Androgenetic Alopecia: Therapy Update

Ellagic acid inhibits dihydrotestosterone-induced ferroptosis and promotes hair regeneration by activating the wnt/β-catenin signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Androgenic alopecia (AGA) is the most prevalent form of hair loss in clinical practice and affects the physical and psychological well-being of adolescents. Paeonia lactiflora Pallas (PL), which is widely used in traditional Chinese medicine, enhances blood function and promotes hair growth, and ellagic acid (EA), a polyphenol in PL extract, shows strong antioxidant, anti-aging, and anti-inflammatory properties and also plays a role in the treatment of various skin conditions. However, its role and mechanism of action in AGA remain unclear.

AIM OF THE STUDY

To determine whether EA can rescue slow hair regeneration by regulating dihydrotestosterone (DHT)-induced ferroptosis in AGA mice and clarify the effect of EA on DHT-induced ferroptosis in dermal papilla cells (DPCs).

MATERIALS AND METHODS

Male C57BL/6 mice were used to establish a DHT-induced AGA mouse model, whereas DPCs were used to establish a DHT-induced cellular model. Thereafter, we investigated the therapeutic mechanism of action of EA via immunofluorescence, western blot analysis, immunohistochemistry, electron microscopy, and molecular docking.

RESULTS

EA stimulated hair regeneration in mice and reversed DHT-induced increases in iron content, lipid peroxidation, and DHT-induced mitochondrial dysfunction by activating the Wnt/β-catenin signaling pathway. Further, β-catenin knockdown suppressed the inhibitory effect of EA on DHT-induced ferroptosis in DPCs.

CONCLUSION

EA inhibits DHT-induced ferroptosis and promotes hair regrowth in mice by activating the Wnt/β-catenin signaling pathway. Thus, it has potential for use as a treatment option for AGA.

An Academic Dermatology Center's Structured Platelet-rich Plasma Approach to Patients with Androgenetic Alopecia

Androgenetic alopecia (AGA) is a prevalent cause of hair loss with complex pathophysiologic mechanisms that pose challenges for effective treatment. Despite various therapeutic approaches yielding only partial results, regenerative treatments, such as platelet-rich plasma (PRP), have gained popularity. However, the lack of standardized PRP practices, encompassing product preparation and application, has been a significant concern. This article aims to contribute to fill this gap by presenting a comprehensive overview of PRP practices at a large academic center. Through detailing our protocols, this work not only contributes to the understanding of AGA treatment but also emphasizes the crucial aspect of treatment standardization in the context of PRP therapy. By providing a practical representation of our institutional PRP practices, we aim to contribute to the ongoing discourse on refining and implementing standardized protocols, fostering reproducibility, and improving clinical outcomes in the management of AGA.

Thyroid receptor β: A promising target for developing novel anti-androgenetic alopecia drugs

Androgenetic alopecia (AGA) significantly impacts the self-confidence and mental well-being of people. Recent research has revealed that thyroid receptor β (TRβ) agonists can activate hair follicles and effectively stimulate hair growth. This review aims to comprehensively elucidate the specific mechanism of action of TRβ in treating AGA from various perspectives, highlighting its potential as a drug target for combating AGA. Moreover, this review provides a thorough summary of the research advances in TRβ agonist candidates with anti-AGA efficacy and outlines the structure-activity relationships (SARs) of TRβ agonists. We hope that this review will provide practical information for the development of effective anti-alopecia drugs.

Intradermal Injection in Balding Region Versus Intramuscular Injection in Surrounding Muscles: A Split-Scalp, Randomized Trial on BoNT for Androgenetic Alopecia

INTRODUCTION

Recent advancements in androgenetic alopecia (AGA) treatment have highlighted the efficacy of botulinum toxin (BoNT). However, inconsistencies in injection sites and depths warrant attention. It remains unclear which injection strategy is most beneficial for patients.

METHODS

This split-scalp randomized controlled trial divided each enrolled participant's scalp along the midline: one side was randomized to receive intramuscular BoNT injections in the surrounding muscles, while the other side received intradermal BoNT injections directly into the balding areas. This study evaluated the impact of treatment on hair density and diameter through trichoscopic examinations conducted at baseline and 12 weeks post treatment. Additionally, assessments of pain and overall safety were integrated into the study protocol.

