DOCSLIB.ORG

Enhancing the Care and Treatment of Skin of Color, Part 1: the Broad Scope of Pigmentary Disorders

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Enhancing the Care and Treatment of Skin of Color, Part 1: the Broad Scope of Pigmentary Disorders HIGHLIGHTING SKIN OF COLOR Enhancing the Care and Treatment of Skin of Color, Part 1: The Broad Scope of Pigmentary Disorders Susan C. Taylor, MD Scientific research and technologies related to reports that by 2050, approximately 50% of the skin pigmentation and dyschromias, which are US population will be composed of citizens with often key skin concerns for patients of color, skin of color.1 Skin of color is commonly defined have led to recent developments in skin care and as Fitzpatrick skin phototypes IV to VI.2 It should treatment. Differences and similarities between be noted that the Fitzpatrick scale describes the skin of color and white skin and current issues response of different skin types to UV light rather in the treatment of ethnic skin are reviewed. than the actual color of the skin. Recent research findings, such as the elucida- Despite the size and continuing growth of the tion of the protease-activated receptor 2 (PAR-2) skin of color population, most research related pathway and its role in pigmentation, and areas to the structure, function, and treatment of skin for further investigation, such as the pathogen- has been conducted in white subjects. Early data esis of pseudofolliculitis barbae (PFB), also are suggest that despite many similarities, there are discussed. Awareness of this information within differences between skin of color and white skin, the wider community of dermatologists, primary as well as different susceptibilities to skin condi- healthcare providers, and the media will help to tions. Although data from some of these seminal accomplish the objective of stimulating new pro- studies are conflicting or are based on small spective research. populations, they form an essential foundation for Cutis. 2005;76:249-255. continuing research.3-7 New technologies, such as diffuse reflectance spectroscopy (DRS), have permitted a greater understanding of the contribution of different New Horizons in Dermatology pigments to skin color.8 Recent research, such as People of color in the United States represent a the elucidation of the protease-activated receptor 2 wide range of ethnic groups, including African (PAR-2) pathway and its role in the regulation of Americans, Asians, Hispanics, Native Americans, pigmentation, has augmented our understanding and Pacific Islanders. The US Census Bureau of the interaction of the keratinocyte-melanocyte unit. This understanding may have an impact on the treatment of pigmentation disorders common Accepted for publication August 3, 2005. 9 From the Skin of Color Center, St Luke’s-Roosevelt Hospital in skin of color. Advanced research and emerg- Center, and the Department of Dermatology, Columbia University, ing technologies undoubtedly will provide increas- both in New York, New York; and Society Hill Dermatology, ing opportunities to deliver enhanced skin care, Philadelphia, Pennsylvania. therapies, and products to this growing segment This study was supported by Johnson & Johnson Consumer of the US population. Products Company, a Division of Johnson & Johnson Consumer Companies, Inc. Dr. Taylor is on the speakers bureau, and is an advisory board member and consultant for Johnson & Johnson. Ethnic Differences in Melanin Physiology Reprints: Susan C. Taylor, MD, Society Hill Dermatology, The most visible difference between skin of color 932 Pine St, Philadelphia, PA 19107 (e-mail: [email protected]). and white skin is the epidermal melanin content. VOLUME 76, OCTOBER 2005 249 Highlighting Skin of Color Melanosomes in the skin of individuals of African not correlate linearly with the calculated indices.10 descent are large and singly dispersed in kerati- DRS is a technology that uses reflected visible nocytes, whereas in white and Asian skin, the light to determine concentrations of melanin, oxy- melanosomes are aggregated within a surrounding hemoglobin, and deoxyhemoglobin, which are con- membrane.3,4 The epidermal melanin unit of skin tributors to skin color. Using DRS, it is possible of color contains more melanin and may undergo to distinguish between the vascular and the mela- slower degradation compared with other groups.5 nin components that contribute to erythema and Although increased melanin offers significant pho- pigmentation. It recently has been suggested that