A group of researchers has recently discovered the source of a detrimental immune reaction to psychological stress. The study had shown that proteins given off by brown adipose tissue are accountable for triggering inflammation in response to severe stress.
Cortisol is the dominant hormone released during the body's "fight or flight" response to stress. It is an active anti-inflammatory hormone that significantly reduces inflammation. It also regulates sugar and metabolism for the productive management of psychological stress.
Experts have found it hard to understand why stress tends to heighten inflammatory issues such as rheumatoid arthritis and other autoimmune diseases. This is partly because stress hormones like adrenaline and cortisol are intended to suppress the immune system and lessen inflammation.
According to a co-author of the study, Andrew Wang from Yale University, he and his colleagues have seen stressful events that worsened the inflammatory disease, and it always didn't make sense to them.
The full findings of the study were published in the journal Cell on June 30, 2020.
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The IL-6 Pathway
In their study, the scientists focused on an immune system cell called the cytokine interleukin-6 (IL-6). The cell is said to trigger inflammation when the body is dealing with psychological stress.
Earlier studies have demonstrated that IL-6, which is normally secreted in response to infection, also plays a role in certain conditions. Furthermore, it can also be observed in autoimmune diseases, diabetes, obesity, cancer, anxiety, and depression.
The researchers focused their attention on the relationship between stress and IL-6 after they noticed high levels of the mice's proteins during a stressful procedure.
In a succession of experiments with mice, the researchers discovered that IL-6 was brought about by stress and aggravated inflammatory responses.
Moreover, the scientists were surprised to discover that IL-6 was emitted in brown fat cells, mostly regulating body temperature and metabolism.
The research team established that when signals from the brain to brown fat cells were obstructed, stressful conditions had no impact on inflammatory responses. Furthermore, the scientists were able to identify that IL-6 also helps the body increase its glucose production by apprehending possible threats.
The Role of IL-6 in Mental Health Disorders Involving Stress
In their experiment, the researchers found that when IL-6 production was blocked in mice, they were less agitated when situated in a stressful environment. The experts speculate that IL-6 may play a role in mental health conditions such as anxiety and depression.
Dr. Wang says that many symptoms of depression, like the loss of appetite and sex drive, copy those caused by infections like the flu. These alleged "sickness behaviors" can be induced by IL-6.
There are drugs designed to treat autoimmune diseases such as rheumatoid arthritis that block the activity of IL-6. Initial findings suggest that these drugs could help ease the symptoms of depression, according to the researchers.
Reina Desrouleaux, another co-author of the study, concludes that their research on the role of IL-6 outside of immunity is exciting as it contributes to filling up the knowledge gap on the subject.
