Name: delivery of antibodies into the murine brain via convection-enhanced delivery
Uploaded: 2019-07-18T13:00:00
Description: Watch this Scientific Journal Video about Delivery of Antibodies into the Murine Brain via Convection-enhanced Delivery at JoVE.com

This work was supported by grants of the University of Zurich (FK-15-057), the Novartis Foundation for medical-biological Research (16C231) and Swiss Cancer Research (KFS-3852-02-2016, KFS-4146-02-2017) to Johannes vom Berg and BRIDGE Proof of Concept (20B1-1_177300) to Linda Schellhammer.

All methods described here have been approved by the Swiss Cantonal Veterinary Office under license number ZH246/15.
1. Preparation of the Step Catheters
<ol>
	<li>Preparation of a fused silica tubing for the step of the catheter
	<ol>
		<li>Cut the fused silica capillary with inner diameter of 0.1 mm and wall thickness of 0.0325 mm tubing to a length of 30 mm.</li>
		<li>Examine the tubing for cracks and heat polish the ends using a microforge to ensure the tubing openings ...

<ol>
	<li>Scherrmann, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+delivery+via+the+blood-brain+barrier.">Drug delivery via the blood-brain barrier.</a> Vascular Pharmacology. 38 (6), 349-354 (2002).</li><li>Barua, N. U., Gill, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+drug+delivery:+prospects+for+glioblastoma+treatment.">Convection-enhanced drug delivery: prospects for glioblastoma treatment.</a> CNS Oncology. 3 (5), 313-316 (2014).</li><li>Bobo, R. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+delivery+of+macromolecules+in+the+brain.">Convection-enhanced delivery of macromolecules in the brain.</a> Proceedings of the National Academy of Sciences of the United States of America. 91 (6), 2076-2080 (1994).</li><li>Morrison, P. F., Laske, D. W., Bobo, H., Oldfield, E. H., Dedrick, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-flow+microinfusion:+tissue+penetration+and+pharmacodynamics.">High-flow microinfusion: tissue penetration and pharmacodynamics.</a> American Journal of Physiology. 266 (1 Pt 2), R292-R305 (1994).</li><li>Zhou, Z., Singh, R., Souweidane, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-Enhanced+Delivery+for+diffuse+intrinsic+pontine+glioma+treatment.">Convection-Enhanced Delivery for diffuse intrinsic pontine glioma treatment.</a> Current Neuropharmacology. 15 (1), 116-128 (2017).</li><li>Barua, N. U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrastriatal+convection-enhanced+delivery+results+in+widespread+perivascular+distribution+in+a+pre-clinical+model.">Intrastriatal convection-enhanced delivery results in widespread perivascular distribution in a pre-clinical model.</a> Fluids and Barriers of the CNS. 9 (1), 2 (2012).</li><li>Shoji, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+convection-enhanced+delivery+of+an+anti-CD40+agonistic+monoclonal+antibody+induces+antitumor+effects+in+mouse+glioma+models.">Local convection-enhanced delivery of an anti-CD40 agonistic monoclonal antibody induces antitumor effects in mouse glioma models.</a> Neuro-Oncology. 18 (8), 1120-1128 (2016).</li><li>Souweidane, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+delivery+for+diffuse+intrinsic+pontine+glioma:+a+single-centre,+dose-escalation,+phase+1+trial.">Convection-enhanced delivery for diffuse intrinsic pontine glioma: a single-centre, dose-escalation, phase 1 trial.</a> The Lancet Oncology. , (2018).</li><li>Zhang, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+immune+checkpoints+in+malignant+glioma.">Targeting immune checkpoints in malignant glioma.</a> Oncotarget. 8 (4), 7157-7174 (2017).</li><li>Barua, N. U., Gill, S. S., Love, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+drug+delivery+to+the+brain:+therapeutic+potential+and+neuropathological+considerations.">Convection-enhanced drug delivery to the brain: therapeutic potential and neuropathological considerations.</a> Brain Pathology. 24 (2), 117-127 (2014).</li><li>Mehta, A. M., Sonabend, A. M., Bruce, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-Enhanced+Delivery.">Convection-Enhanced Delivery.</a> Neurotherapeutics. 14 (2), 358-371 (2017).</li><li>Krauze, M. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reflux-free+cannula+for+convection-enhanced+high-speed+delivery+of+therapeutic+agents.">Reflux-free cannula for convection-enhanced high-speed delivery of therapeutic agents.</a> Journal of Neurosurgery. 103 (5), 923-929 (2005).</li><li>Nash, K. R., Gordon, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection+Enhanced+Delivery+of+Recombinant+Adeno-associated+Virus+into+the+Mouse+Brain.">Convection Enhanced Delivery of Recombinant Adeno-associated Virus into the Mouse Brain.</a> Methods in Molecular Biology. 1382, 285-295 (2016).</li><li>Ohlfest, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+antiangiogenic+gene+therapy+by+nonviral+gene+transfer+using+the+sleeping+beauty+transposon+causes+tumor+regression+and+improves+survival+in+mice+bearing+intracranial+human+glioblastoma.">Combinatorial antiangiogenic gene therapy by nonviral gene transfer using the sleeping beauty transposon causes tumor regression and improves survival in mice bearing intracranial human glioblastoma.</a> Molecular Therapy. 12 (5), 778-788 (2005).</li><li>Yin, D., Forsayeth, J., Bankiewicz, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimized+cannula+design+and+placement+for+convection-enhanced+delivery+in+rat+striatum.">Optimized cannula design and placement for convection-enhanced delivery in rat striatum.</a> Journal of Neuroscience Methods. 187 (1), 46-51 (2010).</li><li>Mamot, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extensive+distribution+of+liposomes+in+rodent+brains+and+brain+tumors+following+convection-enhanced+delivery.">Extensive distribution of liposomes in rodent brains and brain tumors following convection-enhanced delivery.