How hormones may modulate human skin pigmentation in melasma: An in vitro perspective

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

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Desmosomal distribution in the epidermis of a non-contracting human skin equivalent

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124884 ◽

1992 ◽

Vol 50 (1) ◽

pp. 896-897

Author(s):

L.X. Oakford ◽

S.D. Dimitrijevich ◽

R. Gracy

Keyword(s):

Human Skin ◽

Basal Layer ◽

Skin Equivalent ◽

Tissue Component ◽

Intact Skin ◽

Similar Sequence ◽

Sequence Of Events ◽

Suprabasal Keratinocytes ◽

Human Skin Equivalent

In intact skin the epidermal layer is a dynamic tissue component which is maintained by a basal layer of mitotically active cells. The protective upper epidermis, the stratum corneum, is generated by differentiation of the suprabasal keratinocytes which eventually desquamate as anuclear comeocytes. A similar sequence of events is observed in vitro in the non-contracting human skin equivalent (HSE) which was developed in this lab (1). As a part of the definition process for this model of living skin we are examining its ultrastructural features. Since desmosomes are important in maintaining cell-cell interactions in stratified epithelia their distribution in HSE was examined.

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Expression of intercellular adhesion molecule-1 in UVA-irradiated human skin cells in vitro and in vivo

British Journal of Dermatology ◽

10.1046/j.1365-2133.1996.d01-982.x ◽

1996 ◽

Vol 135 (2) ◽

pp. 241-247 ◽

Cited By ~ 1

Author(s):

G. TREINA ◽

C. SCALETTA ◽

A. FOURTANIER ◽

S. SEITE ◽

E. FRENK ◽

...

Keyword(s):

Human Skin ◽

Adhesion Molecule ◽

Intercellular Adhesion ◽

Intercellular Adhesion Molecule ◽

Intercellular Adhesion Molecule 1 ◽

Skin Cells ◽

Human Skin Cells

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Human Skin-Derived Fibroblasts Acquire In Vitro Anti-Tumor Potential after Priming with Paclitaxel

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520611313030015 ◽

2013 ◽

Vol 13 (3) ◽

pp. 523-530 ◽

Cited By ~ 1

Author(s):

Augusto Pessina ◽

Valentina Cocce ◽

Arianna Bonomi ◽

Loredana Cavicchini ◽

Francesca Sisto ◽

...

Keyword(s):

Human Skin

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The Effect of Practolol, In Vitro Generated Metabolites of Practolol and Chemical Analogues on the Rate of Growth of Human Skin Fibroblasts

Alternatives to Laboratory Animals ◽

10.1177/026119298401200205 ◽

1984 ◽

Vol 12 (2) ◽

pp. 89-97

Author(s):

Graham R. Elliott ◽

H.E. Amos ◽

James W. Bridges

Keyword(s):

Human Skin ◽

Psoriasis Patient ◽

Skin Fibroblasts ◽

Human Skin Fibroblasts ◽

Cell Type ◽

Normal Human Skin ◽

Rate Of Growth ◽

Structural Analogues ◽

Normal Human

The rate of growth of normal human skin fibroblasts was inhibited in a dose related, reversible, fashion by practolol (N-4-(2-hydroxy)-3 (1-methyl)-aminopropoxyphenylacetamine) (ID50 1.35 ± 0.14 x 10-3M), propranolol (1-(isopropylamino)-3(1-naphthyl-oxy)-2-propranolol) (ID50 0.145 ± 0.02 x 10-3M) and paracetamol (N-(4-hydroxyphenyl) acetamide) (ID50 0.85 ± 0.2 x 10-3M). Skin fibroblasts isolated from a psoriasis patient were more sensitive towards practolol (ID50 0.48 ± 0.14 x 10-3M) and propranolol (ID50 0.032 ± 0.002 x 10-3M), but less sensitive towards paracetamol (ID50 1.3 ± 0.07 x 10-3M). In vitro generated metabolites of practolol, using normal or Arochlor 1254-pretreated hamster liver preparations, and structural analogues of practolol had no effect upon the growth of either cell type.

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