RESULTS

Twenty-nine patients completed the study, with significant improvements in hair density observed in the intramuscular injection group compared to the intradermal group (p < 0.001). Both groups exhibited increases in hair diameter, but no significant difference was found between the two methods (p = 0.433). Pain evaluation revealed that intradermal injections in balding areas were more painful than intramuscular injections (p = 0.036), with no severe adverse reactions reported except for a single case of alopecia areata following injection.

CONCLUSION

Our research revealed that both BoNT injection strategies enhanced hair diameter 12 weeks post-treatment, with intramuscular injections significantly improving hair density more effectively. Despite the promising outcomes, the variability in patient responses underscores the necessity for personalized approaches and further research to refine injection protocols for optimized efficacy and safety.

TRIAL REGISTRATION NUMBER

ChiCTR2400080190.

Meta-Analysis of Efficacy of Platelet-Rich Plasma Combined with Minoxidil for Androgenetic Alopecia

BACKGROUND

Androgenetic alopecia (AGA) is a prevalent type of hair loss that impacts individuals of both genders. Platelet-rich plasma (PRP) and minoxidil have been employed as therapeutic interventions for AGA, yet the efficacy of their concurrent use remains ambiguous.

OBJECTIVE

To perform a comprehensive review and meta-analysis aimed at evaluating the effectiveness of platelet-rich plasma (PRP) in combination with minoxidil for the treatment of androgenetic alopecia (AGA).

METHODS

We conducted a comprehensive search of the databases PubMed, Embase, Web of Science, and Cochrane Library, encompassing their complete records up until December 2023. Eligible studies were randomized controlled trials that compared the combination of PRP and minoxidil with minoxidil or PRP alone in patients with AGA. The primary outcome measure was the change in hair growth as assessed by the hair density or hair thickness. Secondary outcome measures included patient satisfaction, and global photographic assessment.

RESULTS

A total of 6 studies involving 343 participants were included in this meta-analysis. The results showed that PRP combined with minoxidil significantly improved hair growth compared to minoxidil or PRP alone. The pooled analysis demonstrated a significant increase in hair density (weighted mean difference [WMD] = 9.14; 95% confidence interval [CI]: 6.57-11.70) and hair diameter (WMD = 4.72; 95% CI 3.21-6.23) in the PRP combined with minoxidil group. Moreover, patients receiving PRP combined with minoxidil reported higher satisfaction rates compared to those using minoxidil or PRP alone.

CONCLUSIONS

This meta-analysis suggests that PRP combined with minoxidil is an effective treatment for AGA, providing significant improvement in hair growth and patient satisfaction.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Autophagy Dysfunction: The Kernel of Hair Loss?

Autophagy is recognized as a crucial regulatory process, instrumental in the removal of senescent, dysfunctional, and damaged cells. Within the autophagic process, lysosomal digestion plays a critical role in the elimination of impaired organelles, thus preserving fundamental cellular metabolic functions and various biological processes. Mitophagy, a targeted autophagic process that specifically focuses on mitochondria, is essential for sustaining cellular health and energy balance. Therefore, a deep comprehension of the operational mechanisms and implications of autophagy and mitophagy is vital for disease prevention and treatment. In this context, we examine the role of autophagy and mitophagy during hair follicle cycles, closely scrutinizing their potential association with hair loss. We also conduct a thorough review of the regulatory mechanisms behind autophagy and mitophagy, highlighting their interaction with hair follicle stem cells and dermal papilla cells. In conclusion, we investigate the potential of manipulating autophagy and mitophagy pathways to develop innovative therapeutic strategies for hair loss.

Risk factors and lipid metabolism characteristics of early-onset male androgenetic alopecia: A pilot study

BACKGROUND

Male androgenetic alopecia (MAA) is a multifactorial disease, with patients presenting at a younger age, which is a risk factor for many metabolic diseases.

AIMS

To explore the risk factors associated with early-onset of MAA and its metabolic characteristics.

METHODS

Forty patients with MAA and 45 healthy controls were collected. The serum levels of fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total testosterone (TT), uric acid (UA), and 25-hydroxyvitamin D (25(OH)D) were measured. Meanwhile, lipid metabolites were detected by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).

