scholarly journals Vector-Mediated Transport Producing Drug-like Peptides

2018 ◽  
Author(s):  
Kenneth A Gruber ◽  
James A Cowan ◽  
Ada Cowan ◽  
Wenbin Qi ◽  
Stephan Pearson ◽  
...  

Drugs that are structural mimetics of peptides (e.g. small molecules) have been plagued by problems associated with oral availability and transcellular movement. Vector-mediated transport, where a potentially therapeutic drug is covalently linked to another molecule that is a ligand for an active transport or transcytosis system, was developed as an approach for moving a drug across the blood-brain-barrier. We now report a vector approach that produced peptides with oral activity, blood-brain-barrier transport, and extended in vivo half-life. Generating these properties requires secondary structure stabilization into a β hairpin, and the addition of a C-terminal dipeptide sequence composed of non-polar residues. Peptides with biological activity incompatible with these derivatizations were covalently linked to a model transport vector, producing a chimera with the therapeutic activity of the peptide and the transport properties of the vector. Our platform technology may be a general approach for the design of drug-like peptides.


2020 ◽  
Vol 21 (9) ◽  
pp. 674-684 ◽  
Author(s):  
Saleha Rehman ◽  
Bushra Nabi ◽  
Faheem Hyder Pottoo ◽  
Sanjula Baboota ◽  
Javed Ali

Background: Neuropsychiatric diseases primarily characterized by dementia stand third in the global list of diseases causing disability. The poor water solubility, erratic oral absorption, low bioavailability, poor intestinal absorption, and the impeding action of the blood-brain barrier (BBB) are the major factors limiting the therapeutic feasibility of the antipsychotics. Only a small percentage of antipsychotics reaches the therapeutic target site, which warrants administration of high doses, consequently leading to unwanted side-effects. Hence the main struggle for the effective treatment of neuropsychiatric diseases occurs “at the gates” of the brain, which can be mitigated with the use of a nanotechnology-based platform. Methods: The goal of this review is to undertake a comprehensive study about the role of lipid nanoformulations in facilitating the delivery of antipsychotics across BBB along with the available in vitro and in vivo evidence. Results: Lipid nanoformulations have attained great popularity for the delivery of therapeutics into the brain. Their nanosize helps in overcoming the biological barriers, thereby providing easy BBB translocation of the drugs. Besides, they offer numerous advantages like controlled and targeted drug release, minimizing drug efflux, long storage stability, augmented bioavailability, and reduced adverse drug effects to attain an optimal therapeutic drug concentration in the brain. Moreover, employing alternative routes of administration has also shown promising results. Conclusion: Thus, it can be concluded that the lipid nanoformulations bear immense potential in overcoming the challenges associated with the treatment of neuropsychiatric disorders. However, the area warrants further clinical studies to ensure their commercialization, which could revolutionize the treatment of neuropsychiatric diseases in the coming decades.



1996 ◽  
Vol 22 (2) ◽  
pp. 118-128 ◽  
Author(s):  
S. Isenmann ◽  
S. Brandner ◽  
G. Kuhne ◽  
J. Boner ◽  
A. Aguzzi


1996 ◽  
Vol 84 (3) ◽  
pp. 494-502 ◽  
Author(s):  
Bernhard Zünkeler ◽  
Richard E. Carson ◽  
Jeffrey Olson ◽  
Ronald G. Blasberg ◽  
Mary Girton ◽  
...  

✓ Hyperosmolar blood-brain barrier (BBB) disruption remains controversial as an adjuvant therapy to increase delivery of water-soluble compounds to extracellular space in the brain in patients with malignant brain tumors. To understand the physiological effects of BBB disruption more clearly, the authors used positron emission tomography (PET) to study the time course of BBB permeability in response to the potassium analog rubidium-82 (82Rb, halflife 75 seconds) following BBB disruption in anesthetized adult baboons. Mannitol (25%) was injected into the carotid artery and PET scans were performed before and serially at 8- to 15-minute intervals after BBB disruption. The mean influx constant (K1), a measure of permeability-surface area product, in ipsilateral, mannitol-perfused mixed gray- and white-matter brain regions was 4.9 ± 2.4 µl/min/ml (± standard deviation) at baseline and increased more than 100% (ΔK1 = 9.4 ± 5.1 µl/min/ml, 18 baboons) in brain perfused by mannitol. The effect of BBB disruption on K1 correlated directly with the total amount of mannitol administered (p < 0.005). Vascular permeability returned to baseline with a halftime of 24.0 ± 14.3 minutes. The mean brain plasma volume rose by 0.57 ± 0.34 ml/100 ml in ipsilateral perfused brain following BBB disruption. This work provides a basis for the in vivo study of permeability changes induced by BBB disruption in human brain and brain tumors.



2018 ◽  
Vol 283 ◽  
pp. 126-134 ◽  
Author(s):  
Satoshi Zeniya ◽  
Hiroya Kuwahara ◽  
Kaiichi Daizo ◽  
Akihiro Watari ◽  
Masuo Kondoh ◽  
...  


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.





2005 ◽  
Vol 289 (5) ◽  
pp. H2012-H2019 ◽  
Author(s):  
Melissa A. Fleegal ◽  
Sharon Hom ◽  
Lindsay K. Borg ◽  
Thomas P. Davis

The blood-brain barrier (BBB) is a metabolic and physiological barrier important for maintaining brain homeostasis. The aim of this study was to determine the role of PKC activation in BBB paracellular permeability changes induced by hypoxia and posthypoxic reoxygenation using in vitro and in vivo BBB models. In rat brain microvessel endothelial cells (RMECs) exposed to hypoxia (1% O2-99% N2; 24 h), a significant increase in total PKC activity was observed, and this was reduced by posthypoxic reoxygenation (95% room air-5% CO2) for 2 h. The expression of PKC-βII, PKC-γ, PKC-η, PKC-μ, and PKC-λ also increased following hypoxia (1% O2-99% N2; 24 h), and these protein levels remained elevated following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Increases in the expression of PKC-ε and PKC-ζ were also observed following posthypoxic reoxygenation (95% room air-5% CO2; 2 h). Moreover, inhibition of PKC with chelerythrine chloride (10 μM) attenuated the hypoxia-induced increases in [14C]sucrose permeability. Similar to what was observed in RMECs, total PKC activity was also stimulated in cerebral microvessels isolated from rats exposed to hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min). In contrast, hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min) significantly increased the expression levels of only PKC-γ and PKC-θ in the in vivo hypoxia model. These data demonstrate that hypoxia-induced BBB paracellular permeability changes occur via a PKC-dependent mechanism, possibly by differentially regulating the protein expression of the 11 PKC isozymes.



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