toprotection for deeply pigmented skin compared blood stasis, specifically the pooling of deoxyhe- with white skin, the potential for an exaggerated moglobin, can be confused with melanin pigmen- response by melanocytes to cutaneous trauma or tation.8 Hence, skin darkening does not depend inflammation can lead to a higher incidence of only on the concentration of melanin but is pigmentary disorders in skin of color.5,6 affected strongly by the concentration of deoxyhe- Skin pigmentation in response to UV irradiation moglobin in the superficial venous plexus. Future traditionally has been attributed to melanin; how- studies using DRS will be needed to separate the ever, advances in biomedical optics have permitted visual contributions of vascular and pigmentary a more detailed understanding of the contribution reactions in inflammatory conditions, especially in of other chromophores.8 Objective quantitative more deeply pigmented skin where erythema may evaluation of skin color reactions traditionally has be more difficult to visualize at the macro level used reflectance spectroscopy, either tristimulus in contrast with melanin pigmentation. reflectance colorimeters (Photovolt ColorWalk or the Minolta chromameter) or narrowband reflectance The Significance of Pigmentary Disorders spectrophotometers (DermaSpectrophotometer, the Pigmented skin frequently responds to trauma Erythema meter, or the Mexameter®). However, it or inflammation by becoming hyperpigmented or is reported that with both methods, what is clini- hypopigmented. Such pigmentary abnormalities cally perceived as erythema and pigmentation does can be distressing to individuals of color. In a Figure not available online Figure 1. The protease-activated receptor 2 (PAR-2) pathway. STI indicates soybean trypsin inhibitor; SLIGRL, serine-leucine-isoleucine-glycine-arginine-leucine. Reprinted with permission from Seiberg M. Keratinocyte–melanocyte interactions during melanosome transfer. Pigment Cell Res. 2001;14:236-242. ©2001, Blackwell Publishing.12 250 CUTIS® Highlighting Skin of Color cosmetic usage and needs survey of 100 women among skin types with regard to the pathogenesis of color, 86% of respondents stated that hyperpig- or the effectiveness and treatment of acne, there mentation or dark spots were a major concern.11 are important differences in clinical presentation, This concern is further supported by a study of histologic appearance, and sequelae.19 Physicians 2000 blacks by Halder et al,7 who found that 37% should be aware of these differences because they of patients were concerned about pigmentation. impact acne treatment protocols. In contrast with comedonal acne in white A Potential New Therapy for skin, which is defined as noninflammatory, Pigmentary Disorders comedone biopsy specimens from black subjects Potential new therapies for pigmentary disor- showed significant inflammation with infiltrates ders are being studied. One novel mechanism of polymorphonuclear leukocytes. Papular and for maintaining normal skin tone and possibly pustular lesions displayed inflammatory infiltrates preventing dyschromias may reside in the eluci- that extended beyond the actual acne lesion.20 dation of the PAR-2 pathway (Figure 1). PAR-2 Inflammation in these comedonal lesions, as well is a receptor expressed on keratinocytes but not as the marked inflammation present in inflam- on melanocytes and thus may regulate pigmen- matory lesions, may explain the propensity for tation via keratinocyte-melanocyte interactions. individuals of color to develop PIH as a sequela PAR-2 activation is involved in cell growth, of acne.21 The Skin of Color Center in New differentiation, and inflammatory processes.13 York City conducted a survey of 313 patients Two soy proteins, soybean trypsin inhibitor and of color with acne vulgaris. More than 50% of Bowman-Birk inhibitor, have been shown to respondents had PIH that lasted an average of regulate the PAR-2 pathway and partially inhibit 4 months, which often was longer than the pigmentation.13 In vitro studies have demon- actual acne lesions lasted; the PIH was noted strated that treatment with these soy proteins to be psychologically and cosmetically disturbing can reduce UV-induced pigment deposition by to the patients.21 PIH is frequently the present- reducing keratinocyte phagocytosis of melanin ing complaint of individuals of color with acne, from melanocytes.14 many of whom request a lightening agent to Pierard and colleagues15 studied the effect of treat the dark marks (Figure 2). These patients