RESULTS

37.50% MAA patients had metabolic syndrome, compared to 17.78% in control group (p < 0.05). The levels of HDL-C, UA, and 25(OH)D were decreased in patients with MAA compared to healthy controls (p < 0.05). However, there was no significant difference in the level of TT between the two groups. Additionally, there were no significant differences in the levels of HDL-C, UA, 25(OH)D, and TT among different grades of hair loss (p > 0.05). The lipid profile of early-onset MAA differed significantly from healthy controls. In early-onset MAA, the levels of ceramide (Cer) and sphingomyelin (SM) were significantly lower. Cer(d38:5) and TG(15:0/18:1/18:1) may be the biomarkers.

CONCLUSION

Low HDL-C, UA, and 25(OH)D may be the independent risk factors for early-onset MAA. Abnormal lipid metabolism was observed in early-onset MAA, wherein Cer and SM may serve as protective factors.

Phloroglucinol Enhances Anagen Signaling and Alleviates H2O2-Induced Oxidative Stress in Human Dermal Papilla Cells

Phloroglucinol (PG) is one of the abundant isomeric benzenetriols in brown algae. Due to its polyphenolic structure, PG exhibits various biological activities. However, the impact of PG on anagen signaling and oxidative stress in human dermal papilla cells (HDPCs) is unknown. In this study, we investigated the therapeutic potential of PG for improving hair loss. A non-cytotoxic concentration of PG increased anagen-inductive genes and transcriptional activities of β-Catenin. Since several anagen-inductive genes are regulated by β-Catenin, further experiments were performed to elucidate the molecular mechanism by which PG upregulates anagen signaling. Various biochemical analyses revealed that PG upregulated β-Catenin signaling without affecting the expression of Wnt. In particular, PG elevated the phosphorylation of protein kinase B (AKT), leading to an increase in the inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at serine 9. Treatment with the selective phosphoinositide 3-kinase/AKT inhibitor, LY294002, restored the increased AKT/GSK3β/β-Catenin signaling and anagen-inductive proteins induced by PG. Moreover, conditioned medium from PG-treated HDPCs promoted the proliferation and migration of human epidermal keratinocytes via the AKT signaling pathway. Subsequently, we assessed the antioxidant activities of PG. PG ameliorated the elevated oxidative stress markers and improved the decreased anagen signaling in hydrogen peroxide (H2O2)-induced HDPCs. The senescence-associated β-galactosidase staining assay also demonstrated that the antioxidant abilities of PG effectively mitigated H2O2-induced senescence. Overall, these results indicate that PG potentially enhances anagen signaling and improves oxidative stress-induced cellular damage in HDPCs. Therefore, PG can be employed as a novel therapeutic component to ameliorate hair loss symptoms.

Roles of gut microbiota in androgenetic alopecia: insights from Mendelian randomization analysis

Background

Androgenetic alopecia (AGA) is the most common type of androgen-associated hair loss. Previous studies have indicated an association between the gut microbiota and AGA. To delve deeper, we executed a two-sample Mendelian randomization (MR) analysis to investigate the potential causal relationship between the gut microbiota and AGA.

Methods

A two-sample MR investigation was utilized to delve into the intricate interplay between gut microbiota and AGA. Information regarding 211 gut microbial taxa was sourced from the MiBioGen consortium. The summary statistics of the genome-wide association studies (GWAS) for AGA were obtained from the FinnGen biobank, which included 195 cases and 201,019 controls. Various analytical approaches, including Inverse Variance Weighting (IVW), Weighted Median, MR-Egger, Weighted Mode, and Simple Mode were employed to evaluate the causal impact of gut microbiota on AGA. Sensitivity analyses were subsequently conducted to affirm the robustness of the findings.

Results

A two-sample MR investigation unveiled the genus Olsenella, genus Ruminococcaceae UCG-004, and genus Ruminococcaceae UCG-010 were identified as risk factors associated with AGA. In contrast, the family Acidaminococcaceae and genus Anaerofilum, along with the genus Ruminiclostridium 9, demonstrated a protective effect. The sensitivity analyses provided additional assurance that the findings of the current study were less susceptible to the influence of confounding variables and biases.

