scholarly journals Modulation of the blood-tumor barrier to enhance drug delivery and efficacy for brain metastases

2021 ◽  
Vol 3 (Supplement_5) ◽  
pp. v133-v143
Author(s):  
Kathryn E Blethen ◽  
Tasneem A Arsiwala ◽  
Ross A Fladeland ◽  
Samuel A Sprowls ◽  
Dhruvi M Panchal ◽  
...  

Abstract The blood-brain barrier is the selectively permeable vasculature of the brain vital for maintaining homeostasis and neurological function. Low permeability is beneficial in the presence of toxins and pathogens in the blood. However, in the presence of metastatic brain tumors, it is a challenge for drug delivery. Although the blood-tumor barrier is slightly leaky, it still is not permissive enough to allow the accumulation of therapeutic drug concentrations in brain metastases. Herein, we discuss the differences between primary brain tumors and metastatic brain tumors vasculature, effects of therapeutics on the blood-tumor barrier, and characteristics to be manipulated for more effective drug delivery.

2012 ◽  
Vol 32 (1) ◽  
pp. E4 ◽  
Author(s):  
Hao-Li Liu ◽  
Hung-Wei Yang ◽  
Mu-Yi Hua ◽  
Kuo-Chen Wei

Malignant glioma is a severe primary CNS cancer with a high recurrence and mortality rate. The current strategy of surgical debulking combined with radiation therapy or chemotherapy does not provide good prognosis, tumor progression control, or improved patient survival. The blood-brain barrier (BBB) acts as a major obstacle to chemotherapeutic treatment of brain tumors by severely restricting drug delivery into the brain. Because of their high toxicity, chemotherapeutic drugs cannot be administered at sufficient concentrations by conventional delivery methods to significantly improve long-term survival of patients with brain tumors. Temporal disruption of the BBB by microbubble-enhanced focused ultrasound (FUS) exposure can increase CNS-blood permeability, providing a promising new direction to increase the concentration of therapeutic agents in the brain tumor and improve disease control. Under the guidance and monitoring of MR imaging, a brain drug-delivery platform can be developed to control and monitor therapeutic agent distribution and kinetics. The success of FUS BBB disruption in delivering a variety of therapeutic molecules into brain tumors has recently been demonstrated in an animal model. In this paper the authors review a number of critical studies that have demonstrated successful outcomes, including enhancement of the delivery of traditional clinically used chemotherapeutic agents or application of novel nanocarrier designs for actively transporting drugs or extending drug half-lives to significantly improve treatment efficacy in preclinical animal models.


2019 ◽  
Vol 87 (1) ◽  
pp. 6 ◽  
Author(s):  
Luca Bors ◽  
Franciska Erdő

Treatment of certain central nervous system disorders, including different types of cerebral malignancies, is limited by traditional oral or systemic administrations of therapeutic drugs due to possible serious side effects and/or lack of the brain penetration and, therefore, the efficacy of the drugs is diminished. During the last decade, several new technologies were developed to overcome barrier properties of cerebral capillaries. This review gives a short overview of the structural elements and anatomical features of the blood–brain barrier. The various in vitro (static and dynamic), in vivo (microdialysis), and in situ (brain perfusion) blood–brain barrier models are also presented. The drug formulations and administration options to deliver molecules effectively to the central nervous system (CNS) are presented. Nanocarriers, nanoparticles (lipid, polymeric, magnetic, gold, and carbon based nanoparticles, dendrimers, etc.), viral and peptid vectors and shuttles, sonoporation and microbubbles are briefly shown. The modulation of receptors and efflux transporters in the cell membrane can also be an effective approach to enhance brain exposure to therapeutic compounds. Intranasal administration is a noninvasive delivery route to bypass the blood–brain barrier, while direct brain administration is an invasive mode to target the brain region with therapeutic drug concentrations locally. Nowadays, both technological and mechanistic tools are available to assist in overcoming the blood–brain barrier. With these techniques more effective and even safer drugs can be developed for the treatment of devastating brain disorders.