stabilized whole soy extracts in white women with find that the dark marks are more distressing a variety of hyperpigmentation disorders. A greater than the acne lesions. It is important to be than 25% improvement in hyperpigmentation was aware of the impact of PIH on patients of noted and was most evident in solar lentigines color and to treat both the acne lesions and and melasma. Additional studies involving indi- the PIH. viduals with skin of color will be needed. The recommendations of the Global Alliance to Improve Outcomes in Acne noted that acne Postinflammatory Hyperpigmentation treatment should target as many pathogenic fac- and Acne tors as possible.22 Hence, the mainstays of acne Postinflammatory
Load more

Recommended publications
  • Assessment of Melanocyte-Specific Primary and Memory Autoimmune Responses in Vitiligo- Prone Smyth and Vitiligo-Susceptible, Non-Expressing Brown Line Chickens
    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 8-2018 Assessment of Melanocyte-Specific rP imary and Memory Autoimmune Responses in Vitiligo-Prone Smyth and Vitiligo-Susceptible, Non-Expressing Brown Line Chickens Daniel Morales Falcon University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/etd Part of the Cell Biology Commons, and the Immunology of Infectious Disease Commons Recommended Citation Falcon, Daniel Morales, "Assessment of Melanocyte-Specific rP imary and Memory Autoimmune Responses in Vitiligo-Prone Smyth and Vitiligo-Susceptible, Non-Expressing Brown Line Chickens" (2018). Theses and Dissertations. 2912. https://scholarworks.uark.edu/etd/2912 This Dissertation is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. Assessment of Melanocyte-Specific Primary and Memory Autoimmune Responses in Vitiligo- Prone Smyth and Vitiligo-Susceptible, Non-Expressing Brown Line Chickens A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Cell and Molecular Biology by Daniel Morales Falcon University of California, Riverside Bachelor of Science in Biology, 2003 August 2018 University of Arkansas This dissertation is approved for recommendation to the Graduate Council. ____________________________________ Gisela F. Erf, Ph.D. Dissertation Director ____________________________________ ___________________________________ Yuchun Du, Ph.D. David McNabb, Ph.D. Committee Member Committee Member ____________________________________ Suresh Thallapuranam, Ph.D. Committee Member Abstract Vitiligo is an acquired de-pigmentation disorder characterized by the post-natal loss of epidermal melanocytes (pigment-producing cells) resulting in the appearance of white patches in the skin.
    [Show full text]
  • Autoimmune Melanocyte Destruction Is Required for Robust CD8+ Memory T Cell Responses to Mouse Melanoma Katelyn T
    Research article Autoimmune melanocyte destruction is required for robust CD8+ memory T cell responses to mouse melanoma Katelyn T. Byrne,1 Anik L. Côté,1 Peisheng Zhang,1 Shannon M. Steinberg,1 Yanxia Guo,1 Rameeza Allie,1 Weijun Zhang,1 Marc S. Ernstoff,2 Edward J. Usherwood,1 and Mary Jo Turk1,3 1Department of Microbiology and Immunology, Dartmouth Medical School, 2Section of Hematology/Oncology, Department of Medicine, Dartmouth Hitchcock Medical Center, and 3The Norris Cotton Cancer Center, Lebanon, New Hampshire, USA. A link between autoimmunity and improved antitumor immunity has long been recognized, although the exact mechanistic relationship between these two phenomena remains unclear. In the present study we have found that vitiligo, the autoimmune destruction of melanocytes, generates self antigen required for mounting persistent and protective memory CD8+ T cell responses to melanoma. Vitiligo developed in approximately 60% of mice that were depleted of regulatory CD4+ T cells and then subjected to surgical excision of large established B16 melanomas. Mice with vitiligo generated 10-fold larger populations of CD8+ memory T cells specific for shared melanoma/melanocyte antigens. CD8+ T cells in mice with vitiligo acquired phenotypic and functional characteristics of effector memory, suggesting that they were supported by ongoing antigen stimulation. Such responses were not generated in melanocyte-deficient mice, indicating a requirement for melanocyte destruction in maintaining CD8+ T cell immunity to melanoma. Vitiligo-associated memory CD8+ T cells provided durable tumor protection, were capable of mounting a rapid recall response to melanoma, and did not demonstrate phenotypic or functional signs of exhaustion even after many months of exposure to antigen.
