Polymorphism of the androgen receptor gene is associated with male pattern baldness

Modelling Human Hair Follicles-Lessons from Animal Models and Beyond

The hair follicle is a specialized appendage of the skin that is critical for multiple functions, including thermoregulation, immune surveillance, and sebum production. Mammals are born with a fixed number of hair follicles that develop embryonically. Postnatally, these hair follicles undergo regenerative cycles of regression and growth that recapitulate many of the embryonic signaling pathways. Furthermore, hair cycles have a direct impact on skin regeneration in homeostasis, cutaneous wound healing, and disease conditions such as alopecia. Here, we review the current knowledge of hair follicle formation during embryonic development and the post-natal hair cycle, with an emphasis on the molecular signaling pathways underlying these processes. We then discuss efforts to capitalize on the field's understanding of in vivo mechanisms to bioengineer hair follicles or hair-bearing skin in vitro and how such models may be further improved to develop strategies for hair regeneration.

Prioritizing susceptibility genes for the prognosis of male-pattern baldness with transcriptome-wide association study

BACKGROUND

Male-pattern baldness (MPB) is the most common cause of hair loss in men. It can be categorized into three types: type 2 (T2), type 3 (T3), and type 4 (T4), with type 1 (T1) being considered normal. Although various MPB-associated genetic variants have been suggested, a comprehensive study for linking these variants to gene expression regulation has not been performed to the best of our knowledge.

RESULTS

In this study, we prioritized MPB-related tissue panels using tissue-specific enrichment analysis and utilized single-tissue panels from genotype-tissue expression version 8, as well as cross-tissue panels from context-specific genetics. Through a transcriptome-wide association study and colocalization analysis, we identified 52, 75, and 144 MPB associations for T2, T3, and T4, respectively. To assess the causality of MPB genes, we performed a conditional and joint analysis, which revealed 10, 11, and 54 putative causality genes for T2, T3, and T4, respectively. Finally, we conducted drug repositioning and identified potential drug candidates that are connected to MPB-associated genes.

CONCLUSIONS

Overall, through an integrative analysis of gene expression and genotype data, we have identified robust MPB susceptibility genes that may help uncover the underlying molecular mechanisms and the novel drug candidates that may alleviate MPB.

The Biology and Genomics of Human Hair Follicles: A Focus on Androgenetic Alopecia

Androgenetic alopecia is a highly prevalent condition mainly affecting men. This complex trait is related to aging and genetics; however, multiple other factors, for example, lifestyle, are also involved. Despite its prevalence, the underlying biology of androgenetic alopecia remains elusive, and thus advances in its treatment have been hindered. Herein, we review the functional anatomy of hair follicles and the cell signaling events that play a role in follicle cycling. We also discuss the pathology of androgenetic alopecia and the known molecular mechanisms underlying this condition. Additionally, we describe studies comparing the transcriptional differences in hair follicles between balding and non-balding scalp regions. Given the genetic contribution, we also discuss the most significant risk variants found to be associated with androgenetic alopecia. A more comprehensive understanding of this pathology may be generated through using multi-omics approaches.

Uncovering the genetic architecture and evolutionary roots of androgenetic alopecia in African men

Androgenetic alopecia is a highly heritable trait. However, much of our understanding about the genetics of male pattern baldness comes from individuals of European descent. Here, we examined a novel dataset comprising 2,136 men from Ghana, Nigeria, Senegal, and South Africa that were genotyped using a custom array. We first tested how genetic predictions of baldness generalize from Europe to Africa, finding that polygenic scores from European GWAS yielded AUC statistics that ranged from 0.513 to 0.546, indicating that genetic predictions of baldness in African populations performed notably worse than in European populations. Subsequently, we conducted the first African GWAS of androgenetic alopecia, focusing on self-reported baldness patterns at age 45. After correcting for present age, population structure, and study site, we identified 266 moderately significant associations, 51 of which were independent (p-value < 10-5, r2 < 0.2). Most baldness associations were autosomal, and the X chromosomes does not appear to have a large impact on baldness in African men. Finally, we examined the evolutionary causes of continental differences in genetic architecture. Although Neanderthal alleles have previously been associated with skin and hair phenotypes, we did not find evidence that European-ascertained baldness hits were enriched for signatures of ancient introgression. Most loci that are associated with androgenetic alopecia are evolving neutrally. However, multiple baldness-associated SNPs near the EDA2R and AR genes have large allele frequency differences between continents. Collectively, our findings illustrate how evolutionary history contributes to the limited portability of genetic predictions across ancestries.

mRNA Levels of Aromatase, 5α-Reductase Isozymes, and Prostate Cancer-Related Genes in Plucked Hair from Young Men with Androgenic Alopecia

Androgenic alopecia (AGA) is the most prevalent type of progressive hair loss and has psychological repercussions. Nevertheless, the effectiveness of current pharmacological treatments remains limited, in part because the molecular basis of the disease has not been fully elucidated. Our group previously highlighted the important roles of aromatase and 5α-reductase (5α-R) in alopecia in young women with female pattern hair loss. Additionally, an association has been proposed between AGA and prostate cancer (PCa), suggesting that genes implicated in PCa would also be involved in AGA. A low-invasive, sensitive, and precise method was used to determine mRNA levels of aromatase, 5α-R isozymes, and 84 PCa-related genes in samples of plucked hair from young men with AGA and controls. Samples were obtained with a trichogram from the vertex scalp, and mRNA levels were quantified using real-time RT-PCR. The men with AGA had significantly higher 5α-R2 mRNA levels in comparison to controls; interestingly, some of them also showed markedly elevated mRNA levels of 5α-R1 or 5α-R3 or of both, which may explain the varied response to 5α-R inhibitor treatments. The men with AGA also showed significant changes versus controls in 6 out of the 84 genes implicated in PCa. This study contributes greater knowledge of the molecular bases of AGA, facilitating early selection of the most appropriate pharmacological therapy and opening the way to novel treatments.

Androgenetic alopecia: An update

Androgenetic alopecia (AGA) is the most common nonscarring alopecia and is characterised by distinct gradual patterned hair loss. AGA is mediated by genetic predisposition and excessive follicular sensitivity to androgens, mainly in males, leading to the progressive conversion of scalp terminal hair into vellus hair. Although highly prevalent, it is not fatal but may have a severe psychosocial impact, especially on females and younger males. Significant advances have been made in understanding AGA's epidemiology and pathophysiology, but only 2 drugs remain approved by the FDA - finasteride and minoxidil. Prolonged use of these drugs, is a prerequisite for enhanced treatment response. However, this leads to poor medication adherence and adverse effects from extended use eg, the "postfinasteride syndrome" which persists beyond stopping the drug. Hence, there is a need for research on more effective alternative treatments for AGA, with fewer side effects. This paper reviewed recent advances in AGA pathophysiology and its treatment options. The recently characterized structure of type 2, 5-alpha reductase holds significance in comprehending present and prospective treatments of AGA.

