Name: mouse microsurgery infusion technique for targeted substance delivery into the cns via the internal carotid artery
Uploaded: 2017-01-31T14:00:00.000+00:00
Duration: 6 min 41 s
Description: Watch this Scientific Journal Video about Mouse Microsurgery Infusion Technique for Targeted Substance Delivery into the CNS via the Internal Carotid Artery at JoVE.com

We would like to thank Dr. Lei Chen (Icahn School of Medicine at Mount Sinai, NY) who first established the use of this model in our laboratory, and to Dr. Gretchen Wolff (German Cancer Research Center, Heidelberg, Germany) for disseminating the technique in our laboratory. Supported in part by HL126559, DA039576, MH098891, MH63022, MH072567, DA027569, and NSC 2015/17/B/NZ7/02985.

The procedures involved in the following protocol have been approved by the University of Miami Institutional Animal Care and Use Committee (IACUC). In addition, all procedures are being conducted in facilities approved by the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC).
1. Preparation of Mice for Surgery
<ol>
	<li>Anesthetize mouse with isoflurane mixed with oxygen, using a laboratory anesthesia system. Use isoflurane at setting between 4-5%&#160;and oxygen flow at 2 L/min on the commercial machine (See Materials Table). Transfer the animal to the surgery surface, under a stereomicroscope, and sustain anesthesia using a nose cone (use isoflurane setting 1.5 - 2.5 and oxygen flow at 2 L/min).
	<ol>
		<li>Ensure that the mouse respiratory rate is around 1 - 2 respiration/sec without gasping. In addition, ensure that the animal does not exhibit whiskers stimulation reaction and pedal reflex (toe pinch). Monitor respiration rate and effort during the surgery, at least every 5 min.&#160;Follow specific Institutional Animal Care and Use Committee and veterinary guidelines for rodent anesthesia monitoring.</li>
	</ol>
	</li>
	<li>Apply a drop of ophthalmic lubricant on each eye using a sterile swab in order to prevent dryness.&#160;Administration of anti-inflammatory and analgesic to alleviate discomfort is recommended.</li>
	<li>With the animal lying on its back, maintain anesthesia using a nose cone.</li>
	<li>Clean the animal&#39;s neck area by wiping the area three times&#160;with ethanol 70% and chlorhexidine. Shave the animal&#39;s surgery area using a razor (detailed below).</li>
</ol>
2. Dissection of the Common Carotid Artery (CCA)
<ol>
	<li>Perform the entire microsurgery procedure under a stereomicroscope. Using surgical scissors and forceps perform a shallow midline incision in the neck, from above the breastbone to below the jaw (about 3 to 4 cm).</li>
	<li>Using forceps carefully separate fatty and connective tissue to expose the trachea.</li>
	<li>Place a pillow (round object, about 0.5 cm in diameter) on the back of the neck of the mouse to extend the neck, further exposing the area.</li>
	<li>Separate the tissue using either a tissue retractor or hooks.</li>
	<li>On the animal&#39;s left side of the trachea, carefully tweeze apart the connective tissue to expose the left CCA.</li>
	<li>Using forceps carefully remove all connective tissue to expose the CCA bifurcation, and the beginning of both external and internal carotid arteries.</li>
</ol>
3. Preparation of the CCA for Substance Infusion
<ol>
	<li>Insert two segments of nylon suture (about 1 cm each) under external carotid artery (ECA), using forceps.</li>
	<li>Place a permanent knot at the highest point possible of the ECA.</li>
	<li>At the lowest point possible of the ECA, immediately above the CCA bifurcation, place a removable knot. This knot should be loose compared to the upper knot.</li>
	<li>Close the CCA using a vessel clip, at the lowest possible point.</li>
	<li>Close the internal carotid artery (ICA) using a vessel clip.</li>
	<li>Using microdissection spring scissors perform a small cut in the ECA (about 2 mm), between the two knots.</li>
</ol>
4. Substance Infusion via ICA
<ol>
	<li>Assemble an infusion system. Attach 6 inches of capillary tubing (ideal dimensions: 2.5 mm x 1.2 mm) to a tuberculin syringe containing 250 &#181;l of the substance to be infused (drugs, pathogens, extracellular vesicles, among others) and insert the capillary tip gently into the incision performed in step 3.6.</li>
	<li>Continue to slide down the capillary until it reaches a midpoint between the bifurcation and the clip closing the CCA.</li>
	<li>Tie down the lower ECA knot. Verify that the knot is loose enough to allow capillary fluidity and tight enough to prevent leaking.</li>
	<li>Remove clip from the ICA.</li>
	<li>Gently apply pressure to the syringe piston allowing substance infusion at approximately 10 &#181;l per second.</li>
</ol>
5. Post Infusion Procedures
<ol>
	<li>Place clip back on the ICA.</li>
	<li>Gently remove the capillary tubing.</li>
	<li>Tie down the lower ECA knot completely.</li>
	<li>Remove clips from the ICA and the CCA.</li>
</ol>
6. Incision Closing and Post-operative Care
<ol>
	<li>Remove retractor or tissue hooks and pillow.</li>
	<li>Clean suture area using sterile saline.</li>
	<li>Close the incision using nylon suture/needle and forceps.</li>
	<li>Administer anti-inflammatory and analgesic to alleviate post-operative discomfort.</li>
	<li>Place animal in cage placed on heating pad for at least 1 hr and monitor recovery.</li>
</ol>

