Fatty Foam

Deep inside a rabbit’s lung, something bad is happening. The red region is caseum – a cheese-like collection of dead and dying cells caused by infection with Mycobacterium tuberculosis bacteria, which cause the serious lung disease tuberculosis. Also packed into the caseum are fat-filled immune cells known as foam cells – it’s the fat droplets inside them that are picked up by the red dye used to stain this sample. Foam cells are also found in the fatty artery-blocking plaques in heart and cardiovascular disease, where they’re packed with the ‘bad’ cholesterol that’s linked to heart disease. But the foam cells in tuberculosis-infected lungs appear to be packed with a different type of fat altogether, known as triglycerides. The discovery points to completely different biological pathways at work in the two diseases, suggesting that stopping triglyceride manufacture in these foam cells could lead to entirely new ways to treat tuberculosis.

Written by Kat Arney

Kat Arney

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Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image from work by Valentina Guerrini and colleagues
• Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
• Image originally published under a Creative Commons Licence (BY 4.0)
• Published in PLOS Pathogens, August 2018