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Drug Design, Development and Therapy 2019Minoxidil was first introduced as an antihypertensive medication and the discovery of its common adverse event, hypertrichosis, led to the development of a topical... (Review)
Review
Minoxidil was first introduced as an antihypertensive medication and the discovery of its common adverse event, hypertrichosis, led to the development of a topical formulation for promoting hair growth. To date, topical minoxidil is the mainstay treatment for androgenetic alopecia and is used as an off-label treatment for other hair loss conditions. Despite its widespread application, the exact mechanism of action of minoxidil is still not fully understood. In this article, we aim to review and update current information on the pharmacology, mechanism of action, clinical efficacy, and adverse events of topical minoxidil.
Topics: Animals; Antihypertensive Agents; Hair; Humans; Hypertrichosis; Minoxidil; Molecular Structure; Sulfotransferases
PubMed: 31496654
DOI: 10.2147/DDDT.S214907 -
Current Biology : CB Feb 2009Hair is a primary characteristic of mammals, and exerts a wide range of functions including thermoregulation, physical protection, sensory activity, and social... (Review)
Review
Hair is a primary characteristic of mammals, and exerts a wide range of functions including thermoregulation, physical protection, sensory activity, and social interactions. The hair shaft consists of terminally differentiated keratinocytes that are produced by the hair follicle. Hair follicle development takes place during fetal skin development and relies on tightly regulated ectodermal-mesodermal interactions. After birth, mature and actively growing hair follicles eventually become anchored in the subcutis, and periodically regenerate by spontaneously undergoing repetitive cycles of growth (anagen), apoptosis-driven regression (catagen), and relative quiescence (telogen). Our molecular understanding of hair follicle biology relies heavily on mouse mutants with abnormalities in hair structure, growth, and/or pigmentation. These mice have allowed novel insights into important general molecular and cellular processes beyond skin and hair biology, ranging from organ induction, morphogenesis and regeneration, to pigment and stem cell biology, cell proliferation, migration and apoptosis. In this review, we present basic concepts of hair follicle biology and summarize important recent advances in the field.
Topics: Animals; Hair Diseases; Hair Follicle; Mice; Morphogenesis; Stem Cells
PubMed: 19211055
DOI: 10.1016/j.cub.2008.12.005 -
The Journal of Investigative... Dec 2007Shiny hair with a smooth texture and clean-cut ends or tapered tips is generally perceived to be healthy. Hair texture and shine relate to hair surface properties,... (Review)
Review
Shiny hair with a smooth texture and clean-cut ends or tapered tips is generally perceived to be healthy. Hair texture and shine relate to hair surface properties, whereas the integrity of hair ends relates to the hair cortex. Hair can be straight, wavy or curly, blonde, black, brown, red, gray white, and its natural variations are important to our identity. Manipulation of the normal structure of the hair shaft is epidemic and dictated by culture, fashion, and above all, celebrity. Although cosmetic procedures are intrinsically safe, there is potential for damage to the hair. Loss of lustre, frizz, split ends, and other hair problems are particularly prevalent among people who repeatedly alter the natural style of their hair or among people with hair that is intrinsically weak. This may be due to individual or racial variation or less commonly an inherited structural abnormality in hair fiber formation. Hair health is also affected by common afflictions of the scalp as well as age-related phenomena such as graying and androgenetic alopecia. Hair products that improve the structural integrity of hair fibers and increase tensile strength are available, as are products that increase hair volume, reduce frizz, improve hair manageability, and stimulate new hair growth.
Topics: Eicosanoic Acids; Female; Hair; Hair Diseases; Hair Preparations; Humans; Hygiene
PubMed: 18004288
DOI: 10.1038/sj.jidsymp.5650046 -
Cell Stem Cell Jan 2022In aging, androgenic alopecia, and genetic hypotrichosis disorders, hair shaft miniaturization is often associated with hair follicle stem cell (HFSC) loss. However, the...