Conclusion

The MR study has established a link between specific gut microbiota and AGA, offering evidence for the identification of more precisely targeted probiotics. This discovery has the potential to aid in the prevention, control, and reversal of AGA progression.

Medical Treatment for Androgenetic Alopecia

Androgenetic alopecia is a common type of hair loss, which is generally influenced by genetic factors and systemic androgens resulting in follicular miniaturization.1 It can cause cosmetic problems leading to psychological distress among affected men and women. Effective standard medical treatments available are topical minoxidil 2 to 5%, oral finasteride, oral dutasteride, and hair transplantation.1 However, some patients do not achieve favorable results with standard treatments. For these reasons, other novel treatments have been developed, including new medications, regenerative medicines (autologous platelet-rich plasma, adipose-derived stem cells, micrograft generation, and exosome), and low-level laser therapy.

Utilising SNP Association Analysis as a Prospective Approach for Personalising Androgenetic Alopecia Treatment

INTRODUCTION

Androgenetic alopecia (AGA) is a prevalent, multifactorial form of hair loss involving complex aetiological factors, such as altered androgen regulation and energy metabolism. Existing treatments offer limited success, thus highlighting the need for advanced, personalised therapeutic strategies. This study focuses on correlating the genetic mechanisms of AGA with molecular targets involved in the response to current treatment modalities.

METHODS

An anonymised database including 26,607 patients was subjected to analysis. The dataset included information on patients' genotypes in 26 single nucleotide polymorphisms (SNPs), specifically, and diagnosed AGA grades, representing a broad range of ethnic backgrounds.

RESULTS

In our sample, 64.6% of males and 35.4% of females were diagnosed with female pattern hair loss. This distribution aligns well with prior studies, thus validating the representativeness of our dataset. AGA grading was classified using the Hamilton-Norwood and Ludwig scales, although no association was found to the grade of the disease. SNP association analysis revealed eight SNPs, namely rs13283456 (PTGES2), rs523349 (SRD5A2), rs1800012 (COL1A1), rs4343 (ACE), rs10782665 (PTGFR), rs533116 (PTGDR2), rs12724719 (CRABP2) and rs545659 (PTGDR2), to be statistically significant with a p-value below 0.05.

CONCLUSIONS

The study establishes a preliminary association between eight specific SNPs and AGA. These genetic markers offer insights into the variability of therapeutic responses, thus underlining the importance of personalised treatment approaches. Our findings show the potential for more targeted research to understand these SNPs' and further roles in AGA pathophysiology and in modulating treatment response.

Factors associated with early-onset androgenetic alopecia: A scoping review

BACKGROUND

Early-onset androgenetic alopecia (AGA) has been associated with various chronic conditions, including metabolic syndrome (MetS). Gaining a deep understanding of early-onset AGA may enable earlier intervention in individuals at high risks. This scoping review aims to explore the risk factors and etiology, associated conditions, and adverse effects on wellbeing in early-onset AGA.

METHODS

Electronic literature searches were conducted in MEDLINE, EMBASE and CENTRIAL. Eligible studies included case-control, cohort, cross-sectional, and meta-analysis studies. Selected studies needed to clearly define early-onset AGA cases or include only cases starting before the age of 40 and compare them with appropriate controls. The exclusion criteria comprised editorials, commentaries, case series, and non-systematic reviews, among others. Data extraction involved collecting study characteristics, methodologies, main outcomes, and findings. Descriptive tables were used to summarize key information and relevant variables when necessary.

RESULTS

Among the 65 eligible articles, 67.69% were case-control studies and 78.46% evaluated only male patients. "Early-onset" was defined as cases developing before the age of 30 years in 43.08% of the studies. The Hamilton-Norwood scale was the most frequently used method for evaluating the severity of alopecia in men (69.23%). Reported risk factors for early-onset AGA included a family history of AGA, cigarette smoking, unhealthy dietary habits, and a high body mass index. Early-onset AGA may also be associated with hormonal profiles, 5α-reductase enzyme activity, androgen receptor genes, and some susceptibility loci. Comorbidities investigated included MetS, cardiovascular disease, insulin resistance, dyslipidemia, and Parkinson's disease. Men with early-onset AGA may have reduced treatment efficacy with drug like rosuvastatin, metformin or lisinopril for dyslipidemia, prediabetes, or hypertension. Additionally, young men with AGA tended to suffer from psychological issues such as anxiety and low self-esteem compared to those without hair loss.

