Valproic acid induces hair regeneration in murine model and activates alkaline phosphatase activity in human dermal papilla cells

Therapeutic Potential of Stem Cells in Follicle Regeneration

Alopecia is caused by a variety of factors which affect the hair cycle and decrease stem cell activity and hair follicle regeneration capability. This process causes lower self-acceptance, which may result in depression and anxiety. However, an early onset of androgenic alopecia is associated with an increased incidence of the metabolic syndrome and an increased risk of the cardiac ischaemic disease. The ubiquity of alopecia provides an encouragement to seek new, more effective therapies aimed at hair follicle regeneration and neoregeneration. We know that stem cells can be used to regenerate hair in several therapeutic strategies: reversing the pathological mechanisms which contribute to hair loss, regeneration of complete hair follicles from their parts, and neogenesis of hair follicles from a stem cell culture with isolated cells or tissue engineering. Hair transplant has become a conventional treatment technique in androgenic alopecia (micrografts). Although an autologous transplant is regarded as the gold standard, its usability is limited, because of both a limited amount of material and a reduced viability of cells obtained in this way. The new therapeutic options are adipose-derived stem cells and stem cells from Wharton's jelly. They seem an ideal cell population for use in regenerative medicine because of the absence of immunogenic properties and their ease of obtainment, multipotential character, ease of differentiating into various cell lines, and considerable potential for angiogenesis. In this article, we presented advantages and limitations of using these types of cells in alopecia treatment.

Valproic Acid Induces Endothelial-to-Mesenchymal Transition-Like Phenotypic Switching

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is a widely used anticonvulsant drug that is currently undergoing clinical evaluation for anticancer therapy due to its anti-angiogenic potential. Endothelial cells (ECs) can transition into mesenchymal cells and this form of EC plasticity is called endothelial-to-mesenchymal transition (EndMT), which is widely implicated in several pathologies including cancer and organ fibrosis. However, the effect of VPA on EC plasticity and EndMT remains completely unknown. We report herein that VPA-treatment significantly inhibits tube formation, migration, nitric oxide production, proliferation and migration in ECs. A microscopic evaluation revealed, and qPCR, immunofluorescence and immunoblotting data confirmed EndMT-like phenotypic switching as well as an increased expression of pro-fibrotic genes in VPA-treated ECs. Furthermore, our data confirmed important and regulatory role played by TGFβ-signaling in VPA-induced EndMT. Our qPCR array data performed for 84 endothelial genes further supported our findings and demonstrated 28 significantly and differentially regulated genes mainly implicated in angiogenesis, endothelial function, EndMT and fibrosis. We, for the first time report that VPA-treatment associated EndMT contributes to the VPA-associated loss of endothelial function. Our data also suggest that VPA based therapeutics may exacerbate endothelial dysfunction and EndMT-related phenotype in patients undergoing anticonvulsant or anticancer therapy, warranting further investigation.

Androgens and androgen receptor action in skin and hair follicles

Beyond sexual functions, androgens exert their action in skin physiology and pathophysiology. Skin cells are able to synthesize most active androgens from gonadal or adrenal precursors and the enzymes involved in skin steroidogenesis are implicated both in normal or pathological processes. Even when the role of androgens and androgen receptor (AR) in skin pathologies has been studied for decades, their molecular mechanisms in skin disorders remain largely unknown. Here, we analyze recent studies of androgens and AR roles in several skin-related disorders, focusing in the current understanding of their molecular mechanisms in androgenetic alopecia (AGA). We review the molecular pathophysiology of type 2 5α-reductase, AR coactivators, the paracrine factors deregulated in dermal papillae (such as TGF-β, IGF 1, WNTs and DKK-1) and the crosstalk between AR and Wnt signaling in order to shed some light on new promising treatments.