In aging, androgenic alopecia, and genetic hypotrichosis disorders, hair shaft miniaturization is often associated with hair follicle stem cell (HFSC) loss. However, the mechanism causing this stem cell depletion in vivo remains elusive. Here we show that hair shaft loss or a reduction in diameter shrinks the physical niche size, which results in mechanical compression of HFSCs and their apoptotic loss. Mechanistically, cell compression activates the mechanosensitive channel Piezo1, which triggers calcium influx. This confers tumor necrosis factor alpha (TNF-α) sensitivity in a hair-cycle-dependent manner in otherwise resistant HFSCs and induces ectopic apoptosis. Persistent hair shaft miniaturization during aging and genetic hypotrichosis disorders causes long-term HFSC loss by inducing continuous ectopic apoptosis through Piezo1. Our results identify an unconventional role of the inert hair shaft structure as a functional niche component governing HFSC survival and reveal a mechanosensory axis that regulates physical-niche-atrophy-induced stem cell depletion in vivo.
Topics: Calcium; Hair Follicle; Miniaturization; Stem Cells; Tumor Necrosis Factor-alpha
PubMed: 34624205
DOI: 10.1016/j.stem.2021.09.009 -
Science Advances Oct 2022During embryonic development, reciprocal interactions between epidermal and mesenchymal layers trigger hair follicle morphogenesis. This study revealed that...
During embryonic development, reciprocal interactions between epidermal and mesenchymal layers trigger hair follicle morphogenesis. This study revealed that microenvironmental reprogramming via control over these interactions enabled hair follicle induction in vitro. A key approach is to modulate spatial distributions of epithelial and mesenchymal cells in their spontaneous organization. The de novo hair follicles with typical morphological features emerged in aggregates of the two cell types, termed hair follicloids, and hair shafts sprouted with near 100% efficiency in vitro. The hair shaft length reached ~3 mm in culture. Typical trichogenic signaling pathways were up-regulated in hair follicloids. Owing to replication of hair follicle morphogenesis in vitro, melanosome production and transportation were also monitored in the hair bulb region. This in vitro hair follicle model might be valuable for better understanding hair follicle induction, evaluating hair growth and inhibition of hair growth by drugs, and modeling gray hairs in a well-defined environment.
PubMed: 36269827
DOI: 10.1126/sciadv.add4603 -
Biomolecules Apr 2023Plant-derived secondary metabolites (polyphenols/terpenes/alkaloids) and microbial exometabolites/membrane components of fermented tropical fruits are known as highly... (Randomized Controlled Trial)
Randomized Controlled Trial
Plant-derived secondary metabolites (polyphenols/terpenes/alkaloids) and microbial exometabolites/membrane components of fermented tropical fruits are known as highly bioavailable biomolecules causing skin and hair improvement effects (wound healing, anti-inflammatory, antioxidant, antidiabetic, antiacne, skin/hair microbiota balancing, hair growth-promoting, and hair loss-inhibiting). Caffein is considered as a hair growth promoter. A randomized placebo- and caffein-controlled clinical trial on the efficacy of fermented papaya (FP) plus fermented mangosteen (FM) towards human hair quality and loss was conducted. Shampoo and lotion hair care products containing FP, FM, and caffein as active agents were developed and applied to 154 subjects of both sexes with clinically confirmed androgenic or diffuse alopecia for 3 months. Their clinical efficacy was assessed subjectively by questionnaires filled in by dermatologists/trichologists, and by the objective trichomicroscopical calculations. Hair and scalp skin quality was determined by microbiota pattern and ATP, SH-groups, protein, and malonyl dialdehyde quantification. Comparative clinical data showed that the experimental hair care cosmetics significantly inhibited hair loss, increased hair density/thickness, and improved hair follicle structure versus placebo and caffein controls. The cosmetics with FP and FM substantially normalized the microbiota pattern and increased ATP content in hair follicle, while inhibiting lipid peroxidation in the scalp skin, and SH-group formation in the hair shaft.
