Home About us Contact
|
Home About us Contact | ||
|
|
||
Outer Root Sheath (outer + root_sheath)
Selected AbstractsId2, Id3, and Id4 proteins show dynamic changes in expression during vibrissae follicle developmentDEVELOPMENTAL DYNAMICS, Issue 6 2008Nigel L. Hammond Abstract Id proteins are involved in the transcriptional control of many fundamental biological processes, including differentiation and lineage commitment. We studied Id2, Id3, and Id4 protein expression during different stages of rat vibrissa follicle development using immunohistochemistry. Id2 was highly expressed in the cytoplasm of specialized cells in the basal epidermis and outer root sheath during early stages of follicle development. These cells were identified as Merkel cells (MCs) by means of double-immunolabeling with synaptophysin and cytokeratin-20, and persisted in neonatal follicles. Id3 immunofluorescence was characterized by membrane-associated expression in basal epithelial cells of follicles early in development. Subsequently follicle epithelial cells switched to have strong nuclear labeling, also a feature of newly forming dermal papilla cells. Id4 expression was primarily associated with innervation of the developing follicle musculature. These observations illustrate dynamic expression patterns of Id2 and Id3 proteins in developing follicles and specifically link Id2 expression to Merkel cell specification. Developmental Dynamics 237:1653,1661, 2008. © 2008 Wiley-Liss, Inc. [source] Human melanocytes can be isolated, propagated and expanded from plucked anagen hair folliclesEXPERIMENTAL DERMATOLOGY, Issue 6 2010Christina Dieckmann Please cite this paper as: Human melanocytes can be isolated, propagated and expanded from plucked anagen hair follicles. Experimental Dermatology 2010; 19: 543,545. Abstract:, Herein, we report a technically simple method for isolation and culture of human follicular melanocytes based on explant cultures of epilated hair follicles. This technique does not require any surgical intervention and allows the isolation and cultivation of follicular melanocytes from a comparatively small amount of raw material. Generally, 30,60 human anagen hair follicles have been plucked from the scalp of healthy donors and cultivated under low oxygen pressure (5%). After a short period of time cells of various types were growing out from the outer root sheath (ORS) of the hair follicles. Under the selected culture conditions, most of the cells other than melanocytes have been eliminated and a nearly 100% pure population of melanocytes has been achieved, as confirmed by immunohistochemical analyses for melanocyte-specific markers, for example, Tyrosinase-1, S-100 and premelanosomal antigens. These melanocytes derived from the ORS were proliferating for up to 2 months. [source] Reorganization of hair follicles in human skin organ culture induced by cultured human follicle-derived cellsEXPERIMENTAL DERMATOLOGY, Issue 8 2005Walter Krugluger Abstract:, Studies of human hair follicle (HF) induction by follicle-derived cells have been limited due to a lack of suitable test systems. In this study, we established a skin organ culture system which supports HF formation by follicle-derived cells. Long-term skin organ cultures were set up from human retroauricular skin specimens and maintained in culture for up to 8 weeks. In vitro expanded human HF-derived cells from the dermal papilla (DP) and the outer root sheath (ORS) were injected together into the skin specimens and evaluated for their ability to induce reorganization of HFs. Macroscopic analysis of the cultured skin specimens demonstrated the growth of velus-like hair after 4 weeks in culture. Histologic evaluation of the cultured skin specimens after 8 weeks of culture revealed multiple miniaturized HFs with sebaceous glands. In addition, cell clusters of various differentiation stages could be demonstrated in serial sections of the cultured skin specimens. Labeling of HF-derived cells with the fluorescence dye CFDA-1 prior to injection suggested a de novo reorganization of HFs out of the injected cells. In conclusion, the study demonstrated HF formation by HF-derived cells in an in vitro skin organ culture model. [source] Desmocollin 1 expression and desmosomal remodeling during terminal differentiation of human anagen hair follicle: an electron microscopic studyEXPERIMENTAL DERMATOLOGY, Issue 5 2004Elena Donetti Abstract:, The terminal differentiation (TD) program of keratinocytes of the human hair