Diabetes mellitus is one of the most prevalent diseases in modern society. Many complicationssuch as hepatic cirrhosis, neuropathy, cardiac infarction, and so on are associated with diabetes. ...Although a relationship between diabetes and hair loss has been recently reported, the treatment of diabetic hair loss by Wnt/β-catenin activators has not been achieved yet. In this study, we found that the depilation-induced anagen phase was delayed in both db/db mice and high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. In diabetic mice, both hair regrowth and wound-induced hair follicle neogenesis (WIHN) were reduced because of suppression of Wnt/β-catenin signaling and decreased proliferation of hair follicle cells. We identified that KY19382, a small molecule that activates Wnt/β-catenin signaling, restored the capabilities of regrowth and WIHN in diabetic mice. The Wnt/β-catenin signaling activator also increased the length of the human hair follicle which was decreased under high glucose culture conditions. Overall, the diabetic condition reduced both hair regrowth and regeneration with suppression of the Wnt/β-catenin signaling pathway. Consequently, the usage of Wnt/β-catenin signaling activators could be a potential strategy to treat diabetes-induced alopecia patients. BMB Reports 2022; 55(11): 559-564.
Investigations on carrier‐based drug delivery systems for higher selectivity in hair therapy have clearly evolved from dye release and model studies to highly sophisticated approaches, many of which ...specifically tackle hair indications and the delivery of hair‐relevant molecules. Here, we group recent hair disease‐oriented work into efforts towards (i) improved delivery of conventional drugs, (ii) delivery of novel drug classes, for example biomolecules and (iii) targeted delivery on the cellular/molecular level. Considering the solid foundation of experimental work, it does not take a large step outside the current box of thinking to follow the idea of using large carriers (>500 nm, unlikely to penetrate as a whole) for follicular penetration, retention and protection of sensitive compounds. Yet, reports on particles <200 nm being internalized by keratinocytes and dendritic cells at sites of barrier disruption (e.g., hair follicles) combined with recent advances in nanodermatology add interesting new facets to the possibilities carrier technologies could offer, for example, unprecedented levels of selectivity. The authors provide thought‐provoking ideas on how smart delivery technologies and advances in our molecular understanding of hair pathophysiology could result in a whole new era of hair therapeutics. As the field still largely remains in preclinical investigation, determined efforts towards production of medical grade material and truly translational work are needed to demonstrate surplus value of carrier systems for clinical applications.
Notch genes encode evolutionarily conserved large, single transmembrane receptors, which regulate many cell fate decisions and differentiation processes during fetal and postnatal life. Multiple ...Notch receptors and ligands are expressed in both developing and adult epidermis and hair follicles. Proliferation and differentiation of these two ectodermal-derived structures have been proposed to be controlled in part by the Notch pathway. Whether Notch signaling is involved in postnatal hair homeostasis is currently unknown. Here, we investigate and compare the role of the Notch1 receptor during embryonic hair follicle development and postnatal hair homeostasis using Cre-loxP based tissue specific and inducible loss-of-function approaches. During embryonic development, tissue-specific ablation of Notch1 does not perturb formation and patterning of hair follicle placodes. However, Notch1 deficient hair follicles invaginate prematurely into the dermis. Embryonic as well as postnatal inactivation of Notch1 shortly after birth or in adult mice results in almost complete hair loss followed by cyst formation. The first hair cycle of Notch1 deficient mice is characterized by shortened anagen and a premature entry into catagen. These data show that Notch1 is essential for late stages of hair follicle development during embryogenesis as well as for post-natal hair follicle development and hair homeostasis.
Summary
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.
The study demonstrated that melatonin (MT) can induce the development of secondary hair follicles in Inner Mongolian cashmere goats through the Wnt10b gene, leading to secondary dehairing. However, ...the mechanisms underlying the expression and molecular function of Wnt10b in dermal papilla cells (DPC) remain unknown. This research aimed to investigate the impact of MT on DPC and the regulation of Wnt10b expression, function, and molecular mechanisms in DPC. The findings revealed that MT promotes DPC proliferation and enhances DPC activity. Co-culturing DPC with overexpressed Wnt10b and MT showed a significant growth promotion. Subsequent RNA sequencing (RNA-seq) of overexpressed Wnt10b and control groups unveiled the regulatory role of Wnt10b in DPC. Numerous genes and pathways, including developmental pathways such as Wnt and MAPK, as well as processes like hair follicle morphogenesis and hair cycle, were identified. These results suggest that Wnt10b promotes the growth of secondary hair follicles in Inner Mongolian cashmere goats by regulating crucial factors and pathways in DPC proliferation.
•Melatonin promotes goat hair papilla cell proliferation, with the highest value-added efficiency at 300 pg/mL, and affects Wnt pathway-related gene expression.•The successful construction of Wnt10b overexpression and interference vectors and transfection into velvet goat hair papilla cells.•Detection of the effect of Wnt10b on DPCs using RNA-seq technique.