Topics: Female; Humans; Male; Adenosine Triphosphate; Fruit; Hair; Microbiota; Scalp; Alopecia; Fermentation
PubMed: 37189446
DOI: 10.3390/biom13040699 -
ELife Jun 2021Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
BACKGROUND
Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
METHODS
Here, we develop an approach to profile hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions.
RESULTS
Using this method, we show white/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, thereby quantitatively defining the reversibility of greying in humans. Molecularly, grey hairs upregulate proteins related to energy metabolism, mitochondria, and antioxidant defenses. Combining HPP profiling and proteomics on single hairs, we also report hair greying and reversal that can occur in parallel with psychological stressors. To generalize these observations, we develop a computational simulation, which suggests a threshold-based mechanism for the temporary reversibility of greying.
CONCLUSIONS
Overall, this new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology.
FUNDING
This work was supported by the Wharton Fund and NIH grants GM119793, MH119336, and AG066828 (MP).
Topics: Adolescent; Adult; Aging; Child; Chromosome Mapping; Hair; Hair Color; Humans; Middle Aged; Stress, Psychological; Young Adult
PubMed: 34155974
DOI: 10.7554/eLife.67437 -
Theranostics 2020It is estimated that 50% of men and 25% of women worldwide suffer from hair loss, and therefore it is of great significance to investigate the molecular pathways driving...
It is estimated that 50% of men and 25% of women worldwide suffer from hair loss, and therefore it is of great significance to investigate the molecular pathways driving hair follicle de novo morphogenesis. However, due to high cellular heterogeneity and the asynchronous development of hair follicles, our current understanding of the molecular mechanisms involved in follicle development remains limited. Single-cell suspensions from the dorsal skin of E13.5 (induction stage), E16.5 (organogenesis) fetal mice, and newborn mice (cytodifferentiation stage, postnatal day 0, P0) were prepared for unbiased single-cell RNA sequencing. To delineate the single-cell transcriptional landscape during hair follicle de novo morphogenesis, we performed t-distributed Stochastic Neighbor Embedding (tSNE), pseudotime cell trajectory inference, and regulon enrichment analysis to dissect cellular heterogeneity and reveal the molecular pathways underlying major cell type cell fate decisions. To validate our analysis, we further performed immunohistochemistry analysis of the key molecules involved during hair follicle morphogenesis. Meanwhile, intercellular communication between different cell populations was inferred based on a priori knowledge of ligand-receptor pairs. Based on tSNE analysis, we identified 14 cell clusters from skin tissue and delineated their cellular identity from specific gene expression profiles. By using pseudotime ordering analysis, we successfully constructed the epithelium/dermal cell lineage differentiation trajectory. For dermal cell lineage, our analysis here recapitulated the dynamic gene expression profiles during dermal condensate (DC) cell fate commitment and delineated the heterogeneity of the different dermal papilla (DP) cell populations during in utero hair follicle development. For the epithelium cell lineage, our analysis revealed the dynamic gene expression profiles of the underappreciated matrix, interfollicular epidermis (IFE), hair shaft and inner root sheath (IRS) cell populations. Furthermore, single-cell regulatory network inference and clustering analysis revealed key regulons during cell fate decisions. Finally, intercellular communication analysis demonstrated that strong intercellular communication was involved during early hair follicle development. Our findings here provide a molecular landscape during hair follicle epithelium/dermal cell lineage fate decisions, and recapitulate the sequential activation of core regulatory transcriptional factors (TFs) in different cell populations during hair follicle morphogenesis. More importantly, our study here represents a valuable resource for understanding the molecular pathways involved during hair follicle de novo morphogenesis, which will have implications for future hair loss treatments.
Topics: Animals; Animals, Newborn; Cell Communication; Cell Differentiation; Cell Lineage; Embryo, Mammalian; Female; Hair Follicle; Male; Mice; Models, Animal; Organogenesis; RNA-Seq; Signal Transduction; Single-Cell Analysis; Skin
PubMed: 32685006
DOI: 10.7150/thno.44306