Promote Hair Growth Research Articles

013 IL-15/IL-15Rα signaling is a guardian of human hair follicle immune privilege and promotes hair growth

Though these drugs tend to be effective alopecia areata (AA) therapeutics, AA quickly relapses after discontinuing treatment with JAK1/3 inhibitors (JAKi). One reason could be that JAKi also block the signaling of AA-protective cytokines that signal via the common γ-chain, which is also used by interleukin-15 (IL-15). IL-15 is known to suppress mouse HF apoptosis, promote murine HF growth in vivo, and is required to maintain (AA-protective!) iNKT cells. Moreover, it is unclear how IL-15 affects human hair follicle (HF)-immune privilege (IP) and catagen development, namely via signaling through its private receptor, IL-15Rα.

The Molecular Mechanism of Natural Products Activating Wnt/β-Catenin Signaling Pathway for Improving Hair Loss.

Hair loss, or alopecia, is a dermatological disorder that causes psychological stress and poor quality of life. Drug-based therapeutics such as finasteride and minoxidil have been clinically used to treat hair loss, but they have limitations due to their several side effects in patients. To solve this problem, there has been meaningful progress in elucidating the molecular mechanisms of hair growth and finding novel targets to develop therapeutics to treat it. Among various signaling pathways, Wnt/β-catenin plays an essential role in hair follicle development, the hair cycle, and regeneration. Thus, much research has demonstrated that various natural products worldwide promote hair growth by stimulating Wnt/β-catenin signaling. This review discusses the functional role of the Wnt/β-catenin pathway and its related signaling molecules. We also review the molecular mechanism of the natural products or compounds that activate Wnt/β-catenin signaling and provide insights into developing therapeutics or cosmeceuticals that treat hair loss.

Efficacy of Asymmetric siRNA Targeting Androgen Receptors for the Treatment of Androgenetic Alopecia.

Asymmetric small interfering RNAs (asiRNAs) that mediate RNA interference have been investigated for therapeutic use in various tissues, including skin tissue. Androgenetic alopecia (AGA) is caused by a combination of genetic factors, resulting in sensitivity to dihydrotestosterone (DHT), which binds to the androgen receptor (AR) to mediate a series of biomolecular changes leading to hair loss. This study aimed to evaluate the therapeutic potential of a cell-penetrating, AR-targeting asiRNA (cp-asiAR) for AGA treatment, which was designed to silence the AR gene. AGA mouse models were developed by stimulation with DHT, and ex vivo human scalp tissues were also used for analysis. Cp-asiAR-mediated changes in mRNA expression and protein levels of AR were assessed along with the examination of phenotypic improvements in mouse model of AGA. We also assessed downstream signaling associated with AR in primary human dermal papilla (DP) cells. Several cp-asiARs were screened for selecting the optimal sequence of AR using cell lines in vitro. A cholesterol-conjugated, chemically modified cp-asiAR candidate was optimized under passive uptake conditions in vitro. Intradermal cp-asiAR injection efficiently reduced mRNA and protein levels corresponding to AR in mouse models. Moreover, cp-asiAR injection promoted hair growth in mouse models with DHT-induced AGA. In ex vivo human hair follicle culture, the proportion of telogen hair decreased, and the mean hair bulb diameter increased in the cp-asiAR-treated group. In isolated primary human DP cells, AR expression was effectively downregulated by cp-asiAR. Furthermore, cp-asiAR attenuated DHT-mediated increases in interleukin-6, transforming growth factor-β1, and dickkopf-1 levels. No significant toxicity was observed in DP cells after cp-asiAR treatment. Cp-asiAR treatment showed effective downregulation of AR expression and prevention of DHT-mediated alterations in the hair cycle and hair diameter, indicating its potential as a novel therapeutic option for AGA.

Antioxidant Capacity and Protective Effect of Cow Placenta Extract on D-Galactose-Induced Skin Aging in Mice.

