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PubMed2002

Assessment of hair loss: clinical relevance of hair growth evaluation methods.

This review on hair growth measurement methods focuses on human scalp hair in the context of clinically relevant assessment of hair loss. This phenomenon is the end result of a complex combination of events closely associated with hair cycling followed by defective hair replacement. The methodological spectrum ranges from the most to the least invasive approach. All of the measurement methods referred to are critically reviewed, with their stronger and weaker aspects, in view of their potential application in the skin and hair clinic. The existence of recently developed highly resolutive noninvasive analytical methods capable of exploring almost every aspect of the dynamics of this growth and loss phenomenon allowed calibration of more global scoring method. From this review, the author concludes that a combination of a highly resolutive analytical approach with a global calibrated method seems advisable in the context of the monitoring of hair growth changes for better or worse, i.e. scalp hair growth or hair loss in the hair clinic.

Alopecia↗

PubMed2001

Identification of clustered cells in human hair follicle responsible for MMP-9 gelatinolytic activity: consequences for the regulation of hair growth.

BACKGROUND: The control of human hair follicle growth and differentiation is dependent upon several well-identified factors, including androgens, cytokines, and growth factors. In humans, alopecia androgenetica is a common aging process thought to be regulated through complex genetic imbalances, which also involve several of these crucial identified factors (and probably others not yet characterized), alone or in combination. Among these factors, epidermal growth factor (EGF), as well as pro-inflammatory cytokines, play a pivotal role, as evidenced by their direct inhibitory effects on hair growth both in vitro and in vivo. Following such treatments, the in vitro growth of hair follicles was rapidly arrested and deleterious modifications of hair morphology were also observed. AIM: Because these cytokines act, at least partly, through the induction of matrix metalloproteinases (MMP), and because tissue remodeling occurs during the hair cycle, we attempted to identify and localize MMP in the human pilosebaceous unit. METHOD: We used zymography to observe human hair follicles in culture in vitro. RESULTS: We observed that human hair follicles in culture in vitro mainly and almost exclusively produce MMP-2 and MMP-9 gelatinolytic activities. Furthermore, after stimulation with EGF, tumor necrosis factor-alpha (TNF-alpha), or interleukin-1alpha (IL-1alpha), MMP-9 production was strongly increased. Using immunohistochemistry, we then precisely localized MMP-9 in the lower part of the inner root sheath (Henle's layer) of control human anagen hair follicles. CONCLUSIONS: Cytokine- and EGF-induced upregulation of MMP-9 in the lower epithelial compartment of the human hair bulb is a major mechanism through which hair follicle involution, observed in alopecia, may occur.

Cells, Cultured↗

PubMedDate not supplied

The effect of hair color on the incorporation of methadone into hair in the rat.

Six groups of six male, hooded, Lister rats were administered methadone in their drinking water over the concentration range 0-0.25 mg/mL for 6 weeks. Black pigmented and white nonpigmented hair and trunk blood samples were collected. Plasma and alkali digests of hair were analyzed for methadone by radioimmunoassay. Hair melanin content was estimated in digests by turbidimetry. Oral methadone intake rose in a linear fashion over the six dose groups, and plasma methadone concentration followed a similar trend. The methadone content of both white and black hair increased over the six dose groups, but concentrations were significantly higher in black compared with white hair. The mean ratio of methadone concentration between black and white hair was 21.3:1, and the mean ratio in hair melanin content was 3.5:1. The results demonstrate that pigmented hair incorporates larger quantities of methadone than nonpigmented hair and that methadone binds with higher affinity to the pigmented components as compared with other components of hair.

Administration, Oral↗

PubMed2001

Prolactin signaling influences the timing mechanism of the hair follicle: analysis of hair growth cycles in prolactin receptor knockout mice.

