Article

The Biology of Hair Follicles

Department of Dermatology, University Hospital Eppendorf, University of Hamburg, Germany.
New England Journal of Medicine (Impact Factor: 54.42). 09/1999; 341(7):491-7. DOI: 10.1056/NEJM199908123410706
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Available from: Ralf Paus, Aug 27, 2015
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    • "The DP is a discrete population of specialized dermal fibroblasts found at the base of the hair follicle (Paus and Cotsarelis, 1999), and plays a central role in hair follicle morphogenesis (Jahoda and Reynolds, 2000; Reynolds et al., 1999) and mesenchymal-epithelial interactions (Richardson et al., 2005). DP cells have been the focus of much interest because the DP not only regulates hair follicle development and growth, but is also thought to be a reservoir of multipotent stem cells (Driskell et al., 2011). "
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    ABSTRACT: Crude Panax ginseng has been documented to possess hair growth activity and is widely used to treat alopecia, but the effects of ginsenoside Rg3 on hair growth have not to our knowledge been determined. The aim of the current study was to identify the molecules through which Rg3 stimulates hair growth. The thymidine incorporation for measuring cell proliferation was determined. We used DNA microarray analysis to measure gene expression levels in dermal papilla (DP) cells upon treatment with Rg3. The mRNA and protein expression levels of vascular endothelial growth factor (VEGF) in human DP cells were measured by real-time polymerase chain reaction and immunohistochemistry, respectively. We also used immunohistochemistry assays to detect in vivo changes in VEGF and 3-stemness marker expressions in mouse hair follicles. Reverse transcription polymerase chain reaction showed dose-dependent increases in VEGF mRNA levels on treatment with Rg3. Immunohistochemical analysis showed that expression of VEGF was significantly up-regulated by Rg3 in a dose-dependent manner in human DP cells and in mouse hair follicles. In addition, the CD8 and CD34 were also up-regulated by Rg3 in the mouse hair follicles. It may be concluded that Rg3 might increase hair growth through stimulation of hair follicle stem cells and it has the potential to be used in hair growth products. Copyright © 2013 John Wiley & Sons, Ltd.
    Phytotherapy Research 07/2014; 28(7). DOI:10.1002/ptr.5101 · 2.40 Impact Factor
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    • "Molecular signals regulating cycling of hair follicles in postnatal skin are very close to those found in embryo development [11] [12] [13] [14] [15]. So, we suggested that hair loss in mutant mice may be connected with some alterations in hair follicle development in embryogenesis. "
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    ABSTRACT: In adult skin, hair follicles cyclically self-renew in a manner that recapitulates embryonic hair follicle morphogenesis. The most common pathology of hair in adults is alopecia, which is hair loss to different extent. There are a number of murine models of alopecia including spontaneous mutations. In the present study, we worked with double homozygous we/we wal/wal mice which demonstrate symptoms closely resembling human alopecia. Using whole-mount preparations of epidermis of E18.5 embryos we show that hair follicle defects can be revealed as early as during embryonic morphogenesis in these mutants. The number of hair follicles was reduced almost 1.5-fold in mutant skin. The shape of the early stage small follicles was altered in mutant animals as compared to control ones. Additionally, follicles of mutant embryos were wider at the point of conjunction with interfollicular epidermis. We believe that the mutant mice studied represent a fascinating model to address the problem of hair loss. We demonstrated alterations in the morphogenesis of embryonic hair follicle in we/we wal/wal double homozygous mice developing alopecia postnatally. We suppose that incorrect morphogenesis of hair follicles during embryogenesis is closely related to alopecia in the adult life. Unveiling the mechanisms involved in altered embryogenesis may elucidate the pathogenesis of alopecia.
    BioMed Research International 06/2014; 2014. DOI:10.1155/2014/856978 · 2.71 Impact Factor
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    • ": Graphic representation of a typical hair follicle, depicting the regions allowing for follicle generation and differentiation, together with the dermal papilla and follicle matrix. can be found in the article published by Paus and Cotsarelis [4]. "
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    ABSTRACT: The hair follicle is a skin integument at the boundary between an organism and its immediate environment. The biological role of the human hair follicle has lost some of its ancestral importance. However, an indepth investigation of this miniorgan reveals hidden complexity with huge research potential. An essential consideration when dealing with human research is the awareness of potential harm and thus the absolute need not to harm-a rule aptly qualified by the Latin term "primum non nocere" (first do no harm). The plucked hair shaft offers such advantages. The use of stem cells found in hair follicles cells is gaining momentum in the field of regenerative medicine. Furthermore, current diagnostic and clinical applications of plucked hair follicles include their use as autologous and/or three-dimensional epidermal equivalents, together with their utilization as surrogate tissue in pharmacokinetic and pharmacodynamics studies. Consequently, the use of noninvasive diagnostic procedures on hair follicle shafts, posing as a surrogate molecular model for internal organs in the individual patient for a spectrum of human disease conditions, can possibly become a reality in the near future.
    The Scientific World Journal 10/2013; 2013:620531. DOI:10.1155/2013/620531 · 1.73 Impact Factor
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