Illuminating the Effects of Stress at a Deeper Level

An essential component of organelles, mitochondria provide the fuel and power to sustain life from an intracellular level within our bodies. As such, they play a role in many bodily functions - of interest is their contribution to the stress response. Recent research has successfully demonstrated mitochondrial defects caused genetically or biochemically, can be a causal factor for particular clinical disorders, and can result in changes in brain function, amongst an array of other factors that are known to be implicated in stress pathophysiology. A well-established approach towards examining stress pathophysiology has been in focusing on the impact of stress on the brain, endocrine and immune system. In this review, Picard & McEwen sought to delve in further, to examine what is happening at the intracellular level within these systems and how mitochondrial function may be involved in the neurobiology of stress. They explored various studies which utilized male laboratory animals and applied acute and chronic types of stressors to examine their impact on mitochondrial function within the brain.

The effects of stress on mitochondrial biology is well documented through this review. Generally, both acute and chronic types of stressors can affect mitochondria, but notably, chronic stressors in particular may be implicated in negative molecular and functional changes. There are three key takeaways that address the relationship between mitochondria and stress. First, it was found that chronic stressors lessens mitochondrial energy production. Conversely, acute stressors may improve mitochondrial function. Since chronic stressors result in the opposite effect, this points to an inverted U-shaped relationship between duration of stress and mitochondrial functionality. Lastly, it was discovered that behavioural, genetic and dietary factors may decrease stress vulnerability for mitochondria, in buffering its functionality in times of stressors. In conclusion, it was shown that acute and chronic stressors may show benefit and harm respectively, alongside the idea that stress vulnerability of mitochondria could be governed by lifestyle and genetic factors. These findings illustrate the involvement of mitochondrial biology within the stress pathophysiology framework. Thus, this review enriches the current stress pathophysiology literature and contributes to our understanding of stress by examining the topic through a biological lens.

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Source:

• Picard, M., & McEwen, B. S. (2018). Psychological Stress and Mitochondria: A Systematic Review. Psychosomatic Medicine, 80(2), 141-153.