Observations that suggest a contribution of altered dermal papilla mitochondrial function to androgenetic alopecia

Hair Longevity-Evidence for a Multifactorial Holistic Approach to Managing Hair Aging Changes

Loss of hair density-hair thinning and balding- is typically referred to as male and female pattern alopecia. Causes include genetic predisposition and links to the impact of dihydrotestosterone on the follicle dermal papilla, which are typically characterized by an increase in the number of vellus follicles. Links to chronological aging are unclear. Proven treatments remain few in number and are still targeting and tested on those experiencing classical pattern hair loss. The way hair changes with aging, especially in women, can be considered as having a much broader scope. Trends in managing changes to hair density, length, and fiber quality with aging now mostly include cocktail approaches-whether topical, injected, or oral-recognizing that solutions are more likely to require a multifactorial strategy. This review examines the evidence for the more holistic approach to addressing unwanted hair loss, which includes nutrition, lifestyle, stress management, and scalp and hair care, as well as co-morbidities with other health concerns. We discuss the strengths and limitations of clinical study design to investigate efficacy using multifactorial holistic approaches. We propose that this strategy will contribute to the emerging concept of hair longevity in which follicle, scalp, and fiber are targeted and that maintaining anagen is the most appropriate route to achieving healthy hair with aging. Finally, we discuss the problem facing patients and consumers regarding the quantity of misinformation and how it influences choosing from a fast-growing market of solutions that bypass a pharmaceutical approach to hair thinning.

Gas-propelled anti-hair follicle aging microneedle patch for the treatment of androgenetic alopecia

Existing treatments for androgenetic alopecia (AGA) are unsatisfactory, owing to the two major reasons: (1) Oxidative stress and vascularization deficiency in the perifollicular microenvironment provoke the premature senescence of hair follicles, limiting the transformation of hair growth cycle from the telogen to the anagen phase; (2) The amount of drug delivered to the perifollicular region located in the deep dermis is very limited for passive drug delivery systems. Herein, we developed a gas-propelled microneedle patch integrated with ferrum-chelated puerarin/quercetin nanoparticles (PQFN) to increase drug accumulation in hair follicles and reshape the perifollicular microenvironment for improved hair-regenerating effects. PQFN can rejuvenate testosterone (Tes)-induced senescence of dermal papilla cells by scavenging ROS, restoring mitochondrial function, regulating signaling pathways related to hair regeneration, and upregulating hair growth-promoting genes. PQFN more efficiently promoted endothelial cell proliferation, migration, and tube formation than ferrum-chelated quercetin nanoparticles (QFN) because of puerarin's proangiogenic effects. Compared with passive MNs, gas-propelled MNs promoted drug diffusion and permeation into deeper skin layers, resulting in significantly higher drug accumulation in hair follicles. Pharmacodynamic studies on an AGA mouse model further showed that PQFN-loaded active MNs achieved higher hair coverage by alleviating oxidative stress, promoting angiogenesis, and rejuvenating senescent cells. Therefore, this study presents a novel "anti-hair follicle aging" treatment strategy for AGA.

Immune and Non-immune Interactions in the Pathogenesis of Androgenetic Alopecia

Androgenetic alopecia (AGA), a leading cause of progressive hair loss, affects up to 50% of males aged 50 years, causing significant psychological burden. Current treatments, such as anti-androgen drugs and minoxidil, show heterogeneous effects, even with long-term application. Meanwhile, the large-scale adoption of other adjuvant therapies has been slow, partly due to insufficient mechanistic evidence. A major barrier to developing better treatment for AGA is the incomplete understanding of its pathogenesis. The predominant academic consensus is that AGA is caused by abnormal expression of androgens and their receptors in individuals with a genetic predisposition. Emerging evidence suggests the contributing role of factors such as immune responses, oxidative stress, and microbiome changes, which were not previously given due consideration. Immune-mediated inflammation and oxidative stress disrupt hair follicles' function and damage the perifollicular niche, while scalp dysbiosis influences local metabolism and destabilizes the local microenvironment. These interconnected mechanisms collectively contribute to AGA pathogenesis. These additional aspects enhance our current understanding and confound the conventional paradigm, bridging the gap in developing holistic solutions for AGA. In this review, we gather existing evidence to discuss various etiopathogenetic factors involved in AGA and their possible interconnections, aiming to lay the groundwork for the future identification of therapeutic targets and drug development. Additionally, we summarize the advantages and disadvantages of AGA research models, ranging from cells and tissues to animals, to provide a solid basis for more effective mechanistic studies.