2020 ◽  
Vol 26 (19) ◽  
pp. 2247-2256 ◽  
Author(s):  
Surbhi Sharma ◽  
Shweta Dang

Neuropsychological disorders are now growing rapidly worldwide among the people of diverse backgrounds irrespective of age, gender, and geographical region. Such disorders not only disturb the normal life and functionality of an individual but also impact the social relationships of the patient and the people associated with them, and if not treated in time, it may also result in mortality in severe conditions. Various antipsychotic drugs have been developed but their use is often limited by issues related to effective drug delivery at the site of action i.e. brain, mainly because of the blood-brain barrier. To resolve these issues, researchers and scientists have been working to develop a more effective drug delivery system where drugs can cross the blood-brain barrier and reach the brain in more effective concentrations. Drugs have been modified and formulated into nano-carriers and experimental studies for efficient and targeted delivery of drugs have been conducted. This review focuses on certain common neuropsychological diseases and their nanocarriers developed for drug delivery in the brain and are discussed with a brief description of various experimental in vitro and in vivo studies. This review also focuses on the intranasal route for the delivery of antipsychotic drugs and constraints faced due to the blood-brain barrier by the drugs.


2020 ◽  
Vol 26 (37) ◽  
pp. 4721-4737 ◽  
Author(s):  
Bhumika Kumar ◽  
Mukesh Pandey ◽  
Faheem H. Pottoo ◽  
Faizana Fayaz ◽  
Anjali Sharma ◽  
...  

Parkinson’s disease is one of the most severe progressive neurodegenerative disorders, having a mortifying effect on the health of millions of people around the globe. The neural cells producing dopamine in the substantia nigra of the brain die out. This leads to symptoms like hypokinesia, rigidity, bradykinesia, and rest tremor. Parkinsonism cannot be cured, but the symptoms can be reduced with the intervention of medicinal drugs, surgical treatments, and physical therapies. Delivering drugs to the brain for treating Parkinson’s disease is very challenging. The blood-brain barrier acts as a highly selective semi-permeable barrier, which refrains the drug from reaching the brain. Conventional drug delivery systems used for Parkinson’s disease do not readily cross the blood barrier and further lead to several side-effects. Recent advancements in drug delivery technologies have facilitated drug delivery to the brain without flooding the bloodstream and by directly targeting the neurons. In the era of Nanotherapeutics, liposomes are an efficient drug delivery option for brain targeting. Liposomes facilitate the passage of drugs across the blood-brain barrier, enhances the efficacy of the drugs, and minimize the side effects related to it. The review aims at providing a broad updated view of the liposomes, which can be used for targeting Parkinson’s disease.


2020 ◽  
Vol 26 (13) ◽  
pp. 1448-1465 ◽  
Author(s):  
Jozef Hanes ◽  
Eva Dobakova ◽  
Petra Majerova

Tauopathies are neurodegenerative disorders characterized by the deposition of abnormal tau protein in the brain. The application of potentially effective therapeutics for their successful treatment is hampered by the presence of a naturally occurring brain protection layer called the blood-brain barrier (BBB). BBB represents one of the biggest challenges in the development of therapeutics for central nervous system (CNS) disorders, where sufficient BBB penetration is inevitable. BBB is a heavily restricting barrier regulating the movement of molecules, ions, and cells between the blood and the CNS to secure proper neuronal function and protect the CNS from dangerous substances and processes. Yet, these natural functions possessed by BBB represent a great hurdle for brain drug delivery. This review is concentrated on summarizing the available methods and approaches for effective therapeutics’ delivery through the BBB to treat neurodegenerative disorders with a focus on tauopathies. It describes the traditional approaches but also new nanotechnology strategies emerging with advanced medical techniques. Their limitations and benefits are discussed.


2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii28-ii28
Author(s):  
S Weil ◽  
E Jung ◽  
D Domínguez Azorín ◽  
J Higgins ◽  
J Reckless ◽  
...  

