How stress can impact us on a cellular level

By JESSICA KASAMOTO | September 27, 2018

Stress seems to be an integral part of everyday life, especially on college campuses. While some students may cope with ups and downs better than others, most people are familiar with the physical and psychological responses that come with the pressures of everyday life. 

However, while stress is an unquestionably normalized emotion in modern society, scientists have linked stress with the exacerbation of various diseases, such as diabetes, cardiovascular disease, asthma and even infection by the human immunodeficiency virus (HIV). 

Reactions to stress are a part of what psychologists have deemed the “fight-or-flight” or acute stress response. This reaction was first described by Harvard Medical School Professor Walter Cannon in his 1920 publication Bodily Changes in Pain, Hunger, Fear and Rage. 

He describes the reaction as natural in humans and animals in response to threats or harmful events. The sympathetic nervous system is “primed” to protect the body for dealing with this threat — by either fighting it or fleeing from the scene. 

During this response, the adrenal medulla releases the neurotransmitter norepinephrine and the hormone epinephrine. This can cause blood vessels through the kidneys to inhibit nephrons, a structure in the kidneys that are vital in controlling the homeostasis of blood pressure. This is what causes common physical stress symptoms people experience, such as increased heart rate and blood pressure. 

But as scientists are beginning to realize, these responses do not come without a negative effect. 

The fight-or-flight response can often lead to mitochondrial damage in bodies. The mitochondria’s main function is to provide energy for the rest of the body through cellular respiration — the process where nutrients, such as glucose, are broken down and converted into adenosine triphosphate (ATP) and other usable forms of energy in the body. Since stress often results in these physical symptoms, the body needs to put more pressure on the mitochondria to make more energy.

This can be especially detrimental because the mitochondria has very little repair mechanisms. Recent research has shown that increased stress can lead to mitochondrial damage in regions of the brain such as the hippocampus and cortex. 

In addition, damaged mitochondria can also cause the literal spilling of DNA out of the mitochondria and into the rest of the cell, eventually finding its way to the bloodstream.

“This circulating mitochondrial DNA acts like a hormone,” Martin Picard, psychobiologist of Columbia University, said in an interview with Scientific America

He continues to explain that this circulating DNA seemingly mimics the release of cortisol, which at extremely high levels can lead to hypertension, high blood sugar, insulin resistance and even type 2 diabetes. 

To test this, Picard and his team devised a study where about 50 men and women gave a speech on camera defending themselves against a false accusation. Blood samples before and after the speech showed that, for most of the participants, the amount of mitochondrial DNA in the bloodstream doubled, even though the speech only lasted about five minutes. 

Picard’s study is not the only one that comes to this conclusion. 

A 2016 study published in Translational Psychiatry found that mitochondrial DNA levels in the bloodstream were elevated in 37 subjects who had recently attempted suicide. 

In addition, another 2018 study published in Neuropsychopharmacology demonstrated that subjects with depression generally had higher levels of mitochondrial DNA in their bloodstream, and it was even higher in those who were not responsive to their prescribed antidepressant medication. 

While this study is important for its elevated insight to the fight-or-flight response, it is also especially important in an academically rigorous and stressful environment like Hopkins. 

In an interview with The News-Letter, sophomore Hannah Wool explained her view on how findings like these should encourage the University to develop better mental health resources for students.

“The ways in which we talk — or don’t talk — about mental health on campus aren’t where they need to be. For one, there are many resources that just aren’t well-advertised,” Wool said.

In addition, Wool said that students may be unaware of the Counseling Center’s new services.

“Even if students do know about these resources and offices, they might have misconceptions about services offered; for instance, the Counseling Center now has significantly decreased wait times, no appointment required drop-in hours, but nearly every one of my second-year classmates has been surprised when I’ve mentioned it,” she said.

Wool continues to explain how she believes that such research revealing the negative impacts of stress should encourage people to “chip away” at the negative stigmas and normalizations behind stress and mental health on campus, especially humorous trivialization on the meme page. 

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