A point-of-care platform for hair loss-related single nucleotide polymorphism genotyping

Rapid genotyping of single nucleotide polymorphism (SNP) is crucial for prognostics and disease management, enabling more rapid therapy selection and treatment determination. Here, we introduce a point-of-care platform for hair loss-related SNP genotyping based on allele-specific loop-mediated isothermal amplification (AS-LAMP) combined with naked-eye visualization. The specificity of the AS-LAMP assay was significantly enhanced by using mismatched allele-specific primers. AS-LAMP reaction and Schiff's reagent-based colorimetric detection were successfully performed using a thermoplastic genotyping chip. This strategy also showed potential for determining homozygotes and heterozygotes in a target sample. To assess SNP genotyping capacity, the genotyping chip was fabricated to visually detect rs6152 polymorphism of an androgen receptor gene associated with genetically induced hair loss. The genotyping platform rapidly identified the SNP within 40 min, and the detection limit was as low as 1 pg/μL of the target DNA contained in human serum. The introduced strategy showed high specificity and stability in discriminating low-abundance mutations, making it suitable as a portable and affordable point-of-care platform for rapid and accurate SNP discrimination applicable for bedside detection.

Association between androgenetic alopecia and periodontitis

AIM

Androgenic alopecia (AGA) is men's most common form of hair loss. It is affected by changes in the expression and activity of 5αR and the metabolism of testosterone and DHT. There is an association between AGA and systemic inflammatory diseases. We hypothesized that there is an association between AGA and periodontal disease, as inflamed gingiva and periodontal fibroblasts have been shown to express more 5αR. Thus, this study aimed to evaluate the relationship between periodontal disease and AGA and the potential effect of aging on this association.

MATERIALS AND METHODS

Out of a cohort of 1088 individuals, 385 white males aged 25-65 with similar socioeconomic levels and without systemic disease were included. Periodontitis was defined using NHANES data. AGA was evaluated using the Norwood-Hamilton scale. The relationship between AGA, periodontal disease severity, and age was assessed.

RESULTS

There was a correlation between age and baldness (r = .421, p < .001). There was a significant correlation between AGA and periodontal disease in younger patients aged 25-34 and 35-44. (p < .042 and p < .036, respectively). There was no significant correlation between AGA and periodontal disease in the 45-54 and 55-65 age groups (p > .05).

CONCLUSION

There may be a relationship between periodontal disease and AGA in the 25-44 age range, suggesting that this association starts at an early age in adulthood.

Male-pattern hair loss: Comprehensive identification of the associated genes as a basis for understanding pathophysiology

Male-pattern hair loss (MPHL) is a highly heritable and prevalent condition that is characterized by progressive hair loss from the frontotemporal and vertex scalp. This androgen-dependent hair loss may commence during puberty, and up to 80 % of European men experience some degree of MPHL during their lifetime. Current treatment options for MPHL have limited efficacy, and improved understanding of the underlying biological causes is required to facilitate novel therapeutic approaches. To date, molecular genetic studies have identified 389 associated genomic regions, have implicated numerous genes in these regions, and suggested pathways that are likely to contribute to key pathophysiological mechanisms in MPHL. This review provides an overview of the current status of MPHL genetic research. We discuss the most significant achievements, current challenges, and anticipated developments in the field, as well as their potential to advance our understanding of hair (loss) biology, and to improve hair loss prediction and treatment.

Are finasteride-related penile curvature/Peyronie's disease Adverse Event Reports worthy of further clinical investigation? Disproportionality analysis based on both the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) pharmacovigilance databases

A limited number of studies have described patients on finasteride showing findings which were consistent with Peyronie's disease (PD). We aimed to detect a pharmacovigilance signal of possible association between finasteride and PD-related clinical features. The Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database was queried to identify the ten drugs which were associated the most with the adverse drug reactions (ADRs) recorded as "penile curvature" and/or "Peyronie's disease". A similar analysis, including the same drugs, was carried out for the EMA (European Medicines Agency) EudraVigilance (EV) database. Descriptive data have been analyzed, and Proportional Reporting Ratios (PRRs) have been computed against the other nine drugs of the database. Overall, 860 reports of "penile curvature" and/or "Peyronie's disease", were identified in the FAERS database, 214 of which (24.9%) were associated with finasteride. Most reports (56.9%) were submitted by healthcare professionals. Where a treatment-indication was stated, the vast majority of reports (176/210; 83.8%) were associated with androgenetic alopecia. The outcome of most ADRs was "serious" (82.2%), with 96 ADRs resulting in levels of permanent disability. For 97/214 individual cases, penile curvature/PD reports were not part of a syndromic cluster suggestive of post-finasteride syndrome (PFS). The PRR resulted 6.6 (95% CI: 5.6-7.8) and 11.8 (95% CI: 9.08-15.33), respectively, in the FAERS and in the EV databases. Notwithstanding the related limitations and biasing factors of pharmacovigilance studies based on spontaneous reporting, the PRR values here identified should be interpreted as strong signals of disproportionality. These findings, per se, are however not useful to confirm any causal association. Clinical studies are needed to investigate on the possible role for finasteride in causing PD-related clinical features, an hypothesis which remains highly speculative due to the very questionable quality of present data.

Weekly treatment with SAMiRNA targeting the androgen receptor ameliorates androgenetic alopecia

Androgenetic alopecia (AGA) is the most common type of hair loss in men and women. Dihydrotestosterone (DHT) and androgen receptor (AR) levels are increased in patients with AGA, and DHT-AR signaling correlates strongly with AGA pathogenesis. In this study, treatment with self-assembled micelle inhibitory RNA (SAMiRNA) nanoparticle-type siRNA selectively suppressed AR expression in vitro. Clinical studies with application of SAMiRNA to the scalp and massaging to deliver it to the hair follicle confirmed its efficacy in AGA. For identification of a potent SAMiRNA for AR silencing, 547 SAMiRNA candidates were synthesized and screened. SAMiRNA-AR68 (AR68) was the most potent and could be efficiently delivered to human follicle dermal papilla cells (HFDPCs) and hair follicles, and this treatment decreased the AR mRNA and protein levels. We confirmed that 10 µM AR68 elicits no innate immune response in human PBMCs and no cytotoxicity up to 20 µM with HFDP and HaCaT cells. Clinical studies were performed in a randomized and double-blind manner with two different doses and frequencies. In the low-dose (0.5 mg/ml) clinical study, AR68 was applied three times per week for 24 weeks, and through quantitative analysis using a phototrichogram, we confirmed increases in total hair counts. In the 24-week long high-dose (5 mg/ml) clinical study, AR68 showed average additional hair growth of 1.3-1.9 hairs/cm² per month, which is comparable to finasteride. No side effects were observed. Therefore, SAMiRNA targeting AR mRNA is a potential novel topical treatment for AGA.

