Ultra-thin fibres designed to protect nerves after brain surgery
HALLE (SAALE), Germany: Pharmacists at Martin Luther University Halle-Wittenberg (MLU), in cooperation with neurosurgeons at university hospital Halle (Saale), have developed a new method that allows direct application of the drug nimodipine in the brain with fewer side effects. The drug may prevent nerve cells from dying after brain surgery.
Brain surgery poses a major threat to nerve cells because even slight injuries can kill the sensitive cells. The drug nimodipine, which is currently being used to treat cerebral haemorrhages, might help prevent this. The drug relaxes blood vessels which can prevent cramping and it also appears to stop nerve cells from dying. The research group led by Prof. Karsten Mäder from the institute of pharmacy at MLU has now developed a system that enables the drug to be applied directly in the brain. “The neurosurgeons wanted the drug to be applied locally in order to reduce potential side effects,” said Mäder.
His research group has integrated nimodipine into biodegradable polymer fibres. The fibres are only 1 to 2 μm thick and degrade in the body. The material used to produce them is already widely used in medicine. “If you want to apply something directly to the nerves, it must be well tolerated,” explained Mäder. This is because nerve cells are particularly sensitive. So far, the nimodipine-polymer fibres have been tested in the laboratory for stability and their effect on different cell cultures. The research team has been able to show that the fibres release the active ingredient at a very constant rate. This is important as it prevents side effects in the case of an overdose.
Directly applying it to the brain could minimise these side effects because significantly less of the active ingredient is required
Following this, Prof. Christian Scheller’s research group from the department of neurosurgery at the university hospital tested how the fibres affected various brain cells. The fibres showed no toxic effects. Under various stress conditions, such as heat or high salt concentrations, they partly reduced the number of cell deaths. Nerve cells particularly benefited from the treatment.
“In the cell systems, we were able to show that the effect was as good as if we had added the active ingredient without the fibres, in other words intravenously,” said Scheller. However, the latter method has several disadvantages. The active ingredient degrades very quickly and has undesirable side effects, as it relaxes the blood vessels not only in the brain but throughout the entire body including the heart muscles. The result of a high dose can therefore be dangerously low blood pressure. Directly applying it to the brain could minimise these side effects because significantly less of the active ingredient is required. The fibres could also be used outside the brain, according to Scheller, for example in different types of operations where nerves are at risk.
The study, titled “Electrospun nimodipine-loaded fibers for nerve regeneration: Development and in vitro performance” was published in the June 2020 issue of the European Journal of Pharmaceutics and Biopharmaceutics.