Placental extract has been used for skin care and delaying skin aging. Cow placenta is an abundant resource with a large mass, which has not been harnessed effectively. Cow placenta extract (CPE) has the functions of antioxidation, anti-inflammatory, promoting growth and development, and promoting hair growth. However, little is known about the effect of oral administration of cow placenta extract on skin conditions. Therefore, the present study aimed to investigate the antioxidant capacity of CPE in vitro and in vivo and its protective effect on d-galactose (D-gal) induced skin aging in mice. The results showed that CPE had strong free radical scavenging, reducing and metal chelating activities. CPE can increase the activity of catalase (CAT), glutathione peroxidase (GSH-Px), peroxidase (POD), superoxide dismutase (SOD), and the content of glutathione (GSH), decrease the content of malondialdehyde (MDA). Moreover, CPE can decrease the gene and protein expression of matrix metalloproteinase 1a (MMP-1a) and matrix metalloproteinase 3 (MMP-3) and increase the expression of transforming growth factor-β (TGF-β) and tissue inhibitor of metalloproteinase 1 (TIMP-1) of mouse skin. Histopathological analysis showed CPE reduced the collagen damage caused by D-gal, increased collagen synthesis and reduced its degradation to delay skin aging.

Health Benefits and Safety of Red Pigmented Rice (Oryza sativa L.): In Vitro, Cellular, and In Vivo Activities for Hair Growth Promoting Treatment

The hair growth-promoting activities of Thai native red (Sang-Yod-SY and Mun-Poo-MP) and black (Black glutinous-BG and Hom-Nil-HN) pigmented rice (Oryza sativa L.) extracts, including in vitro 5α-reductase inhibition, hair growth-promoting activity on human hair germinal matrix cells, and in vivo hair-cycle-converting activity in C3H/HeMlac mice, were investigated. Moreover, these extracts were determined to be safe via cytotoxicity (HaCaT cell) and in vivo irritation tests. The results showed that SY red rice extract with high contents of proanthocyanidin (1.50 ± 0.16 mgECE/g extract) exhibited significantly higher 5α-reductase inhibitory activity (18.5 ± 9.0 mgFEA/g extract) (p < 0.05). The maximum growth-promoting activity for human matrix cells treated with SY extract reached about 216.2 ± 0.7% (1 mg/mL) relative to control (100%) after 3 days culture (p < 0.05). Moreover, topical application of 1 mg/mL SY red pericarp rice extracts on shaven C3H skin in telogen phase led to significant hair regeneration (97.2 ±1.3%) based on the shaven area, while vehicle application only tended to yield a regeneration of 50.9 ± 11.7%. Red rice extracts were found to be safe, without signs of cytotoxicity and irritation. This research demonstrates the health benefits and safety of SY red pericarp extract when used for hair growing activity and its potential for use as a natural hair growth promoter and 5α-reductase inhibitor.

Cucurbitacin promotes hair growth in mice by inhibiting the expression of fibroblast growth factor 18.

