Following historical "tracks" of hair follicle miniaturisation in patterned hair loss: Are elastin bodies the forgotten aetiology?

Pattern hair loss (PHL) is a chronic regressive condition of the scalp, where follicular miniaturisation and decreased scalp hair coverage occurs in affected areas. In all PHL cases, there is a measurable progressive shortening of the terminal hair growth duration, along with reduced linear growth rates. In both genders, PHL initially shows an increase in short telogen hairs ≤30 mm in length, reflecting a cycle completion of under 6 months in affected terminal hair follicles. To understand the miniaturisation process, we re-examine the dynamics of miniaturisation and ask the question, "why do miniaturised hair follicles resist treatment?" In the light of recent developments in relation to hair regeneration, we looked back in the older literature for helpful clues "lost to time" and reprise a 1978 Hermann Pinkus observation of an array of elastin deposits beneath the dermal papilla following subsequent anagen/telogen transitions in male balding, originally described by Arao and Perkins who concluded that these changes provide a "morphologic marker of the entire biologic process in the balding scalp." Thus, we have reviewed the role of the elastin-like bodies in hair pathology and we propose that alterations in elastin architecture may contribute to the failure of vellus-like hair reverting back to their terminal status and may indicate a new area for therapeutic intervention.

Placebo-controlled dose-effect studies with topical minoxidil 2% or 5% in male-patterned hair loss treated with oral finasteride employing an analytical and exhaustive study protocol.

BACKGROUND: Drug trials for male-pattern hair loss (MPHL) did not investigate hair cycling. MATERIALS AND METHODS: Male-pattern hair loss volunteers (n = 22) took oral finasteride 1 mg daily with randomly either MTS5% or control lotion (1 mL/d). After 12 months on oral drug, 14 were randomized for a dose-effect study of topical minoxidil 2% or 5%. Each 3-month "on-lotion" was followed by a 3-month "off-lotion." RESULTS: Exogen release and anagen initiation from pre-existing but functionally deficient follicles occurred mainly during combined dug treatment. Anagen initiation by topical minoxidil 5% could not be maintained by oral finasteride. As compared with control males, the compound index of hair growth raised from 30% at baseline up to 60% within 3 months of combined drug regimen which is better than oral drug only (no change) but still far beyond normalization of productivity (considered as 100%). There was no obvious transformation of miniaturized hair follicles into terminal hair-producing follicles, and the activation of miniaturized hair follicles was not clinically relevant (slow growth and short duration of anagen). CONCLUSIONS: Benefit with oral finasteride and topical 5% minoxidil (1 mL, 1 per day) resulted from initiation of anagen in deficient terminal follicles without increased growth rates.

Viable terminal scalp hair follicles constitute a necessary and sufficient biological end-organ that conditions clinical efficacy of finasteride in males with male pattern hair loss without implying reversal of miniaturized follicles.

BACKGROUND: Biopsy-based "reversal hypothesis" claimed conversion of miniaturized hair follicles into terminal ones for the improvement of male pattern hair loss (MPHL) with FDA-approved drugs. MATERIALS AND METHODS: MPHL volunteers (n = 13) completed a 24-month phototrichogram study. After 2 months no-treatment, panellists took finasteride 1mg daily for 2 years. Hair changes from the best responder would explain the nature of improved hair growth. RESULTS: Due to the wide range of hair growth variables, no parameter was statistically significantly changed by finasteride in the group. Clinically there were 4 worse, 6 no change, 2 slightly and 1 moderately improved subject associated with turning telogen/empty terminal follicles into anagen after 12- and 24-month finasteride. From 113 miniaturized hair (diameters ≤ 30 µm) at baseline, 79 were still miniature hair after 2 years on finasteride. No hair were found at the remaining mapped sites except for 2 terminal hairs considered a probabilistic "uncertainty." CONCLUSION: Moderate hair improvement resulted from increased productivity of deficient terminal follicles, but not yet irreversibly affected at baseline without implication of miniaturized hair follicles. The latter further regressed even with oral intake of finasteride. The data suggest the rejection of the "reversal hypothesis" unless proven otherwise with duly validated methods.

Maintenance of optimised hair growth from viable terminal scalp hair follicles at baseline with oral finasteride in male pattern hair loss and first evidence of a "drug dependency" and a post-finasteride "rebound effect".