In vivo monitoring of hair cycle stages via bioluminescence imaging of hair follicle NG2 cells

Hair growth occurs periodically in a cycle that consists of three different phases: growth, regression, and resting. The length of each phase is regulated by both intrinsic and extrinsic factors throughout life, and influenced by physiological and pathological conditions. Elongation of the resting phase and shortening of the growth phase occur during physiological ageing and in baldness, respectively. In vivo discrimination of each phase of the hair cycle can be used to research for regeneration of hair follicles as well as to evaluate the efficacy of hair regrowth treatments in the same individual. Here we show that NG2+ epithelial cells in the hair follicles encompass bulge stem cells, and that the number of hair follicle NG2 cells underwent dramatic changes during the hair cycle. Transgenic rats with expression of firefly luciferase gene in NG2 cells were generated to monitor the hair cycle in vivo. Hair follicle NG2 cells were clearly visualized via bioluminescence imaging to study each phase of the hair cycle in the rats, from infancy to old age.

Development of Pityriasis Amiantacea after Valproic Acid Therapy

Here, we present the case of a 16-year-old male who developed pityriasis amiantacea (PA) after the use of valproic acid. We propose that the keratinocyte proliferative activity of valproic acid mediated through the inhibition of glycogen synthase kinase-3β, and subsequent activation of the Wnt/β-catenin pathway could play a role in the development of PA. We additionally review the most relevant characteristics of this disease.

Valproate: It's Effects on Hair

Valproate is a drug used in the treatment of various seizure disorders, bipolar disorder, migraine prophylaxis, and off label in many indications by various specialists. The common adverse drug reactions reported on valproate administration are tremor, weight gain, gastrointestinal disturbances, liver dysfunction, metabolic acidosis, thrombocytopenia, and hair loss. An internet search with keywords “valproate” and “hair” was done on Google Search and PubMed for articles related to the topic. Recognition of cosmetically significant side effects on hair is necessary and neglect of which might result in poor compliance. Valproate-induced hair loss is diffused, nonscarring, and dose related. Other hair-related adverse events are curling of hair, graying, dirty appearance, and changes in texture. In contrast to oral ingestions causing hair loss, experiments with topical valproic acid have shown some initial evidence on hair regeneration. This makes valproate's effects on hair interesting and understanding it's effects on hair is very much essential in clinical practice.

Alopecia Areata: Review of Epidemiology, Clinical Features, Pathogenesis, and New Treatment Options

Alopecia areata (AA) is a complex autoimmune condition that causes nonscarring hair loss. It typically presents with sharply demarcated round patches of hair loss and may present at any age. In this article, we review the epidemiology, clinical features, pathogenesis, and new treatment options of AA, with a focus on the immunologic mechanism underlying the treatment. While traditional treatment options such as corticosteroids are moderately effective, a better understanding of the disease pathogenesis may lead to the development of new treatments that are more directed and effective against AA. Sources were gathered from PubMed, Embase, and the Cochrane database using the keywords: alopecia, alopecia areata, hair loss, trichoscopy, treatments, pathogenesis, and epidemiology.

Hair Germ Model In Vitro via Human Postnatal Keratinocyte-Dermal Papilla Interactions: Impact of Hyaluronic Acid

Hair follicle (HF) reconstruction in vitro is a promising field in alopecia treatment and human HF development research. Here, we combined postnatal human dermal papilla (DP) cells and skin epidermal keratinocytes (KCs) in a hanging drop culture to develop an artificial HF germ. The method is based on DP cell hair-inducing properties and KC self-organization. We evaluated two protocols of aggregate assembling. Mixed HF germ-like structures demonstrated the initiation of epithelial-mesenchymal interaction, including WNT pathway activation and expression of follicular markers. We analyzed the influence of possible DP cell niche components including soluble factors and extracellular matrix (ECM) molecules in the process of the organoid assembling and growth. Our results demonstrated that soluble factors had little impact on HF germ generation and Ki67⁺ cell score inside the organoids although BMP6 and VD3 maintained effectively the DP identity in the monolayer culture. Aggrecan, biglycan, fibronectin, and hyaluronic acid (HA) significantly stimulated cell proliferation in DP cell monolayer culture without any effect on DP cell identity. Most of ECM compounds prevented the formation of cell aggregates while HA promoted the formation of larger organoids. In conclusion, our model could be suitable to study cell-cell and cell-niche interactions during HF reconstruction in vitro.