</a> Journal of Neuro-Oncology. 68 (1), 1-9 (2004).</li><li>Saito, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+affinity+of+the+infusate+affects+the+distribution+volume+during+convection-enhanced+delivery+into+rodent+brains:+implications+for+local+drug+delivery.">Tissue affinity of the infusate affects the distribution volume during convection-enhanced delivery into rodent brains: implications for local drug delivery.</a> Journal of Neuroscience Methods. 154 (1-2), 225-232 (2006).</li><li>Oh, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+distribution+of+small+molecules+and+viral+vectors+in+the+murine+brain+using+a+hollow+fiber+catheter.">Improved distribution of small molecules and viral vectors in the murine brain using a hollow fiber catheter.</a> Journal of Neurosurgery. 107 (3), 568-577 (2007).</li><li>Barua, N. U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+implantable+catheter+system+with+transcutaneous+port+for+intermittent+convection-enhanced+delivery+of+carboplatin+for+recurrent+glioblastoma.">A novel implantable catheter system with transcutaneous port for intermittent convection-enhanced delivery of carboplatin for recurrent glioblastoma.</a> Drug Delivery. 23 (1), 167-173 (2016).</li><li>Rosenbluth, K. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+an+in-dwelling+cannula+for+convection-enhanced+delivery.">Design of an in-dwelling cannula for convection-enhanced delivery.</a> Journal of Neuroscience Methods. 196 (1), 118-123 (2011).</li><li>Debinski, W., Tatter, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+delivery+for+the+treatment+of+brain+tumors.">Convection-enhanced delivery for the treatment of brain tumors.</a> Expert Review of Neurotherapeutics. 9 (10), 1519-1527 (2009).</li><li>MacKay, J. A., Deen, D. F., Szoka, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+in+brain+of+liposomes+after+convection+enhanced+delivery;+modulation+by+particle+charge,+particle+diameter,+and+presence+of+steric+coating.">Distribution in brain of liposomes after convection enhanced delivery; modulation by particle charge, particle diameter, and presence of steric coating.</a> Brain Research. 1035 (2), 139-153 (2005).</li><li>Chen, Z. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+realistic+brain+tissue+phantom+for+intraparenchymal+infusion+studies.">A realistic brain tissue phantom for intraparenchymal infusion studies.</a> Journal of Neurosurgery. 101 (2), 314-322 (2004).</li><li>Sampson, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poor+drug+distribution+as+a+possible+explanation+for+the+results+of+the+PRECISE+trial.">Poor drug distribution as a possible explanation for the results of the PRECISE trial.</a> Journal of Neurosurgery. 113 (2), 301-309 (2010).</li><li>Wick, W., Weller, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trabedersen+to+target+transforming+growth+factor-beta:+when+the+journey+is+not+the+reward,+in+reference+to+Bogdahn+et+al.+(Neuro-Oncology+2011;13:132-142).">Trabedersen to target transforming growth factor-beta: when the journey is not the reward, in reference to Bogdahn et al. (Neuro-Oncology 2011;13:132-142).</a> Neuro-Oncology. 13 (5), 559-560 (2011).</li><li>Saito, R., Tominaga, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convection-enhanced+delivery+of+therapeutics+for+malignant+gliomas.">Convection-enhanced delivery of therapeutics for malignant gliomas.</a> Neurologia Medico-Chirurgica. 57 (1), 8-16 (2017).</li><li>Bedussi, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clearance+from+the+mouse+brain+by+convection+of+interstitial+fluid+towards+the+ventricular+system.">Clearance from the mouse brain by convection of interstitial fluid towards the ventricular system.</a> Fluids Barriers CNS. 12, 23 (2015).</li><li>Noroxe, D. S., Poulsen, H. S., Lassen, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hallmarks+of+glioblastoma:+a+systematic+review.">Hallmarks of glioblastoma: a systematic review.</a> ESMO Open. 1 (6), e000144 (2016).</li><li>Boucher, Y., Salehi, H., Witwer, B., Harsh, G. R. t., Jain, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interstitial+fluid+pressure+in+intracranial+tumours+in+patients+and+in+rodents.">Interstitial fluid pressure in intracranial tumours in patients and in rodents.</a> British Journal of Cancer. 75 (6), 829-836 (1997).</li><li>Glushakova, O. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospective+clinical+biomarkers+of+caspase-mediated+apoptosis+associated+with+neuronal+and+neurovascular+damage+following+stroke+and+other+severe+brain+injuries:+Implications+for+chronic+neurodegeneration.">Prospective clinical biomarkers of caspase-mediated apoptosis associated with neuronal and neurovascular damage following stroke and other severe brain injuries: Implications for chronic neurodegeneration.</a> Brain Circulation. 3 (2), 87-108 (2017).</li><li>Vom Berg, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+IL-12/IL-23+signaling+reduces+Alzheimer's+disease-like+pathology+and+cognitive+decline.">Inhibition of IL-12/IL-23 signaling reduces Alzheimer's disease-like pathology and cognitive decline.</a> Nature Medicine. 18 (12), 1812-1819 (2012).</li><li>Vom Berg, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intratumoral+IL-12+combined+with+CTLA-4+blockade+elicits+T+cell-mediated+glioma+rejection.">Intratumoral IL-12 combined with CTLA-4 blockade elicits T cell-mediated glioma rejection.</a> Journal of Experimental Medicine. 210 (13), 2803-2811 (2013).</li><li>Kurdi, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+administration+of+the+mTORC1+inhibitor+everolimus+induces+tolerance+and+decreases+autophagy+in+mice.">Continuous administration of the mTORC1 inhibitor everolimus induces tolerance and decreases autophagy in mice.</a> British Journal of Pharmacology. 173 (23), 3359-3371 (2016).</li></ol>

