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The Biology, Structure, and Function of Eyebrow Hair
Abstract
Eyebrow hair serves many important biologic and aesthetic functions. This article reviews the structure and function of the hair follicle, as well as hair follicle morphogenesis and cycling. Eyebrow hair follicles share the same basic structure as hair follicles elsewhere on the body, but are distinguished by their shorter anagen (growing) phase. Knowledge of the hair follicle structure and cycle is important for understanding the pathophysiology of alopecia, as diseases affecting the stem cell portion of the hair follicle in the bulge region may cause permanent hair loss. Furthermore, therapeutic agents that target distinct phases and hormones involved in the hair cycle may be useful for promoting hair growth.
J Drugs Dermatol. 2014;13(suppl 1):s12-s16.
... The eyebrow stays in the anagen phase for only 2 to 4 weeks, resulting in short hair. 12,13 Catagen is the regression phase of the hair follicles; it lasts 2 to 3 weeks. Apoptosis of follicular keratinocytes occurs during this phase and leads to the degeneration of the lower portion of hair follicles. ...
... At the end of the catagen phase, the dermal papilla moves upward and rests at the area close to the hair bulge. 13 Telogen is the resting phase of hair follicles; it lasts 2 to 3 months. Approximately 90% of eyebrow hairs are in the telogen phase. ...
... To start the new hair cycle, the dermal papilla stimulates follicular stem cells, known as the bulge activating theory, during late telogen, which leads to the re-entering of the anagen phase. 13 Distinguished hair shedding has been proposed as a separate phase called exogen. During this phase, the old hair is shed, and the new hair shaft grows. ...
Eyebrows serve as a key feature of the face and have many roles, including cosmetic appearance and social communication. Eyebrow hypotrichosis, which refers to reduction or absence of the eyebrow hair, could be a major problem that leads to negative functional, psychological, and social consequences. Bimatoprost is an ophthalmic prostamide analog that is approved by the United States Food and Drug Administration for the treatment of eyelash hypotrichosis. Its proposed mechanism is stimulation of the prostaglandin receptor in dermal papilla and melanocyte, thus leading to a prolonged anagen phase and increased melanogenesis. The hair follicle then increases in thickness, length, and darkness. The efficacy of bimatoprost for the treatment of eyebrow hypotrichosis has been supported by well-controlled studies. Bimatoprost, which is noninvasive, effective, and well tolerated, is worth considering as a treatment option for eyebrow hypotrichosis.
... The growth pattern and shape of the eyebrows are influenced by factors such as race, gender, and age [25]. Unlike scalp hair, eyebrow hair has a shorter growth phase, which results in its relatively shorter length [26]. ...
Supraorbital hollowness and pretarsal fullness, commonly known as the sunken eyelid and charming roll, respectively, are significant anatomical features that impact the aesthetic appearance of the periorbital region. Supraorbital hollowness is characterized by a recessed appearance of the upper eyelid, often attributed to genetic factors, aging, or surgical alterations, such as excessive fat removal during blepharoplasty. This condition is particularly prevalent among East Asians due to anatomical differences, such as weaker levator muscles and unique fat distribution patterns. Pretarsal fullness, also known as aegyo-sal, enhances the youthful and expressive appearance of the lower eyelid, forming a roll above the lash line that is considered aesthetically desirable in East Asian culture. Anatomical-based filler injection techniques are critical for correcting these features, involving precise placement within the correct tissue planes to avoid complications and achieve natural-looking results. This approach not only improves the aesthetic appeal of the eyelid but also enhances the overall facial harmony, emphasizing the importance of tailored procedures based on individual anatomy and cultural preferences.
... Hair coat, a unique skin keratinized organ in mammals, serves multiple functions such as temperature regulation, mechanical protection, and secondary sexual characteristics [1][2][3]. It is an important safeguard for animals to adapt to harsh environmental challenges. ...
Seasonal molting in mammals is a crucial survival strategy, yet the underlying molecular mechanisms have not been fully characterized. Melatonin, serving as a bridge for the transmission of photoperiod signals, plays a significant regulatory role in animals’ seasonal molting, and the physiological regulatory effects of melatonin signaling are highly dependent on the retinoic-acid-related orphan receptor alpha (Rorα). Hair follicle stem cells (HFSCs) are the most essential cell type in the process of hair follicle regeneration and seasonal replacement. Therefore, this study aims to discuss the regulatory effects of melatonin and its nuclear receptor RORA on HFSCs. This research found that RORA can downregulate cellular proliferation levels by inhibiting the cell cycle of HFSCs, while simultaneously promoting apoptosis in HFSCs and affecting the expression of some genes involved in ferroptosis. RORA can directly bind to the promoter regions of the cyclin genes Ccna2 and Ccne1 to regulate their transcription. Melatonin may enhance the viability of HFSCs by downregulating RORA levels. In this study, the impact of melatonin and its nuclear receptor RORA on the viability of HFSCs, along with some of the underlying molecular mechanisms, is characterized. These findings provide a theoretical foundation for research on the regulation of animal hair follicle development.
... Eyebrow hairs have a shorter growth cycle than scalp hair, which limits their length. The skin overlying the eyebrow region is influenced by the frontalis, orbicularis oculi, corrugator supercilii, and procerus muscles, which contribute to facial expressions and facilitate interpersonal communication (16). ...
This review explores the anatomical considerations and technical aspects of thread lifting for the forehead and eyebrow, focusing on the relationships between vascular structures, muscular anatomy, and age-related changes in the forehead-eyebrow complex. It highlights the critical importance of understanding neurovascular pathways, particularly the supratrochlear and supraorbital vessels, as well as the appropriate thread placement techniques necessary for optimal outcomes. The review demonstrates that I-shaped threads, when placed beneath the frontalis muscle, provide a safer and equally effective alternative to traditional U-shaped designs. Additionally, the review emphasizes the significance of preoperative assessment, especially the evaluation of tissue mobility and adhesion patterns, in predicting procedural success. The review concludes that combining thread lifting with volumising monofilaments offers a comprehensive approach to rejuvenating the forehead-glabellar region, while minimizing the risk of complications. This study’s clinical impact lies in its potential to enhance both the safety and efficacy of thread lifting procedures, offering practitioners a refined technique for esthetic rejuvenation of the forehead and eyebrow complex.