Understanding Pattern Hair Loss-Hair Biology Impacted by Genes, Androgens, Prostaglandins and Epigenetic Factors

Pattern hair loss (PHL) is the most frequent cause of hair loss in men and women, accounting for 65% of consultations in a hair referral center. PHL is understood to represent a hereditary, age-dependent progressive thinning of the scalp hair, which follows distinct clinical patterns with notable differences depending on sex and age of onset. Clinical and investigative advances have helped us to understand some of the pathogenic steps, leading to PHL. Besides genetic factors and peculiarities of androgen metabolism, additional pathogenic factors that are suspected include microbiomata, oxidative stress, and microinflammation. While further suspects are likely to be exposed, individual diversity of causal agents, as well as of the sequence of events, or combined factors, must be kept in mind. A large number of therapeutic molecules claimed to be active and patented in this field, and their limited efficacy in offering a definitive cure of PHL confirm the complexity of PHL. The aim of therapy is to retard progression of hair thinning and increase hair coverage of the scalp. As yet, two FDA-approved drugs are available for this purpose, oral finasteride, and topical solution of minoxidil. Variations in posology and formulation allow for an enhancement of patient comfort and treatment efficacy. Antiandrogen treatments in women with normal androgen levels have questionable efficacy while having health risks.

Androgenetic alopecia and COVID-19: Is there a clinical connection?

BACKGROUND

During the coronavirus disease 2019 (COVID-19) outbreak, multiple studies showed higher rates of severe infection in adults and specifically in male patients, which may be related to differences in androgen receptor (AR) expression. Androgenetic alopecia (AGA) is one of the AR expression manifestations.

AIM

To explore AGA severity as a possible risk factor for COVID-19 severity in hospitalized patients.

METHODS

A total of 164 subjects (116 men and 48 females) with confirmed COVID-19 in need of hospitalization were included in this study. An experienced dermatologist examined the correlation of clinical signs of COVID-19 severity with AGA types. For evaluation of the association between categorical variables and comparison of the mean age in three groups of COVID-19 patients, the Fisher's exact test and the analysis of variance were used.

RESULTS

Our cross-sectional study included 116 male patients (70.7%) with a median age of 65.5 (age range: 22-97) years. Among them, 13.8% required intubation, 15.5% needed intensive care unit (ICU) care, and 70.7% required inward hospitalization. The Hamilton-Norwood Scale (HNS) was as follows: HNS I 14.7%, HNS II 12.1%, HNS III 20.7%, HNS IV 19.8%, HNS IV 29.8%, HNS V 17.2%, HNS VI 13.8%, and HNS VII 1.7%. Also, 29.3% of the patients were female, possessing a median age of 72 (age range: 23-98) years. In this group, 8.3% required intubation, 6.3% required ICU care, and 85.4% needed inpatient ward admission care. The Ludwig Scale (LS) was as follows: LS I 52.1%, LS II 35.4%, and LS III 12.5%.

CONCLUSION

The severity of AGA type did not correlate with the severity of COVID-19 among hospitalized patients. Our results were in contrast with other research that suggested AGA severity as a marker of unfavorable outcomes of COVID-19.

Impaired metabolic effects of metformin in men with early-onset androgenic alopecia

Background

Early-onset androgenic alopecia is considered the phenotypic equivalent of polycystic ovary syndrome in men. The purpose of the current study was to investigate whether the presence of early-onset male-pattern baldness modulates metabolic effects of metformin.

Methods

This prospective case–control study included 2 groups of men at high risk for type 2 diabetes: 72 individuals with androgenic alopecia (group A) and 75 subjects with normal hair growth (group B). Both groups were matched for age, blood pressure, body mass index, insulin sensitivity and plasma lipids. Glycated hemoglobin, glucose, plasma lipids, indices of insulin sensitivity/resistance, sex hormones, high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D were determined before and after metformin treatment (1.7 g daily).

Results

Twelve-month metformin treatment reduced fat content, waist circumference, glycated hemoglobin, glucose and triglycerides, as well as improved insulin sensitivity. Although observed in both study populations, these effects were more pronounced in group B. Moreover, metformin decreased hsCRP and bioavailable testosterone levels in group B, as well as reduced 25-hydroxyvitamin D concentration in group A. Treatment-induced changes in glucose homeostasis markers correlated with the impact of metformin on hsCRP and 25-hydroxyvitamin D levels.

Conclusions

Metabolic effects of metformin in males are attenuated if they have coexisting early-onset androgenic alopecia. This finding may be partially explained by differences in severity of low-grade systemic inflammation and vitamin D status. The obtained results, requiring confirmation in large prospective studies, suggest that men with early-onset male-pattern baldness benefit to a lesser degree from metformin treatment than other men at high risk for type 2 diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43440-021-00347-8.

Perspectives on miRNAs Targeting DKK1 for Developing Hair Regeneration Therapy

Androgenetic alopecia (AGA) remains an unsolved problem for the well-being of humankind, although multiple important involvements in hair growth have been discovered. Up until now, there is no ideal therapy in clinical practice in terms of efficacy and safety. Ultimately, there is a strong need for developing a feasible remedy for preventing and treating AGA. The Wnt/β-catenin signaling pathway is critical in hair restoration. Thus, AGA treatment via modulating this pathway is rational, although challenging. Dickkopf-related protein 1 (DKK1) is distinctly identified as an inhibitor of canonical Wnt/β-catenin signaling. Thus, in order to stimulate the Wnt/β-catenin signaling pathway, inhibition of DKK1 is greatly demanding. Studying DKK1-targeting microRNAs (miRNAs) involved in the Wnt/β-catenin signaling pathway may lay the groundwork for the promotion of hair growth. Bearing in mind that DKK1 inhibition in the balding scalp of AGA certainly makes sense, this review sheds light on the perspectives of miRNA-mediated hair growth for treating AGA via regulating DKK1 and, eventually, modulating Wnt/β-catenin signaling. Consequently, certain miRNAs regulating the Wnt/β-catenin signaling pathway via DKK1 inhibition might represent attractive candidates for further studies focusing on promoting hair growth and AGA therapy.

Insights into disparities observed with COVID-19

The onset of human disease by infection with SARS-CoV-2 causing COVID-19 has revealed risk factors for disease severity. There are four identified factors that put one at high risk for infection and/or mortality creating a disparity: age, co-morbidities, race/ethnicity and gender. Data indicate that the older a person is, and/or the presence of obesity and diabetes, cardiovascular disease and chronic kidney disease place one at higher risk for COVID-19. In the United States, specific race/ethnicities, particularly African Americans and Native Americans, are strong COVID-19 risk components. Male gender has also emerged as a severity risk factor. For age and racial/ethnicities, the accumulation of health co-morbidities is common precipitating mechanisms. In particular, underlying socio-economic structures in the United States likely drive development of co-morbidities, putting affected populations at higher risk for severe COVID-19. Sudden cardiac death triggered by a common sodium channel variant in African Americans with COVID-19 has not been evaluated as a cause for racial disparity. There is no evidence that racial/ethnic differences for COVID-19 are caused by ABO blood groups, use of angiotensin-converting enzyme (ACE) inhibitors or from amino acid substitutions in the SARS-CoV-2 spike protein. There is growing evidence that androgen-enabled expression of ACE2 receptors and the serine protease TMPRSS2, two permissive elements engaging the SARS-CoV-2 spike protein for infection, may contribute to severe COVID-19 in men. Overall, COVID-19 has generated disparities for who is infected and the severity of that infection. Understanding the mechanisms for the disparity will help nullify the differences in risk for COVID-19.