Progress on mitochondria and hair follicle development in androgenetic alopecia: relationships and therapeutic perspectives

Hair loss has long been a significant concern for many individuals. Recent studies have indicated that mitochondria play a more crucial role in hair loss than previously recognized. This review summarizes the connection between mitochondrial dysfunction and hair follicle development, outlines the links between diseases related to mitochondrial disorders and hair issues, and highlights the influence of mitochondrial dysfunction on androgenetic alopecia. We discuss the cellular and signaling mechanisms associated with hair loss and examine how mitochondrial dysfunction, such as insufficient energy supply, signaling irregularities, protein/gene abnormalities, and programmed cell death, can hinder the normal proliferation, differentiation, and growth of hair follicle cells. Furthermore, we discuss current treatment approaches and potential innovative therapies, including mitochondrion-targeting drugs and advanced techniques that directly target hair follicle cells, providing fresh insights into the crucial role of mitochondria in maintaining hair follicle health and managing hair disorders. Furthermore, this review explores future therapeutic strategies and proposes that mitochondrial research could lead to groundbreaking treatments for hair loss, thus providing optimism and new avenues for the treatment of individuals experiencing hair loss. This review not only underscores the central importance of mitochondria in hair health but also emphasizes the importance of advancing research and treatment in this field.

Resveratrol-Loaded Versatile Nanovesicle for Alopecia Therapy via Comprehensive Strategies

Introduction

Alopecia is a systemic disease with multiple contributing factors. Effective treatment is challenging when only hair growth mechanisms are targeted while ignoring the role of maintaining hair follicle microenvironment homeostasis, which is crucial for cell growth and angiogenesis. Oxidative stress and inflammation are major disruptors of this microenvironment, leading to inhibited cell proliferation and compromised hair follicle circulation. Drugs with antioxidant and anti-inflammatory effects could potentially restore microenvironment homeostasis, offering a promising strategy for alopecia treatment.

Methods

Resveratrol (RES), a potent antioxidant and anti-inflammatory agent, was selected as the model drug and encapsulated into an active carrier-PPD-Lip to create PPD-Lip@RES. The efficacy of PPD-Lip@RES was comprehensively evaluated in both in vitro and in vivo aspects, and its underlying mechanism was also primarily explored.

Results

PPD-Lip@RES promoted the proliferation and migration of dermal papilla cells, up-regulated the expression of positive hair growth regulators, and facilitated angiogenesis. It also activated hair follicle stem cells by increasing the expression of Ki67, K5, β-catenin, CD31, and CK19. In the telogen effluvium model, PPD-Lip@RES resulted in more robust hair regeneration, with less hair shedding compared to the minoxidil group. Furthermore, it showed significant therapeutic effects in severe androgenetic alopecia, outperforming finasteride and even the healthy control group.

Conclusion

The results suggested that PPD-Lip@RES, as a systemic intervention strategy, could effectively facilitate hair growth by targeting both the pathological and physiological processes involved in hair loss. Its superior performance in both telogen effluvium and androgenetic alopecia models indicates its potential as an advanced treatment option for alopecia.

Molecular monitoring of short- and long-term transcriptional effects of hair growth stimulating agents

Male-pattern hair loss (MPHL) is the most common form of hair loss in humans. Limited treatment options exist, which are not curative and vary in efficacy and invasiveness. Therapeutic and cosmetic hair growth stimulating agents that alleviate hair loss at a low risk of side effects are therefore of interest. The efficacy of hair growth-stimulating agents is mainly evaluated by hair comb tests and trichograms. These methods do not offer molecular insights, which can provide early insights into treatment response and may be useful in monitoring long-term compliance and efficacy. We propose a general concept for the molecular monitoring of hair growth stimulating agent treatment response in vivo, based on RNA and microRNA expression profiling before and during treatment. The molecular profile can be extended by individual genotype information to assess the impact of genetic constitution on treatment response. To test this methodological approach, 91 male participants with visible signs of and/or a family history of MPHL were assigned to four groups to investigate the effects of three hair growth stimulating agents versus placebo. mRNA- and microRNA-Seq was performed on plucked hair follicle samples before, after four days, and after six weeks of treatment. Genotyping was performed on DNA extracted from blood or saliva samples. Differential expression analyses identified 52 differentially expressed genes and 17 modulated pathways following treatment with the three hair growth stimulating agents. While the majority of effects were detectable after 6-week treatment, 23% of genes showed significant regulation after 4-day treatment. Integration with genetic data through pathway-based polygenic risk score analyses identified 5 associations between genetic background and treatment effects, pointing to a potential value of companion diagnostics for hair growth stimulating agents. Our data show that this molecular monitoring approach provides insights into hair growth stimulating agent treatment response as early as days within commencing treatment, and is suitable to monitor long-term treatment effects and compliance. Combined with genetic profiling, this approach may enable personalized prediction of treatment efficacy and compliance.