Pituitary PRL regulates seasonal hair follicle growth cycles in many mammals. Here we present the first evidence implicating PRL in the nonseasonal, wave-like pelage replacement of laboratory mice. In this study we show that messenger RNA transcripts encoding the one long and two short forms of PRL receptor are present in the skin of adult and neonate mice. The receptor protein was immunolocalized to the hair follicle as well as the epidermis and sebaceous glands. Furthermore, PRL messenger RNA was detected within skin extracts, suggesting a possible autocrine/paracrine role. Analysis of the hair growth phenotype of PRL gene-disrupted mice (PRLR(-/-)) revealed a change in the timing of hair cycling events. Although no hair follicle development differences were noted in PRLR(-/-) neonates, observations of the second generation of hair growth revealed PRLR(-/-) mice molted earlier than wild types (PRLR(+/+)). The advance was greater in females (29 days) than in males (4 days), resulting in the elimination of the sexual dimorphism associated with murine hair replacement. Heterozygotes were intermediate between PRLR(-/-) and PRLR(+/+) mice in molt onset. Once initiated, the pattern and progression of the molt across the body were similar in all genotypes. Although all fiber types were present and appeared structurally normal, PRLR(-/-) mice had slightly longer and coarser hair than wild types. These findings demonstrate that PRL has an inhibitory effect on murine hair cycle events. The pituitary PRL regulation of hair follicle cycles observed in seasonally responsive mammals may be a result of pituitary PRL interacting with a local regulatory mechanism.

Animals↗

PubMed2000

The incorporation of cocaine and metabolites into hair: effects of dose and hair pigmentation.

The relationship between xenobiotic concentrations in hair and the degree of systemic xenobiotic exposure is poorly defined. The purpose of this study was to evaluate the effect of dose, time, and pigment on the hair incorporation of cocaine (COC) and its metabolites, benzoylecgonine (BE), ecgonine methyl ester (EME), and norcocaine (NCOC). COC was administered by the i.p. route to male Long-Evans (LE) rats at three doses (5, 10, and 20 mg/kg) once daily for 5 days. Fourteen days after the initial injection, the hair was collected and analyzed by gas chromatography/mass spectrometry for the compounds of interest. COC, EME, and NCOC were preferentially incorporated into pigmented hair in a dose-dependent manner. None of the analytes were detected in nonpigmented hair. The plasma pharmacokinetic profile of each analyte was determined at each dose. After normalizing for the plasma concentrations, the incorporation of COC into pigmented hair was 2 orders of magnitude greater than BE. The time course of COC and metabolite distribution into hair was also investigated from 1 h to 14 days after a single dose. After COC disappears from plasma, there is a 3-day delay before maximal hair concentrations are reached in pigmented hair. In nonpigmented hair, concentrations of BE and COC did not exceed 0.25 ng/mg and were undetectable after 4 h and 2 days, respectively. This study demonstrates that the pigment-mediated differences in the incorporation of COC and its metabolites noted at 14 days after dosing are also evident a few hours after drug administration.

Animals↗

PubMed1997

Genetically null mice reveal a central role for epidermal growth factor receptor in the differentiation of the hair follicle and normal hair development.

Mice harboring a targeted disruption of the epidermal growth factor receptor (EGFR) allele exhibit a severely disorganized hair follicle phenotype, fuzzy coat, and systemic disease resulting in death before 3 weeks. This skin phenotype was reproduced in whole skin grafts and in grafts of EGFR null hair follicle buds onto nude mice, providing a model to evaluate the natural evolution of skin lacking the EGFR. Hair follicles in grafts of null skin did not progress from anagen to telogen and scanning electron micrografts revealed wavy, flattened hair fibers with cuticular abnormalities. Many of the EGFR null hair follicles in the grafted skin were consumed by an inflammatory reaction resulting in complete hair loss in 67% of the grafts by 10 weeks. Localization of follicular differentiation markers including keratin 6, transglutaminase, and the hair keratins mHa2 and hacl-1 revealed a pattern of premature differentiation within the null hair follicles. In intact EGFR null mice, proliferation in the interfollicular epidermis, but not hair follicles, was greatly decreased in the absence of EGFR. In contrast, grafting of EGFR null skin resulted in a hyperplastic response in the epidermis that did not resolve even after 10 weeks, although the wound-induced hyperplasia in EGFR wild-type grafts had resolved within 3 to 4 weeks. Thus, epithelial expression of the EGFR has complex functions in the skin. It is important in delaying follicular differentiation, may serve to protect the hair follicle from immunological reactions, and modifies both normal and wound-induced epidermal proliferation but seems dispensable for follicular proliferation.

Age Factors↗

PubMed1990

Organ culture of human scalp hair follicles: effect of testosterone and oestrogen on hair growth.

