ArticleLiterature Review

The human hair: From anatomy to physiology

Authors:
  • International Hair Research Foundation
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Abstract

Hair is a unique character of mammals and has several functions, from protection of the skin to sexual and social communication. In literature, there are various studies about hair that take into consideration different aspects within many fields of science, including biology, dermatology, cosmetics, forensic sciences, and medicine. We carried out a search of studies published in PubMed up to 2013. In this review, we summarized the principal anatomical and physiological aspects of the different types of human hair, and we considered the clinical significance of the different structures and the distribution of the hair in the human body. This review could be the basis for improvement and progression in the field of hair research.

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... Hair is a derivative of the epidermis which physically is thin, flexible tubes of a dead, fully keratinized cell. Hair from the macrostructural point of view, hair has varied in term the hair length, diameter, colour and cross-sectional shape (Buffoli et al., 2014). Hair serves as many functions in which the main function is to protect the surface of the skin and act as the thermoregulator. ...
... Hair consists of two different structure fibre which is follicle and hair shaft. The hair follicle is said as the living part of the hair that located under the skin while the hair shaft is fully keratinized dead part that can be found above or on the skin surface (Buffoli et al., 2014;Cooper, 2015;Erdoğan, 2017;Murphrey et al., 2020). The hair shaft is the hair that visible on the skin surface. ...
... The cuticle is the outermost layer that is formed by tightly packed scales resemble roof shingles in an overlapping structure. Cuticle cell covers the hair from the root to the tip of the epidermis that also has important protective properties also act as barrier function against physical and chemical insults (Buffoli et al., 2014;Cooper, 2015). Next, the middle layer called cortex which makes up the majority of the hair shaft and the innermost layer is medulla. ...
Article
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Hair loss or alopecia is a common dermatological issue that can affect millions of human population of all ages and both gender, male and female. Frequently, alopecia has been found to be associated with significant adverse effects or reduction of psychological and self-esteem. Consequently, this may lead to psychological problems such as depression and anxiety, thus it may negatively impact the quality of life as well. There are several types of hair loss including androgenetic alopecia (AGA), alopecia areata (AA), alopecia totalis (AT), Alopecia Universalis (AU), cicatricial alopecia (CA), senescent alopecia (SA), traction alopecia (TA) and telogen effluvium. However, this review will focus on the androgenic alopecia only. Androgenic alopecia (AGA) also known as male pattern baldness is referred to as hair loss that often occurs in men after puberty caused by the androgen. In addition, this review will discuss on the hair growth cycles and their mechanism on the androgenic alopecia and lastly the management of androgenic alopecia using plant derivatives and methods used in order to prolong the efficacy of androgenetic alopecia treatment.
... Hence, different normal concentration values (norms) for evaluating toxic concentrations are needed. Norms of elemental concentrations have already been established [33,34]. Ethnicity in Sudan is widely spread and hence no clear limitation on hair composition could be achieved. ...
... Because of its growth process, hair might in addition reveal the biomedical and environment history of the patient [39,40]. Human hair consists mainly of α-keratin [34]. It is thus of consequence that the concentrations of elements in hair be determined with the utmost accuracy. ...
... Normal values (Norms) for the elements were obtained from [32][33][34][35][36]53]. The minimum detection limits (MDLs) were obtained from the X-ray emission analysis. ...
Article
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Many individuals come into contact, at times unawares, with substances that due to concentrations can be classified as environmental pollutants. These substances can have marked adverse health effects on the individual when present in toxic concentration ranges. Excess accumulation of these elements can be determined in hair since hair does not have an excretion point. To investigate any such occurrences, scalp-hair samples were collected from male and female student volunteers (n = 183), aged between 20 and 23 years. These students were attending the Sudan University of Technology, but originated from four regions in Sudan. Elemental concentrations were quantitatively determined by X-ray emission. The study shows that the different inter-region and inter-gender results revealed alarming health effects of environmental pollution.
... Hair is a unique mammalian feature as it covers almost all the skin surface with the exception of the sole of the foot, palm of the hand, buccal of the lip, and portions of sexual organs. Additionally, it is possible to note that human hair growth is modified from unseen tiny and colorless on most of the body surface, while longer, thicker, and heavily pigmented in other areas, such as the scalp, eyelashes, and eyebrows, if the distribution of hair in different body areas is considered [219]. ...
... Specifically, eyebrows and eyelashes stop particles in damaging the eyes, while scalp hair guards the head and neck against sunlight, cold, and physical damage. Besides, considering the psychological consequences on the quality of life in hair disorders, such as hirsutism and hair loss or alopecia, it functions important roles in sexual and social communication [219]. ...
Chapter
The concept of beauty and cosmetics is as ancient as mankind and civilization where everyone is obsessed with looking charming and young. A cosmetic is defined by the US Food and Drug Administration as the preparation used for cleaning, perfuming, and improving the appearance of the human body. Plants have emerged as the best source of cosmetic ingredients that meet the characteristics of efficiency and safety, thus increasingly replacing synthetic ingredients. Accordingly, there is a growing demand for naturally based cosmetics worldwide and an ever-growing interest in understanding their molecular and mechanistic aspects. In this chapter, we discussed the role of plants in cosmetology and skin care and how the various chemical structures exert biological activities on the skin of human.
... Although the mouse is the most commonly used animal model for research on human HF development, the classification of hair types in human has been implemented in different ways, mainly depending on the body parts (e.g., scalp, beard, chest, pubic, and axillary hair) with scalp hair being the most studied hair type (Duverger and Morasso, 2009;Buffoli et al., 2014). Nonetheless, similarities could still be explored between pig and human scalp hair. ...
... Although the hair density of human scalp hair (292/cm 2 ) was much higher than pig head (46-53/cm 2 ), the trend of a higher head HF density than other body parts was shared by pig and human (Table 2 and Figure 1D). Unlike mice, which exhibit pelage with synchronous growth patterns, the asynchronous hair growth in different human body parts (Buffoli et al., 2014) leads to more growth of the HFs on the scalp and face than on the arms and legs (Seago and Ebling, 1985;Pagnoni et al., 1994). Thus, based on our results which showed similarity of hair type and growth pattern between pig and human, it could be speculated that the pig hair growth is also asynchronous (Koch et al., 2020). ...
Article
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The pig is an increasingly popular biomedical model, but only a few in depth data exist on its studies in hair follicle (HF) morphogenesis and development. Hence, the objective of this study was to identify the suitability of the pig as an animal model for human hair research. We performed a classification of pig HF morphogenesis stages and hair types. All four different hair types sampled from 17 different body parts in pig were similar to those of human. The Guard_2 sub-type was more similar to type II human scalp hair while Guard_1, Awl, Auchene, and Zigzag were similar to type I scalp hair. Based on morphological observation and marker gene expression of HF at 11 different embryonic days and six postnatal days, we classified pig HF morphogenesis development from E41 to P45 into three main periods – induction (E37–E41), organogenesis (E41–E85), and cytodifferentiation (>E85). Furthermore, we demonstrated that human and pig share high similarities in HF morphogenesis occurrence time (early/mid gestational) and marker gene expression patterns. Our findings will facilitate the study of human follicle morphogenesis and research on complex hair diseases and offer researchers a suitable model for human hair research.
... In traditional Chinese medicine, the dried whole plant of C. discolor has been used for anti-inflammatory, antibacterial, and antitoxic purposes. 2,3) During the course of our studies on the characteristics of bioactive constituents from natural sources that are useful for cosmetics, such as melanogenesis inhibitory, [4][5][6][7][8][9][10][11][12][13] collagen synthesis-promoting, collagenase and hyaluronidase inhibitory, [14][15][16][17][18][19] and 5α-reductase inhibitory 20) activities, we previously found that the methanol extract of the underground part of C. discolor and its constituents showed hair-restoring activity in C3H mice and promoted blood flow in the dorsal skin of rats. 3) Herein, to continue our study of the bioactive constituents from this plant material used for cosmetics, we show that the methanol extract exhibits proliferative activity on human hair follicle dermal papilla cells (HFDPC). ...
... where A is the absorbance at 450 nm (650 nm for the test sample) and B is the absorbance at 450 nm (650 nm for the control). Assay for Testosterone 5α-Reductase Inhibitory Activity The experiment was performed in accordance with previously reported methods 20,45,54,55) with slight modifications. In brief, the assay was performed in 48-well microplates (Sumitomo Bakelite Co., Ltd., Tokyo, Japan). ...
Article
A methanol extract from the underground part of Calanthe discolor Lindl. (Orchidaceae) demonstrated significant proliferative activity on human hair follicle dermal papilla cells (HFDPC, % of control: 120.8 ± 0.2%) at 100 µg/mL against HFDPC. Through bioassay-guided separation of the extract, a new indole glycoside named 6′-O-β-D-apiofuranosylindican (1) was isolated along with six known compounds (2–7) including three indole glycosides. The stereostructure of 1 was elucidated based on its spectroscopic properties and chemical characteristics. Among the isolates, 1 (110.0 ± 1.0%), glucoindican (3, 123.9 ± 6.8%), and calanthoside (4, 158.6 ± 7.1%) showed significant proliferative activity at 100 µM. Furthermore, the active indole glycosides (1, 3, and 4) upregulated the expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor-7 (FGF-7) mRNA and protein in HFDPC, which could be the mechanism of their proliferative activity. Fullsize Image
... It varies according to the ethnic group and among individuals. With the exception of some areas such as foot soles, hand palms, buccal surface of the lips and parts of the external genitalia, mammalian skin generates hair almost all over the body surface [70]. Hair is comprised of two parts: the follicle which is in the skin and the shaft which can be seen on the surface of the body. ...
... Hair begins from the epidermis surface and extends to various depths in the skin according to the type of hair. Thick, long and pigmented hair (terminal hair) is produced from hair follicles that extend into the deep epidermis, while thin, short and light-coloured hair (vellus hair) is produced from follicles which extend into the upper epidermis [70,71]. ...
Article
The poor aqueous solubility of many approved drugs and most new chemical entities poses a challenge to drug delivery scientists working in academic and industrial labs. Despite the high pharmacological activity these drugs may have, their limited water solubility leads to poor absorption and consequently to sub-therapeutic drug concentrations in target tissues. The formulation of drug nanocrystals (NCs) has emerged as one the most promising approaches for increasing the biopharmaceutical performance of hydrophobic drugs. Initially aimed at increasing the absorption of drugs administered orally, NCs have been increasingly utilised to allow drug delivery via multiple routes, namely, parenteral injections, transdermal, ocular, intranasal, and pulmonary. This review aims to describe the recent progress in the field and demonstrate how the NCs technology enabled the delivery of hydrophobic drugs through multiple administration routes.
... Immunofluorescence observations were performed and recorded with a Leica fluorescence microscope (Leica Biosystems, Nussloch, Germany). Mx cells were defined as the lowermost portion of the HF epithelial cells below the top of the DP 70 . For quantitative analyses, the number of positive cells was counted in the Mx, ORS, and DP areas in the bulb and the basal and suprabasal layers in the bulge using ImageJ software (National Institutes of Health, Bethesda, MD, USA) with blinding regarding the experimental group. ...
Article
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The maintenance of genetic integrity is critical for stem cells to ensure homeostasis and regeneration. Little is known about how adult stem cells respond to irreversible DNA damage, resulting in loss of regeneration in humans. Here, we establish a permanent regeneration loss model using cycling human hair follicles treated with alkylating agents: busulfan followed by cyclophosphamide. We uncover the underlying mechanisms by which hair follicle stem cells (HFSCs) lose their pool. In contrast to immediate destructive changes in rapidly proliferating hair matrix cells, quiescent HFSCs show unexpected massive proliferation after busulfan and then undergo large-scale apoptosis following cyclophosphamide. HFSC proliferation is activated through PI3K/Akt pathway, and depletion is driven by p53/p38-induced cell death. RNA-seq analysis shows that HFSCs experience mitotic catastrophe with G2/M checkpoint activation. Our findings indicate that priming mobilization causes stem cells to lose their resistance to DNA damage, resulting in permanent loss of regeneration after alkylating chemotherapy.
