scholarly journals Toward Minimalistic Model of Cellular Volume Dynamics in Neurovascular Unit

Mathematics ◽  
2021 ◽  
Vol 9 (19) ◽  
pp. 2407
Author(s):  
Robert Loshkarev ◽  
Dmitry Postnov
Keyword(s):  
Extracellular Space ◽  
Dynamic Properties ◽  
Neurovascular Unit ◽  
Brain Parenchyma ◽  
Vital Role ◽  
Brain Health ◽  
Cellular Processes ◽  
The Brain ◽  
Cell Volumes ◽  
Space Volume

The neurovascular unit (NVU) concept denotes cells and their communication mechanisms that autoregulate blood supply in the brain parenchyma. Over the past two decades, it has become clear that besides its primary function, NVU is involved in many important processes associated with maintaining brain health and that altering the proportion of the extracellular space plays a vital role in this. While biologists have studied the process of cells swelling or shrinking, the consequences of the NVU’s operation are not well understood. In addition to direct quantitative modeling of cellular processes in the NVU, there is room for developing a minimalistic mathematical description, similar to how computational neuroscience operates with very simple models of neurons, which, however, capture the main features of dynamics. In this work, we have developed a minimalistic model of cell volumes regulation in the NVU. We based our model on the FitzHugh–Nagumo model with noise excitation and supplemented it with a variable extracellular space volume. We show that such a model acquires new dynamic properties in comparison with the traditional neuron model. To validate our approach, we adjusted the parameters of the minimalistic model so that its behavior fits the dynamics computed using the high-dimensional quantitative and biophysically relevant model. The results show that our model correctly describes the change in cell volume and intercellular space in the NVU.

scholarly journals Nanoparticle brain delivery: a guide to verification methods

Nanomedicine ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 409-432 ◽  
Author(s):  
Robert A Yokel
Keyword(s):  
Cerebrospinal Fluid ◽  
Extracellular Space ◽  
Brain Parenchyma ◽  
Brain Delivery ◽  
Peripheral Organ ◽  
Blood Brain ◽  
Verification Methods ◽  
Brain Parenchymal ◽  
And Function ◽  
The Brain

Many reports conclude nanoparticle (NP) brain entry based on bulk brain analysis. Bulk brain includes blood, cerebrospinal fluid and blood vessels within the brain contributing to the blood–brain and blood–cerebrospinal fluid barriers. Considering the brain as neurons, glia and their extracellular space (brain parenchyma), most studies did not show brain parenchymal NP entry. Blood–brain and blood–cerebrospinal fluid barriers anatomy and function are reviewed. Methods demonstrating brain parenchymal NP entry are presented. Results demonstrating bulk brain versus brain parenchymal entry are classified. Studies are reviewed, critiqued and classified to illustrate results demonstrating bulk brain versus parenchymal entry. Brain, blood and peripheral organ NP timecourses are compared and related to brain parenchymal entry evidence suggesting brain NP timecourse informs about brain parenchymal entry.

scholarly journals The Neurovascular Unit Dysfunction in Alzheimer’s Disease

2021 ◽  
Vol 22 (4) ◽  
pp. 2022 ◽  
Author(s):  
Luis O. Soto-Rojas ◽  
Mar Pacheco-Herrero ◽  
Paola A. Martínez-Gómez ◽  
B. Berenice Campa-Córdoba ◽  
Ricardo Apátiga-Pérez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurovascular Unit ◽  
Amyloid Β ◽  
Brain Parenchyma ◽  
Amyloid Angiopathy ◽  
Amyloid Β Peptide ◽  
Vascular Risk ◽  
Therapeutic Approaches ◽  
The Brain

Alzheimer’s disease (AD) is the most common neurodegenerative disease worldwide. Histopathologically, AD presents with two hallmarks: neurofibrillary tangles (NFTs), and aggregates of amyloid β peptide (Aβ) both in the brain parenchyma as neuritic plaques, and around blood vessels as cerebral amyloid angiopathy (CAA). According to the vascular hypothesis of AD, vascular risk factors can result in dysregulation of the neurovascular unit (NVU) and hypoxia. Hypoxia may reduce Aβ clearance from the brain and increase its production, leading to both parenchymal and vascular accumulation of Aβ. An increase in Aβ amplifies neuronal dysfunction, NFT formation, and accelerates neurodegeneration, resulting in dementia. In recent decades, therapeutic approaches have attempted to decrease the levels of abnormal Aβ or tau levels in the AD brain. However, several of these approaches have either been associated with an inappropriate immune response triggering inflammation, or have failed to improve cognition. Here, we review the pathogenesis and potential therapeutic targets associated with dysfunction of the NVU in AD.

