This study was funded by the Mcihael J. Fox Foundation for Parkinson&#39;s Research 2011 Rapid Response Innovations Awards Program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Prior to surgery make sure all procedures to be done are approved by IACUC and any additional ethical or legal authorities and use humane animal treatment practices. This includes using sterile surgery conditions, anesthetizing the mouse using IACUC approved method, lubricating mice eyes with vet ointment during surgery, and providing postsurgical care. Do not proceed with surgery if there is any question whether aspects of the procedure are approved. All procedures performed herein were approved by the Boston University...

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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=Recent+advances+in+blood-brain+barrier+disruption+as+a+CNS+delivery+strategy.">Recent advances in blood-brain barrier disruption as a CNS delivery strategy.</a> AAPS J. 10, 166-177 (2008).</li><li>Merkus, F. H. M., Berg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+nasal+drug+delivery+bypass+the+blood-brain+barrier.">Can nasal drug delivery bypass the blood-brain barrier.</a> Drugs R. D. 8, 133-144 (2007).</li><li>Dhuria, S. V., 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=Intranasal+delivery+to+the+central+nervous+system:+Mechanisms+and+experimental+considerations.">Intranasal delivery to the central nervous system: Mechanisms and experimental considerations.</a> J. Pharm. Sci. 99, 1654-1673 (2010).</li><li>Illum, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nasal+drug+delivery-possibilities,+problems+and+solutions.">Nasal drug delivery-possibilities, problems and solutions.</a> J. Control. 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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=Murine+nasal+septa+for+respiratory+epithelial+air-liquid+interface+cultures.">Murine nasal septa for respiratory epithelial air-liquid interface cultures.</a> BioTechniques. 43, 195-204 (2007).</li><li>Bleier, B. 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The most difficult step of the procedure described herein is the successful transfer of an adequately sized mucosal membrane onto the brain surface. This step is made significantly easier if the harvested nasal septum is large enough and cleaned well. If the ventral portion of the septum is truncated, a new graft should be obtained. The drilling angle should be perpendicular to the mouse head to ensure that the mucosal membrane is not damaged by the drill. If a wider than recommended drilling path is taken it will be muc...

The treatment of neurological and psychiatric disease is severely hindered by the presence of the blood-brain barrier (BBB) which prevents over 95% of all potential pharmaceutical agents from reaching the central nervous system1-3. For example, Glial Derived Neurotrophic Factor (GDNF) has been shown to be effective in treating Parkinson&#39;s Disease when injected directly into the brain, however is ineffective when delivered systemically because it cannot penetrate the BBB4-6.
Numerous approached have been developed to try to circumvent this problem. Improvement in systemic delivery of neurotheraputics has been demonstrated by using drug conjugates containing antibodies selective for transport proteins located on the brain capillary endothelium; however this method has not been shown to be applicable for a broad range of pharmaceuticals7,8. Additionally, osmotic opening of the BBB has been used clinically, however this method suffers from systemic drug dosing as opposed to a more direct delivery to the brain region of interest9. Substantial effort has been put into optimizing transnasal delivery in the hopes of directly targeting the brain10-12. Although some success has been achieved, conclusive results have only been obtained for drugs that possess endogenous receptors, such as insulin13,14. Furthermore the mechanism of transnasal delivery has been controversial with evidence suggesting indirect entry into the brain via olfactory neuron uptake or through the bloodstream11. Direct, transcranial delivery using implantable catheters has been achieved, however this procedure is highly invasive and associated with numerous complications15,16. To date, there is no general, minimally invasive method to deliver high molecular weight compounds into the brain.
Presented herein is a murine surgical procedure that creates a semipermeable interface with the brain. This is accomplished by engrafting a mucosal membrane explant17 over a surgical craniotomy defect in a mouse. Using this procedure it has been shown that soluble compounds up to 500 kDa can be delivered into the central nervous system (directly into brain parenchyma as well as into cerebrospinal fluid) in both a time and molecular weight dependent fashion18. This method of bypassing the BBB is a model for skull base defect repairs in humans which uses vascularized mucosal grafts to repair holes in the skull following transnasal endoscopic surgery19,20.