Convection-enhanced delivery, or pressure-mediated drug infusion into the brain, was first proposed in the early 19903. This approach promises perfusion of large brain volumes behind the blood brain barrier in a controlled manner2. However, so far, only a few clinical trials have been performed using this approach, partially because CED in a clinical setup has shown to be technically demanding24,25. Recent developme...

The blood brain barrier (BBB) forms a semipermeable border separating the central nervous system (CNS) from the blood circulation. Reaching the CNS with therapeutics is however necessary in context of various diseases, like brain tumors, Alzheimer&#8217;s disease (AD) or Parkinson&#8217;s disease (PD) among others1. This becomes important in the development of new therapies, especially if the tested drug exhibits poor BBB permeability or its systemic exposure can lead to dangerous toxicity1,2. Some of the clinically used antibodies display both of these features. A solution to this problem would be to deliver the therapeutics directly behind the BBB.
Convection-enhanced delivery (CED) is a neurosurgical technique enabling effective perfusion of large brain volumes. This is achieved by surgically installing one or more catheters in the target area. During the drug application, a pressure gradient is formed at the opening of the catheter, which becomes the driving force of the infusate dispersion in the tissue3,4. It is thus the duration of infusion and not the diffusion coefficients that determine the perfusion range2,4,5. This provides uniform delivery of the infusate over a much larger brain volume compared to conventional, diffusion based intracerebral injection methods2,6. At the same time, this delivery modality has a lower risk of tissue damage2. Accordingly, CED can enable safe and efficacious administration of conventional chemotherapeutics for treatment of CNS tumors, as well as delivery of immunomodulatory agents or agonistic and antagonistic antibodies in a multitude of other CNS disorders2,7,8,9. CED is currently tested in therapies of Parkinson&#8217;s disease, Alzheimer&#8217;s disease, as well as high-grade glioma2,7,8,10,11.
Catheter design and the injection regimen are among the most important factors influencing the outcome of CED 10,12,13,14,15,16. Furthermore, it requires specific physicochemical properties of the infusate, including moderate size of the particles, an anionic charge, and low tissue affinity 10,17. Each of these parameters has to be potentially adjusted according to the histological features of the brain region to be targeted2,10,17.
Here we describe methodology for performing CED of an antibody solution into the caudate putamen (striatum) of mice. Furthermore, the protocol includes preparation of step catheters in a laboratory setup, testing them in vitro and performing the CED.
There are multiple catheter designs available in the literature, differing by the shape of the cannula, the materials used and the number of catheter openings12,15,18,19,20,21,22. We are using a step catheter made of a fused silica capillary protruding 1 mm from a blunt end metal needle. This catheter design can be easily manufactured in a research laboratory and reproducibly gives good CED results when tested in vitro with agarose blocks with physical parameters resembling brain parenchyma in vivo23.
Moreover, we implement a ramping regimen for delivering 5 &#181;L of infusate in vivo. In such a protocol the injection rate is increased from 0.2 &#181;L/min to a maximum of 0.8 &#181;L/min, thus minimizing chances of infusate reflux along the catheter as well as risk of tissue damage16. Using this protocol, we have successfully administered mice with up to 20 &#181;g of antibody in 5 &#181;L of PBS over the course of 11 min 30 s.
The protocol can be readily adjusted for other infusion volumes or for injecting various other substances, e.g. chemotherapeutics, cytokines, viral particles or liposomes2,10,14,18,22. In case of using infusate with drastically different physicochemical properties compared to a phosphate buffered saline (PBS) or artificial cerebrospinal fluid (aCSF) solution of antibodies, additional validation steps are recommended. For catheter assembly, validation and CED, we describe all steps using a stereotactic robot with a drill and injection unit mounted onto a regular stereotactic frame. This procedure can also be performed with a manual stereotactic frame connected to programmable microinfusion pump that can drive the described glass microsyringes.