Targeting of CXXC5 by a Competing Peptide Stimulates Hair Regrowth and Wound-Induced Hair Neogenesis

The Wnt/β-catenin pathway has been implicated in hair follicle development and hair regeneration in adults. We discovered that CXXC-type zinc finger protein 5 (CXXC5) is a negative regulator of the Wnt/β-catenin pathway involved in hair regrowth and wound-induced hair follicle neogenesis via an interaction with Dishevelled. CXXC5 was upregulated in miniaturized hair follicles and arrector pili muscles in human balding scalps. The inhibitory effects of CXXC5 on alkaline phosphatase activity and cell proliferation were demonstrated using human hair follicle dermal papilla cells. Moreover, CXXC5^-/- mice displayed accelerated hair regrowth, and treatment with valproic acid, a glycogen synthase kinase 3β inhibitor that activates the Wnt/β-catenin pathway, further induced hair regrowth in the CXXC5^-/- mice. Disrupting the CXXC5-Dishevelled interaction with a competitor peptide activated the Wnt/β-catenin pathway and accelerated hair regrowth and wound-induced hair follicle neogenesis. Overall, these findings suggest that the CXXC5-Dishevelled interaction is a potential target for the treatment of hair loss.

Androgenetic Alopecia: An Update of Treatment Options

Androgenetic alopecia (AGA) is characterized by a non-scarring progressive miniaturization of the hair follicle in predisposed men and women with a pattern distribution. Although AGA is a very prevalent condition, approved therapeutic options are limited. This article discusses the current treatment alternatives including their efficacy, safety profile, and quality of evidence. Finasteride and minoxidil for male androgenetic alopecia and minoxidil for female androgenetic alopecia still are the therapeutic options with the highest level evidence. The role of antiandrogens for female patients, the importance of adjuvant therapies, as well as new drugs and procedures are also addressed.

Valproic acid reduces hair loss and improves survival in patients receiving temozolomide-based radiation therapy for high-grade glioma

PURPOSE

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is also used to manage seizures in glioblastoma patients. HDAC inhibitors can protect normal cells and tissues from the deleterious effects of radiotherapy, and VPA is reported to improve the survival of glioblastoma patients receiving chemoradiation therapy. VPA also promotes hair growth, and thus has the potential to reduce the radiotherapy side effect of hair loss while improving the survival of patients with glioblastoma. The purpose of this study was to determine whether VPA use during radiotherapy for high-grade glioma is associated with decreased side effects of radiotherapy and an improvement in overall survival (OS) and progression-free survival (PFS).

METHODS

Medical records of 112 patients with high-grade glioma were retrospectively reviewed. We grouped patients by VPA use or non-use during radiotherapy, and evaluated hair loss, OS, and PFS.

RESULTS

The radiation dose and fractionation at the onset of hair loss were 4 Gy and two fractions higher, respectively, in the VPA group compared with the VPA non-use group (P < 0.01). Median OS was 42.2 and 20.3 months in the VPA use and non-use groups, respectively (P < 0.01; hazard ratio [HR], 0.36; 95% confidence interval [CI], 0.18-0.74). Median PFS was 22.7 and 11.0 months in the VPA use and non-use groups, respectively (P = 0.099; HR, 0.62; 95% CI, 0.36-1.09).

CONCLUSIONS

VPA use during radiotherapy for glioma is associated with delayed hair loss and improvement in survival. Hair loss prevention benefits patients suffering from the deleterious effects of radiation.