... In cases where scalp, eyebrow, or nose hairs are absent, patients become more susceptible to external harmful stimuli such as ultraviolet rays, sweat, dust, and infectious organisms. This vulnerability can lead to persistent physical discomfort and increase the risk of comorbidities such as conjunctivitis and upper respiratory tract infections [15][16][17] . ...
Background:
Alopecia areata (AA) is characterized by hair loss on the scalp and body, significantly impacting patients' quality of life based on its severity.
Objective:
This study aims to identify crucial factors influencing the perception of severe AA from the patients' viewpoint.
Methods:
A web-based survey was conducted among AA patients attending dermatology departments at 21 university hospitals in Korea. The survey comprised 17 criteria, exploring both clinical characteristics of AA patients and subjective determinants of disease severity.
Results:
A total of 791 AA patients and their caregivers participated in the survey. Approximately 30% of respondents developed AA during childhood, with 43.5% experiencing chronic courses lasting over 3 years. Half of the participants exhibited more than 20% scalp hair loss, and 42% reported additional hair loss on other body parts, such as eyelashes and nose hair. Most respondents agreed that patients with ≥20% scalp hair loss should be categorized as having severe AA. They also identified longer disease duration, involvement of non-scalp body hair, treatment refractoriness, and social or mental impairment requiring medical intervention as factors indicating increased disease severity.
Conclusion:
This survey underscores the significant impact of AA on patients' quality of life and highlights existing unmet needs in current treatment modalities.
... The eyebrow hair cycle is comprised no differently from other hairs of three phases (anagen, catagen and telogen) however with specific characteristics. Almost 10-15% of eyebrow follicles are in anagen phases which last from 15 to 30 days in average while the majority of follicles (85-90%) are in telogen phase which last for 60-90 days [4]. ...
Eyebrows are an important feature of facial identity and communications in human beings as well as an important eye defense shield from dust and foreign bodies. To compare the efficacy and safety between 0.01%, 0.03% bimatoprost and minoxidil 2% in gel formulations for eyebrow enhancement. Sixty eligible subjects were female or male, aged 18 years or older with eyebrow hypotrichosis, defined as either a Grade 1 or 2 on the Global Eyebrow Assessment (GEBA) scale. Patients were randomized into 3 groups using block randomization. Group a (20 patients) applied topical 0.03% bimatoprost gel once daily onto both eyebrows, group b (20 patients) applied topical 0.01% bimatoprost gel once daily onto both eyebrows while group c (20 patients) applied topical minoxidil 2% gel once daily onto both eyebrows. A significant improvement in GEBA score was reported in all the three groups after treatment ( P ≤ 0.001); however, there was no statistically significant difference between the three groups (P1 = 0.091; P2 = 0.102; P3 = 0.663). Bimatoprost is equally efficacious as minoxidil in enhancement of eyebrows with a more favorable response produced by the 0.03% concentration.
... The term is derived from the ancient Greek madaros, meaning bald. It can be incomplete or complete, unilateral or bilateral, and non-scarring or scarring, but above all, it is the marker of many congenital conditions and acquired diseases as well as a physiologic phenomenon due to age [1,2]. ...
Eyelashes and eyebrows have different functions, ranging from practical purposes such as protecting the eye apparatus from external hazards to the definition of our facial expression. For this reason, their loss could have both functional and psychological impact on patients' quality of life. Complete or partial loss can occur any time during life, and identifying the cause is mandatory to establish a correct and prompt treatment. The aim of this paper is to create a practical guide for the management of the most common causes of madarosis to the best of our knowledge.
... The life cycles of the eyebrows and eyelashes differ from other pilosebaceous units on the body, and understanding their unique physiology is essential to diagnosis and treatment of associated disease. Contrary to scalp hair follicles, which have anagen phases of 2-8 years, the anagen phase of eyebrows typically lasts for 2-3 months, catagen for 2-3 weeks, and telogen for 2-3 months [8,9]. Eyelashes also have a shorter life cycle of approximately 4-11 months [5]. ...
Madarosis is characterized by either complete or partial loss of eyebrow or eyelash hair. Etiologies for madarosis are varied, and accurate diagnosis is the first step in clinical management. Many studies have described findings related to specific causes of madarosis, but few have summarized the collective literature. The purpose of this review is to provide an updated overview on the symptomatology, diagnosis, trichoscopy findings, and treatment of eyebrow and eyelash alopecia.
... The importance of eyebrows, in general, is well established, and studies show that eyebrows are fundamentally important in emotional expression, communication, facial attractiveness, and facial recognition (Neely et al., 2014;Nguyen, 2014;Sadr et al., 2003). However, there are no studies that specifically investigate the importance of eyebrows to patients with AA. ...
Alopecia areata affects not only scalp hair but also other sites of body hair, including eyebrows. Our objective was to investigate the importance of eyebrows in the treatment goals of patients with alopecia areata. Through an online questionnaire, subjects were asked to assess satisfaction with the visually depicted level of response to treatment, using edited photographs depicting a range of eyebrows and scalp hair growth. The questionnaire was completed by 1,741 adults. Absent or partial growth of eyebrows and scalp hair elicited <25% satisfaction. Images depicting either complete eyebrows or complete scalp hair achieved satisfaction in >50% of participants. More participants were satisfied with complete eyebrows and no scalp hair (69%) than complete eyebrows and partial scalp hair (51%). Only when both eyebrows and scalp hair were completely regrown did extreme satisfaction levels reach 90.4%. Limitations include the online nature of the survey, lack of control group, and self-reported severity of alopecia areata in participants. These results suggest that eyebrows may be as important as scalp hair for patients assessing theoretical responses to treatment for alopecia areata. Future clinical studies should consider growth of eyebrows as an outcome measure on par with scalp hair growth.
