An examination of psychological stress and its effects on the mitochondrial DNA

Background: With improvements in cellular stress measurement, current findings firmly implicate mitochondrial activity in cell stress reactions. Recent studies have highlighted the effects of psychological stress on mitochondria in terms of oxidative deterioration and crisis signalling. However, these studies have mainly assessed this relationship using the Trier Social Stress Test (TSST), while a variety of methods have been applied in blood sample analyses. This study contributes to the progression of existing studies as a partial replication that employs a different experimental stress protocol (based on the International Affective Picture System) (IAPS), a younger student population and similar blood sample analyses. Specifically, the relationship between cell-free mitochondria (via analyses of ccf-mtDNA levels following experimental stress) and acute psychological stress was evaluated in healthy female university-student participants.

Methods: This study partially replicates the Trumpff et al., 2019 study. Fourteen female participants (n=14) were recruited on a university campus via posters and emails. All participants completed baseline questionnaires and two blood draws, with a 10-minute experimental stressor occurring between the pre-stress blood draw and post-stress blood draw. Blood samples were obtained at: i) baseline prior to the stressor and ii) +30 mins post stressor, to evaluate the changes in ccf-mtDNA levels associated with acute psychological stress.

Results: A paired two-tailed t-test was used to assess the difference between the pre and post-blood samples, There was a statistically significant increase (P < 0.01) (a 53% increase) in ccf-mtDNA +30 mins after the psychological stressor.

Conclusion: The present findings suggest that acute psychological stress is associated with a statistically significant increase in cell-free mitochondrial DNA (ccf-mt-DNA) in young healthy female university students.