... Pubic hair is anatomically structured by cortex and cuticle cells, hair follicle and sebaceous glands. It is the heavier, longer hair that develops during puberty 30 . These structures form a microenvironment of their own, which supports the establishment of an unique and characteristic microbiota in the pubic hair. ...
Article
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Genital hair is one of the secondary sexual traits that marks the beginning of puberty; its removal has been part of human culture since ancient times. This practice may lead to modifications in vaginal microbiome with potential repercussions on skin health and balance. We conducted a narrative review with the purpose of describing normal skin microbiota, its impact under microenvironment changes and genital hair removal. Menses, pathological conditions and pubic hair removal may alter vaginal microbiota, being the latter of special relevance giving the risk of hair microtrauma, irritations and potential spread of infectious agents.
... Human hair is a precious physical feature of the human body, of strong psychological and social importance, especially for women. Their biological functions consist of protection of the skin and thermic regulation (Buffoli et al., 2014). Specifically, scalp hair protects head skin from sunlight rays, avoids the thermic dispersion, owns sensory properties and plays a key role in social communication. ...
Article
During aging, usually graying of the hair occurs as a result of oxidative stress. Driven by social acceptance and self-perception of the exterior appearance, both men and women rely on hair dyeing products, in order to mask the graying hair. At the same time, a frequent use of synthetic products and treatment can damage the hair shaft; for this reason, this study aimed to evaluate the morphological effect of the herbal dye derived from Lawsonia inermis (henna), on hair. Dyed hairs were evaluated by means of SEM. Subsequently, they were compared, qualitatively and quantitatively, with undyed hairs. Results showed a positive impact on the cuticula pattern and on the diameters of the examined samples, after henna application. Different results, about the degree and the type of morphological changes occurring on pigmented hairs, may depend on the phenotype and on the health condition of hair, before dye treatment.
... Der Haarfollikel ist eine zylindrische epitheliale Struktur, die in die Dermis und das subkutane Fett hineinwächst und sich an der Basis in den Haarbulbus erweitert, der die Hautpapillen, die mesenchymalen Ursprungs sind, umgibt (Buffoli et al. 2014). Das gewölbte Areal des Haarfollikels ist eine Struktur im äußeren Wurzelblatt auf Niveau des Ansatzes des M. arrector pili (arrector pili muscle -APM) (über dem Ansatz des APM und unter der Talgdrüse) Ohyama et al. 2006), wo Stammzellen zugängliche, undifferenzierte, hochproliferierte, multipotente Stammzellen freisetzen. ...
Chapter
Der Alterungsprozess der differenzierten Gewebeschichten wird bestimmt durch: Intrinsische Faktoren, Extrinsische Faktoren, Alterungsprozesse der Zelle, Zellbiologie/ Zellpathologie, Zellregeneration, Alterungsprozesse der Gewebeschichten, Haut Histologie, Mikrobiologie, Physiologie und Faltenqualität (dynamische/statische Falten), Fett (Reduktion in den einzelnen Schichten und Fettkörpern), Bindegewebe (retaining ligaments, Halteapparat, Vaskularisierung), Muskeln (Atrophie/Hypertrophie), Knochenalterung und -reduktionszonen. Inhalt: Histologische Merkmale der Hautalterung, Hautalterungstypen nach Kerscher et al., Mikrobiologie und Physiologie der Altershaut, In-vivo-Messverfahren zur Evaluation von Hautqualität und -physiologie, Faltenqualität, Faltentypen, Objektivierung und Evaluation der Faltenausprägung
... Hair follicles (HFs) are epidermal invaginations in the dermis that generate hair shafts, present almost all over mammals' body surfaces with some exceptions (e.g. sole of the foot, palm of the hand) [131]. HFs are mini-organs that form during embryonic development and undergo continuous dynamic cycles during life consisting of three phases: anagen (i.e. ...
Article
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Tissue engineering (TE) is a multidisciplinary research field aiming at the regeneration, restoration, or replacement of damaged tissues and organs. Classical TE approaches combine scaffolds, cells and soluble factors to fabricate constructs mimicking the native tissue to be regenerated. However, to date, limited success in clinical translations has been achieved by classical TE approaches, due to the lack of satisfactory bio-morphological and bio-functional features of the obtained constructs. Developmental TE has emerged as a novel TE paradigm to obtain tissues and organs with correct bio-morphology and bio-functionality by mimicking the morphogenetic processes leading to the tissue/organ generation in the embryo. Ectodermal appendages, for instance, develop in vivo by sequential interactions between epithelium and mesenchyme, in a process known as secondary induction. A fine artificial replication of these complex interactions can potentially lead to the fabrication of the tissues/organs to be regenerated. Successful developmental TE applications have been reported, in vitro and in vivo, for ectodermal appendages such as teeth, hair follicles and glands. Developmental TE strategies require an accurate selection of cell sources, scaffolds and cell culture configurations to allow for the correct replication of the in vivo morphogenetic cues. Here, we describe and discuss the emergence of this TE paradigm by reviewing the achievements obtained so far in developmental TE 3D scaffolds for teeth, hair follicles, and salivary and lacrimal glands, with particular focus on the selection of biomaterials and cell culture configurations.
... Each follicle contains a permanent distal portion and 'transient' proximal portion, which grows and involutes with each hair cycle, producing a hair shaft. The permanent portion of the follicle contains the sebaceous gland, arrector pili muscle insertion, upper hair shaft, and the follicular stem cell niche located in the 'bulge' [31]. ...
Article
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The Primary Scarring Alopecias are characterised by the irreversible destruction and fibrosis of hair follicles, leading to permanent and often disfiguring loss of hair. The pathophysiology of these diseases is not well understood. However, follicular-fibrosis and loss of the stem-cell niche appears to be a common theme. This review explores the pathogenesis of primary scarring alopecias, asking what happens to the stem cells of the hair follicle and how they may contribute to the progression of these diseases. Bulge-resident cells are lost (leading to loss of capacity for hair growth) from the follicle either by inflammatory-mediate apoptosis or through epigenetic reprogramming to assume a mesenchymal-like identity. What proportion of bulge cells is lost to which process is unknown and probably differs depending on the individual PCA and its specific inflammatory cell infiltrate. The formation of fibroblast-like cells from follicular stem cells may also mean that the cells of the bulge have a direct role in the pathogenesis. The identification of specific cells involved in the pathogenesis of these diseases could provide unique diagnostic and therapeutic opportunities to prevent disease progression by preventing EMT and specific pro-fibrotic signals.
... The existence of heteroplasmic individuals and the limited knowledge about both the mechanism and the rate of heteroplasmy can be issues raised in an attempt to exclude mtDNA evidence from forensic investigations. Heteroplasmy at one nucleotide position is more frequently observed in hair samples, mainly due to genetic drift and to bottlenecks which occur due to the hair follicle's semiclonal nature (Budowle et al., 2003;Buffoli et al., 2013;Paus, 1998;Rogers, 2004). Hence, if an evidentiary hair sample contains one of the two heteroplasmic lineages that are observed in a reference sample, or vice versa, then the interpretation of exclusion may be incorrect. ...
Article
Full-text available
Mitochondrial DNA (mtDNA) presents several characteristics useful for forensic studies, especially related to the lack of recombination, to a high copy number, and to matrilineal inheritance. mtDNA typing based on sequences of the control region or full genomic sequences analysis is used to analyze a variety of forensic samples such as old bones, teeth and hair, as well as other biological samples where the DNA content is low. Evaluation and reporting of the results requires careful consideration of biological issues as well as other issues such as nomenclature and reference population databases. In this work we review mitochondrial DNA profiling methods used for human identification and present their use in the main cases of humanidentification focusing on the most relevant issues for forensics.
... Due to the high proportion of telogen hair in body hair, they are considered to be unsuitable to determine the time frame within the consumption was monitored. Although, in general, the time period correlates with the hair length, there are significant differences in the proportions anagen/ telogen hair and in growth rate from the different various anatomical sites, and dependent on race, sex, age and state of health [11,[13][14][15]. Pianta et al. suggested the following formula to determine the maximum value of the time window, depending on the average of telogen hair [6]: time window = hair length/growth rate  ((1-telogen%)/100. ...
... The high mechanical strength of hair is derived from the alphakeratin intermediate filaments and keratin associated proteins (KAP; high/ultrahigh cysteine and high glycine/tyrosine) through an extensive disulphide bond cross-linking and hydrophobic interactions in the cortex. 29 The hair strands were evaluated for their break load and mean diameter, which are extremely important parameters, since they are associated with the resistance of the hair fibre. 22 The tensile strength, calculated by the ratio between break load and the cross-sectional area of the fibre, is a good indicator of the resistance of hair fibre to possible fractures and/or ruptures. ...
Article
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Background: Sensory and structural characteristics of hair can be modified by chemical and physical treatments, as dyeing, brushing, but also by external factors, as sunlight radiation. However, quantitative data relating damage to the degree of hair curliness and treatments are missing. Objective: To evaluate the effect of chemical and physical treatments on different types of hair. Methods: In this study, we compared the effects of bleaching/dyeing, thioglycolate-based straightening, brushing/flat iron and UVA/Vis radiation on different types of hair: Caucasian (straight dark brown, straight blond, wavy dark brown and curly dark brown) and Afro-ethnic hair. Results: Bleaching/dyeing and UVA/Vis radiation increased combing work of Afro-ethnic hair tresses, indicating damage to the cuticle scales, which was confirmed by SEM images. Further, bleaching/dyeing caused wear on cuticles with high protein loss and reduction on the tryptophan content, independently of the hair curliness, which characterizes those procedures as very aggressive to hair structure. Straightening using ammonium thioglycolate, due to the oxidative treatment evolved, caused significant color fading in brown/black tresses, while UVA/Vis radiation affected the color of only blond hair tresses since they are poor in eumelanin, the photoprotective and photostable melanin molecule. Conclusion: The combination of analytical and image techniques contributed to understanding how the hair shape is related to the type of damage caused by several chemical and physical treatments. These findings contribute to the development of safety cosmetics that insure the beauty of curly hair, both Caucasian and Afro-ethnic hair. This article is protected by copyright. All rights reserved.
... Hair bleaching and permanent dyeing consist in aggressive chemical treatments during which the scales that form the cuticle of the hair shaft are opened by the action of the alkaline solution containing NH 4 OH. This step lets the other oxidant compounds (such as H 2 O 2 ) inside, where they can react with the melanin that mostly resides within the hair cortex (20). H 2 O 2 is responsible for the oxidative degradation of melanin and the increased hair porosity due to sulfur oxidation and removal (21,22); this can also lead to a loss of several bound xenobiotics (including EtG) and a consequential decrease in their hair content (7,23). ...
Article
Hair analysis is an important and reliable resource for the assessment of alcohol or drug abstinence in both clinical and forensic toxicology. Recently, it has been demonstrated that hair oxidative cosmetic treatments lead to the reduction of incorporated xenobiotics in hair, such as ethyl glucuronide (EtG), a marker of alcohol abuse, and the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a degradation product of melanin. The aim of the present study was to investigate PTCA trends in a large number of samples in order to evaluate the reliability of this biomarker in recognizing previous cosmetic treatment in forensic analyses. Therefore, a single-step extraction followed by an HPLC-MS-MS method was established and validated for the simultaneous determination of EtG and PTCA This method was applied to 1219 scalp hair samples from two groups, namely self-reported untreated and in vivo treated hair, exhibiting a concentration range of 6.7-440.0 pg/mg for EtG (mean 26.8 pg/mg, median 14.6 pg/mg) and 0.009-49.8 ng/mg for PTCA (mean 0.66 ng/mg, median 0.02 ng/mg). The PTCA content was significantly different among the two experimental groups, with the in vivo treated group showing significantly higher levels of PTCA than the untreated group. Finally, an in vitro bleaching was performed and the results confirmed that a strong hair oxidative treatment may negatively affect EtG test results (false negative), whereas the mean PTCA content increased showing statistically significant differences between untreated and in vitro oxidative treated samples. The present study suggests that the determination of PTCA in routine hair analysis procedure could be useful in order to discover previous cosmetic treatment including oxidation.