The inhibition of fibroblast growth factor 18 (FGF18) promotes the transition of hair follicles (HFs) from the telogen phase to the anagen phase. Cucurbitacin has been shown to have a good effect in promoting hair cell growth. This study explored the potential effect of cucurbitacin on hair growth and its effect on FGF18 expression in mice. Male C57BL/6J mice were randomly divided into the following two groups: (I) the vehicle group; and (II) the cucurbitacin group. Matrix cream and cucurbitacin cream were applied to the depilated skin on the back of the vehicle group mice and the cucurbitacin group mice, respectively. On days 3, 6, 9, 12, 15, and 18, the hair growth in the depilated dorsal skin of the mice was recorded with a digital camera and a HF detector, and the HF cycle status of the mice was observed by hematoxylin and eosin (H&E) staining. In addition, the level of FGF18 messenger ribonucleic acid (mRNA) in the dorsal skin was measured on days 15 and 18 by quantitative real-time polymerase chain reaction (qRT-PCR), while the level of FGF18 protein was measured by western blot and immunofluorescence staining. The dorsal skin to which the cucurbitacin cream was applied began to darken on day 6 and grew hairs on day 9, which was 3 days earlier than the dorsal skin to which the matrix cream was applied. The H&E staining revealed a transition from the telogen phase to the anagen phase 3 days earlier for the cucurbitacin cream-treated skin than the matrix cream-treated skin. In addition, the skin treated with cucurbitacin cream also showed a significant decrease in FGF18 mRNA as seen by qRT-PCR, and reduced FGF18 protein levels as detected by western blot and immunofluorescence staining compared to the skin treated with matrix cream only. Cucurbitacin significantly reduced the levels of FGF18 mRNA and protein in the dorsal skin of mice to accelerate the HFs to enter the anagen phase earlier, thereby promoting the regeneration of hair. Thus, cucurbitacin can be considered a new and valuable agent for the development of anti-hair loss products.

Vitamins and their derivatives synergistically promote hair shaft elongation ex vivo via PlGF/VEGFR-1 signalling activation

BackgroundAlthough vitamins or their derivatives (Vits), such as panthenyl ethyl ether, tocopherol acetate, and pyridoxine, have been widely used in topical hair care products, their efficacy and mode of action have been insufficiently studied. ObjectiveTo elucidate the biological influence of Vits on hair follicles and determine the underlying mechanisms. MethodsA mouse vibrissa hair follicle organ culture model was utilized to evaluate the effects of Vits on hair shaft elongation. Gene and protein expression analyses and histological investigations were conducted to elucidate the responsible mechanisms. A human hair follicle cell culture was used to assess the clinical relevance. ResultsIn organ culture models, the combination of panthenyl ethyl ether, tocopherol acetate, and pyridoxine (namely, PPT) supplementation significantly promoted hair shaft elongation. PPT treatment enhanced hair matrix cell proliferation by 1.9-fold compared to controls, as demonstrated by Ki67-positive immunoreactivity. PPT-treated mouse dermal papillae exhibited upregulated Placental growth factor (Plgf) by 1.6-fold compared to controls. Importantly, the addition of PlGF neutralizing antibodies to the ex vivo culture diminished the promotive effect on hair growth and increase in VEGFR-1 phosphorylation achieved by PPT. A VEGFR-1 inhibitor also inhibited the promotion of hair growth. Microarray analysis suggested synergistic summation of individual Vits’ bioactivity, putatively explaining the effect of PPT. Moreover, PPT increased PlGF secretion in cultured human dermal papilla cells. ConclusionOur findings suggested that PPT promoted hair shaft elongation by activating PlGF/VEGFR-1 signalling. The current study can shed light on the previously underrepresented advantage of utilizing Vits in hair care products.

Hair Growth Promotion of Argan Oil (Argania Spinosa Skeels) Nanoemulsion Hair Tonic Preparation With Mice (Mus Musculus)

Argan oil is not only used in facial treatments but can also be used for hair care. Argan oil has hair growth activity as it contains oleic acid and linoleic acid, which act to prevent hair loss, strengthen hair, and protect against harmful hair cosmetics, as well as containing tocopherol, which has antioxidant properties. Tocopherol can help to protect from the effects of UV radiation which can damage hair through the melanin pigment and protein fraction. This study aimed to determine the effect of variations in the concentration of argan oil (Argania spinosa Skeels) with levels of 1%, 2%, 3%, in hair tonic nanoemulsion preparations on the hair growth of mice. Hair growth activity was carried out using mice for 21 days. The data were analyzed using one way ANOVA and paired-sample t test. The results showed that after 21 days of testing, there was an increase in hair growth from each formula and the positive control, of 1.891 mm, 2.33mm, 3.484 mm and 2.225 mm, respectively. The hair weights of formula 1, 2, 3, and the positive control were 0.0028, 0.0059, 0.0111 and 0.0070, respectively. The negative control led to a decrease in length and weight by 0.641 mm and -0.0023, respectively. In conclusion, the preparations of hair tonic nanoemulsion using argan oil at concentrations of 1%, 2%, and 3% promoted hair growth in mice.
 Keywords: argan oil, hair tonic, nanoemulsion, hair growth activity test, mice

Effects of taxifolin from enzymatic hydrolysis of Rhododendron mucrotulatum on hair growth promotion.