<table>
	<tbody>
		<tr>
			<td>10 &#956;L syringe</td>
			<td>Hamilton</td>
			<td>7635-01</td>
			<td></td>
		</tr>
		<tr>
			<td>27 G blunt end needle</td>
			<td>Hamilton</td>
			<td>7762-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Promega</td>
			<td>V3121</td>
			<td></td>
		</tr>
		<tr>
			<td>Atipamezol</td>
			<td>Janssen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bone wax</td>
			<td>Braun</td>
			<td>1029754</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Indivior Schweiz AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Carprofen</td>
			<td>Pfizer AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dental drill bits, steel, size ISO 009</td>
			<td>Hager &#38; Meisinger</td>
			<td>1RF009</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol 100%</td>
			<td>Reuss-Chemie AG</td>
			<td>179-VL03K-/1</td>
			<td></td>
		</tr>
		<tr>
			<td>Fentanyl</td>
			<td>Helvepharm AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FITC-Dextran, 2000 kDa</td>
			<td>Sigma Aldrich</td>
			<td>FD2000S</td>
			<td></td>
		</tr>
		<tr>
			<td>Flumazenil</td>
			<td>Labatec Pharma AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde</td>
			<td>Sigma Aldrich</td>
			<td>F8775-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>High viscosity cyanoacrylate glue</td>
			<td>Migros</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Iodine solution</td>
			<td>Mundipharma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medetomidin</td>
			<td>Orion Pharma AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microforge</td>
			<td>Narishige</td>
			<td>MF-900</td>
			<td></td>
		</tr>
		<tr>
			<td>Midazolam</td>
			<td>Roche Pharma AG</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ophthalmic ointment</td>
			<td>Bausch + Lomb</td>
			<td>Vitamin A Blache</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>ThermoFischer Scientific</td>
			<td>10010023</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyclonal goat anti-rat IgG (H+L) antibody coupled with Alexa Fluor 647</td>
			<td>Jackson Immuno</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpels</td>
			<td>Braun</td>
			<td>BB518</td>
			<td></td>
		</tr>
		<tr>
			<td>Silica tubing internal diameter 0.1 mm, wall thickness of 0.0325 mm</td>
			<td>Postnova</td>
			<td>Z-FSS-100165</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereotactic frame for mice</td>
			<td>Stoelting</td>
			<td>51615</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereotactic robot</td>
			<td>Neurostar</td>
			<td>Drill and Injection Robot</td>
			<td></td>
		</tr>
		<tr>
			<td>Succrose</td>
			<td>Sigma Aldrich</td>
			<td>S0389-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Topical tissue adhesive</td>
			<td>Zoetis</td>
			<td>GLUture</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue</td>
			<td>ThermoFischer Scientific</td>
			<td>15250061</td>
			<td></td>
		</tr>
		<tr>
			<td>Water</td>
			<td>Bichsel</td>
			<td>1000004</td>
			<td></td>
		</tr>
	</tbody>
</table>

delivery of antibodies into the murine brain via convection-enhanced delivery

Convection-enhanced delivery (CED) is a neurosurgical technique enabling effective perfusion of large brain volumes using a catheter system. Such an approach provides a safe delivery method by-passing the blood brain barrier (BBB), thus allowing treatment with therapeutics with poor BBB-permeability or those for which systemic exposure is not desired, e.g., due to toxicity. CED requires optimization of the catheter design, injection protocol, and properties of the infusate. With this protocol we describe how to perform CED of a solution containing up to 20 &#181;g of an antibody into the caudate putamen of mice. It describes preparation of step catheters, testing them in vitro and performing the CED in mice using a ramping injection program. The protocol can be readily adjusted for other infusion volumes and can be used for injecting various tracers or pharmacologically active or inactive substances, including chemotherapeutics, cytokines, viral particles, and liposomes.

This protocol enables preparation of step catheters (Figure 1) for use in the CED procedure in a laboratory environment. In order to control the catheters for leakage, reflux along the needle tract and clogging, we recommend performing injections of a dye, e.g., trypan blue solution, into an agarose block. Figure 3 depicts a cloud of trypan blue forming after injection of 1 &#181;L at 0.5 &#181;L/minute using a CED catheter (Figure 3A</stron...

Watch this Scientific Journal Video about Delivery of Antibodies into the Murine Brain via Convection-enhanced Delivery at JoVE.com

Delivery of Antibodies into the Murine Brain via Convection-enhanced Delivery

Convection-enhanced delivery (CED) is a method enabling effective delivery of therapeutics into the brain by direct perfusion of large tissue volumes. The procedure requires the use of catheters and an optimized injection procedure. This protocol describes a methodology for CED of an antibody into a mouse brain.

Convection-enhanced delivery (CED) is a neurosurgical technique enabling effective perfusion of large brain volumes using a catheter system. Such an ...