... The mature hair follicle due to androgen hormones substituted with vellus hair follicle [24]. Hair follicles in humans consist of the ORS, the IRS, the hair shaft, the bulge region, and the dermal papilla [25]. ...
Article
The dermal papilla comprises mesenchymal cells in hair follicles, which play the main role in regulating hair growth. Maintaining the potential hair inductivity of dermal papilla cells (DPCs) and dermal sheath cells during cell culture is the main factor in in vitro morphogenesis and regeneration of hair follicles. Using common methods for the cultivation of human dermal papilla reduces the maintenance requirements of the inductive capacity of the dermal papilla and the expression of specific dermal papilla biomarkers. Optimizing culture conditions is therefore crucial for DPCs. Moreover, exosomes appear to play a key role in regulating the hair follicle growth through a paracrine mechanism and provide a functional method for treating hair loss. The present review investigated the biology of DPCs, the molecular and cell signaling mechanisms contributing to hair follicle growth in humans, the properties of the dermal papilla, and the effective techniques in maintaining hair inductivity in DPC cultures in humans as well as hair follicle bioengineering.
... Higher concentrations of hydroxycocaines in body hair may be related to a number of differences between head and body hair. Slower growth rates of body hair may allow greater deposition of drug into the hair per unit of length, from both the blood and the sebaceous gland duct at the lower end of the follicle infundibulum [23][24][25]. Also, body hair collections are often not aligned root-todistal in the foil, making segmental analysis difficult or impossible. ...
Article
Hydroxycocaines in hair were investigated with many hundreds of head and body hair samples. All samples were washed by a published extensive aqueous method prior to confirmation by LC-MS/MS. Concentrations, percent of cocaine, and ratios of para- and meta-hydroxycocaines to ortho-hydroxycocaine are presented. Hydroxycocaines as percent of cocaine did not appear to be affected by cocaine concentrations, but were shown to increase with cocaethylene concentrations. Stability of hydroxycocaines over a year of ambient storage was demonstrated. Ortho-hydroxycocaine was shown to be formed by exposure of cocaine-positive hair to peroxide, while para- and meta-hydroxycocaines were not. Presence of para- or meta-hydroxycocaine at > 0.05% of cocaine is proposed as indicating ingestion of cocaine. This indicator prevents black hair from being more likely interpreted as positive for ingestion than lighter colored hair.
... Almost all mammals have fur or other hair-related structures that help them adapt to their habitats. Hair usually provides thermal regulation and camouflage (Dawson et al., 2014) also it has also been related to some communication and mating processes (Buffoli et al., 2014). Beyond their functional role for animals, hair constitutes a habitat for multiple microorganisms on which they coexist and associate in complex ways with their host (Chen et al., 2018). ...
Article
Sloths have a dense coat on which insects, algae, and fungi coexist in a symbiotic relationship. This complex ecosystem requires different levels of control, however, most of these mechanisms remain unknown. We investigated the bacterial communities inhabiting the hair of two‐ (Choloepus Hoffmani) and three‐toed (Bradypus variegatus) sloths and evaluated their potential for producing antibiotic molecules capable of exerting control over the hair microbiota. The analysis of 16S rRNA amplicon sequence variants (ASVs) revealed that the communities in both host species are dominated by Actinobacteriota and Firmicutes. The most abundant genera were Brevibacterium, Kocuria/Rothia, Staphylococcus, Rubrobacter, Nesterenkonia, and Janibacter. Furthermore, we isolated nine strains of Brevibacterium and Rothia capable of producing substances that inhibited the growth of common mammalian pathogens. The analysis of the biosynthetic gene clusters (BCGs) of these nine isolates suggests that the pathogen‐inhibitory activity could be mediated by the presence of siderophores, terpenes, beta‐lactones, Type III polyketide synthases (T3PKS), ribosomally synthesized, and post‐translationally modified peptides (RiPPs), non‐alpha poly‐amino acids (NAPAA) like e‐Polylysin, ectoine or nonribosomal peptides (NRPs). Our data suggest that Micrococcales that inhabit sloth hair could have a role in controlling microbial populations in that habitat, improving our understanding of this highly complex ecosystem. This article is protected by copyright. All rights reserved.
... The current study is aimed at evaluating the effects of a meditation intervention on hair cortisol concentrations as a chronic stress biomarker in an undergraduate student population of a medical faculty. Hair cortisol levels represent free cortisol percentage which diffuses from capillary blood to growing pilose follicles, incorporating into the hair, where it remains without degradation [29,32]. The measurement of cortisol in hair is considered an excellent biomarker of chronic stress; its levels correlate positively with salivary cortisol, corroborated by many studies in the research about stressors affecting the population [33]. ...
Article
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Context. Meditation incorporation helps to fight against disorders such as depression, stress, and anxiety. Specifically, few studies have studied Osho’s Active Meditation on young people, but observed evidence using passive meditation shows that it could improve stress well-management, emotional control, and other mental unhealthy conditions. Goal. The present study pointed to evaluate the results of an occupational therapy program centered on active meditation on hair cortisol concentration in a sample of undergraduate healthcare students. Methods. Undergraduate students from the University of Chile’s health careers were divided at random into control (n=7) and treated groups (n=15). The treated group participated in an active meditation program once a week for three months. This treatment included different techniques such as Chakra Sounds, Nataraj, Mandala, Kundalini, Devavani, Gourishankar, and Nadabrahma. Hair samples were taken before and after the treatment period to measure cortisol. Results. The control group increased cortisol level 168.9±76.8 pg/mg compared with initial levels. The treated group shows a decrease of initial cortisol values in 28.5±12.8 pg/mg after meditation protocol application. Conclusions. Blending active meditation in students’ daily routine through occupational therapy intervention might prevent undergraduate students’ stress in healthcare careers.
... However, omentin-1 can stimulate hair growth through two possible pathways either as a vasodilator inducer 16 or through activation of phosphatidylinositol 3-kinase (PI3K) downstream effect. 17,18 Both vascular vasodilation 19 and PI13K have roles in stimulation of hair growth. 20,21 Results of this present study showed elevation of serum testosterone level in hirsute females than control. ...
Article
Background Hirsutism is a common clinical condition encountered in day‐to‐day practice. The androgenic causes account for more than 80% of these patients and include polycystic ovary syndrome (PCOS), which affects about 70%‐80% of hirsute women. The second most common cause is idiopathic hirsutism. Omentin‐1 is an adipokine mainly produced by visceral adipose tissue. Aim The current study aimed at evaluating omentin‐1 levels in hirsute females with PCOS and in idiopathic hirsutism. Patients and Methods Eighty‐five females were included in this study. They were classified into three groups: thirty hirsute patients with PCOS, thirty females with idiopathic hirsutism, and twenty‐five healthy control females. The participants were subjected to history taking, physical and dermatological examination. A gynecological history and radiological examination of the ovary also were done. Serum testosterone and omentin‐1 were measured by ELISA. Results Serum testosterone was statistically elevated in PCOS than other groups. Serum omentin‐1 in females with idiopathic hirsutism was statistically significantly higher than control and PCOS. There was a significant inverse correlation between serum testosterone level and serum omentin‐1 level. Conclusion Omentin‐1 may be involved in the pathogenic process of hirsutism.
... Hair does not have vital functions, but it represents an element of body image, and it is a complex organized structure that aims to protect the scalp. In particular, it is composed of proteins and different morphological components: (i) cuticle, consisting of several layers of thin and flat cells that aim to overlap one another to protect the cortex from physical and chemical insults; (ii) cortex, consisting of thick, rod-like cells, which contain keratin protein; and (iii) the medulla, which is located at the fiber's center and consists of round cells, separated by air pockets [304,305]. Hair products can be categorized into two main categories on the basis of the duration of the treatment effect: (i) temporary products, such as shampoos, conditioners, sprays, and temporary dyes, and (ii) permanent products, such as permanent waves, relaxers, bleaches, and permanent dyes. In general, the repeated and systematic exposure to potentially harmful molecules contained in hair products can have negative outcomes [306][307][308][309][310]. ...
Article
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Calcium phosphates (CaPs) belong to a class of biomimetic materials widely employed for medical applications thanks to their excellent properties, such as biodegradability, biocompatibility and osteoinductivity. The recent trend in the cosmetics field of substituting potentially hazardous materials with natural, safe, and sustainable ingredients for the health of consumers and for the environment, as well as the progress in the materials science of academics and chemical industries, has opened new perspectives in the use of CaPs in this field. While several reviews have been focused on the applications of CaP-based materials in medicine, this is the first attempt to catalogue the properties and use of CaPs in cosmetics. In this review a brief introduction on the chemical and physical characteristics of the main CaP phases is given, followed by an up-to-date report of their use in cosmetics through a large literature survey of research papers and patents. The application of CaPs as agents in oral care, skin care, hair care, and odor control has been selected and extensively discussed, highlighting the correlation between the chemical, physical and toxicological properties of the materials with their final applications. Finally, perspectives on the main challenges that should be addressed by the scientific community and cosmetics companies to widen the application of CaPs in cosmetics are given.
... Some possible reasons for the inconsistent results of latanoprost on eyelashes and eyebrows compared to the scalp hair, is their different growth patterns. These differences consist of androgen sensitivity, hair cycle duration, number of follicles, average growth rate, and anagen or telogen duration (29)(30)(31)(32)(33). Chemotherapy induced alopecia is also a major problem, and poses a great burden in cancer patients, with approximate incidence of 65% which represents a challenge especially in women and children. ...
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ABSTRACT Background: Alopecia is a common condition among males and females in all age groups. There are many treatment options with their own benefits and side effects. In some cases, the current treatments lack sufficient efficacy. Therefore, there is a need to probe for alternative treatments. Recently, latanoprost has been suggested as an effective therapeutic option for managing scalp baldness. Objectives : To review latanoprost effects in different types of scalp alopecia. Data sources: Scopus and Pubmed data-base Eligibility criteria and Methods: In this review, we included the studies evaluating effects of latanoprost in different types of scalp alopecia including androgenic alopecia and alopecia areata in the English literature. Results: There were promising results for latanoprost application in animal models of androgenic alopecia. Effects of latanoprost on human scalp alopecia were satisfying in mostof the studies. In alopecia areata of the eyelash, some studies observed remarkable improvement, while others didn’t notice significant changes. One study suggested that latanoprost could be used as an effective adjuvant therapy with corticosteroids in alopecia areata of the scalp. Conclusion : It seems that latanoprost can be an efficient agent in the treatment of alopecia areata of scalp. Key words: Prostaglandin F, Latanoprost, Alopecia areata, Androgenic alopecia, Prostaglandin analog, Bimatoprost, Alopecia, Review
... The top and bottom diameter of hair cone were approximately 36 µm and 54 µm. The variation of diameter of the hair is generally between 16-80 µm [39], [40]. The hair protruded from the skin at an angle of 30 • [41]. ...
