Why is internal carotid artery targeting important for brain metastasis modeling?

Targeting the internal carotid artery ensures directed delivery of cancer cells to the brain, as it supplies cerebral blood flow. This increases the likelihood of successful tumor engraftment in the brain parenchyma. It improves model reliability by reducing off-target cell distribution to extracranial tissues.

How does suturing the external carotid artery improve injection specificity?

Suturing the external carotid artery prevents retrograde flow and redirects injected cancer cells toward the internal carotid artery. This enhances the proportion of cells reaching the brain vasculature. It increases the efficiency and specificity of brain metastasis induction.

What quantitative measurements enable assessment of tumor development over time?

Tumor incidence, volume, and latency are key metrics used to evaluate metastatic progression in the brain. These can be measured via imaging, bioluminescence, or histopathological analysis. Longitudinal tracking supports dose-response and therapeutic efficacy assessments.

Why are replication requirements critical for cross-functional collaboration in metastasis studies?

Replication ensures that observed metastatic phenotypes are consistent and not due to surgical variability or biological noise. It builds confidence in target validation and therapeutic screening results across teams. Standardized replication supports data comparability in multi-site preclinical programs.

What statistical analysis capabilities are required before implementing this model in drug discovery?

Power analysis is needed to determine appropriate group sizes for detecting differences in tumor burden or survival. Parametric or non-parametric tests are used to compare treatment groups based on data distribution. Correcting for multiple comparisons ensures valid interpretation of screening or efficacy outcomes.

Modeling Brain Tumor Metastasis via Internal Carotid Artery Injection of Cancer Cells

JoVE Encyclopedia of Experiments

Neuroscience

0 views • 3:42 min • April 28th, 2025

$$\rightleftharpoonup{xx}$$ $$\longleftharp{xx}$$, $$\longrightharp{xx}$$,

Begin with an anesthetized mouse with an exposed common carotid artery or CCA.

The CCA bifurcates into the external carotid artery, or ECA, supplying blood to the face, and the internal carotid artery, or ICA, supplying blood to the brain.

First, place a suture around the ECA and tighten it.

Then, add a tight suture on the CCA below the injection site to block blood flow.

Insert a moist paper strip under the CCA for support.

Place a loose knot above the injection site, then inject cancer cells into the CCA.

Due to the sutured ECA, the cells travel to the ICA to reach the brain.

After injection, remove the needle and tighten the distal knot of the CCA to prevent backflow.

Finally, Trim the sutures, remove the strip, rinse with saline, and close the wound.

Over time, the migrated cancer cells propagate and develop tumors in the brain.

Position fine forceps under the external carotid artery and pass a 5-0 silk suture under the artery. Knot and tighten the suture and cut excess line. Position fine forceps under the common carotid artery and pass a 5-0 silk suture under the artery.

Tie a knot and tighten the suture at a position proximal to the proposed injection site. Cut the excess suture, leaving about 10 millimeter of the line. Cut and moisten a strip of low lint disposable wipers about 10 by 5 millimeters.

Fold the strip and place it underneath the carotid artery at the proposed site of injection. This will support the vessel during the injection. On the common carotid artery rostral to the proposed injection site, place a third ligation with a loose knot. This is tightened only after the injection.

Gently agitate the cell suspension and draw 200 microliters of cell suspension into an insulin syringe with a 31 gauge needle. Load the syringe into the syringe driver connected to an activating foot pedal.

Attach a fine cannula with a 31 gauge needle to the syringe and prime the line. Check whether the carotid artery is well positioned and pressurized. Using two fine angled forceps, one gently tensioning onto the end of the first ligature and the other holding the 31 gauge needle, slowly insert the needle with the bevel up into the lumen of the blood vessel, taking care not to puncture it.

Slowly inject 100 microliters of cell suspension prepared earlier into the common carotid artery at 10 microliters per second. This will deliver 2.5 times 10 to the fifth cells into the blood vessel. Successful injection can be visualized via the clearing of blood from the carotid blood vessel.

Gently lift and tighten the loose ligature immediately after withdrawing the needle to prevent backflow and bleeding. Trim excess sutures and remove the piece of moistened, low lint disposable wipers.

Using a P200 pipette, rinse the surgical cavity twice with 150 to 200 microliters of sterile water or saline. After checking for bleeds, reposition the soft tissue, salivary glands, and skin over the carotid artery and trachea. Close the skin layer of the incision using a suture needle holder, forceps, and an absorbable or non-absorbable 6-0 monofilament suture in a continuous pattern.