Development and Validation of Human Psoriatic Skin Equivalents

Abstract

Psoriasis is an inflammatory skin disease driven by aberrant interactions between the epithelium and the immune system. Anti-psoriatic drugs can therefore target either the keratinocytes or the immunocytes. Here we sought to develop an in vitro reconstructed skin model that would display the molecular characteristics of psoriatic epidermis in a controlled manner, allowing the screening of anti-psoriatic drugs and providing a model in which to study the biology of this disease. Human skin equivalents generated from normal human adult keratinocytes after air exposure and stimulation by keratinocyte growth factor and epidermal growth factor displayed the correct morphological and molecular characteristics of normal human epidermis whereas the psoriasis-associated proteins, hBD-2, SKALP/elafin, and CK16, were absent. Skin equivalents generated from foreskin keratinocytes were clearly abnormal both morphologically and with respect to gene expression. When normal skin equivalents derived from adult keratinocytes were stimulated with psoriasis-associated cytokines

Psoriasis Risk Genes of the Late Cornified Envelope-3 Group Are Distinctly Expressed Compared with Genes of Other LCE Groups

“…12 In brief, de-epidermized human dermis, 0.8 mm thick and 8 mm in diameter, was used as a scaffold for keratinocytes. Constructs were cultured submerged for 3 days in tissue culture inserts in a 24-well plate, and subsequently the medium level was lowered to enable air exposure to induce terminal differentiation.…”

In Vivo and In Vitro Models of Psoriasis

“…Results showed that after the addition of a proinflammatory cytokine mixture, the expression of psoriasis-associated proteins hBD-2 and SKALP/elafin for the pro-inflammatory cytokines IL-8 and of TNF-were increased in the skin equivalent, as well as keratinocyte hyperproliferation cells. Tjabringa et al also showed that the addition of all-trans retinoic acid inhibits the expression of psoriasis-associated proteins hBD-2 and SKALP/elafin in cytokine-stimulated skin equivalents and reduces expression of the normal differentiation marker: keratin 10, as such as acanthosis can be observed in psoriatic skin in vivo (Tjabringa, et al, 2008).…”

“…This model allowed controlled induction of psoriasis-associated features and gene expression by the addition of relevant pro-inflammatory cytokines (TNF-, IL-1 , IL-6 and IL-22) and primary keratinocytes obtained from donors without history of psoriasis. To produce this model, a hollow metal ring was placed on de-epidermized dermis and keratinocytes were seeded within the ring (Tjabringa, et al, 2008). Results showed that after the addition of a proinflammatory cytokine mixture, the expression of psoriasis-associated proteins hBD-2 and SKALP/elafin for the pro-inflammatory cytokines IL-8 and of TNF-were increased in the skin equivalent, as well as keratinocyte hyperproliferation cells.…”

“…- (Mils, et al, 1994) Keratinocytes + + ? - (Tjabringa, et al, 2008) Collagen gel Organ culture ? + ?…”

“…No distinguishing histological or biochemical criteria could be established between normal and psoriatic equivalents. Keratinocytes on de-epidermized dermis Another reconstructed epidermal model was developed with normal adult human keratinocytes seeded on de-epidermized dermis (Tjabringa et al, 2008). This model allowed controlled induction of psoriasis-associated features and gene expression by the addition of relevant pro-inflammatory cytokines (TNF-, IL-1 , IL-6 and IL-22) and primary keratinocytes obtained from donors without history of psoriasis.…”