Skin disorders : how to characterize stratum corneum mechanical properties ?

The main barrier of the skin is located in the outermost layer of the skin, the stratum corneum.

Several damages in stratum corneum involve skin barrier disorders as Atopic Dermatitis, complex disease due to multiple factors (immunologic, genetic, environnemental).

During formation of the stratum corneum barrier, terminally differentiated keratinocytes continue their maturation process within the dead superficial epidermal layer. Morphological studies of isolated human corneocytes have revealed differences between cornified envelopes purified from the deep and superficial stratum corneum.

BioMeca®‘s solutions

BioMeca® is able to measure the stiffness of corneocytes from health subjects and to compare it to the values obtained in non-involved skin of patients with Atopic Dermatitis, all analysed according to the status of filaggrin gene mutation.

Biological models : native human corneocytes harvested by tape-stripping from different stratum corneum depths.

Methods :

Stiffness tomography using atomic force microscopy (AFM) on mid-thickness stratum corneum cells harvested with tape stripping.

Corneocytes in the stratum corneum of non-lesional atopic dermatitis skin showed a highly significant decrease of stiffness when compared to that found in healthy subjects, and so independent from the presence or not of filaggrin mutations.

CONCLUSION

Apparent fragility of cells constituting the stratum corneum barrier can be observed in non-lesional skin of atopic dermatitis patients. It is associated with the presence of an active pathological process, no matter whether atopic dermatosis has been propped up by filaggrin mutations or other unknown factors. Should such mechanical characteristics of corneocytes be constitutive or dependant on systemic inflammatory state remains to be determined.

This proposed approach can be potentially used for minimally invasive evaluation of various skin conditions such as aging, skin hydration, and pathologies linked to stratum corneum.