Stuttgart, Germany - A new protein coating for respiratory stents, developed by Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, is designed to enhance incorporation of respiratory stents into the surrounding tracheal tissue, and also to lower the risk of infection for patients.
As with coronary stents, similar implants are used to treat pathological constriction of the windpipe. This condition, called respiratory stenosis, may be caused by tumours, chronic infections or congenital deformities, and can be life-threatening, says the IGB. Complications can arise when the implants are inserted, if bacteria colonise the stents and trigger pneumonia.
"The windpipe has an important barrier function, with goblet and cilia cells purifying the inhaled air. It is very important that cells like these can adhere to the stents so as to maintain the air-purifying effect of the damaged section of the windpipe and to promote incorporation of the stents in the surrounding tracheal tissue," said Dr Martina Hampel, a scientist at Fraunhofer IGB in Stuttgart, in a statement.
Together with Prof Thorsten Walles, head of the department of thoracic surgery at the University Hospital of Würzburg and a visiting IGB scientist, Hampel and her team took part in a project to develop surface coatings that enable the stents to be incorporated in the surrounding tissue, also reducing the risk that they will move and block the trachea
The scientists used stents lined with a polyurethane (PU) film, produced by Aachen-based Leufen Medical GmbH. They tested a wide variety of coatings for the PU film, including synthetic polymers composed of organic acids, biological proteins such as fibronectin and type-I collagen, some plasma-modified before use.
The protein-coated film showed the best results with primary tracheal epithelial cells growing particularly well and multiplying. "The respiratory cells proved to be more vital on bioactive films rather than on ones treated with plasma. … polymer-coated film turned out to be completely useless," said Hampel.
Next animal tests will be conducted, potentially followed by clinical trials at the Schillerhöhe specialist lung clinic. "We hope that, within just a few years, our well-tolerated, cell-compatible surface coatings will be used for other biomedical prostheses such as pacemaker leads, tooth implants and replacement joints," commented Hampel.