Blue light inhibits cell viability and proliferation in hair follicle stem cells and dermal papilla cells

Hair loss is a prevalent issue worldwide, which, though not life-threatening, can result in psychological problems, low self-esteem, and social anxiety. Previous studies have shown that ultraviolet radiation can have negative effects on hair follicle cells, leading to hair loss, while the impact of blue light on hair and hair follicle has largely been overlooked. This study aimed to examine the effects of blue light on hair follicle stem cells (HFSCs) and primary dermal papilla cells (DPCs), which are essential components of hair follicles. Human HFSCs and primary DPCs were exposed to blue light (457 nm) at various intensities (1, 4, 8, and 16 mW/cm2) for 3 days. Subsequently, cell viability, cell proliferation, and intracellular reactive oxygen species (ROS) were assessed. The results showed that blue light (457 nm) significantly reduced the cell viability and proliferation of HFSCs and DPCs in vitro, with the inhibition being intensity-dependent. Additionally, blue light triggered the overproduction of ROS in the DPCs. While the exact mechanisms by which blue light affects hair follicle cells remain unclear, these findings suggest that blue light could impede the growth of these cells. This insight may offer a new approach to protecting hair by avoiding exposure to high-intensity blue light.

Mitochondrial-related genes as prognostic and metastatic markers in breast cancer: insights from comprehensive analysis and clinical models

Background

Breast cancer (BC) constitutes a significant peril to global women's health. Contemporary research progressively suggests that mitochondrial dysfunction plays a pivotal role in both the inception and advancement of BC. However, investigations delving into the correlation between mitochondrial-related genes (MRGs) and the prognosis and metastasis of BC are still infrequent.

Methods

Utilizing data from the TCGA database, we employed the "limma" R package for differential expression analysis. Subsequently, both univariate and multivariate Cox regression analyses were executed, alongside LASSO Cox regression analysis, to pinpoint prognostic MRGs and to further develop the prognostic model. External validation (GSE88770 merged GSE425680) and internal validation were further conducted. Our investigation delved into a broad spectrum of analyses that included functional enrichment, metabolic and immune characteristics, immunotherapy response prediction, intratumor heterogeneity (ITH), mutation, tumor mutational burden (TMB), microsatellite instability (MSI), cellular stemness, single-cell, and drug sensitivity analysis. We validated the protein and mRNA expressions of prognostic MRGs in tissues and cell lines through immunohistochemistry and qRT-PCR. Moreover, leveraging the GSE102484 dataset, we conducted differential gene expression analysis to identify MRGs related to metastasis, subsequently developing metastasis models via 10 distinct machine-learning algorithms and then selecting the best-performing model. The division between training and validation cohorts was set at 70% and 30%, respectively.

Results

A prognostic model was constructed by 9 prognostic MRGs, which were DCTPP1, FEZ1, KMO, NME3, CCR7, ISOC2, STAR, COMTD1, and ESR2. Patients within the high-risk group experienced more adverse outcomes than their counterparts in the low-risk group. The ROC curves and constructed nomogram showed that the model exhibited an excellent ability to predict overall survival (OS) for patients and the risk score was identified as an independent prognostic factor. The functional enrichment analysis showed a strong correlation between metabolic progression and MRGs. Additional research revealed that the discrepancies in outcomes between the two risk categories may be attributed to a variety of metabolic and immune characteristics, as well as differences in intratumor heterogeneity (ITH), tumor mutational burden (TMB), and cancer stemness indices. ITH, TIDE, and IPS analyses suggested that patients possessing a low-risk score may exhibit enhanced responsiveness to immunotherapy. Additionally, distant metastasis models were established by PDK4, NRF1, DCAF8, CHPT1, MARS2 and NAMPT. Among these, the XGBoost model showed the best predicting ability.

Conclusion

In conclusion, MRGs significantly influence the prognosis and metastasis of BC. The development of dual clinical prediction models offers crucial insights for tailored and precise therapeutic strategies, and paves the way for exploring new avenues in understanding the pathogenesis of BC.

Androgenic alopecia is associated with higher dietary inflammatory index and lower antioxidant index scores

Background

Androgenic alopecia (AGA), the most prevalent hair loss type, causes major psychological distress and reduced quality of life. A definite and safe cure/prevention for this condition is still lacking. The role of oxidative stress and inflammation in AGA pathogenesis prompted us to investigate the association between dietary antioxidant index (DAI) and energy-adjusted dietary inflammatory index (E-DII) with AGA.

