Gene therapy. Using viral vectors is one of the most promising approaches for treating cardiac diseases. The procedures we're creating an ischemic heart failure model, as well as gene delivery by viral vector are presented in this video.
The first step is creating a myocardial infarct in a swine model. To do this, a coronary wire is proceeded into the coronary artery, followed by an occlusion balloon. Using endovascular accent, the balloon will be inflated to completely occlude the coronary artery.
As a result, a large infarct is created in the anterior area, and the pigs will develop chronic heart failure. The next step is the virus injection. Viral vectors are slowly injected into the coronary artery.
It will be carried by the bloodstream and distributed into the myocardium. The virus will get into the cardiomyocytes, then into the nucleus, and send signals to create proteins. The expressed proteins will fortify cardiac performance and increase the overall function.
In this video, we represent procedures for gene therapy for ischemic heart failure using a swine model. First, we will show how to create a myocardial in production in a peak, and then we will go on to demonstrate the inter coronary delivery of a viral vector. We use this procedure to test efficacy and the safety of various gene transfers.
So let's get started. To begin the procedure, anesthesia is induced in the pig using telazol. Established an intravenous line in the ear vein, then intubate the pig.
Place the pig in a dorsal recumbent. Use propofol for general anesthesia during the experiment. To maintain the blood pressure, clean the groin area with alcohol followed by iodine.
Cover the site with a sterile sheet and prepare everything sterile. Puncture the femoral artery with an 18 gauge needle using the Seldinger method. When you see pulsive backflow, insert the wire, then place the sheath after sheath insertion, inject heparin to prevent thrombus formation during the experiment.
Next, prepare a saline bag with 75 milligrams of amiodarone, 20 milliequivalents of potassium, and 20 milligrams of atropine, and use a rate of 150 milliliters per hour. An intramuscular injection of 75 milligrams of amiodarone is given at this time. Proceed the guiding catheter into the left coronary artery osteo, and take an angiogram to check the coronary anatomies.
Insert the wire carefully into the left anterior descending coronary artery. Then proceed the balloon over the wire into the coronary artery. Take an angiogram to make sure of the position of the balloon.
Another angiogram should be taken from a different angle to check the position of the balloon. Then gradually inflate the balloon to three ATM. Take another angiogram to confirm the occlusion of the artery.
Monitor the pig with both arterial pressure and electrocardiography. Occasionally the pig will go into ventricular fibrillation. Defibrillate the pig with direct current shock as soon as possible.
If the attempt fails, compress the chest until the cardioverter chargers and administer another shock. Observe for 90 minutes and deflate the balloon. Once blood pressure and the arrhythmia have stabilized, remove the sheath and recover the pig.
Give an intramuscular injection of nitroglycerin and furosemide as well as an overnight fluids containing amiodarone. Prepare yourself in a cap mask, goggles, gown, and gloves. The pig is prepared in the same manner as the myocardial infarct creation.
Insert one coronary wire each into the left interior descending coronary artery and the left circumflex coronary artery. Place a catheter at the osteum. Draw 20 milliliters of arterial blood using 10 milliliters for the virus injection and the rest for flush.
Mix the virus with 10 milliliters of blood and dilute it to 20 milliliters with saline. Then dilute the remaining blood with saline to 20 milliliters and divide it into two syringes. Connect the syringe containing blood, mixed with the virus to the catheter, and prepare for the infusion.
An intravenous injection of 20 micrograms per minute of nitroglycerin is started through the ear vein, taking the angiogram to check the position of the catheter. Then start the virus injection with a rate of one milliliter per minute when 15 milliliters have been injected into the left coronary artery. Change the syringe for the flush and use the same injection rate After the injection to the left coronary artery, the same procedure will be performed to the right coronary artery using the remaining five milliliters of blood containing the virus.
One month after the myocardial infarct creation, the P will develop heart failure with an impaired wall motion and a dilated heart. The average ejection fraction at one month after the myocardial infarct in this model is 36%and is significantly lower than pigs of the same size without a myocardial infarct. The average end diastolic volume is 83 milliliters, whereas the average of a control is 42 milliliters.
DP DT was also significantly lower in the myocardial infarct pigs. These are the cross sections of the left ventricle. At one month after the myocardial infarct, a large scar from the base of the apex of the interior wall is found.
This picture shows the gale expression. One month after gene transfer using a dental associated virus, a significant expression was found in the virus injected area. We have just shown you how to create a myocardial effect in a pig as well as corona virus injection.
This combination of is I failure model and gene delivery is a simple and reproducible method to test various types of gene therapies in trajectory disease. Thank you for watching and with us with your future experie P.