Flavonoid aglycones possess biological activities, such as antioxidant and antidiabetic activities compared to glycosides. Taxifolin, a flavonoid aglycones, is detected only in trace amounts in nature and is not easily observed. Therefore, in this study, to investigate the hair tonic and hair loss inhibitors effect of taxifolin, high content of taxifolin aglycone extract was prepared by enzymatic hydrolysis. Taxifolin effectively regulates the apoptosis of dermal papilla cells, which is associated with hair loss, based on its strong antioxidant activities. However, inhibition of dihydrotestosterone (DHT), which is a major cause of male pattern hair loss, was significantly reduced with taxifolin treatment compared with minoxidil, as a positive control. It was also confirmed that a representative factor for promoting hair growth, IGF-1, was significantly increased, and that TGF-β1, a representative biomarker for hair loss, was significantly reduced with taxifolin treatment. These results suggest that taxifolin from enzymatic hydrolysis of RM is a potential treatment for hair loss and a hair growth enhancer.

33451 Social media hair and scalp oil trends

Background: Social media provides a unique paradox: it allows for widespread dispersion of general medical care recommendations but also the potential for misinformation. Skin and hair tips make up a large amount of social media posts and are sometimes posted by participants without any credentials. This can result in “hair trends” that gain popularity, but may not be backed by science. One such trend is the use of oils on the hair and scalp for the purpose of hair growth. Herein, we review the scientific evidence for oils and the promotion of hair growth.

In Vitro Biological Activity and In Vivo Human Study of Porcine-Placenta-Extract-Loaded Nanovesicle Formulations for Skin and Hair Rejuvenation.

Porcine placenta extract (PPE) contains many water-soluble macromolecular compounds, such as proteins and growth factors, which have limited transportation through the skin. This study aimed to assess the effect of porcine-placenta-extract (PPE)-loaded nano-transdermal systems for skin repair and hair growth promotion. The potentials of the nanoformulation for cytotoxicity, cell proliferation, intracellular reactive oxygen species (ROS) reduction, lipoxygenase inhibition, intracellular inflammatory cytokine reduction, and cell aggregation were evaluated. PPE-entrapped niosome nanovesicles were produced by thin-film hydration and probe-sonication methods, followed by incorporation in a skin serum formulation. The physicochemical properties of the formulation were examined, and the efficacy of the serum formulation was elucidated in humans. The results showed that PPE had no toxicity and was able to induce cell growth and cell aggregation. In addition, PPE significantly decreased intracellular ROS, inhibited lipoxygenase activity, and reduced the production of intracellular tumor necrosis factor-α. In the in vivo human study, the PPE nanovesicles-loaded serum could improve skin properties by increasing skin hydration. Moreover, it was capable of promoting hair growth by increasing hair elongation and melanin index after application for one month. Consequently, the PPE nanovesicles-loaded serum was effective for skin anti-aging and hair rejuvenation.

Formulation and Characterization of Herbal Ingredients based Shampoo

Shampoo is one of the cosmetic items that uses surfactants as its principal ingredient. When used as directed, the shampoo will clean the hair of surface grease, filth, and skin debris without having an unfavorable effect on the user. Shampoo is now used to promote hair growth and stop hair loss in addition to cleaning debris from the hair and scalp. The shampoo was prepared using amla extract, ritha extract, shikakai extract, bhringraja extract, henna extract, neem extract, and kalonji extract and evaluated for pH, wetting time, doaming properties, detergency ability, surface tension measurement, viscosity percent of solids, skin irritation test and stability test. It was concluded that sodium lauryl sulfate is very toxic to the hair. It damages the morphological integrity of the hair fiber, whereas natural conditioners protect hair morphological integrity and provides consistency and shine to hair.