... The final length of hairs is proportional to the duration of anagen. For example, human eyebrow hair follicles and eyelash hair follicles are short because the anagen phase of hair follicles of eyebrow is only 2-4 weeks and the anagen phase of eyelash hair follicles is 1-4 months, while scalp follicles grow long because they stay in anagen for 2-6 years (10,11). Except for rare congenital hair disorders and wound-induced "scarring" alopecia, most patients' hair disorders are related to aberrations in hair follicle cycling. ...
Prostanoids, including prostaglandins (PGs) and thromboxane A2 (TXA2), are a family of lipid-derived autacoids that modulate many physiological systems and pathological contexts. Prostanoids are generated by sequential metabolism of arachidonic acid, catalysed by cyclo-oxygenase, to PGH2, which is then converted to PGD2, PGE2, PGF2α, PGI2 and TXA2, catalysed by their specific synthases. Recent evidence suggests that prostanoids play a role in regulating hair growth. The PGF2α analogue is Food and Drug Administration-approved and routinely used to enhance the growth of human eyelashes. PGE2 is reported to protect from radiation-induced hair loss in mice. Conversely, PGD2 inhibits hair growth. This paper reviews the metabolism of prostanoids and the expression pattern of prostanoid receptors in hair follicles, focussing on their different and opposing effects on hair growth and the underlying mechanisms. This has potential clinical relevance in the treatment and prevention of hair disorders.
... 1,2) Hair basically have biological protective function from its external environments as well as influence social interaction. 3,4) Therefore, hair loss or baldness, correctively known as alopecia, directly distresses self-confidence affecting our daily life. 5) The growing and shape of hair fiber is strictly controlled and generated by the specialized mini-organ, hair follicle (HF) anchoring each hair into the skin. ...
Dermal papilla (DP) is a pivotal part of hair follicle, and the smaller size of the DP is related with the hair loss. In this study, we investigated the effect of titrated extract of Centella asiatica (TECA) on hair growth inductive property on 3D spheroid cultured human DP cells (HDP cells). Significantly increased effect of TECA on cell viability was only shown in 3D sphered HPD cells, not in 2D cultured HDP cells. Also, TECA treatment increased the sphere size of HDP cells. The luciferase activity of STAT reporter genes and the expression of STAT-targeted genes, SOCS1 and SOCS3, were significantly decreased. Also, TECA treatment increased the expression of the hair growth-related signature genes in 3D sphered HDP cells. Furthermore, TECA led to downregulation of the level of phosphorylated STAT proteins in 3D sphered HDP cells. Overall, TECA activates the potential of hair inductive capacity in HDP cells.
... Furthermore, the cycle's length varies within different parts of the body. For eyebrows, the cycle is completed in about four months (6), while it takes the scalp up to 6 years to finish. ...
Objective:
A preliminary study was conducted in 17 female volunteers (mean age 29.8 years) to gain deeper insights into the characteristics of terminal Caucasian female body hair of different body parts. The focus on Caucasian women was driven by the high number of different scalp hair phenotypes in this ethnicity and intended to identify relevant differences between body areas to improve body hair removal approaches.
Methods:
Multiple growth parameters and structural parameters were assessed for hair on the upper arm, forearm, upper leg, lower leg, axilla, and intimate area and compared to scalp data.
Results:
Especially macroscopic and much less microscopic or hair surface properties differ strikingly in the investigated body areas. Hair density on the body is much lower than on scalp with the highest hair density in the axilla and intimate area. Multi-hair follicular units are described for scalp but were also found to a smaller proportion in the axilla and the intimate area. Substantial percentates of hair triplets are only found on the scalp and intimate area. Hair diameter is highest in the intimate area, followed by axillary and lower leg hair and correlates with a faster hair growth rate. The angle of emerging hair is smallest in the intimate area, axilla and on the lower leg. Hair shafts on the lower leg and in the axilla have most overlapping cuticle layers, but independent of body region no significant differences in the mean thickness of cuticle layers was detectable. In addition, no differences were found in the mean distance between cuticle layer edges along the hair shaft and the hair surface roughness. Hair on the scalp, forearm, upper arm, and upper leg had an almost round shape, whereas hair of the lower leg, intimate area, and axilla had more elliptical shape. Hairs on the arm showed the highest luminance values and no visible medulla. The darkest hairs were in the axilla and intimate area containing the highest level of visible medulla in hair shafts.
Conclusion:
To our knowledge this is the first systematic study comparing terminal hair properties in all cosmetically relevant body regions in Caucasian women. This article is protected by copyright. All rights reserved.
Purpose: Space flights induce periocular facial changes which could contribute to ocular conditions which affect astronauts. This study is to validate parabolic flight as a suitable model for studying gravitational facial changes.
Methods: Healthy participants (n = 13; 37 ± 10 years) underwent short-term exposure to microgravity and hypergravity during parabolic flight. Facial images were captured and differences in measurements from pupil center to upper and lower eyelid margins (MRD1 and MRD2), and to the inferior and superior eyebrow margin (PTBi and PTBs) under normogravity, microgravity, and hypergravity were compared. A repeated measures ANOVA with Bonferroni-Holm corrected post-hoc paired t-test was used for statistical analysis.
Results: One hundred and twenty-seven images (44 normal gravity, 43 microgravity, 40 hypergravity) revealed that short-term microgravity induced a mean PTBi increase of 2.3 mm (p < 0.001) and mean PTBs increase of 2.4 mm (p < 0.001) while decreasing mean MRD2 by 0.9 mm (p < 0.001) but without change in MRD1 (p = 0.41). Short-term hypergravity did not change PTBs, PTBi or MRD2 but reduced mean MRD1 by 0.7 mm (p < 0.01).