scholarly journals Insoluble Vascular Amyloid Deposits Trigger Disruption of the Neurovascular Unit in Alzheimer’s Disease Brains

2021 ◽  
Vol 22 (7) ◽  
pp. 3654
Author(s):  
Luis O. Soto-Rojas ◽  
B. Berenice Campa-Córdoba ◽  
Charles R. Harrington ◽  
Andrés Salas-Casas ◽  
Mario Hernandes-Alejandro ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurovascular Unit ◽  
Amyloid Β ◽  
Brain Parenchyma ◽  
Amyloid Β Peptide ◽  
Cerebral Blood Vessels ◽  
Amyloid Deposits ◽  
Cellular Components ◽  
The Brain

Alzheimer’s disease (AD) is a neurodegenerative disease, characterized histopathologically by intra-neuronal tau-related lesions and by the accumulation of amyloid β-peptide (Aβ) in the brain parenchyma and around cerebral blood vessels. According to the vascular hypothesis of AD, an alteration in the neurovascular unit (NVU) could lead to Aβ vascular accumulation and promote neuronal dysfunction, accelerating neurodegeneration and dementia. To date, the effects of insoluble vascular Aβ deposits on the NVU and the blood–brain barrier (BBB) are unknown. In this study, we analyze different Aβ species and their association with the cells that make up the NVU. We evaluated post-mortem AD brain tissue. Multiple immunofluorescence assays were performed against different species of Aβ and the main elements that constitute the NVU. Our results showed that there are insoluble vascular deposits of both full-length and truncated Aβ species. Besides, insoluble aggregates are associated with a decrease in the phenotype of the cellular components that constitute the NVU and with BBB disruption. This approach could help identify new therapeutic targets against key molecules and receptors in the NVU that can prevent the accumulation of vascular fibrillar Aβ in AD.

scholarly journals Interactions between Amyloid-Β Proteins and Human Brain Pericytes: Implications for the Pathobiology of Alzheimer’s Disease

2020 ◽  
Vol 9 (5) ◽  
pp. 1490 ◽  
Author(s):  
Donald J. Alcendor
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurovascular Unit ◽  
Amyloid Β ◽  
Brain Parenchyma ◽  
Blood Retinal Barrier ◽  
Endothelin 1 ◽  
Brain Pericytes ◽  
Aging Populations ◽  
The Brain

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that is the most common cause of dementia, especially among aging populations. Despite advances in AD research, the underlying cause and the discovery of disease-modifying treatments have remained elusive. Two key features of AD pathology are the aberrant deposition of amyloid beta (amyloid-β or Aβ) proteins in the brain parenchyma and Aβ toxicity in brain pericytes of the neurovascular unit/blood–brain barrier (NVU/BBB). This toxicity induces oxidative stress in pericytes and leads to capillary constriction. The interaction between pericytes and Aβ proteins results in the release of endothelin-1 in the pericytes. Endothelin-1 interacts with ETA receptors to cause pericyte contraction. This pericyte-mediated constriction of brain capillaries can cause chronic hypoperfusion of the brain microvasculature, subsequently leading to the neurodegeneration and cognitive decline observed in AD patients. The interaction between Aβ proteins and brain pericytes is largely unknown and requires further investigation. This review provides an updated overview of the interaction between Aβ proteins with pericytes, one the most significant and often forgotten cellular components of the BBB and the inner blood–retinal barrier (IBRB). The IBRB has been shown to be a window into the central nervous system (CNS) that could allow the early diagnosis of AD pathology in the brain and the BBB using modern photonic imaging systems such as optical coherence tomography (OCT) and two-photon microscopy. In this review, I explore the regulation of Aβ proteins in the brain parenchyma, their role in AD pathobiology, and their association with pericyte function. This review discusses Aβ proteins and pericytes in the ocular compartment of AD patients as well as strategies to rescue or protect pericytes from the effects of Aβ proteins, or to replace them with healthy cells.

scholarly journals Dissecting the Crosstalk between Endothelial Mitochondrial Damage, Vascular Inflammation, and Neurodegeneration in Cerebral Amyloid Angiopathy and Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2903
Author(s):  
Rebecca M. Parodi-Rullán ◽  
Sabzali Javadov ◽  
Silvia Fossati
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebral Amyloid Angiopathy ◽  
Vascular Inflammation ◽  
Neurovascular Unit ◽  
Brain Parenchyma ◽  
Amyloid Angiopathy ◽  
Wide Range ◽  
Cerebral Amyloid ◽  
The Brain

