The immune system has a lot of responsibility defending your body from injury and disease. It attacks pathogens like bacteria, viruses, parasites or fungi, recognizes and neutralizes harmful substances from the outside environment and fights disease-causing changes in the body such as cancer cells.
But what may not be as well-known is the immune system’s role in our psychological health. The immune system produces neurotransmitters like serotonin that affect your mood and is in turn influenced by the neurotransmitters released by the nervous system.
Unfortunately, stress can throw a wrench into the immune system’s complex and delicate workings…
Previous research shows stress can compromise the immune system’s ability to defend against disease — or even cause it to go haywire and cause rampant, damaging inflammation in the body.
One international team of researchers became interested in exploring the complicated connection between stress, the immune system and the brain. And what they discovered could have far-reaching implications for the treatment of depression…
The effect of MMP-8 on behavior
In a study, the researchers uncovered a novel mechanism known as matrix metalloproteinaise-8 (MMP-8), an enzyme released from polymorphonuclear neutrophils (PMN) that plays an important part in mediating inflammation.
Neutrophils, in general, are the body’s first responders to acute (sudden) inflammation. In chronic inflammation, their role is less understood, but they are associated with inflammatory diseases.
“We were able to show that stress increases the amount of [MMP-8], an enzyme in the blood of mice,” says first author Flurin Cathomas. “The same changes were found in patients with depression.”
When MMP-8 travels from the blood to the brain, it alters the functioning of certain neurons. The study found that this leads to behavioral changes in the affected mice; they withdraw and avoid social contact — which mimics behavior seen in humans with depression.
To prove that MMP-8 was responsible for the behavioral changes, the team removed the MMP-8 gene from some of the mice in the study. Compared to the control group, these mice did not display negative behavioral changes related to stress.
“Blood analyses of patients with depression indicate that the findings from the mouse models are also relevant for humans: both the monocytes and MMP-8 were increased in the blood of people with depression in comparison to healthy participants,” Cathomas says.
The findings are novel in two respects, according to Cathomas. “Firstly, they indicate a new ‘body-mind mechanism’, which might be relevant not only for stress-related mental illness, but also for other diseases that affect both the immune and nervous systems,” he says. And secondly, he adds, identifying the specific MMP-8 protein could be a potential starting point to develop new treatments for depression.
Keep stress from hacking your immune system
More studies are required before these results translate to changes in clinical practice. But Cathomas notes this study “once again demonstrates the importance of the interaction between the immune system and the brain in the development of psychiatric disorders.
“These insights are already being incorporated into psychiatric treatment today,” he adds.
For now, there are many steps you can take on your own to help reduce stress that both support the health of your immune system and help fight depression. Here are a few to start with:
- Do yoga. If you want to bust stress, get a mood boost from endorphins and strengthen your immune system, yoga is the way to go. Attend a nearby class or check out some videos online to get started.
- Get some vitamin D. This “sunshine vitamin” not only helps support the immune system, but it also helps protect against stress and depressive symptoms. The easiest way to get vitamin D is through exposure to sunlight. But if you aren’t getting enough sun exposure, consider supplementing.
- Boost your omega–3s. Omega-3 fatty acids are powerful anti-inflammatory agents, and that may play some role in their ability to relieve depression on par with Prozac.
- Support your thyroid and adrenal glands. When your adrenals are constantly stressed, this sets off an autoimmune inflammatory response in your entire body which results in a constant assault of cortisol, the stress hormone. The adrenal-hypothalamus-pituitary feedback loop regulates the secretion of the stress hormone cortisol.
- Try frankincense essential oil. While there are separate essential oils that help with anxiety, depression and immune system support, frankincense may get to the root. Some research has shown that the Boswellic acid from frankincense stops inflammatory enzymes from working. Adding the essential oil to a diffuser can be very relaxing. Supplements are also available as Boswellia extract.
If feeling depressed, don’t hesitate to reach out to a healthcare professional.
Sources:
Stress influences brain and psyche via immune system — EurekAlert!
Circulating myeloid-derived MMP8 in stress susceptibility and depression — Nature
How does the immune system work? — InformedHealth.org
The Role of MMP8 in Cancer: A Systematic Review — International Journal of Molecular Sciences
Nature’s Medicine: Essential Oils for Depression, Anxiety and Immune Health — Cannizzaro Integrative Pediatric Center