disorders

Journal of Cerebral Blood Flow & Metabolism, Год журнала: 2022, Номер 42(8), С. 1364 - 1382

Опубликована: Апрель 28, 2022

The recent discovery of the meningeal lymphatic vessels (mLVs) and glymphatic pathways has challenged long-lasting dogma that central nervous system (CNS) lacks a therefore does not interact with peripheral immunity. This reshaped our understanding mechanisms underlying CNS drainage. Under normal conditions, close connection between mLVs enables metabolic waste removal, immune cell trafficking, surveillance. Dysfunction glymphatic-mLV can lead to toxic protein accumulation in brain, it contributes development series neurodegenerative disorders, such as Alzheimer’s Parkinson's diseases. identification precise cerebral transport routes is based mainly on indirect, invasive imaging animals, results cannot always be applied humans. Here we review functions evidence for its involvement some We focus emerging noninvasive techniques evaluate human their potential preclinical diagnosis prevention Potential strategies target order treat prevent neurological disorders are also discussed.

Язык: Английский

---

Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus

Fluids and Barriers of the CNS, Год журнала: 2024, Номер 21(1)

Опубликована: Июль 17, 2024

Abstract The principles of cerebrospinal fluid (CSF) production, circulation and outflow regulation volumes pressures in the normal brain are summarised. Abnormalities these aspects intracranial hypertension, ventriculomegaly hydrocephalus discussed. parenchyma has a cellular framework with interstitial (ISF) intervening spaces. Framework stress pressure ( ISFP ) combined provide total which, after allowing for gravity, normally equals intracerebral ICP gradients too small to measure. Fluid may differ from collapsed subarachnoid spaces when presses against meninges. determine movements. In adults, restricting CSF produces hypertension change very little, is called idiopathic (iIH). Raised iIH accompanied by increased venous sinus pressure, though which cause effect unclear. infants growing skulls, restriction leads head volumes. can arise due cerebral atrophy or, hydrocephalus, obstructions flow. non-communicating flow through or out ventricles somehow obstructed, whereas communicating obstruction somewhere between cisterna magna cranial sites outflow. When routes continued production be partially balanced via an oedematous periventricular layer perivascular secondary raised results obvious By contrast, more subtly obstructed seen (NPH), must reduced elsewhere, e.g. some NPH, where gait disturbance, dementia and/or urinary incontinence, functional deficits sometimes reversed shunting third ventriculostomy. Parenchymal shrinkage irreversible late stage loss but not occur early stages, whether exclusion otherwise. Further studies that needed explain development outlined.

Язык: Английский

---

Low-level blast exposure induces chronic vascular remodeling, perivascular astrocytic degeneration and vascular-associated neuroinflammation

Acta Neuropathologica Communications, Год журнала: 2021, Номер 9(1)

Опубликована: Окт. 15, 2021

Abstract Cerebral vascular injury as a consequence of blast-induced traumatic brain is primarily the result blast wave-induced mechanical disruptions within neurovascular unit. In rodent models injury, chronic degenerative processes are associated with development an age-dependent post-traumatic stress disorder-like phenotype. To investigate evolution changes, Long-Evans rats were blast-exposed (3 × 74.5 kPa) and their brains analyzed at different times post-exposure by X-ray microcomputed tomography, immunohistochemistry electron microscopy. On tomography scans, regional cerebral attenuation or occlusion was observed early 48 h post-blast, disorganization visible 6 weeks more accentuated 13 months post-blast. Progression late-onset pathology characterized detachment endothelial smooth muscle cellular elements from neuropil due to degeneration loss arteriolar perivascular astrocytes. Development this remodeling neuroinflammation increased levels matrix metalloproteinases (MMP-2 MMP-9), collagen type IV loss, microglial activation in affected vasculature. Blast-induced alterations unit should affect blood circulation, glymphatic flow intramural periarterial drainage, all which may contribute behavioral Our results also identify astrocytic potential target for therapies treat injury.