This protocol can be used to perform convection-enhanced delivery in small rodents using a step catheter system for the adjustable uniform perfusion of target brain regions. The advantage of convection-enhanced delivery is that it allows delivery of substances into the region of interest bypassing the blood-brain barrier with little tissue damage or reflux. This technique is primarily useful for delivery of therapeutic substances such as antibodies into the brain.And can therefore be used to target many neurological conditions. Demonstrating the procedure will be Michal Beffinger, a post-doc from my laboratory. Begin by cutting a piece of fused silica capillary tubing with an inner diameter of 0.1 millimeter and a wall thickness of 0.325 millimeter to a length of 30 millimeters.After examining the tubing for cracks use a microforge to heat polish the ends to ensure the tubing openings have a smooth surface. Next, mount a 27-gauge needle onto a 10 micro liter syringe and place the syringe in a stereotactic robot. Use the robot to move the syringe over a hard surface and touch the surface with the needle tip.After noting this position elevate the needle to enable placement of the fused silica capillary inside of the needle such that 20 millimeters of the capillary protrudes from the needle. Use a pipette to evenly spread two microliters of high viscosity cyanoacrylate adhesive over the capillary starting from the metal needle and finishing ten millimeters above the lower end of the capillary. Use the stereotactic robot to lower the metal needle until the tip of the needle is one millimeter over the reference surface to fix the fused silica capillary in the metal needle forming a one millimeter step from the tip of the metal needle.Remove any excess glue forming at the end of the metal needle to avoid planting the catheter step. Check the tip under a microscope to confirm that all of the excess glue has been removed. Then wait 15 minutes for the glue to harden and remove the syringe with the catheter from the robot.For step catheter testing cut solidified 0.6%agarose gel into 20 by 20 millimeter blocks and manually fill the step catheter syringe with 10 microliters of filtered 0.4%trypan blue solution. Using the stereotactic robot, dispense one microliter of dye at 0.2 micro liters per minute to assess the sealing of the step of the catheter during the fixation procedure. The trypan blue solution should be visible solely on the tip of the catheter.Wipe away the dye with a paper tissue and place an agarose block in the stereotactic robot. Calibrate the robot said that the tip of the catheter is referenced against the surface of the agarose block. Set a proportion sequence of injection volumes according to the specific experimental plan.To inject the solution into the murine caudate putamen, set the injection to a one millimeter frontal and one and a half to two millimeter lateral from bregma position at a depth of 3.5 millimeters. When the needle is in position start the convection enhanced delivery procedure and inject five microliters of trypan blue solution into the agarose block. Assess the shape of the trypan blue cloud in the agarose and for potential leakage along the catheter tract.No major backflow over the tip of the metal needle should be visible. After the injection leave the catheter in place for two minutes before retracting the needle at one millimetre per minute to ensure a proper dispersion of the fluid into the brain and sealing of the injection tract during the removal. Place a new agarose block into the robot and start a second injection of one microliter at 0.2 micro liters per minute to assess clogging of the catheter within the agarose.The trypan blue should again form a cloud from the tip of the catheter immediately after the start of the injection. Then assess whether the leftover volume in the syringe corresponds to 3 microliters as any variations might indicate a leakage of fluid through the catheter mounting or syringe plunger. For antibody injection into the murine striatum confirm a lack of response to skin pinch in an anesthetized Mouse and shave the head with a hair trimmer.Disinfect the skin with cotton swabs soaked in iodine solution. Use a scalpel to make a 10 millimeter skin incision along the cranial midline finishing at the eye level. Fix the mouse in the stereotactic frame using the nose clamp and ear bars, taking care that the skull surface is horizontal and tightly secured.Place the syringe in the stereotactic robot and synchronize the drill bit with the tip of the catheter on a reference point. Use forceps to retract the skin and localize bregma on the skull surface. Reference bregma in the software using the tip of the drill bit and move the drill to a one millimeter frontal and two millimeter lateral from bregma position.Drill a burr hole taking care not to damage the dura mater and move the syringe over the burr hole. Dispense 0.5 to one microliter from the syringe to ensure that no air bubbles are left in the catheter. Start the convection enhanced delivery as demonstrated, observing the skull surface for any traces of fluid backflow from the injection spot.At the end of the delivery and catheter removal start the injection pump at 0.2 micro liters per minute to check for evidence of catheter clogging during the injection. If no clogging occurred a droplet of injection mix should immediately be observed coming from the catheter tip. In this image of a cloud of trypan blue forming after the injection of one microliter of dye at 0.5 micro liters per minute using a convection enhanced catheter as demonstrated, no reflux along the needle tract was visible over the beginning of the catheter step.And the dispersed cloud formed a desired spherical shape. In this image using a blunt end needle however, significant reflux could be observed. Notably, convection enhanced delivery enables the perfusion of large volumes into the murine brain in a uniform and less tissue damaging manner compared to conventional injection.In both types of delivery there is a typical distribution profile of antibody and dextran particles over the corpus callosum. However, the dispersion profile of the injected antibody is more diffused than is observed for the high molecular weight dextran after convection enhanced delivery, exemplifying differences in distribution between different infusates. As the catheter can potentially clog during the brain infusion, it is important to check it immediately after by slowly dispensing a small volume of infusate.This procedure can serve as a way to deliver pharmacologically active compounds to the brain and should be followed by close monitoring of disease symptoms and expected side effects. This technique enables the infusion of a precise brain region with therapeutics including antibodies, opening new possibilities for the development of central nervous system targeted therapies.