Conclusions: Short-term microgravity, similar to spaceflight, significantly elevates PTB but not MRD1. It was also shown that MRD2 was reduced. Short-term hypergravity induces significant reductions only in MRD1. Phenomena are likely explicable by co-activation of the muscles raising the eyelid and eyebrow. Comparison to space data suggests that parabolic flight offers a valid model to study periocular facial changes in microgravity.
Background: Alopecia areata (AA) is an autoimmune disease affecting 2% of the global population, often causing localized scalp hair loss that can progress to alopecia totalis or universalis. While corticosteroids and JAK inhibitors are effective, their significant side effects highlight the need for safer, more targeted treatments. Recently, biologics have gained attention as potential treatments for AA. Methods: A review of clinical trials, case series, and case reports published on PubMed was conducted to assess the efficacy of cytokine-targeting biologics for the treatment of AA. Data on the mechanism of action, treatment outcomes, and safety were extracted and analyzed. Results: Cytokine-targeting biologics identified included Dupilumab, Secukinumab, Tralokinumab, Etanercept, Ustekinumab, Infliximab, Adalimumab, and Tildrakizumab. Dupilumab and ustekinumab demonstrated strong efficacy, with dupilumab showing significant regrowth in 89% of cases and ustekinumab in all patients. Tralokinumab demonstrated a 33.75% improvement, with no patients achieving SALT50. Limited efficacy was observed with secukinumab, tildrakizumab, and adalimumab, with 71.4%, 77.8%, and 50% of patients, respectively, showing no response. Disease worsening was observed in patients who received etanercept (29%) and infliximab (50%). Conclusions: Further research is necessary to optimize treatment protocols, identify predictive biomarkers, and, crucially, discover novel and more effective cytokine targets to advance biologics as a cornerstone therapy for AA.
Background
Eyebrows significantly influence facial aesthetics and are often linked to attractiveness and personality. Eyebrow loss and alopecia impact physical and psychological well‐being. Several treatments, including mesotherapy (MT), aim to enhance eyebrow density and quality. Despite the availability of MT for hair growth, its application in eyebrow revitalization is less explored.
Aims
This study evaluates clients' perceptions and satisfaction with eyebrow MT (EB MT) using AQ skin solutions' growth factor‐based MT cocktail serum.
Patients/Methods
Thirty‐two healthy women (ages 21–55) with thin or weakened eyebrows underwent three EB MT sessions spaced 2–4 weeks apart. Exclusion criteria included chronic diseases, allergies, and conditions like pregnancy. Each session lasted about 40 min, and “point by point” and “nappage” techniques were employed. Satisfaction and pain levels were assessed through a Numeric Rating Scale for Satisfaction (NRSS) and Pain scale, while photographic analysis and the Global Aesthetic Improvement Scale (GAIS) evaluated effectiveness.
Results
The average GAIS score was 8.28, while the NRSS satisfaction score was 8.06. Pain levels were moderately low, averaging 4.0. A high majority (90.6%) were satisfied and willing to continue treatment, with 100% recommending EB MT to others. Notable improvements in overall appearance were reported by participants.
Conclusions
EB MT demonstrated high satisfaction and low pain levels, with significant improvements in eyebrow density and appearance. This treatment is a practical option for eyebrow enhancement with a strong safety profile, motivating further clinical application.
Background
The ALLEGRO phase 2a and 2b/3 studies demonstrated that ritlecitinib is efficacious and well tolerated in adult and adolescent patients with alopecia areata (AA) up to 48 weeks.
Objective
The efficacy of ritlecitinib through Month 24 and safety through data cutoff were assessed in the ALLEGRO phase 2b/3 study and the ongoing long-term, open-label, phase 3 ALLEGRO-LT study.
Methods
Patients aged ≥12 years with AA and ≥50% scalp hair loss from ALLEGRO-2b/3 who rolled over to ALLEGRO-LT after up to 48 weeks were included. Proportions of patients with responses based on clinician-reported Severity of Alopecia Tool (SALT) score of ≤20 and ≤10, eyebrow assessment (EBA) and eyelash assessment (ELA), patient global impression of change (PGI-C) and patient satisfaction with hair growth are reported through Month 24 for patients who received ritlecitinib 50 mg daily with or without a 200-mg 4-week daily loading dose. Observed and imputed data (last observation carried forward [LOCF]) were reported until December 9, 2022. Safety was assessed throughout.
Results
At Month 12, SALT score ≤20 was achieved by 45.1% and 45.9% (observed) and 40.3% and 41.8% (LOCF) of the 191 and 194 patients who received ritlecitinib 50 mg and ritlecitinib 200/50 mg, respectively. At Month 24, proportions increased to 60.8% and 63.1% (observed) and 46.1% and 50.8% (LOCF), respectively. Patients with abnormal EBA or ELA scores at baseline achieved responses at Month 24 (EBA observed: 57.6% [50 mg], 61.0% [200/50 mg]; EBA LOCF: 46.8% [50 mg], 50.9% [200/50 mg]; ELA observed: 51.2% [50 mg], 62.7% [200/50 mg]; ELA LOCF: 43.2% [50 mg], 51.7% [200/50 mg]). PGI-C response was achieved by patients at Month 24 (observed: 70.0% [50 mg], 76.4% [200/50 mg]; LOCF: 56.6% [50 mg], 65.5% [200/50 mg]). Safety profiles for both treatment groups were consistent with the known safety profile of ritlecitinib.
Conclusion
Ritlecitinib has clinically meaningful and sustained efficacy beyond 1 year with a favourable safety and tolerability profile, supporting its long-term use in patients aged ≥12 years with AA.
