Psoriatic architecture constructed by epidermal remodeling.
Epidermal remodeling is the concept that epidermal architecture is determined by a simple self-organizing mechanism; epidermal hyperproliferation constructs typical psoriatic architecture. This is based on the assumption that the enlargements in both the two-dimensional proliferative compartment (basal cell layer) and three-dimensional whole epidermal volume coexist. During this process, the dermal papillae become markedly, but passively, expanded by enlargement of the proliferative compartment. This creates a considerable shrinkage force against the crowded basal cell layer, which is forced to lose adherence to the dermal extracellular matrix (ECM). This results in anoikis, a type of apoptosis characterized by cell detachment, and, consequently, a markedly diminished epidermal turnover time in psoriasis. The papillary shrinkage force also explains the fact that dermal papillary height does not exceed a certain limit. At the cessation of hyperproliferation a normalisation remodeling takes place toward normal tissue architecture. Thus the concept of epidermal remodeling explains the self-organizing mechanism of the architectural change in psoriasis, which is essentially a reversible disorder depending on epidermal hyperproliferation.
Iizuka
Hajime
H
Department of Dermatology, Asahikawa Medical College, Midorigaoka-Higashi 2-1-1, Asahikawa, Japan. derma@mail.asahikawa-med.ac.jp
Takahashi
Hidetoshi
H
Ishida-Yamamoto
Akemi
A
D000818:Animals; D023102:Anoikis; D002455:Cell Division; D004817:Epidermis / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D011565:Psoriasis / Q000473:pathology* / Q000503:physiopathology; D013234:Stem Cells / Q000473:pathology