Social stress induces neurovascular pathology promoting depression, 2017, Russo et al

Paywalled at https://www.nature.com/articles/s41593-017-0010-3

New Scientist article on this, https://www.newscientist.com/articl...ss-makes-your-brain-vulnerable-to-depression/

 

Doesn't every human in the planet experience what they call social stress at some point?

Everyone at some point has parents or guardians or older siblings, teachers, bosses. Not all of these more powerful people will be kind, gentle and understanding.

If this is the case why are there not more cases of depression?

Perhaps I've misread it but the new scientist article seems to assume that increased IL-6 and depression are the whole story. Is it not possible that both could be symptomatic of some other, as yet unidentified, abnormality?

 

But how would we quantify that? What is the exact amount of stress required? In the study itself, not all mice developed symptoms. To my mind, an equally valid question would be why are there not fewer cases of depression?

 

I've read the abstract and the NS article.

The question I want to ask is, how do they know it is the stress that causes the blood brain barrier (bbb) to be more leaky etc. Couldn't it equally be that there are a proportion of mice (and humans) who have a leakier bbb and are therefore more susceptible to these chemical and mood changes.

Since they can't tell if a mouse has a leaky bbb except by killing it, they can't know whether it was already leaky before the experiment started in those mice. In other words, does the stress cause the leakiness and hence the depression, or does the stress act on an already leaky bbb to trigger the depression.

Or have I missed something (quite likely).

 

@Trish, I can't access the paper, but the NS article mentions two other groups of mice being included as part of the experiment,

If mice already had leaky BBB prior to the stress, then there should be mice with leaky BBBs in all three groups. Presumably, then, only the mice in the group that were put under stress had leaky BBBs on examination (or only to a significant extent/a significant number of mice).

Without being able to look at the whole paper, it's hard to know anything for sure, though.

 

Mouse 'models' like this are always self-fulfilling and tell us nothing about causation in human disease.