Trial Registries
ClinicalTrials.gov: NCT03732807, NCT04006457
To adapt to the extreme conditions of plateau environments, yaks have evolved thick hair, making them an ideal model for investigating the mechanisms involved in hair growth. We can gain valuable insights into how hair follicles develop and their cyclic growth in challenging environments by studying yaks. However, the lack of essential data on yak hair follicle histology and the absence of in vitro cell models for hair follicles serve as a limitation to such research objectives. In this study, we investigated the structure of skin tissue during different hair follicle cycles using the yak model. Additionally, we successfully established in vitro models of hair follicle-associated cells derived from yak skin, including dermal papilla cells (DPCs), preadipocytes, and fibroblasts. We optimized the microdissection technique for DPCs culture by simplifying the procedure and reducing the time required. Furthermore, we improved the methodology used to differentiate yak preadipocytes into mature adipocytes, thus increasing the differentiation efficiency. The introduction of yak as a natural model provides valuable research resources for exploring the mechanisms of hair growth and contributes to a deeper understanding of hair follicle biology and the development of regenerative medicine strategies.
Human hair is a natural fiber with keratin and keratin-related proteins as a main component. Externally, hair is a thin, pliable tube of dead, fully keratinized epithelial cells, while inside the skin, it is part of a single living hair follicle. In addition to a large amount of protein, hair also contains low levels of lipids and pigments. The hair also has its own ecological balance system. Although the lipid content in hair is much lower than the protein content, it plays an important role in hair and influences hair texture to some extent. For example, prevent hair breakage and thinning; To act as a barrier to moisture loss; and improve the gloss, elasticity and tensile strength of the hair stem. Environment, hair dressing and daily care can all cause hair damage to varying degrees. Factors such as ultraviolet light and chemicals can make hair dry, rough, dull, stiff and brittle by destroying the proteins, pigment sand lipid sin the hair. In this paper, the composition, classification and influencing factors of hair were reviewed. The composition and function of lipids in hair were investigated emphatically. It aims to improve people's understanding of the physical and chemical properties and structure of hair. It provides reference value for the research and development of hair cosmetics for different hair states and washing purposes. The function of hair lipids on hair is not accurate. In addition, there is still some controversy on the existing role of hair lipids, which needs further research.
Abstrak Kemiri dan Bawang Putih adalah tanaman yang memiliki efek pada pertumbuhan rambut. Bahan kimia yang terkandung dalam tanaman kaya akan nutrisi yang dibutuhkan untuk pertumbuhan rambut atau alis seperti alkaloid, saponin, sterol / terpenoid. Khasiat minyak kemiri dan minyak bawang putih dengan tiga konsentrasi 1000 ppm, 500 ppm dan 100 ppm diuji aktivitasnya sebagai pupuk bulu kelinci dengan menerapkan minyak kemiri dan minyak bawang putih masing-masing sekitar 1 ml di tempat disiapkan dua kali sehari selama 28 hari. minyak kemiri dan minyak bawang putih diukur dengan mengukur panjang, berat dan diameter bulu kelinci. Hasil uji aktivitas ketiga konsentrasi ini menguji data dengan statistik dan mendapatkan hasil yang paling optimal karena penanam bulu kelinci adalah minyak kemiri dengan konsentrasi 1000 ppm dengan rata-rata pertumbuhan panjang selama 28 hari adalah 0,6250 cm dan minyak bawang putih dengan konsentrasi 500 ppm dengan panjang rata-rata pertumbuhan selama 28 hari adalah 0,8417 cm, sedangkan untuk bobot bulu kelinci paling optimal adalah dengan konsentrasi bawang putih 1000 ppm dengan berat rata-rata 28 hari adalah 0,3627 g, sedangkan pertumbuhan kelinci Bobot bulu paling optimal selama 28 hari adalah kemiri 1000 ppm dengan berat rata-rata selama 28 hari = 0,3518 g hasil analisis signifikan pada (p≤0,05). Hasil analisis paling optimal dikombinasikan untuk melihat sinergi antara kedua jenis oli. Kemanjuran yang paling signifikan dari minyak kemiri dan minyak bawang putih adalah kombinasi dengan rasio minyak kemiri dan bawang putih adalah 1: 1 dengan konsentrasi (200: 200) ppm. Kata kunci: Kombinasi, Ekstrak, Kemiri, Bawang putih
Dermoscopy is becoming an indispensable tool in everyday practice, with an expanding range of applications. Trichoscopy is effective not only in establishing the diagnosis of scalp disorders but also in the follow‐up of treatment. The MEDLINE database was searched using the terms “dermoscopy” and “trichoscopy” in combination with each of the following: “axilla,” “pubic area,” “beard,” “eyebrows,” “eyelashes,” and “body hairs.” We included case reports, case series, and review articles mentioning the previous terms. By providing an updated review from the literature, we aimed to emphasize the potential uses of trichoscopy in detecting diseases in hairy locations other than the scalp. Various inflammatory conditions, infections, and infestations are discussed.
It has long been known that there is a special affinity of psoriasis for the scalp: Here, it occurs most frequently, lesions terminate sharply in frontal skin beyond the hair line and are difficult to treat. Yet, surprisingly, scalp psoriasis only rarely causes alopecia, even though the pilosebaceous unit clearly is affected. Here, we systematically explore the peculiar, insufficiently investigated connection between psoriasis and growing (anagen) terminal scalp hair follicles (HFs), with emphasis on shared regulatory mechanism and therapeutic targets. Interestingly, several drugs and stressors that can trigger/aggravate psoriasis can inhibit hair growth (e.g. beta-blockers, chloroquine, carbamazepine, interferon-alpha, perceived stress). Instead, several anti-psoriatic agents can stimulate hair growth (e.g., cyclosporine, glucocorticoids, dithranol, UV irradiation), while skin/HF trauma (Köbner phenomenon/depilation) favors the development of psoriatic lesions and induces anagen in “quiescent” (telogen) HFs.