Alzheimer’s disease (AD) is the most prevalent cause of dementia and is pathologically characterized by the presence of parenchymal senile plaques composed of amyloid β (Aβ) and intraneuronal neurofibrillary tangles of hyperphosphorylated tau protein. The accumulation of Aβ also occurs within the cerebral vasculature in over 80% of AD patients and in non-demented individuals, a condition called cerebral amyloid angiopathy (CAA). The development of CAA is associated with neurovascular dysfunction, blood–brain barrier (BBB) leakage, and persistent vascular- and neuro-inflammation, eventually leading to neurodegeneration. Although pathologically AD and CAA are well characterized diseases, the chronology of molecular changes that lead to their development is still unclear. Substantial evidence demonstrates defects in mitochondrial function in various cells of the neurovascular unit as well as in the brain parenchyma during the early stages of AD and CAA. Dysfunctional mitochondria release danger-associated molecular patterns (DAMPs) that activate a wide range of inflammatory pathways. In this review, we gather evidence to postulate a crucial role of the mitochondria, specifically of cerebral endothelial cells, as sensors and initiators of Aβ-induced vascular inflammation. The activated vasculature recruits circulating immune cells into the brain parenchyma, leading to the development of neuroinflammation and neurodegeneration in AD and CAA.

MiRNA-145 and Its Direct Downstream Targets in Digestive System Cancers: A Promising Therapeutic Target

2020 ◽  
Vol 26 ◽  
Author(s):  
Yini Ma ◽  
Xiu Cao ◽  
Guojuan Shi ◽  
Tianlu Shi
Keyword(s):  
Digestive System ◽  
Target Genes ◽  
Malignant Neoplasm ◽  
Vital Role ◽  
Diagnostic Biomarkers ◽  
Cellular Processes ◽  
Promising Therapeutic Target ◽  
Direct Target ◽  
Potential Strategy

: MicroRNAs (miRNAs) play a vital role in the onset and development of many diseases, including cancers. Emerging evidence shows that numerous miRNAs have the potential to be used as diagnostic biomarkers for cancers, and miRNA-based therapy may be a promising therapy for the treatment of malignant neoplasm. MicroRNA-145 (miR-145) has been considered to play certain roles in various cellular processes, such as proliferation, differentiation and apoptosis, via modulating expression of direct target genes. Recent reports show that miR-145 participates in the progression of digestive system cancers, and plays crucial and novel roles for cancer treatment. In this review, we summarize the recent knowledge concerning the function of miR-145 and its direct targets in digestive system cancers. We discuss the potential role of miR-145 as valuable biomarkers for digestive system cancers and how miR-145 regulates these digestive system cancers via different targets to explore the potential strategy of targeting miR-145.

scholarly journals Mesenchymal Stem Cell Derived Extracellular Vesicles for Repairing the Neurovascular Unit after Ischemic Stroke

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 767
Author(s):  
Courtney Davis ◽  
Sean I. Savitz ◽  
Nikunj Satani
Keyword(s):  
Ischemic Stroke ◽  
Extracellular Vesicles ◽  
Neurovascular Unit ◽  
Culture Conditions ◽  
Therapeutic Effects ◽  
Stroke Treatment ◽  
Inflammatory Molecules ◽  
The Brain

Ischemic stroke is a debilitating disease and one of the leading causes of long-term disability. During the early phase after ischemic stroke, the blood-brain barrier (BBB) exhibits increased permeability and disruption, leading to an influx of immune cells and inflammatory molecules that exacerbate the damage to the brain tissue. Mesenchymal stem cells have been investigated as a promising therapy to improve the recovery after ischemic stroke. The therapeutic effects imparted by MSCs are mostly paracrine. Recently, the role of extracellular vesicles released by these MSCs have been studied as possible carriers of information to the brain. This review focuses on the potential of MSC derived EVs to repair the components of the neurovascular unit (NVU) controlling the BBB, in order to promote overall recovery from stroke. Here, we review the techniques for increasing the effectiveness of MSC-based therapeutics, such as improved homing capabilities, bioengineering protein expression, modified culture conditions, and customizing the contents of EVs. Combining multiple techniques targeting NVU repair may provide the basis for improved future stroke treatment paradigms.

scholarly journals Microglia in Neurodegenerative Events—An Initiator or a Significant Other?