Investigating the Safety and Efficacy of Platelet-Rich Plasma (PRP) Treatment for Female Androgenetic Alopecia: Review of the Literature

Background: female androgenetic alopecia (FAGA) is a common cause of non-scarring alopecia in women, affecting approximately 40% of women by age 50, bearing a significant psychosocial burden on affected patients. Platelet-rich plasma (PRP) has been widely investigated as a potential effective treatment for several dermatological conditions, including male androgenetic alopecia (MAGA). However, few studies have been conducted focusing on the use of PRP in FAGA. The aim of this review was to identify reports that investigated the use of PRP for the treatment of FAGA. Methods: Electronic databases of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) from inception to September 2020 have been searched using different combinations of the following terms: “androgenetic alopecia,” “FAGA,” “female pattern hair loss,” “platelet-rich fibrin,” “platelet-rich plasma,” and “PRP”. Results and conclusions: Eight (n = 8) clinical studies consistent with our research were identified. A total of 197 subjects has been enrolled in the included studies. All of them were adult female patients (mean age: 38.9) affected by female pattern hair loss. PRP is a well-tolerated procedure which showed promising results in males-only and mixed populations of AGA patients. PRP showed to produce high levels of satisfaction and improvement in the quality of life in patients affected by FAGA. In the light of this evidence, PRP may be proposed in patients who did not respond or did not tolerate topical minoxidil, as well as in combination with topical and oral treatments.

Therapeutic implications of topical cetirizine 1% in treatment of male androgenetic alopecia: A case-controlled study

BACKGROUND

Androgenetic alopecia (AGA) is the most common form of alopecia in men. Cetirizine, a second-generation H1 blocker, is known for its anti-inflammatory properties and its ability to decrease prostaglandin D2 (PGD2) production.

AIM

To evaluate the efficacy and tolerability of topical cetirizine in male patients with AGA.

METHODS

Two groups of 30 patients each (healthy males aged between 22 and 55 years) with different grades of AGA classified according to the Hamilton-Norwood classification were recruited for this study. Group A subjects applied 1 mL of 1% topical cetirizine daily, while group B subjects served as controls and were instructed to apply 1 mL of a placebo solution for 6 months.

RESULTS

Dermoscopic assessment revealed significantly higher hair regrowth among the cetirizine-treated group (P < .001). The patients' satisfaction was significantly higher among the cetirizine-treated group (P < .001).

CONCLUSION

The current study highlights a potential role cetirizine might have in treating AGA. It should be noted that studies are lacking in this regard and more randomized and controlled trials are warranted in order to confirm or refute such early findings.

Determination of Intraprostatic and Intratesticular Androgens

Androgens represent the main hormones responsible for maintaining hormonal balance and function in the prostate and testis. As they are involved in prostate and testicular carcinogenesis, more detailed information of their active concentration at the site of action is required. Since the introduction of the term intracrinology as the local formation of active steroid hormones from inactive precursors of the adrenal gland, mainly dehydroepiandrosterone (DHEA) and DHEA-S, it is evident that blood circulating levels of sex steroid hormones need not reflect their actual concentrations in the tissue. Here, we review and critically evaluate available methods for the analysis of human intraprostatic and intratesticular steroid concentrations. Since analytical approaches have much in common in both tissues, we discuss them together. Preanalytical steps, including various techniques for separation of the analytes, are compared, followed by the end-point measurement. Advantages and disadvantages of chromatography-mass spectrometry (LC-MS, GC-MS), immunoanalytical methods (IA), and hybrid (LC-IA) are discussed. Finally, the clinical information value of the determined steroid hormones is evaluated concerning differentiating between patients with cancer or benign hyperplasia and between patients with different degrees of infertility. Adrenal-derived 11-oxygenated androgens are mentioned as perspective prognostic markers for these purposes.

The Double Edge Sword of Testosterone's Role in the COVID-19 Pandemic

COVID-19 is a complex disease with a multifaceted set of disturbances involving several mechanisms of health and disease in the human body. Sex hormones, estrogen, and testosterone, seem to play a major role in its pathogenesis, development, spread, severity, and mortalities. Examination of factors such as age, gender, ethnic background, genetic prevalence, and existing co-morbidities, may disclose the mechanisms underlying SARS-CoV-2 infection, morbidity, and mortality, paving the way for COVID-19 amelioration and substantial flattening of the infection curve. In this mini-review, we focus on the role of testosterone through a discussion of the intricate mechanisms of disease development and deterioration. Accumulated evidence suggests that there are links between high level (normal male level) as well as low level (age-related hypogonadism) testosterone in disease progression and expansion, supporting its role as a double-edged sword. Unresolved questions point to the essential need for further targeted studies to substantiate these contrasting mechanisms.

Shedding light on therapeutics in alopecia and their relevance to COVID-19

As of July 9, 2020, there were more than 12 million confirmed cases of coronavirus disease 2019 (COVID-19) across the globe, with more than 550,000 deaths. Many European countries, including Belgium, the United Kingdom, Italy, and Spain, have had the highest numbers of fatalities per capita. This indicates the potential for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus to overwhelm even the most advanced health care systems despite extreme societal interventions. Since its emergence, SARS-CoV-2 has disseminated across the globe, affecting the structure of global societies, infrastructure, and economies. Patients with alopecia are a diverse group who, for various indications, are prescribed a number of antimicrobials and antiandrogen treatments in addition to immunomodulatory therapies such as hydroxychloroquine, oral corticosteroids, and a range of broad immunosuppressants. These drugs are being scrutinized for their capacity to potentially affect SARS-CoV-2 outcomes. We examine these treatments and highlight the critical role that patient registries will play in generating real-world evidence to assess their impact on COVID-19 outcomes.

Ectodysplasin-A2 induces dickkopf 1 expression in human balding dermal papilla cells overexpressing the ectodysplasin A2 receptor

Androgenetic alopecia (AGA) is a common genetic disorder, and a X-chromosomal locus that contains the androgen receptor (AR) and ectodysplasin A2 receptor (EDA2R) genes represents a major susceptibility locus for AGA. In our previous study, we reported that ectodysplasin-A2 (EDA-A2) induces apoptosis in cultured human hair follicle (HF) cells and promotes the regression of HFs in mice. However, the role of the EDA-A2/EDA2R in AGA remains unknown, as the causative gene in this pathway has not yet been identified and potential functional connections between EDA-A2 signaling and the androgen pathway remain unclear. In this study, we investigated the expression of EDA2R in balding HFs and matched with non-balding HFs. The EDA2R level was upregulated in the balding dermal papilla (DP) cells compared with non-balding DP cells derived from patients with AGA. However, EDA2R was strongly expressed in both balding and non-balding outer root sheath (ORS) cells. We screened EDA-A2-regulated genes in balding DP cells and identified dickkopf 1 (DKK-1) as catagen inducer during the hair cycle. The mRNA and protein expression levels of DKK-1 were both upregulated by EDA-A2. In addition, DKK-1 expression was induced by EDA-A2 both in cultured human HFs and in mouse HFs. Moreover, the EDA-A2-induced apoptosis of DP and ORS cells was reversed by the antibody-mediated neutralization of DKK-1. Collectively, our data strongly suggest that EDA-A2 induces DKK-1 secretion and causes apoptosis in HFs by binding EDA2R, which is overexpressed in the bald scalp. EDA-A2/EDA2R signaling could inhibit hair growth through DKK-1 induction, and an inhibitor of EDA-A2/EDA2R signaling may be a promising agent for the treatment and prevention of AGA.