Язык: Английский

---

Evaluation of glymphatic-meningeal lymphatic system with intravenous gadolinium-based contrast-enhancement in cerebral small-vessel disease

European Radiology, Год журнала: 2023, Номер 33(9), С. 6096 - 6106

Опубликована: Июль 6, 2023

Язык: Английский

---

Assessment of the glymphatic function in children with attention-deficit/hyperactivity disorder

European Radiology, Год журнала: 2023, Номер 34(3), С. 1444 - 1452

Опубликована: Сен. 6, 2023

Язык: Английский

---

The Cerebrovascular Side of Plasticity: Microvascular Architecture across Health and Neurodegenerative and Vascular Diseases

Brain Sciences, Год журнала: 2024, Номер 14(10), С. 983 - 983

Опубликована: Сен. 28, 2024

The delivery of nutrients to the brain is provided by a 600 km network capillaries and microvessels. Indeed, highly energy demanding and, among total amount 100 billion neurons, each neuron located just 10–20 μm from capillary. This vascular also forms part blood–brain barrier (BBB), which maintains brain’s stable environment regulating chemical balance, immune cell transport, blocking toxins. Typically, microvascular endothelial cells (BMECs) have low turnover, indicating cerebrovascular structure. However, this structure can adapt significantly due development, aging, injury, or disease. Temporary neural activity changes are managed expansion contraction arterioles capillaries. Hypoxia leads significant remodeling architecture pathological been documented in aging neurodegenerative conditions. These often involve BMEC proliferation capillary segments, linked with local neuronal cognitive function. Cerebrovascular plasticity, especially arterioles, capillaries, venules, varies over different time scales health, diseases. Rapid cerebral blood flow (CBF) occur within seconds increased activity. Prolonged structure, influenced consistent environmental factors, take weeks. Development bring months years, aging-associated plasticity improved exercise. Injuries cause rapid damage but be repaired weeks months, while diseases slow, varied years. In addition, if animal models may provide useful dynamic vivo information about humans more complex investigate hypothesis glymphatic system together Magnetic Resonance Imaging (MRI) techniques could clues future.

Язык: Английский

---

Diffusion Tensor Imaging Along Perivascular Spaces (DTI-ALPS) to Assess Effects of Age, Sex, and Head Size on Interstitial Fluid Dynamics in Healthy Subjects

Journal of Alzheimer s Disease Reports, Год журнала: 2024, Номер 8(1), С. 355 - 361

Опубликована: Фев. 20, 2024

Diffusion tensor imaging along perivascular spaces (DTI-ALPS) is a novel MRI method for assessing brain interstitial fluid dynamics, potentially indexing glymphatic function. Failed clearance implicated in Alzheimer’s disease (AD) pathophysiology. We assessed the contribution of age and female sex (strong AD risk factors) to DTI-ALPS index healthy subjects. also first time effect head size. In accord with prior studies, we show reduced aging, men compared women. However, size may be major contributing factor this counterintuitive difference.

Язык: Английский

---

Cannabidiol Alleviates Neurological Deficits After Traumatic Brain Injury by Improving Intracranial Lymphatic Drainage

Journal of Neurotrauma, Год журнала: 2024, Номер 41(15-16), С. e2009 - e2025

Опубликована: Март 30, 2024

Traumatic brain injury (TBI) persists as a substantial clinical dilemma, largely because of the absence effective treatments. This challenge is exacerbated by hindered clearance intracranial metabolic byproducts and continual accrual deleterious proteins. The glymphatic system (GS) meningeal lymphatic vessels (MLVs), key elements network, play critical roles in harmful substances. Cannabidiol (CBD) has shown promise reducing metabolite overload bolstering cognitive performance various neurodegenerative diseases. precise mechanisms attributing to its beneficial effects TBI scenarios, however, are yet be distinctly understood. Utilizing fluid percussion paradigm, our research adopted multifaceted approach, encompassing behavioral testing, immunofluorescence immunohistochemical analyses, laser speckle imaging, western blot techniques, bilateral cervical efferent ligation. methodology aimed discern influence CBD on both neurological outcomes murine model. We observed that administration notably ameliorated motor, memory, functions, concurrently with significant reduction concentration phosphorylated tau protein amyloid-β. In addition, expedited turnover elimination tracers, increased cerebral blood flow, enhanced efficacy fluorescent tracer migration from MLVs deep lymph nodes (dCLNs). Remarkably, treatment also induced reversion aquaporin-4 (AQP-4) polarization curtailed neuroinflammatory indices. A pivotal discovery was surgical interruption conduits neck nullified CBD's positive contributions waste disposal improvement, anti-neuroinflammatory actions remained unaffected. These insights suggest may enhance clearance, potentially via regulation system, thereby offering neurofunctional prognostic improvement models. Our findings underscore potential therapeutic applicability interventions, necessitating further comprehensive investigations validations substantiate these initial conclusions.

Язык: Английский

---