On this basis, we propose two interconnected working models: a) the existence of a bidirectional “hair follicle-psoriasis axis”, along which keratinocytes of anagen scalp HFs secrete signals that favor the development and maintenance of psoriatic scalp lesions and respond to signals from these lesions, and b) that anagen induction and psoriatic lesions share molecular “switch-on” mechanisms, which invite pharmacological targeting, once identified. Therefore, we advocate a novel, cross-fertilizing and integrative approach to psoriasis and hair research that systematically characterizes the “HF-psoriasis axis”, focused on identification and therapeutic targeting of selected, shared signaling pathways in the future management of both, psoriasis and hair growth disorders.
Background:
Differences in growth patterns among the various parts of the eyebrow have been observed.
Aims:
We aimed to investigate changes in the hair density and diameter and analyze the eyebrow growth pattern of each eyebrow part (head, body, and tail) in patients with eyebrow hypotrichosis over a 24-week course of topical treatment.
Patients/methods:
A retrospective study of 48 patients who received treatment with bimatoprost 0.01% was conducted. Patient demographic data were collected; measurements of hair density and diameter in the different parts of the eyebrow were collected and statistically evaluated.
Results:
The tail of the eyebrow revealed the lowest baseline eyebrow density and diameter. Significant changes in eyebrow density (P = .01) and diameter (P = .01) were first detected in the tail at 4 and 16 weeks of treatment, respectively. The head and body showed a comparable growth pattern.
Conclusions:
This study confirms the previous observations that hair density, diameter, pattern of growth, and hair growth cycle vary according to their anatomical location within the eyebrow. A better understanding of eyebrow growth pattern could provide the precise pathomechanism of eyebrow hypotrichosis leading to a standardized treatment protocol.
Background:
Previous studies have proven the efficacy and safety of 0.01% and 0.03% bimatoprost for the treatment of eyebrow hypotrichosis; however, there is no comparison study between both concentrations.
Aims:
To compare the efficacy and safety between 0.01% and 0.03% bimatoprost for the treatment of eyebrow hypotrichosis.
Patients/methods:
This prospective, randomized, double-blind, split-face clinical study was conducted in 30 patients with eyebrow hypotrichosis. Each side of eyebrow of individual patients was randomly assigned for 0.01% and 0.03% bimatoprost, applied on each eyebrow once daily. Eyebrow density, diameter, the Global Eyebrow Assessment scale, 7-point rating scale, and patient satisfaction were evaluated. Side effects were also recorded.
Results:
Both 0.01% and 0.03% bimatoprost significantly improved eyebrow density and diameter (P < .05), although there were no statistically significant differences in changes in eyebrow density and diameter from baseline between both concentrations (P = .96 and .84, respectively). Additionally, patients significantly preferred 0.03% bimatoprost in terms of clinical improvement and satisfaction (P = .04 and .003, respectively).
Conclusions:
Both 0.01% and 0.03% bimatoprost are effective and safe for the treatment of eyebrow hypotrichosis. Bimatoprost 0.03% is superior to its 0.01% counterpart, albeit without statistical significance.
Eyebrows serve a key role in eye protection, communication, and self-expression. Trends in eyebrow grooming are constantly evolving, often requiring plucking, waxing, or laser hair removal to style. When combined with the natural thinning of the brow with aging, the result can be a sparse or even absent eyebrow hair over time. Follicular unit transplantation provides a means of restoring eyebrow fullness and architecture. With careful attention and augmentation of follicle transfer techniques, a natural end result is possible.
© 2015 Wiley Periodicals, Inc.
Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) influence hair follicles through paracrine and intracrine routes. There is significant evidence that PTH and PTHrP influence the proliferation and differentiation of hair follicle cells. The PTH/PTHrP receptor signalling plays an important role in the hair follicle cycle and may induce premature catagen-telogen transition. Transgenic mice with an overexpression or blockade (PTH/PTHrP receptor knockout mice) of PTHrP activity revealed impaired or increased hair growth, respectively. Some findings also suggest that PTHrP may additionally influence the hair cycle by inhibiting angiogenesis. Antagonists of the PTH/PTHrP receptor have been shown to stimulate proliferation of hair follicle cells and hair growth. A hair-stimulating effect of a PTH/PTHrP receptor antagonist applied topically to the skin has been observed in hairless mice, as well as in mice treated with cyclophosphamide. These data indicate that the PTH/PTHrP receptor may serve as a potential target for new (topical) hair growth-stimulating drugs, especially for chemotherapy-induced alopecia. © 2015 S. Karger AG, Basel.
β-Catenin, a key transducer molecule of Wnt signaling, is required for adult hair follicle growth and regeneration. However, the cellular source of Wnt ligands required for Wnt/β-catenin activation during anagen induction is unknown. In this study, we genetically deleted Wntless (Wls), a gene required for Wnt ligand secretion by Wnt-producing cells, specifically in the hair follicle epithelium during telogen phase. We show that epithelial Wnt ligands are required for anagen, as loss of Wls in the follicular epithelium resulted in a profound hair cycle arrest. Both the follicular epithelium and dermal papilla showed markedly decreased Wnt/β-catenin signaling during anagen induction compared with control hair follicles. Surprisingly, hair follicle stem cells that are responsible for hair regeneration maintained expression of stem cell markers but exhibited significantly reduced proliferation. Finally, we demonstrate that epidermal Wnt ligands are critical for adult wound-induced de novo hair formation. Collectively, these data show that Wnt ligands secreted by the hair follicle epithelium are required for adult hair follicle regeneration and provide new insight into potential cellular targets for the treatment of hair disorders such as alopecia.Journal of Investigative Dermatology advance online publication, 19 July 2012; doi:10.1038/jid.2012.230.