Hormonal regulation in male androgenetic alopecia-Sex hormones and beyond: Evidence from recent genetic studies

Male-pattern hair loss, also termed androgenetic alopecia (AGA), is a highly prevalent age-related condition that is characterized by a distinct pattern of hair loss from the frontotemporal and vertex regions of the scalp. The phenotype is highly heritable and hormone dependent, with androgens being the recognized critical hormonal factor. Numerous molecular genetic studies have focused on genetic variation in and around the gene that encodes the androgen receptor. More recently, however, the availability of high-throughput molecular genetic methods, novel methods of data analysis and sufficiently large sample sizes have rendered possible the systematic investigation of the contribution of other components of the androgen receptor pathway or hormonal pathways beyond the androgen receptor signalling pathways. Over the past decade, genome-wide association studies of increasingly large cohorts have enabled the genome-wide identification of genetic risk factors for AGA, and yielded unprecedented insights into the underlying pathobiology. The present review discusses some of the most intriguing genetic findings on the relevance of (sex)hormonal signalling in AGA.

CAG Repeats in the androgen receptor gene is associated with oligozoospermia and teratozoospermia in infertile men in Jordan

CAG trinucleotide repeats are coded for the polyglutamine tract in the N-terminal of the androgen receptor (AR) gene which varies in normal individuals from 6 to 36 residues. In this study, we inspected the impact of the CAG repeats on the spermatogenic defects by measuring the size of AR-CAG repeats length in a cohort of 260infertile and 169 fertile Jordanian men. The infertile group included three subgroups of a zoospermic, oligozoospermic and teratozoospermia men. The CAG allele size was determined by direct sequencing. The results showed a significant association between the length of the AR-CAG repeats and men's infertility (p = .001). In particular, the current cohort demonstrated a significant association between the AR-CAG length polymorphism and oligozoospermia (p < .001) and teratozoospermia (p < .001) but not azoospermia. According to distributions of allele frequency, the risk of oligozoospermia was 5.5-fold greater than normal when alleles frequency > 20 repeats, while the risk of teratozoospermia was > 10.6 folds greater than normal when allele frequency > 22 repeats. In conclusion, our results underscored that the long repeats of the AR-CAG polymorphism within the normal range might be associated with abnormal spermatogenesis such as teratozoospermia and oligozoospermia and contributing to infertility in Jordanian men.

Physiology and Medical Treatments for Alopecia

Androgenetic alopecia (AGA) is the most common hair loss disorder in men and women. The characteristic and reproducible balding pattern in AGA negatively affects self-image and the external perceptions of the balding patient. The phenotypical changes are driven by dihydrotestosterone (DHT) and its precursor testosterone. DHT induces follicle miniaturization and hair cycle changes until resulting hairs no longer extrude through the skin surface. AGA is inherited in a polygenetic pattern and is susceptible to epigenetic and environmental factors. Currently, minoxidil, finasteride, and photolaser therapy are the only Food and Drug Administration-approved medical treatments for AGA.

A review of the treatment of male pattern hair loss

Introduction: Androgenetic alopecia is a common hair loss disorder affecting up to 80% of males by the age of 80. It is characterized by androgen related progressive thinning of hair in a defined pattern. It results in diminished self-esteem, reduced confidence and distress in affected men, irrespective of age or stage of baldness. An effective treatment for hair baldness is needed.Areas covered: In androgenetic alopecia, hair follicles undergo progressive miniaturization. Genetic factors and androgens are key role-players in disease pathogenesis. Herein the authors review the pharmacologic treatment of androgenetic alopecia, which involves 5 alpha reductase inhibitors, minoxidil and prostaglandins. Non-pharmacologic approaches are also explored.Expert opinion: Androgenetic alopecia progresses over time and although the current available medical treatments like finasteride and minoxidil are effective in arresting the progression of the disease, they allow only partial regrowth of hair at its best. Early treatment achieves a more optimal outcome. Non-pharmacologic treatments like PRP can be considered in patients refractory to medical treatment.Abbreviations: MPHL: male pattern hair loss; AGA: androgenetic alopecia; DHT: dihydrotestosterone; 5AR: 5-alpha-reductase; VEGF: vascular endothelial growth factor; PG's: prostaglandins (PG's); PGD2R: prostaglandin D2 receptor; VPA: valproic aid; SR: Serenoa Repens; PRP: platelet-rich plasma; PDGF: platelet derived growth factor; TGF: transforming growth factor; ERK: extracellular signal-regulated kinase; PKB: protein kinase B; LLLT: low-level laser therapy; ROS: reactive oxygen species; RCT: randomized control trial; SFRP1: secreted frizzled related protein 1; DP: dermal papilla; PDE5: phosphodiesterase 5.

Androgenetic Alopecia: Relationship to Anthropometric Indices, Blood Pressure and Life-Style Habits

Purpose

The association of androgenetic alopecia (AGA) with cardiovascular risk factors including hypertension, smoking and high body mass index (BMI) has been investigated in several studies. However, the results are discrepant. The aim of the present study was to evaluate the association of AGA with anthropometrics, blood pressure and lifestyle habits.

Patients and Methods

In this case-control study, 256 men with AGA and 256 age-matched healthy controls were evaluated. Systolic and diastolic blood pressures, as well as anthropometric indices were measured. Data on lifestyle habits including smoking, hookah use and alcohol consumption were also collected.

Results

Patients with AGA had significantly lower BMI and lower waist to hip ratio as compared to controls (p = 0.012 and p = 0.002, respectively). Other anthropometrics as well as mean systolic and diastolic blood pressures were not significantly different between the two groups. There was no significant difference between patients and controls in terms of lifestyle habits. Patients with severe AGA (Norwood-Hamilton classification type IV-VII) had significantly higher systolic and diastolic blood pressures as compared to those with mild to moderate AGA (Norwood-Hamilton classification type II, III), but the mean age of the former group was also significantly higher (p < 0.001).

Conclusion

In contrast to some previous studies, our findings did not show a significant association between certain cardiovascular risk factors (such as hypertension and smoking) and AGA. Although lower BMI and lower waist to hip ratio were observed in the patient group, these values were within normal limits and therefore not biologically significant.

The effect of GGC and CAG repeat polymorphisms on the androgen receptor gene in response to finasteride therapy in men with androgenetic alopecia

Background:

It should be assessed whether the polymorphisms on androgen receptor gene can affect therapeutic response to androgenetic alopecia (AGA) medications. We aimed to find a link between polymorphisms on the androgen receptor gene (including the number of triple sequences of cytosine, adenine, and guanine [CAG] and guanine-guanine-cytosine [GGC]) and response to treatment with finasteride in male patients.