CONCLUSION

Early-onset AGA is a complex condition with various risk factors and etiology, associated comorbidities, and potential implications for treatment response and psychological health.

Serum lipidomic changes and sex differences in androgenetic alopecia

Background

Androgenetic alopecia (AGA) is the most common form of hair loss. Studies have suggested a potential link to metabolic disorders, but with conflicting results. To elucidate the lipidomics profile and sex-specific variations in AGA, while exploring correlation between AGA and metabolic syndrome (MetS).

Methods

The AGA patients (n = 83) and healthy controls (n = 84) were collected in the study. The lipid profiles were analyzed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Serum levels of important factors associated with AGA, namely dihydrotestosterone (DHT), prostaglandin D2 (PGD2) and transforming growth factor-β1 (TGF-β1) were quantified using ELISA.

Results

Compared with controls, AGA patients had a higher probability of MetS (26.51% vs 11.9%, P < 0.05). Fifty-one differentially expressed lipids were identified in AGA. The kind of triglyceride (TG) were significantly increased, while phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), and phosphatidylserine (PS) exhibited remarkable decrease. PC (16:2/21:6), PC (34:4p), PE (41:7), PE (44:12), PG (40:9), PI (32:2) and TG (15:0/18:1/18:1) were identified as potential biomarkers of AGA with the highest specificity. The levels of DHT, PGD2 and TGF-β1 were significantly elevated in AGA. All seven lipids showed significant correlations with DHT, PC (34:4p) and TG (15:0/18:1/18:1) were significantly associated with PGD2, TGF-β1 displayed exclusively correlation with TG (15:0/18:1/18:1) (all P < 0.05). Furthermore, these lipids were also significantly linked to systolic blood pressure and BMI, while some of them also showed significant associations with total cholesterol and HDL-C. In subgroups, forty-two differentially expressed lipids were identified in male AGA vs male control and eighty-one in female AGA vs female control. PC (16:2/21:6) was the only specific lipids common to both sexes.

Conclusions

Aberrant lipid metabolism was observed in AGA, with distinct lipidomic profiles between male and female AGA. The potential biomarkers were closely related to DHT, PGD2, TGF-β1 and MetS-related indicators. It provides the foundation for revealing the mechanisms of AGA.

Chitosan-polygalacturonic acid complex dressing improves diabetic wound healing and hair growth in diabetic mice

Chronic skin wounds decrease the quality of life of millions of diabetic patients worldwide. Chitosan has previously been shown to possess hemostatic properties, decrease inflammation, promote fibroblast proliferation, and hair growth. We developed a relatively low-cost polyelectrolyte complex (PEC) film dressing made of chitosan and polygalacturonic acid and tested it for its ability to accelerate diabetic wound healing. Genetically diabetic male mice were shaved on the dorsum, and one day later a 1 cm diameter full-thickness excisional wound was created. The PEC film was applied immediately after wounding and left in place for 14 days. Controls consisted of wounds treated with a fibrin gel. Wounds covered with the PEC film had closed completely by post-wounding day 42, while untreated wounds were only half-way closed. Histological analysis of wounds confirmed that PEC-treated wounds had fully re-epithelialized, while control wounds lacked a continuous epidermis at the wound center. We also observed that the area of skin under the PEC film experienced much more rapid hair growth. Histologically, there were significantly more hair follicles around the scar area (p < 0.05) in the PEC-treated group as compared to the control group. Thus, chitosan-polygalacturonic acid PEC films can accelerate both wound healing and hair growth in diabetic mice, and should be further investigated as a potential future treatment for diabetic chronic wounds.

Causal Effects of Lipids-Related Metabolites on Androgenic Alopecia: A Mendelian Randomization Study

Purpose

To investigate whether increased levels of lipids-related metabolites (LRMs) result in androgenic alopecia (AGA).