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	<li>Chen, L., Swartz, K. R., Toborek, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vessel+microport+technique+for+applications+in+cerebrovascular+research.">Vessel microport technique for applications in cerebrovascular research.</a> J Neurosci Res. 87 (7), 1718-1727 (2009).</li><li>Frisella, W. 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=Intracranial+injection+of+recombinant+adeno-associated+virus+improves+cognitive+function+in+a+murine+model+of+mucopolysaccharidosis+type+VII.">Intracranial injection of recombinant adeno-associated virus improves cognitive function in a murine model of mucopolysaccharidosis type VII.</a> Mol Ther. 3 (3), 351-358 (2001).</li><li>Wei, L., Erinjeri, J. P., Rovainen, C. M., Woolsey, T. 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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracarotid+delivery+of+oncolytic+HSV+vector+G47Delta+to+metastatic+breast+cancer+in+the+brain.">Intracarotid delivery of oncolytic HSV vector G47Delta to metastatic breast cancer in the brain.</a> Gene Ther. 12 (8), 647-654 (2005).</li><li>Kumar, P., 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=Transvascular+delivery+of+small+interfering+RNA+to+the+central+nervous+system.">Transvascular delivery of small interfering RNA to the central nervous system.</a> Nature. 448 (7149), 39-43 (2007).</li><li>Wrobel, J. K., Wolff, G., Xiao, R., Power, R. 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The authors have nothing to disclose.

The infusion microsurgery described here has been proved to be very successful in delivering exogenous substances of various biological features into the CNS, preventing unwanted dissemination throughout the body 1,12. Disruption of the blood-brain barrier is a pathological characteristic of several CNS-related diseases; therefore assessing the relationship of exogenous substances with the blood-brain barrier is of major importance and interest.
This surgery model presented causes limited trauma to the animals and is associated with very low mortality 1,12. Moreover, the procedure does not interfere with the CNS function or cerebral blood flow 1,12. The most critical aspect of this procedure is to perform the correct cut in the ECA, which should only allow the insertion of the capillary tubing. A wider cut will cause leaking of the substance to be infused, requiring another ECA surgery on the opposite site. In order to prevent this situation, the capillary tubing should have a bigger diameter than the cut, and should also have a sharp edge in order to facilitate its entrance through the artery. Regarding the technical aspect, a fully trained personnel is able to perform this surgery within 20 minutes.
The major limitation of this technique is the possibility of infusion only once through the same ICA. For repeated substance delivery into the CNS, a vessel microport needs to be used and has been described previously 1.The technique described here has the potential to assist in the studies on new positive and negative interactions within the BBB, as well as to deliver pathogens, drugs, and physiological agents into the brain.

In vivo models of central nervous system (CNS) diseases require an effective delivery of exogenous substances, such as drugs, pathogens, or exosomes, into the brain. Therefore, an ideal delivery method should cause minimal trauma to the animal, preserve the integrity of the neuronal network, and achieve high substance concentrations in the brain 1.
Several surgical methods of local substance delivery have been described, including intra-sheath, intracerebral, and intraventricular injections or implants 2,3,4,5. These approaches, however, are considered traumatic to the CNS, and allow administration of only low volumes of the substance of interest. Moreover, it has been suggested that exogenous substances can be rapidly removed by the cerebrospinal fluid 6, and a low penetration range to the brain parenchyma has been observed 7 when the above-mentioned techniques are employed. Systemic delivery methods, such as oral, pulmonary, subcutaneous, and intravenous routes, are more commonly used in animal models, though they exhibit low effectiveness in delivering the substances to the CNS, due to uptake by other organs 8,9. Therefore, these routes of delivery require elevated doses of the administrated substances, increasing the risk of side effects and toxicity 10,11.
Here, we describe a mouse infusion microsurgery technique, which effectively delivers substances directly into the brain via the internal carotid artery. In addition to targeting the delivery to the CNS, this technique does not bypass normal physiological barriers and is therefore highly relevant to biological processes involved in the passages of therapeutics or pathogens into the brain.