Article
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The purpose of this work is to evaluate local power and electric field distributions inside high-resolution 3D anatomical CAD models of cutaneous appendages at 60 GHz upcoming for 5G/6G. The microscale resolution models of cutaneous nerves, lymphatics, pilosebaceous unit, microvasculature, eccrine sweat glands, Meissner corpuscle and Pacinian corpuscle were designed based on morphometric data and microscopic images. The Maxwell’s and Hanai’s mixture equations were employed to retrieve the complex permittivity of cutaneous appendages based on their free water content. The cutaneous appendages were exposed to a uniform plane wave. The finite element method was used to compute the power loss density ( ${\bm {PLD}}$ ) and internal electric field ( ${\bm {E}}$ ). The results indicate that the maximal ${\bm {PLD}}$ in cutaneous appendages occurred for ${\bm {E}}$ polarized along their longest dimension. Higher peak ${\bm {PLD}}$ was observed in high water content cutaneous appendages such as acrosyringium (45%), epidermal axon (37.9%), Pacinian corpuscle (32.5%), blood capillary (30.6%), lymph capillary (20%) and arrector pili muscle (13.5%) compared to the surrounding skin. Higher ${\bm {E}}$ was detected in low water content hair with the peak ${\bm {E}}$ 45.1% greater than in surrounding skin. The interfaces of the cutaneous appendages also manifested a boost (23.8%-60.9%) in ${\bm {PLD}}$ compared to the surrounding skin. Detailed physical interpretation of observed phenomena is provided in the article. These results provide an insight into microscale power deposition in skin at frequencies upcoming for wireless communications.
... The hair also has an important psychosocial role in society. Hair follicle number and distribution over the body and features of each hair is established during fetal development; no extra follicles are produced after birth (2). Hair follicles and sebaceous glands are developed from neuroectodermal and mesodermal origin. ...
Article
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Continuous industrial productivity and modern societies have resulted in excess artificial light. The altered circadian rhythm causes many diseases. During intrauterine life, the mother's maternal melatonin rhythm has a major role in influencing organ development. The aim of this study was to investigate the effect of maternal exposure to constant light on the structure and ultrastructure of neonatal skin. Twenty pregnant New Zealand rabbits were divided into two groups (n=10 each): control group (12-h light/dark) and constant light group (24-h light). Plasma maternal melatonin and corticosterone during pregnancy were determined. At the end of the experiment, the dorsal skin of the neonates of both groups was collected and prepared for histological, morphometric, and transmission electron microscopic study. Histological and morphometric results of skin of neonates from the constant light group revealed statistically significantly reduced epidermal thickness, decreased number of hair follicle, increased surface area of collagen, and decreased proliferating cell nuclear antigen (PCNA) positive cells. Ultrastructural examination showed wide intercellular spaces and disrupted desmosomal junctions in the epidermis. Earlier stages of hair follicles were also observed with indented shrunken nuclei, vacuolization, and swollen mitochondria. Dermal fibroblasts with dilated cisternae of rough endoplasmic reticulum containing electron-dense material were detected. Maternal melatonin was significantly reduced in the constant light group while maternal corticosterone showed no significant difference between groups. Therefore, normal maternal circadian rhythm is a key factor for the integrity of neonatal skin structure.
... It can also be divided in the horizontal direction; that is, the HF consists of an inner root sheath (IRS), which includes Henle's layer, Huxley's layer, the cuticle layer, the companion layer, and the outer root sheath (ORS), which contains keratinocytes, melanocyte stem cells, etc. The prominent bulge between the APM attached to the ORS and the sebaceous gland duct is the reservoir of human HFSCs (hHFSCs) [1,29,30]. We provide a figure of the HF structure and the specific markers of HFSCs (Fig. 1). ...
Article
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Hair follicle stem cells (HFSCs) are among the most widely available resources and most frequently approved model systems used for studying adult stem cells. HFSCs are particularly useful because of their self-renewal and differentiation properties. Additionally, the cyclic growth of hair follicles is driven by HFSCs. There are high expectations for the use of HFSCs as favourable systems for studying the molecular mechanisms that contribute to HFSC identification and can be applied to hair loss therapy, such as the activation or regeneration of hair follicles, and to the generation of hair using a tissue-engineering strategy. A variety of molecules are involved in the networks that critically regulate the fate of HFSCs, such as factors in hair follicle growth and development (in the Wnt pathway, Sonic hedgehog pathway, Notch pathway, and BMP pathway), and that suppress apoptotic cues (the apoptosis pathway). Here, we review the life cycle, biomarkers and functions of HFSCs, concluding with a summary of the signalling pathways involved in HFSC fate for promoting better understanding of the pathophysiological changes in the HFSC niche. Importantly, we highlight the potential mechanisms underlying the therapeutic targets involved in pathways associated with the treatment of hair loss and other disorders of skin and hair, including alopecia, skin cancer, skin inflammation, and skin wound healing.
... Hair is a unique character in mammals, and has important biological functions, such as mate attraction, skin protection, and social communication [1,31]. Alopecia is a common phenomenon in mammal, including humans, and can seriously affect health. ...
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Background The giant panda ( Ailuropoda melanoleuca ) is a threatened species endemic to China. Alopecia, characterized by thinning and broken hair, mostly occurs in breeding males. Alopecia significantly affects the health and public image of the giant panda and the cause of alopecia is unclear. Results Here, we researched gene expression profiles of four alopecia giant pandas and seven healthy giant pandas. All pandas were approximately ten years old and their blood samples collected during the breeding season. A total of 458 up-regulated DEGs and 211 down-regulated DEGs were identified. KEGG pathway enrichment identified that upregulated genes were enriched in the Notch signaling pathway and downregulated genes were enriched in ribosome, oxidative phosphorylation, and thermogenesis pathways. We obtained 28 hair growth-related DEGs, and identified three hub genes NOTCH1 , SMAD3 , and TGFB1 in PPI analysis. Five hair growth-related signaling pathways were identified with abnormal expression, these were Notch, Wnt, TGF-β, Mapk, and PI3K-Akt. The overexpression of NOTCH1 delays inner root sheath differentiation and results in hair shaft abnormalities. The delayed hair regression was associated with a significant decrease in the expression levels of TGFB1. Conclusions Our data confirmed the abnormal expression of several hair-related genes and pathways and identified alopecia candidate genes in the giant panda. Results of this study provide theoretical basis for the establishment of prevention and treatment strategies for giant pandas with alopecia.
... The skin is one of the most densely innervated organs of the body. [22][23][24] Acute stress activates the sympathetic axis of the autonomous nervous system (SA), which reacts very quickly and leads to a transient release of adrenaline from the adrenals and a local release of noradrenaline from peripheral adrenergic nerve fibres. The SA triggers activation of the endocrine hypothalamus-pituitaryadrenal axis (HPA), resulting in a transient release of cortisol from the adrenals into the blood stream, while the release of corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol from skin cells form a local equivalent of the central HPA. 25 Skin homeostasis is maintained by the additional activation of the cholinergic axis of the autonomic nervous system (CA). ...
Article
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Exposome factors that lead to stressed skin can be defined as any disturbance to homeostasis from environmental (meteorological factors, solar radiation, pollution or tobacco smoke) and/or internal exposure (unhealthy diet, hormonal variations, lack of sleep, psychosocial stress). The clinical and biological impact of chronic exposome effects on skin functions has been extensively reviewed, whereas there is a paucity of information on the impact of short-term acute exposure. Acute stress, which would typically last minutes to hours (and generally no more than a week), provokes a transient but robust neuroendocrine-immune and tissue remodeling response in the skin and can alter the skin barrier. Firstly, we provide an overview of the biological effects of various acute stressors on six key skin functions, namely the skin physical barrier, pigmentation, defenses (antioxidant, immune cell-mediated, microbial, and microbiome maintenance), structure (extracellular matrix and appendages), neuroendocrine, and thermoregulation functions. Secondly, we describe the biological and clinical effects on adult skin from individual exposome factors that elicit an acute stress response and their consequences in skin health maintenance. Clinical manifestations of acutely stressed skin may include dry skin that might accentuate fine lines, oily skin, sensitive skin, pruritus, erythema, pale skin, sweating, edema, as well as flares of inflammatory skin conditions such as acne, rosacea, atopic dermatitis, pigmentation disorders, and skin superinfection such as viral reactivation. Acute stresses can also induce scalp sensitivity, telogen effluvium, and worsen alopecia.
... Because HFSCs can differentiate into a variety of skin cells, we believe that T2DM inhibits the skin renewal capacity by inhibiting the Lgr5 HFSCs activation. Hair follicles are distributed in most areas of the body, but there are differences in distribution and morphology [43]. In humans, most of the hair on the body surface is small and colorless, while the hair on the head is longer and denser. ...
Article
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Background: Hair follicles are important accessory organs of the skin, and it is important for skin renewal and performs variety of important functions. Diabetes can cause several dermatoses; however, its effect on hair follicles is unclear. The purpose of this study was to investigate the effect of type II diabetes (T2DM) on the hair follicles of mice. Methods: Seven-week-old male C57BL/6 littermate mice were divided into two groups. The treatment group was injected with streptozotocin (STZ) to induce T2DM, and the control group was parallelly injected with the same dose of buffer. Seven days after injection, the back is depilated to observe the hair follicle regeneration. Hair follicle regeneration was observed by naked eyes and HE staining. The proliferation of the skin cells was observed by PCNA and K14 staining. The altered genes were screened by RNA sequencing and verified by qRT-PCR. In addition, Lgr5 + GFP/mTmG transgenic mice were used to observe the effect of T2DM on Lgr5 hair follicle stem cells (HFSC). And the expression of WNT4 and WNT8A were measured by Western Blot. Results: T2DM inhibited hair follicle regeneration. Compared to control mice, T2DM mice had smaller hair follicles, reduced skin thickness, and less expression of PCNA and K14. RNA sequencing showed that the two groups had significant differences in cell cycle and proliferation-related pathways. Compared with the control mice, the mRNA expression of Lgr4, Lgr5, Wnt4, and Wnt8a was decreased in the T2DM group. Moreover, T2DM inhibited the activation of Lgr5 HFSC and the expression of WNT4 and WNT8A. Conclusions: T2DM inhibited hair follicle regeneration and skin cells proliferation by inhibiting WNT-dependent Lgr5 HFSC activation. This may be an important reason for the reduction of skin renewal ability and the formation of chronic wounds caused by diabetes. It is important for the treatment of chronic diabetic wounds and the development of tissue engineering.
... Relying on these effects, HHF is a kind of natural nanocomposite absorption substrate with good economic performance. Moreover, HHF, as a natural polymer, will not have a negative effect on water when it is used as an absorbent and oil/water separation material 24 . Herein HHF, a cheap solid waste, was rationally selected as a substrate to fabricate the advanced oil/water separation material by attaching hydrophobic coating onto the HHF surface. ...
Article
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Frequent oil spill accidents and industrial wastewater discharge has always been one of the most severe worldwide environmental problems. To cope with this problem, many fluorine-containing and high-cost materials with superwettability have been extensively applied for oil–water separation, which hinders its large-scale application. In this work, a novel human hair fiber (HHF)-polymerized octadecylsiloxane (PODS) fiber was fabricated with a facile one-pot dip-coating synthesis approach, inspired by the self-assembly performance and hydrophobicity of OTS modification. The benefits of prominent hydrophobic/lipophilic behavior lie in the low surface energy, and a rough PODS coating was rationally adhered on the surface of HHF. Driven solely by gravity and capillary force, the HHF-PODS showed excellent oil/water separation efficiency (> 99.0%) for a wide range of heavy and light oil/water mixtures. In addition, HHF-PODS demonstrated durability toward different harsh environments like alkaline, acid, and salty solutions.
... These stem cells provide the necessary number and type of specialized cells that take part in the hair cycle, with precise regulation by various factors, including those from the perineural niche. HFs are innervated at the bulb and bulge including somatic sensory afferents and autonomic sympathetic nerves [31]. Sensory nerves not only feel the movement of hair [32], but support the Gli1expressing upper bulge (Gli1 + ) HFSCs as a peri-neural niche, participate in hair follicle growth when another anagen phase is initiated [33]. ...
