Keratinocytes Regulate Melanocyte Number in Human Fetal and Neonatal Skin Equivalents

Scott, Glynis; Haake, Anne R.

doi:10.1111/1523-1747.ep12486726

Cited by 72 publications

(41 citation statements)

References 25 publications

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“…Our pigmented skin equivalent was constructed in this way, and was stratified with dendritic melanocytes located in the basal keratinocyte layer. Pigmented skin equivalents have been used for the study of the pigmentation induced by ultra-violet light [1Á/3], for the growth of keratinocytes and melanocytes and their interactions [4,5], for the effects of chemicals on the growth of melanocytes [6], and to study the mechanism of melanosomes transfer [7]. However, there has been no report to our knowledge on their use for the study of congenital hyperpigmentary disorders.…”

Section: Keratinocytementioning

confidence: 99%

“…However, there has been no report to our knowledge on their use for the study of congenital hyperpigmentary disorders. Several methods have been described for their construction; some reported the use of collagen sponge [17] or dermis with the epidermis removed [5] in place of collagen-gel, and a graft of epidermis [4,17] in place of the seeding of melanocytes and keratinocytes. The large advantage of our skin equivalent is that keratinocytes, melanocytes, and fibroblasts can be combined independently, and cells other than keratinocytes, melanocytes, and fibroblasts can be excluded.…”

Section: Keratinocytementioning

confidence: 99%

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Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation

Okazaki¹,

Suzuki²,

Harii³

2005

Scandinavian Journal of Plastic and Reconstructive Surgery and

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We have constructed a pigmented skin equivalent and used it to study the hyperpigmentation seen in café-au-lait macules to elucidate whether the pigmented skin equivalent could be used as a model of congenital hyperpigmentary disorders. When we used fibroblasts derived from café-au-lait macules of neurofibromatosis type 1, the amount of pigment was significantly greater than in models using cells derived from normal skin. Quantities of pigment were not seen when keratinocytes derived from solitary café-au-lait macules were used, a possible reason being that keratinocytes on the skin equivalent are in a proliferating condition and are not well-differentiated enough to act on other cells. Our results suggested that our pigmented skin equivalent is useful for the study of congenital hyperpigmentary disorders, although insufficient differentiation of keratinocytes might be a disadvantage.

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Section: Keratinocytementioning

confidence: 99%

Section: Keratinocytementioning

confidence: 99%

Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation

Okazaki¹,

Suzuki²,

Harii³

2005

Scandinavian Journal of Plastic and Reconstructive Surgery and

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“…In parallel with these works, more complex models have been improved with the object of a better understanding of this cell type within its original functional unit, the epidermal melanin unit (EMU). In vitro reconstruction of pigmented epidermis or skin equivalents is now possible (Bessou et al, 1995;Scott and Haake, 1991;Todd et al, 1993;Topol et al, 1986;Valyi-Nagy et al, 1990) and opens up new perspectives for the understanding of interactions between melanocytes and keratinocytes in melanization (paracrine control).…”

Section: Introductionmentioning

confidence: 99%

Stereological image analysis of cultured human melanocytes observed by transmission electron microscopy

Donois

Freund

Surlève-Bazeille

et al. 1997

Microsc. Res. Tech.

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The aims of the study were to write an image analysis (IA) program allowing the stereological quantification of human epidermal melanocyte melanization at the ultrastructural level and to specify the suitable preparative methods, in keeping with IA limits and stereological principles. Micrographs of cultured human melanocytes obtained in transmission electron microscopy were digitized with a scanner. The key step of the designed IA program is a thresholding based on the gray levels. Hence, gray level histograms (pixel frequency as a function of gray level) of melanocyte images exhibit a peak specific to melanin. The gray level thresholding used consists in isolating the melanin pixels that form profiles on a binary image and in storing the numerical data produced for a given melanocyte profile. These primary data are used to calculate numerous parameters via stereology with melanocyte cytoplasm and melanized melanosome as main reference spaces. The most important stereological parameters obtained are v (mi,cy) (melanin volume per average cell), v (mi,m) (melanin volume per average melanized melanosome), and n m (number of melanized melanosomes per average cell), and their validity is discussed. Melanocytes embedded in situ were abandoned for stereological reasons but pelleted melanocytes were found suitable. Using this computerized tool and stereology, we are able to perform quantitative studies producing varied data even from small cell samples. To our knowledge, this is the first stereological approach for quantifying intracellular melanization. A quantitative comparison of spectrophotometrical results (melanin assay) with stereological results obtained in ultraviolet B‐irradiated Caucasian epidermal melanocytes will be performed in order to appraise this method. Microsc. Res. Tech. 36:188–200, 1997. © 1997 Wiley‐Liss, Inc.

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“…Obviously, in terms of melanocyte number regulation, keratinocytes display a greater influence than fibroblasts as also suggested by Scott and Haake. 22 Moreover, we had already used melanocytes and keratinocytes in different ratios (1:1, 1:5, and 1:10) with nonpalmoplantar fibroblasts in DESS. 16 There, we also consistently detected a ratio of 1:5 (melanocytes:keratinocytes) after transplantation, indicating the establishment of a physiologically 1:5 melanocyte:keratinocyte ratio under homeostatic conditions.…”

mentioning

confidence: 99%

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

Biedermann

Böttcher‐Haberzeth

Klar

et al. 2015

Tissue Engineering Part A

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It has been shown in vitro that melanocyte proliferation and function in palmoplantar skin is regulated by mesenchymal factors derived from fibroblasts. In this study, we investigated in vivo the influence of mesenchymal-epithelial interactions in human tissue-engineered skin substitutes reconstructed from palmarand nonpalmoplantar-derived fibroblasts. Tissue-engineered dermo-epidermal analogs based on collagen type I hydrogels were populated with either human palmar or nonpalmoplantar fibroblasts and seeded with human nonpalmoplantar-derived melanocytes and keratinocytes. These skin substitutes were transplanted onto fullthickness skin wounds of immunoincompetent rats. Four weeks after transplantation the development of skin color was measured and grafts were excised and analyzed with regard to epidermal characteristics, in particular melanocyte number and function. Skin substitutes containing palmar-derived fibroblasts in comparison to nonpalmoplantar-derived fibroblasts showed (a) a significantly lighter pigmentation; (b) a reduced amount of epidermal melanin granules; and (c) a distinct melanosome expression. However, the number of melanocytes in the basal layer remained similar in both transplantation groups. These findings demonstrate that human palmar fibroblasts regulate the function of melanocytes in human pigmented dermo-epidermal skin substitutes after transplantation, whereas the number of melanocytes remains constant. This underscores the influence of sitespecific stromal cells and their importance when constructing skin substitutes for clinical application.

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Keratinocytes Regulate Melanocyte Number in Human Fetal and Neonatal Skin Equivalents

Cited by 72 publications

References 25 publications

Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation

Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation

Stereological image analysis of cultured human melanocytes observed by transmission electron microscopy

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

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