Anti-oxidant defence mechanism in vitiliginous skin increases with skin type.

BACKGROUND: Vitiligo skin shows different burning capacity in people with different phototype. In normal skin antioxidant status is correlated to skin phototype, but unexpectedly it appears that there is a gradual decrease in burning susceptibility of depigmented skin of individuals with increasing phototype (II→VI). OBJECTIVE: To assess if the antioxidant response in the lesional vitiligo skin is involved in those protection mechanisms. Moreover, a possible correlation between cutaneous and systemic endogenous antioxidants in vitiligo patients has been investigated. METHODS: We enrolled in the study 29 patients with active vitiligo, divided into five groups according to skin type (II to VI). We analysed reduced and oxidized glutathione (GSH and GSSG, respectively), ubiquinone (CoQ10), catalase (Cat), superoxide dismutases (Cu/Zn-SOD and Mn-SOD), GSH peroxidase (GSH-Px), as indexes of chemical and enzymatic antioxidants, in suction blister roofs as well as in peripheral blood mononuclear cells (PBMNCs). RESULTS: The vitiligo patients showed an imbalance of antioxidant network, both in depigmented skin and PBMNCs. Interestingly, in vitiligo skin a phototype-related increase of antioxidant enzyme activities (Cat, Mn-SOD and GPx) and GSH amount have been observed. Similarly in PMBNCs Cat and total SOD activities, as well as GSH content progressively increased from skin type II to skin type VI. Endogenous antioxidants in vitiligo skin are correlated to those in PBMNCs, suggesting that systemic and epidermal antioxidant network functionalities are connected. CONCLUSIONS: The correlation between antioxidant levels and clinical phototype confirmed the hypothesis that other factors than melanin determine largely the minimal erythema dose values in vitiligo lesional skin.

A global survey of the role of ultraviolet radiation and hormonal influences in the development of melasma.

BACKGROUND: It has been generally believed that the four main causes of melasma are pregnancy, hormonal contraception, family history and sun exposure; however, there are few published comprehensive studies that confirm these assertions. The Pigmentary Disorders Academy - an international group of experts in pigmentary disorders - designed and conducted a global survey of women to investigate the effect of these factors on onset and chronicity of melasma and the course of the disease in order to gain a better understanding of the causative factors associated with this disorder, with a particular focus on hormonal factors and UV exposure in females. METHODS: A 40-item largely self-administered questionnaire was completed by 324 women being treated for melasma in nine clinics worldwide. RESULTS: The mean age at onset of melasma was 34 years, and 48% of subjects questioned had a family history of melasma (97% in a first-degree relative). Subjects with family history of melasma tended to have darker skin (90% types III-VI) compared to those without (77% types III-VI). The most common time of onset was after pregnancy (42%), often years after the last pregnancy, with 29% appearing pre-pregnancy and 26% during pregnancy. Onset was related to darker skin type post-pregnancy (P = 0.002). Risk of onset during pregnancy was associated with having spent more time outdoors (an extra 10 h per week spent working outside increases the odds of onset of melasma during pregnancy by approximately 27%) and an increased maternal age at pregnancy (increased by approximately 8% for each year of age at first pregnancy; P = 0.02). The odds of melasma occurring for the first time during a pregnancy were also increased with multiple pregnancies (twice the odds if 2 vs. 1 pregnancies, three times higher if 3 or more vs. 1 pregnancy). Of the women, 25% who had used hormonal contraception claimed that melasma appeared for the first time after its use, the rate being higher for those without vs. with a family history. CONCLUSIONS: The results suggest that, whilst accepted causes do affect onset of melasma, a combination of these factors often triggers this disorder. These factors may provide further insights into how physicians can manage individual melasma cases, support recommendation of preventative measures and even anticipate treatment results and recurrence.

Ultrastructural findings in progressive macular hypomelanosis indicate decreased melanin production.

