Lightening Effect on Ultraviolet-Induced Pigmentation of Guinea Pig Skin by Oral Administration of a Proanthocyanidin-Rich Extract from Grape Seeds

Antioxidants such as vitamins C and E have been reported to inhibit the progression of ultraviolet (UV) radiation-induced pigmentation in the skin of hairless mice. However, little is known of the lightening effect of proanthocyanidin, a powerful polyphenolic antioxidant, on UV-induced pigmentation of the skin. We investigated the lightening effect of oral administration of a proanthocyanidin-rich grape seed extract (GSE) using guinea pigs with UV-induced pigmentation. These pigmented guinea pigs were fed diets containing 1% GSE or 1% vitamin C (w/w) for 8 weeks. GSE-feeding had an apparent lightening effect on the guinea pigs' pigmented skin. Histologic evaluation demonstrated a decrease in the number of 3,4-dihydroxyphenylalanine (DOPA)-positive melanocytes as well as 8-hydroxy-2'-deoxyguanosine (8-OHdG)-positive, Ki-67-positive, proliferating cell nuclear antigen (PCNA)-positive melanin-containing cells in the basal epidermal layer of the UV-irradiated skin in GSE-fed guinea pigs. In contrast, these parameters did not change in the skin of vitamin C-fed or control guinea pigs. GSE inhibited the activity of mushroom tyrosinase and also inhibited melanogenesis without inhibiting the growth of cultured B16 mouse melanoma cells. In conclusion, we demonstrated that oral administration of GSE is effective in lightening the UV-induced pigmentation of guinea pig skin. This effect may be related to the inhibition of melanin synthesis by tyrosinase in melanocytes and the reactive oxygen species (ROS)-related proliferation of melanocytes.

Effects of a melanogenic bicyclic monoterpene diol on cell cycle, p53, TNF-alpha, and PGE2 are distinct from those of UVB

PURPOSE

Bicyclic monoterpene (BMT) diols are small-molecule compounds that mimic ultraviolet radiation (UVR) by inducing melanogenesis. The objective of this study was to compare the effects of 2,2-dimethyl-3-propanyldiol-norbornane (AGI-1140), a novel BMT diol, and ultraviolet B (UVB) on additional cellular responses.

METHODS

S91 mouse melanoma cells were treated with a range of concentrations of AGI-1140, and examined for induction of melanogenesis and nitric oxide (NO). The effect of AGI-1140 on dendrite outgrowth from human melanocytes was examined by quantitative microscopy. The effect of AGI-1140 and UVB on phosphorylation of p53 serine 15 in human keratinocytes was examined by Western blotting, while the release of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2) was determined by enzyme-linked immunosorbent assay. The effects of AGI-1140 and UVB on cell cycle arrest of human melanocytes, keratinocytes, fibroblasts, and endothelial cells were compared using fluorescence-activated cell sorting.

RESULTS

Similar to UVB, AGI-1140 induced both melanogenesis and NO in melanoma cells. AGI-1140 also induced dendrite outgrowth from melanocytes, indicative of differentiation. However, whereas UVB induced G2 cell cycle arrest with phosphorylation of p53 at serine 15, AGI-1140 induced G1 cell cycle arrest without this phosphorylation. Additionally, unlike UVB, AGI-1140 did not increase the secretion of TNF-alpha or PGE2, mediators of UVB-induced immunosuppressive and inflammatory responses in the skin that may contribute to carcinogenesis.

CONCLUSION

This study shows that melanogenesis can be induced by AGI-1140 without many of the deleterious effects associated with UVB.

Enhancement of the depigmenting effect of hydroquinone and 4-hydroxyanisole by all-trans-retinoic acid (tretinoin): the impairment of glutathione-dependent cytoprotection?

