Defective barrier function accompanied by structural changes of psoriatic stratum corneum

Area of Science:

• Dermatology
• Biophysics
• Biochemistry

Background:

• Psoriasis vulgaris is a chronic inflammatory skin disease.
• Impaired skin barrier function is a hallmark of psoriasis, often measured by transepidermal water loss (TEWL).
• Limited research exists on other physical skin properties and components in psoriasis, such as stratum corneum hydration, natural moisturizing factor (NMF), free fatty acids (FFA), and protein secondary structure.

Purpose of the Study:

• To comprehensively compare physical skin properties and biochemical components between normal, involved, and uninvolved psoriatic skin.
• To investigate alterations in stratum corneum hydration, NMF, FFA, sebum content, and the ratio of β-sheet to α-helix structures in psoriatic skin.

Main Methods:

• Utilized a corneometer to measure TEWL and stratum corneum hydration.
• Employed attenuated total reflection-infrared spectrometry to assess NMF, FFA, β/α ratio, and sebum content.
• Compared measurements from patients with psoriasis vulgaris and healthy controls, analyzing involved and uninvolved skin.

Main Results:

• Involved psoriatic skin exhibited significantly increased TEWL and β/α ratio compared to uninvolved and normal skin.
• Stratum corneum hydration, NMF, and FFA were significantly decreased in involved psoriatic skin.
• TEWL and stratum corneum hydration levels normalized with clinical improvement of psoriatic lesions.

Conclusions:

• Psoriatic skin demonstrates defective barrier function and hydration.
• The secondary structure of stratum corneum proteins is altered in involved psoriatic skin.
• These findings highlight significant biophysical and biochemical changes in psoriatic skin, impacting its barrier integrity.