Article
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Most epithelium tissues continuously undergo self-renewal through proliferation and differentiation of epithelial stem cells (known as homeostasis), within a specialized stem cell niche. In highly innervated epithelium, peripheral nerves compose perineural niche and support stem cell homeostasis by releasing a variety of neurotransmitters, hormones, and growth factors and supplying trophic factors to the stem cells. Emerging evidence has shown that both sensory and motor nerves can regulate the fate of epithelial stem cells, thus influencing epithelium homeostasis. Understanding the mechanism of crosstalk between epithelial stem cells and neurons will reveal the important role of the perineural niche in physiological and pathological conditions. Herein, we review recent discoveries of the perineural niche in epithelium mainly in tissue homeostasis, with a limited touch in wound repair and pathogenesis.
Article
Objectives: We used laser ablation inductively coupled plasma mass spectrometry to quantify gadolinium in hair samples from autopsy cases with gadolinium-based contrast agent (GBCA) exposure. Hair gadolinium data were correlated with gadolinium concentrations in brain, skin, and bone tissues from the same case to investigate a potential noninvasive method for gadolinium quantification and monitoring. Materials and methods: Medical records from autopsy cases at our institution were screened for history of GBCA exposure. Cases with exposure to a single type of GBCA with the most recent injection occurring within 1 year were identified and included in the study. The concentration of gadolinium in hair samples was analyzed by laser ablation inductively coupled plasma mass spectrometry, and brain (globus pallidus, dentate nucleus, white matter), bone, and skin tissues were analyzed by bulk inductively coupled plasma mass spectrometry. The mean of the maximum value in the hair samples was used to generate a representative measurement of the hair gadolinium concentration for each case. A linear regression analysis between each tissue type and hair was conducted to assess for possible correlation. Results: Tissue and hair samples from 18 autopsies (16 cases with exposure to GBCA, 2 controls) were included in the study. Comparing the different tissues revealed good correlation between some tissue types. The best model fit occurred between white matter and hair (R = 0.83; P < 0.0001) followed by the comparison between dentate nucleus and hair (R = 0.72; P < 0.0001) and dentate nucleus and skin (R = 0.70; P < 0.0001). Conclusions: A significant correlation in this study between hair gadolinium concentrations and brain and skin gadolinium concentrations suggests that hair may serve as a safe and effective biomonitoring tissue for patients who receive GBCA injections.
Chapter
Hair is a common piece of trace evidence found at a crime scene, however, often it is not possible to obtain DNA (due to the lack of a follicular root). These hair samples could potentially provide other intelligence, based on the molecular history of an individual that it contains. Currently, this type of analysis is performed using traditional hyphenated techniques gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS). However, these techniques require a large amount of hair, not a few single strands such as those typically found at a crime scene and also involve extensive sample preparation. Recently new technologies such as matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) have been used to monitor the distribution of drugs of abuse in single hair strands. Using this technology it is possible to reveal the distribution of compounds in the hair more accurately and in single strands as opposed to milligram quantities required by traditional hyphenated methods. The use of MALDI-MSI could provide law enforcement agencies with lifestyle information on an individual and help to narrow down the pool of suspects.
Article
Hair lipid composition varies by ethnic hair type and by hair layer. Lipids in the cuticle, cortex, and medulla of the hair shaft provide a protective barrier to environmental and chemical damage, prevent hair breakage and desorption, and affect the elastic and tensile properties of hair. The aim of this systematic review is to provide an overview of the lipid composition and ethnic differences of human hair, effects of external damage on lipid content and properties, and changes in hair lipid composition associated with disease states. PubMed/MEDLINE was searched up to March 2021 according to PRISMA guidelines for articles discussing the lipid content of human hair and effects of physical, chemical, or environmental damage, and disease. Fifty‐nine articles investigating the lipid content of hair were included for review. Lipids affect fluid permeability, hydration, strength, and texture of ethnic hair fibers. Lipid loss is accelerated by hair‐damaging treatments such as bleach, dye, perm, straightening, and surfactant use, and sun and aging processes, leading to dehydrated, breakable, disordered, and dull hair. Diseases including acne, alopecia, and breast, gastric, prostate, lung, and rectal cancers display elevated hair lipid levels. Lipids are vital in protection against damage and maintenance of healthy hair. Further studies are needed to investigate the effects of lipids on the structural properties of ethnic hair, and changes in hair lipid composition with various dermatologic and systemic diseases.
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The argan tree (Argania spinosa (L.) Skeels) is one of the most important floristic resources in Morocco. This Moroccan endemic tree is known for its numerous therapeutic and medicinal uses. In addition to some medicinal and cosmetic uses, argan fruit pulp and press cake are traditionally used by the Berber population for heating and feeding livestock. Molecular docking is an in silico approach that predicts the interaction between a ligand and a protein. This approach is mainly used in chemistry and pharmacology of natural products as a prediction tool with the purpose of selecting plant extracts or fractions for in vitro tests. The aim of this research is to study the evaluation of potential tyrosinase, collagenase, and elastase inhibitory activities of argan fruit press-cake and pulp extracts. Extracts were evaluated for their total phenolic content (TPC), and the major polyphenols of both press-cake and pulp extracts were submitted to molecular docking in order to determine the mechanisms of action of these compounds. Obtained results revealed that fruit pulp had the strongest dermocosmetic activities, as well as the highest TPC, with values above 55 mg gallic-acid equivalent per gram of dry matter (mgeq AG/gDM). Moreover, those results were positively correlated with the docking findings, suggesting that the pulp lead compounds have higher affinity with tyrosinase, collagenase, and elastase action sites. The results here presented are very promising and open new perspectives for the exploitation of argan-tree by-products as cosmetic agents towards the development of new anti-aging products.
Chapter
Federführend für den Behandlungswunsch sind die Zeichen des Alterungsprozesses, die man für die eigene Person nicht mehr akzeptiert. Das Gesicht setzt sich aus multiplen ästhetischen Zonen zusammen. Jede dieser ästhetischen Zonen bedarf eines differenzierten Behandlungskonzeptes, um den Gesamteindruck des Gesichtes in seiner jugendlichen Aussage zu fördern. Ein strukturiertes Vorgehen analysiert zunächst das Erscheinungsbild, beschäftigt sich dann mit seiner morphologischen Ausprägung und baut darauf das konkrete minimalinvasive Vorgehen auf. Neben den kleineren ästhetischen Zonen, z. B. Mundregion oder Augenregion, werden in diesem Buch Behandlungsstrategien vorgestellt, die sich mit dem Verjüngungskonzept, von dem oberen, dem mittleren und dem unteren Gesichtsdrittel, beschäftigen. Ebenfalls wird die Ästhetik der Mundpartie und des Zahnsystems berücksichtigt, da hier eine besondere Nähe zur ästhetischen dentofazialen Funktion besteht. Die Gesichtsästhetik schließt auch den Alterungsprozeß und die minimalinvasiven Therapiekonzepte von Hals, Ohren, Nase und Kopfbehaarung mit ein, die einen wesentlichen Beitrag zur Gesichtsästhetik leisten.
Article
Our study aimed to investigate the efficacy of treatment combined electrocauterization after removal of apocrine sweat glands with ultrasound-guided botulinum toxin type A (BOTOX) injection for adolescents with axillary bromhidrosis. From January 2015 to January 2018, 90 adolescents with axillary bromhidrosis were recruited and randomly divided into three groups (group A, B, and C). Patients in group A underwent electrocauterization after removal of apocrine sweat glands, patients in group B received ultrasound-guided BOTOX injection, and patients in group C had electrocauterization after removal of apocrine sweat glands followed by ultrasound-guided BOTOX administration after two weeks. All patients were followed up for one year. Percentages of axillary malodor score at twelve months after treatments comparing with pre-operation for group A, group B, and group C were 20.2%, 27.5%, and 12.5%, respectively. Significant statistical differences were observed in changes of axillary malodor score among the three groups at three, six, nine and twelve months postoperatively. Satisfaction rates of group A, group B, and group C were 90.0%, 93.3%, and 96.7%, respectively. The side effects after surgery in group A were similar with group C, and no side effect was observed in group B. One-year postoperative scar formation rate of group A was 16.7%, which was significantly higher than that of group B (0) and group C (6.66%). Combination of electrocauterization after removal of apocrine sweat glands with ultrasound-guided BOTOX injection showed better treatment effects.
Article
The application of photobiomodulation (PBM) in regenerative medicine has expanded to the treatment of alopecia caused by various reasons. However, the mechanisms responsible for its effects are poorly understood. Here, we aimed to investigate the effects of PBM on hair regeneration in injured skin and to explore the underlying mechanisms. The scratched epidermis or dermis models were established in C57 mice aged 7–8 weeks. We found that the scratched epidermis had no influence on hair regeneration, but the scratched dermis led to obvious hair follicle atrophy and significantly influenced hair regeneration. The wounds in scratched dermis models were treated with PBM (655 nm, 3 J/cm² [10 min]) and the hair regeneration and cell proliferation in hair follicle were evaluated. Compared with control, the hair coverage level was significantly enhanced after PBM treatment. Sox9⁺ and PCNA⁺ cells in hair follicle were obviously observed in PBM-treated group, but not in control. In vitro, the effects of PBM on the function of dermal papilla cells (DPCs) were investigated. The results showed that the migration of DPCs was increased significantly by PBM (655 nm, 3 J/cm² [10 min]), whereas no effect was found on proliferation. Furthermore, we found that PBM promoted exosome secretion of DPCs, accompanied by the activation of Akt/GSK-3β/β-catenin pathway. AKT inhibitor MK-2206 effectively blocked PBM-induced migration and exosome secretion of DPCs. These findings suggest that the enhanced migration and exosome secretion of DPCs mediated by the Akt/GSK-3β/β-catenin pathway were responsible for the promotion of hair regeneration in injured skin by PBM.
Article
Abstracrt Over the years, several studies have shown that many factors are likely to affect the results of forensic hair analyses and complicate their interpretation. Among these factors, one of the major drawbacks in hair analysis is the affectability of deposited xenobiotics by cosmetic treatments, which could be eventually used to adulterate the sample. It is well known that some cosmetic treatments containing hydrogen peroxide, such as permanent dyeing or bleaching, lead to the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a melanin degradation product. Considering that PTCA is also an endogenous compound, spontaneously formed by natural oxidation of melanin, its only detection in hair is not enough to confirm a cosmetic oxidative treatment. For this reason, the aim of the present work was to develop and validate a reliable liquid–liquid extraction method in ultra-high-performance liquid chromatographic–tandem mass spectrometry for the determination of endogenous PTCA in hair from a wide multi-ethnic population (African, Arab, Asian-Pacific, Caucasian, Hispanic and Indian). According to previous studies, untreated hair samples showed a PTCA content of 8.54 ± 5.72 ng/mg (mean ± standard deviation [SD]), ranging between 0.44 and 23.7 ng/mg; after in vitro cosmetic bleaching, PTCA increased to 16.8 ± 6.95 ng/mg (range: 4.16–32.3 ng/mg). Comparing baseline PTCA levels of each subgroup with the others, we could not observe any statistically significant difference, except for Caucasians (P < 0.05), wherein the concentrations were lower. Further studies and a wider sampling are necessary to elucidate the role of PTCA as diagnostic marker of cosmetic hair treatment in forensic field.
Article
Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.