Many of the well-known depigmenting agents such as hydroquinone and 4-hydroxyanisole are, in fact, melanocytotoxic chemicals which are oxidized in melanocytes to produce highly toxic compounds such as quinones. These cytotoxic compounds are responsible for the destruction of pigment cells, which results in skin depigmentation. However, cells are capable of protecting themselves against cytotoxic agents by intracellular glutathione (GSH). This protection takes place under the enzymatic action of the detoxification enzyme glutathione S-transferase (GST), which is responsible for the conjugation of toxic species to GSH. The depigmenting effect of hydroquinone is shown to be potentiated by buthionine sulfoximine (BSO) and cystamine as the result of the reduction of intracellular levels of GSH by these two agents. Additionally, BSO and cystamine are shown to inhibit the activity of GST. The combination of all-trans-retinoic acid (tretinoin, TRA) with hydroquinone or 4-hydroxyanisole is also known to produce synergetic skin depigmentation. TRA serves as a potent inhibitor of mammalian GSTs and is known to make cells more susceptible to the cytotoxic effect of chemicals by inhibiting the activity of this enzyme. This agent is also shown to reduce the level of intracellular GSH in certain cells. We have proposed that the mechanism of action of TRA to synergistically enhance the melanocytotoxic effect of chemicals involves the inhibition of GST and the impairment of glutathione-dependent cytoprotection against melanocytotoxic agents.

Molecular responses to photogenotoxic stress induced by the antibiotic lomefloxacin in human skin cells: from DNA damage to apoptosis

Photo-unstable chemicals sometimes behave as phototoxins in skin, inducing untoward clinical side-effects when exposed to sunlight. Some drugs, such as psoralens or fluoroquinolones, can damage genomic DNA, thus increasing the risk of photocarcinogenesis. Here, lomefloxacin, an antibiotic from the fluoroquinolone family known to be involved in skin tumor development in photoexposed mice, was studied using normal human skin cells in culture: fibroblasts, keratinocytes, and Caucasian melanocytes. When treated cells were exposed to simulated solar ultraviolet A (320-400 nm), lomefloxacin induced damage such as strand breaks and pyrimidine dimers in genomic DNA. Lomefloxacin also triggered various stress responses: heme-oxygenase-1 expression in fibroblasts, changes in p53 status as shown by the accumulation of p53 and p21 proteins or the induction of MDM2 and GADD45 genes, and stimulation of melanogenesis by increasing the tyrosinase activity in melanocytes. Lomefloxacin could also lead to apoptosis in keratinocytes exposed to ultraviolet A: caspase-3 was activated and FAS-L gene was induced. Moreover, keratinocytes were shown to be the most sensitive cell type to lomefloxacin phototoxic effects, in spite of the well-established effectiveness of their antioxidant equipment. These data show that the phototoxicity of a given drug can be driven by different mechanisms and that its biologic impact varies according to cell type.

Effects of topical L-selenomethionine with topical and oral vitamin E on pigmentation and skin cancer induced by ultraviolet irradiation in Skh:2 hairless mice

BACKGROUND

The antioxidants selenium and vitamin E can be effective in reducing acute and chronic ultraviolet (UV)-induced skin damage.

OBJECTIVE

This study investigated whether topical L-selenomethionine with topical RRR-alpha-tocopherol (Eol) or oral RRR-alpha-tocopheryl acetate (Eac) can reduce the incidence of UV-induced skin damage more than treatment with each alone.

METHODS

Skh:2 hairless pigmented mice were treated with lotion vehicle, L-selenomethionine lotion, Eol lotion, oral Eac, L-selenomethionine plus Eol lotion, or L-selenomethionine lotion plus oral Eac and exposed to UVB. Skin pigmentation was scored, and the number of skin tumors per animal was counted weekly.

RESULTS

Mice treated with selenium and vitamin E had significantly less acute and chronic UV-induced skin damage.

CONCLUSION

Topical L-selenomethionine alone and combined with vitamin E gave the best protection against UV-induced blistering and pigmentation. In protecting against skin cancer, topical Eol and topical L-selenomethionine plus oral Eac were best. Significant synergy of L-selenomethionine with vitamin E was not observed.