Highlights • Hair glucocorticoids (cortisol and cortisone) are increasingly used to evaluate long-term HPA axis activity in relation to somatic and psychological health, but are subject to ...‘wash-out’: the gradual decrease of glucocorticoid content along the hair shaft. • We hypothesized that wash-out of hair glucocorticoids may in part be caused by ultraviolet (UV) radiation present in natural sunlight. • In our experiments, hair cortisol and cortisone were decreased after exposure to a high amount of artificial UV radiation, but also after 40 h of natural sunlight exposure. • Sunlight exposure should be considered as a potential confounder in studies investigating hair glucocorticoids.
Background
Hair dye is a concoction of various ingredients that can result in allergic contact dermatitis (ACD) which is a common problem encountered by dermatologists.
Objectives
To find out the ...presence of potent contact sensitizers in commercially available hair dyes in Puducherry, a union territory in South India, and to compare the findings with similar studies conducted in different countries.
Methods
Ingredients labels of 159 hair dye products from 30 brands that were manufactured and marketed in India screened for the presence of contact sensitizers.
Results
A total of 25 potent contact sensitizers were found in 159 hair dye products. p‐Phenylenediamine and resorcinol were the most frequent contact sensitizer found in the study. The mean contact sensitizer concentration in a single hair dye product is 3.72 ± 1.81. The number of potent contact sensitizers in individual hair dye products ranged from 1 to 10.
Conclusion
We observed that most of the consumer‐available hair dyes contain multiple contact sensitizers. Also, an inadequacy in mentioning the p‐Phenylenediamine content, and appropriate warning contents regarding hair dye use were not mentioned in the cartons.
This study identifies the potent contact sensitizers in commercially available hair dyes in South India.
Spontaneous bursts of electrical activity in the developing auditory system arise within the cochlea before hearing onset and propagate through future sound-processing circuits of the brain to ...promote maturation of auditory neurons. Studies in isolated cochleae revealed that this intrinsically generated activity is initiated by ATP release from inner supporting cells (ISCs), resulting in activation of purinergic autoreceptors, K
efflux, and subsequent depolarization of inner hair cells. However, it is unknown when this activity emerges or whether different mechanisms induce activity during distinct stages of development. Here we show that spontaneous electrical activity in mouse cochlea from both sexes emerges within ISCs during the late embryonic period, preceding the onset of spontaneous correlated activity in inner hair cells and spiral ganglion neurons, which begins at birth and follows a base to apex developmental gradient. At all developmental ages, pharmacological inhibition of P2Y1 purinergic receptors dramatically reduced spontaneous activity in these three cell types. Moreover,
imaging within the inferior colliculus revealed that auditory neurons within future isofrequency zones exhibit coordinated neural activity at birth. The frequency of these discrete bursts increased progressively during the postnatal prehearing period yet remained dependent on P2RY1. Analysis of mice with disrupted cholinergic signaling in the cochlea indicate that this efferent input modulates, rather than initiates, spontaneous activity before hearing onset. Thus, the auditory system uses a consistent mechanism involving ATP release from ISCs and activation of P2RY1 autoreceptors to elicit coordinated excitation of neurons that will process similar frequencies of sound.
In developing sensory systems, groups of neurons that will process information from similar sensory space exhibit highly correlated electrical activity that is critical for proper maturation and circuit refinement. Defining the period when this activity is present, the mechanisms responsible and the features of this activity are crucial for understanding how spontaneous activity influences circuit development. We show that, from birth to hearing onset, the auditory system relies on a consistent mechanism to elicit correlate firing of neurons that will process similar frequencies of sound. Targeted disruption of this activity will increase our understanding of how these early circuits mature and may provide insight into processes responsible for developmental disorders of the auditory system.
Background
The burden of occupational hand eczema in hairdressers is high, and (partly strong) allergens abound in the hair cosmetic products they use.
Objectives
To systematically review published ...evidence concerning contact allergy to an indicative list of active ingredients of hair cosmetics, namely, p‐phenylenediamine (PPD), toluene‐2,5‐diamine (PTD), persulfates, mostly ammonium persulfate (APS), glyceryl thioglycolate (GMTG), and ammonium thioglycolate (ATG), concerning the prevalence of sensitization, particularly in terms of a comparison (relative risk; RR) between hairdressers and non‐hairdressers.
Methods
Following a PROSPERO‐registered and published protocol, eligible literature published from 2000 to February 2021 was identified, yielding 322 publications, and extracted in standardized publication record forms, also considering risk of bias.
Results
Based on 141 publications, the contact allergy prevalence to PPD was 4.3% (95% CI: 3.8–4.9%) in consecutively patch tested patients. Other ingredients were mostly tested in an aimed fashion, yielding variable, and partly high contact allergy prevalences. Where possible, the RR was calculated, yielding an average increased sensitization risk in hairdressers of between 5.4 (PPD) and 3.4 (ATG). Additional evidence related to immediate‐type hypersensitivity, experimental results, exposures, and information from case reports was qualitatively synthesized.
Conclusions
An excess risk of contact allergy is clearly evident from the pooled published evidence from the last 20 years. This should prompt an improvement in working conditions and product safety.
Relative Risk (RR) of contact allergy to the hair cosmetic ingredients listed in patch tested hairdressers compared to other patch tested patients (“controls”).
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