scholarly journals Signs of Myelin Impairment in Cerebrospinal Fluid After Osmotic Opening of the Blood-Brain Barrier in Rats

2015 ◽  
pp. S603-S608 ◽  
Author(s):  
P. KOZLER ◽  
O. SOBEK ◽  
J. POKORNÝ

A number of clinical neurological pathologies are associated with increased permeability of the blood brain barrier (BBB). Induced changes of the homeostatic mechanisms in the brain microenvironment lead among others to cellular changes in the CNS. The question was whether some of these changes can be induced by osmotic opening of BBB in an in vivo experiment and whether they can be detected in cerebrospinal fluid (CSF). CSF was taken via the suboccipital puncture from 10 healthy rats and six rats after the osmotic opening of the BBB. In all 16 animals, concentration of myelin basic protein (MBP ng/ml), Neuron-specific enolase (NSE ng/ml) and Tau-protein (Tau pg/ml) were determined in CSF by ELISA. Values in both groups were statistically evaluated. Significant difference between the control and experimental group was revealed only for the concentration of myelin basic protein (p<0.01). The presented results indicate that osmotic opening of the BBB in vivo experiment without the presence of other pathological conditions of the brain leads to a damage of myelin, without impairment of neurons or their axons.

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1833
Author(s):  
Shannon Morgan McCabe ◽  
Ningning Zhao

Manganese (Mn) is a trace nutrient necessary for life but becomes neurotoxic at high concentrations in the brain. The brain is a “privileged” organ that is separated from systemic blood circulation mainly by two barriers. Endothelial cells within the brain form tight junctions and act as the blood–brain barrier (BBB), which physically separates circulating blood from the brain parenchyma. Between the blood and the cerebrospinal fluid (CSF) is the choroid plexus (CP), which is a tissue that acts as the blood–CSF barrier (BCB). Pharmaceuticals, proteins, and metals in the systemic circulation are unable to reach the brain and spinal cord unless transported through either of the two brain barriers. The BBB and the BCB consist of tightly connected cells that fulfill the critical role of neuroprotection and control the exchange of materials between the brain environment and blood circulation. Many recent publications provide insights into Mn transport in vivo or in cell models. In this review, we will focus on the current research regarding Mn metabolism in the brain and discuss the potential roles of the BBB and BCB in maintaining brain Mn homeostasis.


2020 ◽  
Vol 13 (10) ◽  
pp. 279
Author(s):  
Dina Sikpa ◽  
Lisa Whittingstall ◽  
Martin Savard ◽  
Réjean Lebel ◽  
Jérôme Côté ◽  
...  

The blood–brain barrier (BBB) is a major obstacle to the development of effective diagnostics and therapeutics for brain cancers and other central nervous system diseases. Peptide agonist analogs of kinin B1 and B2 receptors, acting as BBB permeabilizers, have been utilized to overcome this barrier. The purpose of the study was to provide new insights for the potential utility of kinin analogs as brain drug delivery adjuvants. In vivo imaging studies were conducted in various animal models (primary/secondary brain cancers, late radiation-induced brain injury) to quantify BBB permeability in response to kinin agonist administrations. Results showed that kinin B1 (B1R) and B2 receptors (B2R) agonists increase the BBB penetration of chemotherapeutic doxorubicin to glioma sites, with additive effects when applied in combination. B2R agonist also enabled extravasation of high-molecular-weight fluorescent dextrans (155 kDa and 2 MDa) in brains of normal mice. Moreover, a systemic single dose of B2R agonist did not increase the incidence of metastatic brain tumors originating from circulating breast cancer cells. Lastly, B2R agonist promoted the selective delivery of co-injected diagnostic MRI agent Magnevist in irradiated brain areas, depicting increased vascular B2R expression. Altogether, our findings suggest additional evidence for using kinin analogs to facilitate specific access of drugs to the brain.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi82-vi82 ◽  
Author(s):  
Ellina Schulz ◽  
Almuth F Kessler ◽  
Ellaine Salvador ◽  
Dominik Domröse ◽  
Malgorzata Burek ◽  
...  