<table><tbody><tr><td>Anesthesia instrument</td><td>Vetequip</td><td>901806</td><td></td></tr><tr><td>Surgical scissors</td><td>Fine Science Tool</td><td>14558-09</td><td></td></tr><tr><td>Surgical forceps straight tip</td><td>Fine Science Tool</td><td>00108-11</td><td></td></tr><tr><td>Surgical forceps angled tip</td><td>Fine Science Tool</td><td>00109-11</td><td></td></tr><tr><td>Spring scissors</td><td>Fine Science Tool</td><td>15000-08</td><td></td></tr><tr><td>Nylon suture</td><td>Braintree Scientific</td><td>SUT-S 104</td><td></td></tr><tr><td>Capillary tubing (Micro-Renathane 0.010&amp;rdquo; x 0.005&amp;rdquo; per ft.)&amp;nbsp;</td><td>Braintree Scientific</td><td>MRE01050</td><td></td></tr><tr><td>Closing suture</td><td>VWR</td><td>95057-036</td><td></td></tr><tr><td>Isoflurane</td><td>Piramal</td><td></td><td></td></tr><tr><td>2,3,5-Triphenyltetrazolium chloride</td><td>FisherScientific</td><td>50-121-8005</td><td></td></tr></tbody></table>

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.

The mouse infusion microsurgery technique described here is very versatile and has been used to deliver different substances directly into the brain, including the delivery of tumor cells in a representative model of brain metastasis formation 1,12.
This technique is also suitable to assess the pathological aspects of different pathogens in the CNS. In a mouse model of HIV infection, the infusion surgery was used to inject viral particles directly into the CCA. We found that 7 days after surgery, the CNS was positive for HIV by real-time PCR. Furthermore, the ipsilateral hemisphere infection was 6-10 folds higher than the contralateral hemisphere (Figure 2).
Another suitable approach of the infusion surgery described here is to deliver extracellular vesicles (ECVs), mainly exosomes, into the CNS. Figure 3 shows the presence of CD63, a marker for exosomes, labeled with green fluorescent protein (GFP) in the ipsilateral brain of a mouse 24 hr after infusion.
<img alt="Figure 1" src="/files/ftp_upload/54804/54804fig1.jpg" /> 
Figure 1: Schematic Representation of the Infusion via the Internal Carotid Artery. In the insert (a) and (b) depict the localization of the upper and lower knots, respectively; (c) represents the small cut in the ECA, through which the capillary tubing is inserted (gray line). <a href="https://cloudflare-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54804/54804fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/54804/54804fig2.jpg" /> 
Figure 2: HIV Detection by Real-time PCR after Viral Infusion via the Internal Carotid Artery. Bars indicate mean HIV DNA levels harvested from mice 7 days post the infusion via the left internal carotid artery. Error bars depict standard deviation. <a href="https://cloudflare-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54804/54804fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/54804/54804fig3.jpg" /> 
Figure 3: Immunofluorescence of Mouse Brain Section Depicting GFP-tagged CD63, an Exosome Marker, after ECVs Infusion via the Internal Carotid Artery. The representative image depicts a mouse brain microvessel associated with CD63 expressing ECVs (green). Scale bar: 50 &#181;m. <a href="https://cloudflare-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54804/54804fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Mouse Microsurgery Infusion Technique for Targeted Substance Delivery into the CNS via the Internal Carotid Artery at JoVE.com

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.

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 ...

mouse-microsurgery-infusion-technique-for-targeted-substance-delivery

Universidad San Sebastian

Research

JoVE Journal

Neuroscience

10.8K Views.  University of Miami. The present protocol describes a mouse microsurgery infusion technique, which effectively delivers substances directly into the brain via the internal carotid artery.

