scholarly journals Blood-brain barrier, lymphatic clearance and recovery: Ariadne’s thread in labyrinths of hypothesis

Author(s):  
Oxana Semyachkina-Glushkovskaya ◽  
Dmitry Postnov ◽  
Jürgen Kurths

The peripheral lymphatic system plays a crucial role in the recovery mechanisms after many pathological changes, such as infection, trauma, vascular, or metabolic diseases. The lymphatic clearance of different tissues from waste products, viruses, bacteria and toxic proteins significantly contributes to the correspondent recovery processes. However, understanding of the meningeal lymphatics functions is a challenging problem. The exploration of mechanisms of lymphatic communication with brain fluids as well as the role of the lymphatic system in the brain drainage, clearance and recovery are still in its infancy. Here we review novel concepts on the anatomy and physiology of the lymphatics in the brain, which warrant a substantial revision of our knowledge about the role of lymphatics in the rehabilitation of the brain functions after neural pathologies. We discuss a new vision on how to recruit the meningeal lymphatics by the opening of blood-brain barrier as a trigger mechanism of activation of the meningeal lymphatic drainage. This leads to innovative strategies in neurorehabilitation therapy.

2018 ◽  
Vol 19 (12) ◽  
pp. 3818 ◽  
Author(s):  
Oxana Semyachkina-Glushkovskaya ◽  
Dmitry Postnov ◽  
Jürgen Kurths

The peripheral lymphatic system plays a crucial role in the recovery mechanisms after many pathological changes, such as infection, trauma, vascular, or metabolic diseases. The lymphatic clearance of different tissues from waste products, viruses, bacteria, and toxic proteins significantly contributes to the correspondent recovery processes. However, understanding of the cerebral lymphatic functions is a challenging problem. The exploration of mechanisms of lymphatic communication with brain fluids as well as the role of the lymphatic system in brain drainage, clearance, and recovery is still in its infancy. Here we review novel concepts on the anatomy and physiology of the lymphatics in the brain, which warrant a substantial revision of our knowledge about the role of lymphatics in the rehabilitation of the brain functions after neural pathologies. We discuss a new vision on the connective bridge between the opening of a blood–brain barrier and activation of the meningeal lymphatic clearance. The ability to stimulate the lymph flow in the brain, is likely to play an important role in developing future innovative strategies in neurorehabilitation therapy.


2021 ◽  
Vol 15 ◽  
Author(s):  
Sichao Chen ◽  
Linqian Shao ◽  
Li Ma

Brain edema is a severe stroke complication that is associated with prolonged hospitalization and poor outcomes. Swollen tissues in the brain compromise cerebral perfusion and may also result in transtentorial herniation. As a physical and biochemical barrier between the peripheral circulation and the central nervous system (CNS), the blood–brain barrier (BBB) plays a vital role in maintaining the stable microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the dysfunction of the BBB results in increased paracellular permeability, directly contributing to the extravasation of blood components into the brain and causing cerebral vasogenic edema. Recent studies have led to the discovery of the glymphatic system and meningeal lymphatic vessels, which provide a channel for cerebrospinal fluid (CSF) to enter the brain and drain to nearby lymph nodes and communicate with the peripheral immune system, modulating immune surveillance and brain responses. A deeper understanding of the function of the cerebral lymphatic system calls into question the known mechanisms of cerebral edema after stroke. In this review, we first discuss how BBB disruption after stroke can cause or contribute to cerebral edema from the perspective of molecular and cellular pathophysiology. Finally, we discuss how the cerebral lymphatic system participates in the formation of cerebral edema after stroke and summarize the pathophysiological process of cerebral edema formation after stroke from the two directions of the BBB and cerebral lymphatic system.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 399 ◽  
Author(s):  
Catarina Chaves ◽  
Xavier Declèves ◽  
Meryam Taghi ◽  
Marie-Claude Menet ◽  
Joelle Lacombe ◽  
...  

The blood–brain barrier (BBB) hinders the brain delivery of many anticancer drugs. In pediatric patients, diffuse intrinsic pontine glioma (DIPG) represents the main cause of brain cancer mortality lacking effective drug therapy. Using sham and DIPG-bearing rats, we analyzed (1) the brain distribution of 3-kDa-Texas red-dextran (TRD) or [14C]-sucrose as measures of BBB integrity, and (2) the role of major ATP-binding cassette (ABC) transporters at the BBB on the efflux of the irinotecan metabolite [3H]-SN-38. The unaffected [14C]-sucrose or TRD distribution in the cerebrum, cerebellum, and brainstem regions in DIPG-bearing animals suggests an intact BBB. Targeted proteomics retrieved no change in P-glycoprotein (P-gp), BCRP, MRP1, and MRP4 levels in the analyzed regions of DIPG rats. In vitro, DIPG cells express BCRP but not P-gp, MRP1, or MRP4. Dual inhibition of P-gp/Bcrp, or Mrp showed a significant increase on SN-38 BBB transport: Cerebrum (8.3-fold and 3-fold, respectively), cerebellum (4.2-fold and 2.8-fold), and brainstem (2.6-fold and 2.2-fold). Elacridar increased [3H]-SN-38 brain delivery beyond a P-gp/Bcrp inhibitor effect alone, emphasizing the role of another unidentified transporter in BBB efflux of SN-38. These results confirm a well-preserved BBB in DIPG-bearing rats, along with functional ABC-transporter expression. The development of chemotherapeutic strategies to circumvent ABC-mediated BBB efflux are needed to improve anticancer drug delivery against DIPG.


