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International Journal of Molecular... Jul 2020The hair cycle and hair follicle structure are highly affected by various hormones. Androgens-such as testosterone (T); dihydrotestosterone (DHT); and their prohormones,... (Review)
Review
The hair cycle and hair follicle structure are highly affected by various hormones. Androgens-such as testosterone (T); dihydrotestosterone (DHT); and their prohormones, dehydroepiandrosterone sulfate (DHEAS) and androstendione (A)-are the key factors in terminal hair growth. They act on sex-specific areas of the body, converting small, straight, fair vellus hairs into larger darker terminal hairs. They bind to intracellular androgen receptors in the dermal papilla cells of the hair follicle. The majority of hair follicles also require the intracellular enzyme 5-alpha reductase to convert testosterone into DHT. Apart from androgens, the role of other hormones is also currently being researched-e.g., estradiol can significantly alter the hair follicle growth and cycle by binding to estrogen receptors and influencing aromatase activity, which is responsible for converting androgen into estrogen (E2). Progesterone, at the level of the hair follicle, decreases the conversion of testosterone into DHT. The influence of prolactin (PRL) on hair growth has also been intensively investigated, and PRL and PRL receptors were detected in human scalp skin. Our review includes results from many analyses and provides a comprehensive up-to-date understanding of the subject of the effects of hormonal changes on the hair follicle.
Topics: Androgens; Estradiol; Female; Hair Follicle; Humans; Male; Prolactin; Sex Characteristics
PubMed: 32731328
DOI: 10.3390/ijms21155342 -
Nature Sep 2017The melanocortin-1 receptor (MC1R), a G-protein-coupled receptor, has a crucial role in human and mouse pigmentation. Activation of MC1R in melanocytes by...
The melanocortin-1 receptor (MC1R), a G-protein-coupled receptor, has a crucial role in human and mouse pigmentation. Activation of MC1R in melanocytes by α-melanocyte-stimulating hormone (α-MSH) stimulates cAMP signalling and melanin production and enhances DNA repair after ultraviolet irradiation. Individuals carrying MC1R variants, especially those associated with red hair colour, fair skin and poor tanning ability (denoted as RHC variants), are associated with higher risk of melanoma. However, how MC1R activity is modulated by ultraviolet irradiation, why individuals with red hair are more prone to developing melanoma, and whether the activity of RHC variants might be restored for therapeutic benefit are unknown. Here we demonstrate a potential MC1R-targeted intervention strategy in mice to rescue loss-of-function MC1R in MC1R RHC variants for therapeutic benefit by activating MC1R protein palmitoylation. MC1R palmitoylation, primarily mediated by the protein-acyl transferase ZDHHC13, is essential for activating MC1R signalling, which triggers increased pigmentation, ultraviolet-B-induced G1-like cell cycle arrest and control of senescence and melanomagenesis in vitro and in vivo. Using C57BL/6J-Mc1rJ mice, in which endogenous MC1R is prematurely terminated, expressing Mc1r RHC variants, we show that pharmacological activation of palmitoylation rescues the defects of Mc1r RHC variants and prevents melanomagenesis. The results highlight a central role for MC1R palmitoylation in pigmentation and protection against melanoma.
Topics: Acyltransferases; Animals; Cell Transformation, Neoplastic; Female; Humans; Lipoylation; Male; Melanocytes; Melanoma; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Pigmentation; Receptor, Melanocortin, Type 1
PubMed: 28869973
DOI: 10.1038/nature23887 -
Dermatology Practical & Conceptual 2020Unwanted hair growth, which is a common aesthetic problem, has traditionally been treated using various techniques such as shaving, waxing, and epilation, but most of...
Unwanted hair growth, which is a common aesthetic problem, has traditionally been treated using various techniques such as shaving, waxing, and epilation, but most of these provide only a temporary solution. Laser and light-based technology for hair removal has become one of the fastest growing procedures in modern cosmetic dermatology in the last decade. Clinical experience suggests that in the ideal subject with fair skin and dark hair, laser treatment can reduce hair growth significantly. This article reviews the various laser and light-based devices used for hair removal along with the various laser and patient parameters that affect the outcome of laser treatment for hair removal. Photoepilation, when properly used, offers clear advantages when compared with older, traditional techniques.
PubMed: 32363110
DOI: 10.5826/dpc.1002a48 -
Archives of Plastic Surgery Nov 2022The scar alopecia after cranioplasty (SAC) may decrease the patient's quality of life. We have treated SAC using follicular unit extraction (FUE). The aim of this...