The discovery of long-lived epithelial stem cells in the bulge region of the hair follicle led to the hypothesis that epidermal renewal and epidermal repair after wounding both depend on these cells. To determine whether bulge cells are necessary for epidermal renewal, here we have ablated these cells by targeting them with a suicide gene encoding herpes simplex virus thymidine kinase (HSV-TK) using a Keratin 1-15 (Krt1-15) promoter. We show that ablation leads to complete loss of hair follicles but survival of the epidermis. Through fate-mapping experiments, we find that stem cells in the hair follicle bulge do not normally contribute cells to the epidermis which is organized into epidermal proliferative units, as previously predicted. After epidermal injury, however, cells from the bulge are recruited into the epidermis and migrate in a linear manner toward the center of the wound, ultimately forming a marked radial pattern. Notably, although the bulge-derived cells acquire an epidermal phenotype, most are eliminated from the epidermis over several weeks, indicating that bulge stem cells respond rapidly to epidermal wounding by generating short-lived 'transient amplifying' cells responsible for acute wound repair. Our findings have implications for both gene therapy and developing treatments for wounds because it will be necessary to consider epidermal and hair follicle stem cells as distinct populations.
The adult hair follicle houses stem cells that govern the cyclical growth and differentiation of multiple cell types that collectively produce a pigmented hair. Recent studies have revealed that hair follicle stem cells are heterogeneous and dynamic throughout the hair cycle. Moreover, interactions between heterologous stem cells, including both epithelial and melanocyte stem cells, within the hair follicle are just now being explored. This review will describe how recent findings have expanded our understanding of the development, organization, and regeneration of hair follicle stem cells. At a basic level, this review is intended to help construct a reference point to integrate the surge of studies on the molecular mechanisms that regulate these cells.
Wnt/beta-catenin and NF-kappaB signaling mechanisms provide central controls in development and disease, but how these pathways intersect is unclear. Using hair follicle induction as a model system, we show that patterning of dermal Wnt/beta-catenin signaling requires epithelial beta-catenin activity. We find that Wnt/beta-catenin signaling is absolutely required for NF-kappaB activation, and that Edar is a direct Wnt target gene. Wnt/beta-catenin signaling is initially activated independently of EDA/EDAR/NF-kappaB activity in primary hair follicle primordia. However, Eda/Edar/NF-kappaB signaling is required to refine the pattern of Wnt/beta-catenin activity, and to maintain this activity at later stages of placode development. We show that maintenance of localized expression of Wnt10b and Wnt10a requires NF-kappaB signaling, providing a molecular explanation for the latter observation, and identify Wnt10b as a direct NF-kappaB target. These data reveal a complex interplay and interdependence of Wnt/beta-catenin and EDA/EDAR/NF-kappaB signaling pathways in initiation and maintenance of primary hair follicle placodes.
The mammalian hair follicle is a treasure waiting to be discovered by more molecular geneticists. How can a tiny cluster of apparently uniform epithelial cells, adjacent to a tiny cluster of uniform mesenchymal cells, give rise to five or six concentric cylinders, each of which is composed of cells of a distinctive type that synthesize their own distinctive set of proteins? There is now evidence that several growth factors, cell adhesion molecules and other molecules play important roles in the regulation of this minute organ.
Inconsistent with the view that hair follicle stem cells reside in the matrix area of the hair bulb, we found that label-retaining cells exist exclusively in the bulge area of the mouse hair follicle. The bulge consists of a subpopulation of outer root sheath cells located in the midportion of the follicle at the arrector pili muscle attachment site. Keratinocytes in the bulge area are relatively undifferentiated ultrastructurally. They are normally slow cycling, but can be stimulated to proliferate transiently by TPA. Located in a well-protected and nourished environment, these cells mark the lower end of the "permanent" portion of the follicle. Our findings, plus a reevaluation of the literature, suggest that follicular stem cells reside in the bulge region, instead of the lower bulb. This new view provides insights into hair cycle control and the possible involvement of hair follicle stem cells in skin carcinogenesis.
The opening of intracellular potassium channels is a common mechanism of action for a set of anti-hypertensive drugs that includes the hair-growth-inducing agent minoxidil. Recent work suggests potassium channel openers (PCOs) also influence hair growth. Correlative studies demonstrate that a series of PCOs including minoxidil, pinacidil, P-1075, an active pinacidil analog, RP-49,356, cromakalim, and nicorandil maintain hair growth in cultured vibrissa follicles. Studies using balding stumptail macaques verify that minoxidil, P-1075, and cromakalim but not RP-49,356 stimulate hair growth. The definition of potassium channels and documentation of drug effects on these channels is classically done using electrophysiologic techniques. Such studies require the identification and isolation of target cells. Both these are among the unsolved problems in the area of hair biology. Estimating K+ flux using 86Rb+ as a K+ tracer is an accepted method of assessing potassium channel conductance in other organ systems. Both pinacidil and RP-49,356 induce measurable Rb+ flux in isolated vibrissa follicles and a hair epithelial cell line whereas neither minoxidil nor minoxidil sulfate had measurable effects. Potassium channels have been studied successfully in other organ systems using specific pharmacologic blockers for the various channel subtypes. Blockers including glyburide, tetraethylammonium, and procaine failed to inhibit minoxidil stimulation of cultured follicles. The current explosion of knowledge on potassium channel biology, cloning of channels, and continued progress in hair biology promise to clarify the role of K+ ions in the control of hair follicles.
Clinical conditions causing hair loss, such as androgenetic alopecia, alopecia areata, and scarring alopecia, can be psychologically devastating to individuals and are the target of a multimillion dollar pharmaceutical industry. The importance of the hair follicle in skin biology, however, does not rest solely with its ability to produce hair. Hair follicles are self-renewing and contain reservoirs of multipotent stem cells that are capable of regenerating the epidermis and are thought to be utilized in wound healing. Hair follicles are also the sites of origin of many neoplasias, including some basal cell carcinomas and pilomatricoma. These diseases result from inappropriate activation of signaling pathways that regulate hair follicle morphogenesis. Identification of the signaling molecules and pathways operating in developing and postnatal, cycling, hair follicles is therefore vital to our understanding of pathogenic states in the skin and may ultimately permit the development of novel therapies for skin tumors as well as for hair loss disease. The purpose of this review is to summarize recent progress in our understanding of the molecular mechanisms regulating hair follicle formation, and to discuss ways in which this information may eventually be utilized in the clinic.
