Scientists from USA have developed a method to produce a ready made supply of blood vessels for use in heart bypass surgery. A study on baboons and dogs reported in journal Science Translational Medicine suggests vessels could be stored for up to a year and used by any patient. These vessels have been grown earlier from a patient’s own cells, but this takes several months.
Heart bypass operation is necessary in coronary heart disease where there is narrowing or blocking of arteries which bring oxygen to the heart muscle. Every year 28,000 coronary artery bypasses are performed, where blood vessels from other parts of the body are taken and used to “bypass” the blockage. It is not always possible to use the patient’s own blood vessels and several research groups are trying to create artificial ones.
But now researchers, at the biotech firm Humacyte, the Brody School of Medicine at East Carolina University and Duke University Medical Centre in North Carolina, built an artificial tube-shaped scaffold and added human smooth muscle cells. As the cells grow they build their own scaffolding out of collagen, and the original structure breaks down to create a blood vessel with the person’s cells. The researchers then used detergent to kill off the cells so the remaining collagen tube could be implanted in anyone without triggering an immune reaction. The tubes can be stored for at least 12 months and when used in baboons they were still allowing the blood to flow normally after a six month trial.
Researchers said, “Patients have no waiting period for graft production because the grafts have already been created and stored as opposed to custom made grafts for each patient that involve a lengthy waiting time.” Dr Alan Kypson, of the Brody School of Medicine at East Carolina University who was involved in the experiment, said, “This new type of bioengineered vein allows them to be easily stored in hospitals so they are readily available to surgeons at time of need…Currently, grafting using the patient’s own veins remains the gold standard. But harvesting a vein from the patient’s leg can lead to complications, and for patients who don’t have suitable veins the bioengineered veins could serve as an important new way to provide a coronary bypass.”
Professor Laura Niklason, cofounder of Humacyte said, “I think it really takes regenerative medicine to the next level… Normally you have to take cells and grow a tissue for one patient at a time, now we can do it on a mass scale, it’s a game changer.”
Professor John Hunt, UK centre for tissue engineering also enthused over the findings saying, “It’s very exciting you just have to address the safety issues… It’s a big leap from producing cell-based products for healthy animals for a short time to producing them for unhealthy humans for a lifetime. How do you ensure it lasts for 10 to 15 years, which would be a major advance?”
Professor Jeremy Pearson, associate medical director at the British Heart Foundation added, “Not everyone is well enough to have a vein taken from another part of their body during heart surgery, so using synthetic veins can become an important part of a patient's treatment. However, sometimes even synthetic veins aren’t suitable…This study shows that bioengineering can be used to create a novel type of vascular graft that has the potential to improve outcomes for patients. We look forward to the results of clinical trials designed to test this.”
Professor Niklason continued, “It can be used for skin, ligaments, cartilage or other simple tissues where it is really the structure, not the cells, which provide the function.” The researchers hope to begin human trials on artificial blood vessels next year.
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