scholarly journals Cerebrovascular Injuries Induce Lymphatic Invasion into Brain Parenchyma to Guide Vascular Regeneration in Zebrafish

2018 ◽  
Author(s):  
Jingying Chen ◽  
Jianbo He ◽  
Qifen Yang ◽  
Yaoguang Zhang ◽  
Lingfei Luo
Keyword(s):  
Blood Vessels ◽  
Brain Edema ◽  
Interstitial Fluid ◽  
Molecular Mechanisms ◽  
Lymphatic Vessels ◽  
Lymphatic Invasion ◽  
Brain Parenchyma ◽  
Genetic Ablation ◽  
Vascular Regeneration ◽  
Promising Therapeutic Approach

SUMMARYDamage to regional cerebrovascular network and neuronal tissues occurs during acute cerebrovascular diseases, such as ischemic stroke. The promotion of vascular regeneration is the most promising therapeutic approach. To understand cellular and molecular mechanisms underlying brain vascular regeneration, we developed two zebrafish cerebrovascular injury models using genetic ablation and photochemical thrombosis. Although brain parenchyma is physiologically devoid of lymphatic vasculature, we found that cerebrovascular injuries induce rapid ingrowth of meningeal lymphatics into the injured parenchyma. The ingrown lymphatics on one hand become lumenized drain interstitial fluid to resolve brain edema, on the other hand act as “growing tracks” for nascent blood vessels. The ingrown lymphatic vessels undergo apoptosis and clearance after cerebrovascular regeneration. This study reveals a pathological function of meningeal lymphatics, through previously unexpected ingrowth into brain parenchyma and a newly identified lymphatic function as vascular “growing tracks”.HIGHLIGHTSCerebrovascular injuries induce lymphatic ingrowth into the injured brain parenchyma The ingrown lymphatics drain interstitial fluid to resolve brain edema Nascent blood vessels use the ingrown lymphatic vessels as “growing tracks” The ingrown lymphatic vessels undergo apoptosis after vascular regeneration completes

scholarly journals FACTORS INFLUENCING THE INTERMITTENT PASSAGE OF LOCKE'S SOLUTION INTO LIVING SKIN

1941 ◽  
Vol 73 (1) ◽  
pp. 85-108 ◽  
Author(s):  
Philip D. McMaster
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Atmospheric Pressure ◽  
Interstitial Fluid ◽  
Lymphatic Vessels ◽  
Intermittent Flow ◽  
Venous Obstruction ◽  
Factors Influencing ◽  
Interstitial Connective Tissue ◽  
Living Mouse

Minute amounts of Locke's or Tyrode's solution have been brought into contact with the interstitial connective tissue of the skin of the living mouse, at atmospheric pressure, in such a manner that the blood or lymphatic vessels are not entered directly. Under such circumstances these absorbable fluids enter the tissue spontaneously. Entrance is strikingly intermittent, not continuous, and so too when very slight pressures are brought to bear on the fluids (1). Hyperemia of the tissues, with accompanying dilatation of the blood vessels, increases the entrance of fluids at atmospheric pressure but it is still intermittent. By contrast, venous obstruction leads to intermittent backflow into the apparatus, but reflex hyperemia, following release of the obstruction, is attended by an increase of flow into the tissues in spite of the great reactive dilatation of vessels. The inflow is also intermittent. If the skin is deprived of circulation, fluid does not enter it at all at atmospheric pressure, though it moves in regularly and continuously if slight pressure is put upon it. Edema-forming fluids, described in the text, also enter in a continuous manner when forced into the skin of either living or dead animals. So too do serum and sperm oil. The findings indicate that the passage of interstitial fluid into the blood vessels may be intermittent under normal circumstances and its escape from them as well. The observed occurrence of intermittent flow in the blood vessels of several tissues (9, 15–25) will go far to account for the intermittent entrance of fluid into the skin.