Factors influencing sunless tanning with dihydroxyacetone

BACKGROUND

Sunless tanning preparations have been used for more than 50 years and are still very popular because they provide temporary pigmentation resembling an ultraviolet-induced tan. The pigment is the product of reactions between dihydroxyacetone (DHA) and amino acids in the stratum corneum.

OBJECTIVES

To understand the factors that influence the reactions of DHA with amino acids in the stratum corneum with the ultimate goal of producing pigmentation with greater photoprotection.

METHODS

The influence of hydration and/or oxygen on the development of DHA-induced pigment was assessed in vivo using an occlusive dressing and ex vitro on human epidermal preparations. Two spectroscopic techniques, diffuse reflectance and fluorescence emission, were used to monitor the extent of pigment development. The optimal relative humidity for DHA-induced pigmentation was assessed on the epidermal preparations. The formation of products from reactions between DHA and nine amino acids was studied in solutions buffered at pH 5 and 7.

RESULTS

Development of DHA-induced pigmentation was inhibited by a 24-h occlusive dressing but appeared after its removal, indicating that DHA was still present. High hydration but not the absence of oxygen inhibited coloration of occluded skin. The extent of pigmentation did not vary in a simple manner with hydration, as pigment formation was positively correlated with humidity from 0 to 75% but negatively correlated from 75 to 100%. Lysine, glycine and histidine reacted most rapidly with DHA, with reaction rates greater at pH 7 than at pH 5. The products absorbed with maxima at wavelengths up to 340 nm.

CONCLUSIONS

These results indicate that extent of hydration, pH and availability of certain amino acids influence the development of DHA-induced pigmentation in the stratum corneum and suggest that manipulation of these factors might produce pigmentation with greater photoprotection.

Stress augmented ultraviolet-irradiation-induced pigmentation

It was reported that adrenocorticotropic hormone stimulates melanogenesis in cultured melanocytes. Stress (high population density and restraint stress) induced a significant increase in adrenocorticotropic hormone levels in plasma and skin compared to control. The serum obtained from HR-1 x HR/De F1 female mice subjected to stress showed significantly increased tyrosinase activity in human melanocytes compared to that from nonstressed mice. The increase in tyrosinase activity was inhibited in the presence of 10 nM corticostatin, an adrenocorticotropic hormone inhibitor. The aim of this study was to examine whether adrenocorticotropic hormone released into the circulation under stressful conditions is associated with the regulation of ultraviolet-induced pigmentation. Mice divided into three groups were housed for 22 d under the following conditions: five mice per cage (control); 10 mice per cage (high population density); restraint stress 4 h per d. The animals were exposed to ultraviolet-B irradiation (72 mJ per cm2, thrice per wk). After ultraviolet-B irradiation, delayed tanning was marked in stressed mice. The number of dihydroxyphenylalanine-positive melanocytes also significantly increased in stressed animals. Pretreatment with 100 microg of corticostatin inhibited the augmentation of the stress-induced pigmentary response and the increase in dihydroxyphenylalanine-positive melanocytes after ultraviolet irradiation. Adrenocorticotropic hormone released by stress may activate tyrosinase in melanocytes, resulting in the augmentation of ultraviolet-induced pigmentation. These results suggest that adrenocorticotropic hormone is at least partly responsible for the sensitivity of the pigmentary response after ultraviolet irradiation under stressful conditions.

