New Coating for Vascular Grafts Dissolves Blood Clots

A novel thrombolytic coating for vascular grafts could obviate the need for continuous use of anticoagulants, according to a new study.

Researchers at ITMO University (St. Petersburg, Russia) and Petrozavodsk State University (Russia) have developed a new family of injectable composites for treating thrombolysism composed of urokinase plasminogen activator entrapped within alumina. The thrombolytic coating is a sol-gel made of nanocrystalline oxides, and can thus lock the necessary thrombolytic enzymes inside the polymer vascular graft, making the productive lifespan of the graft virtually limitless.

The nanoarchitecture of the sol-gel thrombolytic coating is also bio-inert, ensuring near perfect stability. According to the researchers, the alumina, which serves as the urokinase plasminogen activator carrier, helps to prolong its activity in vivo and reduce the total administered dose of anticoagulant drugs necessary following a stent graft procedure, and hence the eventual side effects, such as the danger of hemorrhagic stroke. The study was published on August 13, 2015, in the Journal of Medicinal Chemistry.

“Modern vascular grafts are medicated and they emit the drug into the bloodstream; however, the concentration of the medication in the graft decreases with time and then clots may reappear. This coating provides unhampered bloodstream preventing thrombosis,” said lead author Yulia Chapurina, MSc, of the ITMO laboratory of solution chemistry of advanced materials and technologies. “The new technology is based on drug entrapping. It means that the protective coating holds it inside the vascular graft.”

The sol-gel process is a method for producing solid materials from small molecules, and is used for the fabrication of metal oxides, especially the oxides of silicon and titanium. In the procedure, the 'sol' (solution) gradually evolves towards the formation of a gel-like diphasic system containing both a liquid phase and solid phase whose morphologies range from discrete particles to continuous polymer networks. The unique properties of the sol-gel provide the possibility of their use for a variety of medical applications.

Related Links:
ITMO University
Petrozavodsk State University