follicle (HF) occurs with specific temporal and spatial features in the various layers of the inner root sheath (IRS) and in the innermost layer of the outer root sheath (companion layer). This process is characterized by complex nuclear and cytoplasmic morphological changes, accompanied by profound modifications in intercellular junctions. As no correlation exists between the structure and the molecular composition of desmosomes during TD of the IRS/companion unit, the aim of our study was to investigate by transmission electron microscopy the remodeling of desmosomes in keratinizing cells of these compartments. By immunogold post embedding technique, we studied in anagen HFs the modulation of the synthesis of desmocollin 1 (Dsc1), a transmembrane glycoprotein specifically synthesized in the IRS and in the companion layer. Dsc1 immunoreactivity was actually confined to these compartments and tended to increase just before the level of TD, particularly in the Henle's layer and in the IRS cuticle. In Huxley's layer, the immunolabeling was patchy and in the companion layer Dsc1 synthesis was detected above the level of keratinization of Huxley's layer. In the whole IRS, concomitantly with TD, there was an abrupt and almost complete disappearance of Dsc1 synthesis. An asymmetric distribution of Dsc1 was noticed (i) between cells at different stages of differentiation and (ii) between cells belonging to layers with different spatial/temporal features of TD. Our results show that the ultrastructural modifications of desmosomes during TD of HF are paralleled by the modulation of the synthesis of desmocollin 1. [source] Expression patterns of MITF during human cutaneous embryogenesis: evidence for bulge epithelial expression and persistence of dermal melanoblastsJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2008Briana C. Gleason Background:, The mechanisms whereby melanocytes populate the epidermis and developing hair follicles during embryogenesis are incompletely understood. Recent evidence implicates an intermediate mesenchymal stage in this evolutionary process in which HMB-45-positive melanocyte precursors (,melanoblasts') exist both in intradermal as well as intraepithelial and intrafollicular compartments. The melanocyte master transcriptional regulator, microphthalmia transcription factor (MITF), identifies mature melanocytes as well as melanocyte precursor stem cells that reside in the bulge region of the hair follicle. Methods:, To better define the use of MITF expression in the evaluation of melanocyte ontogeny, human embryonic and fetal skin samples (n = 28) at 6,24 weeks gestation were studied immunohistochemically for expression of MITF and Mart-1. Adjacent step sections were evaluated to correlate staining patterns with cell localization in the intraepidermal, intrafollicular and intradermal compartments. Results:, At 6,8 weeks, MITF and Mart-1-positive cells were primarily intradermal with only rare positive cells in the epidermis. By 12,13 weeks, most of these cells had migrated into the epidermis, predominantly the suprabasal layers. Between 15,17 weeks, these cells localized to the basal layer and colonized developing hair follicles. Rare intradermal MITF and Mart-1 positive cells were found as late as week 20. At 18,24 weeks, MITF and Mart-1 positive cells were identified in the outer root sheath, bulge, and follicular bulge epithelium, in addition to the epidermis. Unexpectedly, weak but diffuse nuclear MITF expression was also present in the keratinocytes of the bulge area. Conclusions:, The in situ migratory fate of MITF/Mart-1-expressing cells in fetal skin involves a well-defined progression from intradermal to intraepidermal to intrafollicular localization. Occasional intradermal melanocytes may persist after the intraepithelial stages are completed, a finding of potential significance to melanocytic proliferations that may arise de novo within the dermis. Because MITF may play a role in stem cell maintenance, the presence of MITF in bulge epithelial cells suggests that it may be a novel marker for follicular stem cells of both epithelial and melanocytic lineage. [source] p63 expression in normal human epidermis and epidermal appendages and their tumorsJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2003Miki Tsujita-Kyutoku Background:, p63, a member of the p53 gene family, is expressed in basal cells of several different organs. Methods:, The immunoreactivity of p63 was examined in normal human epidermis