3 ms·

The arrow of causation — if there is any — likely goes in the direction of aged skin causing greater microbiome diversity, than microbiome diversity causing age

The arrow of causation — if there is any — likely goes in the direction of aged skin causing greater microbiome diversity, than microbiome diversity causing age related skin changes.

voisin 3y ago
What’s your logic here?
- nostromo 3y ago
  I agree it seems more likely that causation flows from aging to microbiome changes, not the opposite. When your skin ages, the biome changes as your barrier is degraded, as your skin thins, as inflammation increases as your immune system ages, and as the surface becomes rougher and more difficult to clean.
- BenFranklin100 3y ago
  We know many many aspects of skin aging aren’t due to microbiome changes: UV exposure breaks down elastin fibers and disrupts the collagen network; fibroblasts are known to have age related changes; fat layers below the dermis thin with age; skin becomes less oily and thus more prone to dehydration. These independent aging factors would change the environment microbes inhabit and thus very likely have causative effects on the microbiome overall. One might argue that a changing microbiome could in turn have second order deleterious effects on the skin. I suspect this could be a reason L’Oreal is sponsoring the research. But this is speculative at this point, and a quick read of the Abstract and Discussion didn’t reveal any such findings.
echelon 3y ago
I'd wager that increased microbiome diversity --> increased inflammation --> additional local tissue damage. Microbiome changes may have something to do with an aging immune system too [1]. There are probably a large number of things happening here, in addition to the traditional skin aging mechanisms. [1] https://www.sciencedirect.com/science/article/abs/pii/S0952791511000653 https://www.sciencedirect.com/science/article/abs/pii/S09527...
webnrrd2k 3y ago
I agree. Plus, there also simple things like plain cirulation. Skin is fed by blood, and all the various juices that sluce up from below. It seems to my very uneducated understanding that this would have a far greater impact overall.
- webnrrd2k 3y ago
  Now that I think about it, an easy test could've comparing the skin of people who do/don't regularly swim in chlorinated pools. I'd think that the chlorine would pretty much nuke any surface microbiome. So the comparison would be fairly straightforward. Hardly definite, with all the possible confounding factors and all, but certainly an easy way to test for plausibility.
  - h0l0cube 3y ago
    I wouldn't trust any study in concert with a cosmetics company to be impartial/sensible science. They're aiming for a result that increases revenue for their products (or leads to products that can generate revenue for them), and this would drive how the study is constructed.
    - hackernewds 3y ago
      so anyone else can run that study. seems cheap to execute
    - BenFranklin100 3y ago
      L’Oreal wants to make money by selling products that improve a person’s appearance. Having a better understanding of the biology behind aging skin could aid that endeavor, so I wouldn’t write this research off as a matter of course.
      - h0l0cube 3y ago
        I doubt they would support a study that possibly conclude to use less of their products, or they might test a number of hypotheses and then only pursue a published study on whatever makes cosmetic products appear better. It's sensible to write off any study that has such a clear conflict of interest in doing actual science.
dartharva 3y ago
Seems so. From the original paper: "During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function."
ptoo 3y ago
I'm leaning towards there being no causation between skin microbiome and wrinkles. Did anyone in the study have botox? Crow's feet wrinkles are generally caused by two things: UV damage, and movement of facial muscles breaking down collagen. Which naturally tend to increase with age. So that's where I'd wager the causation is. If a person uses factor 50 every day on their face and gets biyearly botox injections on their crow's feet area, they'll likely have no prominent wrinkles but they will still be old and with a greater skin microbiome.
- m463 3y ago
  I thought smoking had a pronounced effect on skin aging.

The arrow of causation — if there is any — likely goes in the direction of aged skin causing greater microbiome diversity, than microbiome diversity causing age related skin changes.

voisin 3y ago

What’s your logic here?

nostromo 3y ago
I agree it seems more likely that causation flows from aging to microbiome changes, not the opposite. When your skin ages, the biome changes as your barrier is degraded, as your skin thins, as inflammation increases as your immune system ages, and as the surface becomes rougher and more difficult to clean.
BenFranklin100 3y ago
We know many many aspects of skin aging aren’t due to microbiome changes: UV exposure breaks down elastin fibers and disrupts the collagen network; fibroblasts are known to have age related changes; fat layers below the dermis thin with age; skin becomes less oily and thus more prone to dehydration. These independent aging factors would change the environment microbes inhabit and thus very likely have causative effects on the microbiome overall. One might argue that a changing microbiome could in turn have second order deleterious effects on the skin. I suspect this could be a reason L’Oreal is sponsoring the research. But this is speculative at this point, and a quick read of the Abstract and Discussion didn’t reveal any such findings.

echelon 3y ago

I'd wager that increased microbiome diversity --> increased inflammation --> additional local tissue damage. Microbiome changes may have something to do with an aging immune system too [1]. There are probably a large number of things happening here, in addition to the traditional skin aging mechanisms. [1] https://www.sciencedirect.com/science/article/abs/pii/S0952791511000653 https://www.sciencedirect.com/science/article/abs/pii/S09527...

webnrrd2k 3y ago

I agree. Plus, there also simple things like plain cirulation. Skin is fed by blood, and all the various juices that sluce up from below. It seems to my very uneducated understanding that this would have a far greater impact overall.

webnrrd2k 3y ago
Now that I think about it, an easy test could've comparing the skin of people who do/don't regularly swim in chlorinated pools. I'd think that the chlorine would pretty much nuke any surface microbiome. So the comparison would be fairly straightforward. Hardly definite, with all the possible confounding factors and all, but certainly an easy way to test for plausibility.
- h0l0cube 3y ago
  I wouldn't trust any study in concert with a cosmetics company to be impartial/sensible science. They're aiming for a result that increases revenue for their products (or leads to products that can generate revenue for them), and this would drive how the study is constructed.
  - hackernewds 3y ago
    so anyone else can run that study. seems cheap to execute
  - BenFranklin100 3y ago
    L’Oreal wants to make money by selling products that improve a person’s appearance. Having a better understanding of the biology behind aging skin could aid that endeavor, so I wouldn’t write this research off as a matter of course.
    - h0l0cube 3y ago
      I doubt they would support a study that possibly conclude to use less of their products, or they might test a number of hypotheses and then only pursue a published study on whatever makes cosmetic products appear better. It's sensible to write off any study that has such a clear conflict of interest in doing actual science.

dartharva 3y ago

Seems so. From the original paper: "During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function."

ptoo 3y ago

I'm leaning towards there being no causation between skin microbiome and wrinkles. Did anyone in the study have botox? Crow's feet wrinkles are generally caused by two things: UV damage, and movement of facial muscles breaking down collagen. Which naturally tend to increase with age. So that's where I'd wager the causation is. If a person uses factor 50 every day on their face and gets biyearly botox injections on their crow's feet area, they'll likely have no prominent wrinkles but they will still be old and with a greater skin microbiome.

m463 3y ago
I thought smoking had a pronounced effect on skin aging.