Characterization of Ovine Dermal Papilla Cell Aggregation

Context:

The dermal papilla (DP) is a condensation of mesenchymal cells at the proximal end of the hair follicle, which determines hair shaft size and regulates matrix cell proliferation and differentiation. DP cells have the ability to regenerate new hair follicles. These cells tend to aggregate both in vitro and in vivo. This tendency is associated with the ability of papilla cells to induce hair growth. However, human papilla cells lose their hair-inducing activity in later passage number. Ovine DP cells are different from human DP cells since they do not lose their aggregative behavior or hair-inducing activity in culture. Nonetheless, our understanding of ovine DP cells is still limited.

Aim:

The aim of this study was to observe the expression of established DP markers in ovine cells and their association with aggregation.

Subjects and Methods:

Ovine DP cells from three different sheep were compared. Histochemistry, immunoflourescence, and polymerase chain reaction experiments were done to analyze the DP markers.

Results:

We found that ovine DP aggregates expressed all the 16 markers evaluated, including alkaline phosphatase and versican. Expression of the versican V0 and V3 isoforms, neural cell adhesion molecule, and corin was increased significantly with aggregation, while hey-1 expression was significantly decreased.

Conclusions:

Overall, the stable expression of numerous markers suggests that aggregating ovine DP cells have a similar phenotype to papillae in vivo. The stability of their molecular phenotype is consistent with their robust aggregative behavior and retained follicle-inducing activity after prolonged culture. Their phenotypic stability in culture contrasts with DP cells from other species, and suggests that a better understanding of ovine DP cells might provide opportunities to improve the hair-inducing activity and therapeutic potential of human cells.

Polygonum aviculare L. and its active compounds, quercitrin hydrate, caffeic acid, and rutin, activate the Wnt/β-catenin pathway and induce cutaneous wound healing

Polygonum aviculare L. is a member of the Polygonaceae family of plants, which has been known for its antioxidant and anti-obesity effects. However, the wound healing function of P. aviculare extract has not been assessed. In this study, we identified a novel property of P. aviculare extract as a Wnt/β-catenin pathway activator based on a screen of 350 plant extracts using HEK293-TOP cells retaining the Wnt/β-catenin signaling reporter gene. P. aviculare extract accelerated the migration of HaCaT keratinocytes without showing significant cytotoxicity. Moreover, P. aviculare extract efficiently re-epithelized wounds generated on mice. Additionally, ingredients of P. aviculare extract, such as quercitrin hydrate, caffeic acid, and rutin, also accelerated the motility of HaCaT keratinocytes with the activation of Wnt/β-catenin signaling. Therefore, based on our findings, P. aviculare extract and its active ingredients could be potential therapeutic agents for wound healing. Copyright © 2016 John Wiley & Sons, Ltd.

Human placental extract exerts hair growth-promoting effects through the GSK-3β signaling pathway in human dermal papilla cells

Human placental extract (HPE) is widely used in Korea to relieve fatigue. However, its effects on human dermal papilla cells (hDPCs) remain unknown. In the present study, in an effort to develop novel therapies to promote hair growth, we screened HPE. We demonstrate that HPE has hair growth‑promoting activities and induces β‑catenin expression through the inhibition of glycogen synthase kinase‑3β (GSK‑3β) by phosphorylation in hDPCs. Treatment with HPE significantly increased the viability of the hDPCs in a concentration‑dependent manner, as shown by bromodeoxyuridine (BrdU) assay. HPE also significantly increased the alkaline phosphatase (ALP) expression levels. The increased β‑catenin levels and the inhibition of GSK‑3β (Ser9) by phosphorylation suggested that HPE promoted the hair-inductive capacity of hDPCs. We compared the effects of treatment with HPE alone and treatment with HPE in conjunction with minoxidil (MXD). We found that HPE plus MXD effectively inhibited GSK‑3β by phosphorylation (Ser9) in the hDPCs. Moreover, we demonstrated that HPE was effective in inducing root hair elongation in rat vibrissa hair follicles, and that treatment with HPE led to a delay in catagen progression. Overall, our findings suggest that HPE promotes hair growth and may thus provide the basis of a novel therapeutic strategy for the clinical treatment of hair loss.