BACKGROUND: Analytical measures for the pharmacodynamics understanding of drug induced scalp hair responses are lacking. MATERIALS AND METHODS: The present study measured in detail dynamics of hair productivity on two scalp test sites showing male pattern hair loss. The natural regression decay rate established after 2 years without treatment was followed by treatment with daily oral intake of 1 mg finasteride. RESULTS: While terminal hair (diameter ≥40 µm) were maintained "on-drug," within 30 months "off-drug" MPHL significantly worsened as 94% terminal hair miniaturised and became unproductive. Accordingly, the viable drug responding follicles were qualified as "finasteride dependent" unravelling a hereto unreported "rebound effect" after interruption of the drug intake. Interestingly, the transformation of terminal hair into miniaturised hair occurred only after 12 months without treatment, that is the time necessary to complete a clinically significant full hair cycle initiated during the drug intake. This explains why exogen hair release and miniaturisation occurred only between 12 and 30 months "off-drug" while resistant hair grew also slower. CONCLUSION: Drug dependency and rebound phenomenon are new findings along with evidence against the hypothesis claiming that terminal hair growth arises from initial vellus hair follicles in drug-treated MPHL.

Why care about linear hair growth rates (LHGR)? a study using in vivo imaging and computer assisted image analysis after manual processing (CAIAMP) in unaffected male controls and men with male pattern hair loss (MPHL).

BACKGROUND: The words "hair growth" frequently encompass many aspects other than just growth. OBJECTIVES: Report on a validation method for precise non-invasive measurement of thickness together with linear hair growth rates of individual hair fibres. To verify the possible correlation between thickness and linear growth rate of scalp hair in male pattern hair loss as compared with healthy male controls. MATERIALS AND METHODS: To document the process of validation of hair growth measurement from in vivo image capturing and manual processing, followed by computer assisted image analysis. We analysed 179 paired images obtained with the contrast-enhanced-phototrichogram method with exogen collection (CE-PTG-EC) in 13 healthy male controls and in 87 men with male pattern hair loss (MPHL). RESULTS: There was a global positive correlation between thickness and growth rate (ANOVA; p<0.0001) and a statistically significantly (ANOVA; p<0.0005) slower growth rate in MPHL as compared with equally thick hairs from controls. Finally, the growth rate recorded in the more severe patterns was significantly (ANOVA; P ≤ 0.001) reduced compared with equally thick hair from less severely affected MPHL or controls subjects. CONCLUSION: Reduced growth rate, together with thinning and shortening of the anagen phase duration in MPHL might contribute together to the global impression of decreased hair volume on the top of the head. Amongst other structural and functional parameters characterizing hair follicle regression, linear hair growth rate warrants further investigation, as it may be relevant in terms of self-perception of hair coverage, quantitative diagnosis and prognostic factor of the therapeutic response.

Exogen hair characterization in human scalp.

BACKGROUND/AIM: Classically, the hair cycle is described as a sequence of three successive phases: a hair-growth phase named anagen, a regression phase or catagen and a resting phase or telogen. In rodents, it appears that the resting hair follicle population contains also a new phase that has been identified recently as the exogen phase of the hair cycle. This phase leads to the release of the telogen club and results in hair shedding. The aim of this paper is to propose a method that is applicable to humans and that is able to discriminate the two components of the resting hair population i.e. the telogen and the exogen hair follicles. METHODS: We used non-invasive approaches to entrap exogen scalp hair into silicon-based polymers. We also extracted growing and non-growing hair with a calibrated dynamometer. We characterized differences between anagen, catagen, telogen and exogen root ends with histochemical stains and with the scanning electron microscope. Furthermore, we documented all known hair-cycle stages with the contrast-enhanced phototrichogram (CE-PTG) technique. RESULTS: We demonstrated that anagen and telogen hair are firmly anchored to the hair follicle and that cohesion forces are correlated with hair thickness. On the contrary, exogen hair are passively retained within the hair follicle. Among the resting hair population, telogen clubs retain cellular elements of the outer root sheaths that are not found on exogen hair. The specificity of the new exogen collection method was documented with the simultaneous use of the CE-PTG method: indeed anagen, catagen and telogen follicles remain unaffected by the exogen extraction procedure. CONCLUSION: Exogen hair can be sampled specifically from the human scalp with a new non-invasive method. Our data suggest that the casual levels of exogen hair, in normal individuals and under the present experimental conditions, are usually less than seven hair per cm(2).

