Brain Gain

Brain organoids like the one pictured (with neural progenitors (coloured red) and neurons (cyan)) were recently used to screen an assortment of drugs to find candidates for treating a rare, usually fatal, childhood mitochondrial disease called Leigh syndrome – characterised by defective energy production, epileptic seizures, mental impairment, muscular weakness and paralysis. Surprisingly, the screen revealed sildenafil, better known by its commercial name Viagra, as capable of improving growth and electrical functioning of nerve cells in the organoids. The drug also extended the lifespan of Leigh syndrome model mice. Based on these results and the drug’s known safety, it was given to a small number of Leigh syndrome patients in whom it improved symptoms. The reason for sildenafil’s seemingly disparate clinical benefits might come down to its activation of a multifunctional cell signalling molecule. Whatever the case, the drug’s potential for treating such a devastating childhood disease is welcome news.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image from work by Annika Zink, Dao-Fu Dai and Annika Wittich and colleagues, Alessandro Prigione lab
• Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-Düsseldorf, Düsseldorf, Germany
• Copyright held by HHU Stephanie Le, AG Prigione
• Research published in Cell, March 2026