and epidermal appendages and their tumors, and compared with proliferative activity as evaluated by Ki-67. Results:, In normal skin, p63 expression was seen in basal/suprabasal cells of the epidermis, outer root sheath and hair matrix cells of the hair follicle, seboblast situated in the outermost layer of sebaceous glands, and outer layer cells of the ductal portion and myoepithelial cells of the secretory portion of the sweat glands. p63 expression was confined to the cells forming a continuous basal rim along the normal epithelial structure. In tumors, p63 expression resembled that in normal tissue in that tumor components originating from p63-positive cells were constantly positive for p63. In normal and tumor tissues, not all p63-positive cells were positive for Ki-67. Conclusions:, p63 expression may be a marker of basal/progenitor cells in tumors of epidermis and epidermal appendages, and may be a diagnostic marker of these tumors. [source] Expression of the basal cell adhesion molecule (B-CAM) in normal and diseased human skinJOURNAL OF CUTANEOUS PATHOLOGY, Issue 3 2000Thi-Mai Bernemann The basal cell adhesion molecule (B-CAM) is a 90-kD cell surface glycoprotein with a characteristic immunoglobulin domain structure. The pattern of B-CAM expression in cultured cells suggests that the molecule is associated with a substrate-adherent growth pattern in some lineages. We investigated the expression of B-CAM in normal and diseased human epidermis by means of immunohistochemistry employing a single batch of high-titer mouse monoclonal antibody G253. Snap-frozen biopsy material from normal skin (n=8), psoriasis (n=5), contact dermatitis (n=6), basal cell carcinoma (n=5) and fetal skin (n=6) was studied. In normal human skin, B-CAM was found in varying degrees throughout the epidermis with a preference for suprabasal expression, hair follicles were regularly of a B-CAM-positive phenotype. There were no qualitative differences with regard to the B-CAM expression pattern in normal skin in comparison to psoriasis and contact dermatitis. In contrast, fetal skin (15th to 18th week of gestation) was characterized by B-CAM-positive cells in the basal layer of the epidermis as well as in the outer root sheath of hair follicles. Basal cell carcinomas also regularly expressed high levels of B-CAM. A strong B-CAM-positive phenotype can be found in the outer root sheath of hair follicles of adult and fetal human skin as well as in fetal basal keratinocytes. [source] Thyrotropin-releasing hormone and oestrogen differentially regulate prolactin and prolactin receptor expression in female human skin and hair follicles in vitroBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2010E.A. Langan Summary Background, Human skin and scalp hair follicles are both a nonclassical target and an extrapituitary source of prolactin (PRL), which is a potent hair growth modulator. However, how the expression of PRL and PRL receptor (PRLR) is regulated in human skin is unknown. Objectives, To investigate whether two key stimulators of pituitary PRL secretion, thyrotropin-releasing hormone (TRH) and oestrogen, also regulate cutaneous PRL and PRLR expression. Methods, Female scalp skin and/or microdissected hair follicles were treated for 6 days in serum-free organ culture with oestrogen (100 nmol L,1), TRH (1,10 ng mL,1, 3,30 nm) or vehicle control. Quantitative immunohistomorphometry of skin and hair follicle sections was complemented with quantitative polymerase chain reaction for PRL and PRLR in cultured hair follicles and/or female human outer root sheath (ORS) keratinocytes. Results, Oestrogen treatment significantly upregulated PRL and PRLR immunoreactivity in selected skin and hair follicle compartments, at the gene and protein level (P < 0·05). TRH significantly increased PRL immunoreactivity and transcription in hair follicles (P < 0·05); however, while it also increased PRLR transcription in hair follicles, it downregulated PRLR immunoreactivity in the hair follicle ORS (P < 0·05). Conclusions, Our pilot study shows that two key endocrine controls of pituitary PRL secretion, oestrogen and TRH, also regulate PRL and PRLR expression in human skin. This provides novel insights into the regulation of extrapituitary PRL and PRLR expression, and invites exploration of oestrogen and TRH as novel therapeutic agents in the management of skin and hair diseases characterized by aberrant PRLR-mediated signalling. [source] The neuroepithelial stem cell protein nestin is