Patients and Methods

A two-sample Mendelian randomization (MR) study was designed, and single nucleotide polymorphisms (SNPs) respectively related to nine LRMs were selected from the genome-wide association study (GWAS) dataset. An MR analysis was performed to assess the causal association between LRMs and AGA.

Results

Through the fixed-effect inverse variance weighting (IVW) method, MR analysis indicated that Apolipoprotein B (ApoB), low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) had a causal relationship with AGA. No obvious heterogeneity or pleiotropy was observed.

Conclusion

The risk of AGA increases significantly when the serum levels of ApoB, LDL, and VLDL increase. This causal relationship is solid and free of interference from confounding factors.

Observing the clinical efficacy of combined serum microneedle therapy for moderate to severe androgenetic alopecia in scalp repair

OBJECTIVE

In this study, the safety and efficacy of scalp repair serum microneedles combined with oral drug administration and topical medication were investigated for the treatment of moderate to severe androgenetic alopecia.

METHODS

Twenty patients, consisting of 4 males and 16 females, who sought treatment for moderate to severe androgenetic alopecia at our hair medicine research center alopecia specialty clinic between August and December 2022 were randomly selected for the study. Male patients underwent oral administration of finasteride topical application of 5% minoxidil, and biweekly scalp repair serum microneedle therapy. Female patients were administered spironolactone or Diane-35 orally and applied 2% minoxidil topically, paired with biweekly scalp repair serum microneedle therapy sessions. After seven treatments, the scalp repair serum microneedle was discontinued, but oral administration and topical applications were continued, followed by a 1-month follow-up. Using a hair dermoscopy, hair follicles in a fixed region on the top of the head were manually counted per unit area to evaluate the hair restoration status of the patients quantitatively.

RESULTS

All 20 patients completed 3 months of combined therapy and a 1-month follow-up. On average, the patients experienced an increase of 42.6 hairs, with an efficiency rate of 100%. Significant differences were observed in hair count between any two of the first seven treatments (p < 0.001). A significant negative correlation was discovered between the initial pre-treatment hair count and the total improvement of hair (p < 0.001), indicating that the greater the degree of hair loss before treatment, the more pronounced the improvement.

CONCLUSION

Scalp repair serum microneedle combined therapy in moderate to severe androgenetic alopecia significantly reduces the number of microneedle treatments required, enhances treatment efficacy, and improves therapeutic outcomes.

Short-Term Clinical Assessment of Treating Female Androgenetic Alopecia with Autologous Stem Cells Derived from Human Hair Follicles

BACKGROUND

Androgenetic alopecia (AGA) is the most common form of alopecia, but treatment options are limited. This study evaluated clinical improvement in hair condition in women with AGA six months after a single injection of autologous cell micrografts (ACMs) containing hair follicle stem cells and dermal papilla cells.

METHODS

Twenty-three women with clinically and dermoscopy-confirmed AGA were included. Five 2.5 mm punch biopsies were taken from the skin of each patient with the Regenera device. The cell suspension was prepared with the Rigeneracons device and then injected into the hormone-dependent hairy zone of the scalp.

RESULTS

A significant improvement was observed on the visual analog scale (VAS) when comparing pre- and post-procedure photos (p < 0.001). The change in VAS scores was moderately negatively correlated with baseline ferritin concentration and positively with iron concentration. Improved outcomes were associated with higher baseline levels of sex hormone-binding globulin and 17α-hydroxyprogesterone. Neither testosterone nor DHT showed a significant correlation with VAS scores.

CONCLUSIONS

The ACM procedure was shown to be both safe and effective, yielding satisfying results six months after a single treatment session. Future investigations should aim to gather evidence that enables the development of a cost-effective approach while minimizing treatment burden and costs.

