Human Hair Follicles (human + hair_follicle)

Distribution by Scientific Domains

Selected Abstracts

Characterization and expression analysis of the hair keratin associated protein KAP26.1

M.A. Rogers
Summary Background, Human hair follicle keratin-associated proteins (KAPs) comprise a large multigene family of proteins thought to be responsible for the bundling of keratin intermediate filaments. Recently, four new KAP family members KAP24.1, KAP25.1, KAP26.1 and KAP27.1 were identified from the genome, but the expression of only one, KAP24.1, was investigated and shown in hair follicles. Objectives, In the current study, the expression of the remaining members of the family were analysed. Methods, Reverse transcriptase-polymerase chain reaction analysis of samples from numerous human organs was used. Results, Only KAP26.1 showed expression, which was limited to the hair follicle. By in situ hybridization and immunohistochemistry using a specific antiserum, KAP26.1 was localized to the differentiated portion of the hair cuticle. Conclusions, As well as KAP24.1 in hair follicles, expression of KAP26.1 was shown and is found in the differentiated part of the hair cuticle. [source]

Reorganization of hair follicles in human skin organ culture induced by cultured human follicle-derived cells

Walter 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 study

Elena 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]

The neuroepithelial stem cell protein nestin is a marker of the companion cell layer of the adult and developing human hair follicle

D. 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]

Androgens and hair growth

Valerie Anne Randall
ABSTRACT:, Hair's importance in human communication means that abnormalities like excess hair in hirsutism or hair loss in alopecia cause psychological distress. Androgens are the main regulator of human hair follicles, changing small vellus follicles producing tiny, virtually invisible hairs into larger intermediate and terminal follicles making bigger, pigmented hairs. The response to androgens varies with the body site as it is specific to the hair follicle itself. Normally around puberty, androgens stimulate axillary and pubic hair in both sexes, plus the beard, etc. in men, while later they may also inhibit scalp hair growth causing androgenetic alopecia. Androgens act within the follicle to alter the mesenchyme,epithelial cell interactions, changing the length of time the hair is growing, the dermal papilla size and dermal papilla cell, keratinocyte and melanocyte activity. Greater understanding of the mechanisms of androgen action in follicles should improve therapies for poorly controlled hair disorders like hirsutism and alopecia. [source]

Interleukin-6 cytokine family member oncostatin M is a hair-follicle-expressed factor with hair growth inhibitory properties

Mei Yu
Abstract:, The activation of receptor complexes containing glycoprotein 130 (gp130) identifies the interleukin (IL)-6 cytokine family. We examined members of this family for their expression and activity in hair follicles. Quantitative polymerase chain reaction using mRNA derived from microdissected, anagen-stage human hair follicles and comparison to non-follicular skin epithelium revealed higher levels of IL-6 (15.5-fold) and oncostatin M (OSM, 3.4-fold) in hair follicles. In contrast, expression of all mRNAs coding for IL-6 cytokine family receptors was reduced. Immunohistology suggested expression of OSM, gp130, leukaemia inhibitory factor receptor (LIFr) and IL-11r in the hair follicle root sheaths and dermal papilla, while IL-11, IL-6r and OSMr were expressed in root sheaths alone. IL-6 was expressed in the dermal papilla while cardiotrophin-1 (CT-1) and LIF were not observed. OSM and to a lesser extent CT-1 exhibited a dose-dependent growth inhibition capacity on human hair follicles in vitro. OSM and CT-1 incubated with agarose beads and injected subcutaneously at 1 ,g per mouse into telogen skin of 65-day-old mice revealed no capacity to induce anagen hair growth. In contrast, injection of 65-day-old mice in which anagen had been induced by hair plucking revealed a moderate hair growth inhibitory capacity for OSM, but no significant effect for CT-1. The data identify OSM as a modulator of hair follicle growth and suggest other family members may also have some degree of hair growth inhibitory effect. In principle, increased expression of some IL-6 cytokine family members in cutaneous inflammation might contribute to the promotion of hair loss. [source]

17,-estradiol induces aromatase activity in intact human anagen hair follicles ex vivo

R. Hoffmann
Abstract: For topical treatment of androgenetic alopecia (AGA) in women, solutions containing either estradiol benzoate, estradiol valerate, 17,- or 17,-estradiol are commercially available in Europe and some studies show an increased anagen and decreased telogen rate after treatment as compared with placebo. At present it is not precisely known how estrogens mediate their beneficial effect on AGA-affected hair follicles. We have shown recently that 17,-estradiol is able to diminish the amount of dihydrotestosterone (DHT) formed by human hair follicles after incubation with testosterone, while increasing the concentration of weaker steroids such as estrogens. Because aromatase is involved in the conversion of testosterone to estrogens and because there is some clinical evidence that aromatase activity may be involved in the pathogenesis of AGA, we addressed the question whether aromatase is expressed in human hair follicles and whether 17,-estradiol is able to modify the aromatase activity. Herewith we were able to demonstrate that intact, microdissected hair follicles from female donors express considerably more aromatase activity than hair follicles from male donors. Using immunohistochemistry, we detected the aromatase mainly in the epithelial parts of the hair follicle and not in the dermal papilla. Furthermore, we show that in comparison to the controls, we noticed in 17,-estradiol-incubated (1 nM) female hair follicles a concentration- and time-dependent increase of aromatase activity (at 24 h: 1 nM = +18%, 100 nM = +25%, 1 M = +57%; 24 h: 1 nM = +18%, 48 h: 1 nM = +25%). In conclusion, our ex vivo experiments suggest that under the influence of 17,-estradiol an increased conversion of testosterone to 17,-estradiol and androstendione to estrone takes place, which might explain the beneficial effects of estrogen treatment of AGA. [source]

In-vitro permeation of drugs into porcine hair follicles: is it quantitatively equivalent to permeation into human hair follicles?