BACKGROUND: The pathogenesis of progressive macular hypomelanosis (PMH) is unknown. Recently, Westerhof et al. (Arch Dermatol 2004; 140: 210-214) hypothesized that Propionibacterium acnes produces a depigmenting factor that interferes with melanogenesis in the skin, resulting in hypopigmented spots. The purpose of the study is to gain an insight into the pathogenesis of PMH. MATERIALS AND METHODS: We took a biopsy of 2-mm diameter from normal and lesional skin in eight PMH patients. Using electron microscopy, we compared melanization of melanosomes, melanosome transfer and amount of epidermal melanin in normal and lesional skin. RESULT: Compared to non-lesional skin, we observed a decrease of epidermal melanin and less melanized melanosomes in lesional skin of all patients. When comparing normal and lesional skin of patients with skin type V and VI, we observed a difference in melanosome size and maturation and a switch of transferred melanosomes from single stage IV transferred melanosomes to aggregated stage I, II and III transferred melanosomes, as seen in healthy skin of skin type I to IV. CONCLUSION: Hypopigmentation in PMH seems to be the result of an altered melanogenesis based on a decrease in melanin formation and a change in the distribution of melanosomes. In lesional skin of PMH patients with skin type V and VI less melanized, aggregated melanosomes in stead of single, mature melanosomes are transferred from melanocytes to keratinocytes. This results in a decrease of epidermal melanin. Further investigations are needed to determine the precise role of Propionibacterium acnes in this alteration of melanogenesis.

Vitiligo pathogenesis: autoimmune disease, genetic defect, excessive reactive oxygen species, calcium imbalance, or what else?

The pathobiology of vitiligo has been hotly disputed for as long as one remembers, and has been a magnet for endless speculation. Evidently, the different schools of thought--ranging, e.g. from the concept that vitiligo essentially is a free-radical disorder to that of vitiligo being a primary autoimmune disease--imply very different consequences for the best therapeutic strategies that one should adopt. As a more effective therapy for this common, often disfiguring pigmentary disorder is direly needed, we must strive harder to settle the pathogenesis debate definitively--on the basis of sound experimental evidence, rather than by a war of dogmatic theories. Recognizing, however, that it is theories which tend to guide our experimental designs and choice of study parameters, the various pathogenesis theories on the market deserve to be critically, yet unemotionally re-evaluated. This Controversies feature invites you to do so, and to ask yourself: is there something important or worthwhile exploring in other pathogenesis scenarios than those already favoured by you that may help you improve your own study design, next time you have a fresh look at vitiligo? Vitiligo provides a superb model for the study of many fundamental problems in skin biology and pathology. Therefore, even if it later turns out that, as far as your own vitiligo pathogenesis concept is concerned, you have barked-up the wrong tree most of the time, chances are that you shall anyway have generated priceless new insights into skin function along the way.

Antioxidants and narrow band-UVB in the treatment of vitiligo: a double-blind placebo controlled trial.

BACKGROUND: Vitiligo is an acquired depigmenting disease with uncertain aetiopathogenesis, possibly associated with oxidative stress. Narrowband ultraviolet B phototherapy (NB-UVB) is the most widely used and effective treatment. AIM: To evaluate the clinical effectiveness of NB-UVB and the repairing of oxidative stress-induced damage, using oral supplementation with an antioxidant pool (AP). METHODS: Patients (n = 35) with nonsegmental vitiligo were enrolled in a randomized, double-blind, placebo-controlled multicentre trial. The treatment group received, for 2 months before and for 6 months during the NB-UVB treatment, a balanced AP containing alpha-lipoic acid, vitamins C and E, and polyunsaturated fatty acids. The area and number of lesions, as well as some parameters of the oxidation-reduction (redox) status of the peripheral blood mononuclear cells (PBMCs) were estimated at the beginning, after 2 months, and at the end of the trial. RESULTS: In total, 28 patients completed the study. After 2 months of AP supplementation, the catalase activity and the production of reactive oxygen species (ROS) were 121% and 57% of the basal values (P < 0.05 and P < 0.02 vs. placebo, respectively). The AP increased the therapeutic success of NB-UVB, with 47% of the patients obtaining > 75% repigmentation vs. 18% in the placebo group (P < 0.05). An increase in catalase activity to 114% (P < 0.05 vs. placebo) and decrease in ROS level of up to 60% (P < 0.02 vs. placebo) of the basal value was observed in PBMCs. Finally, the AP intake maintained the membrane lipid ratio (saturated : unsaturated fatty acids 1.8 : 3.1; P < 0.05), counteracting phototherapy-induced saturation. CONCLUSIONS: Oral supplementation with AP containing alpha-lipoic acid before and during NB-UVB significantly improves the clinical effectiveness of NB-UVB, reducing vitiligo-associated oxidative stress.