Article
Purpose: To discuss the advantages and limitations of hair follicle-derived cell transplantation (FCT) in vitiligo, compared to the epidermal cell transplantation (ECT), and the knowledge gap which is required to be bridged. Methods: The papers relevant to the purpose was reviewed. Results: Surgical approaches for treating vitiligo are based on the idea of replenishing lost melanocytes. Skin and hair follicles as the main sources of melanocytes have been applied for this purpose transferring the whole tissue or tissue-derived cell suspension to the vitiligo lesions. Considering the differences between hair follicle and epidermis in terms of the constituting cell populations, phenotype and function of melanocytes, and micro-environmental factors, different response of vitiligo patients to treatment with FCT or ECT would be expected theoretically. However, there is currently a lack of evidence on such a difference. However, ECT appears to be a more feasible, less time-consuming, and more comfortable treatment for both physicians and patients. Conclusion: Although the current evidence has not shown a significant difference between ECT and FCT in terms of efficacy, ECT appears to be more feasible specifically in the treatment of large lesions. However, further randomized controlled clinical trials with larger sample sizes and longer follow-up durations are required to be conducted to draw a definite conclusion on comparing FCT with ECT in terms of the safety, efficacy, durability of the therapeutic effects, and indications in vitiligo patients. Full-text available: https://rdcu.be/b8ki2
Article
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Eccrine sweat gland (ESG) and hair follicle (HF) are different skin appendages but share many common development characteristics. Although the morphology of adult ESG and HF is obviously different, it is difficult to distinguish ESG placodes from HFs placodes morphologically. To study the fate determination of ESG and HF, specific antigen markers for ESG placodes and HF placodes must be found first to distinguish them. In the study, we detected the expression of commonly used keratins 4, 5, 7–10, 12, 14, 15, 17–20, 27 and 73, and the reported ESG and HF specific markers, P-cadherin, Lymphoid enhancer factor 1 (LEF1), LIM Homeobox gene 2 (LHX2), Na+/K+-ATPase (NKA) and Na+-K+-2Cl− cotransporter 1 (NKCC1) in ESG and HF placodes by single-immunofluorescence staining and double-immunofluorescence staining. To further verify the results of immunofluorescence staining, Western blot (WB) was used to detect the differential antigen and some co-expressed antigens of ESG and HF placodes. The results showed that both ESG and HF placodes expressed K4/5/14/1517/18, P-cadherin and LEF1, neither expressed K7/8/9/10/12/19/20/27/73, NKA or NKCC1. HF placodes specifically expressed LHX2. Combination of LHX2 and co-expressed antigen K14, can distinguish ESG placodes from HF placodes. We conclude that LHX2 is a specific marker for HF placodes, and ESG placodes and HF placodes can be distinguished by double immunofluorescence staining of the specific marker LHX2 and the co-expressed markers, such as K4, K5, K14, K15, K17, K18, P-cadherin and LEF1.
Article
With the positive outcomes of various cell therapies currently under pre-clinical and clinical studies, there is a significant interest in novel stem cell sources with unique therapeutic properties. Studies over the past two decades or so demonstrated the feasibility to isolate multipotent/pluripotent stem cells from hair follicles. The easy accessibility, high proliferation and differentiation ability as well as lack of ethical concerns associated with this stem cell source make hair follicle stem cells (HFSCs) attractive candidate for cell therapy and tissue engineering. This review discusses the various stem cell types identified in rodent and human hair follicles and ongoing studies on the potential use of HFSCs for skin, bone, cardio-vascular, and nerve tissue engineering.
Article
Beautiful and healthy hair is a sign of health and beauty. Knowledge of hair and hair care is important to achieve that. This article reviews the anatomy, diseases and the diagnosis of common hair diseases. It also suggests the general management, nutritional requirements and hair care methods. Hidden harms of the hair products are also discussed. Understanding one's hair problems and managing them rationally can help to maintain the hair and also to revive them.
Article
This study utilized laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify gadolinium in the hair of autopsy cases that had received gadolinium-based contrast agents (GBCAs) before death. Consecutive autopsy cases were reviewed for GBCA injections and subjects who received a single type of GBCA in the year before death were included. Hair samples were analyzed using LA-ICP-MS as a line scan technique and parameters were optimized to maximize instrument sensitivity, accuracy, and precision. Linear regression analyses between hair measures and gadolinium dose were executed. LA-ICP-MS analysis produced a time-resolved record of GCBA exposure, with the position of the gadolinium peak maxima along the hair shaft providing a good estimate for the day that GBCA injection occurred (R2 = 0.46; p = 0.0022); however, substantial within and between subject variation in the position of the GBCA peak was observed. Average area under the curve for gadolinium peaks in the hair samples was a better predictor of gadolinium dose (R2 = 0.41; p = 0.0046), compared to the average of peak maxima concentration. Correlation between area under the curve and dose suggests that LA-ICP-MS analysis of hair may be an effective method to evaluate gadolinium levels in subjects in vivo after exposure to GBCAs. This study demonstrates that analysis of human hair using techniques with high spatial resolution such as LA-ICP-MS has excellent potential to reveal time-dependent signatures of past exposures.
Chapter
Hair, a shared feature of all mammals, plays an important role in environmental protection, sensory enhancement, temperature regulation, and debris removal. Human hair has been historically classified into three ethnic subgroups: Asian, African, and Caucasian. While these groupings are grossly unscientific and fail to recognize the complex phenotypic diversity of hair, they continue to persist in scientific literature due to ease of reader comprehension and challenges classifying hair. This chapter explores the anatomy of hair, hair follicle immune privilege, the hair cycle, hair pigmentation, the science of hair curl, and alternative ways to classify hair beyond ethnicity.
Article
A methanol extract from Isodonis Herba demonstrated significant proliferative effect on human hair follicle dermal papilla cells (HFDPC, % of control: 150.0 ± 2.0% at 20 µg/mL, p < 0.01). From the extract, 14 ent-kaurane-type diterpenoids (1–14), two abietane-type diterpenoids (15 and 16) and four triterpenoids (17–20) were isolated. Among the isolates, enmein (1, 160.9 ± 3.0% at 20 µM, p < 0.01), isodocarpin (2, 169.3 ± 4.9% at 5 µM, p < 0.01), nodosin (4, 160.5 ± 12.4% at 20 µM, p < 0.01), and oridonin (8, 165.4 ± 10.6% at 10 µM, p < 0.01) showed the proliferative effects. The principal component enmein (1) activated the expression of vascular endothelial growth factor (VEGF) mRNA, upregulated the production of VEGF and increased levels of phospho-Akt, phospho-GSK-3β, and β-catenin accumulation in HFDPC, which could be the mechanism of these activate proliferation activity.
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It has long been known that the testis is an immunologically privileged site in the body, and that human seminal plasma possesses a generalized immunosuppressive activity. Multiple factors participate in the establishment of immunotolerance in the testis: the blood–tubular barrier; the local production of immunosuppressive molecules by Sertoli cells; and the Fas system as regulator of immunological homeostasis in both physiological and pathological conditions. Cytokine-induced up-regulation of Fas as well as of integrin ligands, which are known to be specific binding molecules for lymphocytes on the Sertoli cell surface, indicates that the ‘nursing’ cells of seminiferous epithelium might be important in the impairment of immune privilege, causing autoimmune orchitis. In addition, the soluble form of Fas-ligand protein present in the seminal plasma of infertile patients might suggest a role for this immunomodulatory protein in male infertility. Finally, an understanding of the mechanisms underlying immune privilege in the testis and in semen might help to clarify how cells expressing ‘non-self’ antigens (such as male gametes) can escape the immune system in both the male and female genital tracts.
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ABSTRACT: Correction to Wu DD, Irwin DM, Zhang YP: Molecular evolution of the keratin associated protein gene family in mammals, role in the evolution of mammalian hair. BMC Evol Biol 2008, 8:241.
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Five hundred adults aged between 18-35 years were used for the study. The aim of this study was to provide a reference document for Nigerians on the distribution of phalangeal hair using a sample population of Yorubas resident in Ilorin and to assess the effect of job type, age and sex hair distribution. With the help of a hand lens, the pattern and frequency of hair distribution on the proximal, intermediate and distal were randomly chosen from the population. Proximal phalangeal hair was absent in 10 (2%) individuals who were all males. The highest frequency distribution (51%) was found on the 2-3-4-5, digits of proximal phalanges (26% in males and 25% females) while the least (1%) was the 3-5; 1-2-3-5 digital pattern. It was observed that the frequency of middle phalangeal hair was low (1%). Females had less phalangeal hair. Hair was absent on the distal phalanges. Distribution is similar to other populations reported. Age was not a factor in the distribution but individual's job type and sex had effect on hair distribution. Hence people engaged in wet work should wear gloves.
Article
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Hair is unique to mammals. Keratin associated proteins (KRTAPs), which contain two major groups: high/ultrahigh cysteine and high glycine-tyrosine, are one of the major components of hair and play essential roles in the formation of rigid and resistant hair shafts. The KRTAP family was identified as being unique to mammals, and near-complete KRTAP gene repertoires for eight mammalian genomes were characterized in this study. An expanded KRTAP gene repertoire was found in rodents. Surprisingly, humans have a similar number of genes as other primates despite the relative hairlessness of humans. We identified several new subfamilies not previously reported in the high/ultrahigh cysteine KRTAP genes. Genes in many subfamilies of the high/ultrahigh cysteine KRTAP genes have evolved by concerted evolution with frequent gene conversion events, yielding a higher GC base content for these gene sequences. In contrast, the high glycine-tyrosine KRTAP genes have evolved more dynamically, with fewer gene conversion events and thus have a lower GC base content, possibly due to positive selection. Most of the subfamilies emerged early in the evolution of mammals, thus we propose that the mammalian ancestor should have a diverse KRTAP gene repertoire. We propose that hair content characteristics have evolved and diverged rapidly among mammals because of rapid divergent evolution of KRTAPs between species. In contrast, subfamilies of KRTAP genes have been homogenized within each species due to concerted evolution.
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Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chase as our model and tried to put the adult hair follicle growth cycle in perspective. We have tried to sketch the adult hair follicle cycle, as we know it today and what needs to be known. Above all, we hope that this work will serve as an introduction to basic biologists who are looking for a defined biological system that illustrates many of the challenges of modern biology: cell differentiation, epithelial-mesenchymal interactions, stem cell biology, pattern formation, apoptosis, cell and organ growth cycles, and pigmentation. The most important theme in studying the cycling hair follicle is that the follicle is a regenerating system. By traversing the phases of the cycle (growth, regression, resting, shedding, then growth again), the follicle demonstrates the unusual ability to completely regenerate itself. The basis for this regeneration rests in the unique follicular epithelial and mesenchymal components and their interactions. Recently, some of the molecular signals making up these interactions have been defined. They involve gene families also found in other regenerating systems such as fibroblast growth factor, transforming growth factor-beta, Wnt pathway, Sonic hedgehog, neurotrophins, and homeobox. For the immediate future, our challenge is to define the molecular basis for hair follicle growth control, to regenerate a mature hair follicle in vitro from defined populations, and to offer real solutions to our patients' problems.
Article
Full-text available
It has long been known that the testis is an immunologically privileged site in the body, and that human seminal plasma possesses a generalized immunosuppressive activity. Multiple factors participate in the establishment of immunotolerance in the testis: the blood-tubular barrier; the local production of immunosuppressive molecules by Sertoli cells; and the Fas system as regulator of immunological homeostasis in both physiological and pathological conditions. Cytokine-induced up-regulation of Fas as well as of integrin ligands, which are known to be specific binding molecules for lymphocytes on the Sertoli cell surface, indicates that the 'nursing' cells of seminiferous epithelium might be important in the impairment of immune privilege, causing autoimmune orchitis. In addition, the soluble form of Fas-ligand protein present in the seminal plasma of infertile patients might suggest a role for this immunomodulatory protein in male infertility. Finally, an understanding of the mechanisms underlying immune privilege in the testis and in semen might help to clarify how cells expressing 'non-self' antigens (such as male gametes) can escape the immune system in both the male and female genital tracts.
