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Acute psychological stress increases serum circulating cell-free mitochondrial DNA, 2019, Picard et al

Discussion in 'Other health news and research' started by Andy, Apr 29, 2019.

  1. Andy

    Andy Committee Member

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    No idea if this is good science or not, but thought it might be of interest.
    Paywall, https://www.sciencedirect.com/science/article/pii/S0306453018312149
    Sci hub, https://sci-hub.se/10.1016/j.psyneuen.2019.03.026
     
    Andy, Apr 29, 2019
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  2. Hutan

    Hutan Moderator Staff Member

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    I guess it's not surprising that a psychological threat might result in the same response as a physical threat. And I guess it's useful to know that that response involves the ejection of mitochondrial DNA from cells.

    However, the stressor in this case was 2 minutes preparation for a defence of an imaginary false allegation of shoplifting or a traffic incident, with 3 minutes delivering it. Therefore, it's arguable that it was just the cognitive demands of the task that caused the response. Supporting that idea is the fact that in the second session, when people were told that they had performed below average in the first session, there wasn't a bigger mitochondrial DNA response, as might be expected if psychological stress was the cause. Personally, I wouldn't be particularly stressed by this exercise; it has no serious consequence. A lot of people who are perfectly healthy would routinely deal with similarly demanding tasks every day.

    The paper suggests that mitochondrial DNA is released in response to exercise, infection or physical injury. Maybe this signalling occurs in response to all sorts of stressors, mild or otherwise? Maybe a jog around the block or a game of scrabble cause the same response?
     
    Hutan, Apr 29, 2019
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  3. Amw66

    Amw66 Senior Member (Voting Rights)

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    What surprised me was that this is news.

    Having read and been told that your body does not differentiate between physical and psychological stress, that cortisol modulates over 300 genes, that in rat models stress is epigenetically expressed and for some genes heritable, i had perhaps assumed that this had been checked out before and signalling was more " known " .

    I guess " never assume" is the takeaway from this.
     
    Amw66, Apr 30, 2019
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  4. Hutan

    Hutan Moderator Staff Member

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    Just had a thought - the participants fasted overnight and through the morning until after the trial. They had an IV catheter inserted into the antecubital fossa of one arm and had three blood samples taken. Who knows if any of that had more of an impact than giving a 3 minute presentation?

    Not the authors of this study because they had no controls.
     
    Hutan, Apr 30, 2019
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  5. Andy

    Andy Committee Member

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    So they could well have found evidence for the start of starvation mode. I did wonder whether this study would be any better than most ME neuropsych stuff, the evidence suggests not.
     
    Andy, Apr 30, 2019
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  6. Woolie

    Woolie Senior Member

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    Great points, @Hutan.

    I do wonder why these stress studies never include any sort of control for the non-stress elements of the task. For a start, how about walking once around the block or collecting up some cushions from the floor?

    These days I wonder whether the whole idea of psychological "stress" just ties us in knots and gets us nowhere. Its such a vague concept. Something to do with psychological demands that a person has difficulty meeting. There seem to be so many different types of situations that count as stressful, and they don't have that much in common. I wonder if it would be more useful to use specific terms - like "pressure to perform", "experiencing negative feedback", "enduring discomfort" and so forth.

    Getting rid of the term psychological stress and replacing it with more specific things might help to prevent the inevitable slide between psychological and physiological/biological forms of stress.
     
    Woolie, Apr 30, 2019
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  7. Snow Leopard

    Snow Leopard Senior Member (Voting Rights)

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    Indeed. It is inappropriate to derive conclusions from pilot studies like this.
     
    Snow Leopard, Apr 30, 2019
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  8. Forbin

    Forbin Senior Member (Voting Rights)

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    There was an article on this research in Scientific American last September: Brain’s Dumped DNA May Lead to Stress, Depression
    The article doesn't get into this, but could the biological stress caused by the immune system's reaction to mitochondrial DNA in the bloodstream wind up causing the release of more mDNA into the bloodstream? So, following some kind of significant triggering event, like an infection, could you wind up in a loop where there's enough mDNA being released into the bloodstream to become self-perpetuating?
     
    Last edited: May 14, 2019
    Forbin, May 14, 2019
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