Using parasites to treat disease

By modifying different parasites, researchers have found separate ways to deliver drugs to the brain and develop a more effective vaccine against malaria.

A study led by the University of Glasgow, UK, and Tel Aviv University, Israel, looked to the common parasite Toxoplasma gondii, which is carried by around a third of the global population but only reproduces in the guts of cats. It can travel to the brain by crossing the blood-brain barrier – a layer of cells that usually prevents harmful agents such as pathogens and toxins from entering the brain.

The team made use of T. gondii’s ability to infect the brain (it can release proteins into the neurons) to instead deliver therapeutic proteins to help treat neurological diseases.

When a modified version of T. gondii was injected into both mice and brain organoids, it successfully delivered a protein, MeCP2, which is a promising target for treating the rare developmental disorder Rett syndrome.

This approach could work for any disease that is caused by an abnormal or deficient protein, according to the team, and could “generate a golden opportunity for solving the great therapeutic challenge of delivering medications to the brain”, said Prof. Lilach Sheiner, at Glasgow – see also the video.

Meanwhile, another study led by Heidelberg University Hospital, Germany, genetically modified the parasite that causes malaria to develop at much slower rate in mice than in mosquitoes, which spread the disease.

This allowed the mice to fight off infection from the parasite, and their immune systems could then develop immunity that protected them against future infections.

The research could lead to the development of more reliable malaria vaccines, which are currently not as effective against severe infection, or are too expensive.