Article
Full-text available
Recent genetic and molecular studies of hair follicle (HF) biology have provided substantial insight; however, the molecular data, including expression patterns, cannot be properly appreciated without an understanding of the basic cellular rearrangements and interactions that underpin HF cyclic transformations. We present a novel interpretation of the major cellular processes that take place during HF cycling--the hypothesis of hair follicle predetermination. This hypothesis is an extension of previous models of HF cellular kinetics but has two critical modifications: the dual origin of the cycling portion of the HF, and the timing of the recruitment of stem cells. A compilation of evidence suggests that the ascending portion of the HF (hair shaft and inner root sheath) arises not from bulge-located HF stem cells that contribute to the formation of only the outer root sheath (ORS), but instead from the germinative cells localized in the secondary hair germ. In middle anagen, upon completion of the downward growth of the HF, cells derived from the bulge region migrate downward along the ORS to reside at the periphery of the HF bulb as a distinct, inactive cell population that has specific patterns of gene expression - 'the lateral disc'. These cells survive catagen-associated apoptosis and, under the direct influence of the follicular papilla (FP), transform into the hair germ and acquire the ability to respond to FP signaling and produce a new hair. Thus, we propose that the specific sensitivity of germ cells to FP signaling and their commitment to produce the ascending HF layers are predetermined by the previous hair cycle during the process of transformation of bulge-derived lateral disc cells into the secondary hair germ.
Article
The structure, chemistry, and physical properties of the human hair cuticle are reviewed, and the role of the covalently linked fatty acids, notably 18-methyl eicosanoic acid (18-MEA), contained therein, is discussed. Differential friction in hair is considered, and it is argued that this property normally facilitates the parallel alignment of hairs on the scalp and aids the rejection of macroscopic scalp surface detritus, to the owner's benefit. The hair seems to possess a natural process of surface repair that, by the gradual mechanical attrition of cuticle, aids in the retention of the hair's differential frictional behavior and in the retention of the associated benefits.
Chapter
This chapter reviews the functions of hair, its structure and the processes occurring during the hair growth cycle, the changes which can occur with the seasons, and the importance of the main regulator of human hair growth, the androgens. Its main focus lies on human hair growth. Mammalian skin produces hair everywhere except for the glabrous skin of the lips, palms, and soles. Although obvious in most mammals, human hair growth is so reduced with tiny, virtually colorless vellus hairs in many areas, that we are termed the “naked ape.” Externally hairs are thin, flexible tubes of dead, fully keratinised epithelial cells; they vary in color, length, diameter, and cross-sectional shape. Inside the skin hairs are part of individual living hair follicles, cylindrical epithelial downgrowths into the dermis, and subcutaneous fat, which enlarge at the base into the hair bulb surrounding the mesenchyme-derived dermal papilla. Human hair's main functions are protection and communication; it has virtually lost insulation and camouflage roles, although seasonal variation and hair erection when cold indicate the evolutionary history. Children's hairs are mainly protective; eyebrows and eyelashes stop things entering the eyes, while scalp hair probably prevents sunlight, cold, and physical damage to the head and neck.
Article
Background and Design: The few articles published on the interactions between psychological factors and alopecia seem to yield contrasting results. To assess the relationships between alopecia, gender, Diagnostic Statistical Manual of Mental Disorders, Revised Third Edition personality disorders, and psychopathologic symptoms reactive to alopecia, we administered the Personality Disorders Questionnaire-Revised and the Symptoms Checklist-90 to a randomly selected sample of 116 outpatients with androgenetic alopecia. Results: The prevalence of personality disorders in subjects with androgenetic alopecia proved to be significantly higher than the prevalence of such diagnoses in the general population. Women did not show a higher prevalence of personality disorders or more psychopathologic symptoms than men. The factor analysis demonstrated the existence of three personality profiles (F1, F2, and F3) significantly and specifically associated with the subject's gender and with the psychopathologic reactive symptoms, measured using the Symptoms Checklist-90. Conclusions: The most important factor in developing a psychopathologic reaction to alopecia seems to be the presence of a Diagnostic Statistical Manual of Mental Disorders, Revised Third Edition personality disorder and not the subject's gender.(Arch Dermatol. 1994;130:868-872)
Article
All living organisms are constantly challenged by a diversity of exogenous (environmental, psychological, social) and endogenous stimuli or stressors, which induce general or local biological responses to protect or adapt the organism to the stressor(s). 1 The systemic biological response of the organism to exogenous stressors (or classical stress response) includes activation of the hypothalamic-pituitary-adrenal axis and release of hypothalamic corticotropin-releasing hormone (CRH) that activates pituitary CRH receptors (CRH-R) followed by the production and release of proopiomelanocortin-derived peptides and adrenal hormones. 2,3 Systemic stress response also includes the modulation of the autonomic nervous and immune systems: neuroendocrine hormones and neurotransmitters influence the function of the immune system that reciprocally regulate CNS functions through cytokine release. 4
Article
Human and murine skin are prominent extrapituitary sources and targets for POMC products. The expression of, for example, ACTH, α-MSH, β-endorphin, and MC-1-receptors fluctuates during synchronized hair follicle cycling in C57BL/6 mice. Since hair growth can be induced by ACTH injections in mice and mink, and since high doses of MSH peptides modulate epidermal and/or follicle keratinocyte proliferation in murine skin organ culture, some POMC products may operate as locally generated growth modulators, in addition to their roles in cutaneous pigment and immunobiology. Intrafollicularly generated ACTH and α-MSH as well as their cognate receptors may assist in the maintenance of the peculiar immune privilege of the anagen hair bulb. Possibly, they are also involved in the development of the follicle pigmentary unit, with whose generation their expression coincides. Given that murine skin also expresses (in a hair-cycle-dependent way) CRH and CRH-R, which control pituitary POMC expression and in view of the fact that CRH arrests follicles in telogen, this suggests the existence of a local skin POMC system (SPS). This may be an integral component of cutaneous stress response-systems, and may most instructively be studied using the murine hair cycle as a model.
Article
Penetration of topically applied compounds may occur via the stratum corneum, skin appendages and hair follicles. The follicular infundibulum increases the surface area, disrupts the epidermal barrier towards the lower parts of the follicle, and serves as a reservoir. Topical delivery of active compounds to specific targets within the skin, especially to distinct hair follicle compartments or cell populations, may help to treat local inflammatory reactions selectively, with reduced systemic side-effects. Various in vitro and in vivo methods exist for studying the hair follicle structure and follicular penetration pathways. These include cyanoacrylate skin surface stripping, confocal microscopy and cyanoacrylate scalp follicle biopsy. The complex anatomical structure as well as the cyclical activity of the hair follicle must be taken into consideration when designing delivery systems. In addition, delivery into and retention inside the infundibular reservoir are controlled by, for example, molecule or particle size, their polarity and the type of preparation. Preferred penetration depth and storage time must also be considered. Particles with release mechanisms should be preferred; however, the release of drugs from nanoparticles still requires further investigations.
Article
Hair examinations and comparisons conducted by forensic scientists often provide investigative and associative information. Apart from its length and its natural color, hair displays a morphologic diversity both macroscopically and microscopically. Pseudogenization of <phihHaA type I hair keratin gene inactivation highlights dramatic differences and is thought to be one of the strongest reasons for localization of hair in human. Therefore, humans have several different types of hair that can be classified depending on their body position and form. Size, angle of penetrance through the skin, embryological time of first appearance, and structural variations in the hair follicles are all taken into account when classifying hair types. However, the classification of differential types of hair quantitative traits in human is yet to be undertaken. An attempt has been made in the present study to understand the variation by using the histomorphological and quantitative variables of 540 hair strands (180 each scalp, axillary and pubic hair) of 18 adult Bengalee Hindu caste females. Apart from variation in histomorphological variables, quantitative variables regarding shaft and medulla diameter demonstrated variation in terms of being significantly higher (p < 0.05) in pubic hair compared to that of axillary and scalp hair. Therefore, the present study envisaged that variability in histomorphological and quantitative traits in different areas of human could be one of the important criteria for personal identification in forensic research.
Article
Cosmetic surgical procedures, including hair transplantation and face-lift surgery, are becoming increasingly popular. However, there is very little information regarding the associated development of dermatological conditions following these procedures. Lichen planopilaris (LPP) is an uncommon inflammatory hair disorder of unknown aetiology that results in permanent alopecia and replacement of hair follicles with scar-like fibrous tissue. Frontal fibrosing alopecia (FFA), a variant of LPP, involves the frontal hairline and shares similar histological findings with those of LPP. We report 10 patients who developed LPP/FFA following cosmetic scalp surgery. Seven patients developed LPP following hair transplantation, and three patients developed FFA following face-lift surgery. In all cases there was no previous history of LPP or FFA. There is currently a lack of evidence to link the procedures of hair transplantation and cosmetic face-lift surgery to LPP and FFA, respectively. This is the first case series to describe this connection and to postulate the possible pathological processes underlying the clinical observation. Explanations include Koebner phenomenon induced by surgical trauma, an autoimmune process targeting an (as yet, unknown) hair follicle antigen liberated during surgery or perhaps a postsurgery proinflammatory milieu inducing hair follicle immune privilege collapse and follicular damage in susceptible individuals.
Article
Loose anagen syndrome (LAS) is a benign, self-limiting condition where anagen hairs are easily and painlessly extracted. It is mainly reported in childhood; however, it may variably present in adulthood as well. The presence of anagen hair devoid of its sheath and with 'floppy sock appearance' is a characteristic feature of loose anagen hair (LAH) on trichogram. LAH can be seen in normal population and in alopecia areata. The percentage of LAH in LAS is more than 50%. The histopathological findings show clefting between the layers of hair and are very useful in differentiating LAS from alopecia areata. Here, a review on the diagnostic criteria and practical guidelines are discussed so as to enable the trichologist in managing this benign, self-limiting condition and differentiating it from the other causes of non-scarring alopecias.
Article
The human keratin family comprises 54 members, 28 type I and 26 type II. Out of the 28 type I keratins, 17 are epithelial and 11 are hair keratins. Similarly, the 26 type II members comprise 20 epithelial and 6 hair keratins. As, however, 9 out of the 37 epithelial keratins are specifically expressed in the hair follicle, the total number of hair follicle-specific keratins (26) almost equals that of those expressed in the various forms of epithelia (28). Up to now, more than half of the latter have been found to be involved in inherited diseases, with mutated type I and type II members being roughly equally causal. In contrast, out of the 26 hair follicle-specific keratins only 5 have, at present, been associated with inherited hair disorders, while one keratin merely acts as a risk factor. In addition, all hair follicle-specific keratins involved in pathologies are type II keratins. Here we provide a detailed description of the respective hair diseases which are either due to mutations in hair keratins (monilethrix, ectodermal dysplasia of hair and nail type) or hair follicle-specific epithelial keratins (two mouse models, RCO3 and Ca(Rin) as well as pseudofolliculitis barbae).
Article
Immune privilege (IP) is important in maintaining ocular health. Understanding the mechanism underlying this dynamic state would assist in treating inflammatory eye diseases. Despite substantial progress in defining eye IP mechanisms, because of the scarcity of human ocular tissue for research purposes, most of what we know about ocular IP is based on rodent models (of unclear relevance to human eye immunology) and on cultured human eye-derived cells that cannot faithfully mirror the complex cell-tissue interactions that underlie normal human ocular IP in situ. Therefore, accessible, instructive, and clinically relevant human in vitro models are needed for exploring the general principles of why and how IP collapses under clinically relevant experimental conditions and how it can be protected or even restored therapeutically. Among the few human IP sites, the easily accessible and abundantly available hair follicle (HF) may offer one such surrogate model. There are excellent human HF organ culture systems for the study of HF IP in situ that instructively complement in vivo autoimmunity research in the human system. In this article, we delineate that the human eye and HF, despite their obvious differences, share key molecular and cellular mechanisms for maintaining IP. We argue that, therefore, human scalp HFs can provide an unconventional, but highly instructive, accessible, easily manipulated, and clinically relevant preclinical model for selected aspects of ocular IP. This essay is an attempt to encourage professional eye researchers to turn their attention, with appropriate caveats, to this candidate surrogate model for ocular IP in the human system.
