Investigation of the skin barrier properties of healthy subjects and atopic eczema patients

Atopic eczema (AE) is one of the most common skin diseases. It has been related
to factors such as allergens and irritants and is associated with red and dry
skin. The occurrence of AE is increasing rapidly. For many years it has been
thought that these allergens and irritants initiate the disease via the
airways. However, in recent years there is strong evidence that the disease is
triggered by an impaired barrier function of the skin. As a result of this
impaired barrier function, the transport of allergens across the skin is
facilitated, which increases the risk of developing eczema.
The skin barrier is located in the outermost layer of the skin, the stratum
corneum (SC), which consists of dead cells embedded in lipid regions. The
corneocytes are almost impermeable for compounds and the lipid regions are the
only continuous structure in SC. For this reason the transport of substances
applied onto the skin is mainly directed along the tortuous pathway of the
intercellular lipid regions. This demonstrates that the hydrophobic lipids are
considered to play a crucial role in the barrier function of the skin. The
major lipid classes in SC are ceramides (CER), cholesterol (CHOL) and free
fatty acids (FFA) in an approximately equimolar ratio.
In this project, we will use confocal Raman spectroscopy, electron diffraction
(ED) and infrared spectroscopy in order to determine the lateral packing of the
SC lipids in AE patients and healthy subjects in vivo. In addition, we will
study the lipid composition of SC lipids in AE patients and healthy subjects by
liquid chromatography/mass spectrometry (LC/MS). Lipid organization and
composition will be related to water and NMF-levels in the SC and will be
measured as a function of depth in SC, since it is known that the lipid
organization may alter as a function of depth. This is of interest since an
altered lipid composition may result in an change in lipid organization, which
may lead to a reduced barrier function of the skin.
This in vivo study will be the first in which various bioanalytical techniques
are combined to thoroughly investigate the lipid organization and composition
in SC of AE patients and healthy subjects.

The objective of tje study is to investigate the lipid organization and
composition in the SC of AE patients and healthy subjects in relation to the
water and nmf-content in the SC.

Etiological

Measurements wil take place during one day. At the end of the day, a biopsy
will be taken. There are no risks involved in participating in the study.