Transplantation of Human Melanocytes

Recent advances in the culturing of pigment cells from human beings have made it possible to begin the transplantation of autologous melanocytes into areas of skin that are hypopigmented. In a patient with piebaldism we were able to take pigment cells from a shave biopsy of the normally pigmented skin of the back, expand the cells in culture, and return them to an area devoid of pigment cells and get a perfect take. To grow the cells in culture we used 12-O-tetradecanoyl-phorbol-13-acetate (TPA) as well as cholera toxin and isobutylmethyl xanthine. At this time, one can substitute basic fibroblast growth factor for TPA. The procedure of using autologous pigment cell cultures opens the door for further advances in the treatment of patients who do not have melanocytes in certain areas of the skin, as seen in patients with vitiligo or piebaldism, or as a consequence of severe mechanical or thermal trauma

The Distribution of Melanocytes in the Leptomeninges of the Human Brain

The purpose of this study was to determine the qualitative and quantitative distribution of melanocytes in human leptomeninges by histochemical and ultrastructural techniques and to search for melanocytes in the mesothelial linings of the pleural and peritoneal cavities. Knowledge of the extracutaneous distribution of pigment cells will facilitate the interpretation of systemic symptoms in depigmentation disorders, such as vitiligo and the Vogt-Koyanagi-Harada syndrome.In 15 brains examined, leptomeningeal pigment cells were found principally over the ventrolateral surfaces of the medulla oblongata. Only isolated pigment-containing cells were found in the meninges covering other parts of the brain. The mean number of pigment cells in the medullary meninges of 5 brains was 325/mm2 ± 96. The presence of melanosomes as single, membrane- bound granules in all stages of melanization confirms that the melanin-containing dendritic cells of the leptomeninges are melanocytes and not macrophages.No pigmented cells were observed in the pleural or peritoneal samples examined

Epithelial Growth by Rat Vibrissae Follicles In Vitro Requires Mesenchymal Contact via Native Extracellular Matrix

An in vitro assay utilizing the rat vibrissa anagen follicle as a model for studying the epithelial-mesenchymal interactions (EMI) in hair growth is described. Through selective disruption of the epithelial-mesenchymal interface, we investigate whether the specialized extracellular matrix (ECM) of the dermal papilla and basement membrane zone (BMZ) serves a crucial function in hair follicle EMI. Epithelial bulbs incubated intact within their follicular sheaths incorporate thymidine primarily into cells of the hair matrix and outer root sheath, as shown by autoradiography. However, after removal of its mesenchymal associations (dermal papilla and extrabulbar connective tissue), the epithelial bulb showed no incorporation. Neither externally added collagen (type I or IV) nor the basement membrane components in Matrigel could substitute for the growth supporting influence of native surrounding stroma. Mechanical separation of the bulb from the dermal papilla in the basement membrane zone inhibited thymidine incorporation by the epithelium even though mesenchyme was still in close proximity. Enzymatic digestion of the dermal papilla ECM and the basal lamina by Dispase, a fibronectinase and type IV collagenase, also inhibited bulb growth without evidence of cytotoxicity. These experiments suggest that direct epithelial to mesenchymal contact is required for the support of follicular epithelial growth in vitro and that specific ECM components, possibly fibronectin and/or type IV collagen, rather than diffusable factors alone, play a crucial role in the mechanism of hair follicle EMI. The in vitro system described here provides an alternative to developmental EMI models and may serve as a valuable tool for studying EMI in the adult mammalian organism