Whole human scalp hair follicles were cultured. The follicles were dissected from skin pieces of normal scalp and put into 1.5 ml of incubation medium in a closed 5 ml glass tube under an atmosphere of 95% O2 and 5% CO2. The tube was rolled at 15 rpm at 36 degrees C. Remarkable hair growth was noticed for 7 to 8 days. Hair root sheaths also grew with the hair shafts. The structure of the hair bulbs was well maintained for at least 6 days, and then the hair matrix cells started to degenerate. Fetal calf serum was not essential for hair growth in vitro, but increased the growth rate slowly. Testosterone and oestrogen inhibited hair growth in vitro to a similar extent. The minimum effective doses of both hormones to suppress hair growth were around 5 ng/ml, which corresponds well to the normal plasma level of testosterone in adult males in vivo, suggesting that scalp hair growth may be critically controlled by testosterone in adult males.

Autoradiography↗

PubMed1995

Radioimmunoassay of drugs of abuse in hair. Part 2: The determination of methadone in the hair of known drug users.

This communication addresses the analytical problems associated with the analysis of hair specimens from known users and misusers of the synthetic opioid methadone. An adapted radioimmunoassay and a previously developed preanalytical decontamination procedure have been applied to samples from known drug users. The removal of drugs from the hair surface by washing and the effect of proprietary hair treatments on methadone entrapped in the hair have also been investigated. Pre-analytical washing reduced methadone levels by up to 29%, whilst hair colouration and peroxide bleaching were found to reduce levels by up to 21% and 50% respectively. Methadone assay of extracts from dated hair segments were shown to provide long-term histories of methadone intake, under controlled and non-controlled conditions. Evidence that a dose relationship between hair drug levels and intake may exist is presented. Results of hair analysis, expressed as ng methadone/mg hair, from drug users (range 0.20-10.63) are compared to a pre-determined cut-off of 0.1 ng methadone/mg hair, obtained from the analysis of a known drug free population (n = 23).

Chemistry Techniques, Analytical↗

PubMed1994

Human hair growth in vitro: a model for the study of hair follicle biology.

The factors that regulate hair follicle growth are still poorly understood. In vitro models may be useful in elucidating some aspects of hair follicle biology. We have developed an in vitro human hair growth model that enables us to maintain isolated human hair follicles for up to 10 days, during which time they continue to grow at an in vivo rate producing a keratinised hair fibre. We have shown that epidermal growth factor (EGF) in our system mimics the in vivo depilatory action of EGF in sheep, and suggest that this occurs as a result of EGF stimulating outer root sheath (ORS) cell proliferation which results in the disruption of normal mechanisms of cell-cell interaction in the hair follicle. We identify transforming growth factor-beta (TGF-beta) as a possible negative regulator of hair follicle growth and show that physiological levels of insulin-like growth factor-I (IGF-I) can support the same rates of hair follicle growth as supraphysiological levels of insulin. Furthermore, in the absence of insulin hair follicles show premature entry into a catagen-like state. This is prevented by physiological levels of IGF-I. Finally we demonstrate that the hair follicle is an aerobic glycolytic, glutaminolytic tissue and discuss the possible implications of this metabolism.

Aerobiosis↗

PubMed1999

Determination of hair cell degeneration and hair cell death in neomycin treated cultures of the neonatal rat cochlea.

The spatial-temporal course of hair cell degeneration and hair cell death was examined in the mammalian cochlea following aminoglycoside treatment. Organotypic cultures were established from postnatal rats (P3) and treated with 1 mM neomycin sulfate for 12-48 h and analyzed using a live/dead assay under epifluorescence microscopy. Live hair cells were labeled with calcein, a probe whose fluorescence and cellular retention depends upon intracellular esterase activity and cell-membrane integrity, respectively. Hair cell death was determined by ethidium homodimer-1, a probe that can enter cells with compromised cell membranes only. Inside the cell it binds to DNA. Hair cell morphology was also examined using phalloidin labeling, scanning electron microscopy and semi-thin section analysis. Results showed that hair cell degeneration and hair cell death occurred in a time dependent gradient from base to apex. After 48 h of neomycin treatment, most apical hair cells survived while most basal hair cells died. Calcein labeling provides a sensitive functional assay for measuring hair cell survival.

