Source Of Melanocytes Research Articles

The Source of Melanocytes in Ortho- and Heterotopic Tail Regenerates of Axolotls and the Dependence of the Regenerative Response on the Presence of Neural Tissue

We studied the regeneration of orthotopic and heterotopic tails in larval axolotls. First, we analyzed tail regeneration following reciprocal exchange of cuffs of tail integument between dark-colored (wild-type) and yellow-colored (hybrid) larval animals. Second, we studied tail regeneration in larval axolotls following transplantation of cuffs of tail integument from metamorphosed dark-colored conspecifics and from an adult fire salamander. In all cases, the amputation planes involved the transplanted integumental cuffs. In the first experiment, the regenerated tails showed the color of the host animals, not that of the transplanted cuffs. This suggests that the melanocytes of the regenerated tails were derived from the host hypodermis. Following transplantation of metamorphosed skin from axolotls and a fire salamander onto larval axolotls, the metamorphosed epidermis reverted to a larval condition. This indicates that the state of differentiation of the metamorphosed epidermis was not permanent. Rather, in order to maintain the metamorphosed epidermal structure, a continuous exposure of the animals to sufficient levels of thyroid hormones was required. Transplantation of tail buds from yellow-colored onto dark-colored axolotl embryos caused the formation of yellow-colored tails both in the head and the anterior limb region of the hosts. Incomplete resection of these heterotopic tails was followed by tail regeneration, while no tail regeneration occurred following complete resection of the heterotopic tails. Successful tail regeneration depended on the presence of neural tissue along the resection plane.

LEVELS OF CERTAIN HORMONES AND RECEPTORS IN TUMOR AND PERITUMORAL AREA IN BALB/C NUDE FEMALE MICE WITH MULTIPLE PRIMARY MALIGNANT PROCESS DEVELOPING ON THE BACKGROUND OF PRIMARY IMMUNODEFICIENCY

Primary immunodeficiency is one of the reasons for the development of primary multiple malignant tumors.
 The aim of the study is to examine the levels of certain hormones and their receptors in the tissue and peritumoral area of B16/F10 melanoma and Lewis lung carcinoma (LLC) in case of isolated and combined subcutaneous growth in female mice with T-cell immunodeficiency.
 Materials and Methods. BALB/c Nude mice were divided into groups: intact group; 2 control groups (Group 1 with B16/F10 subcutaneous inoculation, Group 2 with LLC subcutaneous inoculation); main group (animals with LLC+B16/F10 inoculation). The ELISA method was used to determine the levels of free testosterone (Tf.), estrone (E1), prolactin (PRL), estrogen receptors (REα and REβ), androgen receptors (RA) and progesterone receptors (RP4) (Cassabio, China). Statistical processing of the obtained results was carried out on a personal computer using STATISTICA 10.0, parametric Student's test and nonparametric Wilcoxon-Mann-Whitney test.
 Results. In the main group, life expectancy reduced due to melanoma growth by 1.8 times and LLC decrease by 2.3 times. In animals with LLC+B16/F10, compared to those with an only one tumor growth variant, estrone level in tumors decreased, but free testosterone level increased. Melanoma growth in animals with LLC+B16/F10 was accompanied by an increase in prolactin level and some sex steroid receptors in the tumor tissue, its peritumoral area, and skin not affected by the malignant process. A decrease of Lewis carcinoma in females of the main group was accompanied by a decrease of all the studied receptors and hormones both in the tumor and its peritumoral area.
 Conclusions. Melanoma growth is probably associated with a high prolactin level and sex steroid receptors in unaffected skin, being a source of melanocytes, the cells from which this tumor develops.

Follicular cell suspension: A new surgical modality for the treatment of vitiligo

Follicular cell suspension is a recently described technique of cellular suspension for treatment of stable vitiligo. Its uniqueness lies in the fact that hair-follicle melanocytes from the outer root sheath are utilized as a source of melanocytes unlike traditional methods, which use epidermal melanocytes. Few distinctive properties of these hair-follicle melanocytes make them an attractive source of donor cells over epidermal melanocytes. In this article, we briefly discuss the theoretical basis, procedure and advantages of this novel technique.

A zebrafish model for nevus regeneration

A zebrafish model for nevus regeneration

Surgical management of vitiligo

Vitiligo is a common condition characterized by hypopigmented and/or depigmented spots on the skin, affecting approximately 1–2% of the world population. Until approximately 30 years ago, it was exclusively treated by medical therapies. The most commonly used medical therapies include topical steroids, calcineurin inhibitors and phototherapy. Lesions on the face and neck respond the best to medical therapies, followed by lesions on the proximal extremities and trunk, while those distributed over acral parts of extremities and nonhairy areas, such as the wrist, feet and male genitals, respond poorly. Surgical methods complement medical therapies by providing melanocytes to these refractory lesions, and are indicated for unilateral segmental and clinically stable bilateral vitiligo, refractory to medical treatment. Tissue-grafting methods include minigrafting or punch grafting, epidermal grafting and split thickness grafting. These methods use full-thickness punch grafts, roof of epidermal blisters and shave biopsy samples, respectively, as the source of melanocytes. Cellular grafting includes noncultured and cultured melanocytes/keratinocytes suspensions obtained from trypsinizing the shaved skin biopsy sample as a source of melanocytes. Recent advances over the years have enabled dermatologists to treat extensive areas located on any anatomic site in a single operative session by surgical intervention. The purpose of this review is to describe the selection criteria for the surgical treatment, their utility and limitations in the various types of vitiligo.

Melanogenesis in cultures of peripheral nervous tissue: I. The origin and prospective fate of cells giving rise to melanocytes

Chick embryo spinal ganglia, peripheral nerves, and connective tissue usually associated with ganglia were cultured separately using several combinations of media and substrata. Melanocytes appear in cultures of both ganglia and peripheral nerves. The only cell type common to both the ganglion and peripheral nerve that could account for the observed pigment cells was the population of small cells with intensely staining nuclei that normally associates closely with nerve cell bodies and fibers. These cells could be distinguished morphologically from fibroblastic cells, which originated in the connective tissue capsule and did not undergo melanogenesis. We conclude that these small cells are supportive (Schwann, satellite, and perineurial) cell precursors and are one source of melanocytes in cultured peripheral nervous tissue.

Polymelanosomes of the melanocyte and their substructures.

THE importance of studying visceral melanocytes has already been emphasized1–4 and the liver of Amphiuma tridactylum—a rich source of melanocytes—is a suitable material to use. The melanoprotein of the liver of Amphiuma is very similar to that of human liver melanoma5, and the melanin polymer (free from protein) closely resembles that of human substantia nigra pigment and synthetic catecholamine pigment formed by incubating the various amines with a mitochondrial preparation containing monoamine oxidase4. Structural and functional studies of the hepatic melanocytes of Amphiuma may therefore have a bearing on other pigmentary systems. We have reported (refs. 1 and 6 and unpublished work of Prasad) that the melanocytes of Amphiuma constitute about 20 per cent of the liver cell population (hepatocytes and melanocytes). Most of these melanocytes (70–80 per cent of total pigment cell population) are lightly pigmented and have an abundance of melanin-containing organelles which we named polymelanosomes6. The darkly pigmented cells contain closely packed granules lying freely in the cytoplasm, but no polymelanosomes. There is some morphological evidence that melanin-synthesis occurs in the polymelanosomes, and the light melanocytes which have an abundance of these organelles probably represent the younger form6. Polymelanosomes possess three mitochondrial enzymes, monoamine oxidase, cytochrome oxidase and succinic oxidase7.