<table border="0" cellpadding="0" cellspacing="0" style="width:848px;" width="849">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Name of Material/ Equipment</td>
			<td style="width:220px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:263px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">mice</td>
			<td style="width:220px;">Taconic</td>
			<td>C57BL/6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Isoflurane</td>
			<td style="width:220px;">Piramal Healthcare</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Student Fine Scissors</td>
			<td style="width:220px;">Fine Science Tools</td>
			<td>91461-11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">pneumatic drill</td>
			<td style="width:220px;">MTI Dental</td>
			<td style="width:119px;">333-CB</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">drill bit</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">forcepts</td>
			<td style="width:220px;">Fine Science Tools</td>
			<td>91106-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">0.9% Sodium Chloride Injection USP</td>
			<td style="width:220px;">Abbott Laboratories</td>
			<td>4925</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Polystyrene Detri Dish</td>
			<td style="width:220px;">Fisher</td>
			<td>08-757-12</td>
			<td>for temporarily storing graft</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bead Sterilizer</td>
			<td style="width:220px;">Fine Science Tools</td>
			<td>18000-45</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Oxygen/Isoflurane System</td>
			<td style="width:220px;">SurgiVet</td>
			<td>V720100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Temperature Control System</td>
			<td style="width:220px;">Physitemp</td>
			<td style="width:119px;">TCAT-2LV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Small Animal Stereotaxic Instrument</td>
			<td style="width:220px;">KOPF</td>
			<td style="width:119px;">Model 940</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Eye Ointment</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Electric shaver</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Cotton-Tipped Applicators</td>
			<td style="width:220px;">Fisher</td>
			<td>23-400-106</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">7.5% Provadone Iodine</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td>Betadine surgical scrub</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">70% Ethanol</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Surgical Blade Stainless</td>
			<td style="width:220px;">Feather</td>
			<td style="width:119px;">2976#10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Scalpel Handle - #3</td>
			<td style="width:220px;">Fine Science Tools</td>
			<td>10003-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3% Hydogen Peroxide</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td>for cleaning the skull</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Vetbond Tissue Adhesive</td>
			<td style="width:220px;">3M</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">needles</td>
			<td>Becton, Dickinson and Company</td>
			<td>305176</td>
			<td>needle tip cut off and used as well</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">syringes</td>
			<td>Becton, Dickinson and Company</td>
			<td>309597</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">nitrile gloves</td>
			<td style="width:220px;">Denville Scientific Inc</td>
			<td>G4162</td>
			<td>for well closure and protection of graft</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">5-0 Nylon Suture Thread</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Student Halsey Needle Holder</td>
			<td style="width:220px;">Fine Science Tools</td>
			<td>91201-13</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">cyanoacrylate adhesive</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td>commecially available super glue</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dental Cement Kit, 1 lb, Pink Opaque</td>
			<td style="width:220px;">Stoelting</td>
			<td>51458</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">isobutane (2-methylbutane)</td>
			<td style="width:220px;">Aldrich</td>
			<td>M32631</td>
			<td>for dry ice bath</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">dry ice</td>
			<td style="width:220px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

heterotopic mucosal engrafting procedure for direct drug delivery to the brain in mice

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high molecular weight compounds from the bloodstream and into brain tissue. Some direct delivery success in humans has been achieved via implantation of transcranial catheters; however this method is highly invasive and associated with numerous complications. A less invasive alternative would be to dose the brain through a surgically implanted, semipermeable membrane such as the nasal mucosa that is used to repair skull base defects following endoscopic transnasal tumor removal surgery in humans. Drug transfer though this membrane would effectively bypass the BBB and diffuse directly into the brain and cerebrospinal fluid. Inspired by this approach, a surgical approach in mice was developed that uses a donor septal mucosal membrane engrafted over an extracranial surgical BBB defect. This model has been shown to effectively allow the passage of high molecular weight compounds into the brain. Since numerous drug candidates are incapable of crossing the BBB, this model is valuable for performing preclinical testing of novel therapies for neurological and psychiatric diseases.

Obtaining a large enough nasal septum explant is crucial for the subsequent steps. This can be accomplished by drilling at the location on the donor mouse&#39;s skull shown in Figure 1a. Cutting along this path will produce an explant of sufficient the size as shown in Figure 1b. If the drilling depth is not deep enough, the graft will be truncated and it will be hard to obtain a large enough membrane to cover the brain surface. Drilling more laterally than the suggested path is not advi...

Watch this Scientific Journal Video about Heterotopic Mucosal Engrafting Procedure for Direct Drug Delivery to the Brain in Mice at JoVE.com

Heterotopic Mucosal Engrafting Procedure for Direct Drug Delivery to the Brain in Mice

A mouse model of human endoscopic skull base reconstruction has been developed that creates a semipermeable interface between the brain and nose using nasal mucosal grafts. This method allows researchers to study delivery to the central nervous system of high molecular weight therapeutics which are otherwise excluded by the blood-brain barrier when administered systemically.

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high ...

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10.7K vistas.  Boston University.  Un modelo de ratón de la reconstrucción endoscópica de base de cráneo humano se ha desarrollado que crea una interfaz semipermeable entre el cerebro y la nariz con injertos de mucosa nasal. Este método permite a los investigadores estudiar la entrega al sistema nervioso central de la terapéutica de alto peso molecular que se excluyen de otra manera por la barrera sangre-cerebro cuando se administra sistémicamente. 