a marker of the companion cell layer of the adult and developing human hair follicleBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2009D. Krahl Summary Background, The interface between the inner root sheath (IRS) and the outer root sheath (ORS) represents a slippage plane for the hair shaft to evolve from the pilar canal to the skin surface. Interposed between the IRS and ORS is a single cell layer which is believed to represent the angle point of that slippage plane, termed the companion cell layer (CCL). The CCL is cited in most of the literature as part of the ORS. Objectives, To describe the expression pattern of nestin, a neuroepithelial stem cell protein, in the adult and developing human hair follicle. Methods, Immunohistochemical evaluation with a monoclonal antibody against nestin was performed using standard techniques. Results Nestin is selectively expressed in the CCL of the adult anagen and late stage fetal hair follicles. Early stages of hair follicle development are negative for nestin expression. Conclusions, The selective demarcation of the CCL by nestin highlights the unique feature of this follicular cell layer and raises the question of whether the CCL should not be better conceptualized as a part of the IRS rather than the ORS. The results of the present study, together with published ultrastructural data, also suggest that the slippage plane for the evolving hair shaft may be located at the interface between the CCL and the ORS. [source] Stem cell markers (cytokeratin 15, CD34 and nestin) in primary scarring and nonscarring alopeciaBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2009M.P. Hoang Summary Background, Although the pathogenesis of most primary scarring alopecias is poorly understood, recent studies implicate the bulge region as a possible target. Objectives, To corroborate these results, we ascertained involvement of follicular bulge stem cells using a panel of antibodies that putatively targeted the same. Methods, Antibodies used included anticytokeratin (CK) 15, CD34 and nestin on vertical and horizontal tissue sections of 50 cases of scarring and 34 cases of nonscarring alopecia. Results, Comparing expression of these markers in scarring vs. nonscarring alopecia, CK15 was noted in the follicular bulge region in 23 of 43 (53%) vs. 27 of 27 (100%) cases and in the peripheral layer of the outer root sheath (ORS) (upper two-thirds of the follicle) in 50 of 50 (100%) vs. 34 of 34 (100%) cases; CD34 was noted in the peripheral layer of the ORS (below pilar muscle attachment) in 24 of 35 (69%) vs. 18 of 18 (100%) cases; and nestin was noted in the infundibular region in 18 of 46 (39%) vs. seven of 32 (22%) cases and in the inner aspect of the ORS (below pilar muscle attachment) in eight of 31 (26%) vs. 23 of 23 (100%) cases. Conclusions, Our findings of differential follicular localization of stem cells underscore follicular progenitor cell heterogeneity and suggest the target in scarring alopecia is not merely follicular bulge stem cells but involves stem cells in the inner and outer aspect of the ORS. Enhanced expression of nestin in the infundibular region in scarring alopecia indicates availability of an accessible, in vivo niche of potential utility as an autologous source of stem cells for therapeutic application. [source] Differential expression of nitric oxide synthases in human scalp epidermal and hair follicle pigmentary units: implications for regulation of melanogenesisBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2005H.M. Sowden Summary Background, Nitric oxide (NO) is a ubiquitous gaseous lipophilic molecule generated from the conversion of l -arginine to l -citrulline by the NO synthases (NOSs). Ultraviolet radiation (UVR)-induced NO production appears to stimulate epidermal melanogenesis. However, given their relative protection from UVR, it is unclear whether NO plays a similar role in hair bulb melanocytes. Objectives, We aimed to identify the expression profiles of the NOS isoforms endothelial NOS (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS) and of phosphorylated eNOS and nitrotyrosine within the epidermal and follicular melanin units of normal human haired scalp during the hair growth cycle. Methods, This study employed single and double immunohistochemical and immunofluorescence staining techniques using haired scalp from 10 healthy individuals (six women and four men). Results, Melanocytes in the basal layer of the epidermis expressed eNOS, nNOS and