Animals↗

PubMedDate not supplied

Tailchaser (Tlc): a new mouse mutation affecting hair bundle differentiation and hair cell survival.

We have undertaken a phenotypic approach in the mouse to identifying molecules involved in inner ear function by N-ethyl-N-nitrosourea mutagenesis followed by screening for new dominant mutations affecting hearing or balance. The pathology and genetic mapping of the first of these new mutants, tailchaser (Tlc), is described here. Tlc/+ mutants display classic behavioural symptoms of a vestibular dysfunction, including head-shaking and circling. Behavioural testing of ageing mice revealed a gradual deterioration of both hearing and balance function, indicating that the pathology caused by the Tlc mutation is progressive, similar to many dominant nonsyndromic deafnesses in humans. Based on scanning electron microscopy (SEM) studies, Tlc clearly plays a developmental role in the hair cells of the cochlea since the stereocilia bundles fail to form the characteristic V-shape pattern around the time of birth. By young adult stages, Tlc/+ outer hair bundles are grossly disorganised although inner hair bundles appear relatively normal by SEM. Increased compound action potential thresholds revealed that the Tlc/+ cochlear hair cells were not functioning normally in young adults. Similar to inner hair cells, the hair bundles of the vestibular hair cells also do not appear grossly disordered. However, all types of hair cells in the Tlc/+ inner ear eventually degenerate, apparently regardless of the degree of organisation of their hair bundles. We have mapped the Tlc mutation to a 12 cM region of chromosome 2, between D2Mit164 and D2Mit423. Based on the mode of inheritance and map location, Tlc appears to be a novel mouse mutation affecting both hair cell survival and stereocilia bundle development.

Animals↗

PubMed1999

The fate of hair follicle melanocytes during the hair growth cycle.

The fate of the follicular pigmentary unit during the hair growth cycle has long been one of the great enigmas of both hair follicle and pigment cell biology. Although melanocytes are distributed in several different compartments of the anagen hair follicle, melanogenically active cells are located only in the hair bulb, where they are directly involved in hair shaft pigmentation. These pigment cells are readily detectable only when they become melanogenically active during anagen III of the hair growth cycle. Thus, their status during hair follicle regression (catagen), when melanogenesis is switched off, until they re-appear again as pigment-producing cells in the anagen III hair follicle, has remained poorly defined. Historically, it has been proposed that hair bulb melanocytes adopt a self-perpetuating, catagen-resistant strategy of de-differentiation during hair follicle regression and re-differentiation upon entry into a new anagen phase; however, this explanation remains problematic in the absence of evidence for de-differentiation/re-differentiation plasticity in most nonmalignant cell systems.

Animals↗

PubMed1971

Proteins of normal hair and of cystine-deficient hair from mentally retarded siblings.

1. S-Carboxymethylkerateines extracted from normal hair can be fractionated into high-sulphur and low-sulphur proteins similar to those obtained from sheep's wool. Normal human hair gives a major high-sulphur protein of higher molecular weight and S-carboxymethylcysteine content than any isolated from normal sheep's wool. 2. The proteins from cystine-deficient hair can also be divided into high-sulphur and low-sulphur proteins. There is a lower proportion of high-sulphur protein in cystine-deficient hair than in normal hair. 3. The high-sulphur proteins from cystine-deficient hair have an abnormal amino acid composition and in particular are lower in S-carboxymethylcysteine content than the corresponding proteins from normal hair. New components are present and the content of very high-sulphur proteins of high molecular weight is much decreased. The low-sulphur proteins of cystine-deficient hair are probably also deficient in S-carboxymethylcysteine. 4. The proteins of cystine-deficient hair probably resemble those in the normal hair root, except that disulphide-bridge formation has occurred.

Acrylates↗

PubMed2002

Changes in hair weight and hair count in men with androgenetic alopecia after treatment with finasteride, 1 mg, daily.