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Research

JoVE Journal

Neuroscience

Targeting of Deep Brain Structures with Microinjections for Delivery of Drugs, Viral Vectors, or Cell Transplants

Microinjections into the brain parenchyma are important procedures to deliver drugs, viral vectors or cell transplants.  The brain lesion that an injecting needle produces during its trajectory is a major concern especially in the mouse brain for not only the brain is small but also sometimes multiple injections are needed.  We show here a method to produce glass capillary needles with a 50-&mu;m lumen which significantly reduces the brain damage and allows a precise targeting into the rodent brain. This method allows a delivery of small volumes (from 20 to 100 nl), reduces bleeding risks, and minimizes passive diffusion of drugs into the brain parenchyma. By using different size of capillary glass tubes, or changing the needle lumen, several types of substances and cells can be injected. Microinjections with a glass capillary tube represent a significant improvement in injection techniques and deep brain targeting with minimal collateral damage in small rodents.

In this article, we show a method to make glass capillary needles with a 50-&mu;m lumen. This technique significantly reduces the brain damage, minimizes passive diffusion of drugs and allows a precise targeting into the rodent brain.

Microinjections into the brain parenchyma are important procedures to deliver drugs, viral vectors or cell transplants.  The brain lesion that an ...

Gene Delivery to Postnatal Rat Brain by Non-ventricular Plasmid Injection and Electroporation

Creation of transgenic animals is a standard approach in studying functions of a gene of interest in vivo. However, many knockout or transgenic animals are not viable in those cases where the modified gene is expressed or deleted in the whole organism. Moreover, a variety of compensatory mechanisms often make it difficult to interpret the results. The compensatory effects can be alleviated by either timing the gene expression or limiting the amount of transfected cells.
The method of postnatal non-ventricular microinjection and in vivo electroporation allows targeted delivery of genes, siRNA or dye molecules directly to a small region of interest in the newborn rodent brain. In contrast to conventional ventricular injection technique, this method allows transfection of non-migratory cell types. Animals transfected by means of the method described here can be used, for example, for two-photon in vivo imaging or in electrophysiological experiments on acute brain slices.

This protocol describes a non-viral method of delivery of genetic constructs to a certain area of living rodent brain. The method consists of plasmid preparation, micropipette fabrication, neonatal rat pup surgery, microinjection of the construct, and in vivo electroporation.

Creation of transgenic animals is a standard approach in studying functions of a gene of interest in vivo. However, many knockout or transgenic animals ...

Efficient Gene Delivery into Multiple CNS Territories Using In Utero Electroporation

The ability to manipulate gene expression is the cornerstone of modern day experimental embryology, leading to the elucidation of multiple developmental pathways. Several powerful and well established transgenic technologies are available to manipulate gene expression levels in mouse, allowing for the generation of both loss- and gain-of-function models. However, the generation of mouse transgenics is both costly and time consuming. Alternative methods of gene manipulation have therefore been widely sought. In utero electroporation is a method of gene delivery into live mouse embryos1,2 that we have successfully adapted3,4. It is largely based on the success of in ovo electroporation technologies that are commonly used in chick5. Briefly, DNA is injected into the open ventricles of the developing brain and the application of an electrical current causes the formation of transient pores in cell membranes, allowing for the uptake of DNA into the cell. In our hands, embryos can be efficiently electroporated as early as embryonic day (E) 11.5, while the targeting of younger embryos would require an ultrasound-guided microinjection protocol, as previously described6. Conversely, E15.5 is the latest stage we can easily electroporate, due to the onset of parietal and frontal bone differentiation, which hampers microinjection into the brain. In contrast, the retina is accessible through the end of embryogenesis. Embryos can be collected at any time point throughout the embryonic or early postnatal period. Injection of a reporter construct facilitates the identification of transfected cells.
To date, in utero electroporation has been most widely used for the analysis of neocortical development1,2,3,4. More recent studies have targeted the embryonic retina7,8,9 and thalamus10,11,12. Here, we present a modified in utero electroporation protocol that can be easily adapted to target different domains of the embryonic CNS. We provide evidence that by using this technique, we can target the embryonic telencephalon, diencephalon and retina. Representative results are presented, first showing the use of this technique to introduce DNA expression constructs into the lateral ventricles, allowing us to monitor progenitor maturation, differentiation and migration in the embryonic telencephalon. We also show that this technique can be used to target DNA to the diencephalic territories surrounding the 3rd ventricle, allowing the migratory routes of differentiating neurons into diencephalic nuclei to be monitored. Finally, we show that the use of micromanipulators allows us to accurately introduce DNA constructs into small target areas, including the subretinal space, allowing us to analyse the effects of manipulating gene expression on retinal development.

Efficient Gene Delivery into Multiple CNS Territories Using In Utero Electroporation

In utero electroporation allows for rapid gene delivery in a spatially- and temporally-controlled manner in the developing central nervous system (CNS). Here we describe a highly adaptable in utero electroporation protocol that can be used to deliver expression constructs into multiple embryonic CNS domains, including the telencephalon, diencephalon and retina.

The ability to manipulate gene expression is the cornerstone of modern day experimental embryology, leading to the elucidation of multiple developmental ...

Direct Intraventricular Delivery of Drugs to the Rodent Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video.
The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.

We describe a method to target drugs to the central nervous system by either implanting a catheter or performing a bolus injection into the right lateral ventricle in mice. We focus specifically on the delivery of antisense oligonucleotides. This technique is readily adaptable to other drugs and to rats.