Effectiveness of oral Ginkgo biloba in treating limited, slowly spreading vitiligo

For effective treatment of vitiligo, it is as important to arrest the progression of the disease as it is to induce repigmentation. Recently, oxidative stress has been shown to play an important role in the pathogenesis of vitiligo. Ginkgo biloba extract has been shown to have antioxidant and immunomodulatory properties. In a double-blind placebo-controlled trial, we evaluated the efficacy of G. biloba extract in controlling the activity of the disease process in patients with limited and slow-spreading vitiligo and in inducing repigmentation of vitiliginous areas. Fifty-two patients were assigned to two treatment groups (A and B) in a double-blind fashion, but only 47 patients could be evaluated, because one patient in group A and four patients in group B withdrew for reasons unrelated to the study. Patients in group A were given G. biloba extract 40 mg three times daily whereas patients in group B received placebo in similar doses. A statistically significant cessation of active progression of depigmentation was noted in patients treated with G. biloba (P = 0.006). Marked to complete repigmentation was seen in 10 patients in group A, whereas only two patients in group B showed similar repigmentation. The G. biloba extract was well tolerated. G. biloba extract seems to be a simple, safe and fairly effective therapy for arresting the progression of the disease.

Increased periocular pigmentation with ocular hypotensive lipid use in African Americans

PURPOSE

To report increased eyelid pigmentation as an adverse side effect associated with topical ocular hypotensive lipids in African Americans.

DESIGN

Interventional case series.

METHODS

Two African-American patients with open-angle glaucoma are described in whom increased eyelid pigmentation developed 1 month to 5 months after beginning treatment with either latanoprost or bimatoprost.

RESULTS

Latanoprost was discontinued in an African-American patient, and pigmentation gradually diminished by 3 months after cessation of latanoprost. Increased eyelid pigmentation and increased eyelash length were noted in another African-American patient after just 4 weeks on bimatoprost.

CONCLUSIONS

An increase in eyelid pigmentation and eyelash growth is a possible complication of topical ocular hypotensive lipid therapy, even in African-American patients. The changes seems to present earlier after bimatoprost treatment then after latanoprost treatment. Cessation of these medications may lead to loss of induced pigmentation.

[Cyclines and acne: pay attention to adverse drug reactions! A recent literature review]

PURPOSE

Cyclines are broad-spectrum antibiotics often used in acne. Side effects might occur precociously or more insidiously during long term treatment such in acne. The aim of this study is to review all adverse effects recently reported in this indication.

CURRENT KNOWLEDGE AND KEY POINTS

A literature review from 1997 to 2001 has been conducted. Seventy-six articles reporting 250 cases have been found. Data analysis indicated that minocycline is the most widely incriminated molecule. Seventy-two cases revealed autoimmune disorders : lupus like syndrome associated or not with autoimmune hepatitis, 5 cases developed vasculitis. These reactions occurred in long term treatment (several weeks to several months). Fifteen cases of hypersensitivity syndromes and 3 cases of serum sickness like illness have been reported. These reactions occurred within the first weeks of exposure. Twenty-four cases of pseudotumor cerebri and 123 cases of abnormal pigmentations (skin, nails, mouth, bones or organs) have also been found. Eight cases presented other diseases.

FUTURE PROSPECTS AND PROJECTS

Adverse effects of cyclines might be serious and sometimes unknown. Long term treatment by tetracyclines must be researched in patients presenting such symptoms. Moreover, several adverse drug reactions might be avoided by an optimal use of the drug (oesophageal ulcerations, photosensitivity) or by shorter periods of treatment (autoimmune disorders, pigmentations); only DRESS are drug adverse reactions unpredictable and sometimes severe.

Influence of hydration on dihydroxyacetone-induced pigmentation of stratum corneum