scholarly journals Emerging Roles for VEGF-D in Human Disease

Biomolecules ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Steven Stacker ◽  
Marc Achen
Keyword(s):  
Blood Vessels ◽  
Human Disease ◽  
Molecular Mechanisms ◽  
Therapeutic Agent ◽  
Lymphatic Vessels ◽  
The Body ◽  
Vascular Endothelial ◽  
Animal Disease Models ◽  
Endothelial Growth Factor ◽  
Insight Into

Blood vessels and lymphatic vessels are located in many tissues and organs throughout the body, and play important roles in a wide variety of prevalent diseases in humans. Vascular endothelial growth factor-D (VEGF-D) is a secreted protein that can promote the remodeling of blood vessels and lymphatics in development and disease. Recent fundamental and translational studies have provided insight into the molecular mechanisms by which VEGF-D exerts its effects in human disease. Hence this protein is now of interest as a therapeutic and/or diagnostic target, or as a potential therapeutic agent, in a diversity of indications in cardiovascular medicine, cancer and the devastating pulmonary condition lymphangioleiomyomatosis. This has led to clinical trial programs to assess the effect of targeting VEGF-D signaling pathways, or delivering VEGF-D, in angina, cancer and ocular indications. This review summarizes our understanding of VEGF-D signaling in human disease, which is largely based on animal disease models and clinicopathological studies, and provides information about the outcomes of recent clinical trials testing agonists or antagonists of VEGF-D signaling.

scholarly journals Secondary lymphedema: Pathogenesis

2021 ◽  
Vol 3 ◽  
pp. 7-15
Author(s):  
Smitha Ancy Varghese
Keyword(s):  
Interstitial Fluid ◽  
Molecular Mechanisms ◽  
Subcutaneous Tissue ◽  
Lymphatic Vessels ◽  
Therapeutic Interventions ◽  
Elastic Fibers ◽  
Therapeutic Approaches ◽  
Secondary Lymphedema ◽  
Common Causes ◽  
The Common

Secondary lymphedema follows an acquired defect in the lymphatic system. The common causes leading to a defective lymphatic function include infection, inflammation, malignancy, trauma, obesity, immobility, and therapeutic interventions. Understanding the pathogenesis of lymphedema is of prime importance in offering effective treatment. The pathogenetic mechanisms such as lymphatic valvular insufficiency, obliteration/ disruption of lymphatic vessels, and decreased lymphatic contractility aggravate lymphatic hypertension and lymphstasis. Accumulation of lymph, interstitial fluid, proteins, and glycosaminoglycans within the skin and subcutaneous tissue eventually stimulates collagen production by fibroblasts, causes disruption of elastic fibers, and activates keratinocytes, fibroblasts, and adipocytes. These result in thickening of skin and cause fibrosis of subcutaneous tissue. However, the sequence of these pathomechanisms, their inter-relationship and progression vary depending on the specific etiology of the lymphedema. In this article, we discuss the possible cellular and molecular mechanisms involved in the pathogenesis. Further studies to delineate the exact sequence of pathogenic processes surrounding the primary triggering event can help to formulate tailored therapeutic approaches.

scholarly journals Loss of clusterin shifts amyloid deposition to the cerebrovasculature via disruption of perivascular drainage pathways

2017 ◽  
Vol 114 (33) ◽  
pp. E6962-E6971 ◽  
Author(s):  
Aleksandra M. Wojtas ◽  
Silvia S. Kang ◽  
Benjamin M. Olley ◽  
Maureen Gatherer ◽  
Mitsuru Shinohara ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Amyloid Β ◽  
Fold Increase ◽  
Brain Parenchyma ◽  
Amyloid Angiopathy ◽  
Clinical Complications ◽  
Perivascular Drainage

Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) peptide deposition in brain parenchyma as plaques and in cerebral blood vessels as cerebral amyloid angiopathy (CAA). CAA deposition leads to several clinical complications, including intracerebral hemorrhage. The underlying molecular mechanisms that regulate plaque and CAA deposition in the vast majority of sporadic AD patients remain unclear. The clusterin (CLU) gene is genetically associated with AD and CLU has been shown to alter aggregation, toxicity, and blood–brain barrier transport of Aβ, suggesting it might play a key role in regulating the balance between Aβ deposition and clearance in both brain and blood vessels. Here, we investigated the effect of CLU on Aβ pathology using the amyloid precursor protein/presenilin 1 (APP/PS1) mouse model of AD amyloidosis on a Clu+/+ or Clu−/− background. We found a marked decrease in plaque deposition in the brain parenchyma but an equally striking increase in CAA within the cerebrovasculature of APP/PS1;Clu−/− mice. Surprisingly, despite the several-fold increase in CAA levels, APP/PS1;Clu−/− mice had significantly less hemorrhage and inflammation. Mice lacking CLU had impaired clearance of Aβ in vivo and exogenously added CLU significantly prevented Aβ binding to isolated vessels ex vivo. These findings suggest that in the absence of CLU, Aβ clearance shifts to perivascular drainage pathways, resulting in fewer parenchymal plaques but more CAA because of loss of CLU chaperone activity, complicating the potential therapeutic targeting of CLU for AD.

scholarly journals Waste Clearance in the Brain

2021 ◽  
Vol 15 ◽  
Author(s):  
Jasleen Kaur ◽  
Lara M. Fahmy ◽  
Esmaeil Davoodi-Bojd ◽  
Li Zhang ◽  
Guangliang Ding ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Lymphatic Vessels ◽  
Brain Parenchyma ◽  
Perivascular Spaces ◽  
Future Directions ◽  
Relevant Role ◽  
Healthy Functioning ◽  
The Brain ◽  
Brain Homeostasis

Waste clearance (WC) is an essential process for brain homeostasis, which is required for the proper and healthy functioning of all cerebrovascular and parenchymal brain cells. This review features our current understanding of brain WC, both within and external to the brain parenchyma. We describe the interplay of the blood-brain barrier (BBB), interstitial fluid (ISF), and perivascular spaces within the brain parenchyma for brain WC directly into the blood and/or cerebrospinal fluid (CSF). We also discuss the relevant role of the CSF and its exit routes in mediating WC. Recent discoveries of the glymphatic system and meningeal lymphatic vessels, and their relevance to brain WC are highlighted. Controversies related to brain WC research and potential future directions are presented.

scholarly journals Inhibition of SHP2 ameliorates psoriasis by decreasing TLR7 endosome localization

2020 ◽  
Author(s):  
Yuyu Zhu ◽  
Fenli Shao ◽  
Wei Yan ◽  
Qiang Xu ◽  
Yang Sun
Keyword(s):  
Molecular Mechanisms ◽  
Mononuclear Cells ◽  
Tyrosine Phosphatase ◽  
Skin Inflammation ◽  
Peripheral Blood Mononuclear ◽  
Genetic Ablation ◽  
Src Homology 2 ◽  
Promising Therapeutic Approach ◽  
Src Homology ◽  
Src Homology 2 Domain

Psoriasis is a complex chronic inflammatory skin disease with unclear molecular mechanisms. Here, we identify Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) as a novel accelerator of psoriasis development. Both genetic ablation of SHP2 in macrophages and pharmacological inhibition of SHP2 prevents the development of psoriasis-like skin inflammation in an imiquimod-induced murine model of psoriasis. Mechanistically, SHP2 promotes the trafficking of Toll-like receptor 7 (TLR7) from Golgi to endosome through its interaction with and dephosphorylation of TLR7 at Tyr1024, which promotes the ubiquitination of TLR7 and psoriasis-like skin inflammation. Importantly, SHP2 allosteric inhibitor SHP099 reduces the expression of pro-inflammatory cytokines in peripheral blood mononuclear cells from human patients with psoriasis. Collectively, our findings identify SHP2 as a novel regulator of psoriasis and suggest that SHP2 inhibition may be a promising therapeutic approach for psoriatic patients.

scholarly journals Secondary lymphedema: Pathogenesis

2021 ◽  
Vol 3 ◽  
pp. 7-15
Author(s):  
Smitha Ancy Varghese
Keyword(s):  
Interstitial Fluid ◽  
Molecular Mechanisms ◽  
Subcutaneous Tissue ◽  
Lymphatic Vessels ◽  
Therapeutic Interventions ◽  
Elastic Fibers ◽  
Therapeutic Approaches ◽  
Secondary Lymphedema ◽  
Common Causes ◽  
The Common

