CFS and C. elegans – advances in the understanding of chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a disease that affects 500,000 people in the UK. Currently, there is no definitive list of symptoms and no tests available for diagnosis – in fact, there is much debate over its cause, treatment, and even existence. Possible causes of CFS have ranged from viruses to parasites, genetic traits to environmental influences, but little research has come to fruition until now.

Potential new ways to diagnose CFS

Naviaux et al from the University of California conducted experiments investigating the metabolome- the cellular metabolic pathways and products-  of 45 patients with CFS, and 39 without. These researchers looked at 612 metabolic proteins from 63 pathways, and found there is a distinct metabolic state in people with CFS. Patients showed differences in 20 metabolic pathways, 80% of which showed a decrease in metabolic activity (hypometabolism). Some of the hypometabolic pathways included sphingolipid, phospholipid, and cholesterol metabolism. This decrease was so pronounced that the researchers could identify people who suffer from CFS with over 90% accuracy, when presented with just the readout of their metabolome.

What causes this metabolic change? 

Even more unusually, there are links between CFS and ‘dauer’ –   a state found in animals, including the model organism worm C. elegans, that is indicative of hibernation and energy conservation in times of stress. This suggests that CFS could be an ancient hibernation-like mechanism for survival during times of environmental stress through hypometabolism and the reduction of cellular functions, , in a similar way to C. elegans. This leaves patients with the chronic symptoms of fatigue, memory loss, and muscle pain.

caenorhabditis_elegans

C. elegans– the nematode worm model organism that exhibits ‘dauer’ – a state induced by environmental pressure that lowers metabolism for survival through hibernation.

However, the causes of this metabolic change are still unknown- why are these patients’ metabolisms convinced there is enough environmental pressure to go into hibernation?

Why is this important?

The results from this paper provide a multitude more ways investigate CFS, and potentially find its cause. Each individual patient had unique combinations and levels of down-regulated metabolites, and further investigation could lead to unique tailored treatment to improve quality of life. However, there still needs to be a lot more research- larger trial groups with more sample sizes, and further inquiry into the effects of an altered metabolome on cellular function.  These findings contribute to the argument that it is not the cause of CFS that defines the disease, but the symptoms and signature low metabolism that accompanies it. Hopefully, in time these results will significantly advance our understanding of the causes and treatment of CFS.


The paper: Naviaux et al. Metabolic features of Chronic Fatigue Syndrome. 2016. PNAS.

Image: C. elegans, Wikimedia commons

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