Treatment of vitiligo vulgaris with narrow-band UVB and oral Polypodium leucotomos extract: a randomized double-blind placebo-controlled study.

BACKGROUND: The first choice treatment for vitiligo vulgaris is narrow-band UVB (NB-UVB), but no satisfactory treatment exists. OBJECTIVES: To investigate if Polypodium leucotomos, an antioxidative and immunomodulatory plant extract, improves NB-UVB-induced repigmentation. METHODS: Fifty patients with vitiligo vulgaris randomly received 250 mg oral P. leucotomos or placebo three times daily, combined with NB-UVB twice weekly for 25-26 weeks. RESULTS: Repigmentation was higher in the P. leucotomos group vs. placebo in the head and neck area (44% vs. 27%, P = 0.06). Small repigmentation increases (P = n.s.) were observed for the trunk (6% increased repigmentation), extremities (4%), and hands and feet (5%) in the P. leucotomos group vs. placebo. Patients attending more than 80% of required NB-UVB sessions showed increased repigmentation in the head and neck area in the P. leucotomos group vs. placebo (50% vs. 19%, P < 0.002); no significant differences were seen in the other body areas. Patients with skin types 2 and 3 showed more repigmentation in the head and neck area in the P. leucotomos group vs. placebo (47% vs. 21%, P = 0.01), and no significant differences were seen in the other body areas. No conclusions could be drawn on skin types 4 and 5 due to low patient numbers. CONCLUSION: There is a clear trend towards an increase in repigmentation of vitiligo vulgaris affecting the head and neck area when NB-UVB phototherapy is combined with oral P. leucotomos. This effect may be more pronounced in light skin types.

Evaluation of the effects of NB-UVB in both segmental and non-segmental vitiligo affecting different body sites.

BACKGROUND: Narrow band (NB)-UVB has been used in the treatment of vitiligo for years but statistical evaluation of the clinical response in both segmental and non-segmental vitiligo patients has yet to be assessed. OBJECTIVES: Statistical evaluation of the clinical response of vitiligo patients to NB-UVB in both segmental and non-segmental types affecting different body sites. METHODS: This study included 150 patients with vitiligo either segmental (10%) or non-segmental (90%). NB-UVB therapy was given twice weekly till reaching our end point of 100% re-pigmentation or a cut point in unresponsive cases. Evaluation of the percentage of re-pigmentation was performed by total body photography and planimetry every 8 weeks. RESULTS: The overall response to therapy in the non-segmental vitiligo group demonstrated that 48% of the patients showed marked response, 27% showed moderate response and 25% showed mild response after UVB therapy. The patients showed marked response in 76.3% in face lesions, 41.9% in trunk lesions and 37.6% in limbs lesions. None of the patients in the acral areas achieved marked response. The mean duration of therapy was 7.8 months. Moreover, the results demonstrated that the earlier the patient was treated, the better the response was especially for lesions on the face, trunk and limbs. On the other hand, in the segmental vitiligo group, patients showed no more than mild response to NB-UVB whatever the site of the lesion was. No side effects were encountered with NB-UVB therapy except for aggravation of the disease in two cases and erythema in one patient who was an outdoor worker and was skin type II. CONCLUSION: The type of vitiligo, the affected anatomical area and the disease duration are important factors that influence potential re-pigmentation.

Hydroquinone and its analogues in dermatology - a potential health risk.

