Abstract:
Skin barrier disruption plays a role in the pathogenesis of atopic dermatitis (AD) in humans. However, little is
known about skin barrier (dys-) function in Canine Atopic Dermatitis. The properties of lipids located in the
outermost layer of the skin, the stratum corneum (SC) are considered to be important for the barrier. In the
present study the lipid composition and lipid organization of the SC of AD dogs and control dogs were examined.
The lipid composition of lesional AD skin as compared to control skin, showed a reduced free fatty acid level and
a decreased ratio of ceramide[NS] C44/C34, in which C44 and C34 are the total numbers of carbon atoms of the
sphingosine (S) and non-hydroxy (N) acyl chains. As a consequence of the observed changes in lipid composition
in AD lesional skin the lamellar organization of lipids altered and a shift from orthorhombic to hexagonal lipid
packing was monitored. Simultaneously an increased conformational disordering occurred. These changes are
expected to compromise the integrity of the skin barrier. The C44/C34 chain length ratio of ceramide[NS] also
showed a decreasing nonlinear relationship with the AD severity score (CADESI). Taken together, canine atopic
skin showed alterations in SC lipid properties, similar to the changes observed in atopic dermatitis in humans,
that correlated with a disruption of the skin barrier. Hence lipids play an important role in the pathogenesis of
Canine Atopic Dermatitis.