Materials and Methods:

This case–control study was performed on 25 consecutive male patients with hereditary AGA and 25 sex-matched healthy individuals without AGA. The complete sequence of the gene was extracted from the NCBI database. To replicate the samples, real-time polymerase chain reaction technique was used for the pointed gene and the results were confirmed by the sequencing technique.

Results:

The mean number of CAG sequences in two groups with and without baldness, was 23.16 ± 0.47 and 23.04 ± 0.67. For GGC sequencing with and without baldness, mean count was 22.22 ± 1.45 and 19.92 ± 81.2, respectively, which was significantly higher in the group with baldness. There was no association between number of CAG sequence and improvement in hair loss or the level of patients' satisfaction, but lower number of GGC sequences was associated with higher rate of stopping hair loss, more new hair growth, higher level of satisfaction, and more clinical response to finasteride and clinical improvement in AGA patients.

Conclusion:

Counting of GGC sequence in the gene encoding the androgen receptor is associated with an increase in odds of baldness and a decrease in the response rate to finasteride in AGA patients.

Identification of two additional novel mutations in the AR gene associated with severe forms of androgen insensitivity syndrome

The Androgen insensitivity syndrome (AIS) in its complete form (CAIS) is a disorder in abnormal male development characterized by a complete female phenotype in a 46,XY individual. The most frequent cause of this disorder is a hemizygous mutation in androgen receptor (AR) gene located in X chromosome. The first aim of this study was to confirm the clinical diagnosis in a series of Tunisian patients with a typical phenotype of CAIS by molecular genetic analysis. The second aim was to determine the AR mutational profile in the local population. The entire coding region and the exon-intron junctions of the AR gene were sequenced in a series of ten patients. AR defects were found in nine patients. Despite the small number of cases, two of the nine identified mutations were novel. The first novel mutation was an 8-bp deletion in exon 1 (c.862_869del) resulting in a frameshift (p.A288Qfs*14). The second was a splice site mutation c.1885 + 1G > T (IVS3 + 1G > T). In this study, genetic testing has confirmed the diagnosis of most CAIS patients and has revealed two novel mechanisms responsible for the pathogenesis of AIS, as well as seven other reported mutations.

Monofilament threads in treatment of female hair loss

BACKGROUND

Recently, thread treatment has been commonly used in Korean medicine for cosmetic reasons such as decreasing skin wrinkles. It was noted that an inserted thread caused constant stimulation, followed by assistance for connective tissue regeneration. However, its role in hair development has not yet been revealed.

OBJECTIVE

To perform a pilot study on the effect of monofilament threads scalp injections in women with female androgenetic alopecia.

MATERIALS AND METHODS

This double-blind, multicenter, placebo-controlled study compared the effect of monofilament threads with that of saline as placebo. The endpoints were hair count and hair mass index (HMI), along with patient-opinion survey responses.

RESULTS

HMI or hair count has statistically significantly differed between the study and placebo groups. However, 73.3% of the treatment subjects (vs. 0% of the placebo subjects) experienced substantial improvement in hair loss, rate of hair loss, hair thickness, and ease of managing/styling hair, and 76.8% (vs. 18.4% of the placebo group) reported that their hair felt coarser or heavier after the treatment.

CONCLUSION

Monofilament threads demonstrate highly statistically significant improvement in HMI or hair count in women female pattern hair loss. The patient survey results suggest a therapeutic advantage of monofilament threads as perceived by patients and according to hair count or HMI.

Genetic variations associated with response to dutasteride in the treatment of male subjects with androgenetic alopecia

Dutasteride, a dual inhibitor of both type I and II 5α-reductases, is used to treat male pattern hair loss (MPHL). However, patient response to dutasteride varies in each individual, the cause of which is yet to be identified. To identify genetic variants associated with response to dutasteride treatment for MPHL, a total of 42 men with moderate MPHL who had been treated with dutasteride for 6 months were genotyped and analysed by quantitative linear regression, case-control association tests, and Fisher’s exact test. The synonymous single nucleotide polymorphism (SNP) rs72623193 in DHRS9 was most significantly associated with response to dutasteride, followed by the non-synonymous SNP rs2241057 in CYP26B1. Additionally, variants in ESR1, SRD5A1, CYP19A1, and RXRG are suggested to be associated with response to dutasteride. Cumulative effect and interaction among these SNPs were presented in both additive and non-additive models.

Photobiomodulation for the management of alopecia: mechanisms of action, patient selection and perspectives

Photobiomodulation (PBM) or low-level laser therapy was discovered over 50 years ago, when Mester in Hungary observed regrowth of hair in mice when irradiated with a ruby laser. At the present time, several different PBM devices are marketed to assist with hair regrowth in alopecia patients. This review covers the three main types of alopecia (androgenetic, areata, and chemotherapy-induced), and discusses the mechanism of action of PBM for each disease. The different devices used (mostly low powered red laser diodes), dosimetry, animal models, and clinical trials are summarized. Criteria for patient selection are outlined. Finally a perspectives section looks forward to the future.

The diagnosis of androgenetic alopecia in children: Considerations of pathophysiological plausibility

Androgenetic alopecia (AGA), one of the most common causes of hair loss in men and women, is an infrequent cause of alopecia in children. In AGA, patients generally start noticing hair thinning after the onset of puberty due to progressive miniaturisation of the hair follicle which leads to vellus transformation of terminal hair. However, the occurrence of prepubertal AGA has rarely been reported in the literature. The pathophysiology of AGA is tightly linked to androgen hormones; prepubertal children do not usually produce significant amounts of adrenal or gonadal androgens. When it does occur, an underlying abnormality should be suspected. Secondary causes of AGA must be excluded when evaluating a patient before the appearance of puberty. Premature puberty, polycystic ovarian syndrome and other causes of hyperandrogenism can present with hair loss in an androgenetic pattern. This article reviews the normal physiology of androgen hormones and their role in the pathophysiology of childhood AGA.

Dissection of genetic variation and evidence for pleiotropy in male pattern baldness

Male pattern baldness (MPB) is a sex-limited, age-related, complex trait. We study MPB genetics in 205,327 European males from the UK Biobank. Here we show that MPB is strongly heritable and polygenic, with pedigree-heritability of 0.62 (SE = 0.03) estimated from close relatives, and SNP-heritability of 0.39 (SE = 0.01) from conventionally-unrelated males. We detect 624 near-independent genome-wide loci, contributing SNP-heritability of 0.25 (SE = 0.01), of which 26 X-chromosome loci explain 11.6%. Autosomal genetic variance is enriched for common variants and regions of lower linkage disequilibrium. We identify plausible genetic correlations between MPB and multiple sex-limited markers of earlier puberty, increased bone mineral density (r_g = 0.15) and pancreatic β-cell function (r_g = 0.12). Correlations with reproductive traits imply an effect on fitness, consistent with an estimated linear selection gradient of -0.018 per MPB standard deviation. Overall, we provide genetic insights into MPB: a phenotype of interest in its own right, with value as a model sex-limited, complex trait.