Female patients complaining about hair loss: documentation of defective scalp hair dynamics with contrast-enhanced phototrichogram.

BACKGROUND: The complaint of chronic hair loss frequently affects female subjects and there is little or no objective technology available in the general dermatology or even in the hair clinics to guide the observer in the management of the patient. The purpose of this report is to share the results of refined hair growth measurements that were collected in 92 female subjects complaining about hair loss. METHODS: Clinically they were classified as having a patterned hair loss according to Ludwig (L; n=50), diffuse hair loss (D; n=13) or no visible hair loss but complaining of hair shedding (N; n=29). Two scalp sites on the top of the head and one occipital site were investigated after clipping by close-up photography before and after a hair dye (contrast enhancement, CE). Forty-eight hours later a new photograph was taken after CE in view of phototrichogram analysis (CE-PTG). Finally a last hair clip was performed 30 days later and hair thickness and length determined for linear growth measurements (LHGR). RESULTS: Herein we confirm that the top of the head shows usually a higher hair density than occipital sites, a physiological observation that applies both to men and women. From the technological perspective, we also document that CE improves hair detection in all sites. Interestingly, in affected patients (L and D) the relative increase of hair counts after CE was much higher (range +22.4% to +28.3%) compared with apparently unaffected females (N; range +8.2% to +9.7%). This increase in hair counts was only due in part to the presence of less pigmented thinning hair (thickness less than 40 microm). Such thin hairs were found in statistically significantly higher proportions in younger patients with mildly severe (grade I) patterned alopecia (Ludwig: L). In other patients with hair loss and in more severe forms of patterned alopecia - especially in older patients - the thin hair is not detected in abnormal proportions. In all sites slower growth rates and decreased anagen percentages indicate a defective hair replacement programme distinguishing L patterns from diffuse hair loss and from apparently unaffected patients complaining of chronic hair loss. Globally, we also noted that increasing age is associated with significant regression of scalp hair (decreased hair counts, thinner hair and slower LHGR). CONCLUSION: On the basis of the present data together with female data from the literature and our own studies in male subjects, we suggest a three-step mechanism leading to hair loss 1. Shortening of growth phase the hair cycle with maintained thick hair, i.e. more frequent hair cycling that leads to more hair shedding. 2. Intermittent production of short thin hair, i.e. morphological evidence of miniaturisation. 3. Very occasional or almost no hair production, i.e. dormant follicles or irreversible follicular atrophy. Depending on the genetic background, hormonal microenvironment in the scalp and conditioning of individual hair follicle bio-responses, female and male patterned hair loss may end up into different phenotypes.

Recent findings with computerized methods for scalp hair growth measurements.

Sensitive tools have been developed in order to monitor hair loss and treatment responses. Recently the Tricho-Scan was presented (by RH) as such a method which combines epiluminescence microscopy (ELM) with automatic digital image analysis. Herewith new TrichoScan data obtained from 10 women and 21 men with androgenetic hair loss after 6 mo of treatment with 5%-minoxidil are presented. Even in this small cohort of patients, we noticed a significant increase of hair density, cumulative hair thickness and terminal hair counts. Alternative methods were developed during a human alopecia investigation and research technology (HAIR Technology) programme at Skinterface. This involves contrast-enhancement, image acquisition, and processing by qualified technicians followed by computer-assisted image analysis. The specific identification of exogen hair, further adds to this very refined non-invasive investigative method for hair follicle function investigation. Regional variations of hair growth dynamics do exist in the human scalp such as in female patients complaining of hair loss, scalp hair density and growth on top of the head differs significantly from the occipital site. Finally, from transversal studies and from detailed monitoring of subsequent hair cycles during longitudinal studies, data were obtained that support the fact that shortening of hair cycle, slowing down of growth rates and thinning of hair shafts are heralding hair miniaturisation. In the workshop the TrichoScan, the method of Canfield and Skinterface have been shown.

Hair cycle and hair pigmentation: dynamic interactions and changes associated with aging.