2021 ◽  
Vol 22 (11) ◽  
pp. 5818
Author(s):  
Gaylia Jean Harry
Keyword(s):  
Neurovascular Unit ◽  
Cell Types ◽  
In Vitro Assays ◽  
Significant Other ◽  
Neurodegenerative Process ◽  
Target Sites ◽  
Systemic Factors ◽  
Injury And Repair ◽  
The Brain

A change in microglia structure, signaling, or function is commonly associated with neurodegeneration. This is evident in the patient population, animal models, and targeted in vitro assays. While there is a clear association, it is not evident that microglia serve as an initiator of neurodegeneration. Rather, the dynamics imply a close interaction between the various cell types and structures in the brain that orchestrate the injury and repair responses. Communication between microglia and neurons contributes to the physiological phenotype of microglia maintaining cells in a surveillance state and allows the cells to respond to events occurring in their environment. Interactions between microglia and astrocytes is not as well characterized, nor are interactions with other members of the neurovascular unit; however, given the influence of systemic factors on neuroinflammation and disease progression, such interactions likely represent significant contributes to any neurodegenerative process. In addition, they offer multiple target sites/processes by which environmental exposures could contribute to neurodegenerative disease. Thus, microglia at least play a role as a significant other with an equal partnership; however, claiming a role as an initiator of neurodegeneration remains somewhat controversial.

scholarly journals Macrophages and microglia: the cerberus of glioblastoma

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Alice Buonfiglioli ◽  
Dolores Hambardzumyan
Keyword(s):  
Tumor Cells ◽  
Innate Immune System ◽  
Tumor Heterogeneity ◽  
Expression Profiles ◽  
Brain Parenchyma ◽  
Innate Immune ◽  
Malignant Growth ◽  
Neoplastic Cells ◽  
Functional Roles ◽  
The Brain

AbstractGlioblastoma (GBM) is the most aggressive and deadliest of the primary brain tumors, characterized by malignant growth, invasion into the brain parenchyma, and resistance to therapy. GBM is a heterogeneous disease characterized by high degrees of both inter- and intra-tumor heterogeneity. Another layer of complexity arises from the unique brain microenvironment in which GBM develops and grows. The GBM microenvironment consists of neoplastic and non-neoplastic cells. The most abundant non-neoplastic cells are those of the innate immune system, called tumor-associated macrophages (TAMs). TAMs constitute up to 40% of the tumor mass and consist of both brain-resident microglia and bone marrow-derived myeloid cells from the periphery. Although genetically stable, TAMs can change their expression profiles based upon the signals that they receive from tumor cells; therefore, heterogeneity in GBM creates heterogeneity in TAMs. By interacting with tumor cells and with the other non-neoplastic cells in the tumor microenvironment, TAMs promote tumor progression. Here, we review the origin, heterogeneity, and functional roles of TAMs. In addition, we discuss the prospects of therapeutically targeting TAMs alone or in combination with standard or newly-emerging GBM targeting therapies.

scholarly journals The Role of Vitamin D as a Biomarker in Alzheimer’s Disease

2021 ◽  
Vol 11 (3) ◽  
pp. 334
Author(s):  
Giulia Bivona ◽  
Bruna Lo Sasso ◽  
Caterina Maria Gambino ◽  
Rosaria Vincenza Giglio ◽  
Concetta Scazzone ◽  
...  
Keyword(s):  
Vitamin D ◽  
Risk Factor ◽  
Cognitive Decline ◽  
Immune Cell ◽  
Response To Treatment ◽  
Cellular Processes ◽  
Vitamin D Levels ◽  
The Brain ◽  
Key Questions

Vitamin D and cognition is a popular association, which led to a remarkable body of literature data in the past 50 years. The brain can synthesize, catabolize, and receive Vitamin D, which has been proved to regulate many cellular processes in neurons and microglia. Vitamin D helps synaptic plasticity and neurotransmission in dopaminergic neural circuits and exerts anti-inflammatory and neuroprotective activities within the brain by reducing the synthesis of pro-inflammatory cytokines and the oxidative stress load. Further, Vitamin D action in the brain has been related to the clearance of amyloid plaques, which represent a feature of Alzheimer Disease (AD), by the immune cell. Based on these considerations, many studies have investigated the role of circulating Vitamin D levels in patients affected by a cognitive decline to assess Vitamin D’s eventual role as a biomarker or a risk factor in AD. An association between low Vitamin D levels and the onset and progression of AD has been reported, and some interventional studies to evaluate the role of Vitamin D in preventing AD onset have been performed. However, many pitfalls affected the studies available, including substantial discrepancies in the methods used and the lack of standardized data. Despite many studies, it remains unclear whether Vitamin D can have a role in cognitive decline and AD. This narrative review aims to answer two key questions: whether Vitamin D can be used as a reliable tool for diagnosing, predicting prognosis and response to treatment in AD patients, and whether it is a modifiable risk factor for preventing AD onset.

Sign in / Sign up

Export Citation Format

Share Document