Aorta made of polylactic acid

Rats were implanted with an artificial vessel

Anton Kurbatov, Indicator

Scientists from Peter the Great St. Petersburg Polytechnic University, I.P. Pavlov First St. Petersburg State Medical University and the Institute of High Molecular Compounds of the Russian Academy of Sciences have developed a matrix that can be used as a vascular implant. They implanted it into the abdominal aorta of laboratory rats and monitored it for 16 months. During this time, an artificial vessel was formed in place of the matrix, very similar to the real one. This brings scientists closer to the development of vascular implants for humans.

Article by Popov et al. A Morphological Study of a Bioresorbable Tubular Matrix of a Small Diameter from a Poly (L-lactide) for a Tissue-Engineered Vascular Implant is published in the journal Cell and Tissue Biology.

Synthetic prostheses, traditionally used in cardiovascular surgery, are well suited for the reconstruction of large vessels with a diameter of more than five millimeters. However, they are absolutely inapplicable when it comes to vessels of smaller diameter, since proteins that are contained in the blood fall out on the inner walls. And together with the low blood flow rate, this leads to the formation of blood clots in the patient. "It is impractical to use a synthetic prosthesis in pediatric cardiac surgery, because the prosthesis does not grow with the child — it is necessary to perform repeated operations. These are the reasons why it is necessary to develop technologies for creating artificial vessels," explained Vladimir Yudin, one of the researchers, head of the Research Laboratory (NIL) "Polymer Materials for Tissue Engineering and Transplantology" of SPbPU.

Scientists have made a synthetic matrix from polylactic acid. It is a biodegradable polymer that is contained in the human body. Once in the right place, the matrix dissolves, and a vessel appears in its place. "The matrix itself consists of nano- and microfibers, which are very similar to the fibrous structure of a natural vessel. Donor cells grow well on such a matrix. We have studied its properties — mechanical strength, porosity, hydrophobicity," said Pavel Popryadukhin, an employee of the Research Institute "Polymer Materials for Tissue Engineering and Transplantology" of SPbPU.

To test their invention, scientists conducted experiments on animals. They sewed a matrix into the abdominal aorta of laboratory rats. After that, the researchers observed the animals. They found out that in the intermediate stages, the artificial vessel was very similar to the real one. And 16 months after implantation, the matrix completely dissolved. But at the end of the study, the scientists found an expansion of the vessel in the rats in the place where they carried out the reconstruction. According to scientists, in order to prevent the development of such complications, it is necessary to develop a method of additional strengthening of the matrix wall. To do this, they plan to insert the matrix into the cells of the middle layer of the vessel, which is responsible for strength.

"At the same time, we have made many positive conclusions. In long experiments, the safety of the matrix was demonstrated. We have shown the very possibility of the formation of new tissues in it. It was proved that the matrix is non-toxic and has high patency: the total patency of the implants was 93%. This is a high indicator, which indicates that while a new vessel is being formed, the matrix will be passable," said Guriy Popov, the lead author of the work, a cardiovascular surgeon at PSPbSMU.

Portal "Eternal youth" http://vechnayamolodost.ru