Above: A cellulose membrane for protecting pacemakers. Image credit: Hylomorph
By Anthony Caggiano
A cellulose membrane that can reduce the buildup of fibrotic tissue around cardiac pacemakers has been developed by ETH Zurich, Switzerland, scientists.
It could be used to help ease surgery when a pacemaker needs to be replaced.
Aldo Ferrari, a Senior Scientist in ETH Professor Dimos Poulikakos’s group and at research institute Empa, said if too much tissue has grown around a pacemaker – which usually has a lifespan of five years when its battery expires – it can be hard to remove the device in surgery. The surgeon may need to spend time cutting the tissue, and risk of infection may increase.
Ferrari and his colleagues at ETH Zurich have developed a membrane with a special surface structure that is less conducive to the growth of fibrotic tissue than the smooth metal surface of pacemakers.
This membrane has now been patented and Ferrari is working with fellow researchers at the Wyss Zurich research center, the University of Zurich and the German Center of Cardiovascular Research in Berlin to make it market-ready for use in patients.
To test the device, pigs were given two pacemakers - one enveloped in the cellulose membrane, one without. After a year of testing, the researchers found the pigs’ bodies did not reject the cellulose membrane.
‘This is an important finding because tolerance is a core requirement for implant materials,’ Ferrari said.
The fibrotic tissue that formed around the membrane was about a third of what grew around the unencapsulated pacemakers.
Two reasons have been identified as to why this may have happened. The first is because the material is fibrous by nature. Francesco Robotti, lead author of the study and a scientist in Professor Poulikakos’s group, explained further.
'When fibrotic tissue forms, the first stage is the deposition of proteins on the surface. A fibrous membrane surface impedes this process,’ he said.
The second factor is the researchers created the membrane with honeycomb-like indentations in the surface, each measuring 10 micrometres in diameter.
'These indentations make it difficult for the cells that form fibrotic tissue to adhere to the surface - the second stage in the formation processes,’ Robotti said.
The scientists want to apply for approval for clinical trials in humans in partnership with ETH spin-off Hylomorph, which will be responsible for commercialising the membrane. The trials are slated to start next year at three cardiac centres in Germany.
