Immune Systems Are Damaged as a Result of Prolonged Stress

Stress is more than emotional or psychological, it affects us physically through the immune system too.

We know that stress affects us psychologically, but the truth is that it also affects us physically. Chronic stress in particular can be detrimental.

Depression is one of mental health issues due to which people go through chronic stress which effects their immune system in the long run.

The study we will talk about today has done experiments on mice that showed that after being subjected to stress a special chemical is released that enters parts of the brain through the blood stream. Following this, the behaviour of the mice changed, they became withdrawn and avoided social contact which has been seen in people with depression.

According to the international research team led by the University of Zurich (UZH), and the University Hospital of Psychiatry Zurich (PUK) and the Icahn School of Medicine at Mount Sinai, New York, it means that they “were able to show that stress increases the amount of the matrix metalloproteinase-8 (MMP-8), an enzyme in the blood of mice. The same changes were found in patients with depression,” as was said by the first author Flurin Cathomas.

This implicates that these findings can reflect why humans with depression behave withdrawn and avoid social contact.

If taken as fact, these findings can change how we understand other stress-related mental health issues and diseases that affect immune and nervous systems. This is because this study brings us a new “body-mind mechanism” through which we can look and analyse them in a new way.

To understand the more technical side, the researchers analysed the process of how the chemicals travel to the brain and found that with the increase of stress, a white blood cell called monocyte starts to migrate at an increased rate towards the vascular system of the brain and into the reward centre regions. Monocytes are also responsible for the production of MMP-8 which then participates in restructuring and regulating the frame around the neurons of the brain called extracellular matrix.

After looking more into it, they made sure that this process in fact was what was causing the asocial and withdrawn behaviour in mice by removing the MMP-8 from some of the mice. When compared it was obvious that the mice that now didn’t have the MMP-8 in their systems did not show the stress-related negative behaviours.

To then also make sure the same chemical was present in people when their body was faced with stress, the researchers tested individuals diagnosed with depression for MMP-8 and found that indeed they had an increased amount of them in their blood.

However, to implement these results into medical practice a lot more experiments have to be completed to make sure that they would be safe for humans. Even so the insights coming from this study are already “being incorporated into psychiatric treatment today,” as was said by Cathomas on the PUK’s special award for integrative care.

Right now, to move this research forward, the researchers are planning to look into two different aspects, one being the extent to which stimulating certain areas of the brain affect the immune system. And the second being if behaviour of depressed patients would change as a result of changes in the immune system cells.