A review of adipocyte lineage cells and dermal papilla cells in hair follicle regeneration

Alopecia is an exceedingly prevalent problem effecting men and women of all ages. The standard of care for alopecia involves either transplanting existing hair follicles to bald areas or attempting to stimulate existing follicles with topical and/or oral medication. Yet, these treatment options are fraught with problems of cost, side effects, and, most importantly, inadequate long-term hair coverage. Innovative cell-based therapies have focused on the dermal papilla cell as a way to grow new hair in previously bald areas. However, despite this attention, many obstacles exist, including retention of dermal papilla inducing ability and maintenance of dermal papilla productivity after several passages of culture. The use of adipocyte lineage cells, including adipose-derived stem cells, has shown promise as a cell-based solution to regulate hair regeneration and may help in maintaining or increasing dermal papilla cells inducing hair ability. In this review, we highlight recent advances in the understanding of the cellular contribution and regulation of dermal papilla cells and summarize adipocyte lineage cells in hair regeneration.

Emerging treatments in alopecia

INTRODUCTION

Alopecia is a common concern encountered in the medical practice. Treatment approach varies according to the type and severity of alopecia. However, available treatment options have limited efficacy and several adverse effects. Presently, there are different treatment options being studied to overcome these limitations. Additionally, cellular pathways involved in the pathophysiology of alopecia are further being clarified to potentially target pathogenic molecules.

AREAS COVERED

We searched the literature for recently published articles discussing new treatment options as well as mechanisms involved in alopecia. We discuss the use of stem cells, growth factors, cellular pathways and robotic hair transplant, among other emerging therapies used for alopecia.

EXPERT OPINION

Future looks very promising and new effective treatments such as janus kinase inhibitors could possibly be available for alopecia areata. The stem-cell technology is advancing and companies involved in hair follicle neogenesis are starting clinical trials on patients with androgenetic alopecia.

Preclinical toxicity of AZD7969: Effects of GSK3β inhibition in adult stem cells

AZD7969 is a potent inhibitor of glycogen synthase kinase 3 (GSK3β), which is a multifunctional serine/threonine kinase that negatively regulates the Wnt/β-catenin signaling pathway. Treatment of rats and dogs with AZD7969 for periods of up to 4 weeks resulted in a number of changes, the most significant of which was a dose-dependent, and treatment-related, increase in proliferation in a number of tissues that was thought to arise from derepression of Wnt/β-catenin signaling in the stem cell compartment. Phenotypically, this resulted in hyperplasia that either maintained normal tissue architecture in the gastrointestinal tract, liver, kidney, and adrenals or effaced normal tissue architecture within the bones, incisor teeth, and femorotibial joint. In addition to these changes, we noted a treatment-related increase in iron loading in the liver and proximal small intestines. This off-target effect was robust, potent, and occurred in both dogs and rats suggesting that AZD7969 might be a useful tool compound to study iron storage disorders in the laboratory.

Mycophenolate antagonizes IFN-γ-induced catagen-like changes via β-catenin activation in human dermal papilla cells and hair follicles

Recently, various immunosuppressant drugs have been shown to induce hair growth in normal hair as well as in alopecia areata and androgenic alopecia; however, the responsible mechanism has not yet been fully elucidated. In this study, we investigate the influence of mycophenolate (MPA), an immunosuppressant, on the proliferation of human dermal papilla cells (hDPCs) and on the growth of human hair follicles following catagen induction with interferon (IFN)-γ. IFN-γ was found to reduce β-catenin, an activator of hair follicle growth, and activate glycogen synthase kinase (GSK)-3β, and enhance expression of the Wnt inhibitor DKK-1 and catagen inducer transforming growth factor (TGF)-β2. IFN-γ inhibited expression of ALP and other dermal papillar cells (DPCs) markers such as Axin2, IGF-1, and FGF 7 and 10. MPA increased β-catenin in IFN-γ-treated hDPCs leading to its nuclear accumulation via inhibition of GSK3β and reduction of DKK-1. Furthermore, MPA significantly increased expression of ALP and other DPC marker genes but inhibited expression of TGF-β2. Therefore, we demonstrate for the first time that IFN-γ induces catagen-like changes in hDPCs and in hair follicles via inhibition of Wnt/β-catenin signaling, and that MPA stabilizes β-catenin by inhibiting GSK3β leading to increased β-catenin target gene and DP signature gene expression, which may, in part, counteract IFN-γ-induced catagen in hDPCs.