Male pattern baldness (MPB) is a polygenic trait that affects the majority of European men. Here, Yap et al. estimate heritability, partitioned by autosomes and the X-chromosome, of MPB in the UK Biobank cohort, perform GWAS for MPB and find genetic correlation with other sex-specific traits.

Male pattern baldness and incidence of prostate cancer: A systematic review and meta-analysis

BACKGROUND

The relationship between male pattern baldness and incidence of prostate cancer remains inconclusive. Hence, we performed the present meta-analysis based on all eligible cohort and case-control studies.

METHODS

A comprehensive literature search was performed in October 2017 based on PubMed and Web of Science databases. Pooled relative risk (RR) and its 95% confidence interval (95% CI) was calculated with a DerSimonian and Laird random-effects model.

RESULTS

A total of 15 studies were included in this meta-analysis. Overall, no statistically significant association between baldness (any pattern) and prostate cancer risk was identified (RR: 1.03, 95% CI 0.96-1.11). There was obvious heterogeneity across included studies (P < .078 for heterogeneity, I = 36.4%). When subgroup analysis by types of baldness, a statistically significant association was observed for vertex baldness (RR 1.24, 95% CI 1.05-1.46) but not for other types of baldness.

CONCLUSION

Individuals with vertex baldness may have an increased risk of prostate cancer. Given the obvious heterogeneity and null results in overall analysis and most of subgroup analyses, further large well-designed prospective cohort studies are warranted to confirm our preliminary findings.

A hypothetical pathogenesis model for androgenic alopecia: clarifying the dihydrotestosterone paradox and rate-limiting recovery factors

Androgenic alopecia, also known as pattern hair loss, is a chronic progressive condition that affects 80% of men and 50% of women throughout a lifetime. But despite its prevalence and extensive study, a coherent pathology model describing androgenic alopecia's precursors, biological step-processes, and physiological responses does not yet exist. While consensus is that androgenic alopecia is genetic and androgen-mediated by dihydrotestosterone, questions remain regarding dihydrotestosterone's exact role in androgenic alopecia onset. What causes dihydrotestosterone to increase in androgenic alopecia-prone tissues? By which mechanisms does dihydrotestosterone miniaturize androgenic alopecia-prone hair follicles? Why is dihydrotestosterone also associated with hair growth in secondary body and facial hair? Why does castration (which decreases androgen production by 95%) stop pattern hair loss, but not fully reverse it? Is there a relationship between dihydrotestosterone and tissue remodeling observed alongside androgenic alopecia onset? We review evidence supporting and challenging dihydrotestosterone's causal relationship with androgenic alopecia, then propose an evidence-based pathogenesis model that attempts to answer the above questions, account for additionally-suspected androgenic alopecia mediators, identify rate-limiting recovery factors, and elucidate better treatment targets. The hypothesis argues that: (1) chronic scalp tension transmitted from the galea aponeurotica induces an inflammatory response in androgenic alopecia-prone tissues; (2) dihydrotestosterone increases in androgenic alopecia-prone tissues as part of this inflammatory response; and (3) dihydrotestosterone does not directly miniaturize hair follicles. Rather, dihydrotestosterone is a co-mediator of tissue dermal sheath thickening, perifollicular fibrosis, and calcification - three chronic, progressive conditions concomitant with androgenic alopecia progression. These conditions remodel androgenic alopecia-prone tissues - restricting follicle growth space, oxygen, and nutrient supply - leading to the slow, persistent hair follicle miniaturization characterized in androgenic alopecia. If true, this hypothetical model explains the mechanisms by which dihydrotestosterone miniaturizes androgenic alopecia-prone hair follicles, describes a rationale for androgenic alopecia progression and patterning, makes sense of dihydrotestosterone's paradoxical role in hair loss and hair growth, and identifies targets to further improve androgenic alopecia recovery rates: fibrosis, calcification, and chronic scalp tension.

No effect of AR polyG polymorphism on spinal and bulbar muscular atrophy phenotype

BACKGROUND AND PURPOSE

Disease severity varies considerably among patients with Spinal and Bulbar Muscular Atrophy (SBMA). Our aim was to investigate the role of androgen receptor (AR) polymorphic repeats in SBMA phenotype.

METHODS

We analyzed the length of AR polyQ and polyG tracts in 159 SBMA patients.

RESULTS

No relationship between polyG size or polyG/polyQ haplotypes and clinical phenotype was found. An independent negative correlation between polyQ-length and onset of weakness was confirmed (P < 0.001).

CONCLUSIONS

The negative results of our study prompt to continue the search for potential disease modifiers in SBMA outside the AR gene.

Circulating and intraprostatic sex steroid hormonal profiles in relation to male pattern baldness and chest hair density among men diagnosed with localized prostate cancers

BACKGROUND

Prospective cohort studies of circulating sex steroid hormones and prostate cancer risk have not provided a consistent association, despite evidence from animal and clinical studies. However, studies using male pattern baldness as a proxy of early-life or cumulative androgen exposure have reported significant associations with aggressive and fatal prostate cancer risk. Given that androgens underlie the development of patterned hair loss and chest hair, we assessed whether these two dermatological characteristics were associated with circulating and intraprostatic concentrations of sex steroid hormones among men diagnosed with localized prostate cancer.

METHODS

We included 248 prostate cancer patients from the NCI Prostate Tissue Study, who answered surveys and provided a pre-treatment blood sample as well as fresh frozen adjacent normal prostate tissue. Male pattern baldness and chest hair density were assessed by trained nurses before surgery. General linear models estimated geometric means and 95% confidence intervals (95%CIs) of each hormone variable by dermatological phenotype with adjustment for potential confounding variables. Subgroup analyses were performed by Gleason score (<7 vs ≥7) and race (European American vs. African American).

RESULTS

We found strong positive associations of balding status with serum testosterone, dihydrotestosterone (DHT), estradiol, and sex hormone-binding globulin (SHBG), and a weak association with elevated intraprostatic testosterone. Conversely, neither circulating nor intraprostatic sex hormones were statistically significantly associated with chest hair density. Age-adjusted correlation between binary balding status and three-level chest hair density was weak (r = 0.05). There was little evidence to suggest that Gleason score or race modified these associations.

CONCLUSIONS

This study provides evidence that balding status assessed at a mean age of 60 years may serve as a clinical marker for circulating sex hormone concentrations. The weak-to-null associations between balding status and intraprostatic sex hormones reaffirm differences in organ-specific sex hormone metabolism, implying that other sex steroid hormone-related factors (eg, androgen receptor) play important roles in organ-specific androgenic actions, and that other overlapping pathways may be involved in associations between the two complex conditions.

Study of gene expression alteration in male androgenetic alopecia: evidence of predominant molecular signalling pathways

BACKGROUND

Male androgenetic alopecia (AGA) is the most common form of hair loss in men. It is characterized by a distinct pattern of progressive hair loss starting from the frontal area and the vertex of the scalp. Although several genetic risk loci have been identified, relevant genes for AGA remain to be defined.