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

Intracarotid Cancer Cell Injection to Produce Mouse Models of Brain Metastasis

Metastasis, the spread and growth of malignant cells at secondary sites within a patient&#39;s body, accounts for &#62; 90% of cancer-related mortality. Recently, impressive advances in novel therapies have dramatically prolonged survival and improved quality of life for many cancer patients. Sadly, incidence of brain metastatic recurrences is fast rising, and all current therapies are merely palliative. Hence, good experimental animal models are urgently needed to facilitate in-depth studies of the disease biology and to assess novel therapeutic regimens for preclinical evaluation. However, the standard in vivo metastasis assay via tail vein injection of cancer cells produces predominantly lung metastatic lesions; animals usually succumb to the lung tumor burden before any meaningful outgrowth of brain metastasis. Intracardiac injection of tumor cells produces metastatic lesions to multiple organ sites including the brain; however, the variability of tumor growth produced with this model is large, dampening its utility in evaluating therapeutic efficacy. To generate reliable and consistent animal models for brain metastasis study, here we describe a procedure for producing experimental brain metastasis in the house mouse (Mus musculus) via intracarotid injection of tumor cells. This approach allows one to produce large number of brain metastasis-bearing mice with similar growth and mortality characteristics, thus facilitating research efforts to study basic biological mechanisms and to assess novel therapeutic agents.

Brain metastasis has become an urgent unmet medical need as its incidence has increased while therapeutic options have remained palliative. Creating experimental animal models of brain metastasis via intracarotid arterial injection of cancer cells facilitates mechanistic studies of the disease biology and evaluation of novel intervention regimens.

Metastasis, the spread and growth of malignant cells at secondary sites within a patient&#39;s body, accounts for &#62; 90% of cancer-related mortality. ...

Cancer Research

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 ...

Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.

Sustained delivery of neuroactive agents is widely used in neuroscience, but poses many technical challenges. It is necessary to deliver the agent with high precision while minimizing localized trauma and inflammation. Also, the ability to customize the system to accommodate animals of different species and sizes is desirable. This video presentation demonstrates the construction of an infusion system that can be fitted to any particular research animal. The delivery microcannula diameter is approximately 10-fold smaller than most infusion cannulas presently used. This translates into enhanced accuracy and reduced trauma to the brain region under study. The delivery cannula can also be sculpted to fit the contour of the surface of the animal's skull, thereby allowing closure of the scalp incision neatly over the infusion system, precluding the need for a skull-mounted pedestal, reducing risk of infection, and ensuring a greater level of comfort to the animal. The system is assembled in an air-free environment and requires the researcher to fashion glass micropipettes with a heat source. These construction methods require special skills that are best acquired, if not in person, using video instruction.  (This article is based on work first reported in J Neurosci Methods. 2008 Jan 30;167(2):213-20. Epub 2007 Aug 28.).

As neuroscience inquiry becomes more sophisticated, investigation of brain structures and circuitry requires improved levels of accuracy and higher resolution. We have developed a method for the preparation and implantation of a chronic infusion system within the brain utilizing a borosilicate microcannula with a tip diameter of 50 microns.

Sustained delivery of neuroactive agents is widely used in neuroscience, but poses many technical challenges. It is necessary to deliver the agent with ...

Biology

Mouse Model of Intraluminal MCAO: Cerebral Infarct Evaluation by Cresyl Violet Staining

Stroke is the third cause of mortality and the leading cause of disability in the World. Ischemic stroke accounts for approximately 80% of all strokes. However, the thrombolytic tissue plasminogen activator (tPA) is the only treatment of acute ischemic stroke that exists. This led researchers to develop several ischemic stroke models in a variety of species. Two major types of rodent models have been developed: models of global cerebral ischemia or focal cerebral ischemia. To mimic ischemic stroke in patients, in whom approximately 80% thrombotic or embolic strokes occur in the territory of the middle cerebral artery (MCA), the intraluminal middle cerebral artery occlusion (MCAO) model is quite relevant for stroke studies. This model was first developed in rats by Koizumi et al. in 1986 1. Because of the ease of genetic manipulation in mice, these models have also been developed in this species 2-3.
	Herein, we present the transient MCA occlusion procedure in C57/Bl6 mice. Previous studies have reported that physical properties of the occluder such as tip diameter, length, shape, and flexibility are critical for the reproducibility of the infarct volume 4. Herein, a commercial silicon coated monofilaments (Doccol Corporation) have been used. Another great advantage is that this monofilament reduces the risk to induce subarachnoid hemorrhages. Using the Zeiss stereo-microscope Stemi 2000, the silicon coated monofilament was introduced into the internal carotid artery (ICA) via a cut in the external carotid artery (ECA) until the monofilament occludes the base of the MCA. Blood flow was restored 1 hour later by removal of the monofilament to mimic the restoration of blood flow after lysis of a thromboembolic clot in humans. The extent of cerebral infarct may be evaluated first by a neurologic score and by the measurement of the infarct volume. Ischemic mice were thus analyzed for their neurologic score at different post-reperfusion times. To evaluate the infarct volume, staining with 2,3,5-triphenyltetrazolium chloride (TTC) was usually performed. Herein, we used cresyl violet staining since it offers the opportunity to test many critical markers by immunohistochemistry. In this video, we report the MCAO procedure; neurological scores and the evaluation of the infarct volume by cresyl violet staining.