Minoxidil has been widely used to treat androgenetic alopecia, but little is known about its pharmacological activity or about the identity of its target cells in hair follicles. We hypothesized that minoxidil has direct effects on the proliferation and apoptosis of dermal papilla cells (DPCs) of human hair follicle.
To elucidate the mechanism of topical minoxidil action in terms of stimulating hair growth.
We evaluated cell proliferations in cultured DPCs by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and measured the expressions of extracellular signal-regulated kinase (ERK), Akt, Bcl-2, and Bax by Western blot. We also measured elongation of hair follicles in organ culture.
Minoxidil significantly increased the proliferation of DPCs. The levels of ERK phosphorylation and of phosphorylated Akt increased significantly 1 h post-treatment; percentage increase of ERK phosphorylation was 287% at 0.1 microM and 351% at 1.0 microM of minoxidil, and that of Akt phosphorylation was 168% at 0.1 microM and 257% at 1.0 microM of minoxidil. 1.0 microM of minoxidil increased Bcl-2 expression over 150%, while 1.0 microM of minoxidil decreased Bax expression by more than 50%. Moreover, a significant elongation of individual hair follicles in organ culture was observed after adding minoxidil.
Minoxidil promotes the survival of human DPCs by activating both ERK and Akt and by preventing cell death by increasing the ratio of Bcl-2/Bax. We suggest that minoxidil stimulates the growth of human hairs by prolonging anagen through these proliferative and anti-apoptotic effects on DPCs.
The lowermost portion of the resting (telogen) follicle consists of the bulge and secondary hair germ. We previously showed that the progeny of stem cells in the bulge form the lower follicle and hair, but the relationship of the bulge cells with the secondary hair germ cells, which are also involved in the generation of the new hair at the onset of the hair growth cycle (anagen), remains unclear. Here we address whether secondary hair germ cells are derived directly from epithelial stem cells in the adjacent bulge or whether they arise from cells within the lower follicle that survive the degenerative phase of the hair cycle (catagen). We use 5-bromo-2'-deoxyuridine to label bulge cells at anagen onset, and demonstrate that the lowermost portion of the bulge collapses around the hair and forms the secondary hair germ during late catagen. During the first six days of anagen onset bulge cells proliferate and self-renew. Bulge cell proliferation at this time also generates cells that form the future secondary germ. As bulge cells form the secondary germ cells at the end of catagen, they lose expression of a biochemical marker, S100A6. Remarkably, however, following injury of bulge cells by hair depilation, progenitor cells in the secondary hair germ repopulate the bulge and re-express bulge cell markers. These findings support the notion that keratinocytes can "dedifferentiate" to a stem cell state in response to wounding, perhaps related to signals from the stem cell niche. Finally, we also present evidence that quiescent bulge cells undergo apoptosis during follicle remodeling in catagen, indicating that a subpopulation of bulge cells is not permanent.
Substantial progress has been made regarding the elucidation of differentiation processes of the human hair follicle. This review first describes the genomic organization of the human hair keratin gene family and the complex expression characteristics of hair keratins in the hair-forming compartment. Sections describe the role and fate of hair keratins in the diseased hair follicle, particularly hereditary disorders and hair follicle-derived tumors. Also included is a report on the actual state of knowledge concerning the regulation of hair keratin expression. In the second part of this review, essentially the same principles are applied to outline more recent and, thus, occasionally fewer data on specialized epithelial keratins expressed in various tissue constituents of the external sheaths and the companion layer of the follicle. A closing outlook highlights issues that need to be explored further to deepen our insight into the biology and genetics of the hair follicle.
Hair follicle stem cells sustain growth and cycling of the hair follicle and are located in the permanent portion of the follicle known as the bulge. In this issue of the JCI, Ohyama et al. report the characterization of global gene expression patterns of human hair follicle stem cells after their isolation using sophisticated laser capture techniques to microdissect out bulge cells. They discovered a panel of cell surface markers useful for isolating living hair follicle stem cells, a finding with potential therapeutic implications since isolated stem cells in mice can generate new hair follicles when transplanted to other mice. The findings of Ohyama et al. validate the use of the mouse for studying hair follicle biology but also underscore critical differences between mouse and human stem cell markers. In particular, CD34, which delineates hair follicle stem cells in the mouse, is not expressed by human hair follicle stem cells, while CD200 is expressed by stem cells in both species. Ultimately, this information will assist efforts to develop cell-based and cell-targeted treatments for skin disease.
Putative epithelial stem cells were identified in the hair follicle bulge as quiescent "label retaining cells". The study of these cells was hindered until the identification of bulge cell molecular markers, such as CD34 expression and K15 promoter activity. This allowed for the isolation and characterization of bulge cells from mouse follicles. Bulge cells possess stem cell characteristics, including multipotency, high proliferative potential, and their cardinal feature of quiescence. Lineage analysis demonstrated that all epithelial layers within the adult follicle and hair originated from bulge cells. Bulge cells only contribute to the epidermis during wound healing, but after isolation, when combined with neonatal dermal cells, they regenerate new hair follicles, epidermis, and sebaceous glands. Bulge cells maintain their stem cell characteristics after propagation in vitro, thus ultimately they may be useful for tissue engineering applications. Understanding the signals important for directing movement and differentiation of bulge cells into different lineages will be important for developing treatments based on stem cells as well as clarifying their role in skin disease.
Drugs may cause hair loss, stimulate hair growth, or induce changes in the hair shape and color. Drug-induced hair loss is, in most cases, a consequence of a toxic effect of the drug on the hair matrix. Although a large number of drugs have been occasionally reported to produce hair loss, the relationship between drug intake and hair loss has been proven only for a few agents. Type of hair loss (telogen effluvium, anagen effluvium, or both) depends on the drug, its dosage, and patient's susceptibility. Drug-induced hair loss is usually reversible.