Targeting the Wnt pathways for therapies

The Wnt/β-catenin signaling pathway is crucial in animal development from sponges to humans. Its activity in the adulthood is less general, with exceptions having huge medical importance. Namely, improper activation of this pathway is carcinogenic in many tissues, most notably in the colon, liver and the breast. On the other hand, the Wnt/β-catenin signaling must be re-activated in cases of tissue damage, and insufficient activation results in regeneration failure and degeneration. These both medically important implications are unified by the emerging importance of this signaling pathway in the control of proliferation of various types of stem cells, crucial for tissue regeneration and, in case of cancer stem cells – cancer progression and relapse. This article aims at briefly reviewing the current state of knowledge in the field of Wnt signaling, followed by a detailed discussion of current medical developments targeting distinct branches of the Wnt pathway for anti-cancer and pro-regeneration therapies.

Targeting the Wnt pathways for therapies

The Wnt/β-catenin signaling pathway is crucial in animal development from sponges to humans. Its activity in the adulthood is less general, with exceptions having huge medical importance. Namely, improper activation of this pathway is carcinogenic in many tissues, most notably in the colon, liver and the breast. On the other hand, the Wnt/β-catenin signaling must be re-activated in cases of tissue damage, and insufficient activation results in regeneration failure and degeneration. These both medically important implications are unified by the emerging importance of this signaling pathway in the control of proliferation of various types of stem cells, crucial for tissue regeneration and, in case of cancer stem cells - cancer progression and relapse. This article aims at briefly reviewing the current state of knowledge in the field of Wnt signaling, followed by a detailed discussion of current medical developments targeting distinct branches of the Wnt pathway for anti-cancer and pro-regeneration therapies.

Treatment of MSCs with Wnt1a-conditioned medium activates DP cells and promotes hair follicle regrowth

Hair loss (alopecia) is a common problem for people. The dermal papilla is the key signaling center that regulates hair growth and it engage in crosstalk with the microenvironment, including Wnt signaling and stem cells. In this study, we explored the effects of bone marrow mesenchymal stem cell overexpression of Wnt1a on mouse hair follicle regeneration. Wnt-CM accelerated hair follicle progression from telogen to anagen and enhanced the ALP expression in the DP area. Moreover, the hair induction-related genes were upregulated, as demonstrated by qRT-PCR. Wnt-CM treatment restored and increased DP cell expression of genes downregulated by dihydrotestosterone treatment, as demonstrated by qRT-PCR assays. Our study reveals that BM-MSC-generated Wnt1a promotes the DP's ability to induce hair cycling and regeneration.

Alteration of skin properties with autologous dermal fibroblasts

Dermal fibroblasts are mesenchymal cells found between the skin epidermis and subcutaneous tissue. They are primarily responsible for synthesizing collagen and glycosaminoglycans; components of extracellular matrix supporting the structural integrity of the skin. Dermal fibroblasts play a pivotal role in cutaneous wound healing and skin repair. Preclinical studies suggest wider applications of dermal fibroblasts ranging from skin based indications to non-skin tissue regeneration in tendon repair. One clinical application for autologous dermal fibroblasts has been approved by the Food and Drug Administration (FDA) while others are in preclinical development or various stages of regulatory approval. In this context, we outline the role of fibroblasts in wound healing and discuss recent advances and the current development pipeline for cellular therapies using autologous dermal fibroblasts. The microanatomic and phenotypic differences of fibroblasts occupying particular locations within the skin are reviewed, emphasizing the therapeutic relevance of attributes exhibited by subpopulations of fibroblasts. Special focus is provided to fibroblast characteristics that define regional differences in skin, including the thick and hairless skin of the palms and soles as compared to hair-bearing skin. This regional specificity and functional identity of fibroblasts provides another platform for developing regional skin applications such as the induction of hair follicles in bald scalp or alteration of the phenotype of stump skin in amputees to better support their prosthetic devices.

