Canadian researchers identify how inflammatory disease causes fatigue

It's a long ways away from any clinical application, but I still thought this was exciting news!

A research team from the University of Calgary has identified how immune cells infiltrate into the brain during experimental liver inflammation, potentially explaining why people with inflammatory diseases develop symptoms such as fatigue. This new understanding could lead to treatments that improve the quality of life for patients with chronic inflammatory diseases.

“Sickness behaviors, such as fatigue and malaise, significantly impact the health related quality of life of individuals with these diseases. Our findings further our understanding of how patients with inflammatory disease may develop these symptoms and may generate potential new avenues for the treatment of these often incapacitating symptoms,” says Dr. Mark Swain, the study’s senior author, and a hepatologist at the University of Calgary, Faculty of Medicine.

Fatigue, lethargy and loss of interest in social activities are commonly encountered in patient’s suffering from inflammatory diseases such as hepatitis, arthritis, and inflammatory bowel disease (IBD).

The study published in the February 18th issue of The Journal of Neuroscience demonstrates the existence of a communication pathway between the inflamed liver and the brain.

Using a mouse model of inflammatory liver injury, Dr. Swain’s group found that white blood cells called monocytes infiltrated the brain, establishing a communication pathway between the inflamed liver and the brain. Moreover, in mice with inflamed livers blocking the recruitment of monocytes from the blood into the brain reduced sickness behaviours. These findings support previous research demonstrating the presence of immune cells in the brain following organ inflammation, challenging the long held belief that the blood-brain barrier prevents cells from accessing the brain.
Image showing a brain blood vessel (BV; outlined in red) and a monocyte within the blood vessel and adherent to the vessel wall

The study was supported by the Canadian Institutes of Health Research, The Alberta Heritage Foundation for Medical Research and the Canadian Liver Foundation.

Swain is a professor in the Department of Medicine at the University of Calgary and a researcher with the Calvin, Phoebe and Joan Snyder Institute of Infection, Immunity & Inflammation.