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses ...

Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus

Alzheimer&#8217;s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the over-production of amyloid-beta and the deposition of amyloid-beta plaques in brain regions of the afflicted individuals. Throughout the years scientists have generated numerous Alzheimer&#8217;s disease mouse models that attempt to replicate the amyloid-beta pathology. Unfortunately, the mouse models only selectively mimic the disease features. Neuronal death, a prominent effect in the brains of Alzheimer&#8217;s disease patients, is noticeably lacking in these mice. Hence, we and others have employed a method of directly infusing soluble oligomeric species of amyloid-beta - forms of amyloid-beta that have been proven to be most toxic to neurons - stereotaxically into the brain. In this report we utilize male C57BL/6J mice to document this surgical technique of increasing amyloid-beta levels in a select brain region. The infusion target is the dentate gyrus of the hippocampus because this brain structure, along with the basal forebrain that is connected by the cholinergic circuit, represents one of the areas of degeneration in the disease. The results of elevating amyloid-beta in the dentate gyrus via stereotaxic infusion reveal increases in neuron loss in the dentate gyrus within 1 week, while there is a concomitant increase in cell death and cholinergic neuron loss in the vertical limb of the diagonal band of Broca of the basal forebrain. These effects are observed up to 2 weeks. Our data suggests that the current amyloid-beta infusion model provides an alternative mouse model to address region specific neuron death in a short-term basis. The advantage of this model is that amyloid-beta can be elevated in a spatial and temporal manner.

Here, we present a protocol for direct stereotaxic brain infusion of amyloid-beta. This methodology provides an alternative in vivo mouse model to address the short-term effects of amyloid-beta on brain neurons.

Alzheimer&#8217;s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the ...

Implantation of Miniosmotic Pumps and Delivery of Tract Tracers to Study Brain Reorganization in Pathophysiological Conditions

Pharmacological treatment in animal models of cerebral disease imposes the problem of repeated injection protocols that may induce stress in animals and result in impermanent tissue levels of the drug. Additionally, drug delivery to the brain is delicate due to the blood brain barrier (BBB), thus significantly reducing intracerebral concentrations of selective drugs after systemic administration. Therefore, a system that allows both constant drug delivery without peak levels and circumvention of the BBB is in order to achieve sufficiently high intracerebral concentrations of drugs that are impermeable to the BBB. In this context, miniosmotic pumps represent an ideal system for constant drug delivery at a fixed known rate that eludes the problem of daily injection stress in animals and that may also be used for direct brain delivery of drugs. Here, we describe a method for miniosmotic pump implantation and post operatory care that should be given to animals in order to successfully apply this technique. We embed the aforementioned experimental paradigm in standard procedures that are used for studying neuroplasticity within the brain of C57BL6 mice. Thus, we exposed animals to 30 min brain infarct and implanted with miniosmotic pumps connected to the skull via a cannula in order to deliver a pro-plasticity drug. Behavioral testing was done during 30 days of treatment. After removal the animals received injections of anterograde tract tracers to analyze neuronal plasticity in the chronic phase of recovery. Results indicated that neuroprotection by the delivered drug was accompanied with increase in motor fibers crossing the midline of the brain at target structures. The results affirm the value of these techniques for drug administration and brain plasticity studies in modern neuroscience.

In order to study brain reorganization under pathological conditions we used miniosmotic pumps for direct protein delivery into the brain circumventing the blood brain barrier. Tract tracers are then injected to study alterations in brain connectivity under the influence of the protein.

Pharmacological treatment in animal models of cerebral disease imposes the problem of repeated injection protocols that may induce stress in animals and ...

Designing, Packaging, and Delivery of High Titer CRISPR Retro and Lentiviruses via Stereotaxic Injection

Replication defective lentiviruses or retroviruses are capable of stably integrating transgenes into the genome of an infected host cell. This technique has been widely used to encode fluorescent proteins, opto- or chemo-genetic controllers of cell activity, or heterologous expression of human genes in model organisms. These viruses have also successfully been used to deliver recombinases to relevant target sites in transgenic animals, or even deliver small hairpin or micro RNAs in order to manipulate gene expression. While these techniques have been fruitful, they rely on transgenic animals (recombinases) or frequently lack high efficacy and specificity (shRNA/miRNA). In contrast, the CRISPR/Cas system uses an exogenous Cas nuclease which targets specific sites in an organism's genome via an exogenous guide RNA in order to induce double stranded breaks in DNA. These breaks are then repaired by non-homologous end joining (NHEJ), producing insertion and deletion (indel) mutations that can result in deleterious missense or nonsense mutations. This manuscript provides detailed methods for the design, production, injection, and validation of single lenti/retro virus particles that can stably transduce neurons to express a fluorescent reporter, Cas9, and sgRNAs to knockout genes in a model organism.

The CRISPR/Cas9 system offers the potential to make targeted genome editing accessible and affordable to the scientific community. This protocol is intended to demonstrate how to create viruses that will knockout a gene of interest using the CRISPR/Cas9 system, and then inject them stereotaxically into the adult mouse brain.

Replication defective lentiviruses or retroviruses are capable of stably integrating transgenes into the genome of an infected host cell. This technique ...