The tight coupling of hair follicle melanogenesis to the hair growth cycle dramatically distinguishes follicular melanogenesis from the continuous melanogenesis of the epidermis. Cyclic re-construction of an intact hair follicle pigmentary unit occurs optimally in all scalp hair follicles during only the first 10 hair cycles, i.e. by approximately 40 years of age. Thereafter there appears to be a genetically regulated exhaustion of the pigmentary potential of each individual hair follicle leading to the formation of true gray and white hair. Pigment dilution results primarily from a reduction in tyrosinase activity within hair bulbar melanocytes. Thereafter, sub-optimal melanocyte-cortical keratinocyte interactions, and defective migration of melanocytes from a reservoir in the upper outer root sheath to the pigment-permitting microenvironment close to the follicular papilla of the hair bulb, will all disrupt normal function of the pigmentary unit. Evidence from studies on epidermal melanocyte aging suggest that reactive oxygen species-mediated damage to nuclear and mitochondrial DNA may lead to mutation accumulation in bulbar melanocytes. Parallel dysregulation of anti-oxidant mechanisms or pro/anti-apoptotic factors is also likely to occur within the cells. Pigment loss in canities may also affect keratinocyte proliferation and differentiation, providing the tantalizing suggestion that melanocytes in the hair follicle contribute far more that packages of pigment alone. Here, we review the current state of knowledge of the development, regulation and control of the aging human hair follicle pigmentary system in relation with hair cycling. The exploitation of recently available methodologies to manipulate hair follicle melanocytes in vitro, and the observations that melanocytes remain in senile white hair follicles that can be induced to pigment in culture, raises the possibility of someday reversing canities. The perspective of rejuvenation of the whole hair follicle apparatus are still part of the dream but optimising its functional properties is clinically relevant and is close to reality. Finally as hair color influences its visibility when optical methods such as scalp photography are used to count hair fibers, the attention is drawn to possible interpretations of statistically significant changes in visible hair. Such changes may not exclusively be related to improved hair growth itself but also to changes in natural hair color that makes the hair more visible with the method used to count hairs.

Thickness, medullation and growth rate of female scalp hair are subject to significant variation according to pigmentation and scalp location during ageing.

The biological importance and/or significance of human hair colour is unknown even though greying is obviously associated with ageing. In order to further characterise hair pigmentation in relation with hair growth variables we evaluated 3 scalp sites (top of the head (T): left and right and occipital(O)) in 12 untreated menopausal women (age range: 49-66 years: average 59.63 +/- 5.66) who presented complaining of hair loss and/or diffuse alopecia. Controls were 12 non menopausal sexually mature woman (7 age range 15-21 and 5 age range 38-48) not complaining of hair loss. One hair sample (whenever possible n = 60) was taken one month after clipping from T and O on each person; menopausal women were sampled twice. The following measures were performed with a light microscope: diameter (average min-max., microm), medulla (0% = absent to 100% = fully developed) and linear hair growth rate (mm/day). The hairs were categorised as pigmented (P) or non-pigmented (white, W) as compared with a black and white reference card. A total of 3343 hairs were analysed with 2-factor analysis of variance (ANOVA). A global comparison (all hairs) showed that the average diameter of W hair (67.68 microm) exceeded that of P hair (57.41 microm) (p = 0.0001) and this was maintained on all 3 scalp sites. In addition, the medulla of W hair (23.91%) appeared more developed than the medulla of P hair (12.21%) (p = 0.0001) and was more expressed in W T hairs as compared with W O hairs (p = 0.0325). There was also a significant interaction between site and pigmentation (p = 0.0074). Growth rate of W hairs (0.38 mm/d) was higher than that of P hairs (0.35 mm/d) (p = 0.0001) and there was a significant variation according to scalp sites (p = 0.0001). There was also a significant interaction between site and pigmentation (p = 0.0062) with the following rank order: O W (0.40 mm/d), T W (0.37 mm/d), O P (0.37 mm/d) and T P (0.34 mm/d). Subgroups of W and P of paired thickness in the range of 50 to 80 pm consistently showed a 10% faster growth rate of W. Previous studies have shown that growth rate and diameter declines in age and alopecia i.e. in hair thinning. Our data shows that the reduced growth rate of terminal hairs is in fact limited to the pigmented hairs. The mechanisms by which white hairs are spared these ageing changes are not yet understood. Less pigmented hairs are usually undetected by photo- graphic techniques used for drug trials. The potential role of drug induced modifications of hair pigmentation should be taken into account during the interpretation of efficacy except if contrast-enhancement has been applied.

Morphological approach to hair disorders.

