and Galactooligosaccharide Improve Skin Barrier Dysfunction and Atopic Dermatitis-like Skin.

Purpose: The beneficial effects of a combination therapy using and galactooligosaccharide (GOS) for the treatment of atopic dermatitis (AD) have not been elucidated.

Methods: Gene expressions of interleukin (IL)-4 and IL-13 from peripheral blood mononuclear cells and fecal abundance of . from 12-month-old infants were evaluated. Human primary epidermal keratinocytes (HEKs) and hairless mice were treated with , GOS, -derived extracellular vesicles (BLEVs), dinitrochlorobenzene (DNCB), or a synbiotic mixture of . and GOS. Expression of epidermal barrier proteins and cytokines as well as serum immunoglobulin E (IgE) levels were analyzed in HEKs and mice. Dermatitis scores, transepidermal water loss (TEWL), epidermal thickness, and fecal abundance were evaluated in mice.

Results: Fecal abundance of . was negatively correlated with blood expression in infants. or BLEVs increased expression of filaggrin () and loricrin () in HEKs. . increased the efficacy of GOS to upregulate and expressions in HEKs. Oral administration of GOS increased fecal abundance of . in mice. Oral administration of . attenuated DNCB-induced skin inflammation, abnormal TEWL, AD-like skin, and deficiency of epidermal barrier proteins. Moreover, the combination of and GOS showed greater effects to improve DNCB-induced skin inflammation, abnormal TEWL, AD-like skin, serum IgE levels, over-expression, and the deficiency of epidermal barrier proteins than the administration of alone.

Conclusions: and GOS improve DNCB-induced skin barrier dysfunction and AD-like skin.