2019 ◽  
Vol 20 (7) ◽  
pp. 1632 ◽  
Author(s):  
Michelle Erickson ◽  
William Banks

Age is associated with altered immune functions that may affect the brain. Brain barriers, including the blood–brain barrier (BBB) and blood–CSF barrier (BCSFB), are important interfaces for neuroimmune communication, and are affected by aging. In this review, we explore novel mechanisms by which the aging immune system alters central nervous system functions and neuroimmune responses, with a focus on brain barriers. Specific emphasis will be on recent works that have identified novel mechanisms by which BBB/BCSFB functions change with age, interactions of the BBB with age-associated immune factors, and contributions of the BBB to age-associated neurological disorders. Understanding how age alters BBB functions and responses to pathological insults could provide important insight on the role of the BBB in the progression of cognitive decline and neurodegenerative disease.


Physiology ◽  
2002 ◽  
Vol 17 (6) ◽  
pp. 231-234 ◽  
Author(s):  
Bruno Hagenbuch ◽  
Bo Gao ◽  
Peter. J. Meier

Distinct transport proteins regulate the movement of waste products and xenobiotics across the blood-brain barrier (BBB). Members of the drug transporter families MDR, MRP, and OATP have been identified in the BBB, and a detailed characterization of the involved proteins is now required to target drugs more efficiently to the brain.


2020 ◽  
Vol 18 (12) ◽  
pp. 1237-1249 ◽  
Author(s):  
Ruiqing Kang ◽  
Marcin Gamdzyk ◽  
Cameron Lenahan ◽  
Jiping Tang ◽  
Sheng Tan ◽  
...  

It is well-known that stroke is one of the leading causes of death and disability all over the world. After a stroke, the blood-brain barrier subsequently breaks down. The BBB consists of endothelial cells surrounded by astrocytes. Microglia, considered the long-living resident immune cells of the brain, play a vital role in BBB function. M1 microglia worsen BBB disruption, while M2 microglia assist in repairing BBB damage. Microglia can also directly interact with endothelial cells and affect BBB permeability. In this review, we are going to discuss the mechanisms responsible for the dual role of microglia in BBB dysfunction after stroke.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yvonne Cashinn Chia ◽  
Clarice Evey Anjum ◽  
Hui Rong Yee ◽  
Yenny Kenisi ◽  
Mike K. S. Chan ◽  
...  

Blood-brain barrier (BBB) is a term describing the highly selective barrier formed by the endothelial cells (ECs) of the central nervous system (CNS) homeostasis by restricting movement across the BBB. An intact BBB is critical for normal brain functions as it maintains brain homeostasis, modulates immune cell transport, and provides protection against pathogens and other foreign substances. However, it also prevents drugs from entering the CNS to treat neurodegenerative diseases. Stem cells, on the other hand, have been reported to bypass the BBB and successfully home to their target in the brain and initiate repair, making them a promising approach in cellular therapy, especially those related to neurodegenerative disease. This review article discusses the mechanism behind the successful homing of stem cells to the brain, their potential role as a drug delivery vehicle, and their applications in neurodegenerative diseases.


2006 ◽  
Vol 74 (12) ◽  
pp. 6982-6991 ◽  
Author(s):  
Peter Bergman ◽  
Linda Johansson ◽  
Hong Wan ◽  
Allison Jones ◽  
Richard L. Gallo ◽  
...  

ABSTRACT Antimicrobial peptides are present in most living species and constitute important effector molecules of innate immunity. Recently, we and others have detected antimicrobial peptides in the brain. This is an organ that is rarely infected, which has mainly been ascribed to the protective functions of the blood-brain barrier (BBB) and meninges. Since the bactericidal properties of the BBB and meninges are not known, we hypothesized that antimicrobial peptides could play a role in these barriers. We addressed this hypothesis by infecting mice with the neuropathogenic bacterium Neisseria meningitidis. Brains were analyzed for expression of the antimicrobial peptide CRAMP by immunohistochemistry in combination with confocal microscopy. After infection, we observed induction of CRAMP in endothelial cells of the BBB and in cells of the meninges. To explore the functional role of CRAMP in meningococcal disease, we infected mice deficient of the CRAMP gene. Even though CRAMP did not appear to protect the brain from invasion of meningococci, CRAMP knockout mice were more susceptible to meningococcal infection than wild-type mice and exhibited increased meningococcal growth in blood, liver, and spleen. Moreover, we could demonstrate that carbonate, a compound that accumulates in the circulation during metabolic acidosis, makes meningococci more susceptible to CRAMP.


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