The scar alopecia after cranioplasty (SAC) may decrease the patient's quality of life. We have treated SAC using follicular unit extraction (FUE). The aim of this study was to discuss that efficacy of FUE and how much hair follicular unit (FU) should be transplanted intraoperatively for the treatment of SAC. We treated 10 patients (4 men and 6 women) who had SAC using FUE. The average age, alopecia size, and intraoperative hair density on the graft area were 29.8 ± 12.1 years, 29.8 ± 44.5 cm , and 34.6 ± 11.8 FU/cm , respectively. One year postoperatively, the average hair survival rate on the graft area was 66.3 ± 6.1%. Hair appearance was rated as good in six, fair in three, and poor in one. Among patients whose 1-year postoperative hair density was ≥ 20 FU/cm , five of six patients achieved good results. However, among patients whose 1-year postoperative hair density was < 20 FU/cm , all four patients achieved fair or poor results. The postoperative hair density was significantly higher in patients whose 1-year postoperative hair density was ≥ 20 FU/cm than in patients whose 1-year postoperative hair density was < 20 FU/cm . The rate of achieving fair or poor results was significantly higher if the postoperative hair density was < 20 FU/cm than if it was ≥ 20 FU/cm ( = 0.047). FU excision is useful for the treatment of scar alopecia after craniotomy. Our results suggest that the 1-year postoperative hair density should exceed 20 FU/cm to achieve good outcomes.
PubMed: 36523906
DOI: 10.1055/s-0042-1756286 -
Stress (Amsterdam, Netherlands) Jan 2019Stress is an important and modifiable determinant of health, and its association with hair cortisol concentrations (HCC) during pregnancy remains unclear. We selected a...
Stress is an important and modifiable determinant of health, and its association with hair cortisol concentrations (HCC) during pregnancy remains unclear. We selected a random sample of 97 participants from a cohort of pregnant participants attending prenatal clinics in Lima, Peru. Each provided a hair sample at enrollment (mean gestational age = 13.1 weeks) and again at full-term delivery. Hair samples were segmented to reflect HCC in preconception and each trimester. At enrollment, measures of stress included: difficulty accessing basic goods, educational attainment, exposure to violence, fair or poor general health, perceived stress, and symptoms of depression, general anxiety, and post-traumatic stress disorder. Linear mixed models evaluated the association between each stress measure and absolute and relative changes in HCC. Pearson correlation coefficients (r) assessed correlations between HCC and continuous stress scores. Educational attainment of ≤12 years was associated with higher HCC in preconception and the 1st trimester, and general anxiety with lower preconception HCC. When modeling HCC patterns across the 4 hair segments, an educational attainment of ≤12 years was associated with higher HCC, high perceived stress with lower HCC, and general anxiety with steeper increases in HCC (group by time p value = .02). Only preconception HCC and GAD scores correlated (r = -0.22, p = .04). We observed few associations between stress and HCC. However, those that were seen were generally restricted to the preconception and 1st trimester. Further investigations into the association between stress and changes in HCC across pregnancy are warranted, and should include the preconception where possible.
Topics: Adult; Anxiety; Cohort Studies; Depression; Depressive Disorder; Female; Gestational Age; Hair; Humans; Hydrocortisone; Liver Neoplasms; Male; Pregnancy; Stress, Psychological
PubMed: 30585520
DOI: 10.1080/10253890.2018.1504917 -
European Journal of Pharmacology Jun 2011The melanocortin MC(1) receptor is a G-protein coupled receptor expressed in the melanocytes of the skin and hair and is known for its key role in the regulation of... (Review)
Review
The melanocortin MC(1) receptor is a G-protein coupled receptor expressed in the melanocytes of the skin and hair and is known for its key role in the regulation of human pigmentation. Melanocortin MC(1) receptor activation after ultraviolet radiation exposure results in a switch from the red/yellow pheomelanin to the brown/black eumelanin pigment synthesis within cutaneous melanocytes; this pigment is then transferred to the surrounding keratinocytes of the skin. The increase in melanin maturation and uptake results in tanning of the skin, providing a physical protection of skin cells from ultraviolet radiation induced DNA damage. Melanocortin MC(1) receptor polymorphism is widespread within the Caucasian population and some variant alleles are associated with red hair colour, fair skin, poor tanning and increased risk of skin cancer. Here we will discuss the use of mouse coat colour models, human genetic association studies, and in vitro cell culture studies to determine the complex functions of the melanocortin MC(1) receptor and the molecular mechanisms underlying the association between melanocortin MC(1) receptor variant alleles and the red hair colour phenotype. Recent research indicates that melanocortin MC(1) receptor has many non-pigmentary functions, and that the increased risk of skin cancer conferred by melanocortin MC(1) receptor variant alleles is to some extent independent of pigmentation phenotypes. The use of new transgenic mouse models, the study of novel melanocortin MC(1) receptor response genes and the use of more advanced human skin models such as 3D skin reconstruction may provide key elements in understanding the pharmacogenetics of human melanocortin MC(1) receptor polymorphism.
