How biophysical in vivo testing techniques can be used to characterize full thickness skin equivalents.
BACKGROUND
The reliability of the biophysical properties of skin equivalents (SEs) remains a challenge for medical applications and for product efficacy tests following the European Directive 2003/15/EC2 on the prohibition of animal experiments for cosmetic products.


METHODS
We propose to adapt the biophysical in vivo testing techniques to compare full thickness model growth vs. time. The interest in using such techniques lies in possible comparisons between in vivo and in vitro skin as well as monitoring samples over the culture time.


RESULTS
High frequency ultrasound technique, optical coherence tomography (OCT), and laser scanning microscopy were used to analyze SEs morphology at days D42 and D60 whereas their microstructure was assessed through transmission electron microscopy and classical histology. A correlation between these observations and mechanical measurements has been proposed so as to underline the consequence of both the development of the dermis elastic fibers and the epidermis differentiation.


CONCLUSIONS
Ultrasounds measurements show a highly homogeneous dermis whereas the OCT technique clearly distinguishes the stratum corneum and the living epidermis. The increase in the thicknesses of these layers as well as the growth in elastin and collagen fibers results in strong modifications of the samples mechanical properties.
Centre de Microscopie Electronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Toulouse III, Université P. Sabatier, Toulouse, France.
A
A
Houcine
Pixience, Toulouse, France.
A
A
Delalleau
Banque de tissus et cellules, Laboratoire des substituts cutanés, Hospices Civils de Lyon and LBTI, UMR 5305, Lyon, France.
S
S
Heraud
Département Pharmacologie, Pierre Fabre, R&D PFDC, Toulouse Cedex, France.
B
B
Guiraud
Centre de Microscopie Electronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Toulouse III, Université P. Sabatier, Toulouse, France.
B
B
Payre
Département Pharmacologie, Pierre Fabre, R&D PFDC, Toulouse Cedex, France.
H
H
Duplan
Centre de Microscopie Electronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Toulouse III, Université P. Sabatier, Toulouse, France.|CHU Toulouse et INSERM U 1037, Toulouse Cedex, France.
M-B
MB
Delisle
Banque de tissus et cellules, Laboratoire des substituts cutanés, Hospices Civils de Lyon and LBTI, UMR 5305, Lyon, France.
O
O
Damour
Département Pharmacologie, Pierre Fabre, R&D PFDC, Toulouse Cedex, France.
S
S
Bessou-Touya
D021522:Bioartificial Organs / Q000009:adverse effects*; D001705:Bioprosthesis / Q000145:classification*; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D018613:Microscopy, Confocal / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D012867:Skin / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012879:Skin Physiological Phenomena; D017768:Skin, Artificial / Q000145:classification*; D023822:Tissue Engineering / Q000379:methods; D041623:Tomography, Optical Coherence / Q000379:methods; D014463:Ultrasonography / Q000379:methods
biophysical measurements; culture time; imaging; mechanical properties; skin equivalents