In Vitro hair growth and hair tanning activities of mangosteen pericarp extract on hair dermal papilla cells

Premature hair graying and hair loss in men and women can cause a serious aesthetic problem. However, not much effective treatment is available, especially from natural sources. In this study, the efficacy of mangosteen pericarp water extract in promoting hair growth and tanning activities on hair dermal papilla cells was studied by using in vitro assays. The proliferation and cytotoxicity study on hair dermal papilla cells treated with mangosteen pericarp extract were measured by 3-(4,5-dimethylthiazol-2- yl)− 2,5-diphenyltetrazolium bromide (MTT) and Sulforhodamine B assay. The degree of hair dermal papilla cells proliferation increased with increasing concentration of the extract up to 500 μg/ml of extract treatment. The cell proliferation significantly increased by 157.56 % compared to the control with 500 μg/ml of extract treatment. The mangosteen pericarp extract was found to stimulate melanin synthesis and tyrosinase activity of hair dermal papilla cells in a concentration-dependent manner. The melanin synthesis in hair dermal papilla cells was upregulated more than four-fold with mangosteen pericarp extract as compared to the control group. The mangosteen pericarp extract was more potent and better in comparison with known effective melanogenic agents such as α-melanocyte stimulating hormone and forskolin in inducing the melanogenic effects of hair dermal papilla cells.

Hair Growth Regulation by Fibroblast Growth Factor 12 (FGF12)

The fibroblast growth factor (FGF) family has various biological functions, including cell growth, tissue regeneration, embryonic development, metabolism, and angiogenesis. In the case of hair growth, several members of the FGF family, such as FGF1 and FGF2, are involved in hair growth, while FGF5 has the opposite effect. In this study, the regulation of the hair growth cycle by FGF12 was investigated. To observe its effect, the expression of FGF12 was downregulated in mice and outer root sheath (ORS) by siRNA transfection, while FGF12 overexpression was carried out using FGF12 adenovirus. For the results, FGF12 was primarily expressed in ORS cells with a high expression during the anagen phase of hair follicles. Knockdown of FGF12 delayed telogen-to-anagen transition in mice and decreased the hair length in vibrissae hair follicles. It also inhibited the proliferation and migration of ORS cells. On the contrary, FGF12 overexpression increased the migration of ORS cells. FGF12-overexpressed ORS cells induced the telogen-to-anagen transition in the animal model. In addition, FGF12 overexpression regulated the expression of PDGF-CC, MDK, and HB-EGF, and treatment of these factors exhibited hair growth promotion. Altogether, FGF12 promoted hair growth by inducing the anagen phase of hair follicles, suggesting the potential for hair loss therapy.

Identification of Hair Growth Promoting Components in the Kernels of Prunus mira Koehne and Their Mechanism of Action.

