Hair growth
Topical minoxidil counteracts stress-induced hair growth inhibition in mice.

Arck PC, Handjiski B, Peters EM, Hagen E, Klapp BF, Paus R.

Department of Internal Medicine, Charite, Humboldt University, Berlin, Germany. petra.arck charite.de

Stress has long been suspected as a possible cause of hair loss in various species, even though convincing experimental evidence has not been available. Recently, we have shown in a murine model that sonic stress alters hair growth and cycling in vivo, and have postulated the existence of a 'brain-hair follicle axis' (BHA). In order to study whether a clinically available and widely used topically active hair growth stimulator mitigates stress-triggered hair growth inhibition in this stress model, we have applied a 5% minoxidil solution. Female CBA/J mice were depilated and randomized in to two groups: control (n = 20) and sonic stress (n = 20). These groups were further divided and either treated daily with 5% minoxidil solution or vehicle alone. The stress group was exposed to sonic stress for 24 h starting 14 days after anagen induction by depilation. All mice were sacrificed 16 days after the depilation and assessed by quantitative histomorphometry. Sonic stress significantly increased the number of hair follicles with apoptotic cells and inhibited intrafollicular keratinocyte proliferation. In addition, the number of clusters of perifollicular MHC class II+ cells and degranulated perifollicular mast cells was significantly enhanced in the stressed mice. In accordance with previous findings, all stressed mice showed an advanced hair cycle progression towards catagen. All of these stress-induced hair growth inhibitory changes along the BHA were down-regulated by topical minoxidil application. This encourages one to explore clinically whether topical minoxidil is a safe and effective pharmacologic tool for the management of stress-associated telogen effluvium in humans.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14705798&dopt=Abstract alopecia, hair loss hair growth



Hair growth
Hair growth in human split-thickness skin grafts transplanted onto nude rats: the role of cyclosporin.

Gilhar A, Etzioni A, Krueger GG.

Laboratory for Skin Research, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.

To date, there have been no descriptions of hair growth following transplantation of human split-thickness skin grafts (HSTSG) to congenitally athymic (nude) mice or rats. Recently, we noted hair growth in HSTSG from scalp skin (HSTSG-SS) transplanted onto rats treated with ciclosporin (CS). By definition, HSTSG-SS of 0.4 mm had all the anagen hairs cut from the papillae. Two months after engraftment, there was histological evidence of the formation of new papillae. Density of hair correlated with thickness of HSTSG, i.e. there were more hairs/square centimeter in HSTSG-SS of 1 mm thickness than in those of 0.4 mm thickness. New hairs appeared on an average of 1 cm2/week in HSTSG-SS that were 1 mm thick; by 10 weeks, the mean density was 7.9 hairs/cm2. In the thinner grafts, the density was 3.5 hairs/cm2 (p less than 0.025). The rate of growth in the thicker grafts ranged from 0 to 0.25 mm/day, with an average of 0.1 mm/day. At 10 weeks after grafting, the hairs had a mean length of 4.4 mm in the thicker and 1.7 mm in the thinner grafts (p less than 0.001). The average diameter of the hair shafts was 0.05 mm at the various times tested. These observations identify a previously unrecognized process of hair growth and present an in vivo model to study human hair growth process, including the role of CS in hair growth.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2242778&dopt=Abstract alopecia, hair loss hair growth



Hair growth
Restoration of hair growth in mice with an alopecia areata-like disease using topical anthralin.

Tang L, Cao L, Sundberg JP, Lui H, Shapiro J.

Division of Dermatology, University of British Columbia and Vancouver General Hospital, 828 West 10th Avenue, Vancouver, B.C. V5Z 1E8, Canada. ltang vanhosp.bc.ca

Anthralin is a widely used topical anti-psoriatic drug that may have an immunomodulating effect on alopecia areata (AA) as it does in psoriasis. The aims of the present study were to investigate the effects of anthralin on hair growth in balding C3H/HeJ mice affected by an AA-like disease and to study the underlying mechanisms. Affected C3H/HeJ mice were treated daily for 10 weeks on half of the dorsal skin with 0.2% anthralin and the contra-lateral side was treated with the vehicle ointment. The percentage of surface hair coverage and hair density was graded weekly for both sides and hair growth indices were calculated using these two variables. Hair regrowth was observed in 9/14 mice on the treated sides. Four mice displayed near complete replacement of normal density and length hairs. All the vehicle-treated sides showed either no change or continued hair loss. An RNase protection assay (RPA) showed that expression of tumor necrosis factor-alpha (TNF-alpha) and -beta were inhibited by anthralin upon successful treatment. It appears that anthralin may be an effective therapy for C3H/HeJ mice with AA and certain cytokines may be involved in the therapeutic effects of anthralin on restoring hair regrowth in AA-affected C3H/HeJ mice.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15009110&dopt=Abstract alopecia, hair loss hair growth



Hair growth
[Effects of the extract from bergamot and boxthorn on the delay of skin aging and hair growth in mice]

[Article in Chinese]

Shao LX.