Hydroquinone has been used for decades as a skin lightening agent. Since January 1, 2001, its use in cosmetics has been banned. This ban is as a result of mid-term effects such as leukoderma-en-confetti/occupational vitiligo and exogenous ochronosis. However, a recent literature search on hydroquinone as a skin lightening agent suggests that possible long-term effects such as carcinogenesis may be expected as well. Metabolites of hydroquinone formed in the liver, e.g., p-benzoquinone and glutathione conjugates of hydroquinone, are mainly responsible for this. In the bone marrow, hydroquinone is oxidized into p-benzoquinone because of the high myeloperoxidase activity. Topically applied hydroquinone-containing creams may give rise to accumulation of these compounds, which can cause DNA damage and mutations. They also have the capability to disrupt protective mechanisms, whereby they facilitate further development of cancer. In the bone marrow, long-term effects such as aplastic anemia and acute myeloid leukemias may occur. Most of the evidence stems from research on benzene toxicity, which appears to arise via its metabolite hydroquinone. There is no report yet demonstrating carcinogenesis resulting from the application of hydroquinone-containing creams. However doctors should be aware of these potential health risks which were up until now disregarded.

Hypermelanocytic guttate and macular segmental hypomelanosis.

We report two sisters, 27 and 30 years of age, with a cutaneous pigmentary anomaly, which seems to be a new entity. At the age of 26 years the elder sister developed an asymptomatic and persistent rash consisting of discrete, grouped, round to oval, guttate and nummular, hypopigmented macules, 0.2-5 cm in diameter. The distribution of the lesions was unilateral. They were located on the right side of the thorax with a moderately sharp demarcation in the mid-line and ran in a segmental distribution over the right arm, hand and fingers. Microscopic examination of lesional skin scrapings was negative for fungi. Examination with Wood's light accentuated the lesions from the surrounding normal skin. The younger sister had experienced identical, mostly guttate, skin lesions for many years, which at examination were distributed on all extremities and buttocks, and to a lesser degree on the trunk, but here in a segmental distribution. Histological examination (Masson-Fontana staining) of lesional skin of both sisters was identical. A slightly thinned epidermis and a marked decrease in pigmentation of the epidermal basal layer was seen. Electron microscopic examination of lesional skin showed an overall linear increase of morphologically and cytologically normal melanocytes just above the epidermal basal membrane. At many places the density of melanocytes was so high that the keratinocytes were displaced from the basal layer. The melanocytic dendrites extended into the suprabasal layer. The keratinocytes of lesional skin showed a decreased number of melanosomes. It is paradoxical that a hypomelanotic macule shows a histological picture of an increase in normal functioning melanocytes. In all probability a deficient melanosome transfer is responsible for this unexpected phenomenon.

[Toxicological aspects and health risks associated with hydroquinone in skin bleaching formula]. / Toxicologische aspecten en gezondheidsrisico's van hydrochinon in huidbleekformuleringen.

The use of hydroquinone as a cosmetic skin-bleaching agent has been forbidden since January 2001. It is now available only on prescription. The ban has been introduced because of medium-term effects such as white patches on the skin, particularly on the face (leukoderma with confetti-like depigmentation), and subcutaneous dark collections of pigment (exogenous ochonosis). Long-term effects are a possibility; cancer being the most likely. Renal adenomas and leukaemia occurred in animal experiments indicating the nephrotoxicity and carcinogenic properties of the substance. It is now known how hydroquinone and its metabolites can cause damage to DNA and inhibit apoptosis of mutated cells. The carcinogenic action of benzene is difficult to attribute to its hydroquinone metabolite. Daily use of hydroquinone causes it to accumulate in the body as absorption into the skin is faster than excretion in the urine. The use of hydroquinone as a skin-bleaching agent is accordingly unsafe and should be completely banned. Alternatives such as azaleic acid and thioctic acid (alpha-lipoic acid) are available.

Treatment of acquired junctional melanocytic naevi by Q-switched and normal mode ruby laser.