The application of the seed oil of Prunus mira Koehne (Tibetan name ཁམབུ།), a plant belonging to the Rosaceae family, for the treatment of alopecia has been recorded in Jingzhu Materia Medica (ཤེལ་གོང་ཤེལ་ཕྲེང་།) (the classic of Tibetan medicine) and Dictionary of Chinese Ethnic Medicine. This study aims to reveal the effective components and mechanism of hair growth promotion in the kernel of Prunus mira Koehne. Network pharmacology was used to predict the mechanism of action and effective components in the treatment of the kernel of Prunus mira Koehne. The contents of amygdalin in 12 batches of the kernel of Prunus mira Koehne were determined by HPLC. An animal model of the depilation of KM mice induced by sodium sulfide was created, and five effective components that promoted hair growth were initially screened. In the study of the effectiveness and mechanism of action, KM and C57BL/6 mice are selected as experimental objects, three screening tests for active components of the kernel of P. mira are performed, and three effective components are screened out from the eight components. HE staining was used to detect the number of hair follicles and the thickness of the dermis. RT-PCR and immunohistochemistry were used to evaluate the influence of the expression of indicators in the Wnt/β-catenin signaling pathway in skin, including β-catenin, GSK-3β, and mRNA and protein expression levels of Cyclin D 1 and LEF 1. The network pharmacology study showed 12 signaling pathways involving 25 targets in the treatment of alopecia by the kernel of Prunus mira Koehne. vitamin E (3.125 mg/cm2/d), β-sitosterol (0.061 mg/cm2/d), and linoleic acid (0.156 mg/cm2/d) in the kernel of Prunus mira Koehne can promote hair growth in mice, and the mechanism of action may be related to the Wnt/β-catenin pathway.

Glycyrrhizin micellar nanocarriers for topical delivery of baicalin to the hair follicles: A targeted approach tailored for alopecia treatment

Alopecia affected approximately 16.6% of all people in China, however, treatment options remain limited due to the side effects. Plant bioactive compound baicalin (BC) possesses hair growth-promotion activity, but poor water solubility and unsuitable log P value restrict its topical application, and natural Glycyrrhizin (GL) can exactly overcome these drawbacks. Here, BC was encapsulated in GL to form GL-BC micelles for alopecia treatment. Simultaneously, tween 80 (TW) as carriers was incorporated in the GL-BC to form GL-TW-BC micelles. The topical penetration, penetration pathways, cellular uptake and the underlying mechanisms behind the hair loss reconstruction of the GL micelles were investigated. We found the optimal GL-BC and GL-TW-BC formulations significantly improved the penetration and accumulation of BC in the porcine skin predominantly through the hair follicles pathways without causing skin irritation, which resulted in a targeted treatment. The proliferation of human dermal papilla cells (hDPCs) and effective cellular uptake was also enhanced. Moreover, the activation of the Wnt/β-catenin pathway, up-expression of vascular endothelial growth factor (VEGF), α-melanocyte-stimulating hormone (α-MSH) and interleukin-10 (IL-10) were the mechanisms of micelles for the hair recovery. Interestingly, GL and BC exhibited a synergistic treatment of alopecia. Collectively, GL-BC and GL-TW-BC can be used as promising approaches for the treatment of alopecia.

Ficoll density gradient sedimentation isolation of pelage hair follicle mesenchymal stem cells from adult mouse back skin: a novel method for hair follicle mesenchymal stem cells isolation

BackgroundHair follicle mesenchymal stem cells (HF-MSCs) have great potential for cell therapy. Traditional method to isolate whisker HF-MSC is time-consuming and few in cell numbers. How to quickly and conveniently obtain a large number of HF-MSC for experimental research is a problem worth exploring.MethodsTwo-step Ficoll Density Gradient Sedimentation (FDGS) was performed to isolate pelage HF-MSC from adult mice. The characteristic of the isolated cells was identified and compared with whisker HF-MSC by immunofluorescence staining, flow cytometry, three-lineage differentiation and hair follicle reconstruction. Pelage HF-MSC and exosomes were injected into the dorsal skin of mice as well as hair follicle organ culture to explore its role in promoting hair growth. The cells and exosomes distribution were located by immunofluorescence staining.ResultsIsolated pelage HF-MSC expressed similar markers (ALP, Versican, NCAM, Nestin), showed similar growth pattern, possessed similar mesenchymal stem cells function and hair follicle induction ability as whisker HF-MSC. A large number of cells can be obtained with fewer mice compared to traditional method. Injected pelage HF-MSC promoted hair growth by secreting exosomes.ConclusionA large number of Pelage HF-MSC can be isolated by FDGS, which can promote hair growth by secreting exosomes which may target the dermal papilla and hair matrix region of host hair follicle.