Methods

The investigation was designed based on data from 10,138 participants from the Fasa Adult Cohort Study (FACS). DAI and energy-adjusted DII (E-DII) were calculated utilizing a validated 125-item food frequency questionnaire (FFQ). A physician diagnosed AGA. Logistic regression models were utilized to evaluate the association of DAI and E-DII with AGA.

Results

After exclusion, 9,647 participants (44.0% men, mean age: 48.6 ± 9.5 years) consisting of 7,348 participants with AGA entered the analyses. Higher DAI was associated with 10% lower AGA odds, while higher E-DII showed 4% higher AGA odds after adjusting for various confounding variables. However, significant associations were found only among women, and adjusting for metabolic syndrome (MetS) made the E-DII-AGA association insignificant.

Conclusion

Antioxidant-rich diets protect against AGA, while pro-inflammatory diets increase the risk, likely through developing MetS. Patient nutrition is frequently overlooked in clinical practice, yet it plays a crucial role, especially for women genetically predisposed to androgenetic alopecia. Dietary changes, such as reducing pro-inflammatory foods (like trans and saturated fats) and increasing anti-inflammatory options (fruits and vegetables), can help prevent hair loss and mitigate its psychological impacts, ultimately lowering future treatment costs.

Topical Minoxidil Rejuvenates Hair Follicles from Men with Androgenetic Alopecia in Vivo

Abstract is missing (Short communication)

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.

Divergent progression pathways in male androgenetic alopecia and female pattern hair loss: Trichoscopic perspectives

BACKGROUND

Despite similarities in progressive miniaturization of hair follicles and transition of terminal hairs to vellus hairs, insufficient trichoscopic comparisons between male androgenetic alopecia (MAGA) and female pattern hair loss (FPHL) hinder our ability to select effective treatments.

AIM

Our study aimed to explore gender-specific trichoscopic characteristics of MAGA and FPHL, while formulating hypotheses regarding the progression of these conditions across clinical stages.

METHODS

We classified 126 male MAGA subjects using Hamilton-Norwood Classification and 57 FPHL subjects using adopted Sinclair Scale. Subsequently, we analyzed nine trichoscopic factors divided into three categories: hair-diameter related, hair-number per follicular unit related, and hair density related factors.

RESULTS

Of the nine quantitative trichoscopic factors, hair-diameter and hair-number per follicular unit showed strong correlations with clinical stages in both genders. Hair density, a common trichoscopic factor for hair loss evaluation, weakly correlated with clinical stages in FPHL, but not at all in MAGA. In addition, MAGA was characterized by a progressive reduction in hair-diameter, followed by a reduction in hair-number per follicular unit. FPHL, on the contrary, showed the opposite progression.

CONCLUSIONS

Trichoscopic factors vary with disease severity in a gender-specific manner. Our research highlights that MAGA and FPHL involve two distinct streams: hair-diameter decreasing by hair follicle miniaturization (Stream 1), and hair-number per follicular unit decreasing by hair follicle tri-lineage niche dysfunction (Stream 2). MAGA typically starts from Stream 1 to Stream 2, while FPHL starts from Stream 2. These diverse progression pathways underscore the importance of personalized treatment approaches.

The exploration of mitochondrial-related features helps to reveal the prognosis and immunotherapy methods of colorectal cancer

BACKGROUND

Cancer cell survival, proliferation, and metabolism are all intertwined with mitochondria. However, a complete description of how the features of mitochondria relate to the tumor microenvironment (TME) and immunological landscape of colorectal cancer (CRC) has yet to be made. We performed subgroup analysis on CRC patient data obtained from the databases using non-negative matrix factorization (NMF) clustering. Construct a prognostic model using the mitochondrial-related gene (MRG) risk score, and then compare it to other models for accuracy. Comprehensive analyses of the risk score, in conjunction with the TME and immune landscape, were performed, and the relationship between the model and different types of cell death, radiation and chemotherapy, and drug resistance was investigated. Results from immunohistochemistry and single-cell sequencing were utilized to verify the model genes, and a drug sensitivity analysis was conducted to evaluate possible therapeutic medicines. The pan-cancer analysis is utilized to further investigate the role of genes in a wider range of malignancies.