Abstract BACKGROUND Glioblastomas are notoriously therapy resistant tumors. As opposed to other tumor entities, no major advances in therapeutic success have been made in the past decades. This has been calling for a deeper biological understanding of the tumor, its growth and resistance patterns. We have been using a xenograft glioma model, where human glioblastoma cells are implanted under chronic cranial windows and studied longitudinally over many weeks and months using multi photon laser scanning microscopy (MPLSM). To test the effect of (new) drugs, a stable and direct delivery system avoiding the blood-brain-barrier has come into our interest. MATERIAL AND METHODS We implanted cranial windows and fluorescently labeled human glioblastoma stem-like cells into NMRI nude mice to follow up on the tumor development in our MPLSM model. After tumor establishment, an Alzet® micropump was implanted to directly deliver agents via a catheter system continuously over 28 days directly under the cranial window onto the brain surface. Using the MPLSM technique, the continuous delivery and infusion of drugs onto the brain and into the tumor was measured over many weeks in detail using MPLSM. RESULTS The establishment of the combined methods allowed reliable concurrent drug delivery over 28 days bypassing the blood-brain-barrier. Individual regions and tumor cells could be measured and followed up before, and after the beginning of the treatment, as well as after the end of the pump activity. Fluorescently labelled drugs were detectable in the MPLSM and its distribution into the brain parenchyma could be quantified. After the end of the micropump activity, further MPLSM measurements offer the possibility to observe long term effects of the applied drug on the tumor. CONCLUSION The combination of tumor observation in the MPSLM and concurrent continuous drug delivery is a feasible and reliable method for the investigation of (novel) anti-tumor agents, especially drugs that are not blood-brain-barrier penetrant. Morphological or even functional changes of individual tumor cells can be measured under and after treatment. These techniques can be used to test new drugs targeting the tumor, its tumor microtubes and tumor cells networks, and measure the effects longitudinally.


2021 ◽  
Vol 27 ◽  
Author(s):  
Dhara Lakdawala ◽  
Md Abdur Rashid ◽  
Farhan Jalees Ahmad

: Drug delivery to the brain has remained a significant challenge in treating neurodegenerative disorders such as Alzheimer's disease due to the presence of the blood-brain barrier, which primarily obstructs the access of drugs and biomolecules into the brain. Several methods to overcome the blood-brain barrier have been employed, such as chemical disruption, surgical intervention, focused ultrasound, intranasal delivery and using nanocarriers. Nanocarrier systems remain the method of choice and have shown promising results over the past decade to achieve better drug targeting. Polymeric nanocarriers and lipidic nanoparticles act as a carrier system providing better encapsulation of drugs, site-specific delivery, increased bioavailability and sustained release of drugs. The surface modifications and functionalization of these nanocarrier systems have greatly facilitated targeted drug delivery. The safety and efficacy of these nanocarrier systems have been ascertained by several in vitro and in vivo models. In the present review, we have elaborated on recent developments of nanoparticles as a drug delivery system for Alzheimer's disease, explicitly focusing on polymeric and lipidic nanoparticles.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi275-vi275
Author(s):  
Catherine Vasey ◽  
Vincenzo Taresco ◽  
Stuart Smith ◽  
Cameron Alexander ◽  
Ruman Rahman

Abstract Design and implementation of innovative local drug delivery systems (DDS) may overcome current limitations in GBM treatment, such as the lack of therapeutic drug concentrations reaching residual GBM cells following surgery. Here we describe a novel DDS which utilises a bespoke mechanically engineered spray device, designed for safe surgical use, to deliver a mucoadhesive hydrogel containing chemotherapeutic nanoparticles (NPs) into the tumour resection margins. The overall aim is to spray a NP and polymer solution onto the resection cavity and potentially increase penetration of anti-cancer drugs within the 2 cm reoccurrence zone beyond the infiltrative margin. The mucoadhesive gel of choice, pectin, is currently used in other in vivo applications; however we have repurposed this for the brain. Pectin is biocompatible with GBM and human astrocyte cells in vitro and showed neither toxicity nor inflammation for up to 2 weeks upon orthotopic brain injection. Pectin is biodegradable in artificial CSF and is capable of being sprayed from the engineered device. A panel of polymeric, oil-based and polymer-coated NPs have been developed and optimised to maximise drug encapsulation of etoposide and olaparib as proof-of-concept for combination drug delivery. Etoposide/olaparib was chosen due to cytotoxicity from 5 GBM cell lines, including primary lines isolated from the invasive tumour margin (Mean IC50 of 1.1 µM and 8.3 µM respectively). The optimal NP/drug formulation (based on drug encapsulation, spray capability and bio-adhesiveness) will ultimately be assessed for tolerability and efficacy using orthotopic allograft and xenograft high-grade glioma models, including measurement of penetration of drug/nanoparticle in ex vivo murine and porcine brain using novel hybrid time-of-flight/Orbitrap TM secondary ion mass spectrometer (orbiSIMS) technology.


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