BACKGROUND: Finasteride, a type II 5alpha-reductase inhibitor, reduces scalp and serum dihydrotestosterone and has been shown to be effective in men with androgenetic alopecia (AGA). OBJECTIVE: The purpose of this study was to determine the effect of finasteride on scalp hair weight in men with AGA. METHODS: Sixty-six men with AGA received finasteride, 1 mg/d, or placebo in a 48-week study, and 49 men continued in a 48-week extension. Efficacy was assessed by scalp hair weights and hair counts. RESULTS: As expected, hair counts improved with finasteride (net mean percent change +/- SE [95% CI] compared with placebo = 9.2% +/- 2.8% [3.8, 14.6] and 15.4% +/- 3.2% [9.1, 21.7] at 48 and 96 weeks, respectively; P <.01 for both time points), and net improvements in hair weight were greater (25.6% +/- 3.6% [18.5, 32.7] and 35.8% +/- 4.6% [26.7, 44.8] at 48 and 96 weeks, respectively; P <.001 for both time points). Finasteride was generally well tolerated. CONCLUSION: In this study, finasteride, 1 mg, increased hair weight in men with AGA. Hair weight increased to a larger extent than hair count, implying that factors other than the number of hairs, such as increased growth rate (length) and thickness of hairs, contribute to the beneficial effects of finasteride in treated men.

5-alpha Reductase Inhibitors↗

PubMedDate not supplied

Hair analysis for drugs of abuse XII. Determination of PCP and its major metabolites, PCHP and PPC, in rat hair after administration of PCP.

We developed an analytical method for the simultaneous detection of phencyclidine (PCP) and its metabolites, 4-phenyl-4-piperidinocyclohexanol (PPC) and 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (PCHP), in rat hair. Three pigmented, hairy rats were intraperitoneally administered PCP hydrochloride (HCl) at 0.05-0.5 mg/kg once a day for 10 successive days. Animal hair was shaved just before the first administration, and the newly grown hair was collected 4 weeks after the first administration. After the rat hair sample was washed three times with 0.1% sodium dodecyl sulfonate and water, separately, and dried in a desiccator, 20 mg of finely cut hair was extracted with 2 mL methanol-5N HCl (20:1) under ultrasonication for 1 h, followed by storage at room temperature for 14 h. Following filtration and evaporation of the extract, it was purified with Bond Elut Certify in the usual manner, and the extract was derivatized with N,O-bis(trimethylsilyl) acetamide for gas chromatographic-mass spectrometric analysis using deuterated PCP, PPC, and PCHP as internal standards. The selected ions were monitored at m/z 186, 200, and 242 for PCP, m/z 172, 288, and 331 for trimethylsilyl (TMS) PCHP, and m/z 200, 254, and 331 for TMS PPC. PCP, PCHP, and PPC were simultaneously detected in the rat hair down to 0.1 mg/kg PCP HCl. Even at the dose of 0.05 mg/kg, PCP was clearly detected in the rat hair. Based on the area under the concentration versus time curve (AUC) in plasma (1460 ng.min/mL), the PCP concentration (3.34 ng/mg) in the rat hair was quite high. The incorporation rates into hair (concentration in hair/AUC) of PCP, PCHP, and trans-PPC were 2.29, 1.65, and 0.50, respectively, at 0.5 mg/kg. Our results suggest that hair could be a useful specimen for confirmation of active past PCP use because PCP and its metabolites can be detected simultaneously.

Animals↗

PubMed1984

Distribution of epidermal growth factor receptors in rat tissues during embryonic skin development, hair formation, and the adult hair growth cycle.

In a previous study on neonatal rat skin (Green MR, Basketter DA, Couchman JR, Rees DA: Dev Biol 100:506-512, 1983) a close positive correlation was found between epidermal growth factor (EGF) receptor tissue distribution and areas of potential epithelial cell proliferation. We now report on the binding distribution of [125I]EGF, representing the tissue localization of available EGF receptors, during embryonic rat skin development including hair follicle formation and the adult hair growth cycle. At 16 days embryonic development a relatively low receptor density is seen over all the epidermal cell layers but by 17 days, with the onset of very rapid epidermal proliferation, labeling increases and becomes restricted to the basal epidermal cells. Between 17 and 20 days embryonic development, available receptors for EGF are consistently absent from epidermal basal cells overlaying the dermal condensates marking the first stage of hair follicle development. This restricted and temporary loss of EGF receptors above these specialized mesenchymal condensates implies a role for the EGF receptor and possibly EGF or an EGF-like ligand in stimulating the epithelial downgrowth required for hair follicle development. In the anagen hair bulb, receptors for EGF are detected over the outer root sheath and the epithelial cell layers at the base of the follicle and show a correlation with the areas of epithelial proliferation in the hair bulb. During the catagen and telogen phases of the hair cycle, receptors are observed in high numbers on all the undifferentiated or dedifferentiating cells of the degenerating epithelial strand and secondary hair germ. Dermal cells are, in general, less heavily labeled than the basal epithelial cells of skin except for the developing striated muscle (panniculus carnosus) in embryonic skin which is more heavily labeled. The data are discussed in terms of a possible role for the EGF receptor and associated EGF or EGF-like ligands in specific areas of epithelial tissue morphogenesis during embryonic skin maturation, hair follicle development, and hair cycling.