Dihydroxyacetone, the browning ingredient in sunless tanning formulations, reacts with amino acids in the outer stratum corneum to form a mixture of high molecular weight pigments. Our initial observations indicated that high hydration of dihydroxyacetone-treated skin completely inhibited development of pigmentation. To investigate the mechanism underlying this effect, studies were carried out in isolated murine epidermis, polyvinyl alcohol/lysine films, and lysine in glycerol/water solvent. Murine epidermis treated with dihydroxyacetone showed a biphasic dependence on relative humidity: maximum pigmentation developed at 84% relative humidity and minimum pigmentation at 0% and 100% relative humidity. Filaggrin proteolysis, which shows a similar dependence on relative humidity and provides free amino acids in the outer stratum corneum, did not account for the relative humidity dependence of dihydroxyacetone pigmentation. A similar biphasic pigmentation response was obtained when polyvinyl alcohol film containing lysine was treated with dihydroxyacetone and incubated at various relative humidities, indicating that the structure of the stratum corneum was not a major factor. To remove the influence of the matrix, the reaction of dihydroxyacetone with lysine was followed at varying concentrations of water in mixed glycerol/buffer solvent. Again, greater pigment formation was found at an intermediate level of water (6% vol/vol) and little pigmentation at 0% and 100% water content. These results are consistent with a requirement for water at low relative humidity, which facilitates formation of free amine groups needed for the initial reaction with dihydroxyacetone, and with inhibition of the dehydration reactions by water through the law of mass action at high relative humidity.

Co-culture of mouse epidermal cells for studies of pigmentation

Interactions between melanocytes and keratinocytes in the skin suggest bi-directional interchanges between these two cell types. Thus, melanocytes cultured alone may not accurately reflect the physiology of the skin and the effects of physiological regulators in vivo, because they do not consider possible interactions with keratinocytes. As more and more pigment genes are identified and cloned, the characterization of their functions becomes more of a challenge, particularly with respect to their roles in the processing and transport of melanosomes and their transfer to keratinocytes. Immortalized melanocytes mutant at these loci are now being routinely generated from mice, but interestingly, successful co-culture of murine melanocytes and keratinocytes is very difficult compared with their human counterparts. Thus, we have now optimized co-culture conditions for murine melanocytes and keratinocytes so that pigmentation and the effects of specific mutations can be studied in a more physiologically relevant context.

Tacrolimus ointment 0.1% produces repigmentation in patients with vitiligo: results of a prospective patient series

The cause of the selective melanocyte destruction in vitiligo may be due to an autoimmune disorder. A series of 15 patients with vitiligo were treated with a topical immunomodulator, tacrolimus ointment 0.1%, twice daily for a minimum of 45 days. Thirteen patients (87%) experienced at least partial repigmentation, and 3 of those patients had greater than 75% repigmentation. Patients with the greatest treatment response likely benefited from concomitant natural sunlight exposure. Further studies investigating the safety and efficacy of tacrolimus ointment either as monotherapy or in combination with other therapeutic measures are warranted.

Development of 5-[(3-aminopropyl)phosphinooxy]-2-(hydroxymethyl)-4H-pyran-4-one as a novel whitening agent

A stable derivative of kojic acid, 5-[(3-aminopropyl)phosphinooxy]-2-(hydroxymethyl)-4H-pyran-4-one (Kojyl-APPA), was synthesized in good yield. The effects of Kojyl-APPA on tyrosinase activity and melanin synthesis were investigated. Kojyl-APPA showed tyrosinase inhibition effect (30%) in situ, but not in vitro. Kojyl-APPA inhibited tyrosinase activity significantly at 24 h after treatment in normal human melanocytes. It means that Kojyl-APPA is not a direct inhibitor of tyrosinase itself, but it is converted to a potential inhibitor kojic acid enzymatically in cells. In addition, Kojyl-APPA decreased melanin content to 75% of control in melanoma cells and decreased neomelanin synthesis to 43% of control in normal human melanocytes. Its permeation through skin increased by about 8 times as compared with kojic acid.

Topical glycolic acid enhances photodamage by ultraviolet light

BACKGROUND

Alpha-hydroxy acids (AHAs) are widely used as ingredients in cosmetics. Several studies suggest that AHAs can increase the sensitivity of skin to ultraviolet (UV) light.

PURPOSE

This study was performed in order to determine whether short-term dermal treatment with glycolic acid, a representative AHA, can enhance the damaging effects of UV light. The duration of the effect of AHAs on the sensitivity of skin to UV light was also examined.