Mouse Microsurgery Infusion Technique for Targeted Substance Delivery into the CNS via the Internal Carotid Artery

Animal models of central nervous system (CNS) diseases and, consequently, blood-brain barrier disruption diseases, require the delivery of exogenous substances into the brain. These exogenous substances may induce injurious impact or constitute therapeutic strategy. The most common delivery methods of exogenous substances into the brain are based on systemic deliveries, such as subcutaneous or intravenous routes. Although commonly used, these approaches have several limitations, including low delivery efficacy into the brain. In contrast, surgical methods that locally deliver substances into the CNS are more specific and prevent the uptake of the exogenous substances by other organs. Several surgical methods for CNS delivery are available; however, they tend to be very traumatic. Here, we describe a mouse infusion microsurgery technique, which effectively delivers substances into the brain via the internal carotid artery, with minimal trauma and no interference with normal CNS functionality.

Mouse Microsurgery Infusion Technique for Targeted Substance Delivery into the CNS via the Internal Carotid Artery

The present protocol describes a mouse microsurgery infusion technique, which effectively delivers substances directly into the brain via the internal carotid artery.

Animal models of central nervous system (CNS) diseases and, consequently, blood-brain barrier disruption diseases, require the delivery of exogenous ...

Convection Enhanced Delivery of Optogenetic Adeno-associated Viral Vector to the Cortex of Rhesus Macaque Under Guidance of Online MRI Images

In non-human primate (NHP) optogenetics, infecting large cortical areas with viral vectors is often a difficult and time-consuming task. Here, we demonstrate the use of magnetic resonance (MR)-guided convection enhanced delivery (CED) of optogenetic viral vectors into primary somatosensory (S1) and motor (M1) cortices of macaques to obtain efficient, widespread cortical expression of light-sensitive ion channels. Adeno-associated viral (AAV) vectors encoding the red-shifted opsin C1V1 fused to yellow fluorescent protein (EYFP) were injected into the cortex of rhesus macaques under MR-guided CED. Three months post-infusion, epifluorescent imaging confirmed large regions of optogenetic expression (&#62;130 mm2) in M1 and S1 in two macaques. Furthermore, we were able to record reliable light-evoked electrophysiology responses from the expressing areas using micro-electrocorticographic arrays. Later histological analysis and immunostaining against the reporter revealed widespread and dense optogenetic expression in M1 and S1 corresponding to the distribution indicated by epifluorescent imaging. This technique enables us to obtain expression across large areas of the cortex within a shorter period of time with minimal damage compared to the traditional techniques and can be an optimal approach for optogenetic viral delivery in large animals such as NHPs. This approach demonstrates great potential for network-level manipulation of neural circuits with cell-type specificity in animal models evolutionarily close to humans.&#160;

Here, we demonstrate magnetic resonance (MR)-guided convection enhanced delivery (CED) of viral vectors into the cortex as an efficient and simplified approach for achieving optogenetic expression across large cortical areas in the macaque brain.

In non-human primate (NHP) optogenetics, infecting large cortical areas with viral vectors is often a difficult and time-consuming task. Here, we ...

Electrophoretic Delivery of &#x3B3;-aminobutyric Acid (GABA) into Epileptic Focus Prevents Seizures in Mice

Epilepsy is a group of neurological disorders which affects millions of people worldwide. Although treatment with medication is helpful in 70% of the cases, serious side effects affect the quality of life of patients. Moreover, a high percentage of epileptic patients are drug resistant; in their case, neurosurgery or neurostimulation are necessary. Therefore, the major goal of epilepsy research is to discover new therapies which are either capable of curing epilepsy without side effects or preventing recurrent seizures in drug-resistant patients. Neuroengineering provides new approaches by using novel strategies and technologies to find better solutions to cure epileptic patients at risk.
As a demonstration of a novel experimental protocol in an acute mouse model of epilepsy, a direct in situ electrophoretic drug delivery system is used. Namely, a neural probe incorporating a microfluidic ion pump (&#181;FIP) for on-demand drug delivery and simultaneous recording of local neural activity is implanted and demonstrated to be capable of controlling 4-aminopyridine-induced (4AP-induced) seizure-like event (SLE) activity. The &#947;-aminobutyric acid (GABA) concentration is kept in the physiological range by the precise control of GABA delivery to reach an antiepileptic effect in the seizure focus but not to cause overinhibition-induced rebound bursts. The method allows both the detection of pathological activity and intervention to stop seizures by delivering inhibitory neurotransmitters directly to the epileptic focus with precise spatiotemporal control.
As a result of the developments to the experimental method, SLEs can be induced in a highly localized manner that allows seizure control by the precisely tuned GABA delivery at the seizure onset.

Electrophoretic Delivery of &#947;-aminobutyric Acid GABA into Epileptic Focus Prevents Seizures in Mice

The challenge of epilepsy research is to develop novel treatments for patients where classical therapy is inadequate. Using a new protocol&#8212;with the help of an implantable drug delivery system&#8212;we are able to control seizures in anesthetized mice by the electrophoretic delivery of GABA into the epileptic focus.

Epilepsy is a group of neurological disorders which affects millions of people worldwide. Although treatment with medication is helpful in 70% of the ...