Yakov Frum
It is already well-established that the general permeability properties of porcine skin are close to those of human skin. However, very little is known with respect to drug absorption into hair follicles and the similarities if any between the two types of tissue. The aim of this study was to use the skin sandwich system to quantify follicular drug absorption into porcine hair follicles. To our knowledge, this is the first time that the skin sandwich has been extended to porcine tissue. For this purpose, seven different drugs , estradiol, corticosterone, hydrocortisone, aldosterone, cimetidine, deoxyadenosine and adenosine , exhibiting a wide range of log octanol-water partition coefficients (log Ko/w), but comparable molecular weights, were chosen as candidate solutes. The results showed a parabolic profile with maximal follicular contribution occurring at intermediate log Ko/w values. Linear regression analysis indicated that the follicular contributions in porcine skin correlated well with previously published follicular contributions in human skin (r2 = 0.87). The novelty of this research is that we show that porcine tissue is a good surrogate for modelling human skin permeability within the specific context of quantifying drug absorption into hair follicles. [source]

Temporary hair removal by low fluence photoepilation: Histological study on biopsies and cultured human hair follicles

Guido F. Roosen MSc
Abstract Background and Objectives We have recently shown that repeated low fluence photoepilation (LFP) with intense pulsed light (IPL) leads to effective hair removal, which is fully reversible. Contrary to permanent hair removal treatments, LFP does not induce severe damage to the hair follicle. The purpose of the current study is to investigate the impact of LFP on the structure and the physiology of the hair follicle. Study Design/Materials and Methods Single pulses of IPL with a fluence of 9 J/cm2 and duration of 15 milliseconds were applied to one lower leg of 12 female subjects, followed by taking a single biopsy per person, either immediately, or after 3 or 7 days. Additionally, we present a novel approach to examine the effects of LFP, in which ex vivo hairy human scalp skin was exposed to IPL pulses with the same parameters as above, followed by isolation and culturing of the hair follicles over several days. Samples were examined histologically and morphologically. Results The majority of the cultured follicles that had been exposed to LFP treatment showed a marked treatment effect. The melanin containing part of the hair follicle bulb was the target and a catagen-like transformation was observed demonstrating that hair formation had ceased. The other follicles that had been exposed to LFP showed a less strong or no response. The skin biopsies also revealed that the melanin-rich region of the hair follicle bulb matrix was targeted; other parts of the follicle and the skin remained unaffected. Catagen/telogen hair follicles were visible with unusual melanin clumping, indicating this cycle phase was induced by the IPL treatment. Conclusions Low fluence photoepilation targets the pigmented matrix area of the anagen hair follicle bulb, causing a highly localized but mild trauma that interrupts the hair cycle, induces a catagen-like state and eventually leads to temporary loss of the hair. Lesers Surg. Med. 40:520,528, 2008. 2008 Wiley-Liss, Inc. [source]

A modified method for purifying amelanotic melanocytes from human hair follicles

Hui-Jun MA
ABSTRACT We describe a modified method for establishing long-term pure cultures of amelanotic melanocytes (AMMC) derived from human hair follicles. Normal human corpse scalp (just after death, 1 h) was transected 1 mm below the epidermis, and hair follicles in the remaining dermis were isolated by a two-step enzyme treatment. Hair follicle cell suspensions were prepared by 0.50% trypsin treatment for 30 min and cultured in an optimized melanoblast proliferation nature mitogen medium. Cells attached to the substratum were mostly amelanotic melanocytic in character with small, bipolar shapes in the early stage; only a few keratinocytes and rare fibroblasts were observed. Keratinocytes were easily removed by differential trypsinization. After the third passage, the proliferating cells were all amelanotic melanocytes as confirmed by immunostaining with polyclonal antibodies to ,PEP7h, which recognized the tyrosinase protein located on melanosomes and NKI/beteb, which is a pre-melanosomal antigen against synthetic peptides corresponding to the carboxyl termini of human melanosomal protein GP100. Cultured AMMC were highly positive to L-dopa reactivity after the addition of IBMX to the culture medium for 7 days. Many stage I and II melanosomes and occasional stage III melanosomes without stage IV melanosomes were found in the cytoplasm by transmission electron microscope. This modified technique is potentially more suitable for cultivating amelanotic melanocytes. The availability of pure cultures of hair-follicle amelanotic melanocytes will facilitate investigations of the roles of those cells in migration and differentiation during treatment of vitiligo. [source]