METHODS

The backs of 29 Caucasian subjects were treated, once daily, 6 days per week with either 10% glycolic acid (pH 3.5) or placebo in a randomized double-blinded study. At the end of 4 weeks, sites within each treated area were exposed to 1.5 MED of UV light, determined on previously untreated skin. Specimens were obtained for enumeration of sunburn cells (SBCs) in the first group of subjects (n = 16), whereas cyclobutyl pyrimidine dimers (CPDs) in DNA were determined in the second group (n = 13). The minimal erythema dose (MED) in each site was also determined in the first group of subjects. Sunburn cells and MEDs were re-evaluated in the first group 1 week after discontinuing AHA applications.

RESULTS

Glycolic acid caused enhanced sensitivity to UV light measured as increased SBC induction and lowered MEDs. Cyclobutyl pyrimidine dimers were elevated but not to a statistically significant level. No differences in SBCs or MEDs were evident after a week of discontinued treatments.

CONCLUSION

Short-term application of 10% glycolic acid sensitizes the skin to the damaging effects of UV light. This photosensitivity is reversed within a week of terminating treatments.

[Cosmetic use of skin depigmentation products in Africa]

The use of skin lightening products represents a real social phenomenon in many Sub-Saharan African countries. A few studies have been published on this subjects. An important proportion of the adult female population, estimated between 25 and 67% uses regularly and daily these creams. Today the products used are mainly dermocorticosteroids and hydroquinone. Their use over a long period of time is responsible for many cutaneous side effects mainly acne, pigmentary disorders, stretch marks and cutaneous infections. Systemic side effects have recently been reported, mainly related to the use of corticosteroids. The necessary control of the products by the local health authorities remains difficult.

Depigmenting action of phenylhydroquinone, an O-phenylphenol metabolite, on the skin of JY-4 black guinea-pigs

The effects of o-phenylphenol (OPP) and its metabolite, phenylhydroquinone (PHQ) on the skin of JY-4 black guinea-pigs were studied. Topical application of 1 or 5% PHQ on the black skin of the back caused marked depigmentation and hypopigmentation of the skin after 5 weeks, whereas OPP applied at the same concentrations had little effect. Depigmented skin had an increased L* (lightness) value in the CIE-L*a*b* color system. This corresponded with a decreased number of melanocytes and melanosomes in the melanocytes and keratinocytes, the disruption of melanosomes in the melanocytes, and destruction of the membranous organelles of the melanocytes. These morphological and numerical changes in epidermal melanocytes indicate that selective melanocyte toxicity occurred. Furthermore, application of PHQ to the skin of white guinea-pigs caused skin irritation, as shown by a colorimetric increase in a* value (redness) and by histological observation of inflammation. This study confirmed that OPP, which is a reported depigmenter, has little depigmenting action, while its metabolite, PHQ, is a potent depigmenter preferentially affecting melanocytes.

Topical prostaglandin analog (PGE2) in vitiligo--a preliminary study

BACKGROUND

Several therapeutic options are available for the treatment of vitiligo, but none is uniformly effective. Prostaglandin has been shown to play a role in melanocyte proliferation and melanogenesis. Topical application of prostaglandin E2 (PGE2) over mice skin has been shown to increase melanocyte density.

AIM

To evaluate the role of topical PGE2 in the treatment of vitiligo.

METHODS

We enrolled 27 patients with limited vitiligo lesions in this study. Patients were instructed to apply a translucent gel containing 0.5 mg/3 g (166.6 micro g/g) PGE2 to depigmented skin.

RESULTS

Twenty-four patients were evaluated at the end of 6 months, as three patients withdrew for reasons unrelated to the study. At the end of treatment, 15 patients showed marked to complete repigmentation and three patients showed moderate repigmentation. The remaining six patients showed none to minimal repigmentation.

CONCLUSIONS

Marginal repigmentation with hyperpigmented borders was seen in the majority of lesions. Our results are encouraging and offer a new and potentially efficacious treatment for this pigmentation disorder.