The intraluminal middle cerebral occlusion model in mice is herein presented. The extent of cerebral infarct is evaluated by a neurologic score and cresyl violet staining, an alternative staining to TTC, offering the great advantage to test in parallel many interest markers.

Stroke is the third  cause of mortality and the leading cause of disability in the World. Ischemic  stroke accounts for approximately 80% of all strokes. ...

Medicine

Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain barrier1. The barrier selectively excludes molecules from crossing between the blood and the brain based upon their size and charge. This function can impede the delivery of therapeutics for neurological disorders. A number of chemotherapeutic drugs, for example, will not effectively cross the blood-brain barrier to reach tumor cells2. Thus, improving the delivery of drugs across the blood-brain barrier is an area of interest.
The most prevalent methods for enhancing the delivery of drugs to the brain are direct cerebral infusion and blood-brain barrier disruption3. Direct intracerebral infusion guarantees that therapies reach the brain; however, this method has a limited ability to disperse the drug4. Blood-brain barrier disruption (BBBD) allows drugs to flow directly from the circulatory system into the brain and thus more effectively reach dispersed tumor cells. Three methods of barrier disruption include osmotic barrier disruption, pharmacological barrier disruption, and focused ultrasound with microbubbles. Osmotic disruption, pioneered by Neuwelt, uses a hypertonic solution of 25% mannitol that dehydrates the cells of the blood-brain barrier causing them to shrink and disrupt their tight junctions. Barrier disruption can also be accomplished pharmacologically with vasoactive compounds such as histamine5 and bradykinin6. This method, however, is selective primarily for the brain-tumor barrier7. Additionally, RMP-7, an analog of the peptide bradykinin, was found to be inferior when compared head-to-head with osmotic BBBD with 25% mannitol8. Another method, focused ultrasound (FUS) in conjunction with microbubble ultrasound contrast agents, has also been shown to reversibly open the blood-brain barrier9. In comparison to FUS, though, 25% mannitol has a longer history of safety in human patients that makes it a proven tool for translational research10-12.
In order to accomplish BBBD, mannitol must be delivered at a high rate directly into the brain's arterial circulation. In humans, an endovascular catheter is guided to the brain where rapid, direct flow can be accomplished. This protocol models human BBBD as closely as possible. Following a cut-down to the bifurcation of the common carotid artery, a catheter is inserted retrograde into the ECA and used to deliver mannitol directly into the internal carotid artery (ICA) circulation. Propofol and N2O anesthesia are used for their ability to maximize the effectiveness of barrier disruption13. If executed properly, this procedure has the ability to safely, effectively, and reversibly open the blood-brain barrier and improve the delivery of drugs that do not ordinarily reach the brain 8,13,14.

Blood-brain barrier disruption aids the delivery of certain drugs to the brain. Mannitol delivered intra-arterially shrinks cells surrounding blood vessels in order to physically disrupt the barrier.

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain ...

Modeling Brain Metastasis by Internal Carotid Artery Injection of Cancer Cells

Brain metastasis is a cause of severe morbidity and mortality in cancer patients. Critical aspects of metastatic diseases, such as the complex neural microenvironment and stromal cell interaction, cannot be entirely replicated with in vitro assays; thus, animal models are critical for investigating and understanding the effects of therapeutic intervention. However, most brain tumor xenografting methods do not produce brain metastases consistently in terms of the time frame and tumor burden. Brain metastasis models generated by intracardiac injection of cancer cells can result in unintended extracranial tumor burden and lead to non-brain metastatic morbidity and mortality. Although intracranial injection of cancer cells can limit extracranial tumor formation, it has several caveats, such as the injected cells frequently form a singular tumor mass at the injection site, high leptomeningeal involvement, and damage to brain vasculature during needle penetration. This protocol describes a mouse model of brain metastasis generated by internal carotid artery injection. This method produces intracranial tumors consistently without the involvement of other organs, enabling the evaluation of therapeutic agents for brain metastasis.

