Precision Ultrasound-guided Stem Cell Delivery for Vascular Repair in Aortic Diseases

Our study focus on the vascular stem cells in aortic aneurysm or dissection, investigating their role in disease progression, and evaluating their therapeutic potential for the treatment of vascular diseases.

Tissue-specific injection and intravenous infusion are common. But our ultrasound-guided memory injection technique overcomes challenges in aortic or , the one stem cell research.

This technique is minimally invasive, easy to perform, and does not require major surgeries, like thoracotomy or laparotomy, reducing complications and the recovery time.

This technique localize the stem cell therapy, offering a new approach for treating vascular diseases, and open possibilities for targeted regenerative treatments.

[Automated Voice] To begin, add 0.05% trypsin to vascular stem cells one hour before injection. Use a hemocytometer to count the cells. Then centrifuge the cell suspension at 200 g for five minutes at room temperature before removing the supernatant. Re-suspend the cell pellet in Matrigel that has been pre-thawed at four degrees Celsius. Gently mix the mixture by pipetting, and place it on ice until injection. Next, position an anesthetized mouse dorsally on a heated platform at 37 degrees Celsius to expose the abdomen. Apply conductive gel to each of the four platform electrodes. Then use medical tape to secure the mouse's paws to the electrodes for physiological monitoring. Using a sterile cotton swab, apply depilatory cream to the intended injection area. After a minute, gently wipe the area clean with a new swab. Drape the surgical site. Aseptically prepare a sterile syringe and maintain a sterile field throughout the procedure. For ultrasound-guided injection, first adjust the ultrasound platform to an angle of 30 degrees relative to the floor. Have the operator face the animal's right side, with the animal's head to the left. Then apply ultrasound gel to the cleaned and disinfected area. Position the ultrasound probe on the right side of the sternum to visualize the long axis of the aortic arch. Load 25 microliters of the vascular stem cell suspension into a 29-gauge needle, and wipe the needle tip with sterile alcohol. Secure the syringe onto the ultrasound-guided injection apparatus, ensuring the needle is aligned with the probe and angled 45 degrees relative to the chest wall. Now slowly move the injection needle into the ultrasound field of view. Align it to the focal plane, and match it with the guiding line on the screen. As the needle nears the skin edge, use blunt forceps to lift the skin and abdominal wall, then rapidly insert the needle through the chest wall. Under ultrasound guidance, guide the needle to the outer membrane between the innominate artery and the aortic arch. Gently lift and lower the syringe to confirm the correct position. Press the syringe to inject the cell suspension into the designated area. Slowly withdraw the needle, and disinfect the puncture site using standard post-injection protocol. mCherry labeled vascular stem cells remained in the aortic wall four weeks after injection, and migrated from the adventitial layer toward the media and intima of the vessel wall. Ultrasound imaging revealed a visible reduction in ascending aorta diameter in stem-cell-treated mice after four weeks, compared to untreated controls. Quantitative analysis confirmed that the increase in ascending aorta diameter was significantly lower in the treated group, compared to untreated mice.