Abstract OBJECTIVE For glioblastoma patients Tumor Treating Fields (TTFields) have been established as adjuvant therapy. The blood brain barrier (BBB) tightly controls the influx of the majority of compounds from blood to brain. Therefore, the BBB may block delivery of drugs for treatment of brain tumors. Here, the influence of TTFields on BBB permeability was assessed in vivo. METHODS Rats were treated with 100 kHz TTFields for 72 h and thereupon i.v. injected with Evan’s Blue (EB) which directly binds to Albumin. To evaluate effects on BBB, EB was extracted after brain homogenization and quantified. In addition, cryosections of rat brains were prepared following TTFields application. The sections were stained for tight junction proteins Claudin-5 and Occludin and for immunoglobulin G (IgG) to assess vessel structure. Furthermore, serial dynamic contrast-enhanced DCE-MRI with Gadolinium contrast agent was performed before and after TTFields application. RESULTS TTFields application significantly increased the EB accumulation in the rat brain. In TTFields-treated rats, the vessel structure became diffuse compared to control cryosections of rat brains; Claudin 5 and Occludin were delocalized and IgG was found throughout the brain tissue. Serial DCE-MRI demonstrated significantly increased accumulation of Gadolinium in the brain, observed directly after 72 h of TTFields application. The effect of TTFields on the BBB disappeared 96 h after end of treatment and no difference in contrast enhancement between controls and TTFields treated animals was detectable. CONCLUSION By altering BBB integrity and permeability, application of TTFields at 100 kHz may have the potential to deliver drugs to the brain, which are unable to cross the BBB. Utilizing TTFields to open the BBB and its subsequent recovery could be a clinical approach of drug delivery for treatment of brain tumors and other diseases of the central nervous system. These results will be further validated in clinical Trials.


2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Vidmantas Petraitis ◽  
Ruta Petraitiene ◽  
Jessica M. Valdez ◽  
Vasilios Pyrgos ◽  
Martin J. Lizak ◽  
...  

ABSTRACT Hematogenous Candida meningoencephalitis (HCME) is a life-threatening complication of neonates and immunocompromised children. Amphotericin B (AmB) shows poor permeation and low cerebrospinal fluid (CSF) concentrations but is effective in the treatment of HCME. In order to better understand the mechanism of CNS penetration of AmB, we hypothesized that AmB may achieve focally higher concentrations in infected CNS lesions. An in vitro blood-brain barrier (BBB) model was serially infected with Candida albicans. Liposomal AmB (LAMB) or deoxycholate AmB (DAMB) at 5 μg/ml was then provided, and the vascular and CNS compartments were sampled 4 h later. For in vivo correlation, rabbits with experimental HCME received a single dose of DAMB at 1 mg/kg of body weight or LAMB at 5 mg/kg and were euthanized after 1, 3, 6, and 24 h. Evans blue dye solution (2%, 2 ml/kg) administered intravenously (i.v.) at 1 h prior to euthanasia stained infected regions of tissue but not histologically normal areas. AmB concentrations in stained and unstained tissue regions were measured using ultraperformance liquid chromatography. For selected rabbits, magnetic resonance imaging (MRI) scans performed on days 1 to 7 postinoculation were acquired before and after i.v. bolus administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) at 15-min intervals through 2 h postinjection. The greatest degree of penetration of DAMB and LAMB through the in vitro BBB occurred after 24 h of exposure (P = 0.0022). In vivo the concentrations of LAMB and DAMB in brain abscesses were 4.35 ± 0.59 and 3.14 ± 0.89 times higher, respectively, than those in normal tissue (P ≤ 0.019). MRI scans demonstrated that Gd-DTPA accumulated in infected areas with a disrupted BBB. Localized BBB disruption in HCME allows high concentrations of AmB within infected tissues, despite the presence of low cerebrospinal fluid concentrations.


2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Inge C. M. Verheggen ◽  
Joost J. A. de Jong ◽  
Martin P. J. van Boxtel ◽  
Alida A. Postma ◽  
Frans R. J. Verhey ◽  
...  

Abstract Background Circumventricular organs (CVOs) are small structures without a blood–brain barrier surrounding the brain ventricles that serve homeostasic functions and facilitate communication between the blood, cerebrospinal fluid and brain. Secretory CVOs release peptides and sensory CVOs regulate signal transmission. However, pathogens may enter the brain through the CVOs and trigger neuroinflammation and neurodegeneration. We investigated the feasibility of dynamic contrast-enhanced (DCE) MRI to assess the CVO permeability characteristics in vivo, and expected significant contrast uptake in these regions, due to blood–brain barrier absence. Methods Twenty healthy, middle-aged to older males underwent brain DCE MRI. Pharmacokinetic modeling was applied to contrast concentration time-courses of CVOs, and in reference to white and gray matter. We investigated whether a significant and positive transfer from blood to brain could be measured in the CVOs, and whether this differed between secretory and sensory CVOs or from normal-appearing brain matter. Results In both the secretory and sensory CVOs, the transfer constants were significantly positive, and all secretory CVOs had significantly higher transfer than each sensory CVO. The transfer constants in both the secretory and sensory CVOs were higher than in the white and gray matter. Conclusions Current measurements confirm the often-held assumption of highly permeable CVOs, of which the secretory types have the strongest blood-to-brain transfer. The current study suggests that DCE MRI could be a promising technique to further assess the function of the CVOs and how pathogens can potentially enter the brain via these structures. Trial registration: Netherlands Trial Register number: NL6358, date of registration: 2017-03-24


1981 ◽  
Vol 15 (5) ◽  
pp. 341-368 ◽  
Author(s):  
Mark L. Richards ◽  
Randall A. Prince ◽  
Karen A. Kenaley ◽  
Jeanine A. Johnson ◽  
Jack L. LeFrock

The complex physiology of the blood-brain barrier and the characteristics of an antimicrobial which govern its distribution into the brain are poorly understood. Likewise, available data regarding CSF antimicrobial concentrations after extra-CNS administration, as tabulated in this review, are inadequate. Because of the potentially dire consequences that result from inappropriately treated CNS infections, large cooperative studies using standardized methodology are needed. Suggestions for such methods are outlined.