    [Show full text]
  • Dermal Fibroblasts Internalize Phosphatidylserine-Exposed Secretory Melanosome Clusters and Apoptotic Melanocytes
    International Journal of Molecular Sciences Article Dermal Fibroblasts Internalize Phosphatidylserine-Exposed Secretory Melanosome Clusters and Apoptotic Melanocytes Hideya Ando 1,*, Satoshi Yoshimoto 1, Moemi Yoshida 1, Nene Shimoda 1, Ryosuke Tadokoro 1, Haruka Kohda 2, Mami Ishikawa 2, Takahito Nishikata 2, Bunpei Katayama 3, Toshiyuki Ozawa 3, Daisuke Tsuruta 3 , Ken-ichi Mizutani 4, Masayuki Yagi 5 and Masamitsu Ichihashi 4,6,7 1 Department of Applied Chemistry and Biotechnology, Okayama University of Science, Okayama 700-0005, Japan; [email protected] (S.Y.); [email protected] (M.Y.); [email protected] (N.S.); [email protected] (R.T.) 2 Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; [email protected] (H.K.); [email protected] (M.I.); [email protected] (T.N.) 3 Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; [email protected] (B.K.); [email protected] (T.O.); [email protected] (D.T.) 4 Laboratory of Stem Cell Biology, Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan; [email protected] (K.M.); [email protected] (M.I.) 5 Rosette Co., Tokyo 140-0004, Japan; [email protected] 6 Anti-Aging Medical Research Center, Doshisha University, Kyoto 610-0394, Japan 7 Arts Ginza Clinic, Tokyo 105-0004, Japan * Correspondence: [email protected]; Tel.: +81-86-256-9726 Received: 28 May 2020; Accepted: 9 August 2020; Published: 12 August 2020 Abstract: Pigmentation in the dermis is known to be caused by melanophages, defined as melanosome-laden macrophages.
    [Show full text]
  • Nomina Histologica Veterinaria, First Edition
    NOMINA HISTOLOGICA VETERINARIA Submitted by the International Committee on Veterinary Histological Nomenclature (ICVHN) to the World Association of Veterinary Anatomists Published on the website of the World Association of Veterinary Anatomists www.wava-amav.org 2017 CONTENTS Introduction i Principles of term construction in N.H.V. iii Cytologia – Cytology 1 Textus epithelialis – Epithelial tissue 10 Textus connectivus – Connective tissue 13 Sanguis et Lympha – Blood and Lymph 17 Textus muscularis – Muscle tissue 19 Textus nervosus – Nerve tissue 20 Splanchnologia – Viscera 23 Systema digestorium – Digestive system 24 Systema respiratorium – Respiratory system 32 Systema urinarium – Urinary system 35 Organa genitalia masculina – Male genital system 38 Organa genitalia feminina – Female genital system 42 Systema endocrinum – Endocrine system 45 Systema cardiovasculare et lymphaticum [Angiologia] – Cardiovascular and lymphatic system 47 Systema nervosum – Nervous system 52 Receptores sensorii et Organa sensuum – Sensory receptors and Sense organs 58 Integumentum – Integument 64 INTRODUCTION The preparations leading to the publication of the present first edition of the Nomina Histologica Veterinaria has a long history spanning more than 50 years. Under the auspices of the World Association of Veterinary Anatomists (W.A.V.A.), the International Committee on Veterinary Anatomical Nomenclature (I.C.V.A.N.) appointed in Giessen, 1965, a Subcommittee on Histology and Embryology which started a working relation with the Subcommittee on Histology of the former International Anatomical Nomenclature Committee. In Mexico City, 1971, this Subcommittee presented a document entitled Nomina Histologica Veterinaria: A Working Draft as a basis for the continued work of the newly-appointed Subcommittee on Histological Nomenclature. This resulted in the editing of the Nomina Histologica Veterinaria: A Working Draft II (Toulouse, 1974), followed by preparations for publication of a Nomina Histologica Veterinaria.
