Study: SLS causes prolonged skin barrier disruption for AD mice.

Link:  Increased skin barrier disruption by sodium lauryl sulfate in mice expressing a constitutively active STAT6 in T cells

Important notes:

Sodium lauryl sulfate (SLS), an anionic detergent, is a common ingredient found in various skin and hair care products. It has been shown to trigger a prolonged barrier disruption of the skin that lasts up to a week following a single 24-hour application and thus is used in studies involving skin barrier damage {Patil, 1995 #31}.

…….

Next, we assessed whether the increased epidermal thickness in SLS-treated STAT6VT mice correlated with increased cellular proliferation (Fig. 3A). Ki-67 is a nuclear protein that provides a reliable method to evaluate the growth fraction of cells during late S, M and G2 phases {Gerdes, 1984 #33}. As shown in Fig. 3B, quantification of Ki-67 expression levels demonstrated increased levels of this nuclear protein in the epidermis of STAT6VT compared to WT mice. However, these differences do not appear to be linked to the addition of an irritant as control-treated STAT6VT skin exhibited elevated Ki-67 levels (p=0.07). These findings suggest that the increased epidermal thickness in SLS-treated STAT6VT mice is primarily driven by epidermal cell hypertrophy rather than an increase in cellular proliferation.

Discussion

…..Of particular note, the TEWL of the STAT6VT transgenic mice was slower to return to baseline levels during the interval period between treatments, unlike WT mice. The present studies extend recently published work that showed that although retinoic acid treatment resulted in equal levels of barrier disruption, TEWL recovery after treatment was delayed in STAT6VT transgenic mice {Sehra, 2010 #27}.

….

Histology and epidermal thickness measurements support the notion that STAT6VT transgenic mice treated with a topical irritant resulted in the development of dermatitis. Immunohistochemical studies examining the expression of Ki-67 suggest that a component of the epidermal thickness could be due to increased keratinocyte proliferation. It is also possible that epidermal thickening is due to decreased apoptosis of keratinocytes, or increased differentiation of basal keratinocytes into the more mature layers of the stratum corneum. Another group has similarly shown that irritant skin reactions caused from repeated applications of SLS result in increased epidermal thickness {Anderson, 1986 #67}. Previous and current studies by our group have shown that STAT6VT murine ear tissue, even in mice without obvious lesions, exhibits a marked thickening of the dermis and epidermiswith cellular infiltration of eosinophils and lymphocytes {Sehra, 2010 #27}. Our findings further corroborate that the STAT6VT transgenic murine model is clinically relevant as this model system provides a platform for studying the complex interactions between pharmacological and immunological abnormalities observed in patients with atopic dermatitis.

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Thoughts:

It has been known that SLS is an irritant and SLS is widely available in our daily skincare products such as shampoo, body soap, hand wash etc. Do everything to avoid SLS.

The study of TEWL is interesting. It appears our goal for TSW sufferers is to recover to our normal baseline TEWL. Thus, any factors that can delay TEWL recovery should delay our healing progress. In my research thus far, the use of moisturizers, SLS, as well as TS disrupt or delay the TEWL recovery process. This may be a new angle at looking why we have varied recovery rates.

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5 thoughts on “Study: SLS causes prolonged skin barrier disruption for AD mice.

  1. well done. this is the most interesting and informative blog i have read on tsw and since i’ve been withdrawing i’ve been interested in this kind of readings. ill be sending you my good thoughts and hopes to heal. seriously though, as hard as it gets, it will get better and you will see the upside eventually despite how the skin may still look fucked up. im sure you understand though.

    • Thank you Charles for your endorsement. I find that my comfort in TSW is derived from researching and knowing all about TSW in a scientific / logical way.

      Back when I was ignorant and in the deep end of my withdrawals, there was just too much unknowns. No solid foundation to provide the basis for everything I do in order to improve my skin. I hope this blog help readers in the same way these research helped me too!

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