Active pharmaceutical ingredient-ionic liquids assisted follicular co-delivery of ferulic acid and finasteride for enhancing targeted anti-alopecia

Androgenetic alopecia (AGA) is the primary hair loss with impairing patients' quality of life. Finasteride (FIN) is an SRD5A2 inhibitor for AGA treatment, but oral FIN causes systemic adverse effects. Topical FIN delivery is anticipated to overcome this problem. Ferulic acid (FA) is a natural phenolic acid with vascular remodeling and anti-inflammatory effects. Herein, an active pharmaceutical ingredient ionic liquid (API IL) based on choline and FA (CF-IL) is for the first time constructed to load FIN for fabricating FIN CF-IL. CF-IL aims to act as carriers and cargos and enhance hair follicle (HF) co-delivery of FA and FIN for synergistic anti-alopecia. Thermal and spectroscopic analysis combined with quantum chemistry calculations and molecular dynamics confirm the formation of CF-IL. The CF-IL simultaneously increases the solubility of FA (∼648-fold) and FIN (∼686-fold), enhances the permeation and retention of FIN and FA through the follicular pathway, and promotes cellular uptake. FIN CFIL regulates the abnormal mRNA expressions in dihydrotestosterone-irritated hDPCs, and promotes hair regrowth in AGA mice in a combined manner with FIN and FA. These findings suggest that FA-based API IL is a promising approach for percutaneously co-delivering FA and FIN to HF, providing an enhanced targeting treatment for AGA.

Signaling pathways in hair aging

Hair follicle (HF) homeostasis is regulated by various signaling pathways. Disruption of such homeostasis leads to HF disorders, such as alopecia, pigment loss, and hair aging, which is causing severe health problems and aesthetic concerns. Among these disorders, hair aging is characterized by hair graying, hair loss, hair follicle miniaturization (HFM), and structural changes to the hair shaft. Hair aging occurs under physiological conditions, while premature hair aging is often associated with certain pathological conditions. Numerous investigations have been made to determine the mechanisms and explore treatments to prevent hair aging. The most well-known hypotheses about hair aging include oxidative stress, hormonal disorders, inflammation, as well as DNA damage and repair defects. Ultimately, these factors pose threats to HF cells, especially stem cells such as hair follicle stem cells, melanocyte stem cells, and mesenchymal stem cells, which hamper hair regeneration and pigmentation. Here, we summarize previous studies investigating the above mechanisms and the existing therapeutic methods for hair aging. We also provide insights into hair aging research and discuss the limitations and outlook.

Nanotechnology-based techniques for hair follicle regeneration

The hair follicle (HF) is a multicellular complex structure of the skin that contains a reservoir of multipotent stem cells. Traditional hair repair methods such as drug therapies, hair transplantation, and stem cell therapy have limitations. Advances in nanotechnology offer new approaches for HF regeneration, including controlled drug release and HF-specific targeting. Until recently, embryogenesis was thought to be the only mechanism for forming hair follicles. However, in recent years, the phenomenon of wound-induced hair neogenesis (WIHN) or de novo HF regeneration has gained attention as it can occur under certain conditions in wound beds. This review covers HF-specific targeting strategies, with particular emphasis on currently used nanotechnology-based strategies for both hair loss-related diseases and HF regeneration. HF regeneration is discussed in several modalities: modulation of the hair cycle, stimulation of progenitor cells and signaling pathways, tissue engineering, WIHN, and gene therapy. The HF has been identified as an ideal target for nanotechnology-based strategies for hair regeneration. However, some regulatory challenges may delay the development of HF regeneration nanotechnology based-strategies, which will be lastly discussed.

Comparing Current Therapeutic Modalities of Androgenic Alopecia: A Literature Review of Clinical Trials

Androgenic alopecia (AGA), commonly known as male pattern baldness (MPB), is a hereditary condition characterized by hair follicles that are sensitive to androgens. This article focuses on examining the recent advancements in the comprehension and management of AGA. The genetic factors and pathophysiology of AGA, including the role of dihydrotestosterone (DHT) and the androgen receptor gene, are discussed. The consequences of hair loss on self-esteem and identity, as well as on mental health, are examined. Diagnostic methods, such as the hair-pull test and trichoscopy, are discussed. The article also presents the Hamilton-Norwood classification, which is the most commonly employed system for classifying MPB. The article then delves into the various treatment options available, including topical minoxidil, oral finasteride, platelet-rich plasma therapy, low-level light therapy, hair transplant, and other alternative treatments. The efficacy and combination therapies for these treatments are examined. Additionally, emerging treatments such as caffeine-based solutions and prostaglandin inhibitors are discussed. By examining the recent advancements in AGA treatment, this article provides a comprehensive overview for healthcare professionals to make informed decisions when selecting the best treatment options for their patients.