OBJECTIVES

To identify biomarkers associated with AGA.

METHODS

Molecular biomarkers associated with premature AGA were identified through gene expression analysis using cDNA generated from scalp vertex biopsies of hairless or bald men with premature AGA, and healthy volunteers.

RESULTS

This monocentric study reveals that genes encoding mast cell granule enzymes, inflammatory mediators and immunoglobulin-associated immune mediators were significantly overexpressed in AGA. In contrast, underexpressed genes appear to be associated with the Wnt/β-catenin and bone morphogenic protein/transforming growth factor-β signalling pathways. Although involvement of these pathways in hair follicle regeneration is well described, functional interpretation of the transcriptomic data highlights different events that account for their inhibition. In particular, one of these events depends on the dysregulated expression of proopiomelanocortin, as confirmed by polymerase chain reaction and immunohistochemistry. In addition, lower expression of CYP27B1 in patients with AGA supports the notion that changes in vitamin D metabolism contributes to hair loss.

CONCLUSIONS

This study provides compelling evidence for distinct molecular events contributing to alopecia that may pave the way for new therapeutic approaches.

Height, selected genetic markers and prostate cancer risk: results from the PRACTICAL consortium

BACKGROUND

Evidence on height and prostate cancer risk is mixed, however, recent studies with large data sets support a possible role for its association with the risk of aggressive prostate cancer.

METHODS

We analysed data from the PRACTICAL consortium consisting of 6207 prostate cancer cases and 6016 controls and a subset of high grade cases (2480 cases). We explored height, polymorphisms in genes related to growth processes as main effects and their possible interactions.

RESULTS

The results suggest that height is associated with high-grade prostate cancer risk. Men with height >180 cm are at a 22% increased risk as compared to men with height <173 cm (OR 1.22, 95% CI 1.01-1.48). Genetic variants in the growth pathway gene showed an association with prostate cancer risk. The aggregate scores of the selected variants identified a significantly increased risk of overall prostate cancer and high-grade prostate cancer by 13% and 15%, respectively, in the highest score group as compared to lowest score group.

CONCLUSIONS

There was no evidence of gene-environment interaction between height and the selected candidate SNPs.Our findings suggest a role of height in high-grade prostate cancer. The effect of genetic variants in the genes related to growth is seen in all cases and high-grade prostate cancer. There is no interaction between these two exposures.

A Practical Approach to the Diagnosis and Management of Hair Loss in Children and Adolescents

Hair loss or alopecia is a common and distressing clinical complaint in the primary care setting and can arise from heterogeneous etiologies. In the pediatric population, hair loss often presents with patterns that are different from that of their adult counterparts. Given the psychosocial complications that may arise from pediatric alopecia, prompt diagnosis and management is particularly important. Common causes of alopecia in children and adolescents include alopecia areata, tinea capitis, androgenetic alopecia, traction alopecia, trichotillomania, hair cycle disturbances, and congenital alopecia conditions. Diagnostic tools for hair loss in children include a detailed history, physical examination with a focused evaluation of the child’s hair and scalp, fungal screens, hair pull and tug test, and if possible, light microscopy and/or trichoscopy. Management of alopecia requires a holistic approach including psychosocial support because treatments are only available for some hair loss conditions, and even the available treatments are not always effective. This review outlines the clinical presentations, presents a diagnostic algorithm, and discusses management of these various hair loss disorders.

Androgenetic alopecia: a review

PURPOSE

Androgenetic alopecia, commonly known as male pattern baldness, is the most common type of progressive hair loss disorder in men. The aim of this paper is to review recent advances in understanding the pathophysiology and molecular mechanism of androgenetic alopecia.

METHODS

Using the PubMed database, we conducted a systematic review of the literature, selecting studies published from 1916 to 2016.

RESULTS

The occurrence and development of androgenetic alopecia depends on the interaction of endocrine factors and genetic predisposition. Androgenetic alopecia is characterized by progressive hair follicular miniaturization, caused by the actions of androgens on the epithelial cells of genetically susceptible hair follicles in androgen-dependent areas. Although the exact pathogenesis of androgenetic alopecia remains to be clarified, research has shown that it is a polygenetic condition. Numerous studies have unequivocally identified two major genetic risk loci for androgenetic alopecia, on the X-chromosome AR⁄EDA2R locus and the chromosome 20p11 locus.

CONCLUSIONS

Candidate gene and genome-wide association studies have reported that single-nucleotide polymorphisms at different genomic loci are associated with androgenetic alopecia development. A number of genes determine the predisposition for androgenetic alopecia in a polygenic fashion. However, further studies are needed before the specific genetic factors of this polygenic condition can be fully explained.

Perception of Hair Transplant for Androgenetic Alopecia

Importance

Hair transplant is among the most common cosmetic services sought by men, with more than 11 000 procedures performed in 2014. Despite its growing popularity, the effect of hair transplant on societal perceptions of youth, attractiveness, or facets of workplace and social success is unknown.

Objectives

To determine whether hair transplant improves observer ratings of age, attractiveness, successfulness, and approachability in men treated for androgenetic alopecia and to quantify the effect of hair transplant on each of these domains.

Design, Setting, and Participants

A randomized controlled experiment was conducted from November 10 to December 6, 2015, using web-based surveys featuring photographs of men before and after hair transplant. One hundred twenty-two participants recruited through various social media platforms successfully completed the survey. Observers were shown 2 side-by-side images of each man and asked to compare the image on the left with the one on the right. Of 13 pairs of images displayed, 7 men had undergone a hair transplant procedure and 6 had served as controls. Observers evaluated each photograph using various metrics, including age, attractiveness, successfulness, and approachability. A multivariate analysis of variance was performed to understand the effect of hair transplant on observer perceptions. Planned posthypothesis testing was used to identify which variables changed significantly as a result of the transplant.

Main Outcomes and Measures

Observer ratings of age (in number of years younger) and attractiveness, successfulness, and approachability (on a scale of 0 to 100; scores higher than 50 indicate a positive change).

Results

Of the 122 participants in the survey, 58 were men (47.5%); mean (range) age was 27.1 (18-52) years. The initial multivariate analysis of variance revealed a statistically significant multivariate effect for transplant (Wilks λ = 0.9646; P < .001). Planned posthypothesis analyses were performed to examine individual differences across the 4 domains. Findings determined with t tests showed a significant positive effect of hair transplant on observers' perceptions of age (mean [SD] number of years younger, 3.6 [2.9] years; P < .001), attractiveness (mean [SD] score, 58.5 [17.5]; P < .001), successfulness (mean [SD] score, 57.1 [17.1]; P = .008), and approachability (mean [SD] score, 59.2 [18.1]; P = .02).

Conclusions and Relevance

Men were perceived as being younger and more attractive by casual observers after undergoing hair transplant. Participants also rated posttransplant faces as appearing more successful and approachable relative to their pretransplant counterparts. These aspects have been shown to play a substantial role in both workplace and social success, and these data demonstrate that hair transplant can improve ratings universally across all 4 domains.

Level of Evidence

NA.