METHODS AND RESULTS

We found that CRC patients based on MRG were divided into two groups with significant differences in survival outcomes and TME between groups. The predictive power of the risk score was further shown by building a prognostic model and testing it extensively in both internal and external cohorts. Multiple immune therapeutic responses and the expression of immunological checkpoints demonstrate that the risk score is connected to immunotherapy success. The correlation analysis of the risk score provide more ideas and guidance for prognostic models in clinical treatment.

CONCLUSION

The TME, immune cell infiltration, and responsiveness to immunotherapy in CRC were all thoroughly evaluated on the basis of MRG features. The comparative validation of multiple queues and models combined with clinical data ensures the effectiveness and clinical practicality of MRG features. Our studies help clinicians create individualized treatment programs for individuals with cancer.

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

CircAGK regulates high dihydrotestosterone-induced apoptosis in DPCs through the miR-3180-5p/BAX axis

The incidence of androgen alopecia (AGA), also known as seborrheic alopecia, has surged in recent years, and onset is occurring at younger ages. Dermal papilla cells (DPCs) are key to maintaining hair cycling, and apoptosis-driven processes in DPCs are closely related to hair follicle regeneration. Circular RNAs (circRNAs) are widely present in the human body and are closely related to the occurrence and development of many diseases. Currently, the biological functions of circRNAs in AGA are largely unknown. Whole-transcriptome sequencing was used to screen differential circRNA expression profiles between AGA patients and non-AGA patients. We found that hsa_circ_0002980 (circAGK) was significantly highly expressed in the AGA group. CircAGK promoted DPC apoptosis in the presence of high dihydrotestosterone (DHT) (15 nmol/L). By regulating the miR-3180-5p/BAX axis, circAGK promotes DPC apoptosis in a high DHT environment in vitro and inhibits hair growth in AGA mice in vivo, indicating that circAGK is a potential target for the clinical treatment of AGA.

Deciphering a mitochondria-related signature to supervise prognosis and immunotherapy in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a major public health problem in humans. The imbalance of mitochondrial function has been discovered to be closely related to the development of cancer recently. However, the role of mitochondrial-related genes in HCC remains unclear.

Methods

The RNA-sequencing profiles and patient information of 365 samples were derived from the Cancer Genome Atlas (TCGA) dataset. The mitochondria-related prognostic model was established by univariate Cox regression analysis and LASSO Cox regression analysis. We further determined the differences in immunity and drug sensitivity between low- and high-risk groups. Validation data were obtained from the International Cancer Genome Consortium (ICGC) dataset of patients with HCC. The protein and mRNA expression of six mitochondria-related genes in tissues and cell lines was verified by immunohistochemistry and qRT-PCR.

Results

The six mitochondria-related gene signature was constructed for better prognosis forecasting and immunity, based on which patients were divided into high-risk and low-risk groups. The ROC curve, nomogram, and calibration curve exhibited admirable clinical predictive performance of the model. The risk score was associated with clinicopathological characteristics and proved to be an independent prognostic factor in patients with HCC. The above results were verified in the ICGC validation cohort. Compared with normal tissues and cell lines, the protein and mRNA expression of six mitochondria-related genes was upregulated in HCC tissues and cell lines.

Conclusion

The signature could be an independent factor that supervises the immunotherapy response of HCC patients and possess vital guidance value for clinical diagnosis and treatment.

The number of mitochondrial DNA mutations as a genetic feature for hair cycle arrest (alopecia X) in Pomeranian dogs

BACKGROUND

Hair cycle arrest (HCA) is a noninflammatory alopecic disease affecting various dog breeds, particularly Pomeranian dogs. This disease is probably a hereditary disorder considering the strong breed predisposition. Despite efforts to identify the pathogenesis of this disease, an underlying specific cause is unknown.

OBJECTIVE

To identify candidate gene mutations for HCA in Pomeranian dogs.

ANIMALS

Four Pomeranian dogs diagnosed with HCA and four unaffected Pomeranian dogs.

MATERIALS AND METHODS

Whole blood was used for DNA extraction. Whole-genome sequencing (WGS) was performed, and variants were analysed using a Genome Analysis Toolkit (GATK) and SnpEff. All reads were aligned to the reference genome, Dog10K_Boxer_Tasha. Sanger sequencing was performed to define the complex mutations.

RESULTS

A total of 113 variants of mitochondrial DNA were found to be effective gene mutations in the eight dogs. The affected dogs showed significantly increased effective mutations (average 57 variants) compared with unaffected dogs (average eight variants; p < 0.05). There was no significant difference in the number of chromosomal DNA mutations between the two groups.

CONCLUSION AND CLINICAL IMPORTANCE

We suggest that an increased number of mitochondrial gene mutations are features for HCA in Pomeranian dogs.