2007 ◽  
Vol 35 (9) ◽  
pp. 1459-1462 ◽  
Author(s):  
Amal Kaddoumi ◽  
Sung-Up Choi ◽  
Loren Kinman ◽  
Dale Whittington ◽  
Che-Chung Tsai ◽  
...  

2016 ◽  
Vol 37 (6) ◽  
pp. 2185-2195 ◽  
Author(s):  
Sylvain Auvity ◽  
Hélène Chapy ◽  
Sébastien Goutal ◽  
Fabien Caillé ◽  
Benoit Hosten ◽  
...  

Diphenhydramine, a sedative histamine H1-receptor (H1R) antagonist, was evaluated as a probe to measure drug/H+-antiporter function at the blood–brain barrier. In situ brain perfusion experiments in mice and rats showed that diphenhydramine transport at the blood–brain barrier was saturable, following Michaelis–Menten kinetics with a Km = 2.99 mM and Vmax = 179.5 nmol s−1 g−1. In the pharmacological plasma concentration range the carrier-mediated component accounted for 77% of diphenhydramine influx while passive diffusion accounted for only 23%. [14C]Diphenhydramine blood–brain barrier transport was proton and clonidine sensitive but was influenced by neither tetraethylammonium, a MATE1 (SLC47A1), and OCT/OCTN (SLC22A1-5) modulator, nor P-gp/Bcrp (ABCB1a/1b/ABCG2) deficiency. Brain and plasma kinetics of [11C]diphenhydramine were measured by positron emission tomography imaging in rats. [11C]Diphenhydramine kinetics in different brain regions were not influenced by displacement with 1 mg kg−1 unlabeled diphenhydramine, indicating the specificity of the brain positron emission tomography signal for blood–brain barrier transport activity over binding to any central nervous system target in vivo. [11C]Diphenhydramine radiometabolites were not detected in the brain 15 min after injection, allowing for the reliable calculation of [11C]diphenhydramine brain uptake clearance (Clup = 0.99 ± 0.18 mL min−1 cm−3). Diphenhydramine is a selective and specific H+-antiporter substrate. [11C]Diphenhydramine positron emission tomography imaging offers a reliable and noninvasive method to evaluate H+-antiporter function at the blood–brain barrier.


2008 ◽  
Vol 82 (15) ◽  
pp. 7591-7600 ◽  
Author(s):  
Hongwei Wang ◽  
Jinglin Sun ◽  
Harris Goldstein

ABSTRACT Human immunodeficiency virus type 1 (HIV-1), introduced into the brain by HIV-1-infected monocytes which migrate across the blood-brain barrier (BBB), infects resident macrophages and microglia and initiates a process that causes HIV-1-associated neurocognitive disorders. The mechanism by which HIV-1 infection circumvents the BBB-restricted passage of systemic leukocytes into the brain and disrupts the integrity of the BBB is not known. Circulating lipopolysaccharide (LPS), which can compromise the integrity of the BBB, is significantly increased in HIV-1-infected individuals. We hypothesized that HIV-1 infection increases monocyte capacity to migrate across the BBB, which is further facilitated by a compromise of BBB integrity mediated by the increased systemic LPS levels present in HIV-1-infected individuals. To investigate this possibility, we examined the in vivo BBB migration of monocytes derived from our novel mouse model, JR-CSF/EYFP mice, which are transgenic for both a long terminal repeat-regulated full-length infectious HIV-1 provirus and ROSA-26-regulated enhanced yellow fluorescent protein. We demonstrated that JR-CSF/EYFP mouse monocytes displayed an increased capacity to enter the brain by crossing either an intact BBB or a BBB whose integrity was partially compromised by systemic LPS. We also demonstrated that the JR-CSF mouse BBB was more susceptible to disruption by systemic LPS than the control wild-type mouse BBB. These results demonstrated that HIV-1 infection increased the ability of monocytes to enter the brain and increased the sensitivity of the BBB to disruption by systemic LPS, which is elevated in HIV-1-infected individuals. These mice represent a new in vivo system for studying the mechanism by which HIV-1-infected monocytes migrate into the brain.


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