Brain metastasis is a cause of severe morbidity and mortality in cancer patients. Most brain metastasis mouse models are complicated by systemic metastases confounding analysis of mortality and therapeutic intervention outcomes. Presented here is a protocol for internal carotid injection of cancer cells that produces consistent intracranial tumors with minimal systemic tumors.

Brain metastasis is a cause of severe morbidity and mortality in cancer patients. Critical aspects of metastatic diseases, such as the complex neural ...

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.

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 ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Common Carotid Artery Repair After Injection in a Mouse Model 

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there is an urgent need to develop methods for intracarotid injections in mouse models, including methods to repair the carotid artery in mice after injection to allow for subsequent injections. We developed a method of intracarotid injection in a mouse model to deliver therapeutics into the internal carotid artery (ICA) with two alternative procedures. 
During injection, the needle is inserted into the common carotid artery (CCA) after tying a suture around the external carotid artery (ECA) and injected therapeutics are delivered into the ICA. Following injection, the common carotid artery (CCA) can be ligated, which limits the number of intracarotid injections to one. The alternative procedure described in this article includes a modification where intracarotid artery injection is followed by injection site repair of the CCA, which restores blood flow within the CCA and avoids the complication of cerebral ischemia seen in some mouse models. 
We also compared the delivery of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) to intracranial tumors when delivered through intracarotid injection with and without injection site repair following the injection. Delivery of BM-hMSCs does not differ significantly between the methods. Our results demonstrate that injection site repair of the CCA allows for repeat injections through the same artery and does not impair the delivery and distribution of injected material, thus providing a model with greater flexibility that more closely emulates intracarotid injection in humans.

Author Spotlight: Advancing Glioblastoma Treatment Through Intraarterial Delivery Strategies for Oncolytic Viruses and MicroRNAs

Repair of the intracarotid artery in a mouse model after injection returns blood flow to the artery without negatively impacting the distribution of the injected material. Injection site repair facilitates subsequent injections through the same artery and prevents cerebral ischemia in mouse strains that lack a complete Circle of Willis.

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there ...

Intra-Arterial Delivery of Neural Stem Cells to the Rat and Mouse Brain: Application to Cerebral Ischemia

Neural stem cell (NSC) therapy is an emerging innovative treatment for stroke, traumatic brain injury and neurodegenerative disorders. As compared to intracranial delivery, intra-arterial administration of NSCs is less invasive and produces a more diffuse distribution of NSCs within the brain parenchyma. Further, intra-arterial delivery allows the first-pass effect in the brain circulation, lessening the potential for trapping of cells in peripheral organs, such as liver and spleen, a complication associated with peripheral injections. Here, we detail the methodology, in both mice and rats, for delivery of NSCs through the common carotid artery (mouse) or external carotid artery (rat) to the ipsilateral hemisphere after an ischemic stroke. Using GFP-labeled NSCs, we illustrate the widespread distribution achieved throughout the rodent ipsilateral hemisphere at 1 d, 1 week and 4 weeks after postischemic delivery, with a higher density in or near the ischemic injury site. In addition to long-term survival, we show evidence of differentiation of GFP-labeled cells at 4 weeks. The intra-arterial delivery approach described here for NSCs can also be used for administration of therapeutic compounds, and thus has broad applicability to varied CNS injury and disease models across multiple species.

A method for delivering neural stem cells, adaptable for injecting solutions or suspensions, through the common carotid artery (mouse) or external carotid artery (rat) after ischemic stroke is reported. Injected cells are distributed broadly throughout the brain parenchyma and can be detected up to 30 d after delivery.

Neural stem cell (NSC) therapy is an emerging innovative treatment for stroke, traumatic brain injury and neurodegenerative disorders. As compared to ...

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

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Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.

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Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

Modeling Brain Metastasis by Internal Carotid Artery Injection of Cancer Cells

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

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique

Intra-Arterial Delivery of Neural Stem Cells to the Rat and Mouse Brain: Application to Cerebral Ischemia