Topical valproic acid increases the hair count in male patients with androgenetic alopecia: a randomized, comparative, clinical feasibility study using phototrichogram analysis

Valproic acid (VPA), a widely used anticonvulsant, inhibits glycogen synthase kinase 3β and activates the Wnt/β-catenin pathway, which is associated with hair growth cycle and anagen induction. To assess the efficacy of topical VPA for treating androgenetic alopecia (AGA), we performed a randomized, double-blind, placebo-controlled clinical trial. Male patients with moderate AGA underwent treatment with either VPA (sodium valproate, 8.3%) or placebo spray for 24 weeks. The primary end-point for efficacy was the change in hair count during treatment, which was assessed by phototrichogram analysis. Of the 40 patients enrolled in the study, 27 (n = 15, VPA group; n = 12, placebo group) completed the entire protocol with good compliance. No statistical differences in age, hair loss duration and total hair count at baseline were found between the groups. The mean change in total hair count was significantly higher in the VPA group than in the placebo group (P = 0.047). Both groups experienced mostly mild and self-limited adverse events, but their differences in prevalence rates were similar between the two groups (P = 0.72). A subject treated with topical VPA developed ventricular tachycardia, but it did not seem to be related to the VPA spray. Topical VPA increased the total hair counts of our patients; therefore, it is a potential treatment option for AGA.

Safety evaluation of topical valproate application

The potential role of topical valproate (VPA) in hair regrowth has been recently suggested. However, safety reports of VPA as a topical formulation are lacking. Therefore, in the present study, we investigated whether VPA causes skin irritation in humans. We first performed a cell viability test and showed that VPA did not exhibit toxicity toward HaCaT keratinocytes, fibroblasts, and RBL-3H mast cells. We then performed clinical patch test and skin irritation test through transdermal drug delivery with the help of microneedle rollers. No significant findings were obtained in the clinical patch test. In the skin irritation test, only 1 patient showed erythema at 1 hr, but the irritation reaction faded away within a few hours. Erythema and edema were not observed at 24 hr. We concluded that VPA has minimal potential to elicit skin irritation. Therefore, we consider that VPA can safely be applied to human skin.

A rapid and highly sensitive UPLC-MS/MS method using pre-column derivatization with 2-picolylamine for intravenous and percutaneous pharmacokinetics of valproic acid in rats

A rapid, highly sensitive and specific ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) for the detection of valproic acid (VPA) in rat plasma following the topical application was developed and validated. This method was carried out with pre-column derivatization using 2-picolylamine (PA) which reacts with the carboxylic acid group of VPA. The derivatization was completed in 10min and the resulting PA-VPA derivative enabled the sensitive detection of VPA in selected reaction monitoring (SRM) mode. Sample preparation was done with simple liquid-liquid extraction and chromatographic separation was achieved within 5min on a C18 column using a gradient elution with the mobile phase of 2mM ammonium formate containing 0.1% formic acid and methanol. The standard curves were linear over the concentration range of 0.07-200μg/mL with a correlation coefficient higher than 0.99. The limit of detection (LOD) and the lower limit of quantification (LLOQ) was 0.03 and 0.07μg/mL, respectively with 100μL of plasma sample. The intra- and inter-day precisions were measured to be below 10.7% and accuracies were within the range of 94.1-115.9%. The validated method was successfully applied to the pharmacokinetics of VPA in the rat following topical and intravenous applications.