Application of extracellular vesicles from mesenchymal stem cells promotes hair growth by regulating human dermal cells and follicles.

BACKGROUNDDermal papillae (DP) and outer root sheath (ORS) cells play important roles in hair growth and regeneration by regulating the activity of hair follicle (HF) cells.AIMTo investigate the effects of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) on DP and ORS cells as well as HFs. EVs are known to regulate various cellular functions. However, the effects of hMSC-EVs on hair growth, particularly on human-derived HF cells (DP and ORS cells), and the possible mechanisms underlying these effects are unknown. METHODShMSC-EVs were isolated and characterized using transmission electron micro scopy, nanoparticle tracking analysis, western blotting, and flow cytometry. The activation of DP and ORS cells was analyzed using cellular proliferation, migration, western blotting, and real-time polymerase chain reaction. HF growth was evaluated ex vivo using human HFs.RESULTSWnt3a is present in a class of hMSC-EVs and associated with the EV membrane. hMSC-EVs promote the proliferation of DP and ORS cells. Moreover, they translocate β-catenin into the nucleus of DP cells by increasing the expression of β-catenin target transcription factors (Axin2, EP2 and LEF1) in DP cells. Treatment with hMSC-EVs also promoted the migration of ORS cells and enhanced the expression of keratin (K) differentiation markers (K6, K16, K17, and K75) in ORS cells. Furthermore, treatment with hMSC-EVs increases hair shaft elongation in cultured human HFs.CONCLUSIONThese findings suggest that hMSC-EVs are potential candidates for further preclinical and clinical studies on hair loss treatment.

732 Treatment with cyclohexyl salicylate, an olfactory receptor 2A4/7 agonist, promotes human hair follicle growth and bulge stem cell progeny expansion

Topically applicable non-drugs that enhance the efficacy of available FDA-licensed drugs would be a welcome therapeutic addition in hair loss management. Since the olfactory receptor (OR) agonist, Sandalore, promotes human hair growth and reduces telogen effluvium, we have explored here whether other cosmetic OR ligands can unfold similar properties. We focused on OR2A4/7, since its stimulation promotes epidermal keratinocyte proliferation and differentiation. In situ hybridization showed that OR2A4/7 mRNA is widely expressed in the hair follicle (HF) epithelium, namely the outer root sheath (ORS) and hair matrix (HM). Yet, in freshly embedded human scalp skin, OR2A4/7 protein was mainly restricted to the infundibulum. However, OR2A4/7 protein became widely expressed in the ORS and HM during HF organ culture (OC), suggesting up-regulation of intrafollicular OR2A4/7 expression under tissue stress conditions. In scalp HF OC, the cosmetic OR2A4/7 agonist, cyclohexyl salicylate (CHS), delayed catagen development and tendentially increased HM proliferation. While CHS did not seem to impact on K15+ bulge stem cells, the % of CD34+ cells, i.e. their immediate progeny, was significantly increased in the suprabulbar ORS, as was the % of CD71+ transit amplifying cells (thought to derive from CD34+ cells) in the HM and suprabulbar ORS. Thus, stimulating OR2A4/7 via the non-drug CHS promotes hair growth and expands the progeny of K15+ stem cells, inviting the use of CHS as a novel cosmetic adjuvant treatment for hair loss disorders characterized by premature catagen development and a reduced capacity of K15+ stem cells to generate progeny, such as androgenetic alopecia.

601 Pharmacological inhibition of the chemokine receptor CX3CR1 promotes hair growth

Macrophages are located around hair follicles in normal skin and typically peak in density during the mid-telogen stage of the hair cycle. Hair follicles chemotactically attract macrophages and T cells and are in range to regulate hair follicle stem cells (HFSCs) quiescence, proliferation, and differentiation during physiologic and injured states. The expression of the fractalkine receptor CX3CR1 has been identified as a key regulator of macrophage and T cell migration and function at sites of inflammation.