Animals↗

PubMed1994

Biphasic effect of 1,25-dihydroxyvitamin D3 on human hair follicle growth and hair fiber production in whole-organ cultures.

We have used a whole-organ culture system to investigate the effects of 1,25(OH)2D3 on human hair follicle growth and hair fiber production. Relatively low concentrations (1-10 nM) of 1,25(OH)2D3 stimulated the cumulative growth of hair follicles and hair fibers, by 52% and 36%, respectively (concentration producing 50% of the maximal response [EC50] values of 0.3 nM). The initial rates of follicle and fiber growth were increased, whereas the respective growth periods were unaffected. At higher concentrations of 1,25(OH)2D3, there was a dose-dependent inhibition of both follicle and fiber growth (IC50 values of 100 nM), in part due to reduction in the growth periods. There was a marked delay between the onset of 1,25(OH)2D-induced hair follicle and hair fiber growth inhibition. Incubation of hair follicles with 100 nM 1,25(OH)2D3 resulted in a rapid, transient inhibition of DNA synthesis (55% inhibition at 24 h), followed by a gradual return to control levels at day 4. Prolonged (> 5 h), incubation in the presence of 100 nM of 1,25 (OH)2D3 was required for follicle growth inhibition to be manifest. Ro 31-7549, a selective inhibitor of protein kinase C, did not prevent 1,25(OH)2D3-induced inhibition of hair follicle growth. These data suggest that 1,25(OH)2D3 may play a physiologic role in maintaining optimal hair follicle activity, and that elevation of 1,25(OH)2D3 may inhibit hair growth in vivo.

Calcitriol↗

PubMed1996

Genomic characterization of the human type I cuticular hair keratin hHa2 and identification of an adjacent novel type I hair keratin gene hHa5.

Hair keratins, a subset of the keratin multigene family expressed in hard keratinizing structures, previously have been thought to comprise four members of each subfamily, designated Ha1-4 (type I) and Hb1-4 (type II), which are differentially expressed in the cuticle and cortex of the hair follicle. This report describes the genomic cloning and sequencing of the human type I cuticular hair keratin hHa2, as well as the identification of a previously unknown human type I hair keratin gene. The 12.5-kilobase pair genomic clone ghkI2.12, obtained by hybridization of a human genomic deoxyribonucleic acid library with a 3'-complementary deoxyribonucleic acid probe of hHa2, as well as the partially overlapping 14.4-kilobase pair genomic clone ghkI2.17, isolated using a 5'-fragment of clone ghkI2.12, allowed the characterization of the entire hHa2 gene. The gene displays the same exon/intron structure as two previously characterized type I mouse and sheep hair/wool keratin genes with strict positional conservation of the six introns in the region coding for the central alpha-helix. At the 5'-extremity of clone ghkI2.17, i.e., approximately 8.0 kilobase pairs upstream of the hHa2 gene and oriented in the same transcriptional direction, lies the gene for a hitherto unknown human type I hair keratin. Clone ghkI2.17 contains partial sequence information for this gene beginning with intron 5 and extending to the end of the gene. Screening of a human scalp complementary deoxyribonucleic acid library with a 3'-fragment of the gene yielded a full length complementary deoxyribonucleic acid clone of the new hair keratin, which in continuation of the current nomenclature for hair keratins was termed hHa5. Remarkably, the hHa5 gene, which contains an additional 7th intron in its 3'-noncoding region, is expressed mainly in supramatricial cells and lowermost cortical cells of the hair bulb and thus constitutes a very early component of hair morphogenesis. Our results confirm the type specific clustering of keratin genes and indicate that the human type I hair keratin subfamily contains more members than previously assumed.

Amino Acid Sequence↗