    [Show full text]
  • Diccionario De Siglas Médicas Y Otras Abreviaturas, Epónimos Y Términos Médicos Relacionados Con La Codificación De Las Altas Hospitalarias
    Diccionario de siglas médicas y otras abreviaturas, epónimos y términos médicos relacionados con la codificación de las altas hospitalarias JAVIER YETANO LAGUNA VICENT ALBEROLA CUÑAT COORDINACION EDITORIAL: Agustín RIVERO CUADRADO Rogelio COZAR RUIZ REALIZADO POR: Javier YETANO LAGUNA Vicent ALBEROLA CUÑAT MIEMBROS PERMANENTES DEL COMITÉ EDITORIAL: Jesús TRANCOSO ESTRADA M.ª Dolores del PINO JIMENEZ Paloma FERNANDEZ MUÑOZ Joan Ferrer Riera M.ª Coromoto RODRIGUEZ DEL ROSARIO Paz RODRIGUEZ CUNDIN Fernando ROJO ROLDAN Carmen VILCHEZ PERDIGON Abel FERNANDEZ SIERRA M.ª Antonia VÁREZ PASTRANA Belén BENEITEZ MORALEJO Guillermo RODRIGUEZ MARTINEZ Ana VARA LORENZO Carmen SALIDO CAMPOS Arturo ROMERO GUTIERREZ Isabel DE LA RIVA JIMENEZ Pilar MORI VARA M.ª Gala GUTIERREZ MIRAS L. Javier LIZARRAGA DALLO Yolanda MONTES GARCIA M.ª Isabel MENDIBURU PEREZ Vicent ALBEROLA CUÑAT Adolfo CESTAFE MARTINEZ MIEMBROS ASESORES DEL COMITÉ EDITORIAL: Pedro MOLINA COLL M.ª Teresa DE PEDRO Montserrat LOPEZ HEREDERO Jovita PRINTZ Soledad SAÑUDO GARCIA M.ª Luisa TAMAYO CANILLAS Román GARCIA DE LA INFANTA José DEL RIO MATA Pilar RODRIGUEZ MANZANO Esther VILA RIBAS Elena ESTEBAN BAEZ José Alfonso DELGADO Irene ABAD PEREZ José M.ª JUANCO VAZQUEZ Teresa SOLER ROS José Ramón MENDEZ MONTESINO Javier YETANO LAGUNA Margarita LLORIA BERNACER Eloísa CASADO FERNANDEZ M.ª Mar SENDINO GARCIA Fernando PEÑA RUIZ Eduard GUASP SITJAR SECRETARIA: Esther GRANDE LOPEZ Edita y distribuye: © MINISTERIO DE SANIDAD Y CONSUMO CENTRO DE PUBLICACIONES Paseo del Prado, 18-20 - 28014 Madrid ISBN:
    [Show full text]
  • Exosomes Released by Keratinocytes Modulate Melanocyte Pigmentation
    ARTICLE Received 18 Dec 2014 | Accepted 15 May 2015 | Published 24 Jun 2015 DOI: 10.1038/ncomms8506 OPEN Exosomes released by keratinocytes modulate melanocyte pigmentation Alessandra Lo Cicero1,2,3,Ce´dric Delevoye1,2, Floriane Gilles-Marsens1,2, Damarys Loew4, Florent Dingli4, Christelle Gue´re´5, Nathalie Andre´5, Katell Vie´5, Guillaume van Niel1,2,3 &Grac¸a Raposo1,2,3 Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal proteins. Furthermore, we show that the function of keratinocyte-derived exosomes is phototype-dependent and is modulated by ultraviolet B. In sum, this study uncovers an important physiological function for exosomes in human pigmentation and opens new avenues in our understanding of how pigmentation is regulated by intercellular communication in both healthy and diseased states. 1 Institut Curie, PSL Research University, UMR144, CNRS, F-75248 Paris, France. 2 Structure and Membrane Compartments, Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France. 3 Cell and Tissue Imaging Facility, Infrastructures en Biologie Sante´ et Agronomie (IBiSA), Paris F-75248, France. 4 Institut Curie, Centre de Recherche, Laboratoire de Spectrome´trie de Masse Prote´omique, Paris F-75248, France. 5 Laboratoires Clarins—31 chausse´e Jules Ce´sar, Pontoise 95300, France. Correspondence and requests for materials should be addressed to G.R. (email: [email protected]).