The Workshop on the morphological approach to hair disorders brought together a group of clinicians involved in hair biology research. Six speakers spoke on a range of topics that can be grouped broadly into a central theme. It summarizes the evolution of medical research. The section by Tosti and coworkers describes a patient with a new unique syndrome. The section by Ferrando and colleagues provides a framework in which patients with rare hair disorders can be classified. The section by Whiting tries to define the normal anatomy of the hair follicle and both horizontal and vertical sections. It is only when normal anatomy has been absolutely defined that pathological deviations can be recognized. The section by Sinclair and coworkers attempts to estimate the reliability of histological diagnosis so that its true value of pathology can be recognized. The section by Zlotogorski and coworkers shows how accurate clinical and histological definition of disease acts as the cornerstone for gene discovery techniques. Once a causative mutation is found and a gene product identified, then the biological consequences of the altered protein product can be studied and the impact of the abnormal molecular function on hair biology can be understood. It is hoped that improved understanding of hair disease will then lead to useful therapeutic interventions. The final section by Leroy and Van Neste highlights the difficulties of evaluating therapeutic interventions in hair loss disease and proposes a new technique.

Validation and clinical relevance of a novel scalp coverage scoring method.

BACKGROUND/AIMS: Distinctive patterns of defective scalp skin coverage or alopecia have been identified by clinicians but do not help measuring the dynamics of hair changes over time. Hence, we conceived the scalp coverage scoring (SCS) method that integrates cumulative changes of hair growth or loss. In this paper, we report the results of validation studies demonstrating that the SCS can be applied in real time in the clinic or on global photographs for evaluating the severity of androgenetic alopecia (AGA) of male subjects and for monitoring changes over time. METHODS: Different panels totalling 38 different male subjects with AGA were classified according to a modified Norwood-Hamilton scale and were evaluated with the SCS system (real time or global photographs). The contrast-enhanced phototrichogram method (CE-PTG), a refined non-invasive and validated analytical technique was used for calibration purposes. RESULTS: The real time SCS was correlated with SCS on global photographs. The inter- and intra-observer variation of SCS obtained on global photographs was less than 3%. The real time SCS was negatively correlated with the clinical staging of male pattern baldness according to the modified Norwood-Hamilton scale, confirming less scalp coverage in more severly affected subjects. In 12 male subjects with AGA, after SCS evaluation of the top of the head, a 1-cm2 central target site was explored with CE-PTG. There was a significant correlation of real time SCS with the percentage of thick anagen hair (r = 0.53; P < 0.08) and with the density of thin hair (r = -0.68; P < 0.02). Changes over time as documented on global photographs (18 subjects at baseline and after 12 and 60 months) were rated by a panel of independent experts (paired photographs) who were not blinded as to time. Randomised individual photographs were also examined one at a time for SCS. This procedure documents data obtained without control of baseline photographs and establishes blinding as to time. The changes calculated from SCS (after-baseline) were correlated (r = 0.9; P < 0.0001) with the rating of the panel of experts. CONCLUSIONS: When minimum technical precautions are taken prior to the scoring session, the main points of interest of the SCS method are: Non-invasive quantitative and reproducible technique. Measures dynamics of scalp hair growth and loss. Easily applied in the hair clinic.

Contrast enhanced phototrichogram pinpoints scalp hair changes in androgen sensitive areas of male androgenetic alopecia.

BACKGROUND/AIM: In male androgenetic alopecia (AGA), global changes of scalp hair observed on many years are the cumulative result of discrete changes. Such changes reflect structural and/or functional modifications occurring at the level of individual hair follicles. The patterning of scalp hair loss is the phenotypic expression of clusters of hormone sensitive follicles located in specific scalp areas. The aim of this study was to evaluate, in 21 untreated male subjects with AGA, the relation between various hair measurements using a new validated photographic method with clinical staging (modified Norwood-Hamilton scale) as compared with five controls. METHODS: As recently demonstrated by comparison with transverse sectioning of scalp biopsies, dynamic changes occurring at the level of individual hair follicles can be accurately explored with the contrast enhanced phototrichogram technique (CE-PTG). This is a further improvement of the PTG (combined analysis of two photographs taken at 48 h interval) using contrast enhancement together with the scalp immersion proxigraphy method. Visible hair counts per unit area were first evaluated on photographs without and with CE. Then other scalp hair variables (anagen hair counts and proportion of thin hair (