Secondary lymphedema follows an acquired defect in the lymphatic system. The common causes leading to a defective lymphatic function include infection, inflammation, malignancy, trauma, obesity, immobility, and therapeutic interventions. Understanding the pathogenesis of lymphedema is of prime importance in offering effective treatment. The pathogenetic mechanisms such as lymphatic valvular insufficiency, obliteration/ disruption of lymphatic vessels, and decreased lymphatic contractility aggravate lymphatic hypertension and lymphstasis. Accumulation of lymph, interstitial fluid, proteins, and glycosaminoglycans within the skin and subcutaneous tissue eventually stimulates collagen production by fibroblasts, causes disruption of elastic fibers, and activates keratinocytes, fibroblasts, and adipocytes. These result in thickening of skin and cause fibrosis of subcutaneous tissue. However, the sequence of these pathomechanisms, their inter-relationship and progression vary depending on the specific etiology of the lymphedema. In this article, we discuss the possible cellular and molecular mechanisms involved in the pathogenesis. Further studies to delineate the exact sequence of pathogenic processes surrounding the primary triggering event can help to formulate tailored therapeutic approaches.

scholarly journals Cerebrovascular Injuries Induce Lymphatic Invasion into Brain Parenchyma to Guide Vascular Regeneration in Zebrafish

2019 ◽  
Vol 49 (5) ◽  
pp. 697-710.e5 ◽  
Author(s):  
Jingying Chen ◽  
Jianbo He ◽  
Rui Ni ◽  
Qifen Yang ◽  
Yaoguang Zhang ◽  
...  
Keyword(s):  
Lymphatic Invasion ◽  
Brain Parenchyma ◽  
Vascular Regeneration

scholarly journals Glymphatic System as a Gateway to Connect Neurodegeneration From Periphery to CNS

2021 ◽  
Vol 15 ◽  
Author(s):  
Gianfranco Natale ◽  
Fiona Limanaqi ◽  
Carla L. Busceti ◽  
Federica Mastroiacovo ◽  
Ferdinando Nicoletti ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Lymphatic Vessels ◽  
Normal Pressure ◽  
Lymphatic Drainage ◽  
Brain Parenchyma ◽  
Waste Products ◽  
Pathological Conditions ◽  
The Central Nervous System ◽  
Glymphatic Pathway ◽  
The Brain

The classic concept of the absence of lymphatic vessels in the central nervous system (CNS), suggesting the immune privilege of the brain in spite of its high metabolic rate, was predominant until recent times. On the other hand, this idea left questioned how cerebral interstitial fluid is cleared of waste products. It was generally thought that clearance depends on cerebrospinal fluid (CSF). Not long ago, an anatomically and functionally discrete paravascular space was revised to provide a pathway for the clearance of molecules drained within the interstitial space. According to this model, CSF enters the brain parenchyma along arterial paravascular spaces. Once mixed with interstitial fluid and solutes in a process mediated by aquaporin-4, CSF exits through the extracellular space along venous paravascular spaces, thus being removed from the brain. This process includes the participation of perivascular glial cells due to a sieving effect of their end-feet. Such draining space resembles the peripheral lymphatic system, therefore, the term “glymphatic” (glial-lymphatic) pathway has been coined. Specific studies focused on the potential role of the glymphatic pathway in healthy and pathological conditions, including neurodegenerative diseases. This mainly concerns Alzheimer’s disease (AD), as well as hemorrhagic and ischemic neurovascular disorders; other acute degenerative processes, such as normal pressure hydrocephalus or traumatic brain injury are involved as well. Novel morphological and functional investigations also suggested alternative models to drain molecules through perivascular pathways, which enriched our insight of homeostatic processes within neural microenvironment. Under the light of these considerations, the present article aims to discuss recent findings and concepts on nervous lymphatic drainage and blood–brain barrier (BBB) in an attempt to understand how peripheral pathological conditions may be detrimental to the CNS, paving the way to neurodegeneration.

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