Modulation of microphthalmia-associated transcription factor gene expression alters skin pigmentation

The microphthalmia-associated transcription factor is implicated in melanocyte development and in the regulation of melanogenesis. Microphthalmia-associated transcription factor is thought to bind to the M-box promoter elements of tyrosinase, tyrosinase-related protein-1 and dopachrome tautomerase/tyrosinase-related protein-2 and transactivate these genes, resulting in increased pigmentation. Using a luciferase reporter construct driven by the microphthalmia-associated transcription factor promoter, we identified agents that modulate microphthalmia-associated transcription factor promoter activity. Changes in endogenous microphthalmia-associated transcription factor expression levels upon treatment with these agents were confirmed using northern and western blots, and their pigmentary modulating activities were demonstrated. Ultraviolet B irradiation and traditional Chinese medicine-1, a natural extract used in traditional Chinese medicine, upregulated microphthalmia-associated transcription factor gene expression and enhanced tyrosinase activity in vitro. Dihydrolipoic acid, lipoic acid, and resveratrol reduced microphthalmia-associated transcription factor and tyrosinase promoter activities. These agents also inhibited the forskolin- and ultraviolet B-stimulated promoter activities of these genes and significantly reduced tyrosinase activity in melanocyte cultures, resulting in depigmentation. Overexpressed microphthalmia-associated transcription factor was capable of rescuing the repressive effects of these compounds on the cotransfected tyrosinase promoter. Dark-skinned Yucatan swine treated with these agents showed visible skin lightening, which was confirmed histologically, whereas ultraviolet B-induced tanning of light-skinned swine was inhibited using these agents. Our findings suggest that modulation of microphthalmia-associated transcription factor expression can alter skin pigmentation and further confirm the central role of microphthalmia-associated transcription factor in melanogenesis.

A human placental extract: in vivo and in vitro assessments of its melanocyte growth and pigment-inducing activities

BACKGROUND

The authenticity of various prototype human placental extracts with biological activity, such as that inducing vitiligo repigmentation, is under serious criticism, mainly due to a lack of demonstration at the cellular level. Considering the present worldwide scenario with regard to the occurrence and treatment of vitiligo, a thorough scientific exploration of such extracts should be undertaken.

METHOD

One such prototype placental preparation was prepared, and was evaluated with regard to its melanogenic action in C57BL/6J mice in vivo and its mitogenic and melanogenic activity on B16F10 mouse melanoma cells and normal human melanocytes in vitro. The extract was applied topically to mice with age-induced prolonged telogenic phase of hair growth (grey body coat hair). Standard 3H-thymidine incorporation and spectrophotometric methods were followed to illustrate mitogenic and melanogenic effects at the cellular level.

RESULTS

The resurgence of blue skin, followed by shiny black hair, at the regions of application of the extract demonstrated the reversal of the age-induced prolonged telogenic phase of hair growth to the anagenic phase after topical application of the extract on C57BL/6J mice. Further support was obtained from histology where, at the extract-treated sites, the development of new melanogenic centers and hair follicles was observed. During in vitro studies, the vehicle-free extract constituents stimulated both mitogenesis and melanogenesis of B16F10 mouse melanoma cells in a concentration-dependent manner. The cell morphology and extent of melanogenesis also showed significant changes. In addition, two known melanocyte activity-modulating peptides, endothelin-1 (ET-1) and adrenocorticotropic hormone (ACTH), were determined in the extract, chiefly in the total lipid fraction, indicating their effective cutaneous permeation.

CONCLUSIONS

The extract was found to be a potent mitogen in the in vitro condition and a potent melanogen in both the in vitro and in vivo situations. This strongly suggests its therapeutic potential for the repigmentation of vitiligo patches.

Topical tacrolimus for repigmentation of vitiligo

We describe 6 patients with generalized vitiligo who responded to treatment with tacrolimus ointment. Moderate to excellent repigmentation was achieved in 5 patients. Although the number of cases in this noncontrolled, nonblinded series is small, tacrolimus ointment may be an efficacious and safe treatment option for vitiligo.