    [Show full text]
  • On the Role of Melanoma-Specific CD8 T-Cell Immunity in Disease
    4754 Vol. 10, 4754–4760, July 15, 2004 Clinical Cancer Research On the Role of Melanoma-Specific CD8؉ T-Cell Immunity in Disease Progression of Advanced-Stage Melanoma Patients Monique van Oijen,1 Adriaan Bins,1 cellular immune response, because the presence of tumor-infil- Sjoerd Elias,2 Johan Sein,2 Pauline Weder,1 trating T lymphocytes in primary melanoma and in melanoma Gijsbert de Gast,2 Henk Mallo,1 Maarten Gallee,3 lymph node metastases are independent positive prognostic fac- 4 1 tors (5, 6). Harm van Tinteren, Ton Schumacher, and In past years, extensive efforts to identify target molecules 1,2 John Haanen for melanoma-reactive T cells have resulted in the identification Divisions of 1Immunology, 2Medical Oncology, 3Oncologic of a large set of melanoma-associated antigens (7). These anti- 4 Diagnostics, and Statistics, The Netherlands Cancer Institute, gens can be classified as melanocyte lineage-specific antigens Amsterdam, the Netherlands (MART-1/Melan-A, tyrosinase, gp100) and antigens derived from genes expressed in testis and a variety of cancers (includ- ABSTRACT ing MAGE-family, NY-ESO-1, PRAME). Melanocyte lineage Cytotoxic T-cell immunity directed against melanoso- antigens are expressed in a large fraction of melanomas, and a mal differentiation antigens is arguably the best-studied and substantial number of epitopes from these antigens that are most prevalent form of tumor-specific T-cell immunity in recognized by cytotoxic T cells have been mapped (8). With the humans. Despite this, the role of T-cell responses directed aid of soluble tetramerized MHC complexes containing these ϩ against melanosomal antigens in disease progression has not epitopes, melanosomal antigen-specific CD8 T cells have been been elucidated.
    [Show full text]
  • Melanocyte Differentiation and Epidermal Pigmentation Is Regulated by Polarity Proteins
    bioRxiv preprint doi: https://doi.org/10.1101/2020.04.20.051722; this version posted April 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Melanocyte differentiation and epidermal pigmentation is regulated by polarity proteins Sina K. Knapp1,2 and Sandra Iden1,2,3* 1Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany 2Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany 3Cell and Developmental Biology, Saarland University, Faculty of Medicine, Homburg/Saar, Germany *correspondence: [email protected], Cell and Developmental Biology, Saarland University, Faculty of Medicine, Kirrberger Str., Building 61.4, 66421 Homburg/Saar, Germany ABSTRACT Pigmentation serves various purposes such as protection, camouflage, or attraction. In the skin epidermis, melanocytes react to certain environmental signals with melanin production and release, thereby ensuring photo-protection. For this, melanocytes acquire a highly polarized and dendritic architecture that facilitates interactions with surrounding keratinocytes and melanin transfer. How the morphology and function of these neural crest-derived cells is regulated remains poorly understood. Here, using mouse genetics and primary cell cultures, we show that conserved proteins of the mammalian Par3-aPKC polarity complex are required for epidermal pigmentation. Melanocyte-specific deletion of Par3 in mice caused skin hypopigmentation, reduced expression of components of the melanin synthesis pathway, and altered dendritic morphology. Mechanistically, Par3 was necessary downstream of -melanocyte stimulating hormone (-MSH) to elicit melanin production.
