Artificial skin equivalent differentiation depends on fibroblast donor site: use of eyelid fibroblasts.

Our objective was to construct and explore human skin equivalents from several normal and pathologic donor skin sites to determine if the fibroblast origin influences epidermal differentiation. Also, we wanted to find out if fibroblasts from some donor sites produced epidermis of superior quality for plastic surgery repairs. Skin equivalents were constructed from 15 normal skin specimens, 9 normal eyelid specimens, 15 lesional skin specimens taken from patients with psoriasis, and 4 specimens from keloid scars. Results show that the tissue origin of the donor fibroblasts determines epidermal differentiation and the time period for regeneration. Eyelid fibroblasts were very dependable in establishing well-differentiated skin equivalents in all nine specimens. Our findings contribute to the accumulated knowledge of wound healing and should also be of value in skin grafting, especially when large areas are denuded as in burns, severe trauma, or cancer ablation.

Interleukin-8 is induced in skin equivalents and is highest in those derived from psoriatic fibroblasts.

Interleukin-8 (IL-8) may be important in psoriasis as it is expressed in the stratum granulosum, attracts polymorphonuclear cells, and stimulates angiogenesis and keratinocyte mitogenesis. To study intrinsic cutaneous factors in psoriasis, we constructed skin equivalents from psoriatic or adult control fibroblasts with normal foreskin keratinocytes. IL-8 levels were measured in supernatants by enzyme-linked immunosorbent assay and in skin equivalents by immunohistochemistry and in situ hybridization. IL-8 was highly induced in skin equivalents compared to cells grown alone. Epidermal stratification varied among fibroblast lines and was correlated with IL-8 levels, but lesional and nonlesional psoriatic skin equivalents from the same donor were similar. Six fibroblast lines (two psoriasis lesion and four normal) supported only monolayers, while 12 lines (seven psoriasis lesion and five normal) produced stratification. Mean IL-8 levels were significantly lower in dermal equivalents of the first group than the second (0.78 +/- 0.40 vs 3.93 +/- 2.83 ng per ml, mean +/- SD, p = 0.01, analysis of variance). Significantly more IL-8 was secreted by psoriatic than normal fibroblast skin equivalents over 14 d (p = 0.015) with greatest differences at 1 and 4 d. Psoriatic IL-8 levels peaked first and remained increased. IL-8 protein and mRNA were initially strongest in dermal fibroblasts, and at the dermal-epidermal interface. Diffuse epidermal expression was replaced by accentuation in the stratum granulosum. Psoriatic skin equivalents were thicker, had more intense IL-8 staining, and developed invagination. We hypothesize that an IL-8 paracrine loop between fibroblasts and keratinocytes may play a key role in epidermal regeneration in the skin equivalent, in normal wound healing, and in the determination of an intrinsic psoriatic wound-healing phenotype.