nitrotyrosine. By contrast, melanogenically active melanocytes of the anagen hair bulb were wholly negative for these markers. However, other follicular melanocytes not actively involved in pigment production, including undifferentiated melanocytes located in the outer root sheath and melanocytes surviving the apoptosis-driven hair follicle (HF) regression during catagen/telogen, expressed eNOS, nNOS and nitrotyrosine. While iNOS was only weakly expressed in the basal layer of the human epidermis, it was highly expressed in keratinocytes of the inner root sheath (IRS), where it colocalized with trichohyalin, a differentiation-associated protein of the IRS that requires enzyme-catalysed conversion of arginine to citrulline. Conclusions, The NOS isoforms and nitrotyrosine are differentially expressed in different cutaneous melanocyte subpopulations. Results of this study suggest a possible role for eNOS, nNOS, iNOS and nitrotyrosine in melanocyte biology, particularly with respect to melanogenesis and melanocyte survival during HF regression. Another example of possible NO involvement in HF biology is the postsynthetic modification of trichohyalin in differentiating keratinocytes of the IRS. These results suggest that NO may influence several aspects of HF biology. [source] Aberrantly differentiated cells in benign pilomatrixoma reflect the normal hair follicle: immunohistochemical analysis of Ca2+ -binding S100A2, S100A3 and S100A6 proteinsBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2005K. Kizawa Summary Background, Pilomatrixoma is a common benign cutaneous tumour containing differentiated hair matrix cells. This tumour is mainly composed of basophilic, transitional, shadow and squamoid cells. Although some S100 proteins are expressed in a tissue-specific manner in the hair follicle (e.g. S100A2 in the outer root sheath, S100A3 in the cortex and cuticle, and S100A6 in the inner root sheath), little information is available concerning their distribution in the aberrantly differentiated tissues of pilomatrixoma. Objectives, To characterize the disordered epithelial elements of pilomatrixoma by localizing S100A2, S100A3 and S100A6 proteins. Methods, Immunohistochemistry and dual-immunofluorescence microscopy were performed on 22 pilomatrixoma specimens using antibodies specific to the three proteins. Results, Tissue-specific distribution of the S100 proteins investigated was preserved in the morphologically disordered tumour tissues. Anti-S100A2 antibody stained squamoid cells and putative outer root sheath cells; basophilic and potential hair matrix cells were occasionally stained. S100A3 staining was found in transitional cells and putative cortical cells, and was strong in both dispersed cells and hair-like structures surrounding cells which were presumably cuticular cells. Anti-S100A6 antibody labelled some S100A3-negative transitional cell strands, potentially inner root sheath cells. Conclusions, The epithelial elements of pilomatrixoma can be characterized using S100 proteins as biochemical markers. Our results show that pilomatrixomas retain a certain degree of differentiation indicative of distinct hair-forming cells. [source] A study on plucked hair as a substrate for direct immunofluorescence in pemphigus vulgarisJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 2 2009M Daneshpazhooh Abstract Background, It has recently been demonstrated in a study on 15 patients that plucked hair can be used as a substrate for direct immunofluorescence (DIF) in pemphigus. Objective, Our aim was to assess the sensitivity of DIF on plucked hairs in pemphigus vulgaris (PV) patients with positive DIF of oral mucosa. Methods, One hundred and ten new PV patients were enrolled in the study. They all showed the typical clinical and histological findings as well as positive DIF of the oral mucosa, diagnostic for PV. Approximately 30 hairs were obtained in the same way as for the trichogram. The hairs with their outer root sheaths (ORS) were processed for DIF in order to detect immunoglobulin G and C3. Results, Immunodeposits favouring PV were demonstrated in the ORS of 100 cases showing a sensitivity of 91%. Conclusion, Regarding the relatively high sensitivity of DIF on plucked hair in PV patients with positive oral mucosal DIF in our study, it seems that hair plucking is a suitable alternative to the more invasive techniques of skin or mucosal biopsy for obtaining specimens for DIF in PV. Conflicts of interest None declared [source] | ||||||||||