    [Show full text]
  • Melanocyte-Keratinocyte Interactions in Vivo: the Fate of Melanosomes
    YALE JOURNAL OF BIOLOGY AND MEDICINE 46, 384-396 (1973) Melanocyte-Keratinocyte Interactions in Vivo: The Fate of Melanosomes. K. WOLFF Department of Dermatology I, University of Vienna, Aiustria Studies on pigment donation in tissue culture (1-5) indicate that melanosome transfer is a cytophagic process during which a portion of a melanocyte dendrite is pinched off by the epidermal cell so that melanosomes and melanocyte cytoplasm are incorporated into the keratinocyte. At the ultrastructural level, one would ex- rect to see, at this stage, a cluster of melanosomes embedded in a cytoplasmic matrix surrounded by two membranes: one derived from the melanocyte and one belonging to the epidermal cell (Fig. 1). Although such images have not been pub- lished in reports on the electron microscopy of tissue culture (which readily reveals "cytophagocytosis"-phenomena at the light microscope level) they have been ob- served in in vivo specimens of hair bulbs (6), developing fowl feathers (7), and epidermis (Fig. 1). The melanosome complex, however, as it usually appears within keratinocytcs, is limited by only one membrane. It has been suggested (6, 7) that the inner (the melanocytic) membrane is rapidly decomposed but since double membrane-delimited structures occur only in the cell periphery they could equally well represent cross-sectioned dendrites of melanocytes bulging into the cytoplasm of the epidermal cell (Fig. 1). Also, if the matrix of a melanosome complex represents melanocyte cytoplasm it is surprising that it never contains identifiable cytoplasmic residues, such as mitochondria, microfilaments, or similar structures. In heterophagic and autophagic vacuoles such organelles may persist for a considerable time before they are decomposed (8, 9).
    [Show full text]
  • Human Pigmentation Variation: Evolution, Genetic Basis, and Implications for Public Health
    YEARBOOK OF PHYSICAL ANTHROPOLOGY 50:85–105 (2007) Human Pigmentation Variation: Evolution, Genetic Basis, and Implications for Public Health Esteban J. Parra* Department of Anthropology, University of Toronto at Mississauga, Mississauga, ON, Canada L5L 1C6 KEY WORDS pigmentation; evolutionary factors; genes; public health ABSTRACT Pigmentation, which is primarily deter- tic interpretations of human variation can be. It is erro- mined by the amount, the type, and the distribution of neous to extrapolate the patterns of variation observed melanin, shows a remarkable diversity in human popu- in superficial traits such as pigmentation to the rest of lations, and in this sense, it is an atypical trait. Numer- the genome. It is similarly misleading to suggest, based ous genetic studies have indicated that the average pro- on the ‘‘average’’ genomic picture, that variation among portion of genetic variation due to differences among human populations is irrelevant. The study of the genes major continental groups is just 10–15% of the total underlying human pigmentation diversity brings to the genetic variation. In contrast, skin pigmentation shows forefront the mosaic nature of human genetic variation: large differences among continental populations. The our genome is composed of a myriad of segments with reasons for this discrepancy can be traced back primarily different patterns of variation and evolutionary histories. to the strong influence of natural selection, which has 2) Pigmentation can be very useful to understand the shaped the distribution of pigmentation according to a genetic architecture of complex traits. The pigmentation latitudinal gradient. Research during the last 5 years of unexposed areas of the skin (constitutive pigmenta- has substantially increased our understanding of the tion) is relatively unaffected by environmental influences genes involved in normal pigmentation variation in during an individual’s lifetime when compared with human populations.