Article
Most mammals are coated with pigmented hair. Melanocytes in each hair follicle produce melanin pigments for the hair during each hair cycle. The key to understanding the mechanism of cyclic melanin production is the melanocyte stem cell (MelSC) population, previously known as 'amelanotic melanocytes'. The MelSCs directly adhere to hair follicle stem cells, the niche cells for MelSCs and reside in the hair follicle bulge-subbulge area, the lower permanent portion of the hair follicle, to serve as a melanocyte reservoir for skin and hair pigmentation. MelSCs form a stem cell system within individual hair follicles and provide a 'hair pigmentary unit' for each cycle of hair pigmentation. This review focuses on the identification of MelSCs and their characteristics and explains the importance of the MelSC population in the mechanisms of hair pigmentation, hair greying, and skin repigmentation.
Article
Middle phalangeal hair has been a focus of study in different populations for the absence or presence of this trait. Clinically, this is often perceived as a solely cosmetic feature. However, because of a series of patients questioning the presence of hair on this location, we have performed a more in-depth literature-based evaluation of the trait. The goal of this manuscript was to examine the clinical significance of this anthropological phenomenon. A literature review was performed that focused on the differences of this trait in terms of pattern of presentation, age, race, sex, and usage as an identifiable marker for medical significance in certain medications and criteria for tailored treatment. Anatomically, middle phalangeal hair is mostly on the fourth finger and more ulnar rather than central or symmetric in pattern of deviation. Its presence has been most associated with high prenatal androgen exposure, predisposing patients to suffer from adverse side effects from oral contraceptives. Phalangeal hair may be helpful in tailoring treatment to certain patients from different ethnic backgrounds, and particularly in individuals with unknown ancestry.
Article
The role of neurohormones and neuropeptides in human hair follicle (HF) pigmentation extends far beyond the control of melanin synthesis by α-MSH and ACTH and includes melanoblast differentiation, reactive oxygen species scavenging, maintenance of HF immune privilege, and remodeling of the HF pigmentary unit (HFPU). It is now clear that human HFs are not only a target of multiple neuromediators, but also are a major non-classical production site for neurohormones such as CRH, proopiomelanocortin, ACTH, α-MSH, ß-endorphin, TRH, and melatonin. Moreover, human HFs have established a functional peripheral equivalent of the hypothalamic-pituitary-adrenal axis. By charting the author's own meanderings through the jungle of hair pigmentation research, the current perspectives essay utilizes four clinical observations - hair repigmentation, canities, poliosis, and 'overnight greying'- as points of entry into the enigmas and challenges of .pigmentary HF neuroendocrinology. After synthesizing key principles and defining major open questions in the field, selected research avenues are delineated that appear clinically most promising. In this context, novel neuroendocrinological strategies to retard or reverse greying and to reduce damage to the HFPU are discussed.
Article
A thorough characterization of the morphological structure and physical properties is essential for an understanding of human hair. A number of techniques such as scanning electron microscopy, transmission electron microscopy and confocal microscopy have been used to study hair surfaces. Recently, atomic force microscopy (AFM) has emerged as an ideal method for the non-invasive examination of hair surfaces. To investigate the effects of aging on normal Korean hair diameter and surface features using AFM. We enrolled 60 Korean volunteers of various ages who had no hair diseases. We analyzed hair diameter, AFM images of the hair surface, cuticular descriptors and micro-scale mechanical properties for their associations with aging. Results: Hair diameter was found to increase for the first 20-30 years of life, after which it began to decrease. AFM images of most of the younger subjects showed typical step-like topographic properties with clear scale edges. The AFM images of most of the older subjects revealed dilapidated structures, poorly demarcated scale edges and undulated surfaces. Among the cuticular descriptors, surface roughness increased significantly with age. Force to distance analysis demonstrated a dependence on age. These results suggest that aging causes changes in hair diameter and surface structure.
Article
Cicatricial (scarring) alopecia results from irreversible damage to epithelial stem cells located in the bulge region of the hair follicle, generally as a result of inflammatory mechanisms (eg, in the context of autoimmune disease). In primary cicactricial alopecia (PCA), the hair follicle itself is the key target of autoaggressive immunity. This group of permanent hair loss disorders can be classified into distinct subgroups, characterized by the predominant peri-follicular inflammatory cell type. In none of these PCA forms do we know exactly why hair follicles begin to attract such an infiltrate. Thus, it is not surprising that halting or even reversing this inflammation in PCA is often extremely difficult. However, increasing evidence suggests that healthy hair follicle epithelial stem cells enjoy relative protection from inflammatory assault by being located in an immunologically "privileged" niche. Because this protection may collapse in PCA, one key challenge in PCA research is to identify the specific signaling pathways that endanger, or restore, the relative immunoprotection of these stem cells. After a summary of pathobiological principles that underlie the development and clinical phenotype of PCA, we close by defining key open questions that need to be answered if more effective treatment modalities for this therapeutically very frustrating, but biologically fascinating, group of diseases are to be developed.
Article
Hair pigmentation is one of the most conspicuous phenotypes in humans. Melanocytes produce two distinct types of melanin pigment: brown to black, indolic eumelanin and yellow to reddish brown, sulfur-containing pheomelanin. Biochemically, the precursor tyrosine and the key enzyme tyrosinase and the tyrosinase-related proteins are involved in eumelanogenesis, while only the additional presence of cysteine is necessary for pheomelanogenesis. Other important proteins involved in melanogenesis include P protein, MATP protein, α-MSH, agouti signaling protein (ASIP), MC1R (the receptor for MSH and ASIP), and SLC7A11, a cystine transporter. Many studies have examined the effects of loss-of-function mutations of those proteins on mouse coat color pigmentation. In contrast, much less is known regarding the effects of mutations of the corresponding proteins on human hair pigmentation except for MC1R polymorphisms that lead to pheomelanogenesis. This perspective will discuss what we have/have not learned from mouse coat color pigmentation, with special emphasis on the significant roles of pH and the level of cysteine in melanosomes in controlling melanogenesis. Based on these data, a hypothesis is proposed to explain the diversity of human hair pigmentation.
Article
The pilosebaceous unit is a complex structure that undergoes a specific growth cycle and comprises a few important drug targeting sites. For example, drugs can be targeted to the bulge region with stem cells or to the sebaceous glands. Interest in pilosebaceous units is directed towards their utilization as reservoirs for localized therapy and also as a transport pathway for systemic drug delivery. Improved investigative methods, such as differential stripping, are being developed in order to determine follicular penetration. This article reviews relevant aspects of effective follicle-targeting formulations and delivery systems as well as the activity status of hair follicles, and variations in follicle size and distribution throughout various body regions. Each of these factors strongly affects follicular permeation. We provide examples of improved penetration of particle-based formulations and of a size-dependent manner of follicular penetration. Contradictions are also discussed, indicating the need for detailed future investigations.
Article
The hair-follicle bulge has recently been added to a growing list of human tissue compartments that exhibit a complex combination of immunosuppressive mechanisms, termed immune privilege (IP), which seem to restrict immune-mediated injury in specific locations. As epithelial hair-follicle stem cells (eHFSC) reside in the hair-follicle bulge region, it is conceivable that these IP mechanisms protect this vital compartment from immune-mediated damage, thereby ensuring the ongoing growth and cyclic regeneration of the hair follicle. Primary cicatricial alopecias (PCA) are a group of inflammatory hair disorders that result in hair-follicle destruction and permanent alopecia. Growing evidence suggests that eHFSC destruction is a key factor in the permanent follicle loss seen in these conditions. To explore the possible role of bulge IP collapse in PCA pathogenesis. We report three clinically distinct cases of PCA. Immunohistochemical analyses of paired biopsies from lesional and uninvolved scalp skin were compared using recognized markers of IP. Immunohistochemical investigation found increased expression of major histocompatibility complex (MHC) classes I and II and of beta2-microglobulin in the bulge region of lesional follicles compared with uninvolved follicles in each case. Further, expression of the bulge marker keratin 15 was reduced in lesional skin in two of the cases. This small series represents our first preliminary attempts to ascertain whether bulge IP collapse may play a role in PCA pathogenesis. We present standard parameters relating to hair-follicle IP in the bulge region of three patients with distinct PCA variants, and show the presence of features consistent with bulge IP collapse in each case.
Article
Please cite this paper as: Methods in hair research: how to objectively distinguish between anagen and catagen in human hair follicle organ culture. Experimental Dermatology 2010; 19: 305–312. Abstract: The organ culture of human scalp hair follicles (HFs) is the best currently available assay for hair research in the human system. In order to determine the hair growth-modulatory effects of agents in this assay, one critical read-out parameter is the assessment of whether the test agent has prolonged anagen duration or induced catagen in vitro. However, objective criteria to distinguish between anagen VI HFs and early catagen in human HF organ culture, two hair cycle stages with a deceptively similar morphology, remain to be established. Here, we develop, document and test an objective classification system that allows to distinguish between anagen VI and early catagen in organ-cultured human HFs, using both qualitative and quantitative parameters that can be generated by light microscopy or immunofluorescence. Seven qualitative classification criteria are defined that are based on assessing the morphology of the hair matrix, the dermal papilla and the distribution of pigmentary markers (melanin, gp100). These are complemented by ten quantitative parameters. We have tested this classification system by employing the clinically used topical hair growth inhibitor, eflornithine, and show that eflornithine indeed produces the expected premature catagen induction, as identified by the novel classification criteria reported here. Therefore, this classification system offers a standardized, objective and reproducible new experimental method to reliably distinguish between human anagen VI and early catagen HFs in organ culture.
Article
Primary cicatricial alopecias (PCA) represent uncommon inflammatory disorders that result in permanent loss of scalp hair. Cutaneous autoimmunity, most prominently chronic cutaneous lupus erythematosus (CCLE), can result in this kind of scarring hair loss. The cosmetic disfigurement caused by PCA and the very unsatisfactory therapeutic options available to date all demand a better understanding of the obscure pathobiology of PCA so as to define new therapeutic targets and strategies. Hair follicle (HF) cycling and regeneration are abolished in PCA due to irreversible, epithelial hair follicle stem cell (eHFSC) damage, triggered by major, yet unclear pro-inflammatory events (e.g. type I interferon-associated cytotoxic inflammation, loss of HF immune privilege, loss of immunosuppressive "no danger" signals). Therefore, immuno-protection of eHFSC and restitution of their immune privilege are attractive future therapeutic strategies in PCA. Chronic cutaneous lupus erythematosus-associated PCA may serve as a model system for other diseases where epithelial stem cells undergo immuno-destruction.
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This recently described entity begins in childhood and is characterized by actively growing hairs that can be easily and painlessly removed from the scalp, leading to alopecia.
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Immunostaining techniques were used to investigate the relationship between immune cells, proteoglycan, and class I MHC distribution in skin during the hair cycle in rats. The growth stage, anagen, was characterized by absence of class I MHC staining on most cells of the lower follicle and presence of chondroitin proteoglycan in the follicle sheath and dermal papilla. Immune cells were few in number and not associated with follicles. Dramatic changes were observed during regression in catagen; class I MHC was expressed on all follicle epithelium, large numbers of activated macrophages aggregated around the follicles, and the chondroitin proteoglycans disappeared from the follicle sheath and dermal papilla. During the resting stage, telogen, class I MHC remained on cells of the secondary germ, but macrophages and chondroitin proteoglycans were absent. These observations lead us to propose a hypothesis of immune privilege in hair growth.
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The Journal of Investigative Dermatology publishes basic and clinical research in cutaneous biology and skin disease.