BACKGROUND: Acquired junctional melanocytic naevi are harmless pigmented lesions of the epidermis, which can be of cosmetic concern. Various therapeutic approaches have been used in the treatment, but all these methods produce postoperative scarring or alterations in skin texture. Pigment laser treatment of benign pigmented lesions has shown a low potential for scarring by selectively targeting melanosomes in melanocytes and keratinocytes. OBJECTIVE: To find a fast, effective and safe treatment for the removal of acquired junctional melanocytic naevi. PATIENTS/METHODS: We first studied the effect of the Q-switched and normal mode ruby laser on 12 patients (eight women and four men) with acquired melanocytic naevi. The effect was monitored by histology and clinical photography. RESULTS: If the response to one treatment with the Q-switched laser mode was not completely effective, the lesions were subsequently treated with one or two sessions with the laser in normal mode. All flat lesions responded completely. After a follow-up period of 1 year they had not recurred. Slightly elevated lesions showed only a partial response, e.g. disappearance of the junctional part of the naevus but recurrence of the dermal part of the naevus. Red-brown junctional naevi as seen in skin types I and II did not respond well to ruby laser treatment. CONCLUSIONS: The Q-switched ruby laser was very successful in completely removing flat (non-palpable) acquired junctional melanocytic naevi, but not compound naevi, with one to three treatment sessions, without any scarring or pigmentary disturbance.

Aberrant expression of complement regulatory proteins, membrane cofactor protein and decay accelerating factor, in the involved epidermis of patients with vitiligo.

BACKGROUND: Vitiligo is a pigmentary disorder of the skin characterized by the complete absence of melanocytes from the lesion. Complement-activating antimelanocyte antibodies have been implicated in vitiligo pathogenesis. As membrane regulators of complement activation, membrane cofactor protein, decay accelerating factor and CD59 protect cells from elimination by autologous complement, their absence or downregulation on melanocytes may be associated with autoantibody and complement-mediated melanocyte destruction in vitiligo. OBJECTIVES: We studied the expression of these regulatory proteins in non-lesional, perilesional and lesional vitiligo skin compared with those of control specimens. METHODS: We used immunohistochemistry to study the expression of the regulatory proteins, and flow cytometric analysis of cultured melanocytes to investigate possible constitutive changes in the expression levels of these molecules. We also investigated whether melanocytes can influence keratinocyte susceptibility to autologous complement by regulating keratinocytic decay accelerating factor and membrane cofactor protein expression levels. RESULTS: Immunohistochemical data showed that expression of membrane cofactor protein and decay accelerating factor in whole epidermis was lower in lesional and perilesional skin in comparison with non-lesional skin. The reduced in situ expression appeared to be specific to vitiligo. However, coculture experiments indicated that melanocytes do not influence keratinocyte susceptibility to autologous complement. Further, flow cytometric analysis of cultured melanocytes convincingly demonstrated that non-lesional vitiligo and control melanocytes have comparable decay accelerating factor, membrane cofactor protein and CD59 expression levels. CONCLUSIONS: It is therefore concluded that there is no constitutive melanocyte defect per se that could be related to the in vivo expression of these molecules in vitiligo. Nevertheless, the present data suggest that both keratinocytes and melanocytes in the involved vitiliginous whole epidermis express lower levels of decay accelerating factor and membrane cofactor protein compared with controls that could render them more vulnerable to autologous complement attack.

Vitiligo. Pathogenesis and treatment.

Vitiligo is an acquired skin disorder caused by the disappearance of pigment cells from the epidermis that gives rise to well defined white patches which are often symmetrically distributed. The lack of melanin pigment makes the lesional skin more sensitive to sunburn. Vitiligo can be cosmetically disfiguring and it is a stigmatizing condition, leading to serious psychologic problems in daily life. It occurs worldwide in about 0.5% of the population and it occurs as frequently in males as it does in females. The cause is unknown, but might involve genetic factors, autoimmunity, neurologic factors, toxic metabolites, and lack of melanocyte growth factors. Since a causative (gene) treatment is not (yet) available, current modalities are directed towards stopping progression and to achieving repigmentation in order to repair the morphology and functional deficiencies of the depigmented skin areas. Many treatments have been used for some time; however; there are some new developments: narrowband ultraviolet (UV) B (311 nm) therapy, the combination of corticosteroid cream + UVA therapy, and the transplantation of autologous pigment cells in various modalities. In widespread vitiligo, residual pigment can be removed by depigmentation agents. Sunscreens, camouflage products, and good guidance may help the patient cope better with the disease.

Linkage and association of HLA class II genes with vitiligo in a Dutch population.