Valproic acid promotes human hair growth in in vitro culture model

BACKGROUND

β-Catenin, the transducer of Wnt signaling, is critical for the development and growth of hair follicles. In the absence of Wnt signals, cytoplasmic β-catenin is phosphorylated by glycogen synthase kinase (GSK)-3 and then degraded. Therefore, inhibition of GSK-3 may enhance hair growth via β-catenin stabilization. Valproic acid is an anticonvulsant and a mood-stabilizing drug that has been used for decades. Recently, valproic acid was reported to inhibit GSK-3β in neuronal cells, but its effect on human hair follicles remains unknown.

OBJECTIVES

To determine the effect of VPA on human hair growth.

METHODS

We investigated the effect of VPA on cultured human dermal papilla cells and outer root sheath cells and on an in vitro culture of human hair follicles, which were obtained from scalp skin samples of healthy volunteers. Anagen induction by valproic acid was evaluated using C57BL/6 mice model.

RESULTS

Valproic acid not only enhanced the viability of human dermal papilla cells and outer root sheath cells but also promoted elongation of the hair shaft and reduced catagen transition of human hair follicles in organ culture model. Valproic acid treatment of human dermal papilla cells led to increased β-catenin levels and nuclear accumulation and inhibition of GSK-3β by phosphorylation. In addition, valproic acid treatment accelerated the induction of anagen hair in 7-week-old female C57BL/6 mice.

CONCLUSIONS

Valproic acid enhanced human hair growth by increasing β-catenin and therefore may serve as an alternative therapeutic option for alopecia.

New investigational drugs for androgenetic alopecia

INTRODUCTION

Androgenetic alopecia (AGA) is the most common form of hair loss, however current treatment options are limited and moderately effective. In the past few years, there has been an increased interest in deciphering the molecular mechanisms responsible for this disorder, which has opened the possibility of novel treatments that promise to not only stimulate hair growth, but also to induce formation of new hair follicles.

AREAS COVERED

The future holds more effective topical treatments with less systemic side effects (such as topical 5-alfa-reductase inhibitors), prostaglandin analogs and antagonists, medications which act through the Wnt signaling pathway, stem cells for hair regeneration, platelet-rich plasma (PRP) and more effective ways of transplanting hair. A comprehensive search was made using PubMed, GoogleScholar and Clinicaltrial.gov using different combination of key words, which included AGA treatment, new treatments for AGA, Wnt pathway, prostaglandins, PRP and stem cells for hair regrowth.

EXPERT OPINION

In the near future, treatments with topical 5-alfa-reductase inhibitors and prostaglandin agonists or antagonists are expected. More evidence is needed to verify the efficacy of PRP. Although hair follicle bioengineering and multiplication is a fascinating and promising field, it is still a long way from being available to clinicians.

Valproic acid induces cutaneous wound healing in vivo and enhances keratinocyte motility

Background

Cutaneous wound healing is a complex process involving several signaling pathways such as the Wnt and extracellular signal-regulated kinase (ERK) signaling pathways. Valproic acid (VPA) is a commonly used antiepileptic drug that acts on these signaling pathways; however, the effect of VPA on cutaneous wound healing is unknown.

Methods and Findings

We created full-thickness wounds on the backs of C3H mice and then applied VPA. After 7 d, we observed marked healing and reduced wound size in VPA-treated mice. In the neo-epidermis of the wounds, β-catenin and markers for keratinocyte terminal differentiation were increased after VPA treatment. In addition, α-smooth muscle actin (α-SMA), collagen I and collagen III in the wounds were significantly increased. VPA induced proliferation and suppressed apoptosis of cells in the wounds, as determined by Ki67 and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining analyses, respectively. In vitro, VPA enhanced the motility of HaCaT keratinocytes by activating Wnt/β-catenin, ERK and phosphatidylinositol 3-kinase (PI3-kinase)/Akt signaling pathways.

Conclusions

VPA enhances cutaneous wound healing in a murine model and induces migration of HaCaT keratinocytes.