Salt Accumulation May Be a Factor in Atopic Dermatitis

VIENNA — Patients with atopic dermatitis had elevated amounts of sodium compared with non‐lesional atopic and healthy skin, researchers reported here.

In a tissue sample-based study, sodium chloride levels in the skin reached an average of 39 μg/mg in atopic dermatitis patients with skin lesions versus no appreciable sodium accumulation of sodium in non-lesional skin and in healthy skin (P=0.01), according to Christina Zielinski, MD, of the Technical University of Munich, and colleagues.

“Sodium chloride enhanced IL‐4 and IL‐13 production while suppressing IFN‐g production in effector T cells. It diverted alternative T cell fates into the Th2 cell phenotype and also induced de novo Th2 cell polarization from naïve T cell precursors,” they stated in a presentation at the Inflammatory Skin Disease Summit (ISDS).

“Mechanistically, it exerted its effects via the osmosensitive transcription factor NFAT5 and the kinase SGK‐1, which regulated Th2 signature cytokines and master transcription factors in hyperosmolar salt conditions,” they added.

Zielinski noted that there was a non-significant increase of about 8 μg/mg in the skin of people diagnosed with psoriasis.

ISDS session co-chair Tove Agner, MD, of the University of Copenhagen, told MedPage Today that the study was “provocative. It is fantastic that someone takes something that is so new and so old at the same time.”

But she cautioned that “this hypothesis needs a lot more work. One of the member of the [ISDS] audience made a good point that the authors could not differentiate between the epidermis, the upper part of the skin, and the dermis as to where the sample comes from. We need to know this before we can really trust these results.”

Zielinski pointed out that pediatrician Heinrich Finkelstein (1865-1942) suggested that dietary salt reduction could improve eczema in patients. More recently, research demonstrated the influence of sodium on the pathophysiology of multiple sclerosis.

But “the nature of [environmental] factors and the mode of action by which they induce the type 2 immune deviation, which is characteristic of atopic diseases, remains unclear…Here, we demonstrate that sodium chloride also potently promotes Th2 cell responses on multiple regulatory levels,” Zielinski’s group wrote.

They performed biopsies on 21 organs and tissues from human cadavers, and found that salt accumulation was highest in the skin and kidneys, but was still distributed through out the body.

Zielinski suggested clinicians evaluate sodium chloride consumption in patients with atopic dermatitis because “our data propose ionic signaling through sodium chloride as a novel checkpoint and potential therapeutic target for type 2 immunity and its associated allergic diseases.”