Topics: Animals; Cell Line; Genotype; Humans; Melanocytes; Melanoma; Phenotype; Pigmentation; Receptor, Melanocortin, Type 1
PubMed: 21199646
DOI: 10.1016/j.ejphar.2010.11.040 -
The Journal of Investigative... Aug 1997Cutaneous pigmentation is a major determinant of the cutaneous response to ultraviolet radiation, and consequently of the risk of developing skin cancer. Over the past... (Review)
Review
Cutaneous pigmentation is a major determinant of the cutaneous response to ultraviolet radiation, and consequently of the risk of developing skin cancer. Over the past 10 years, several genes involved in melanogenesis have been identified, including the melanocortin 1 receptor gene. Recent work on the melanocortin 1 receptor suggests that it is a key player in determining whether eumelanin or pheomelanin is predominantly produced both in vitro and in vivo. In the mouse, variants of this receptor, which differ in their ability to activate adenylyl cyclase, are associated with different coat colors. In humans, melanocortin 1 receptor variants are associated with red hair and fair skin, and work in progress from our laboratory suggests that certain melanocortin 1 receptor variants may preferentially be associated with hair color rather than skin type. In addition, melanocortin 1 receptor variants are a risk factor, possibly independent of skin type, for melanoma susceptibility.
Topics: Animals; Cloning, Molecular; Hair Color; Humans; Melanoma; Phenotype; Receptors, Corticotropin; Receptors, Melanocortin; Risk Factors; Skin Neoplasms; Skin Pigmentation
PubMed: 9487023
DOI: 10.1038/jidsymp.1997.18 -
International Journal of Trichology 2018Hair is said to gray prematurely when a minimum of five gray hairs occurs before the age of 20 in fair skinned, 25 in Asians, and 30 in Africans. It may be genetically...
CONTEXT
Hair is said to gray prematurely when a minimum of five gray hairs occurs before the age of 20 in fair skinned, 25 in Asians, and 30 in Africans. It may be genetically associated with autoimmune syndromes or certain environmental factors.
AIMS
The aim of this study was to evaluate the serum level of iron, copper, and calcium and to assess their role in premature hair graying.
SUBJECTS AND METHODS
This study was carried out on 60 patients with premature hair graying (PHG) and 30 age- and sex-matched healthy individuals served as a control group. The severity of PHG was assessed by the hair whitening scoring system. Serum iron, copper, and calcium concentrations were measured using Beckman Coulter instrument and spectrophotometric method.
RESULTS
There was a reduction in serum levels of iron, copper, and calcium in patients with PHG in comparison with controls. There was a statistically negative significant correlation between the severity of PHG and serum iron and calcium levels. There was a negative nonsignificant correlation between body mass index and serum iron, copper, and calcium levels.
CONCLUSIONS
Serum iron, copper, and calcium levels were reduced in association with PHG and correlated with its severity. Premature graying may be an indicator that hair is not getting enough nutrients and minerals, and supplementation with these trace elements might reverse and is expected to prevent progression of canities; however, further studies are needed to find the underlying mechanism of this relationship.
PubMed: 30783336
DOI: 10.4103/ijt.ijt_8_18 -
Bulletin of the World Health... 1987Ultra-violet radiation (UVR) in sunlight is thought to be the main cause of malignant melanoma in lightly-pigmented populations. Individuals with fair skin, fair hair,... (Review)
Review
Ultra-violet radiation (UVR) in sunlight is thought to be the main cause of malignant melanoma in lightly-pigmented populations. Individuals with fair skin, fair hair, blue eyes and/or a tendency to burn rather than tan when exposed to the sun are at particularly high risk of melanoma and should be given special attention in primary prevention programmes. Intermittent exposure to the sun, as in recreational exposure, may be a more potent cause of melanoma than more continuous exposure. Primary prevention offers the best prospects for a substantial reduction in mortality from malignant melanoma. However, there is little evidence available to judge the effectiveness of primary prevention of melanoma through reduction of exposure to the sun. Education for reducing exposure to the sun is common in high-risk populations but has never been evaluated adequately. Mortality from melanoma could also possibly be reduced by earlier diagnosis through education or screening of high-risk groups. Regular screening of patients with the familial dysplastic naevus syndrome should reduce their mortality from melanoma.
Topics: Humans; Melanoma; Skin Neoplasms
PubMed: 3301043
DOI: No ID Found