BACKGROUND: Serological typing of HLA has shown discrepancies in HLA associations with vitiligo in different ethnic populations. OBJECTIVES: To perform genotyping of HLA class II genes on a Dutch vitiligo population in order clearly to identify susceptible and protective HLA alleles in vitiligo. METHODS: HLA typing was carried out by amplifying genomic DNA by polymerase chain reaction (PCR) followed by dot-blot hybridization with sequence-specific oligonucleotides (SSO). Fifty Dutch vitiligo probands, and their parents (150 individuals) and 204 healthy controls were studied. RESULTS: Family-based case-control association studies and linkage disequilibrium analysis showed the linkage and association of DRB4*0101 allele with vitiligo (P(c) = 0.0016, relative risk = 2.21). The family-based association study also provided evidence for linkage and association of DQB1*0303 allele with vitiligo (chi(2) = 7.36, P = 0.006). We measured the clinical relevance of the test by calculating the prevalence corrected positive predictive values (PcPPV). The PcPPV of disease for the DRB4*0101 allele was 0.017 and for the DRB4*0101/0101 genotype was 0.0358. In other words, a DRB4*0101/0101 genotype carries a 3.58% risk of developing vitiligo. CONCLUSIONS: Both DRB4*0101 and DQB1*0303 alleles provide significant susceptibility for vitiligo.

Mucopolysaccharides from psyllium involved in wound healing.

Mucopolysaccharides derived from the husk of psyllium (Plantago ovata) have properties beneficial for wound cleansing and wound healing. Recent studies indicate that these mucopolysaccharides also limit scar formation. Our in vitro and in vivo studies aimed to investigate the mechanisms involved, e.g., fluid absorption, bacterial adherence and in vitro stimulatory effects on macrophages, which are pivotal in wound healing. The mucopolysaccharides contained in a sachet (Askina Cavity) or in a hydrocolloid mixture (Askina Hydro) were found to have a gradual and sustained absorbency over a period of 7 days, amounting to 4-6 times their weight in water. The swelling index was 9 mm after 312 h. Adherence of wound bacteria to the mucopolysaccharides started after 2 h and was more pronounced after 3 h. Semiquantitative measurements of bacterial adherence used centrifugation and subsequent optical density determinations of supernatant. These confirmed the strong adherence potential of psyllium particles. Lactic acid dehydrogenase staining of pretreated cultured human skin explants did not reveal toxicity of the mucopolysaccharides derived from psyllium husk. Langerhans' cell migration from the epidermis was negligible and interleukin-1 beta expression in the explants was not significant, supporting the very low allergenic potential of psyllium. The characteristics of mucopolysaccharide granulate derived from psyllium husk in Askina Cavity and Askina Hydro related to fluid absorption, bacterial adherence, biocompatibility, stimulation of macrophages, irritancy response and allergenicity showed an optimal profile, supporting the good clinical performance of wound healing products containing psyllium husk.

Expression and modulation of apoptosis regulatory molecules in human melanocytes: significance in vitiligo.

Although the aetiology of the hypopigmentary disorder vitiligo is ill understood, it is clear that pigment producing cells are absent from vitiliginous lesional skin. The present study was designed to investigate the possible role of melanocyte-expressed apoptosis regulatory molecules in melanocyte disappearance. Flow cytometric evaluation of p53, p21, Bcl-2 and Bax revealed no differences in in vitro expression levels between normal control and non-lesional melanocytes. Moreover, no in situ immunohistological differences were observed in melanocytes present in control, non-lesional and perilesional skin. However, an enhanced number of p53+ nuclei, in the absence of detectable p21 expression, was detected in involved areas. The observed p53 expression pattern did not involve melanocytes and could be the result of ultraviolet (UV) A irradiation. Further, we showed that UVB is capable of modulating melanocyte-expressed apoptosis regulatory molecules. Consequently, a lethal dose of UVB was given to two groups of cultured normal control and non-lesional melanocytes. No significant differences were found when comparing the percentages and kinetics of UVB-induced apoptosis in these groups. In conclusion, our results indicate that the relative apoptosis susceptibility of melanocytes in vitiligo is comparable with that of normal control cells. It is therefore unlikely that vitiligo is causally related to dysregulation of apoptosis regulatory molecules.