Markers to Evaluate the Quality and Self-Renewing Potential of Engineered Human Skin Substitutes In Vitro and after Transplantation

Abstract

We screened a series of antibodies for their exclusive binding to the human hair follicle bulge. In a second step these antibodies were to be used to identify basal keratinocytes and potential epithelial stem cells in the human epidermis and in engineered skin substitutes. Of all the antibodies screened, we identified only one, designated C8/144B, that exclusively recognized the hair follicle bulge. However, C8/144B-binding cells were never detected in the human epidermal stratum basale. In the bulge C8/144B-binding cells gave rise to cytokeratin 19-positive cells, which were also tracked in the outer root sheath between bulge and the hair follicle matrix. Remarkably, cytokeratin 19-expressing cells were never detected in the hair follicle infundibulum. Yet, cytokeratin 19-expressing keratinocytes were found in the epidermal stratum basale of normal skin as a subpopulation of cytokeratin 15-positive (not C8/144B-positive) basal keratinocytes. Cytokeratin 19/cytokeratin 15-positive keratinocytes decreased significantly with age. We suggest that cytokeratin 19-expressing cells represent a subpopulation of basal keratinocytes in neonates and young children (up to 1.5 years) that is particularly adapted to the lateral expansion of growing skin. Our data show that cytokeratin 19 in combination with cytokeratin 15 is an important marker to routinely monitor epidermal homeostasis and (at least indirectly) the self-renewing potential of engineered skin.

Translating the combination of gene therapy and tissue engineering for treating recessive dystrophic epidermolysis bullosa

“…Transduced keratinocyte stem cells were preserved in tissue-engineered skin substitutes Long-term expression of a transgene in keratinocytes is only possible if stem cells are transduced. For this reason, the concomitant expression of HA-COLVII with keratin 19 (K19), which is expressed by keratinocyte stem cells Michel et al, 1996;Pontiggia et al, 2009), was investigated. With both transduction enhancers, HA-COLVII expression was detected in K19-positive basal keratinocytes of the TES epidermis (Fig.…”

Stammzellen im Nagelorgan

“…In Übereinstimmung mit der Literatur [11] ist nur Zytokeratin 15 (Klon LHK15) in der Basalzellschicht der dorsalen und ventralen proximalen Nagelfalte durchgehend nachweisbar, nicht jedoch Zytokeratin 19 und PHLDA1. Ersteres fi ndet sich in der dorsalen proximalen Nagelfalte älterer Schwangerschaftswochen nur noch in vereinzelten Zellen an der Spitze der ekkrinen Leisten und dürfte damit wahrscheinlich Merkelzellen darstellen [19].…”

The Influence of Stromal Cells on the Pigmentation of Tissue-Engineered Dermo-Epidermal Skin Grafts

“…Since several years, we are investigating diverse characteristics and properties of dermo-epidermal skin substitutes (DESS) for future clinical application to full-thickness skin defects. [11][12][13][14][15] The importance of site-specific cellular epidermal and dermal components has been shown in the context of reproducing the original donor skin color in our pigmented skin substitutes. 16 Moreover, the applied preclinical model enables us to analyze the influence of different fibroblast populations in an in vivo setting.…”