    [Show full text]
  • Melanin Transfer in the Epidermis: the Pursuit of Skin Pigmentation Control Mechanisms
    International Journal of Molecular Sciences Review Melanin Transfer in the Epidermis: The Pursuit of Skin Pigmentation Control Mechanisms Hugo Moreiras † , Miguel C. Seabra and Duarte C. Barral * iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal; [email protected] (H.M.); [email protected] (M.C.S.) * Correspondence: [email protected]; Tel.: +351-218-803-102 † Present address: The Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland. Abstract: The mechanisms by which the pigment melanin is transferred from melanocytes and processed within keratinocytes to achieve skin pigmentation remain ill-characterized. Nevertheless, several models have emerged in the past decades to explain the transfer process. Here, we review the proposed models for melanin transfer in the skin epidermis, the available evidence supporting each one, and the recent observations in favor of the exo/phagocytosis and shed vesicles models. In order to reconcile the transfer models, we propose that different mechanisms could co-exist to sustain skin pigmentation under different conditions. We also discuss the limited knowledge about melanin processing within keratinocytes. Finally, we pinpoint new questions that ought to be addressed to solve the long-lasting quest for the understanding of how basal skin pigmentation is controlled. This knowledge will allow the emergence of new strategies to treat pigmentary disorders that cause a significant socio-economic burden to patients and healthcare systems worldwide and could also have relevant cosmetic applications. Citation: Moreiras, H.; Seabra, M.C.; Keywords: melanin; melanosome; melanocore; melanocyte; keratinocyte; skin pigmentation; Barral, D.C.
    [Show full text]
  • 26 April 2010 TE Prepublication Page 1 Nomina Generalia General Terms
    26 April 2010 TE PrePublication Page 1 Nomina generalia General terms E1.0.0.0.0.0.1 Modus reproductionis Reproductive mode E1.0.0.0.0.0.2 Reproductio sexualis Sexual reproduction E1.0.0.0.0.0.3 Viviparitas Viviparity E1.0.0.0.0.0.4 Heterogamia Heterogamy E1.0.0.0.0.0.5 Endogamia Endogamy E1.0.0.0.0.0.6 Sequentia reproductionis Reproductive sequence E1.0.0.0.0.0.7 Ovulatio Ovulation E1.0.0.0.0.0.8 Erectio Erection E1.0.0.0.0.0.9 Coitus Coitus; Sexual intercourse E1.0.0.0.0.0.10 Ejaculatio1 Ejaculation E1.0.0.0.0.0.11 Emissio Emission E1.0.0.0.0.0.12 Ejaculatio vera Ejaculation proper E1.0.0.0.0.0.13 Semen Semen; Ejaculate E1.0.0.0.0.0.14 Inseminatio Insemination E1.0.0.0.0.0.15 Fertilisatio Fertilization E1.0.0.0.0.0.16 Fecundatio Fecundation; Impregnation E1.0.0.0.0.0.17 Superfecundatio Superfecundation E1.0.0.0.0.0.18 Superimpregnatio Superimpregnation E1.0.0.0.0.0.19 Superfetatio Superfetation E1.0.0.0.0.0.20 Ontogenesis Ontogeny E1.0.0.0.0.0.21 Ontogenesis praenatalis Prenatal ontogeny E1.0.0.0.0.0.22 Tempus praenatale; Tempus gestationis Prenatal period; Gestation period E1.0.0.0.0.0.23 Vita praenatalis Prenatal life E1.0.0.0.0.0.24 Vita intrauterina Intra-uterine life E1.0.0.0.0.0.25 Embryogenesis2 Embryogenesis; Embryogeny E1.0.0.0.0.0.26 Fetogenesis3 Fetogenesis E1.0.0.0.0.0.27 Tempus natale Birth period E1.0.0.0.0.0.28 Ontogenesis postnatalis Postnatal ontogeny E1.0.0.0.0.0.29 Vita postnatalis Postnatal life E1.0.1.0.0.0.1 Mensurae embryonicae et fetales4 Embryonic and fetal measurements E1.0.1.0.0.0.2 Aetas a fecundatione5 Fertilization
    [Show full text]