College of Life and Environment Science, Zhejiang Normal University, Jinhua 321004, Zhejiang, China. shaolinxiang sina.com

OBJECTIVE: To study the effects of the extract from bergamot and boxthorn on the skin and the hair growth in mice. METHOD: The skin on the back of mice was shaved topically and smeared with bergamot and boxthorn extract for 42 days. Then the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) and collagen in the mice were measured. The growth of hair was also observed. RESULT: Compared with control group, the extract from bergamot and boxthorn obviously increased the activity of superoxide dismutase (P < 0.05) and the content of collagen (P < 0.001), and decreased the content of malondialdehyde (P < 0.05) in the skin of mice. It also significantly promoted the growth of hair (P < 0.001). CONCLUSION: The extract from bergamot and boxthorn plays an active role in skin and the promotion of hair growth.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15015364&dopt=Abstract alopecia, hair loss hair growth



Hair growth
Differences in activity of minoxidil and cyclosporin A on hair growth in nude and normal mice. Comparisons of in vivo and in vitro studies.

Buhl AE, Waldon DJ, Miller BF, Brunden MN.

Hairgrowth Research and Biostatistics, Upjohn Company, Kalamazoo, Michigan.

Hair growth effects of minoxidil and cyclosporin A were assessed in a series of experiments using nude mice. Systematic monitoring of coat hair showed that untreated nude mice grow extremely sparse and transient hair in cycles. This monitoring was done by photographing each animal through at least one full growth cycle and rating peak growth on a 1 to 4 scale. Topical administration of minoxidil or minoxidil sulfate did not influence this cyclic hair growth. Orally administered minoxidil also had no effect but oral cyclosporin A increased peak hair growth. None of the treatments altered the length of the hair cycle. Direct drug effects on follicles were tested in vitro using organ cultured vibrissae from both nude and normal mice. Minoxidil stimulated hair growth in follicles from normal but not nude mice. In contrast, cyclosporin A stimulated growth only in vibrissae follicles from nude but not normal animals. These studies show that minoxidil and cyclosporin A influence hair growth differentially. Cyclosporin A directly affects nude hair follicles by apparently compensating for a genetic defect inherent in nude follicles. Minoxidil does not have a similar effect. Apparently, the biochemical pathway activated by minoxidil is not a critical defect of hair growth in nude mice. We conclude that nude mice are not useful for studying minoxidil effects but they may be useful in studying pleiotropic effects of the nude gene on hair growth.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2296155&dopt=Abstract alopecia, hair loss hair growth



Hair growth
Effect of constant-release melatonin implants and prolonged exposure to a long day photoperiod on prolactin secretion and hair growth in mouflon (Ovis gmelini musimon).

Santiago-Moreno J, Lopez-Sebastian A, del Campo A, Gonzalez-Bulnes A, Picazo R, Gomez-Brunet A.

Departamento Reproduccion Animal, Centro de Investigacion y Tecnologia y Conservacion de Recursos Zoogenet., SGIT-INIA, Avda. Puerta de Hierro km 5,9, 28040 Madrid, Spain. moreno inia.es

The aims of this study were to examine whether mouflons exposed to constant long and short day photoperiods are able to exhibit an annual cycle of hair growth and moult, and prolactin (PRL) secretion. Mouflon ewes were assigned to three groups of treatment. Ewes were maintained, either under natural photoperiod (control, n = 9), or received a series of subcutaneous melatonin implants from December to April (n = 8), or were exposed to a constant long day photoperiod (16-h light:8-h dark; 16L:8D) during 18 months (n = 7). Blood was collected weekly to determine PRL concentrations, and hair samples were clipped weekly from the base of the neck to measure the length of predominant hair. Under constant long days and with melatonin implants, mouflons expressed an annual rhythm of PRL secretion, even though these treatments modified the times of rise or falling of PRL concentrations throughout the year. Hair growth initiation was almost coincident with the summer solstice in both control and melatonin-implanted mouflons but occurred two months earlier in long day hold mouflons (P < 0.001). Long day hold mouflons had a lower hair growth rate than control and melatonin-implanted mouflons (P < 0.001), and at the end of the experiment, a shorter hair length (3.4 +/- 0.24 cm; P < 0.01) than control (4.3 +/- 0.17 cm), and melatonin-implanted mouflons (4.2 +/- 0.12 cm). Our data support the conclusion that in mouflon, an endogenous circannual rhythm of PRL secretion exists, and that the seasonal cycle of hair growth and moult appears to depend, at least in part, on circulating levels of PRL.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15063923&dopt=Abstract alopecia, hair loss hair growth